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Abstract: Biological CO2 sequestration using algal reactors is one of the most promising and environmentally benign technologies to sequester CO2. This research study was taken up to alleviate certain limitations associated with the technology such as low CO2 sequestration efficiency and low biomass yields. The study demonstrates an increase in CO2 sequestration efficiency by maneuvering chemically aided biological sequestration of CO2. Chlorella sp. and Spirulina platensis showed 46% and 39% mean fixation efficiency, respectively, at input CO2 concentration of 10%. The effect of acetazolamide, a potent carbonic anhydrase inhibitor, on CO2 sequestration efficiency was studied to demonstrate the role of carbonic anhydrase in calcite deposition. Calcite formed by both species was characterized by scanning electron microscopy coupled electron dispersive spectroscopy and X-ray diffraction. The overall scheme of calcite deposition coupled CO2 fixation with commercially utilizable biomass as a product seems a viable option in the efforts to sequester increasing CO2 emissions. [Copyright &y& Elsevier]

Landfill being the reservoir of organic waste, serves as the most important source in the generation and emission of bioaerosols in the environment, and these bioaerosols have a significant impact on the environment and public health. In India, there are limited studies on the characterization of culturable bacteria and fungi in the bioaerosols originating from landfills. Therefore, the present study aimed to quantify and identify the bioaerosols and study their characteristics at a landfill site in Nagpur, India. The study describes the seasonal variation of PM 2.5 , PM 2.5 -associated bacteria and fungi in the landfill air, their molecular identification, antibiotic resistance, pathogenicity, dispersion and health risk assessment during winter and pre-monsoon seasons at the landfill site and surrounding residential sites in upwind and downwind directions. The study showed PM 2.5 concentration was highest in the winter season (265.56 μg/m3) followed by the pre-monsoon season (173.1 μg/m3) at the landfill site. The culturable bioaerosol level was also significantly higher in winter (11056 CFU/m3) in comparison to pre-monsoon season (2244 CFU/m3) at the landfill site. Upon isolating and characterizing the microorganisms in the bioaerosols, some of the bacterial isolates, like Bacillus, Staphylococcus gallinarum, and Streptomyces speibonae were found to be resistant to chloramphenicol, netillin, nitrofurantoin, streptomycin etc. About 30% of the bacterial isolates were found to show β-hemolytic virulence activity. This indicated the presence of multi-drug resistant and potentially pathogenic bacteria in the bioaerosols over the landfill. The health risk assessment in adults indicated that the workers at the landfill site were at risk of bacterial aerosol in the winter season (hazard quotient i.e., HQ>1). The impact of bioaerosols on children needs to be investigated in the further studies and regular monitoring of bioaerosols is suggested to avoid any morbidity. To the best of our knowledge, this is the first study on the characterization of microorganisms from the bioaerosols over an open landfill site in India. • PM 2.5 and PM 2.5 associated culturable bioaerosols were collected from the Bhandewadi landfill site in Nagpur, India. • The culturable bioaerosol level was significantly higher in winter (11056 CFU/m3) than in pre-monsoon (2336 CFU/m3). • The bacteria isolated from the landfill site were resistant to Chloramphenicol, Netillin, Nitrofurantoin, Streptomycin etc. • The hazard quotient (HQ) by inhalation and dermal contact was calculated for male and females. [ABSTRACT FROM AUTHOR]

