Screening Of Marine Microbes With Antitumor Activity And Study Of The Active Compounds Produced By Strain B2817

It is well known that tumors have been a severe threat to human health for a long time. Medication is the main treatment of tumors. There are about 50 kinds of drugs often used in clinic, most of them can only alleviate the state of illness but can't cure it completely. So it is very important for us to develop new antitumor drugs. Halobios account for 80% of the creatures on the Earth and they have abundant metabolic pathways. They can produce large amounts of metabolites with novel structure and excellent bioactivity. Marine microbe is an important new source for antitumor drugs and is deserved more attention to be exploited because they are easy to be collected and be reproduced in large scale in industry.In order to find antitumor microbes, first we established Fusarium model and validated its applicability by using antitumor drugs. Results showed that the model was suitable to screen active antitumor substance. Combining Fusarium model and cytotoxicity model, we got combinatorial screening model for antitumor substance. The combinatorial model was applied to screen marine actinomycetes and the results showed that the model was proper to process large amount of samples quickly with low omitting rate.From 75 samples, 2042 strains of different microbes were isolated including 1269 strains of bacteria, 395 strains of actinomycetes and 378 strains of fungi. Of all the isolates, there were 242 strains with antitumor activity (ID₅₀ > 50), including 136 strains of bacteria, 83 strains of actinomycetes and 23 strains of fungi. And among the 242 strains, there were 76 strains which ID₅₀ were above 200 and they had genetic stability to produce active substance.Strain B2817 is a bacterial strain which fermentation broth exhibites selective inhibitory activity against tumor cells. And its ID₅₀ on human liver cells SMMC-7721, rat sarcoma cell cells S180 and human rhinopharyngocele cells were all above 1000, while no inhibitory activity was detected against human liver cells L-02.Numerical analysis indicated that strain B2817 was a species of genus Vibrio and shared high homologies with Vibrio rubber and Vibrio gazogenes. The 16S rDNA...