群体生物被膜中金黄色葡萄球菌程序性细胞死亡系统的调控机理研究
Abstract：
加油中国足球 Staphylococcus aureus (S. aureus) is a common pathogen that caus various infections in humans and animals. The ability to form biofilms allows S. aureus to resist host immune respons and antibiotic treatments, leading to chronic and persistent infections. Programmed cell death (PCD) has been reported to regulate biofilm formation and maintenance, and the regulation mechanisms are still not fully understood. In this review, we summarize recent advances in the understanding of the regulatory mechanisms of PCD in S. aureus biofilms, with a focus on stress respons, quorum nsing, and metabolic pathways.
Keywords: Staphylococcus aureus, biofilm, programmed cell death, stress respon, quorum nsing, metabolic pathways
Introduction:
Staphylococcus aureus (S. aureus) is a Gram-positive bacterium that is responsible for a wide range of infections in humans and animals, ranging from skin infections to vere systemic dias. The ability to form biofilms allows S. aureus to attach to various surfaces, resist immune respons, and tolerate antibiotic treatments, leading to chronic and persistent infections that are difficult to eradicate (Otto, 2018).
Biofilm formation is a complex process that involves the cretion of extracellular polymeric substances (EPS), including polysaccharides, proteins, and DNA, that form a three-dimensional matrix around the bacterial cells. This matrix protects the bacteria from environmental stress, such as desiccation, pH changes, and antibiotic treatments, making them highly resistant to eradication (Flemming and Wingender, 2010).
Programmed cell death (PCD) is a physiological process that is characterized by a ries of molecular events leading to the controlled and orderly lf-destruction of a cell. PCD has been reported to play a critical role in regulating biofilm formation and maintenance in various bacterial species, including S. aureus (Davies et al., 2016).
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Regulatory mechanisms of PCD in S. aureus biofilms:
Stress respon:
Stress respon pathways are known to play a critical role in regulating PCD in S. aureus biofilms. The SigB-dependent stress respon pathway has been reported to be involved in PCD regulation in S. aureus biofilms (Goerke et al., 2005). SigB is a transcriptional regulator that is activated under stress conditions, such as heat shock, pH changes, and oxidative stress. SigB activates the expression of various genes involved in cell envelope maintenance, amino acid biosynthesis, and energy metabolism, which are required for cell survival under stress conditions.幼儿园区角有哪些
Recent studies have shown that activation of the SigB pathway induces PCD in S. aureus biofilms by upregulating the expression of lrgAB, a two-component system that regulates PCD in S. aureus (Kearns et al., 2020). The LrgAB system consists of a membrane-bound protein LrgA and a cytoplasmic protein LrgB. LrgA inhibits autolysin activity, while LrgB inhibits the anti-autolysin activity of Atl. Under normal conditions, LrgA
B inhibits PCD by inhibiting autolysis. Under stress conditions, SigB induces lrgAB expression, leading to incread lrgA and decread lrgB expression, which results in incread autolysis and PCD.
Quorum Sensing:
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Quorum nsing is a cell-to-cell communication system that allows bacteria to coordinate gene expression in respon to changes in population density. Quorum nsing has been reported to regulate PCD in S. aureus biofilms by modulating the expression of virulence factors, EPS production, and biofilm dispersal (Li et al., 2018).
over的反义词 The agr quorum nsing system is known to be involved in the regulation of PCD in S. aureus biofilms (Bojer et al., 2017). The agr system compris two divergent transcriptional units, agrBDCA and RNAIII. AgrD is a precursor of the autoinducing peptide (AIP), which is synthesized and creted by the bacteria. AgrB is a protea that cleaves the propeptide of AgrD to generate the active AIP. AIP binds to the AgrC receptor, leading to phosphorylation of the AgrA transcriptional regulator and activation of the agr s
铃铛简笔画老鼠嫁女儿ystem. RNAIII is a small RNA that regulates the expression of target genes, including toxins, proteas, and EPS biosynthesis genes.
Recent studies have shown that the agr system induces PCD in S. aureus biofilms by upregulating the expression of lrgAB and cidABC, two two-component systems that regulate PCD in S. aureus (Bojer et al., 2017). The cidABC system consists of a membrane-bound protein CidA and two cytoplasmic proteins CidB and CidC. CidA activates autolysis and PCD, while CidB and CidC inhibit autolysis and PCD. The agr system induces cidABC expression, leading to incread cidA and decread cidB/cidC expression, which results in incread autolysis and PCD.
Metabolic pathways:
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Metabolic pathways have been reported to play a critical role in regulating PCD in S. aureus biofilms. Metabolites, such as fatty acids, amino acids, and carbohydrates, have been shown to induce PCD in S. aureus biofilms by activating stress respon pathways and modulating quorum nsing (Bojer et al., 2017).
