家蝇幼虫壳聚糖的抑菌活性及影响因子

为研究昆虫壳聚糖的抑菌活性及影响因子, 由家蝇Musca domestica幼虫制备了10个不同分子量的壳聚糖，在不同条件下分别对6种细菌作抑菌实验, 并通过测定细菌细胞膜和细胞壁的透性初步探讨了壳聚糖的抑菌机理。结果表明，分子量在21～251 kD的壳聚糖有很强的抑菌活性，抑菌活性呈现随pH的降低而增加的趋势，pH 5.5时最低抑菌浓度在0.03％～0.06%之间，Ca²⁺和Mg²⁺能够显著降低壳聚糖的抑菌作用。通过对实验结果的方差分析表明，壳聚糖的不同分子量、pH值和金属离子等外界因素都是壳聚糖抑菌活性的极显著影响因素，而菌株本身也是极显著影响因素之一。壳聚糖能够增加细胞膜通透性，造成细胞内容物的外泄。

Antibacterial activities of chitosans obtained from cuticle of Musca domestica larvae and affecting factors

In order to study the antibacterial activities of chitosans obtained from cuticle of housefly (Musca domestica) larvae and affecting factors, chitosans with different molecular weights prepared from cuticle of housefly larvae were examined against six bacteria at different conditions. The results showed that chitosans with the molecular weights of 21-251 kD had stronger antibacterial activities. Chitosans showed higher antibacterial activities at low pH value. The minimum inhibitory concentration of chitosans ranged from 0.03%-0.06%. Ca 2 and Mg 2 could reduce the antibacterial activity of chitosans remarkably. Molecular weight of chitosans, pH value and ion were the factors strongly affecting the antibacterial activities of chitosan, which was also significantly related to the strain of the bacteria. Chitosan could increase cell membrane penetrability of the bacteria and cause the leakage of cytoplasm.