Study On The Agricultural Antibiotics Of Symbiotic Or Epiphytic Actinomycetes From Marine Animals And Plants

In this work, a model, which involved Brine shrimp(Artemia salind) and double layer agar diffusion method, is established for prescreening insecticidal antibiotics. Utilizing this model, a total of 149 antinomycetes colonies, isolated from marine animals and plants which collected from the intertidal zone of xiamen coast, Taiwan strait, were tested. Additional, these strains were also screened for fungicidal antibiotics, utilizing double layer agar diffusion method, Fusarium sp., Curvularia sp. etc. as indicator. This work tries to set forth the influencing degree of marine animals and plants to the distribution of insecticidal and fungicidal source from symbiotic or epiphytic actinomycetes. The physiological and biochemical characteristics of the high activity strains were studied.The result shows that the source of insecticidal and fungicidal activity strains in the symbiotic or epiphytic actinomycetes from marine animals and plants are abundant. 22.1 percent of the 149 strains have insecticidal activity, and 12.8 percent of the 149 strains have fungicidal activity. The actinomycetes from Caloglossa leprieurii, Caremu lariahaberei, Hypnea sp. and Ulva lactuca L. have the high ratio of insecticidal activity strains, above 30 percent, the ratio of fungicidal activity strains from Caloglossa leprieurii even reaches about 40.90 percent. The distribution of high activity strains is due to the difference of host. Caremu lariahaberei has the highest ratio of high insecticidal activity strains among the 8 species of marine animals and plants, about 30%, and Caloglossa leprieurii is the following, about 27.3 percent. The high fungicidal activity strains are distributed in Caloglossa leprieurii, Caremu lariahaberei, Hypnea sp. , the three marine organisms account for about 8.6 percent of all the 149 strains, and Caloglossa leprieurii has the highest ratio of high fungicidal activity strains, 31.8 percent of all strains from itself are high fungicidal activity. It demonstrates that different insecticidal and fungicidal source are distribution in different host. The remarkable influencing to the distribution of high insecticidal and fungicidal activitystrains comes from host. The insecticidal and fungicidal source of symbiotic or epiphytic actinomycetes from Caremu lariahaberei and Caloglossa leprieurii have a good value in the further research and development.Strain of 2934 and 449 has high insecticidal and fungicidal activity. They are identified as species of the genus Streptomyces. The ID50 to Brine shrimp of fermentation broths of 2934 is above 100, to Rhabditis sp. and Meloidodera sp. is above 20, The fermentation broths have middle activity to Aphis sp. and Tetranychus sp.. The activity substance of 2934 is fat-soluble, one of the fractions(Rf=0.31 on developed thin-layer plate, solvent system: CH3Cl-MeOH (96:4)) has insecticidal activity. 449 has strong fungicidal activity to soil-transmitted pathogenic microorganisms, such as Fusarium sp., its Di/Dc are above 4.0, and the antimicrobial spectrum is wide. The activity substance of 449 is fat-soluble, too. Two of the fractions(Rf=0.21,0.31 on developed thin-layer plate, solvent system: CH3Cl-MeOH-HAc(98:l:1.5)) has fungicidal activity. They will be value of potential application.