Physiological Toxicity Of Pentadecafluorooctanoic Acid On Saccharomyces Cerevisiae

Pentadecafluorooctanoic acid (PFOA), a chemical that is widely used in industries because of its strong chemical stability and good hydrophobic oleophobic, is one of the most typical perfluorinated compounds in the environment and is also a transformation product of many kinds of fluorine compounds in the environment. Because of widely detected in the environment, people paid more and more attention about the environmental impact and the risk of human health of PFOA.In order to explore the physiological toxicity of PFOA on Saccharomyces cerevisiae, the cell growth of Saccharomyces cerevisiae were measured by FCM and the cell membrane fatty acids content was determined by GC/MS under the stress of PFOA. The research results are as follows:(1) The growth of Saccharomyces cerevisiae was inhibited under the stress of PFOA, the growth inhibition was positively correlated with the concentration of PFOA. The DRC of PFOA and time inhibition curve of PFOA were fit by the function of Weibull and Polynomial function fitting.The function expression of DRC is:E=1-exp{-exp[0.09+6.051og10 (c)]}, R2 is 0.9917, EC50=162.34 mg·L-1.The function expression of Time response curve is:E=-4.60×10-6 Xt4+9.84×10-4 Xt3-0.07Xt2+2.51 Xt+6.05,R2 is 0.9923.(2) PFOA of 100 mg·L-1 had acute toxicity to Saccharomyces cerevisiae, and that led to increasing the membrane permeability of Saccharomyces cerevisiae in a very short time. Meanwhile, the rate of stained cell was 39.4% and the MDA content increased 50.0% compared with control. The content of ROS and MDA were increased by 4.8%,12.7%,169.8%, and 20.8%, 65.5%,112.5% respectively after 24 hours of treatment with PFOA of 1、10 and 100 mg·L-1, while RFI had the decrease of 9.9%,16.5% and 33.1%. When treated for 36 hours, the ROS content were increased by 22.1%,35.6%,215.3% and MDA increased 40.9%,181.8%,286.4% in the PFOA concentrations of 1、10 and 100 mg·L-1 respectively. On the contrary, RFI decreased by 16.5%,16.8%, and 35.4% respectively. Therefore, it can be obtained that the content of ROS and MDA was positively, while RFI was negatively, correlated with the time and concentration of PFOA. Moreover, the activities of Na+K+-ATPase, Ca2+Mg2+-ATPase and Total-ATPase in Saccharomyces cerevisiae increased firstly, and then decreased under the stress of PFOA.(3) By GC/MS, 11 compositions of fatty acids of Saccharomyces cerevisiae were detected. When treated with PFOA, the 18:2ω6,9 of Saccharomyces cerevisiae had the highest content. The content of 18:2ω6,9 was negatively correlated with the concentration of PFOA, and the same is that of the rate of UFAs. By contrast, the rate of 16:1ω7t/16:1ω7c was positively correlated with the concentration of PFOA.