16S rRNA sequences and difference in bacteria isolated Muztag Ata Glacier at increasing depths

• Main Authors: Shurong Xiang, Ong Yao, Lizhe An, Bingliang Xu, Junxia Wang
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2005
• Subjects: ice core
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.688.7165; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1183274/pdf/0169-05.pdf

Small subunit 16S rRNA sequences, growth temperatures, and phylogenetic relationships have been estab-lished for 129 bacterial isolates recovered under aerobic growth conditions from different regions of a 22-m ice core from the Muztag Ata Mountain glacier on the Pamirs Plateau (China). Only 11 % were psychrophiles (grew at 2°C or 2°C up to 20°C), although the majority (82%) were psychrotolerant (grew at 2°C or 2°C up to 37°C). The majority of the isolates had 16S rRNA sequences similar to previously determined sequences, ranging from 85 % to 100 % identical to database sequences. Based on their 16S rRNA sequences, 42.6 % of the isolates were high-GC (HGC) gram-positive bacteria, 23.3 % were -Proteobacteria, 14.7 % were -Proteobac-teria, 14.7 % were Flavobacteria, and 4.7 % were low-GC (LGC) gram-positive bacteria. There were clear differences in the depth distribution, with Proteobacteria, HGC/Cytophaga-Flavobacterium-Bacteroides (CFB), Proteobacteria, LGC/CFB/HGC, Cryobacterium psychrophilum, HGC/CFB, Proteobacteria/HGC/CFB, and HGC/ CFB being the predominant isolates from ice that originated from 2.7 to 3.8, 6.2, 7.5, 8.3, 9.0, 9.7, 12.5, and 15.3 m below the surface, respectively. This layered distribution of bacterial isolates presumably reflects both differences in bacteria inhabiting the glacier’s surface, differences in bacteria deposited serendipitously on the glacier’s surface by wind and snowfall, and nutrient availability within the ice. Previous studies have recovered bacteria from ice cores re-