Biochemistry

Biography

Biography: Palina Vyhouskaya

Abstract

In oral cavity conditions, cariogenic bacteria   Streptococcus mutans   are characterized by altered   metabolism   compared to cells found in physiological flora. The metabolism of Streptococcus mutans is based on   glycolysis  , which also occurs in presence of oxygen (a phenomenon known as the Warburg effect). The low concentration of oxygen (<2%), i.e., hypoxia inside the biofilm, increases an expression of genes encoding glycolytic enzymes and i nhibits the oxidative  phosphorylation . Pyruvate kinase (PK) , one of the enzymes involved in glycolysis, is considered as an enzyme conditioning the rate of the whole process since it is activated by glucose-6-phosphate, a substrate of glycolysis. Pyruvate kinase  from  S. mutans ATCC and 40 clinical strains was purified, precipitated and estimated  fluorimetrically . Here we revealed the activity, and regulation of PK in mixed bacterial biofilm species and discuss how these properties enable regulation of PK for cariogenic biofilm proliferation and caries pro gression consequently. Clinical strains were isolated from children with caries. Mixed biofilm assay was carried out according to Current Protocols in Microbiology.PK activity was higher  (1.65 mU/mg of protein) in the mixed cariogenic biofilm species compared to the single and mixed physiological biofilm types (1.15 mU/mg of protein vs. 1.33 mU/mg of protein).It was demonstrated that the pyruvate kinase activity is increased in mixed cariogenic biofilm species. Streptococcus mutans are more resistant to glycolytic enzyme inactivation occurring in mixed cariogenic biofilm species (including Streptococcus sobrinus, Lactobacillus acidophilus, and Actinomyces viscosus) compared to mixed physiological biofilm types. Inhibition  of glycolytic enzymes might be an essential step in the reduction of mixed cario genic biofilm species which could be a useful tool in caries prophylaxis.