Construction of green fluorescent protein based bacterial biosensor for heavy metal remediation

Environmental contamination by heavy metals is a worldwide problem. Therefore, it is necessary to develop sensitive, effective and inexpensive methods, which can efficiently monitor and determine the level of hazardous metals in the environment. Conventional techniques to analyze metals, suffer from the disadvantages of high cost. Alternatively, development of simple system for monitoring heavy metals pollution is therefore needed. The present approach is based on the use of bacteria that are genetically engineered so that a measurable signal is produced when the bacteria are in contact with the bioavailable metal ions. Reporter genes are widely used as genetic tools for quantification and detection of specific cell population, gene expression and constructing whole cell biosensors as specific and sensitive devices for measuring biologically relevant concentrations of pollutants. An attempt has been made to construct the reporter gene enhanced green fluorescent protein and was expressed under the control of cadR gene, responsible for cadmium resistance. Recombinant strain Escherichia coli cadR30 was used, that carried cadR gene in pET30b expression vector and cloned. Clones confirmed by the expression of enhanced green fluorescent protein was detected under ultraviolet illumination and separated on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The construction of green fluorescent protein based Escherichia coli bacterial biosensor was developed based on green fluorescent protein expression under the control cadR gene of Pseudomonas aeruginosa BC15. The constructed bacterial biosensor is useful and applicable in determining the availability of heavy metals in soil and wastewater.     

Heavy metal distribution in sediments of Muthupettai mangroves, south east coast of India

Core sediments from the Muthupettai mangroves on the southeast coast of India were analyzed for soil texture,total nitrogen,organic carbon,phosphorus and heavy metals(Fe,Mn,Cr,Cu,Ni,Pb,Zn and Cd).The distinct seasonal variation in the distribution of metals in the sediments was observed.The minimum concentration was recorded in river mouth and the maximum was in lagoon.High metal concentration in sediment was observed during monsoon and low concentration in summer.The total nu-trient in lagoon and river mouth was recorded in the range of 4.528 to 8.526 mg g-1 for organic carbon,2.213 to 10.5 mg g-1 for nitro-gen and 0.824 to 7.22 mg g-1.     

Narrow-Band Imaging System for the Multi-application Solar Telescope at Udaipur Solar Observatory: Characterization of Lithium Niobate Etalons

The Multi-application Solar Telescope is a 50 cm off-axis Gregorian telescope that has been installed at the lake site of Udaipur Solar Observatory. For quasi-simultaneous photospheric and chromospheric observations, a narrow-band imager has been developed as one of the back-end instruments for this telescope. Narrow-band imaging is achieved using two lithium niobate Fabry–Perot etalons working in tandem as a filter. This filter can be tuned to different wavelengths by changing either voltage, tilt, or temperature of the etalons. To characterize the etalons, a Littrow spectrograph was set up in conjunction with a 15 cm Carl Zeiss Coudé solar telescope. The etalons were calibrated for the solar spectral lines Fe i 6173 Å, and Ca ii 8542 Å. In this work, we discuss the characterization of the Fabry–Perot etalons, specifically, the temperature and voltage tuning of the system for the spectral lines proposed for observations. We present the details of the calibration set-up and various tuning parameters. We also present solar images obtained using the system.     

Spatial Scale Effects of Climate Scenarios on Simulated Cotton Production in the Southeastern U.S.A.

We examine the effect of climate scenarios generated using results from climate models of different spatial resolution on yields simulated by the deterministic cotton model GOSSYM for the southeastern U.S.A. Two related climate change scenarios were used: a coarse-scale scenario produced from results of a general circulation model (GCM) which also provided the boundary conditions to a regional climate model (RCM), from which a fine-scale scenario was constructed. Cotton model simulations were performed for three cases: climate change alone; climate change and elevatedCO₂; climate change, elevated CO₂ and adaptations to climate change. In general, significant differences in state-average projected yield changes between the coarse and fine-scale scenarios are found for these three cases. In the first two cases, different directions of change are found in some sub-regions. With adaptation, yields substantially increase for both climate scenarios, but more so for the coarse-scale scenario (30%domain-average increase). Under irrigation, yield change differences between the two climate scenarios are small in all three cases, and yields are higher under irrigation ( 35% domain-average increase with adaptation case) compared to dryland conditions. For the climate change alone case, differences in summer water-stress levels explain the contrasts in dryland yield patterns between the coarse and fine-scale climate scenarios.     

