Bernard Ollivier

University of Science and Technology Houari Boumediene, Le Retour de la Chasse, Alger, Algeria

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Publications (135)295.97 Total impact

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    ABSTRACT: The occurrence of magnetotactic bacteria (MTB) on a Tunisian marine coast exposed to heavy metals pollution (Sfax, Gulf of Gabès, Mediterranean Sea) was investigated. The MTB population of this Southern Mediterranean coast was compared to the MTB populations previously investigated on the French Northern Mediterranean coast. A dominant MTB coccus morphotype was observed by microscopy analysis. By pyrosequencing technology, the analysis of the 16S ribosomal RNA (rDNA) revealed as much as 33 operational taxonomic sequence units (OTUs) close to sequences of MTB accessible in the databases. The majority were close to MTB sequences of the "Med group" of α-Proteobacteria. Among them, a dominant OTU_001 (99 % of the MTB sequences) affiliated within the Magnetococcales order was highlighted. Investigating the capacities of this novel bacterium to be used in bioremediation and/or depollution processes could be envisaged.
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    ABSTRACT: A novel anaerobic, mesophilic, slightly halophilic sulfate-reducing bacterium designated strain Khaled BD4T was isolated from waters from a Tunisian thermal spring. The cells were vibrio-shaped or sigmoids (5-7 x 1-1.5 µm) and occurred singly or in pairs. Strain Khaled BD4T was Gram-staining-negative, motile, non-sporulated. It grew at temperature between 25 and 45°C (optimum 37 °C), at pH between 5.5 and 8.3 (optimum pH 7.0) and with NaCl between 0.5-8% (optimum 3%). It required vitamins or yeast extract for growth. Sulfate, thiosulfate, sulfite and elemental sulfur served as terminal electron acceptors, but not fumarate, nitrate or nitrite. Strain Khaled BD4T utilized H2 in the presence of 2 mM acetate (carbon source), but also lactate, formate, pyruvate and fumarate in the presence of sulfate. Lactate was incompletely oxidized to acetate. Amongst substrates used, only pyruvate was fermented. Desulfoviridin and c-type cytochrome were present. The G + C content of the DNA was 54.6 mol%. The main fatty acids were anteiso-C15:0, iso-C18:0, iso-C17:0 and iso-C14:0. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain Khaled BD4T had Desulfovibrio giganteus (96.7% similarity) as its closest phylogenetic relative. On the basis of the 16S rRNA gene sequence comparisons together with genetic and physiological characteristics, strain Khaled BD4T is proposed to be assigned to a new bacterial species, for which the name Desulfovibrio biadhensis is proposed. The type strain is Khaled BD4T (= DSM 28904T = JCM 30146T).
    International Journal of Systematic and Evolutionary Microbiology 01/2015; DOI:10.1099/ijs.0.000088 · 2.79 Impact Factor
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    Environmental Science and Pollution Research 01/2015; DOI:10.1007/s11356-015-4113-7 · 2.76 Impact Factor
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    ABSTRACT: Magnetotactic bacteria synthesize intracellular magnetite and/or greigite magnetosome crystals. They play a significant role in both iron and sulfur cycles in sedimentary aquatic environments. To get insight into the bio-geochemical contribution of MTB, more studies concerning their ecology and their distribution in diverse habitats are necessary. The MTB community of an oil-industry polluted area of the French Mediterranean coast has been previously investigated. Here, we investigate the MTB community from coastal sediments of a Mediterranean pristine area using optical and transmission electron microscopy and phylogenetic analysis based on 16S rRNA gene sequences. A particularly high diversity of MTB was observed, with cocci phylogenetically distributed across the order Magnetococcales, including a novel cluster with sequences from the Mediterranean Sea designated as “Med group”, and novel morphotypes.
