Intermediate features of cyanelle division of Cyanophora paradoxa (Glaucocystophyta) between cyanobacterial and plastid division
Intermediate features of cyanelle division of Cyanophora paradoxa (Glaucocystophyta) between cyanobacterial and plastid division
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DOI：
10.1046/j.1529-8817.2003.02132.x
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发表时间：
2003-06-01
影响因子：
2.9
通讯作者：
Hashimoto, H
中科院分区：
文献类型：
--
作者：
Iino, M;Hashimoto, H
根据其肽聚糖含量和蓝色素DNA的序列同源性，蓝囊藻的蓝色素可能是已知质体中最原始的。在这项研究中，EM观察已被用来描述Cyanophora paradoxa Korshikov的cyanelle分裂，并深入了解质体分裂的进化。胞囊的收缩涉及分裂部位的隔膜向内生长，内被膜在前缘内陷，外被膜在隔膜后面内陷。这意味着内外被膜不像其他植物的质体分裂那样同时收缩。在应用银-乌洛托品染色用于原位检测多糖后，隔膜和蓝囊被膜被染色。β-内酰胺类和万古霉素可抑制隔膜形成，这两种药物是细菌肽聚糖生物合成的强效抑制剂。这些结果表明，存在的肽聚糖在隔膜和蓝囊包膜。在划分cyanelle，一个单一的电子致密环（cyanelle环）观察到的基质面的内包膜在峡部，但没有环状结构的外包膜上检测到。因此，一个单一的，基质蓝环，如这是非常独特的，也不同于FtsZ环，这是无法检测到的TEM。这些特点表明，蓝囊藻的蓝藻分裂代表了蓝藻和质体分裂之间的中间阶段。如果所有质体的单系性是真的，那么蓝色素环和同源的内质体分裂环可能比外质体分裂环更早进化。
Cyanelles of glaucocystophytes may be the most primitive of the known plastids based on their peptidoglycan content and the sequence phylogeny of cyanelle DNA. In this study, EM observations have been made to characterize the cyanelle division of Cyanophora paradoxa Korshikov and to gain insights into the evolution of plastid division. Constriction of cyanelles involves ingrowth of the septum at the cleavage site with the inner envelope membrane invaginating at the leading edge and the outer envelope membrane invaginating behind the septum. This means the inner and outer envelope membranes do not constrict simultaneously as they do in plastid division in other plants. The septum and the cyanelle envelope became stained after a silver-methenamine staining was applied for in situ detection of polysaccharides. Septum formation was inhibited by beta-lactams and vancomycin, which are potent inhibitors of bacterial peptidoglycan biosynthesis. These results suggest the presence of peptidoglycan at the septum and the cyanelle envelope. In dividing cyanelles, a single electron-dense ring (cyanelle ring ) was observed on the stromal face of the inner envelope membrane at the isthmus, but no ring-like structures were detected on the outer envelope membrane. Thus a single, stromal cyanelle ring such as this is quite unique and also distinct from FtsZ rings, which are not detectable by TEM. These features suggest that the cyanelle division of glaucocystophytes represents an intermediate stage between cyanobacterial and plastid division. If monophyly of all plastids is true, the cyanelle ring and the homologous inner plastid dividing ring might have evolved earlier than the outer plastid dividing ring.