Sivanesan Saravana Devi

Recent Advancements in Carbonic Anhydrase–Driven Processes for CO2 Sequestration: Minireview

The authors reviews the advancements in carbonic anhydrase– driven processes for CO2 sequestration research and engineering. Historical and recent discoveries of carbonic anhydrase and idea behind using it for CO2 sequestration are elaborated as well as the uses of this enzyme in free and immobilized forms are thoroughly discussed. New concepts such as extension of immobilized enzyme systems for bioreactor approach with the aim of CO2 abatement at the source are also introduced briefly toward the end of the review. The authors also suggest the possible future directions to employ carbonic anhydrase for CO2 sequestration.

Stress-induced lipids are unsuitable as a direct biodiesel feedstock: a case study with Chlorella pyrenoidosa.

The effects of various stresses on the suitability of lipid synthesized by Chlorella pyrenoidosa for biodiesel production were investigated. Lipids were characterized for detailed fatty acid methyl ester profiling and biodiesel properties like cetane number (CN), iodine value, cold filter plugging point (CFPP). Maximum biomass productivity (106.63 mgL(-1)d(-1)) and lipid content (29.68%) were obtained at indoor cultivation (nitrate sufficient, pH 8-10, 24h illumination). However, compared to this condition, other nitrate sufficient cultures [pH 6-8 and 10-12 (24h illumination), and at ambient CO2 and 16:8h light:dark photoperiod (pH unadjusted)] showed ∼12-14% lower lipid productivity. Upon 50% nitrate depletion (at indoor and outdoor; pH unadjusted) lipid content has increased by 7.62% and 17%, respectively. Though stress conditions helped enhancing lipid accumulation, there was two-fold increase in PUFA content compared to that observed at pH 8-10. This resulted in fuel properties which did not comply with the biodiesel standards.

Biological decolourization of C.I. Direct Black 38 by E. gallinarum.

In the present study, an Enterococcus gallinarum strain was isolated from effluent treatment plant of a textile industry based on its ability to decolourize C.I. Direct Black 38 (DB38), a benzidine-based azo dye. Effects of dye concentration and medium composition on dye decolourization were studied. The strain was found to decolourize DB38 even under aerobic conditions. Kinetics of DB38 decolourization was also examined, and V(max) and K(s) of decolourization were found to be higher in Luria broth (12.8 mg l(-1)h(-1) and 490.6 mg l(-1)) than in minimal medium (4.09 mg l(-1)h(-1) and 161.84 mg l(-1)). However, decolourization rate/biomass was found to be higher in minimal medium than in Luria broth, indicating greater decolourization efficiency of biomass in the former. The study also revealed biodegradation of DB38 to benzidine and its further deamination to 4-aminobiphenyl (4-ABP) by the culture. Ammonia released during this process was used as nitrogen source for growth of the culture.

Heavy Metal Status and Oxidative Stress in Diesel Engine Tuning Workers of Central Indian Population

Objective: To assess the oxidative stress induced due to heavy metal exposure. Exposed populations are selected from an engine tuning station and control from the same area with no occupational exposure. Method: Standard methods were followed for enzymatic assay, and heavy metals in blood and urine were analyzed by using inductively coupled plasma-optical emission spectrophotometer after microwave digestion. Result: Changes in mean blood Pb, Cd, and Ni concentrations in blood and urine of exposed population of all age groups (20 to 35, 35 to 45, and 46 to 58 years) and exposure durations (≤10, 11 to 20, and >20 years) were statistically not significant. However, exposed workers exhibited statistically significant higher antioxidant status in terms of serum glutathione-S-transferase activity, malondialdehyde level, and catalase activity. Conclusion: The findings in this article suggest that occupational exposure to diesel exhaust of engine tuning workers causes induction of oxidative stress, which cannot be correlated with the heavy metals status in blood and urine of an exposed population.

Gymnema montanum H. Protects Against Alloxan-induced Oxidative Stress and Apoptosis in Pancreatic β-cells

The present study evaluated the molecular mechanism of antidiabetic property of G. montanum leaf extract (GLEt) against alloxan-induced apoptotic cell death in rat insulinoma cells (RINm5F). The pre-treatment of GLEt (5 μg and 10 μg/ml) resulted in significant decrease in intracellular Ca2+ concentration, nitric oxide (NO) production along with increase in mitochondrial membrane potential in alloxan (7mM/ml) treated cells. Further GLEt reduced apoptosis by inhibiting the release of cytochrome c and subsequent cleavage of PARP and caspase-3. The immunochemical staining of 8-hydroxydeoxyguanosine (8-OHdG) also evidenced the suppression of oxidative stress by GLEt. The cell cycle analysis, annexin-V labelling assay and TUNEL assay showed the suppression of apoptosis by the treatment of GLEt. Moreover, GLEt significantly increased the cellular antioxidant levels and decreased the lipid peroxides in alloxan-treated RINm5F cells. Taken together, these findings suggest that G. montanum protects pancreatic β-cells against reactive oxygen species (ROS) by counteracting with mitochondrial membrane permeability and inhibition of the apoptotic pathway.

