| Marine planktonic diatom(MPD), one of the monocellular planktonic population of marine microalgae, becomes more and more widely used in marine aquiculture and marine bio-pharmacy, as it contains rich extracellular and intracellular substances such as polysaccharides and polyunsaturated fatty acids(PUFA). In this paper, the study were conducted on isolation and preservation of the species of MPD, the massively optimizing cultivation, increasing production and harvest of MPD, and the extraction, isolation, purification, analysis of the components, furthermore on modification of the structure of extracellular and intracellular substances and their pharmacological activities. The results are summarized as follows: 1. The species of MPD can be selected by dilution and micro-picking, and the purpose and efficiency of separating target-algaes in the method of micro-picking is greater than that in dilution. The differences of preserving conditions among the various the species of MPD are significant. The microalgae Nitzschia closterium could grow well without being polluted and it was not need to exchange the culture media for more than 60 days in this qualification, which was conserved in optimizing media with inoculating concentration of 3×10~5 cells/ml, pH value of 7.5-8.5, water temperature of 4℃, no lighting, protection of bi-antibiotic and the consistency of —the growth affection factor(GAF) of MPD—at 800mg/L whereas Phaeodactylum tricornutum was preserved with water temperature of 25℃, photoperiod of 10﹕14. 2. It can be massively cultivated for MPD in the special optimum media. Being added in, GAF was of great efficiency for Phaeodactylum tricornutum to increase production, to accelerate growing and to prevent from being polluted by of accompanying algae when the consistency of GAF was at 800mg/L, whereas the effect on Nitzschia closterium arrived at the highest value when GAF was at consistency of 1000mg/L. The bodies of MPD could be gathered by flocculating and low-speed centrifuging which is much more convenient, compared with the method of flocculating. It could be concluded that the influences of GAF to the growth rate of the two species of diatom was notably significant. GAF may be used not only as promoting element to marine pelagic diatoms, but also as restricted one to accompanying algaes. It is a brilliant innovation that the target microalgae was purified and speeded up while the growing of accompanying microalgae was restrained, which antipollution ability and adaptability were boosted up when it was breeded in large scale. 3. The extracellular substance, which was acquired by filtration, concentration in low temperature, precipitation with ethanol, deprotein, decoloration, and redissolve followed by extraction with distilled water and moreover frozen-dry, was extracted from the media liquid that was centrifuged while the bodies of MPD was harvested. The total soluble part of extracellular substance was detected colorimetrically by the Anthrone Sulfuric-acid method and identified as polysaccharide. The total soluble exopolysaccharides which was observed with the method of DEAE-52 chromatography consisted of three kinds of polysaccharides. The component sugar after hydrolysis of the polysaccharides were identified as glucose, mannose, galactose and rhamnose that was determined by the sensitive pre-column derivatization high performance liquid chromatography(HPLC) method for the analysis of monosaccharide composition in polysaccharides. The exopolysaccharides of MPD presented not only much more evident activities, which were tested by means of the method of Serum Pharmacology and so on, against tumor S180 and flu virus FM in vivo, but also prominently enhanced the lymphocytosis of blood in vitro. What's more, the sulfated exopolysaccharides of Nitzschia closterIum (SEPSN) prepared by the reaction of primary exopolysaccharides of Nitzschia closterIum (PEPSN) with the modified method of Chlorosulfonic-acid Pyridine, has much more pharmacological activities than that of PEPSN. The study on pharmacology... |
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