Barelle Caroline J, Bohula Erin A, Kron Stephen J, Wessels Deborah, Soll David R, Schäfer Annette, Brown Alistair J P, Gow Neil A R
Department of Molecular and Cell Biology, Institute of Molecular Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom.
Eukaryot Cell. 2003 Jun;2(3):398-410. doi: 10.1128/EC.2.3.398-410.2003.
Candida albicans forms unconstricted hyphae in serum-containing medium that are divided into discrete compartments. Time-lapse photomicroscopy, flow cytometry, and a novel three-dimensional imaging system were used to demonstrate that the kinetics and cell cycle events accompanying hyphal development were correlated with dynamic changes in vacuole morphology and the pattern of vacuole inheritance. Apical cells of hyphae underwent continuous extension before and after the first cytokinesis event. However, the resulting mother cell and sub-apical compartments did not immediately reenter the cell cycle and instead underwent cell cycle arrest before reentering the cycle. Vacuole was inherited asymmetrically at cytokinesis so that the distal, arrested compartments inherited most vacuole and the growing apical cell inherited most cytoplasm. Hydroxyurea release experiments demonstrated that the arrested, vacuolated hyphal compartments were in the G(1) phase of the cycle. The period of cell cycle arrest was decreased by the provision of assimilatable forms of nitrogen, suggesting that the hyphal cell cycle is regulated by nitrogen limitation that results in sup-apical cell cycle arrest. This pattern of growth is distinct from that of the synchronous, symmetrical development of pseudohyphae of C. albicans and other yeast species. These observations suggest that the cellular vacuole space correlates with alterations in the cell cycles of different cell types and that the total organelle space may influence size-regulated functions and hence the timing of the eukaryotic cell cycle.
白色念珠菌在含血清培养基中形成无缢缩的菌丝，这些菌丝被分为离散的隔室。采用延时显微镜、流式细胞术和一种新型三维成像系统来证明，伴随菌丝发育的动力学和细胞周期事件与液泡形态的动态变化以及液泡遗传模式相关。菌丝的顶端细胞在第一次胞质分裂事件前后持续延伸。然而，产生的母细胞和亚顶端隔室并未立即重新进入细胞周期，而是在重新进入周期之前经历细胞周期停滞。液泡在胞质分裂时不对称遗传，因此远端的停滞隔室继承了大部分液泡，而生长中的顶端细胞继承了大部分细胞质。羟基脲释放实验表明，停滞的、有液泡的菌丝隔室处于细胞周期的G(1)期。提供可同化形式的氮可缩短细胞周期停滞期，这表明菌丝细胞周期受氮限制调节，导致亚顶端细胞周期停滞。这种生长模式与白色念珠菌和其他酵母物种假菌丝的同步、对称发育模式不同。这些观察结果表明，细胞液泡空间与不同细胞类型的细胞周期变化相关，并且细胞器总体积可能影响大小调节功能，从而影响真核细胞周期的时间安排。
