Browsing by Author "Singh, Deepak K."

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    Purification, characterization and assessment of stability, reactive oxygen species scavenging and antioxidative potentials of mycosporine-like amino acids (MAAs) isolated from cyanobacteria
    (Springer Science and Business Media B.V., 2022) Singh, Deepak K.; Pathak, Jainendra; Pandey, Abha; Rajneesh; Singh, Vidya; Sinha, Rajeshwar P.
    Mycosporine-like amino acids (MAAs) were characterized and their stability and free radical scavenging potentials were investigated in Anabaena sp. HKAR-7 and Fischerella sp. AR-5. UV/VIS absorption spectroscopy, high performance liquid chromatography and electrospray ionization-mass spectrometry showed occurrence of diverse forms of MAAs at retention time (RT) 1.16 (shinorine), 2.18 (mycosporine glycine-310) and 3.14�min (palythinol) with UV?max 310, 332 and 334�nm respectively, in Fischerella sp. when contrasted with Anabaena sp. (prominent peak at RT 3.21�min (porphyra 334; P-334) with UV?max 334�nm. MAAs showed dose-dependent in vitro antioxidative and in vivo reactive oxygen species (ROS) scavenging potentials. The MAA P-334 was used against strong allelochemical pyrogallic acid in Anabaena sp. P-334 reducing the negative impacts brought about by ROS, in this way, the malondialdehyde content and unwinding of dsDNA were similarly low. This clarifies the role of MAA P-334 against cell�s ROS under studied stressed conditions. � 2022, The Author(s), under exclusive licence to Springer Nature B.V.
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    Ultraviolet radiation and salinity-induced physiological changes and scytonemin induction in cyanobacteria isolated from diverse habitats
    (AMG Transcend Association, 2022) Pathak, Jainendra; Kumar, Deepak; Singh, Deepak K.; Ahmed, Haseen; Kannaujiya, Vinod K.; Sinha, Rajeshwar P.
    Enhanced ultraviolet radiation (UVR) in the atmosphere and increased salinity of soils and water adversely affect photoautotrophs' productivity. Several researchers have focussed on the use of non-arable or brackish environments for growing strains suitable for the production of value-added products along with biofuels. In this regard, cyanobacteria serve as good model organisms as they can survive and sustain themselves in habitats characterized by high UV influx and changing salinities. Thus, these photoautotrophs can help understand the complex physiological processes and adaptations occurring in higher plants growing in stressed environments of salinity and UVR. In the present investigation, cumulative effects of salinity (NaCl: 50, 100, and 200 mM), photosynthetically active radiation (PAR), and UVR have been studied in terms of the reactive oxygen species (ROS) generation, total protein content, phycobiliproteins profile, and induction of scytoneminin in the two cyanobacteria isolated from different habitats. Production of ROS increased after PAR+UV-A+UV-B, PAR+UV-A, and PAR exposure, and maximum generation occurred in the samples treated with 200 mM NaCl. Total protein content and phycobiliproteins profile was severely affected by these stresses. The maximum induction of scytonemin occurred in the cultures with 200 mM of NaCl and PAR+UV-A+UV-B exposure for 72 h. Our results indicate that Scytonema sp. could serve as a potential candidate for bioremediation of saline soils along with the production of value-added metabolite scytonemin. � 2021 by the authors.