RESUMO
Biomphalaria peregrina was found to be naturally infected with cercariae of Zygocotyle lunata in a pond of the Zoological Garden of Buenos Aires. Mice and chicks were fed metacercariae and gravid adults recovered. Eggs recovered from mice feces were used for experimental infections. Laboratory-reared B. peregrina and 4 other Biomphaluria spp. were successfully infected with Z. lunata miracidia. Biomphaleria glabrata was refractory. Species of Helisoma, the only intermediate hosts of Z. lunata so far reported, have never been found in Argentina. Species of Biomphalaria may be intermediate hosts of Z lunata in the southern region of the Parana River Basin.
Assuntos
Biomphalaria/parasitologia , Doenças das Aves/transmissão , Vetores de Doenças , Paramphistomatidae/fisiologia , Infecções por Trematódeos/veterinária , Animais , Argentina , Doenças das Aves/parasitologia , Aves , Galinhas , Camundongos , Infecções por Trematódeos/parasitologia , Infecções por Trematódeos/transmissãoRESUMO
The correct identification of Biomphalaria oligoza, B. orbignyi and B. peregrina species is difficult due to the morphological similarities among them. B. peregrina is widely distributed in South America and is considered a potential intermediate host of Schistosoma mansoni. We have reported the use of the polymerase chain reaction and restriction fragment length polymorphism analysis of the internal transcribed spacer region of the ribosomal DNA for the molecular identification of these snails. The snails were obtained from different localities of Argentina, Brazil and Uruguay. The restriction patterns obtained with MvaI enzyme presented the best profile to identify the three species. The profiles obtained with all enzymes were used to estimate genetic similarities among B. oligoza, B. peregrina and B. orbignyi. This is also the first report of B. orbignyi in Uruguay.
Assuntos
Biomphalaria/genética , Insetos Vetores/genética , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , RNA Ribossômico/genética , Animais , Biomphalaria/classificação , Eletroforese em Gel de Poliacrilamida , Insetos Vetores/classificação , Coloração pela PrataRESUMO
The intermediate hosts of S. mansoni in South America, B. glabrata, B. tenagophila, and B. straminea, were identified by restriction fragment length polymorphism (RFLP) analysis of the internal transcribed spacer region of the rRNA gene. The restriction patterns obtained with DdeI were the most informative of the eight enzymes that were tried. The RFLP profiles obtained using this enzyme are highly distinctive and exhibit low levels of intraspecific polymorphism even between specimens collected from diverse regions of Brazil, Argentine, Paraguay, and Uruguay. The method proved useful for the identification of DNA extracted from eggs, permitting species identification while preserving the living adult specimens for further studies.
Assuntos
Biomphalaria/classificação , DNA Ribossômico/análise , RNA Ribossômico/genética , Schistosoma mansoni/fisiologia , Animais , Biomphalaria/genética , Biomphalaria/parasitologia , Brasil , DNA Ribossômico/química , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Reprodutibilidade dos Testes , Mapeamento por RestriçãoRESUMO
Studies based on shell or reproductive organ morphology and genetic considerations suggest extensive intraspecific variation in Biomphalaria snails. The high variability at the morphological and genetic levels, as well as the small size of some specimens and similarities between species complicate the correct identification of these snails. Here we review our work using methods based on polymerase chain reaction (PCR) amplification for analysis of genetic variation and identification of Biomphalaria snails from Brazil, Argentina, Uruguay and Paraguay. Arbitrarily primed-PCR revealed that the genome of B. glabrata exhibits a remarkable degree of intraspecific polymorphism. Low stringency-PCR using primers for 18S rRNA permitted the identification of B. glabrata, B. tenagophila and B. occidentalis. The study of individuals obtained from geographically distinct populations exhibits significant intraspecific DNA polymorphism, however, specimens from the same species, exhibit some species specific LSPs. We also showed that PCR-restriction fragment of length polymorphism of the internal transcribed spacer region of Biomphalaria rDNA, using Ddel permits the differentiation of the three intermediate hosts of Schistosoma mansoni. the molecular biological techniques used in our studies are very useful for the generation of new knowledge concerning the systematics and population genetics of Biomphalaria snails.