National Institute of Oceanography of India

Goa, India

National Institute of Oceanography of India

Goa, India
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Majik M.S.,National Institute of Oceanography of India | Parvatkar P.T.,National Institute of Oceanography of India
Current Topics in Medicinal Chemistry | Year: 2014

The bacterial biofilms and the emergence of multiple drug resistance have become a major threat for current medical treatment of nosocomial infections. It has been estimated that about 65-80% of microbial infections in the developed countries are associated with biofilms. Given the prominence of biofilms in infectious diseases, increasing efforts toward the development of small molecules that will modulate bacterial biofilm development and maintenance is on the rise. Till date, marine natural products have shown a tremendous potential as pharma leads and also given new skeletons which would be used as biofilm/QS inhibitors. Medically relevant biofilm forming bacteria such as Pseudomonas aeruginosa which is most frequently isolated bacteria in nosocomial infection is believed to be a model organism for biofilm studies. Hence, in this review, we have highlighted the development of small molecules that inhibit and/or disperse bacterial biofilms of P. aeruginosa in particular. Additionally, the rational design approaches as well as synthetic methodologies along with biological studies has been accounted in this article. © 2014 Bentham Science Publishers.

Agency: European Commission | Branch: FP7 | Program: CP-IP | Phase: KBBE-2009-3-2-01 | Award Amount: 7.90M | Year: 2010

Biodiversity in the seas is only partly explored, although marine organisms are excellent sources for many industrial products. Through close co-operation between industrial and academic partners, the MAREX project will collect, isolate and classify marine organisms, such as micro- and macroalgae, cyanobacteria, sea anemones, tunicates and fish from the Atlantic, Pacific and Indian Oceans as well as from the Mediterranean, Baltic and Arabian Seas. Extracts and purified compounds of these organisms will be studied for several therapeutically and industrially significant biological activities, including anticancer, anti-inflammatory, antiviral and anticoagulant activities by applying a wide variety of screening tools, as well as for ion channel/receptor modulation and plant growth regulation. Chromatographic isolation of bioactive compounds will be followed by structural determination. Sustainable cultivation methods for promising organisms, and biotechnological processes for selected compounds will be developed, as well as biosensors for monitoring the target compounds. The work will entail sustainable organic synthesis of selected active compounds and new derivatives, and development of selected hits to lead compounds. The project will expand marine compound libraries. MAREX innovations will be targeted for industrial product development in order to improve the growth and productivity of European marine biotechnology. MAREX aims at a better understanding of environmentally conscious sourcing of marine biotechnology products and increased public awareness of marine biodiversity and potential. Finally, MAREX is expected to offer novel marine-based lead compounds for European industries and strengthen their product portfolios related to pharmaceutical, nutraceutical, cosmetic, agrochemical, food processing, material and biosensor applications.

Fernandes L.,National Institute of Oceanography of India
Estuarine, Coastal and Shelf Science | Year: 2011

Mandovi estuary is a tropical estuary strongly influenced by the southwest monsoon. In order to understand, sources and fate of particulate organic nitrogen, suspended particulate matter (SPM) collected from various locations, was analyzed for particulate organic carbon (POC) and particulate organic nitrogen (PON), δ13CPOC, total hydrolysable amino acid enantiomers (l- and d- amino acids) concentration and composition δ13CPOC values were depleted (-32 to -25‰) during the monsoon and enriched (-29.6 to -21‰) in the pre-monsoon season implying that OM was derived from terrestrial and marine sources during the former and latter season, respectively. The biological indicators such as C/N ratio, d-amino acids, THAA yields and degradation indices (DI) indicate that the particulate organic matter (POM) was relatively more degraded during the monsoon season. Conversely, during the pre-monsoon, the biological indicators indicated the presence of relatively fresh and labile POM derived from autochthonous sources. Amino acids such as alanine, aspartic acid, leucine, serine, arginine, and threonine in monsoon and glutamic acid, glycine, valine, lysine, and isoleucine in pre-monsoon were relatively abundant. Presence of bacterial biomarker, d-amino acids in the SPM of the estuary during both the seasons signifies important contribution of bacteria to the estuarine detrital ON pool. Based on d-amino acid yields, bacterial OM accounted for 16-34% (23.0 ± 6.7%) of POC and 29-75% (47.9 ± 18.7%) of PON in monsoon, and 30-78% (50.0 ± 15%) of POC and 34-79% (51.2 ± 13.3%) of the PON in pre-monsoon in the estuary. Substantial contribution of bacterial-N to PON indicates nitrogen (N) enrichment on terrestrial POM during the monsoon season. Transport of terrestrial POM enriched with bacterial OM to the coastal waters is expected to influence coastal productivity and ecosystem functioning during the monsoon season. © 2011 Elsevier Ltd.

