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Adhesion to cellulose of the Gram-positive bacterium Ruminococcus albus involves type IV pili The EMBL accession number for the sequence reported in this paper is AJ416469

Authors :
Pascale Mosoni
Michel Hébraud
Harivony Rakotoarivonina
Brigitte Gaillard-Martinie
Evelyne Forano
Grégory Jubelin
Source :
Microbiology. 148:1871-1880
Publication Year :
2002
Publisher :
Microbiology Society, 2002.

Abstract

This study was aimed at characterizing a cell-surface 25 kDa glycoprotein (GP25) that was previously shown to be underproduced by a spontaneous adhesion-defective mutant D5 of Ruminococcus albus 20. An antiserum against wild-type strain 20 was adsorbed with the mutant D5 to enrich it in antibodies 'specific' to adhesion structures of R. albus 20. The resulting antiserum, called anti-Adh serum, blocked adhesion of R. albus 20 and reacted mainly with GP25 in bacterial and extracellular protein fractions of R. albus 20. The N-terminal sequence of purified GP25 was identical to that of CbpC, a 21 kDa cellulose-binding protein (CBP) of R. albus 8. The nucleotide sequence of the gp25 gene was determined by PCR and genomic walking procedures. The gp25 gene encoded a protein of 165 aa with a calculated molecular mass of 16940 Da that showed 72.9% identity with CbpC and presented homologies with type IV pilins of Gram-negative pathogenic bacteria. Negative-staining electron microscopy revealed fine and flexible pili surrounding R. albus 20 cells while mutant cells were not piliated. In addition, immunoelectron microscopy showed that the anti-Adh serum probing mainly GP25, completely decorated the pili surrounding R. albus 20, thereby showing that GP25 was a major pilus subunit. This study shows for the first time the presence of pili at the surface of R. albus and identifies GP25 as their major protein subunit. Though GP25 was not identified as a CBP, isolated pili were shown to bind cellulose. In conclusion, these pili, which belong to the family of type IV pili, mediate adhesion of R. albus 20 to cellulose.

Details

ISSN :
14652080 and 13500872
Volume :
148
Database :
OpenAIRE
Journal :
Microbiology
Accession number :
edsair.doi...........805fad8e7f08ec8f58a77bbdd0b0c899
Full Text :
https://doi.org/10.1099/00221287-148-6-1871