Ellen Hanne Skorbakk

• Børud, Bente; Anonsen, Jan Haug; Viburiene, Raimonda; Cohen, Ellen Hanne; Samuelsen, Anne Berit C. & Koomey, Michael (2014). Extended glycan diversity in a bacterial protein glycosylation system linked to allelic polymorphisms and minimal genetic alterations in a glycosyltransferase gene. Molecular Microbiology.  ISSN 0950-382X.  Volume 94(3), s 688- 699 . doi: 10.1111/mmi.12789 Show summary

  Glycans manifest in conjunction with the broad spectrum O-linked protein glycosylation in species within the genus Neisseria display intra- and interstrain diversity. Variability in glycan structure and antigenicity are attributable to differences in the content and expression status of glycan synthesis genes. Given the high degree of standing allelic polymorphisms in these genes, the level of glycan diversity may exceed that currently defined. Here, we identify unique protein-associated disaccharide glycoforms that carry N-acetylglucosamine (GlcNAc) at their non-reducing end. This altered structure was correlated with allelic variants of pglH whose product was previously demonstrated to be responsible for the expression of glucose (Glc)-containing disaccharides. Allele comparisons and site-specific mutagenesis showed that the presence of a single residue, alanine at position 303 in place of a glutamine, was sufficient for GlcNAc versus Glc incorporation. Phylogenetic analyses revealed that GlcNAc-containing disaccharides may be widely distributed within the pgl systems of Neisseria particularly in strains of N. meningitidis. Although analogous minimal structural alterations in glycosyltransferases have been documented in association with lipopolysaccharide and capsular polysaccharide variability, this appears to be the first example in which such changes have been implicated in glycan diversification within a bacterial protein glycosylation system.

• Brüll, L.; Huang, Z.B.; Thomas-Oates, Jane E.; Paulsen, Berit Smestad; Cohen, Ellen Hanne & Michaelsen, Terje Einar (2000). Studies of polysaccharides from three edible species of Nostoc (cyanobacteria) with different colony morphologies: Structural characterization and effect on the complement system of polysaccharides fro Nostoc commune. Journal of Phycology.  ISSN 0022-3646.  36(5), s 871- 881
• Samuelsen, Anne Berit; Cohen, Ellen Hanne; Paulsen, Berit Smestad; Brüll, Lars P. & Thomas-Oates, Jane E. (1999). Structural studies of a heteroxylan from Plantago major L. seeds by partial hydrolysis, HPAEC-PAD, methylation and GC-MS, ESMS and ESMS/MS. Carbohydrate Research.  ISSN 0008-6215.  315, s 312- 318 Show summary

  The seed mucilage from Plantago major L. contains acidic heteroxylan polysaccharides. For further structural analysis, oligosaccharides were generated by partial acid hydrolysis and then isolated by high-pH anion-exchange chromatography (HPAEC-PAD). Each HPAEC fraction was shown by ESMS to contain one major oligosaccharide and several minor components. Partial structures of the oligosaccharides were determined using GC-MS, ESMS and ES tandem mass spectrometry (ESMS/MS). A (1->4)-linked xylan trisaccharide and (1->3)-linked xylan oligosaccharides with DP 6-11 suggested that the backbone of the heteroxylan polysaccharide consisted of blocks of (1->4)-linked and (1->3)-linked Xylp residues. A (1->2)-linked Xylp disaccharide and a branched tetrasaccharide were also found, revealing that single Xylp residues are linked to the O-2 of some of the (1->4)-linked Xylp residues in the backbone. In addition, our resutls confirm the presence of side chains consisting of the disaccharide GlcpA-(1->3)-Araf.

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• Ho, Giang Thanh Thi; Zou, Yuan-Feng; Wangensteen, Helle; Cohen, Ellen Hanne & Barsett, Hilde (2015). Immunomodulating pectins from elderberries.
• Ho, Giang Thanh Thi; Zou, Yuan-Feng; Wangensteen, Helle; Cohen, Ellen Hanne & Barsett, Hilde (2015). Immunomodulating pectins from elderberries.
• Ho, Giang Thanh Thi; Ahmed, A; Zou, Yuanfeng; Wangensteen, Helle; Cohen, Ellen Hanne & Barsett, Hilde (2015). Structure-activity relationship of immunomodulating pectins from elderberries.
• Samuelsen, Anne Berit; Cohen, Ellen Hanne & Knutsen, Svein Halvor (2002). Plantago afra seed polysaccharides.
• Sogn, Cecilie; Diallo, Drissa; Paulsen, Berit Smestad; Cohen, Ellen Hanne; Michaelsen, Terje Einar & Tønnesen, Finn (2001). Analysis of polysaccharides from the root of Vernonia kotchyana, a medicinal plant from Mali.
• Barsett, Hilde; Langseter, Anne Marie; Kristiansen, Gine; Cohen, Ellen Hanne & Michaelsen, Terje Einar (2001). Polysaccharides from root preparations of Echinacea angustifolia, structure and biological activity. Show summary

