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• Corrales, Jeanne Gaspar; Alonso, Lucia Ramos; González-Sabín, Javier; Ríos-Lombardía, Nicolás; Trevijano-Contador, Nuria & Berg, Henriette Engen [Show all 12 contributors for this article] (2024). Characterization of a selective, iron-chelating antifungal compound that disrupts fungal metabolism and synergizes with fluconazole. Microbiology spectrum. 12(2). doi: 10.1128/spectrum.02594-23. Full text in Research Archive Show summary

  Fungal infections are a growing global health concern due to the limited number of available antifungal therapies as well as the emergence of fungi that are resistant to first-line antimicrobials, particularly azoles and echinocandins. Development of novel, selective antifungal therapies is challenging due to similarities between fungal and mammalian cells. An attractive source of potential antifungal treatments is provided by ecological niches co-inhabited by bacteria, fungi, and multicellular organisms, where complex relationships between multiple organisms have resulted in evolution of a wide variety of selective antimicrobials. Here, we characterized several analogs of one such natural compound, collismycin A. We show that NR-6226C has antifungal activity against several pathogenic Candida species, including C. albicans and C. glabrata, whereas it only has little toxicity against mammalian cells. Mechanistically, NR-6226C selectively chelates iron, which is a limiting factor for pathogenic fungi during infection. As a result, NR-6226C treatment causes severe mitochondrial dysfunction, leading to formation of reactive oxygen species, metabolic reprogramming, and a severe reduction in ATP levels. Using an in vivo model for fungal infections, we show that NR-6226C significantly increases survival of Candida-infected Galleria mellonella larvae. Finally, our data indicate that NR-6226C synergizes strongly with fluconazole in inhibition of C. albicans. Taken together, NR-6226C is a promising antifungal compound that acts by chelating iron and disrupting mitochondrial functions.

• LaLone, Vernon; Aizenshtadt, Aleksandra; Goertz, John; Skottvoll, Frøydis Sved; Mota, Marco Barbero & You, Junji [Show all 15 contributors for this article] (2023). Quantitative chemometric phenotyping of three-dimensional liver organoids by Raman spectral imaging. Cell Reports Methods. 3(4). doi: 10.1016/j.crmeth.2023.100440. Full text in Research Archive Show summary

  Confocal Raman spectral imaging (RSI) enables high-content, label-free visualization of a wide range of molecules in biological specimens without sample preparation. However, reliable quantification of the deconvoluted spectra is needed. Here we develop an integrated bioanalytical methodology, qRamanomics, to qualify RSI as a tissue phantom calibrated tool for quantitative spatial chemotyping of major classes of biomolecules. Next, we apply qRamanomics to fixed 3D liver organoids generated from stem-cell-derived or primary hepatocytes to assess specimen variation and maturity. We then demonstrate the utility of qRamanomics for identifying biomolecular response signatures from a panel of liver-altering drugs, probing drug-induced compositional changes in 3D organoids followed by in situ monitoring of drug metabolism and accumulation. Quantitative chemometric phenotyping constitutes an important step in developing quantitative label-free interrogation of 3D biological specimens.

• Berg, Henriette Engen; Halldórsso, Skarphéðinn; Bakketeig, Eris Aas; Thiede, Bernd; Sandberg, Cecilie & Lundanes, Elsa [Show all 8 contributors for this article] (2022). Micro‐pillar array columns (µPAC): An efficient tool for comparing tissue and cultured cells of glioblastoma. Journal of chromatography open. ISSN 2772-3917. 2. doi: 10.1016/j.jcoa.2022.100047. Full text in Research Archive
• Kogler, Stian; Aizenshtadt, Aleksandra; Harrison, Sean; Skottvoll, Frøydis Sved; Berg, Henriette Engen & Abadpour, Shadab [Show all 14 contributors for this article] (2022). "Organ-in-a-Column" Coupled On-line with Liquid Chromatography-Mass Spectrometry. Analytical Chemistry. ISSN 0003-2700. 94(50), p. 17677–17684. doi: 10.1021/acs.analchem.2c04530. Full text in Research Archive Show summary

  Organoids, i.e., laboratory-grown organ models developed from stem cells, are emerging tools for studying organ physiology, disease modeling, and drug development. On-line analysis of organoids with mass spectrometry would provide analytical versatility and automation. To achieve these features with robust hardware, we have loaded liquid chromatography column housings with induced pluripotent stem cell (iPSC) derived liver organoids and coupled the “organ-in-a-column” units on-line with liquid chromatography-mass spectrometry (LC-MS). Liver organoids were coloaded with glass beads to achieve an even distribution of organoids throughout the column while preventing clogging. The liver organoids were interrogated “on column” with heroin, followed by on-line monitoring of the drug’s phase 1 metabolism. Enzymatic metabolism of heroin produced in the “organ-in-a-column” units was detected and monitored using a triple quadrupole MS instrument, serving as a proof-of-concept for on-line coupling of liver organoids and mass spectrometry. Taken together, the technology allows direct integration of liver organoids with LC-MS, allowing selective and automated tracking of drug metabolism over time.

