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Jeanclaude Piffaretti - One of the best experts on this subject based on the ideXlab platform.

  • analysis of the genetic polymorphism of borrelia burgdorferi sensu lato by multilocus Enzyme Electrophoresis
    International Journal of Systematic and Evolutionary Microbiology, 1996
    Co-Authors: Tiziano Balmelli, Jeanclaude Piffaretti
    Abstract:

    In recent years, Borrelia burgdorferi sensu lato has been subdivided into three species, Borrelia burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii, and a new species restricted to Japan, Borrelia japonica, has been isolated from Ixodes ovatus. In addition, members of several new genomic groups have been found in America and in Europe, suggesting that there are additional genospecies. In order to study the diversity of B. burgdorferi sensu lato, we analyzed 54 isolates cultured from humans and from different tick species and obtained from diverse geographic areas, including Europe, the United States, Japan, and the People's Republic of China. In order to investigate the genetic relationship between microorganisms that are transmitted by soft ticks and microorganisms that cause Lyme disease, we also included three strains of relapsing fever spirochetes. The method which we used was multilocus Enzyme Electrophoresis; 12 genetic loci were characterized on the basis of the electrophoretic mobilities of their products, and 50 distinct allele profiles (electrophoretic types) were distinguished. The mean genetic diversity per locus was 0.747. A cluster analysis of a matrix of genetic distances for pairs of electrophoretic types revealed 11 divisions that were separated at genetic distances greater than 0.65. Five of these divisions corresponded to B. burgdorferi sensu stricto. B. garinii, B. afzelii, B. japonica, and the newly proposed species “Borrelia andersonii”. Our results also confirmed that there are two additional genomic groups in Europe and at least one additional group in the United States. The relapsing fever spirochetes were not clearly separated from the spirochetes associated with Lyme disease. In conclusion, we believe that the previously proposed subdivision of B. burgdorferi sensu lato into only four species should be reconsidered.

  • population genetic analysis of borrelia burgdorferi isolates by multilocus Enzyme Electrophoresis
    Infection and Immunity, 1992
    Co-Authors: Patrick Boerlin, Guy Baranton, O Peter, Annegabrielle Bretz, Daniele Postic, Jeanclaude Piffaretti
    Abstract:

    Fifty Borellia burgdorferi strains isolated from humans and ticks in Europe and the United States were analyzed by multilocus Enzyme Electrophoresis. Eleven genetic loci were characterized on the basis of the electrophoretic mobilities of their products. Ten loci were polymorphic. The average number of alleles per locus was 5.9, with a mean genetic diversity of 0.673 among electrophoretic types (ETs). The strains were grouped into 35 ETs constituting three main divisions (I, II, and III) separated at a genetic distance greater than 0.75. Divisions I, II, and III contained 13, 6, and 16 ETs, respectively. These findings, together with previous data from DNA hybridization and restriction Enzyme analysis of rRNA genes, suggest that divisions I, II, and III may represent three distinct genomic species. All three divisions contained human clinical ETs. However, in division I, which includes the ET of the type strain of B. burgdorferi, the human pathogenic ETs constituted a single clone. The ETs of division I were from west-central Europe and the United States, whereas divisions II and III contained ETs from west-central and northern Europe but not from the United States. Finally, our data show that the genetic structure of B. burgdorferi populations is clonal.

  • taxonomy of the genus listeria by using multilocus Enzyme Electrophoresis
    International Journal of Systematic and Evolutionary Microbiology, 1991
    Co-Authors: Patrick Boerlin, J Rocourt, Jeanclaude Piffaretti
    Abstract:

    Seventy-three strains of the seven recognized Listeria species were studied by performing a multilocus Enzyme Electrophoresis analysis of 18 Enzyme loci. The mean number of alleles per locus was 9.5 and all of the loci were polymorphic. A total of 56 electrophoretic types were distinguished. Cluster analysis of a matrix of the genetic distances between paired electrophoretic types revealed that there were six principal clusters at the species level (genetic distances between clusters greater than 0.8). Listeria monocytogenes, Listeria innocua, Listeria welshimeri, Listeria seeligeri, and Listeria ivanovii each corresponded to one of these clusters with no overlap. Our results are in agreement with those of previous DNA hybridization experiments (Rocourt et al., Curr. Microbiol. 7:383-388, 1982). Listeria grayi and Listeria murrayi electrophoretic types formed a unique cluster, thus reinforcing the suggestion of Wilkinson and Jones (J. Gen. Microbiol. 98:399-421, 1977) that these two species should be considered two biovars of a single species.

