Areas of Research and other interests:
Tags:
Chemistry,
Nuclear Magnetic Resonance Spectroscopy,
NMR,
Metabolomics,
Structure elucidation by NMR,
Antioxidants,
Brain metabolism,
Cancer
Publications
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Nardini, Greta; Liland, Kristian Hovde; Pauli, Guido F.; Wubshet, Sileshi Gizachew; Wilkins, Alistair L. & Rise, Frode
[Show all 9 contributors for this article]
(2026).
NMR-Based Quantification of Collagen Content in Protein Hydrolysates.
Journal of Agricultural and Food Chemistry.
ISSN 0021-8561.
74(6),
p. 5627–5639.
doi:
https:/pubs.acs.org/doi/10.1021/acs.jafc.5c13447.
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Certain functional food and dietary supplement ingredients contain bioactive peptides whose bioactivity is determined by their chain length, composition, and specific sequence of the amino acids. This study investigated collagenous peptides from the valorization of poultry side streams, which, for example, have inhibitory activities against therapeutic targets for the management of blood pressure and blood glucose. To overcome the specificity challenges of conventional amino acid analysis, the aim was to establish and validate a quantitative 1H NMR (qHNMR) method for the quantification of hydroxyproline as a marker of collagen content in poultry hydrolysates. Indeed, qHNMR provides a rapid structure-specific quantification, and it is highly informative, reproducible, and accurate. The effect of different acidic solvents was investigated using quantum mechanics (QM)-based 1H iterative functionalized spin analysis (HifSA). Comparison of conventional integration (int-) with QM-qHNMR revealed limitations of the former approach and highlighted the increased accuracy and specificity of QM-qHNMR.
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Uhlig, Silvio; So̷rnes, Kristian; Mineeva, Evangeliia; Rise, Frode; Grutle, Lene & Morisbak, Else
[Show all 9 contributors for this article]
(2025).
Nucleophilic Addition of Thiols to Methacrylates for Biomedical Applications Revisited.
Chemical Research in Toxicology.
ISSN 0893-228X.
38(9),
p. 1535–1547.
doi:
10.1021/acs.chemrestox.5c00179.
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Composites are popular materials for, among others, restorative dentistry because of their favorable mechanical and esthetic properties and direct-filling applications. The raw materials for such composites usually consist of filler particles embedded in a matrix of dimethacrylate monomers that are polymerized in situ. Because the raw materials cannot polymerize completely, residual monomers leach out over time. The conjugation of methacrylates with sulfur compounds has been recognized as an important reaction as well as a detoxification pathway; thus, leached monomers are expected to undergo chemical reactions with various biomolecules that contain thiol functionalities. To understand the reaction of dental methacrylate monomers with thiols, we studied the reaction of 2-hydroxyethyl methacrylate (HEMA), triethylene glycol dimethacrylate, urethane dimethacrylate, and bisphenol A diglycidyl methacrylate with the model thiol 2-mercaptoethanol using liquid chromatography coupled to low- and high-resolution mass spectrometry (LC–MS and LC–HRMS). The results indicate that thiols react readily with the conjugated double bond, and with methacrylate half-lives of 7–21 h under pseudo-first-order reaction conditions and at neutral pH. Dimethacrylates first formed a monoaddition product, while thiol addition to the second acrylate moiety was observed on a longer time scale. The reaction of HEMA with l-cysteine and l-glutathione was studied in more detail using HRMS and NMR spectroscopy. The reaction rates were substantially higher than for the reaction with mercaptoethanol, and NMR analysis revealed the presence of two isomeric reaction products. Structural characterization also included the identification and assignment of sulfoxides of HEMA-cysteine and HEMA-glutathione. Using the characterized HEMA–thiols as reference standards for LC–HRMS, we demonstrated the presence of HEMA-glutathione, HEMA-cysteine, their sulfoxides, and a putative HEMA-cysteinylglycine in a human osteoblast-like cell line following exposure to HEMA.
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Alexandrescu, Cristina; Guttorm, Sander; Elgstøen, Katja B. Prestø; Rise, Frode & Wilson, Steven Ray Haakon
(2025).
Exploring nuclear magnetic resonance spectroscopy for the analysis of dried blood spots.
Talanta: The International Journal of Pure and Applied Analytical Chemistry.
ISSN 0039-9140.
297(Part B).
doi:
10.1016/j.talanta.2025.128809.
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Dried blood spots (DBS) offer a practical and relatively non-invasive method for sample collection. Here, we evaluate the feasibility of applying 1H NMR spectroscopy to metabolomic analysis of DBS. Various solvent suppression techniques and extraction protocols were tested using aqueous and methanolic solvents. Methanol was found to provide heightened metabolite recovery with fewer interfering macromolecular signals compared to aqueous buffers, supporting its use as a preferred extraction solvent. Additional experimental variables, such as extraction time and the number of DBS punches, were optimized to improve spectral quality. Potentially interfering contaminations from sampling materials and consumables were identified. As a demonstration of practical application, DBS cards were distributed and returned via international and local transport, and their metabolic profiles were assessed. Despite some variation among transported samples, individual-specific metabolic signatures remained discernible, suggesting a robustness of the method for comparative analyses. Overall, these initial results support the use of NMR as a complementary technique to mass spectrometry for DBS-based metabolomics, particularly when simplicity, reproducibility, and robustness is prioritized, and when overall sensitivity is less of a factor.
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Bakke, Kine Mari; Bousquet, Paula; Meltzer, Sebastian; Bjørnetrø, Tonje; Rise, Frode & Wilkins, Alistair Lawrence
[Show all 8 contributors for this article]
(2025).
Serum metabolite levels identify incipient metastatic progression of rectal cancer.
Communications Medicine.
5.
doi:
10.1038/s43856-025-00868-w.
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Background
The cellular metabolism undergoes reprogramming during the metastatic process. We hypothesised that serum metabolites at the time of primary tumour diagnosis might identify rectal cancer patients prone to metastatic progression.
Methods
One hundred twenty-three rectal cancer patients from a prospective observational biomarker study were followed up to 5 years after study entry. We have assessed metabolites in serum sampled at the time of diagnosis by 1H-nuclear magnetic resonance spectroscopy, using the internal reference trimethylsilylpropanoic acid for quantification.
Results
Here we show that patients who develop overt metastatic disease more than 6 months after the primary tumour diagnosis have elevated serum levels (Kruskal-Wallis test) of alanine (P = 0.005), lactate (P = 0.023), pyruvate (P = 0.041) and citrate (P = 0.007) compared to those without metastases at the 5-year follow-up or with metastases already 6 months or sooner after the cancer diagnosis. Patients with serum citrate above 0.24 mmol/L have poorer progression-free survival compared to those with levels below (P < 0.001; log-rank test).
Conclusions
We observe a distinct serum metabolite profile, in particular involving citrate to the best of our knowledge shown for the first time clinically, in rectal cancer patients at heightened risk of metastasis already when the primary tumour is diagnosed, offering insights into the metabolism of metastatic progression.
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Kogler, Stian; Skottvoll, Frøydis Sved; Hruskova, Helena; Rise, Frode; Aizenshtadt, Aleksandra & Krauss, Stefan Johannes Karl
[Show all 9 contributors for this article]
(2025).
Electromembrane Extraction Provides Unprecedented Selectivity for Drugs in Cell Culture Media Used in Organoid and Organ-on-Chip Systems.
Analytical Chemistry.
ISSN 0003-2700.
97(9),
p. 4923–4931.
doi:
10.1021/acs.analchem.4c04994.
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The use of organoids and organ-on-chip technologies as nonanimal methodologies in drug discovery and personalized medicine is rapidly expanding. However, the complexity and small volumes of organoid culture samples present significant analytical challenges, e.g., in drug analysis using liquid chromatography–mass spectrometry (LC–MS). Essentially an electrophoresis across an oil membrane, electromembrane extraction (EME) offers a promising approach for measuring drugs, as it is, for example, compatible with small samples such as organoid and organ-on-chip formats. Given the potential of the technology, there is a need to assess the extraction purity of EME extracts to ensure EME’s compatibility with high-throughput, downstream analysis. This study evaluates the effectiveness of EME for sample cleanup in various common cell culture media used for organoids and organs-on-chips. The media were spiked with 90 small-molecule drugs. Using gel electrophoresis (sodium dodecyl sulfate polyacrylamide gel electrophoresis), high-resolution nuclear magnetic resonance spectroscopy, and LC–MS, we demonstrate that EME provides exhaustive removal of unwanted medium components (proteins, polar molecules, and apolar/neutral molecules) while selectively extracting the spiked small-molecule drugs. The approach was demonstrated with human stem-cell-derived liver organoids, allowing simple detection and monitoring of telltale cytochrome P450 metabolism. Taken together, our observations highlight an unprecedented ability of EME to provide sample cleanup for drug analysis in matrixes compatible with organoids and organ-on-chip technology.
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Selwood, Andrew I.; Miles, Christopher Owen; Wilkins, Alistair Lawrence; Rise, Frode; Finch, Sarah C. & Ginkel, Roel van
(2025).
Structural Characterization of Pinnatoxin Isomers.
Marine Drugs.
23(3).
doi:
10.3390/md23030103.
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Pinnatoxins, a group of marine biotoxins primarily produced by the dinoflagellate Vulcanodinium rugosum, have garnered significant attention due to their potent toxic effects and widespread distribution in marine ecosystems. LC–MS analysis of shellfish and V. rugosum cultures revealed the presence of previously unidentified isomers of pinnatoxins D, E, F, and H, at levels approximately six times lower than those of known isomers. The chemical structures of these isopinnatoxins were determined using a combination of LC–MS/MS and NMR spectroscopy, which demonstrated that the isomerization of each pinnatoxin occurred through the opening and recyclization of the spiro-linked tetrahydropyranyl D-ring to form a smaller tetrahydrofuranyl ring. The acute toxicity of isopinnatoxin E was determined by intraperitoneal injection into mice and was found to be significantly lower than that of pinnatoxin E. Given their low toxicity and low abundance, it is unlikely that isopinnatoxins contribute significantly to the overall toxicity of pinnatoxins.
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Mudge, Elizabeth M.; Wilkins, Alistair Lawrence; Murray, J. Sam; Rise, Frode & Miles, Christopher Owen
(2024).
Investigation of 44-methylgambierone reactivity with periodate: Structural reassignment, solvent instability and formation of a furanoid analogue.
Toxicon.
ISSN 0041-0101.
251.
doi:
10.1016/j.toxicon.2024.108154.
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Butt, Hussain Shakeel; Ulriksen, Emilie Steinbakk; Rise, Frode; Wangensteen, Helle; Duus, Jens Øllgaard & Inngjerdingen, Marit
[Show all 7 contributors for this article]
(2024).
Structural elucidation of novel pro-inflammatory polysaccharides from Daphne mezereum L.
Carbohydrate Polymers.
ISSN 0144-8617.
324:121554,
p. 1–15.
doi:
10.1016/j.carbpol.2023.121554.
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Daphne mezereum L., an important medicinal plant in Scandinavian folk medicine, was used to treat ailments such as diarrhea, swelling and stomach pain. A range of natural compounds have been isolated, but little attention has been given to the polysaccharides in this plant. Previous work in our group have shown that a polysaccharide enriched fraction from the bark of D. mezereum exhibited pro-inflammatory effects. To pursue this further, the aim of the present work was to isolate and characterize these polysaccharides. From the ethanol-precipitate of a water extract, one neutral (DMP-NF) and one acidic (DMP-AF) fraction was isolated by anion-exchange chromatography. GC, GC–MS and 1D- and 2D-NMR were used to characterize the polysaccharide structures. DMP-NF appeared to be a mixture of arabinan, arabinogalactan and hemicelluloses such as xyloglucan, mannan and xylan. DMP-AF contained a pectic polysaccharide mainly consisting of an unusually long homogalacturonan backbone. Enzymatic treatment by pectinase of DMP-AF yielded DMP-ED, which contained a rhamnogalacturonan-I backbone with arabinan, galactan and arabinogalactan side chains. Both DMP-NF and DMP-ED induced IFN-γ and TNF-α secretion in peripheral blood mononuclear cells (PBMCs), DMP-ED being the most potent fraction. DMP-AF was less active, which might be due to a less sterically available rhamnogalacturonan-I domain.
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Hassel, Bjørnar; Sørnes, Kristian; Elsais, Ahmed; Cordero, Patricia Reyes; Frøland, Anne-Sofie & Rise, Frode
(2024).
Glyceraldehyde metabolism in mouse brain and the entry of blood-borne glyceraldehyde into the brain.
Journal of Neurochemistry.
ISSN 0022-3042.
doi:
10.1111/jnc.16158.
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D-Glyceraldehyde, a reactive aldehyde metabolite of fructose and glucose, is neurotoxic in vitro by forming advanced glycation end products (AGEs) with neuronal proteins. In Alzheimer's disease brains, glyceraldehyde-containing AGEs have been detected intracellularly and in extracellular plaques. However, little information exists on how the brain handles D-glyceraldehyde metabolically or if glyceraldehyde crosses the blood–brain barrier from the circulation into the brain. We injected [U-13C]-D-glyceraldehyde intravenously into awake mice and analyzed extracts of serum and brain by 13C nuclear magnetic resonance spectroscopy. 13C-Labeling of brain lactate and glutamate indicated passage of D-glyceraldehyde from blood to brain and glycolytic and oxidative D-glyceraldehyde metabolism in brain cells. 13C-Labeling of serum glucose and lactate through hepatic metabolism of [U-13C]-D-glyceraldehyde could not explain the formation of 13C-labeled lactate and glutamate in the brain. Cerebral glyceraldehyde dehydrogenase and reductase activities, leading to the formation of D-glycerate and glycerol, respectively, were 0.27–0.28 nmol/mg/min; triokinase, which phosphorylates D-glyceraldehyde to D-glyceraldehyde-3-phosphate, has been demonstrated previously at low levels. Thus, D-glyceraldehyde metabolism toward glycolysis could proceed both through D-glycerate, glycerol, and D-glyceraldehyde-3-phosphate. The aldehyde group of D-glyceraldehyde was overwhelmingly hydrated into a diol in aqueous solution, but the diol dehydration rate greatly exceeded glyceraldehyde metabolism and did not restrict it. We conclude that (1) D-glyceraldehyde crosses the blood–brain barrier, and so blood-borne glyceraldehyde could contribute to AGE formation in the brain, (2) glyceraldehyde is taken up and metabolized by brain cells. Metabolism thus constitutes a detoxification mechanism for this reactive aldehyde, a mechanism that may be compromised in disease states.
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Fu, Yu-ping; Peng, Xi; Zhang, Chao-Wen; Jiang, Quan-Xing; Li, Cen-Yu & Paulsen, Berit Smestad
[Show all 21 contributors for this article]
(2023).
Salvia miltiorrhiza polysaccharide and its related metabolite 5-methoxyindole-3-carboxaldehyde ameliorate experimental colitis by regulating Nrf2/Keap1 signaling pathway.
Carbohydrate Polymers.
ISSN 0144-8617.
306.
doi:
10.1016/j.carbpol.2023.120626.
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The roots of Salvia miltiorrhiza have been used in Traditional Chinese Medicine for thousands of years. However, tons of aerial parts of this plant are usually discarded in the production of roots preparation. To make better use of these plant resources, the polysaccharide isolated from the aerial part of S. miltiorrhiza was investigated for its potential protection against intestinal diseases. A pectic polysaccharide (SMAP-1) was isolated and characterized being composed of homogalacturonan as the main chain and rhamnogalacturonan type I as ramified region, with side chains including arabinans and possible arabinogalactan type I and II. SMAP-1 exhibited robust protective effects against dextran sodium sulfate (DSS)-induced colitis and restored colitis symptoms, colonic inflammation, and barrier functions. Anti-oxidative effects were also observed by up-regulating Nrf2/Keap1 signaling pathway. Additionally, the level of serum 5-methoxyindole-3-carboxaldehyde (5-MC) was restored by SMAP-1 identified in metabolomic analysis, being correlated with the aforementioned effects. Protection against oxidative stress on intestinal porcine enterocyte cells (IPEC-J2) by 5-MC was observed through the activation of Nrf2/Keap1 system, as also shown by SMAP-1. In conclusion, SMAP-1 could be a promising candidate for colitis prevention, and 5-MC could be the signal metabolite of SMAP-1 in protecting against oxidative stress in the intestine.
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Li, Li-Xia; Chen, Meng-Si; Zhang, Zi-Yu; Paulsen, Berit Smestad; Rise, Frode & Huang, Chao
[Show all 17 contributors for this article]
(2022).
Structural features and antioxidant activities of polysaccharides from different parts of Codonopsis pilosula var. modesta (Nannf.) L. T. Shen.
Frontiers in Pharmacology.
13,
p. 937581–937581.
doi:
10.3389/fphar.2022.937581.
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In this study, three acidic polysaccharides from different plant parts of Codonopsis pilosula var. Modesta (Nannf.) L. T. Shen were obtained by ion exchange chromatography and gel filtration chromatography, and the yields of these three polysaccharides were different. According to the preliminary experimental results, the antioxidant activities of the polysaccharides from rhizomes and fibrous roots (CLFP-1) were poor, and was thus not studied further. Due to this the structural features of polysaccharides from roots (CLRP-1) and aerial parts (CLSP-1) were the object for this study and were structurally characterized, and their antioxidant activities were evaluated. As revealed by the results, the molecular weight of CLRP-1and CLSP-1 were 15.9 kDa and 26.4 kDa, respectively. The monosaccharide composition of CLRP-1 was Ara , Rha, Fuc, Xyl, Man, Gal, GlcA, GalA in a ratio of 3.8: 8.4: 1.0: 0.8: 2.4: 7.4: 7.5: 2.0: 66.7, and Ara , Rha, Gal, GalA in a ratio of 5.8: 8.9: 8.0: 77.0 in for CLSP-1. The results of structural elucidation indicated that both CLRP-1 and CLSP-1 were pectic polysaccharides, mainly composed of 1, 4-linked galacturonic acid with long homogalacturonan regions. Arabinogalactan type I and arabinogalactan type II were presented as side chains. The antioxidant assay in IPEC-J2 cells showed that both CLRP-1 and CLSP-1 promoted cell viability and antioxidant activity, which significantly increase the level of total antioxidant capacity and the activity of superoxide dismutase, catalase, and decrease the content of malondialdehyde. Moreover, CLRP-1 and CLSP-1 also showed powerful antioxidant abilities in Caenorhabditis elegans and might regulate the nuclear localization of DAF-16 transcription factor, induced antioxidant enzymes activities, and further reduced reactive oxygen species and malondialdehyde contents to increase the antioxidant ability of Caenorhabditis elegans . Thus, these finding suggest that CLRP-1 and CLSP-1 could be used as potential antioxidants.