    Current Microbiology 12/2014; DOI:10.1007/s00284-014-0745-y · 1.36 Impact Factor
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    ABSTRACT: A new anaerobic alkaliphilic H2-producer was isolated from a serpentinite-hosted ecosystem.•16S rDNA sequence analysis of strain PROH2 revealed its assignment to a novel Clostridium species.•The maximum H2 productions were obtained at 37 °C, initial pH 9.5 and 2 g/L of glucose.•The isolate is a good candidate for H2 production under alkaline conditions due to its high H2 yield.•It is the first anaerobic microorganism producing H2 at both high pH and low salinity.
    International Journal of Hydrogen Energy 11/2014; 39. DOI:10.1016/j.ijhydene.2014.09.111 · 2.93 Impact Factor
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    ABSTRACT: A new Gram-positive-staining, non-sporulating, mesophilic, amino acid-degrading anaerobic bacterium, designated strain OTA 102T (T = type strain), was isolated from an anaerobic sequencing batch reactor treating cooking tuna wastewater. The cells were curved rods (0.6-2.5 x 0.5 µm) and occurred singly or in pairs. The strain was motile by means of one lateral flagellum. Strain OTA 102T grew at temperatures between 30° and 45°C (optimum 40°C), pH between 6.0 and 8.4 (optimum 7.2), and NaCl between 1-5% (optimum 2%). Strain OTA 102T required yeast extract for growth. Serine, threonine, glycine, cysteine, citrate, fumarate, α-ketoglutarate and pyruvate were fermented. When cocultured with Methanobacterium formicicum as the hydrogen scavenger, strain OTA 102T oxidized alanine, valine, leucine, isoleucine, aspartate, tyrosine, histidine, methionine, histidine and asparagine. The genomic DNA G+C content of strain OTA 102T was 41.7 mol %. The main fatty acid was iso-C15:0 (58 %). Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain OTA 102T was related to Aminobacterium colombiense and Aminobacterium mobile (95.5 % and 95.2 % of similarity, respectively), phylum Synergistetes. On the basis of phylogenetic, genetic, and physiological characteristics, strain OTA 102T is proposed to be assigned to a new species of the genus Aminobacterium, A. thunnarium sp. nov.. The type strain is OTA 102T (=DSM 27500T= JCM 19320T). Copyright © 2014, the Society for General Microbiology.
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    ABSTRACT: A novel anaerobic, alkaliphilic, Gram-positive staining bacterium was isolated from a hydrothermal chimney in the Prony Bay, New Caledonia. This strain designated FatMR1(T) grew at temperatures from 20 to 55 °C (optimum 37 °C) and at pH between 7.5 and 10.5 (optimum 8.8-9). NaCl is not required for growth (optimum 0.2-0.5 %), but is tolerated up to 3 %. Sulfate, thiosulfate, elemental sulfur, sulfite, nitrate and nitrite are not used as terminal electron acceptors. Strain FatMR1(T) fermented pyruvate, yeast extract, peptone and biotrypcase and used fructose as the only sugar. The main fermentation products from fructose and proteinaceous compounds (e.g. peptone and biotrypcase) were acetate, H2 and CO2. Crotonate was disproportionated to acetate and butyrate. The predominant cellular fatty acids were C14:0 and C16:0. The G + C content of the genomic DNA was 37.1 mol %. On the basis of phylogenetic, genetic, and physiological properties, strain FatMR1(T) (=DSM 25890(T), =JCM 18390(T)) belonging to the phylum Firmicutes, class Clostridia, order Clostridiales, is proposed as a novel species of the genus Alkaliphilus, A. hydrothermalis sp. nov.
