Hazen K C, Hazen B W
Department of Pathology, University of Virginia Health Sciences Center, Charlottesville 22908.
Infect Immun. 1992 Apr;60(4):1499-508. doi: 10.1128/iai.60.4.1499-1508.1992.
Ultrastructural and biochemical analyses of hydrophobic and hydrophilic yeast cell surface proteins of Candida albicans were performed. Hydrophobic and hydrophilic yeast cells were obtained by growth at 23 and 37 degrees C, respectively. In addition, hydrophilic yeast cells were converted to surface hydrophobicity by treatment with tunicamycin and dithiothreitol. When freeze-etched cells were examined, the temperature-induced hydrophilic cells had long (0.198 micron), compact, evenly distributed fibrils while temperature-induced hydrophobic cells had short (0.085 micron), blunt fibrils. Hydrophobic microsphere attachment to the hydrophobic cells occurred at the basement of and within the short fibril layer. Dithiothreitol-induced hydrophobic cells had the long fibrils removed; tunicamycin-induced hydrophobic cells retained some of the long fibrils, but the fibrils were less compact and more aggregated than the untreated controls. These results suggest that the long fibrils prevent hydrophobic microsphere attachment to the hydrophobic area of the cell surface. This was confirmed by assessing the hydrophobic avidity of hydrophobic yeast cell populations differing in fibril density and arrangement. 125I-labelled surface proteins from hydrophobic and hydrophilic cells were compared after separation by hydrophobic interaction chromatography-high-performance liquid chromatography and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. The yeast cell populations had hydrophilic proteins of similar molecular masses (greater than 200 kDa), but the hydrophilic cells possessed at least two additional proteins (ca. 63 and 69 to 71 kDa). Hydrophobic surface proteins appeared to be similar. However, the amount of total radiolabelled hydrophobic proteins was approximately 10-fold higher for the hydrophobic cells than for the hydrophilic cells. This result agrees with the ultrastructural observations which showed that yeast cell surface hydrophobic proteins are masked by hydrophilic high-molecular-mass surface fibrils. Taken together, the data indicate that yeast cell hydrophobicity is not determined by differences in surface hydrophobic proteins but by the presence of hydrophilic, surface fibrils.
对白色念珠菌疏水性和亲水性酵母细胞表面蛋白进行了超微结构和生化分析。疏水性和亲水性酵母细胞分别通过在23℃和37℃下培养获得。此外，亲水性酵母细胞经衣霉素和二硫苏糖醇处理后转变为表面疏水性。当检查冷冻蚀刻细胞时，温度诱导的亲水性细胞具有长（0.198微米）、紧密、均匀分布的原纤维，而温度诱导的疏水性细胞具有短（0.085微米）、钝的原纤维。疏水性微球附着于疏水性细胞发生在短原纤维层的基部和内部。二硫苏糖醇诱导的疏水性细胞的长原纤维被去除；衣霉素诱导的疏水性细胞保留了一些长原纤维，但这些原纤维不如未处理的对照紧密且更聚集。这些结果表明，长原纤维可防止疏水性微球附着于细胞表面的疏水区。通过评估原纤维密度和排列不同的疏水性酵母细胞群体的疏水亲和力，这一点得到了证实。通过疏水相互作用色谱 - 高效液相色谱分离后，比较了疏水性和亲水性细胞的125I标记表面蛋白，并通过十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳和放射自显影进行分析。酵母细胞群体具有相似分子量（大于200 kDa）的亲水性蛋白，但亲水性细胞至少还拥有另外两种蛋白（约63 kDa和69至71 kDa）。疏水性表面蛋白似乎相似。然而，疏水性细胞的总放射性标记疏水蛋白量比亲水性细胞高出约10倍。这一结果与超微结构观察结果一致，即酵母细胞表面疏水蛋白被亲水性高分子量表面原纤维所掩盖。综上所述，数据表明酵母细胞的疏水性不是由表面疏水蛋白的差异决定的，而是由亲水性表面原纤维的存在决定的。
