20 results on '"R. Arthur James"'
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2. Fingerprints of Climate Change from the Indian Himalayan Environment: Need to Inculcate in Environment Education for Schools and Colleges
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Kanchan Puri, N. Manoharan, R. Arthur James, A. Senthil Vel, and Ritesh Joshi
- Abstract
Himalayas are the youngest mountain range in the world that are experiencing the implications of climate change occurring at the local and regional levels. This does not only affect the ecologically diverse natural landscapes in the Himalayan region but also disrupts the natural habitats and distribution of species. The synthesis of the available literature indicates that abrupt changes in climate, especially at higher elevations are affecting the natural distribution of plant and animal taxa. The unpredictable movement of wildlife beyond their natural ranges underpin disturbances under micro climatic conditions and alteration of environmental niches. Though upslope movement of quite a few species has been observed, the extent to which these can be attributed to climate change is not clearly known. Considering the fingerprints of climate change in the Indian Himalaya, which has been considered as an ecological fragile landscape, there is a need to revisit and restructure our priorities for wildlife conservation. Moreover, monitoring species’ responses over time and documenting indigenous knowledge of local communities would strengthen our actions in addressing the impacts of climate change. Furthermore, by adding climate change education in the school system, considering it to be mandatory, can be remedied only by providing appropriate knowledge and through a structured training programme on climate change mitigation and adaptation process.
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- 2022
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3. Palaeoenvironment and provenance signatures inferred from quartz grain surface features: A case study from Huatabampo and Altata beaches, Gulf of California, Mexico
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R. Arthur James, Jayagopal Madhavaraju, S. M. Hussain, and John S. Armstrong-Altrin
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Provenance ,Geochemistry ,Geology ,engineering.material ,Diagenesis ,Sedimentary depositional environment ,Source rock ,engineering ,Aeolian processes ,Halite ,Quartz ,Conchoidal fracture ,Earth-Surface Processes - Abstract
Microtextures on quartz grains from the Huatabampo (HB) and Altata (AA) beaches, Gulf of California, were analyzed by a scanning electron microscopy (SEM) to infer the depositional history and provenance. In total, 41 microtextures were identified and grouped as mechanical, mechanical/chemical, and chemical mode of origins. Among them, twenty-three microtextures represent mechanical, eight represent mechanical/chemical, and ten represent chemical origin. The microtextures of chemical origin were further classified as dissolutional and precipitational origins. Oriented etch pits, solution pits, solution crevasses, and scaling are classified as of dissolutional origin. Silica globules, silica flower, silica pellicles, crystalline overgrowth, trapped diatoms, and halite crystals are grouped as chemical precipitational origin. The V-shaped marks, straight and curved scratches revealed the combination of fluvial and high energy subaqueous beach environments. The low frequencies of upturned plates, abrasion fatigue, meandering ridges, crescentic percussion marks, bulbous edges and elongated depressions suggest the low abundance of sediments derived by aeolian transport. The microtextures of chemical origin in few grains indicated the diagenetic processes in a silica saturated intertidal zone. The quartz grains from HB and AA beaches reveal varying sizes of conchoidal fractures indicate that they were derived mainly from crystalline source rocks. The association of straight and arcuate steps along with conchoidal fractures further support that the studied quartz grains were liberated from crystalline rocks. The dominance of angular to sub-angular grains indicates short transport and rapid deposition. In addition, straight and arcuate steps are delicate features which might have been destroyed during long transportation. Thus, the presence of straight and arcuate steps features together with angular to sub-angular grains support a nearby source.