• Hvinden, Ingvild Comfort; Berg, Henriette Engen; Sachse, Daniel; Skaga, Erlend; Skottvoll, Frøydis Sved & Lundanes, Elsa [Show all 10 contributors for this article] (2019). Nuclear Magnetic Resonance Spectroscopy to Identify Metabolite Biomarkers of Nonresponsiveness to Targeted Therapy in Glioblastoma Tumor Stem Cells. Journal of Proteome Research. ISSN 1535-3893. 18(5), p. 2012–2020. doi: 10.1021/acs.jproteome.8b00801. Full text in Research Archive
• Skottvoll, Frøydis Sved; Berg, Henriette Engen; Bjørseth, Kamilla; Lund, Kaja; Roos, Norbert & Bekhradnia, Sara [Show all 13 contributors for this article] (2018). Ultracentrifugation versus kit exosome isolation: nanoLC-MS and other tools reveal similar performance biomarkers, but also contaminations. Future science OA. 5(1). doi: 10.4155/fsoa-2018-0088. Full text in Research Archive Show summary

  Aim: For isolation of exosomes, differential ultracentrifugation and an isolation kit from a major vendor were compared. Materials & methods: ‘Case study’ exosomes isolated from patient-derived cells from glioblastoma multiforme and a breast cancer cell line were analyzed. Results: Transmission electron microscopy, dynamic light scattering, western blotting, and so forth, revealed comparable performance. Potential protein biomarkers for both diseases were also identified in the isolates using nanoLC–MS. Western blotting and nanoLC–MS also revealed negative exosome markers regarding both isolation approaches. Conclusion: The two isolation methods had an overall similar performance, but we hesitate to use the term ‘exosome isolation’ as impurities may be present with both isolation methods. NanoLC–MS can detect disease biomarkers in exosomes and is useful for critical assessment of exosome enrichment procedures.

• Berg, Henriette Sjånes; Sæterdal, Kristina Erikstad; Smetop, Tone; Rozenvalds, Rūdolfs; Brandtzaeg, Ole Kristian & Vehus, Tore [Show all 8 contributors for this article] (2017). Self-packed core shell nano liquid chromatography columns and silica-based monolithic trap columns for targeted proteomics. Journal of Chromatography A. ISSN 0021-9673. 1498, p. 111–119. doi: 10.1016/j.chroma.2017.03.043. Full text in Research Archive
• Wilson, Steven Ray Haakon; Vehus, Tore; Berg, Henriette Sjånes & Lundanes, Elsa (2015). Nano-LC in proteomics: Recent advances and approaches. Bioanalysis. ISSN 1757-6180. 7(14), p. 1799–1815. doi: 10.4155/bio.15.92. Full text in Research Archive

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• Bakketeig, Eris Aas; Olsen, Christine; Berg, Henriette Engen; Nyman, Tuula Anneli; Thiede, Bernd & Lundanes, Elsa [Show all 8 contributors for this article] (2021). Optimization of concatenation of fractions in comprehensive two dimensional liquid chromatography bottom-up proteomics. Full text in Research Archive Show summary

  Two dimensional liquid chromatography (2D-LC) has long been a commonly used technique in bottom-up proteomics, and is as relevant today as ever [1, 2]. To maximize the number of protein identifications, analytical chemists have strived to obtain 2D-LC systems with a high degree of orthogonality, which is needed to reach the required high peak capacities. A system utilizing reversed-phase chromatography (RP) in both column dimensions with a large difference in pH has proven to yield a higher peak capacity for peptides, even with a lower degree of orthogonality compared to other combinations [3]. The present study is based on Reubsaet, et al. [4]. The study is a comprehensive offline RPRP 2D-LC system with high pH (>9) in the first dimension and low pH (3) in the second dimension. The method’s purpose is to maximise protein identifications from one trypsinated protein sample. To achieve maximum identifications, Reubsaet incorporated the concept of concatenation of fractions. In practice, concatenation is applied through collecting the column output from the first dimension in eight numbered vials, where the 1st, 9th, 17th, … fractions are collected in the first vial, the 2nd, 10th, 18th, … are collected in the second, etc. [4]. In the present study, the fractionation scheme is examined by changing the total number of vials in which samples are concatenated, the number of fractions in each vial, and the collection time for each fraction. As the method demands high precision and is very timeconsuming, automatization is practically essential. Automatization is achieved with the spider fractionation scheme, proposed and shown by Kulak, et al.[5]. Here, a 10-port injector connects the first dimension column to each sample vial, and switches between them automatically, reducing the strain on the operator drastically, while removing human errors. The optimization of the concatenation will lead to higher numbers of identified proteins in proteomics.

