Browsing by Author "Kundu, Pushpendu"

Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Biogeochemistry of the antarctic coasts: Implications for biodiversity and climate change
    (Wiley Blackwell, 2022-04-01T00:00:00) Karayakath, Amrutha; Pattanaik, Jitendra K.; Saini, Khem C.; Kundu, Pushpendu; Bast, Felix
    Notwithstanding its largely lifeless appearance, Antarctica hosts considerable biodiversity and ecosystem (trophic-level) complexity. Antarctic soils, ice-covered areas, coastal regions, and the surrounding Southern Ocean contributes to this biodiversity. However, studies related to the number of species present, how and where they are located and their influence on the ecosystem processes are still scarce. Biodiversity and biogeochemical cycles often coincide with climate change studies. Photosynthetic carbon fixation by phytoplanktons in the Antarctic coasts influences the atmospheric CO2 levels. On a geological timescale, such processes determine the climate. In this chapter, studies on Essential Ocean Variables and elemental cycles in Antarctica are reviewed to understand the biogeochemistry of the coast of Antarctica, and how these parameters and cycles influence the different coastal features of Antarctica. In the recent past, Antarctica has experienced a rapid rate of warming that in turn has threatened its biodiversity. The effects of climate change on biogeochemical parameters and their further consequences are therefore discussed here. The second half of this chapter deals with the prokaryotic as well as eukaryotic microbial diversities of Antarctica, and the implications they hold for climate change. � 2022 John Wiley & Sons, Inc. All rights reserved.
  • No Thumbnail Available
    Item
    First report of Planomicrobium okeanokoites associated with Himantothallus grandifolius (Desmarestiales, Phaeophyta) from Southern Hemisphere
    (Public Library of Science, 2023-04-14T00:00:00) Chand Saini, Khem; Gupta, Kriti; Sharma, Sheetal; Gautam, Ajay K.; Shamim, Samrin; Mittal, Divya; Kundu, Pushpendu; Bast, Felix
    Gram-positive, aerobic, motile, rod-shaped, mesophilic epiphytic bacterium Planomicrobium okeanokoites was isolated from the surface of endemic species Himantothallus grandifolius in Larsemann Hills, Eastern Antarctica. The diversity of epiphytic bacterial communities living on marine algae remains primarily unexplored; virtually no reports from Antarctic seaweeds. The present study used morpho-molecular approaches for the macroalgae and epiphytic bacterium characterization. Phylogenetic analysis was performed using mitochondrial genome encoded COX1 gene; chloroplast genome encodes rbcL; nuclear genome encoded large subunit ribosomal RNA gene (LSU rRNA) for Himantothallus grandifolius and ribosomal encoded 16S rRNA for Planomicrobium okeanokoites. Morphological and molecular data revealed that the isolate is identified as Himantothallus grandifolius, which belongs to Family Desmarestiaceae of Order Desmarestiales in Class Phaeophyceae showing 99.8% similarity to the sequences of Himantothallus grandifolius, from King George Island, Antarctica (HE866853). The isolated bacterial strain was identified on the basis of chemotaxonomic, morpho-phylogenetic, and biochemical assays. A phylogenetic study based on 16S rRNA gene sequences revealed that the epiphytic bacterial strain SLA-357 was closest related to the Planomicrobium okeanokoites showing 98.7% sequence similarity. The study revealed the first report of this species from the Southern Hemisphere to date. Also, there has been no report regarding the association between the Planomicrobium okeanokoites and Himantothallus grandifolius; however, there are some reports on this bacterium isolated from sediments, soils, and lakes from Northern Hemisphere. This study may open a gateway for further research to know about the mode of interactions and how they affect the physiology and metabolism of each other. � 2023 Saini et al.
