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Objective: To identify the protein from host macrophages which interacted with GRA7 dense granule protein of Toxoplasma gondii, and reveal the relationship between protein interaction and infection process., Methods: The recombinant GRA7 protein with N-terminal GST tag were used as a bait in in vitro GST Pull-down experiment, the proteins of THP-1 monocytic macrophage cell line were captured and identified by LC-MS/MS proteomics method. The in vivo protein interaction was verified by Co-IP experiment The overexpression of the target host protein by pcDNA3.1 (+) vector in THP-1 macrophage was further used to analyze the relationship between protein interaction and infection process., Results: The captured THP-1 cell protein was about Mr 29000, which was identified as human carbonic anhydrase 1 (hCA1). The significant in vivo protein-protein interaction between GRA7 and hCA1 was verified by Co-IP assay. The overexpression of hCA1 gene in THP-1 macrophage induced a higher propagation speed of Tgondii and the formation of the parasitophorous vacuole, but did nmt influence the number of the parasite., Conclusion: There is a significant protein interaction between Toxoplasma GRA7 dense granule protein and hCA1 enzyme from host macrophages, which is positively related with the propagation speed of T. gondii.

Objective: To separate and identify the surface proteins and secreted proteins of Toxoplasma gondii tachyzoites of RH strain., Methods: T. gondii tachyzoites were cultured in Vero cells, and purified by filtration and Percoll cell separation solution. The biotin-labeled tachyzoites were lysed, and the surface and secreted proteins were separated by NeutrAvidin agarose beads. After condensation and SDS-PAGE, the protein were collected, digested and identified by LC/MS-MS., Results: A total of 785 T. gondii proteins were identified, 81 (10.3%) of which were originally annotated as the surface or secreted proteins. Among the highly-expressed (PSM>10) 65 proteins, 43 (66%) were originally annotated as surface or secreted proteins, while the others were predicted unknown proteins., Conclusion: The surface and secreted proteins of T. gondii are separated by biotin labeling and avidin chromatography, among which some potential new surface or secreted proteins of T. gondii are identified.

Objective: To establish axenic cultivation of Pneumocystis carinii (P.c)., Methods: The organisms of P.c were isolated from the bronchoalveolar lavage fluid (BALF) of the rats with Pneumocystis carinii pneumonia (PCP) and cultured in a medium which was based on IMDM(GIBCO) supplemented with S-adenosyl-L-methionine, putrescine, N-acetyl glucosamine, putrescine, L-cysteine and L-glutamine, and newborn calf serum. The organisms cultured in the system were identified by observing the morphology of cysts in smears stained with Gomori's methenamine silver nitrate stain (GMS). Ultrastructure of the cysts/trophozoites was examined by transmission electron microscopy. The sequences of mitochondrial large ribosomal DNA subunit of the cultured organisms were compared with the Pneumocystis carinii f.sp. ratti variant isolate (GenBank No U20173) and Pneumocystis carinii f.sp.hominis (GenBank No M58605)., Results: Five isolates of P. carinii received from BALF of 8 rats with PCP were cultured axenically and continuously in the system. The cultured organisms could be stored in frozen condition and used to reinitiate culture, and were amplified by 19-22 times within 72 h. The morphology, ultrastructure and gene sequencing of the cultured organisms confirmed that the isolated organisms were P. carinii., Conclusion: Five continuously and axenicly cultured isolates of P. carinii have been received.