Molecular Mechanisms of Self-defense system in Insect

1. 蚕、蓖麻幼虫细菌诱导基因的筛选通过差异克隆的方法比较幼虫和注菌幼虫脂肪体中的mRNA，分离出12条针对注菌幼虫特异的DNA片段。 2.溶菌酶和attacin的分离和表征从免疫蓖麻毒素血淋巴中分离得到一种溶菌酶，其N端氨基酸序列与cDNA推导的氨基酸序列完全匹配。将该酶的性质与其他鳞翅目溶菌酶进行了比较。对一种attacin进行了类似的分离和表征。 3.家蚕和蓖麻毒素肽聚糖结合蛋白的分离和鉴定。通过^125I-PGN光亲和标记检测肽聚糖（PGN）结合活性，从家蚕血淋巴中分离和鉴定了三种与PGRP不同的蛋白质。其中一种蛋白质（31kd）是血淋巴蛋白（C-19）已被分离并测序，但其生理作用尚不清楚。该蛋白不仅与PGN结合，还与寡聚几丁质和LPS结合。第二种蛋白是促进蛋白，它是由于刺激核多角体病毒复制而分离出来的。从免疫萨米亚幼虫的血淋巴中分离到两个PGRP。

1. Screening of bacteria-induced genes in Eri-silkworm, Samia cynthia riciniComparing mRNAs in the fat bodies from naive and bacteria-injected larvae by means differential cloning method,12 DNA fragments,which were specific for bacteria-injected larvae,were isolated.After screened a cDNA library of immunized Samia fat body with these DNA fragments as probes,cDNAs for a lysozyme,three attacins and two peptidoglycan recognition proteins(PGRP)have been cloned and sequenced.2.Isolation and characterization of lysozyme and attacin.A lysozyme was isolated from immunized hemolymph of S.ricini.The N-terminal amino acid sequence was in perfect match of that deduced from the cDNA.The properties of the enzyme was compared with other lepidopteran lysozyme.An attacin was similarly isolated and characterized.The attacin was bactericidal only to Gram-negatives.3.Isolation and characterization of peptidoglycan-binding proteins from Bombyx mori and S.ricini.Detecting peptidoglycan (PGN) binding activity by means of photo affinity labeling with ^<125>I-PGN,three proteins,which were different from PGRP,were isolated and characterized from the hemolymph of B.mori.One of the proteins (31kd) was the hemolymph protein (C-19),which had been isolated and sequenced,but whose physiological role was not known.The protein binds not only to PGN but oligo chitin and LPS. The second protein was promoting protein,which had been isolated as the protein stimulated replication of nucleopolyhedrovirus.Two PGRP were isolated from immunized hemolymph of Samia larvae.