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Campoy S, Mazón G, Fernández de Henestrosa AR, Llagostera M, Monteiro PB, Barbé J. A new regulatory DNA motif of the gamma subclass Proteobacteria: identification of the LexA protein binding site of the plant pathogen Xylella fastidiosa. MICROBIOLOGY (READING, ENGLAND) 2002; 148:3583-3597. [PMID: 12427949 DOI: 10.1099/00221287-148-11-3583] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Escherichia coli LexA protein is the repressor of a gene network whose members are directly involved in the repair of damaged DNA and in the survival of bacterial cells until DNA lesions have been eliminated. The lexA gene is widely present in bacteria, although the sequences of only three LexA-binding sites are known: Gram-positive, alpha Proteobacteria and some members of gamma Proteobacteria represented by E. coli. Taking advantage of the fact that the genome sequence of the plant-pathogenic bacterium Xylella fastidiosa has been determined, its lexA gene has been cloned and overexpressed in E. coli to purify its product. After demonstration that X. fastidiosa lexA and recA genes are co-transcribed, gel mobility shift assays and directed mutagenesis experiments using the promoter of the lexA-recA transcriptional unit demonstrated that the X. fastidiosa LexA protein specifically binds the imperfect palindrome TTAGN(6)TACTA. This is the first LexA binding sequence identified in the gamma Proteobacteria differing from the E. coli-like LexA box. Although a computational search has revealed the presence of TTAGN(6)TACTA-like motifs upstream of X. fastidiosa genes other than lexA, X. fastidiosa LexA only binds the promoter of one of them, XF2313, encoding a putative DNA-modification methylase. Moreover, X. fastidiosa LexA protein does not bind any of the other genes whose homologues are regulated by the LexA repressor in E. coli (uvrA, uvrB, ssb, ruvAB, ftsK, dinG, recN and ybfE). RT-PCR quantitative analysis has also demonstrated that lexA-recA and XF2313 genes, as well as the X. fastidiosa genes which are homologues to those of E. coli belonging to the LexA regulon, with the exception of ssb, are DNA damage-inducible in X. fastidiosa.
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Ferrer M, Sánchez-Lamar A, Luís Fuentes J, Barbé J, Llagostera M. Antimutagenic mechanisms of Phyllanthus orbicularis when hydrogen peroxide is tested using Salmonella assay. Mutat Res 2002; 517:251-4. [PMID: 12034326 DOI: 10.1016/s1383-5718(02)00064-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Phyllanthus orbicularis is a medicinal plant, endemic to Cuba, whose aqueous extract has proven antiviral properties and antimutagenic activities against aromatic amines and hydrogen peroxide. In addition, this plant extract presents antioxidant activity. In this paper, using the Salmonella assay with the experimental approaches of co-incubation, pre- and post-treatments, it is shown that the P. orbicularis extract protects bacterial cells from oxidative damage and mutation by some intracellular mechanism, irrespective of its antioxidant activity.
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Bosch M, Garrido E, Llagostera M, Pérez de Rozas AM, Badiola I, Barbé J. Pasteurella multocida exbB, exbD and tonB genes are physically linked but independently transcribed. FEMS Microbiol Lett 2002; 210:201-8. [PMID: 12044675 DOI: 10.1111/j.1574-6968.2002.tb11181.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The exbB, exbD and tonB genes of the Pasteurella multocida animal pathogen have been cloned by complementation of an Escherichia coli tonB mutant. Despite these three genes being physically linked, RT-PCR analysis, lacZ transcriptional fusions and construction of insertional mutants have demonstrated that they do not constitute an operon, but rather are transcribed independently from each other. Furthermore, expression of these three genes is under iron control as revealed by lacZ fusions and Fur titration assay analysis. Moreover, each of these three genes is necessary for the virulence of P. multocida cells and all of them contribute equally to the infectious process of this microorganism.
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MESH Headings
- Bacterial Proteins/genetics
- Bacterial Proteins/physiology
- Cloning, Molecular
- Escherichia coli/genetics
- Escherichia coli Proteins
- Gene Expression Regulation, Bacterial/drug effects
- Gene Order/genetics
- Genes, Bacterial/genetics
- Genes, Bacterial/physiology
- Genetic Complementation Test
- Genetic Linkage/genetics
- Iron/pharmacology
- Lethal Dose 50
- Membrane Proteins/genetics
- Membrane Proteins/physiology
- Multigene Family/genetics
- Mutation
- Pasteurella multocida/genetics
- Pasteurella multocida/pathogenicity
- Promoter Regions, Genetic/genetics
- RNA, Bacterial/analysis
- RNA, Bacterial/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Analysis, DNA
- Transcription, Genetic/drug effects
- Transcription, Genetic/genetics
- Virulence/genetics
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Ferrer M, Sánchez-Lamar A, Fuentes JL, Barbé J, Llagostera M. Studies on the antimutagenesis of Phyllanthus orbicularis: mechanisms involved against aromatic amines. Mutat Res 2001; 498:99-105. [PMID: 11673075 DOI: 10.1016/s1383-5718(01)00270-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Phyllanthus orbicularis is a medicinal plant, endemic to Cuba, whose aqueous extract has proven antiviral properties. This plant extract is being studied for treatment of viral diseases in animals and humans. Antimutagenic activities of this plant aqueous extract have been investigated as an additional and possible valuable property. Antimutagenesis was assayed against the mutagenic activity of m-phenylenediamine (m-PDA), 2-aminofluorene (2-AF), 1-aminopyrene (1-AP), 2-aminoanthracene (2-AA) and 9-aminophenantrene (9-AP) in Salmonella typhimurium (S. typhimurium) YG1024, in different co-treatment approaches. This plant extract produced a significant decrease of the mutagenesis mediated by these aromatic amines (AA) in the following order: m-PDA>2-AA>2-AF>9-AP>1-AP. Interactions with S9 enzymes and transformation of promutagenic amines and their mutagenic metabolites by chemical reactions to non-mutagenic compounds are proposed as possible mechanisms of antimutagenesis. Mutagenesis mediated by m-PDA was almost completely abolished when S9 mixture was co-incubated with the plant extract during 40 min, previous to the addition of the m-PDA and bacterial cells to the assay. Similar results were found with 2-AA and 1-AP, but the reduction of the mutation rate was not so dramatic. In contrast, the most significant antimutagenic effect against 2-AF and 9-AP was seen when these chemicals were co-incubated with the plant extract, before addition of the S9 mixture and bacterial cells to the assay. Therefore, inhibition or competition for S9 enzymes seems to be the main antimutagenic mechanism of this plant extract against m-PDA, 2-AA and 1-AP, whilst a chemical modification of 2-AF and 9-AP into non-promutagenic derivatives is likely to be the main mechanism of antimutagenesis against both compounds.
