Separation and identification of archaea from radioactive pollution

Abstract:

[Objective] This study was to investigate the diversity of archaea from radioactive pollution environment. [Methods] Glycerin-arginine medium (GJ), Glycerin-aspartic acid medium (C1), Trehalose-creatine medium (B7), Mannitol-alanine medium (Z5), Casein-mannitol medium (CMKA), Chitosan-asparagine medium (F6), Mannitol-acid hydrolysis of casein medium (GW1), CM, HP, and KC media with different salinities were used for isolating archaea from radioactive pollution areas. Different isolates selected on the basis of morphological characteristics and Hae III digestion patterns of 16S rRNA genes. The results of 16S rRNA gene sequences were compared with sequences obtained from GenBank databases. Phylogenetic tree was constructed by the Neighbor-Joining method. [Results] Total 256 archaeal strains were obtained by different selective media, and belonged to 71 different types. They were members of Haloterrigena, Natrialba, Halococcus, Halorubrum, Halovivax, Natrinema, Natronococcus, Halobiforma, Halostagnicola, Halopiger, Natronorubrum and Haloferax genera. The similarities between detected sequences (34% of total strains) and published sequences were less than 98%. They formed distinct clades in phylogenetic tree and might represent new taxa. Haloterrigena was the dominant group. Nineteen strains were obtained by different Chitosan-asparagine medium (better isolating medium) ten-fold dilution culture. Compared with strains by Chitosan-asparagine medium, they were different groups. [Conclusion] The radioactive pollution area harbors abundant archaea, including large number of unknown bacterial groups, has a great research value.