Screening,identification And Mechanism Of A Trivalent Arsenic Oxidizing Bacteria

Arsenic and its compounds are common environmental pollutants.The abundance of arsenic in the crust is about 1.8ppm.The content of arsenic in rock and soil is less than1 ppm to several hundred ppm,and the widespread existence of arsenic in nature leads to the inevitability of arsenic pollution.Arsenic is a kind of metal,which is a kind of amphoteric element,and has both metallic and non-metallic properties.The toxicity and some properties of arsenic are similar to those of heavy metals,and are often combined with heavy metal ions in natural environment to form compound pollution.Arsenic is a carcinogen that has been determined by human beings.Excessive intake of arsenic can lead to skin cancer,lung cancer and various cardiovascular diseases,neurological diseases.Microorganisms play an important role in the natural cycle of arsenic.Trivalent arsenic oxidizing bacteria refer to a class of bacteria that can oxidize As(III)to As(V)through the effect of bacterial internal enzymes.The oxidation of arsenic in microbes has two important points: one is that the toxicity of As(III)is stronger than As(V).Therefore,the toxicity of arsenic in the environment can be reduced by the oxidation reaction.At the same time,the oxidation reaction process of arsenic trivalent oxidizing bacteria through arsenic oxidation process is also found.The energy produced in the medium is metabolized and grown.Most trivalent arsenic oxidizing bacteria are isolated from arsenic enriched or heavy metal enriched environments.Microorganism has large specific surface area,is easy to reproduce,has a wide range of distribution,and has a wide range of distribution.In addition,microorganisms can be oxidized as electron transporter or receptor,and also secrete related biological enzymes to oxidize or methylation As(III).Therefore,microbial technology also occupies a very important position in the treatment of arsenic pollution,and is the most developing potential.The method of force.In this study,64 strains of arsenic tolerant strains were isolated from the soil samples and water samples obtained from a smelter in Huangshi.The oxidation capacity of trivalent arsenic in single colony was identified.A strain was found to oxidize As(III)to As(V)in the medium environment,and its oxidation rate was close to 100% and was named as No.9.It was identified as Pseudomonas sp.by strain.The ability of Pseudomonas to oxidizearsenic has been reported in literature,but few reports have been done about its oxidation mechanism and regulation.By monitoring the common environment of the bacteria,the environment of trivalent arsenic and other common heavy metal environment,the growth characteristics of the bacteria and their growth in the complex environment were obtained.RNA-Seq,a transcriptional sequencing technique,is a method used to analyze the comprehensive characteristics of the transcriptional text at the gene level and exon level,and is also a unique analytical tool for identifying new shear mutations.Transcriptome is the collection of all RNA,including m RNA and non coding RNA,in specific physiological state of a specific species,tissue or cell.The difference of gene level and exon level in the whole transcriptional process was compared and analyzed by RNA sequencing(RNA-Seq)in the normal environment and high concentration of arsenic trivalent arsenic(RNA).The difference in the expression of key genes in various metabolic pathways was compared to analyze the role of the strain in the arsenic oxidation reaction.