Characterization of organic matter deposited in the oriental zone from Moknine hypersaline environment, oriental Tunisia

The geochemistry data show that the total organic carbon （TOC） contents are high in the surface sediments in the eastern part of the Moknine＇ s Sebkha. Low decreasing of organic matter （ OM ） with increasing depth indicates the good preservation of OM in modern sediments. ＂Lignite levels＂ inserted in the sand sequence and deposited at the edge and in the intermediate zone are considered as lithologic and organic markers. It is characterized by high TOC and poor hydrogen index （HI） , indicating a higher plant origin and good preservation of OM in thin beds under anoxic condition. In all samples low values of HI are typical for strong terrigenous input in the Sebkha. Gas chromatography （GC） of saturate fraction showed that OM in the border zone is provided from plants but in the central zone OM is a mixture of terrestrial fraction and little fraction from microalgae. The study of free lipids indicated that this environment was influenced by intense bacterial and microbial activities, as evidenced by the abundance of n-alkanes and nC18-nC22.     

Malaysian fisheries policy : Search for new grounds

Past fisheries development policies in Malaysia are assessed and new grounds for managing the Malaysian fisheries are explored. Some incompatibility in the goals for fishery development are discerned, especially those of increasing domestic landings through mechanization and resource conservation. Future management efforts should be based on a fuller understanding of the fishery stock and regional management of fish stocks. Aquaculture is often seen as a plausible alternative in order to augment supplies from the capture fisheries. A comprehensive multidisciplinary approach is needed to transform and commercialize traditional, experience-dependent culture systems into technology-packaged systems based on scientific methods. There is also substantial potential for the development of recreational fisheries.     

Monsoon activity and coupling between low-latitude and high-latitude stratospheric activities

From a Fourier analysis of the monthly mean values of the northern hemispheric geopotential heights at 30 and 50 mb levels, for the period 1972–1979, the transports of momentum and of sensible heat, and the energy conversion terms,C(K _E ,K _Z ) andC(A _Z ,A _E ), have been computed along 30°N and 60°N latitutudes. The variation in these dynamical parameters at 60°N, in relation to monsoon activity in low latitudes and the easterly and westerly phases of the QBO over Gan Island, suggest that a coupling may exist between the high-latitude stratospheric changes and low-latitude monsoon activity and that the low-latitude stratospheric activity modulates high-latitude circulation, confirming the results obtained byHolton andTan (1980) and byLabitzke (1983). The study of the low-latitude stratospheric changes in relation to the high-latitude warmings also indicates a linkage between the low- and high-latitude features     

Dynamics of the stationary eddies in the lower stratospheric circulation in the wavenumber domain and monsoon activity

Meridional transports of momentum and sensible heat have been computed using the Fourier coefficients of the geopotential heights at 50 mb and 30 mb levels for each month during the years 1972 to 1979. Seasonal variations in these transports and in the energy conversionsC (K _E ,K _Z ) andC (A _z ,A _E ) in the contrasting years of monsoon activity have been discussed. The transport and the conversion terms undergo annual variations only with winter maxima and summer minima. Large northward transport of momentum and of sensible heat in the low latitude summer and in the high latitude preceeding winter suggests a linkage between monsoon activity and high latitude stratosphere. Seasonal variations in the energy conversion termsC (K _E ,K _Z ) andC (A _Z ,A _E ) conform with the changes in the system in the years of widely differing monsoon activity both in low and high latitudes. Large conversion of energy fromA _Z toA _E in low latitude summer indicates weakening of the existing meridional temperature gradient, in bad monsoon years.