Publications by authors named "Chayan Roy"

Trans-Himalayan hot spring waters rich in boron, chlorine, sodium and sulfur (but poor in calcium and silicon) are known based on PCR-amplified 16S rRNA gene sequence data to harbor high diversities of infiltrating bacterial mesophiles. Yet, little is known about the community structure and functions, primary productivity, mutual interactions, and thermal adaptations of the microorganisms present in the steaming waters discharged by these geochemically peculiar spring systems. We revealed these aspects of a bacteria-dominated microbiome (microbial cell density ~8.

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The bacterial diseases black leg and soft rot in potatoes cause heavy losses of potatoes worldwide. Bacteria within the genus Pectobacteriaceae are the causative agents of black leg and soft rot. The use of antibiotics in agriculture is heavily regulated and no other effective treatment currently exists, but bacteriophages (phages) have shown promise as potential biocontrol agents.

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Bacteriophages are viral agents that infect and replicate within bacterial cells. Despite the increasing importance of phage ecology, environmental phages-particularly those targeting phyllosphere-associated bacteria-remain underexplored, and current genomic databases lack high-quality phage genome sequences linked to specific environmentally important bacteria, such as the ubiquitous sphingomonads. Here, we isolated three novel phages from a Danish wastewater treatment facility.

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High temperature growth/survival was revealed in a phylogenetic relative (SMMA_5) of the mesophilic isolated from the 78 to 85°C water of a Trans-Himalayan sulfur-borax spring. After 12 h at 50°C, or 45 min at 70°C, in mineral salts thiosulfate (MST) medium, SMMA_5 retained ~2% colony forming units (CFUs), whereas comparator had 1.5% and 0% CFU left at 50°C and 70°C, respectively.

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Fusobacterium necrophorum is a Gram-negative, filamentous anaerobe prevalent in the mucosal flora of animals and humans. It causes necrotic infections in cattle, resulting in a substantial economic impact on the cattle industry. Although infection severity and management differ within F.

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Background: Vector-borne diseases (VBDs) impact both human and veterinary medicine and pose special public health challenges. The main bacterial vector-borne pathogens (VBPs) of importance in veterinary medicine include Anaplasma spp., Bartonella spp.

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Article Synopsis
  • Accurate detection of vector-borne pathogens (VBPs) is crucial due to the increasing cases in humans and animals, and current PCR assays face challenges in identifying low levels of these pathogens in blood samples.
  • This study examined the effectiveness of a microbial enrichment kit to boost VBP detection in canine blood by depleting host DNA, using samples from dogs infected with specific pathogens.
  • Results showed that the microbial concentrating kit did not enhance VBP detection but did lower host DNA presence, suggesting that more research is needed to find better methods for improving VBP enrichment before testing.
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To understand SARS-CoV-2 microevolution, this study explored the genome-wide frequency, gene-wise distribution, and molecular nature of all point-mutations detected across its 71,703 RNA-genomes deposited in GISAID till 21 August 2020. Globally, nsp1/nsp2 and orf7a/orf3a were the most mutation-ridden non-structural and structural genes respectively. Phylogeny of 4618 spatiotemporally-representative genomes revealed that entities belonging to the early lineages are mostly spread over Asian countries, including India, whereas the recently-derived lineages are more globally distributed.

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The ecology of aerobic microorganisms is never explored in marine oxygen minimum zone (OMZ) sediments. Here we reveal aerobic bacterial communities along ∼3 m sediment-horizons of the eastern Arabian Sea OMZ. Sulfide-containing sediment-cores retrieved from 530 mbsl (meters beneath the sea-level) and 580 mbsl were explored at 15-30 cm intervals, using metagenomics, pure-culture-isolation, genomics and metatranscriptomics.

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Little is known about life in the boron-rich hot springs of Trans-Himalayas. Here, we explore the geomicrobiology of a 4438-m-high spring which emanates ~70 °C-water from a boratic microbialite called Shivlinga. Due to low atmospheric pressure, the vent-water is close to boiling point so can entropically destabilize biomacromolecular systems.

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A major function of the gut microbiota is to provide colonization resistance, wherein pathogens are inhibited or suppressed below infectious levels. However, the fraction of gut microbiota required for colonization resistance remains unclear. We used culturomics to isolate a gut microbiota culture collection comprising 1,590 isolates belonging to 102 species.

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This study characterizes four KPC-2-producing Klebsiella pneumoniae isolates from neonates belonging to a single sequence type 147 (ST147) in relation to carbapenem resistance and explores probable mechanisms of differential colistin resistance among the clonal cluster. Whole genome sequencing (WGS) revealed that the isolates were nearly 100% identical and harbored resistance genes (bla,,,,,, oqxA, oqxB, qnrB1, fosA, arr-2, sul1, aacA4, aac(6')Ib-cr, aac(6')Ib), and several virulence genes. bla was the only carbapenem-resistant gene found, bracketed between ISKpn7 and ISKpn6 of Tn4401b on a non-conjugative IncFII plasmid.

