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M Bernabé

Publications and source records attributed to M Bernabé.

32 records · Page 2Linked to original sources
PubMed1995

Structural analysis of the O-antigen of the lipopolysaccharide of Rhizobium tropici CIAT899.

The structure of the O-antigen chain of the lipopolysaccharide isolated from Rhizobium tropici CIAT899, by the phenol-water procedure, and recovered from the phenol layer, has been investigated by hydrolysis, methylation analysis and 1D and 2D 1H and 13C NMR spectroscopy of the complete polysaccharide and of oligosaccharides obtained by partial hydrolysis. The O-antigen has the repeating unit [formula: see text]

Carbohydrate Sequence↗
PubMed1994

Structural studies of fungal cell-wall polysaccharides from two strains of Talaromyces flavus.

The water-soluble cell-wall polysaccharides isolated from strains CBS 352.72 and 310.38 of Talaromyces flavus have been investigated by chemical analyses and NMR studies. Two different skeletons coexist, having the structures: [formula:see text]. The small differences between the polysaccharides isolated from both strains are probably due to slight diminution of branching in strain 352.72, as compared with strain 310.38.

Carbohydrate Sequence↗
PubMed1993

Chemical structure and conformational features of cell-wall polysaccharides isolated from Aphanoascus mephitalus and related species.

The structures of cell-wall mannans isolated from Aphanoascus mephitalus, A. fulvescens, A. verrucosus, and A. reticulisporus have been investigated by chemical analyses and 1D and 2D 1H and 13C NMR techniques. It was found that all of them consists of a relatively simple comb-like structure of the disaccharide repeating block [-->6)-[alpha-Manp-(1-->2)]-alpha-Manp-(1-->]. The conformations around the alpha-(1-->2) and alpha-(1-->6) linkages in these kinds of polymers were also studied by using molecular mechanics and dynamics calculations, together with NOE data. The results are similar to those found within the oligosaccharide chains of glycoproteins, with a well-defined conformation for the alpha-(1-->2) linkage and a certain restriction around the alpha-(1-->6) bonding imposed by the 2-substitution.

Ascomycota↗
PubMed1993

Stereochemical course and structure of the products of the enzymic action of endo-1,3-1,4-beta-D-glucan 4-glucanohydrolase from Bacillus licheniformis.

The stereochemical course of the reaction catalysed by endo-1,3-1,4-beta-D-glucan 4-glucanohydrolase (EC 3.2.1.73) has been determined by 1H n.m.r. The enzyme-catalysed hydrolysis of barley beta-glucan proceeds with overall retention of the anomeric configuration, indicating that the enzyme operates through a double-displacement mechanism. The structures of the final oligosaccharide products, 3-beta-O-cellobiosyl D-glucopyranoside and 3-beta-O-cellotriosyl D-glucopyranoside, have been completely assigned by 1H- and 13C-n.m.r. spectroscopy.

Bacillus↗
PubMed1993

Differences in cell wall polysaccharides of several species of Eupenicillium.

A beta-(1-5)-galactofuran was isolated and characterized from fraction F1S (alkali- and water-soluble) of the cell wall of most of the species of Eupenicillium. In E. cryptum, E. euglaucum and E. nepalense the galactan contained galactofuranose with different linkages in addition to beta-(1-5). Fraction F1I (alkali-soluble, water-insoluble) was an alpha-glucan in certain species while in others it was a beta-glucan. Xylose was detected in some species in F1I or in F3 (alkali-soluble at 70 degrees C). The most abundant fraction (F4), resistant to the alkali treatment, was a beta-glucan-chitin complex. Excepting this component, the beta-(1-5)-galactofuran was the polysaccharide which appeared more frequently in the cell wall of species of Eupenicillium and it may have chemotaxonomic relevance.

Carbohydrates↗
PubMed1993

Syntheses and insulin-like activity of phosphorylated galactose derivatives.

The syntheses of the poly-phosphorylated galactosides 6, 8, 10, 13, 16, and 20, isolated as sodium salts, have been performed. The non-phosphorylated disaccharide 17 and trisaccharide 21 have been prepared via glycosylation of the 2-(trimethylsilyl)ethyl galactosides 3 and 2, respectively, and subsequent complete deprotection. Preliminary insulin-like activity of the phosphorylated derivatives is reported.

Cells, Cultured↗
PubMed1992

Chemical and structural similarities in wall polysaccharides of some Penicillium, Eupenicillium and Aspergillus species.

Various fractions were extracted from cell-wall material of Eupenicillium crustaceum, Penicillium brevi-compactum, P. decumbens, Aspergillus flavipes and A. ochraceus. The most characteristic fractions, which may have chemotaxonomic relevance, were F1I, an alpha-(1-3) glucan (alkalisoluble, water-insoluble), which amounted to 16.2-32.5% of the cell-wall material, and F1S (alkali and water-soluble) which represented 2.5-6.2% of the cell-wall material and was identified as a beta-(1-5) galactan. 13C-NMR spectra of the F1S fractions showed the same pattern for all the fungal species, characteristic of beta-(1-5) linked galactofuranose.

Aspergillus↗
PubMed1990

Synthesis and conformational studies of carrabiose and its 4'-sulphate and 2,4'-disulphate.

Methyl alpha-carrabioside (13), and its 4-sulphate (19) and 2,4-disulphate (20) have been synthesised via glycosylation of methyl 3,6-anhydro-2-O-benzyl-alpha-D-galactopyranoside with 2,3,6-tri-O-acetyl-4-O-benzyl-beta-D-galactopyranosyl bromide and subsequent partial or complete debenzylation, sulphation, and deprotection of the resulting disaccharide derivatives. Conformational studies have been carried out on 13, 19, and 20 on the basis of 1D and 2D 1H-n.m.r. spectroscopy and molecular mechanics calculations.

Carbohydrate Conformation↗
PubMedDate not supplied

Two new eudesmane alcohols from Jasonia glutinosa.

Two new sesquiterpene alcohols have been isolated from the aerial parts of Jasonia glutinosa D. C. The structure of these sesquiterpenes were characterized by 1D and 2D NMR techniques (DQCOSY. TOCSY, NOESY, HMQC and HMBC) as (11R)-eudesm-4-en-11,12-diol and (11R)-eudesmane-5alpha, 11,12-triol.

Alcohols↗