Riquelme M, Fischer R, Bartnicki-García S
Department of Plant Pathology, University of California, Riverside, USA.
Protoplasma. 2003;222(3-4):211-5. doi: 10.1007/s00709-003-0020-8. Epub 2003 Oct 29.
It is well established that cytoplasmic microtubules are depolymerized during nuclear division and reassembled as mitotic microtubules. Mounting evidence showing that cytoplasmic microtubules were also involved in apical growth of fungal hyphae posed the question of whether apical growth became disrupted during nuclear division. We conducted simultaneous observations of mitosis (fluorescence microscopy) and apical growth (phase-contrast microscopy) in single hyphae of Aspergillus nidulans to determine if the key parameters of apical growth (elongation rate and Spitzenkörper behavior) were affected during mitosis. To visualize nuclei during mitosis, we used a strain of A. nidulans, SRS27, in which nuclei are labeled with the green-fluorescent protein. To reveal the Spitzenkörper and measure growth with utmost precision, we used computer-enhanced videomicroscopy. Our analysis showed that there is no disruption of apical growth during mitosis. There was no decrease in the rate of hyphal elongation or any alteration in Spitzenkörper presence before, during, or after mitosis. Our findings suggest that apical growth and mitosis do not compete for internal cellular resources. Presumably, the population of cytoplasmic microtubules involved in apical growth operates independently of that involved in mitosis.
众所周知，细胞质微管在核分裂期间会解聚，并重新组装为有丝分裂微管。越来越多的证据表明，细胞质微管也参与了真菌菌丝的顶端生长，这就提出了一个问题，即顶端生长在核分裂期间是否会受到干扰。我们对构巢曲霉的单个菌丝进行了有丝分裂（荧光显微镜）和顶端生长（相差显微镜）的同步观察，以确定顶端生长的关键参数（伸长率和泡囊簇行为）在有丝分裂期间是否受到影响。为了在有丝分裂期间可视化细胞核，我们使用了构巢曲霉的一个菌株SRS27，其中细胞核用绿色荧光蛋白标记。为了最精确地显示泡囊簇并测量生长，我们使用了计算机增强视频显微镜。我们的分析表明，有丝分裂期间顶端生长没有受到干扰。在有丝分裂之前、期间或之后，菌丝伸长率没有下降，泡囊簇的存在也没有任何改变。我们的研究结果表明，顶端生长和有丝分裂不会争夺细胞内的资源。据推测，参与顶端生长的细胞质微管群体与参与有丝分裂的微管群体独立运作。
