RESUMO
In situ fluorometers were deployed during the Deepwater Horizon (DWH) Gulf of Mexico oil spill to track the subsea oil plume. Uncertainties regarding instrument specifications and capabilities necessitated performance testing of sensors exposed to simulated, dispersed oil plumes. Dynamic ranges of the Chelsea Technologies Group AQUAtracka, Turner Designs Cyclops, Satlantic SUNA and WET Labs, Inc. ECO, exposed to fresh and artificially weathered crude oil, were determined. Sensors were standardized against known oil volumes and total petroleum hydrocarbons and benzene-toluene-ethylbenzene-xylene measurements-both collected during spills, providing oil estimates during wave tank dilution experiments. All sensors estimated oil concentrations down to 300 ppb oil, refuting previous reports. Sensor performance results assist interpretation of DWH oil spill data and formulating future protocols.
Assuntos
Monitoramento Ambiental/instrumentação , Poluição por Petróleo/análise , Petróleo/análise , Benzeno , Fluorometria/instrumentação , Hidrocarbonetos , México , Dispositivos Ópticos , Tolueno , Movimentos da Água , Tempo (Meteorologia) , XilenosRESUMO
Trypanosoma cruzi and Trypanosoma rangeli are human-infective blood parasites, largely restricted to Central and South America. They also infect a wide range of wild and domestic mammals and are transmitted by a numerous species of triatomine bugs. There are significant overlaps in the host and geographical ranges of both species. The two species consist of a number of distinct phylogenetic lineages. A range of PCR-based techniques have been developed to differentiate between these species and to assign their isolates into lineages. However, the existence of at least six and five lineages within T. cruzi and T. rangeli, respectively, makes identification of the full range of isolates difficult and time consuming. Here we have applied fluorescent fragment length barcoding (FFLB) to the problem of identifying and genotyping T. cruzi, T. rangeli and other South American trypanosomes. This technique discriminates species on the basis of length polymorphism of regions of the rDNA locus. FFLB was able to differentiate many trypanosome species known from South American mammals: T. cruzi cruzi, T. cruzi marinkellei, T. dionisii-like, T. evansi, T. lewisi, T. rangeli, T. theileri and T. vivax. Furthermore, all five T. rangeli lineages and many T. cruzi lineages could be identified, except the hybrid lineages TcV and TcVI that could not be distinguished from lineages III and II respectively. This method also allowed identification of mixed infections of T. cruzi and T. rangeli lineages in naturally infected triatomine bugs. The ability of FFLB to genotype multiple lineages of T. cruzi and T. rangeli together with other trypanosome species, using the same primer sets is an advantage over other currently available techniques. Overall, these results demonstrate that FFLB is a useful method for species diagnosis, genotyping and understanding the epidemiology of American trypanosomes.
Assuntos
Trypanosoma/genética , Animais , Genótipo , Reação em Cadeia da Polimerase , América do Sul , Especificidade da EspécieRESUMO
In an effort to unify the nomenclature of Trypanosoma cruzi, the causative agent of Chagas disease, an updated system was agreed upon at the Second Satellite Meeting. A consensus was reached that T. cruzi strains should be referred to by six discrete typing units (T. cruzi I-VI). The goal of a unified nomenclature is to improve communication within the scientific community involved in T. cruzi research. The justification and implications will be presented in a subsequent detailed report.
Assuntos
Terminologia como Assunto , Trypanosoma cruzi/classificação , AnimaisRESUMO
Trypanosoma cruzi is the protozoan agent of Chagas disease, and the most important parasitic disease in Latin America. Protozoa of the genus Leishmania are global agents of visceral and cutaneous leishmaniasis, fatal and disfiguring diseases. In the 1970s multilocus enzyme electrophoresis demonstrated that T. cruzi is a heterogeneous complex. Six zymodemes were described, corresponding with currently recognized lineages, TcI and TcIIa-e--now defined by multiple genetic markers. Molecular epidemiology has substantially resolved the phylogeography and ecological niches of the T. cruzi lineages. Genetic hybridization has fundamentally influenced T. cruzi evolution and epidemiology of Chagas disease. Genetic exchange of T. cruzi in vitro involves fusion of diploids and genome erosion, producing aneuploid hybrids. Transgenic fluorescent clones are new tools to elucidate molecular genetics and phenotypic variation. We speculate that pericardial sequestration plays a role in pathogenesis. Multilocus sequence typing, microsatellites and, ultimately, comparative genomics are improving understanding of T. cruzi population genetics. Similarly, in Leishmania, genetic groups have been defined, including epidemiologically important hybrids; genetic exchange can occur in the sand fly vector. We describe the profound impact of this parallel research on genetic diversity of T. cruzi and Leishmania, in the context of epidemiology, taxonomy and disease control.
