Biochemistry of TBT-Degrading Marine Pseudomonads Isolated from Indian Coastal Waters

Abstract Tributyltin (TBT) is a very effective biocide and an active ingredient in antifouling paints. Screening along the Indian coast yielded 49 bacterial isolates capable of TBT assimilation. The screening was done based on the ability of bacteria to grow in mineral salt medium (MSM) containing TBT as the sole source of carbon. All the isolates produced exopolysaccharides (biosurfactants) in the medium which aid in emulsification and thus ease bioavailability of TBT. Five isolates were identified as potent TBT degraders (namely, Pseudomonas pseudoalcaligenes, Pseudomonas stutzeri, Pseudomonas mendocina, Pseudomonas putida, and Pseudomonas balearica) based on their biomass production in MSM containing TBT as the sole source of carbon. In addition to evaluating the potential of individual bacterial strains, the study also focused on using a consortium of bacteria to explore their synergistic effect when grown on TBT. Further tests like growth profile, rhamnolipid secretion profile, extracellular protein secretion profile, and detection of siderophores were performed on these isolates when grown in MSM supplemented with 2 mM TBT concentration. Emulsification activity of the crude extracellular polysaccharides against kerosene was evaluated. It can be therefore inferred that TBT degradation by these marine pseudomonads is a twostep process: (a) dispersion of TBT in the aqueous phase and (b) tin-carbon bond cleavage by siderophores affecting debutylation of TBT. The consortium of bacteria may be effective in the treatment of TBT-contaminated waste water in dry docks

Thermal pollution modelling of cooling water discharge into a closed creek system

1415-1421This paper is focused on the behaviour of the heated effluent discharged at an elevated temperature into the Ennore creek by North Chennai Thermal Power Station (NCTPS). Functioning of thermal power plants near tidal creeks and estuaries, due to the feasibility of intake and discharge of water for cooling poses serious environmental concern from heated water discharge due to the flow characteristics of the creek. Discharge of the heated effluent and its dispersion is a function of ebb and flood flow into the Ennore creek as the creek mouth remains closed for most part of the year. This study aims to investigate the dispersion characteristics of the heated effluent in the near-field and far-field under various discharge and dynamic conditions of the creek using calibrated hydrodynamic models and comparison with the field data measured during varying tidal conditions.</span

Mapping of spatial and temporal variation of shoreline in Poompuhar using comprehensive approach

1292-1296Survey of India topographic map, Remote Sensing satellite imageries, NHO-Chart, GSI maps and ground-truthing data collected by Tamil Nadu PWD over the past four decades have been used to extract the shoreline during the various periods. In addition NIOT has marked the High Tide Line (HTL) during the years 2006 and 2013 which gives real time information on the behaviour of the shoreline. Data is processed and analyzed using software ERDAS for image processing and Arc-GIS for geospatial analysis respectively. Rate of shoreline changes are estimated by overlay analysis in GIS environment. The influence of natural and anthropogenic processes along the coast which is found to modify the shoreline configuration has been analyzed.Shoreline has been mapped using Landsat satellite data andTamil Nadu PWD ground truthing data for 1990, 2000 and 2006. It is observed that the shoreline change is more than 30 meters between 1990 and 2006. Studies include linking the natural impacts due to geology of the region and coastal geomorphology influenced by the River Cauvery on the shoreline change.</span

Sidelobe elimination for generalized synthetic discriminant functions by a two-filter correlation and subsequent postprocessing of the intensity distributions

One of the most important problems in optical pattern recognition by correlation is the appearance of sidelobes in the correlation plane, which causes false alarms. We present a method that eliminate sidelobes of up to a given height if certain conditions are satisfied. The method can be applied to any generalized synthetic discriminant function filter and is capable of rejecting lateral peaks that are even higher than the central correlation. Satisfactory results were obtained in both computer simulations and optical implementation

Stachys sieboldii Extract Supplementation Attenuates Memory Deficits by Modulating BDNF-CREB and Its Downstream Molecules, in Animal Models of Memory Impairment

Cholinergic dysfunction, impaired brain-derived neurotrophic factor and cAMP response element binding protein (BDNF-CREB) signaling are one of the major pathological hallmarks of cognitive impairment. Therefore, improving cholinergic neurotransmission, and regulating the BDNF-CREB pathway by downregulating apoptosis genes is one strategy for inhibiting the etiology of dementia. This study evaluates the potential effects of Stachys sieboldii MIQ (SS) extract against cognitive dysfunction and its underlying mechanisms. SS supplementation for 33 days improved scopolamine-induced memory impairment symptoms in Morris water maze test and Y-maze test. SS reduced the acetylcholineesterase activity and significantly increase acetylcholine and cholineacetyltransferase activity in the brain. In the subsequent mechanism study, SS regulated the mRNA expression level of neuronal plasticity molecules such as (nerve growth factor) NGF, BDNF, CREB, and its downstream molecules such as Bcl-2 and Egr-1 by downregulating the neuronal apoptosis targets in both hippocampus and frontal cortex. Additionally, inward currents caused by SS in hippocampal CA1 neurons was partially blocked by the GABA receptor antagonist picrotoxin (50 &mu;M), suggesting that SS acts on synaptic/extrasynaptic GABAA receptors. These findings indicate that SS may function in a way that is similar to nootropic drugs by inhibiting cholinergic abnormalities, and neuronal apoptosis targets and ultimately increasing the expression of BDNF-CREB