Klebsiella pneumoniae type 3 fimbriae are encoded by mrkABCDF genes which produce the major pilin subunit MrkA, chaperone MrkB, outer membrane usher MrkC, adhesin MrkD and MrkF of unknown function, respectively. RT-PCR analysis demonstrated that the mrkF gene is contained within the mrk operon. Deletion of mrkF in K. pneumoniae CG43 was found to reduce biofilm formation. A higher level of biofilm formation activity was also observed in recombinant Escherichia coli JM109[pmrkABCDF] compared to that observed for JM109[pmrkABCD]. Immunoelectron microscopy analysis of recombinant type 3 fimbriae using anti-MrkA and anti-MrkF antibody-labeled gold particles revealed that MrkF intermittently inserted into the MrkA filament. An interaction between recombinant MrkA and MrkF was demonstrated by co-immunoprecipitation analysis, further supporting the notion that MrkF is a structural component of the fimbriae. Intriguingly, the incorporation of MrkF appeared to decrease fimbrial length but increased activity of autoaggregation and biofilm formation in the bacteria JM109[pmrkABCDF]. This suggested that MrkF may play a role in assembly of the filament.
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http://dx.doi.org/10.1016/j.resmic.2008.10.009 | 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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