[en] Highlights: • Energy use efficiency (EUE), Greenhouse gases (GHGs) emission and carbon footprints (CF) were analysed. • Irrigation water contribute maximum (41–44%) share of input energy followed chemical fertilizers (32–40%). • Conservation tillage and residue management enhanced energy productivity (15.8–21.0%) and EUE (17.1–22.4%). • The CF lowered by 77.9% in zero tillage with residue to 45.2% in reduced tillage without residue. • Zero tillage with residue addition is most energy efficient system with lower GHG emission and carbon footprint. Conventional rice-wheat cropping system (RWCS) in western Indo-Gangetic Plains (IGP) is carbon and energy intensive. A field experiment was conducted to evaluate energy budgeting, carbon footprints (CF) and greenhouse gas (GHG) emissions from RWCS under long-term tillage and residue management practices. Experiment consisted six treatment combination of tillage [conventional tillage (CT), reduced tillage (RT) and zero tillage (ZT)] and residue [with residue (+R) and without residue (–R)] namely (i) CT-R (conventional farmers’ practice), (ii) CT + R, (iii) RT-R, (iv) RT + R, (v) ZT-R and (vi) ZT + R. Energy consumption ranged from 51.87 GJ ha⁻¹ (ZT-R) to 64.91 GJ ha⁻¹ (CT + R) and irrigation water was major energy intensive input (41–44%) followed by chemical fertilizer (32–40%). Compared to CT-R, energy use efficiency (EUE) increased by 8.7–22.4%, CF lowered by 77.9–34.3%, and GHG emission lowered by 12.8–16.3% in different treatments. Residue addition enhanced the soil carbon accumulation in ZT + R (1213 kg C ha⁻¹ yr⁻¹) and RT + R (987 kg C ha⁻¹ yr⁻¹). Overall, switching from CT–R to ZT + R lowered energy consumption (19%), GHG emission (16%) and CF (78%), making it best-bet option for climate change mitigation and global warming related environmental protection in western IGP and similar agro–ecologies.

[en] Organophosphate pesticides (OPs) are primarily metabolized by several xenobiotic metabolizing enzymes (XMEs). Very few studies have explored genetic polymorphisms of XMEs and their association with DNA damage in pesticide-exposed workers. The present study was designed to determine the role of genetic polymorphisms of CYP1A1, CYP3A5, CYP2C9, CYP2D6, and PON1 in the modulation of DNA damage in workers occupationally exposed to OPs. We examined 284 subjects including 150 workers occupationally exposed to OPs and 134 normal healthy controls. The DNA damage was evaluated using the alkaline comet assay and genotyping was done using PCR–RFLP. The results revealed that the PONase activity toward paraoxonase and AChE activity was found significantly lowered in workers as compared to control subjects (p < 0.001). Workers showed significantly higher DNA damage compared to control subjects (14.37 ± 2.15 vs. 6.24 ± 1.37 tail% DNA, p < 0.001). Further, the workers with CYP2D6*3 PM and PON1 (QQ and MM) genotypes were found to have significantly higher DNA damage when compared to other genotypes (p < 0.05). In addition, significant increase in DNA damage was also observed in workers with concomitant presence of certain CYP2D6 and PON1 (Q192R and L55M) genotypes which need further extensive studies. In conclusion, the results indicate that the PON1 and CYP2D6 genotypes can modulate DNA damage elicited by some OPs possibly through gene-environment interactions. -- Highlights: ► Role of CYP1A1, CYP3A5, CYP2C, CYP2D6 and PON1 genotypes on DNA damage. ► Workers exposed to some OPs demonstrated increased DNA damage. ► CYP2D6 *3 PM and PON1 (Q192R and L55M) genotypes are associated with DNA damage. ► Concomitant presence of certain CYP2D6 and PON1 genotypes can increase DNA damage.

[en] Human paraoxonase 1 (PON1) is a lipoprotein-associated enzyme involved in the detoxification of organophosphate pesticides (OPs) by hydrolyzing the bioactive oxons. Polymorphisms of the PON1 gene are responsible for variation in the expression and catalytic activity of PON1 enzyme. In the present study, we have determined (a) the prevalence of two common PON1 polymorphisms, (b) the activity of PON1 and acetylcholinesterase enzymes, and (c) the influence of PON1 genotypes and phenotypes variation on DNA damage in workers exposed to OPs. We examined 230 subjects including 115 workers exposed to OPs and an equal number of normal healthy controls. The results revealed that PON1 activity toward paraoxon (179.19 ± 39.36 vs. 241.52 ± 42.32 nmol/min/ml in controls) and phenylacetate (112.74 ± 17.37 vs. 134.28 ± 25.49 μmol/min/ml in controls) was significantly lower in workers than in control subjects (p < 0.001). No significant difference was observed in the distribution of genotypes and allelic frequencies of PON1₁₉₂QR (Gln/Arg) and PON1₅₅LM (Leu/Met) in workers and control subjects (p > 0.05). The PON1 activity toward paraoxonase was found to be significantly higher in the R/R (Arg/Arg) genotypes than Q/R (Gln/Arg) and lowest in Q/Q (Gln/Gln) genotypes in both workers and control subjects (p < 0.001). For PON1₅₅LM (Leu/Met), PON1 activity toward paraoxonase was observed to be higher in individuals with L/L (Leu/Leu) genotypes and lowest in individuals with M/M (Met/Met) genotypes in both groups (p < 0.001). No influence of PON1 genotypes and phenotypes was seen on the activity of acetylcholinesterase and arylesterase. The DNA damage was observed to be significantly higher in workers than in control subjects (p < 0.05). Further, the individuals who showed least paraoxonase activity i.e., those with (Q/Q [Gln/Gln] and M/M [Met/Met]) genotypes showed significantly higher DNA damage compared to other isoforms in workers exposed to OPs (p < 0.05). The results indicate that the individuals with PON1 Q/Q and M/M genotypes are more susceptible toward genotoxicity. In conclusion, the study suggests wide variation in enzyme activities and DNA damage due to polymorphisms in PON1 gene, which might have an important role in the identification of individual risk factors in workers occupationally exposed to OPs.