Chronic exposure to fluoride has been associated with the development of skeletal fluorosis. Limited reports are available on fluoride induced histone modification. However, the role of histone modification in the pathogenesis of skeletal fluorosis is not investigated. In the present study, we have investigated the role of fluoride induced histone modification on fluorosis development using human osteosarcoma (HOS) cell line. The expression of histone methyltransferases (EHMT1 and EHZ2) and level of global histone trimethylation (H3K9 and H3K27) have been assessed and observed to be increased significantly after fluoride exposure (8 mg/L). EpiTect chromatin immunoprecipitation (CHIP) qPCR Array (Human TGFβ/BMP signaling pathway) was performed to assess the H3K9 trimethylation at promoter regions of pathway-specific genes. H3K9 ChIP PCR array analysis identified hyper H3K9 trimethylation in promoter regions of TGFBR2 and SMAD3. qPCR and STRING analysis was carried out to determine the repressive epigenetic effect of H3K9 trimethylation on expression pattern and functional association of identified genes. Identified genes (TGFBR2 and SMAD3) showed down-regulation which confirms the repressive epigenetic effect of promoter H3K9 hyper trimethylation. Expression of two other vital genes COL1A1 and MMP13 involved in TGFBR2-SMAD signaling pathway was also found to be down-regulated with a decrease in expression of TGFBR2 and SMAD3. STRING analysis revealed functional association and involvement of identified genes TGFBR2, SMAD3, COL1A1 and MMP13 in the collagen and cartilage development/morphogenesis, connective tissue formation, bio-mineral tissue development, endochondral bone formation, bone and skeletal morphogenesis. In conclusion, present investigation is a first attempt to link fluoride induced hyper H3K9 tri-methylation mediated repression of TGFBR2 and SMAD3 with the development of skeletal fluorosis. [ABSTRACT FROM AUTHOR]

Endosulfan, an organochlorine pesticide, is known to induce multiple disorders/abnormalities including neuro-degenerative disorders in many animal species. However, the molecular mechanism of endosulfan induced neuronal alterations is still not well understood. In the present study, the effect of sub-lethal concentration of endosulfan (3 μM) on human neuroblastoma cells (SH-SY5Y) was investigated using genomic and proteomic approaches. Microarray and 2D-PAGE followed by MALDI-TOF-MS analysis revealed differential expression of 831 transcripts and 16 proteins in exposed cells. A gene ontology enrichment analysis revealed that the differentially expressed genes and proteins were involved in variety of cellular events such as neuronal developmental pathway, immune response, cell differentiation, apoptosis, transmission of nerve impulse, axonogenesis, etc. The present study attempted to explore the possible molecular mechanism of endosulfan induced neuronal alterations in SH-SY5Y cells using an integrated genomic and proteomic approach. Based on the gene and protein profile possible mechanisms underlying endosulfan neurotoxicity were predicted. [ABSTRACT FROM AUTHOR]

Recent evidence shows that water distribution system (WDS) is a major risk factor in piped water supply system and the degree of contamination of water in WDS is usually influenced by seasonal variation. Risk assessment studies eliminate the effect of seasonality whenever annualized estimate of concentration of contaminants in water is used to determine the risk to health. In tropical climate where strong seasonal variation prevails, the excess risk during dry and hot season, above the annualized risk can be significant. This study investigates what impact seasonal adjustment may have on health improvement targets for WDS. Water quality data of two Nigerian water supply schemes were used to estimate the impact of WDS on water quality. Seasonal deviation from the annualized impact was quantified as the latent risk in disability-adjusted life years (DALYs). The hazards identified in both WDSs were cadmium and lead, and the estimated 95th-percentile risk of the metals, over the course of dry season was about 31–38%, and 1–3% higher than the estimated yearly average risk, respectively. Wilcoxon signed-rank test showed that the risk distributions during the dry season was significantly higher (p < 0.05) than the yearly average. The median latent risks (5th, 95th-percentiles), for both WDS were 0.014 (7.6 × 10−3, 0.023) and 4.8 × 10−3 (–, 7.6 × 10−3) DALYs/person/year for cadmium and 0.87 × 10−3 (0, 0.1 × 10−3) and 0.16 × 10−3 (0, 0.031 × 10−3) DALYs/person/year, respectively, for lead. These risks are substantially higher than the WHO limit (1 × 10−6 DALYs/person/year). Therefore, to achieve effective health improvement target, mitigation measures should be planned and executed by season. [ABSTRACT FROM AUTHOR]