Assuntos
Doença de Chagas/epidemiologia , Leishmania , Leishmaniose/epidemiologia , Epidemiologia Molecular , Filogenia , Trypanosoma cruzi , Animais , Doença de Chagas/parasitologia , Doença de Chagas/transmissão , Ecossistema , Leishmania/classificação , Leishmania/genética , Leishmaniose/parasitologia , Leishmaniose/transmissão , América do Sul/epidemiologia , Trypanosoma cruzi/classificação , Trypanosoma cruzi/genéticaRESUMO
Parasites of wild primates are important for conservation biology and human health due to their high potential to infect humans. In the Amazon region, non-human primates are commonly infected by Trypanosoma cruzi and T. rangeli, which are also infective to man and several mammals. This is the first survey of trypanosomiasis in a critically endangered species of tamarin, Saguinus bicolor (Callitrichidae), from the Brazilian Amazon Rainforest. Of the 96 free-ranging specimens of S. bicolor examined 45 (46.8%) yielded blood smears positive for trypanosomes. T. rangeli was detected in blood smears of 38 monkeys (39.6%) whereas T. cruzi was never detected. Seven animals (7.3%) presented trypanosomes of the subgenus Megatrypanum. Hemocultures detected 84 positive tamarins (87.5%). Seventy-two of 84 (85.7%) were morphologically diagnosed as T. rangeli and 3 (3.1%) as T. cruzi. Nine tamarins (9.4%) yielded mixed cultures of these two species, which after successive passages generated six cultures exclusively of T. cruzi and two of T. rangeli, with only one culture remaining mixed. Of the 72 cultures positive for T. rangeli, 62 remained as established cultures and were genotyped: 8 were assigned to phylogenetic lineage A (12.9%) and 54 to lineage B (87.1%). Ten established cultures of T. cruzi were genotyped as TCI lineage (100%). Transmission of both trypanosome species, their potential risk to this endangered species and the role of wild primates as reservoirs for trypanosomes infective to humans are discussed.
Assuntos
Animais Selvagens/parasitologia , Conservação dos Recursos Naturais , Doenças dos Macacos , Saguinus/parasitologia , Trypanosoma cruzi , Trypanosoma , Tripanossomíase/veterinária , Animais , Brasil/epidemiologia , Doença de Chagas/parasitologia , Doença de Chagas/veterinária , Genótipo , Doenças dos Macacos/epidemiologia , Doenças dos Macacos/parasitologia , Reação em Cadeia da Polimerase/métodos , Prevalência , Árvores , Trypanosoma/classificação , Trypanosoma/genética , Trypanosoma/isolamento & purificação , Trypanosoma/patogenicidade , Trypanosoma cruzi/classificação , Trypanosoma cruzi/genética , Trypanosoma cruzi/isolamento & purificação , Trypanosoma cruzi/patogenicidade , Tripanossomíase/epidemiologia , Tripanossomíase/parasitologiaRESUMO
Five hundred thirty soybean accessions from maturity groups (MG) III through IX were evaluated for resistance to Phakopsora pachyrhizi in a replicated field trial at Centro Regional de Investigación Agrícola in Capitán Miranda, Itapúa, Paraguay during the 2005-06 season. Soybean rust severities of individual accessions ranged from 0% (resistant) to 30.0% (susceptible). In MG III and IV, the most resistant accessions were PI 506863, PI 567341, and PI 567351B, with severities less than 1.2%. In MG V, the most resistant accessions were PI 181456, PI 398288, PI 404134B, and PI 507305, with severities less than 0.3%. In MG VI, the most resistant accessions were PI 587886, PI 587880A, and PI 587880B, with severities less than 0.3%. In MG VII and VIII, the most resistant were PI 587905 and PI 605779E, with severities less than 1.0%. In MG IX, the most resistant accessions were PI 594754, PI 605833, PI 576102B, and PI 567104B, with severities less than 1.0%. The resistance in 10 selected accessions from MG VI, VII, VIII, and XI was confirmed in subsequent greenhouse and field experiments where severities of 0.4% or less and reddish-brown lesions with sporulation levels less than 3.0 were observed. These accessions, with low severities in the adult plant field evaluation, may be new sources of resistance to P. pachyrhizi.
