Biology subjects

Khot, V.

Publications and source records attributed to Khot, V..

3 recordsLinked to original sources

bioRxiv2026

Physiology, functional genomics and proteomics of Verruconatronum alginivorum gen. nov., sp. nov., a first haloalkaliphilic representative of the phylum Verrucomicrobiota from soda habitats

Despite the successful cultivation of many microbes from rich bacterial communities inhabiting alkaline soda lakes, members of the bacterial phylum Verrucomicrobiota have so far been detected only through metagenomics. Here, we used alginate as a selective substrate to enrich and isolate two strains of haloalkaliphilic Verrucomicrobiota. The isolates share identical 16S rRNA gene sequences representing a new genus lineage, and, together with other metagenome assembled genomes, a new family within Opitutales. Cells of strains AB-alg1T (from soda lakes) and AB-alg4 (from soda solonchak soils) are small and motile cocci forming submerged colonies in soft alginate agar. They are saccharolytic heterotrophs growing aerobically on polysaccharides (alginate, starch and inulin) and sugars (glucose, fructose, mannose, sucrose, melezitose, maltose and cellobiose). They also grow anaerobically by fermentation of alginate and D-mannose and by coupling incomplete denitrification to oxidation of alginate. Both isolates are obligately alkaliphilic and moderately salt-tolerant. The dominant membrane phospholipids include phosphatidylcholines and diphosphatidylglycerols (cardiolipins). The genome of AB-alg1T features polysaccharide lyases of the PL6, 7, 15, 17, 38, and 39 families for depolymerization of alginate. Based on distinct phenotype and phylogeny, we propose classification of strains AB-alg1T (JCM 35393T=UQM 41574T) and AB-alg4 as Verruconatronum alginivorum gen. nov., sp. nov. within a new family Verruconatronumaceae. ImportanceThe presented isolates are the first isolated representatives of an environmental family of Opitutales, part of the core microbiome of alkaline soda lakes. These bacteria feed on polysaccharides. We present the key enzymatic machinery for the polysaccharide breakdown. These enzymes are high-pH tolerant and have potential for industry applications, for example in washing powders and biomass waste recycling.

microbiology↗

bioRxiv2023

Viral diversity and dynamics, and CRISPR-Cas mediated immunity in a robust alkaliphilic Cyanobacterial consortium

In many industries, from food to biofuels, contamination of production systems with predators is a costly problem and requires the maintenance of sterile operating conditions. In this study, we look at the robustness of one such alkaliphilic consortium, comprised largely of a cyanobacterium Candidatus Phormidium alkaliphilum, to viral predation. This consortium has existed without a community crash over several years in laboratory and pilot scale environments. We look at CRISPR-Cas systems and viral dynamics in this consortium at four conditions using metagenomic analyses. Results show that while there are active viral members in this community, viral predation of the cyanobacteria is low and does not affect the community dynamics. The multiple CRISPR arrays within the Phormidium were found to be static following initial lab establishment of consortium. Multiple cryptic CRISPR-Cas systems were detected with uncertain viral protection capacity. Our results suggest that dynamics of potential viruses and CRISPR-Cas mediated immunity likely play an important role in the initial establishment of consortia and may continue to support the functional robustness of engineered microbial communities throughout biotechnology applications. ImportanceBiotechnology applications utilizing the function of microbial communities have become increasingly important solutions as we strive for sustainable applications. Although viral infections are known to have significant impact on microbial turnover and nutrient cycling, viral dynamics have remained largely overlooked in these engineered communities. Predatory perturbations to the functional stability of these microbial biotechnology applications must be investigated in order to design more robust applications. In this study, we closely examine virus-microbe dynamics in a model microbial community used in a biotechnology application. Our findings suggest that viral dynamics change significantly with environmental conditions and that microbial immunity may play an important role in maintaining functional stability. We present this study as a comprehensive template for other researchers interested in exploring predatory dynamics in engineered microbial communities.

microbiology↗

bioRxiv2021

CANT-HYD: A curated database of phylogeny-derived Hidden Markov Models for annotation of marker genes involved in hydrocarbon degradation

Discovery of microbial hydrocarbon degradation pathways has traditionally relied on laboratory isolation and characterization of microorganisms. Although many metabolic pathways for hydrocarbon degradation have been discovered, the absence of tools dedicated to their annotation makes it difficult to identify the relevant genes and predict the hydrocarbon degradation potential of microbial genomes and metagenomes. Furthermore, sequence homology between hydrocarbon degradation genes and genes with other functions often results in misannotation. A tool that systematically identifies hydrocarbon metabolic potential is therefore needed. We present the Calgary approach to ANnoTating HYDrocarbon degradation genes (CANT-HYD), a database containing HMMs of 37 marker genes involved in anaerobic and aerobic degradation pathways of aliphatic and aromatic hydrocarbons. Using this database, we show that hydrocarbon metabolic potential is widespread in the tree of life and identify understudied or overlooked hydrocarbon degradation potential in many phyla. We also demonstrate scalability by analyzing large metagenomic datasets for the prediction of hydrocarbon utilization in diverse environments. To the best of our knowledge, CANT-HYD is the first comprehensive tool for robust and accurate identification of marker genes associated with aerobic and anaerobic hydrocarbon degradation.

bioinformatics↗