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Abstract
The size of tsetse flies is often associated with population dynamics and vectorial capacity parameters. Adult fly size is generally estimated from measurements of wing segments. To take measure of the wing, a semi-automatic software was developed by CIRAD-EMVT and IRD. It was used in wild populations of Glossina tachinoides Westwood and G. palpalis gambiensis Vanderplank (Diptera: Glossinidae) trapped near Bobo-Dioulasso, Burkina Faso. From an numeric picture of the wing, the software calculates the length of vein segments, the ratios between these lengths, the surface of the tsetse characteristic "hatchet cell", and the greyness on the wings. The data were interesting at the level of taxonomy. In addition, they help specify physiological characteristics of the studied populations.
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Affiliation(s)
- S de La Rocque
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Département Elevage et Médecine Vétérinaire (CIRAD-EMVT), Campus de Baillarguet, BP 5035, 34032 Montpellier, France.
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2
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Abstract
Radiological characterisation of an experimental chamber and other areas of an ultra-high intensity laser facility (-terawatt) revealed significant levels of X ray, gamma and neutron radiation. Different techniques were used to detect and measure this radiation: TLD. photographic film, bubble detectors and germanium spectrometry. A test series of radiological measurements was made for 150 laser shots (300 femtoseconds) with energies in the 1 to 20 J range and a target illuminance of 10(19) W.cm2. Gamma dose equivalents in the vicinity of the chamber varied between 0.7 and 73 mSv. The dose equivalent due to the neutron component was evaluated to be 1% of the gamma dose equivalent. The amount of radiation generated depends on the laser energy and the nature of the target. No activation or contamination of the chamber or target holder were observed. Ultra-high intensity lasers are being extensively developed at the present time and the investigations performed demonstrate that it is necessary to take radiological risks into consideration in the design of ultra-high intensity laser facilities and to define personnel access conditions.
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Affiliation(s)
- F Borne
- CEA DAM-Ile-de-France, Service de Protection contre les Rayonnements, Bruyères-le-Châtel.
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3
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Rébora K, Desmoucelles C, Borne F, Pinson B, Daignan-Fornier B. Yeast AMP pathway genes respond to adenine through regulated synthesis of a metabolic intermediate. Mol Cell Biol 2001; 21:7901-12. [PMID: 11689683 PMCID: PMC99957 DOI: 10.1128/mcb.21.23.7901-7912.2001] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Saccharomyces cerevisiae, AMP biosynthesis genes (ADE genes) are transcriptionally activated in the absence of extracellular purines by the Bas1p and Bas2p (Pho2p) transcription factors. We now show that expression of the ADE genes is low in mutant strains affected in the first seven steps of the pathway, while it is constitutively derepressed in mutant strains affected in later steps. Combined with epistasy studies, these results show that 5'-phosphoribosyl-4-succinocarboxamide-5-aminoimidazole (SAICAR), an intermediate metabolite of the pathway, is needed for optimal activation of the ADE genes. Two-hybrid studies establish that SAICAR is required to promote interaction between Bas1p and Bas2p in vivo, while in vitro experiments suggest that the effect of SAICAR on Bas1p-Bas2p interaction could be indirect. Importantly, feedback inhibition by ATP of Ade4p, catalyzing the first step of the pathway, appears to regulate SAICAR synthesis in response to adenine availability. Consistently, both ADE4 dominant mutations and overexpression of wild-type ADE4 lead to deregulation of ADE gene expression. We conclude that efficient transcription of yeast AMP biosynthesis genes requires interaction between Bas1p and Bas2p which is promoted in the presence of a metabolic intermediate whose synthesis is controlled by feedback inhibition of Ade4p acting as the purine nucleotide sensor within the cell.