    Extremophiles 10/2014; DOI:10.1007/s00792-014-0697-y · 2.17 Impact Factor
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    ABSTRACT: Strain LTF Kr01, a novel mesophilic, anaerobic, halotolerant, rod-shaped bacterium was isolated from a drain at the bottom of a corroded kerosene storage tank of the Société Tunisienne des Industries de Raffinage (STIR), Bizerte, North Tunisia. Cells are Gram- positive rods, and occur singly or in pairs, motile by one lateral flagellum. Strain LTF Kr01 grows at temperatures between 15°C and 40°C (optimum 30°C), pH between 5.5 and 8.1 (optimum 7.2) and NaCl concentration between 0 and 50 g l-1 (optimum 5 g l-1). It reduces thiosulfate and elemental sulfur into sulfide, but not sulfate and or sulfite. It utilizes a large number wide range of carbohydrates (cellobiose, D-glucose, D-fructose, D-mannitol,D-ribose, D-sucrose, D-xylose, D-maltose, D-galactose, starch, and trehalose), and produces acetate, CO2, and H2, as end products from glucose fermentation. The DNA G+C content is 37.4 mol %. The predominant cellular fatty acids are C14:0 and C16:0. Phylogenetic analysis of the 16SrRNA gene sequence suggests that Fusibacter tunisiensis is its closest relative (identity of 94.6%). Based on phenotypic, phylogenetic and genotypic taxonomic characteristics, strain LTF Kr01T is proposed described as a novel species of the genus Fusibacter, order Clostridiales for which the name F. bizertensis sp. nov. is proposed. The type strain is LTF Kr01T (= DSM 28034 =JCM 19376).
    International Journal of Systematic and Evolutionary Microbiology 10/2014; 65(Pt 1). DOI:10.1099/ijs.0.066183-0 · 2.80 Impact Factor
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    ABSTRACT: RNA-seq was used to study the response of Desulfovibrio hydrothermalis, isolated from a deep-sea hydrothermal chimney on the East-Pacific Rise at a depth of 2,600 m, to various hydrostatic pressure growth conditions. The transcriptomic datasets obtained after growth at 26, 10 and 0.1 MPa identified only 65 differentially expressed genes that were distributed among four main categories: aromatic amino acid and glutamate metabolisms, energy metabolism, signal transduction, and unknown function. The gene expression patterns suggest that D. hydrothermalis uses at least three different adaptation mechanisms, according to a hydrostatic pressure threshold (HPt) that was estimated to be above 10 MPa. Both glutamate and energy metabolism were found to play crucial roles in these mechanisms. Quantitation of the glutamate levels in cells revealed its accumulation at high hydrostatic pressure, suggesting its role as a piezolyte. ATP measurements showed that the energy metabolism of this bacterium is optimized for deep-sea life conditions. This study provides new insights into the molecular mechanisms linked to hydrostatic pressure adaptation in sulfate-reducing bacteria.
    PLoS ONE 09/2014; 9(9):e106831. DOI:10.1371/journal.pone.0106831 · 3.53 Impact Factor
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    ABSTRACT: To date, xylanases have expanded their use in many processing industries, such as pulp, paper, food, and textile. This study aimed the production and partial characterization of a thermostable xylanase from a novel thermophilic anaerobic bacterium Caldicoprobacter algeriensis strain TH7C1(T) isolated from a northeast hot spring in Algeria. The obtained results showed that C. algeriensis xylanase seems not to be correlated with the biomass growth profile whereas the maximum enzyme production (140.0 U/ml) was recorded in stationary phase (18 h). The temperature and pH for optimal activities were 70 °C and 11.0, respectively. The enzyme was found to be stable at 50, 60, 70, and 80 °C, with a half-life of 10, 9, 8, and 4 h, respectively. Influence of metal ions on enzyme activity revealed that Ca(+2) enhances greatly the relative activity to 151.3 %; whereas Hg(2+) inhibited significantly the enzyme. At the best of our knowledge, this is the first report on the production of xylanase by the thermophilic bacterium C. algeriensis. This thermo- and alkaline-tolerant xylanase could be used in pulp bleaching process.
