Two plasmid-determined restriction and modification systems in Streptococcus lactis

Chopin, Alain; Chopin, Marie-Christine; Moillo-Batt, A; Langella, Philippe

doi:10.1016/0147-619x(84)90033-7

Cited by 390 publications

(143 citation statements)

References 15 publications

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“…Lactococctrs lactis IL1403 (Chopin et al, 1984) and its derivatives, and Escherichia coli TG1 (Gibson, 1984), were grown as described by Bardowski et al (1992). The chemically defined medium (CDM) for L. lactis has been described (Raya et al, 1998 l,S'-GAACGCCTCCAAGAAACAATC-3' ; 2,S'-CGGGAT-CCCGAAATCGGGGTCATGGTG-3' ; 3, S'CAGGAAACA-GCTATGACCGGTCGACGGATCCGGGGG-3' ; 4, 5'-TG-TAAAACGACGGCCAGTGTCACGCGGTGCCACCG-3'; 5, 5'-CAGGAAACAGCTATGACCCGATACCAAGCGAC-TTG-3'; 6, 5'-TGTAAAACGACGGCCAGTCGGGGTCA-TGGTGTCTGC-3' ; 7, 5'-GTGGCTTTGTATGGCTCT-3' ; 8, 5'-CGGGGTCATGGTGTCTGC-3' ; 9, 5'-GGCGTATG-TCACGCGGTGCCACCG-3'.…”

Section: Methodsmentioning

confidence: 99%

Transcription of the trp operon in Lactococcus lactis is controlled by antitermination in the leader region

et al. 1998

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~The regulatory functions of the leader region preceding the Lactococcus lactis trp operon have been studied by mutagenesis analysis. This leader presents striking similarity to 'T-box' leaders found upstream of many Gram-positive aminoacyl-tRNA synthetase genes and some amino acid biosynthesis operons, which are controlled by antitermination through interaction of the leader transcript with cognate uncharged tRNA. A region of the L. lactis leader transcript also contains a series of (GN)AG repeats which, in Bacillus, are involved in the binding of the trp RNA-binding protein (TRAP) which controls trp transcription. A screen was developed for the isolation of regulatory mutants affected in the leader region. All spontaneous mutants contained deletions; point mutations were only obtained after UV-induced mutagenesis. All mutations affected the putative transcription terminator upstream of the trp operon, demonstrating that trp is indeed controlled by transcription antitermination. Keywords INTRODUCTIONAll seven genes required for tryptophan (Trp) biosynthesis form an operon in Lactococcus lactis (Bardowski et al., 1992), which is preceded by a 403-base non-coding leader region (Fig. 1). In the presence of Trp, two small transcripts are produced, corresponding to parts of the leader region : a 290-base transcript, initiated at the Ptrp transcription promoter and arrested close to the putative transcription terminator T1 upstream of the structural genes, and a 160-base transcript, identical to the 3' part of the former, corresponding to a processing product (Raya et al., 1998). Under conditions of Trp starvation, transcription of a third additional transcript is induced 300-to 500-fold. This 8 kb transcript spans the full length of the operon.The trp leader region presents striking structural similarities to a family of leader regions upstream of t Present address: IBB-PAN, Zaklad Biochemii Drobnoustrojow, UI.Pawinskiego SA, 02-106 Warszawa, Poland.Abbreviations: TRAP, trp RNA-binding protein; 6-fTrp, 6-fluorotryptophan.aminoacyl-tRNA synthetase genes and some amino acid biosynthesis operons in a number of Gram-positive bacteria, which are controlled by antitermination . All these leader regions contain a transcription terminator upstream of the coding sequence. The sequence immediately upstream of the terminator, and extending within its 5' part, has the potential to form an alternative, but much less stable, antiterminator structure, in which a 14-base region, called the T-box, is highly conserved. The leader transcripts also have in common conserved stem-loop structures, a single codon, specifying the amino acid expected to regulate expression of the system, and an antiacceptor, complementary to the tRNA amino acid acceptor arm, present within the T-box (Fig. 1). The conservation of these features suggested a regulatory model in which transcription is controlled by a switch between the antiterminator and the terminator form of the leader transcript, mediated by interaction with the cognate uncharged tRNA . It i...

