Research On The Hormesis Of Three Kinds Of Quinolone Antibiotics In Dunaliella Salina

The Hormesis effect is a special phenomenon that is different from the traditional dose-effect relationship of toxicology.It refers to a certain benign stimulatory effect when the body is exposed to low doses of pollutants,and it exhibits an inhibitory response under high dose conditions.The existence of the Hormesis effect means that when the organism is stressed by low-concentration contaminants,its biological response may be completely different from that of traditional risk assessment studies.Quinolone antibiotics are one of the most widely used antibiotics due to their broad antibacterial spectrum,strong antibacterial activity and low toxic and side effects,but because most of them are not absorbed by organisms,they cause large amounts of residues in the environment and can migrate into seawater.A sustained low-dose exposure profile was exhibited.As a primary producer of seawater,D.salina not only provides the oxygen needed for aquatic organisms,but also is the basis of the marine food chain,and its pollution can be transmitted to other trophic levels through the food chain.At present,the pollution of antibiotics in seawater is becoming more and more serious.The effect of quinolone antibiotics on D.salina,whether it produces Hormesis effect is the focus of this study.In this paper,Dunaliella salina was selected as the test substance to observe the effects of three quinolone antibiotics on the growth,physicochemical properties and antioxidative parameters of Dunaliella salina.The specific research content is as follows:(1)Establish growth curve of D.salina,and measure three kinds of concentration gradients of low concentration(10-3,10-2,10-1 mg·L-1)and high concentration(1,10,100 mg·L-1).The change of the absorbance after 24 h,48 h,72,and 96 h of the effect of antibiotics on D.salina was used to calculate the density of algal cells through the growth curve of D.salina.The results showed that the low concentration group had a promoting effect on the growth of D.salina,and the proliferation effect was significant at 96 h(P<0.05).The concentrations of 10-3 mg·L-1 were the antibiotics of ciprofloxacin,norfloxacin,and pipemidic acid.At 96 h,the accumulative rate was 111.9%,108.5%,and 107.5%.The high-strength antibiotic group had an inhibitory effect on the growth of D.salina,and the three high-concentration antibiotics treated Dunaliella for 96 h with a significant inhibitory effect(P<0.05)and a concentration of 100 mg.L-1 three kinds of antibiotics ciprofloxacin,norfloxacin,pipemidic acid effect Dunaliella 96h,the greatest inhibition rate,respectively,90.5%,91.3%,94.6%.(2)Three kinds of antibiotics were used to treat Dunaliella salina at a low concentration(10-3,10-2,10-1 mg·L-1)and high concentrations(1,10,100mg·L-1).Observed the changes of chlorophyll,?-carotene and soluble protein content.The results showed that the three antibiotics were treated with low concentration for 96 hours.The contents of chlorophyll,?-carotene and soluble protein in Dunaliella salina were increased,and the antibiotic was 10-3 mg-L-1.The content of chlorophyll,?-carotene and soluble protein in Dunaliella salina was decreased at the 96 h after treatment with the highest concentration(P<0.05).<0.01).(3)Three kinds of antibiotics acted on Dunaliella salina under low concentration(10-3,10-2,10-1mg·L-1)and high concentration(1,10,100mg·L-1).Observed the changes of superoxide dismutase,glutathione,malondialdehyde oxidation index.The results showed that the activity of SOD increased and GSH content decreased after treatment with 10-3mg·L-1 antibiotics in low concentration group for 96h(P<0.05),but no significant effect on MDA;The activity of SOD and the content of MDA increased significantly after treatment with Dunaliella for 96 h,and the content of GSH decreased significantly(P<0.05),and the three antibiotics with 100 mg-L-1 had the most significant effect(P<0.01).The 10-2 and 10-lmg/L antibiotics also affected the antioxidant index of D.salina,but the effect was not significant.Through the above studies,it was found that three quinolone antibiotics induce Hormesis effect in Dunaliella salina,and low concentrations of three antibiotics will promote the growth of Dunaliella salina and increase the content of chlorophyll,?-carotene and soluble protein in algal cells.The algal cell antioxidant system activates.High concentrations of three antibiotics inhibit the growth of Dunaliella salina,while blocking the synthesis and physiological metabolic activity of chlorophyll in algal cells,and cause oxidative stress in algal cells.