The sugar 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) is a characteristic component of bacterial lipopolysaccharide (LPS, endotoxin). It connects the carbohydrate part of LPS with C6 of glucosamine or 2,3-diaminoglucose of lipid A by acid-labile α-ketosidic linkage. The number of Kdo units present in LPS, the way they are connected, and the occurrence of other substituents (P, PEtn, PPEtn, Gal, or β-l-Ara4N) account for structural diversity of the inner core region of endotoxin. In a majority of cases, Kdo is crucial to the viability and growth of bacterial cells. In this paper, the biosynthesis of Kdo and the mechanism of its incorporation into the LPS structure, as well as the location of this unique component in the endotoxin core structures, have been described.
Desulfovibrio desulfuricansanaerobes are constituents of human alimentary tract microflora. There are suggestions that they take part in the pathogenesis of periodontitis and some gastrointestinal inflammatory disorders, such as ulcerative colitis or Crohn’s disease. Endotoxin is one of Gram-negative bacteria cellular components that influence these microorganisms pathogenicity. Endotoxin is a lipid-polisaccharide heteropolymer consisting of three elements: lipid A, core oligosaccharide, and O-specific polysaccharide, also called antigen-O. The biological activity of lipopolysaccharide (LPS) is determined by its structure. In this study, we show that rhamnose, fucose, mannose, glucose, galactose, heptose, and 2-keto-3-deoxyoctulosonic acid (Kdo) are constituents ofD. desulfuricansendotoxin oligosaccharide core and O-antigen. Lipid A of these bacteria LPS is composed of glucosamine disaccharide substituted by 3-acyloxyacyl residues: ester-bound 3-(dodecanoyloxy)tetradecanoic, 3-(hexadecanoyloxy)tetradecanoic acid, and amide-bound 3-(tetradecanoyloxy)tetradecanoic acid.
Quantification of p65, p50 and IκBα mRNAs was performed by real time QRT-PCR in Caco-2 cells treated with 10, 50, and 100 μg/mL of Desulfovibrio desulfuricans LPS for 1, 6, 12, and 24 h. A strong increase in expression of p65 and IλBα genes was induced by 10 and 100 μg/mL of LPS at 1 h; after 6 h higher transcript amounts of both genes were observed at 100 μg/mL LPS. The p65 expression level was significantly increased by 50 and 100 μg/mL at 12 h and lowered by all LPS doses at 24 h. No significant differences between IκBα mRNA quantity in cells exposed to LPS at 12 and 24 h were observed. No changes in expression of p50 mRNA were induced by LPS. The expression of p65 gene positively correlated with IκBα gene expression. D. desulfuricans LPS is capable of modulating transcriptional activity of p65 and IκBα genes in intestinal epithelial cells.
A possible use of synchronous culture of Chlorella vulgaris algae has been examined as a shortterm bioassay for water quality control. Experiments were performed with algae cultivated in liquid media prepared with distilled water (control) and with water aliquots sampled from the Goczałkowice Reservoir. It has been demonstrated that changes in the absorbance (at 680 nm) of algae liquid synchronous culture and the rate of algae cellular division may be useful as criteria for water quality control. Changes in the algae metabolic activity are clearly a sign of the July flood and autumnal water quality changes.
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