A dispensable SepIVA orthologue in Streptomyces venezuelae is associated with polar growth and not cell division.

Background: SepIVA has been reported to be an essential septation factor in Mycolicibacterium smegmatis and Mycobacterium tuberculosis. It is a coiled-coil protein with similarity to DivIVA, a protein necessary for polar growth in members of the phylum Actinomycetota. Orthologues of SepIVA are broadly distributed among actinomycetes, including in Streptomyces spp.

D-amino acids signal a stress-dependent run-away response in Vibrio cholerae.

To explore favourable niches while avoiding threats, many bacteria use a chemotaxis navigation system. Despite decades of studies on chemotaxis, most signals and sensory proteins are still unknown. Many bacterial species release D-amino acids to the environment; however, their function remains largely unrecognized.

Quantitative analysis of morphogenesis and growth dynamics in an obligate intracellular bacterium.

Obligate intracellular bacteria of the order Rickettsiales include important human pathogens. However, our understanding of the biology of species is limited by challenges imposed by their obligate intracellular lifestyle. To overcome this roadblock, we developed methods to assess cell wall composition, growth, and morphology of , a human pathogen in the spotted fever group of the genus.

Wzm/Wzt System: Changes in the Bacterial Envelope Lead to Improved Rev1Δ Vaccine Properties.

The lipopolysaccharide (LPS) O-polysaccharide (O-PS) is the main virulence factor in . After synthesis in the cytoplasmic membrane, O-PS is exported to the periplasm by the Wzm/Wzt system, where it is assembled into a LPS. This translocation also engages a bactoprenol carrier required for further biosynthesis pathways, such as cell wall biogenesis.

BipA exerts temperature-dependent translational control of biofilm-associated colony morphology in .

Adaptation to shifting temperatures is crucial for the survival of the bacterial pathogen . Here, we show that colony rugosity, a biofilm-associated phenotype, is regulated by temperature in strains that naturally lack the master biofilm transcriptional regulator HapR. Using transposon-insertion mutagenesis, we found the ortholog of BipA, a conserved ribosome-associated GTPase, is critical for this temperature-dependent phenomenon.

The Interaction of RecA With Both CheA and CheW Is Required for Chemotaxis.

is the most frequently reported cause of foodborne illness. As in other microorganisms, chemotaxis affords key physiological benefits, including enhanced access to growth substrates, but also plays an important role in infection and disease. Chemoreceptor signaling core complexes, consisting of CheA, CheW and methyl-accepting chemotaxis proteins (MCPs), modulate the switching of bacterial flagella rotation that drives cell motility.

Peptidoglycan Muropeptides: Release, Perception, and Functions as Signaling Molecules.

Peptidoglycan (PG) is an essential molecule for the survival of bacteria, and thus, its biosynthesis and remodeling have always been in the spotlight when it comes to the development of antibiotics. The peptidoglycan polymer provides a protective function in bacteria, but at the same time is continuously subjected to editing activities that in some cases lead to the release of peptidoglycan fragments (i.e.

Expansion of the SOS regulon of Vibrio cholerae through extensive transcriptome analysis and experimental validation.

Background: The SOS response is an almost ubiquitous response of cells to genotoxic stresses. The full complement of genes in the SOS regulon for Vibrio species has only been addressed through bioinformatic analyses predicting LexA binding box consensus and in vitro validation. Here, we perform whole transcriptome sequencing from Vibrio cholerae treated with mitomycin C as an SOS inducer to characterize the SOS regulon and other pathways affected by this treatment.

The Transient Multidrug Resistance Phenotype of Swarming Cells Is Abolished by Sub-inhibitory Concentrations of Antimicrobial Compounds.

Swarming motility is the rapid and coordinated multicellular migration of bacteria across a moist surface. During swarming, bacterial cells exhibit increased resistance to multiple antibiotics, a phenomenon described as adaptive or transient resistance. In this study, we demonstrate that sub-inhibitory concentrations of cefotaxime, ciprofloxacin, trimethoprim, or chloramphenicol, but not that of amikacin, colistin, kanamycin or tetracycline, impair swarming.

Molecular Interaction and Cellular Location of RecA and CheW Proteins in during SOS Response and Their Implication in Swarming.

In addition to its role in DNA damage repair and recombination, the RecA protein, through its interaction with CheW, is involved in swarming motility, a form of flagella-dependent movement across surfaces. In order to better understand how SOS response modulates swarming, in this work the location of RecA and CheW proteins within the swarming cells has been studied by using super-resolution microscopy. Further, and after docking studies, the specific RecA and CheW regions associated with the RecA-CheW interaction have also been confirmed by site-directed mutagenesis and immunoprecipitation techniques.

SOS System Induction Inhibits the Assembly of Chemoreceptor Signaling Clusters in Salmonella enterica.

Swarming, a flagellar-driven multicellular form of motility, is associated with bacterial virulence and increased antibiotic resistance. In this work we demonstrate that activation of the SOS response reversibly inhibits swarming motility by preventing the assembly of chemoreceptor-signaling polar arrays. We also show that an increase in the concentration of the RecA protein, generated by SOS system activation, rather than another function of this genetic network impairs chemoreceptor polar cluster formation.

RecA protein plays a role in the chemotactic response and chemoreceptor clustering of Salmonella enterica.

The RecA protein is the main bacterial recombinase and the activator of the SOS system. In Escherichia coli and Salmonella enterica sv. Typhimurium, RecA is also essential for swarming, a flagellar-driven surface translocation mechanism widespread among bacteria.