Regulation of dextranase synthesis by <i>Streptococcus mutans</i>

Walker, Gwen J.; Murray, Virginia L.; Morrey-Jones, Jill G.

doi:10.1016/0014-5793(80)81169-0

Cited by 7 publications

(2 citation statements)

References 11 publications

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“…This allowed the use of galactose as a ‘non-sucrose related’ carbon-source for the sucrose-shift experiments. The pH levels (6·1-6.4) of S. salivarius PC-1 cultures grown to an optical density of Klett 75, regardless of the sugar used, were well within the ranges determined by others for optimal GTF (McCabe & Smith, 1973), dextranase (Walker et al ., 1980), FTF (Wenham et al ., 1979), and fructanase (Jacques et al ., 1985b) production.…”

Section: Discussionsupporting

confidence: 80%

“…Under all conditions tested, cell-associated activity for these enzymes was not detected, indicating that both dextranase and fructanase are extracellular enzymes. If an intracellular dextranase exists in this organism, as in related streptococci (Dewar & Walker, 1975; Walker et al ., 1980; Walker et al ., 1981; Russell & Ferretti, 1990), its activity was not measurable under these conditions. Dextranase levels were similar whether the cells were grown in glucose, fructose or galactose; the same held true for fructanase (levanase) levels ().…”

Section: Resultsmentioning

confidence: 99%

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Multilevel control of extracellular sucrose metabolism in Streptococcus salivarius by sucrose

Townsend-Lawman

Bleiweis

1991

Microbiology

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Standardized experimental conditions were established to test the role of sucrose in the regulation and control of its metabolism in Streptococcus sulivcrrius. A fresh isolate of S. salivurius was used. The extracellular dextranase activity of cells grown on sucrose was 10-fold higher than that of cells grown on glucose, fructose or galactose. This activity increased in less than 5 min following the addition of sucrose to galactose-grown cells, a phenomenon which was affected by neither rifampicin nor chloramphenicol which inhibit transcription and translation, respectively. Extracellular fructanase activity was 2-fold higher when cells were grown on sucrose than when they were grown on the other sugars. This increase also occurred within 5 min, but was diminished by transcriptional and translational inhibitors. De nouo synthesis was required for the production of extracellular glucosyltransferase (GTF) activity which, upon the addition of sucrose, became associated with.the cell surface. Conversely, cellassociated fructosyltransferase (FTF) activity appeared to require genetic induction for its production and cellsurface association, but required sucrose for its release from the surface framework. Versatility in the control mechanisms of this complex set of enzymes allows their expression and function to be regulated at several widely separated stages in the life histories of these proteins.

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Section: Discussionsupporting

confidence: 80%

Section: Resultsmentioning

confidence: 99%

Multilevel control of extracellular sucrose metabolism in Streptococcus salivarius by sucrose

Townsend-Lawman

Bleiweis

1991

Microbiology

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An endodextranase inhibitor from batch cultures of Streptococcus,mutans

Hamelik

McCabe

1982

Biochemical and Biophysical Research Communications

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Metabolism of the Polysaccharides of Human Dental Plaque: Release of Dextranase in Batch Cultures of Streptococcus mutans

Walker¹,

Pulkownik²,

Morrey-Jones³

1981

Microbiology

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~~~~ ~Dextranase activity was determined in cell extracts and cell-free filtrates of Streptococcus mutans strains which had been grown in batch culture. Exo-dextranase activity was located chiefly in cell extracts, whereas endodextranase was mainly extracellular. Release of endo-dextranase began early in the exponential phase of growth, and ended when the concentration of residual sugar was low. Thus, dextranase expression was associated with rapidly growing cells, and the yield of dextranase was increased several fold when the initial concentration of D-glucose in the medium was changed from 0.5% to 2%. The endo-dextranase was not stable at pH 5 , and control of the pH of the culture was essential to preserve active dextranase during overnight growth. Strain Ingbritt (serotype c) and serotype d strains were the best dextranase producers; other strains (serotypes a, b, c, e and f) displayed much lower activity. The ability to produce endo-dextranase, and to synthesize a-D-glucans with a high proportion of (1 -3)-linked sequences, appeared to be related properties. The possibility is discussed that the release of two enzymes, namely endodextranase and the D-glucosyltransferase (GTF-I) that synthesizes ( 1 +3)-a-D-glUCan, are factors that contribute to the cariogenicity of S . mutans serotype d.

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Regulation of dextranase synthesis by Streptococcus mutans

Cited by 7 publications

References 11 publications

Multilevel control of extracellular sucrose metabolism in Streptococcus salivarius by sucrose

Multilevel control of extracellular sucrose metabolism in Streptococcus salivarius by sucrose

An endodextranase inhibitor from batch cultures of Streptococcus,mutans

Metabolism of the Polysaccharides of Human Dental Plaque: Release of Dextranase in Batch Cultures of Streptococcus mutans

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