RESUMO
Phakopsora pachyrhizi Syd. & P. Syd., the cause of soybean rust, was first observed on soybean (Glycine max (L.) Merr.) in South America in the district of Itapúa in Paraguay during March, 2001 (2). The disease is now widespread in soybean-production areas in South America on soybean and kudzu (Pueraria lobata (Willd.) Ohwi). On 15 March 2006, leaves of the perennial legume Neonotonia wightii (Graham ex Wight & Arn.) Lackey with lesions and rust sori were observed in the Reserva Biológica de Itabó, Departamento Alto Paraná. Lesions were scattered, most contained a single uredinium, mostly hypophyllous, and appeared to be new infections. Lesions with several uredinia, which are indicative of older infections on soybean, were also observed. Sori (Malupa-type) contained hyaline, peripheral, cylindric to clavate paraphyses measuring 24 to 45 × 6 to 13 µm and urediniospores that were hyaline, ovoid to globose, and measuring 20 to 40 × 14 to 25 µm with an echinulate spore wall, characteristics typical of a Phakopsora sp. DNA extracted from sori from leaves of N. wightii was amplified in a real-time fluorescent polymerase chain reaction with the P. pachyrhizi-specific primers Ppm1 and Ppa2 (1). Sequence alignment of the internal transcribed spacer region 2 further confirmed the identification as P. pachyrhizi (1). The host identification was confirmed by J. Kirkbride, USDA/ARS/SBML, using the Smithsonian Institution Department of Botany, U.S. National Herbarium. To our knowledge, this is the first confirmed report of natural infection of P. pachyrhizi on a host other than soybean or kudzu in South America. Voucher specimens were deposited in the herbarium of the Facultad Ciencias Químicas of the Universidad Nacional de Asunción of Paraguay (FCQ) and the National Fungus Collection (Accession No. BPI 875340). References: (1) R. D. Frederick et al. Phytopathology 92:217, 2002. (2) W. Morel and J. Yorinori. Bol. Divulg. No. 44. Ministerio de Agricultura y Ganadería, Centro Regional de Investigación Agrícola, Capitán Miranda, Paraguay, 2002.
RESUMO
Most Rhodnius species (Triatominae) are primarily associated with palm trees. They maintain enzootic Trypanosoma cruzi transmission and are responsible for human infection (causing Chagas disease) through the Neotropics. Assessing whether individual palm traits (ecological and/or botanical) may increase the risk of palm infestation by triatomines is relevant in areas where bugs invade houses flying from peridomestic palms. We developed a novel fieldwork approach with that objective, and applied it to study infestation by sylvatic Rhodnius ecuadoriensis in 110 tagua palms (Phytelephas aequatorialis). Palm infestation (23% overall) was non-randomly distributed in our sample. Palms located in anthropic landscapes were frequently infested (>27%, n=92), whereas no bugs were collected from palms surveyed within forest remnants (n=18; P=0.01). The presence of abundant decaying vegetable matter (P=0.001) and (to a lesser extent) epiphytic plants (P=0.049) on palm crowns and stems increased the probability of infestation and was positively correlated with the apparent density of bug colonies (R2=0.68). A trend towards higher infestation rates in male palms (34% vs. 18%) could relate to female palm management (removal of infrutescences and vegetable debris) in areas where palm seeds are harvested. An outline of 'risk palm ecotopes' and environmental management-based strategies for the control of peridomestic, palm tree-living vector populations are proposed.
