The Primary Research Of Antitumor Exopol Ysaccharide Of Marine Bacillus Pumilus PLM4

A strain of Bacillus pumilus PLM4 that can produce ant itumor exopolysaccharide (EPS) had been screened in our laboratory. Studies on isolation, purification, basic structure and antitumoral activity of this EPS were carried out. The main reports were as following:Cells were spun down and discarded by centrifugation from the fermented liquid, then the rude EPS in supernatant were isolated after concentration, dialyse, concentration and precipitated with ethanol. The rude EPS can be purified by Sephadex G-100 column chromatography, this was proved by polyacrylamide gel electrophoresis(PAGE), gel chromatography, and high performance 1iquid chromatography(HPLC).Gas chromatography-Mass spectrometry(GOMS) analysis showed that Mannose and Glucose are involved in this EPS, the molar ratio of them was also determined, mannose:glucose= 3.37:1. Chemical analysis indicated that this EPS involves quite a few hexuronic acids(56. 96%) and few pyruvic acid(0.83%), but without sulfate andacetyl. Molecular weight of this EPS was 116 kDa as determined by HPLC.The primary structure of this EPS has been investigated by using the techniques of infrared spectrometry, periodate oxidation, Smith degradation and GC/MS. The results of these studies indicate that it's a branched molecule possess a backbone of 1→3 linking and side chains of 1→6 linking, with a few 1→2 linking and few 1→4 linking.In the in vitro antitumor activity test of this EPS against Hep-2 cell, strong antitumor activity was observed (GI₅0<15. 6ug/ml). During the in vivo analysis of inhibitory activity of the rude EPS against Sarcoma-180 and H22 growth, it showed distinctly antitumor activity, tumour inhibition ratio of them are 28.70% and 37.72% respectively.