M Perego

..The results invite speculation regarding the potential exploitation of this module as a molecular tool for applications in therapeutic design and biotechnology...

....

..anthracis, one of which, BA3790-3791, also affected sporulation initiation. The results suggest that the plasmid-borne Rap-Phr system may provide a selective advantage to the virulence of B. anthracis...

..An example of such a conversion is seen in Bacillus anthracis, and how acquired plasmid regulatory functions affect the activity of the regulatory processes of the bacterium, and vice versa, is now being revealed...

..Negative signals interpreted by aspartyl phosphate phosphatases appear to be a common mechanism in Gram-positive spore-forming microorganisms...

....

..Such phosphatases are prevalent in signal transduction systems controlling complex processes, such as the initiation of development in microorganisms...

..The identification of tetratricopeptide repeats in the Rap proteins may explain the mechanism by which Phr peptides bind to and inhibit the activity of Rap phosphatases...

....

..Since peptide transport is essential for inactivation of the negative regulation of sporulation by Rap phosphatases, the control of ScoC transcription repression activity plays a crucial role in the initiation of sporulation...

..The level of this regulator is, in turn, controlled by the spo0A gene. The pleiotropic phenotypes of spo0A mutants result from uncontrolled overexpression of the abrB regulator...

..The results suggest that multiple kinases exist for the Spo0A protein...

..The N-terminal region appears to be essential both for signal sensing and for maintaining the correct conformation of the autokinase component domains...

..Chromosome sequencing has revealed several other phosphatase-prepeptide gene pairs in B. subtilis, suggesting that the use of this mechanism may be widespread in signal transduction...

..Studies of the regulation of this gene have allowed the generation of a hypothesis to explain the interactions of those five stage 0 genes involved in the activation of sporulation-specific transcription...

..The results suggested that stationary phase functions and sporulation are repressed during active growth by AbrB and other transition state regulators by binding to the affected promoters in a concentration-dependent manner...

..anthracis sporulation in the bloodstream of its infected host, a salient characteristic in the virulence of this organism, and provides an additional role for the virulence plasmids in anthrax pathogenesis...

..The results are consistent with the view that the spoOA gene may control sporulation and transcription by modulating the level and activity of several regulatory proteins...

..Therefore, coordination of the terminal carboxylate group appears to be critical for peptide binding to RapA...

..We postulate that the accumulation of such peptides may play a signalling role in the initiation of sporulation, and that the sporulation defect in opp mutants results from an inability to transport these peptides...

..The function of PepF in B. subtilis remains unknown. Limited experiments with a yjbG paralogue called yusX indicated that a frameshift is present, making the corresponding gene product inactive...

..Since the transcription of the RapC- and RapF-encoding genes is positively regulated by their own target ComA, an autoregulatory circuit must exist for the competence transcription factor in order to modulate its activity...

..Our results link virulence factor production in B. anthracis to carbohydrate metabolism and, for the first time, provide a mechanistic explanation for AtxA transcriptional activity...

..These findings are significant not only to virulence regulation in B. anthracis, but also to analysis of virulence regulation in many pathogenic bacteria and to the study of cytochrome c activity in Gram-positive bacteria...

..The dual promoter activity and the extended untranslated mRNA suggest that as-yet-unknown regulatory mechanisms may act on this region to influence the level of AtxA in the cell...

..J. Biol. Chem. 281:37993-38003, 2006). We propose that these proteins may contribute to maintain B. anthracis in the transition phase of growth during an active infection and therefore contribute to the virulence of this organism...

..The results indicate that the loss of ResDE-controlled respiratory capacity does not affect the synthesis of anthrax toxin...

..S., and Dijkstra, B. W. (1999) Biochem. J. 339, 223-226 )...

..The utility of both systems was directly demonstrated through the mutagenesis of a widely used B. anthracis strain...

....

....

....

..subtilis (SipS, SipT, SipU, SipV, and SipW) are indispensable for Phr processing. However, we show that SipV and SipT have a previously undescribed role in sporulation, competence, and cell growth...

....

..The RapC mechanism of regulating ComA activity is a new example of how TPR motifs and their structural organization have been adapted for different specific functions within the B. subtilis Rap family...

..The residues involved in Spo0E interaction are identical in all Spo0A orthologues from spore-forming Bacilli encoding Spo0E phosphatases...

....

..These results may have broad implications for the design of endolysins as therapeutic agents...

..The sporulation of B. anthracis ex vivo appears to result from any one or a combination of the sporulation sensor histidine kinases remaining...

....

..The data demonstrated that glucose is an important host environment-derived signaling molecule and that CcpA is a molecular link between environmental sensing and B. anthracis pathogenesis...

..In this study, we demonstrated that FsrA also binds to two imperfect direct repeats separated by 13 bp, based on the consensus sequence of FsrA, T/AT/CAA/GGGAA/G, which is consistent with the binding characteristics of LytTR domains...

..The structural organization of Rap phosphatases in tetratricopeptide repeats provides insights on the mechanisms of RapA interaction with its substrate and its inhibitor...

..These results assign a role to the RR-HK17 TCS as coordinator of the enterococcal response to specific nutritional conditions existing at the site of bacterial invasion, the intestinal tract of an animal host...

..The possible functional roles of residues Asp-79 and Glu-81 were discussed...

..The implications of the structures for interactions between the phosphatases and their substrate Spo0A approximately P are discussed...

..Together, these results indicate that RapH is an integral part of a multifactorial regulatory circuit affecting the cell's decision between distinct developmental pathways...

..Overexpression of yyaA caused a sporulation defect characterized by the formation of multiple septa within the cell. This phenotype indicates that YyaA may have a regulatory role at the onset of sporulation...

..Our study suggests that YfkJ and YwlE play roles in B. subtilis stress resistance...

....

..The role of the Rap phosphatases not involved in sporulation will be investigated by microbiological and genetic approaches ..

..The role of the Rap phosphatases not involved in sporulation will be investigated by microbiological and genetic approaches ..

..The mechanisms of interaction of RapA with SpoOF will be studied by the surface plasmon resonance method and with a genetic approach. Genetic and biochemical approaches will be used for the identification of the target of RapC. ..