ABSTRACT
This paper explored the acute response of Paramecium caudatum to the stress of tetracycline (TC) and tetracycline hydrochloride (HTC).The half-lethal concentration (LC50), the half-inhibitory concentration (EC50), and the lowest-observed-effect concentration (LOEC) were determined, and the changes of the monoclonal growth curve stressed by the half-inhibitory concentration (EC50) antibiotics were observed. The results showed that the values of 24h-LOEC and 24h-LC50 of TC were a little higher than HTC, but the 24h-EC50 was a little lower than HTC. The response of the enzyme activity of superoxide dismutase(SOD), peroxidase (POD), catalase (CAT) to 24h-EC50 indicated that TC and HTC have a strong inhibitory effect on SOD enzyme activity, but a weak inhibitory effect on CAT and POD enzyme activity. The changes in the monoclonal growth curve of P. caudatum suggested that TC and HTC significantly inhibited the division and reproduction of P. caudatum. This research provided a basis for assessing the environmental risk of tetracycline antibiotics as well as a reference for the scientific and rational use of antibiotics.