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Murray, J. Sam; Finch, Sarah C.; Mudge, Elizabeth M.; Wilkins, Alistair Lawrence; Puddick, Jonathan & Harwood, D. Tim
[Show all 10 contributors for this article]
(2022).
Structural Characterization of Maitotoxins Produced by Toxic Gambierdiscus Species.
Marine Drugs.
20(7).
doi:
10.3390/md20070453.
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Identifying compounds responsible for the observed toxicity of the Gambierdiscus species is a critical step to ascertaining whether they contribute to ciguatera poisoning. Macroalgae samples were collected during research expeditions to Rarotonga (Cook Islands) and North Meyer Island (Kermadec Islands), from which two new Gambierdiscus species were characterized, G. cheloniae CAWD232 and G. honu CAWD242. Previous chemical and toxicological investigations of these species demonstrated that they did not produce the routinely monitored Pacific ciguatoxins nor maitotoxin-1 (MTX-1), yet were highly toxic to mice via intraperitoneal (i.p.) injection. Bioassay-guided fractionation of methanolic extracts, incorporating wet chemistry and chromatographic techniques, was used to isolate two new MTX analogs; MTX-6 from G. cheloniae CAWD232 and MTX-7 from G. honu CAWD242. Structural characterization of the new MTX analogs used a combination of analytical chemistry techniques, including LC–MS, LC–MS/MS, HR–MS, oxidative cleavage and reduction, and NMR spectroscopy. A substantial portion of the MTX-7 structure was elucidated, and (to a lesser extent) that of MTX-6. Key differences from MTX-1 included monosulfation, additional hydroxyl groups, an extra double bond, and in the case of MTX-7, an additional methyl group. To date, this is the most extensive structural characterization performed on an MTX analog since the complete structure of MTX-1 was published in 1993. MTX-7 was extremely toxic to mice via i.p. injection (LD50 of 0.235 µg/kg), although no toxicity was observed at the highest dose rate via oral administration (155.8 µg/kg). Future research is required to investigate the bioaccumulation and likely biotransformation of the MTX analogs in the marine food web.
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Dénou, Adama; Togola, Adiaratou; Inngjerdingen, Kari Tvete; Moussavi, Nastaran; Rise, Frode & Zou, Yuanfeng
[Show all 13 contributors for this article]
(2022).
Isolation, characterisation and complement fixation activity of acidic polysaccharides from Argemone mexicana used as antimalarials in Mali.
Pharmaceutical Biology.
ISSN 1388-0209.
60(1),
p. 1278–1285.
doi:
10.1080/13880209.2022.2089691.
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Context Global studies on Argemone mexicana L. (Papaveraceae) traditionally used against malaria in Mali are limited to its low-mass compounds activities, and little information on its bioactive polysaccharides is available. Objective This study determines the structure and the immunomodulatory activity of polysaccharides from aerial parts of A. mexicana. Materials and methods Acidic polysaccharides from this plant material named HMAmA1 and HMAmA2 were isolated from water extracts. Their monosaccharide composition was determined by gas chromatography. Glycosidic linkages were determined using GC-MS. NMR was also applied. The polymers were tested for effects on the human complement system in vitro at different doses. Results The monosaccharide composition showed that the two polysaccharides contained in different amounts the following monomers: arabinose, rhamnose, galactose, and galacturonic acid. Overall structural analysis showed the presence of a low ratio of 1,2-linked rhamnose compared to 1,4-linked galacturonic acid with arabinogalactans substituted on position 4 of rhamnose. NMR data showed the presence of galacturonans alternated by rhamnogalacturonans bearing arabinose and galactose units. α-Linkages were found for l-arabinose, l-rhamnose and d-galacturonic acid, while β-linkages were found for d-galactose. The two polysaccharides exhibited strong complement fixation activities, with HMAmA1 being the highest potent fraction. ICH50 value of HMAmA1 was 5 µg/mL, compared to the control BPII being 15.9 µg/mL. Discussion and conclusions Polysaccharides form A. mexicana presented a complement fixation effect. The complement system is an important part of the immune defense, and compounds acting on the cascade are of interest. Therefore, these polymers may be useful as immunodulatory agents.
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Fu, Yu-ping; Li, Cen-Yu; Peng, Xi; Zou, Yuan-Feng; Rise, Frode & Paulsen, Berit Smestad
[Show all 8 contributors for this article]
(2022).
Polysaccharides from Aconitum carmichaelii leaves: Structure, immunomodulatory and anti-inflammatory activities.
Carbohydrate Polymers.
ISSN 0144-8617.
291,
p. 119655–119655.
doi:
10.1016/j.carbpol.2022.119655.
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Roots of Aconitum carmichaelii are used in Asian countries due to its content of bioactive alkaloids. In the production of root preparations, tons of leaves are usually discarded, leading to a huge waste of herbal material. The aim of this study is to investigate the polysaccharides in these unutilized leaves. A neutral polysaccharide (AL-N) appeared to be a mixture of heteromannans, and two purified acidic polysaccharides (AL-I-I and AL-I-II) were shown to be pectins containing a homogalacturonan backbone substituted with terminal β-Xylp-units. AL-I-I consisted of a type-I rhamnogalacturonan core, with arabinan and type-II arabinogalactan domains while AL-I-II was less branched. AL-N and AL-I-I were able to modulate the complement system, while AL-I-II was inactive. Interestingly, AL-N, AL-I-I and AL-I-II were shown to exert anti-inflammatory effects on porcine enterocyte IPEC-J2 cells. AL-I-I and AL-I-II were able to down-regulate the expression of toll-like receptor 4 (TLR4) and nucleotide-binding oligomerization domain 1 (NOD1).
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Zawadzka, Malgorzata Elzbieta; Racz, Beatrix; Ambrosini, Dario; Görbitz, Carl Henrik; Morth, Jens Preben & Wilkins, Alistair L.
[Show all 12 contributors for this article]
(2021).
Searching for a UV-filter in the eyes of high-flying birds.
Scientific Reports.
11(1).
doi:
10.1038/s41598-020-79533-2.
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Abstract The eye lens is a unique organ as no cells can be replaced throughout life. This makes it decisive that the lens is protected against damaging UV-radiation. An ultraviolet (UV)-absorbing compound of unknown identity is present in the aqueous humor of geese (wild and domestic) and other birds flying at high altitudes. A goose aqueous humor extract, that was believed to contain the UV protective compound which was designated as “compound X”, was fractionated and examined using a variety of spectroscopic techniques including LC–MS and high field one- and two dimensional-NMR methods. A series of compounds were identified but none of them appeared to be the UV protective “compound X”. It may be that the level of the UV protective compound in goose aqueous humor is much less than the compounds identified in our investigation, or it may have been degraded by the isolation and chromatographic purification protocols used in our investigations.
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Ellefsen, Christiane Færestrand; Wold, Christian Winther; Wilkins, Alistair L.; Rise, Frode & Samuelsen, Anne Berit C.
(2021).
Water-soluble polysaccharides from Pleurotus eryngii fruiting bodies, their activity and affinity for Toll-like receptor 2 and dectin-1.
Carbohydrate Polymers.
ISSN 0144-8617.
264.
doi:
10.1016/j.carbpol.2021.117991.
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The mushroom cell wall contains polysaccharides that can activate cells of the innate immune system through receptors such as Toll-like receptors (TLR) and dectin-1. In the present study, Pleurotus eryngii polysaccharide fractions containing a 3-O methylated mannogalactan and (1→3)/(1→6)-β-d-glucans were isolated and extensively characterized by 2D NMR and methylation analysis. Traces of a (1→3)-α-d-glucan and a (1→2)-α-d-mannan were also observed. Affinity for TLR2, TLR2-TLR6 and dectin-1 using HEK-cells expressing the relevant receptor genes was tested. PeWN, containing the 3-O methylated mannogalactan, was inactive towards TLR2, whereas fraction PeWB, containing more β-glucan, activated the TLR2-TLR6 heterodimer. Activation of the human β-glucan receptor dectin-1 correlated with the amount of β-glucan in each fraction. Nitric oxide and cytokine supernatant levels of D2SC/1 dendritic cells stimulated with the P. eryngii fractions and interferon-γ were low to moderate. The results indicate that the immunomodulatory activity of water-soluble P. eryngii polysaccharide fractions is modest.
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Xu, Kaiqi; Chatzitakis, Athanasios Eleftherios; Backe, Paul Hoff; Ruan, Qiushi; Tang, Junwang & Rise, Frode
[Show all 8 contributors for this article]
(2021).
In situ cofactor regeneration enables selective CO2 reduction in a stable and efficient enzymatic photoelectrochemical cell.
Applied Catalysis B: Environmental.
ISSN 0926-3373.
296.
doi:
10.1016/j.apcatb.2021.120349.
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Mimicking natural photosynthesis by direct photoelectrochemical (PEC) reduction of CO2 to chemicals and fuels requires complex cell assemblies with limitations in selectivity, efficiency, cost, and stability. Here, we present a breakthrough cathode utilizing an oxygen tolerant formate dehydrogenase enzyme derived from clostridium carboxidivorans and coupled to a novel and efficient in situ nicotinamide adenine dinucleotide (NAD+/NADH) regeneration mechanism through interfacial electrochemistry on g-C3N4 films. We demonstrate stable (20 h) aerobic PEC CO2-to-formate reduction at close to 100 % faradaic efficiency and unit selectivity in a bio-hybrid PEC cell of minimal engineering with optimized Ta3N5 nanotube photoanode powered by simulated sunlight with a solar to fuel efficiency of 0.063 %, approaching that of natural photosynthesis.
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Vitova, Milada; Lanta, Vojtech; Cizkova, Maria; Jakubec, Martin; Rise, Frode & Halskau, Øyvind
[Show all 8 contributors for this article]
(2021).
The biosynthesis of phospholipids is linked to the cell cycle in a model eukaryote.
Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids.
ISSN 1388-1981.
1866(8).
doi:
10.1016/j.bbalip.2021.158965.
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The structural challenges faced by eukaryotic cells through the cell cycle are key for understanding cell viability and proliferation. We tested the hypothesis that the biosynthesis of structural lipids is linked to the cell cycle. If true, this would suggest that the cell's structure is important for progress through and perhaps even control of the cell cycle. Lipidomics (31P NMR and MS), proteomics (Western immunoblotting) and transcriptomics (RT-qPCR) techniques were used to profile the lipid fraction and characterise aspects of its metabolism at seven stages of the cell cycle of the model eukaryote, Desmodesmus quadricauda. We found considerable, transient increases in the abundance of phosphatidylethanolamine during the G1 phase (+35%, ethanolamine phosphate cytidylyltransferase increased 2·5×) and phosphatidylglycerol (+100%, phosphatidylglycerol synthase increased 22×) over the G1/pre-replication phase boundary. The relative abundance of phosphatidylcholine fell by ~35% during the G1. N-Methyl transferases for the conversion of phosphatidylethanolamine into phosphatidylcholine were not found in the de novo transcriptome profile, though a choline phosphate transferase was found, suggesting that the Kennedy pathway is the principal route for the synthesis of PC. The fatty acid profiles of the four most abundant lipids suggested that these lipids were not generally converted between one another. This study shows for the first time that there are considerable changes in the biosynthesis of the three most abundant phospholipid classes in the normal cell cycle of D. quadricauda, by margins large enough to elicit changes to the physical properties of membranes.
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Wilkins, Alistair Lawrence; Rundberget, Thomas; Sandvik, Morten; Rise, Frode; Knudsen, Brent K. & Kilcoyne, Jane
[Show all 13 contributors for this article]
(2021).
Identification of 24-O-β-d-Glycosides and 7-Deoxy-Analogues of Okadaic Acid and Dinophysistoxin-1 and -2 in Extracts from Dinophysis Blooms, Dinophysis and Prorocentrum Cultures, and Shellfish in Europe, North America and Australasia.
Toxins.
13(8).
doi:
10.3390/toxins13080510.
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Two high-mass polar compounds were observed in aqueous side-fractions from the purification of okadaic acid (1) and dinophysistoxin-2 (2) from Dinophysis blooms in Spain and Norway. These were isolated and shown to be 24-O-β-d-glucosides of 1 and 2 (4 and 5, respectively) by nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, and enzymatic hydrolysis. These, together with standards of 1, 2, dinophysistoxin-1 (3), and a synthetic specimen of 7-deoxy-1 (7), combined with an understanding of their mass spectrometric fragmentation patterns, were then used to identify 1–5, the 24-O-β-d-glucoside of dinophysistoxin-1 (6), 7, 7-deoxy-2 (8), and 7-deoxy-3 (9) in a range of extracts from Dinophysis blooms, Dinophysis cultures, and contaminated shellfish from Spain, Norway, Ireland, Canada, and New Zealand. A range of Prorocentrum lima cultures was also examined by liquid chromatography–high resolution tandem mass spectrometry (LC–HRMS/MS) and was found to contain 1, 3, 7, and 9. However, although 4–6 were not detected in these cultures, low levels of putative glycosides with the same exact masses as 4 and 6 were present. The potential implications of these findings for the toxicology, metabolism, and biosynthesis of the okadaic acid group of marine biotoxins are briefly discussed.
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König, Nico; Willner, Lutz; Carlström, Göran; Zinn, Thomas; Knudsen, Kenneth Dahl & Rise, Frode
[Show all 8 contributors for this article]
(2020).
Spherical Micelles with Nonspherical Cores: Effect of Chain Packing on the Micellar Shape.
Macromolecules.
ISSN 0024-9297.
53(23),
p. 10686–10698.
doi:
10.1021/acs.macromol.0c01936.
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Self-assembly of amphiphilic polymers into micelles is an archetypical example of a “self-confined” system due to the formation of micellar cores with dimensions of a few nanometers. In this work, we investigate the chain packing and resulting shape of Cn-PEOx micelles with semicrystalline cores using small/wide-angle X-ray scattering (SAXS/WAXS), contrast-variation small-angle neutron scattering (SANS), and nuclear magnetic resonance spectroscopy (NMR). Interestingly, the n-alkyl chains adopt a rotator-like conformation and pack into prolate ellipses (axial ratio ϵ ≈ 0.5) in the “crystalline” region and abruptly arrange into a more spheroidal shape (ϵ ≈ 0.7) above the melting point. We attribute the distorted spherical shape above the melting point to thermal fluctuations and intrinsic rigidity of the n-alkyl blocks. We also find evidence for a thin dehydrated PEO layer (≤1 nm) close to the micellar core. The results provide substantial insight into the interplay between crystallinity and molecular packing in confinement and the resulting overall micellar shape.
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Murray, J. Sam; Nishimura, Tomohiro; Finch, Sara J.; Rhodes, Lesley J.; Puddick, Jonathan & Harwood, D. Tim
[Show all 13 contributors for this article]
(2020).
The role of 44-methylgambierone in ciguatera fish poisoning: Acute toxicity, production by marine microalgae and its potential as a biomarker for Gambierdiscus spp.
Harmful Algae.
ISSN 1568-9883.
97.
doi:
10.1016/j.hal.2020.101853.
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Ciguatera fish poisoning (CFP) is prevalent around the tropical and sub-tropical latitudes of the world and impacts many Pacific island communities intrinsically linked to the reef system for sustenance and trade. While the genus Gambierdiscus has been linked with CFP, it is commonly found on tropical reef systems in microalgal assemblages with other genera of toxin-producing, epiphytic and/or benthic dinoflagellates – Amphidinium, Coolia, Fukuyoa, Ostreopsis and Prorocentrum. Identifying a biomarker compound that can be used for the early detection of Gambierdiscus blooms, specifically in a mixed microalgal community, is paramount in enabling the development of management and mitigation strategies. Following on from the recent structural elucidation of 44-methylgambierone, its potential to contribute to CFP intoxication events and applicability as a biomarker compound for Gambierdiscus spp. was investigated. The acute toxicity of this secondary metabolite was determined by intraperitoneal injection using mice, which showed it to be of low toxicity, with an LD50 between 20 and 38 mg kg−1. The production of 44-methylgambierone by 252 marine microalgal isolates consisting of 90 species from 32 genera across seven classes, was assessed by liquid chromatography-tandem mass spectrometry. It was discovered that the production of this secondary metabolite was ubiquitous to the eight Gambierdiscus species tested, however not all isolates of G. carpenteri, and some species/isolates of Coolia and Fukuyoa.
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Foss, Amanda J.; Miles, Christopher Owen; Wilkins, Alistair Lawrence; Rise, Frode; Trovik, Kristian Wiedicke & Cieslik, Kamil
[Show all 7 contributors for this article]
(2020).
Analysis of total microcystins and nodularins by oxidative cleavage of their ADMAdda, DMAdda, and Adda moieties.
Analytica Chimica Acta: X.
6.
doi:
10.1016/j.acax.2020.100060.
