RESUMO
PCR-based molecular tools are widely used for the identification and characterization of protozoa. Here we report the molecular analysis of Eimeria species using combined methods of whole genome amplification (WGA) and nested PCR. Single oocyst of Eimeria stiedai or Eimeriamedia was directly used for random amplification of the genomic DNA with either primer extension preamplification (PEP) or multiple displacement amplification (MDA), and then the WGA product was used as template in nested PCR with species-specific primers for ITS-1, 18S rDNA and 23S rDNA of E. stiedai and E. media. WGA-based PCR was successful for the amplification of these genes from single oocyst. For the species identification of single oocyst isolated from mixed E. stiedai or E. media, the results from WGA-based PCR were exactly in accordance with those from morphological identification, suggesting the availability of this method in molecular analysis of eimerian parasites at the single oocyst level. WGA-based PCR method can also be applied for the identification and genetic characterization of other protists.
Assuntos
DNA de Protozoário/genética , Eimeria/genética , Estudo de Associação Genômica Ampla/métodos , Reação em Cadeia da Polimerase , Animais , Coccidiose/parasitologia , Coccidiose/veterinária , DNA Intergênico/genética , DNA de Protozoário/isolamento & purificação , DNA Ribossômico/genética , DNA Ribossômico/isolamento & purificação , Eimeria/classificação , Eimeria/isolamento & purificação , Gado , Oocistos/classificação , Aves Domésticas , RNA Ribossômico 18S/genética , RNA Ribossômico 23S/genética , CoelhosRESUMO
CD8(+) T cells play a major role in the immune protection of host against the reinfection of Eimeria maxima, the most immunogenic species of eimerian parasites in chickens. To explore the dominant complementarity-determining regions 3 (CDR3) of CD8(+) T cell populations induced by the infection of this parasite, sequence analysis was performed in this study for CDR3 of CD8(+) T cells from E. maxima infected chickens. After 5 days post the third or forth infection, intraepithelial lymphocytes were isolated from the jejunum of bird. CD3(+)CD8(+) T cells were sorted and subjected to total RNA isolation and cDNA preparation. PCR amplification and cloning of the loci between Vß1 and Cß was conducted for the subsequent sequencing of CDR3 of T cell receptor (TCR). After the forth infection, 2 birds exhibited two same frequent TCR CDR3 sequences, i.e., AKQDWGTGGYSNMI and AGRVLNIQY; while the third bird showed two different frequent TCR CDR3 sequences, AKQGARGHTPLN and AKQDIEVRGPNTPLN. No frequent CDR3 sequence was detected from uninfected birds, though AGRVLNIQY was also found in two uninfected birds. Our result preliminarily demonstrates that frequent CDR3 sequences may exist in E. maxima immunized chickens, encouraging the mining of the immunodominant CD8(+) T cells against E. maxima infection.