0000000000342388
AUTHOR
Véronique Dartois
Phenolic Acid-Mediated Regulation of the padC Gene, Encoding the Phenolic Acid Decarboxylase of Bacillus subtilis
ABSTRACT In Bacillus subtilis , several phenolic acids specifically induce expression of padC , encoding a phenolic acid decarboxylase that converts these antimicrobial compounds into vinyl derivatives. padC forms an operon with a putative coding sequence of unknown function, yveFG , and this coding sequence does not appear to be involved in the phenolic acid stress response (PASR). To identify putative regulators involved in the PASR, random transposon mutagenesis, combined with two different screens, was performed. PadR, a negative transcriptional regulator of padC expression, was identified. padR is not located in the vicinity of padC , and the expression of padR is low and appears const…
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…
Gene Cloning, Transcriptional Analysis, Purification, and Characterization of Phenolic Acid Decarboxylase from Bacillus subtilis
Phenolic acids, also called substituted cinnamic acids, are important lignin-related aromatic acids and natural constituents of plant cell walls. These acids (particularly ferulic, p-coumaric, and caffeic acids) bind the complex lignin polymer to the hemicellulose and cellulose in plants (1) or are generally esterified with tartaric acid (for example, in grape must, wine, and cider) and can be released as free acids during wine making by some cinnamoyl esterase activities (9). Most often, free phenolic acids are metabolized by different microorganisms into 4-vinyl derivatives and then are eventually reduced into 4-ethyl derivatives (5, 6). Some of these volatile phenols, particularly vinyl …
Cloning of branched chain amino acid biosynthesis genes and assays of alpha-acetolactate synthase activities in Leuconostoc mesenteroides subsp. cremoris.
Abstract A genomic library from Leuconostoc mesenteroides subsp. cremoris (Lmc) in Escherichia coli was screened for α-acetolactate synthase (ALS) activity using a phenotypic test detecting the production of acetolactate or related C 4 derivatives (diacetyl, acetoin or 2,3-butanediol) in the culture. Four recombinant E. coli clones, with plasmids containing overlapping DNA fragments and displaying anabolic ALS activity, were selected. This activity is encoded by an ilvB gene belonging to a putative operon which contains genes highly similar to the genes of the branched chain amino acid (BCAA) operon of Lactococcus lactis subsp. lactis. This putative BCAA operon is not functional as the ilvA…