Toxicity Study Of The Individual And Combined Exposure Of DBP And MBP On Gracilaria Lemaneiformis

As a primary producer of marine ecosystems,the large seaweed Gracilaria lemaneiformis has multiple functions such as ecological restoration,anti-tumor activity and agar extraction,which contributes a great force to the marine ecosystem.DBP is a typical environmental hormone.Due to its chemical nature,it is easy to diffuse and migrate in the environment.It is often detected in marine water bodies and marine organisms.In recent years,DBP's primary metabolite MBP has also received extensive attention.At present,there are few studies on the toxicity of DBP and MBP for the association of Gracilaria lemaneiformis.In this paper,the large seaweed Gracilaria lemaneiformis was used as the experimental research object,and the toxic effects of DBP and MBP on growth,photosynthesis,antioxidant system,antioxidant activity and anti-tumor activity were studied under single and combined action.The research results are as follows:DBP and MBP were able to inhibit the growth of Gracilaria lemaneiformis in the concentration range of 5-100 mg/L.After 15 days of single exposure at 100 mg/L,the relative growth rate of DBP was lower than that of MBP exposed group.4.78 times,and both showed a negative growth rate,the toxicity was DBP>MBP.Under combined exposure,the lowconcentration combined exposure group(DBP 5 mg/L+MBP 5 mg/L)showed an additive effect,and the remaining concentrations in combination with the exposed group showed an antagonistic effect.DBP,MBP single and combined exposure had a certain degree of damage to the photosynthetic system of Gracilaria lemaneiformis.On the third day of single exposure,the chlorophyll a content of DBP and MBP single exposure group at 5 mg/L was higher than that of the control group.6.9% and 11.70%,the phycoerythrin content increased by 30.15% and 7.41%,respectively.On the 15 th day of single exposure,the chlorophyll a content of DBP and MBP exposure groups decreased by 17.89%-56.38%,respectively.20.45%-42.02%,the phycoerythrin content decreased by 6.6%-54.10% and 4.49%-35.94%,respectively.Under combined exposure conditions,chlorophyll a showed an additive effect in the low-concentration combined exposure group(DBP 5 mg/L+MBP 5 mg/L),and the remaining concentrations in combination with the exposed group showed an antagonistic effect;phycoerythrin at all combined concentrations The antagonistic effect was shown in both exposed groups.The content of soluble protein could reflect the effect of DBP,MBP single and combined exposure on the metabolic ability of Gracilaria lemaneiformis.On the third day of single exposure,the soluble protein content of Gracilaria lemaneiformis chinensis in the DBP and MBP exposed groups was 1.03% higher than that of the control group.On the 15 th day,the soluble protein content of DBP and MBP exposure groups decreased to 1.05-1.95 mg/g and 1.66-2.11 mg/g,respectively.Under combined exposure conditions,the effect on the soluble protein content of Gracilaria lemaneiformis officinalis showed an additive effect.The contents of UV absorbers and nitrate reductase(NR)decreased with the increase of DBP and MBP exposure concentrations.Under combined exposure,the effects on UV-absorbing substances and nitrate reductase activity of Gracilaria lemaneiformis officinalis showed antagonistic effects..DBP,MBP single and combined exposure can cause a certain degree of oxidative damage to Gracilaria lemaneiformis.After 15 days of exposure,the superoxide anion radical and MDA content in DBP single exposure group increased by 35.71%-246.19% compared with the control group.31.07%-127.15%;the superoxide anion radical and MDA content in MBP single exposure group increased by 24.29%-126.67% and 9.45%-108.75%,respectively.Under the combined exposure,the effect on the content of superoxide anion radicals showed an additive effect,and the effect on MDA content showed an antagonistic effect in the high concentration combined exposure group,and the other concentrations combined with the exposed group showed an additive effect.When the exposure of Gracilaria lemaneiformis had very severely damaged,the superoxide anion radical and MDA content will decrease.The damage of antioxidant enzymes(SOD,CAT)in the body was induced by the damage of the algae body.The maximum activities of SOD and CAT were 2.09 and 2.30 times,1.64 and 1.57 times of the control group under DBP and MBP single exposure,respectively.Under combined exposure conditions,the effect on SOD activity was shown to be additive in the low-concentration combined exposure group,and the other combined concentrations showed an antagonistic effect;the effect on CAT activity was in the DBP 100 mg/L+MBP 5 mg/L combination.The exposed group showed an additive effect,and the other combined concentration groups showed an antagonistic effect.When Gracilaria lemaneiformis were exposed to DBP and MBP,the scavenging free radical ability and anti-tumor activity of MEGT were inhibited.