Characterization of midgut trypsinogen-like cDNA and enzymatic activity in Plutella xylostella parasitized by Cotesia vestalis or Diadegma semiclausum.
Characterization of midgut trypsinogen-like cDNA and enzymatic activity in Plutella xylostella parasitized by Cotesia vestalis or Diadegma semiclausum.
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DOI：
10.1002/arch.20249
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发表时间：
2009
影响因子：
2.2
通讯作者：
M. Shi;F. Huang;Ya-Feng Chen;Xiangguang Meng;Xue-xin Chen
中科院分区：
文献类型：
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作者：
M. Shi;F. Huang;Ya-Feng Chen;Xiangguang Meng;Xue-xin Chen
昆虫的蛋白质消化是存在于中肠中的蛋白酶复合物作用的结果。在这份报告中，我们描述了一个胰蛋白酶cDNA的克隆和测序的鳞翅目草食性小菜蛾幼虫。研究了该基因在小菜蛾幼虫体内的表达及其以N-α-苯甲酰-L-精氨酸对硝基苯胺（BApNA）为底物的翻译产物的酶活性。该基因的cDNA全长由一个开放阅读框（ORF）组成，编码273个氨基酸残基，其中23个为信号肽残基，预测的成熟胰蛋白酶样酶分子量为26.5 kDa。该蛋白的氨基酸序列及其与已发表的胰蛋白酶蛋白的亲缘关系表明，该蛋白可能是胰蛋白酶家族中的一种新蛋白酶。寄生性D. semiclausum没有显着改变寄主幼虫的mRNA转录水平或BApNAase活性。而C. vestalis诱导更高的转录水平与更高水平的BApNAase活性相结合。未寄生和寄生小菜蛾幼虫中肠的BApNAase活性在pH 12时均达到最大值，而寄生小菜蛾幼虫和未寄生小菜蛾幼虫中肠的BApNAase活性在pH 12时均达到最大值。vestalis和D. semiclausum增加了酶的敏感性，pH值范围从2到9.5。这些寄生虫引起的变化可能代表主机操纵发育中的寄生虫幼虫。
Protein digestion in insects is a result of the action of a complex of proteinases present in the midgut. In this report we describe the cloning and sequencing of a trypsin cDNA from larvae of the lepidopteran herbivore Plutella xylostella. We investigated the expression of this gene and enzymatic activity of its translation product with N-a-benzoyl-l-arginine p-nitroanilide (BApNA) as substrate in P. xylostella larvae that were either unparasitized or parasitized by Cotesia vestalis or Diadegma semiclausum parasitoids. The full cDNA sequence consisted of an open reading frame (ORF) encoding 273 amino acid residues including 23 residues of a signal peptide, and the predicted mature trypsinogen-like enzyme had a molecular mass of 26.5 kDa. The amino acid sequence of this trypsinogen-like enzyme protein and phylogenetic relationship with other published trypsin enzyme proteins suggested that it may be a new proteinase in the trypsin protein family. Parasitism of D. semiclausum did not significantly change the mRNA transcript level or BApNAase activity in host larvae. By contrast, parasitization by C. vestalis induced higher transcript levels coupled with a higher level of BApNAase activity. The BApNAase activity in the midgut of nonparasitized or parasitized P. xylostella larvae increased to a maximum level at pH 12, and the parasitism by both C. vestalis and D. semiclausum increased sensitivity of the enzyme to pH values ranging from 2 to 9.5. These parasitoid-induced changes may represent host manipulation by the developing parasitoid larva.