RESUMO
Pontoporia blainvillei (Gervais and d'Orbigny, 1844) is an endangered small cetacean endemic to South America with four Franciscana Management Areas (FMA) recognized as different population stocks. The role of the intestinal parasite Synthesium pontoporiae (Digenea: Brachycladiidae) as a possible biological marker to differentiate P. blainvillei stocks was evaluated using nuclear and mitochondrial DNA markers. Internal transcribed sequence 1 and 2 (ITS1 and ITS2) regions of S. pontoporiae did not show intraspecific variability. The mitochondrial NADH dehydrogenase subunit 3 (ND3) and cytochrome oxidase subunit I (COI) gene sequences suggested lack of population structure in S. pontoporiae and population expansion. The apparent panmixia of S. pontoporiae may be due to the high mobility of one or more of its intermediary hosts. Alternatively, it may be due to the small sample size. This result is incongruent with the previously proposed FMA.
Assuntos
Infecções por Cestoides/veterinária , Golfinhos/parasitologia , Variação Genética , Enteropatias Parasitárias/veterinária , Platelmintos/genética , Platelmintos/isolamento & purificação , Animais , Argentina , Brasil , Infecções por Cestoides/epidemiologia , Infecções por Cestoides/parasitologia , Complexo IV da Cadeia de Transporte de Elétrons/genética , Espécies em Perigo de Extinção , Proteínas de Helminto/genética , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Dados de Sequência Molecular , NADH Desidrogenase/genética , Filogenia , Platelmintos/classificação , Platelmintos/enzimologiaRESUMO
BACKGROUND AND AIMS: Haematoloechus, digeneans parasites of amphibians, is a species-rich genus with more than 50 species around the globe. Establishing an accurate taxonomy for this group has been difficult due to high intraspecific variability. Nuclear DNA sequences have given independent information about species validity and phylogeny of the group. MATERIALS AND METHODS: In this paper, I test the performance of partial sequences of the mitochondrial cytochrome c oxidase subunit I (cox1) gene in the differentiation of recognized species of the genus and in the detection of potential new taxa. Samples from 13 nominal species were sequenced, plus four samples that could not be assigned to any described species based on morphology. RESULTS: Parsimony analysis of the amplified 360 bp fragment resulted in six most parsimonious trees showing the same grouping of samples, differing in the samples' arrangement within those groups. All 13 species were recovered on the trees, and five potential new species are shown. CONCLUSION: Additional sampling and sequencing is necessary to support this hypothesis, but with this preliminary information the search for diagnostic characters that allow the description of the new taxa is less difficult.
Assuntos
DNA de Helmintos/genética , DNA Mitocondrial/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Proteínas de Helminto/genética , Platelmintos/classificação , Platelmintos/genética , Anfíbios/parasitologia , Animais , Sequência de Bases , Primers do DNA/genética , Evolução Molecular , Genes de Helmintos , Genes Mitocondriais , México , Dados de Sequência Molecular , Filogenia , Platelmintos/enzimologia , Especificidade da EspécieRESUMO
The thioredoxin and glutathione systems play a central role in thiol-disulfide redox homeostasis in many organisms by providing electrons to essential enzymes, and defence against oxidative stress. These systems have recently been characterized in platyhelminth parasites, and the emerging biochemical scenario is the existence of linked processes with the enzyme thioredoxin glutathione reductase supplying reducing equivalents to both pathways. In contrast to their hosts, conventional thioredoxin reductase and glutathione reductase enzymes appear to be absent. Analysis of published data and expressed-sequence tag databases indicates the presence of linked thioredoxin-glutathione systems in the cytosolic and mitochondrial compartments of these parasites.