Preliminary Study On Resources Of Actinomcetes In Salty Environments Of Dead Sea

In this study, actinomycete resources and effects of different treatments on the isolationof actinomycetes from the tested soil samples, which were collected from the Dead Sea area,were analyzed. Halophilic and salt tolerance of the isolates, combined and screened on thebasis of phylogenetic analysis, was tested. The isolates were identified by polyphasictaxonomy. The results as follows:1. Four media, Gause’s synthetic agar, modified starch casein agar, modified ISP5andCMKA, and four salt concentrations,15%,20%,25%and30%, of each medium were usedfor the isolation of actinomycetes. A total of70isolates were got from the tested soil samples,which were pretreated by microwave irradiation. Actinomycete counts and species numberswere varied with different samples and different media. Actinomycete species number wasNO1>NO3>NO4>NO2. The isolation result was best on CMKA medium, compared to theother media. Morphology of isolates was special on modified ISP5medium.2. Nine different methods, combined physical (microwave), chemical (spore activators)and enrichment, were adopted for the pretreatment of samples. Three media, ISP5, HV andCMKA, and three salt concentrations,15%,22.5%and30%, of each medium were used forthe isolation of actinomycetes. Then we draw a conclusion: choose microwave irradiation plusspore activator as the pretreatment method and CMKA medium with22.5%saltconcentration as the isolation medium is the best way for the isolation of actinomycetes.3. Phylogenetic analysis of78strains were done on the basis of16s rDNA. The resultsindicated:40strains were belonged to Nocardiopsis,4strains were belonged toSaccharopolyspora, three for Saccharomonospora, three for Halomonas, two for Halobacillus,one for Streptomonospora, one for Amycolatopsis and one for Pontibacillus, Twenty-three forunknown bacteria genus. Twenty-three different strains were left after screen and merge.4. There were distinct halophilic and tolerance differences between MgCl2, NaCl andmixed salt for23strains of actinomycetes abtained from Chapter4. For the mixed salt,21strains could grow on the medium with25%salt concentration and11strains were extremelyhalophilic actinomycetes. For MgCl2,18strains could grow on the medium with25%saltconcentration and14strains were extremely halophilic actinomycetes. For NaCl,17strains could grow on the medium with25%salt concentration and5strains were extremelyhalophilic actinomycetes. Besides, we got one strain, which was halophilic for MgCl2but notfor mixed salt and NaCl, one strain, which was halophilic for NaCl but not for mixed salt andMgCl2and four strains of media NaCl halophilic actinomycetes.5. Polyphasic taxonomy of21strains were analyzed. The results showed that two strainswere the same; nine strains were identified to species level; six strains were potentially novelspecies and three strains were potentially novel genus，two strains did not undeterminedtaxonomic status.