  • No Thumbnail Available
    Item
    First report of Planomicrobium okeanokoites associated with Himantothallus grandifolius (Desmarestiales, Phaeophyta) from Southern Hemisphere
    (Public Library of Science, 2023-04-14T00:00:00) Chand Saini, Khem; Gupta, Kriti; Sharma, Sheetal; Gautam, Ajay K.; Shamim, Samrin; Mittal, Divya; Kundu, Pushpendu; Bast, Felix
    Gram-positive, aerobic, motile, rod-shaped, mesophilic epiphytic bacterium Planomicrobium okeanokoites was isolated from the surface of endemic species Himantothallus grandifolius in Larsemann Hills, Eastern Antarctica. The diversity of epiphytic bacterial communities living on marine algae remains primarily unexplored; virtually no reports from Antarctic seaweeds. The present study used morpho-molecular approaches for the macroalgae and epiphytic bacterium characterization. Phylogenetic analysis was performed using mitochondrial genome encoded COX1 gene; chloroplast genome encodes rbcL; nuclear genome encoded large subunit ribosomal RNA gene (LSU rRNA) for Himantothallus grandifolius and ribosomal encoded 16S rRNA for Planomicrobium okeanokoites. Morphological and molecular data revealed that the isolate is identified as Himantothallus grandifolius, which belongs to Family Desmarestiaceae of Order Desmarestiales in Class Phaeophyceae showing 99.8% similarity to the sequences of Himantothallus grandifolius, from King George Island, Antarctica (HE866853). The isolated bacterial strain was identified on the basis of chemotaxonomic, morpho-phylogenetic, and biochemical assays. A phylogenetic study based on 16S rRNA gene sequences revealed that the epiphytic bacterial strain SLA-357 was closest related to the Planomicrobium okeanokoites showing 98.7% sequence similarity. The study revealed the first report of this species from the Southern Hemisphere to date. Also, there has been no report regarding the association between the Planomicrobium okeanokoites and Himantothallus grandifolius; however, there are some reports on this bacterium isolated from sediments, soils, and lakes from Northern Hemisphere. This study may open a gateway for further research to know about the mode of interactions and how they affect the physiology and metabolism of each other. � 2023 Saini et al.
  • No Thumbnail Available
    Item
    Molecular data reveals two new species of Hypnea (Cystocloniaceae, Rhodophyta) from India: Hypnea indica sp. Nov. And Hypnea bullata sp. Nov.
    (De Gruyter Open Ltd, 2021-03-22T00:00:00) Kundu, Pushpendu; Bast, Felix
    We used three molecular markers (COI-5P, rbcL and UPA) to investigate the diversity of Hypnea spp., an economically important red algal genus, collected from India. Our concatenated tree (COI-5P and rbcL) supported the monophyly of two new species, Hypnea indica sp. nov. and Hypnea bullata sp. nov. H. indica diverged from its closest two sister species, Hypnea cervicornis and Hypnea tenuis (by 15.9 and 11.2%, respectively, in COI-5P; and 3.4 and 3.2% in rbcL). We describe H. indica as a new species characterised by an erect, percurrent main axis with spinelike branchlets in acute angles, straight and forked apices, axial cells surrounded by large periaxial cells or two cells similar in size to the axial cell, and the presence of lenticular thickening in the cross-section of the thallus. H. bullata diverged from its closest sister species, Hypnea brasiliensis (by 10.9% in COI-5P and 3.3% in rbcL). H. bullata is characterized by a prostrate thallus up to 1.5 cm in height, highly anastomosed, with an axial cell surrounded by similar sized, or smaller, periaxial cells, tetrasporangia present near the base of branchlets, and the presence of lenticular thickening. � 2021 De Gruyter. All rights reserved.
  • No Thumbnail Available
    Item
    Molecular data reveals two new species of Hypnea (Cystocloniaceae, Rhodophyta) from India: Hypnea indica sp. Nov. And Hypnea bullata sp. Nov.
    (De Gruyter Open Ltd, 2021-03-22T00:00:00) Kundu, Pushpendu; Bast, Felix
    We used three molecular markers (COI-5P, rbcL and UPA) to investigate the diversity of Hypnea spp., an economically important red algal genus, collected from India. Our concatenated tree (COI-5P and rbcL) supported the monophyly of two new species, Hypnea indica sp. nov. and Hypnea bullata sp. nov. H. indica diverged from its closest two sister species, Hypnea cervicornis and Hypnea tenuis (by 15.9 and 11.2%, respectively, in COI-5P; and 3.4 and 3.2% in rbcL). We describe H. indica as a new species characterised by an erect, percurrent main axis with spinelike branchlets in acute angles, straight and forked apices, axial cells surrounded by large periaxial cells or two cells similar in size to the axial cell, and the presence of lenticular thickening in the cross-section of the thallus. H. bullata diverged from its closest sister species, Hypnea brasiliensis (by 10.9% in COI-5P and 3.3% in rbcL). H. bullata is characterized by a prostrate thallus up to 1.5 cm in height, highly anastomosed, with an axial cell surrounded by similar sized, or smaller, periaxial cells, tetrasporangia present near the base of branchlets, and the presence of lenticular thickening. � 2021 De Gruyter. All rights reserved.