We have previously shown that outer membrane protein A (OmpA) and type 1 fimbriae are the bacterial determinants involved in Escherichia coli K1 binding to human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. In investigating the role of OmpA in E. coli K1 binding to HBMEC, we showed for the first time that ompA deletion decreased the expression of type 1 fimbriae in E. coli K1. Decreased expression of type 1 fimbriae in the ompA deletion mutant was largely the result of driving the fim promoter toward the type 1 fimbrial phase-OFF orientation. mRNA levels of fimB and fimE were found to be decreased with the OmpA mutant compared to the parent strain. Of interest, the ompA deletion further decreased the abilities of E. coli K1 to bind to and invade HBMEC under the conditions of fixing type 1 fimbria expression in the phase-ON or phase-OFF status. These findings suggest that the decreased ability of the OmpA mutant to interact with HBMEC is not entirely due to its decreased type 1 fimbrial expression and that OmpA and type 1 fimbriae facilitate the interaction of E. coli K1 with HBMEC at least in an additive manner.
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http://dx.doi.org/10.1128/IAI.00321-06 | DOI Listing |
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.
View Article and Find Full Text PDFPLoS Pathog
December 2024
Structural Studies Division, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, United Kingdom.
Type IV pili (T4Ps) are abundant in many bacterial and archaeal species, where they play important roles in both surface sensing and twitching motility, with implications for adhesion, biofilm formation and pathogenicity. While Type IV pilus (T4P) structures from other organisms have been previously solved, a high-resolution structure of the native, fully assembled T4P of Pseudomonas aeruginosa, a major human pathogen, would be valuable in a drug discovery context. Here, we report a 3.
View Article and Find Full Text PDFBrain Res Bull
December 2024
Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK; School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK. Electronic address:
Recent clinical trials targeting tau protein aggregation have heightened interest in tau-based therapies for dementia. Success of such treatments depends crucially on translation from non-clinical animal models. Here, we present the age profile of the PLB2 knock-in model of fronto-temporal dementia in terms of cognition, and by utilising a directly translatable magnetic resonance imaging approach.
View Article and Find Full Text PDFAntonie Van Leeuwenhoek
November 2024
State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Science, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, 361000, People's Republic of China.
A Gram-stain-negative bacterium, designated as strain TK19100, was isolated from the mid-ridge of the Southwest Indian Ocean. Cells of strain TK19100 were strictly aerobic, non-motile and short-rod shaped with fimbriae-like structures around the cell surface. Growth occurred at 15-40 °C, at pH 6.
View Article and Find Full Text PDFActa Crystallogr D Struct Biol
December 2024
Department of Chemistry, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada.
The type IV pilus is a diverse molecular machine capable of conferring a variety of functions and is produced by a wide range of bacterial species. The ability of the pilus to perform host-cell adherence makes it a viable target for the development of vaccines against infection by human pathogens such as Pseudomonas aeruginosa. Here, the 1.
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