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- 2021
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4. Preface
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Mu. Ramkumar, R. Arthur James, David Menie, and K. Kumaraswamy
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- 2019
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5. Biological and protein-binding studies of newly synthesized polymer-cobalt(III) complexes
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S. Vignesh, Ilayaperumal Pradeep, Renganathan Arun, Kumpati Premkumar, G. Vignesh, R. Arthur James, and Sankaralingam Arunachalam
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Quenching (fluorescence) ,biology ,Chemistry ,Biophysics ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,Plasma protein binding ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Human serum albumin ,01 natural sciences ,0104 chemical sciences ,Bipyridine ,chemistry.chemical_compound ,Chemistry (miscellaneous) ,Polymer chemistry ,biology.protein ,medicine ,Bovine serum albumin ,0210 nano-technology ,Mode of action ,Cytotoxicity ,Cobalt ,medicine.drug - Abstract
The polymer-cobalt(III) complexes, [Co(bpy)(dien)BPEI]Cl3 · 4H2O (bpy = 2,2'-bipyridine, dien = diethylentriamine, BPEI = branched polyethyleneimine) were synthesized and characterized. The interaction of these complexes with human serum albumin (HSA) and bovine serum albumin (BSA) was investigated under physiological conditions using various physico-chemical techniques. The results reveal that the fluorescence quenching of serum albumins by polymer-cobalt(III) complexes took place through static quenching. The binding of these complexes changed the molecular conformation of the protein considerably. The polymer-cobalt(III) complex with x = 0.365 shows antimicrobial activity against several human pathogens. This complex also induces cytotoxicity against MCF-7 through apoptotic induction. However, further studies are needed to decipher the molecular mode of action of polymer-cobalt(III) complex and for its possible utilization in anticancer therapy.
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- 2015
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6. Studies on the synthesis, characterization, human serum albumin binding and biological activity of single chain surfactant-cobalt(III) complexes
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R. Arthur James, G. Vignesh, Renganathan Arun, S. Vignesh, Kumpati Premkumar, K. Sugumar, and Sankaralingam Arunachalam
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Circular dichroism ,Chemistry ,Stereochemistry ,Biophysics ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Human serum albumin ,01 natural sciences ,Fluorescence ,Binding constant ,Fluorescence spectroscopy ,0104 chemical sciences ,Crystallography ,Pulmonary surfactant ,Chemistry (miscellaneous) ,medicine ,Steady state (chemistry) ,0210 nano-technology ,Cobalt ,medicine.drug - Abstract
The interaction of surfactant-cobalt(III) complexes [Co(bpy)(dien)TA](ClO4)3 · 3H2O (1) and [Co(dien)(phen)TA](ClO4)3 · 4H2O (2), where bpy = 2,2'-bipyridine, dien = diethylenetriamine, phen = 1,10-phenanthroline and TA = tetradecylamine with human serum albumin (HSA) under physiological conditions was analyzed using steady state, synchronous, 3D fluorescence, UV/visabsorption and circular dichroism spectroscopic techniques. The results show that these complexes cause the fluorescence quenching of HSA through a static mechanism. The binding constant (Kb ) and number of binding-sites (n) were obtained at different temperatures. The corresponding thermodynamic parameters (∆G°, ∆H° and ∆S°) and Ea were also obtained. According to Forster's non-radiation energy transfer theory, the binding distance (r) between the complexes and HSA were calculated. The results of synchronous and 3D fluorescence spectroscopy indicate that the binding process has changed considerably the polarity around the fluorophores, along with changes in the conformation of the protein. The antimicrobial and anticancer activities of the complexes were tested and the results show that the complexes have good activities against pathogenic microorganisms and cancer cells.
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- 2015
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7. Irrigation water quality assessment—an example from the Tamiraparani river, Southern India
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Hans-Uwe Dahms, A. Rajendran, P. Kumarasamy, R. Arthur James, and Hyoung-Joo Jeon
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Hydrology ,Irrigation ,geography ,geography.geographical_feature_category ,Land use ,Weathering ,Estuary ,Dilution ,Salinity ,Streamflow ,General Earth and Planetary Sciences ,Environmental science ,Water quality ,General Environmental Science - Abstract
