Predicting the combustion behaviour of compression ignition engine fuelled with biodiesel from Stoechospermum marginatum,a macro algae

Environmental Science and Pollution Research - Biodiesel is one among the recent developments in the field of renewable energy research. To enhance the combustion characteristics of compression...     

Cytochrome P450 BM3 of Bacillus megaterium—A possible endosulfan biotransforming gene

Computing chemistry was applied to understand biotransforrnation mechanism of an organochlorine pesticide, endosulfan. The stereo specific metabolic activity of human CYP-2B6 （cytochrome P450） on endosulfan has been well demonstrated. Sequence and structural similarity search revealed that the bacterium Bacillus megaterium encodes CYP-BM3, which is similar to CYP-2B6. The functional similarity was studied at organism level by batch-scale studies and it was proved that B. megaterium could metabolize endosulfan to endosulfan sulfate, as CYP-2B6 does in human system. The gene expression analyses also confirmed the possible role of CYP-BM3 in endosulfan metabolism. Thus, our results show that the protein structure based in-silico approach can help us to understand and identify microbes for remediation strategy development. To the best of our knowledge this is the first report which has extrapolated the bacterial gene for endosulfan biotransformation through in silico prediction approach for metabolic gene identification.     

Assessment of groundwater quality in Kavaratti Island in the Lakshadweep Archipelagos,India

This study attempts to address the processes controlling the chemical composition of the Kavaratti aquifer system of Lakshadweep Island in India. Major ions and other physico-chemical parameters were determined for the premonsoon period in the Kavaratti of the Lakshadweep Island system. The trilinear diagram confirms the ingress of sea water into the shallow lens of freshwater in the islands by the changing water types. The abundance of major cations varied in the order Na>Ca>Mg>K and anions in the order Cl>HCO₃>SO₄. The ionic relations suggest that the higher concentration Na and Cl are the results of ion exchange and evaporation. The plots of data on the Gibbs diagram suggest that chemical weathering of rock-forming minerals and evaporation are the dominant factors controlling groundwater chemistry in the area. The hydrochemistry concept was deduced by the multivariate analysis for better understanding on the dynamic and complexity of the groundwater chemical processes. By the multivariate analytical techniques, the samples were grouped into two: one with saline water dominance and the other with freshwater characteristics. Thus proper management of these aquifers should be assured to retain their freshwater yield in the future.     

Assessment of heavy metals (Cd, Cr and Pb) in water, sediment and seaweed (Ulva lactuca) in the Pulicat Lake, South East India

The concentrations of three heavy metals chromium (Cr), cadmium (Cd) and lead (Pb) were examined in water, sediment and green algae (Ulva lactuca); collected from six different stations at Pulicat Lake, which receives effluents from industries located in North Chennai Coastal region. Concentrations of Cd (64.21 microg g(-1)) and Cr (28.51 microg g(-1)) were found to be high in sediment, whereas in green algae concentration of Pb (8.32 microg g(-1)) was higher than water and sediment samples. The relative abundance of these heavy metals in U. lactuca and sediment were found to be in the order Cd>Cr>Pb, whereas in water the ratio was found to be Cr>Pb>Cd. The seasonal variations in Cd and Pb followed a similar pattern in both seaweeds and sediments, but not in water samples. Spearman correlation coefficient study showed no significant correlation in the concentration of metals in U. lactuca, water and sediment samples.     

Hydrochemistry and dissolved nutrient flux of two small catchment rivers, south-western India

This paper deals with the water chemistry and dissolved nutrient flux of two small mountainous and heavily dammed rivers—Periyar and Chalakudy—of Kerala on the south-west coast of India. The lower reaches of these rivers are affected by sea-water ingression from the Arabian Sea during the non-monsoon season. Human interference through agriculture, urbanization, and industrialization in the lower and middle stretches of the river basins induces marked concentration variations in the hydro-chemical parameters. Except for N & P, all other chemical constituents exhibit high values during the non-monsoon season. Industrial contaminants in specific locations of the Periyar river reduce the pH to lower levels. Nutrients in the two rivers reveal marked seasonal and regional concentration variations. During the monsoon season, dissolved inorganic nitrogen (DIN) predominates over dissolved organic nitrogen (DON), but the reverse trend is observed during the non-monsoon season. The Periyar river shows higher average concentrations of DIN (monsoon 801 μg l^-1 and non-monsoon 292 μg l^-1) than Chalakudy river (monsoon 478 μg l^-1 and non-monsoon 130 μg l^-1). Dissolved inorganic phosphorus (DIP) has lower average values in the monsoon season (Periyar river, 38 μg l^-1; Chalakudy river, 42 μg l^-1) than dissolved organic phosphorus (DOP) values (Periyar river, 107 μg l^-1; Chalakudy, 62 μg l^-1). The rivers show a marked difference in nutrient flux due to its difference in water discharge/basin characteristics and point/non-point sources of contaminants. The flux rates of DIN, DIP, and DOP during the monsoon are higher than during the non-monsoon season, while those of dissolved silicon (DSi), dissolved Fe (DFe), and DON are lower. On average, the Periyar river discharges 4953 t y^-1 of DIN and 1626 t y^-1 of DON to the coastal waters, and the corres-ponding values of the Chalakudy river are 772 t y^-1 and 596 t y^-1. The Periyar and Chalakudy rivers discharge 245 t y^-1 and 70.8 t y^-1 of DIP, respectively. The total flux of DOP is considerably higher (Periyar river 703 t y^-1 and Chalakudy river 101 t y^-1). The discharge of DSi into the Periyar river (40 193 t y^-1) is nearly five times higher than that in the Chalakudy river (8275 t y^-1). The discharges of DFe through the Periyar and Chalakudy rivers are 257 t y^-1 and 36.7 t y^-1, respectively. To sum up, this study addresses the water quality and nutrient flux of two tropical rivers and discusses the impact of urbanization and industrialization on river-water quality.     

