The role of sucrose in dental biofilm formation and in the protein composition of biofilm matrix formed in situ / Papel da sacarose na formação do biofilme dental e na composição de proteinas da matriz do biofilme formado in situ




Dental caries is a biofilm-dependent oral disease, and fermentable dietary carbohydrates are the key environmental factors involved with its initiation and development. Some hypotheses based on the structure, composition and ion kinetic aspects of biofilm have been suggested to explain the cariogenicity of biofilm formed in the presence of sucrose. Among them, the differential expression of bacteria proteins and the presence and absence of salivary proteins in biofilm formed in the presence and absence of sucrose has been suggested. Thus, this thesis was comprised by two manuscripts. The first discusses the role of sucrose in cariogenic dental biofilm formation and the second evaluates the proteins from biofilm formed in situ in the presence of sucrose. Among the hypotheses to explain the low inorganic concentration in the biofilm, the absence of calcium-binding proteins in biofilm formed in the presence of sucrose can help explain it. In the second study, calcium-binding proteins were identified only in biofilm formed in the absence of sucrose and help explain the higher calcium concentration in biofilm matrix. Proteins from oral microorganisms were also identified and most of them were associated to housekeeping functions, such as energy metabolism, amino acid biosynthesis, translation and stress-related proteins. Different stress-responsive proteins were expressed in the two conditions evaluated, suggesting specific adaptive-response in biofilms formed in the presence and absence of sucrose. Our results show that the characterization and the study of protein function in dental biofilm help explain important aspects involved with the initiation and development of dental carles


polysaccharides biofilme ions proteins proteinas ions polissacarideos saccharose biofilms

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