It was recently demonstrated that strains homozygous for either of the mating type-like loci MTL>a and MTLα of Candida albicans undergo white-opaque switching and that expression of the opaque-phase phenotype greatly enhances mating between strains. Exploiting the latter property to obtain high-frequency mating, we have characterized the cell biology of the mating process of C. albicans. Employing continuous videomicroscopy, computer-assisted three-dimensional reconstruction of living cells, and fluorescence microscopy, we have monitored the mating-associated processes of conjugation, tube formation, fusion, budding, septum formation, and daughter cell development and the spatial and temporal dynamics of nuclear migration and division. From these observations, a model for the stages in C. albicans mating is formulated. The stages include shmooing, chemotropism of conjugation tubes, fusion of tubes and nuclear association, vacuole expansion and nuclear separation in the conjugation bridge, asynchronous nuclear division in the zygote, bud growth, nuclear migration into the daughter cell, septation, and daughter cell budding. Since there was no cytological indication of karyogamy, genetic experiments were performed to assess marker segregation. Recombination was not observed, suggesting that mating takes place in the absence of karyogamy between naturally occurring, homozygous >a and α strains. This study provides the first description of the cell biology of the mating process of C. albicans.
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机译:最近发现,白色念珠菌的两个交配型样位点 MTL em> > a strong>和 MTL em>α都是纯合的菌株 em em>经历白不透明转换,并且不透明相表型的表达大大增强了菌株之间的交配。利用后一种特性获得高频交配,我们表征了 C交配过程的细胞生物学。白色的 em>。利用连续的视频显微镜,活细胞的计算机辅助三维重建和荧光显微镜,我们已经监测了与交配相关的结合,管形成,融合,出芽,隔膜形成,子细胞发育以及时空动力学过程。核迁移和分裂。从这些观察中,可以得出 C阶段的模型。制定了白色的交配。这些阶段包括sh变,共轭管的趋向性,管与核缔合的融合,共轭桥中的液泡扩展和核分离,合子中的异步核分裂,芽生长,核迁移到子代细胞,分隔和子代细胞出芽。 。由于没有细胞学上的核型结合迹象,因此进行了遗传实验以评估标记的分离。没有观察到重组,这表明在自然存在的纯合的> a strong>和α菌株之间没有核配偶的情况下发生了交配。这项研究为 C的交配过程提供了细胞生物学的第一个描述。白色的 em>。
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