Phylogenetic and Physiological Diversity of Bacteria Isolated from Puruogangri Ice Core |
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Authors: | X F Zhang T D Yao L D Tian S J Xu L Z An |
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Institution: | (1) Cold and Arid Regions Environment and Engineering Research Institute, Chinese Academy of Science, Lanzhou, Gansu, 730000, People’s Republic of China;(2) School of Life Science, Lanzhou University, Lanzhou, 730000, China;(3) Institute of Tibet Plateau Research, Chinese Academy of Sciences, Beijing, 100029, China;(4) Gansu Provincial Hospital, Lanzhou, 730000, China |
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Abstract: | The microbial abundance, the percentage of viable bacteria, and the diversity of bacterial isolates from different regions
of a 83.45-m ice core from the Puruogangri glacier on the Tibetan Plateau (China) have been investigated. Small subunit 16S
rRNA sequences and phylogenetic relationships have been studied for 108 bacterial isolates recovered under aerobic growth
conditions from different regions of the ice core. The genomic fingerprints based on ERIC (enterobacterial repetitive intergenic
consensus)-polymerase chain reaction and physiological heterogeneity of the closely evolutionary related bacterial strains
isolated from different ice core depths were analyzed as well. The results showed that the total microbial cell, percentages
of live cells, and the bacterial CFU ranged from 104 to 105 cell ml−1 (Mean, 9.47 × 104; SD, 5.7 × 104, n = 20), 25–81%, and 0–760 cfu ml−1, respectively. The majority of the isolates had 16S rRNA sequences similar to previously determined sequences, ranging from
92 to 99% identical to database sequences. Based on their 16S rRNA sequences, 42.6% of the isolates were high-G + C-content
(HGC) gram-positive bacteria, 35.2% were low-G + C (LGC) gram-positive bacteria, 16.6% were Proteobacteria, and 5.6% were CFB group. There were clear differences in the depth distribution of the bacterial isolates. The isolates
tested exhibited unique phenotypic properties and high genetic heterogeneity, which showed no clear correlation with depths
of bacterial isolation. This layered distribution and high heterogeneity of bacterial isolates presumably reflect the diverse
bacterial sources and the differences in bacteria inhabiting the glacier’s surface under different past climate conditions. |
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