Plasmid profile and curing analysis of Pseudomonas aeruginosa as metal resistant

The isolate Pseudomonas aeruginosa exhibited resistance to heavy metals such as cadmium, chromium, nickel and lead. Plasmid DNA was isolated from P. aeruginosa and designated as pBC15. The size of the plasmid DNA was approximately 23 kb. Escherichia coli DH5α was transformed with plasmid pBC15 subsequired resistance to nickel and ampicillin. The same size of the plasmid was isolated from E. coli transformant and separated on 0.7 % agarose gel electrophoresis. The restriction analysis of pBC15 showed that the plasmid DNA has single site for Bam HI and Eco RI and three sites for Xho I which were compared with 1 Kb DNA and λ Hind III digest molecular markers. Therefore, the size of the plasmid DNA of pBC15 was confirmed to be 23 kb. Curing was carried out by ethidium bromide, acridine orange, novobiocin, sodium dodechyl sulphate and elevated temperature (40 °C). Transformation and curing results suggest that nickel and ampicillin resistance gene was conferred by plasmid DNA. Cadmium resistant gene was present on chromosomal DNA along with the gene for chromium resistance. Lead resistance gene was shown to be present on the chromosomal DNA rather than the plasmid DNA as the cured and uncured cultures remained similar in lead resistance. Therefore, the ability of P. aeruginosa resistant to nickel and ampicillin is plasmid mediated and transferable to other strains whereas cadmium, chromium and lead could be chromosomal encoded. The heavy metal and antibiotic resistances of P. aeruginosa can be used to exploit for clean up industrial wastewater and bioremediation of heavy metal contaminated soil.     

A numerical technique for simulation of cloud seeding experiments

Two numerical cloud seeding experiments, using historic rainfall for the Deccan plateau region in Maharashtra state, were performed adopting different simulation techniques. The data used consisted of 1-day total rainfall for the 5-year period 1951–55. A double-area cross-over design with area randomisation was adopted. The first experiment, EXP-TR, was based on the simulation technique of Twomey and Robertson which involves about 100 hr of Robotron EC-1040 computer time. The second experiment, EXP-MMM was based on a different simulation technique proposed in the present study. The results of EXP-TR and EXP-MMM have shown close agreement. The numerical simulation technique of EXP-MMM is more promising for the following two reasons: (i) the computational time is reduced by about an order of magnitude without compromising the scientific value of the results, and (ii) a direct estimate of the lower limit of the double ratio value which can be detected at 5% level of significance is defined. The results of the two numerical experiments suggested that, for the Deccan plateau region, 15 and 20% increases in rainfall due to seeding could be detected with 80% or more probability in 5 years.     

Variations of thermodynamical parameters in the atmospheric boundary layer over the Deccan plateau region,India

The thermodynamical structure of the atmospheric boundary layer over the Deccan plateau region has been studied with aerological data for 1980 and 1981.The temperatures in the sub-cloud layer were lower on active monsoon days than dose on weak monsoon days. An opposite trend was noticed in the layer above the 900 mbar level. The moisture content on active monsoon days was higher than that on weak monsoon days. The profile of relative humidity above the 850 mbar level showed large deviations between the active and weak monsoon conditions. On active monsoon days the values of dry static stability were higher than those on weak monsoon days. An opposite trend was noticed in the case of moist static stability. On active monsoon days the magnitudes of thev components of wind were small compared with those of theu components, and the latter showed a gradual decrease with height.     

Quantification of submarine groundwater discharge(SGD) using radon,radium tracers and nutrient inputs in Punnakayal,south coast of India

The present study focused on the estimation of submarine groundwater discharge(SGD)and the effects of nutrient fluxes due to the SGD process.The parameters of SGD such as magnitude,character,and nutrient flux in Punnakayal region of South East coast of India were evaluated using multiple tracers of groundwater inputs in 2019.It was found that the elevated values for the tracers in the study area,displayed a gradational change in the values as move from estuarine part to the offshore.Simultaneous occurrence of fresh and saline SGD is observed on the study sites.Also,indicated that the SGD fluxes ranged from 0.04 to 0.12 m^3 m^-2d^-1 at the estuary and0.03-0.15 m^3 m^-2d^-1at the groundwater site.A substantially increased value for 222 Rn activities is distinguished in the estuary to values over 312 dpm L^-1.Nutrient embellishments were generally greatest at locations with substantial meteoric elements in groundwater;however,the recirculation of saltwater through the geological formation could provide a way of transferring terrestrially-derived nutrients to the coastal zone at many places.     

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.     