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Cárdenas M, Fernández de Henestrosa AR, Campoy S, Perez de Rozas AM, Barbé J, Badiola I, Llagostera M. Virulence of Pasteurella multocida recA mutants. Vet Microbiol 2001; 80:53-61. [PMID: 11278123 DOI: 10.1016/s0378-1135(00)00372-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In order to determine the role of the RecA protein in the virulence of Pasteurella multocida, a recA mutant was constructed and used in studies of virulence and competition in relation to wild-type strain. To achieve this, firstly, the recA gene was isolated and sequenced, showing an Escherichia coli-like SOS box and encoding a protein of 354 amino acids which has the closest identity with the Haemophilus influenzae RecA protein. Further, the recA mutant was constructed, by inactivating this gene by single recombination of a suicide plasmid containing an internal region of the P. multocida recA gene, and shown to be more sensitive to UV radiation than the parental strain. The P. multocida mutant was slightly attenuated in virulence, as indicated by the LD(50), the time of death of infected animals, and a failure to compete with the wild-type strain in mixed infections. Compared to the parent strain, the mutant had a similar growth rate but a longer lag phase. These data suggest that the diminished virulence of the recA mutant as well as its failure in competition were more a consequence of the long lag phase rather than a direct effect of the inactivation of the recA gene on genes involved in virulence.
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Cárdenas M, Barbé J, Llagostera M, Miró E, Navarro F, Mirelis B, Prats G, Badiola I. Quinolone resistance-determining regions of gyrA and parC in Pasteurella multocida strains with different levels of nalidixic acid resistance. Antimicrob Agents Chemother 2001; 45:990-1. [PMID: 11270370 PMCID: PMC90412 DOI: 10.1128/aac.45.3.990-991.2001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Chiapella C, Cárdenas M, Barbé J, Llagostera M. Molecular analysis at the hisD3052 allele of S. typhimurium of mutations induced by aromatic amines, activated by mixed-function oxidases from plants. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2001; 38:80-82. [PMID: 11473391 DOI: 10.1002/em.1053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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58
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Chiapella C, Radovan RD, Moreno JA, Casares L, Barbé J, Llagostera M. Plant activation of aromatic amines mediated by cytochromes P450 and flavin-containing monooxygenases. Mutat Res 2000; 470:155-60. [PMID: 11027970 DOI: 10.1016/s1383-5718(00)00098-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To know the mechanisms involved in the activation of promutagenic aromatic amines mediated by plants, we used Persea americana S117 system (S117) for the activation of 2-aminofluorene (2-AF) and m-phenylenediamine (m-PDA) in Ames assays. In these assays, the effect of the diphenylene iodonium (DPI), an inhibitor of flavin-containing monooxygenases (FMOs), of the 1-aminobenzotriazole (1-ABT), an inhibitor of cytochromes P450 (cyt-P450s) and of the methimazole, a high-affinity substrate for FMOs, was studied. The efficacy of both inhibitors and of the methimazole was verified to find that they did partially inhibit the mutagenesis of both aromatic amines, activated with rat liver S9. Similarly, both inhibitors and methimazole did produce a significant decrease in 2-AF and m-PDA mutagenesis, when the activation system was S117, indicating that, similar to what occurs in mammalian systems, plant FMOs and cyt-P450s can metabolize aromatic amines to mutagenic product(s). However, the affinity of both FMOs and cyt-P450s of plant for 2-AF and m-PDA was different. Data obtained indicate that the activities of plant FMOs must be the main enzymatic system of m-PDA activation while, in 2-AF activation, plant cyt-P450s have the most relevant activities. In addition, peroxidases of the S117 system must contribute to 2-AF activation and some isoforms of FMOs and/or cyt-P450s of the S117 system, uninhibited by the inhibitors used, must be the responsible for a partial activation of m-PDA.