Assuntos
Ecossistema , Insetos Vetores/fisiologia , Doenças das Plantas/parasitologia , Rhodnius/fisiologia , Árvores/parasitologia , Animais , Doença de Chagas/epidemiologia , Doença de Chagas/transmissão , Equador/epidemiologia , Humanos , Fatores de RiscoRESUMO
The distribution of selected hydrocarbons within ten dated sediment cores taken from the Mississippi River Bight off coastal Louisiana suggests a chronic contaminant loading from several sources including the river itself, oil and gas exploration in the central Gulf of Mexico (GOM) shelf area, and natural geologic hydrocarbon seeps. Data were grouped as either total polycyclic aromatic hydrocarbons (PAH's), which were indicative of pyrogenic PAH's; or estimated total hopanes (indicative of petrogenic hydrocarbons). The total PAH concentrations and estimated total hopanes begin increasing above background levels (approximately 200 ng g(-1)) after the 1950s. The distribution of these hydrocarbons and hopanes within the dated sediment cores suggests that the Mississippi River is a regional source of pyrogenic PAH's, and that the hopanes are from natural geologic hydrocarbon seeps, oil and gas exploration in the GOM, or both.
Assuntos
Sedimentos Geológicos/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Oceano Atlântico , Monitoramento Ambiental , Indústrias , México , Petróleo , Rios , Água do Mar , TexasRESUMO
A new species of the genus Linshcosteus Distant, 1904 (Hemiptera: Reduviidae: Triatominae) is described from specimens collected near Kalakkadu, Tamil Nadu state, southern India. Specimens were found in deep crevices between rocks, in a region of semi-arid scrub jungle. The distinctiveness of the new species was demonstrated by a morphometric analysis including the five previously described species of Linshcosteus, all from India. Nine measurements of the head were used in an isometric size-free principal component analysis. In terms of discrete morphology the new species, Linshcosteus karupus sp.n. Galvão, Patterson, Rocha & Jurberg differs from the most similar one, L. kali Lent & Wygodzinsky, 1979, by its very prominent anterolateral projections of the pronotum, by the length to width ratio of the pronotum, by the pilosity of the head and several other characters, including phallic structures. A revised key is presented for the six species of the genus.
Assuntos
Triatominae/classificação , Animais , Feminino , Índia , Masculino , Filogenia , Especificidade da Espécie , Triatominae/anatomia & histologiaRESUMO
Comparative ELISA and selective immunoblotting procedures were used in attempts to identify differential serological indicators of infection with the Leishmania (Viannia) braziliensis complex, infection with the L. braziliensis species, and therapeutic cure of localized or mucocutaneous leishmaniasis (LCL or MCL). Although mean ELISA absorbance values were significantly higher for MCL sera than for LCL sera, absorbance could not be used as a reliable indicator of the clinical form of disease. Immunoblotting profiles were similar with sera from MCL and LCL. Pre-adsorption with heterologous trypanosomatid antigens indicated that recognition of antigens of about 56, 60, 66, 72, 88 and 110 kDa might be specific to the subgenus Viannia. In two-colour, sequential, dual ELISA-based immunoblotting, no antigens recognized only by sera from MCL patients were detected. After glucantime therapy, immunoblotting profiles with LCL sera were reduced both in intensity and in the range of antigens detected; a 104-kDa antigen was newly detected with post-treatment LCL sera. Overall, the results show the value of differential immunological detection strategies and support the close relationship between species of the subgenus Viannia but fail to indicate a prognostic antigen for MCL.
Assuntos
Antígenos de Protozoários/imunologia , Leishmania braziliensis/imunologia , Leishmaniose Mucocutânea/imunologia , Animais , Antígenos de Protozoários/efeitos dos fármacos , Antiprotozoários/uso terapêutico , Biomarcadores/sangue , Western Blotting , Estudos de Casos e Controles , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Humanos , Leishmania braziliensis/efeitos dos fármacos , Leishmaniose Mucocutânea/tratamento farmacológico , Meglumina/uso terapêutico , Antimoniato de Meglumina , Compostos Organometálicos/uso terapêuticoRESUMO
Chagas disease control strategies strongly depend on the triatomine vector species involved in Trypanosoma cruzi transmission within each area. Here we report the results of the identification of specimens belonging to various species of Triatominae captured in Ecuador (15 species from 17 provinces) and deposited in the entomological collections of the Catholic University of Ecuador (Quito), Instituto Oswaldo Cruz (Brazil), the Natural History Museum London (UK), the London School of Hygiene and Tropical Medicine (UK), the National Institute of Hygiene (Quito), and the Vozandes Hospital (Quito). A critical review of published information and new field records are presented. We analysed these data in relation to the life zones where triatomines occur (11 life zones, excluding those over 2,200 m altitude), and provide biogeographical maps for each species. These records are discussed in terms of epidemiological significance and design of control strategies. Findings relevant to the control of the main vector species are emphasised. Different lines of evidence suggest that Triatoma dimidiata is not native to Ecuador-Peru, and that synanthropic populations of Rhodnius ecuadoriensis in southern Ecuador-northern Peru might be isolated from their sylvatic conspecifics. Local eradication of T. dimidiata and these R. ecuadoriensis populations might therefore be attainable. However, the presence of a wide variety of native species indicates the necessity for a strong longitudinal surveillance system.
