Browsing by Author "Ghosh, Preetam"

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    Comparative mangrove metagenome reveals global prevalence of heavy metals and antibiotic resistome across different ecosystems
    Imchen, Madangchanok; Kumavath, Ranjith; Barh, Debmalya; Vaz, Aline; Goes-Neto, Aristoteles; Tiwari, Sandeep; Ghosh, Preetam; Wattam, Alice R.; Azevedo, Vasco (Springer Nature, 2018-07-25)
    The mangrove ecosystem harbors a complex microbial community that plays crucial role in biogeochemical cycles. In this study, we analyzed mangrove sediments from India using de novo whole metagenome next generation sequencing (NGS) and compared their taxonomic and functional community structures to mangrove metagenomics samples from Brazil and Saudi Arabia. The most abundant phyla in the mangroves of all three countries was Proteobacteria, followed by Firmicutes and Bacteroidetes. A total of 1,942 genes were found to be common across all the mangrove sediments from each of the three countries. The mangrove resistome consistently showed high resistance to fluoroquinolone and acriflavine. A comparative study of the mangrove resistome with other ecosystems shows a higher frequency of heavy metal resistance in mangrove and terrestrial samples. Ocean samples had a higher abundance of drug resistance genes with fluoroquinolone and methicillin resistance genes being as high as 28.178% +/- 3.619 and 10.776% +/- 1.823. Genes involved in cobalt-zinc-cadmium resistance were higher in the mangrove (23.495% +/- 4.701) and terrestrial (27.479% +/- 4.605) ecosystems. Our comparative analysis of samples collected from a variety of habitats shows that genes involved in resistance to both heavy metals and antibiotics are ubiquitous, irrespective of the ecosystem examined.
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    Insight of Genus Corynebacterium: Ascertaining the Role of Pathogenic and Non-pathogenic Species
    Oliveira, Alberto; Oliveira, Leticia C.; Aburjaile, Flavia; Benevides, Leandro; Tiwari, Sandeep; Jamal, Syed B.; Silva, Arthur; Figueiredo, Henrique C. P.; Ghosh, Preetam; Portela, Ricardo W.; De Carvalho Azevedo, Vasco A.; Wattam, Alice R. (Frontiers, 2017-10-12)
    This review gathers recent information about genomic and transcriptomic studies in the Corynebacterium genus, exploring, for example, prediction of pathogenicity islands and stress response in different pathogenic and non-pathogenic species. In addition, is described several phylogeny studies to Corynebacterium, exploring since the identification of species until biological speciation in one species belonging to the genus Corynebacterium. Important concepts associated with virulence highlighting the role of Pld protein and Tox gene. The adhesion, characteristic of virulence factor, was described using the sortase mechanism that is associated to anchorage to the cell wall. In addition, survival inside the host cell and some diseases, were too addressed for pathogenic corynebacteria, while important biochemical pathways and biotechnological applications retain the focus of this review for non-pathogenic corynebacteria. Concluding, this review broadly explores characteristics in genus Corynebacterium showing to have strong relevance inside the medical, veterinary, and biotechnology field.
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    Searching for signatures across microbial communities: Metagenomic analysis of soil samples from mangrove and other ecosystems
    Imchen, Madangchanok; Kumavath, Ranjith; Barh, Debmalya; Avezedo, Vasco; Ghosh, Preetam; Viana, Marcus; Wattam, Alice R. (Springer Nature, 2017-08-18)
    In this study, we categorize the microbial community in mangrove sediment samples from four different locations within a vast mangrove system in Kerala, India. We compared this data to other samples taken from the other known mangrove data, a tropical rainforest, and ocean sediment. An examination of the microbial communities from a large mangrove forest that stretches across southwestern India showed strong similarities across the higher taxonomic levels. When ocean sediment and a single isolate from a tropical rain forest were included in the analysis, a strong pattern emerged with Bacteria from the phylum Proteobacteria being the prominent taxon among the forest samples. The ocean samples were predominantly Archaea, with Euryarchaeota as the dominant phylum. Principal component and functional analyses grouped the samples isolated from forests, including those from disparate mangrove forests and the tropical rain forest, from the ocean. Our findings show similar patterns in samples were isolated from forests, and these were distinct from the ocean sediment isolates. The taxonomic structure was maintained to the level of class, and functional analysis of the genes present also displayed these similarities. Our report for the first time shows the richness of microbial diversity in the Kerala coast and its differences with tropical rain forest and ocean microbiome.