德国德累斯顿工业大学Veikko F. Geyer研究团队提出了跳动轴丝中的扭曲-扭转耦合。该项研究成果发表在2025年2月24日出版的《自然—物理学》杂志上。

运动纤毛和鞭毛产生规则的弯曲波，由于具有特征性扭转的非平面波形，使单细胞导航成为可能。然而，目前尚不清楚三维波形的几何特性扭转与纤毛和鞭毛保守的细胞骨架核心轴丝的机械扭曲变形有何关系。

研究组表明轴丝扭曲和扭转是耦合的，扭转波沿着莱茵衣藻的跳动轴丝传播。使用散焦暗场显微镜和热周期平均法，在毫秒的时间尺度上以纳米精度解析轴丝波形的三维形状，观察从基部到尖端传播的规则异手性扭转波。为了研究观察到的扭转是否由轴丝扭转引起，研究组将金纳米粒子附着在轴丝上，并测量其在跳动过程中的横截面旋转。结果发现，在局部，轴丝横截面与弯曲平面共同旋转，证明了扭曲-扭转耦合。该研究结果证明了跳动轴丝中形状和机械变形之间的联系，并可以为轴丝内负责塑造运动纤毛跳动的运动蛋白的动力学模型提供信息。

附：英文原文

Title: Twist–torsion coupling in beating axonemes

Author: Striegler, Martin, Diez, Stefan, Friedrich, Benjamin M., Geyer, Veikko F.

Issue&Volume: 2025-02-24

Abstract: Motile cilia and flagella produce regular bending waves that enable single-cell navigation due to non-planar waveforms with characteristic torsion. However, it is not known how torsion, a geometric property of the three-dimensional waveform, relates to mechanical twist deformations of the axoneme, the conserved cytoskeletal core of cilia and flagella. Here we show that axoneme twisting and torsion are coupled and that twist waves propagate along the beating axoneme of Chlamydomonas reinhardtii algae. We resolve the three-dimensional shapes of the axonemal waveform with nanometre precision at millisecond timescales using defocused dark-field microscopy and beat-cycle averaging, observing regular hetero-chiral torsion waves propagating base to tip. To investigate whether the observed torsion results from axonemal twist, we attach gold nanoparticles to axonemes and measure their cross-section rotation during beating. We find that, locally, the axonemal cross-section co-rotates with the bending plane, evidencing twist–torsion coupling. Our results demonstrate the link between shape and mechanical deformation in beating axonemes and can inform models of the dynamics of motor proteins inside the axoneme responsible for shaping the beat of motile cilia.

DOI: 10.1038/s41567-025-02783-2

Source: https://www.nature.com/articles/s41567-025-02783-2