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Affiliation(s)
- K Rébora
- Institut de Biochimie et Génétique Cellulaires, CNRS UMR 5095, 33077 Bordeaux Cedex, France
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4
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Liu Z, Guiliani N, Appia-Ayme C, Borne F, Ratouchniak J, Bonnefoy V. Construction and characterization of a recA mutant of Thiobacillus ferrooxidans by marker exchange mutagenesis. J Bacteriol 2000; 182:2269-76. [PMID: 10735871 PMCID: PMC111277 DOI: 10.1128/jb.182.8.2269-2276.2000] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To construct Thiobacillus ferrooxidans mutants by marker exchange mutagenesis, a genetic transfer system is required. The transfer of broad-host-range plasmids belonging to the incompatibility groups IncQ (pKT240 and pJRD215), IncP (pJB3Km1), and IncW (pUFR034) from Escherichia coli to two private T. ferrooxidans strains (BRGM1 and Tf-49) and to two collection strains (ATCC 33020 and ATCC 19859) by conjugation was analyzed. To knock out the T. ferrooxidans recA gene, a mobilizable suicide plasmid carrying the ATCC 33020 recA gene disrupted by a kanamycin resistance gene was transferred from E. coli to T. ferrooxidans ATCC 33020 by conjugation under the best conditions determined. The two kanamycin-resistant clones, which have retained the kanamycin-resistant phenotype after growth for several generations in nonselective medium, were shown to have the kanamycin resistance gene inserted within the recA gene, indicating that the recA::Omega-Km mutated allele was transferred from the suicide plasmid to the chromosome by homologous recombination. These mutants exhibited a slightly reduced growth rate and an increased sensitivity to UV and gamma irradiation compared to the wild-type strain. However, the T. ferrooxidans recA mutants are less sensitive to these physical DNA-damaging agents than the recA mutants described in other bacterial species, suggesting that RecA plays a minor role in DNA repair in T. ferrooxidans.
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Affiliation(s)
- Z Liu
- Laboratoire de Chimie Bactérienne, Institut de Biologie Structurale et de Microbiologie, C.N.R.S., 13402 Marseille Cedex 20, France
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Pinson B, Sagot I, Borne F, Gabrielsen OS, Daignan-Fornier B. Mutations in the yeast Myb-like protein Bas1p resulting in discrimination between promoters in vivo but notin vitro. Nucleic Acids Res 1998; 26:3977-85. [PMID: 9705508 PMCID: PMC147816 DOI: 10.1093/nar/26.17.3977] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Bas1p is a yeast transcription factor that activates expression of purine and histidine biosynthesis genes in response to extracellular purine limitation. The N-terminal part of Bas1p contains an Myb-like DNA binding domain composed of three tryptophan-rich imperfect repeats. We show that mutating the conserved tryptophan residues in the DNA binding domain of Bas1p severely impairs in vivo activation of target genes and in vitro DNA binding of Bas1p. We also found that two mutations (H34L and W42A) in the first repeat make Bas1p discriminate between promoters in vivo . These two BAS1 mutants are able to activate expression of an HIS4-lacZ fusion but not that of ADE1-lacZ or ADE17-lacZ fusions. Surprisingly, these mutant proteins bind equally well to the three promoters in vitro , suggesting that the mutations affect the interaction of Bas1p with some promoter-specific factor(s) in vivo . By mutating a potential nucleotide binding site in the DNA binding domain of Bas1p, we also show that this motif does not play a major role in purine regulation of Bas1p activity. Finally, using a green fluorescence protein (GFP)-Bas1p fusion, we establish the strict nuclear localization of Bas1p and show that it is not affected by extracellular adenine.
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Affiliation(s)
- B Pinson
- Institut de Biochimie et Génétique Cellulaires, CNRS UPR9026, 1 rue Camille Saint-Saëns, F-33077 Bordeaux Cedex, France
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Foglino M, Borne F, Bally M, Ball G, Patte JC. A direct sulfhydrylation pathway is used for methionine biosynthesis in Pseudomonas aeruginosa. Microbiology (Reading) 1995; 141 ( Pt 2):431-9. [PMID: 7704274 DOI: 10.1099/13500872-141-2-431] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The relationship between genes and enzymes in the methionine biosynthetic pathway has been studied in Pseudomonas aeruginosa. The first step is catalysed by an O-succinylhomoserine synthase, the product of the metA gene mapped at 20 min on the chromosome. The second step is achieved by direct sulfhydrylation, involving the enzyme encoded by a metZ gene that we have identified and sequenced, located at 40 min. Thus Pseudomonas appears to be the only organism so far described that uses O-succinylhomoserine as substrate for a direct sulfhydrylation. As in yeast, the two transsulfuration pathways between cysteine and homocysteine, with cystathionine as an intermediate, probably exist in parallel in this organism.