Irrigation water plays an important role for crop cultivation. Irrigation waters from rivers depend on river flow, lithology, land use patterns, and other anthropogenic activities. We provide here a new assortment for the evaluation of river water quality for irrigation purposes using the Tamiraparani river in India as an example. Physicochemical parameters with sodium absorption ratios (SAR—0.14 to 9.23 meq L−1), sodium percentage (Na%—10.15 to 85.38 meq L−1), residual sodium carbonate (RSC—0.32 to 5.64 meq L−1), potential salinity (PS—0.5 to 7.1 meq L−1), and permeability index (PI—12.5 to 89.7 meq L−1) attest excellent water quality for irrigation except for a few locations in the estuarine region. In addition were the results plotted against USSL (C1S1 to C2S2 class) and Wilcox diagrams confirming >90 % covers under an “Excellent to good” category whereas
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- 2013
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8. Screening of Chromium-Resistant Bacteria for Plant Growth-Promoting Activities
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V. Balasubramanian, R. Arthur James, V. Rajesh Kannan, and B. Hemambika
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Siderophore ,Strain (chemistry) ,biology ,Health, Toxicology and Mutagenesis ,Pseudomonas ,Tryptophan ,Soil Science ,chemistry.chemical_element ,Phosphate ,biology.organism_classification ,Pollution ,Microbiology ,chemistry.chemical_compound ,Chromium ,chemistry ,Environmental Chemistry ,Bacteria ,Waste disposal - Abstract
Chromium-resistant plant growth-promoting bacteria (PGPB) were isolated from the electroplating industry waste disposal site soils at Coimbatore, India, using LB medium. The strain tolerated chromium concentrations up to 500 mg Cr6+L−1 on LB medium. The strain was identified as Pseudomonas sp. VRK3 based on its morphological, physiological, and biochemical characteristics following Bergey's manual of determinative bacteriology. Evaluation of plant growth-promoting parameters revealed the intrinsic ability of the strain for the production of indole-3-acetic acid (IAA), siderophore, and solubilization of insoluble phosphate. Pseudomonas sp. VRK3 utilized tryptophan as a precursor for the growth and production of IAA (105.77 μg mL−1) and also exhibited the production of siderophore. The strain utilized tricalcium phosphate as the sole source of phosphate exhibiting a high rate of phosphate solubilization (0.49 μg mL−1). Pseudomonas sp. VRK3 showed a significant extent of chromium uptake and accumulation in t...
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- 2013
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9. A comparative study on the binding of single and double chain surfactant–cobalt(III) complexes with bovine serum albumin
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R. Arthur James, K. Sugumar, Sankaralingam Arunachalam, S. Vignesh, and G. Vignesh
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Circular dichroism ,Stereochemistry ,chemistry.chemical_element ,Microbial Sensitivity Tests ,Analytical Chemistry ,Surface-Active Agents ,Anti-Infective Agents ,Coordination Complexes ,Animals ,Binding site ,Bovine serum albumin ,Instrumentation ,Micelles ,Spectroscopy ,Binding Sites ,Bacteria ,biology ,Circular Dichroism ,Fungi ,Tryptophan ,Serum Albumin, Bovine ,Cobalt ,Fluorescence ,Binding constant ,Atomic and Molecular Physics, and Optics ,Crystallography ,Spectrometry, Fluorescence ,Energy Transfer ,chemistry ,biology.protein ,Thermodynamics ,Tyrosine ,Cattle ,Spectrophotometry, Ultraviolet ,Steady state (chemistry) ,Absorption (chemistry) ,Protein Binding - Abstract
The comparative binding effect of single and double aliphatic chain containing surfactant–cobalt(III) complexes cis-[Co(bpy)2(DA)2](ClO4)3⋅2H2O (1), cis-[Co(bpy)2(DA)Cl](ClO4)2⋅2H2O (2), cis-[Co(phen)2(CA)2](ClO4)3⋅2H2O (3), and cis-[Co(phen)2(CA)Cl](ClO4)2⋅2H2O (4) with bovine serum albumin (BSA) under physiological condition was analyzed by steady state, time resolved fluorescence, synchronous, three-dimensional fluorescence, UV–Visible absorption and circular dichroism spectroscopic techniques. The results show that these complexes cause the fluorescence quenching of BSA through a static mechanism. The binding constants (Kb) and the number of binding sites were calculated and binding constant values are found in the range of 104–105 M−1. The results indicate that compared to single chain complex, double chain surfactant–cobalt(III) complex interacts strongly with BSA. Also the sign of thermodynamic parameters (ΔG°, ΔH°, and ΔS°) indicate that all the complexes interact with BSA through hydrophobic force. The binding distance (r) between complexes and BSA was calculated using Forster non-radiation energy transfer theory and found to be less than 7 nm. The results of synchronous, three dimensional fluorescence and circular dichroism spectroscopic methods indicate that the double chain surfactant–cobalt(III) complexes changed the conformation of the protein considerably than the respective single chain surfactant–cobalt(III) complexes. Antimicrobial studies of the complexes showed good activities against pathogenic microorganisms.