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Fuentes JL, Capetillo N, Ferrer M, Padrón E, Altanés S, Llagostera M. Radioprotective effect of sodium diethyldithiocarbamate (DDC) and S-2-aminoethyl-isothioronicadenosin-5-triphosphate (adeturon) in gamma-irradiated Escherichia coli cells. Mutat Res 1998; 422:339-45. [PMID: 9838185 DOI: 10.1016/s0027-5107(98)00166-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The effect of sodium diethyldithiocarbamate (DDC) and S-2-aminoethyl-isothiouronicadenosin-5-triphosphate (adeturon) in the induction of Escherichia coli SOS response promoted by gamma-irradiation was studied by measuring the induction of sulA gene and the induction of lambda prophage. Furthermore, as a way of measure the exonuclease activity in gamma-irradiated cells in the presence or absence of both compounds, the DNA degradation was determined. Adeturon did not affected DNA degradation, but inhibited the induction of the SOS functions studied. On the contrary, DDC inhibited DNA degradation as well as the induction of the sulA gene, but enhanced lambda induction in E. coli lysogenic strains. These results indicate that both compounds diminish the DNA damage produced by gamma-irradiation and also suggest that the mechanisms of radioprotection must be different. Thus, radioprotection mediated by DDC should involve free hydroxyl radical scavenging and a minor activity of exonuclease. The enhancement of phage induction in E. coli cells that DDC produces could be attributed to its quelant effect and this would not be not probably directly related to radioprotection. Adeturon, as thiols, may serve also as scavenging agent of free hydroxyl radicals, diminishing indirectly the DNA damage level. In addition, adeturon must interact with DNA in the same form that other aminothiol compounds do it. This interaction, mediated by amino groups of adeturon, may serve to concentrate these compounds near of the DNA damage site, increasing the potential for the thiol portion of the molecule to donate hydrogen, decreasing the damage level on DNA molecule. However, adeturon do not modify the exonuclease activity. Some topic about the possible clinical application of both compounds are discussed.
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60
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Chiapella C, Moreno JA, Radovan RD, Gaubert N, Llagostera M. Activation of arylamines to mutagenic product(s) by two in vitro plant systems. Mutat Res 1997; 394:45-51. [PMID: 9434842 DOI: 10.1016/s1383-5718(97)00122-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Plant activation of three isomers of phenylenediamine o- m- and p-phenylenediamine, has been studied. Two in vitro plant systems have been used: Persea americana S117 with mixed-function oxidase (MFO) and peroxidase activities, and Zea mays S9 which contains only peroxidase activity. As genetic endpoint, the classical Salmonella tester strains. TA98 and TA100, their derivatives with high O-acetyltransferase levels (YG1024 and YG1029, respectively) and TA98/1.8-DNP6, deficient in this enzyme, have been assayed. Of the three isomers studied, only m-PDA was activated to mutagenic product(s) by both plant systems. This activation required the bacterial O-acetyltransferase activity to give frameshift mutagenic product(s), detected in TA98 and YG1024 strains. In all the assays the P americana system was more potent than the Z. mays system in activating m-PDA. A slight increase of the number of YG1029 revertants was detected when m-PDA was activated by P. americana, suggesting that this compound can be also converted into ultimate mutagenic product(s) that induce base-pair substitutions. m-PDA activation by Z. mays was dependent on the peroxidase activity of this system, but the activation produced by P. americana was totally dependent on MFOs, because a total inhibition of the mutagenic response was found when these activities were inhibited. In addition, the P. americana system was more potent in generating proximal mutagenic forms from m-PDA than S9 from non-induced rat liver, although S9 from Aroclor 1254-induced Sprague-Dawley male rats was the most potent system in the m-PDA activation. These results indicate that the P. americana system can be useful in determining the role of mixed-function oxidases in plant activation of xenobiotics.
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61
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Clerch B, Rivera E, Llagostera M. Identification of a pKM101 region which confers a slow growth rate and interferes with susceptibility to quinolone in Escherichia coli AB1157. J Bacteriol 1996; 178:5568-72. [PMID: 8824598 PMCID: PMC178392 DOI: 10.1128/jb.178.19.5568-5572.1996] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The effect of plasmid pKM101 on the survival of Escherichia coli AB1157, growing in minimal medium, in the presence of a 4-quinolone DNA gyrase inhibitor was investigated. The presence of this plasmid decreased susceptibility to the quinolone ciprofloxacin, whereas mucAB genes present in a multicopy plasmid did not. The same effect of pKM101 was detected in a recA430 mutant, confirming that it was not really related to the SOS response. In contrast, when survival assays were performed under amino acid starvation conditions, pKM101 did not confer protection against ciprofloxacin. All of these results indicated that the synthesis of a product(s), different from MucAB, which was encoded by the plasmid pKM101 increased the rate of survival of the AB1157 strain in the presence of quinolone. To identify the gene(s) responsible for this phenotype, several plasmid derivatives carrying different portions of pKM101 were constructed. The 2.2-kb region containing korB, traL, korA, and traM genes was sufficient to decrease susceptibility to quinolone. This plasmidic fragment also made the AB1157 host strain grow more slowly (the Slo phenotype). Moreover, the suppression of the Slo phenotype by addition of adenine to the cultures abolished the decreased susceptibility to quinolone. These results are evidence that the protection against quinolone conferred by this region of pKM101 in strain AB1157 is a direct consequence of the slow growth rate.