Assuntos
Doença de Chagas/prevenção & controle , Insetos Vetores/classificação , Triatominae/classificação , Animais , Doença de Chagas/epidemiologia , Equador/epidemiologia , Meio Ambiente , Panstrongylus/classificação , Densidade Demográfica , Rhodnius/classificação , Triatoma/classificaçãoRESUMO
We conducted a survey to determine the vectors of malaria in six localities of Serra do Navio municipality, State of Amapá, from 1990 to 1991. Malaria infection rates of 29.3%, 6.2% and 20.4% were detected by human blood smears in Colônia Agua Branca, Porto Terezinha and Arrependido, respectively. There was no malaria infection detected in Serra do Navio. Fifteen species were identified among 3,053 anopheline mosquitoes collected by human bait and 64.4% were identified as Anopheles albitarsis s.l., 16.7% An. braziliensis, 9.5% An. nuneztovari and 5.8% An. triannulatus. An. darlingi, the main vector of malaria in the Amazon region of Brazil, was scare. Using enzyme-linked immunosorbent assay (ELISA), a total positive rate of 0.8% (23/2876) was found for six species: fifteen An. albitarsis s.l., four An. nuneztovari, and one of each: An. braziliensis, An. triannulatus, An. oswaldoi and An. rangeli. Nine of 23 positive mosquitoes were infected with Plasmodium malariae, eight with P. vivax VK210, three with P. vivax VK247 and three with P. falciparum. Since An. albitarsis s.l. was collected feeding on humans, was present in the highest density and was positive by ELISA for malaria sporozoites, it probably plays an important role in malaria transmission in this area.
Assuntos
Anopheles/parasitologia , Insetos Vetores/parasitologia , Malária/transmissão , Plasmodium/isolamento & purificação , Animais , Brasil , Ensaio de Imunoadsorção Enzimática , Humanos , Estações do AnoRESUMO
We conducted a survey to determine the vectors of malaria in six localities of Serra do Navio municipality, State of Amapá, from 1990 to 1991. Malaria infection rates of 29.3 percent, 6.2 percent and 20.4 percent were detected by human blood smears in Colônia ægua Branca, Porto Terezinha and Arrependido, respectively. There was no malaria infection detected in Serra do Navio. Fifteen species were identified among 3,053 anopheline mosquitoes collected by human bait and 64.4 percent were identified as Anopheles albitarsis s.l., 16.7 percent An. braziliensis, 9.5 percent An. nuneztovari and 5.8 percent An. triannulatus. An. darlingi, the main vector of malaria in the Amazon region of Brazil, was scare. Using enzyme-linked immunosorbent assay (ELISA), a total positive rate of 0.8 percent (23/2876) was found for six species: fifteen An. albitarsis s.l., four An. nuneztovari, and one of each: An. braziliensis, An. triannulatus, An. oswaldoi and An. rangeli. Nine of 23 positive mosquitoes were infected with Plasmodium malariae, eight with P. vivax VK210, three with P. vivax VK247 and three with P. falciparum. Since An. albitarsis s.l. was collected feeding on humans, was present in the highest density and was positive by ELISA for malaria sporozoites, it probably plays an important role in malaria transmission in this area
Assuntos
Humanos , Animais , Anopheles/parasitologia , Insetos Vetores/parasitologia , Malária/transmissão , Plasmodium/isolamento & purificação , Brasil , Ensaio de Imunoadsorção Enzimática , Estações do AnoRESUMO
Quantitative analysis of morphological characters of the head was used to reconstruct the evolutionary history of the tropicopolitan bug Triatoma rubrofasciata (De Geer) (Hemiptera: Reduviidae) and seven species of Old World Triatoma. Multivariate analysis demonstrates that T. rubrofasciata and the Old World species have a high degree of similarity with Nearctic Triatoma species, particularly T. rubida (Uhler). We interpret this to imply a common ancestry for these groups. Dissemination of T. rubrofasciata and subsequent derivation of the Old World species of Triatoma is deduced to have occurred over a period of not more than 350 years.