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- 2013
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10. Multivariate water quality assessment from the Tamiraparani river basin, Southern India
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R. Arthur James, Chan-Woo Byeon, Hans-Uwe Dahms, Ramachandran Ramesh, and P. Kumarasamy
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Hydrology ,Global and Planetary Change ,geography ,Multivariate statistics ,geography.geographical_feature_category ,Perennial stream ,Dissolved silica ,Drainage basin ,Soil Science ,Ternary plot ,Geology ,Weathering ,Pollution ,Principal component analysis ,Environmental Chemistry ,Water quality ,Earth-Surface Processes ,Water Science and Technology - Abstract
The hydrochemistry of a perennial river has been investigated with multivariate cluster analysis (CA) and principal component analysis/factor analysis (PCA/FA). The aim was to investigate parameters responsible for spatial and temporal variations of river water quality. Water quality was monitored along the river basin at 20 different sites over a period of 1 year from July, 2008 to June, 2009. Multivariate statistics revealed that Ca2+, Mg2+, Na+, K+, HCO3 −, Cl−, H4SiO4, SO4 2−, NO2 −, and PO4 3− were influenced by seasonal and spatial variations and that water quality was in the first place determined more by natural weathering processes than by anthropogenic activities. We could prove by (a) Box and Whisker plot, (b) matrix scatter score mean plot, (c) ternary plot, and (d) Gibbs plot that the chemistry of river water is controlled by lithogenic weathering processes. The higher concentration of dissolved silica during summer and the pre-monsoon season is explained by natural and tropical climatic conditions of the environment.
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- 2013
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11. Assessment of Pollution Indicators and Antibiotic Resistant Pattern on Contaminated Canned Juice
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S. Vignesh, Osman Babiker Ali Elibaid, B. Meera, A. Philip Arokiadoss, K. Muthukumar, M. Santhosh Gokul, and R. Arthur James
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Antibiotic resistant strains, Canned food, Indicator bacteria, Food contamination - Abstract
The contaminated canned food sample (Mango juice – acidic nature) was collected from the Perambalur general market during January 2016 for microbiological analysis. The five different bacterial populations were isolated and enumerated from the contaminated mango juice canned food by pure culture technique. In which, fifty (50) bacterial strains were isolated and were challenged against ten different standard antibiotics on Mueller Hinton agar (MHA) by disc diffusion method for antibiotic resistance analysis. The mean level of TVC, TC, TS, FC and FS levels in contaminated canned juice sample were 154.0 x 104, 4.3 x 102, 1.3 x 102, 1.1 x 102, 0.4 x 102 and 2.75, respectively. All the fifty bacterial strains shown a resistant activity to ampicillin and penicillin antibiotic which indicate that these two antibiotic have got no effective and they are very weak to resist against those bacterial strains. In this study, more than 30% of isolates were resistant to single antibiotics whereas double and 3 antibiotic resistances were recorded in contaminated food isolates such as 18.3% and 16.6%, respectively. This sample showed a higher percentage (98.4%) of resistant strains which indicating that most of the strains were resistant to one or more of the tested antibiotics. This bacterial counts and antibiotic resistant strains indicated that the contaminated food samples contain toxic pathogens which may cause serious infection to consumers.
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- 2017
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12. ANTIFUNGAL STUDIES ON BIOCOMPATIBLE POLYMER ENCAPSULATED SILVER NANOPARTICLES
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Balasubramanian Karthikeyan, B. M. Murari, K. Vishwanathan, S. Vignesh, R. Arthur James, R. Anitha, and T. Pandiyarajan
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chemistry.chemical_classification ,Materials science ,Absorption spectroscopy ,Nanoparticle ,Bioengineering ,Nanotechnology ,Polymer ,Condensed Matter Physics ,Silver nanoparticle ,Computer Science Applications ,chemistry ,Polyol ,Chemical engineering ,General Materials Science ,Electrical and Electronic Engineering ,Absorption (chemistry) ,Fourier transform infrared spectroscopy ,Surface plasmon resonance ,Biotechnology - Abstract
Silver nanoparticles are known to have inhibitory antimicrobial properties. In this letter, we report the synthesis of silver nanoparticles by using biocompatible, water soluble polymer through polyol method. Optical absorption spectrum of the prepared particles shows an absorption peak around 433 nm which is because of Surface Plasmon Resonance (SPR) of silver nanoparticles. Fourier transform infrared (FTIR) studies were done to identify the interaction of the nanoparticle and polymer. Transmission Electron Microscopic (TEM) studies confirm that the prepared particles are ~ 100 nm in size. Antifungal activity was studied through standard disk diffusion method. Studies show the prepared particles are potential candidates for the antifungal activity.
