Study On The Toxicity Of Earthworm Under Tetracycline Stress

Antibiotics are widely used in daily life and production.Some antibiotics cause potential harm to the safety of the ecological environment due to their high residual and difficult to degrade,and they have a great impact on soil ecosystems.As an indicator of the health of the soil ecosystem,earthworms can be used to judge the potential harm and degree of pollutants in the soil to a certain extent.In this experiment,Eisenia fetida was used as the research object,and tetracycline was used as the exogenous stress substance.(1)Study on the acute toxicity of earthworms by using the filter paper test method.(2)Explore the oxidative stress processes in earthworms under different stress times by using artificial soil test methods.(3)Use the factor analysis model to screen out the main oxidative stress indicators that can indicate the degree of stress in earthworms under different stress concentrations.(4)The artificial soil test was used to explore the oxidative stress process in earthworms under different stress time.(5)Establish a canonical correlation analysis model to study the changes in the use of different carbon sources by microorganisms in earthworm.(6)To explore the relationship between functional diversity of microbial communities and oxidative stress effects in earthworms under different stress concentrations.This article aims to clarify the toxic effects of tetracycline stress on earthworms,and to explore the mechanism of poisoning in earthworms under tetracycline stress,which is of great significance for evaluating the ecological risks of tetracycline antibiotics.The results are as follows:(1)There are differences in the oxidative stress process in different parts of earthworms.Stress for 1-3 days: SOD plays a major role in the head tissues of earthworms.The detoxifying enzyme GST exerts a detoxifying effect on the head of the earthworm.Stress 4-7 d: SOD plays an antioxidant role in the head tissue of earthworms.The detoxifying enzyme ACh E plays a detoxifying effect on the head of the earthworm.Stress for 8-10 days: GPX plays a major role in the heads of earthworms.The detoxifying enzyme ACh E still exerts a detoxifying effect on the earthworm head.Stress for 20-30 days: CAT and GPX play a major role in the head of the earthworm,while POD plays a major role in the tail of the earthworm.MDA appears in the tail tissue of earthworms.The detoxifying enzyme GST works mainly in the tail of earthworms,while ACh E w orks in the head of earthworms.(2)Factor analysis was used to quickly screen out the main oxidative stress indicators that could indicate the degree of stress in earthworms under different stress concentrations.The main oxidative stress indicators of earthworm head tissue under low concentration(0.3,3 mg / kg)stress are SOD,POD and GST.At moderate concentrations(30 mg / kg),the main oxidative stress indicators in the head tissue are CAT and GPX.At high concentrations(300,600 mg / kg),the main oxidative stress indicators of the head tissue are GPX,MDA.The main oxidative stress indicators in the tail tissue of earthworms under low concentration stress were CAT,GST and SOD.The main oxidative stress indicators of tail tissue under moderate concentr ation stress were POD and GST;the main oxidative stress indicators of tail tissue under high concentration stress were SOD,POD,CAT and ACh E.(3)The functional diversity of microbial communities in earthworms showed different trends with the extension of stress time: At the beginning of short-term stress,Shannon-wiener and Shannon index increased significantly with increasing stress time,while Simpson index and Mc Intosh index increased slightly.In the early stage of stress,the Shannon-wiener index changed little,and the Shannon,Mc Intosh index and Simpson index were significantly inhibited.In the middle period of stress,the Shannon and Mc Intosh index rebounded.In the later period of stress,the Simpson index began to increase.With the extension of st ress time,the functional diversity index of microbial community did not change significantly under long-term stress.(4)The utilization intensity of different carbon sources by microorganisms and the relationship between the oxidative stress effect and the functional diversity of the microbial community in earthworms under different stress concentrations: Under low-concentration tetracycline stress,the use of carbohydrate carbon sources by the microbial community in earthworms is higher.As the concentration increases,the utilization of amino acids and phenolic acids by microorganisms was promoted.At higher concentrations of tetracycline stress,microorganisms using carboxylic acid carbon sources dominate.The CAT,POD,SOD,GPX were related to the microbes that use carbohydrate carbon sources;the GST and ACh E were related to the microbes that use polymer carbon sources;the MDA was related to the microbes that use carbon sources: amino acid,carboxylic acid and phenolic acid.