| Because of its extreme drought,dryness,high ultraviolet radiation(a large number of UV-A and UV-B ultraviolet rays),large temperature difference and a little precipitation,most of the animals and plants can not survive under these conditions of desert.However,in the desert ecosystem,as a small number of biological groups,microorganisms can survive tenaciously in the this ecosystem.In the desert ecosystem,as the dominant organism of the ecosystem,the microorganism is able to survive the high radiation,high oxidation and extreme drought in the desert,which shows that the desert microorganisms have formed the resistance mechanism in such an environment to protect its own survival and generation.Through the study on the mechanism of anti radiation and anti-oxidation of culturable microorganisms in desert,it can provide scientific basis and theoretical support for the resources of anti radiation and oxidative damage.In this paper,by culturable microorganisms in the Taklimakan Desert,the diversity of culturable microorganisms in the Taklimakan Desert was studied,and then by ways of UV-C and?ray irradiation,the culturable bacteria in the Taklimakan Desert were screened for radiation resistance.The anti-oxidation research and metabonomics analysis of strain T1057 were figured out on the selected strong anti radiation strains and the resistence-radiation strains in Kumutag desert provided by the Key Laboratory of environmental microorganism resources and engineering of Gansu Province,Chinese Academy of Sciences.The results show that:1.A total of 2216 isolates were isolated from Taklimakan Desert,attributed to 4different phyla,respectively Actinobacteria,Firmicutes,Bacteroidetes and Proteobacteria,43 different genera and 352 different species.At the phylum level,Actinobacteria is the most dominant phylum from relative abundance among the culturable microorganisms in Taklimakan Desert.As well,Actinobacteria and Firmicutes are the dominant gates in CFU.2.In the Taklimakan desert from north to south,the distribution diversity of different species of microorganisms is different.At the gate level,TOC,TC,TN,WC,EC content and pH value were significantly correlated with the bacterial abundance of Actinobacteria,Firmicutes and Proteobacteria.Different environmental factors have significantly correlation effects on the distribution diversity and species diversity of bacteria in different phylum,and the ecological respond of this effect is different.3.The bacteria isolated from Taklimakan were irradiated by UV-C and?rays,and the bacteria with high radiation resistance were screened out.In addition to Bacteroides,there were 10 bacteria with stronger radiation-resistance than that of Deinococcus radiodurans,which were irradiated by HR(6000 J/m~2 UV-C).The results showed that:TKL1057(Kocuria indica),TKL798(Streptomyces griseoviridis),TKL860(Citricacus zhacaiensis),TKL1152(Planococcus citreus),TKL19(Gracilibacillus thalandensis),TKL588(Bacillus subtilis subsp.Inaquosorum),TKL606(Pseudomonas xanthomarina),TKL865(Paracoccus hibisci),TKL855(Pseudochrobactrum saccharolyticum)and TKL 35(Altererythrobacter soli),the radiation resistance of 10 strains was stronger than Deinococccus rRadiodurans.4.TKL1057(Kocuria indica)?TKL1152(Planococcus citreus),the ability of resistance-radiation of these two strains is stronger than Deinococccus Radiodurans,meanwhile,other strains',except above two,survival rates tends to the value of 0.Thay means both TKL1057 and TKL1152 are the most resistant-radiation strains.5.Through antioxidant screening,we found that the antioxidant survival rate of different anti-radiation strains was TKL 1057>K81>TKL 1152>TKL 798>AQ(positive control)>k146>K202>TKL 865>k59>BL(negative control).At the same time,we also found that the concentration of resistant stress of different anti radiation strains was different.The antioxidant strains had good scavenging ability to DPPH,OH·and O~2-·radicals under oxidative stress,and the MDA content was also higher under oxidative stress.6.The metabolism of TKL1057(Kocuria indica)was determined after radiation and oxidation stress.It was found that after radiation and oxidation stress.The metabolites and metabolic pathways of TKL1057 have been done change significantly.After radiation,61 kinds of metabolites were expressed,40 kinds of metabolites were expressed after oxidation,40 kinds of metabolites expressed after radiation and oxidation were the same.At the same time,the analysis of foreign bodies in different treatments showed that the metabolism of cells after radiation was mainly based on the basic metabolism of sugar and secondary synthesis After oxidation treatment,organic acid is the main metabolite to synthesize secondary metabolites. |
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