Assuntos
Filogenia , Triatoma/anatomia & histologia , Animais , Sudeste Asiático , Evolução Biológica , Brasil , Feminino , Havaí , Processamento de Imagem Assistida por Computador , Índia , Análise Multivariada , Ilhas do Pacífico , Estatísticas não Paramétricas , Triatoma/classificação , Triatoma/genética , Gravação em Vídeo , Índias OcidentaisRESUMO
Analysis of restriction fragment length polymorphism (RFLP) profiles derived from digestion of polymerase chain reaction (PCR) products of the ribosomal 18S from Trypanosoma cruzi yields a typical 'riboprint' profile that can vary intraspecifically. A selection of 21 stocks of T. cruzi and three outgroup taxa: T. rangeli, T. conorhini and Leishmania braziliensis were analysed by riboprinting to assess divergence within and between taxa. T. rangeli, T. conorhini and L. braziliensis could be easily differentiated from each other and from T. cruzi. Phenetic analysis of PCR-RFLP profiles indicated that, with one or two exceptions, stocks of T. cruzi could be broadly partitioned into two groups that formally corresponded to T. cruzi I and T. cruzi II respectively. To test if ribosomal 18S sequences were homogeneous within each taxon, gradient gel electrophoresis methods were employed utilising either chemical or temperature gradients. Upon interpretation of the melting profiles of riboprints and a section of the 18S independently amplified by PCR, there would appear to be at least two divergent 18S types present within T. cruzi. Heterogeneity within copies of the ribosomal 18S within a single genome has therefore been demonstrated and interestingly, this dimorphic arrangement was also present in the outgroup taxa. Presumably the ancestral duplicative event that led to the divergent 18S types preceded that of speciation within this group. These divergent 18S paralogues may have, or had, different functional pressures or rates of molecular evolution. Whether or not these divergent types are equally transcriptionally active throughout the life cycle, remain to be assessed.
Assuntos
Eletroforese em Gel de Poliacrilamida/métodos , Variação Genética , RNA Ribossômico 18S/química , Trypanosoma cruzi/classificação , Animais , Sequência de Bases , Fragmentação do DNA , Evolução Molecular , Temperatura Alta , Reação em Cadeia da Polimerase/métodos , Polimorfismo de Fragmento de Restrição , Homologia de Sequência do Ácido Nucleico , Trypanosoma cruzi/genéticaRESUMO
Triatomine bug species such as Microtriatoma trinidadensis, Eratyrus mucronatus, Belminus herreri, Panstrongylus lignarius, and Triatoma tibiamaculata are exquisitely adapted to specialist niches. This suggests a long evolutionary history, as well as the recent dramatic spread a few eclectic, domiciliated triatomine species. Virtually all species of the genus Rhodnius are primarily associated with palms. The genus Panstrongylus is predominantly associated with burrows and tree cavities and the genus Triatoma with terrestrial rocky habitats or rodent burrows. Two major sub-divisions have been defined within the species Trypanosoma cruzi, as T. cruzi 1 (Z1) and T. cruzi 2 (Z2). The affinities of a third group (Z3) are uncertain. Host and habitat associations lead us to propose that T. cruzi 1 (Z1) has evolved in an arboreal, palm tree habitat with the triatomine tribe Rhodniini, in association with the opossum Didelphis. Similarly we propose that T. cruzi (Z2) and Z3 evolved in a terrestrial habitat in burrows and in rocky locations with the triatomine tribe Triatomini, in association with edentates, and/or possibly ground dwelling marsupials. Both sub-divisions of T. cruzi may have been contemporary in South America up to 65 million years ago. Alternatively, T. cruzi 2 (Z2) may have evolved more recently from T. cruzi 1 (Z1) by host transfers into rodents, edentates, and primates. We have constructed a molecular phylogeny of haematophagous vectors, including triatomine bugs, which suggests that faecal transmission of trypanosomes may be the ancestral route. A molecular clock phylogeny suggests that Rhodnius and Triatoma diverged before the arrival, about 40 million years ago, of bats and rodents into South America.
