关键词: 大瓶螺, PCR, cDNA, 广州管圆线虫, 幼虫

Abstract: Objective To establish a PCR assay for detecting the third-stage larvae of Angiostrongylus cantonensis in Pomacea canaliculata. Methods Polymerase chain reaction primers were designed by the software Lasergene， based on the specific cDNA of the third-stage larvae of A.cantonensis in Genbank. The total RNA was prepared from the third-stage larvae of A.cantonensis and of the snails by TRIzol one-step protocol. Amplification by RT-PCR was carried out following the kit protocol. Results RT-PCR assay revealed a clear differentiation between infected and negative snails. When a mixture of the total RNA from the negative snails and the third-stage larvae of A.cantonensis was tested by the PCR assay， the detectable level was 128 pg RNA， a concentration close to one third-stage larva of A.cantonensis， mini-mum concentration that could be found by naked eyes. The minimum detected total RNA concentration of the third-stage larvae of A.cantonensis was 105 pg by PCR assay. Conclusion A PCR assay has been developed for detecting A.cantonensis larva in Pomacea canaliculata.

Key words: Pomacea canaliculata, PCR, cDNA, Angiostrongylus cantonensis, Larva