Linked Life Data

10439409

Source:http://linkedlifedata.com/resource/pubmed/id/10439409

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1999-10-28
pubmed:abstractText
The development of a rapid method for measuring intracellular pH (pHi) in single bacterial cells is described. Lactobacillus delbrueckii subsp. bulgaricus and Listeria innocua were used as test organisms. The method is based upon fluorescence microscopy and ratio imaging of cells stained with carboxyfluorescein succinimidyl ester. After staining, the bacteria were immobilized on a membrane filter and transferred to a closed perfusion chamber, allowing control of the cell environment during analysis. The set-up was optimized with regard to the use of neutral-density filters and background subtraction, for determining the excitation ratio 490 nm/435 nm (R490/435) independent of the excitation light intensity, and to reduce photobleaching. This allowed for time-lapse studies with multiple exposures. To study the pHi of Lb. delbrueckii subsp. bulgaricus and L. innocua in response to different extracellular pH (pHex) values, an in vivo calibration curve was constructed in the pHi range 5.0-8.5. Distinct differences between the two cultures were observed. L. innocua maintained a near-neutral pHi almost independently of pHex (5.0-8.0), whereas the pHi of Lb. delbrueckii subsp. bulgaricus decreased with decreasing pHex. In pure and mixed cultures at pHex 5.0, the pHi values of Lb. delbrueckii subsp. bulgaricus and L. innocua were 6.1 +/- 0.2 and 7.5 +/- 0.2, respectively. This difference in pHi may explain how Lb. delbrueckii subsp. bulgaricus obtains a competitive advantage over L. innocua at low pHex.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1350-0872
pubmed:author
pubmed:issnType
Print
pubmed:volume
145 ( Pt 7)
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1703-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Use of fluorescence ratio imaging for intracellular pH determination of individual bacterial cells in mixed cultures.
pubmed:affiliation
Department of Dairy and Food Science, Royal Veterinary and Agricultural University, Frederiksberg C, Denmark. hsi@kvl.dk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't