Parvatkar P.T.,National Institute of Oceanography of India | Parameswaran P.S.,National Institute of Oceanography of India | Tilve S.G.,Goa University
Chemistry - A European Journal | Year: 2012

Heterocyclic scaffolds represent the key structural subunits of many biologically active compounds. Over the last few years iodine-mediated reactions have been extensively studied due to their low cost and eco-friendliness. This Review covers advances in the field of iodine-mediated synthesis of heterocyclic compounds since 2006, especially with an emphasis on mechanisms of ring formation. In this article, syntheses of different heterocycles are classified based on the manipulation of functional groups. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Imchen T.,National Institute of Oceanography of India
PLoS ONE | Year: 2012

The recruitment potential and the ability of Ulva flexuosa Wulfen zoospores to survive darkness were tested under different conditions in the present study. The dark preserved zoospore was cultured under a two-factor experimental design to test the effect of salinity and nitrate, effect of salinity and phosphate, effect of light and salinity, and effect of light and phosphate. The recruitment (germination and growth) of zoospores was significantly affected by light and salinity. The nitrate concentration of 20 μmol.l -1 was found to initiate the process of germination and its subsequent growth and, its effect appeared greatest under 25 psu condition. While nitrate enhances the growth of biomass more than phosphate, both show a positive interactive effect on biomass increase when crossed with salinity. The combined effect of 25 psu salinity and 8 μmol.l -1 phosphate exhibited higher biomass growth. There was a significant effect of light and salinity on the biomass of zoospore, though there was no significant interaction between the two factors. There was an increase in biomass of growing zoospores to increase in light intensity and 80 μmol.m -2.s -1 of light intensity was considered optimal. Similarly, high light intensity condition favored higher biomass growth and there was significant interaction between light (80 μmol. m -2. s -1) and phosphate (4 μmol. l -1) in high salinity (35 psu) condition. The result of this study showed that dark preserved zoospores of U. flexuosa have the potential for recruitment and it gives us an understanding how different factors play a role in the process of recruitment. © 2012 Temjensangba Imchen.

Chakraborty P.,National Institute of Oceanography of India
Journal of Geochemical Exploration | Year: 2012

Kinetic and sequential extraction methods were used to investigate chemical speciation and distribution of Co, Ni, and Cu in the estuarine and coastal sediments collected from the central east coast of India. The kinetic (single) extraction study provided a chemically significant description of the kinetics of metals-sediment interactions and correctly predicted the influences of ligand field stabilization energy (LFSE) and water exchange rate (k -w) on the dissociation rate constants of metals-sediments complexes in the natural systems. The results consistently demonstrate that the fast (k d1) and medium fast (k d2) dissociation rate constants of the 3d transition metals complexes in the estuarine and coastal sediments follow the trend as predicted from the LFSEs (weak field) (k d 1,2,Co(II) d 7>k d 1,2, Ni(II) d 8>k d 1,2, Cu(II) d 9). However, a higher rate coefficient of water exchange (k -w) of Cu (II) helps them to form more strong inert complexes than predicted from its LFSE alone. Sequential extraction method was used to fractionate these metals depending upon their association with different phases in the studied sediments. The comparison and statistical analysis of the fractionation data obtained by two independent methods indicate that the transition metals formed strong complexes with the organic matter present in the sediments. However, Cu undergoes strong complexation reaction with organic matter within the sediments followed by Ni and Co. This study suggests that the non-residual fractions (obtained from sequential extraction study) may overestimate the bioavailable fraction of metals in a system. © 2012 Elsevier B.V.

Vinothkumar S.,National Institute of Oceanography of India | Parameswaran P.S.,National Institute of Oceanography of India
Biotechnology Advances | Year: 2013

Structures and properties of promising marine anti-cancer, anti-inflammation and anti-infectious (HIV, HSV, malaria, leishmania) compounds reported during 2008-2011 are discussed. Wherever possible, attempts have also been made to highlight their possible biogenesis or structure-activity relationships (SAR). Since the stress is on identifying and short-listing potential drug molecules, this review is restricted to only those compounds exhibiting promising in vitro activity, the arbitrary cut off being IC50<15μM, reported during the above period. © 2013 Elsevier Inc.

