Correlations between carbon metabolism and virulence in bacteria.

Bacteria have developed several mechanisms which allow the preferred utilization of the most efficiently metabolizable carbohydrates when these organisms are exposed to a mixture of carbon sources. Interestingly, the same or similar mechanisms are used by some pathogens to control various steps of their infection process. The efficient metabolism of a carbon source might serve as signal for proper fitness.

Transcription regulators potentially controlled by HPr kinase/phosphorylase in Gram-negative bacteria.

Phosphorylation and dephosphorylation at Ser-46 in HPr, a phosphocarrier protein of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) is controlled by the bifunctional HPr kinase/phosphorylase (HprK/P). In Gram-positive bacteria, P-Ser-HPr controls (1) sugar uptake via the PTS; (2) catabolite control protein A (CcpA)-mediated carbon catabolite repression, and (3) inducer exclusion. Genome sequencing revealed that HprK/P is absent from Gram-negative enteric bacteria, but present in many other proteobacteria.

Differential expression of genes that harbor a common regulatory element in Neisseria meningitidis upon contact with target cells.

The expression of several genes in Neisseria meningitidis upon contact with epithelial cells was associated with the presence of the contact regulatory elements of NEISSERIA: These genes are involved in various aspects of meningococcal biology and could be coordinately regulated upon contact with target cells.

The duality of virulence and transmissibility in Neisseria meningitidis.

Neisseria meningitidis is a commensal bacterium of the human nasopharynx that occasionally provokes invasive disease. Carriage strains of N. meningitidis are heterogeneous, more frequent in nature and are transmitted among carriers.

Down-regulation of pili and capsule of Neisseria meningitidis upon contact with epithelial cells is mediated by CrgA regulatory protein.

The initial attachment of Neisseria meningitidis to the target cell surface appears to be largely pilus depend-ent in capsulated bacteria. Intimate adhesion subsequently occurs to permit colonization. We recently reported that insertional inactivation of the crgA gene, which encodes a transcriptional regulator belonging to the LysR family, decreased meningococcal adhesion to epithelial cells and abolished intimate adhesion.

Control of Neisseria gonorrhoeae pilin gene expression by environmental factors: involvement of the pilA/pilB regulatory genes.

The control of the expression of the pilin gene (pilE) in Neisseria gonorrhoeae under a wide variety of growth conditions has been studied. The expression of pilE was measured using transcriptional fusions between pilE and the gene encoding chloramphenicol acetyltransferase (CAT), and the level of pilin production was measured by Western blot analysis. Many of the conditions tested affected both growth rate and pilin gene expression (e.