Optimal inoculation ratios of Toxoplasma gondii VEG tachyzoites to their host cells using curve regression methods
GUO Hai-ting1, TAN Jie1, XIA Chun-bo1, RONG Cui-ping1, ZOU Zhen-you1, LI Zhong-yuan1,2
1. Guangxi Key Laboratory of Brain and Cognitive Neuroscience, College of Basic Medicine, Guilin Medical University, Guilin 541199, China; 2. College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China
Abstract:To investigate the effect of different gradients of Toxoplasma gondii tachyzoites to the growth of their host cells in vitro and their inoculation ratios, Vero cells were spread into 96-, 24-, 12-, and 6-well plates or 25 T bottles according to the recommended volumes were cultivated for 12 hours at 37 ℃ in the air containing 5% CO2. The purified tachyzoites of T. gondii VEG strain were counted and diluted into eight gradients with the serial two-fold method, and were used to infect the cells above, guaranteeing the number of parasites in the first well or bottle were equal to the host cells. After cultivation for 4 days, the products were collected and used to extract DNA for the Real-time PCR detections. According to the obtained number of T. gondii (n=3), seven kinds of curves were matched based on the common regression models to determine the best type of function which belong to, and their extremum values were calculated to confirm the inoculation ratios between the parasite and its host cells. The results of Real-time PCR showed that the ability of T. gondii VEG strain for eroding its host cells were relevant to the incipient infection amount of this parasite and the specification of consumables. In addition, we found that the quartic polynomial function was the best regression equation for the 4 day-cultivated tachyzoites, and the optimal inoculation ratios between the parasite and its host cells, that is, 1/7.20 for 96-, 1/5.32 for 24-, 1/4.53 for 12-, and 1/4.03 for 6-well plate or 1/43.02 for 25 T bottle, were finally obtained in this study via calculating the second derivative and extremum of these equations.
郭海婷, 谭洁, 夏春波, 荣翠平, 邹珍友, 李中原. 刚地弓形虫VEG株速殖子感染宿主细胞最优接种比的曲线拟合分析[J]. 中国人兽共患病学报, 2020, 36(2): 105-109.
GUO Hai-ting, TAN Jie, XIA Chun-bo, RONG Cui-ping, ZOU Zhen-you, LI Zhong-yuan. Optimal inoculation ratios of Toxoplasma gondii VEG tachyzoites to their host cells using curve regression methods. Chinese Journal of Zoonoses, 2020, 36(2): 105-109.