Study On Atrazine Toxicological Effect Of Four Kinds Of Typical Bacteria

Atrazine is long residual herbicides,by the United Nations environment programme(UNEP)listed as one of the 28 kinds of persistent toxic chemical pollutants,the environmental problem has gained wide attention.Environmental behavior of atrazine and bioremediation technology has become a hot research topic in the field of pesticide pollution control.The northeast black earth area in China,atrazine has become an important agricultural pollutants,causing greater damage to the black soil area environment.Due to earlier microbes can forecast the changing process of soil environmental pollution condition,this article with gram-negative bacterium Escherichia coli K12(E.coli K12)and gram-positive bacterium Bacillus subtilis B7(B.subtilis B7),as well as from the black soil of atrazine degradation bacteria Arthrobacter sp.DNS 10 and Acinetobacter Iwoffii.DNS32 do contrast,use of modern molecular biology methods,from the microbial growth,oxidative stress,membrane lipid peroxidation damage and atrazine on microorganism DNA damage and so on toxicology effect of atrazine on the microorganisms,hope for atrazine toxicity and to provide theoretical basis for the ecological security evaluation.The main results were as follows:1)After a concentration of 0.1,0.5,5,10 and 20 mg·L-1 atrazine stress for 24 h,gram-negative bacteria E.coli K12,gram positive bacteria B.subtilis B7,Arthrobacter sp.DNS 10 and Acinetobacter sp.DNS32 growth rate was not significantly suppressed,that atrazine did not affect the growth of bacteria number.2)After a concentration of 0.1,0.5,5,10 and 20 mg·L-1 atrazine stress for 12h,18h,24h and 36h,E.coli K12 and B.subtilis B7,happened to the super oxygen free radicals in cells increased with the concentration of atrazine stress increased after the first reduce trends,change is not big,however,compared with the control group were lower than 30%.But the super oxygen free radical content changes of atrazine stress concentration is more sensitive.Strains of Arthrobacter sp.DNS 10 intracellular oxygen free radicals in stress after 12 h and significant changes have taken place in 18 h,up to 33.12%in the control group.Strains of Acinetobacter sp.DNS32 super oxygen free radical content change is not obvious in the cell.3)TBA method is used to detect the typical bacteria malondialdehyde content changes in the cell.Found that atrazine pollution stress can improve the strain E.coli K12 and B.subtilis B7 intracellular malondialdehyde content,membrane lipid peroxidation damage,and then to the toxicity of organisms to produce more Increased when the concentration of atrazine pollution threats to 10 mg·L-1,the strain of e.coli K12 intracellular MDA content is 2.61 nmol mgprot-1,about three times of control;Strain of b.subtilis B19 intracellular MDA content is 3.76 nmol mgprot-1.almost four times as the control group.And there is an obvious dose-effect relationship.And atrazine degradation bacteria Arthrobacter sp.DNS 10 and Acinetobacter sp.DNS32 intracellular malondialdehyde rise which is small,even strain DNS 10 within a certain range time-concentration can lower malondialdehyde content in the cell.4)By using random amplified polymorphic DNA(RAPD)detection of atrazine pollution in the study of bacterial DNA damage,and calculate the four kinds of bacterial genome stability,proved that atrazine pollution stress caused the E.coli K12 and B.subtilis B7 toxic and genome DNA damage.Reduces the stability of the genome DNA template.And dose-effect relationship.When atrazine concentration of 20 mg· L-1,have been reduced to about 60%.But under the stress,atrazine degradation bacteria Arthrobacter sp.DNS 10 and Acinetobacter sp.,DNS32 in atrazine stress concentration of 20 mg·L-1 case will still be able to reach more than 90%of the genetic stability.