Four novel mrkD alleles namely mrkD(V1), mrkD(V2), mrkD(V3), and mrkD(V4) were identified in seventeen Klebsiella pneumoniae meningitis strains using PCR-RFLP and sequence determination. Comparative analysis revealed a most variable region containing an RGD motif in the receptor domain of MrkD(V3). In order to determine if the sequence confers the K. pneumoniae mrkD(V3) the highest level of the fimbrial activity, a type 3 fimbriae display system was constructed in Escherichia coli. The E. coli JM109[pmrkABCD(V3)F] displaying meshwork-like fimbriae also had the most fimbrial activity, supporting a possible role of the varied sequences. In a dose-dependent manner, the GRGDSP hexapeptide appeared to inhibit the adhesion of the E. coli JM109[pmrkABCD(V3)F] to HCT-8, an ileocecal epithelial cell line. In addition, the adhesion activity was reduced by the addition of anti-alpha5beta1 integrin monoclonal antibody, indicating that the RGD containing region in MrkD(V3) is responsible for the binding of type 3 fimbriae to integrin.
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http://dx.doi.org/10.1016/j.bbrc.2006.09.070 | DOI Listing |
Appl Environ Microbiol
January 2025
Institute for Chemistry and Biology of the Marine Environment (ICBM), School of Mathematics and Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany.
Vitamin B (cobalamin, herein B) is a key cofactor for most organisms being involved in essential metabolic processes. In microbial communities, B is often scarce, largely because only few prokaryotes can synthesize B and are thus considered B-prototrophs. B-auxotrophy is mostly manifested by the absence of the B-independent methionine synthase, MetE.
View Article and Find Full Text PDFMicrob Biotechnol
January 2025
Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA.
The increasing threat of antibiotic resistance underscores the urgent need for innovative strategies to combat infectious diseases, including the development of antivirulants. Microbial pathogens rely on their virulence factors to initiate and sustain infections. Antivirulants are small molecules designed to target virulence factors, thereby attenuating the virulence of infectious microbes.
View Article and Find Full Text PDFNat Commun
January 2025
National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China.
Uropathogenic Escherichia coli (UPEC) is a major cause of urinary tract infections (UTIs). Invasion into bladder epithelial cells (BECs) on the bladder luminal surface via type 1 fimbria is the first critical step in UPEC infection. Although type 1 fimbria expression increases during UPEC invasion of BECs, the underlying regulatory mechanisms remain poorly understood.
View Article and Find Full Text PDFJ Vet Res
December 2024
Equipe de Recherche sur les Relations Matrice Extracellulaire-Cellule (ERRMECe) Laboratory, Site de St-Martin, CY Cergy Paris University, 95302 Cergy-Pontoise, France.
Introduction: is the most common uropathogen in humans, dogs and cats. Dietary consumption of cranberry () is known to be associated with a reduction in uropathogenic (UPEC) adhesion to human and canine urinary epithelial cell lines, but this has not been shown in cats.
Material And Methods: Six neutered domestic cats, one male and five females, were randomly fed three diets successively, one containing 0.
bioRxiv
December 2024
Department of Biochemistry, University of Washington, Seattle, WA.
A critical step in infections is the attachment of many microorganisms to host cells using lectins that bind surface glycans, making lectins promising antimicrobial targets. Upon binding mannosylated glycans, FimH, the most studied lectin adhesin of type 1 fimbriae in , undergoes an allosteric transition from an inactive to an active conformation that can act as a catch-bond. Monoclonal antibodies that alter FimH glycan binding in various ways are available, but the mechanisms of these antibodies remain unclear.
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