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- 2011
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13. Anthropogenic nexus on organochlorine pesticide pollution: a case study with Tamiraparani river basin, South India
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S. Vignesh, R. Arthur James, S. Govindaraj, R. Babu Rajendran, and P. Kumarasamy
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Pollution ,Heptachlor ,media_common.quotation_subject ,Drainage basin ,India ,Management, Monitoring, Policy and Law ,Dieldrin ,chemistry.chemical_compound ,Rivers ,Hydrocarbons, Chlorinated ,Humans ,Aldrin ,Pesticides ,Nonpoint source pollution ,General Environmental Science ,media_common ,geography ,geography.geographical_feature_category ,Sediment ,General Medicine ,chemistry ,Environmental chemistry ,Geographic Information Systems ,Environmental science ,Surface water ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
The levels of 17 organochlorine pesticides residues (OCPs) in surface water and sediments from Tamiraparani river basin, South India were investigated to evaluate their potential pollution and risk impacts. A total of 96 surface water and sediment samples at 12 sampling stations were collected along the river in four seasons during 2008-2009. The ΣOCP concentrations in surface water and sediments were in the range of 0.1 to 79.9 ng l(-1) and 0.12 to 3,938.7 ng g(-1) dry weight (dw), respectively. Among the OCPs, the levels of dichlorodiphenyltrichloroethanes (DDTs), aldrin, dieldrin, cis-chlordane, trans-chlordane, and mirex were dominant in the sediments. The dominant OCPs in water samples are heptachlor, o,p'-DDE, dieldrin, o,p'-DDD, and mirex, which show different source of contamination pattern among sampling seasons. The distribution pattern of DDTs, hexachlorocyclohexane, and other OCPs in the present study shows heterogenic nature of nonpoint source of pollution. Notable contamination of water and sediment sample that was observed in upstream (S2) 58 ng l(-1) and downstream (S11) 1,693 ng g(-1) dw explains agricultural and municipal outfalls, whereas frequent damming effect reduces the concentration level in the midstream. The overall spatial-temporal distribution pattern of ΣOCP residues are illustrated by GIS package.
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- 2011
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14. Marine Drugs: Implication and Future Studies
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R. Arthur James, S. Vignesh, and A. Raja
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Pharmacology ,Future studies ,Natural product ,business.industry ,Biology ,Antimicrobial ,Biotechnology ,Resistant bacteria ,chemistry.chemical_compound ,Drug development ,chemistry ,Secondary metabolism ,business - Abstract
Natural product compounds are the source of numerous therapeutic agents. Recent progress to discover drugs from natural product sources has resulted in compounds that are being developed to treat cancer, resistant bacteria and viruses and immunosuppressive disorders. Many of these compounds were discovered by applying recent advances in understanding the genetics of secondary metabolism in microorganisms, exploring the marine environment and applying new screening technologies. Microbes have made a phenomenal/unique contribution to the health and well-being of people throughout the world. In addition to producing many primary metabolites, such as amino acids, vitamins and nucleotides, they are capable of making secondary metabolites, which constitute half of the pharmaceuticals on the market today (and provide agriculture with many essential products). A growing number of marine microorganisms are the sources of novel and potentially life-saving bioactive secondary metabolites. Here, we have discussed some of these novel antibacterial, antiviral, anticancer compounds isolated from marine-derived microbes and their possible roles in disease eradication and commercial exploitation of these compounds for possible drug development using many approaches.
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- 2010
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15. Biological and protein-binding studies of newly synthesized polymer-cobalt(III) complexes
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G, Vignesh, I, Pradeep, S, Arunachalam, S, Vignesh, R, Arthur James, R, Arun, and K, Premkumar
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Antifungal Agents ,Binding Sites ,Bacteria ,Dose-Response Relationship, Drug ,Molecular Structure ,Polymers ,Fungi ,Apoptosis ,Cobalt ,Microbial Sensitivity Tests ,Anti-Bacterial Agents ,Structure-Activity Relationship ,MCF-7 Cells ,Organometallic Compounds ,Animals ,Humans ,Cattle ,Drug Screening Assays, Antitumor ,Serum Albumin ,Cell Proliferation - Abstract
The polymer-cobalt(III) complexes, [Co(bpy)(dien)BPEI]Cl3 · 4H2O (bpy = 2,2'-bipyridine, dien = diethylentriamine, BPEI = branched polyethyleneimine) were synthesized and characterized. The interaction of these complexes with human serum albumin (HSA) and bovine serum albumin (BSA) was investigated under physiological conditions using various physico-chemical techniques. The results reveal that the fluorescence quenching of serum albumins by polymer-cobalt(III) complexes took place through static quenching. The binding of these complexes changed the molecular conformation of the protein considerably. The polymer-cobalt(III) complex with x = 0.365 shows antimicrobial activity against several human pathogens. This complex also induces cytotoxicity against MCF-7 through apoptotic induction. However, further studies are needed to decipher the molecular mode of action of polymer-cobalt(III) complex and for its possible utilization in anticancer therapy.
