June 2, 2008
By Syed Akbar
Hyderabad: The unknown depths of the Indian Ocean is full of microbial activity and
is a rich repository of hidden wealth of animal diversity.
Scientists at the Hyderabad-based Centre for Cellular and Molecular Biology in collaboration with their counterparts at the National Institute of Oceanography, Goa have successfully isolated culturable bacteria from the deep-sea sediments of the Indian Ocean.
The bacterial collection came from the Chagos Trench in the Indian Ocean below the water depth of 5904 metres. The CCMB-NIO team isolated bacteria from 50 to 70 cm section of a 4.6 metres long sediment core deep in the seas.
What has baffled the scientific team is that the sediments were about 50,000 years old. From the sediments came out two entirely new species of bacteria. The scientists have named it Brevibacterium oceani after they sequenced the bacteria using a technique known as "16S rRNA sequencing".
"The almost-complete 16S rRNA gene sequences of these two strains showed 99.9 per cent similarity among themselves. Following a scientific analysis, the two strains showed 97.9 to 98.4 per cent similarity to other Brevibacterium species. DNA-DNA dot-blot hybridisation of these two strains with other known Brevibacterium species showed relatedness of only 35-41 per cent. A DNA-DNA relatedness of 70 per cent is used as the cut-off point for species delineation. Based on these results and differences in other phenotypic characteristics, these two strains belong to a novel species and the new species name Brevibacterium oceani was proposed," an NIO report
said.
According to the NIO report, from the same sediments, two more new strains belonging to a new species Microbacterium indicum were found. Biochemical characteristics, fatty acid profile, polar lipid contents and levels of DNA-DNA hybridisation techniques were used to report this new species. "These results indicate that deep-sea sediments hold a hidden wealth of microbial diversity which remains to be
explored," the joint study by CCMB-NIO teams felt.
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