RESUMO
Abstract In this study for the first-time microbial communities in the caves located in the mountain range of Hindu Kush were evaluated. The samples were analyzed using culture-independent (16S rRNA gene amplicon sequencing) and culture-dependent methods. The amplicon sequencing results revealed a broad taxonomic diversity, including 21 phyla and 20 candidate phyla. Proteobacteria were dominant in both caves, followed by Bacteroidetes, Actinobacteria, Firmicutes, Verrucomicrobia, Planctomycetes, and the archaeal phylum Euryarchaeota. Representative operational taxonomic units from Koat Maqbari Ghaar and Smasse-Rawo Ghaar were grouped into 235 and 445 different genera, respectively. Comparative analysis of the cultured bacterial isolates revealed distinct bacterial taxonomic profiles in the studied caves dominated by Proteobacteria in Koat Maqbari Ghaar and Firmicutes in Smasse-Rawo Ghaar. Majority of those isolates were associated with the genera Pseudomonas and Bacillus. Thirty strains among the identified isolates from both caves showed antimicrobial activity. Overall, the present study gave insight into the great bacterial taxonomic diversity and antimicrobial potential of the isolates from the previously uncharacterized caves located in the world's highest mountains range in the Indian sub-continent.
Assuntos
Bactérias/isolamento & purificação , Bactérias/classificação , Microbiologia Ambiental , Biota , Antibiose , Paquistão , Filogenia , Bactérias/crescimento & desenvolvimento , Bactérias/genética , DNA Bacteriano/genética , DNA Bacteriano/química , DNA Ribossômico/genética , DNA Ribossômico/química , RNA Ribossômico 16S/genética , Análise por Conglomerados , Análise de Sequência de DNA , Euryarchaeota/isolamento & purificação , Euryarchaeota/classificação , Euryarchaeota/crescimento & desenvolvimento , Euryarchaeota/genética , DNA Arqueal/genética , DNA Arqueal/química , MetagenômicaRESUMO
An extreme halophilic bacterium was isolated from solar saltern samples and identified based on biochemical tests and 16S r RNA sequencing as Chromohalobacter sp. strain TVSP101. The halophilic protease was purified using ultrafiltration, ethanol precipitation, hydrophobic interaction column chromatography and gel permeation chromatography to 180 fold with 22% yield. The molecular mass of the protease determined by SDS PAGE was 66 kDa. The purified enzyme was salt dependent for its activity and stability with an optimum of 4.5 M NaCl. The optimum temperature for maximum protease activity was 75ºC. The protease was optimally active at pH 8 and retained more than 80% of its activity in the range of pH 7-10. Sucrose and glycine at 10% (w/v) were the most effective osmolytes, retained 100% activity in the absence of NaCl. The activity was completely inhibited by ZnCl2 (2 mM), 0.1% SDS and PMSF (1mM). The enzyme was not inhibited by 1mM of pepstatin, EDTA and PCMB. The protease was active and retained 100% it activity in 10% (v/v) DMSO, DMF, ethanol and acetone.