• Flatval, Jonas; Berg, Henriette Engen; Lillerud, Karl Petter; Olsbye, Unni; Nielsen, Claus Jørgen & Wilson, Steven Ray Haakon [Show all 7 contributors for this article] (2020). Retention of nitramines on UiO-66 ZrMOF materials and silica-based reversed phase materials. Full text in Research Archive
• Andersen, Kari Anne; Flatval, Jonas; Mrša, Ago; Berg, Henriette Engen; Chavan, Sachin Maruti & Olsbye, Unni [Show all 8 contributors for this article] (2020). Metal organic framework material UiO-66 as a stationary phase in liquid chromatography. Full text in Research Archive Show summary

  Metal organic framework materials (MOFs) are interesting candidates for applications in multiple disciplines, where chromatography is one of the fields where possible applications might exist. The porous structure and large surface area are key features that make MOFs potential candidates for future stationary phases. In the present study, the MOF UiO-66 has been investigated as a stationary phase in a nano-liquid chromatography (LC) system. UiO-66 is composed of zirconium oxide ion nodes and benzene dicarboxylate (BDC) linkers which form a face-centred cubic structure with octahedral pores (opening 6 Å, cavity 11 Å) and tetrahedral pores (opening 6 Å, cavity 7.5 Å) in a 1+2 ratio. Figure adapted from Cliffe et al., Nature communications volume 5 (2014)1. Columns with a 100 µm inner diameter have been packed in-house and tested in a simple LC-UV system for several test substances. The UiO-66 particles pack rapidly and yield columns with low back pressure. We observe reversed phase selectivity, but our experimental data also suggest other interaction mechanisms, phosphate group adsorption to zirconium oxide nodes among them.

• Berg, Henriette Engen; Halldórsson, Skarphéðinn; Thiede, Bernd; Vik-Mo, Einar O.; Lundanes, Elsa & Wilson, Steven Ray Haakon (2020). Micro pillar array columns for comprehensive proteomics. Full text in Research Archive Show summary

  Pillar array nano liquid chromatography columns can potentially replace packed nano liquid chromatography (nLC) columns for analyses of complex samples due to high chromatographic performance and low backpressure. In our study, pillar array columns are used for the detection of potential biomarkers in Glioblastoma Multiforme (GBM), which is the most aggressive form of brain cancer in adults. Pillar array columns consist of several micropillars etched into silicon wafers using lithographic micromachining. The interest of these columns in nLC format has increased as an option to packed nLC columns as the chromatographic efficiency could outperform nLC columns packed with sub-2 µm particles while maintaining the sensitivity [1]. In contrast to packed columns, where eddy dispersion is the main source of band broadening due to irregular flow paths between the particles, the perfectly ordered pillars in pillar array columns eliminate the eddy dispersion to a minimum. The low backpressure of pillar array columns compared to that of packed columns also permits the use of exceptionally long columns, increasing the chromatographic performance further. Using pillar array columns, plate numbers over 1 million and reduced plate heights (h) even <1 µm have been achieved [2-4]. High chromatographic performance is especially important in comprehensive proteomics. Pre-fractionation (using e.g. gel electrophoresis) is often added in proteomic protocols to increase the throughput [5]. However, performing pre-fractionation can be time-consuming in addition to the highly increased instrument time required. Recently, a micro-Chip pillar array nLC column (µPACTM) compatible with standard nLC instrumentation has been commercialized (Figure 1) [6]. Our question was; could the use of µPAC nLC columns reduce the need for pre-fractionation in comprehensive proteomics of GBM biopsies?

• Berg, Henriette Engen; Hvinden, Ingvild Comfort; Sachse, Daniel; Skaga, Erlend; Lundanes, Elsa & Sandberg, Cecilie [Show all 9 contributors for this article] (2020). Observation of brain cancer cells’ molecular responses to chemotherapy. Full text in Research Archive
• Wilson, Steven Ray Haakon; Berg, Henriette Engen; Røberg-Larsen, Hanne & Lundanes, Elsa (2019). Hyphenations of one-dimensional capillary liquid chromatography with mass spectrometry: state-of-the-art applications. In Tranchida, Peter & Mondello, Luigi (Ed.), Hyphenations of Capillary Chromatography with Mass Spectrometry. Elsevier. ISSN 9780128096383. p. 319–358. Full text in Research Archive
• Hassine, Esma Ben; Berg, Henriette Engen; Brandtzaeg, Ole Kristian; Vehus, Tore; Wilson, Steven Ray Haakon & Lundanes, Elsa (2018). Capillary poly(styrene-co-octadecene-co-divinylbenzene) monolithic columns. Full text in Research Archive
• Berg, Henriette Sjånes; Bjørseth, Kamilla; Sæterdal, Kristina Erikstad; Smetop, Tone; Skottvoll, Frøydis Sved & Vehus, Tore [Show all 8 contributors for this article] (2018). Evaluation of isolation methods of glioma exosomes for biomarker discovery. Full text in Research Archive Show summary

