[An efficient and accurate method for counting target molecules in phage-display peptide library].

The phage titer of samples representing the low, intermediate and high phage number was respectively determined by the double-layer agar plate (DLAP) method and real-time PCR assay. The two methods accurately measured the titer of samples. The plaques from about 1/3 double-agar layer plates could be used to determine the phage titer. The DLAP experiment should repeat 10 times with 10 microl sample each time, while the within-assay coefficient variation (CV) was 4.93%-30.38%. At the same time, the real-time PCR assay only repeated 3 times with 1 microl phage each time, while CV for within-assay ranged from 0.02% to 0.25%. Results indicated that real-time PCR is a simple and quick method for determining bacteriophage titer.

[Biological identification on sub-cultivation cells of Schistosoma japonicum adult worms in vitro].

Cultivation of cells from 30-day old Schistosoma japonicum (S.j) adult worms showed that the growth features of the cells were semi-floating and accumulative. The survival rate of the primary cells, passage cells prior to the 5th generation and recovered cells was all up to 90%. Phases of cell division were observed during cultivation. Chromosome karyotype of the 5th generation cells possessed diploid feature of the blood-flukes (2n=8 in number). Ultrastructure of the 5th generation cells showed that four types of cells in normal morphology and three types of cells in abnormal morphology were both viewed. It is suggested that some of the cells from S.j adult worms were subcultured successfuly in the 1640-40 defined medium.