| The microbes survive in extreme situations have become a hot spot and trend of the development of new drugs in recent years because of their specific gene type,physiological function and structure of the novel metabolites.But most tend to medical research,few reports of pesticide research.Based on the above researches,we will isolate and screen of the symbiotic and epiphyte microorganisms from marine bryozoans Bugula neritina with insecticidal activity and use the method of TLC in order to gain substance rich strains.And then identificate of the active strains.Main results are as follows.(1)91 symbiotic and epiphyte microorganisms were separated from marine bryozoans Bugula neritina,61 strains of bacretia,25 strains of fungi and 5 strains of actinomycetes.According to the preliminary morphological identification,the bacteria containes Pseudomonas(16 strains)、Vibrio(13 strains)、Pseudoalteromonas(10 strains)、Bacillus(1 strain)、Sphingomonas(4 strains)、Shewanella(4 strains)、Alteromona(6 strains)and Flavobacterium(7 strains);the fungi containes Penicillium(9 strains)、Aspcrgillus(14 strains)、Trichoderma(2 strains);and the actinomycetes containes all Streptomyces(5 strains).Based on the above analysises,the main symbiotic and epiphyte microorganisms is bacteria(67%),then the fungi(28%).Statistics on the species the results show that the main genuses of bacteria are Pseudomonas,Vibrio and Pseudoalteromonas;the main genuses of fungi are Penicillium and Aspcrgillus;and the main genus of actinomycetes is Streptomyces.(2)The insecticidal activity against Artemia of 91 symbiotic and epiphyte microorganisms was determinated.The results showed that the mortality more than70%after 24h against Artemia were 26 strains,28.57%of the total strain.Bacteria,fungi and actinomycetes were 6,17 and 3 strains,accounting for 23.08%,65.38%and 11.54%of the number of the total active strains respectively.Among them,the fermentation of strain B-Z-10-23,B-Z-10-35,B-Z-37,and B-Z-12-17could kill all the Artemias within 30 minutes.And the fermentation of strain B-X-4-8,B-X-4-14,B-F-10-41 and B-Z-5-31could kill all the Artemias within 3 hours.Analysing the distribution of 26 active strains,we could see the Penicillium and Aspcrgillus were the main genuses.(3)The insecticidal activity against Plutella xylostella and Tetranychina harti of 26 active strains was determinated.The results showed that 8 strains had some poisonous activity to Plutella xylostella.Among them the mortality more than 70%after 72h against Plutella xylostella were 3 strains,they were B-Z-5-31,B-Z-10-35 and B-Z-12-17.14 strains had some antifeedant activity to Plutella xylostella.Among them the antifeeding rate more than 70%after 24h against Plutella xylostella were 2 strains,they were B-X-4-8 and B-X-4-14,then were strain B-Z-5-14,B-Z-5-31,B-Z-10-35 and B-F-10-41(>30%).21 strains had some poisonous activity to Tetranychina harti.Among them the mortality more than 60%after 24h against Tetranychina harti were 4 strains,they were B-X-12-100,B-X-10-169,B-Z-12-17 and B-F-10-41,then were the strains B-X-4-8,B-Z-10-23,B-Z-9-26,B-Z-10-35 and B-F-7-37(>40%).(4)The substances diversity about 7 active strains were determinated.The results showde that strain B-Z-5-31 and B-Z-12-17 showed significant material and structural diversity.Based on the above researches,the insecticidal activity of strain B-Z-5-31 and B-Z-12-17 of their extracellular metabolites crude extracts against Plutella xylostella and Tetranychina harti were determinated.The results showde that the LC50 of the extracellulalr metabolites crude extracts of B-Z-5-31 and B-Z-12-17 against Plutella xylostella were 50.197 mg/mL,4.609 mg/mL respectively.And the LC50 of the extracellularmetabolites crude extracts of B-Z-12-17 against Tetranychina harti were 36.281 mg/mL.(5)Basing on the morphological and molecular characteristics,B-Z-5-31 and B-Z-12-17 were preliminarily identified as Aspergillus versicolor and Penicillium polonicum. |
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