Giuliano Gasperi - One of the best experts on this subject based on the ideXlab platform.

Michel Tibayrenc - One of the best experts on this subject based on the ideXlab platform.

  • Multilocus Enzyme Electrophoresis for Parasites and Other Pathogens
    Methods of Molecular Biology, 2009
    Co-Authors: Michel Tibayrenc
    Abstract:

    In this chapter, I expose the main properties and theoretical background of a somewhat out-of-fashion technique, multilocus Enzyme Electrophoresis (MLEE). I show that the remarkable properties of this marker-clear Mendelian inheritance, codominance, strong phylogenetic signal-are still valid, although of course more modern markers now are able to yield far more refined results. MLEE can still be used in many circumstances when a cheap and reliable marker is required. I summarize what have been the main contributions of MLEE to the study of parasites and other pathogens.

  • population structure and genetic typing of trypanosoma cruzi the agent of chagas disease a multilocus Enzyme Electrophoresis approach
    Parasitology, 2000
    Co-Authors: Christian Barnabe, Sylvain Brisse, Michel Tibayrenc
    Abstract:

    A set of 434 Trypanosoma cruzi stocks from a wide ecogeographical range was analysed by Multilocus Enzyme Electrophoresis for 22 genetic loci. Strong linkage disequilibrium, not associated with geographical distance, and 2 main genetic clusters each considerably heterogeneous, was observed. These results support the hypotheses previously proposed that T. cruzi natural populations are composed of highly diversified genetic clones distributed into 2 main phylogenetic lineages: lineage 1, the most ubiquitous in the endemic area, was more frequently observed in sylvatic cycles, whereas lineage 2, predominant in humans and domestic cycles, in the southern part of the area surveyed, was further partitioned into 5 lesser genetic subdivisions. T. cruzi appears therefore subdivided into at least 6 discrete typing units' or DTUs (Tibayrenc, 1998a-c). We have identified various specific isoEnzyme markers (tags'; Tibayrenc, op. fit.) suitable for the routine identification of these DTUs for epidemiological tracking purposes. We discuss the correspondence with previous classifications and with the recent recommendations of the 90th anniversary of the discovery of Chagas disease symposium, as well as the impact of T. cruzi genetic variability on this parasite's hiomedical diversity.

  • identification of six trypanosoma cruzi phylogenetic lineages by random amplified polymorphic dna and multilocus Enzyme Electrophoresis
    International Journal for Parasitology, 2000
    Co-Authors: Sylvain Brisse, Christian Barnabe, Michel Tibayrenc
    Abstract:

    Abstract Genetic characterisation of Trypanosoma cruzi variants is of foremost importance, due to considerable genetic and biological heterogeneity in the parasite populations. Two major phylogenetic lineages, each highly heterogeneous, have been previously described within this species. Here we characterised a geographically and ecologically diverse sample of stocks representative of the breadth of the known clonal diversity of each major lineage, using random amplified polymorphic DNA with 20 primers and multilocus Enzyme Electrophoresis at 22 loci. Molecular hybridisation experiments were performed to control the homology of randomly amplified DNA markers. Both sets of data were highly consistent and supported the existence of two major lineages. Additionally, we found that lineage 2 appeared further partitioned into five sharply delineated phylogenetic clusters, each comprising one of the following reference strains: CanIII cl1 (Z3 reference), M5631 cl5, Esmeraldo cl3 (Z2 reference), CL Brener, and MN cl2. The two first clusters were found mainly in sylvatic environments, whereas the three latter were restricted to domestic transmission cycles and were only collected South to the Amazon Basin. In contrast, lineage 1, which included Miles' Z1 reference strain X10 cl1, was not further subdivided and was encountered across the entire endemic area, in both domestic and sylvatic cycles. Thus, T. cruzi appeared to be subdivided into six discrete typing units, or DTUs, exhibiting distinct geographic and ecological ranges. Reliable diagnostic markers for the two major lineages and the five smaller DTUs of lineage 2 are described, and correspondence with previous classifications of T. cruzi genotypes is given in order to help communication on T. cruzi phylogenetic diversity.

