柞蚕杀菌肽对桉树青枯病假单胞菌的杀菌作用

THE BACTERICIDAL EFFECT OF ANTIBACTERIAL PEPTIDE FROM CHINESE OAK SILKWORM,Antheraea pernyi ON THE BACTERIAL WILT OF EUCALYPTUS

桉树、木麻黄青枯病是广东省林业主要病害，近年为害猖獗导致严重损失。本文报道柞蚕杀菌肽Ｄ对桉树、木麻黄青枯病假单胞菌（Ｐｓｅｕｄｏｍｏｎａｓｓｏｌａｎａｃｅａｒｕｍ）的杀菌作用。以荧光黄染料隅联的杀菌肽作用于青枯病假单胞菌，用电镜及激光共焦扫描显微镜观察，发现杀菌肽能迅速地将菌体包围、作用于细胞膜，造成许多小孔并进入胞内，尔后损伤的小孔扩大形成喇叭口，内含物由此泄出胞外，最后菌体变成空囊而死亡。

The bacterial wilt(Pseudomonas solanacearum)of eucalyptus(Eucalyptus tereticornis)and equisetum(Casuarina equisetifolia)are important diseases in South China. This paper reports the bactericidal effect of antibacterial peptide from the Chinese oak silkworm(Antheraea pernyi)on the pathogens of bacterial wilt of eucalyptus and equisetum. Antibacterial peptide was induced in Chinese oak silkworm pupae by injecting Escherichia coli K12D31.Antibacterial peptide was purified from the haemo-lymph with CM-Sepharose CL-B6 and phenyl sepharose 4B. The purified antibacterial peptide had a molecular mass of a substanee of 4000 u and was labelled with fluo-rescent yellow. The pathogens wers treated with 10 mg/L of antibacterial peptide and observed under the scanning electron microscopy and laser scanning confocal imaging system to study how the antibacterial peptide inhibited and killed the bacteria.The result showed that the primary taget was the cell membrane. the fluorescent substances aggregated surrounded and embraced the surface of the bacterial membrane.then permeated into the cell and distroyed the membrane. Some small channels were found on the surface of the cell, the intracellular substances were forced out of the cell and finally the cell became empty and died.