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Microcystins (MCs) and nodularins (NODs) exhibit high structural variability, including modifications of the Adda (3S-amino-9S-methoxy-2S,6,8S-trimethyl-10-phenyldeca-4E,6E-dienoic acid) moiety. Variations include 9-O-desmethylAdda (DMAdda) and 9-O-acetylDMAdda (ADMAdda) which, unless targeted, may go undetected. Therefore, reference standards were prepared of [ADMAdda5]MCs and [DMAdda5]MCs, which were analyzed using multiple approaches. The cross-reactivities of the [DMAdda5]- and [ADMAdda5]MC standards were similar to that of MC-LR when analyzed with a protein phosphatase 2A (PP2A) inhibition assay, but were <0.25% when analyzed with an Adda enzyme-linked immunosorbent assay (ELISA). Oxidative cleavage experiments identified compounds that could be used in the analysis of total MCs/NODs in a similar fashion to the 2R-methyl-3S-methoxy-4-phenylbutanoic acid (MMPB) technique. Products from oxidative cleavage of both the 4,5- and 6,7-ene of Adda, DMAdda and ADMAdda were observed, and three oxidation products, one from each Adda variant, were chosen for analysis and applied to three field samples and a Nostoc culture. Results from the oxidative cleavage method for total Adda, DMAdda, and ADMAdda were similar to those from the Adda-ELISA, PP2A inhibition, and LC-MS/MS analyses, except for the Nostoc culture where the Adda-ELISA greatly underestimated microcystin levels. This oxidative cleavage method can be used for routine analysis of field samples and to assess the presence of the rarely reported, but toxic, DMAdda/ADMAdda-containing MCs and NODs.
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Kildahl-Andersen, Geir; Gjerlaug-Enger, Eli; Rise, Frode; Haug, Anna & Egelandsdal, Bjørg
(2020).
Quantification of Fatty Acids and their Regioisomeric Distribution in Triacylglycerols from Porcine and Bovine Sources Using 13C NMR Spectroscopy.
Lipids.
ISSN 0024-4201.
doi:
10.1002/lipd.12277.
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The uptake of specific fatty acids in humans is dependent on their position on the glycerol backbone. There is a great interest in methods that can access this information fast and accurately. By way of high-resolution NMR, we have analyzed TAG extracted from pig and beef tissues and obtained quantitative data for the composition and regioisomeric distribution of all major unsaturated fatty acids usually found in these source materials, using a combination of manual integration and deconvolution of 13C NMR spectra. In addition, we have developed a method for determining composition and regioisomeric distribution of the two main saturated fatty acids found in pork (16:0, 18:0). The results are discussed in relation to species-specific genetic characteristics of fatty acid and TAG biosynthesis. The developed method could support decisions related to breeding for desired fatty acid profiles, and stimulate further methodology developments using high field NMR.
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Jakubec, Martin; Totland, Christian; Rise, Frode; Chamgordani, Elahe Jafari; Paulsen, Britt & Maes, Louis
[Show all 9 contributors for this article]
(2020).
Bioactive metabolites of marine origin have unusual effects on model membrane systems.
Marine Drugs.
18(2),
p. 1–11.
doi:
10.3390/md18020125.
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Marine sponges and soft corals have yielded novel compounds with antineoplastic and antimicrobial activities. Their mechanisms of action are poorly understood, and in most cases, little relevant experimental evidence is available on this topic. In the present study, we investigated whether agelasine D (compound 1) and three agelasine analogs (compound 2–4) as well as malonganenone J (compound 5), affect the physical properties of a simple lipid model system, consisting of dioleoylphospahtidylcholine and dioleoylphosphatidylethanolamine. The data indicated that all the tested compounds increased stored curvature elastic stress, and therefore, tend to deform the bilayer which occurs without a reduction in the packing stress of the hexagonal phase. Furthermore, lower concentrations (1%) appear to have a more pronounced effect than higher ones (5–10%). For compounds 4 and 5, this effect is also reflected in phospholipid headgroup mobility assessed using 31P chemical shift anisotropy (CSA) values of the lamellar phases. Among the compounds tested, compound 4 stands out with respect to its effects on the membrane model systems, which matches its efficacy against a broad spectrum of pathogens. Future work that aims to increase the pharmacological usefulness of these compounds could benefit from taking into account the compound effects on the fluid lamellar phase at low concentrations
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Samuelsen, Anne Berit C.; Rise, Frode; Wilkins, Alistair L.; Teveleva, Lioubov; Nyman, Anna Armika Tussilago & Aachmann, Finn Lillelund
(2019).
The edible mushroom Albatrellus ovinus contains a α-L-fuco-α-D-galactan, α-D-glucan, a branched (1→6)-β-D-glucan and a branched (1→3)-β-D-glucan.
Carbohydrate Research.
ISSN 0008-6215.
471,
p. 28–38.
doi:
10.1016/j.carres.2018.10.012.
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Albatrellus ovinus, the sheep polypore, is a large, dense mushroom being rich in cell wall material.
Polysaccharides were isolated by sequential extraction, enzymatic treatment and analyzed with respect to
monosaccharide composition, glycosidic linkages by methylation and GC-MS as well as NMR spectroscopy. A
fucogalactan composed of an (1→6)-α-D-galactan backbone with single α-L-Fucp residues attached at O-2 was
identified in the hot water extract obtained after treatment with a protease and size exclusion chromatography.
Both the hot water extract and the hot alkali extract contained an (1→4)-α-D-glucan whereas β-D-glucans were
mainly present in the latter. Structural analysis suggested the presence of two different β-D-glucan backbone
structures; a (1→6)-linked β-D-glucan with single β-D-Glcp residues at O-3 and also a (1→3)-linked β-D-glucan
with branches in O-6. In addition there were identified short (1→2)-linked β-D-xylan and (1→3)-α-D-mannan
chains.
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Pang, Di-Jiang; Huang, Chao; Chen, Mei-Ling; Chen, Yu-Long; Fu, Yu-Ping & Paulsen, Berit Smestad
[Show all 16 contributors for this article]
(2019).
Characterization of Inulin-Type Fructan from Platycodon grandiflorus and Study on Its Prebiotic and Immunomodulating Activity.
Molecules.
ISSN 1431-5157.
24(7).
doi:
10.3390/molecules24071199.
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Platycodon grandiflorus is a plant widely used in traditional Chinese medicine, of which polysaccharides are reported to be the main components responsible for its bio-functions. In this work, the inulin-type fructan (PGF) was obtained by DEAE anion exchange chromatography from the water extracted from P. grandifloras. Characterization was performed with methanolysis, methylation, and NMR and the results showed that PGF is a β-(2-1) linked fructan, with terminal glucose and with a degree of polymerization of 2–10. In order to study its biofunctions, the prebiotic and immunomodulation properties were assayed. We found that PGF exhibited good prebiotic activity, as shown by a promotion on six strains of lactobacillus proliferation. Additionally, the PGF also displayed direct immunomodulation on intestinal epithelial cells and stimulated the expressions of anti-inflammatory factors. These results indicated that the inulin from P. grandiflorus is a potential natural source of prebiotics as well as a potential intestinal immunomodulator, which will be valuable for further studies and new applications.
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Murray, J Sam; Selwood, Andrew I.; Harwood, D Tim; Ginkel, Roel van; Puddick, Jonathan & Rhodes, Lesley L
[Show all 8 contributors for this article]
(2019).
44-Methylgambierone, a new gambierone analogue isolated from Gambierdiscus australes.
Tetrahedron Letters.
ISSN 0040-4039.
60(8),
p. 621–625.
doi:
10.1016/j.tetlet.2019.01.043.
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A new analogue of gambierone, 44-methylgambierone, was isolated from the benthic dinoflagellate Gambierdiscus australes collected from Raoul Island (Rangitahua/Kermadec Islands). This molecule has been previously reported as maitotoxin-3. The structure of 44-methylgambierone was elucidated using 1D- and 2D-nuclear magnetic resonance spectroscopy and mass spectrometry techniques. The nine-ring polyether backbone (A–I) and functional groups (carbonyl, terminal diol, 1,3-diene and monosulphate) are the same for both compounds with the addition of an olefinic methyl group being the only modification in 44-methylgambierone.
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Kenton, Nathaniel; Adu-Amprawum, Daniel; Okumu, Anthony A.; Zhang, Zhingao; Chen, Yong & Nguyen, Son
[Show all 14 contributors for this article]
(2018).
Total Synthesis of (6R,10R,13R,14R,16R,17R,19S,20R,21R,24S, 25S,28S,30S,32R,33R,34R,36S,37S,39R)-Azaspiracid-3 Reveals Non-Identity with the Natural Product.
Angewandte Chemie International Edition.
ISSN 1433-7851.
57(3),
p. 805–809.
doi:
10.1002/anie.201711006.
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Kenton, Nathaniel T.; Adu-Ampratwum, Daniel; Okumu, Anthony A.; McCarron, Pearse; Kilcoyne, Jane & Rise, Frode
[Show all 9 contributors for this article]
(2018).
Stereochemical Definition of the Natural Product (6R,10R,13R, 14R,16R,17R,19S,20S,21R,24S,25S,28S,30S,32R,33R,34R,36S,37S,39R)-Azaspiracid-3 by Total Synthesis and Comparative Analyses.
Angewandte Chemie International Edition.
ISSN 1433-7851.
57(3),
p. 810–813.
doi:
10.1002/anie.201711008.
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Morland, Cecilie; Frøland, Anne-Sofie; Nguyen, Mi Mong Tran; Storm-Mathisen, Jon; Gundersen, Vidar & Rise, Frode
[Show all 7 contributors for this article]
(2018).
Propionate enters GABAergic neurons, inhibits GABA transaminase, causes GABA accumulation and lethargy in a model of propionic acidemia.
Biochemical Journal.
ISSN 0264-6021.
doi:
10.1042/BCJ20170814.
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Propionic acidemia is the accumulation of propionate in blood due to dysfunction of propionyl-CoA carboxylase. The condition causes lethargy and striatal degeneration with motor impairment in humans. How propionate exerts its toxic effect is unclear. Here, we show that intravenous administration of propionate causes dose-dependent propionate accumulation in the brain and transient lethargy in mice. Propionate, an inhibitor of histone deacetylase, entered GABAergic neurons, as could be seen from increased neuronal histone H4 acetylation in the striatum and neocortex. Propionate caused an increase in GABA (γ-amino butyric acid) levels in the brain, suggesting inhibition of GABA breakdown. In vitro propionate inhibited GABA transaminase with a Ki of ∼1 mmol/l. In isolated nerve endings, propionate caused increased release of GABA to the extracellular fluid. In vivo, propionate reduced cerebral glucose metabolism in both striatum and neocortex. We conclude that propionate-induced inhibition of GABA transaminase causes accumulation of GABA in the brain, leading to increased extracellular GABA concentration, which inhibits neuronal activity and causes lethargy. Propionate-mediated inhibition of neuronal GABA transaminase, an enzyme of the inner mitochondrial membrane, indicates entry of propionate into neuronal mitochondria. However, previous work has shown that neurons are unable to metabolize propionate oxidatively, leading us to conclude that propionyl-CoA synthetase is probably absent from neuronal mitochondria. Propionate-induced inhibition of energy metabolism in GABAergic neurons may render the striatum, in which >90% of the neurons are GABAergic, particularly vulnerable to degeneration in propionic acidemia.
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Furse, Samuel Robert; Jakubec, Martin; Rise, Frode; Williams, Huw E.; Rees, Catherine E.D. & Halskau, Øyvind
(2017).
Evidence that Listeria innocua modulates its membrane's stored curvature elastic stress, but not fluidity, through the cell cycle.
Scientific Reports.
7:8012,
p. 1–11.
doi:
10.1038/s41598-017-06855-z.
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This paper reports that the abundances of endogenous cardiolipin and phosphatidylethanolamine halve during elongation of the Gram-positive bacterium Listeria innocua. The lyotropic phase behaviour of model lipid systems that describe these modulations in lipid composition indicate that the average stored curvature elastic stress of the membrane is reduced on elongation of the cell, while the fluidity appears to be maintained. These findings suggest that phospholipid metabolism is linked to the cell cycle and that changes in membrane composition can facilitate passage to the succeding stage of the cell cycle. This therefore suggests a means by which bacteria can manage the physical properties of their membranes through the cell cycle.
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Wold, Christian Winther; Kjeldsen, Christian; Corthay, Alexandre; Rise, Frode; Christensen, Bjørn E. & Duus, Jens Øllgaard
[Show all 7 contributors for this article]
(2017).
Structural characterization of bioactive heteropolysaccharides from the
medicinal fungus Inonotus obliquus (Chaga).
Carbohydrate Polymers.
ISSN 0144-8617.
185,
p. 27–40.
doi:
10.1016/j.carbpol.2017.12.041.
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The aim of this paper was to perform a comprehensive characterization of polysaccharides isolated from the interior (IOI) and exterior (IOE) parts of the fungus Inonotus obliquus. Pre-extraction with DCM and MeOH, followed by water and alkali extraction and ethanol precipitation gave two water extracts and two alkali extracts. Neutral and acidic polysaccharide fractions were obtained after anion-exchange chromatography of the water extracts. The neutral polysaccharides (60–73 kDa) were heterogeneous and branched and consisted of a (1 → 3)-linked β-Glc backbone with (1 → 6)-linked kinks in the chain at approximately every fifth residue, with branches of (1 → 6)-linked β-Glc in addition to substantial amounts of (1 → 6)-linked α-Gal with 3-O-methylation at about every third Gal residue. The acidic polysaccharide fractions (10–31 kDa) showed similar structural motifs as the neutral fractions differing mainly by the presence of (1 → 4)-linked α-GalA and α-GlcA. β-Xyl, α-Man and α-Rha were also present in varying amounts in all fractions. No major structural differences between the IOI and IOE fractions were observed. An alkaline polysaccharide fraction (>450 kDa) was obtained from the IOI alkali extract, and consisted mainly of (1 → 3)- and (1 → 6)-linked β-Glc and (1 → 4)-linked β-Xyl. Several of the fractions showed in vitro immunomodulatory effect by increasing NO production in the murine macrophage and dendritic cell lines J774.A1 and D2SC/1. Most fractions managed to increase NO production only at the highest concentration tested (100 μg/ml), while the neutral fraction IOE-WN activated potent NO production at 10 μg/ml and was considered the most promising immunomodulating fraction in this study.
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Nytoft, Hans Peter; Kildahl-Andersen, Geir & Rise, Frode
(2016).
Unusual hexacyclic oleananes in Late
Cretaceous/Tertiary terrigenous oils: NMR characterisation of the major hexacyclic oleanane in Niger Delta oil.
Organic Geochemistry.
ISSN 0146-6380.
101,
p. 196–206.
doi:
10.1016/j.orggeochem.2016.08.016.
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Stanic, Ana; Uhlig, Silvio; Solhaug, Anita; Rise, Frode; Wilkins, Alistair Lawrence & Miles, Christopher Owen
(2016).
Preparation and Characterization of Cysteine Adducts of Deoxynivalenol.
Journal of Agricultural and Food Chemistry.
ISSN 0021-8561.
64(23),
p. 4777–4785.
doi:
10.1021/acs.jafc.6b01158.
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Nytoft, H. Peter; Vukovic, Nikola S.; Kildahl-Andersen, Geir; Rise, Frode; Zivotic, Dragana R. & Stojanovic, Ksenija A
(2016).
Identification of a Novel Series of Benzohopanes and Their Geochemical Significance.
Energy & Fuels.
ISSN 0887-0624.
30(7),
p. 5563–5575.
doi:
10.1021/acs.energyfuels.6b00799.
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Nyman, Anna Armika Tussilago; Aachmann, Finn Lillelund; Rise, Frode; Ballance, Simon & Samuelsen, Anne Berit C.
(2016).
Structural characterization of a branched (1 → 6)-α-mannan and β-glucans isolated from the fruiting bodies of Cantharellus cibarius.
Carbohydrate Polymers.
ISSN 0144-8617.
146,
p. 197–207.
doi:
10.1016/j.carbpol.2016.03.052.
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A comprehensive characterization of polysaccharides from the chanterelle was performed. Experiments included both linkage analysis by methylation and GC–MS, monosaccharide composition analysis by methanolysis, SEC-MALLS and several NMR experiments including COSY, HSQC, TOCSY, HSQC-TOCSY, NOESY, and HMBC. A 671 kDa (1 → 6)-linked α-d-mannan with single and short (1 → 2)-linked side chains (WCcF1b) was isolated from the hot water extract, after protease treatment and fractionation by size exclusion chromatography. The hot 1 M NaOH extract contained two types of β-glucan; a water soluble (1 → 6)-linked β-d-glucan with single and short (1 → 3)-linked β-glucan side chains (ACcSw) and a less branched (1 → 3)-linked β-d-glucan (ACcIw/ACcId), proposed to contain short side chains in O-4. Chemical shifts assignments of the α-mannan and β-glucan are presented as well as chemical shift values obtained from a (1 → 6)/(1 → 3)-β-d-glucan derived from Saccharomyces cerevisiae which was used as reference.
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Stanic, Ana; Uhlig, Silvio; Sandvik, Morten; Rise, Frode; Wilkins, Alistair Lawrence & Miles, Christopher Owen
(2016).
Characterization of Deoxynivalenol-Glutathione Conjugates Using Nuclear Magnetic Resonance Spectroscopy and Liquid Chromatography-High-Resolution Mass Spectrometry.
Journal of Agricultural and Food Chemistry.
ISSN 0021-8561.
64(36),
p. 6903–6910.
doi:
10.1021/acs.jafc.6b02853.
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Stanic, Ana; Uhlig, Silvio; Solhaug, Anita; Rise, Frode; Wilkins, Alistair Lawrence & Miles, Christopher Owen
(2015).
Nucleophilic Addition of Thiols to Deoxynivalenol.
Journal of Agricultural and Food Chemistry.
ISSN 0021-8561.
63(34),
p. 7556–7566.
doi:
10.1021/acs.jafc.5b02864.
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Conjugation of deoxynivalenol (DON) with sulfur compounds is recognized as a significant reaction pathway, and putative DON–glutathione (DON–GSH) conjugates have been reported in planta. To understand and control the reaction of trichothecenes with biologically important thiols, we studied the reaction of DON, T-2 tetraol, and de-epoxy-DON with a range of model thiols. Reaction conditions were optimized for DON with 2-mercaptoethanol. Major reaction products were identified using HRMS and NMR spectroscopy. The results indicate that thiols react reversibly with the double bond (Michael addition) and irreversibly with the epoxide group in trichothecenes. These reactions occurred at different rates, and multiple isomers were produced including diconjugated forms. LC-MS analyses indicated that glutathione and cysteine reacted with DON in a similar manner to the model thiols. In contrast to DON, none of the tested mercaptoethanol adducts displayed toxicity in human monocytes or induced pro-inflammatory cytokines in human macrophages.
