Encystment/excystment response and serotypic variation in the gastropod parasite Tetrahymena rostrata (Ciliophora, Tetrahymenidae).
Parasitol Res
; 115(2): 771-7, 2016 Feb.
Article
em En
| MEDLINE
| ID: mdl-26499199
ABSTRACT
Tetrahymena rostrata, which is characterized by a particular encystment-excystment cycle involving autogamy, has been recently found infecting the kidney of edible Helix aspersa snails under farming conditions. In this work, the effects of several factors on its encystment/excystment behaviour and the occurrence of different serotypes were investigated. The encystment/excystment response under starvation conditions was seriously affected by temperature. While a peak of encystment at 48 h followed by a progressive spontaneous excystment was observed at 18 and 25 °C, the encystment response was practically inhibited at 5 °C and clearly slowed down at 10 °C. At 30 °C, most of surviving ciliates remained encysted throughout the experiment, with spontaneous excystment being detected only after switching the temperature to 18 °C. Soil components also affected the encystment/excystment behaviour at 18 °C, with spontaneous excystment occurring in the presence of a sterile-filtered soil extract or mineral water but being strongly minimized with a non-filtered soil extract. Resting cysts formed in the latter extract exhibited a 34 times thicker and ultrastructurally more complex wall than that formed in mineral water and retained the excystment ability for about 4 weeks. Incomplete desiccation did not affect significantly the encystment response, while the mucus and kidney extracts from snails as well as a ciliate extract strongly stimulated a rapid excystment. Finally, two different serotypes infecting H. aspersa in heliciculture farms of Galicia (NW Spain) were identified, but no differences were observed between the encystment/excystment responses exhibited by two isolates belonging to each serotype.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tetrahymena
/
Caracois Helix
Tipo de estudo:
Prognostic_studies
Limite:
Animals
País/Região como assunto:
Europa
Idioma:
En
Revista:
Parasitol Res
Assunto da revista:
PARASITOLOGIA
Ano de publicação:
2016
Tipo de documento:
Article