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Jha D.K.,National Institute of Ocean Technology ESSO NIOT | Jha D.K.,Andaman and Nicobar Center for Ocean Science and Technology | Devi M.P.,Bharathidasan University | Vidyalakshmi R.,Bharathidasan University | And 3 more authors.
Marine Pollution Bulletin | Year: 2015

Seawater samples at 54 stations in the year 2011-2012 from Chidiyatappu, Port Blair, Rangat and Aerial Bays of Andaman Sea, have been investigated in the present study. Datasets obtained have been converted into simple maps using coastal water quality index (CWQI) and Geographical Information System (GIS) based overlay mapping technique to demarcate healthy and polluted areas. Analysis of multiple parameters revealed poor water quality in Port Blair and Rangat Bays. The anthropogenic activities may be the likely cause for poor water quality. Whereas, good water quality was witnessed at Chidiyatappu Bay. Higher CWQI scores were perceived in the open sea. However, less exploitation of coastal resources owing to minimal anthropogenic activity indicated good water quality index at Chidiyatappu Bay. This study is an attempt to integrate CWQI and GIS based mapping technique to derive a reliable, simple and useful output for water quality monitoring in coastal environment. © 2015 Elsevier Ltd. Source


Dheenan P.S.,Andaman and Nicobar Center for Ocean Science and Technology | Jha D.K.,National Institute of Ocean Technology ESSO NIOT | Das A.K.,Andaman and Nicobar Center for Ocean Science and Technology | Vinithkumar N.V.,Andaman and Nicobar Center for Ocean Science and Technology | And 2 more authors.
Environmental Pollution | Year: 2016

Urbanization of coastal areas in recent years has driven us to consider a new approach for visually delineating sites that are contaminated with fecal bacteria (FB) in the coastal waters of the Andaman Islands in India. Geo-spatial analysis demarcated harbor, settlement, and freshwater/discharge influenced zones as hot spots for FB, while the open sea was demarcated as a cold spot. The land use types, such as developed and agriculture, with more anthropogenic activities increasing the FB counts while open sea showed the least FB. Box whisker plot indicated an increasing FB trend in the coastal waters during monsoon. Furthermore, principal component analysis revealed 67.35%, 78.62% and 70.43% of total variance at Port Blair, Rangat and Aerial bays, respectively. Strong factor loading was observed for depth (0.95), transparency (0.93), dissolved oxygen (0.93) and fecal streptococci (0.85). Distance proximity analysis revealed that fecal contaminations diluted significantly (P < 0.05) at the distance of 2.1 km toward the deeper or open sea water. This study demonstrates the effectiveness of an integrated approach in identifying the sources of fecal contamination and thus helping in better monitoring and management of coastal waters. © 2016 Elsevier Ltd. All rights reserved. Source


Meena B.,National Institute of Ocean Technology ESSO NIOT | Anburajan L.,National Institute of Ocean Technology ESSO NIOT | Dheenan P.S.,National Institute of Ocean Technology ESSO NIOT | Begum M.,National Institute of Ocean Technology ESSO NIOT | And 3 more authors.
Bioprocess and Biosystems Engineering | Year: 2015

Studies were carried out for the optimization and production of novel extracellular glutaminase-free l-asparaginase from Nocardiopsis alba NIOT-VKMA08. Among the tested carbon and nitrogen sources, maximum l-asparaginase production was observed with a combination of l-asparagine and maltose (1.5 %) and twofold increase in yield (18.47 IU mL-1) was observed with newly optimized NIOT-asparaginase medium. Activity of the purified enzyme was moderately inhibited by various divalent cations and thiol group blocking reagents, with K m and V max of 0.127 mM and 5.50 U μg-1. Optimum pH and temperature of purified l-asparaginase for the hydrolysis of l-asparagine was 8.0 and 37 °C, respectively. The enzyme inhibited polyacrylamide formation in 10 % solution and it was very specific for its natural substrate l-asparagine. Partial glutaminase activity was not detected, which could reduce the possibility of side effects during cancer therapy. l-Asparaginase biosynthesis gene (ansA) was cloned and transformed in E. coli JM109. The ansA gene sequence reported in this study contains several base substitutions with that of reported sequences in GenBank, resulting in altered amino acid sequences of the translated protein. © 2014 Springer-Verlag Berlin Heidelberg. Source


Meena B.,National Institute of Ocean Technology ESSO NIOT | Anburajan L.,National Institute of Ocean Technology ESSO NIOT | Vinithkumar N.V.,National Institute of Ocean Technology ESSO NIOT | Shridhar D.,Ocean Science and Technology for Islands Group | And 3 more authors.
Gene | Year: 2016

l-Asparaginase is an antineoplastic agent that selectively reduces the level of l-asparagine in blood and diminishes the proliferation of cancerous cells. Studies were carried out on the cloning and heterologous expression of l-asparaginase biosynthesis gene (ansA) from Nocardiopsis alba NIOT-VKMA08 to achieve the stable inducible system that overproduces the glutaminase-free recombinant l-asparaginase. Overexpression of recombinant l-asparaginase was achieved with an optimized final concentration of 1.5. mM of isopropyl-β-d-thiogalactoside (IPTG) and the enzyme was expressed as a soluble protein. The recombinant enzyme was purified using nickel-nitrilotriacetic acid (Ni-NTA) chromatography and the purified enzyme disclosed an elevated level of asparaginase activity (158.1. IU/mL). Optimum pH and temperature of the purified l-asparaginase for the hydrolysis of l-asparagine were 8.0 and 37. °C and it was very specific for its natural substrate, l-asparagine. Detailed studies were carried out on the kinetics of enzyme reaction, catalytic activity, temperature and ionic strength and the thermostability of the l-asparaginase enzyme. The functional characterisation of the recombinant l-asparaginase was studied through Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), in silico sequence analysis and protein structural modelling. Glutaminase activity was not detected in the recombinant l-asparaginase, which could reduce the probable side effects during leukaemia therapy. © 2016. Source

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