Significance Of Some Of The Structure, Activity, And Classification And Identification Of Candida Cell Wall Glucan

Recently, invasive fungal infections have emerged as major causes of morbidity and mortality in immuncompromised patients, and candidiasis is the most common nosocomial mycosis. It is useful for clinical diagnosis of candidiasis, taxonomic identification of Candida, and illumination of pathogenic mechanism of Candida infections to study structure arid activity of β -glucans which are most cell wall polysaccharides of Candida.Firstly, the alkali-soluable β -glucan from cell wall of Candida albicans was isolated and identified. After a standard strain of Candida albicans (IDCId) was fermnented on YEPD medium for 18h at 28 ℃, yeast cells were extracted by 3%NaOH solution and precipitated by alcohol and then crude glucan was obtained. Qualitative analysis showed that there was protein but no reducing sugar in crude β -glucan. Crude β -glucan was purified by Sephadex G-200 gel column chromatography. Paper chromatography and gel column chromatography were used to determine the purity of β -glucan pured, and it proved that the polysaccharide showed homogenous. Its molecular weight was estimated to be 89125.09 by gel column chromatography. The results, obtained by total acid hydrolysis, silica thin layer chromatography and gas chromatography, indicated that the β -glucan was only composed of D-glucose. IR spectroscopy showed that the β -glucan had a β -glycoside linkage. It could be presumed by the results of periodate oxidation and Smith degradation that the β-glucan's main chain had 1→3 linkage and branched chain had 1→6 linkage.A method of quantitative analysis for D-glucose and D-mannose hydrolyzed from alkali-soluble β -glucan of Candida's cell wall and whole yeast phase cells of Candida by dual-wavelength thin layer scanning (TLC) technique was established. We evaluated this method on linear range, precision, accuracy and stability.We used TLC to determine D-glucose hydrolyzed from alkali-soluble β -glucan of cell wall made up of percentage of yeast phase cells' dry weight and the ratio of D-glucose to D-mannose hydrolyzed from whole yeast phase...