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Kilcoyne, Jane; Nulty, Ciara; Jauffrais, Thierry; McCarron, Pearse; Herve, Fabienne & Foley, Barry
[Show all 12 contributors for this article]
(2014).
Isolation, structure elucidation, relative LC-MS response, and in vitro toxicity of azaspiracids from the dinoflagellate azadinium spinosum.
Journal of natural products.
ISSN 0163-3864.
77(11),
p. 2465–2474.
doi:
10.1021/np500555k.
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Kilcoyne, Jane; McCarron, Pearse; Twiner, Michael J.; Nulty, Ciara; Crain, Sheila & Quilliam, Michael A.
[Show all 9 contributors for this article]
(2014).
Epimers of azaspiracids: Isolation, structural elucidation, relative LC-MS response, and in vitro toxicity of 37-epi-azaspiracid-1.
Chemical Research in Toxicology.
ISSN 0893-228X.
27(4),
p. 587–600.
doi:
10.1021/tx400434b.
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Nytoft, Hans Peter; Kildahl-Andersen, Geir; Knudsen, Tatjana Šolević; Stojanović, Ksenija & Rise, Frode
(2014).
Compound "J" in Late Cretaceous/Tertiary terrigenous oils revisited: Structure elucidation of a rearranged oleanane coeluting on GC with 18β(H)-oleanane.
Organic Geochemistry.
ISSN 0146-6380.
77,
p. 89–95.
doi:
10.1016/j.orggeochem.2014.09.010.
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Langseth, Eirin; Nova, Ainara; Tråseth, Eline Aasen; Rise, Frode; Øien, Sigurd & Heyn, Richard H
[Show all 7 contributors for this article]
(2014).
A gold exchange: A mechanistic study of a reversible, formal ethylene insertion into a gold(III)-oxygen bond.
Journal of the American Chemical Society.
ISSN 0002-7863.
136(28),
p. 10104–10115.
doi:
10.1021/ja504554u.
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The Au(III) complex Au(OAcF)2(tpy) (1, OAcF = OCOCF3; tpy = 2-p-tolylpyridine) undergoes reversible dissociation of the OAcF ligand trans to C, as seen by 19F NMR. In dichloromethane or trifluoroacetic acid (TFA), the reaction between 1 and ethylene produces Au(OAcF)(CH2CH2OAcF)(tpy) (2). The reaction is a formal insertion of the olefin into the Au–O bond trans to N. In TFA this reaction occurs in less than 5 min at ambient temperature, while 1 day is required in dichloromethane. In trifluoroethanol (TFE), Au(OAcF)(CH2CH2OCH2CF3)(tpy) (3) is formed as the major product. Both 2 and 3 have been characterized by X-ray crystallography. In TFA/TFE mixtures, 2 and 3 are in equilibrium with a slight thermodynamic preference for 2 over 3. Exposure of 2 to ethylene-d4 in TFA caused exchange of ethylene-d4 for ethylene at room temperature. The reaction of 1 with cis-1,2-dideuterioethylene furnished Au(OAcF)(threo-CHDCHDOAcF)(tpy), consistent with an overall anti addition to ethylene. DFT(PBE0-D3) calculations indicate that the first step of the formal insertion is an associative substitution of the OAcF trans to N by ethylene. Addition of free –OAcF to coordinated ethylene furnishes 2. While substitution of OAcF by ethylene trans to C has a lower barrier, the kinetic and thermodynamic preference of 2 over the isomer with CH2CH2OAcF trans to C accounts for the selective formation of 2. The DFT calculations suggest that the higher reaction rates observed in TFA and TFE compared with CH2Cl2 arise from stabilization of the –OAcF anion lost during the first reaction step.
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Miles, Christopher; Sandvik, Morten; Nonga, Hezron Emmanuel; Rundberget, Thomas; Wilkins, Alistair Lawrence & Rise, Frode
[Show all 7 contributors for this article]
(2013).
Identification of microcystins in a Lake Victoria cyanobacterial bloom using LC-MS with thiol derivatization.
Toxicon.
ISSN 0041-0101.
70,
p. 21–31.
doi:
10.1016/j.toxicon.2013.03.016.
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Microcystins are cyclic heptapeptides from cyanobacteria which are responsible for poisonings of livestock and humans. Cyanobacteria also produce a range of peptides and other compounds that can result in complex chromatograms when samples are analysed by LC–MS. Thiol derivatization of the α,β-unsaturated amide present in most microcystins was recently shown to simplify analysis of LC–MS chromatograms of a Microcystis culture, making it easier to identify peaks corresponding to microcystins in complex mixtures. This method was applied to analysis of extracts taken from a natural cyanobacteria bloom in Mwanza Gulf, Lake Victoria, Tanzania, in 2010, revealing the presence of numerous putative microcystin analogues in the sample. Results were verified using LC–MS2, LC–MS/MS with precursor-ion scanning, and LC–HRMS, leading to identification of 8 major and 17 minor microcystins in the sample, including analogues of microcystin-RY, -RL and -RA. Microcystin-YR (2), -RR (3), and -RY (9) were isolated from bloom material from Lake Victoria, and the structure of 9 was confirmed by NMR spectroscopic analysis and NMR spectral comparison with 2 and 3. Confirmation of the structure of MC-RY (9) facilitated detailed analysis of its MS2 spectrum, thereby supporting the structures of related analogues tentatively established on the basis of MS analyses.
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Puddick, Jonathan; Prinsep, M. R.; Wood, Susanna A.; Miles, Christopher Owen; Rise, Frode & Cary, S. Craig
[Show all 8 contributors for this article]
(2013).
Structural characterization of new microcystins containing tryptophan and oxidized tryptophan residues.
Marine Drugs.
11(8),
p. 3025–3045.
doi:
10.3390/md11083025.
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Microcystins are cyclic peptides produced by cyanobacteria, which can be harmful to humans and animals when ingested. Eight of the (more than) 90 microcystin variants presently characterized, contain the amino acid tryptophan. The well-researched oxidation products of tryptophan; kynurenine, oxindolylalanine, and N-formylkynurenine, have been previously identified in intact polypeptides but microcystin congeners containing oxidized tryptophan moieties have not been reported. Liquid
chromatography-tandem mass spectrometric analysis of an extract of Microcystis CAWBG11 led to the tentative identification of two new tryptophan-containing microcystins (MC WAba and MC-WL), as well as eight other microcystin analogs containing kynurenine, oxindolylalanine and N formylkynurenine (Nfk). Investigation of one of these congeners (MC NfkA) by nuclear magnetic resonance spectroscopy was used to verify the presence of Nfk in the microcystin. Liquid chromatography-mass spectrometry analysis of a tryptophan oxidation experiment demonstrated that
tryptophan-containing microcystins could be converted into oxidized tryptophan analogs and that low levels of oxidized tryptophan congeners were present intracellularly in CAWBG11. MC-NfkR and MC-LNfk were detected in standards of MC-WR and MC-LW, indicating that care during storage of tryptophan-containing microcystins is required.
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Miles, Christopher; Sandvik, Morten; Nonga, Hezron Emmanuel; Rundberget, Thomas; Wilkins, Alistair Lawrence & Rise, Frode
[Show all 7 contributors for this article]
(2012).
Thiol Derivatization for LC-MS Identification of Microcystins in Complex Matrices.
Environmental Science and Technology.
ISSN 0013-936X.
46(16),
p. 8937–8944.
doi:
10.1021/es301808h.
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Microcystins are a group of cyclic heptapeptides originating from cyanobacteria. Cyanobacteria also produce a range of peptides and other compounds that can result in complex chromatograms when samples are analyzed by LC-MS. Derivatization with appropriate thiols (e.g., mercaptoethanol) of the olefin in the α,β-unsaturated amide present in most microcystins was shown to simplify analysis of LC-MS chromatograms of sample extracts, making it much easier to identify peaks corresponding to candidate microcystins. Furthermore, interpretation of MS2 spectra was facilitated by addition of the mass associated with the thiol to the α,β-unsaturated amide of microcystins. Cyanotoxins containing Mdha or Dha reacted readily with thiols, whereas Mser, Ser, Mdhb, and thiol-derivatives of Mdha or Dha did not react under the conditions used. This approach therefore provides a convenient LC-MS method to obtain evidence for the presence of Mdha or Dha and can likely be used to differentiate between the isobaric amino acids Mdha and Dhb in candidate cyanotoxin peaks. When O-(2-mercaptoethyl)-O′-methyl-hexa(ethylene glycol) (MEMHEG) (Mwt. 356) was used as the thiol, the resulting derivatives eluted in an LC-MS mass window that was largely free of interferences. This approach simplifies detection of candidate microcystin analogues even in the presence of complex mixtures of coeluting components. The method was used for qualitative analysis of a Microcystis aeruginosa culture from Lake Naivasha, Kenya, and the results were verified using precursor-ion scanning and high-resolution mass spectrometry.
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Sachse, Daniel; Sletner, Line; Mørkrid, Kjersti; Jenum, Anne Karen; Birkeland, Kåre I. & Rise, Frode
[Show all 8 contributors for this article]
(2012).
Metabolic Changes in Urine during and after Pregnancy in a Large, Multiethnic Population-Based Cohort Study of Gestational Diabetes.
PLOS ONE.
7(12).
doi:
10.1371/journal.pone.0052399.
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This study aims to identify novel markers for gestational diabetes (GDM) in the biochemical profile of maternal urine using NMR metabolomics. It also catalogs the general effects of pregnancy and delivery on the urine profile. Urine samples were collected at three time points (visit V1: gestational week 8–20; V2: week 28±2; V3:10–16 weeks post partum) from participants in the STORK Groruddalen program, a prospective, multiethnic cohort study of 823 healthy, pregnant women in Oslo, Norway, and analyzed using 1H-NMR spectroscopy. Metabolites were identified and quantified where possible. PCA, PLS-DA and univariate statistics were applied and found substantial differences between the time points, dominated by a steady increase of urinary lactose concentrations, and an increase during pregnancy and subsequent dramatic reduction of several unidentified NMR signals between 0.5 and 1.1 ppm. Multivariate methods could not reliably identify GDM cases based on the WHO or graded criteria based on IADPSG definitions, indicating that the pattern of urinary metabolites above micromolar concentrations is not influenced strongly and consistently enough by the disease. However, univariate analysis suggests elevated mean citrate concentrations with increasing hyperglycemia. Multivariate classification with respect to ethnic background produced weak but statistically significant models. These results suggest that although NMR-based metabolomics can monitor changes in the urinary excretion profile of pregnant women, it may not be a prudent choice for the study of GDM.
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Uhlig, Silvio; Busman, Mark; Shane, Deborah S; Rønning, Helene; Rise, Frode & Proctor, Robert
(2012).
Identification of Early Fumonisin Biosynthetic Intermediates by Inactivation of the FUM6 Gene in Fusarium verticillioides.
Journal of Agricultural and Food Chemistry.
ISSN 0021-8561.
60(41),
p. 10293–10301.
doi:
10.1021/jf302967b.
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Moldes-Anaya, Angel; Rundberget, Thomas; Uhlig, Silvio; Rise, Frode & Wilkins, Alistair Lawrence
(2011).
Isolation and structure elucidation of secopenitrem D, an indole alkaloid from Penicillium crustosum Thom.
Toxicon.
ISSN 0041-0101.
57(2),
p. 259–265.
doi:
10.1016/j.toxicon.2010.11.020.
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Chemical investigation of three isolates of Penicillium crustosum Thom cultures, one of which was derived from a recent dog poisoning investigation, has led to the isolation and structure elucidation of secopenitrem D (1). Penitrems A-F and roquefortine C were also present in the isolates analyzed. The structure of 1 was unambiguously assigned based on extensive 1D and 2D-NMR spectroscopic experiments, MS-aided structural studies and by comparison with structurally related congeners. Secopenitrem D lacks the C-16-C-18 ether linkage present in penitrems A-F.
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Wilson, Steven Ray Haakon; Strand, Martin Frank; Krapp, Andreas; Rise, Frode; Petersen, Dirk & Krauss, Stefan
(2010).
Hedgehog antagonist cyclopamine isomerizes to less potent forms when acidified.
Journal of Pharmaceutical and Biomedical Analysis.
ISSN 0731-7085.
52(5),
p. 707–713.
doi:
10.1016/j.jpba.2010.02.017.
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Tutturen, Astrid Elisabeth Voorham; Holm, Anders; Jørgensen, Marit; Stadtmüller, Patricia; Rise, Frode & Fleckenstein, Burkhard
(2010).
A technique for the specific enrichment of citrulline-containing peptides.
Analytical Biochemistry.
ISSN 0003-2697.
403(1-2),
p. 43–51.
doi:
10.1016/j.ab.2010.04.012.
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Gundersen, Lise-Lotte; Rise, Frode; Undheim, Kjell; Aguilar, E. & Garcia-Garcia, P
(2009).
Titanium(IV) Chloride.
In Paquette, Leo A. (Eds.),
Encyclopedia of Reagents for Organic Synthesis. 2. Ed.
John Wiley & Sons.
ISSN 9780470017548.
p. 9526–9552.
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Gundersen, Lise-Lotte; Rise, Frode & Undheim, Kjell
(2009).
Methylzirconium Tributoxide.
In Paquette, Leo A. (Eds.),
Encyclopedia of Reagents for Organic Synthesis. 2. Ed.
John Wiley & Sons.
ISSN 9780470017548.
p. 7161–7162.
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Gundersen, Lise-Lotte; Rise, Frode & Undheim, Kjell
(2009).
Zirconium(III) Chloride.
In Paquette, Leo A. (Eds.),
Encyclopedia of Reagents for Organic Synthesis. 2. Ed.
John Wiley & Sons.
ISSN 9780470017548.
p. 10965–10965.
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Gundersen, Lise-Lotte; Rise, Frode; Undheim, Kjell & Mendez-Andino, J.
(2009).
Titanium(III) Chloride.
In Paquette, Leo A. (Eds.),
Encyclopedia of Reagents for Organic Synthesis. 2. Ed.
John Wiley & Sons.
ISSN 9780470017548.
p. 9523–9526.
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Gorbitz, Carl Henrik & Rise, Frode
(2008).
Template-directed supramolecular assembly of a new type of nanoporous peptide-based material.
Journal of Peptide Science.
ISSN 1075-2617.
14(2),
p. 210–216.
doi:
10.1002/psc.985.
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Dipeptides with two hydrophobic residues are known to often form crystals with hydrophobic or hydrophilic channels. One of the exceptions is Leu-Ile, which has been previously shown to crystallize as a nonporous 0.75 hydrate in the hexagonal space group P61 with Z = 4. We have now found that in the presence of D-Leu, a second pseudopolymorph of the dipeptide is formed. The crystal structure has hydrophilic, water-filled channels with an irregular cross section of approximately 5.5 × 3.5 Å and constitutes the first example of a crystal packing arrangement where the direction of the channels is perpendicular to the direction of hydrophobic stacking of side chains rather than parallel as in all other porous peptide-based materials.
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Mmatli, Edward M; Malerød, Helle; Wilson, Steven Ray Haakon; Abegaz, Berhanu m; Greibrokk, Tyge & Lundanes, Elsa
[Show all 9 contributors for this article]
(2007).
Identification of major metal complexing compounds in Blepharis aspera.
Analytica Chimica Acta.
ISSN 0003-2670.
597(1),
p. 24–31.
doi:
10.1016/j.aca.2007.06.042.
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Verbascoside and isoverbascoside, present at 0.7% and 0.2% (w/w dryweight), were identified to be major compounds that could contribute to the metal complexation in Blepharis aspera collected in Botswana, Africa. The metallophyte B. aspera has high ability to cope with a high level of metal accumulation. The presence of metal complexing compounds and/or antioxidants can prevent oxidative reactions in lipids, proteins and DNA that take place due to the metal accumulation. On-line liquid chromatography–solid phase extraction–nuclear magnetic resonance (LC–SPE–NMR) was applied for the identification, while electrospray-mass spectrometry (ESI-MS) and UV-vis spectroscopy was used to assess whether these compounds can complex with metals. It was found that verbascoside and isoverbascoside may form complexes with nickel, iron (verbascoside only) and copper. Thus, the presence of verbascoside and isoverbascoside can explain the survival of B. aspera in mineral-rich areas.
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Nguyen, Nga H. T.; Morland, C; Gonzales, Susana Villa; Rise, Frode; Storm-Mathisen, Jon & Gundersen, Vidar
[Show all 7 contributors for this article]
(2007).
Propionate increases neuronal histone acetylation, but is metabolized oxidatively by glia. Relevance for propionic acidemia.
Journal of Neurochemistry.
ISSN 0022-3042.
101(3),
p. 806–814.
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In propionic acidemia, propionate acts as a metabolic toxin in liver cells by accumulating in mitochondria as propionyl-CoA and its derivative, methylcitrate, two tricarboxylic acid cycle inhibitors. Little is known about the cerebral metabolism of propionate, although clinical effects of propionic acidemia are largely neurological. We found that propionate was metabolized oxidatively by glia: [3-(14)C]propionate injected into mouse striatum or cortex, gave a specific activity of glutamine that was 5-6 times that of glutamate, indicating metabolism in cells that express glutamine synthetase, i.e., glia. Further, cultured cerebellar astrocytes metabolized [3-(14)C]propionate; cultured neurons did not. However, both cultured cerebellar neurons and astrocytes took up [(3)H]propionate, and propionate exposure increased histone acetylation in cultured neurons and astrocytes as well as in hippocampal CA3 pyramidal neurons of wake mice. The inability of neurons to metabolize propionate may be due to lack of mitochondrial propionyl-CoA synthetase activity or transport of propionyl residues into mitochondria, as cultured neurons expressed propionyl-CoA carboxylase, a mitochondrial matrix enzyme, and oxidized isoleucine, which becomes converted into propionyl-CoA intramitochondrially. The glial metabolism of propionate suggests astrocytic vulnerability in propionic acidemia when intramitochondrial propionyl-CoA may accumulate. Propionic acidemia may alter both neuronal and glial gene expression by affecting histone acetylation.
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Nguyen, Nga Tran Huynh; Gonzalez, Susan Villa; Rise, Frode & Hassel, Bjørnar
(2007).
