identification and characterization of a differentially expressed gene (07e12) in the infective larvae of the parasitic nematode ascaris suum.

background: parasitic nematodes cause animal and human diseases of major socio-economic importance worldwide. the suppression of parasite development at particular developmental stages could provide an alternative approach for nema-tode control. in this study, ascaris suum was used as a model system in the study of the differentially expressed genes in the infective l3 stage. methods: the gene (07e12) was screened and identified from the subtractive cdna library for the infective larvae of ascaris suum using real-time quantitative pcr. then, the full-length cdna of 07e12 was characterized by 3′ and 5′ rapid amplification of cdna ends (race). the characteristics of the gene were further analyzed using bioinformatic analyses. results: the results showed that the gene 07e12 was differentially expressed in the third-stage larvae of a. suum and its expression level in the infective larvae was much higher than in other stages. it was shown that the gene 07e12 had 99% iden-tity with the corresponding sequences of the a. suum whole genome shotgun se-quence containing the homologous sequences with conserved sequences of neu-ropeptide-like protein family member. likewise, by performing blastn and blastp searches in the genbank™, it was shown that this gene had 99 % identity with a. suum cre-nlp-2 protein. conclusion: this gene 07e12 which is differentially expressed in the third-stage larvae of a. suum may encode a neuropeptide-like protein family member, a very important molecule in the process of infecting a host.