A crucial enzyme in feeding and survival of Lymantria dispar (gypsy moth) caterpillars is β-glucosidase. Considering that this herbivorous species is one of the most damaging pests, a study of the enzyme that hydrolyzes plant polysaccharides is of invaluable significance. The knowledge of glucosidase alterations helps clarify our understanding of the insect pest feeding strategy in highly polluted environments. We sought to find out whether acute and chronic exposures to cadmium (10 and 30 mg Cd/g dry food), as well as the recovery from long-term treatment, influence the specific activity of midgut β-glucosidase. Cadmium ingestion did not alter enzyme activity compared to control, regardless of the treatment duration and metal concentration. The only statistically significant increase in enzyme activity was detected during the recovery after chronic treatment at 10 mg Cd/g dry food compared to the chronic cadmium effect at the same metal concentration. During chronic treatment at a lower cadmium concentration (10 mg Cd/g dry food), the phenotypic plasticity index was higher than at the recovery from the same concentration, while the variability of plasticity among these treatments was higher after recovery. Only one enzyme isoform was detected, which indicates its ability to hydrolyze several substrates. We concluded that this enzyme is probably essential for larval nutrition and survival in the presence of high amounts of cadmium in the food.

中文翻译：

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日粮中镉摄入量对Lymantria dispar幼虫中肠β-葡萄糖苷酶的影响

在 Lymantria dispar (gypsy moth) 毛虫的摄食和存活过程中，一种关键的酶是 β-葡萄糖苷酶。考虑到这种食草物种是最具破坏性的害虫之一，对水解植物多糖的酶的研究具有非常重要的意义。葡萄糖苷酶改变的知识有助于阐明我们对高度污染环境中害虫取食策略的理解。我们试图找出急性和慢性镉暴露（10 和 30 毫克镉/克干粮）以及长期治疗后的恢复是否会影响中肠 β-葡萄糖苷酶的比活性。与对照相比，无论处理持续时间和金属浓度如何，摄入镉都不会改变酶活性。与相同金属浓度下的慢性镉效应相比，在以 10 毫克 Cd/g 干粮长期处理后的恢复期间，检测到酶活性的唯一统计显着增加。在较低镉浓度（10 mg Cd/g干粮）慢性处理期间，表型可塑性指数高于从相同浓度恢复时的表型可塑性指数，而恢复后这些处理之间的可塑性变异性更高。仅检测到一种酶同种型，这表明它具有水解多种底物的能力。我们得出的结论是，在食物中存在大量镉的情况下，这种酶可能对幼虫的营养和存活至关重要。在较低镉浓度（10 mg Cd/g干粮）慢性处理期间，表型可塑性指数高于从相同浓度恢复时的表型可塑性指数，而恢复后这些处理之间的可塑性变异性更高。仅检测到一种酶同种型，这表明它具有水解多种底物的能力。我们得出的结论是，在食物中存在大量镉的情况下，这种酶可能对幼虫的营养和存活至关重要。在较低镉浓度（10 mg Cd/g干粮）的慢性处理期间，表型可塑性指数高于相同浓度恢复时的表型可塑性指数，而恢复后这些处理之间的可塑性变异性更高。仅检测到一种酶同种型，这表明它具有水解多种底物的能力。我们得出的结论是，在食物中存在大量镉的情况下，这种酶可能对幼虫的营养和存活至关重要。