English to French Tech/Engineering Biology (-tech,-chem,micro-) culture bactérienne

Based on the results of a preliminary study, a dose-finding study was performed up to 35000 µgTOS/plate (lactase activity: 5,935 U/plate), which was the upper-limited dose that could be made from the stock solution. As a result, the number of revertant colonies increased 2 times or more that in the negative control in strains TA98 and TA1537 in the -S9 assay and TA1535 and TA98 in the +S9 assay. However, the acceleration of growth of background bacteria with a cloudy medium was observed at higher doses in both assays. It is well known that the similar phenomenon is often observed in the case of using a substance containing free amino acids