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FlhA influences Bacillus thuringiensis PlcR-regulated gene transcription, protein production, and virulence.
Appl Environ Microbiol 2005; 71(12):8903-10AE

Abstract

Bacillus thuringiensis and Bacillus cereus are closely related. B. thuringiensis is well known for its entomopathogenic properties, principally due to the synthesis of plasmid-encoded crystal toxins. B. cereus appears to be an emerging opportunistic human pathogen. B. thuringiensis and B. cereus produce many putative virulence factors which are positively controlled by the pleiotropic transcriptional regulator PlcR. The inactivation of plcR decreases but does not abolish virulence, indicating that additional factors like flagella may contribute to pathogenicity. Therefore, we further analyzed a mutant (B. thuringiensis 407 Cry(-) DeltaflhA) previously described as being defective in flagellar apparatus assembly and in motility as well as in the production of hemolysin BL and phospholipases. A large picture of secreted proteins was obtained by two-dimensional electrophoresis analysis, which revealed that flagellar proteins are not secreted and that production of several virulence-associated factors is reduced in the flhA mutant. Moreover, we quantified the effect of FlhA on plcA and hblC gene transcription. The results show that the flhA mutation results in a significant reduction of plcA and hblC transcription. These results indicate that the transcription of several PlcR-regulated virulence factors is coordinated with the flagellar apparatus. Consistently, the flhA mutant also shows a strong decrease in cytotoxicity towards HeLa cells and in virulence against Galleria mellonella larvae following oral and intrahemocoelic inoculation. The decrease in virulence may be due to both a lack of flagella and a lower production of secreted factors. Hence, FlhA appears to be an essential virulence factor with a pleiotropic role.

Authors+Show Affiliations

Unité Génétique Microbienne et Environnement, INRA, La Minière, 78285 Guyancourt Cedex, France.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16332888

Citation

Bouillaut, Laurent, et al. "FlhA Influences Bacillus Thuringiensis PlcR-regulated Gene Transcription, Protein Production, and Virulence." Applied and Environmental Microbiology, vol. 71, no. 12, 2005, pp. 8903-10.
Bouillaut L, Ramarao N, Buisson C, et al. FlhA influences Bacillus thuringiensis PlcR-regulated gene transcription, protein production, and virulence. Appl Environ Microbiol. 2005;71(12):8903-10.
Bouillaut, L., Ramarao, N., Buisson, C., Gilois, N., Gohar, M., Lereclus, D., & Nielsen-Leroux, C. (2005). FlhA influences Bacillus thuringiensis PlcR-regulated gene transcription, protein production, and virulence. Applied and Environmental Microbiology, 71(12), pp. 8903-10.
Bouillaut L, et al. FlhA Influences Bacillus Thuringiensis PlcR-regulated Gene Transcription, Protein Production, and Virulence. Appl Environ Microbiol. 2005;71(12):8903-10. PubMed PMID: 16332888.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - FlhA influences Bacillus thuringiensis PlcR-regulated gene transcription, protein production, and virulence. AU - Bouillaut,Laurent, AU - Ramarao,Nalini, AU - Buisson,Christophe, AU - Gilois,Nathalie, AU - Gohar,Michel, AU - Lereclus,Didier, AU - Nielsen-Leroux,Christina, PY - 2005/12/8/pubmed PY - 2006/2/8/medline PY - 2005/12/8/entrez SP - 8903 EP - 10 JF - Applied and environmental microbiology JO - Appl. Environ. Microbiol. VL - 71 IS - 12 N2 - Bacillus thuringiensis and Bacillus cereus are closely related. B. thuringiensis is well known for its entomopathogenic properties, principally due to the synthesis of plasmid-encoded crystal toxins. B. cereus appears to be an emerging opportunistic human pathogen. B. thuringiensis and B. cereus produce many putative virulence factors which are positively controlled by the pleiotropic transcriptional regulator PlcR. The inactivation of plcR decreases but does not abolish virulence, indicating that additional factors like flagella may contribute to pathogenicity. Therefore, we further analyzed a mutant (B. thuringiensis 407 Cry(-) DeltaflhA) previously described as being defective in flagellar apparatus assembly and in motility as well as in the production of hemolysin BL and phospholipases. A large picture of secreted proteins was obtained by two-dimensional electrophoresis analysis, which revealed that flagellar proteins are not secreted and that production of several virulence-associated factors is reduced in the flhA mutant. Moreover, we quantified the effect of FlhA on plcA and hblC gene transcription. The results show that the flhA mutation results in a significant reduction of plcA and hblC transcription. These results indicate that the transcription of several PlcR-regulated virulence factors is coordinated with the flagellar apparatus. Consistently, the flhA mutant also shows a strong decrease in cytotoxicity towards HeLa cells and in virulence against Galleria mellonella larvae following oral and intrahemocoelic inoculation. The decrease in virulence may be due to both a lack of flagella and a lower production of secreted factors. Hence, FlhA appears to be an essential virulence factor with a pleiotropic role. SN - 0099-2240 UR - https://www.unboundmedicine.com/medline/citation/16332888/FlhA_influences_Bacillus_thuringiensis_PlcR_regulated_gene_transcription_protein_production_and_virulence_ L2 - http://aem.asm.org/cgi/pmidlookup?view=long&pmid=16332888 DB - PRIME DP - Unbound Medicine ER -