Mutagenesis Of Endophytic Fungi From Curcuma Wenyujin By The Simulating Space Environment And Studies On The Bioactivity Of Its Metabolites

Objective:Endophytic fungus EZG0807 isolated from Curcuma wenyujin was mutagenized through the simulating space environment of micro-gravity and high magnetic field, aiming to screen the mutant strain with higher bioactivity. And it was compared with the starting strain EZG0807 at the aspect of cell growth, morphology and bioactivity of its metabolites.Methods:The mutant strains were screened by the microdiluted method. To screen the active mutant, filter paper method and MTT assay were utilized to investigate its metabolites activity against the test bacteria Staphylococcus aureus, Proteus vulgaris, Escherichia coli, Bacillus subtilis and tumour MCF-7, respectively. The screened mutant was then compared with the starting strain EZG0807 at the aspect of morphology through observing the morphology of the colony, mycelium and spores with visual and microscope. Using cross method to measure the colony diameter on PDA medium and dry weight method to determine the growth curve in Czapek Dox medium to contrast the growth rate between the two strains. The antibacterial and antitumor activity of metabolites of the two strains was contrasted by filter paper method and MTT assay.Results:1.129 strains were isolated from the endophytic fungus EZG0807 from Curcuma wenyujin treated by the simulating space environment. Among these,15 strains were get under the condition of 24 h,0 g; 24 h,1 g 14; 24 h,2 g 16; 48 h,0 g 17; 48 h,1 g 6; 48 h,2 g 22; 72 h,0 g13;72h, 1g14and72h,2g12;2. The result of the initial screening by filter paper method showed that the metabolites of 17 strains among the 129 strains had good inhibition effect to Staphylococcus aureus, Proteus vulgaris, Escherichia coli and Bacillus subtilis;3. The result of the secondary screening by MTT assay manifested that the inhibition rate of metabolites of the mutant 72 2-6 to MCF-7 cells was 58.08% higher than the starting strain EZG0807;4. At the aspect of the colony morphology, the mycelium of mutant 72 2-6 was upright shape, slender and more bulking than strain EZG0807, the substrate color was dimmer; the morphology of mycelium and spores of the two strains were almost the same, but sporangia were found in the strain EZG0807 only; 5. Finding by comparing the colony diameter and growth curve, the growth rate of mutant 72 2-6 was slower than strain EZG0807 on PDA medium, also in Czapek Dox medium, but the dry weight of cell of the two strains after stabilization period was almost the same;6. At the aspect of bioactivity, the inhibition of metabolites of mutant 72 2-6 was almost the same with the starting strain EZG0807 to Proteus vulgaris, and lower than it to the other three instructed bacteria. But to the inhibition to MCF-7 cells, it was higher than the strain EZG0807.