Molecular Mechanisms of Self-defense system in Insect

1.蓖麻蚕（Samia cynthia ricini）细菌诱导基因的cDNA克隆与表达利用差减杂交技术，分离到了几个细菌诱导基因的cDNA片段。以这些DNA片段为探针，从免疫后的Samia脂肪体cDNA文库中筛选出编码Hdd 11（一种功能未知蛋白）、新的lebocin样蛋白、酪氨酸3-羟化酶和两种丝氨酸蛋白酶的全长cDNA，并进行了序列测定。3.家蚕和蓖麻蚕肽聚糖结合蛋白的分离、鉴定及PGRP的cDNA克隆利用光亲和标记技术，从家蚕和蓖麻蚕血淋巴中分离并鉴定了肽聚糖（PGN）结合蛋白<125>、PGRP和其它三种蛋白。从免疫的蓖麻脂肪体中克隆了两个PGRP cDNA，其中一个编码分离的PGRP蛋白。另一个PGRP cDNA与果蝇的PGRP LB有很高的同源性，并且在中肠中有很强的诱导作用。

1.cDNA cloning and expression of bacteria-induced genes in the Eri-silkworm, Samia cynthia riciniWith use of subtractive hybridization method, several cDNA 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, full length cDNAs encoding Hdd11 (a function unknown protein), novel lebocin-like protein, tyrosine 3-hydroxylase, two serine proteases have been cloned and sequenced. All of these genes were strongly induced by an injection of bacterial cells or peptidoglycan.3.Isolation and characterization of peptidoglycan-binding proteins from Bombyx mori and S.ricini, and cDNA cloning of PGRPDetecting peptidoglycan (PGN) binding activity by means of photo affinity labeling with ^<125>I-PGN, a PGRP and three other proteins were isolated and characterized from the hemolymph of B.mori and S.ricini. Two PGRP cDNAs were cloned from the fat body of immunized S.ricini, one of which coded the isolated PGRP protein. The other PGRP cDNA had significant homology with PGRP-LB of Drosophila, and strongly induced in midgut.