Linked Life Data

1658712

Source:http://linkedlifedata.com/resource/pubmed/id/1658712

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1991-12-19
pubmed:abstractText
The parental strain Streptococcus sobrinus (Streptococcus mutans ATCC 27352), which is known to transport, phosphorylate and accumulate xylitol intracellularly as nonmetabolizable xylitol-phosphate (xylitol-sensitive (XS) strain) and its xylitol-resistant (XR) spontaneous mutant were used to further investigate the inhibitory action of xylitol on oral streptococci. Fructose-grown XR cells did not accumulate xylitol-phosphate, indicating that the inducible fructose PTS is incapable of transporting the pentitol. The intracellularly accumulated pentitol-phosphate by the XS cells did not prevent the subsequent uptake and degradation of glucose or fructose, despite a drop in the PEP pool and a 50% inhibition of the glucose but not the fructose catabolism. Intracellular dephosphorylation of the pentitol-phosphate and release of xylitol in the extracellular medium resulted in a rapid decrease of the intracellular level of this nonmetabolizable product. A Mg(++)- or Mn(++)-independent sugar-phosphate hydrolysing activity capable of splitting xylitol-phosphate was demonstrated in both XS and XR strains. Preincubation in the presence of N1-ethylmaleimide (NEM) and xylitol or NEM and fructose resulted in the subsequent inhibition of both xylitol uptake and efflux. The efflux kinetic at various temperatures is compatible with a facilitated diffusion by the phosphotransferase system EIIfru without, however, excluding the existence of an additional exit route, but it excludes a simple diffusion exit process. The results are consistent with the existence of a xylitol futile cycle contributing to the growth inhibition of S. sobrinus by the pentitol without excluding a toxic effect of xylitol-phosphate. Discrepancies in the literature on the action of xylitol on S. mutans could be explained in the light of the evidence presented.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
D
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0902-0055
pubmed:author
pubmed:issnType
Print
pubmed:volume
6
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
41-50
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Intracellular xylitol-phosphate hydrolysis and efflux of xylitol in Streptococcus sobrinus.
pubmed:affiliation
Ecole de Médecine Dentaire, Université Laval, Ste-Foy, Québec, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't