Hepatoprotective effects of taurine against mercury induced toxicity in rats

An attempt has been made to study the influence of taurine on mercury intoxicated rats. The animals were treated with sublethal dose of mercuric chloride (2 mg/kg body wt.) for 30 days. During the mercury treatment, the level ofAspartate transaminase(AST), Alanine transaminase (ALT) and Alkaline phosphatase(ALP) in serum and lipid peroxidation (LPO) in liver tissue significantly increased whereas Glutathione (GSH), Glutathione peroxidase(GPx), Catalase (CAT) and Superoxide dismutase (SOD) were simultaneously decreased in the liver tissue. Present results indicate that the liver tissue was completely damaged, after mercury treatment. In another group of animals, taurine (5 mg/kg body wt.) was administrated for another 15 days. Taurine administration was observed to improve the liver function in mercury intoxicated animal as indicated by the decline in increased levels of AST, ALT and ALP in serum and LPO content in liver tissue. The decreased level of antioxidant system (GSH, GPx, CATand SOD) has been promoted Results suggested that taurine played a vital role in reducing the mercury toxicity in intoxicated animals.     

<Emphasis Type="Italic">Noctiluca</Emphasis> and copepods grazing on the phytoplankton community in a nutrient-enriched coastal environment along the southwest coast of India

The relative grazing impact of Noctiluca scintillans (hereafter referred only Noctiluca) and copepods (Acrocalanus gracilis, Paracalanus parvus, Acartia danae and Oithona similis) on the phytoplankton community in an upwelling–mudbank environment along the southwest coast India is presented here. This study was carried out during the Pre-Southwest Monsoon (April–May) to the Late Southwest Monsoon (August) period in 2014. During the sampling period, large hydrographical transformation was evident in the study area (off Alappuzha, Southwest coast of India); warmer Pre-Southwest Monsoon water column condition got transformed into cooler and nitrate-rich hypoxic waters during the Southwest Monsoon (June–August) due to intense coastal upwelling. Copepods were present in the study area throughout the sampling period with a noticeable increase in their abundance during the Southwest Monsoon. On the other hand, the first appearance of Noctiluca in the sampling location was during the Early Southwest Monsoon (mid-June) and thereafter their abundance increased towards the Peak Southwest Monsoon. The grazing experiments carried out as per the food removal method showed noticeable differences in the feeding preferences of Noctiluca and copepods, especially on the different size fractions of phytoplankton. Noctiluca showed the highest positive electivity for the phytoplankton micro-fraction (av. 0.49 ± 0.04), followed by nano-fraction (av. 0.17 ± 0.04) and a negative electivity for the pico-fraction (av. ?0.66 ± 0.06). In total ingestion of Noctiluca, micro-fraction contribution (83.7%) was significantly higher compared to the nano- (15.7%) and pico-fractions (0.58%). On the other hand, copepods showed the highest positive electivity for the phytoplankton nano-fraction (av. 0.38 ± 0.04) followed by micro- (av. -0.17 ± 0.05) and pico-fractions (av. ?0.35 ± 0.05). Similarly, in total ingestion of copepods, nano-fraction (69.7%) was the highest followed by micro- (28.9%) and pico-fractions (1.37%). The grazing pressure of Noctiluca on the total phytoplankton was found to be 27.7% of the standing stock and 45.6% of the production, whereas in the case of copepods, it was 9.95% of the standing stock and 16.6% of the production. The study showed that the grazing pressure of Noctiluca on the total phytoplankton as well as larger phytoplankton fraction was 2.8- and 8-folds higher than that of the copepods. This suggests the leading role of Noctiluca as an effective grazer of larger phytoplankton along the southwest west coast of India, especially during the Peak/Late Southwest Monsoon.     

Seasonality of macrobenthic assemblages and the biotic environmental quality of the largest monsoonal estuary along the west coast of India

Environmental Science and Pollution Research - This study deals with the macrobenthic assemblages and the biotic environmental quality of Kochi backwaters (KBW), India. Due to the heavy river...     

Implications of rhizospheric heavy metals and nutrients for the growth of alfalfa in sludge amended soil

Rhizospheric distribution of nutrients and heavy metals in sludge amended soil was investigated using the rhizobag technique to give an indication of the release of metals from wastewater sludge. DTPA-extractable Zn, Cd, Ni and Mn, and available P, K and NH4+-N in the rhizosphere were markedly depleted when soil was amended with sludge. There was no conspicuous depletion or accumulation of DTPA-extractable Cu in the rhizosphere when the soil was amended with sewage sludge but DTPA-extractable Fe accumulated in the rhizosphere when the soil was amended with increasing amounts of sludge. The pH value in the rhizosphere increased with distance from the roots when soil was amended with larger amounts of sludge. The exchangeable fraction of Cu in the rhizosphere was depleted whether or not the soil was treated with sludge. Carbonate, oxide, organic and residual fractions of Cu and Zn were depleted in the rhizosphere at a distance of 0-2 mm from the roots when soil was amended with 50% sludge. Application of sewage sludge had a positive effect on alfalfa growth. With an increase in sludge amounts, the concentrations of Fe, Cu and Zn in alfalfa shoots did not change. Soil amendments with less than 25% sludge did not increase the availability or mobility of heavy metals. The depletion in rhizospheric DTPA-extractable Zn, Cd and Ni indicates that with the sole exception of Cu, release of metals from sludge amended soil was very limited.     

Why do satellite imageries show exceptionally high chlorophyll in the Gulf of Mannar and the Palk Bay during the Norteast Monsoon?

The Gulf of Mannar (GoM) and the Palk Bay (PB) are two least studied marine environments located between India and Sri Lanka. Exceptionally high chlorophyll a concentration in the GoM and the PB during the Northeast Monsoon (November–February) is a consistent feature in satellite imageries, which has been attributed to the intrusion of the Bay of Bengal (BoB) waters. The analyses of the Moderate Resolution Imaging Spectroradiometer (MODIS) and field chlorophyll data collected from 30 locations in the Indian sector of the GoM and the PB in January 2011 showed significant overestimations in the satellite data. This error was much higher in the PB (60–80 %) as compared to the GoM (18–28 %). The multivariate analyses evidenced that the exceptionally high satellite chlorophyll in the PB is contributed largely by turbidity, colored dissolved organic matter (CDOM), and bottom reflectance. The paper cautions that though MODIS is superior in estimating chlorophyll a in optically complex waters, there are still chances of overestimations in regions like the PB.