| The effects of antibiotic barrier (physical and mucilaginous elimination) and joint prevention in the antibacterial immunity system of Eisenia fetida were analyzed in this study by applying animal immunology, ecology and biochemistry. The main results of this study were as the followings.The first part of this study researched the influence of bacterium inducement on the ultrastructure integumentary system in Eisenia fetida. Antibacterial function of body wall was conducted by the following way: microorganism was directly resisted through the change of cuticle, such as incrassation of up-cuticle protuberance and increasing length of micro-floccus in the up-cuticle dissociation surface; exudation function of large granular orthochromatic mucous cells and reticulation mucous cells in the epidermis could be enhanced when the Eisenia fetida was induced by E. coli. Moreover, the mucus that contained compound substance of mucopolysaccharide and protein could make the bactericidal function or dilute the microorganism on the surface of earthworm, which could protect earthworm from invasion of microorganism; the content of neutral mucopolysaccharide of antibacterial function could be increased according with the exudation increment of small granular proteinaceous cells in the epidermis, which could resist bacteria invading into the epidermis of earthworm.The second part of this study researched the function of skin secretions in the antibacterial immunity ecosystem of Eisenia Foetida. It was shown: the antibacterial function of earthworm skin secretions to Staphylococcus aureus was the best and the diameter of bacteriostasis circle was 1.22 centimeter. Those to Escherichia coli and Pseudomonas aeruginosa were 1.13 centimeter and 0.98 centimeter respectively. After the earthworm was induced by Escherichia coli, the bacteriostasis influence of earthworm skin secretions to Escherichia coli and Staphylococcus aureus were increased significantly (P<0.01). But the antibacterial function to Pseudomonas aeruginosa was not increased; Earthworm Slime Peptide (ESP) was purified from body surface slime of Eisenia Foetida by gel filtration using Sephadex G-75 and G-50 connected with G-25. And ESP-1 was achieved from ESP by C-18 reversed-phase High Performance Liquid Chromatography (HPLC) techniques. It was also found that the ESP-1 was composed by 50 residues of sixteen different amino acids, among which ten residues was serine. And molecular weight of ESP-1 was 5814.32 D, which was determined by Matrix Assisted Laser Desorption Ionization (MALDl) and Time Of Flight Mass Spectrometry (TOF/MS). The minimum inhibitory concentrations (MIC) of ESP-1 to Pseudomonas aeruginosa and Staphylococcus aureus were 6.25mg/mL, 12.5mg/mL and 50mg/mL respectively. The crude agglutinin was also isolated from earthworm skin secretions. After the earthworm was induced by Escherichia coli, the content of indicans of this agglutinin was increased from 1.66 + 0.16% to 3.75 + 0.13%. And antibacterial activities of the agglutinin to Escherichia coli and Staphylococcus aureus were also increased, but bacteriolytic activities of the agglutinin were decreased.The third part of this study researched fat and its function in the physical antibiotic barrier ofearthworm. It was shown that the antibacterial function of earthworm fat to Escherichia coli was the best and the diameter of bacteriostasis circle was1.32 centimeter. That to Pseudomonas aeruginosa was 0.97 centimeter. There was no bacteriostasis influence of earthworm fat on Staphylococcus aureus. The antibacterial activities of earthworm fat to Pseudomonas aeruginosa and Staphylococcus aureus were increased after earthworms were induced by Escherichia coli. But that to Escherichia coli was decreased after the inducement.The fourth part of this study researched the polysaccharides and its function in the physical antibiotic barrier of earthworm. Mucopolysaccharides that had broad antibacterial activities was isolated from both earthworms and induced earthworms. Both of mucopolysaccharides were composed by five mole...
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