Hydrogeochemical study of shallow carbonate aquifers, Rameswaram Island, India

Groundwater quality assessment has been carried out based on physicochemical parameters (pH, EC, TDS, CO(3), HCO(3), Cl, SO(4), PO(4), NO(2), Ca(+2), Mg(+2), Na(+) and K(+)) and metal concentration in the Rameswaram Island from 25 bore wells. The Langelier Saturation Index of the groundwater shows positive values (63% samples) with a tendency to deposit the CaCO(3) in the majority of water samples. Scatter plot (Ca + Mg/HCO(3)) suggests carbonate weathering process, which is the main contributor of Ca(2+), Mg(2+) and HCO(3) ions to the water. Gibbs diagram suggests rock-water interaction dominance and evaporation dominance which are responsible for the change in the quality of water in the study area. NaCl and mixed CaNaHCO(3) facies are two main hydrogeochemical facies of groundwater. Mathematical calculations and graphical plots of geochemical data reveal that the groundwater of Rameswaram Island is influenced by natural weathering of rocks, anthropogenic activities and seawater intrusion due to over exploitation. Weathering and dissolution of carbonate and gypsum minerals also control the concentration of major ions (Ca(+2), Mg(+2), Na(+) and K(+)) in the groundwater. The nutrient concentration of groundwater is controlled to a large extent by the fertilizers used in agricultural lands and aquaforms. Comparison of geochemical data shows that majority of the groundwater samples are suitable for drinking water and irrigation purposes.     

Significance of autochthonous Bacillus sp. KK1 on biomineralization of lead in mine tailings

The aim of the study was to isolate and characterize potential autochthonous bacteria for biomineralization of Pb in mine tailings. A total of four bacteria were isolated from the soil samples and assayed for tolerance to Pb and other heavy metals. Isolate KK1 exhibited maximum Pb resistance and was subsequently identified as Bacillus sp. based on the partial 16S rRNA gene sequences. The isolate KK1 reduced the Pb ions and did not harbor pbrT gene. Selective sequential extraction of bioaugmented soil revealed that the isolate significantly reduced (26%) the exchangeable fraction and increased (38%) the carbonate fraction of Pb. X-ray diffraction studies confirmed the role of bacterially induced calcite precipitation in the bioremediation of mine tailings. A significant increase in the urease (334%), DHO (dehydrogenase) (14%), and phosphatase (37%) activity was observed in the bioaugmented mine soil.     

Cellular alterations and modulation of protein expression in bitumen-challenged human osteoblast cells

Purpose

There are many arguments on the carcinogenic potential of bitumen extract. The mechanism of bitumen-induced damage is not well understood at the molecular level. Therefore, in the present study, cell-transforming and tumor-inducing potential of bitumen extract was studied using in vitro [human osteosarcoma (HOS) cells] and in vivo [nude and severe combined immunodeficiency (SCID) mice] models.

Methods

Gas chromatography/mass spectrometry (GC/MS) analysis was carried out to find out the existence of carcinogenic compounds in the bitumen extract. Cell transformation test, anchorage independence assay, karyotyping assay, tumorigenicity assay, and 2-DE analysis were used to find out the effect of bitumen using the in vitro and in vivo models.

Results

GC/MS analysis showed the existence of carcinogenic compounds in the bitumen extract. HOS cells were treated with different concentrations (25, 50, and 100???l/ml) of bitumen extract. Compared to the parental HOS cells, bitumen transformants (HOS T1 and HOS T2) showed the characteristics of anchorage independency, chromosomal anomaly, and cellular transformation. Interestingly, bitumen transformants were not able to form tumor in nude/SCID mice. Proteomic analysis revealed the existence of 19 differentially expressed proteins involved in progression of cancer, angiogenesis, cell adhesion, etc.

Conclusions

Exposure of bitumen extract to HOS cells results in the cellular transformation similar to cancer cells and can modulate proteins involved in the progression of cancer. We state that the non-tumorogenic potential of bitumen transformant in nude/SCID mice can be attributed to the downregulation of galectin-1, chromodomain helicase DNA-binding protein 1-like gene, and membrane-associated guanylate kinase 2 protein.