Browsing by Autor "Michel Tibayrenc"

Now showing 1 - 17 of 17

Additional data on Trypanosoma cruzi isozymic strains encountered in Bolivian domestic transmission cycles
(Oxford University Press, 1986) Michel Tibayrenc; Ary A. Hoffmann; Olivier Poch; Lourdes Echalar; François Le Pont; Jean-Loup Lemesre; P. Desjeux; Francisco J. Ayala
We have collected in Bolivia 212 stocks of Trypanosoma cruzi from domestic transmission cycles and have assayed for nine enzyme systems (11 gene loci). Only a few different isozyme profiles exist, without recombination between them, a situation also encountered in previous Bolivian samples. The 212 stocks, combined with 207 stocks previously studied, have been analysed to uncover any spatial patterns. The frequency of heterozygous strains (2 and 2a) decreases westwards and with increasing altitude. Given that longitude and altitude are correlated with each other, it is not possible to decide which of these two geographic variables is the relevant one, or if both are. These associations might be due to climatic factors. Studies by other authors have shown, however, that heterozygous strains are rare or absent in the Amazon Basin, which is at low altitude.
An isoenzyme study of naturally occurring clones of Trypanosoma cruzi isolated from both sides of the West Andes highland
(Oxford University Press, 1991) Simone Frédérique Brénière; Paul Braquemond; Aldo Solari; Jean‐François Agnèse; Michel Tibayrenc
Seventy-two stocks of Trypanosoma cruzi isolated from both sides of the West Andes highland (Bolivia, Chile and Peru) were analysed by isoenzyme electrophoresis at 12 loci. The data, which were interpreted in terms of population and evolutionary genetics, corroborated the hypothesis of T. cruzi clonal population structure previously proposed, and indicated extensive genetic variability within the taxon T. cruzi. Fifteen different clones (or zymodemes) were identified, which could be grouped into 3 different clusters. Several clones from 2 of these clusters were isolated both in Chile and Bolivia, suggesting a significant circulation of invertebrate and/or vertebrate hosts of T. cruzi between these 2 countries. Low clonal variability in Peru suggested the occurrence of a 'founder effect' in this country. The potential usefulness of a cladistic approach in epidemiology is discussed.
Depressão humoral específica em pacientes crônicos infectados pelo Trypanosoma cruzi
(University of São Paulo, 1984) Simone Frédérique Brénière; Olivier Poch; Hugo Selaes; Michel Tibayrenc; Jean-Loup Lemesre; G Antezana; P. Desjeux
Realizamos um estudo comparativo entre o xenodiagnóstico e os testes sorológicos para a doença de Chagas. Cento e cincoenta pacientes de algumas áreas endêmicas foram estudados. Quatro deles pareceram revelar um estado particular com um xenodiagnóstico positivo e uma sorologia negativa, esta realizada com quatro diferentes técnicas clássicas (teste de immunofluorescência, ELISA: Enzyme Linked Immunosorbent Assay, teste de fixação do complemento e teste de immuno-eletroforese). O soro de um dos pacientes que apresentou depressão humoral específica mostra elevada quantidade de antígenos circulantes comprovada pela técnica da immuno-eletroforese. Os Autores sugerem o uso de um teste sorológico para detectar a presença de antígenos circulantes de T. cruzi, além da utilização de testes sorológicos clássicos. Isto permitiria o diagnóstico da doença de Chagas em pacientes com uma baixa (ou mesmo inexistente) produção de anticorpos específicos.