Carvacrol induces mitochondria-mediated apoptosis in HL-60 promyelocytic and Jurkat T lymphoma cells.

The aim of the present study was to investigate the effect of carvacrol, a phenolic monoterpenoid on the induction of apoptosis in HL-60 (Human acute promyelocytic leukemia cells) and Jurkat (human T lymphocyte cells) cells. Carvacrol showed a potent cytotoxic effect on both cells with dose-dependent increase in the level of free radical formation as measured by an oxidation sensitive fluorescent dye, 2,7-dichlorodihydrofluorescein diacetate (H2DCFDA) levels. The reduction in the level of antioxidants such as catalase (CAT) and superoxide dismutase (SOD) (P<0.05) was observed in carvacrol-treated cells. The major cytotoxic effect appears to be intervened by the induction of apoptotic cell death as assessed by annexin-V labeling assay using flow cytometry. Western blot analysis showed that Bax expression was increased, whereas Bcl-2 expression was significantly decreased in carvacrol exposed HL-60 cells and Jurkat cells. Further studies revealed that the dissipation of mitochondrial membrane potential of intact cells was accompanied by the activation of caspase-3. Our results found that the potential mechanism of cellular apoptosis induced by carvacrol is mediated by caspase-3 and is associated with the collapse of mitochondrial membrane potential, generation of free radicals, and depletion of the intracellular antioxidant pool.

Genetic polymorphism of CYP2D6*2 C → T 2850, GSTM1, NQO1 genes and their correlation with biomarkers in manganese miners of Central India

Manganese (Mn) intoxication is most often regarded as an occupational manifestation and occurs in places such as manganese mines, dry cell battery plants and ceramic industries. In the present study, the influence of genetic polymorphism in cytochrome P450 2D6 (CYP2D6∗2), glutathione S-transferase M1 (GSTM1) and NAD(P)H quinone oxidoreductase 1 (NQO1) genes on blood manganese and plasma prolactin concentrations in manganese miners was investigated. Genotyping of CYP2D6∗2 C→T 2850 and NQO1 C→T 609 was carried out using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) whereas the genotyping of GSTM1 was carried out by multiplex PCR using beta globin as an internal control. Manganese miners with CYP2D6∗2 C→T 2850 variant genotype had relatively low Mn concentration [GM: 21.4±8.9 μg L(-1)] than the subjects with wild (GM: 36.3±8.5 μg L(-1)) and heterozygous (GM: 34.4±6.9 μg L(-1)) genotypes. Miners with CYP2D6∗2 variant genotypes showed low prolactin levels (GM: 13.13±1.6 ng mL(-1)) compared to the wild (GM: 16.4.4±1.5 μg L(-1)) and heterozygous (GM: 18.7±1.6 ng mL(-1)) genotypes. Gene-gene interaction studies also revealed that the subjects with CYP2D6∗2 C→T 2850 variant genotypes had low levels of Mn and prolactin. Our new findings suggest that CYP2D6∗2 C→T 2850 variant genotypes can regulate plasma prolactin levels in manganese miners of Central India and could be involved in the fast metabolism of blood manganese, compared to wild and heterozygous genotypes.

Biomass and lipid enhancement in Chlorella sp. with emphasis on biodiesel quality assessment through detailed FAME signature.

In this study, the concentrations of MgSO4, salinity and light intensity were optimised for maximum biomass productivity and lipid content in Chlorella sp. Lipid synthesized at varied experimental conditions was also assessed in detail for biodiesel properties through FAME analysis. FAMEs mainly composed of C16:0, C16:1(9), C16:3(7, 10, 13), C18:0, C18:1(11), C18:2(9, 12), C18:3(9, 12, 15). The optimum biomass productivity (372.50mgL(-1)d(-1)) and lipid content (32.57%) was obtained at MgSO4-150ppm; salinity-12.5ppm, and light intensity-25μmolm(-2)s(-1). However, at this condition the cetane number, a major biodiesel property was not complying with worldwide biodiesel standard. Therefore, further optimisations were done to check the suitability of biodiesel fuel. The optimum biomass productivity (348.47mgL(-1)d(-1)) and lipid content (12.43%) with suitable biodiesel fuel properties was obtained at MgSO4-50ppm, salinity-25ppm and light intensity-100μmolm(-2)s(-1). The validation experiments confirmed the closeness of predicted and measured response values.

Microorganism-assisted phytoremediation of heavy metal and endosulfan contaminated soil.

*Corresponding author: Tapan Chakrabarti, Council of Scientific and Industrial Research-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur 440020, India, E-mail: tapan1249@gmail.com S.K. Yadav, A.A. Juwarkar, A.B. Balki, A.R. Shende, S.S. Devi, K. Krishnamurthi, A. Bafna and Rajendra Prasad: Council of Scientific and Industrial Research-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur, India