Fitches E, Gatehouse J A.
Crop Protection Group, Plant Molecular Biology Section, Department of Biological Sciences, University of Durham, South, Road, Durham, UK
J Insect Physiol. 1998 Dec;44(12):1213-1224. doi: 10.1016/s0022-1910(98)00090-0.
When fed in semi-artificial diet in short- and long-term bioassays, the lectins from snowdrop (Galanthus nivalis; GNA) and jackbean (Canavalia ensiformis; Con A) affected the activities of soluble and brush border membrane (BBM) enzymes in the midgut of Lacanobia oleracea larvae. In the short term both lectins increased gut protein levels and BBM aminopeptidase activity. The lectins also increased trypsin activity, both in the gut (Con A) and in the faeces (GNA). GNA also increased the activity of alpha-glucosidase, but neither lectin had a significant effect on alkaline phosphatase activity. Trypsin mRNA levels were similar in lectin-fed and control larvae in the short term, showing that there is no direct effect on expression of the encoding genes. Larvae chronically exposed to GNA and Con A showed reductions in weight of 50-60%, and exhibited a significant reduction in alpha-glucosidase activity, but little change in other enzyme activities. Con A bound to many BBM and peritrophic matrix (PM) proteins in vitro, whereas GNA showed more specific binding, with strongest binding to a 94kDa uncharacterised BBM protein. Both lectins accumulated in gut tissues of insects after chronic exposure in vivo, but Con A was present at higher levels than GNA.
在短期和长期生物测定中，以半人工饲料喂养时，雪花莲（Galanthus nivalis；GNA）和刀豆（Canavalia ensiformis；Con A）中的凝集素影响了甘蓝夜蛾幼虫中肠中可溶性酶和刷状缘膜（BBM）酶的活性。短期内，两种凝集素都提高了肠道蛋白质水平和BBM氨肽酶活性。凝集素还提高了胰蛋白酶活性，在肠道中（Con A）以及粪便中（GNA）均有此效果。GNA还提高了α-葡萄糖苷酶的活性，但两种凝集素对碱性磷酸酶活性均无显著影响。短期内，喂食凝集素的幼虫和对照幼虫的胰蛋白酶mRNA水平相似，表明对编码基因的表达没有直接影响。长期暴露于GNA和Con A的幼虫体重减轻了50 - 60%，α-葡萄糖苷酶活性显著降低，但其他酶活性变化不大。Con A在体外与许多BBM和围食膜（PM）蛋白结合，而GNA表现出更具特异性的结合，与一种94kDa的未鉴定BBM蛋白结合最强。在体内长期暴露后，两种凝集素都在昆虫的肠道组织中积累，但Con A的含量高于GNA。