Diffusion coefficients of Cd-humate complexes are dependent on pH and [Cd]/[Humic] Acid (HA)] ratio in a Cd-HA system. These two factors mainly control the mass transport and complexation kinetics of Cd that may influence bioavailability and toxicity of Cd species in environmental systems. Determination of diffusion coefficients of Cd-HA systems by Scanned stripping voltammetry and dynamic light scattering techniques can provide a better understanding of the systems and can be very useful for extracting other speciation parameters of the systems. This study revealed that Cd2+ ion along with small dynamic Cd complexes was predominantly present in a Cd-HA system at pH 5 with high diffusion coefficients. HA molecules were in aggregated form at pH 5. However, HA molecules were in disaggregated form at pH 6 and concentrations of Cd2+ ion and small Cd-dynamic complexes decreased with a decrease in diffusion coefficients of Cd complexes at this pH due to formation of Cd-humate complexes. No further decrease in the hydrodynamic radii of HA was observed with the increase of pH from 6 to 7. The Cd-humate system partially lost its lability at pH 7. Conditional stability constants were calculated for Cd-humate complexes by combining the diffusion coefficient data obtained by two techniques. The log K values calculated in this study are in good agreement with the data available from the literature. © 2009 Elsevier B.V. All rights reserved.

Roy R.,National Institute of Oceanography of India
Estuarine, Coastal and Shelf Science | Year: 2010

Halocarbons released from oceans are known to be important in the atmospheric processes. Their abundance in seawater is influenced by water column conditions and phytoplankton community. In the present study halocarbon abundances together with pigment composition were monitored in the coastal waters of the central eastern Arabian Sea. Short-term variability for the period December 2005-March 2007 was studied for chlorinated hydrocarbons (CHCl3, CCl4) and bromocarbons (CH2Br2 and CHBr3) for the first time in the Arabian Sea. Variability in pigments was used to understand the influence of phytoplankton community composition on halocarbon concentrations in this region. Halocarbons and phytoplankton pigments showed strong short-term variability, with maximal values generally associated with southwest (summer) monsoon high productivity. Decreased chlorocarbon abundances in sub-surface layers indicate their possible consumption under oxygen deficient conditions, particularly during the summer monsoon and Fall-Intermonsoon periods. Halocarbon abundances were in the order: CHCl3, CH2Br2, CHBr3 and CCl4. The CHCl3 showed significant positive relationship with fucoxanthin (r = 0.93, p = 0.001, n = 155) suggesting the importance of diatoms and prymnesiophytes in the Arabian Sea. Among the phytoplankton pigments chlorophyll-a showed a positive relationship with marker pigment fucoxanthin. Of the four phytoplankton groups studied, the percent dominance was in the order: diatoms > nanoflagellates > cyanobacteria > dinoflagellates. Our study shows that the utilization of halocarbons during microbial oxidation of organic matter could be a significant sink of these compounds although they might be produced in significant quantities by biochemical processes during high productivity periods, as can be seen from our observations in summer monsoon in the Arabian Sea. © 2010 Elsevier Ltd. All rights reserved.

Agency: European Commission | Branch: FP7 | Program: MC-IIFR | Phase: PEOPLE-2007-4-2.IIF | Award Amount: 15.00K | Year: 2012

The Indian Subcontinent occupies <3% of the total land area of the world; however, as much as 22% of the worlds human population lives here, in rough proportion to which the region accounts for ~19% (17 million tonnes of N annually) of the global synthetic N fertilizer consumption. Fossil fuel combustion is the other major source of new N introduced to the environment. The fate of the enormous N loading, which has increased by a factor of 50 over the past 4 decades, is largely unknown. Less than 5% of the anthropogenic N appears to reach the sea by river runoff; the rest presumably accumulates in the terrestrial aquatic systems where an unknown fraction may be removed as N2 or N2O through redox transformations, especially in anaerobic environments of the subsurface aquifers and hyperlimnions of stratified reservoirs and lakes. Given the serious health hazards of high nitrate levels in drinking water and the high greenhouse potential of N2O, both nitrate accumulation in natural waters and conversion of fixed N to N2O are of immense socio-economic significance. The proposed study will, for the first time, investigate N cycle processes in groundwaters and lakes/reservoirs in India. Three man-made reservoirs and one natural lake, and groundwater aquifers of three different types will be seasonally sampled for this purpose. The four major components of the project will be: (a) to study the spatial and temporal variations of various dissolved N species (organic N, nitrate, nitrite, ammonium, N2O and N2) in relation to organic matter loading and ambient dissolved oxygen levels; (b) to determine rates of redox transformations (denitrification and anaerobic ammonium oxidation) and assess their relative importance in N2 production; (c) to identify sources of N and understand mechanisms of its transformations through natural N and O isotope abundance measurements; and (d) to characterize through molecular analyses the microbial community involved in redox transformations.

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