In this work we present evidence of an opposite regulation in the phytopathogenic bacteria Erwinia amylovora between the virulence-associated Type III secretion system (TTSS) and the flagellar system. Using loss-of-function mutants we show that motility enhanced the virulence of wild-type bacteria relative to a nonmotile mutant when sprayed on apple seedlings with unwounded leaves. Then we demonstrated through analyses of motility, flagellin export and visualization of flagellar filament that HrpL, the positive key regulator of the TTSS, also down-regulates the flagellar system. Such a dual regulation mediated by an alternative sigma factor of the TTSS appears to be a level of regulation between virulence and motility not yet described among Proteobacteria.
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http://dx.doi.org/10.1111/j.1574-6968.2006.00172.x | DOI Listing |
Environ Res
January 2025
National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing, 100124, China. Electronic address:
Dinotefuran (DIN) is toxic to non-target organisms and accelerates the evolution of antibiotic resistance, which poses a problem for the stable operation of the activated sludge process in wastewater treatment plants (WWTPs). However, the emergence and the transfer mechanism of antibiotic resistance genes (ARGs) in activated sludge systems under DIN stress remains unclear. Thus, in the study, the potential impact of DIN on ARGs and virulence factor genes (VFGs) in aerobic granular sludge (AGS) was investigated in depth using metagenomic binning and functional modules.
View Article and Find Full Text PDFMicrolife
January 2025
Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), D-97080 Würzburg, Germany.
Bacterial small proteins impact diverse physiological processes, however, technical challenges posed by small size hampered their systematic identification and biochemical characterization. In our quest to uncover small proteins relevant for pathogenicity, we previously identified YjiS, a 54 amino acid protein, which is strongly induced during this pathogen's intracellular infection stage. Here, we set out to further characterize the role of YjiS.
View Article and Find Full Text PDFCommun Biol
December 2024
Yunnan Provincial Key Laboratory of Animal Nutrition and Feed, Faculty of Animal Science and Technology, Yunnan Agricultural University, Kunming, China.
Flagella are essential for biofilm formation, adhesion, virulence, and motility. In this study, the deletion of argR resulted in defects in flagellar synthesis and reduced motility, nevertheless, the underlying mechanism by which ArgR regulated bacterial motility remained unclear. ChIP-Seq and RNA-Seq analysis revealed that ArgR regulated the expression of flagellar genes, concluding two-component system flrBC and multitudinous flagellar structure genes.
View Article and Find Full Text PDFmBio
December 2024
Division of Infectious Diseases, Brigham and Women's Hospital, Boston, Massachusetts, USA.
Unlabelled: Bacteria have evolved diverse strategies to ensure survival under nutrient-limited conditions, where rapid energy generation is not achievable. Here, we performed a transposon insertion site sequencing loss-of-function screen to identify genes that promote pathogen fitness in stationary phase. We discovered that the aintenance of ipid symmetry (Mla) pathway, which is crucial for transferring phospholipids from the outer to the inner membrane, is critical for stationary phase fitness.
View Article and Find Full Text PDFSci China Life Sci
December 2024
Soong Ching Ling Institute of Maternity and Child Health, International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200030, China.
Asthenoteratozoospermia is a common cause of male infertility. To further define the genetic causes underlying asthenoteratozoospermia, we performed whole-exome sequencing in a cohort of Han Chinese men with asthenoteratozoospermia. Homozygous deleterious variants of MYCBPAP were first identified in two unrelated Chinese cases.
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