| Endophytes,has become an important component of the microorganism resources.Undoubtedly it has the enormous application value,and it plays a very important role in drug research and development of natural pigment.In this paper,some common plants of Guangxi Zhuang Autonomous region were chose as the research object,more than 20 species of plants were collected from Nanning Liang-Feng-Jiang National Forest Park,and all the plant's root,stem and leaf tissue block were as the experimental materials for the separation and purification of endophyte.59 strains entophytic bacteria and 145 strains entophytic fungi were isolated from roots,stems and leaves of more than 20 species plant.Among the 59 entophytic bacteria strains showing antibacterial activity,at least 11 strains were found antagonistic activity upon an indicator bacteria,6 strains had antagonistic activity upon two kinds of indicator bacteria.The methanol crude extracts of 5 strains entophytic fungi fermentation supernatant fluid has bacteriostatic action on at least one indicator bacteria.The fermentation broth of entophytic bacteria SM-8 isolated from Chinese fir showed strong inhibitory activity against Escherichia Coli and Staphylococcus aurous in antibacterial activity screening experiment.The fermentation broth of entophytic fungi Y-74 isolated from Burmann Cinnamon Bark showed greater antibacterial activity against Staphylococcus aureus and Bacillus subtilis.At the same time,one endophyte in the isolated endophytes was found to can produce natural red pigment,named as entophytic fungi T-28,these three stains were investigated in the subsequent work.Firstly,the endogenous bacterium SM-8 was identified and its fermentation condition was optimized.Culture characteristics and some physiological biochemical characteristics of the endogenous bacteria SM-8 had investigated,at the same time the molecular identification of the strain using 16S rDNA sequencing technology was completed.The results showed the endogenous bacteria SM-8 is Bacillus subtilis,named as Bacillus subtilis SM-8.And the 16S rDNA sequences of Bacillus subtilis SM-8 already was submitted to GenBank(Accession number KC257097).The optimal carbon source is sucrose and the optimal nitrogen source is peptone,the optimal pH value is 6.0.Endogenous bacteria SM-8 can growth when the pH value range 4.5 to 9.0.Optimum temperature is 30?,it can grow in 15? to 55? temperature range.The growth characteristics and morphological observation of entophytic fungi Y-74 was investigated,and the molecular identification of strains was completed using ITS-rDNA sequencing technology.Results showed that the entophytic fungi belong to Penicillium citrinum.By the nucleotide homology analysis,the homology of Y-74 is 100%with Penicillium citrinum JQ717340,JQ712839,FJ765031,GU565103.After separation and purification of fermentation broth of the strain Y-74,11 components were obtained.The second,fourth and fifth,sixth components showed certain antibacterial activity through bacteriostatic experiment.And the components were analyzed using GC-MS.One pure substance was been isolated from the second component,but it is a pity that the substance is not showed antimicrobial activity.At the same time,the corresponding research was carried out to the stain T-28.First of all,the physiological and biochemical characteristic of strain T-28 was investigated,and the stain have been identification by the mean of molecular biology.Results showed the strain belongs to Fusarium lateritium,and its sequence has been submitted to GenBank(Accession number KC787693).The fermented liquid of stain T-28 was been separated and purified by using silica gel column chromatography,and ethyl acetate as eluent.The components of pigment were analyzed by GC-MS.Analysis shows that the red pigment is mainly composed of three kinds of substance.But due to the lack of characterization data,the structure of three kind's substance is still not clear. |
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