Plant Research Group, Department of Biology, MRC 306, Rensselaer Polytechnic Institute, 12180-3590, Troy, NY, USA.
Planta. 1990 Feb;180(3):361-71. doi: 10.1007/BF00198787.
Transmission electron microscopy and immunocytological labeling were used to localize the 32-kilodalton (kDa) protein (DI polypeptide) of photosystem II in different cell types of the cyanobionts within leaf cavities of Azolla caroliniana Willd. The 32-kDa protein binds the secondary electron acceptor QB, and is highly conserved between plants and cyanobacteria. Three antisera, specific for different epitopes of the 32-kDa protein, were used as primary antibodies. Immunologically recognizable 32-kDa protein was localized on membranes of Azolla chloroplasts, vegetative cyanobacterial cells, akinetes, and heterocysts that were at all stages of the differentiation process. The 32-kDa protein was not detected in nonphotosynthetic endosymbiotic bacteria found within leaf cavities. The amount of the 32-kDa protein observed in different cyanobacterial cell types was dependent upon the primary antiserum used and membrane orientation within a cell with respect to the plane of sectioning. Therefore, although 32-kDa protein was present in all three cyanobacterial cell types and clear trends in labeling patterns could be elucidated, it was not possible to quantitate the amounts of protein with respect to either cell type or leaf-cavity age.
利用透射电子显微镜和免疫细胞化学标记法，对满江红（Azolla caroliniana Willd.）叶腔中蓝藻共生体不同细胞类型中光合系统 II 的 32kDa 蛋白（DI 多肽）进行定位。该 32kDa 蛋白与次级电子受体 QB 结合，在植物和蓝藻之间高度保守。三种抗血清，针对 32kDa 蛋白的不同表位，被用作一抗。在满江红叶绿体膜、营养性蓝藻细胞、静息孢子和异形胞上，均可检测到具有免疫识别能力的 32kDa 蛋白，这些细胞处于不同的分化阶段。在叶腔中发现的非光合内共生细菌中，未检测到 32kDa 蛋白。在不同的蓝藻细胞类型中观察到的 32kDa 蛋白的量取决于所使用的一抗和细胞内相对于切片平面的膜方向。因此，尽管 32kDa 蛋白存在于三种蓝藻细胞类型中，并且可以清楚地阐明标记模式的趋势，但无法对蛋白的量相对于细胞类型或叶腔年龄进行定量。