    Applied biochemistry and biotechnology 08/2014; DOI:10.1007/s12010-014-1153-2 · 1.94 Impact Factor
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    ABSTRACT: The shallow submarine hydrothermal field of the Prony Bay (New Caledonia) discharges hydrogen- and methane-rich fluids with low salinity, temperature (<40°C) and high pH (11) produced by the serpentinization reactions of the ultramafic basement into the lagoon seawater. They are responsible for the formation of carbonate chimneys at the lagoon seafloor. CE-SSCP fingerprinting, quantitative PCR and sequence analysis of 16S rRNA genes revealed changes in microbial community structure, abundance and diversity depending on the location, water depth and structure of the carbonate chimneys. The low archaeal diversity was dominated by few uncultured Methanosarcinales similar to those found in other serpentinization-driven submarine and subterrestrial ecosystems (e.g. Lost City, The Cedars). The most abundant and diverse bacterial communities were mainly composed of Chloroflexi, Deinococcus-Thermus, Firmicutes, and Proteobacteria. Functional gene analysis revealed similar abundance and diversity of both Methanosarcinales methanoarchaea and Desulfovibrionales- and Desulfobacterales sulfate-reducers in the studied sites. Molecular studies suggest that redox reactions involving hydrogen, methane and sulfur compounds (e.g. sulfate) are the energy driving forces of the microbial communities inhabiting the Prony hydrothermal system.
    Environmental Microbiology Reports 06/2014; 6(6). DOI:10.1111/1758-2229.12184 · 3.26 Impact Factor
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    ABSTRACT: The thermophilic sulfate-reducing archaeon Archaeoglobus fulgidus strain VC-16 (DSM 4304), which is known to oxidize fatty acids and n-alkenes, was shown to oxidize saturated hydrocarbons (n-alkanes in the range C10-C21) with thiosulfate or sulfate as a terminal electron acceptor. The amount of n-hexadecane degradation observed was in stoichiometric agreement with the theoretically expected amount of thiosulfate reduction. One of the pathways used by anaerobic microorganisms to activate alkanes is addition to fumarate that involves alkylsuccinate synthase as a key enzyme. A search for genes encoding homologous enzymes in A. fulgidus identified the pflD gene (locus-tag AF1449) that was previously annotated as a pyruvate formate lyase. A phylogenetic analysis revealed that this gene is of bacterial origin and was likely acquired by A. fulgidus from a bacterial donor through a horizontal gene transfer. Based on three-dimensional modeling of the corresponding protein and molecular dynamic simulations, we hypothesize an alkylsuccinate synthase activity for this gene product. The pflD gene expression was upregulated during the growth of A. fulgidus on an n-alkane (C16) compared with growth on a fatty acid. Our results suggest that anaerobic alkane degradation in A. fulgidus may involve the gene pflD in alkane activation through addition to fumarate. These findings highlight the possible importance of hydrocarbon oxidation at high temperatures by A. fulgidus in hydrothermal vents and the deep biosphere.The ISME Journal advance online publication, 24 April 2014; doi:10.1038/ismej.2014.58.
    The ISME Journal 04/2014; 8(11). DOI:10.1038/ismej.2014.58 · 9.27 Impact Factor
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    ABSTRACT: Members of the deep-branching order Thermotogales are widespread in various terrestrial, submarine and subterrestrial extreme environments. This bacterial order included both thermophilic and hyperthermophilic anaerobic microorganisms so far pertaining to ten genera. It is only recently (2011) that cultivation of a mesophilic member of this order belonging to a novel genus, Mesotoga, has been successful. All members, with the exception of Mesotoga spp., are recognized as high hydrogen producers having possible applications in biotechnology with a peculiar emphasis for members of the genus Thermotoga (e.g. T. maritima and T. neapolitana). The ecology, phylogeny and metabolism linked to hydrogen production of these bacteria, are reviewed.
    Microbial BioEnergy: Hydrogen Production, Edited by Zannoni D, De Philippis R, 03/2014: chapter Members of the Order Thermotogales: From Microbiology to Hydrogen Production: pages 199; Springer., ISBN: 978-94-017-8553-2
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    ABSTRACT: A novel thermotolerant, anaerobic, Gram-positive staining, spore-forming bacterium was isolated from a hydrothermal chimney in the Prony Bay, New Caledonia. This strain designated FatNI3T grew at temperatures from15 to 55 °C (optimum 30°C) and at pH between 5.8 and 8.9 (optimum 7.7). It is slightly halophilic requiring at least 0.5% NaCl for growth (optimum 2.5-3.0%), and supporting it up to 6 %. Sulfate, thiosulfate, elemental sulfur, sulfite, nitrate and nitrite were not used as terminal electron acceptors. Growth of strain FatNI3T was inhibited in the presence of sulfite (2 mM) or nitrite (2 mM). Strain FatNI3T fermented cellobiose, glucose, mannose, maltose, sucrose, galactose, lactose, ribose, fructose, rhamnose, raffinose, xylose, yeast extract, peptone and biotrypcase. The main fermentation products from glucose metabolism were acetate, ethanol, H2 and CO2. The predominant cellular fatty acids were iso-C15:0, anteiso-C15:0. The main polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, glycolipids and phospholipids. The G+C content of the genomic DNA was 36.6 mol%. On the basis of phylogenetic and physiological properties, strain FatNI3T (= DSM 25904 = JCM 18391) belonging to the phylum Firmicutes, class Clostridia, order Clostridiales, is proposed as a novel species of the genus Vallitalea, V. pronyensis sp. nov..
