Molecular Mechanisms of Insect Immunity

(1)诱导抗菌蛋白所需的肽聚糖的最小结构。制备了不同肽桥结构或不同链长的肽聚糖片段，并测试了其在家蚕体内诱导抗菌活性的能力。结果表明，家蚕能识别一定的肽聚糖结构，并确定了其最小结构。(2)肽聚糖识别蛋白的分离与鉴定。该蛋白的相对分子质量为37kd，其N末端氨基酸序列与已知的蛋白质没有同源性。结合特异性和其他特性表明，该蛋白最有可能是参与诱导抗菌蛋白基因的肽聚糖识别蛋白。(3)参与…诱导的信号转导系统更多的抗菌蛋白基因。测试各种信号转导抑制剂对肽聚糖诱导抗菌基因的影响，发现二十烷类化合物参与了这些基因的诱导。(4)天蚕素基因启动子的克隆与分析。在这两个基因的启动子区域都发现了一个NF-κB结合基序。通过差异显示的方法，从蓖麻蚕免疫脂肪体的脂肪体中分离到抗菌肽和溶菌酶基因。(6)蓖麻蚕抗菌素基因的分离和克隆。以根据阿特拉星N端氨基酸序列合成的DNA片段为探针，对其进行了克隆和测序。该序列与天蚕蛾的阿特辛有很高的同源性。较少

(1)Minimum structure of peptidoglycan required for the induction of antibacterial proteins.Peptidoglycan fragments which differ in their peptide bridge structure or the chain length were prepared and tested for the inducing ability of antibacterial activity in the silkworm, Bombyx mori. The results indicated the silkworm recognized some definite structure of peptidoglycan, and the minimum structure was determined.(2)Isolation and characterization of peptidoglycan recognition protein.A peptidoglycan binding protein was isolated from immunized hemolymph of the silkworm larvae. The protein had a molecular weight of 37kd, and the N-terminal amino acid sequence so far determined had no homology to known proteins. The binding specificities and other characteristics of the protein showed the protein was the most possible for the candidate of the peptidoglycan recognition protein involved in the induction of antibacterial protein genes.(3)Signal transduction system involved in the induction of … More antibacterial protein genes.Testing various inhibitors of the signal transduction for the effect on the induction of antibacterial genes by peptidoglycan, eicosanoids were found to be involved in the induction of the genes.(4)Cloning and analysis of the promoter of cecropin genes.Two cecropin A gene were cloned by screening the silkworm genome. A NF-κB binding motif was found in the promoter region of the two genes. The protein which specifically bound to the motif was detected only in the nuclear extract from immunized fat body.(5)Detection and cloning of the gene induced by bacterial infection in the Eri-silkworm.By means of differential display method, several bacteria-induced genes including cecropin and lysozyme were isolated from immunized fat body of the Eri-silkworm, Samia cynthia ricini.(6)Protein isolation and cloning of attacin cDNA from Eri-silkworm.Attacin, an antibacterial protein, was isolated from immunized hemolymph of the Eri-silkworm. The DNA fragment synthesized according to the N-terminal amino acid sequence of attacin was used as a probe, and the cDNA was cloned and sequenced. The sequence had high homology to the attacin from cecropia silkmoth. Less