Hexavalent chromium reduction and plant growth promotion by Staphylococcusarlettae strain Cr11

Cr(VI), a mutagenic and carcinogenic pollutant in industrial effluents, was effectively reduced by an indigenous tannery effluent isolate Staphylococcus arlettae strain Cr11 under aerobic conditions. The isolate could tolerate Cr(VI) up to 2000 and 5000 mg L⁻¹ in liquid and solid media respectively. S. arlettae Cr11 effectively reduced 98% of 100 mg L⁻¹ Cr(VI) in 24 h. Reduction for initial Cr(VI) concentrations of 500 and 1000 mg L⁻¹ was 98% and 75%, respectively in 120 h. The isolate was also positive for siderophore, indole acetic acid, ammonia and catalase production, phosphate solubilization and biofilm formation in the presence and absence of Cr(VI). The isolate showed halotolerance (10% NaCl) and cross tolerance to other toxic heavy metals such as Hg²⁺, Ni²⁺, Cd²⁺ and Pb²⁺. Bacterial inoculation of Triticum aestivum in controlled petri dish and soil environment showed significant increase in percent germination, root and shoot length as well as dry and wet weight in Cr(VI) treated and untreated samples. This is the first report of simultaneous Cr(VI) reduction and plant growth promotion for a S. arlettae strain.     

A perspective review on medicinal plant resources for their antimutagenic potentials

Environmental Science and Pollution Research - Mutagens present in the environment manifest toxic effects and are considered as serious threat for human health and healthcare. Recent reports reveal...     

Flow cytometric analysis of fish leukocytes as a model for toxicity produced by azadirachtin-based bioagrocontaminant

Azadirachtin is one of the most promising natural biopesticide used to overcome the hazardous effects of different organic pesticides and believed to be more environmentally friendly due to the unique nature of biodegradability. In the present study, the impact of no-observed-effect level (NOEL) dose of an azadirachtin-based bioagrocontaminant, Neemsheild, on the blood profile of Indian major carp, Labeo rohita, was examined. The 96-hr LC₅₀ value of Neemsheild was found to be 44.61 ppm. The total erythrocyte count (TEC), hematocrit (Hcrt), and Hb (hemoglobin) values showed a gradual decrease throughout the experimental period, whereas total leukocyte count (TLC) showed an initial increase followed by decline. Flow cytometric analysis subdivided the entire leukocyte population into four separate groups: thrombocytes together with small lymphocytes, monocytes, neutrophils, and basophils. The fluctuation in leukocyte subpopulation indicated an immunotoxicological effect due to azadirachtin. Clustering of different cell types and similarity percentage values were found to differ greatly from control. It was evident from the study that the cell population comprising small lymphocytes and thrombocytes indicated predominant changes as physiological response of fish to different doses of azadirachtin. Thus, flow cytometric analysis of leukocyte populations may be considered as a biomarker to assess fish toxicity.     

Impact of climate change at species level: a case study of teak in India

In this study, we model the long-term effect of climate change on commercially important teak (Tectona grandis) and its productivity in India. This modelling assessment is based on climate projections of the regional climate model of the Hadley Center (HadRM3) and the dynamic vegetation model, IBIS. According to the model projections, 30% of teak grids in India are vulnerable to climate change under both A2 and B2 SRES scenarios because the future climate may not be optimal for teak at these grids. However, the net primary productivity and biomass are expected to increase because of elevated levels of CO₂. Given these directions of likely impacts, it is crucial to further investigate the climate change impacts on teak and incorporate such findings into long-term teak plantation programs. This study also demonstrates the feasibility and limitations of assessing the impact of projected climate change at the species level in the tropics.     

Environmental Modeling and Methods for Estimation of the Global Health Impacts of Air Pollution

Air pollution is increasingly recognized as a significant contributor to global health outcomes. A methodological framework for evaluating the global health-related outcomes of outdoor and indoor (household) air pollution is presented and validated for the year 2005. Ambient concentrations of PM2.5 are estimated with a combination of energy and atmospheric models, with detailed representation of urban and rural spatial exposures. Populations dependent on solid fuels are established with household survey data. Health impacts for outdoor and household air pollution are independently calculated using the fractions of disease that can be attributed to ambient air pollution exposure and solid fuel use. Estimated ambient pollution concentrations indicate that more than 80% of the population exceeds the WHO Air Quality Guidelines in 2005. In addition, 3.26?billion people were found to use solid fuel for cooking in three regions of Sub Saharan Africa, South Asia and Pacific Asia in 2005. Outdoor air pollution results in 2.7?million deaths or 23?million disability adjusted life years (DALYs) while household air pollution from solid fuel use and related indoor smoke results in 2.1?million deaths or 41.6?million DALYs. The higher morbidity from household air pollution can be attributed to children below the age of 5 in Sub Saharan Africa and South Asia. The burden of disease from air pollution is found to be significant, thus indicating the importance of policy interventions.