McDaniel D P, Roberson R W
Molecular and Cellular Biology Program, Department of Plant Biology, Arizona State University, Tempe, Arizona 85287-1601, USA.
Fungal Genet Biol. 2000 Dec;31(3):233-44. doi: 10.1006/fgbi.2000.1249.
We have used video-enhanced light microscopy and digital image processing to characterize the intracellular motility and positioning of vesicles ( approximately 1-microm diameter) and mitochondria in growing hyphal tip cells of Allomyces macrogynus. These observations were coupled with cytoskeletal inhibitory experiments to define the roles of the microtubule and actin cytoskeletons in organelle translocation and positioning. Vesicles and mitochondria were abundant in apical and subapical hypha regions. Vesicles traveled along paths that were parallel to the longitudinal axis of the cell. Anterograde (i.e., toward the hyphal apex) and retrograde (i.e., away from the hyphal apex) movements of vesicles occurred at average rates of 4.0 and 2.2 microm/s, respectively. Bidirectional travel of vesicles along common paths was noted in the cortical cytoplasm. Mitochondria were aligned mostly parallel to the long axis of the hypha, except those extending into the hyphal apex, which were oriented toward the Spitzenkörper. In regions of the subapical hypha mitochondria were often restricted to the cortical cytoplasm and nuclei occupied the central cytoplasmic region. Mitochondria displayed rapid anterograde movements reaching speeds of 3.0 microm/s, but primarily maintained a constant position relative to either the advancing cytoplasm or the lateral cell wall. Cytoskeletal disruption experiments showed that the positioning of mitochondria and motility of vesicles and mitochondria were microtubule-based and suggested that the actin cytoskeleton played uncertain roles.
我们利用视频增强光学显微镜和数字图像处理技术，对大雌异水霉生长的菌丝顶端细胞中囊泡（直径约1微米）和线粒体的细胞内运动及定位进行了表征。这些观察结果与细胞骨架抑制实验相结合，以确定微管和肌动蛋白细胞骨架在细胞器转运和定位中的作用。囊泡和线粒体在顶端和亚顶端菌丝区域丰富。囊泡沿着与细胞纵轴平行的路径移动。囊泡的顺行（即朝向菌丝顶端）和逆行（即远离菌丝顶端）运动的平均速率分别为4.0和2.2微米/秒。在皮质细胞质中，观察到囊泡沿着共同路径进行双向移动。线粒体大多与菌丝的长轴平行排列，除了那些延伸到菌丝顶端的线粒体，它们朝向孢子体。在亚顶端菌丝区域，线粒体通常局限于皮质细胞质，而细胞核占据中央细胞质区域。线粒体表现出快速的顺行运动，速度可达3.0微米/秒，但主要相对于前进的细胞质或外侧细胞壁保持恒定位置。细胞骨架破坏实验表明，线粒体的定位以及囊泡和线粒体的运动是以微管为基础的，并且表明肌动蛋白细胞骨架发挥的作用尚不确定。