Diagnosis by Isozyme Methods of Two Cryptic Species, Psychodopygus Carrerai and P. Yucumensis (Diptera: Psychodidae)1
(Oxford University Press, 1986) T. Caillard; Michel Tibayrenc; François Le Pont; Jean‐Pierre Dujardin; P. Desjeux; F.J. Ayala
Journal Article Diagnosis by Isozyme Methods of Two Cryptic Species, Psychodopygus Carrerai and P. Yucumensis (Diptera: Psychodidae) Get access T. Caillard, T. Caillard 2Instituto Boliviano de Biología de Altura (IBBA), Embajada de Francia, Casilla 824, La Paz, Bolivia. Send reprint requests to this address Search for other works by this author on: Oxford Academic PubMed Google Scholar M. Tibayrenc, M. Tibayrenc 3IBBA, and SSC ORSTOM, 70-74 route d'Aulnay, 93140 Bondy, France6Department of Genetics, University of California, Davis, California 95616, USA. Search for other works by this author on: Oxford Academic PubMed Google Scholar F. Le Pont, F. Le Pont 3IBBA, and SSC ORSTOM, 70-74 route d'Aulnay, 93140 Bondy, France Search for other works by this author on: Oxford Academic PubMed Google Scholar J.P. Dujardin, J.P. Dujardin 4IBBA, and Institut de Médecine tropicale “Prince Leopold,” 155 Nationalestraat, B-2000 Antwerpen, Belgium Search for other works by this author on: Oxford Academic PubMed Google Scholar P. Desjeux, P. Desjeux 5IBBA, and Institut Pasteur, 28 rue du Docteur Roux, 75015 Paris, France Search for other works by this author on: Oxford Academic PubMed Google Scholar F.J. Ayala F.J. Ayala 6Department of Genetics, University of California, Davis, California 95616, USA. Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Medical Entomology, Volume 23, Issue 5, 19 September 1986, Pages 489–492, https://doi.org/10.1093/jmedent/23.5.489 Published: 19 September 1986
Different Behavior of TwoTrypanosoma cruziMajor Clones: Transmission and Circulation in Young Bolivian Patients
(Elsevier BV, 1998) Simone Frédérique Brénière; Marie-France Bosseno; Jenny Telleria; Brigitte Bastrenta; Nina Yacsik; François Noireau; Jose-Luis Alcazar; Christian Barnabé; Patrick Wincker; Michel Tibayrenc
Dispersing behaviour of T. infestans: evidence from a genetical study of field populations in Bolivia
(Instituto Oswaldo Cruz, Ministério da Saúde, 1988) Jean‐Pierre Dujardin; C. La Fuente; L. Cardozo; Michel Tibayrenc
Experimental Trypanosoma cruzi biclonal infection in Triatoma infestans: detection of distinct clonal genotypes using kinetoplast DNA probes
(Elsevier BV, 2000) Artur da Silveira Pinto; Marta de Lana; Constança Britto; Brigitte Bastrenta; Michel Tibayrenc
Genetic Characterization of Trypanosoma cruzi DTUs in Wild Triatoma infestans from Bolivia: Predominance of TcI
(Public Library of Science, 2012) Simone Frédérique Brénière; Claudia Aliaga; Etienne Waleckx; Rosio Buitrago; Renata Salas; Christian Barnabé; Michel Tibayrenc; François Noireau
By exploring large-scale DTUs that infect the wild populations of T. infestans, this study opens the discussion on the origin of TcI and TcV DTUs that are predominant in domestic Bolivian cycles.
Genetic Variation and Exchange in Trypanosoma cruzi Isolates from the United States
(Public Library of Science, 2013) Dawn M. Roellig; Mason Y. Savage; Atsushi Fujita; Christian Barnabé; Michel Tibayrenc; Frank Steurer; Michael J. Yabsley
Trypanosoma cruzi, the causative agent of Chagas disease, is a multiclonal parasite with high levels of genetic diversity and broad host and geographic ranges. Molecular characterization of South American isolates of T. cruzi has demonstrated homologous recombination and nuclear hybridization, as well as the presence of 6 main genetic clusters or "discrete typing units" (DTUs). Few studies have extensively investigated such exchange events and genetic diversity in North American isolates. In the current study, we genetically characterized over 50 US isolates from wildlife reservoirs (e.g., raccoons, opossums, armadillos, skunks), domestic dogs, humans, nonhuman primates, and reduviid vectors from nine states (TX, CA, OK, SC, FL, GA, MD, LA, TN) using a multilocus sequencing method. Single nucleotide polymorphisms were identified in sequences of the mismatch-repair class 2 (MSH2) and Tc52 genes. Typing based on the two genes often paralleled genotyping by classic methodologies using mini-exon and 18S and 24Sα rRNA genes. Evidence for genetic exchange was obtained by comparing sequence phylogenies of nuclear and mitochondrial gene targets, dihydrofolate reductase-thymidylate synthase (DHFR-TS) and the cytochrome oxidase subunit II- NADH dehydrogenase subunit I region (COII-ND1), respectively. We observed genetic exchange in several US isolates as demonstrated by incongruent mitochondrial and nuclear genes phylogenies, which confirms a previous finding of a single genetic exchange event in a Florida isolate. The presence of SNPs and evidence of genetic exchange illustrates that strains from the US are genetically diverse, even though only two phylogenetic lineages have been identified in this region.
