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Abstract：
This article relates personal recollections and starts with the origin of electron microscopy in the sixties of the previous century at the University of Amsterdam. Novel fixation and embedding techniques marked the discovery of the internal bacterial structures not visible by light microscopy. A special status became reserved for the freeze-fracture technique. By freeze-fracturing chemically fixed cells, it proved possible to examine the morphological effects of fixation. From there on, the focus switched from bacterial structure as such to their cell cycle. This invoked bacterial physiology and steady-state growth combined with electron microscopy. Electron-microscopic autoradiography with pulses of [3H] Dap revealed that segregation of replicating DNA cannot proceed according to a model of zonal growth (with envelope-attached DNA). This stimulated us to further investigate the sacculus, the peptidoglycan macromolecule. In particular, we focused on the involvement of penicillin-binding proteins such as PBP2 and PBP3, and their role in division. Adding aztreonam (an inhibitor of PBP3) blocked ongoing divisions but not the initiation of new ones. A PBP3-independent peptidoglycan synthesis (PIPS) appeared to precede a PBP3-dependent step. The possible chemical nature of PIPS is discussed.
摘要：
本文涉及个人的回忆，并从上个世纪六十年代阿姆斯特丹大学电子显微镜的起源开始。新颖的固定和包埋技术标志着光学显微镜看不到的内部细菌结构的发现。冻结断裂技术保留了特殊的地位。通过冷冻压裂化学固定的细胞，事实证明，可以检查固定的形态效应。从那里开始，焦点从细菌结构转移到它们的细胞周期。这引起了细菌生理学和稳态生长与电子显微镜的结合。[3H]Dap脉冲的电子显微镜放射自显影显示，根据带状生长模型（带有包膜附着的DNA），复制DNA的分离无法进行。这刺激了我们进一步研究囊,肽聚糖大分子。特别是,我们重点研究了青霉素结合蛋白如PBP2和PBP3的参与及其在分裂中的作用.添加氨曲南（PBP3的抑制剂）可阻止正在进行的分裂，但不会引发新的分裂。PBP3非依赖性肽聚糖合成(PIPS)似乎先于PBP3依赖性步骤。讨论了PIPS可能的化学性质。
