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Neonicotinoids are the most important class of insecticides used in agriculture over the last decade. They act as selective agonists of insect nicotinic acetylcholine receptors (nAChRs). The emergence of insect resistance to these insecticides is one of the major problems, which limit the use of neonicotinoids. The aim of our study is to better understand physiological changes appearing after subchronic exposure to sublethal doses of insecticide using complementary approaches that include toxicology, electrophysiology, molecular biology and calcium imaging. We used cockroach neurosecretory cells identified as dorsal unpaired median (DUM) neurons, known to express two a-bungarotoxin-insensitive (a-bgt-insensitive) nAChR subtypes, nAChR1 and nAChR2, which differ in their sensitivity to imidacloprid. Although nAChR1 is sensitive to imidacloprid, nAChR2 is insensitive to this insecticide. In this study, we demonstrate that subchronic exposure to sublethal dose of imidacloprid differentially changes physiological and molecular properties of nAChR1 and nAChR2. Our findings reported that this treatment decreased the sensitivity of nAChR1 to imidacloprid, reduced current density flowing through this nAChR subtype but did not affect its subunit composition (a3, a8 and b1). Subchronic exposure to sublethal dose of imidacloprid also affected nAChR2 functions. However, these effects were different from those reported on nAChR1. We observed changes in nAChR2 conformational state, which could be related to modification of the subunit composition (a1, a2 and b1). Finally, the subchronic exposure affecting both nAChR1 and nAChR2 seemed to be linked to the elevation of the steady-state resting intracellular calcium level. In conclusion,under subchronic exposure to sublethal dose of imidacloprid, cockroaches are capable of triggering adaptive mechanisms by reducing the participation of imidacloprid-sensitive nAChR1 and by optimizing functional properties of nAChR2, which is insensitive to this insecticide.

SOIL contaminated with heavy metals negatively affects both the groundwater quality and the food production system. Heavy metals can be remediated from contaminated soil by phytoextraction. This study aims to illustrate the possible use of barley genotypes as a cheap, effective, safe and sustainable way to remediate contaminated soil. A set of 17 genotypes, including Egyptian and German varieties and wild accessions were sown under heavy metals contaminated and uncontaminated soil in a potted experiment for two years (2015/2016 and 2016/2017). Heavy metals concentrations including Al, Cr, Cu, Fe, Ni and Zn were measured in grains and leaves, separately, for each genotype under contaminated and uncontaminated soils. Results showed that genotypes differed in their capability to accumulate different heavy metals in either grains or leaves. In addition, there were significant positive correlations between Al, Cr, Cu and Zn concentrations in grains under uncontaminated and contaminated soils. In conclusion, mixture of barley’s genotypes including Heines-Hanns, ICB 180410, Giza-126, Giza-129, Giza-130, Giza-2000, Pasadena and Barke might be used to remediate contaminated soil

SOIL contaminated with heavy metals negatively affects both the groundwater quality and the food production system. Heavy metals can be remediated from contaminated soil by phytoextraction. This study aims to illustrate the possible use of barley genotypes as a cheap, effective, safe and sustainable way to remediate contaminated soil. A set of 17 genotypes, including Egyptian and German varieties and wild accessions were sown under heavy metals contaminated and uncontaminated soil in a potted experiment for two years (2015/2016 and 2016/2017). Heavy metals concentrations including Al, Cr, Cu, Fe, Ni and Zn were measured in grains and leaves, separately, for each genotype under contaminated and uncontaminated soils. Results showed that genotypes differed in their capability to accumulate different heavy metals in either grains or leaves. In addition, there were significant positive correlations between Al, Cr, Cu and Zn concentrations in grains under uncontaminated and contaminated soils. In conclusion, mixture of barley’s genotypes including Heines-Hanns, ICB 180410, Giza-126, Giza-129, Giza-130, Giza-2000, Pasadena and Barke might be used to remediate contaminated soil

THIS RESEARCH was conducted to study the effects of late planting on the performance of Egyptian cotton sensitivity to the environment, and gene actions that controlling seed cotton yield/plant (SCY/P) and related traits. Half diallel crosses of eight Egyptian cotton varieties were evaluated under early and late plantings. The analysis of variance indicated significant (p ≤ 0.01) differences among entries (parents and crosses) for most traits. The reduction percentin seed SCY/P caused by the stress of late planting was 17.98 and 18.25 percent for the parents and hybrids; respectively. Stress susceptibility index indicated that five parents were tolerant for SCY/P to late planting. Fifteen out of the 28 hybrids showed tolerance in SCY/P to late planting. The diallel analysis of variance indicated that both additive and dominance effects of genes were involved in the inheritance of all traits. Generally, the regression coefficient “b Wr/Vr” and the graphical analysis revealed that the inheritance of seed cotton yield/plant controlled by additive, dominance and epistatic effects of genes. The results of boll weight under the stress of late planting suggested the presence of additive, dominance and epistatic genes interaction. The genetic analysis of number of seeds/boll under late planting indicated no significance of the additive effects of genes “a item”, however, the dominance item “b” was significant (p≤ 0.01). The non-additive effects of genes were reflected in the departure of narrow from broad sense heritability. Therefore, pedigree and recurrent selection breeding methods could be effective in isolating lines adapted to late planting.

THIS RESEARCH was conducted to study the effects of late planting on the performance of Egyptian cotton sensitivity to the environment, and gene actions that controlling seed cotton yield/plant (SCY/P) and related traits. Half diallel crosses of eight Egyptian cotton varieties were evaluated under early and late plantings. The analysis of variance indicated significant (p ≤ 0.01) differences among entries (parents and crosses) for most traits. The reduction percentin seed SCY/P caused by the stress of late planting was 17.98 and 18.25 percent for the parents and hybrids; respectively. Stress susceptibility index indicated that five parents were tolerant for SCY/P to late planting. Fifteen out of the 28 hybrids showed tolerance in SCY/P to late planting. The diallel analysis of variance indicated that both additive and dominance effects of genes were involved in the inheritance of all traits. Generally, the regression coefficient “b Wr/Vr” and the graphical analysis revealed that the inheritance of seed cotton yield/plant controlled by additive, dominance and epistatic effects of genes. The results of boll weight under the stress of late planting suggested the presence of additive, dominance and epistatic genes interaction. The genetic analysis of number of seeds/boll under late planting indicated no significance of the additive effects of genes “a item”, however, the dominance item “b” was significant (p≤ 0.01). The non-additive effects of genes were reflected in the departure of narrow from broad sense heritability. Therefore, pedigree and recurrent selection breeding methods could be effective in isolating lines adapted to late planting.