  • evidence for hybridization by multilocus Enzyme Electrophoresis and random amplified polymorphic dna between leishmania braziliensis and leishmania panamensis guyanensis in ecuador
    Journal of Eukaryotic Microbiology, 1997
    Co-Authors: Annelaure Banuls, Ronald H. Guderian, Ramiro Echeverria, F Guerrini, Francois Le Pont, C Barrera, Ivan Espinel, Michel Tibayrenc
    Abstract:

    The taxonomic attribution of four Leishmania stocks isolated from humans in Ecuador has been explored by both multilocus Enzyme Electrophoresis and random amplified polymorphic DNA. For three loci, MLEE results showed patterns suggesting a heterozygous state for a diploid organism, while the corresponding homozygous states are characteristic of the Leishmania panamensis/ guyanensis complex and Leishmania braziliensis, respectively. Other Enzyme loci showed characters attributable to either the L. panamensis/guyanensis complex or L. braziliensis. RAPD profiles exhibited for several primers a combination of the Leishmania panamensis/guyanensis complex and L. braziliensis characters. These data hence suggest that the four stocks are the result of hybridization between L. panamensis/guyanensis and L. braziliensis. MLEE data show that the results cannot be attributed to either mixture of stocks, or an Fl in the framework of a simple Mendelian inheritance.

Patrick Boerlin - One of the best experts on this subject based on the ideXlab platform.

  • Genetic structure of the genus Leptospira by multilocus Enzyme Electrophoresis
    International Journal of Systematic and Evolutionary Microbiology, 1999
    Co-Authors: M Letocart, Patrick Boerlin, F Boerlin-petzold, J Goudet, Guy Baranton, P Perolat
    Abstract:

    Thirty strains from the 11 species of the genus Leptospira were studied by multilocus Enzyme Electrophoresis at 12 Enzyme loci, all of which were polymorphic. The mean number of alleles per locus was 6.5. Twenty-five electrophoretic types were distinguished. Grouping of the strains by cluster analysis was in general agreement with species delineation as determined by DNA-DNA hybridization, except for the strains of Leptospira meyeri and Leptospira inadai, which were scattered throughout the genus, reflecting previously recognized taxonomic uncertainties. Analysis of the clonality within Leptospira interrogans sensu stricto indicated that this population was relatively heterogeneous and a lack of gene linkage disequilibrium could not be excluded. There was a genetic discrimination between the pathogenic species and the saprophytic ones. The phenotypically intermediate species (L. inadai and Leptospira fainei) were also genetically separated and were probably closer to the saprophytes than to the pathogens.

  • Applications of multilocus Enzyme Electrophoresis in medical microbiology
    Journal of Microbiological Methods, 1997
    Co-Authors: Patrick Boerlin
    Abstract:

    Abstract Multilocus Enzyme Electrophoresis has been used since the beginning of the eighties for the study of numerous microbial pathogens. The principles of this technique are presented and its application for the study of population genetics, of systematics, and of molecular epidemiology are discussed. Several examples from the work of the author and from other laboratories illustrate the usefulness of the method in these three fields of medical microbiology. Finally, multilocus Enzyme Electrophoresis is compared with recent methods of molecular biology and the future of multilocus Enzyme Electrophoresis is discussed.