Cerebral metabolism of glucose and pyruvate in soman poisoning - A C-13 nuclear magnetic resonance spectroscopic study.
Neurotoxicology.
ISSN 0161-813X.
28(1),
p. 13–18.
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Organophosphates, such as the nerve gas soman, cause inhibition of acetylcholine esterase, accumulation of acetylcholine in synaptic clefts, and excessive activation of cholinergic receptors, causing central nervous symptoms such as tremor and seizures. Soman-poisoned animals have low brain levels of ATP, indicating that energy demand is greater than energy supply. We investigated whether soman poisoning is accompanied by an increased brain metab. of glucose, as can be inferred from the accumulation of radiolabeled 2-deoxyglucose found in previous studies, or whether soman poisoning entails impairment of cerebral energy metab. We performed 13C NMR spectroscopy on brain exts. from soman-poisoned mice (160 mg/kg; 1 LD50) that had been dosed with 13C-labeled glucose or pyruvate i.v. Formation of 13C-labeled glutamate, GABA and glutamine from [1-13C]glucose was reduced by approx. 30% in awake, soman-intoxicated animals, but formation of these amino acids from [3-13C]pyruvate was not different in soman-intoxicated animals and controls. These results suggest that soman intoxication entails inhibition of glycolysis, but not of tricarboxylic acid cycle activity in the brain. However, when brain metab. was depressed by a sedative dose of diazepam (5 mg/kg) soman intoxication caused increased metab. of 13C-labeled glucose. The latter finding shows that the soman-poisoned brain has a high energy requirement even during anticonvulsant therapy. We conclude that metabolic inhibition, as seen in awake, soman-intoxicated animals, may lower seizure threshold and contribute to soman-related neurodegeneration and lethality.
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Gundersen, LL; Charnock, Colin; Negussie, AH; Rise, F; Teklu, S & Weldegirma, Solomon Teklu
(2007).
Synthesis of indolizine derivatives with selective antibacterial activity against Mycobacterium tuberculosis.
European Journal of Pharmaceutical Sciences.
ISSN 0928-0987.
30.
doi:
10.1016/j.ejps.2006.09.006.
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Larsen, Kristofer; Petersen, Dirk; Wilkins, Alistair; Samdal, Ingunn; Sandvik, Morten & Rundberget, Thomas
[Show all 13 contributors for this article]
(2007).
Clarification of the C-35 stereochemistries of dinophysistoxin-1 and dinophysistoxin-2 and its consequences for binding to protein phosphatase.
Chemical Research in Toxicology.
ISSN 0893-228X.
20,
p. 868–875.
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Okadaic acid analogues are well known as protein phosphatase inhibitors and occur naturally in marine shellfish feeding on dinoflagellates of the genus Dinophysis, leading to diarrhetic shellfish poisoning of shellfish consumers. Knowledge of the correct structures for these toxins is important in understanding their toxicology, biochemistry, and biosynthesis. We have performed extensive NMR analyses on okadaic acid (1), dinophysistoxin-1 (DTX-1), and dinophysistoxin-2 (DTX-2) obtained from natural sources. Consequently, we were able to unambiguously deduce the stereochemistries at C-35 for DTX-1 and DTX-2 based on analysis of NMR coupling constants and NOE interactions. Our results revealed that DTX-2 (3) has a stereochemistry opposite to that of DTX-1 (2) at C-35. Molecular modeling of the docking of 1-3 with protein phosphatase-1 and protein phosphatase 2A (PP2A) suggested that the reduced affinity of DTX-2 for PP2A may be due to the newly defined stereochemistry at the 35-methyl group. The implications of these findings for biosynthesis and toxicology are discussed.
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Larsen, Kristofer; Petersen, Dirk; Wilkins, Alistair L.; Samdal, Ingunn; Sandvik, Morten & Rundberget, Thomas
[Show all 13 contributors for this article]
(2007).
Clarification of the C-35 Stereochemistries of Dinophysistoxin-1 and Dinophysistoxin-2 and Its Consequences for Binding to Protein Phosphatase.
Chemical Research in Toxicology.
ISSN 0893-228X.
20(6),
p. 868–875.
doi:
10.1021/tx700016m.
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Okadaic acid analogues are well known as protein phosphatase inhibitors and occur naturally in marine shellfish feeding on dinoflagellates of the genus Dinophysis, leading to diarrhetic shellfish poisoning of shellfish consumers. Knowledge of the correct structures for these toxins is important in understanding their toxicology, biochemistry, and biosynthesis. We have performed extensive NMR analyses on okadaic acid (1), dinophysistoxin-1 (DTX-1), and dinophysistoxin-2 (DTX-2) obtained from natural sources. Consequently, we were able to unambiguously deduce the stereochemistries at C-35 for DTX-1 and DTX-2 based on analysis of NMR coupling constants and NOE interactions. Our results revealed that DTX-2 (3) has a stereochemistry opposite to that of DTX-1 (2) at C-35. Molecular modeling of the docking of 1-3 with protein phosphatase-1 and protein phosphatase 2A (PP2A) suggested that the reduced affinity of DTX-2 for PP2A may be due to the newly defined stereochemistry at the 35-methyl group. The implications of these findings for biosynthesis and toxicology are discussed.
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Nguyen, Nga H. T.; Gonzalez, Susana Villa; Rise, Frode & Hassel, Bjørnar
(2007).
Cerebral metabolism of glucose and pyruvate in soman poisoning. A 13C nuclear magnetic resonance spectroscopic study.
Neurotoxicology.
ISSN 0161-813X.
doi:
10.1016/j.neuro.2006.09.007.
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Utenova, Bibigul; Malterud, Karl Egil & Rise, Frode
(2007).
Antioxidant activity of O-protected derivatives of (-)-epigallocatechin-3-gallate: inhibition of soybean and rabbit 15-lipoxygenases.
ARKIVOC.
ISSN 1551-7004.
ix,
p. 6–16.
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(-)-Epigallocatechin-3-gallate (EGCG) was protected at all eight phenolic groups as the methyl
ether or acetate, propionate or butyrate esters. The synthetic derivatives were examined for
antioxidant activities. The compounds were tested as potential diphenylpicrylhydrazyl (DPPH)
radical scavengers and as inhibitors of 15-lipoxygenase (15-LO) enzymes from soybeans and
rabbit reticulocytes. The O-protected EGCG derivatives were essentially inactive as DPPH
scavengers but showed profound inhibiting effects on both types of 15-LO, and the inhibitory
effects towards the two enzymes were significantly correlated. The O-protected EGCG
derivatives inhibited 15-LO more strongly that EGCG itself. EGCG and its O-protected
derivatives were also screened for antibacterial activity against M. tuberculosis.
Keywords: Flavonoids, (-)-Epigallocatechin-3-gallate, 15-Lipoxygenase, Radical scavenging
Introduction
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Wilson, Steven Ray Haakon; Greibrokk, Tyge; Lundanes, Elsa; Malerød, Helle; Petersen, Dirk & Rise, Frode
(2007).
An alternative LC-SPE-NMR design.
Journal of Separation Science.
ISSN 1615-9306.
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Aarnes, Halvor; Eriksen, Aud Else Berglen; Petersen, Dirk & Rise, Frode
(2007).
Accumulation of ammonium in Norway spruce (Picea abies) seedlings measured by in vivo 14N-NMR.
Journal of Experimental Botany.
ISSN 0022-0957.
58(5),
p. 929–934.
doi:
10.1093/jxb/erl247.
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http://jxb.oxfordjournals.org/cgi/content/abstract/erl247?
ijkey=y8vx24OpXL2qpyu&keytype=ref
14N-NMR and 31P-NMR have been used to monitor the in vivo pH in roots, stems, and needles from seedlings of Norway spruce, a typical ammonium-tolerant plant. The vacuolar and cytoplasmic pH measured by 31P-NMR was found to be c. pH 4.8 and 7.0, respectively, with no significant difference between plants growing with ammonium or nitrate as the N-source. The 1H-coupled 14NH resonance is pH-sensitive: at alkaline pH it is a narrow singlet line and below pH 4 it is an increasing multiplet line with five signals. The pH values in ammonium-containing compartments measured by 14N-NMR ranged from 3.7 to 3.9, notably lower than the estimated pH values of the Pi pools. This suggests that, in seedlings of Norway spruce, ammonium is stored in vacuoles with low pH possibly to protect the seedlings against the toxic effects of ammonium (NH) or ammonia (NH3). It was also found that concentrations of malate were 3–6 times higher in stems than in roots and needles, with nitrate-grown plants containing more malate than plants grown with ammonium.
Key words: Ammonium, cytoplasmic pH, in vivo 14N-NMR, in vivo 31P-NMR, malate, organic acids, Picea abies (L.) Karst, vacuolar pH
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Rundberget, Thomas; Sandvik, Morten; Larsen, Kristofer; Pizarro, G.M.; Reguera, Beatriz & Castberg, T
[Show all 11 contributors for this article]
(2007).
Extraction of microalgal toxins by large-scale pumping of seawater in Spain and Norway, and isolation of okadaic acid and dinophysistoxin-2.
Toxicon.
ISSN 0041-0101.
50(7),
p. 960–970.
doi:
10.1016/j.toxicon.2007.07.003.
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Marine biotoxins from microalgae can accumulate in shellfish and lead to poisoning of human consumers as well as fish, marine mammals and sea birds. Toxicological assessment of the toxins and development of analytical methods require large amounts of high-purity toxins and their metabolites. Although these toxins can be obtained in limited amounts from contaminated shellfish or from microalgal cultures, difficulties arise when the toxin-producing microalga is difficult to culture or its identity is not known. To circumvent this problem, we have developed a large-scale method for solid-phase extraction (SPE) of lipophilic biotoxins from natural microalgal blooms in seawater. To enhance subsequent purification of toxins adsorbed on the column, we included a filtration step to release the toxins from the cells while removing insoluble compounds and cellular debris. The efficacy of the method was illustrated by extraction and purification of okadaic acid and dinophysistoxin-2 from a high-density Dinophysis acuta bloom in Spain and from a mixed bloom containing low densities of D. acuta in Norway. Isolation of the toxins adsorbed on the SPE column was simple and efficient, and results obtained so far indicate that the method is potentially applicable to a wide range of microalgal toxins such as azaspiracids, pectenotoxins, spirolides and microcystins. The method should also be useful for harvesting toxins from large-scale microalgal cultures, and for bioprospecting for and isolation of bioactive natural products from marine and freshwater environments.
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Wilson, Steven Ray Haakon; Malerød, Helle; Petersen, Dirk; Rise, Frode; Lundanes, Elsa & Greibrokk, Tyge
(2007).
An alternative multiple-trapping LC-SPE-NMR system.
Journal of Separation Science.
ISSN 1615-9306.
30,
p. 322–328.
doi:
10.1002/jssc.200600238.
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Holm, Anders; Rise, Frode; Sessler, Nicole; Sollid, Ludvig Magne; Undheim, Kjell & Fleckenstein, Burkhard
(2006).
Specific modification of peptiode-bound citrulline residues.
Analytical Biochemistry.
ISSN 0003-2697.
352(1),
p. 68–76.
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Wilkins, Alistair L.; Rehman, Nils; Miles, Christopher O.; Torgersen, Trine; Rundberget, Thomas & Keogh, Myra
[Show all 9 contributors for this article]
(2006).
Identification of Fatty Acid Esters of Pectenotoxin-2 Seco Acid in Blue Mussels (Mytilus edulis) from Ireland.
Journal of Agricultural and Food Chemistry.
ISSN 0021-8561.
54(15),
p. 5672–5678.
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Spilsberg, Bjorn; Rise, Frode; Petersen, Dirk & Nissen-Meyer, Jon
(2006).
Thymidine secretion by hybridoma and myeloma cells.
Biochemical and Biophysical Research Communications - BBRC.
ISSN 0006-291X.
342,
p. 221–226.
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Teklu, Solomon; Gundersen, Lise-Lotte; Rise, Frode & Tilset, Mats
(2005).
Electrochemical Studies of Biologically Active Indolizines.
Tetrahedron.
ISSN 0040-4020.
65,
p. 4643–4656.
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Teklu, Solomon; Gundersen, Lise-Lotte; Larsen, Tove; Malterud, Karl Egil & Rise, Frode
(2005).
Indolizine 1-sulfonates as potent inhibitors of 15-lipoxygenase from soybeans.
Bioorganic & Medicinal Chemistry.
ISSN 0968-0896.
13,
p. 3127–3139.
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Bråthe, Anders; Gundersen, Lise-Lotte; Malterud, Karl Egil & Rise, Frode
(2005).
6-Substituted purines as inhibitors of 15-lipoxygenase; a structure-activity study.
Archiv der Pharmazie.
ISSN 0365-6233.
338,
p. 159–166.
doi:
10.1002/ardp.200400951.
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Rise, Frode; Gonzales, Susana Villa; Hassel, Bjørnar & Nguyen, Nga H. T.
(2005).
Brain metabolism of exogenous pyruvate.
Journal of Neurochemistry.
ISSN 0022-3042.
95(1),
p. 284–293.
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Bråthe, Anders; Gundersen, Lise-Lotte; Rise, Frode & Eriksen, Aud Else Berglen
(2005).
6-Cyclopropylpurines as Novel Potent Analogs of Cytokinins.
Journal of Plant Growth Regulation.
ISSN 0721-7595.
24,
p. 41–45.
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Abegaz, Berhanu m; Ngadjui, Bonaventure t; Folefoc, Gabriel n; Fotso, Serge; Ambassa, Pantaleon & Bezabih, Merhatibeb
[Show all 9 contributors for this article]
(2004).
Prenylated flavonoids, monoterpenoid furanocoumarins and other constituents from the twigs of Dorstenia elliptica (Moraceae).
Phytochemistry.
ISSN 0031-9422.
65,
p. 221–226.
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Gundersen, Lise-Lotte; Malterud, Karl Egil; Negusie, Ayele H.; Rise, Frode; Teklu, Solomon & Østby, Ole Benny
(2003).
Indolizines as Novel Potent Inhibitors of 15-Lipoxygenase.
Bioorganic & Medicinal Chemistry.
ISSN 0968-0896.
11,
p. 5409–5415.
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Bråthe, Anders; Gundersen, Lise-Lotte; Nissen-Meyer, Jon; Rise, Frode & Spilsberg, Bjørn
(2003).
Cytotoxic activity of 6-alkanyl- and 6-alkenylpurines.
Bioorganic & Medicinal Chemistry Letters.
ISSN 0960-894X.
13,
p. 877–880.
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Gundersen, Lise-Lotte; Negusie, Ayele H.; Rise, Frode & Østby, Ole Benny
(2003).
Antimycobacterial activity of 1-substituted indolizines.
Archiv der Pharmazie.
ISSN 0365-6233.
336,
p. 191–195.
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Bråthe, Anders; Andresen, Geir; Gundersen, Lise-Lotte; Malterud, Karl Egil & Rise, Frode
(2002).
Antioxidant activity of synthetic cytokinin analogues: 6-Alkynyl- and 6-alkenylpurines as novel 15-lipoxygenase inhibitors.
Bioorganic & Medicinal Chemistry.
ISSN 0968-0896.
10,
p. 1581–1586.
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Andresen, Geir; Gundersen, Lise-Lotte; Nissen-Meyer, Jon; Rise, Frode & Spilsberg, Bjørn
(2002).
Cytotoxic and Antibacterial Activity of 2-Oxopurine Derivatives.
Bioorganic & Medicinal Chemistry Letters.
ISSN 0960-894X.
12,
p. 567–569.
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Aabel, Siri; Fossheim, Sigrid Lise & Rise, Frode
(2001).
"Nuclear magnetic resonance (NMR) studies of homeopathic solutions.".
British Homeophatic Journal.
90,
p. 14–20.
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http://folk.uio.no/froderi/Aabel.pdf
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Andresen, Geir; Eriksen, Aud Else Berglen; Dalhus, Bjørn; Gundersen, Lise-Lotte & Rise, Frode
(2001).
Synthesis of 6-substituted purin-2-ones with potential cytokinin activity.
Journal of the Chemical Society. Perkin transactions 1.
ISSN 0300-922X.
p. 1662–1672.
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http://folk.uio.no/froderi/GeirAndresen3.pdf
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Rise, Frode; Andresen, Geir & Gundersen, Lise-Lotte
(2001).
Synthesis of 2-oxopurine adducts with structural resemblance to Efavirenz and DPC 961 as potential NNRT-inhibitors.
Arkivoc. Free Online Journal of Organic Chemistry.
Volume 2001(x),
p. 35–45.
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http://www.arkat-usa.org/ark/journal/Volume2/Part3/Undheim/KU-247A/247.htm
Abstract
6-Cyclopropylethynyl-6-trifluoromethyl dihydro-2-oxopurines have been prepared with completely regioselective addition of trimethyl(trifluoromethyl)silane and cyclopropylethynylmagnesium bromide to 1,9-dialkylated 2-oxopurines as key-steps. The target compounds are structurally related to the Non-Nucleoside reverse transcriptase inhibitors Efavirenz and DPC 961
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Rise, Frode; Singh, Pushap G.; Klaveness, Jo & Aasen, Arne Jørgen
(2001).
Lipophilic X-Ray Contrast Agents. Diatrizoyl Double Esters with Cholesterol and Cholic Acid.
Arkivoc. Free Online Journal of Organic Chemistry.
Volume 2001(x),
p. 7–15.
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http://www.arkat-usa.org/ark/journal/Volume2/Part3/Undheim/KU-205A/205.htm
Abstract
Potential biodegradable and organ-specific X-ray contrast agents have been prepared by linking diatrizoic acid to cholesterol and cholic acid, respectively, via a spacer group containing a carbonate double ester. In vitro experiments revealed that the cholic acid esters were enzymatically degraded in the presence of pig liver esterase, while the double esters with cholesterol appeared to be stable, possibly due to low solubility in water.
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Sing, P. G.; Klaveness, Jo; Rise, Frode & Aasen, Arne Jørgen
(2001).
Lipophilic X-Ray Contrast Agents Diatrizoyl Double Esters with Cholesterol and Cholic Acid.
Archive for Organic Chemistry (Arkivoc).
2(8).