  Gliomas are the most common form of brain cancer, where the sub-group glioblastoma multiforme (GBM) is the most aggressive and the most common in adults [1]. For diagnostic, prognostic, and treatment monitoring, fast and reliable analytical methods for detection of glioblastoma tumors are essential. Non-invasive monitoring of circulating biomarkers in blood (liquid biopsy) is a desirable possibility [2]. Nano LC-MS can provide the high sensitivity, selectivity and low false positive rate needed for the proteomic analysis of exosomes, which are extracellular vesicles released from the tumor and into the bloodstream. We have optimized the packing of 50 µm capillaries (2.6 µm C18 core-shell particles) with peak capacities comparable to similar commercial nano-LC columns (75 µm ID) for peptide separations of minute samples (e.g. exosomes). These columns have previously been successfully used for the targeted detection of CYP27a (a potential breast cancer biomarker) in the MDA-MB-231 cell line. In the present study, these in-house packed columns have been applied for proteins in exosomes isolated from GBM cell culture medium. The aim of this study was to compare isolation methods of GMB exosomes for biomarker discovery and study proteins related to GBM in exosomes. Ultracentrifugation (“golden standard” in exosome isolation) was compared to a Total Exosome Isolation Reagent from Invitrogen (Thermo Fisher Scientific) regarding sample volume, total protein amount, purity, and the presence of exosome markers and GBM biomarker candidates. References 1. Molina, J.R., Y. Hayashi, C. Stephens, and M.M. Georgescu, Invasive Glioblastoma Cells Acquire Stemness and Increased Akt Activation. Neoplasia. 12 (2010) 453-U37. 2. Best, M.G., N. Sol, S. Zijl, J.C. Reijneveld, P. Wesseling, and T. Wurdinger, Liquid biopsies in patients with diffuse glioma. Acta Neuropathologica. 129 (2015) 849-865.

• Hvinden, Ingvild Comfort; Rise, Frode; Berg, Henriette Engen; Lundanes, Elsa & Wilson, Steven Ray Haakon (2018). Approaches to untargeted metabolomics of glioblastoma: NMR and MS. Full text in Research Archive
• Berg, Henriette Engen; Skottvoll, Frøydis Sved; Bjørseth, Kamilla; Sæterdal, Kristina Erikstad; Brandtzaeg, Ole Kristian & Vehus, Tore [Show all 11 contributors for this article] (2018). Development of nanoLC column technology for proteomic studies. Full text in Research Archive Show summary

  Background NanoLC has emerged as a major technique in proteomics due to improved sensitivity, which enables analysis of small sample volumes and low concentrations. In our group (Bioanalytical chemistry, BACH) we focus on the development of column technology, including porous layer open tubular (PLOT) columns and self-packing of columns for proteomic applications. Methods The PLOT columns were used for both on-line digestion (enzyme reactors) and separations (10 µm ID, PS-DVB with ODS). Enzyme reactors (20 µm ID and multi-PLOT columns (~8 µm ID)) were immobilized with trypsin and Lys-C for protein digestion. We also compared self-packed columns of 50 µm ID (2.6 µm C18 core-shell particles) to a commercial column (75 µm ID). The columns were used for detection of CYP27a1 in MDA-MB-231 (breast cancer) cells, and biomarker candidates in MDA-MB-231 and glioblastoma multiforme (brain cancer) exosomes. For exosome isolation (cell culture medium), ultracentrifugation (“golden standard”) was compared to a Total Exosome Isolation Reagent from Thermo Fisher regarding protein yield and purity. Results Our PLOT columns were successfully employed for proteins, metabolites and peptides with attogram detection limits and peak capacities around 250 [1]. The enzyme reactors provided sufficient digestion in ~5 minutes compared to overnight digestions (common in off-line protocols) [2]. Furthermore, a quantitative method of the neurotoxin ricin was developed using the multi-PLOT to reduce manual sample handling [3] . The self-packed columns obtained peak capacities comparable to the commercial nanoLC column for peptide separations [4]. The self-packed columns were used for the targeted detection of CYP27A1 (potential breast cancer biomarker) in MDA-MB-231 cells. In the recent exosome study, exosomes were present and biomarker candidates were identified. However, the characterization techniques are in our hands not satisfactory. Conclusions We have successfully developed sensitive nanoLC column formats for proteomic applications.

