Silver R B
Marine Biological Laboratory, Woods Hole, Massachusetts, USA.
Cell Calcium. 1996 Aug;20(2):161-79. doi: 10.1016/s0143-4160(96)90105-0.
The role of Ca2+ in controlling cell processes (e.g. mitosis) presents an enigma in its ubiquity and selectivity. Intracellular free Ca2+ (Ca2+i) is an essential regulator of specific biochemical and physiological aspects of mitosis (e.g. nuclear envelope breakdown (NEB)). Changes in Ca2+i concentrations during mitosis in second cell-cycle sand dollar (Echinaracnius parma) blastomeres were imaged as Ca(2+)-dependent luminescence of the photoprotein aequorin with multi-spectral analytical video microscopy. Photons of this luminescence were seen as bright observable blobs (BOBs). Spatiotemporal patterns of BOBs were followed through one or more cell cycles to detect directly changes in Ca2+i, and were seen to change in a characteristic fashion prior to NEB, the onset of anaphase chromosome movement, and during cytokinesis. These patterns were observed from one cell cycle to the next in a single cell, from cell to cell, and from egg batch to egg batch. In both mitosis and synaptic transmission increases in Ca2+i concentration occurs in discrete, short-lived, highly localized pulses we name quantum emission domains (QEDs) within regions we named microdomains. Signal and statistical optical analyses of spatiotemporal BOB patterns show that many BOBs are linked by constant displacements in space-time (velocity). Linked BOBs are thus nonrandom and are classified as QEDS. Analyses of QED patterns demonstrated that the calcium signals required for NEB are nonrandom, and are evoked by an agent(s) generated proximal to a Ca2+i-QED; models of waves, diffusible agonists and Ca(2+)-activated Ca2+ release do not fit pre-NEB cell data. Spatial and temporal resolution of this multispectral approach significantly exceeds that reported for other methods, and avoids the perturbations associated with many fluorescent Ca2+ reporters that interfere with cells being studied (Ca(2+)-buffering, UV toxicity, etc.). Spatiotemporal patterns of Ca2+i-QED can control so many different processes, i.e. specific frequencies used to control particular processes. Predictive and structured patterns of calcium signals (e.g. a language expressed in Ca2+) may selectively regulate specific Ca(2+)-dependent cellular processes.
钙离子在控制细胞过程（如细胞有丝分裂）中所起的作用，其普遍性和选择性令人费解。细胞内游离钙离子（Ca2+i）是有丝分裂特定生化和生理方面（如核膜破裂（NEB））的重要调节因子。利用多光谱分析视频显微镜，将海胆（Echinaracnius parma）第二次细胞周期卵裂球有丝分裂过程中Ca2+i浓度的变化，成像为光蛋白水母发光蛋白依赖Ca2+的发光。这种发光的光子被视为明亮的可观察斑点（BOBs）。通过一个或多个细胞周期追踪BOBs的时空模式，以直接检测Ca2+i的变化，并观察到在核膜破裂、后期染色体运动开始之前以及胞质分裂期间，其以特征性方式发生变化。在单个细胞中、从一个细胞到另一个细胞以及从一批卵到另一批卵中，都观察到了从一个细胞周期到下一个细胞周期的这些模式。在有丝分裂和突触传递中，Ca2+i浓度的增加都发生在离散的、短暂的、高度局部化的脉冲中，我们将其命名为微区内的量子发射域（QEDs）。对时空BOB模式的信号和统计光学分析表明，许多BOB通过时空上的恒定位移（速度）相互关联。因此，相互关联的BOB是非随机分布的，并被归类为QEDs。对QED模式的分析表明，核膜破裂所需的钙信号是非随机的，并且是由靠近Ca2+i - QED产生的一种或多种因子诱发的；波、可扩散激动剂和Ca2+激活的Ca2+释放模型均不符合核膜破裂前的细胞数据。这种多光谱方法的空间和时间分辨率显著超过了其他方法所报道的分辨率，并且避免了许多干扰被研究细胞的荧光Ca2+报告分子所带来的干扰（Ca2+缓冲、紫外线毒性等）问题。Ca2+i - QED的时空模式可以控制如此多不同的过程，即用于控制特定过程的特定频率。钙信号的预测性和结构化模式（例如以Ca2+表达的一种语言）可能会选择性地调节特定的Ca2+依赖细胞过程。
