RT Conference Proceedings
T1 A short version of the amyloid-like protein TasA fibrillates and supports biofilm formation in Bacillus cereus
A1 Caro-Astorga, Joaquín
A1 Pérez-García, Alejandro
A1 De-Vicente-Moreno, Antonio
A1 Romero-Hinojosa, Diego Francisco
K1 Biopelículas
AB The formation of bacterial biofilms is a doable thanks to the assembly of an extracellular matrix that provides to the entirecommunity with i) an outstanding architectonic structure and ii) protection to the cells from external aggressions. InBacillus subtilis, a structural element dedicated to the formation of the extracellular matrix is the amyloid-like protein TasA.To form fibers, TasA needs the participation of the protein TapA. Indeed, a tapA mutant resembles phenotypically to atasA mutant, which is wrinkle-less pellicles or colonies with no distinguishable morphological features. tasA is widelyspread within the Bacillus genus, but tapA is absent in the heterogeneous group of Bacillus cereus which includesenvironmental and pathogenic members; some of them are responsible for important food intoxication outbreaks. Then,we asked whether TasA would still retain functionality in biofilm formation in B. cereus. Comparative genomic analysisshowed a region in B. cereus containing two orthologous of tasA, tasA and calY, and the orthologous of sipW, thatencodes a signal peptidase. Our mutagenic studies revealed that the entire region was relevant for biofilm formation, andelectron microscopy proved the major propensity of TasA than CalY to form fibers in the cell surfaces. These findings alsoindicated that in B. cereus as opposed to B. subtilis, an accessory TapA protein is not necessary for the fibrillation ofTasA. Indeed, the heterologous expression of this region of B. cereus restored the capacity of a B. subtilis tasA operonmutant or a single tasA mutant to form pellicles. These pellicles stained with the amyloid dye Congo Red and the cellswere decorated with fibers, both findings suggestive of an amyloid-like nature of the B. cereus TasA. Intriguingly, in a B.subtilis tapA mutant, only the entire region of B. cereus fully rescued pellicle formation, fibrillation or Congo Red staining,to a lesser extent did sipw-tasA, and no restoration was observed with sipW-calY. These observations led us to speculatethat TapA might cross seed the fibrillation of TasA or CalY in B. subtilis. In summary, TasA is relevant for biofilm formationin these two bacterial species, which appears to be governed by its polymerizing nature. The fact that we count with twobacterial species containing versions of TasA with subtle differences will be of great value in our studies of themechanistic of polymerization of these bacterial amyloid-like fibers and their contribution to the assembly of theextracellular matrix.
YR 2015
FD 2015-11-12
LK http://hdl.handle.net/10630/10679
UL http://hdl.handle.net/10630/10679
LA eng
NO Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 25 ene 2026