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Rueff J, Chiapella C, Chipman JK, Darroudi F, Silva ID, Duverger-van Bogaert M, Fonti E, Glatt HR, Isern P, Laires A, Léonard A, Llagostera M, Mossesso P, Natarajan AT, Palitti F, Rodrigues AS, Schinoppi A, Turchi G, Werle-Schneider G. Development and validation of alternative metabolic systems for mutagenicity testing in short-term assays. Mutat Res 1996; 353:151-76. [PMID: 8692190 DOI: 10.1016/0027-5107(95)00246-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We present here the results obtained within the framework of an EU funded project aimed to develop and validate alternative metabolic activating systems to be used in short-term mutagenicity assays, in order to reduce the use of laboratory animals for toxicology testing. The activating systems studied were established cell lines (Hep G2, CHEL), genetically engineered V79 cell lines expressing specific rat cytochromes P450, erythrocyte-derived systems, CYP-mimetic chemical systems and plant homogenates. The metabolically competent cell lines were used as indicator cells for genotoxic effects as well as for the preparation of external activating systems using other indicator cells. The following endpoints were used: micronuclei, chromosomal aberrations and sister chromatid exchanges, mutations at the hprt locus, gene mutations in bacteria (Ames test), unscheduled DNA synthesis and DNA breaks detected in the comet assay. All metabolic systems employed activated some promutagens. With some of them, promutagens belonging to many different classes of chemicals were activated to genotoxicants, including carcinogens negative in liver S9-mediated assays. In other cases, the use of the new activating systems allowed the detection of mutagens at much lower substrate concentrations than in liver S9-mediated assays. Therefore, the alternative metabolizing systems, which do not require the use of laboratory animals, have a substantial potential in in vitro toxicology, in the basic genotoxicity testing as well as in the elucidation of activation mechanisms. However, since the data basis is much smaller for the new systems than for the activating systems produced from subcellular liver preparations, the overlapping use of both systems is recommended for the present and near future. For example, liver S9 preparations may be used with some indicator systems (e.g., bacterial mutagenicity), and metabolically competent mammalian cell lines may be used with other indicator systems (e.g., a cytogenetic endpoint) in a battery of basic tests.
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63
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Clerch B, Garriga X, Torrents E, Rosales CM, Llagostera M. Construction and characterization of two lexA mutants of Salmonella typhimurium with different UV sensitivities and UV mutabilities. J Bacteriol 1996; 178:2890-6. [PMID: 8631678 PMCID: PMC178025 DOI: 10.1128/jb.178.10.2890-2896.1996] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Salmonella typhimurium has a SOS regulon which resembles that of Escherichia coli. recA mutants of S. typhimurium have already been isolated, but no mutations in lexA have been described yet. In this work, two different lexA mutants of S. typhimurium LT2 have been constructed on a sulA background to prevent cell death and further characterized. The lexA552 and lexA11 alleles contain an insertion of the kanamycin resistance fragment into the carboxy- and amino-terminal regions of the lexA gene, respectively. SOS induction assays indicated that both lexA mutants exhibited a LexA(Def) phenotype, although SOS genes were apparently more derepressed in the lexA11 mutant than in the lexA552 mutant. Like lexA(Def) of E. coli, both lexA mutations only moderately increased the UV survival of S. typhimurium, and the lexA552 strain was as mutable as the lexA+ strain by UV in the presence of plasmids encoding MucAB or E. coli UmuDC (UmuDCEc). In contrast, a lexA11 strain carrying any of these plasmids was nonmutable by UV. This unexpected behavior was abolished when the lexA11 mutation was complemented in trans by the lexA gene of S. typhimurium. The results of UV mutagenesis correlated well with those of survival to UV irradiation, indicating that MucAB and UmuDCEc proteins participate in the error-prone repair of UV damage in lexA552 but not in lexA11. These intriguing differences between the mutagenic responses of lexA552 and lexA11 mutants to UV irradiation are discussed, taking into account the different degrees to which the SOS response is derepressed in these mutants.
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Clerch B, Bravo JM, Llagostera M. Efficiency of MucAB and Escherichia coli UmuDC proteins in quinolone and UV mutagenesis in Salmonella typhimurium: effect of MucA and UmuD processing. Mutat Res 1996; 349:201-8. [PMID: 8600351 DOI: 10.1016/0027-5107(95)00179-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The role of MucAB and Escherichia coli UmuDC proteins in mutagenesis by 4-quinolone (4-Q) compared to that in UV mutagenesis has been studied in hisG428 Salmonella typhimurium strains. A low-copy plasmid carrying mucAB genes, but not umuDC, promotes reversion of the hisG428 mutation by the 4-Q ciprofloxacin. In contrast, a umuDC plasmid mediates the reversion of hisG428 by UV, although less efficiently than a mucAB one. In addition, a unique copy of mucAB genes is enough to promote UV mutagenesis, whereas, several copies of them are required to detect ciprofloxacin mutagenesis. Therefore, the mutagenic repair of quinolone damage by MucAB proteins is not a very efficient process. The presence of an umuD'C plasmid but not a mucA'B one, slightly increases the reversion of the hisG428 mutation by ciprofloxacin and this finding is further discussed. In contrast, MucA'B are still more active than UmuD'C proteins in UV mutagenesis. These results suggest that the enhanced processing of MucA compared to UmuD would not explain all functional differences between MucAB and UmuDC proteins in the error-prone DNA repair.
