Linked Life Data

10378087

Source:http://linkedlifedata.com/resource/pubmed/id/10378087

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1999-8-20
pubmed:abstractText
Free intracellular Ca2+ ([Ca2+]i) in Escherichia coli was measured using the bioluminescent protein aequorin. Overall, the bacteria maintained a tight control on their free [Ca2+]i. The results indicated a slow Ca2+ influx, the magnitude of the initial rise in free [Ca2+]i being dependent upon the concentrations of external Ca2+. This was followed by the slow removal of free Ca2+ until normal levels were restored. Specifically, addition of external Ca2+ (0.25-10 mM) resulted in a gradual rise in intracellular free Ca2+ from a basal level of approximately 272 nM, maximally reaching a peak of 0.85-5.4 microM within 30-40 min. This was followed by a slow fall over the next 30 min, culminating in an oscillatory pattern of free [Ca2+]i (range 0.3-0.7 microM for 0.25 mM external Ca2+). In the presence of EGTA, free [Ca2+]i was dramatically reduced. Neither the influx of Ca2+ nor restoration of intracellular free Ca2+ required protein synthesis. Moreover, preincubation with Ca2+ increased the rising phase of intracellular Ca2+ in response to further exposure to external Ca2+. This was further evidence against a specific adaptation process such as the synthesis of calcium exporters. A putative Ca2+ influx channel was demonstrated in stationary phase cells in particular, which could be blocked by La3+. This channel was consistent with the voltage-activated poly-3-hydroxybutyrate/polyphosphate Ca2+ channels previously detailed by Reusch et al. [23] Even in the presence of La3+, however, the free [Ca2+]i of log phase and stationary phase bacteria still increased two-fold over resting values in response to external Ca2+. This suggested the presence of at least two Ca2+ influx processes, one inhibited by La3+ and the other not.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0143-4160
pubmed:author
pubmed:issnType
Print
pubmed:volume
25
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
265-74
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Slow changes in cytosolic free Ca2+ in Escherichia coli highlight two putative influx mechanisms in response to changes in extracellular calcium.
pubmed:affiliation
Department of Medical Biochemistry, University of Wales College of Medicine, Cardiff, UK. joneshe3@cardiff.ac.uk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't