[A comparative study on isoenzymes of Sarcocystis spp. from cattle and water buffaloes].

OBJECTIVE: To analyze the zymogram of peroxidase (PER) and phosphoglucose isomerase (PGI) of three species of Sarcocystis. METHODS: The collected parasites were homogenized and fragmented by ultrasonication. After centrifugation, the supernatants were analyzed by isoelectric focusing electrophoresis. RESULTS: The isolates of S. cruzi from infected water buffalo and cattle all showed identical enzyme profiles, 7 bands of PER at pH 4.44-6.98 and 6 bands of PGI at pH 4.66-6.53; and same with the isolates of S. hirsuta. 5 bands of PER at pH 4.97-7.15 and 4 bands of PGI at pH 4.70-6.51. The zymograms among S. cruzi, S. hirsuta and S. fusiformis were different considerably. CONCLUSION: The data support the hypothesis that both water buffalo and cattle are the natural intermediate hosts of S. cruzi and S. hirsuta at the gene level. S. cruzi, S. hirsuta and S. fusiformis are different species.

[Screening serum response special antibodies of U251 cell line from surface display phage antibody library].

U251 cell is a sensitive cell line to serum, which stops at G0 phase of cell cycle in no-serum medium, and recovers growth when the serum is added into no-serum medium. The cell can express corresponding proteins in different phase of cell cycle. Therefore it is very signification for the study of cell cycle regulation mechanism that explores these proteins. In this paper, the mouse antibody phage display library was added into the bottle in which the serum starvation U251 cells had been cultured, and the special antibody phages were absorbed. Then the absorbed antibody phages were amplified by adding E. coli TG1 and helper phage M13K07. Amplified antibody phages were added into bottle in which the serum cultured cell after serum starvation (follow named as serum recovered cells) were incubated, so that the cell absorbed the no-special antibody phages for the serum starvation cell and the special antibody phages were in supernatant. The remaining no-special antibody phages in the supernatant were discarded by repeating above program 3-4 times. The pure special antibody phages were gotten, and amplified by adding the host cell E. coli TG1 and helper phage M13K07. Then the host bacterium infected special antibody phage was spread on the plate medium with ampicillin, and the monoclonal antibody phages were gotten. Using same as above program, the monoclonal antibody phages absorbed specially for serum recovered U251 cells were obtained when the serum recovered cells instead of serum starvation cells and serum starvation cells instead of serum recovered cells. In this study, ninety-six positive monoclonal antibody phages that absorbed specially the serum starvation cells and eighty-two positive monoclonal antibody phages that absorbed specially the serum recovered cells were obtained. By using cell immunochemistry assay, two special signification antibodies were obtained. one (No.11) was the strong response in serum starvation cells, the other (No.2) was the strong response in serum recovered cells. The antibody No.2 had the distinctive response to the serum recovered cells in different incubation time (15min, 30min, 1h, 2h, 4h, 8h, 12h and 48h) after serum starvation. The results showed that No.2 antibody would be useful to research the factors of cell cycle regulation and apply to tumor diagnosis.