Assuntos
Evolução Biológica , Ecossistema , Insetos Vetores/genética , Triatominae/genética , Trypanosoma cruzi/genética , Animais , Austrália , Doença de Chagas/transmissão , Reservatórios de Doenças , Genótipo , Interações Hospedeiro-Parasita , Comportamento de Nidação , Filogenia , Rhodnius/parasitologia , América do Sul , Triatominae/parasitologia , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
Extensive characterisation of Trypanosoma cruzi by isoenzyme phenotypes has separated the species into three principal zymodeme groups, Z1, Z2 and Z3, and into many individual zymodemes. There is marked diversity within Z2. A strong correlation has been demonstrated between the strain clusters determined by isoenzymes and those obtained using random amplified polymorphic DNA (RAPD) profiles. Polymorphisms in ribosomal RNA genes, in mini-exon genes, and microsatellite fingerprinting indicate the presence of at least two principal T. cruzi genetic lineages. Lineage 1 appears to correspond with Z2 and lineage 2 with Z1. Z1 (lineage 2) is associated with Didelphis. Z2 (lineage 1) may be associated with a primate host. Departures from Hardy-Weinberg equilibrium and linkage disequilibrium indicate that propagation of T. cruzi is predominantly clonal. Nevertheless, two studies show putative homozygotes and heterozygotes circulating sympatrically: the allozyme frequencies for phosphoglucomutase, and hybrid RAPD profiles suggest that genetic exchange may be a current phenomenon in some T. cruzi transmission cycles. We were able to isolate dual drug-resistant T. cruzi biological clones following copassage of putative parents carrying single episomal drug-resistant markers. A multiplex PCR confirmed that dual drug-resistant clones carried both episomal plasmids. Preliminary karyotype analysis suggests that recombination may not be confined to the extranuclear genome.
Assuntos
Animais , Variação Genética , Trypanosoma cruzi/genética , Resistência a Medicamentos , Marcadores Genéticos , Mamíferos , Gambás , Técnica de Amplificação ao Acaso de DNA PolimórficoRESUMO
Extensive characterisation of Trypanosoma cruzi by isoenzyme phenotypes has separated the species into three principal zymodeme groups, Z1, Z2 and Z3, and into many individual zymodemes. There is marked diversity within Z2. A strong correlation has been demonstrated between the strain clusters determined by isoenzymes and those obtained using random amplified polymorphic DNA (RAPD) profiles. Polymorphisms in ribosomal RNA genes, in mini-exon genes, and microsatellite fingerprinting indicate the presence of at least two principal T. cruzi genetic lineages. Lineage 1 appears to correspond with Z2 and lineage 2 with Z1. Z1 (lineage 2) is associated with Didelphis. Z2 (lineage 1) may be associated with a primate host. Departures from Hardy-Weinberg equilibrium and linkage disequilibrium indicate that propagation of T. cruzi is predominantly clonal. Nevertheless, two studies show putative homozygotes and heterozygotes circulating sympatrically: the allozyme frequencies for phosphoglucomutase, and hybrid RAPD profiles suggest that genetic exchange may be a current phenomenon in some T. cruzi transmission cycles. We were able to isolate dual drug-resistant T. cruzi biological clones following copassage of putative parents carrying single episomal drug-resistant markers. A multiplex PCR confirmed that dual drug-resistant clones carried both episomal plasmids. Preliminary karyotype analysis suggests that recombination may not be confined to the extranuclear genome.
Assuntos
Resistência a Medicamentos/genética , Variação Genética , Trypanosoma cruzi/genética , Animais , Antibacterianos/farmacologia , Marcadores Genéticos , Mamíferos , Neomicina/farmacologia , Gambás , Fosfotransferases (Aceptor do Grupo Álcool)/farmacologia , Técnica de Amplificação ao Acaso de DNA Polimórfico , Especificidade da Espécie , Transformação Genética , Trypanosoma cruzi/classificação , Trypanosoma cruzi/efeitos dos fármacosRESUMO
Buparvaquone (Butalex), a therapeutic for theileriosis, has been shown to have anti-leishmanial activity in vitro. Seven dogs with symptomatic, parasitologically positive, canine visceral leishmaniosis were treated with Butalex at 5 mg kg(-1) body weight using four doses over 12 days. Two animals showed minor clinical improvement (growth of healthy hair) but all remained parasitologically positive and disease progression was not halted.