Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan, Canada.
Arch Insect Biochem Physiol. 2010 Oct;75(2):70-91. doi: 10.1002/arch.20381.
The midgut protease profiles from 5th instar Mamestra configurata larvae fed various diets (standard artificial diet, low protein diet, low protein diet with soybean trypsin inhibitor [SBTI], or Brassica napus) were characterized by one-dimensional enzymography in gelatin gels. The gut protease profile of larvae fed B. napus possessed protease activities of molecular masses of approximately 33 and 55 kDa, which were not present in the guts of larvae fed artificial diet. Similarly, larvae fed artificial diet had protease activities of molecular masses of approximately 21, 30, and 100 kDa that were absent in larvae fed B. napus. Protease profiles changed within 12 to 24 h after switching larvae from artificial diet to plant diet and vice versa. The gut protease profiles from larvae fed various other brassicaceous species and lines having different secondary metabolite profiles did not differ despite significant differences in larval growth rates on the different host plants. Genes encoding putative digestive proteolytic enzymes, including four carboxypeptidases, five aminopeptidases, and 48 serine proteases, were identified in cDNA libraries from 4th instar M. configurata midgut tissue. Many of the protease-encoding genes were expressed at similar levels on all diets; however, three chymoptrypsin-like genes (McSP23, McSP27, and McSP37) were expressed at much higher levels on standard artificial diet and diet containing SBTI as was the trypsin-like gene McSP34. The expression of the trypsin-like gene McSP50 was highest on B. napus. The adaptation of M. configurata digestive biochemistry to different diets is discussed in the context of the flexibility of polyphagous insects to changing diet sources.
用明胶凝胶进行一维酶谱法分析,研究了 5 龄期烟夜蛾幼虫在摄入不同食物(标准人工饲料、低蛋白饲料、含大豆胰蛋白酶抑制剂的低蛋白饲料或油菜)后的中肠蛋白酶图谱。摄入油菜的幼虫肠道中的蛋白酶谱具有约 33 和 55 kDa 分子量的蛋白酶活性,而摄入人工饲料的幼虫肠道中则没有这种活性。同样,摄入人工饲料的幼虫具有约 21、30 和 100 kDa 分子量的蛋白酶活性,而摄入油菜的幼虫肠道中则没有这种活性。幼虫从人工饲料切换到植物饲料后,12 到 24 小时内肠道蛋白酶谱会发生变化,反之亦然。尽管幼虫在不同的寄主植物上的生长速度存在显著差异,但摄入不同的芸薹属植物和具有不同次生代谢产物图谱的品系的幼虫肠道蛋白酶谱并没有差异。从 4 龄期烟夜蛾中肠组织的 cDNA 文库中鉴定出了编码潜在消化蛋白酶的基因,包括 4 个羧肽酶、5 个氨肽酶和 48 个丝氨酸蛋白酶。许多蛋白酶编码基因在所有饲料上的表达水平相似;然而,3 个糜蛋白酶样基因(McSP23、McSP27 和 McSP37)在标准人工饲料和含 SBTI 的饲料中的表达水平要高得多,胰蛋白酶样基因 McSP34 也是如此。胰蛋白酶样基因 McSP50 在油菜中的表达水平最高。根据多食性昆虫对不同食物来源的变化的适应性的灵活性,讨论了烟夜蛾消化生物化学对不同食物的适应。