0000000000477725
AUTHOR
M.e. Lhotte
Mechanism of the Citrate Transporters in Carbohydrate and Citrate Cometabolism in Lactococcus and Leuconostoc Species
ABSTRACT Citrate metabolism in the lactic acid bacterium Leuconostoc mesenteroides generates an electrochemical proton gradient across the membrane by a secondary mechanism (C. Marty-Teysset, C. Posthuma, J. S. Lolkema, P. Schmitt, C. Divies, and W. N. Konings, J. Bacteriol. 178:2178–2185, 1996). Reports on the energetics of citrate metabolism in the related organism Lactococcus lactis are contradictory, and this study was performed to clarify this issue. Cloning of the membrane potential-generating citrate transporter (CitP) of Leuconostoc mesenteroides revealed an amino acid sequence that is almost identical to the known sequence of the CitP of Lactococcus lactis . The cloned gene was exp…
Instability of plasmid-encoded citrate permease in Leuconostoc
M. KIHAL, H. PREVOST, M.E. LHOTTE, D.Q. HUANG AND C. DIVIES. 1996. The conversion from citrate positive (Cit+) to citrate negative (Cit-) phenotype of six strains of Leuconostoc mesetiteroides was followed during growth in milk and buffered or unbuffered MRS medium at 30 or 37°C. High rate of loss of Cit+ phenotype was observed. The Cit- phenotype was found to be linked to the loss of 22 to 23 kb plasmids. All Cit- mutants isolated from Leuc. mesenteroides subsp. cremoris 195 reverted spontaneously to the Cit+ phenotype. Hybridization experiments using a 0.8 kb fragment of the citP gene of Leuc. mesenteroides showed that all the plasmids which were lost in Cit- mutants encoded for a citrate…