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Potential biodegradable and organ-specific X-ray contrast agents have been prepared by linking diatrizoic acid to cholesterol and cholic acid, respectively, via a spacer group containing a carbonate double ester. In vitro experiments revealed that the cholic acid esters were enzymatically degraded in the presence of pig liver esterase, while the double esters with cholesterol appeared to be stable, possibly due to low solubility in water.
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Spilsberg, Bjørn; Rise, Frode; Petersen, Dirk & Nissen-Meyer, Jon
(2000).
Secretion of thymidine by hybridoma cells.
In Zoref-Shani, Esther & Sperling, Oded (Ed.),
Advances in experimental medicine and biology: Purine and pyrimidine metabolism in man.
Kluwer Academic / Plenum Publishers, New York.
ISSN 9780306465154.
p. 295–301.
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Netland, Kjetil Andreas; Gundersen, Lise-Lotte & Rise, Frode
(2000).
An Improved Synthesis of Dialkylcyclopropenones.
Synthetic Communications.
ISSN 0039-7911.
30,
p. 1767–1777.
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Østby, Ole Benny; Dalhus, Bjørn; Gundersen, Lise-Lotte; Rise, Frode; Bast, Aalt & Haenen, Guido R. M. M.
(2000).
Synthesis of 1-Substituted 7-Cyano-2,3-diphenylindolizines and Evaluation of Antioxidant Properties.
European Journal of Organic Chemistry.
ISSN 1434-193X.
9(22),
p. 3763–3770.
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Bråthe, Anders; Gundersen, Lise-Lotte; Rise, Frode; Eriksen, Aud Else Berglen; Vollsnes, Ane & Wang, Linnea
(1999).
Synthesis of 6-Alkenyl- and 6-Alkynylpurines with Cytokinin Activity.
Tetrahedron.
ISSN 0040-4020.
55,
p. 211–288.
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Liu, Fusheng; Dalhus, Bjørn; Gundersen, Lise-Lotte & Rise, Frode
(1999).
Nucleophilic Addition and Cycloaddition on 2- and 8-Vinylpurines.
Acta Chemica Scandinavica.
ISSN 0904-213X.
53,
p. 269–279.
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http://folk.uio.no/froderi/Liu.pdf
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Nolsøe, Jens M. J.; Gundersen, Lise-Lotte & Rise, Frode
(1999).
Regiochemistry in Pd-Mediated Coupling between 6,8-Dihalopurines and Organometallic Reagents.
Acta Chemica Scandinavica.
ISSN 0904-213X.
53,
p. 366–372.
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http://folk.uio.no/froderi/Jens2.pdf
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Islam, Gulshan Ara; Greibrokk, Tyge; Rise, Frode & Øvrebø, Steinar
(1999).
Epimerization of benzo(a)pyrene-tetrols after acid hydrolysis, implications for determination of benzo(a)pyrene adducts in protein and DNA.
Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis.
ISSN 0027-5107.
423,
p. 47–54.
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http://www.uio.no/~froderi/Gulshan.pdf
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Borgen, Gerd; Dale, Johannes; Gundersen, Lise-Lotte; Rise, Frode; Krivokapic, Alexander & Øverås, Anniken Thomsen
(1998).
Conformations of 11- and 14-membered Ring Monolactams.
Acta Chemica Scandinavica.
ISSN 0904-213X.
52,
p. 1110–1115.
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http://www.uio.no/~froderi/publications.html
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Nolsøe, Jens M. J.; Gundersen, Lise-Lotte & Rise, Frode
(1998).
Synthesis of 8-Halopurines by Reaction of Lithiated Purines with Appropriate Halogen Donors.
Synthetic Communications.
ISSN 0039-7911.
28(23),
p. 4303–4315.
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http://folk.uio.no/froderi/publications.html
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Nasir, Ahmad Izuddin; Gundersen, Lise-Lotte; Rise, Frode; Antonsen, Øyvind; Kristensen, Trond & Langhelle, Bjarte
[Show all 10 contributors for this article]
(1998).
Inhibition of Lipid Peroxidation mediated by Indolizines.
Bioorganic & Medicinal Chemistry Letters.
ISSN 0960-894X.
8(14),
p. 1829–1832.
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Esters, ethers, carbonates and carbamates of 1-indolizinols and azain dolizinols exhibit a profound inhibition of lipid peroxidation in vit ro. The antioxidants were prepared by cyclization of pyridines and di azines with diphenylcyclopropenone followed by introduction of the O- substituent.
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Øverås, Anniken Thomsen; Gundersen, Lise-Lotte & Rise, Frode
(1997).
Lewis Acid Mediated Diels-Alder Reactions of 6-Vinylpurines.
Tetrahedron.
ISSN 0040-4020.
53,
p. 1777–1786.
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http://www.uio.no/~froderi/Anniken1.pdf
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Øverås, Anniken Thomsen; Rise, Frode; Gundersen, Lise-Lotte & Bakkestuen, Anne Kristin Vibstad
(1997).
Addition of Nucleophiles to 6-Vinylpurines.
Acta Chemica Scandinavica.
ISSN 0904-213X.
51,
p. 1116–1124.
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http://www.uio.no/~froderi/Anniken2.pdf
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Andresen, Geir; Gundersen, Lise-Lotte & Rise, Frode
(1996).
Regiochemistry in Addition of Grignard Reagents to N,N-Dibenzylated 2-Purinones.
Tetrahedron.
ISSN 0040-4020.
52,
p. 12979–12992.
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http://folk.uio.no/froderi/publications.html
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Langli, Geir; Gundersen, Lise-Lotte & Rise, Frode
(1996).
Regiochemistry in Stille Couplings of 2,6-Dihalopurines.
Tetrahedron.
ISSN 0040-4020.
52,
p. 5625–5638.
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http://folk.uio.no/froderi/publications.html
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Borgen, Gerd; Dale, Johannes; Rise, Frode & Gundersen, Lise-Lotte
(1996).
Conformations and Conformational Processes of Undecylolactam.
Magnetic Resonance in Chemistry.
ISSN 0749-1581.
34,
p. 289–292.
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http://folk.uio.no/froderi/publications.html
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Andresen, Geir; Gundersen, Lise-Lotte; Lundmark, Max; Sundell, Staffan & Rise, Frode
(1995).
Regioselective Addition of Grignard Reagents to a 2-Oxopurinium Salt.
Tetrahedron.
ISSN 0040-4020.
51,
p. 3655–3664.
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http://folk.uio.no/froderi/GeirAndresen1.pdf
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Gundersen, Lise-Lotte; Rise, Frode & Undheim, Kjell
(1995).
Zirconium Tetraisopropoxide.
In Paquette, Leo A. (Eds.),
Encyclopedia of Reagents for Organic Synthesis.
John Wiley & Sons.
ISSN 9780471936237.
p. 5581–5582.
Full text in Research Archive
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Gundersen, Lise-Lotte; Rise, Frode & Undheim, Kjell
(1995).
Zirconium(IV) Chloride.
In Paquette, Leo A. (Eds.),
Encyclopedia of Reagents for Organic Synthesis.
John Wiley & Sons.
ISSN 9780471936237.
p. 5580–5581.
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Gundersen, Lise-Lotte; Rise, Frode & Undheim, Kjell
(1995).
Titanium(III) Chloride.
In Paquette, Leo A. (Eds.),
Encyclopedia of Reagents for Organic Synthesis.
John Wiley & Sons.
ISSN 9780471936237.
p. 4911–4913.
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Gundersen, Lise-Lotte; Rise, Frode & Undheim, Kjell
(1995).
Titanium(IV) Chloride.
In Paquette, Leo A. (Eds.),
Encyclopedia of Reagents for Organic Synthesis.
John Wiley & Sons.
ISSN 9780471936237.
p. 4913–4920.
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Gundersen, Lise-Lotte; Rise, Frode & Undheim, Kjell
(1995).
Methylzirconium Tributoxide.
In Paquette, Leo A. (Eds.),
Encyclopedia of Reagents for Organic Synthesis.
John Wiley & Sons.
ISSN 9780471936237.
p. 3645–3646.
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Gundersen, Lise-Lotte; Rise, Frode & Undheim, Kjell
(1995).
Zirconium(III) Chloride.
In Paquette, Leo A. (Eds.),
Encyclopedia of Reagents for Organic Synthesis.
John Wiley & Sons.
ISSN 9780471936237.
p. 5580.–5580..
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Borgen, Gerd; Dale, Johannes; Gundersen, Lise-Lotte & Rise, Frode
(1995).
Conformations and Conformational Interconversions of Pelargolactam.
Magnetic Resonance in Chemistry.
ISSN 0749-1581.
33,
p. 252–255.
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Gundersen, Lise-Lotte; Langli, Geir & Rise, Frode
(1995).
Regioselective Pd-Mediated Coupling between 2,6-Dichloropurines and Organometallic reagents.
Tetrahedron Letters.
ISSN 0040-4039.
36,
p. 1945–1948.
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Gundersen, Lise-Lotte; Bakkestuen, Anne Kristin Vibstad; Rise, Frode; Aasen, Arne Jørgen & Øverås, Harald
(1994).
6-Halopurines in Palladium-Catalyzed Coupling with Organotin and Organozinc Reagents.
Tetrahedron.
ISSN 0040-4020.
50,
p. 9743–9756.
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Hare, Brian J.; Aubin, Yves; Rise, Frode & Prestegard, James H.
(1994).
13C-NMR Studies of Wheat Germ Agglutinin Interactions with N-Acetylglucosamine at a Magnetically oriented Bilayer Surface.
Biochemistry.
ISSN 0006-2960.
33,
p. 10137–10148.
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Trost, Barry; Romero, D. L. & Rise, Frode
(1994).
Pd-Catalyzed Cycloisomerization to 1,2-Dialkylidenecycloalkanes. 2. Alternative Catalyst System.
Journal of the American Chemical Society.
ISSN 0002-7863.
116,
p. 4268–4278.
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Sandosham, Jessie; Rise, Frode & Undheim, Kjell
(1993).
Regioselective Substitution in Triflyloxypyrimidines and Chloropyrimidines using Zinc and Tin Reagents.
Heterocycles.
ISSN 0385-5414.
35,
p. 235–244.
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Gogoll, Adolf; Gundersen, Lise-Lotte; Valli, Mats & Rise, Frode
(1993).
Alkylation and Covalent Adduct Formation of 2-Oxopurine.
Heterocycles.
ISSN 0385-5414.
36,
p. 231–235.
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Borgen, Gerd; Rise, Frode & Dale, Johannes
(1993).
Conformations and Conformational Interconversions of Enantholactam.
Magnetic Resonance in Chemistry.
ISSN 0749-1581.
31,
p. 855–858.
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Borgen, Gerd; Rise, Frode & Dale, Johannes
(1993).
Low-Temperature NMR of e-Caprolactam.
Magnetic Resonance in Chemistry.
ISSN 0749-1581.
31,
p. 51–53.
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Gundersen, Lise-Lotte; Rise, Frode & Undheim, Kjell
(1992).
Aryl- and Alkynyltri-isopropoxytitanium Reagents in Regioselective Carbon-Carbon Bond Formation in Azines.
Tetrahedron.
ISSN 0040-4020.
48,
p. 5647–5656.
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Gundersen, Lise-Lotte; Benneche, Tore; Rise, Frode; Gogoll, Adolf & Undheim, Kjell
(1992).
Regiochemistry and Stereochemistry in Pd(0)-Catalyzed Allylic Alkylation of Nucleoside Bases.
Acta Chemica Scandinavica.
ISSN 0904-213X.
46,
p. 761–771.
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Dale, Johannes; Rise, Frode; Rømming, Christian & Sigvartsen, Turid
(1992).
The Preparation and Conformational Studies of 5, 11, 11, 17, 17, 23, 23-Octamethyl-1, 3, 7, 9, 13, 15, 21-octaazaquinquecyclo [19.3.1.13,7.19,13.115,19] octacosane.
Acta Chemica Scandinavica.
ISSN 0904-213X.
46,
p. 1200–1203.
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Bäckvall, Jan-Erling & Rise, Frode
(1989).
2-(Phenylsulfonyl)-1,3-dienes in asymmetric Diels-Alder reactions with Chiral Enamines and Enol Ethers.
Tetrahedron Letters.
ISSN 0040-4039.
30,
p. 5347–5348.
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Rise, Frode & Undheim, Kjell
(1989).
Sodium 2-Mercaptoethanesulfonate in Reversible Adduct Formation and Water Solubilization.
Acta Chemica Scandinavica.
ISSN 0904-213X.
43,
p. 489–492.
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Trost, Barry; Lee, Donna C. & Rise, Frode
(1989).
A New Palladium Catalyst for Intramolecular Carbametallation of Enynes.
Tetrahedron Letters.
ISSN 0040-4039.
30,
p. 651–654.
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Rise, Frode; Nordenson, Svein; Bouzga, Aud. M. & Undheim, Kjell
(1988).
Structure Determination of (Z)-5-Chloro-1-methyl-4H-4-phenacylidene-2(1H)-pyrimidinone.
Acta Crystallographica.
ISSN 0365-110X.
C44,
p. 1298–1300.
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Rise, Frode; Grace, David & Undheim, Kjell
(1988).
Ethynyltriisopropoxytitanium reactions with Pyrimidinones.
Journal of Organometallic Chemistry.
ISSN 0022-328X.
338,
p. 341–346.
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Rise, Frode & Trost, Barry
(1987).
A Reductive Cyclization of 1,6- and 1,7-Enynes.
Journal of the American Chemical Society.
ISSN 0002-7863.
109,
p. 3161–3163.
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Klaveness, Jo; Rise, Frode & Undheim, Kjell
(1986).
Synthesis of 1,2-Dithiolan-2-ylium and 1,3-Dithian-2-ylium Tetrafluoroborate Salts.
Acta Chemica Scandinavica.
ISSN 0904-213X.
B40,
p. 398–399.
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Klaveness, Jo; Rise, Frode & Undheim, Kjell
(1986).
Organotin Derivates in the Umpolung of 1,3-Dithian-2-ylides to 1,3-Dithian-2-ylium Salts.
Journal of Organometallic Chemistry.
ISSN 0022-328X.
303,
p. 189–195.
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Rise, Frode; Høseggen, Tom & Undheim, Kjell
(1986).
Tetra-isopropoxyzirconium and Tri-isopropoxy-aluminum in Regioselective Reduction of Pyrimidinones.
Journal of the Chemical Society. Perkin transactions 1.
ISSN 0300-922X.
p. 849–850.
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Klaveness, Jo; Rise, Frode & Undheim, Kjell
(1986).
Reactions of 1,3-Dithiolan-2-ylium and 1,3-Dithian-2-ylium Tetrafluoroborates and Ambident 2-Styryl Derivates.
Acta Chemica Scandinavica.
ISSN 0904-213X.
B40,
p. 373–380.
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Rise, Frode & Undheim, Kjell
(1985).
Regioselectivity in the Reactions of Aryl-isopropoxy-titanium with Pyrimidinones.
Journal of the Chemical Society. Perkin transactions 1.
ISSN 0300-922X.
p. 1997–1999.
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Ellefsen, Christiane Færestrand; Wold, Christian Winther; Wilkins, Alistair L.; Rise, Frode & Samuelsen, Anne Berit C.
(2021).
Water-soluble mannogalactan and β-glucans from Pleurotus eryngii fruiting bodies, their activity and affinity for TLR2 and dectin-1 receptors.
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Hvinden, Ingvild Comfort; Rise, Frode; Berg, Henriette Engen; Lundanes, Elsa & Wilson, Steven Ray Haakon
(2018).
Approaches to untargeted metabolomics of glioblastoma: NMR and MS.
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Furse, Samuel Robert; Jakubec, Martin; Rise, Frode; Williams, Hew; Rees, Catherine & Halskau, Øyvind
(2017).
Does the lipid fractio of Listeria innocua change as a function of the cell cycle?
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Nguyen, Tien; Kenton, Nathaniel T.; Adu-Amprawun, Daniel; Okumu, Anthony A.; Zhang, Zhingao & Chen, Yong
[Show all 14 contributors for this article]
(2017).
Final twist in marine toxin structural saga.
Chemical & Engineering News, 95(49), December 14, 2017 [Science & Technology, News of The Week].
Chemical & engineering news (Print).
ISSN 0009-2347.
95(49),
p. 9–9.
doi:
10.1021/cen-09549-notw7.
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In the mid-1990s, scientists started to notice cases across Europe of people falling ill from a new kind of shellfish food poisoning. The culprit, researchers discovered, was a family of marine toxins called azaspiracids. The structures of these amorphous toxins have been difficult for chemists to pin down, though some have come very close.
A pair of papers from the laboratory of Craig J. Forsyth at Ohio State University now corrects the stereochemistry of a key position in azaspiracid-3 and details a total synthesis of the reassigned structure (Angew. Chem. Int. Ed. 2017, DOI: 10.1002/anie.201711006; Angew. Chem. Int. Ed. 2017, DOI: 10.1002/anie.201711008). A synthetic route to the azaspiracids along with accurate structures could help scientists develop assays to detect the toxins in food.
Forsyth’s lab had been working on an azaspiracid synthesis in 2004 when K. C. Nicolaou, then at Scripps Research Institute California, reported a 96-step synthesis that revised the azaspiracids’ originally reported structure. Using the 2004 structure as a target, Forsyth’s group devised a new total synthesis. But when the chemists used liquid chromatography to compare their newly synthesized azaspiracid-3 with an authentic sample, they found that the compounds’ retention times didn’t match.
After some head-scratching, Forsyth says, they suspected that the stereochemistry of an alcohol group may have been misassigned in the 2004 structure. Forsyth’s team definitively set the stereochemistry of the C20 alcohol, whereas the Nicolaou synthesis could have yielded either stereoisomer, possibly leading to a misassignment.
The researchers chemically inverted the alcohol’s configuration, and were “overjoyed” when the resulting compound’s retention time matched that of the natural product. While previous total syntheses did succeed in making the correct natural product, they had misassigned one of the molecule’s 19 stereocenters.
Nicolaou, now at Rice University, congratulated the team for their “meticulous” efforts that led to azaspiracid’s final structural revision. “That they were able to decipher the last detail for the correct structure as they did is a testament not only to their brilliant and scholarly work but also to the current powerful state of the art of total synthesis and the modern, high-resolution analytical techniques that support it.”