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- 2015
16. Studies on the synthesis, characterization, human serum albumin binding and biological activity of single chain surfactant-cobalt(III) complexes
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G, Vignesh, K, Sugumar, S, Arunachalam, S, Vignesh, R, Arthur James, R, Arun, and K, Premkumar
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Jurkat Cells ,Structure-Activity Relationship ,Surface-Active Agents ,Binding Sites ,Cell Death ,Dose-Response Relationship, Drug ,Molecular Structure ,Organometallic Compounds ,Humans ,Thermodynamics ,Cobalt ,Serum Albumin - Abstract
The interaction of surfactant-cobalt(III) complexes [Co(bpy)(dien)TA](ClO4)3 · 3H2O (1) and [Co(dien)(phen)TA](ClO4)3 · 4H2O (2), where bpy = 2,2'-bipyridine, dien = diethylenetriamine, phen = 1,10-phenanthroline and TA = tetradecylamine with human serum albumin (HSA) under physiological conditions was analyzed using steady state, synchronous, 3D fluorescence, UV/visabsorption and circular dichroism spectroscopic techniques. The results show that these complexes cause the fluorescence quenching of HSA through a static mechanism. The binding constant (Kb ) and number of binding-sites (n) were obtained at different temperatures. The corresponding thermodynamic parameters (∆G°, ∆H° and ∆S°) and Ea were also obtained. According to Förster's non-radiation energy transfer theory, the binding distance (r) between the complexes and HSA were calculated. The results of synchronous and 3D fluorescence spectroscopy indicate that the binding process has changed considerably the polarity around the fluorophores, along with changes in the conformation of the protein. The antimicrobial and anticancer activities of the complexes were tested and the results show that the complexes have good activities against pathogenic microorganisms and cancer cells.
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- 2015
17. Environmental Integrity of the Tamiraparani River Basin, South India
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R. Purvaja, R. Arthur James, and Ramachandran Ramesh
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Hydrology ,geography ,geography.geographical_feature_category ,Nutrient ,Perennial stream ,Aquatic ecosystem ,Drainage basin ,Biogeochemistry ,Weathering ,Biota ,Water quality ,Environmental planning - Abstract
Monitoring the surface run-off and physicochemical parameters of a river on a regular basis provides valuable information on the eco-hydrologic conditions of the river basin. The resultant data provide valuable insights into spatial and temporal variation on water quality, considered as a measure of the health of a river. The physicochemical characteristics of any aquatic ecosystem and the nature and distribution of its biota are directly related to and influenced by each other and controlled by a multiplicity of natural regulatory mechanisms. The River Tamiraparani, a perennial river in southern India was studied for comprehensive environmental issues. The major ion chemistry and nutrients of the studied samples show seasonal and spatial variations, under the predominant influence of geogenic (natural weathering) and to certain extent, lesser influence of anthropogenic sources. Application of various geochemical indices (SAR, RSC, PI, PS and Na %) and plots revealed that, a majority of the samples (90 %) are within the permissible limits of the domestic and agricultural usages. The occurrences of organochlorine compounds in the studied samples suggest influx from agricultural activities.
