蚯蚓脂肪及其在抗菌物理屏障中的作用

Earthworm Fat and Its Function as Physical Antibiotic Barrier of Eisenia fetida

以赤子爱胜蚓(Eiseniafetida)为实验动物,采用室内培养方法,研究了细菌浸浴诱导对蚯蚓体内脂肪含量和脂肪酸组成的影响。结果表明:(1)索氏抽提法不能从蚯蚓体腔液中获得脂肪,但是可从蚯蚓的组织中获得脂肪。(2)细菌诱导后,蚯蚓体内的脂肪含量增加0.81%(干物质基础),总脂中的脂肪酸含量均有所增加,其中硬脂酸、油酸、亚油酸增加的幅度较大,分别增加了2.62%,1.58%和1.62%。(3)蚯蚓脂肪的抑菌作用具有选择性,对大肠杆菌的抑菌作用最强,抑菌圈直径为1.32cm;其次为绿脓杆菌,抑菌圈直径为0.97cm,但是对金黄色葡萄球菌没有抑菌作用;大肠杆菌诱导后,蚯蚓脂肪对绿脓杆菌和金黄色葡萄球菌的抑菌作用增强,但是对大肠杆菌的抑制作用减弱。(4)蚯蚓脂肪对大肠杆菌、绿脓杆菌的最低抑菌浓度(MIC)分别为:0.05、0.1g·mL-1;对金黄色葡萄球菌没有抑菌作用。但在细菌诱导后,蚯蚓脂肪对大肠杆菌、绿脓杆菌及金黄色葡萄球菌的最低抑菌浓度(MIC)分别为:0.05、0.1、0.1g·mL-1;(5)蚯蚓的抗菌物理屏障主要是体壁和消化道,而具有抑菌作用的蚯蚓脂肪也主要分布在这些组织中,因此蚯蚓的脂肪代谢在蚯蚓的生态免疫过程中发挥着重要作用。

The experiment was conducted to study the fat and its function in the physical antibiotic barrier of Eisenia fetida. The results showed that： （1） the fat could not be extracted from coelomic fluid of Eisenia fetida by soxhlet extraction method, but the fat could be produced from body of Eisenia fetida by soxhlet extraction method. （2） After the 4-hour inducement of E. coli, the content of fat had the increase of 0. 81% （based on of dry matter）. And the content fall the fatty acid was eased in the inducement. The stearic acid, oleic acid and linoleic acid had an increases of 2.62%, 1.58% and 1.62%, respectively. （3） The antibacterial function of earthworm fat to Escherichia coli was best and bacteriostasis circle has the diameter of 1.32 centimeter. The second was Pseudomonas aeruginosa, and the diameter of bacteriostasis circle was 0.97 centimeter. There was no bacteriostasis influence of earthworm fat on Staphylococcus aureus. So the baeteriostasis selectivity of earthworm fat could be found in the experiment. On the other hand, the bacteriostasis influence of earthworm fat to Pseudomonas aeruginosa and Staphylococcus aureus were increased after the earthworm was induced by E. coli. But the antibacterial function of earthworm fat to Escherichia coli was decreased after the inducement. （4） The MIC of earthworm fat to Escherichia coli and Pseudomonas aeruginosa was 0.05g·mL^-1, 0.1g·mL^-1 respectively. But the MIC of earthworm fat to Staphylococcus aureus could be 0.1g·mL^-1 after the earthworm was induced by E. coli. And there was no change in the MIC of earthworm fat to Escherichia coli and Pseudomonas aeruginosa in the inducement. （5） The main physical antibiotic barrier in the earthworm was the body wall and the digestive system. And the bacteriostasis fat was in these tissues. So the fat metabolism in the earthworm may be playing an important role in the ecology immune system of the earthworm Eisenia fetida.