Hoffmann J, Mendgen K
Fakultat fur Biologie, Universitat Konstanz, Konstanz, 78457, Germany.
Fungal Genet Biol. 1998 Jun;24(1-2):77-85. doi: 10.1006/fgbi.1998.1059.
We have used the fluorescent dye FM4-64 as a tracer to demonstrate bulk membrane internalization (endocytosis) and redistribution of the dye within the cytoplasm of the germ tube of the rust fungus Uromyces fabae. Staining of the hyphal membrane was detected 4 s after application of FM4-64 and reached a maximum after 1 min. The highest fluorescence intensity occurred in the apex. Subsequently, staining of the plasma membrane decreased and a subapical region of the fungal protoplast (5-20 &mgr;m from the tip) displayed increasing fluorescence with a maximum after 5 min. Fluorescence in the subapical region was redistributed to an area in the hyphal tip, which corresponds to the accumulation of apical vesicles, after 10-15 min and subsequently to a cytoplasmic region in front of the two nuclei (35-45 &mgr;m from the tip). We conclude from our measurements of membrane fluorescence that the turnover time from endocytosis to secretion of the dye amounts to 15 min. The uptake of the dye into the cytoplasm, but not membrane loading, could be inhibited completely with 5 mM NaN3 or by a temperature shift to 4 degreesC. This is the first evidence for endocytosis in a fungal germ tube. Copyright 1998 Academic Press.
我们使用荧光染料FM4-64作为示踪剂，来证明膜的大量内化（内吞作用）以及该染料在锈菌蚕豆单胞锈菌芽管细胞质内的重新分布。在施加FM4-64后4秒检测到菌丝膜染色，1分钟后达到最大值。最高荧光强度出现在顶端。随后，质膜染色减少，真菌原生质体的亚顶端区域（距顶端5-20μm）荧光增强，5分钟后达到最大值。10-15分钟后，亚顶端区域的荧光重新分布到菌丝顶端的一个区域，该区域对应顶端小泡的积累，随后又分布到两个细胞核前方的细胞质区域（距顶端35-45μm）。根据我们对膜荧光的测量结果，我们得出结论，染料从内吞作用到分泌的周转时间为15分钟。5 mM叠氮化钠或温度降至4℃可完全抑制染料进入细胞质，但不能抑制膜加载。这是真菌芽管内吞作用的首个证据。版权所有1998年学术出版社。