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65
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Clerch B, Bravo JM, Llagostera M. Analysis of the ciprofloxacin-induced mutations in Salmonella typhimurium. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 1996; 27:110-115. [PMID: 8603664 DOI: 10.1002/(sici)1098-2280(1996)27:2<110::aid-em6>3.0.co;2-k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The mutagenic events induced by ciprofloxacin, a potent antimicrobial agent, have been characterized. For this, a battery of His mutants of Salmonella typhimurium (hisG428, his G46, His C9070, and his G1775 targets) that detects the six possible transitions and transversions [Levin and Ames (1986): Environ Mutagen 8:9-28] and two additional His strains (hisC3076 and his D3052 targets) carrying frameshift mutations have been used. Our results indicate that GC-TA transversions are the major base-pair substitution induced by ciprofloxacin and that GC-At transitions are also produced, but to a lesser degree. However, we cannot discard the fact that At-Ta transversions are also induced. In addition, the data indicate that the mutational specificity of ciprofloxacin depends on the location of the target. Intragenic base-pair substitutions are the most frequent mutations at the hisG428 target when it is on the chromosome, whereas 3 or 6 base-pair deletions are the major mutagenic events when this target is on the plasmid pAQ1. We have shown that ciprofloxacin also induces deletions/insertions at the hisC3076 and hisD3052 frameshift targets. Therefore, this inhibitor of DNA gyrase promotes a wide pattern of mutations including different kinds of base-pair substitutions, 3 or 6 base-pair deletions, and insertions/deletions resulting in frameshifts. All of these mutagenic events require the MucAb proteins involved in the error-prone repair, with the exception of base-pair insertions/deletions at the hisD3052 target, which are independent of the presence of plasmid pKM101.
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66
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Chiapella C, Ysern P, Riera J, Llagostera M. A plant metabolic activation system from Persea americana with cytochrome P450-dependent and peroxidase activities. Mutat Res 1995; 329:11-8. [PMID: 7770073 DOI: 10.1016/0027-5107(95)00015-b] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Microsomal fractions from different tissues of various plants (potato, cauliflower, aubergine, avocado pear, courgette, cucumber, banana, kiwi and strawberry) were prepared and their content of cytochrome P-450 (cyt-P450) determined. A S117 fraction from Persea americana (avocado pear) presented the highest content of cyt-P450. As a consequence of these data, we have developed and characterized this fraction as a plant metabolic activation system. The P. americana S117, used in this work, contains 0.75 +/- 0.04 mg of protein per ml, 0.788 +/- 0.078 nmol of cyt-P450 per mg of protein and has a peroxidase activity of 0.036 +/- 0.005 (nmol tetraguaiacol/micrograms protein/min). The P. americana cyt-P450 remained stable during at least 60 days, stored at -80 degrees C. This fraction activated 2-aminofluorene to a mutagenic product in S. typhimurium TA98, while it had no effect on the benzo[a]pyrene activation. The treatment of the P. americana S117 with CO, the addition of diethyldithiocarbamate (DETC) or the absence of a NADPH-generating system in the activation mix, produced a partial inhibition of the 2-aminofluorene activation. Both peroxidase activity and a cyt-P450-dependent activity are assumed to be involved in the activation of this chemical mediated by P. americana S117.
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67
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Sampedro F, Ruiz van Haperen VWT, Izquierdo MA, Vicens M, Santaló P, Pueyo M, Llagostera M, Marcuello E, Andrés LD. Preclinical studies with new pyrrolidine platinum(II) compounds. Eur J Med Chem 1995. [DOI: 10.1016/0223-5234(96)88260-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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68
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Ysern P, Riera J, Sitjes J, Llagostera M. Activation of 4-nitro-o-phenylenediamine by the S2 fraction of Zea mays to mutagenic product(s). Mutat Res 1994; 312:25-31. [PMID: 7507213 DOI: 10.1016/0165-1161(94)90005-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Studies on plant metabolic activation with the S2 fraction from Zea mays have been developed. The 4-nitro-o-phenylenediamine (NOP) activation by S2 has been analyzed with the Ames test as a short-term assay. The NOP mutagenic potency was increased two-fold by S2, while rat liver S9 produced the contrary effect. The presence of a NADPH-generating system and the treatment of S2 with CO do not modify S2 activation of NOP. In this fraction, neither cytochrome P450 nor some enzymatic activities depending on cyt-P450 (aniline hydroxylase and aminopyrine demethylase) were detected. Therefore, the enhancement of NOP mutagenic potency by S2 is independent of the mixed-function oxidase system. On the other hand, inhibitors of the peroxidase activity such as N-acetyl-p-aminophenol caused a partial inhibition of S2 activation of NOP. Likewise, diethyldithiocarbamate produced both a reduction of the S2 peroxidase activity in biochemical assays and a partial inhibition of S2 activation of NOP. Moreover, it was possible to find a direct correlation between the activity of peroxidase per plate of both the S2 fraction and horseradish peroxidase and the number of revertants induced by NOP in the TA98 strain. On the basis of these results, we report that a HRP-like peroxidase activity must be the main pathway of NOP activation by the plant metabolic activation system studied in this work.
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Sampedro F, Molins-Pujol AM, Ruiz JI, Santaló P, Bonal J, Pueyo M, Llagostera M, Sánchez-Ferrando F. Synthesis and activity studies in vitro and in vivo of a new series of malonato-platinum(II) complexes containing sulfide and phosphine ligands. Eur J Med Chem 1992. [DOI: 10.1016/0223-5234(92)90139-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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70
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Clerch B, Barbé J, Llagostera M. The role of the excision and error-prone repair systems in mutagenesis by fluorinated quinolones in Salmonella typhimurium. Mutat Res 1992; 281:207-13. [PMID: 1371844 DOI: 10.1016/0165-7992(92)90010-f] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Patterns of reversion produced by ciprofloxacin, enoxacin and ofloxacin in Salmonella typhimurium strains carrying the hisG428 ochre mutation have been studied. These fluorinated quinolones produce a significant increase in reversion of this mutation, even when it is located on the chromosome. Nevertheless, reversion is higher when the hisG428 mutation is on the multicopy plasmid pAQ1 than when it is on the chromosome. Reversion of hisG428 induced by fluorinated quinolones is abolished both in a uvrB genetic background and in the absence of the plasmid pKM101. Therefore, mutagenesis produced by fluorinated quinolones in the Salmonella mutagenicity assay is significantly affected by both the excision repair and the error-prone repair systems. Furthermore, fluorinated quinolones are also detected as moderate mutagens with the base substitution hisG46 mutation when both repair systems are functional in the tester strain.
