, 1996). Clearly, lipopolysaccharide was still synthesized INCB018424 in the LaiMut strain (Fig. 1), but not in a normal manner. Our hypothesis is that expression

of the gene in the mutant results in two proteins. The disruption of the close relationship between the two distinct parts of the LA1647 protein, which is the result of the inframe stop, causes a disorderly assembly of lipopolysaccharide and the consequential loss of one or more of the normal surface epitopes present on the lipopolysaccharide. The expression of this gene as two proteins is plausible, given the presence of a potential start codon located eight bases downstream of the stop codon in the LaiMut sequence. Furthermore, the stop is located between the undecaprenyl-binding region (T-region, Fig. 4) and the galactosyltransferase region (GT-region, Fig. 4), and thus dividing the coding region at the inframe stop is unlikely to interfere with the function of the separately translated

domains. The analysis of the LaiMut strain highlights the complexity of the micromachinery used by Leptospira to produce lipopolysaccharide. There are two aspects to stressing Ku-0059436 the importance of research related to leptospiral lipopolysaccharide. Firstly, the importance of leptospiral lipopolysaccharide to the bacterium itself must be immense; approximately 2.5% of the Lai genome is committed to lipopolysaccharide biosynthesis. Clearly, lipopolysaccharide is a critical, primary interface between Leptospira and the host. Secondly, an understanding of how the epitope diversity attributable to the lipopolysaccharide found in the >230 leptospiral serovars is encoded by combinations of sugars in the lipopolysaccharides may lead to simplified strategies for the development Tangeritin of broadly protective vaccines for leptospirosis. “
“The fabXL genes encode enzymes that synthesize the very-long-chain fatty acid

– a unique acyl modification located at the 2′ position of the lipid A of Gram-negative bacteria in the order Rhizobiales. Mutation of the fabXL genes causes sensitivity to outer membrane stressors and other envelope-related stresses; however, the underlying mechanisms for increased sensitivity are poorly understood. We found that expression of the outer membrane protein gene ropB is down-regulated in an acpXL mutant. Furthermore, constitutive expression of ropB in an acpXL or fabF2XL, fabF1XL mutant restores tolerance to detergents, hyperosmotic stress, and acidic pH. The fabF2XL, fabF1XL mutant also has a delayed nodulation phenotype, whereas a ropB mutant has no observable defects in nodulation, demonstrating that mutation of the fabXL genes results in pleiotropic phenotypes that can be classified as either ropB dependent or ropB independent. Ex-nodule isolates of the mutant strains display restored tolerance to detergents and hyperosmotic and acidic stress conditions; however, the rescued phenotypes are not owing to increased ropB expression.