In Vitro Benznidazole and Nifurtimox Susceptibility Profile of Trypanosoma cruzi Strains Belonging to Discrete Typing Units TcI, TcII and TcV
(2019) Suzana Revollo; Bruno Oury; Andrea Vela; Michel Tibayrenc; Denis Séréno
We ascertain the in vitro Benznidazole (BZN) and Nifurtimox (NFX) susceptibility pattern of epimastigotes, trypomastigotes, and amastigotes of 21 T. cruzi strains, from patients, reservoir and triatomine bugs of various geographic origin. Using this panel of isolates, we compute the Epidemiological cut off value (COwt). Then, the frequency of the susceptible phenotype (Wild type) towards BZN and nifurtimox (NFX) within this set of strains belonging to 3 discrete typing units (DTUs), TcI, TcII, and TcV was deduced. We have observed that the susceptibility status of individual T. cruzi isolates toward BZN and NFX is related to the genetic background and to underlying factors probably related to the individual life trait history of each strain. Analyzing drug susceptibility in this conceptual framework would offers the possibility to evidence a link between isolates expressing a low susceptibility level (not wild-type) as define by the COwt value and none-curative treatment. It will also permit to tract drug-resistant parasites in T. cruzi population.
In Vitro Benznidazole and Nifurtimox Susceptibility Profile of Trypanosoma cruzi Strains Belonging to Discrete Typing Units TcI, TcII, and TcV
(Multidisciplinary Digital Publishing Institute, 2019) Susana Revollo; Bruno Oury; Andrea Vela; Michel Tibayrenc; Denis Séréno
We ascertain the in vitro Benznidazole (BZN) and Nifurtimox (NFX) susceptibility pattern of epimastigotes, trypomastigotes, and amastigotes of 21 T. cruzi strains, from patients, reservoir, and triatomine bugs of various geographic origins. Using this panel of isolates, we compute the Epidemiological cut off value (COwt). Then, the frequency of the susceptible phenotype (Wild type) towards benznidazole (BZN) and nifurtimox (NFX) within this set of strains belonging to three discrete typing units (DTUs), TcI, TcII, and TcV, was deduced. We observed that the susceptibility status of individual T. cruzi isolates toward BZN and NFX is related to the genetic background and underlying factors that are probably related to the individual life trait history of each strain. Analyzing drug susceptibility in this conceptual framework would offer the possibility to evidence a link between isolates expressing a low susceptibility level (not wild-type) as defined by the COwt value and none-curative treatment. It will also permit us to track drug-resistant parasites in the T. cruzi population.
Interest and limitations of Spliced Leader Intergenic Region sequences for analyzing Trypanosoma cruzi I phylogenetic diversity in the Argentinean Chaco
(Elsevier BV, 2010) Nicolás Tomasini; Juan José Lauthier; María M. Monje Rumi; Paula G. Ragone; A. ALBERTI D'AMATO; Cecilia Pérez Brandán; Carolina Cura; Alejandro G. Schijman; Christian Barnabé; Michel Tibayrenc
Isozyme Evidence of Lack of Speciation Between Wild and Domestic Triatoma Infestans (Heteroptera: Reduviidae) in Bolivia1
(Oxford University Press, 1987) Jean Dujardin; Michel Tibayrenc; Evaristo Venegas; Liliana Ximena Muñoz Maldonado; P. Desjeux; Francisco J. Ayala
Wild and domestic Triatoma infestans from the Cochabamba region of Bolivia were virtually identical at 19 gene loci coding for enzymes. No allele was distinctive of either the wild or the domestic populations. Hence, there is no evidence that the 2 populations are different species. Domestic populations separated by 20 km showed statistically significant differences in allelic frequencies; this is compatible with the hypothesis of other authors that migrations of T. infestans are limited when feeding conditions are satisfactory. Fifteen trypanosomatid stocks isolated from wild T. infestans were shown by isozyme analysis to be Trypanosoma cruzi. This provides evidence that wild T. infestans are involved in the Chagas' disease cycle. The T. cruzi isozymic strains from wild T. infestans were genetically similar to those isolated from domestic T. infestans in the same region. This supports the hypothesis that there is no speciation between wild and domestic T. infestans, and that wild and domestic T. cruzi cycles may overlap in this region.
