However, the other genes involved in EPS production in C. Type IV pili are extracellular appendages involved in attachment to host cells and are described as a component of the biofilm necessary for maximal biofilm formation 5, 9, 10. perfringens biofilms is reported to consist of extracellular DNA, extracellular proteins, and polysaccharides 5, 6, 7, 8. perfringens and are thus related to its pathogenesis. Therefore, in the natural environment, both sporulation and biofilm formation are survival strategies for C. Sporulation provides extreme resistance to environmental stresses, but spores are highly dormant and cannot quickly respond to environmental changes. perfringens was found to form biofilms, which provide increased tolerance to antibiotics and oxidative stresses 4, 5. This bacterium is an obligate anaerobe but is found widely in environments such as soil and the intestines of animals due to its spore-forming ability. Thus, 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.Ĭlostridium perfringens is a gram-positive spore-forming bacterium that is a causative agent of food poisoning, gas gangrene, and antibiotic-associated diarrhea because it produces numerous toxins and extracellular enzymes 3. Thus, biofilm formation is thought to be a crucial ability for anaerobic pathogens to survive various internal/external environments. The higher-order structure of biofilms is supported by EPS, which simultaneously confers tolerance to desiccation, oxidative stresses, and external antimicrobials 2. Cells in biofilms are surrounded by a self-produced matrix, known as extracellular polymeric substances (EPS), which are mainly composed of extracellular nucleic acids, proteins, and polysaccharides, although the specific composition varies across species 1. Most bacteria natively form biofilms, which are microbial multicellular communities. To overcome environmental stresses, one survival strategy is biofilm formation. 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. 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. Strictly anaerobic pathogens, as well as facultative anaerobes, are widespread throughout the environment, with a habitat inside the host in areas such as the gastrointestinal tract. They must be able to recognize these different environments, which leads to a differential response to be tolerant to various stresses in each environment. Pathogenic bacteria adapt to both the host-internal and external environments for infection and survival. perfringens may modulate EPS expression to induce morphological changes in biofilm structure as a strategy for adapting to interhost and external environments. As temperature is an environmental cue, C. This heterogeneity is further regulated by the cleavage of the pilA2 mRNA by RNase Y, causing temperature-responsive EPS expression in biofilms. In the deletion mutant of pilA2, encoding a type IV pilin, the EPS gene expression is ON in the whole population. We find that EPS-producing cells cover EPS-nonproducing cells attaching to the bottom surface. This heterogeneous expression of the EPS gene requires a two-component system. We show that sipW-bsaA operon expression is bimodal, and the EPS-producing population size is increased at a lower temperature. 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. Here we find that the temperature-regulated production of extracellular polymeric substance (EPS) is necessary for morphological changes in biofilms. The obligate anaerobic pathogen Clostridium perfringens shows different biofilm structures in different temperatures. Cells in biofilms dynamically adapt to surrounding environmental conditions, which alters biofilm architecture.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |