Ascaris suum is an important parasite of pigs that causes tremendous economic losses globally to agriculture and animal husbandry annually. RNA interference (RNAi) technology has been described as a successful and useful approach for the elucidation of gene function in parasitic nematodes. In the present study, RNAi was used to silence the expression of a gene encoding enolase in A. suum by soaking infective larvae in double-stranded RNA derived from an EST (representing As-enol-1) selected from an A. suum infective larvae-specific cDNA library. The mRNA levels of RNAi-treated larvae were examined by Reverse-Transcription PCR (RT-PCR) analysis. The survival of RNAi-treated larvae was compared with larvae treated with dsRNA-free culture medium. The effect of enolase depletion on the development of A. suum larvae was assessed by infecting BALB/c mice with RNAi-treated larvae. The results showed that enolase gene expression was silenced completely and the survival rate of the RNAi-treated nematodes was reduced by 20.11% (P<0.01) after soaking for 72 h. Although no significant difference was detected in the numbers of larvae recovered from the liver and lungs of infected mice 4 days post infection, RNAi knockdown of the A. suum enolase mRNA led to significant shorter larvae, indicating that loss of enolase expression may cause delays in larval development.
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