Mercury and organomercurial resistance in bacteria isolated from freshwater fish of wetland fisheries around Calcutta

Mercury-resistant bacteria belonging to the genera Bacillus, Escherichia, Klebsiella, Micrococcus, Pseudomonas, Salmonella, Sarcina, Shigella, Staphylococcus and Streptococcus were isolated from gills and guts of fresh water fish collected from wetland fisheries around Calcutta, India, contaminated with mercury compounds. The total number of bacteria, as well as Hg-resistant bacteria, were always higher in guts than gills. Bottom-dwelling fish contained higher number of bacteria, including Hg-resistant bacteria, than surface and middle water dwelling fish. They belonged either to narrow-spectrum or to broad-spectrum Hg-resistant groups and they also possessed other heavy metal and antibiotic resistant properties. In the presence of toxic levels of HgCl(2), phenylmercuric acetate (PMA) and methylmercuric chloride (MMC), the lag in growth of the bacterial strains gradually increased with increasing concentration of Hg-compounds. Narrow-spectrum Hg-resistant bacterial strains volatilized only HgCl(2) from the liquid medium in the range of 64-89%, whereas the broad-spectrum group exhibited a high level of HgCl(2) (80-94%), PMA (72-84%) and MMC (64-80%) volatilizing capacity with inducible mercuric reductase and organomercurial lyase enzyme activities in their cell-free extracts. Cell-free extracts prepared from narrow-spectrum Hg-resistant bacterial strains induced by HgCl(2) exhibited Hg(+2)-dependent NADPH oxidation, indicating the presence of only mercuric reductase enzyme.     

Future Greenhouse Gas and Local Pollutant Emissions for India: Policy Links and Disjoints

This paper estimates the future greenhousegas (GHG) and local pollutant emissions forIndia under various scenarios. Thereference scenario assumes continuation ofthe current official policies of the Indiangovernment and forecasts of macro-economic,demographic and energy sector indicators.Other scenarios analyzed are the economicgrowth scenarios (high and low), carbonmitigation scenario, sulfur mitigationscenario and frozen (development) scenario.The main insight is that GHG and localpollutant emissions from India, althoughconnected, do not move in synchronizationin future and have a disjoint under variousscenarios. GHG emissions continue to risewhile local pollutant emissions decreaseafter some years. GHG emission mitigationtherefore would have to be pursued for itsown sake in India. National energy securityconcerns also favor this conclusion sincecoal is the abundant national resource whilemost of the natural gas has to be imported.The analysis of contributing factors tothis disjoint indicates that sulfurreduction in petroleum oil products andpenetration of flue gas desulfurisationtechnologies are the two main contributorsfor sulfur dioxide (SO₂) mitigation.The reduction in particulate emissions ismainly due to enforcing electro-staticprecipitator efficiency norms in industrialunits, with cleaner fuels and vehicles alsocontributing substantially. These policytrends are already visible in India.Another insight is that high economicgrowth is better than lower growth tomitigate local pollution as lack ofinvestible resources limits investments incleaner environmental measures. Ouranalysis also validates the environmentalKuznets' curve for India as SO₂emissions peak around per capita GDP ofUS$ 5,300–5,400 (PPP basis) under variouseconomic growth scenarios.     

Effect of noise exposure (85 dB ) on testicular adrenocortical steroidogenic key enzymes, acid and alkaline phosphatase activities of sex organs in mature albino rats

Changes in the activities of △5-3β-hydroysteroid dehydrogenase (HSD) in testis and adrenal gland, 17β-hydroxysteroid dehydrogenase in testis, acid and alkaline phosphatase in testis, prostate and seminal vesicle were observed in noise exposed mature rats at the intensity of 85 dB for 8 h/day for 45 days. The results indicated that noise exposed group showed a significant diminution in the activities of androgenic key enzymes △5-3β and 17β-HSD, acid phosphatase in testis, prostate and seminal vesicle. There was a significant elevation in the activities of adrenal △5-3β-HSD, alkaline phosphatase in testis and other accessory sex organ in noise exposed group. Gonadosomatic, prostatosomatic and seminal vesiculo-somatic indexes were decreased significantly in noise exposed group. Therefore, it is evident that noise exposure at 85dB exerts a deleterious effect on testicular and adrenocortical activities.     

天然有机质模型化合物分子结构对碳纳米管分散性的影响

研究了不同分子结构的天然有机物质（NOM）模型化合物单宁酸（TA）、没食子酸（GA）和十二烷基苯磺酸钠（SDBS）对碳纳米管（CNTs）分散性的影响.通过计算得出,TA的临界胶束浓度（CMC）为1.12mmol/L,SDBS的CMC为0.24mmol/L,GA在所测试的浓度范围内没有形成胶束.比较NOM在CNTs表面的吸附过程和CNTs的分散过程,表明空间位阻和胶束包裹是2个促进CNTs分散的主要机理.借助透射电子显微镜（TEM）和测量悬浮的CNTs的平均流体动力学直径（DLS）结果表明,TA在较少的固相吸附量（S_e ≈ 0.01mmol/g）就能使CNTs分散,归因于其吸附后刚性芳香三维结构的TA能形成的较大空间位阻;同样具有芳香平面结构的GA分子在CNTs表面的吸附需要达到一定的厚度（S_e > 0.2mmol/g）,才能有效地分散CNTs;具有烷基脂肪链的SDBS,需要在形成半胶束或胶束后（S_e > 0.13mmol/g） CNTs才能有效地被分散.芳香族刚性结构和脂肪族柔性结构的模型化合物对CNTs的分散效果和机理存在较大的差别.     

Modelling of the contribution of dissolved inorganic nitrogen (DIN) from litterfall of adjacent mangrove forest to Hooghly–Matla estuary,India

Hooghly–Matla estuarine ecosystem of India is very rich in natural resources and receives large amount of nutrients through litterfall from adjacent mangrove forest. Nitrogen as an important nutrient occurs in various forms and plays a crucial role in the regulation of productivity in this estuarine system. Modelling of nitrogen dynamics from mangrove litterfall and particularly the release of dissolved inorganic nitrogen in this estuarine system is important because of its role in augmenting growth of phytoplankton and other higher plants and all other biological components of grazing food chain.