Dextransucrase
Mostrando 13-24 de 52 artigos, teses e dissertações.
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13. Purification and Properties of Dextransucrase and Invertase from Streptococcus mutans
Invertase (β-d-fructofuranoside fructohydrolase, EC 3.2.1.26) and dextransucrase (α-1, 6-glucan: d-fructose 2-glucosyltransferase, EC 2.4.1.5) were purified from the culture fluids of Streptococcus mutans by chromatography on Sepharose 6B and diethylaminoethyl-cellulose followed by treatment with hydroxyapatite. Each of the enzyme preparations gave a singl
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14. TEMPERATURE-SENSITIVE DEXTRANSUCRASE SYNTHESIS BY A LACTOBACILLUS
Dunican, L. K. (Cornell University, Ithaca, New York), and H. W. Seeley, Jr. Temperature-sensitive dextransucrase synthesis by a lactobacillus. J. Bacteriol. 86:1079–1083. 1963.—Dextran synthesis was found to be temperature-dependent in Lactobacillus strain RWM-13. Dextran was not formed above 37 C, although growth of cells occurred up to 42 C. Logarithm
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15. Growth and energetics of Leuconostoc mesenteroides NRRL B-1299 during metabolism of various sugars and their consequences for dextransucrase production.
The metabolic and energetic properties of Leuconostoc mesenteroides have been examined with the goal of better understanding the parameters which affect dextransucrase activity and hence allowing the development of strategies for improved dextransucrase production. Glucose and fructose support equivalent specific growth rates (0.6 h-1) under aerobic conditio
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16. Dextransucrase secretion in Leuconostoc mesenteroides depends on the presence of a transmembrane proton gradient.
The relationship between proton motive force and the secretion of dextransucrase in Leuconostoc mesenteroides was investigated. L. mesenteroides was able to maintain a constant proton motive force of -130 mV when grown in batch fermentors at pH values 5.8 to 7.0. The contribution of the membrane potential and the transmembrane pH gradient varied depending on
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17. Streptococcus mutans Dextransucrase: Stimulation of Glucan Formation by Phosphoglycerides
Lysophosphatidylcholine (LPC) and other phosphoglycerides stimulated water-insoluble and water-soluble glucan production by the Streptococcus mutans 6715 dextransucrase (EC 2.4.1.5). LPC stimulated crude extracellular dextransucrase 1.7-fold, the water-insoluble glucan-producing α form of the enzyme 6.5-fold, the water-soluble glucan-producing β form of th
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18. Acceleration of Dextransucrase Activity of Streptococcus mutans by Secretory Immunoglobulin A
The effect of immunoglobulins on the activity of dextransucrase purified from Streptococcus mutans strain HS-6 is described. When human salivary immunoglobulin A (IgA) or colostral IgA, either natured or denatured, was incubated with dextransucrase, the rate of the dextran synthesis was markedly accelerated, whereas human serum IgA or IgG neither accelerated
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19. Insoluble glucan synthesis by Streptococcus mutans serotype c strains.
Both dextransucrase and mutansynthetase activities have been purified from the culture fluids of Streptococcus mutans GS-5 (serotype c). Although homogeneous dextransucrase preparations normally synthesize little insoluble glucan, essentially all of the glucan synthesized by this enzyme in the presence of 1.5 M (NH4)2SO4 was water insoluble. Linkage analysis
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20. Induction and Transcription Studies of the Dextransucrase Gene in Leuconostoc mesenteroides NRRL B-512F
Dextransucrase production by Leuconostoc mesenteroides NRRL B-512F in media containing carbon sources other than sucrose is reported for the first time. Dextransucrases were analyzed by gel electrophoresis and by an in situ activity assay. Their polymers and acceptor reaction products were also compared by 13C nuclear magnetic resonance and high-performance
American Society for Microbiology.
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21. Some Immunochemical Properties of Dextransucrase and Invertase from Streptococcus mutans
Dextransucrase and invertase of some strains of Streptococcus mutans were examined by immunodiffusion with antisera against enzymes purified from strain HS-6 (Bratthall's serotype a). Both antisera cross-reacted with crude enzyme preparations from the other serotype a (strains HS-1 and AHT) and d organisms (strains KIR, OMZ176, and OMZ65) but not with those
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22. Relationship between cell-bound dextransucrase and the agglutination of Streptococcus mutans.
Dextran-induced agglutination of Streptococcus mutans cells is independent of cell-bound dextransucrase activity. Toluene extraction or the presence of Hg2+ or Cu2+ markedly decreased or completely abolished cell-bound dextransucrase activity without adversely affecting dextran-induced cell agglutination. Cells treated by heating at 100 C until cell-bound de
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23. Adherence of Streptococcus mutans to Dextran Synthesized in the Presence of Extracellular Dextransucrase
Live or heat-killed cells of Streptococcus mutans specifically adhere to dextran previously synthesized on glass surfaces by the action of extracellular dextransucrase.
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24. Streptococcus mutans dextransucrase: mode of interaction with high-molecular-weight dextran and role in cellular aggregation.
The interaction between Streptococcus mutans dextransucrase (EC 2.4.1.5) and high-molecular-weight dextran was studied in both the presence and absence of substrate sucrose. Equivalent weight-percent solutions of primer dextrans that differed 200-fold in molecular weight were found to be equally efficient in priming new dextran synthesis. Sodium borohydride