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71
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Garí E, Ollé M, Gibert I, Llagostera M, Barbé J. Isolation and characterization of a recombination defective-dependent bacteriophage ofRhodobacter sphaeroides. Curr Microbiol 1992. [DOI: 10.1007/bf01568980] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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72
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Sitjes J, Ysern P, Barbe J, Llagostera M. Induction of ribonucleoside diphosphate reductase gene transcription by chemicals in Escherichia coli. Mutagenesis 1992; 7:47-9. [PMID: 1635455 DOI: 10.1093/mutage/7.1.47] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A fusion between the promoter of the nrdA gene of Escherichia coli and the lacZ gene has been constructed, and the induction of nrdA gene expression by 20 organic and 20 inorganic chemicals has been studied. The inducing compounds of the SOS genes, such as bleomycin, captan, ciprofloxacin, enoxacin, hydroxyurea, N-methyl-N'-nitro-N-nitrosoguanidine, mitomycin C, nalidixic acid, ofloxacin and hexavalent chromium compounds also trigger the expression of the nrdA gene. Other chemicals such as aluminium, manganese and zinc salts, reported as negative in the SOS Chromotest, are also inducers of the nrdA gene. These results suggest that ribonucleoside diphosphate reductase transcription is increased by chemicals able to either block DNA synthesis or to alter the enzymes participating in the DNA replication. Induction of nrdA gene is an effect to be further considered in the study of alterations produced by physical or chemical treatments which act upon DNA metabolism.
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73
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Casado C, Llagostera M, Barbé J. Expression ofnrdAandnrdBgenes ofEscherichia coliis decreased under anaerobiosis. FEMS Microbiol Lett 1991. [DOI: 10.1111/j.1574-6968.1991.tb04432.x-i1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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74
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Casado C, Llagostera M, Barbé J. Expression of nrdA and nrdB genes of Escherichia coli is decreased under anaerobiosis. FEMS Microbiol Lett 1991; 67:153-7. [PMID: 1778429 DOI: 10.1016/0378-1097(91)90346-c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
By using plasmid nrdA-lacZ, nrdAB-lacZ, and nrdB-lacZ gene fusions, the expression of nrdA and nrdB genes of Escherichia coli under anaerobiosis has been studied. The results obtained show that cells of E. coli growing under either fermentative or nitrate respiring conditions present a lower basal level of both nrdA and nrdB genes transcription from the nrdPA promoter. On the other hand, transcription of the nrdB gene from the internal nrdPB promoter was not affected by the absence of oxygen. Moreover, the DNA damage-mediated inducing factor of these nrd genes was the same in both aerobic and anaerobic cultures.
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75
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Sampedro F, Ruiz J, Molins-Pujol A, Santaló P, Moranta C, Pueyo M, Llagostera M, Bonal J. In vitro and in vivo studies with new platinum complexes containing ammine, sulfide, phosphine and another groups as ligands. J Inorg Biochem 1991. [DOI: 10.1016/0162-0134(91)84570-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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76
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Sampedro F, Molins-Pujol AM, Bonal J, Barbé J, Garrido S, Pueyo M, Llagostera M, Sánchez-Ferrando F. Sulfide and phosphine ligands in carboplatin analogs. Eur J Med Chem 1991. [DOI: 10.1016/0223-5234(91)90150-l] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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77
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Pueyo M, Sampedro F, Bonal J, Barbé J, Llagostera M. Role of the postreplication repair pathway in the repair of damaged DNA by cisplatin. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/0165-1161(90)90182-n] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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78
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Ysern P, Clerch B, Castańo M, Gibert I, Barbé J, Llagostera M. Induction of SOS genes in Escherichia coli and mutagenesis in Salmonella typhimurium by fluoroquinolones. Mutagenesis 1990; 5:63-6. [PMID: 2158613 DOI: 10.1093/mutage/5.1.63] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The induction of several SOS genes of Escherichia coli by fluoroquinolones has been studied. Three different SOS gene fusions (recA::lacZ, umuC::lacZ and sulA::lacZ) have been introduced into the E.coli MC1061 strain to study the induction of these SOS genes in the same genetic background. Data on the basal level of expression of these fusions, as well as their induction by mitomycin C and N-methyl-N'-nitro-N-nitrosoguanidine are presented. Using these strains, we have found that, like nalidixic acid, ofloxacin, enoxacin and ciprofloxacin are strong inducers of the SOS genes tested, umuC gene expression being the highest. Furthermore, fluoroquinolones produced a significant increase in the reversion of the base substitution hisG428 mutation in the TA102 Salmonella tester strain, while no effect was found in strains TA98, TA100, TA1537 and TA1535. These data indicate that the error-prone repair pathway can participate in mutagenesis induced by fluoroquinolones and also that the damage produced by these chemicals may be similar to that produced by nalidixic acid.
