A Porphyromonas gingivalis mutant defective in a putative glycosyltransferase exhibits defective biosynthesis of the polysaccharide portions of lipopolysaccharide, decreased gingipain activities, strong autoaggregation, and increased biofilm formation.
The Gram-negative anaerobic bacterium Porphyromonas gingivalis is a major pathogen in periodontal disease, one of the biofilm-caused infectious diseases. The bacterium possesses potential virulence factors, including fimbriae, proteinases, hemagglutinin, lipopolysaccharide (LPS), and outer membrane vesicles, and some of these factors are associated with biofilm formation; however, the precise mechanism of biofilm formation is still unknown. Colonial pigmentation of the bacterium on blood agar plates is related to its virulence. In this study, we isolated a nonpigmented mutant that had an insertion mutation within the new gene PGN_1251 (gtfB) by screening a transposon insertion library. The gene shares homology with genes encoding glycosyltransferase 1 of several bacteria. The gtfB mutant was defective in biosynthesis of both LPSs containing O side chain polysaccharide (O-LPS) and anionic polysaccharide (A-LPS). The defect in the gene resulted in a complete loss of surface-associated gingipain proteinases, strong autoaggregation, and a marked increase in biofilm formation, suggesting that polysaccharide portions of LPSs influence attachment of gingipain proteinases to the cell surface, autoaggregation, and biofilm formation of P. gingivalis.
Yamaguchi
Mikiyo
M
Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Osaka 565-0871, Japan.
Sato
Keiko
K
Yukitake
Hideharu
H
Noiri
Yuichiro
Y
Ebisu
Shigeyuki
S
Nakayama
Koji
K
D018829:Adhesins, Bacterial / Q000032:analysis* / Q000502:physiology; D018441:Biofilms; D003546:Cysteine Endopeptidases / Q000032:analysis* / Q000502:physiology; D004251:DNA Transposable Elements; D000080867:Gingipain Cysteine Endopeptidases; D016695:Glycosyltransferases / Q000502:physiology*; D008070:Lipopolysaccharides / Q000032:analysis / Q000096:biosynthesis* / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D009154:Mutation; D016966:Porphyromonas gingivalis / Q000502:physiology*
D018829:Adhesins, Bacterial; D004251:DNA Transposable Elements; D000080867:Gingipain Cysteine Endopeptidases; D008070:Lipopolysaccharides; D016695:Glycosyltransferases; D003546:Cysteine Endopeptidases