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All cultivated members of the phylum Chlorobi are classified under the two classes Chlorobia and Ignavibacteria. The recently-reported, uncultivated genome-species of Chlorobi have not suggested any alteration in the dichotomy of the two classes, but have hypothesized the existence of a distinct, aerobic and photoheterotrophic, order/family level lineage within Chlorobia, which otherwise was considered to be a monophyletic group of anaerobic sulfur-photolithoautotrophs. Here we report the discovery of a novel population genome bin (named Chlorobi-445) from the combined metagenomes of three spatially-contiguous but visually-distinct microbial mats growing along the 65-41 °C hydrothermal gradient of a boron-rich microbialite spring located in the Puga geothermal area of Eastern Ladakh, India.

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NaCl-saturated brines such as saltern crystalliser ponds, inland salt lakes, deep-sea brines and liquids-of-deliquescence on halite are commonly regarded as a paradigm for the limit of life on Earth. There are, however, other habitats that are thermodynamically more extreme. Typically, NaCl-saturated environments contain all domains of life and perform complete biogeochemical cycling.

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Biogeochemistry of oxygen minimum zone (OMZ) sediments, which are characterized by high input of labile organic matter, have crucial bearings on the benthic biota, gas and metal fluxes across the sediment-water interface, and carbon-sulfur cycling. Here we couple pore-fluid chemistry and comprehensive microbial diversity data to reveal the sedimentary carbon-sulfur cycle across a water-depth transect covering the entire thickness of eastern Arabian Sea OMZ, off the west coast of India. Geochemical data show remarkable increase in average total organic carbon content and aerial sulfate reduction rate (J) in the sediments of the OMZ center coupled with shallowing of sulfate methane transition zone and hydrogen sulfide and ammonium build-up.

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Here, we present the draft genome sequence of Geobacillus thermoleovorans strain N7 (MCC 3175), isolated from Paniphala Hot Spring, West Bengal, India, which contains genes that encode several industrially and medically important thermostable enzymes like neutral protease, xylose isomerase, rhamnogalacturonan acetylesterase, nitrate and nitrite reductase, l-asparaginase, glutaminase, and RNase P.

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Here, we present the draft genome of Haladaptatus sp. strain R4, a halophilic archaea that produces an orange-pink pigment and is capable of growing in a wide salinity range. The genome assembly shows genes for arsenic resistance, siderophore production, trehalose and glycine betaine biosynthesis, uptake and transporters of sodium, potassium, and chloride ions.

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Here we report the draft genome sequence of Meiothermus taiwanensis strain RP (MCC 2966), isolated from the Paniphala hot spring of India, which contains genes encoding for enzymes of the methyl erythritol 4-phosphate (MEP) pathway of isoprenoid biosynthesis and carotenoid backbone synthesis.

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Exploration of the aquatic microbiota of several circum-neutral (6.0-8.5 pH) mid-temperature (55-85°C) springs revealed rich diversities of phylogenetic relatives of mesophilic bacteria, which surpassed the diversity of the truly-thermophilic taxa.

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To elucidate how geothermal irregularities affect the sustainability of high-temperature microbiomes we studied the synecological dynamics of a geothermal microbial mat community (GMMC) vis-à-vis fluctuations in its environment. Spatiotemporally-discrete editions of a photosynthetic GMMC colonizing the travertine mound of a circum-neutral hot spring cluster served as the model-system. In 2010 a strong geyser atop the mound discharged mineral-rich hot water, which nourished a GMMC continuum from the proximal channels (PC) upto the slope environment (SE) along the mound's western face.

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This study elucidates the genomic basis of the evolution of pathogens alongside free-living organisms within the family Alcaligenaceae of Betaproteobacteria. Towards that end, the complete genome sequence of the sulfur-chemolithoautotroph Tetrathiobacter kashmirensis WT001(T) was determined and compared with the soil isolate Achromobacter xylosoxidans A8 and the two pathogens Bordetella bronchiseptica RB50 and Taylorella equigenitalis MCE9. All analyses comprehensively indicated that the RB50 and MCE9 genomes were almost the subsets of A8 and WT001(T), respectively.

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The facultatively sulfur-oxidizing chemolithoautotrophic alphaproteobacterium Pseudaminobacter salicylatoxidans KCT001 (MTCC 7265) belongs to the family Phyllobacteriaceae of the order Rhizobiales. Analysis of its genome offers valuable insight into the adaptive specializations and evolution of free-living soil bacteria that are phylogenetically closely related to symbiotic and invasive rhizobacteria.

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