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Affiliation(s)
- M Foglino
- Laboratoire de Chimie Bactérienne, Centre National de la Recherche Scientifique, Marseille, France
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7
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Abstract
Three genes from Pseudomonas aeruginosa involved in threonine biosynthesis, hom, thrB and thrC, encoding homoserine dehydrogenase (HDH), homoserine kinase (HK) and threonine synthase (TS), respectively, have been cloned and sequenced. The hom and thrc genes lie at the thr locus of the P. aeruginosa chromosome map (31 min) and are likely to be organized in a bicistronic operon. The encoded proteins are quite similar to the Hom and TS proteins from other bacterial species. The thrB gene was located by pulsed-field gel electrophoresis experiments at 10 min on the chromosome map. The product of this gene does not share any similarity with other known ThrB proteins. No phenotype could be detected when the chromosomal thrB gene was inactivated by an insertion. Therefore the existence of isozymes for this activity is postulated. HDH activity was feedback inhibited by threonine; the expression of all three genes was constitutive. The overall organization of these three genes appears to differ from that in other bacterial species.
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Affiliation(s)
- C Clepet
- Laboratoire de Chimie Bactérienne, Centre National de la Recherche Scientifique, Marseille, France
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8
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Martin C, Cami B, Borne F, Jeenes DJ, Haas D, Patte JC. Heterologous expression and regulation of the lysA genes of Pseudomonas aeruginosa and Escherichia coli. Mol Gen Genet 1986; 203:430-4. [PMID: 3018430 DOI: 10.1007/bf00422067] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The Pseudomonas aeruginosa lysA gene encoding diaminopimelate decarboxylase (DAP-decarboxylase) was cloned into a broad host range vector. This gene complemented a lys mutation at the lys-12 locus of P. aeruginosa and a lysA defect in Escherichia coli. The P. aeruginosa DAP-decarboxylase was synthesized constitutively in P. aeruginosa as well as in E. coli, where the Pseudomonas lysA gene was poorly expressed. By contrast, the E. coli lysA gene was expressed well in P. aeruginosa and subject to lysine regulation when the E. coli LysR activator protein was provided. This indicates that the mechanism of transcriptional activation for the E. coli lysA gene is effective in the heterologous host.
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Stragier P, Borne F, Richaud F, Richaud C, Patte JC. Regulatory pattern of the Escherichia coli lysA gene: expression of chromosomal lysA-lacZ fusions. J Bacteriol 1983; 156:1198-203. [PMID: 6417111 PMCID: PMC217968 DOI: 10.1128/jb.156.3.1198-1203.1983] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The regulation of lysA which encodes the last enzyme for lysine biosynthesis in Escherichia coli, diaminopimelic acid-decarboxylase, was studied by using lysA-lacZ fusions. Our results indicate an absolute requirement for the LysR product for its activation, LysR protein present in a limiting amount which can be titrated by a multicopy plasmid carrying its target site and a negative regulatory role for the LysA protein itself which decreases lysA-lacZ expression 30-fold.
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Stragier P, Richaud F, Borne F, Patte JC. Regulation of diaminopimelate decarboxylase synthesis in Escherichia coli. I. Identification of a lysR gene encoding an activator of the lysA gene. J Mol Biol 1983; 168:307-20. [PMID: 6411928 DOI: 10.1016/s0022-2836(83)80020-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The synthesis of diaminopimelate decarboxylase, which catalyzes the decarboxylation of diaminopimelate into lysine, is known to be repressed by lysine and induced by diaminopimelate in Escherichia coli K12. Until now only mutations in lysA, the structural gene for diaminopimelate decarboxylase, have been described that lead to a Lys- phenotype. A set of plasmids carrying adjacent inserts of the lysA region was constructed and employed to transform different Lys- mutants. The complementation pattern observed and the corresponding expression of the lysA gene show that in fact the Lys- phenotype can be obtained by mutations in two different and closely linked loci: one being the lysA structural gene, and the other called lysR. We propose that the lysR gene encodes a positive effector required for the full expression of the lysA gene. The synthesis of a hybrid lysA-lacZ protein constructed in vitro was observed to be decreased dramatically in lysR mutants. Moreover, all the regulatory features were lost, indicating that the LysR activator is necessary for the regulation of lysA expression. The gene order is thyA lysA lysR clockwise around 61 minutes on the chromosome, lysA being transcribed counter-clockwise.
