Document Detail

Membrane ATPases and acid tolerance of Actinomyces viscosus and Lactobacillus casei.
MedLine Citation:
PMID:  2445289     Owner:  NLM     Status:  MEDLINE    
Lactobacillus casei ATCC 4646 and Actinomyces viscosus OMZ105E were found to differ markedly in acid tolerance. For example, pH profiles for glycolysis of intact cells in dense suspensions indicated that glycolysis by L. casei had an optimal pH of about 6.0 and that glucose degradation was reduced by 50% at a pH of 4.2. Comparable values for A. viscosus cells were at pHs of about 7.0 and 5.6. The difference in acid tolerance appeared to depend mainly on membrane physiology, and the addition of 40 microM gramicidin to cell suspensions increased the sensitivity of the glycolytic system by as much as 1.5 pH units for L. casei and up to 0.5 pH unit for A. viscosus. L. casei cells were inherently somewhat more resistant to severe acid damage than were A. viscosus cells, in that Mg release from L. casei cells in medium with a pH of 3.0 occurred only after a lag of some 4 h, compared with rapid release from A. viscosus cells. However, the major differences pertinent to the physiology of the organisms appeared to be related to proton-translocating ATPases. Isolated membranes of L. casei had about 3.29 U of ATPase per mg of protein, compared with only about 0.06 U per mg of protein for those of A. viscosus. Moreover, the ATPase of L. casei had a pH optimum for hydrolytic activity of about 5, compared with an optimal pH of about 7 for that of A. viscosus.(ABSTRACT TRUNCATED AT 250 WORDS)
G R Bender; R E Marquis
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Applied and environmental microbiology     Volume:  53     ISSN:  0099-2240     ISO Abbreviation:  Appl. Environ. Microbiol.     Publication Date:  1987 Sep 
Date Detail:
Created Date:  1987-12-14     Completed Date:  1987-12-14     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  7605801     Medline TA:  Appl Environ Microbiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2124-8     Citation Subset:  IM    
Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, New York 14642.
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MeSH Terms
Actinomyces / enzymology*,  metabolism
Adenosine Triphosphatases / metabolism*
Cell Membrane / enzymology
Cell Membrane Permeability
Fluorides / pharmacology
Glycolysis / drug effects
Gramicidin / pharmacology
Hydrogen-Ion Concentration
Lactobacillus casei / enzymology*,  metabolism
Magnesium / metabolism
Grant Support
Reg. No./Substance:
0/Fluorides; 0/Protons; 1405-97-6/Gramicidin; 7439-95-4/Magnesium; EC 3.6.1.-/Adenosine Triphosphatases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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