  Studies on biological active carbohydrate fractions from three commercial products: «Echinagard», containing squeezed sap of the aerial parts of Echinacea purpurea, «Tinctura echinaceae», a 50% ethanolic extract of the root of Echinacea angustifolia and «Echinaforce», a 58% ethanolic extract of the whole plant of Echinacea purpurea (95% herb, 5% root), have shown that carbohydrate fractions with anti-complementary activity isolated from E. purpurea preparations are different from the anti-complementary active carbohydrate fractions from the E. angustifolia preparation. Monosaccharide analysis after methanolysis showed that the E. angustifolia preparation contains much more rhamnose and less galactose than active fractions from the E. purpurea preparations. Methylation analysis showed that «Tinctura echinaceae» contains terminal rhamnose, 1,3- and 1,3,6-linked glucose and 1,5- and 1,3,5-linked arabinose not found in the E. purpurea fractions. All the fractions contained 2,1-linked fructose, terminal and 1,6-linked glucose and terminal arabinose. The E. purpurea fractions contained terminal and 1,6-linked galactose, terminal xylose and 1,2-linked arabinose. High molecular weight fractions had much higher anti-complementary activity than the low molecular weight fractions. Further isolation and fractionation of polysaccharides from the root of E. angustifolia were done by ion exchange chromatography and gelfiltration. Anti-complementary activity was determined and structural investigations performed by GC-MS after methylation.

• Sogn, Cecilie; Diallo, Drissa; Paulsen, Berit Smestad; Cohen, Ellen Hanne & Michaelsen, Terje Einar (2000). Analysis of polysaccharides from the root of Vernonia kotchyana.
• Sogn, Cecilie; Diallo, Drissa; Paulsen, Berit Smestad; Cohen, Ellen Hanne & Michaelsen, Terje Einar (2000). Analysis of polysaccharides from the root of Vernonia kotchyana, a medicinal plant form Mali.
• Barsett, Hilde; Langseter, Anne Marie; Kristiansen, Gine; Cohen, Ellen Hanne & Michaelsen, Terje Einar (2000). Polysaccharides from root preparations of Echinacea angustifolia, structure and biological activity.
• Barsett, Hilde; Langseter, Anne Marie; Kristiansen, Gine; Cohen, Ellen Hanne & Michaelsen, Terje Einar (2000). Polysaccharides from root preparations of Echinacea angustifolia, structure and biological activity.
• Sogn, Cecilie; Diallo, Drissa; Paulsen, Berit Smestad; Cohen, Ellen Hanne; Michaelsen, Terje Einar & Tønnesen, Finn (1999). Analysis of polysaccharides from the root of Vernonia kotschyana, a medicinal plant from Mali.
• Barsett, Hilde; Thingstad, Torunn; Cohen, Ellen Hanne; Aslaksen, Torun Helene & Haavik, Svein (1997). Lectin binding properties of human carcinoma-associated antigens. Glycoconjugate Journal.  ISSN 0282-0080.  14
• Barsett, Hilde; Thingstad, Torunn; Cohen, Ellen Hanne; Aslaksen, Torun Helene & Haavik, Svein (1997). Lectin binding properties of human carcinoma-associated antigens.
• Barsett, Hilde; Thingstad, Torunn; Cohen, Ellen Hanne; Aslaksen, Torun Helene & Haavik, Svein (1997). Undersøkelse av humane carcinoma-relaterte antigeners lektinbindende egenskaper.
• Cohen, Ellen Hanne; Barsett, Hilde; Thingstad, Torunn & Haavik, Svein (1996). Characterization of O-linked oligosaccharides on mucin-type glycoproteins by HPAEC-PAD.
• Samuelsen, Anne Berit; Cohen, Ellen Hanne; Paulsen, Berit Smestad & Wold, Jens Krisitian (1995). Structural studies of a pectic polysaccharide from Plantago major L. Show summary

  The leaves of large plantain (Plantago major L.) are used for wound healing in the traditional medicine. The effect might be due to biologically active polysaccharides. A pectin, PMII with anti-complemetary activity has been isolated from the leaves by water extraction and ion exchange chromatography. Oligosaccharides were isolated from PMII by weak acid hydrolysis and separation by SEC and HPAEC-PAD. The isolated oligosaccharides were desalted, reduced and methylated. GC-MS analysis of the partially methylated alditol acetates has bee used to reveal the structure of the oligosaccharides. Oligosaccharides consisting of galacturonic acid and rhamnose with dp 3-5 and a series of 1,4 linked galacturonic acid oligosaccharides of dp 4-10 were isolated.

• Samuelsen, Anne Berit; Cohen, Ellen Hanne; Paulsen, Berit Smestad & Wold, Jens Krisitian (1995). Structural sutdies of a pectic polysaccharide from Plantago major L. using HPAEC-PAD analysis.
• Samuelsen, Anne Berit; Knutsen, Svein Halvor; Cohen, Ellen Hanne; Paulsen, Berit Smestad & Wold, Jens Krisitian (1995). Structural studies of a pectic polysaccharide from Plantago major L.
• Malterud, Karl Egil; Brennbakk, Mona Moxness; Cohen, Ellen Hanne & Opheim, Kari (1987). Phenols from the sapwood of rowan (Sorbus aucuparia).
• Malterud, Karl Egil; Brennbakk, Mona Moxness & Cohen, Ellen Hanne (1986). Antimikrobielle substanser i ved av selje og rogn.

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