Micro-Calorimetric Method For Studying The Toxic Effect Of Organic Arsenic On Bacillus Thuringiensis Of Wild And Engineering Strains

Arsenic(As) is a common environmental pollutant.This metalloid is well known for its carcinogenic and teratogenic effects.Organoarsenic compounds are using in agricultural practice since long time.Due to use of organic arsenic pesticide and herbicide our soil environment are polluted.So from that point of view we are are select the oranoarsenic compound to evaluate its toxicity on Basicillus thuringiensis of wild and engineering strains for this research work.Arsenic(As) and its compounds are ubiquitous in nature and exhibit both metallic and nonmetallic properties.The trivalent and pentavalent forms are the most common oxidation states.From both the biological and the toxicological points of view,arsenic compounds can be classified into three major groups:inorganic arsenic compounds;organic arsenic compounds;and arsine gas.The most common trivalent inorganic arsenic compounds are arsenic trioxide,sodium arsenite and arsenic trichloride.Pentavalent inorganic compounds include arsenic pentoxide,arsenic acid and arsenates,e.g.lead arsenate and calcium arsenate.Common organic arsenic compounds are arsanilic acid,methylarsonic acid,dimethylarsinic acid(cacodylic acid) and arsenobetaine.Arsenic trioxide is only slightly soluble in water;it forms arsenite in sodium hydroxide and arsenic trichloride with concentrated hydrochloric acid.Sodium arsenite and sodium arsenate are highly soluble in water.Interchanges of valence state may occur in aqueous solutions,depending on the pH and on the presence of other substances which can be reduced or oxidized.The new standard highlights a national concern on the health effects of arsenic. The extensive use of organoarsenical compounds such as in some pesticides in agriculture has become an emerging source of arsenic contamination in the environment.The environmental impact is significant when considering that huge quantities of arsenic are spread onto relative small areas in the direct vicinity of agricultural lands.The aim of this study is to evaluate the toxicity of organo arsenic compounds and role of soil microbes under anaerobic and aerobic condition using most promising micro-calorimetric methods combined with pure microbiological methods,the study compares Genetically Modified microbes(GMO) with natural soil microbes.This dissertation work is divided into three sections:A.Discuss the different micro-calorimetric methods in the environmental point of view.Find out the efficient micro-calorimetric method for monitor the microbial activity with presence of different heavy metals.B.Monitor the specific microbial activity by micro-calorimetric method. Analyze the exothermic effect from micro-calorimeter and compare with pure biological methods.Two types of Organoarsenic(V) compounds used are monometylearsonic acid(MMA) and dimethyl arsenic acid(DMA).We selected wild strain of Bacillus thuringiensis.We find out that the wild strain are highly resistant against organoarsenic(V) compounds.Form this work we have been successfully proof that organoarsenic are toxic to the microbes. Our microcalorimetric methods are best suited to complete this work.C.Choose some GMO microbes as a continuation our previous work.We selected two kinds of strain Bacillus thuringiensis which are mentioned as B. thuringiensis A and C.,monitored their activity with microcalorimetric methods.And confirmed our objectives with some new analysis methods.To evaluate the toxicity of microbes against organoarsenic(V) compounds,we also measured the decrease of dissolve oxygen(DO mg L^-1) in the absence of organoarsenic(V) compounds with other biological methods measuring the microbial growth rate and activity with different doses of organoarsenic(V) compounds.And finally we have been successfully get our targeted result what is given us the doses response and toxicity of metal ion on soil microbes.A detailed description of the information contained in each chapter is presented in the dissertation overview section.