• Skottvoll, Frøydis Sved; Lund, Kaja; Røberg-Larsen, Hanne; Berg, Henriette Sjånes; Thiede, Bernd & Lundanes, Elsa [Show all 7 contributors for this article] (2017). Diagnostic potential of exosomes: The purification issue. Full text in Research Archive
• Berg, Henriette Sjånes; Vehus, Tore; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). Optimization of in-house packed nano-LC columns for peptide separations. Full text in Research Archive
• Berg, Henriette Engen; Vehus, Tore; Lundanes, Elsa & Wilson, Steven Ray Haakon (2016). Optimization of in-house packed nano-LC columns for peptide separations in clinical medicine. Full text in Research Archive Show summary

  Early detection of biomarkers for diseases, such as cancer, is one of the most challenging and important goals in clinical medicine [1]. In modern protein analysis, mass spectrometry (MS) with electrospray ionization (ESI) has increased in popularity (compared to typical immunoassay methods) because of the sensitivity, universality, and low false positive rate. However, the MS is dependent of chromatographic separation of biological samples to lower the complexity (reduced number of analytes for the MS to handle per time unit). In this regard, the goal is an effective separation with high peak capacity (for gradient elution) and sensitivity to be able to detect possible biomarkers in or low concentrations and/or low sample volumes. Nano-LC columns can provide high sensitivity because of the low inner diameter (ID) and compatibility with ESI-MS, but the scarcity of commercial <75 µm ID packed columns limits the separation principles available. In pre-clinical research, self-packing of nano-LC columns can increase the flexibility in assessing (novel) separation materials to a low cost. In the present study, the packing process has been optimized to obtain sensitive and efficient packed columns (50 µm ID) for peptide separations with comparable performance to commercial nano-LC columns. In addition, PicoFrit columns with integrated emitter from New Objective (Woburn, MA, USA) will be examined to evaluate the potential reduction in extra-column band broadening.

• Almvik, Marit; Gran, Hanne Marit; Berg, Henriette Engen; Guldberg, Ivo Havranek & Stuveseth, Kari (2026). Plantetoksiner i næringsmidler 2025. Rapport fra overvåkings- og kartleggingsprogram. Mattilsynet og NIBIO. ISSN 9788293607274. doi: https:/www.mattilsynet.no/mat-og-drikke/uonskede-stoffer-i-mat/biologiske-gifter/analyser-av-plantetoksiner-i-naeringsmidler. Full text in Research Archive Show summary

  Mattilsynet utfører årlig offentlig kontroll av fremmedstoffer i næringsmidler. I samarbeid med NIBIO undersøkes nivåene av naturlige giftstoffer (plantetoksiner) i mat. Hensikten med overvåkingsprogrammet er først og fremst å overvåke nivået av plantetoksiner for å sikre at forbrukeren ikke utsettes for noe som kan utgjøre en helsefare. Overvåkingen skal også bidra til å sikre at næringsmiddelvirksomheter etterlever regelverket, slik at plantetoksiner ikke overskrider gjeldende grenseverdier. Rapporten presenterer resultater fra 50 prøver som ble hentet fra det norske markedet i 2025. Dette var: • 5 sorghumprøver, 5 teffprøver og 5 barnegrøtprøver som ble analysert for tropane alkaloider, • 5 prøver av spisskummen, 5 urtete-prøver og 5 prøver av urtekrydder med oregano som ble analysert for pyrrolizidinalkaloider, • 10 prøver av bakevarer med valmuefrø ble analysert for opiumalkaloider, og • 10 linfrøprøver ble analysert for cyanogene glykosider (hydrogencyanid) Resultatet av analysene; • Vi påviste ikke tropane alkaloider i noen prøver. • Det ble funnet tre prøver over grenseverdi for pyrrolizidinalkaloider. To av disse prøvene var fra tørket oregano og én var fra urtete av sitronmelisse. Kun urteteen var en overskridelse av grenseverdien etter fratrekk for usikkerheten. • Alle prøver av bakevarer med valmuefrø hadde funn av opiumalkaloider under grenseverdien. • Tre prøver av linfrø inneholdt hydrogencyanid over grenseverdien. Funn over grenseverdi blir fulgt opp overfor importør/virksomheten av produktet.

