Confocal imaging has shown that CELLULOSE SYNTHASE (CESA) particles move through the plasma membrane as they synthesize cellulose. However, the resolution limit of confocal microscopy circumscribes what can be discovered about these tiny biosynthetic machines. Here, we applied Structured Illumination Microscopy (SIM), which improves resolution two-fold over confocal or widefield imaging, to explore the dynamic behaviors of CESA particles in living plant cells. SIM imaging reveals that Arabidopsis thaliana CESA particles are more than twice as dense in the plasma membrane as previously estimated, helping explain the dense arrangement of cellulose observed in new wall layers. CESA particles tracked by SIM display minimal variation in velocity, suggesting coordinated control of CESA catalytic activity within single complexes and that CESA complexes might move steadily in tandem to generate larger cellulose fibrils or bundles. SIM data also reveal that CESA particles vary in their overlaps with microtubule tracks and can complete U-turns without changing speed. CESA track patterns can vary widely between neighboring cells of similar shape, implying that cellulose patterning is not the sole determinant of cellular growth anisotropy. Together, these findings highlight SIM as a powerful tool to advance CESA imaging beyond the resolution limit of conventional light microscopy.

中文翻译：

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超分辨率成像阐明了纤维素合酶的新动态行为

共聚焦成像显示，纤维素合成酶 (CESA) 颗粒在合成纤维素时穿过质膜。然而，共聚焦显微镜的分辨率限制限制了关于这些微型生物合成机器的发现。在这里，我们应用结构照明显微镜 (SIM) 来探索 CESA 粒子在活植物细胞中的动态行为，它比共聚焦或广角成像提高了两倍的分辨率。SIM 成像显示拟南芥 CESA 颗粒在质膜中的密度是先前估计的两倍多，这有助于解释在新壁层中观察到的纤维素的密集排列。SIM 跟踪的 CESA 粒子显示出最小的速度变化，表明在单个复合物内协调控制 CESA 催化活性，并且 CESA 复合物可能串联稳定移动以产生更大的纤维素原纤维或束。SIM 数据还显示，CESA 粒子在与微管轨道的重叠方面有所不同，并且可以在不改变速度的情况下完成掉头。CESA 轨道模式在形状相似的相邻细胞之间可能差异很大，这意味着纤维素模式不是细胞生长各向异性的唯一决定因素。总之，这些发现突出表明 SIM 是一种强大的工具，可以推动 CESA 成像超越传统光学显微镜的分辨率极限。CESA 轨道模式在形状相似的相邻细胞之间可能差异很大，这意味着纤维素模式不是细胞生长各向异性的唯一决定因素。总之，这些发现突出表明 SIM 是一种强大的工具，可以推动 CESA 成像超越传统光学显微镜的分辨率极限。CESA 轨道模式在形状相似的相邻细胞之间可能差异很大，这意味着纤维素模式不是细胞生长各向异性的唯一决定因素。总之，这些发现突出表明 SIM 是一种强大的工具，可以推动 CESA 成像超越传统光学显微镜的分辨率极限。