[Identification and Fermentation Optimization of an Endophytic Fungus BLH34 with Antibacterial Activity from Macleaya cordata].

Objective: To identify an endophytic fungus BLH34 isolated from the leaf of Macleaya cordata with antibacterial activity,and to optimize its fermentation medium. Methods: Antimicrobial activity of an endophytic fungus BLH34 was determined by the cylinder plate method. The morphological characteristics and internal transcribed spacer（ ITS） sequence were analyzed to identify the taxonomic position of the strain BLH34. The culture medium recipe was optimized by single factor and orthogonal experiment. Results: The results showed that the strain BLH34 had antimicrobial activity to the test strains,especially it showed significant inhibitory effect on Staphylococcus aureus. The strain BLH34 was identified as Penicillium turbatum,and the best culture medium recipe could be recognized as follows: 5% soluble starch,4% peptone,0. 06% NaNO3,and 0. 012% MgSO4·7H2O. Conclusion: The antimicrobial activity of crude extract was significantly increased after optimization, which could provide a basis for further separation and purification of the antibacterial substances extracted from strain BLH34.

[Isolation and antimicrobial activities of actinomycetes from vermicompost].

In this paper, actinomycetes were isolated from vermicompost by tablet coating method. Antimicrobial activities of actinomycetes were measured by the agar block method. Strains with high activity were identified based on morphology and biochemical characteristics, as well as 16S rDNA gene sequence analysis. The results showed that 26 strains of actinomycetes were isolated, 16 of them had antimicrobial activities to the test strains which accounts for 61.54% of all strains. Among the 16 strains, the strain QYF12 and QYF22 had higher antimicrobial activity to Micrococcus luteus, with a formed inhibition zone of 27 mm and 31 mm, respectively. While the strain QYF26 had higher antimicrobial activity to Bacillus subtilis, and the inhibition zone diameter was 21 mm. Based on the identification of strains with high activity, the strain QYF12 was identified as Streptomyces chartreusis, the strain QYF22 was S. ossamyceticus and the strain QYF26 was S. gancidicus. This study provided a theoretical basis for further separate antibacterial product used for biological control.

[Isolation of Actinomycete DF02 from Composting and Its Application in Biological Control of Botrytis cinerea].

OBJECTIVE: To isolate and identify the biocontrol actinomycete from composting, and to investigate its potted control effect against Botrytis cinerea. METHODS: Actinomycetes were isolated from composting by pour plate method. Inhibitory activities of acti- nomycetes were determined by dilution plate method and cylinder plate method. Strain with high activities was identified based on mor- phology and biochemical characterization and 16S rDNA gene sequence analysis. And its potted control effect was also investigated. RESULTS: 31 strains of actinomycetes were isolated, three of them had inhibitory effects on the test strains. Of which, the strain DF02 showed antagonistic to five plant pathogenic fungi of all the tested strains, and its inhibitory effect on Botrytis cinerea was the strongest. The results of potted control effect test showed that the protective and therapeutic efficacy of the fermentation suspension to Botrytis cinerea was 58.47% and 53.83%, respectively. According to taxonomic identification, the strain DF02 was identified as Strepto- myces neopeptinius. CONCLUSION: Strain DF02 is a biocontrol actinomycete with broad development potential, and these results provide ex- perimental basis for the biocontrol of Botrytis cinerea.

An endophytic sanguinarine-producing fungus from Macleaya cordata, Fusarium proliferatum BLH51.

Fermentation processes using sanguinarine-producing fungi other than Macleaya cordata may be an alternative way to produce sanguinarine (SA), which is a quaternary benzo[c]phenanthridine alkaloid possessing antibacterial, anthelmintic, and anti-inflammatory properties. In this study, a SA-producing endophytic fungus strain BLH51 was isolated from the leaves of M. cordata grown in the Dabie Mountain, China. Strain BLH51 produced SA when grown in potato dextrose liquid medium. The amount of SA produced by this endophytic fungus was quantified to be 178 µg/L by HPLC, substantially lower than that produced by the host tissue. The fungal SA--which was analyzed by thin layer chromatography and high-performance liquid chromatography--was shown to be identical to authentic SA. Strain BLH51 was identified as Fusarium proliferatum based on the morphological characteristics and nuclear ribosomal DNA ITS sequence analysis. To the best of our knowledge, this is the first report concerning the isolation and identification of endophytic SA-producing fungi from the host plant, which further proved that endophytic fungi are valuable reservoirs of bioactive compounds.

[Isolation and identification of an antimicrobial endophytic actinomycete from Macleaya cordata].

OBJECTIVE: An antimicrobial endophytic actinomycete strain was isolated from the root of Macleaya cordata, and its phylogenetic position was also investigated. METHODS: Endophytic actinomycetes were isolated from the root of Macleaya cordata growing in Dabie Mountain by tablet coating method. Antimicrobial activities of endophytic actinomycetes were determined by the agar block method,and then a potential strain was identified by morphology, biochemical characterization and molecular methods. RESULTS: A total of 15 strains of endophytic actinomycetes were isolated from the samples, six of them had antimicrobial activity to the test strains which accounts for 40% of all strains. Among the six strains,the strain BL7 was found to produce antibiotic substances which showed significant inhibitory effects on Staphylococcus aureus and Bacillus subtilis,with a formed inhibition zone of 29 mm and 20 mm respectively. Based on the morphology, biochemical characterization and 16S rDNA sequence analysis,the strain BL7 was preliminary identified as Streptomyces mobaraensis. CONCLUSION: Some members of Streptomyces genus have a very wide application prospect in medicine. This is the first report that Streptomyces mobaraensis strain was isolated from Macleaya cordata, and this study provides basis for the further exploration of the strain.