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Abstract
To study the regulation of the expression in Escherichia coli of the ubiG gene, which codes for the last enzyme in the pathway of ubiquinone biosynthesis, a fusion between the ubiG and lacZ genes was constructed in vitro. The results showed that (i) the expression of the ubiG gene was higher under aerobic conditions than under anaerobic growth conditions, (ii) the presence of glucose in the culture medium decreased the transcription of the ubiG gene, and (iii) cya and crp mutants exhibited lower levels of ubiG gene expression than the wild-type strain. The addition of cyclic AMP increased the expression of the ubiG gene in both cya and wild-type strains but not in a crp mutant. This fact suggests that the cyclic AMP receptor protein-cyclic AMP complex positively modulates ubiG gene transcription. It was also determined that the transcription of the ubiG gene was in the counterclockwise direction on the E. coli map.
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Llagostera M, Garrido S, Barbé J, Guerrero R, Rueff J. Influence of S9 mix in the induction of SOS system by quercetin. Mutat Res 1987; 191:1-4. [PMID: 3106804 DOI: 10.1016/0165-7992(87)90160-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The induction of recA, umuC and sfiA genes by quercetin was studied in the presence and in the absence of S9 mix. The inducing activity of quercetin is higher for sfiA than for recA and umuC genes in the absence of S9 mix. The putative genotoxic metabolites of quercetin produced by S9 mix display different inducing activities of the three SOS genes as compared to quercetin. The induction of sfiA gene is decreased by the presence of S9 mix, whereas an opposite effect was observed concerning umuC and recA. These data suggest that the error-prone repair pathway participates in mutagenesis by quercetin and its metabolites. Moreover, the type of DNA damage exerted by quercetin seems to be determined by its metabolic fate. The importance of testing for the induction of other SOS genes, together with sfiA, in the study of SOS functions as a genotoxic index is emphasized.
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81
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Barbé J, Gibert I, Llagostera M, Guerrero R. DNA repair systems in the phototrophic bacterium Rhodobacter capsulatus. JOURNAL OF GENERAL MICROBIOLOGY 1987; 133:961-6. [PMID: 3116168 DOI: 10.1099/00221287-133-4-961] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
UV irradiation and mitomycin C exposure trigger a protease-activity-dependent inhibition of cell division in Rhodobacter capsulatus, which begins about 2 h after the treatment is applied. UV irradiation also induces a dose-dependent mutagenesis with a maximal rate between 5 and 10 J m-2, with increased synthesis of a protein of Mr approximately 30,000 between 2 and 3 h after UV irradiation. In addition, R. capsulatus has an efficient photoreactivation system that reverses the lethal effects of UV irradiation in the presence of intense visible light.
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Barbé J, Castaño M, Llagostera M, Guerrero R. Isolation of the replication region of an indigenous plasmid ofRhodobacter sphaeroides. FEMS Microbiol Lett 1986. [DOI: 10.1111/j.1574-6968.1986.tb01762.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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83
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Llagostera M, Barbé J, Guerrero R. Characterization of SE1, a new general transducing phage of Salmonella typhimurium. JOURNAL OF GENERAL MICROBIOLOGY 1986; 132:1035-41. [PMID: 3531393 DOI: 10.1099/00221287-132-4-1035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A transducing phage, SE1, which is able to infect Salmonella typhimurium was isolated from a Salmonella enteritidis strain. SE1 is a temperate phage which is heteroimmune with respect to phages P22, L, KB1 and ES18. It is similar in morphology and size to phages P22, L and KB1 and is serologically related to phages P22 and L but not to KB1. Efficiencies of generalized transduction effected by phage SE1 are similar to those for P22HT (int7), a mutant which mediates a high frequency of chromosomal gene transduction. The lengths of chromosomal DNA transduced by SE1 and P22HT (int7) are similar. Furthermore, the SE1 prophage does not exclude the transducing particles from cells it has lysogenized; consequently it is possible to use both SE1 lysogens and non-lysogenic strains as recipients in SE1-mediated transduction experiments, and obtain similar transduction efficiencies. However, the SE1 prophage gives rise to a lysogenic conversion that decreases the rate of adsorption of SE1 and L phages by about 50%, but does not affect adsorption of P22. Altogether these results suggest that phage SE1 may be a useful tool in the genetic manipulation of S. typhimurium.
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84
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Llagostera M, Garrido S, Guerrero R, Barbé J. Induction of SOS genes of Escherichia coli by chromium compounds. ENVIRONMENTAL MUTAGENESIS 1986; 8:571-7. [PMID: 3525136 DOI: 10.1002/em.2860080408] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The induction of several SOS genes of Escherichia coli such as recA, umuC, and sfiA by hexavalent (K2Cr2O7, K2CrO4, and CrO3) and trivalent (CrCl3, Cr(NO3)3, and (CH3COO)3Cr) compounds of chromium was studied. Induction was measured as beta-galactosidase activity, using lacZ gene fusions under the control region of different SOS genes. The hexavalent chromium forms induced the genes responsible for massive synthesis of RecA protein, error-prone repair, and inhibition of cell division. On the other hand, the trivalent chromium compounds were unable to induce any of the SOS genes tested. Individual assay of hexavalent chromium compounds showed that K2Cr2O7 was a stronger inducing agent of those three SOS genes tested than K2CrO4, which, in turn, was stronger than CrO3. All this data led to the conclusion that hexavalent chromium compounds, but not trivalent, are proficient agents of induction of the SOS system and can produce indirect mutagenesis in Escherichia coli.
