Parasitology

Biography

Biography: Yuan Dong Mei

Abstract

Leishmaniasis are a complex range of diseases caused by infection with protozoan parasites of the genus Leishmania, which is still endemic in the west and northwest frontier regions of China. The previous phylogenetic studies based on COII, 18 S rRNA and 7SL RNA of Chinese Leishmania isolates indicate that the isolates from China may have had a more complex evolutionary history and an undescribed Leishmania species does exist in China. The Chinese representative isolates morphology were characterized and compared by cell and flagellum length, subpellicular microtubules counts using optical and electron microscopy. The Hsp 70 gene and cyt b gene sequences of Chinese isolates, two reliable markers for the species discrimination and phylogenetic analysis within the genus Leishmania were sequenced after PCR amplification. Then the sequences were aligned and the method of Bayesian inference was used for phylogenetic analysis. Through light microscopic observation, there existed differences among 5 Leishmania representatives from different foci of China in shape in the same period. Through electron microscopy, the promastigotes of 5 strains showed roughly identical intracellular structures except that the Golgi apparatus has not yet been observed in the isolate MHOM/ CN/90/SC10H2. 11 Hsp 70 sequences and 15 cyt b sequences were obtained in this study and then analyzed with 54 Hsp 70 sequences and 36 cyt b sequences retrieved from Genbank, respectively. Phylogenetic analysis indicated that Chinese Leishmania isolates occurred in four groups: L. donovani complex, L. tropica complex, L. major complex and Sauroleishmania. In conclusion, there are morphological differences among Leishmania isolates from different foci of China. The undescribed Leishmania sp. of China, which was most closely related to L. tarentolae belongs to Sauroleishmania. The ultrastructure characteristic of Leishmania sp. (MHOM/ CN/90/SC10H2) provides evidence to support it.