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- 2015
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18. [Untitled]
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H. D. Holland, Al. Ramanathan, S. B. Jacobsen, Ramachandran Ramesh, R. Arthur James, and V. Subramanian
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geography ,geography.geographical_feature_category ,Mineralogy ,Sediment ,Estuary ,Weathering ,Aquatic Science ,Thermal ionization mass spectrometry ,Geochemical cycle ,Silicate ,Salinity ,chemistry.chemical_compound ,chemistry ,Environmental chemistry ,Environmental science ,Bay - Abstract
Bed sediment samples collected from the Hoogly, Godavari, Krishna and Cauvery estuaries on the east coast of India were analyzed for rare earth elements (REEs), mainly lanthanides (La‐Lu), Y, a number of metals (V, Cr, Co, Ni, Zn, Ag, Cd and Pb), using Thermal Ionization Mass Spectrometry. Continental weathering plays an important role in the distribution of REEs and metals. However, metals showed wide variation in concentration among estuaries, mainly due to varying salinity, which controls complex estuarine processes, and partly to anthropogenic inputs. Factor analysis of elemental data identified two major groups of elements: (i) LREEs, HREEs, Cd, Pb and Ag, revealing an association with detritals brought in by the rivers; and (ii) V, Cr , Co, Ni and Zn, indicating complex estuarine processes and human input. LREEs are more enriched than HREEs (LREE/HREE ratio varied between 12 and 40) reflecting silicate weathering of crustal materials, and a resultant increase in LREEs in detritals. We conclude that the estuarine system constitutes 70% of LREEs and 30% of HREE flux to the Bay of Bengal.
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- 1999
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19. Synthesis and concentration dependent antibacterial activities of CuO nanoflakes
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R. Arthur James, S. Vignesh, T. Pandiyarajan, Balasubramanian Karthikeyan, and R. Udayabhaskar
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Materials science ,Scanning electron microscope ,Bioengineering ,Bacillus subtilis ,Microbial Sensitivity Tests ,medicine.disease_cause ,Biomaterials ,Shigella flexneri ,X-Ray Diffraction ,Staphylococcus epidermidis ,Spectroscopy, Fourier Transform Infrared ,medicine ,Fourier transform infrared spectroscopy ,Escherichia coli ,biology ,Bacteria ,Spectrometry, X-Ray Emission ,biology.organism_classification ,Anti-Bacterial Agents ,Crystallography ,Mechanics of Materials ,X-ray crystallography ,bacteria ,Nanoparticles ,Copper ,Monoclinic crystal system - Abstract
We report, synthesis and antibacterial activities of CuO nanoflakes. CuO nanoparticles are prepared at room temperature through sol–gel method. X-ray diffraction studies show the particles are monoclinic (crystalline) in nature. Scanning electron microscopy (SEM) images clearly show that the prepared particles are flake like in structure. Fourier transform infrared (FTIR) spectra exhibits three different bands that correspond to the A u and B u modes. Antibacterial studies were performed on Shigella flexneri , Staphylococcus aureus , Staphylococcus epidermidis , Salmonella typhimurium , Bacillus subtilis , Escherichia coli , Vibrio cholera , Pseudomonas aeruginosa and Aeromonas liquefaciens bacterial strains. Among these bacterial strains, S. flexneri and B. subtilis are most sensitive to copper oxide nanoparticles than the positive control ( Penicillin G ) and S . typhimurium strain shows the less sensitive. Results show that sensitivity is highly dependent on the concentrations of CuO nanoflakes.
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- 2012
20. Marine Drugs Development and Social Implication
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Krishnan Muthukumar, R. Arthur James, and S. Vignesh
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Biopharmaceutical ,Resource (biology) ,Ecology ,Natural resource economics ,Drug discovery ,Bioproducts ,Chemical diversity ,Potential market ,Biology ,Social implication ,Global biodiversity - Abstract
Marine sources have attracted much attention as potential sources for natural products over recent years. The future of the biopharmaceutical holds great promise due to the many compounds that have and will be isolated from marine sources. Marine organisms have long been recognized as a source of novel metabolites with applications in human disease therapy. The marine environment is a rich source of both biological and chemical diversity, where it has been reported that oceans contain nearly 300,000 described species, representing only a small percentage of the total number of species that have to be discovered. The ocean represents a rich resource for ever more novel compounds with great potential as pharmaceutical, nutritional supplements, cosmetics, agrichemicals and enzymes, where each of these marine bioproducts has a strong potential market value. The reasons for the strong showing of drug discovery from natural products can be attributed to the diverse structures, intricate carbon skeletons, and the ease that human bodies will accept these molecules with minimal manipulation. With new pressures from the public and governments around the world to develop products to combat diseases and infections commonly encountered, new chemical entities need to be found and developed.
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- 2012
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