| As a big group of microbe inhabiting in the living tissues of plants, endophytes have no negative effects on the host plants during their whole life history or some phases. Because of their particularity of living environment, endophytes are different from the environal microorganisms on biological function and physiology. During the long run road of the evolution, a symbiosis system has formed between endophyte and host, the change of environment conditions and host metabolisms affect the change of genus and metabolism in endophytes correspondingly. Along with an increase in the number of people in the world having health problems caused by certain cancers, drug-resistant bacteria, parasitic protozoans, and fungi have caused alarm. An intensive search for newer and more effective agents to deal with these problems is now underway. Endophytes are a potential source of novel chemistry and biology to assist in helping solve not only human health, but plant and animal health problems also. Now we are just at the beginning of the researching on endophytes, we can not take full advantages of endophytes because many of their characters have not been understood, so research on the anti-microbe endophytes not only brings vast social profits but also has realistic theoretic significance. In this scientific dissertation, some medicinal plant tissues were chosen as the materials for separation of antimicrobial endophytes, A11, one of produced wide-spectrum antibacterials endophytes isolated from Aloe, was indentified by physiological and biochemical techniques, and the antimicroorganism substances were purified. The results were as follows.1. By tissue surface-sterilized, about 115 strains endophytes isolated from the tissues of ginkgo, aloe etc. Of these 115 isolates, there were 60 endophytic bacteria and 55 endophytic fungi, incubated at 28℃ for two weeks, most of those fungi were not producing spores. Amongst 115 isolates we have screened 5 endophytes which have different antibacterial activities, they were G6, A11 ,F4,N11, N20. G6, one endophytic fungus isolated from the foliage of Ginkgo biloba L. All, one endophytic bacterium isolated from the foliage of Aloe Chinensis (Haw.)Baker. F4, one endophytic bacterium isolated from the vine of Ficus tikona Bur. Nl land N20, two fungi isolated from the bark of Neriumindicum CV. Paihua. we chose All to lucubrate just because of its wide-spectrum antibacterial activity.2. By antimicroorganism assay, wide-spectrum antibiotics produced by isolate All were strong effects against the gram-positive bacteria such as staphylococcus aureus &bacillus subtilis etc but little anti-effect to the gram-negative bacteria, and were good effects against the phytopathogen such as Phytophthora infestans, Trichothecium Link, Gloeosporium laeticolor Berkz etc, and also against the mildew such as Pencollium spp. Aspergillus flaws etc, which cause foodstuff decayed. Isolate All grew well in the culture medium with initial pH 4-10, the optimal growth temperature range was from 28 to 30.5 degree C. It grew well on the medium for fungi growth, such as PDA medium and czpek medium etc, and also grew well on the Cause's I medium and the non-nitrogen medium, but little growth on the Luria Bertani medium(LB) and beef extract peptone medium.It did not need special nutrition factors for growth, but source of the carbon was the key factor to growth, all of its nutrition needs were different from that of common bacteria. Incubated in a carbon source richness culture medium, A11 produced large of viscidity compounds as well as aloe, further research is needed to determine whether there were necessity contacts or the results of choice each other between isolate A11 and aloe.3. Refer to 8th Edition of Bergey' s Manual of Determiminative Bacteriology and Manual of common Determiminative Systematic bacteriology, Gram staining, motility, production of catalase and oxydase etc were assayed. The results as follow: thalli shape of strain All was bacilliform, bacterial spore was bulged at center or near...
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