Dynamic Cell Imaging: application to the diatom <i>Phaeodactylum tricornutum</i> under environmental stresses

The dynamic movement of cell organelles is an important and poorly understood component of cellular organization and metabolism. In this work we present a non-invasive non-destructive method (Dynamic Cell Imaging, DCI) based on light scattering and interferometry to monitor dynamic events within photosynthetic cells using the diatom <i>Phaeodactylum tricornutum</i> as a model system. For this monitoring we acquire for a few seconds movies of the signals that are related to the motion of dynamic structures within the cell (denoted scatterers), followed by a statistical analysis of each pixel time series. Illuminating <i>P. tricornutum</i> with LEDs of different wavelengths associated with short pulsed or continuous-wave modes of illumination revealed that dynamic movements depend on chloroplast activity, in agreement with the reduction in the number of pixels with dynamic behaviour after addition of photosystem II inhibitors. We studied <i>P. tricornutum</i> under two environmentally relevant stresses, iron and phosphate deficiency. The major dynamic sites were located within lipid droplets and chloroplast envelope membranes. By comparing standard deviation and cumulative sum analyses of the time series, we showed that within the droplets two types of scatterer movement could be observed: random motion (Brownian type) but also anomalous movements corresponding to a drift which may relate to molecular fluxes within a cell. The method appears to be valuable for studying the effects of various environments on microalgae in the laboratory as well as in natural aquatic environments. Light scattering is an alternative to fluorescence to rapidly evidence dynamic processes.Lipid droplets are the major metabolic active sites under stress.A non-destructive visualization method suitable for laboratory microalgae and aquatic samples. Light scattering is an alternative to fluorescence to rapidly evidence dynamic processes. Lipid droplets are the major metabolic active sites under stress. A non-destructive visualization method suitable for laboratory microalgae and aquatic samples.

细胞器的动态运动是细胞组织与代谢过程中至关重要却尚未被充分阐明的组成部分。本研究提出一种基于光散射与干涉测量法的无创无损方法——动态细胞成像（Dynamic Cell Imaging, DCI），以硅藻三角褐指藻（Phaeodactylum tricornutum）作为模式系统，监测光合细胞内的动态事件。本研究先采集数秒时长的、与细胞内动态结构（称为散射体（scatterers））运动相关的信号影像，随后对每个像素的时间序列开展统计分析以实现监测目标。采用不同波长的LED，并搭配短脉冲或连续波照明模式照射三角褐指藻，实验结果表明其动态运动依赖于叶绿体活性，这与添加光系统II抑制剂后呈现动态行为的像素数量减少的现象相符。本研究针对三角褐指藻施加两种环境相关胁迫：铁匮乏与磷酸盐匮乏。研究发现主要的动态位点分布于脂滴与叶绿体被膜中。通过对比时间序列的标准差与累积和分析，本研究揭示脂滴内存在两类散射体运动模式：一类为随机运动（布朗型），另一类为对应漂移的异常运动，该漂移或与细胞内的分子通量相关。该方法在实验室与自然水生环境中，均可用于研究不同环境条件对微藻的影响，具备较高应用价值。光散射可作为荧光技术的替代方案，用于快速观测动态过程。脂滴是胁迫条件下主要的代谢活跃位点。本方法是一种适用于实验室微藻与水生样本的无损可视化技术。光散射可作为荧光技术的替代方案，用于快速观测动态过程。脂滴是胁迫条件下主要的代谢活跃位点。本方法是一种适用于实验室微藻与水生样本的无损可视化技术。

搜集汇总

背景与挑战

背景概述

该数据集聚焦于动态细胞成像（DCI）技术在硅藻Phaeodactylum tricornutum中的应用，通过非侵入性光散射和干涉测量方法，监测环境胁迫（如铁和磷酸盐缺乏）下细胞器动态运动。研究发现脂滴和叶绿体包膜是主要动态位点，该方法适用于实验室和自然水生环境研究，为理解细胞代谢响应提供了新工具。