论文部分内容阅读
This study investigates the antibacterial effects of the endophtic fungi producing naringenin and the mechanism on Staphylococcus aureus.A fungal endophyte P5 with obvious antibacterial activities was isolated from Dalbergiae and identified as Aspergillus fumigatus by ITS sequence.By double broth dilution method,the minimum inhibition concentration(MIC)and minimum bactericidal concentration(MBC)value were measured by 96-well plate method.Results showed that the MIC value of Staphylococcus aureus with endphyte extracts containing naringenin was 10 μg/mL and MBC value was 20μg/mL.Through the crystal violet and DNA permeability experiments,the change of cell membrane integrity was determined.With the increase of naringenin concentration,crystal violet and DNA permeability experiments absorbance increased,the results showed that cell membrane integrity was damaged.Scanning electron microscopic observations of the morphologies of S.aureus treated with fungal extracts further confirmed that endophyte extracts with naringenin can damage the cell membrane and membrane integrity,which may eventually induce growth inhibition and bacterial death.