    International Journal of Systematic and Evolutionary Microbiology 01/2014; DOI:10.1099/ijs.0.055756-0 · 2.79 Impact Factor
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    ABSTRACT: This work aims to study the by-products generated by the anaerobic degradation process of synthetic wastewater containing indigo dye. These by-products were analysed and identified by both high performance liquid chromatography (HPLC) and nuclear magnetic resonance (1H NMR). HPLC results showed the dependence of the by-products to the operating conditions. The obtained HPLC chromatogram at the end of the experiments (Run 1) reveals different fractions, with at least eight distinguishable by-products. Increasing the hydraulic retention time from 1 to 5 days (Run 5) which corresponding to the start up of the bioreactor caused a significant change of the obtained HPLC chromatogram, with the decrease of the number of these by-products to only 3 ones. 1H NMR analysis was realised with three representative fractions. The results showed that hypothetical structure of the by-products corresponding to aromatic cycles 1,2-disubstituted and possessing an axial symmetry similar to the phthalate groups.
    Desalination and water treatment 12/2013; 53(7):1-9. DOI:10.1080/19443994.2013.870744 · 0.99 Impact Factor
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    ABSTRACT: Gram-positive spore-forming sulfate reducers and particularly members of the genus Desulfotomaculum are commonly found in the subsurface biosphere by culture based and molecular approaches. Due to their metabolic versatility and their ability to persist as endospores. Desulfotomaculum spp. are well-adapted for colonizing environments through a slow sedimentation process. Because of their ability to grow autotrophically (H2/CO2) and produce sulfide or acetate, these microorganisms may play key roles in deep lithoautotrophic microbial communities. Available data about Desulfotomaculum spp. and related species from studies carried out from deep freshwater lakes, marine sediments, oligotrophic and organic rich deep geological settings are discussed in this review.
    Frontiers in Microbiology 12/2013; 4:362. DOI:10.3389/fmicb.2013.00362 · 3.94 Impact Factor
    This article is viewable in ResearchGate's enriched format
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    ABSTRACT: Human African trypanosomiasis (HAT) is caused by trypanosomes transmitted to humans by the tsetse fly, in which they accomplish their development into their infective metacyclic form. The crucial step in parasite survival occurs when it invades the fly midgut. Insect digestive enzymes and immune defenses may be involved in the modulation of the fly's vector competence, together with bacteria that could be present in the fly's midgut. In fact, in addition to the three bacterial symbionts that have previously been characterized, tsetse flies may harbor additional bacterial inhabitants. This review focuses on the diversity of the bacterial flora in Glossina, with regards to the fly species and their geographical distribution. The rationale was (i) that these newly identified bacteria, associated with tsetse flies, may contribute to vector competence as was shown in other insects and (ii) that differences may exist according to fly species and geographic area. A more complete knowledge of the bacterial microbiota of the tsetse fly and the role these bacteria play in tsetse biology may lead to novel ways of investigation in view of developing alternative anti-vector strategies for fighting human-and possibly animal-trypanosomiasis.
