Browsing by Person "Hu, Junjie"

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A cyst-forming coccidian with large geographical range infecting forest and commensal rodents: Sarcocystis muricoelognathis sp. nov.
(2024) Qin, Tao; Ortega-Perez, Paula; Wibbelt, Gudrun; Lakim, Maklarin B.; Ginting, Sulaiman; Khoprasert, Yuvaluk; Wells, Konstans; Hu, Junjie; Jäkel, Thomas
Background: The geographic distribution and host-parasite interaction networks of Sarcocystis spp. in small mammals in eastern Asia remain incompletely known. Methods: Experimental infections, morphological and molecular characterizations were used for discrimination of a new Sarcocystis species isolated from colubrid snakes and small mammals collected in Thailand, Borneo and China. Results: We identified a new species, Sarcocystis muricoelognathis sp. nov., that features a relatively wide geographic distribution and infects both commensal and forest-inhabiting intermediate hosts. Sarcocystis sporocysts collected from rat snakes (Coelognathus radiatus, C. flavolineatus) in Thailand induced development of sarcocysts in experimental SD rats showing a type 10a cyst wall ultrastructure that was identical with those found in Rattus norvegicus from China and the forest rat Maxomys whiteheadi in Borneo. Its cystozoites had equal sizes in all intermediate hosts and locations, while sporocysts and cystozoites were distinct from other Sarcocystis species. Partial 28S rRNA sequences of S. muricoelognathis from M. whiteheadi were largely identical to those from R. norvegicus in China but distinct from newly sequenced Sarcocystis zuoi. The phylogeny of the nuclear 18S rRNA gene placed S. muricoelognathis within the so-called S. zuoi complex, including Sarcocystis attenuati, S. kani, S. scandentiborneensis and S. zuoi, while the latter clustered with the new species. However, the phylogeny of the ITS1-region confirmed the distinction between S. muricoelognathis and S. zuoi. Moreover, all three gene trees suggested that an isolate previously addressed as S. zuoi from Thailand (KU341120) is conspecific with S. muricoelognathis. Partial mitochondrial cox1 sequences of S. muricoelognathis were almost identical with those from other members of the group suggesting a shared, recent ancestry. Additionally, we isolated two partial 28S rRNA Sarcocystis sequences from Low’s squirrel Sundasciurus lowii that clustered with those of S. scandentiborneensis from treeshews. Conclusions: Our results provide strong evidence of broad geographic distributions of rodent-associated Sarcocystis and host shifts between commensal and forest small mammal species, even if the known host associations remain likely only snapshots of the true associations.
Morphological and molecular identification of sarcocystis arctica in captive cheetahs (Acinonyx jubatus) in China helps clarify phylogenetic relationships with Sarcocystis caninum and Sarcocystis felis
(2025) Liao, Zhe; Zhu, Niuping; Yang, Yurong; Deng, Shuangsheng; Jäkel, Thomas; Hu, Junjie; Salvarani, Felipe M.; Domingues, Sheyla Farhayldes Souza; Da Silveira, Júlia Angélica Gonçalves
To date, only one case is known where protozoan parasites of the genus Sarcocystis were found to infect cheetahs ( Acinonyx jubatus ); the cysts in the musculature were morphologically identified as S. felis . Here, we characterized sarcocysts by morphological and molecular methods that were observed in cheetahs who died in zoos in China. Only one type of sarcocyst was present in two of six cheetahs. By light microscopy, the sarcocyst wall was striated, 1.4–2.1 μm thick. Ultrastructurally, the wall had irregular-shaped, small villar protrusions, resembling wall type 9c, similar to those of S. arctica , S. caninum , and S. felis . The samples shared their highest molecular identity values with those of S. arctica and S. caninum : 99.9–100% and 99.8–100% (18S rRNA), 99.5% and 99.3–99.5% (28S rRNA), 95.9–97.5% and 96.3–97.3% (ITS-1), and 99.6% and 99.2–99.7% ( cox 1), respectively. Compared with ITS-1 of S. felis , identities ranged between 87.5% and 88.9%. Phylogenetic reconstruction revealed that the newly sequenced Sarcocystis clustered with S. arctica and S. caninum , whereas S. felis (ITS-1) and S. canis (ITS-1, 18S rRNA, cox 1) were sister species. Thus, we addressed the Sarcocystis species from the cheetahs as S. arctica , which is the first record of a Sarcocystis species believed to be specific for canids as intermediate hosts to infect a feline host.