球等鞭金藻胞内和胞外多糖的分离纯化及其抑菌活性

采用分级沉淀、Sephadex G-75凝胶柱层析和DEAE-52离子交换柱层析对球等鞭金藻胞内粗多糖(IPS)进行分离；对胞外粗多糖(IEPS)则进行Sephadex G-100凝胶柱层析分离。在此基础上，分析所获多糖组分对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌和变形杆菌等细菌的抑菌活性。同时，通过紫外光谱和红外光谱测定，比较IPS和IEPS结构的异同。结果表明：IPS和IEPS均具有抑菌活性，前者抑制大肠杆菌、枯草芽孢杆菌和金黄色葡萄球菌的生长，后者抑制大肠杆菌和枯草芽孢杆菌的生长；IPS经DEAE-52纤维素柱层析分离，获得2个多糖组分：IPSⅠ和IPSⅡ。IEPS经Sephadex G-100凝胶柱层析分离，获得3个多糖组分：IEPSA、IEPSB和IEPSC。活性检测表明，IPSⅠ和IPSⅡ抑制枯草芽孢杆菌和金黄色葡萄球菌的生长；IEPSA、IEPSB和IEPSC抑制大肠杆菌的生长；紫外光谱表明，IPS和IEPS均不含核酸、游离或裸露的蛋白质和色素；IPS和IEPS的红外光谱比较相似，以半乳糖为构架，均含有酰氨取代基，但不同之处在于，后者不含硫酸取代基。

Separation and Purification of Intracellular and Extracellular Polysaccharides from Isochrysis galbana and Their Antimicrobial Activity

Two crude polysaccharides,intracellular polysaccharide(IPS) and extracellular polysaccharide(EPS),were isolated from the cells and culture supernatant of Isochrysis galbana through hot-water extraction.The separation and purification of IPS and EPS,and their antimicrobial activities against Escherichia coli,Bacillus subtilis,Staphylococcus aureus and Proteus sp.were investigate,respectively.IPS was separated by ethanol-precipitation and purified by Sephadex G-75 gel chromatography,or by DEAE-52 column chromatography,while EPS was fractionated by Sephadex G-100 gel filtration chromatography.Finally,IPS and EPS were analyzed by UV and IR spectroscopy.The results indicated that: 1) IPS could inhibit the growth of Escherichia coli,Bacillus subtilis and Staphylococcus aureus.EPS could inhibit the growth of Escherichia coli and Bacillus subtilis.2) IPS was separated into two fractions(IPS Ⅰand IPS Ⅱ) by DEAE-52 column chromatography.Both fractions could inhibit the growth of Bacillus subtilis and Staphylococcus aureus;EPS was separated by Sephadex G-100 gel filtration chromatography into three fractions(EPSA,EPSB and EPSC) with inhibitory activity against the growth of Escherichia coli;3) The IR and UV spectra of IPS and EPS showed no ester protein,nucleic acid or pigment.Typical absorption curves of IPS and EPS revealed galactose frame with pyranglycoside linkage,while EPS did not exhibit sulfate radicals in the sugar linkage.