    Frontiers in Cellular and Infection Microbiology 07/2013; 3:34. DOI:10.3389/fcimb.2013.00034 · 2.62 Impact Factor
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    ABSTRACT: A novel anaerobic, chemo-organotrophic sulfate-reducing bacterium, designated strain Olac 40T, was isolated from a Tunisian wastewater digestor. Cells were curved motile rods or vibrios (5.0-7.0 x 0.5 μm). Strain Olac 40T grew at temperatures between 15 and 50°C (optimum 40°C), and at pH between 5.0 and 9.0 (optimum 7.1). It did not require NaCl for growth but tolerated it up to 50 g l-1 (optimum 2 g l-1). In the presence of sulfate or thiosulfate, strain Olac 40T used lactate, pyruvate and formate as energy sources. Growth was observed on H2 only in the presence of acetate as carbon source. In the presence of sulfate or thiosulfate, the end-products of lactate oxidation were acetate, sulfide and CO2. Sulfate, thiosulfate and sulfite were used as terminal electron acceptors, but not elemental sulfur, nitrate and nitrite. The genomic DNA G+C content of strain Olac 40T was 70 mol %. Profile of polar lipids consisted of phosphatidylglycerol, phosphatidylethanolamine, aminophospholipid and four phospholipids The main fatty acids were C16: 0, anteiso-C15: 0 and iso-C15: 0. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain Olac 40T was affiliated with the family Desulfovibrionaceae within the class Deltaproteobacteria. On the basis of the 16S rRNA gene sequence comparisons and physiological characteristics, strain Olac 40T is proposed to be assigned to a new species of the genus Desulfocurvus, for which the name Desulfocurvus thunnarius is proposed. The type strain is Olac 40T (=DSM 26129T= JCM 18546T).
    International Journal of Systematic and Evolutionary Microbiology 06/2013; DOI:10.1099/ijs.0.051664-0 · 2.79 Impact Factor
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    ABSTRACT: An anaerobic thermophilic bacterium designated CA9F1 was isolated from a thermal spring in France. Strain CA9F1 was observed to grow at temperatures between 55 and 70 °C (optimum 65 °C) and at pH between 6.8 and 9.5 (optimum pH 7.4). Strain CA9F1 does not require salt for growth (0-10 g l(-1) NaCl), with an optimum at 1 g l(-1). The DNA G+C content was determined to be 38.5 mol% (Tm). The major cellular fatty acids identified were C15:0, C16:0, C17:0 iso. Based on phenotypic, chemotaxonomic and genotypic properties, strain CA9F1 was identified as Thermovenabulum gondwanense and this species was studied in more detail. Strain CA9F1 is a Gram-positive bacterium which forms a complex and regular multilayered cell wall structure, here characterised as being due to the presence of an S-layer. The network covers the entire cell surface and forms a hexagonal structure resembling that observed for Deinococcus radiodurans. The main protein component of the S-layer possesses domains comparable to that of the S-layer protein of Halothermothrix orenii. The characteristics of the strain were compared to that of T. gondwanese R270(T) isolated from microbial mats thriving in the thermal waters of a Great Artesian Basin bore runoff channel at 66 °C, in Australia. Significant differences were observed between CA9F1 and the type strain. One of the major physiological differences is the inability of CA9F1 to reduce Fe(III). An emended description of T. gondwanense is given.
    Antonie van Leeuwenhoek 06/2013; DOI:10.1007/s10482-013-9947-8 · 2.07 Impact Factor

Publication Stats

2k Citations
295.97 Total Impact Points

Institutions

  • 2014
    • University of Science and Technology Houari Boumediene
      Le Retour de la Chasse, Alger, Algeria
  • 1986–2014
    • Aix-Marseille Université
      • Laboratoire de Chimie Bactérienne (UMR 7283 LCB)
      Marsiglia, Provence-Alpes-Côte d'Azur, France
    • University of California, Los Angeles
      • School of Public Health
      Los Ángeles, California, United States
  • 2002–2013
    • Institute of Research for Development
      Marsiglia, Provence-Alpes-Côte d'Azur, France
  • 2010
    • l' Institut National des Sciences Appliquées et de Technologie (Tunisienne)
      Tunis-Ville, Tūnis, Tunisia
  • 1993–1995
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France