• Almvik, Marit; Gran, Hanne Marit; Berg, Henriette Engen & Stuveseth, Kari (2024). Plantetoksiner i næringsmidler 2023. Mattilsynet og NIBIO. ISSN 9788293607168. Full text in Research Archive
• Almvik, Marit; Stuveseth, Kari; Berg, Henriette Engen; Senneset, Gunvor; Vartdal, Ellen & Alsbirij, Mohammad [Show all 7 contributors for this article] (2024). Funn av rester av plantevernmidler i organiske gjødselvarer i 2023 - Overvåking- og kartleggingsprogram. NIBIO. ISSN 9788217035213. Full text in Research Archive Show summary

  Rapporten presenterer resultatene fra et Overvåking- og kartleggingsprogram for rester av plantevernmidler i organiske gjødselvarer i 2023, på oppdrag for Mattilsynet. Det ble samlet inn og analysert 60 prøver organiske gjødselvarer, hovedsakelig basert på husdyrgjødsel, kjøkken- og matavfall, hage- og parkavfall, halm og kompost. Det var flest funn i pelleterte produkter, mens dyrkingsmedium/kompost inneholdt minst rester av plantevernmidler. Totalt 32 ulike plantevernmidler og metabolitter av plantevernmidler ble påvist i ulike typer organiske gjødselvarer. Funnkonsentrasjonene var generelt lave (3- 660 μg/kg). Kun 7 plantevernmidler ble påvist i konsentrasjoner over 100 μg/kg. Foruten ugrasmiddelet clopyralid, som var det hyppigst påviste stoffet (19 av 60 prøver), ble plantevekstregulatoren /stråforkorteren chlormequat påvist i 12 av 60 prøver, mens soppmiddelet fluopyram ble påvist i 8 av 60 prøver. Soppmidlene imazalil og pyrimethanil ble påvist i 8 av 60 prøver. For yrkesutøvere som bruker organiske gjødselvarer kan det være problematisk dersom det blir gjort funn av plantevernmidler i matvaren som ikke er godkjent brukt i kulturen eller dersom det blir gjort funn i økologiske produkter. Gitt de lave konsentrasjonene som er påvist i denne kartleggingen, så vil nivået i vegetabilske matvarer etter bruk av disse gjødselvarene sannsynligvis være under tillatte grenseverdier (MRL). Opptaksstudier i matplanter og modellberegninger ville gitt større sikkerhet i konklusjonen. Anbefalingen er å utvikle mer kunnskap og modeller for beregning av opptak av ulike typer plantevernmidler i matplanter som grunnlag for å sette grenseverdier og kunne gjøre en helhetlig risikovurdering.

• Almvik, Marit; Gran, Hanne Marit; Berg, Henriette Engen; Stuveseth, Kari; Senneset, Gunvor & Lang, Kathinka (2023). Analyser av plantetoksiner i næringsmidler i 2022. Mattilsynet og NIBIO. ISSN 9788293607144. Full text in Research Archive Show summary

  I 2022 ble totalt 30 prøver analysert for plantetoksiner. Av disse var det 15 prøver av barnegrøt, skumpinner og frokostblandinger som ble analysert for tropane alkaloider, i form av atropin og skopolamin. Videre ble 15 prøver av te, urtekrydder og bakeblandinger analysert for pyrrolizidinalkaloider. Det ble ikke påvist hverken atropin eller skopolamin i barnegrøt, skumpinner eller frokostblanding. Det ble ikke påvist pyrrolizidinalkaloider i bakeblandinger eller i grønn te. Det ble påvist pyrrolizidinalkaloider i begge urtekrydderne og i èn prøve urtete. En prøve urteblanding og en prøve urtete hadde nivå over nåværende grenseverdi.

• Berg, Henriette Engen; Wilson, Steven Ray Haakon; Lundanes, Elsa; Thiede, Bernd & Vik-Mo, Einar Osland (2022). Exploring miniaturized chromatography formats and sample preparation methods for shotgun proteomics in limited biological samples. Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Oslo. Full text in Research Archive Show summary

  A significant challenge in medical diagnostics is the development of simple but efficient tools for the detection/quantification of several biomarkers simultaneously using non-invasive sampling techniques. In this regard, the analysis of proteins (proteomics) is essential for understanding cellular processes and biomarker discovery. However, proteins vary greatly in terms of concentration levels and chemical properties in biological materials. Further, low sample sizes of modern biological models (e.g., patient-derived cell cultures, exosomes, and organoids) remain a big analytical challenge. The present work has focused on the brain cancer glioblastoma, which is in great need of increased knowledge and non-invasive sampling techniques. In addition, human organoids, which could act as a future in vitro model for disease modeling and personalized medicine, have been investigated. We have used high-resolution mass spectrometry for protein identification, exploring a selection of miniaturized liquid chromatography formats (for separation) and sample preparation techniques. By implementing these techniques, we have been able to study exosomes, 2D/3D cell cultures, and organoids, identifying over 6300 proteins in a single run using less than 5 µg of protein. The work has provided important insight into the possibilities and challenges of several novel models. It represents a development toward deeper proteomic profiling focusing on maintaining a high protein yield and time efficiency.