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Patte JC, Morand P, Boy E, Richaud C, Borne F. The relA locus and the regulation of lysine biosynthesis in Escherichia coli. Mol Gen Genet 1980; 179:319-25. [PMID: 6110161 DOI: 10.1007/bf00425459] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The allelic state of relA influences the phenotype of Escherichia coli strains carrying the lysA22 mutation:lysA22 relA strains are Lys- where lysA22 relA+ strains grow (slowly) in the absence of lysine. This physiological effect has been related to an effect of the expression of the relA locus on the regulation of lysine biosynthesis. The fully derepressed levels of some lysine enzymes (aspartokinase III, aspartic semialdehyde dehydrogenase, didhydrodipicolinate reductase) are observed under lysine limitation only in rel+ strains. And the induction of DAP-decarboxylase by DAP is much higher in rel+ than in rel- strains when an amino acid limitation of growth is also realised. These results are in agreement with the hypothesis of Stephens et al. (1975) on a possible role of the stringent regulation as a general signal for amino acid deficiency.
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12
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Abstract
We devised a procedure in order to isolate, in Escherichia coli, constitutive mutants for aspartokinase III synthesis, the first enzyme of the lysine regulon. It consists of the introduction of a limiting step in lysine biosynthesis, by the use of the partial suppression of a nonsense mutation. For the first time we could isolate many constitutive mutants. Their characteristics (cotransduction with the lysC structural gene; no effect on the synthesis of other enzymes of the regulon; cis-dominance) lead to classify these mutations as operator-type. The fact that no repressor mutations could be isolated is discussed.
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Boy E, Borne F, Patte JC. Effect of mutations affecting lysyl-tRNAlys on the regulation of lysine biosynthesis in Escherichia coli. Mol Gen Genet 1978; 159:33-8. [PMID: 345082 DOI: 10.1007/bf00401745] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
When studying mutants affecting lysyl-tRNA synthetase or tRNAlys (hisT, hisW), a lack of correlation is clearly observed between the amount of lysyl-tRNA and the level of derepression of several lysine biosynthetic enzymes. This exlcudes the possible role of lysyl-tRNA as the specific corepressor of the lysine regulon. However, the level of derepression of DAP-decarboxylase, the last enzyme of the lysine pathway, is very low in the hisT mutant; this indicates that tRNAlys is a secondary effector involved in the regulation of the synthesis of this enzyme.
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Cassan M, Boy E, Borne F, Patte JC. Regulation of the lysine biosynthetic pathway in Escherichia coli K-12: isolation of a cis-dominant constitutive mutant for AK III synthesis. J Bacteriol 1975; 123:391-9. [PMID: 238953 PMCID: PMC235741 DOI: 10.1128/jb.123.2.391-399.1975] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A method for isolating regulatory mutants for the synthesis of lysine biosynthetic enzymes in Escherichia coli is described. One of them is identified as a cis-dominant constitutive mutant for the synthesis of the lysine-sensitive asportokinase AK III (lysC gene).
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Patte JC, Boy E, Borne F. Role of the lysine-sensitive aspartokinase 3 in the regulation of DAP-decarboxylase synthesis in Escherichia coli K 12. FEBS Lett 1974; 43:67-70. [PMID: 4153049 DOI: 10.1016/0014-5793(74)81107-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Thèze J, Margarita D, Cohen GN, Borne F, Patte JC. Mapping of the structural genes of the three aspartokinases and of the two homoserine dehydrogenases of Escherichia coli K-12. J Bacteriol 1974; 117:133-43. [PMID: 4148765 PMCID: PMC246534 DOI: 10.1128/jb.117.1.133-143.1974] [Citation(s) in RCA: 85] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Mutants requiring threonine plus methionine (or homoserine), or threonine plus methionine plus diaminopimelate (or homoserine plus diaminopimelate) have been isolated from strains possessing only one of the three isofunctional aspartokinases. They have been classified in several groups according to their enzymatic defects. Their mapping is described. Several regions of the chromosome are concerned: thrA (aspartokinase I-homoserine dehydrogenase I) is mapped in the same region as thrB and thrC (0 min). lysC (aspartokinase III) is mapped at 80 min, far from the other genes coding for diaminopimelate synthesis. metLM (aspartokinase II-homoserine dehydrogenase II) lies at 78 min closely linked to metB, metJ, and metF.
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Patte JC, Zuber M, Borne F. Regulation of the synthesis of aspartokinase 3 of Escherichia coli by amino acids other than lysine. Mol Gen Genet 1972; 116:35-9. [PMID: 4558446 DOI: 10.1007/bf00334257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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