Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12-8QQ, Scotland, United Kingdom.
Published: February 2005
AI Article Synopsis
Article Abstract
The ATP-dependent caseinolytic proteases (Clp) are fundamental for stress tolerance and virulence in many pathogenic bacteria. The role of ClpC in the autolysis and virulence of Streptococcus pneumoniae is controversial. In this study, we tested the role of ClpC in a number of S. pneumoniae strains and found that the contribution of ClpC to autolysis is strain dependent. ClpC is required for the release of autolysin A and pneumolysin in serotype 2 S. pneumoniae strain D39. In vivo, ClpC is required for the growth of the pneumococcus in the lungs and blood in a murine model of disease, but it does not affect the overall outcome of pneumococcal disease. We also report the requirement of ClpP for the growth at elevated temperature and virulence of serotype 4 strain TIGR4 and confirm its contribution to the thermotolerance, oxidative stress resistance, and virulence of D39.
Purpose: Biofilms significantly contribute to the persistence and antibiotic resistance of infections. However, the regulatory mechanisms governing biofilm formation of remain not fully elucidated. This study aimed to investigate the function of the lineage-specific two-component system, , in biofilm regulation and pathogenicity.
Department of Microbiology, College of Basic Medical Sciences, Key Laboratory of Microbial Engineering Under the Educational Committee in Chongqing, Army Medical University, Chongqing, China.
Membrane vesicles (MVs) are produced by species across all domains of life and have diverse physiological functions as well as promising applications. While the mechanisms for vesiculation in Gram-negative bacteria are well-established, the genetic determinants and regulatory factors responsible for MV biogenesis in Gram-positive bacteria remain largely unknown. Here, we demonstrate that a Q225P substitution in the alternative sigma factor B (SigB) triggers MV production in Staphylococcus aureus strain Newman by hindering the specific binding of SigB to the asp23 promoter, thereby repressing expression of alkaline shock protein 23 (Asp23).
Staphylococcus aureus is a notorious pathogen responsible for various severe diseases. Due to the emergence of drug-resistant strains, the prevention and treatment of S. aureus infections have become increasingly challenging.
infection (CDI) with high morbidity and high mortality is an urgent threat to public health, and pathogenesis studies are eagerly required for CDI therapy. The major surface layer protein, SlpA, was supposed to play a key role in pathogenesis; however, a lack of isogenic mutants has greatly hampered analysis of SlpA functions. In this study, the whole gene was successfully deleted for the first time via CRISPR-Cas9 system.
Bacterial communities exhibit complex self-organization that contributes to their survival. To better understand the molecules that contribute to transforming a small number of cells into a heterogeneous surface biofilm community, we studied acellular aggregates, structures seen by light microscopy in colony biofilms using light microscopy and chemical imaging. These structures differ from cellular aggregates, cohesive clusters of cells important for biofilm formation, in that they are visually distinct from cells using light microscopy and are reliant on metabolites for assembly.