• Bakketeig, Eris Aas; Wilson, Steven Ray Haakon; Lundanes, Elsa; Berg, Henriette Engen; Olsen, Christine & Reubsaet, Leon [Show all 8 contributors for this article] (2021). The setup and optimization of a complete global proteomics two-dimensional liquid chromatography system, using Spider Fractionation. Universitetet i Oslo. Full text in Research Archive
• Flatval, Jonas; Lundanes, Elsa; Wilson, Steven Ray Haakon; Olsbye, Unni; Nielsen, Claus Jørgen & Berg, Henriette Engen (2020). Retention of nitramines on silica-based reversed phase materials and UiO-66 MOF materials. Universitetet i Oslo. Full text in Research Archive Show summary

  Capturing and storing of CO2 can reduce the emissions of CO2 in the atmosphere. However, such facilities may emit amines that can be transformed into the potentially carcinogenic nitramines dimethylnitramine (DMA-NO2), monoethanolnitramine (MEA-NO2) and monomethylnitramine (MMA-NO2) which may be released into the environment. Presently, methods for trace determination of these compounds are lacking. The goal of the study was to find a material that can give sufficient retention to provide an enrichment of the nitramines before liquid chromatography electrospray ionization-mass spectrometry determination. The retention of the nitramines was examined on various C18 materials and the metal-organic frameworks UiO-66 and UiO-66 1,4-benzenedicarboxylate-NH2 (UiO-66-NH2), which were packed in 100 µm inner diameter columns. Of the tested materials, UiO-66-NH2 showed the highest retention factors for the nitramines. UiO-66-NH2 with 0.1% formic acid adjusted to pH 7 as mobile phase gave the best compromise of retention factors for DMA-NO2 and MEA-NO2, as the intended liquid chromatography-mass spectrometry method was evaluated for DMA-NO2 and MEA-NO2 only. MMA-NO2 had the highest retention factor on UiO-66-NH2 with 0.05% dibutylamine in the mobile phase. In conclusion, the retention factors achieved were in general higher on the UiO-66 materials than on the C18 materials. However, the retention obtained is probably not large enough to give limit of quantification down to 4 ng/L, albeit, not tested, due to extraordinary circumstances.

• Andersen, Kari Anne; Lundanes, Elsa; Berg, Henriette Engen; Wilson, Steven Ray Haakon; Chavan, Sachin Maruti & Lillerud, Karl Petter [Show all 7 contributors for this article] (2020). UiO-66 metal-organic framework materials as stationary phases in liquid chromatography. Universitetet i Oslo. Full text in Research Archive
• Hassine, Esma Ben; Lundanes, Elsa; Wilson, Steven Ray Haakon; Vehus, Tore; Brandtzaeg, Ole Kristian & Berg, Henriette Engen (2018). Capillary poly(styrene-co-octadecene-co-divinylbenzene) monolithic trap columns for bioanalytical analysis. Universitetet i Oslo. Full text in Research Archive Show summary

  The increasing demand for faster and more efficient separations for biological samples have driven organic polymer-based monolithic columns back into the spotlight. The nature of the monolithic structure allows the use of higher flow rates without increasing the system backpressure. They are also easier to contain inside the column body, opposed to particle packed columns, which are held in place by frits. These are some of the advantages that monolithic columns offer compared to particle packed columns. Poly(styrene-co-octadecene-co-divinylbenzene) (PS-OD-DVB) monolithic columns have been prepared and characterized using the neuropeptide oxytocin, “the love hormone” as test compound. The columns, 50 µm inner diameter x 100 mm in length, were to be used as trap columns in a miniaturized liquid chromatography-mass spectrometry (LC-MS) column switching system for bottom-up proteomics analysis. The monolithic PS-OD-DVB columns were prepared in situ (inside the fused silica capillary), using a polymerization mixture consisting of an initiator (lauroyl peroxide), a crosslinker (divinylbenzene), monomers (styrene and 1-octadecene), a good porogen (N,N-dimethylformamide (DMF)) and a bad porogen (1-decanol). Polymerization time, polymerization temperature, initiator concentration, and monomer to porogen ratios were investigated in order to obtain a monolithic structure with a high surface area and good permeability. The best PS-OD-DVB monolithic column was prepared using a mixture of 1.9% lauroyl peroxide (weight percentage of monomer amount), 14.2% divinylbenzene, 15.2% monomers, 11.9% DMF and 57.5% 1-decanol. The column was polymerized for one hour at 73°C and gave a plate height of 62 µm, a backpressure of 23 bar at a flow rate of 500 nL/min with a mobile phase consisting of 20% B (acetonitrile (ACN), water, formic acid (FA), 80/20/0.1, v/v/v) and 80% A (water with 0.1% (v/v) FA) and a retention time repeatability of 2.6% (relative standard deviation). The repeatability of the columns made by various individuals was satisfactory. However, when preparing twenty-one columns by the same individual, the repeatability revealed to be questionable. Hence, further improvements in the polymerization procedure do seem necessary and might be able to enhance the repeatability of the columns.

