Legume seed vicilins (7S storage proteins) interfere with the development of the cowpea weevil (Callosobruchus maculatus (F))

Vicilins (7S storage proteins) isolated from the seeds of the legumes Vigna unguiculata (cowpea), Vigna angularis (adzuki bean), Canavalia ensiformis (jack bean), Glycine max (soybean), Phaseolus vulgaris (common bean) and Phaseolus lunatus (lima bean) were shown to be immunologically related and to bind to a chitin matrix. The effect of the isolated vicilins on the development of the cowpea weevil Callosobruchus maculatus was examined. Vicilins from all non-host seeds, including those of the C maculatus-resistant cowpea line IT81D-1045, strongly inhibited larval development (ED₅₀ of 1·07±0·32% to 2·22±0·64%). Vicilins from the C maculatus-susceptible cowpea CE-31 and adzuki bean seeds were the exception with ED₅₀ of 6·25±0·75% and 5·40±1·54%, respectively. These results correlate well with the host range of C maculatus and are possibly a reflection of the low digestibility of vicilins by insect midgut proteinases in addition to the ability they show in binding to chitin-containing structures like the ones found in the bruchid midguts. © 1998 SCI.     

豇豆中灭蝇胺残留分析与膳食风险评估

该文建立了一种简便、快速、准确的豇豆中灭蝇胺残留的液相色谱-串联质谱分析方法，优化了提取溶剂等提取条件，以乙腈（含15%乙酸，V%）为提取溶剂，利用QuEChERS法进行净化。结果表明，该方法线性范围0.005~1.00 mg/L，检出限为0.001 mg/kg，定量限为0.010 mg/kg。0.010、0.10、0.50、1.00 mg/kg 4个添加水平的回收率为76.2%~82.8%，相对标准偏差为1.0%~5.7%，满足农药残留分析的要求。采用该方法分析了本地市场上112个豇豆样品，灭蝇胺的检出比例为22.3%，超标比例4.5%。长期膳食风险评估结果表明，灭蝇胺的风险熵RQ为10.74%，不会对一般人群健康造成不可接受的风险。在室温（约20 ℃）或冷藏（4 ℃）贮藏条件下，灭蝇胺在豇豆样品中的残留消解动态规律符合一级动力学方程，消解半衰期分别为5.0和7.2 d。存放温度、存放时间均对豇豆中灭蝇胺的残留变化有影响，较高的温度有利于残留值降低。