  • Multilocus Enzyme Electrophoresis for characterization of Listeria monocytogenes isolates : results of an international comparative study
    International Journal of Food Microbiology, 1996
    Co-Authors: Dominique A. Caugant, Patrick Boerlin, William F Bibb, W. Donachie, A Gilmour, Fraser E. Ashton, Joseph Harvey, Birgit Nørrung
    Abstract:

    Abstract Multilocus Enzyme Electrophoresis (MEE) is a standard technique that is used to elucidate the epidemiology of a variety of bacterial species. Recently, the method has been employed by several laboratories for investigations of clinical and foodborne isolates of Listeria monocytogenes. To assess the sensitivity and reproducibility of MEE in characterising L. monocytogenes isolates for epidemiological purposes and, ultimately, to agree on a standard protocol, seven laboratories participated in a blinded study of 80 strains. The strain collection included both epidemiologically related and unrelated isolates. Each laboratory used its own protocol for MEE. The number of Enzymes that were assayed by the laboratories ranged from 8 to 23, and the total number of identified electrophoretic types (ETs) varied between 14 and 25. Of the 11 pairs of duplicate strains, the number of pairs recognised as identical by the seven laboratories ranged from 3 to 10 (median = 8). From 10 to 18 (median = 15) of the 22 groups of epidemiological related strains were recognised as homogeneous by the different laboratories. The discriminatory power of the method, calculated using Simpson's index of diversity for 69 strains (80 strains minus the 11 duplicates), ranged from 0.827 to 0.925. This relatively low discriminatory power is a consequence of a somewhat low genetic diversity of L. monocytogenes compared to other bacterial species. Efforts should be pursued to standardise the method in order to improve the intra-and inter-laboratory reproducibility.

  • typing candida albicans oral isolates from human immunodeficiency virus infected patients by multilocus Enzyme Electrophoresis and dna fingerprinting
    Journal of Clinical Microbiology, 1996
    Co-Authors: Patrick Boerlin, J Goudet, F Boerlinpetzold, Christian Durussel, Jeanluc Pagani, J P Chave, Jacques Bille
    Abstract:

    A total of 189 Candida albicans isolates have been typed by multilocus Enzyme Electrophoresis. The results obtained confirm the clonal mode of reproduction of C. albicans. The C. albicans populations found in the oropharynx of human immunodeficiency virus (HIV)-infected patients, in the oropharynx of healthy carriers, or in association with invasive candidiasis could not be distinguished. No clone or group of clones could be associated with the appearance of clinical disorders or with a reduced in vitro susceptibility to the antifungal agent fluconazole. Multiple and sequential oral isolates from 24 HIV-infected patients were also typed by restriction Enzyme analysis with the Enzymes EcoRI and HinfI and by use of the Ca3 repetitive probe. The results obtained by the combination of all three typing methods show that all but one patient each carried a unique major C. albicans clone in their oropharynx. The 21 patients with sequential isolates had the same C. albicans clones in their throats during recurrent oropharyngeal candidiasis episodes, independently of clinical status or of changes of in vitro susceptibility to fluconazole. Finally, several isolates of the same C. albicans clone found simultaneously in the oropharynx of a patient may present different levels of susceptibility to fluconazole.

  • population genetic analysis of borrelia burgdorferi isolates by multilocus Enzyme Electrophoresis
    Infection and Immunity, 1992
    Co-Authors: Patrick Boerlin, Guy Baranton, O Peter, Annegabrielle Bretz, Daniele Postic, Jeanclaude Piffaretti
    Abstract:

    Fifty Borellia burgdorferi strains isolated from humans and ticks in Europe and the United States were analyzed by multilocus Enzyme Electrophoresis. Eleven genetic loci were characterized on the basis of the electrophoretic mobilities of their products. Ten loci were polymorphic. The average number of alleles per locus was 5.9, with a mean genetic diversity of 0.673 among electrophoretic types (ETs). The strains were grouped into 35 ETs constituting three main divisions (I, II, and III) separated at a genetic distance greater than 0.75. Divisions I, II, and III contained 13, 6, and 16 ETs, respectively. These findings, together with previous data from DNA hybridization and restriction Enzyme analysis of rRNA genes, suggest that divisions I, II, and III may represent three distinct genomic species. All three divisions contained human clinical ETs. However, in division I, which includes the ET of the type strain of B. burgdorferi, the human pathogenic ETs constituted a single clone. The ETs of division I were from west-central Europe and the United States, whereas divisions II and III contained ETs from west-central and northern Europe but not from the United States. Finally, our data show that the genetic structure of B. burgdorferi populations is clonal.

L Baruffi - One of the best experts on this subject based on the ideXlab platform.