Abstract
Cells in biofilms dynamically adapt to surrounding environmental conditions, which alters biofilm architecture. The obligate anaerobic pathogen Clostridium perfringens shows different biofilm structures in different temperatures. Here we find that the temperature-regulated production of extracellular polymeric substance (EPS) is necessary for morphological changes in biofilms. We identify BsaA proteins as an EPS matrix necessary for pellicle biofilm formation at lower temperature and find that extracellularly secreted BsaA protein forms filamentous polymers. We show that sipW-bsaA operon expression is bimodal, and the EPS-producing population size is increased at a lower temperature. This heterogeneous expression of the EPS gene requires a two-component system. We find that EPS-producing cells cover EPS-nonproducing cells attaching to the bottom surface. In the deletion mutant of pilA2, encoding a type IV pilin, the EPS gene expression is ON in the whole population. This heterogeneity is further regulated by the cleavage of the pilA2 mRNA by RNase Y, causing temperature-responsive EPS expression in biofilms. As temperature is an environmental cue, C. perfringens may modulate EPS expression to induce morphological changes in biofilm structure as a strategy for adapting to interhost and external environments.
Highlights
Pathogenic bacteria adapt to both the host-internal and external environments for infection and survival
We showed that temperature drastically influences C. perfringens biofilm morphology, which indicates that C. perfringens modulates gene expression involved in biofilm formation in response to external environmental temperature[7]
We predicted a transcriptional terminator in the 3′ flanking region of bsaA and identified a transcriptional start site upstream of sipW (Supplementary Fig. 1a–c). Both sipW-bsaA bicistronic mRNA and sipW-bsaABCRSD polycistronic mRNA were transcribed from the RESULTS Identification of genes responsible for pellicle biofilm formation Previously, we reported that morphological changes in biofilm structure depend on the growth temperature of C. perfringens[7]
Summary
Pathogenic bacteria adapt to both the host-internal and external environments for infection and survival. They must be able to recognize these different environments, which leads to a differential response to be tolerant to various stresses in each environment. Oxygen and desiccation are environmental stresses that must be avoided in the external environment for strictly anaerobic pathogens to be able to be transmitted to different hosts. Determining how anaerobic pathogens respond to environmental signals outside the host and which biological processes are involved in adaptation to the environment are crucial for understanding the pathogenesis of anaerobic bacteria. Biofilm formation is thought to be a crucial ability for anaerobic pathogens to survive various internal/external environments. To understand biofilm properties and to develop antibacterial strategies, identification of the specific composition of EPS in biofilms associated with the biofilm architecture is crucial
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
