Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1991-11-26
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)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
D
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0902-0055
pubmed:author
pubmed:issnType
Print
pubmed:volume
6
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
160-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Sorbitol transport by Streptococcus sanguis 160.
pubmed:affiliation
Department of Oral Microbiology, University of Lund, Malmo, Sweden.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't