Optical properties of microbial cells ans sensing the light direction in phototaxis

微生物细胞在趋光性中感知光方向的光学特性

• 批准号: 390131350
• 负责人: Professor Dr. Jan Gerrit Korvink
• 金额: --
• 依托单位: Institut für Biologie III
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/390131350?language=en
• 关键词: Optical; properties; microbial; cells; ans

Sunlight, which drives photosynthesis, is the most important energy supplier for life on Earth. Photosynthetic cyanobacteria are the ancestors of chloroplasts and they are still very important primary producers in almost all habitats. Our current understanding of the physiology and the metabolism of cyanobacteria is largely based on studies of pure lab-grown cultures in suspension. Moreover, studies in recent years have mainly focused on the analysis of photosynthesis and biotechnological applications of these oxygenic phototrophs. We recently analysed the micro-optic properties of cyanobacterial cells and revealed the importance of these physical cellular characteristics for sensing light direction for phototaxis. In addition, there is emerging evidence that the optical properties of chloroplasts might be important for optimizing photosynthetic light harvesting in low light environments. The spherical cyanobacterium Synechocystis 6803 moves on surfaces using type IV pili towards or away from a light source. The single bacterial cell acts as a very effective micro-lens, focusing a sharp image of the light source close to the opposite (non-illuminated) side of the cell. This bright light spot locally triggers a so far unexplored signal transduction chain, which then controls movement of the cell in response to the light source. Our preliminary investigations with other microorganisms indicate that such micro-optic effects are not confined to spherical cyanobacteria or even to phototrophs. We hypothesize that these micro-optic effects may have important implications for light-sensing, interaction with the environment and UV photodamage. For this proposal, we wish to explore physical properties of cyanobacterial cells by new optical methods and to reveal the signal transduction pathway from the photoreceptors to the motility machinery. Probing optical effects at scales close to wavelength of light requires specialized physical expertise. Therefore we have developed a highly interdisciplinary project combining complementary skills in physics and (photo)biology. In a first approach we will use physical and biological methods to measure the optical properties of very small cells. More generally, we aim to develop a new way to probe molecular responses to optical stimulation at the single-cell scale with high optical resolution. This will be the base for the generation of a comprehensive model for directional light sensing in single-celled organisms.

太阳光驱动光合作用，是地球上生命最重要的能量供应者。光合蓝细菌是叶绿体的祖先，它们仍然是几乎所有栖息地中非常重要的初级生产者。我们目前对蓝藻的生理和代谢的理解主要是基于对纯实验室悬浮培养物的研究。此外，近年来的研究主要集中在这些产氧光合生物的光合作用和生物技术应用的分析。我们最近分析了蓝藻细胞的微观光学特性，并揭示了这些物理细胞特性的重要性，用于感测光的方向。此外，有新的证据表明，叶绿体的光学特性可能是重要的优化光合光收集在低光环境。球形蓝细菌集胞藻6803使用IV型皮利在表面上朝向或远离光源移动。单个细菌细胞充当非常有效的微透镜，将光源的清晰图像聚焦到细胞的相对侧（非照明侧）。这个明亮的光点局部触发了一个迄今为止尚未探索的信号转导链，然后控制细胞响应光源的运动。 我们对其他微生物的初步调查表明，这种微光学效应并不局限于球形蓝藻，甚至光养生物。我们推测，这些微光学效应可能对光传感，与环境的相互作用和紫外光损伤有重要的影响。因此，我们希望通过新的光学方法来探索蓝藻细胞的物理特性，并揭示从光感受器到运动机制的信号转导途径。在接近光波长的尺度上探测光学效应需要专业的物理知识。因此，我们开发了一个高度跨学科的项目，结合了物理学和（照片）生物学的互补技能。在第一种方法中，我们将使用物理和生物方法来测量非常小的细胞的光学特性。更一般地说，我们的目标是开发一种新的方法来探测分子的光刺激反应在单细胞规模与高光学分辨率。这将是一个全面的模型，在单细胞生物体中的定向光传感的生成的基础。