GIS-based Evaluation of Water Quality Index of groundwater resources around Tuticorin coastal city,south India

Groundwater is a vital source of water for industrial, domestic and agricultural activities in Tuticorin city due to lack of surface water resources; groundwater quality and its suitability for drinking usage were evaluated. A total of 72 groundwater samples were collected from open wells and boreholes during pre and post-monsoon period. Samples were analyzed for physico-chemical properties, major cation and major anions in the laboratory using the standard methods given by the American Public Health Association. The geographic information system-based spatial distribution map of different major elements has been prepared using ArcGIS 9.2. These maps are classified as desirable, maximum permissible and the values that exceed maximum permissible limit are termed as not permissible prescribed by the WHO (2004). From the Piper plot, which gives the cation chemistry, the concentration of the alkalies (Na⁺ and K⁺) exceeds the alkaline earths (Ca²⁺ and Mg²⁺) and those of strong acids exceeds weak acids. In the case of anions, during the two periods strong acid shows dominance over weak acid and HCO₃ ^? and Cl^? have influences almost equal to Na⁺, which indicate the saltwater intrusion into the freshwater aquifer of the study area. A Canadian Council of Ministers for the Environment Water Quality Index (CCME WQI) map was also generated with the GIS technique to better understand the water portability over space. The categories of water quality evaluated by CCME WQI values of major part of the study area fall under fair category during PRM and good category during the POM period. The CCME WQI is a very useful and an efficient tool to summarize and to report on the monitoring data to the decision makers in order to understand the status of the groundwater quality. Finally, the study concludes that the groundwater quality is impaired by man-made activities, and proper management plan is necessary to protect valuable groundwater resources in Tuticorin city.     

Developing a spectral library of mangrove species of Indian east coast using field spectroscopy

Development of a spectral library is a prerequisite for the higher order classification of satellite data and hyperspectral image analysis to map any ecosystem with rich diversity. In this study, sampling methodology, collection of field and laboratory spectral signatures and post-processing methodologies were investigated for developing an exclusive spectral library of mangrove species using hyperspectral spectroscopic techniques. Canopy level field spectra and leaf level laboratory spectra were collected for 34 species (25 true and 9 associated mangroves) from two different mangrove ecosystems of the Indian east coast. Post-processing steps such as removal of water vapour absorption bands, correction of drifts which occur due to the thermal properties of the instrument during data collection and smoothing of spectra for its further utilisation were applied on collected spectra. The processed spectra were then compiled as spectral library.     

Some Unique Characteristics of Atmospheric Interannual Variability in Rainfall Time Series over India and the United Kingdom

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Geostrophic balance over the Arabian Sea and Bay of Bengal regions

Geostrophic balance over the Arabian Sea and Bay of Bengal regions has been studied using the wind data obtained from the AVRO (HS-748) aircraft during the FGGE-MONEX-79.In the Arabian Sea and the Bay of Bengal regions, the observed wind south of 20°N was found to be sub-geostrophic. In the Arabian Sea region the departure at 1500 m was 75–95% and at 3050 m it was 60–65%. In the Bay of Bengal region the departure was 85–95%. In a few cases north of 20°N the observed winds at 3050 m were found to be super-geostrophic in the regions of enhanced monsoon activity, cyclonic circulation reaching up to 6000 m and in the region of monsoon trough.     

Characteristics of cloud drop spectra in tropical warm clouds

Characteristics of cloud drop spectra were studied using 400 samples obtained from 120 warm cumulus clouds formed during the summer monsoon season.The total concentration of cloud drops (N _T) varied from 384 to 884 cm^–3 and the maximum concentration was observed in the layer below the cloud-top. The width of the drop spectrum was broader in the cloud-base region and in the region below the cloud-top. The spectrum was multimodal at all levels except in the cloud-top region where it was unimodal. The concentration of drops with diameter greater than 50 m (N _L) varied from 0.0 to 0.674 cm^–3.N _L was larger in the cloud-base region.N _L decreased with height up to the middle level and thereafter showed an increase. In the cloud-top region no large drops were present. The computed values of the liquid water varied between 0.132 and 0.536 g m^–3 and the mean volume diameter (MVD) varied between 8.1 and 12.0 m. The LWC and MVD showed a decrease with height except in the middle region of the cloud where the values were higher than the adjacent levels. The dispersion of the cloud drops was lower (0.65) in the cloud-top region and higher (1.01) in the cloud-base region.The observed cloud microphysical characteristics were attributed to vertical mixing in clouds induced by the cloud-top gravity oscillations (buoyancy oscillations) generated by the intensification of turbulent eddies due to the buoyant production of energy by the microscale-fractional-condensation (MFC) in turbulent eddies.