R. Arthur James

Synthesis and concentration dependent antibacterial activities of CuO nanoflakes

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 Au and Bu 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.

A comparative study on the binding of single and double chain surfactant-cobalt(III) complexes with bovine serum albumin.

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 10(4)-10(5) 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 Förster 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.

Synthesis and Antifungal Studies on CuO Nanostructures

We report, synthesis and antifungal activities of CuO nanoparticles. Particles are prepared through sol-gel method. X-ray diffraction studies show the particles are monoclinic (crystalline) in nature. Scanning electron microscopic measurements are carried out to understand the morphology of the prepared particles. Energy-dispersive X-ray spectroscopic measurements show that the prepared particles containing Cu and O. To identify the local structure of the particles Fourier transform infra red (FTIR) spectroscopic measurements were carried out showing vibrational bands of Cu-O and O-H band. Anti fungal studies were performed on the set of fungal using disk diffusion method and found that the prepared particles are suitable for antifungal activities.

Screening of Chromium-Resistant Bacteria for Plant Growth-Promoting Activities

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 Bergeys 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 their cell walls. Furthermore, Pseudomonas sp. VRK3 was demonstrated to possess mobilization of chromium from the soil that would enhance chromium availability to the plant. Potential use of this Pseudomonas sp. VRK3 as PGPB needs further testing in enhancing the growth and chromium uptake by the plants in pots under nursery conditions.

Marine Drugs Development and Social Implication

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.

Sand Mining, Channel Bar Dynamics and Sediment Textural Properties of the Kaveri River, South India: Implications on Flooding Hazard and Sustainability of the Natural Fluvial System

The Kaveri River, the fourth largest river in India, undergoes the onslaught of urbanization and extensive construction activities within, along and adjoining its channel. In addition to its dwindling natural flow due to the failing monsoonal supply, and constructions of major, medium and minor dams, the extensive mining of sand from its channel bed causes severe stress on its natural fluvial processes. Reduction of carrying capacity of the channel, extensive vertical accretion of sediments within the channel, development of channel-in-channel physiography, and alteration of stream configuration and textural parameters of the stream bed sediments have contributed towards deterioration of the environmental integrity of this important river and exacerbated the flood hazard in the adjoining regions. This paper is an attempt to document the deterioration of natural fluvial dynamics due to the anthropogenic intervention and lack of required data for proper understanding for environmental management and sustenance of the fluvial system. The textural and geomorphic characteristics and the mechanism of mid-channel bar formation and stabilization documented through this study suggest that the whole of the river channel of the Kaveri River behaves like a braided bar/flood plain, which means the prevalence of slow abandonment of the fluvial processes, that could only be observed in the flood plain region of mature and or old stage of a river and/or in the event of shifting of channel course. Occurrence of such characteristics at the upper deltaic region and the observation that the channel area gets converted into mid-channel bars (in terms of textural-geomorphic traits), at a rate of 1.08 km2/year warrant immediate measures for the restoration of natural fluvial processes.

Marine hydrothermal vents as templates for global change scenarios

Subsurface marine hydrothermal vents (HVs) may provide a particular advantage to better understand evolutionary conditions of the early earth and future climate predictions for marine life. Hydrothermal vents (HV) are unique extreme environments that share several similarities with projected global and climate change scenarios in marine systems (e.g., low pH due to high carbon dioxide and sulfite compounds, high temperature and turbidity, high loads of toxic chemicals such as H2S and trace metals). Particularly, shallow hydrothermal vents are easily accessible for short-term and long-term experiments. Research on organisms from shallow HVs may provide insights in the molecular, ecological, and evolutionary adaptations to extreme oceanic environments by comparing them with evolutionary related but less adapted biota. A shallow-water hydrothermal vent system at the northeast Taiwan coast has been intensively studied by several international research teams. These studies revealed astounding highlights at the levels of ecosystem (being fueled by photosynthesis and chemosynthesis), community (striking biodiversity changes due to mass mortality), population (retarded growth characteristics), individual (habitat attractive behavior), and molecular (adaptations to elevated concentrations of heavy metals, low pH, and elevated temperature). The present opinion paper evaluates the potential of shallow hydrothermal vents to be used as a templates for global change scenarios.

Environmental Integrity of the Tamiraparani River Basin, South India

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.