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Section: Methodsmentioning

confidence: 99%

Transcription of the trp operon in Lactococcus lactis is controlled by antitermination in the leader region

et al. 1998

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“…diacetylactis [14] and L. lactis subsp. cremoris MG1363 (lac À , cit À ) [16] cells were grown in batch cultures at 30°C without shaking. M17 broth medium (Oxoid) supplemented with 0.5% glucose (M17G) was adjusted at initial pH 5.5 or 7.0 with HCl acid [13].…”

Section: Bacterial Strains and Growth Mediamentioning

confidence: 99%

Characterization of an oxaloacetate decarboxylase that belongs to the malic enzyme family

et al. 2004

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The citM gene from Lactococcus lactis CRL264 was demonstrated to encode for an oxaloacetate decarboxylase. The enzyme exhibits high levels of similarity to malic enzymes (MEs) from other organisms. CitM was expressed in Escherichia coli, purified and its oxaloacetate decarboxylase activity was demonstrated by biochemical and genetic studies. The highest oxaloacetate decarboxylation activity was found at low pH in the presence of manganese, and the K m value for oxaloacetate was 0.52 % 0.03 mM. However, no malic activity was found for this enzyme. Our studies clearly show a new group of oxaloacetate decarboxylases associated with the citrate fermentation pathway in gram-positive bacteria. Furthermore, the essential catalytic residues were found to be conserved in all members of the ME family, suggesting a common mechanism for oxaloacetate decarboxylation.

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“…The strains used in this study were L. lactis IL1403 (Chopin et al, 1984), L. lactis IL1403 Nis R (Kramer et al, 2004) and L. lactis MG1363 DdltD (Duwat et al, 1997). All strains were grown at 30 uC in M17 (Terzaghi & Sandine, 1975) broth with 0.5 % glucose (GM17) and antibiotics where appropriate (chloramphenicol, 5 mg ml 21 ; nisin, 3000 mg l 21 , when using the Nis R strain of L. lactis).…”

Section: Methodsmentioning

confidence: 99%

Increased d-alanylation of lipoteichoic acid and a thickened septum are main determinants in the nisin resistance mechanism of Lactococcus lactis

et al. 2008

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Nisin is a post-translationally modified antimicrobial peptide produced by Lactococcus lactis which binds to lipid II in the membrane to form pores and inhibit cell-wall synthesis. A nisinresistant (Nis R ) strain of L. lactis, which is able to grow at a 75-fold higher nisin concentration than its parent strain, was investigated with respect to changes in the cell wall. Direct binding studies demonstrated that less nisin was able to bind to lipid II in the membranes of L. lactis Nis R than in the parent strain. In contrast to vancomycin binding, which showed ring-like binding, nisin was observed to bind in patches close to cell-division sites in both the wild-type and the Nis R strains. Comparison of modifications in lipoteichoic acid of the L. lactis strains revealed an increase in D-alanyl esters and galactose as substituents in L. lactis Nis R , resulting in a less negatively charged cell wall. Moreover, the cell wall displays significantly increased thickness at the septum. These results indicate that shielding the membrane and thus the lipid II molecule, thereby decreasing abduction of lipid II and subsequent pore-formation, is a major defence mechanism of L. lactis against nisin.

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Two plasmid-determined restriction and modification systems in Streptococcus lactis

Cited by 390 publications

References 15 publications

Transcription of the trp operon in Lactococcus lactis is controlled by antitermination in the leader region

Transcription of the trp operon in Lactococcus lactis is controlled by antitermination in the leader region

Characterization of an oxaloacetate decarboxylase that belongs to the malic enzyme family

Increased d-alanylation of lipoteichoic acid and a thickened septum are main determinants in the nisin resistance mechanism of Lactococcus lactis

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