Applied and Environmental Microbiology, 72, 937– 941. ( 2006) Autoinducer 2 affects biofilm formation by Bacillus cereus. Auger, S., Krin, E., Aymerich, S., and Gohar, M.Applied and Environmental Microbiology, 70, 6887– 6891. ( 2004) New vector for efficient allelic replacement in naturally nontransformable, low-GC-content, gram-positive bacteria.
Christina candela full#
( 1994) Structural and functional analysis of the promoter region involved in full expression of the cryIIIA toxin gene of Bacillus thuringiensis. CalY is, therefore, a bifunctional protein, which switches from a cell-surface adhesin activity in early stationary phase, to the production of fibers in mid-stationary phase and in biofilms. Using purified CalY, we found that the protein polymerization occurred only in the presence of cell-surface components. The transcription study and the deletion of sipW suggested that CalY change of location is due to a delayed activity of the SipW signal peptidase. In mid-stationary phase and in biofilms, the location of CalY shifted from the cell surface to the extracellular medium, where it was found as fibers. Deletion of calY revealed that this protein plays a major role in adhesion to HeLa epithelial cells, to the insect Galleria mellonella hemocytes and in the bacterial virulence against larvae of this insect, suggesting that CalY is a cell-surface adhesin. In the early stationary phase of planktonic cultures, CalY was located at the bacterial cell-surface, as shown by immunodetection. We show here, in the closely related entomopathogenic species Bacillus thuringiensis, that CalY also displays a second function. The extracellular biofilm matrix often contains a network of amyloid fibers which, in the human opportunistic pathogen Bacillus cereus, includes the two homologous proteins TasA and CalY.
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