• Amundsen, Sunniva Furre; Wilson, Steven Ray Haakon; Berg, Henriette Engen; Røberg-Larsen, Hanne & Lundanes, Elsa (2018). Online entrapment of epitope-containing peptides from integrins using immobilized antibodies. Universitetet i Oslo. Full text in Research Archive
• 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. Full text in Research Archive Show summary

  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.

• Skottvoll, Frøydis Sved; Berg, Henriette Engen; Lund, Kaja; Røberg-Larsen, Hanne; Wilson, Steven Ray Haakon & Lundanes, Elsa (2017). Critical evaluation of isolation and characterization techniques of breast cancer exosomes. Universitetet i Oslo. Full text in Research Archive Show summary

  Exosomes represent a distinct class of extracellular vesicles of endocytic origin secreted by multiple cell types, including tumour cells. An increased release of exosomes, which appears to be a rich source of biomarkers, has been reported from tumour cells. However, current strategies concerning the isolation (and characterization) of exosomes from fluids differ significantly and no consensus method is established. The goal of this work was to evaluate two different exosome isolation methods with two different breast cancer cell lines in culture: differential ultracentrifugation and commercial isolation kit. Evaluation was done using a bicinchoninic acid assay (protein concentration), transmission electron microscopy (morphology), dynamic light scattering (hydrodynamic size), western blotting (targeted protein exosome markers) and nano liquid chromatography tandem mass spectrometry (comprehensive protein identification). The characterization techniques confirmed the isolation of exosomes with both isolation kit and ultracentrifugation. However, the isolated samples did contain contaminations, and there was a clear difference in the protein amount, particle size and populations identified with the two isolation methods. In addition, the majority of the characterization techniques provided poor repeatability, reproducibility and/or demanded extensive optimization. The evaluation showed that the exosome isolation procedures used in this thesis appear to be far from mature. Additionally, the majority of the characterization techniques used in this study provided challenges.

• Berg, Henriette Sjånes; Lundanes, Elsa; Wilson, Steven Ray Haakon & Vehus, Tore (2016). Optimization of in-house packing of nano liquid chromatography columns - How to pack low-cost nano liquid chromatography columns? Universitetet i Oslo. Full text in Research Archive Show summary

  Liquid chromatography-mass spectrometry (LC-MS) approaches for measurement of biomarkers are increasing in popularity due to the selectivity and sensitivity. To match the detection limits of the immunoassay approaches (such as enzyme-linked immunosorbent assay (ELISA) and Western Blot (WB)), LC columns with narrow inner diameter are preferable. The goal of this work was to establish a simple and low cost slurry packing procedure to obtain 50 µm inner diameter (ID) x 150 mm particle packed nanoLC columns with comparable performance to a 75 µm ID x 150 mm commercial nanoLC column. Slurry packing with 2.6 µm solid-core reversed phase particles was performed with an in-house made pressure bomb system (< 200 bar). Column efficiency was measured as peak capacity (number of peaks separated in a gradient window, PC), calculated using peptides from tryptic digest of human serum albumin (HSA). To maintain sedimentation of particles, heat or magnetic stirring was needed. 80/20 % acetonitrile (ACN)/water as slurry solvent was found to give both the fastest packing and the most efficient columns measured as PC (89 ± 11 at 10 % of the peak height for columns packed with magnetic stirring). Nevertheless, the column performance was quite similar for all slurry solvents and packing approaches. “Pico Frit” column housings from New Objective and two frit-making procedures (polymerization and sintering of silica particles) for standard column housings were compared, but none outperformed the others. The PC of the commercial column packed with the same material as the in-house packed columns, was approximately 30 % higher than the best performing in-house packed column (102 vs 136). However, the retention time repeatability between replicates was equal to the commercial column for most columns packed with 80/20 % ACN/water. In conclusion, this work presents a fast and low cost packing procedure of nanoLC columns with similar performance to commercial nanoLC columns.

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