Gruber H E, Rosario B, Hampton J C
Scan Electron Microsc. 1982(Pt 1):323-33.
Light-dark synchronized Chlamydomonas reinhardtii are most sensitive to irradiation when exposed early in the dark period of a 12 hour light: 12 hour dark regime. At this time the algae are either dividing or preparing for division. Liquid cell cultures of the 137c wild type strain exposed to 9,000 R X-irradiation exhibit 69% mortality. Monolayer cultures on Millipore filters exposed to proton irradiation (1.5 MeV protons from a positive Van de Graff accelerator) exhibit 89% mortality following a dose of 9 kilorad, and 98% mortality following 18 kilorad. Ultrastructural examination of X-irradiated cells over five days following exposure documented chloroplast and nuclear alterations which included non-nuclear condensations, swollen and ruptured nuclear envelopes and disrupted pyrenoid structure. Following both types of irradiation, both live and dead daughter cells were present within the old mother cell wall. Following both types of irradiation, cells were also observed in which there were (1) profiles resembling division conformations, and (2) chromosomes and spindle fibers present at a time not characteristic for such events in synchronized control cultures. No changes distinct to either X-ray or proton irradiation were present, indicating that, after a given level of injury, similar ultrastructural manifestations of cell damage are evident in irradiated cells.
在12小时光照：12小时黑暗的条件下，明暗同步的莱茵衣藻在黑暗期早期受到照射时对辐射最为敏感。此时，藻类要么正在分裂，要么正在为分裂做准备。137c野生型菌株的液体细胞培养物接受9000伦琴的X射线照射后，死亡率为69%。在微孔滤膜上的单层培养物接受质子照射（来自正电子范德格拉夫加速器的1.5兆电子伏特质子），剂量为9千拉德后死亡率为89%，18千拉德后死亡率为98%。对照射后五天内的X射线照射细胞进行超微结构检查，记录了叶绿体和细胞核的变化，包括非核凝聚、核膜肿胀和破裂以及类囊体结构破坏。两种照射后，在旧的母细胞壁内都存在活的和死的子细胞。两种照射后，还观察到细胞出现以下情况：（1）呈现出类似分裂构象的形态，（2）在同步对照培养物中这些事件不具有特征性的时间出现染色体和纺锤体纤维。未发现X射线或质子照射特有的变化，这表明在给定的损伤水平后，照射细胞中细胞损伤的超微结构表现相似。
