在大豆夜蛾多核型多角体病毒培养过程中，缺少胎牛血清的影响

Cells growing with 1% FBS or 10% FBS during 48 h were studied by flow cytometer experiments in order to obtain a quantitative determination of cell stage subpopulations. The analysis of in vitro cell cultures in active replication state can be achieved by nucleic acid fluorescence labeling and then analyzing the fluorescence properties of each cell in the whole population. Quiescent and G1 cells have one unit of nuclear genome and will therefore have 1× fluorescence intensity. On the other hand, cells in phase G2/M have two units of nuclear genome and thus have a 2× fluorescence intensity; whereas S phase cells, that are synthesizing DNA, have values of fluorescence intensity intermediate between 1× and 2× (Figure 2). According to this, it was found that after carrying out the deprivation process with 1% FBS in GRACE's medium during 48 h 90% of UFL-Ag-286 cells were in G0/G1, 3% in S, and 7% in G2/M, yielding similar results than those obtained in mammal cells [25–27]. Meanwhile, actively growing cells showed only 69% of the population in G0/G1, 6% in S and 25% in G2/M.

Figure 2

Subpopulations of UFL-Ag-286 cells. Monolayers of UFL-Ag-286 cells were treated during 48 h both in standard condition (10% FBS) and synchronized condition (1% FBS) in GRACE's medium, harvested and stained with ethidium bromide, and analyzed by flow cytometer. The bar graph shows the results corresponding to the subpopulation cells according to typical stages (G2/M, S and G0/G1) based on DNA content measures.