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Tn2009, a Tn916-Like Element Containing mef(E) in Streptococcus pneumoniae. Maria Del Grosso, 2004.The association between the macrolide efflux gene mef(E) and the tet(M) gene was studied in two clinical strains of Streptococcus pneumoniae that belonged to serotypes 19F and 6A, respectively, and that were resistant to both tetracycline and erythromycin . The mef(E)-carrying element mega (macrolide efflux genetic assembly; 5,511 bp) was found to be inserted into a Tn916-like genetic element present in the chromosomes of the two pneumococcal strains . In both strains, mega was integrated at the same site, an open reading frame identical to orf6 of Tn916 . The new composite element, Tn2009, was about 23.5 kb and, with the exception of the tet(M)-coding sequence, appeared to be identical in both strains . By sequencing of the junction fragments of Tn2009 at the site of insertion into the chromosome, it was possible to show that (i) the insertion site was identical in the two clinical strains and (ii) the integration of Tn2009 caused a 9.5 kb-deletion in the pneumococcal chromosome . It was not possible to detect the conjugal transfer of Tn2009 to a recipient pneumococcal strain; however, transfer of the whole element by transformation was shown to occur . It is possible to hypothesize that Tn2009 relies on transformation for its spread among clinical strains of S . pneumoniae . VanT, a Homologue of Vibrio harveyi LuxR, Regulates Serine, Metalloprotease, Pigment, and Biofilm Production in Vibrio anguillarum. Antony Croxatto, 2002.Vibrio anguillarum possesses at least two N-acylhomoserine lactone (AHL) quorum-sensing circuits, one of which is related to the luxMN system of Vibrio harveyi . In this study, we have cloned an additional gene of this circuit, vanT, encoding a V . harveyi LuxR-like transcriptional regulator . A V . anguillarum  vanT null mutation resulted in a significant decrease in total protease activity due to loss of expression of the metalloprotease EmpA, but no changes in either AHL production or virulence . Additional genes positively regulated by VanT were identified from a plasmid-based gene library fused to a promoterless lacZ . Three lacZ fusions (serA::lacZ, hpdA-hgdA::lacZ, and sat-vps73::lacZ) were identified which exhibited decreased expression in the
vanT strain . SerA is similar to 3-phosphoglycerate dehydrogenases and catalyzes the first step in the serine-glycine biosynthesis pathway . HgdA has identity with homogentisate dioxygenases, and HpdA is homologous to 4-hydroxyphenylpyruvate dioxygenases (HPPDs) involved in pigment production . V . anguillarum strains require an active VanT to produce high levels of an L-tyrosine-induced brown color via HPPD, suggesting that VanT controls pigment production . Vps73 and Sat are related to Vibrio cholerae proteins encoded within a DNA locus required for biofilm formation . A V . anguillarum
vanT mutant and a mutant carrying a polar mutation in the sat-vps73 DNA locus were shown to produce defective biofilms . Hence, a new member of the V . harveyi LuxR transcriptional activator family has been characterized in V . anguillarum that positively regulates serine, metalloprotease, pigment, and biofilm production .
Nontyphoidal Salmonellae in United Kingdom Badgers: Prevalence and Spatial Distribution. J. Sian Wilson, 2003.Eighteen (72%) of 25 badger social groups were found to excrete Salmonella enterica serovar Ried, S . enterica serovar Binza, S . enterica serovar Agama, or S . enterica serovar Lomita . Each serovar was susceptible to a panel of antimicrobials . Based on results of pulsed-field gel electrophoresis, the S . enterica serovar Agama and S . enterica serovar Binza isolates were very similar, but two clones each of S . enterica serovar Lomita and S . enterica serovar Ried were found . Badgers excreting S . enterica serovar Agama were spatially clustered .
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