The origin seems multi-factorial, but to an important extent explainable by prednisolone action. Gene signatures in patients with AAV undergoing steroid treatment should therefore be interpreted accordingly. “
“The endotoxic activities of lipopolysaccharides (LPS) isolated from different strains of rhizobia and rhizobacteria (Bradyrhizobium, Mesorhizobium, and Azospirillum) were compared to those of Salmonella enterica sv. Typhimurium LPS. The biological activity of all the examined preparations, measured as Limulus lysate gelation, production of tumor necrosis factor (TNF), interleukin-1β (IL-1β),
and interleukin-6 (IL-6), and nitrogen oxide (NO) induction in human myelomonocytic cells (line THP-1), was considerably lower than that of the reference enterobacterial endotoxin. Among the rhizobial lipopolysaccharides, the activities of Mesorhizobium Compound Library huakuii and Azospirillum lipoferum LPSs were higher than those of the LPS preparations from five strains of Bradyrhizobium. The weak endotoxic activity of the examined preparations was
correlated with differences in lipid A structure compared to Salmonella. Soil bacteria belonging to the rhizobium lineage are able to fix atmospheric nitrogen during symbiosis with legume plants. Bacteria from the genus Bradyrhizobium induce nitrogen-fixing nodules on the roots of cultivated (Glycine max and Glycine soya) and wild-growing legumes (1, 2). M. huakuii induces the formation of nodules on the roots of Astragalus sinicus (3). A. lipoferum represents plant-growth-promoting rhizobacteria which colonize the root surface and are not able to penetrate root through cells. They live in association PF-562271 clinical trial with roots of grasses, cereals, and other monocotyledonous plants (4, 5). Lipopolysaccharide, as an integral component of the cell walls of Gram-negative bacteria, plays an essential role in the proper development of symbiotic relationships (6). LPS, together with Omp proteins, is responsible for the asymmetric structure and semi-permeability of outer membranes. This is important for the appropriate morphogenesis and functionality of bacteroids, endosymbiotic forms of rhizobia which perform nitrogen
fixation (7). LPS may play a role in the protection of rhizobia against plant defense response mechanisms. Suppression of systemic acquired resistance or hypersensitivity reaction has been shown during infection of plant tissues by microsymbionts (8–10). Most pathogenic bacteria possess LPSs displaying endotoxic activity against host organisms. Lipid A, the part of LPSs that anchors the whole macromolecule in the outer membrane, is the centre of endotoxicity. The fine structure of enterobacterial lipid A has been identified as a glycolipid comprised of a β-(1,6)-linked glucosaminyl disaccharide substituted by two phosphate groups at positions C-1 and C-4 and six fatty acid residues with two acyloxyacyl moieties with a distinct location (Fig. 1) (11, 15, 16).