Caracterização dos padrões de expressão de glucosiltransferases B e C, da proteina ligante de glucano B e de possiveis genes reguladores em genotipos distintos de Streptococcus mutans / Expression analysis of glucosyltransferases B and C, glucan-binding protein B and their putative regulatory genes in distinct genotypes of Streptococcus mutans

AUTOR(ES)

Rafael Nobrega Stipp

DATA DE PUBLICAÇÃO

2006

RESUMO

Streptococcus mutans, the main pathogen of dental caries, have the capacity to accumulate in the dental biofilm in the presence of sucrose, under highly acidic conditions that are responsible for teeth demineralization. The glucosyltransferases B (GtfB) and C (GtfC) produced by S. mutans are essential in this process, because catalyze the synthesis of water-insoluble from sucrose. The Glucan-binding protein B (GbpB) appears to also participate in S. mutans accumulation, but under processes that are still unclear. Little is known about the mechanisms that regulate expression of genes encoding these proteins (gtfB, gtfC and gbpB). In this sense, we aimed to characterize the patterns of transcription of gtfB, gtfC and gbpB in distinct S. mutans genotypes. For that purpose, semi-quantitative analysis of reverse transcription?PCR (RT-PCR) were performed in strains at different phases of the growth curves in Brain Heart Infusion broth bath cultures at 37°C, under anaerobiosis. RNAs were extracted from cells at different growth phases, and applied in reactions of reverse transcription with arbitrary primers to yield total cDNAs. Semi-quantitative PCR reactions were then performed with the cDNAs using specific primers to each target gene, and normalized by the expression of the housekeeping gene 16SRNA, whose expression remained constant at the experimental conditions. Patterns of expression of gtfB and gtfC were specific to the strain background. Transcriptions of gtfB e de gtfC were coordinated in specific phases of growth, but the curves of transcription diverged at different phases in the majority of the genotypes studied. The levels of gbpB transcripts were variable between strains and assumed an independent pattern when compared with gtf genes. The levels of gbpB transcripts were characterized by lesser variations between the different phases of growth. The regulatory genes have shown peaks of expression at log and/or stationary phases of growth and the curves of transcript levels were strain-dependent. The results indicate that patterns of expression of gtfB, gtfC and gbpB and regulatory genes are strain-specific, and that gtfB and gtfC are regulated by distinct systems that may be activated at distinct phases of growth

ASSUNTO(S)

biofilme reação em cadeia da polimerase via transcriptase reversa biofilm reverse transcriptase polymerase chain reaction

Documentos Relacionados

• Immunogenicity and Protective Immunity Induced by Synthetic Peptides Associated with Putative Immunodominant Regions of Streptococcus mutans Glucan-Binding Protein B
• Purification and antigenicity of a novel glucan-binding protein of Streptococcus mutans.
• Multiple glucan-binding proteins of Streptococcus sobrinus.
• An 87-kilodalton glucan-binding protein of Streptococcus sobrinus B13.
• Sequence analysis of the gene for the glucan-binding protein of Streptococcus mutans Ingbritt.