Karyotype plasticity in NeotropicalLeishmania: an index for measuring genomic distance amongL. (V.) peruvianaandL. (V.) braziliensispopulations
(Cambridge University Press, 1995) Jean‐Claude Dujardin; Jean‐Pierre Dujardin; Michel Tibayrenc; G. Timperman; Simonne De Doncker; D. Jacquet; Jorge Arévalo; Alejandro Llanos‐Cuentas; Humberto Guerra; Harry Bermudez
A method for phenetic analysis of karyotype data has been developed for Leishmania populations. Measurement of size difference between chromosomes recognized by a given DNA probe in different isolates led to the formulation of a Chromosome Size Difference Index (CSDI). The method was applied to phenetic analysis of 4 sets of chromosomes--each set being recognized by a different probe--in 37 L. (Viannia) peruviana isolates sampled along a North-South transect through the Peruvian Andes and, in 11 L. (V.) braziliensis isolates from the Amazonian forest (Peru, Bolivia and Brazil). Karyotype variability was better accounted for by CSDI than by a method based on disjunctive encoding of karyotype data. CSDI evidenced the nature of relationships between L. braziliensis and L. peruviana and it provided a coherent picture of geographical and genomic differentiation among parasite populations. The latter did cluster according to their geographical origin. L. braziliensis was found karyotypically more homogeneous than L. peruviana. Within L. peruviana, Northern populations were closer to L. braziliensis than to Southern L. peruviana populations. The validity of karyotypic populations, or karyodemes, was sustained.
Les hôtes naturels deTrypanosomacruzi en Guyane Française
(EDP Sciences, 1985) J. P. Dedet; Jean‐Philippe Chippaux; P. Goyot; Franck Pajot; Michel Tibayrenc; Bernard Geoffroy; Hervé Gosselin; P. Jacquet-Vialet
During an epidemiological survey in French Guiana, three species of Marsupiala were found infected by Trypanosoma cruzi with high infection rates (30,8% for Didelphis marsupialis). Six Triatomine bug species were recorded, five of them being well known vectors of Chagas' disease. Iso-enzyme characterization of 22 stocks isolated (16 from D. marsupialis, 3 from Philander opossum and 3 from Rhodnius prolixus) revealed that they were all related to zymodeme 1 of Miles. The silvatic cycle is endemic in the various ecotopes studied. The high prevalence rates of infection in D. marsupialis in the human settlement of Cacao and the finding in this locality of domestic breeding of Rhodnius pictipes lead to suspect the occurrence of a peridomestic cycle in this village. The evidence of R. prolixus colonizing houses in the vicinity of Cayenne emphasizes the risk of Chagas' disease in French Guiana.
Metric Differences Between Silvatic and Domestic Triatoma infestans (Heteroptera: Reduviidae) in Bolivia
(Oxford University Press, 1997) Jean Dujardin; Harry Bermudez; CE Casini; Christopher J. Schofield; Michel Tibayrenc
One hundred and fifty-seven specimens of Bolivian Triatoma infestans (Klug 1834), including 44 from the silvatic focus at Cochabamba (Bolivia), were compared using morphometric characters of the head capsule. From these specimens, 10 silvatic and 28 domestic adults were also compared using additional morphometric characters of the membranous part of the hemelytra. Nonparametric univariate comparisons between specimens from silvatic and domestic ecotopes indicated the importance of the postocular region as a possible diagnostic character for nymphs and adults from the different ecotopes, and they detected wing differences in males. Populations became more distinct entities when head or wing characters were considered jointly in canonical variate analysis. Regardless of whether size variation was considered, canonical variate analysis generally showed greater significance for wing than for head features. These morphological differences between silvatic and domestic bugs, particularly unrelated to size differences, are interpreted to indicate incipient separation between silvatic and domestic populations that had not been detected by previous isoenzyme analyses, and suggest a reinterpretation of the epidemiological significance of silvatic populations of T. infestans in Bolivia.
Smallness of the Panmictic Unit of Triatoma infestans (Hemiptera: Reduviidae)
(Oxford University Press, 1998) Simone Frédérique Brénière; Marie-France Bosseno; Fernando Regla Vargas; Nina Yaksic; François Noireau; Sébastien Noël; Jean‐Pierre Dujardin; Michel Tibayrenc
The population genetic structure of Triatoma infestans (Klug), the principal vector of the causative agent of Chagas disease in Bolivia, was investigated by enzyme electrophoresis at 15 loci, of which 3 were polymorphic. A total of 1,286 adults and nymphs was collected from 19 localities of the Cochabamba (high endemicity) and La Paz (low endemicity) departments. Previous results were confirmed, including a low level of polymorphism (0.20), low genetic distance between geographic areas, and a population structure compatible with an isolation by distance model. However, a high proportion (26.3%) of the surveyed localities showed a significant excess of homozygotes, disputing previous conclusions that considered the village as the probable panmictic unit. The excess of homozygotes was reduced when smaller subunits, such as individual houses or chicken coops, were considered, indicating a Wahlund effect.