Agrobacterium tumefaciens Deploys a Versatile Antibacterial Strategy To Increase Its Competitiveness.

The type VI secretion system (T6SS) is a widespread antibacterial weapon capable of secreting multiple effectors for inhibition of competitor cells. Most of the effectors in the system share the same purpose of target intoxication, but the rationale for maintaining various types of effectors in a species is not well studied. In this study, we showed that a peptidoglycan amidase effector in , Tae, cleaves d-Ala--diaminopimelic acid (mDAP) and d-Glu bonds in peptidoglycan and is able to suppress the growth of recipient cells.

Is Required for Intracellular Replication of in Various Human Cells and Affects Its Polyamine Metabolism and Global Transcriptomes.

The gene has been reported to regulate polyamine metabolism in and , but its role in remains unknown. Our preliminary studies have revealed that widely affects the transcriptomes of infected M and Caco-2 cells and that it is required for the intracellular replication of serovar Typhimurium (. Typhimurium) in HeLa cells.

Impacts of Salmonella enterica Serovar Typhimurium and Its speG Gene on the Transcriptomes of In Vitro M Cells and Caco-2 Cells.

Microfold or membranous (M) cells are specialized intestinal epithelial cells responsible for host immunity. The speG mutant of Salmonella Typhimurium (S. Typhimurium) is a nonreplicating strain within human cells to be a candidate vaccine vector for interacting with M cells.

YjcC, a c-di-GMP phosphodiesterase protein, regulates the oxidative stress response and virulence of Klebsiella pneumoniae CG43.

This study shows that the expression of yjcC, an in vivo expression (IVE) gene, and the stress response regulatory genes soxR, soxS, and rpoS are paraquat inducible in Klebsiella pneumoniae CG43. The deletion of rpoS or soxRS decreased yjcC expression, implying an RpoS- or SoxRS-dependent control. After paraquat or H2O2 treatment, the deletion of yjcC reduced bacterial survival.

FimK regulation on the expression of type 1 fimbriae in Klebsiella pneumoniae CG43S3.

Klebsiella pneumoniae CG43, a heavy encapsulated liver abscess isolate, mainly expresses type 3 fimbriae. Type 1 fimbriae expression was only apparent in CG43S3ΔmrkA (the type 3 fimbriae-deficient strain). The expression of type 1 fimbriae in CG43S3ΔmrkA was reduced by deleting the fimK gene, but was unaffected by removing the 3' end of fimK encoding the C-terminal EIL domain (EILfimK).

Fur-dependent MrkHI regulation of type 3 fimbriae in Klebsiella pneumoniae CG43.

Type 3 fimbriae play a crucial role in Klebsiella pneumoniae biofilm formation, but the mechanism of the regulation of the type 3 fimbrial operon is largely unknown. In K. pneumoniae CG43, three regulatory genes, mrkH, mrkI and mrkJ, are located downstream of the type 3 fimbrial genes mrkABCDF.