白念珠菌胞壁碱溶性β-葡聚糖的分离、纯化和分析

Isolation and Purification of the Alkali－ solubleβ－ glucan from Cell Wall of Candida albicans

目的 分离纯化白念珠菌胞壁碱溶性β－葡聚糖，并分析其物理化学性质和结构。 方法与结果 白念珠菌标准株 IDC1d经 YEPD培养基 28℃、 18 h培养，收集酵母相细胞， 0.75 mol/L NaOH液提取，乙醇沉淀，得粗多糖。采用红外光谱、苯酚－硫酸法、蒽酮－硫酸法、 3,5－二硝基水杨酸法、考马斯亮蓝法定性分析粗多糖。粗多糖不含还原糖，但含有蛋白质。粗多糖经 Sephadex G－ 200凝胶柱层析纯化。纸层析、凝胶柱层析鉴定所得多糖的纯度，表明其为均一物质。凝胶柱层析测定相对分子质量约为 89 125.09。多糖经完全酸水解，硅胶薄层层析和气相色谱分析单糖组分，结果表明其为 D－葡萄糖聚合成的多糖。红外光谱提示多糖糖苷键为β型。高碘酸氧化和 Smith降解结果表明多糖包含 1→ 3和 1→ 6两种连接键，推测前者为主链键型，后者为支链键型。

Objective To isolate and purity the alkali－ solubleβ－ glucan from the cell wall of Candida albicans and to analyze the physico－ chemical properties and structure of it. Methods and Results After a standard strain of Candida albicans (IDC1d) was fermented on YEPD medium for 18 h at 28℃ , yeast cells were digested with 3％ NaOH solution and then crude glucan was extracted and precipitated by alcohol. Crudeβ－ glucans was purified by Sephadex G－ 200 gel column chromatography. Paper chromatography and gel column chromatography were used to determine the purity ofβ－ glucan, which was shown to be homogenous. The molecular weight of it was estimated to be 89 125.09 by gel column chromatography.β－ glucan obtained from the cell wall of Candida albicans was composed of D－ glucose only. Conclusionβ－ glucan is an important component of the cell wall of C.albicans.