Project description:Hypersaline regions are terrestrial analogs of the Earth's primitive ecosystem and extraterrestrial environment. The salt range in Pakistan is considered among a few of the ancient salt deposits in the subcontinent. Karak salt mine is situated at the Northwest end in Pakistan. Despite the fact that halophiles initiated the formation of terrestrial ecosystems, their products and identities remain hidden. Some preliminary studies limited to culture-dependent isolations have been reported. Characterizing the microbiome that spans over centuries of ecosystem development is crucial, given their role in shaping landscape succession and biogeochemical cycles. Here, we used metagenomics techniques to explore the microbial diversity of the Karak salt mine. We used 16S rRNA Illumina amplicon sequencing to characterize the halophilic communities entrapped in Karak mine. The results were interpreted using Illumina Basespace, QIIME, and Cytoscape. Cultures were isolated at 16-25% salinity. Metagenomics data was consistent with our preliminary culturing data, indicating remarkable species to strain-level diversity of unique halophiles. A total of 107,099 (brine) and 122,679 (salt) reads were obtained. 16S rRNA based sequencing revealed a microbiome with bacteria (66% brine and 72% salt) dominated by Bacteroidetes and Proteobacteria with a strikingly high abundance of Archaea (18% brine and 13% salt). Alpha diversity has higher values in salt than in the brine. The study of the halophiles in the Karak salt mine provides clues for species contributing to the maintenance of biogeochemical cycles of the ecosystem. This is the first report of a metagenomic study of any hypersaline region of Pakistan.
Project description:Transcriptional profiling of an El Tor biotype crp mutant The virulent V. cholerae El Tor Ogawa strain C7258 (Peru isolate 1991) and an isogenic deletion mutant (WL7258) lacking DNA sequences encoding the cAMP receptor protein were grown in LB medium to optical density at 600 nm of 1.5. The cultures were chilled in ice, cells quickly collected by centrifugation and total RNA imediately extracted. RNAwas extracted and purified using the Trizol plus RNA purification system (Invitrogen) followed RNEasy miniElute cleanup (Qiagen). RNA samples were conserved at - 80 C and used within a week. Keywords: Genetic modification