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The present study examined sequence variations in three mitochondrial DNA (mtDNA) regions, namely, NADH dehydrogenase subunit 5 ( nad5), adenosine triphosphate subunit 6 ( atp6) and cytochrome c oxidase subunit 3 ( cox3), among Oesophagostomum asperum isolates from different regions in Shaanxi and Hunan provinces, China. The lengths for partial sequences of nad5 (p nad5), atp6 (p atp6) and cox3 (p cox3) were 427 bp, 381 bp and 337 bp, respectively. The intra-specific sequence variations among all O. asperum samples were 0-2.11%, 0-1.84% and 0-1.48% for p nad5, p atp6 and p cox3, respectively, while the inter-specific sequence differences among Oesophagostomum species in pig and small ruminants were 18-21.3% for p nad5, 18.3-24.5% for p atp6 and 10.6-13.7% for p cox3. A phylogenetic analysis based on combined sequences of three mtDNA fragments indicated that all O. asperum isolates were grouped in one solid clade, and the Oesophagostomum spp. from pig were located in another clade. However, these mtDNA fragments could not reveal genetic relationships of geographical isolates of O. asperum in China. These results provided valuable information for studying population genetics of Oesophagostomum spp., and for controlling Oesophagostomum infection in animals as well as humans. [ABSTRACT FROM AUTHOR]

The present study examined the variations in three mitochondrial (mt) DNA sequences, namely cytochrome b ( cytb), cytochrome c oxidase subunit 3 ( cox3) and NADH dehydrogenase subunit 5 ( nad5), among Baylisascaris schroederi isolates from the Qinling subspecies of the giant panda in Shaanxi province, northwestern China. No differences in length were detected in the three mt fragments from different isolates. The intra-specific sequence variations within all B. schroederi samples were 0-2.6% for p cytb, 0-1.8% for p cox3 and 0-2.1% for p nad5, while the inter-specific sequence differences among members of the genus Baylisascaris were 8.2-15.2%, 6.2-15.9% and 8.4-16.0% for p cytb, p cox3, p nad5, respectively. A phylogenetic analysis of the combined sequences of p cytb, p cox3 and p nad 5 showed that all B. schroederi samples in the present study were located in two large clusters, with one cluster containing samples from giant pandas in Sichuan province. These findings provide basic information for further study of molecular epidemiology and control of B. schroederi infection in the Qinling subspecies of the giant panda and throughout China. [ABSTRACT FROM AUTHOR]

The genetic variations in three mitochondrial DNA (mtDNA) regions, namely portion of cytochrome c oxidase subunit 1 (p cox1), NADH dehydrogenase subunit 1 (p nad1) and cytochrome b (p cytb), were examined for Dicrocoelium dendriticum samples isolated from different origins in Shaanxi Province, northwestern China. The intra-specific sequence differences within D. dendriticum samples were 0-0.52% for p cox1, 0-0.73% for p nad1 and 0-0.58% for p cytb. Phylogenetic analyses based on combined sequences of three mtDNA showed that all D. dendriticum samples were clustered together in same clade of Paragonimus westermani. But the phylogenetic trees could not reveal geographically genetic relationships of D. dendriticum isolates in this province. These findings will provide basic information for further study of molecular epidemiology and control of D. dendriticum infection in this province as well as in China. [ABSTRACT FROM AUTHOR]