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ABSTRACTThe diversity of monosaccharides and glycosidic linkages of extracellular polysaccharide (EPS) of high molecular weight were studied in strains morphologically assigned to the genus Ankistrodesmus. EPSs of seven strains were similar in both monosaccharides and glycosidic linkages, but showed exclusive characteristics or enough differences in proportions to distinguish strains. Fucose, glucose, rhamnose, mannose and galactose occurred in relatively high percentages in all strains. The strain CCMA-UFSCar 423, excluded from the genus Ankistrodesmusby the molecular marker tufA, was the only one containing galacturonic acid. Arabinose was found only in one A. densusstrain (CCMA-UFSCar 239). The species A. densusand A. stipitatus, which are known to have, respectively, stable mucilaginous capsules and pads in aqueous media, presented high percentages of the hydrophobic fucose and rhamnose on their polysaccharides. However, the strain CCMA-UFSCar 83, the only non-colonial A. densus, had low proportions of rhamnose. We also found variations in glycosidic linkages, and some of them were specific to one strain (e.g. 1-3 glucose in A. stipitatus). Conversely, the absence of common linkages was noteworthy for the strain outside the Ankistrodesmusclade, the CCMA-UFSCar 423. The data revealed important diversity in monosaccharides and linkages of the EPS within a single microalgae genus, and an important intraspecific diversity using a single growing condition. These differences could be useful as potential chemotaxonomic tools to help discriminating the Ankistrodesmusgenus or species, but also for future studies on intraspecific diversity within the genus. Moreover, the results show the relevance of studying and conserving closely related strains to preserve biodiversity. The diverse composition of high molecular weight EPSs shows a great potential for prospecting EPSs of economic interest.

Extracts, subfractions, isolated anthocyanins and procyanidins, and two phenolic acids from aronia [Aronia melanocarpa] were investigated for their CYP3A4 inhibitory effects, usingmidazolam as the probe substrate and recombinant insect cell microsomes expressing CYP3A4 as the enzyme source. Procyanidin B5 was a considerably stronger CYP3A4 inhibitor in vitro than the isomeric procyanidin B2 and comparable to bergamottin, a known CYP3A4 inhibitor from grapefruit juice. The inhibitory activity of proanthocyanidin-containing fractions was correlated to the degree of polymerization. Among the anthocyanins, cyanidin 3-arabinoside showed stronger CYP3A4 inhibition than cyanidin 3-galactoside and cyanidin 3-glucoside. Thus, the ability to inhibit CYP3A4 in vitro seems to be influenced by the sugar unit linked to the anthocyanidin. [ABSTRACT FROM AUTHOR]

The glycosylated amyloid light chain protein EPS was isolated from amyloid fibrils from the liver of a patient with Waldenstrom's macroglobulinemia. A tryptic glycopeptide of EPS (200 nmol) was isolated and characterized by 1H-n. m. r. The glycopeptide was digested with N-glycanase and the released oligosaccharides analyzed by high performance anion exchange chromatography. The monosaccharide composition and the linkage of the different oligosaccharides were determined by methanolysis and methylation analysis. The NMR spectrum revealed a bisected biantennary oligosaccharide as the main structure. HPAEC-PAD demonstrated the presence of several other related glycans in the glycopeptide preparation.