作者机构:
[Yi, J. N.; Li, Z. B.; Jin, Y. C.; Li, F.; Liu, J. H.; Cheng, T. Y.] Hunan Agr Univ, Coll Vet Med, Hunan Prov Key Lab Prot Engn Anim Vaccines, Changsha 410128, Hunan, Peoples R China.;[Li, F.; Liu, J. H.; Cheng, T. Y.] Hunan Coinnovat Ctr Anim Prod Safety, Changsha 410128, Hunan, Peoples R China.
通讯机构:
[Cheng, T. Y.] H;Hunan Agr Univ, Coll Vet Med, Hunan Prov Key Lab Prot Engn Anim Vaccines, Changsha 410128, Hunan, Peoples R China.;Hunan Coinnovat Ctr Anim Prod Safety, Changsha 410128, Hunan, Peoples R China.
摘要:
The cattle tick, Rhipicephalus microplus (formerly Boophi/us microp lus), is the most important blood-feeding ectoparasite of cattle in tropical and subtropical regions of the world. In this study, we examined sequence variability in three mitochondrial (mt) DNA (cox1, nad1, nad4) among cattle tick R. microplus originating from four provinces of China. A portion of earl (pcox1), nad1 (pnad1) and nad4 (pnad4) genes were amplified by polymerase chain reaction (PCR) separately from adult R. microplus individuals and the amplicons were subjected to sequence from both directions. The sequence of mt cox1, nad1, nad4 genes was 817 bp, 350 bp, and 794 bp in size, respectively. The intraspecific sequence variations within R. microplus were 0-8.6% for coxl, 0-4.9% for nad1 and 0-10.3% for nad4. However, the interspecific sequence differences among the members of the Rhipicephalus [R. sanguineus (JX416325) and R. turanicus (NC035946)] were significantly higher, being 16.9-20.5%, 18-22.8%, 22.8-25.3% for pcox1, pnad1 and pnad4, respectively. In addition, genetic differences were 7.9-8.6% for cox1, 4.3-4.9% for nad1 and 10-10.3% for nad4 between the two detected lineages (R. microplus clade A and clade B). Phylogenetic analyses indicated that all the Rhipicephalus isolates from the present study represents R. microplus, supporting that R. microplus represents species complex. Our result provided an additional genetic evidence for the existence of species complex within R. microplus in China.
摘要:
Toxascaris leonina is one of the most common intestinal parasites of canids and felids. In this study, we characterised the entire mitochondrial (mt) genome sequence of T. leonina from the cheetah and compared it with that of T. leonina from the dog. The entire mt genome sequence of T. leonina from the cheetah is 14,685 bp in size, which is 375 bp longer than that from the dog, and it is 408 bp longer than that from the South China tiger. The overall nucleotide sequence (except for the non-coding region) identity was 92.8% between the two mt genomes of T. leonina from the cheetah and the dog. For the 12 protein-coding genes, sequence difference between T. leonina from the cheetah and the dog was 5.0–9.7% at the nucleotide level and 1.0–7.2% at the amino acid level. Moreover, comparison of mt cox1 sequences among T. leonina isolates (n = 23) from different hosts revealed substantial nucleotide differences (10.6%). Phylogenetic analysis showed the separation of T. leonina from canid and felid hosts into three distinct clades. Taken together, these mtDNA datasets indicate that T. leonina from canid and felid hosts represents a species complex. Our results have implications for further studies of the molecular epidemiology, systematics and population genetics of this nematode.