Objective To study the antibacterial constituents in the fermentation broth of marine actinomyces N331.Methods The antibacterial components were isolated and purified from the fermentation broth of strain N331 by absorption with macroporous resin and silica gel column chromatography,their physiochemical characteristics and bioactivities were preliminarily investigated.Results A crystal ingredient with bioactivities was isolated from the fermentation broth and it was identified as alkaloids which was composed of several compounds with approximate polarity,and its the minimum inhibitory concentration against sensitive and drug-resistant Staphylococcus aureus was 4?g?mL-1,and its half maximal inhibitory concentration(IC50) was 2.0,3.0?g?mL-1 respectively against KB and lung cancer A549 cells,which was equivalent to cisplatin.Conclusion Marine actinomyces N331 can produce the alkaloidal substances with strong antibacterial activity and cytotoxicity.

Objective To study bioactive metabolite produced by marine actinomyces M326.Methods Based on the index of antimicrobial activity,the relation between activity of metabolite and conditions of culture in different media and time were researched,and the stability of bioactive metabolite treated with different temperatures and pH were obseved,and the bioactive ingredients were extracted and separated by organic solvent and by macroporous resin.Results The GBP medium made by artificial seawater or distilled water were suitable for production of strong bioactive metabolites.The antimicrobial substances were stable under pH 2～11 and were heat-resistant under strong acidic condition.It could not be extracted by usual organic solvent,but could be absorbed by AB-8 macroporous resin under alkaline situation.Conclusion The metabolites have strong activity against gram-positive bacteria and have different antimicrobial activities against gram-negative bacteria and drug-resistant strains moreover,the polarity of antimicrobial substances is strong.

Objective To extract and purify a polysaccharide SEP from eggs of sea urchin Strongylocentrotus nudus. and to determine its purity, molecular weight and immunological activity in vitro. Methods The orthogonal design was employed to obtain the best possible combination of the critical parameters for polysaccharide extraction. By ultrafiltration, DE-AE Sepharose Fast Flow anion-exchange chromatography and Sephacryl S-400 gel filtration chromatography, the deproteinated crude polysaccharide was purified. The homogeneity of SEP was proved by HPLC, polyacrylamide gel electrophoresis and paper chromatography. Its molecular weight was determined by HPGPC in reference to standVd T-series Dextran. Lymphocyte proliferation assay was made to investigate the immuno-modulating activity of SEP. Results and Conclusion The results indicated SEP was a homogeneous polysaccharide. Its molecular weight was about 1950KD. SEP increased remarkably spleen lymphocyte proliferation. The homogeneous polysaccharide SEP showed significantly immunological activity in vitro.