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Georgiev, Yordan Nikolaev; Paulsen, Berit Smestad; Kiyohara, Hiroaki; Číž, Milan; Ognyanov, Manol H. & Vašíček, Ondřej
[Show all 15 contributors for this article]
(2017).
Erratum to "The common lavender (Lavandula angustifolia Mill.) pectic polysaccharides modulate phagocytic leukocytes and intestinal Peyer's patch cells" (Carbohydr. Polym. (2017) 174 (948-959) (S0144861717307774) (10.1016/j.carbpol.2017.07.011)).
Carbohydrate Polymers.
ISSN 0144-8617.
177,
p. 469–470.
doi:
10.1016/j.carbpol.2017.09.037.
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Kildahl-Andersen, Geir; Nytoft, Hans Peter; Weijers, Johan W. H. & Rise, Frode
(2016).
Structure elucidation of rearranged and degraded oleananes isolated from crude oils.
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Stanic, Ana; Uhlig, Silvio; Rise, Frode; Hofgaard, Ingerd Skow & Miles, Christopher Owen
(2016).
Identification of mercapturic acid conjugates of deoxynivalenol in cereals.
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Uhlig, Silvio; Kryuchkov, Fedor; Gwinn, Jesse; Ivanova, Lada; Fæste, Christiane Kruse & Miles, Christopher Owen
[Show all 11 contributors for this article]
(2014).
CiguaPIRE: Norwegian contributions to advancing the global understanding of ciguatera.
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The international CiguaPIRE project focuses on three major research objectives: 1) To evaluate epiphyte and Gambierdiscus community diversity and macrophyte host selectivity in Caribbean coral reef ecosystems; 2) To characterize the meta-metabolome of these communities, structurally elucidate key metabolites, and develop methods to evaluate their toxicity and functional role; and 3) To identify chemical biomarkers in reef bio-indicator species and model their fate in reef food webs. The Norwegian CiguaPIRE project team, in close collaboration with the US and Canadian teams, primarily contribute towards objective 2. We have studied the mass spectrometric characteristics of Caribbean ciguatoxins (CTX), i.e. the epimers C-CTX-1 and -2, using a sensitive UHPLC–HRMS/MS approach in order to identify product ions of diagnostic value. Based on these data, we were able to determine the chemical structures of two analogues, C-CTX-3 and -4. By applying reduction and oxidation reactions, we showed that C-CTX-1 and -2 can be chemically converted into C-CTX-3 and -4. Our recent efforts concerned the optimization of a simple derivatization method for CTX-1 and -2, leading to signal enhancement in mass spectrometry-based detection of the toxins.
Additional collaborative efforts have been focused on cross-species comparison of hepatic biotransformation by in vitro metabolism assays. Using a variety of wild caught fish species from the northern Gulf of Mexico, livers were harvested and used in the preparation of microsomes. Oxidative and conjugative metabolism reactions were studied using semi-pure CTX-1 and -2. The experiments identified a detoxification pathway that had not previously been described for this class of toxins in fish, and which was absent when we performed corresponding experiments using rat or human liver microsomes. These data will aid in our trans-ocean efforts to better understand CTX toxicity and pathways of detoxification in fish.
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Langseth, Eirin; Tråseth, Eline Aa.; Scheuermann, Margaret L.; Rise, Frode; Heyn, Richard H & Tilset, Mats
(2014).
Gold(III) complexes: Synthesis and characterization.
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Miles, Christopher O.; Wilkins, Alistair Lawrence; Holland, Patrick T.; McNabb, Paul; Rhodes, Lesley R. & Edwards, Pat
[Show all 8 contributors for this article]
(2012).
Rangiputamide from Prorocentrum lima: structure elucidation by NMR.
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Prorocentrum is a genus of benthic dinoflagellate microalgae with a world-wide distribution. P. lima is a species commonly found in northern harbours of New Zealand and produces okadaic acid analogues. During LC-MS (ESI+) screening of P. lima culture extracts, several strains including one isolated from Rangiputa, Rangaunu Harbour, were noted to produce an unusual N-containing compound MH+ 856 that eluted amongst the diol esters of okadaic acid. These strains were bulk-cultured and extracts of the cell pellets were fractionated by column chromatography, and the N-compound was isolated by preparative C18-HPLC in high purity (4.2 mg, MF C50H81NO10 from HRMS of MH+, 11 rings/double bonds). Acetylation followed by LC-MS indicated the presence of 4 reactive OH groups. The structure of rangiputamide (1) (1 mg) was deduced from an extensive array of 2D NMR experiments in CD3OD and d6-DMSO using double-solvent suppression. 1D and 2D NOESY and ROESY data is being analyzed to obtain stereochemical information. DMSO as solvent was useful in revealing the amide and hydroxyl protons and assigning some of the ether linkages and the epoxide.
Prorocentrum spp. can produce several macrolides as well as okadaic acid, but this polyether structure is unprecedented. The matched pair of linked spiroketal 6-membered rings are similar to those in okadaic acid but with different substituent and linking groups. Rangiputamide was not detected in cultures of a strain of P.lima from Spain. It was non-toxic in mouse bioassay (i.p. injection) and not appreciably cytotoxic to Vero or P388 mammalian cells. The physiological or potential ecological function for 1 remains unknown.
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Austarheim, Ingvild Marie; Michaelsen, Terje Einar; Inngjerdingen, Marit; Rise, Frode; Diallo, Drissa & Paulsen, Berit Smestad
(2009).
Novel Pectin-like polysaccharides with immunomodulating properties from the bark of the malian medicinal tree Cola cordifolia.
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Wilson, Steven Ray Haakon; Petersen, Dirk; Rise, Frode & Krauss, Stefan
(2009).
Exporing the chemistry of the anti-cancer drug cycopamine with LC-MS and NMR.
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Gundersen, Lise-Lotte; Rise, Frode; Undheim, Kjell & Huerou, Y. Le
(2009).
Zirconium(IV) Chloride.
In Paquette, Leo A. (Eds.),
Encyclopedia of Reagents for Organic Synthesis. 2. Ed.
John Wiley & Sons.
ISSN 9780470017548.
p. 10965–10970.
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Wilson, Steven Ray Haakon; Strand, Martin Frank; Rise, Frode; Petersen, Dirk; Lundanes, Elsa & Krauss, Stefan
(2009).
NMR and LC-MS Analysis of Natural and Acid-Induced Isomers of Cyclopamine.
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Holm, Anders; Rise, Frode; Sessler, Nicole; Sollid, Ludvig Magne; Undheim, Kjell & Fleckenstein, Burkhard
(2007).
Specific Modification and Subsequent Mass Spectrometric Detection of Citrulline Containing Peptides.
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The posttranslational deimination of polypeptide-bound arginine residues is known as citrullination and is catalyzed by a family of Ca2+ dependent enzymes called peptidylarginine deiminases. Immune reactions to such citrulline containing proteins appear to be central in the immunopathogenesis of rheumatoid arthritis. Consequently there is a need to characterize which proteins in the inflamed joints of rheumatoid patients contain citrulline residues in situ. As demonstrated for a series of other posttranslational modifications, such as phosphorylation and glycosylation, the characterization of citrullinated proteins and peptides in complex mixtures is greatly facilitated by techniques allowing their specific enrichment and/or detection. So far such methods are not available for citrullinated peptides.
As a first step towards the directed analysis of citrullinated proteins and peptides in rheumatoid arthritis, this study presents a method for the specific modification of peptide bound citrulline residues. This chemical reaction uses 2,3-butanedione and antipyrine as modifying reagents and is performed in 25-50 % TFA at 37°C. The modification shifts the mass of citrullinated peptides by 238 Da. NMR was applied to elucidate the structure of the modification product using N-butylurea as a model compound. Modified citrulline residues absorb at 464 nm enabling their selective detection and fractionation in liquid chromatography (LC).
In order to verify the chemical structure of the modification and to investigate the generation of modification-specific fragment ions, modified citrulline containing peptides were subjected to collision induced dissociation experiments. Two fragments ions characteristic for modified citrulline residues were detected and will be presented. The usefulness of these signature ions to specifically detect modified citrullinated peptides in heterogeneous mixtures by nano LC-MS/MS will be discussed. Analysis was performed on ESI-ion trap, ESI-q-TOF and MALDI-TOF/TOF mass spectrometers.
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Rise, Frode; Krengel, Ute; Gørbitz, Carl Henrik; Nissen-Meyer, Jon; Kristiansen, Per Eugen & Davies, William
(2007).
THE UNIVERSITY OF OSLO BIOMOLECULAR STRUCTURE PLATFORM.
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In-depth understanding of the mode of action of proteins and other biomolecules relies to a large extent on knowledge of their three-dimensional structures. Such knowledge is necessary for understanding bio-recognition and response processes, and is required for rational design of specific pharmacological reagents. Consequently it is essential for research in the molecular biosciences to determine the structures of biomolecules. We have applied for funding. with a grant proposal to EMBIO, to establish and manage a “Biomolecular Structure Platform” at the University of Oslo. The intention of the platform is to make methods for structure determination of biomolecules available to a larger group of the biomedical and biological communities. Moreover, it is also aimed to provide assistance in large-scale production and purification of proteins for structural studies. The principle objectives and purposes of the “Biomolecular Structure-Platform” are to:
1. Establish and develop methods for large-scale production and purification of isotope labeled proteins and peptides for structural analysis.
2. Determine the structure of proteins under investigation by the contributing groups, and thereby gain detailed insight into how these proteins function at a molecular level.
3. Serve other research groups that need assistance in production and purification of 13C, 15N and Se-Met labeled proteins and peptides.
4. Provide assistance to other research groups that wish to analyze the structure of proteins, peptides and other biomolecules by NMR-spectroscopy and X-ray crystallography, mainly in the context of collaborative research.
5. Strengthen the expertise in both three-dimensional structure- and function- analysis of biological macromolecules by performing a variety of experiments and employing different structure determination tools and also by educating Ph.D.- and Master- degree students in structure determination and analysis.
6. Strengthen the expertise in large-scale production and purification of proteins by educating Ph.D.- and Master- degree students in relevant techniques.
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Rise, Frode
(2007).
NMR i Life Science. Muligheter og eksempler.
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I foredraget vil eksempler på bruk av kjernemagnetisk resonans-spektropi (NMR) i biomedisinske problemstillinger bli presentert. Begrensinger med hensyn til substansmengder og renhet omtales.
NMR-laboratoriets ved UiO, laboratoriets instrumentering og organisering vil presenteres. De forskjellige instrumentene er dedikert til forskjellige vitenskaplige formål. Samlokaliseringen gir stordriftsfordeler og mulighet for å utnytte ledig kapasitet på tvers av brukergruppene. Det nyeste instrumentet ipå laboratoriet danner en hjørnesten i "The University of Oslo Biomolecular Structure Platform".
Hvis internettforbindelsen til Holmen Fjordhotell er god vil et reelt NMR-opptak vises.
På grunn av begrenset personelltilgang må interesserte brukere enten innlede samarbeid eller selv lære seg metodene. Organisert grunnopplæring gis i modul 1 i kurset KJM-MEF4010: http://www.uio.no/studier/emner/matnat/ kjemi/KJM-MEF4010/v07/ og i det videregående emnet KJM5250 http://www. uio.no/studier/emner/matnat/kjemi/KJM5250/v07/. Ytterligere opplæring og innøving av metoder må foretas før man er kompetenet til å gjennomføre DNA/RNA- og proteinforsøk.
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Malerød, Helle; Wilson, Steven Ray Haakon; Petersen, Dirk; Rise, Frode; Lundanes, Elsa & Greibrokk, Tyge
(2007).
Structure determination using on-line LC-MS/NMR.
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Larsen, Kristofer; Rise, Frode; Petersen, Dirk; Miles, Christopher O. & Wilkins, Alistair L.
(2006).
Clarification of the C-35 Stereochemistry of DTX-1.
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Mmatli, Edward M; Rise, Frode; Abegaz, Berhanu m & Bezabih, Merhatibeb
(2006).
Phytochemical Studies on the aerial parts of Blepharis Aspera (Acatthaceae).
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Mmatli, Edward M; Rise, Frode; Abegaz, Berhanu m & Bezabih, Merhatibeb
(2006).
Phytochemical Studies on the aerial parts of Blepharis Aspera (Acatthaceae).
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Larsen, Kristofer; Rise, Frode; Petersen, Dirk; Miles, Christopher O. & Wilkins, Alistair L.
(2006).
Clarification of the C-35 Stereochemistry of DTX-1.
Full text in Research Archive
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Holm, Anders; Rise, Frode; Sessler, Nicole; Sollid, Ludvig Magne; Undheim, Kjell & Fleckenstein, Burkhard
(2006).
Specific Modification and Subsequent Mass Spectrometric Detection of Citrulline Containing Peptide.
Full text in Research Archive
Show summary
The posttranslational deimination of polypeptide-bound arginine residues is known as citrullination and is catalyzed by a family of Ca2+ dependent enzymes called peptidylarginine deiminases. Immune reactions to such citrulline containing proteins appear to be central in the immunopathogenesis of rheumatoid arthritis. Consequently there is a need to characterize which proteins in the inflamed joints of rheumatoid patients contain citrulline residues in situ. As demonstrated for a series of other posttranslational modifications, such as phosphorylation and glycosylation, the characterization of citrullinated proteins and peptides in complex mixtures is greatly facilitated by techniques allowing their specific enrichment and/or detection. So far such methods are not available for citrullinated peptides.
As a first step towards the directed analysis of citrullinated proteins and peptides in rheumatoid arthritis, this study presents a method for the specific modification of peptide bound citrulline residues. This chemical reaction uses 2,3-butanedione and antipyrine as modifying reagents and is performed in 25-50 % TFA at 37°C. The modification shifts the mass of citrullinated peptides by 238 Da. NMR was applied to elucidate the structure of the modification product using N-butylurea as a model compound. Modified citrulline residues absorb at 464 nm enabling their selective detection and fractionation in liquid chromatography (LC).
In order to verify the chemical structure of the modification and to investigate the generation of modification-specific fragment ions, modified citrulline containing peptides were subjected to collision induced dissociation experiments. Two fragments ions characteristic for modified citrulline residues were detected and will be presented. The usefulness of these signature ions to specifically detect modified citrullinated peptides in heterogeneous mixtures by nano LC-MS/MS will be discussed. Analysis was performed on ESI-ion trap, ESI-q-TOF and MALDI-TOF/TOF mass spectrometers.
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Malerød, Helle; Wilson, Steven Ray Haakon; Rise, Frode; Lundanes, Elsa & Greibrokk, Tyge
(2006).
Pre-concentration of compounds on a micro-solid phase extraction (SPE) column for LC-NMR analysis.
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Rise, Frode; Mmatli, Edward Eddie; Malerød, Helle; Wilson, Steven Ray Haakon; Lundanes, Elsa & Greibrokk, Tyge
[Show all 8 contributors for this article]
(2006).
Identification of Phenylethyl Glycosides from Blepharis aspera by LC-UV-SPE-NMR/MS Hyphenation.
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Conclusions
Verbascoside and isoverbascoside were isolated and purified from Blepharis
aspera. An in lab designed LC-UV-SPE-NMR/MS system was successfully used to separate the two compounds and to obtain their 1H NMR data online using a 30 micro liter LC-NMR probe.
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Mmatli, Edward M; Rise, Frode; Abegaz, Berhanu m & Bezabih, Merhatibeb
(2005).
Phytochemical studies on the aerial parts of Blepharis aspera (Acanthanceae).
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Teklu, Solomon; Gundersen, Lise-Lotte; Rise, Frode & Malterud, Karl Egil
(2004).
Indolizines as Novel Potent Inhibitors of 15-Lipoxygenase.
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Bråthe, Anders; Gundersen, Lise-Lotte; Rise, Frode; Malterud, Karl Egil; Nissen-Meyer, Jon & Spilsberg, Bjørn
(2004).
Antioxidant and Cytotoxic Properties of Some 6-Substituted Purines.
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Negussie, Ayele Hailu; Gundersen, Lise-Lotte; Rise, Frode & Østby, Ole Benny
(2004).
Antimycobacterial Activity of Substituted Indolizines.
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Aarnes, Halvor; Eriksen, Aud Else Berglen; Petersen, Dirk & Rise, Frode
(2004).
In Vivo 14N-NMR and 31P-NMR: intracellular pH in Norway spruce (Picea abies) seedlings grown on ammonium or nitrate.
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Bråthe, Anders; Gundersen, Lise-Lotte; Rise, Frode; Nissen-Meyer, Jon & Spilsberg, Bjørn
(2003).
Cytotoxic Activity and Synthesis of 6-Alkenyl and 6-Alkenylpurines.
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Utenova, Bibigul; Malterud, Karl Egil & Rise, Frode
(2003).
Antioxidant Activity of O-Protected (-)-Epigallocatechin-3-gallates.
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Negusie, Ayele H.; Gundersen, Lise-Lotte & Rise, Frode
(2003).
Synthesis of Indolizines with Potential Inhibitory Activity against Mycobacterium Tuberculosis.
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Teklu, Solomon; Gundersen, Lise-Lotte; Malterud, Karl Egil; Rise, Frode & Østby, Ole Benny
(2003).
Indolizines as Novel Potent Inhibitors of 15-Lipoxygenase.
Full text in Research Archive
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Teklu, Solomon; Gundersen, Lise-Lotte; Rise, Frode; Østby, Ole Benny & Malterud, Karl Egil
(2002).
Radical scavenging Properties of Indolizine Derivatives.
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Negusie, Ayele H.; Gundersen, Lise-Lotte; Rise, Frode & Østby, Ole Benny
(2002).
Synthesis of Indolizines with Potential Inhibitory Activity against Mycobacterium Tuberculosis.
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Bråthe, Anders; Gundersen, Lise-Lotte; Rise, Frode & Malterud, Karl Egil
(2001).
Antioxidant Properties of some Cytokinin Analogues.
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Andresen, Geir; Gundersen, Lise-Lotte & Rise, Frode
(2001).