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Barbé J, Llagostera M, Villaverde A, Guerrero R. Expression of the SOS system in Escherichia coli growing under nitrate respiration conditions. Antonie Van Leeuwenhoek 1986; 52:63-74. [PMID: 2425733 DOI: 10.1007/bf00402688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Induction of several SOS functions by mitomycin C, bleomycin or thermal treatment of a recA441 mutant growing under nitrate respiration conditions was studied in Escherichia coli. Mitomycin C caused inhibition of cell division, induction of prophages and expression of umuC gene but like in aerobically growing cells, it did not trigger the cessation of cell respiration. On the contrary, both recA+ and recA441 cultures either treated with bleomycin or incubated at 42 degrees C failed to induce any of the different SOS functions cited above. Furthermore, after bleomycin addition or thermal treatment both recA+ and recA441 cultures did not present any variation in the cellular ATP level, contrary to what happens under aerobic growth. The blocking of the expression of some SOS functions under nitrate respiration conditions is not an irreversible process because cells incubated under these anaerobic conditions were able to induce the SOS system when changed to an aerobic medium 30 min after the SOS-inducing treatment had been applied.
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Barbé J, Vericat JA, Llagostera M, Guerrero R. Expression of the SOS genes of Escherichia coli in Salmonella typhimurium. MICROBIOLOGIA (MADRID, SPAIN) 1985; 1:77-87. [PMID: 2855830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
To lysogenize Salmonella typhimurium by Lambda phage, a region of 10.2 kb of Escherichia coli DNA carrying the nusA gene was cloned in a S. typhimurium strain containing a F'112 plasmid which codifies for the lamB region of E. coli. The strain of S. typhimurium obtained in this way, was lysogenized by lambda c IndO- bacteriophage harboring either a fusion between recA1 or sfiA genes of E. coli with lacZ gene. Likewise, pSE143 plasmid with a umu C::lacZ fusion was introduced in S. typhimurium. Afterwards, induction of these SOS genes was studied. Results obtained show that the basal transcription of both recA and sfiA genes of E. coli was higher in S. typhimurium than in E. coli. Nevertheless, induction of recA and sfiA genes by UV-irradiation and mitomycin C was higher in E. coli than in S. typhimurium. On the other hand, umuC gene of E. coli presents the same basal level of transcription in both E. coli and S. typhimurium species, although induction of this gene by UV-irradiation and mitomycin C was higher in S. typhimurium than in E. coli. Therefore, the plasmid pUA25 constructed in this work may be used to introduce, using the Lambda phage as a vector, the SOS genes of E. coli in other bacterial species which may be useful to study the relationship between their respective SOS systems.
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Llagostera M, Guerrero R, Villaverde A, Barbé J. Effect of adenine, cytidine and guanosine on the expression of the SOS system in Escherichia coli. JOURNAL OF GENERAL MICROBIOLOGY 1985; 131:113-8. [PMID: 3886832 DOI: 10.1099/00221287-131-1-113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Addition of cytidine or guanosine to UV-irradiated cells of a RecA+ strain of Escherichia coli did not produce any effect on the induction of two SOS functions: inhibition of cell division and expression of the umuC gene. Under the same conditions adenine gave a slight increase in the induction of these two responses. In a RecA441 mutant growing at 42 degrees C, both cytidine and guanosine inhibited these SOS functions, whereas adenine produced a large increase in their expression. Moreover, the ATP concentration of the RecA441 mutant at 42 degrees C showed a decrease which occurred earlier in the cells growing in the presence of cytidine or guanosine than in the absence of either compound. Adenine induced an increase of about three times the initial ATP concentration of this mutant at 42 degrees C which dropped quickly after 10 min. Neither cytidine nor guanosine increased the evolution of cellular ATP in UV-irradiated cells of the RecA+ strain, whereas adenine had only a slight positive effect. However, in UV-irradiated RecA+ cells with and without adenine, ATP levels dropped quickly to the initial value after 20 min. These data suggest that the influence of adenine, cytidine and guanosine on the expression of the RecA441 phenotype at 42 degrees C may be due to alteration of the cellular ATP concentration of this mutant.
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Guerrero R, Llagostera M, Villaverde A, Barbé J. Changes in ATP concentration in Escherichia coli during induction of the SOS system by mitomycin C and bleomycin. JOURNAL OF GENERAL MICROBIOLOGY 1984; 130:2247-51. [PMID: 6209361 DOI: 10.1099/00221287-130-9-2247] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Treatment of Escherichia coli with bleomycin induced a dramatic increase in ATP concentration in the first 30 min. Afterwards, in RecA+ strains, ATP dropped quickly to values similar to those of untreated cells. Mutants of E. coli defective in either RecA protein or RecA protease activity did not show this decrease, indicating that it was due to the action of RecA protease. The increase in ATP in the first 30 min was dependent on RecBC exonuclease activity and must have been due to substrate level phosphorylation, since an uncoupler such as dinitrophenol did not affect it. Nevertheless, mitomycin C did not induce any change in ATP pools of RecA+ strains, at least during 120 min following treatment. The implications of these findings are discussed in relation to the possible pathways of activation of RecA protease.
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Cadena A, Arso J, Vallès JM, Llagostera M, Vericat JA, Barbé J. [Evaluation of the possible mutagenicity of cyanamide using the Ames and Devoret tests]. BOLLETTINO CHIMICO FARMACEUTICO 1984; 123:74-82. [PMID: 6378217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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