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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
3
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pubmed:dateCreated |
1991-11-26
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pubmed:abstractText |
Sorbitol metabolism was examined with a sorbitol-fermenting strain (160) of Streptococcus sanguis isolated from the dental plaque of a subject using sorbitol-containing chewing-gum for 4 years. S. sanguis 160 was grown in continuous culture (pH, 7.0; dilution rate, 0.1 h-1) with glucose, sorbitol and nitrogen (sorbitol-excess) limitations. Cells grown with a glucose limitation exhibited low, but detectable, uptake of [14C]-sorbitol and transition to medium limiting in sorbitol resulted in a 5-fold increase in sorbitol uptake. Kinetic data revealed that both glucose and sorbitol-limited cells possessed 2 transport systems for sorbitol (Ks = 3.3-6.7 and 36-64 microM), but continued growth of the organism on limiting sorbitol resulted in the loss of the high-affinity system. Decryptified, sorbitol-limited cells phosphorylated sorbitol in the presence of phosphoenolpyruvate (PEP), but not with ATP, indicating sorbitol transport solely via the PEP phosphotransferase (PTS) system. PEP-dependent activity in glucose-limited and sorbitol-excess cells was 6- and 4-fold lower than that of the sorbitol-limited cells. Uptake of [14C]-sorbitol and activity for Ell for sorbitol [Ellsor] of the PTS in cells in transition from a glucose to sorbitol limitation confirmed the induction of the sorbitol-PTS and the repression of the glucose-PTS in the presence of sorbitol. Cells grown with an excess of sorbitol exhibited very low Ellsor activity. A crossover experiment with membranes and soluble fractions from glucose-, sorbitol- and nitrogen-limited cells of S. sanguis 160 demonstrated the induction of a soluble PTS component in sorbitol-limited cells essential for sorbitol transport via the PTS.(ABSTRACT TRUNCATED AT 250 WORDS)
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
D
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Jun
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pubmed:issn |
0902-0055
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
6
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
160-8
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading | |
pubmed:year |
1991
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pubmed:articleTitle |
Sorbitol transport by Streptococcus sanguis 160.
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pubmed:affiliation |
Department of Oral Microbiology, University of Lund, Malmo, Sweden.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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