Preliminary Study On The Bioactivity Of The Marine Fungi On Qingdao Coastline

Agricultural plant diseases and pests could lead to a devastating harm to crops.The use of chemical pesticides, which could control plant diseases, had become an important measure to ensure high and stable yields of crops in the world. However, the environmental pollution problem and food safety hazards had occurred, due to the extensive use of chemical pesticides.Most importantly, many agricultural pests would have a change of drug-resistant mutation in the future. Therefore, the problems of the environment-friendly pesticides research should be solved urgently for the agricultural province of Shandong, even the entire country or the world. In this paper, the experiment aimed to obtain marine-derived fungi with antibacterial activity from marine organisms.In the experiment, marine biological samples were collected on Qingdao coastline. A total of 41 strains of marine mold fungi were isolated from samples by the organizational separation,including 24 strains of marine-animal and 18 strains of marine-alga. There was an optimizing process and extraction of 10 strains, which varied in colonial morphology and different sources.In the productivity screening process, we found that the medium of rice had the maximum productivity in the four medium. The TLC tests showed that the metabolites from the nutrient solution were different from those from the fungal mycelium in the same medium of a marine fungus. The different medium could have a effect for active substances in a marine fungus, and05-A strain derived from marine-animal and 21-A strain derived from marine-alga had rich of active substances in the medium rice and MH1, respectively.In the biological activity screening, the experiment of antibacterial activity assay explored the inhibition of four strains of pathogenic bacteria by disc diffusion method. The results showed that 02-A strain showed broad-spectrum antimicrobial activity and had the strong inhibitory effect for Escherichia coli(E.C.), the inhibition zone reached 19mm(positive control for 30mm);21-A strain had a strong inhibitory for Escherichia coli(E.C.), the maximum inhibition zone was up to 23mm(positive control for 30mm). 10 samples had antibacterial effects for Escherichia coli(E.C.) in varying degrees. Meanwhile, the experiment of anti-agriculture pathogenic fungi made qualitative analysis of inhibition for 11 marine fungal by the agar disk diffusion method.The results showed that strains 12-A, 21-A, 24-A, 26-A, 27-A showed a strong fungistasis,among them, 24-A strain could discolor the indicator fungi MHKW and XMQS; 26-A strain lead to the morphological variation of the indicator fungi GJTJ, MHKW, XMQS; 27-A strain had a strong fungistasis against the growth of the indicator fungi.