De Oliveira Neto Osmundo Brilhante, Batista João Aguiar Nogueira, Rigden Daniel John, Franco Octávio Luiz, Fragoso Rodrigo Rocha, Monteiro Ana Carolina Santos, Monnerat Rose Gomes, Grossi-De-Sa Maria Fátima
Embrapa Recursos Genéticos e Biotecnologia, Parque Estação Biológica, Final W5, Brasília, Brazil.
Biosci Biotechnol Biochem. 2004 Jun;68(6):1235-42. doi: 10.1271/bbb.68.1235.
The cotton boll weevil (Anthonomus grandis) causes severe cotton crop losses in North and South America. This report describes the presence of cysteine proteinase activity in the cotton boll weevil. Cysteine proteinase inhibitors from different sources were assayed against total A. grandis proteinases but, unexpectedly, no inhibitor tested was particularly effective. In order to screen for active inhibitors against the boll weevil, a cysteine proteinase cDNA (Agcys1) was isolated from A. grandis larvae using degenerate primers and rapid amplification of cDNA ends (RACE) techniques. Sequence analysis showed significant homologies with other insect cysteine proteinases. Northern blot analysis indicated that the mRNA encoding the proteinase was transcribed mainly in the gut of larvae. No mRNA was detected in neonatal larvae, pupae, or in the gut of the adult insect, suggesting that Agcys1 is an important cysteine proteinase for larvae digestion. The isolated gene will facilitate the search for highly active inhibitors towards boll weevil larvae that may provide a new opportunity to control this important insect pest.
棉铃象甲（Anthonomus grandis）在北美洲和南美洲造成棉花作物严重减产。本报告描述了棉铃象甲中半胱氨酸蛋白酶活性的存在情况。针对棉铃象甲的总蛋白酶对来自不同来源的半胱氨酸蛋白酶抑制剂进行了检测，但出乎意料的是，所测试的抑制剂均没有特别显著的效果。为了筛选针对棉铃象甲的活性抑制剂，使用简并引物和cDNA末端快速扩增（RACE）技术从棉铃象甲幼虫中分离出一个半胱氨酸蛋白酶cDNA（Agcys1）。序列分析表明其与其他昆虫半胱氨酸蛋白酶具有显著同源性。Northern印迹分析表明，编码该蛋白酶的mRNA主要在幼虫肠道中转录。在新生幼虫、蛹或成虫肠道中未检测到mRNA，这表明Agcys1是幼虫消化过程中的一种重要半胱氨酸蛋白酶。分离出的基因将有助于寻找对棉铃象甲幼虫具有高活性的抑制剂，这可能为控制这种重要害虫提供新的机会。