Synthesis of 2-Oxopurine Derivatives as Potential HIV Reverse Transcriptase Inhibitors.
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Andresen, Geir; Gundersen, Lise-Lotte; Nissen-Meyer, Jon; Spilsberg, Bjørn & Rise, Frode
(2001).
Cytotoxic Activity of 2-Oxopurine Derivatives.
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Bakkestuen, Anne Kristin Vibstad; Gundersen, Lise-Lotte & Rise, Frode
(2001).
Synthetic Studies towards Trixagol and Agelasine E.
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Andresen, Geir; Gundersen, Lise-Lotte & Rise, Frode
(2001).
Synthesis of 2-Oxopurine Derivatives as Potential HIV Reverse Transcriptase Inhibitors.
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Bakkestuen, Anne Kristin Vibstad; Gundersen, Lise-Lotte & Rise, Frode
(2001).
Synthetic Studies towards Trixagol and Agelasine E.
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Negusie, Ayele H.; Gundersen, Lise-Lotte; Rise, Frode & Østby, Ole Benny
(2001).
Synthesis of Indolizines with Potential Inhibitory Activity against Mycobacterium Tuberculosis.
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Spilsberg, Bjørn; Rise, Frode; Petersen, Dirk & Nissen-Meyer, Jon
(2001).
SECRETION OF THYMIDINE BY HYBRIDOMA CELLS.
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Myeloma and hybridoma cells have been reported to secrete a low molecular weight growth inhibitory factor (Rønning et al., 1991, Cytotechnology 7, 15-24; Røe, Ø. et al., 1999, Biochem. Biophys. Res. Commun. 254, 138-142). The factor was identified as thymidine by NMR spectroscopy after isolation to homogeneity from hybridoma cell cultures by ultrafiltration, dialysis concentration and reverse phase chromatography under acidic and neutral conditions. Taken together, the results suggest that hybridoma cells and possibly myeloma cells secrete thymidine.
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Bråthe, Anders; Gundersen, Lise-Lotte; Rise, Frode & Malterud, Karl Egil
(2001).
Antioxidant properties of some cytokinin analogues.
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Bråthe, Anders; Gundersen, Lise-Lotte; Rise, Frode & Malterud, Karl Egil
(2001).
Antioxidant properties of some cytokinin analogues.
Full text in Research Archive
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Teklu, Solomon; Gundersen, Lise-Lotte; Rise, Frode; Østby, Ole Benny & Malterud, Karl Egil
(2001).
Radical scavenging properties of indolizine derivatives.
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Spilsberg, Bjørn; Rise, Frode; Petersen, Dirk; Rønning, Øystein W. & Nissen-Meyer, Jon
(2000).
The low-molecular-weight "growth inhibitory factor" produced by hybridoma cell culture identifed as thymidine by NMR-spectroscopy.
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Spilsberg, Bjørn; Rise, Frode; Petersen, Dirk; Rønning, Øystein W. & Nissen-Meyer, Jon
(2000).
The low-molecular-weight "growth inhibitory factor" produced by hybridoma cell cultures identified as thymidine by NMR-spectroscopy.
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Myeloma and hybridoma cells have been reported to secrete a low-molecular-weight growth inhibitory factor (1, 2). This factor was isolated to homogeneity from the media (4.0 liters) of hybridoma cell cultures by ultrafiltration, ¿dialysis concentration¿ and reverse phase chromatography under acidic and neutral conditions. The inhibitory factor was identified as thymidine by NMR spectroscopy.
(1) Rønning, Ø.W., Schartum, M., Winsnes, A. and Lindberg, G. (1991) Growth limitation in hybridoma cell cultures: The role of inhibitory or toxic metabolites. Cytotechnology 7, 15-24.
(2) Røe, Ø., Brondz, I., Rønning, Ø. and Nissen-Meyer, J. (1999) Isolation of a low-molecular-weight growth inhibitory factor from hybridoma cell cultures. Biochem. Biophys. Res. Commun. 254, 138-142.
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Netland, Kjetil Andreas; Gundersen, Lise-Lotte & Rise, Frode
(2000).
An improved Synthesis of Dialkylcyclopropenones.
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Østby, Ole Benny; Rise, Frode & Gundersen, Lise-Lotte
(2000).
Assignment of 13C Resonances of Indolizines Using Optimised COLOC, HMBC and INADEQUATE NMR.
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Østby, Ole Benny; Gundersen, Lise-Lotte & Rise, Frode
(2000).
Synthesis of 1-Substituted 7-Cyano-2,3-diphenylindolizines as Potential Antioxidants.
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Andresen, Geir; Gundersen, Lise-Lotte & Rise, Frode
(2000).
Synthesis of 6-Substituted 2-Oxopurines as Potential Plant Hormones.
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Rise, Frode
(1999).
A Different Kind of Lecture.
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http://www.bruker.se/unmr99ma.htm
A different kind of lecture! Experiences since 1995 with NMR spectrometers integrated on the University of Oslo Network and the Internet
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Nolsøe, Jens M. J.; Rise, Frode & Gundersen, Lise-Lotte
(1998).
Synthesis of 6,8-Dihalopurines and Studies of their Reactivity in Cross Coupling Reactions.
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Øverås, Anniken Thomsen; Gundersen, Lise-Lotte & Rise, Frode
(1998).
Nucleophilic Addition and Diels-Alder Reactions on 6-Vinylpurines.
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Bråthe, Anders; Gundersen, Lise-Lotte; Rise, Frode; Eriksen, Aud Else Berglen & Wang, Linnea
(1998).
Synthesis of Cytokinin Analogues.
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Bråthe, Anders; Rise, Frode & Gundersen, Lise-Lotte
(1997).
Heck koblinger på vinylpurin; syntese av potensielle cytokininer.
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Nolsøe, Jens M. J.; Rise, Frode & Gundersen, Lise-Lotte
(1997).
Regiokjemiske studier av kobling mellom 6,8-dihalopuriner og organometalliske reagenser.
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Nasir, Achmad I.; Gundersen, Lise-Lotte; Rise, Frode; Bast, Aalt & Haenen, Guido R. M. M.
(1997).
Syntese av indolisiner med antioksidant egenskaper.
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Langli, Geir; Gundersen, Lise-Lotte & Rise, Frode
(1996).
2,6-Dihalopuriner i regioselektive palladiumkatalyserte koblinger med organotinnreagenser.
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Thomsen, Anniken; Gundersen, Lise-Lotte & Rise, Frode
(1996).
Nukleofile addisjoner og sykloaddisjoner til 6-vinylpuriner.
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Gundersen, Lise-Lotte; Langli, Geir; Rise, Frode & Thomsen, Anniken
(1996).
Pd-Catalyzed C-C Bond Formation in Purines.
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Andresen, Geir; Gundersen, Lise-Lotte & Rise, Frode
(1996).
Regioselective Addition of Grignard Reagents to 2-Purinone Derivatives.
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Andresen, Geir; Gundersen, Lise-Lotte & Rise, Frode
(1996).
Regioselektiv C-C bindingsdannelse på benzylerte 2-oksopuriner.
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Gundersen, Lise-Lotte; Langli, Geir; Rise, Frode & Øverås, Harald
(1995).
Strategier for karbon - karbon bindingsdannelse i puriner.
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Ugland, Sigurd; Gundersen, Lise-Lotte; Rise, Frode; Bast, Aalt & Haenen, Guido R. M. M.
(1995).
Syntese av potensielle antioksidanter og nevrobeskyttende forbindelser.
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Langli, Geir; Gundersen, Lise-Lotte & Rise, Frode
(1995).
2,6-Diklorpuriner i Palladium-katalyserte koblinger med organotinn og organosink reagenser.
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Andersen, Geir; Gundersen, Lise-Lotte; Lundmark, Max; Sundell, Staffan & Rise, Frode
(1995).
Dannelse og Alkylering av 2-Oxopurin. Addisjon av Grignard reagenser til et alkylert 2-oxopurinium sal.
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Øverås, Harald; Gundersen, Lise-Lotte; Rise, Frode & Aasen, Arne Jørgen
(1995).
6-Halopuriner i palladium-katalyserte koblinger med organosink reagenser.
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Andresen, Geir; Gundersen, Lise-Lotte & Rise, Frode
(1995).
Structure Determination of 2-Oxopurine Derivatives with NMR.
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Gundersen, Lise-Lotte; Bakkestuen, Anne Kristin; Aasen, Arne Jørgen; Øverås, Harald & Rise, Frode
(1994).
Pd-Catalyzed Carbon - Carbon Bond Formation in Purines.
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Mallia, Vittoria; Uhlig, Silvio; Miles, Christopher Owen; Eriksen, Gunnar Sundstøl; Sandvik, Morten & Rise, Frode
(2020).
Potential endocrine disrupting activity of cyanobacteria: Possible roles for microcystins.
Universitetet i Oslo.
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This thesis investigated the connection between two major global concerns: the infamous cyanobacteria (“blue-green algae”), and the endocrine disruptors, compounds able to interfere with the hormonal system. Do cyanobacteria exert endocrine disrupting activity? Are the cyanobacterial toxins “microcystins” involved? Cyanobacterial extracts, complex combinations of known and unknown compounds including microcystins, were screened using specific in vitro assays to assess their potential endocrine activity. Pure microcystins were also tested. Results showed that cyanobacterial compounds (microcystins, but also other metabolites) could have an endocrine disrupting activity, especially interfering with hormone production and metabolism. Furthermore, a combination of chemical analysis and reactions were used to deepen structural knowledge of microcystins (they are a family including hundreds of congeners!). Seven new microcystin congeners were identified in this work. Resulting data on the endocrine activity of cyanobacteria as well as the discovery of new microcystins highlighted the complexity and the many “unknowns” that remain behind these two global concerns and their interconnection.
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Racz, Beatrix; Wilson, Steven Ray Haakon; Rise, Frode & Lundanes, Elsa
(2018).
Identification of a major UV absorbing compound in goose aqueous humour.
Universitetet i Oslo.
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About 5% of solar radiation comes from the ultraviolet (UV) region. It carries high energy and can do serious damage to living organisms. The eye of animals and humans is a critically exposed area and contains UV absorbing compounds like proteins, tryptophan, tyrosine, ascorbic acid and uric acid in the aqueous humour (AH) for protection. In addition, an unknown component (compound X) which causes red-shift in the UV absorbance spectrum at 254 nm has been observed in heavily exposed species like goose, which migrates at 10 000 m altitude. X is a major absorber. UV measurements confirmed the presence of a compound in geese which has higher absorption at 254 nm compared to other species. Compound X also has fluorescence activity that resembled indole-functionality. Aqueous humour samples from different species (goose, chicken, turkey) were measured by nuclear magnetic resonance spectroscopy (NMR). The proton NMR spectra did not show any specific high abundant compound in the goose eye at the aromatic region compared to the other species, thus NMR could not reveal what made the difference between in UV absorbance. Mass spectrometry with atmospheric pressure photoionization (APPI) has earlier showed that the molar mass of the compound X could be 149 g/mole, which suggests that compound X might be the indole: 5,6-dihydroxyindole (DHI). DHI has a central role in the biosynthesis of melanin which takes place in melanocyte cells. DHI tends to easily be polymerized and one of the results is a notable change in its solubility. It was not possible to obtain a suitable external standard which did not undergo auto-polymerization, mirroring the observations with the isolated compound.To further test the hypothesis of DHI being compound X, reversed phase (RP) high performance liquid chromatography (HPLC) and hydrophilic interaction liquid chromatography (HILIC) were performed. Ascorbic acid co-eluted with the most abundant peak (compound X) in RP-HPLC. In HILIC the most abundant peak was not ascorbic acid. Hence, compound X is not ascorbic acid, and subsequent experiments showed that it was neither the UV absorbing compounds tryptophan, tyrosine or uric acid. After using several analytical tools, the hypothesis that compound X is 5,6-dihydroxyindole was strengthened. However an external standard is still necessary to provide accurate information.
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Hvinden, Ingvild Comfort; Wilson, Steven Ray Haakon; Rise, Frode; Berg, Henriette Engen & Lundanes, Elsa
(2018).
Nuclear magnetic resonance spectroscopy based metabolomics discovers biomarkers of glioblastoma drug response.
Universitetet i Oslo.
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Glioblastoma is the most common and aggressive form of brain cancer. Even with comprehensive treatment regimes, patients face an expected survival of only 15 months. Currently, methods for assessing treatment response are lacking; it is difficult to accurately determine the efficacy of a treatment. The goal of the present study was to contribute to treatment assessment by scouting for metabolic biomarkers occurring in response to exposure to chemotherapeutic agents temozolomide (TMZ) and sepantronium bromide (YM155). Untargeted metabolomics of lysate from cultured glioblastoma cells was carried out with liquid state proton nuclear magnetic resonance (NMR) spectroscopy at resonance frequency 800 MHz. Spectral data were analyzed with two different multivariate statistical methods: principal component analysis (PCA) and partial least squares (PLS) regression. For YM155, two biomarker candidates were found: citric and lactic acid. Citric acid appeared to increase most in samples from cell lines less sensitive to YM155. Lactic acid decreased in all cell lines and was considered a more general biomarker of treatment exposure. TMZ-treated samples were not distinguishable from control samples, most likely due to too short exposure time (24 hours). Analyses with nano hydrophilic interaction liquid chromatography coupled with mass spectrometry (MS) corroborated the findings by NMR spectroscopy and statistical analyses. Both citric acid and lactic acid are biomarker candidates, but a more detailed understanding of their fluctuations in glioblastoma during treatment is needed. Nevertheless, they represent genuine candidates and should be considered for further in vivo magnetic resonance spectroscopy (MRS) studies. In the future, the biomarkers could be monitored with MRS, allowing a more unambiguous and personalized assessment of response to treatment in individual patients.
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Rise, Frode
(2007).
Processing of XWINNMR-data from DPX200, DPX300 and DRX500, and TOPSPIN-data from AV600 and AVII600 with TOPSPIN 1.3 on a Windows 2003 Server.
Frode Rise.
Full text in Research Archive
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Rise, Frode
(2007).
KJM5250 - Organic NMRSpectroscopy Laboratory Experiments - part 1. Pulse width determination, T1 relaxation time constant measurement, 1H-1H Decoupling, nOe Difference Spectroscopy, DEPT.
Frode Rise.
Full text in Research Archive
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Rise, Frode & Petersen, Dirk
(2007).
Processing and plotting of 2D NMR spectra - TOCSY, NOESY and HSQC.
Dirk Petersen and Frode Rise.
Full text in Research Archive
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Rise, Frode
(2007).
KJM5250 - Organic NMR Spectroscopy. Laboratory Experiments - part 2. Homonuclear 2D NMR Spectroscopy. COSY, TOCSY, NOESY, ROESY.
Frode Rise.
Full text in Research Archive
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Rise, Frode
(2007).
KJM4250 - Organic NMR Spectroscopy. Laboratory Experiments - part 3. Heteronuclear 13C detected 2D NMR Spectroscopy. XHCORR (HETCOR) and COLOC Heteronuclear 1H detected 2D NMR Spectroscopy. HMQC, HSQC, HMBC H2BC (HSQC-COSY).
Frode Rise.
Full text in Research Archive
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Wilson, Steven Ray Haakon; Lundanes, Elsa; Rise, Frode & Greibrokk, Tyge
(2007).
On-line multidimensional LC-techniques. Determinations of known and unknown compounds in limited and complex samples.
Universitetet i Oslo.
Full text in Research Archive
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Bakkestuen, Anne Kristin Vibstad; Gundersen, Lise-Lotte & Rise, Frode
(2005).
Synthesis of agelasine E and agelasine analogs as well as 6-aryl and 6-alkenyl purines, and determination of their antimycobacterial activities.
Universitetet i Oslo.
Full text in Research Archive
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Negussie, Ayele Hailu; Gundersen, Lise-Lotte & Rise, Frode
(2004).
Synthesis of Indolizine derivatives and Screeining of Their Antimycobacterial and 15-Lipoxygenase Activity.
Universitetet i Oslo.
Full text in Research Archive
Show summary
Around one-third of the world s population has been infected with Mycobacterium tuberculosis and 5-10% of those with latent infection are expected to develop clinical tuberculosis (TB). It is the major cause of death in developing countries and there has been an
unfortunate resurgence of TB in the industrialized countries. There are about eight million new cases of TB each year, and it has been estimated that about thirty million people will die from tuberculosis in about ten years. Screening of a number of heterocyclic compounds for antimycobacterial activity has resulted in identification of certain indolizine derivatives inhibitors of M. tuberculosis. In this study a
number of indolizines were synthesized, their structure elucidated using 1D and 2D NMR techniques, mass spectrometry and elemental analysis. Antimycobacterial activity was determined by the Tuberculosis Antimicrobial Acquisition and Coordinating Facility
(TAACF).
Most of the synthesized indolizines are found to be active against M. tuberculosis particularly 1-(1-hdroxy-pentyl)-2,3-diphenyl-indolizine-7-carbonitrile 16i, is the most potent indolizine, which showed 100% inhibition at a concentration of 3.3 µg/mL. Some novel indolizines were also tested as inhibitors of 15-lipoxygenase and all of them have, except 35a and 36a, showed better inhibitory activity than quercetin, the well known 15-LO inhibitor. In this study, a one pot synthesis of target compound 26b from 13, with very high yield, developed which otherwise needs multi step synthesis with very low over all yield.
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Rise, Frode; Efskind, Jon; Falch-Pedersen, Mette Lene; Klaveness, Jo & Gunnes, Sølvi
(2001).
Kjell Undheim Symposium in Organic Chemistry 1-2 November 2001 University of Oslo, ISBN 82-996093-0-5.
Universitetet i Oslo.
ISSN 9788299609302.
Full text in Research Archive
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Øverås, Harald; Gundersen, Lise-Lotte; Rise, Frode & Aasen, Arne Jørgen
(1995).
Palladiumkatalyserte koblingsreaksjoner mellom organosinkreagenser og 6-halopuriner og forsøk på syntese av 9-benzyl-6-trialkyltinnpuriner.
Universitetet i Oslo.
Full text in Research Archive
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Nov. 11, 2010 9:00 AM
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Oct. 11, 2026 1:07 PM
