Human sperm steer with second harmonics of the flagellar beat.
Human sperm steer with second harmonics of the flagellar beat.
复制标题
DOI：
10.1038/s41467-017-01462-y
复制
发表时间：
2017-11-10
影响因子：
16.6
通讯作者：
Elgeti J
中科院分区：
文献类型：
--
作者：
Saggiorato G;Alvarez L;Jikeli JF;Kaupp UB;Gompper G;Elgeti J
精子由沿着鞭毛传播的弯曲波推动。为了控制感觉线索的梯度，精子调整鞭毛波形。对称和不对称波形分别导致直线和弯曲的游泳路径。已经提出了导致空间不对称波形的两种机制：平均鞭毛曲率和屈曲。我们对人类精子的鞭毛进行成像，其头部与表面相连。波形的特征在于基频拍频及其二次谐波。和声的叠加在时间上而非空间上打破了节拍对称性。结果，精子围绕束缚点旋转。旋转速度由二次谐波幅度和相位决定。女性性激素黄体酮的刺激增强了二次谐波的贡献，从而调节精子的旋转。其他有鞭毛的细胞中存在更高的拍频成分；因此，这种转向机制可能会广泛使用，并可能激发合成微型游泳器的设计。精子操纵的机制尚不完全清楚。作者发现，两个谐波的叠加在时间上而不是空间上打破了鞭毛节拍对称性，并且这种机制被性激素黄体酮增强，从而改变了运动模式。
Sperm are propelled by bending waves traveling along their flagellum. For steering in gradients of sensory cues, sperm adjust the flagellar waveform. Symmetric and asymmetric waveforms result in straight and curved swimming paths, respectively. Two mechanisms causing spatially asymmetric waveforms have been proposed: an average flagellar curvature and buckling. We image flagella of human sperm tethered with the head to a surface. The waveform is characterized by a fundamental beat frequency and its second harmonic. The superposition of harmonics breaks the beat symmetry temporally rather than spatially. As a result, sperm rotate around the tethering point. The rotation velocity is determined by the second-harmonic amplitude and phase. Stimulation with the female sex hormone progesterone enhances the second-harmonic contribution and, thereby, modulates sperm rotation. Higher beat frequency components exist in other flagellated cells; therefore, this steering mechanism might be widespread and could inspire the design of synthetic microswimmers. The mechanism allowing sperm to steer is not fully understood. The authors find that superposition of two harmonic waves breaks the flagellar beat symmetry temporally rather than spatially, and that this mechanism is enhanced by the sexual hormone progesterone, which changes the motility pattern.
登录
查看更多内容
影响因子：
3.7
作者：
Guidobaldi HA;Teves ME;Uñates DR;Anastasía A;Giojalas LC
通讯作者：
Giojalas LC
影响因子：
8.6
作者：
Friedrich, Benjamin M.;Juelicher, Frank
通讯作者：
Juelicher, Frank
影响因子：
3.4
作者：
Elgeti, Jens;Kaupp, U. Benjamin;Gompper, Gerhard
通讯作者：
Gompper, Gerhard
影响因子：
3.9
作者：
Bennett, Rachel R.;Golestanian, Ramin
通讯作者：
Golestanian, Ramin
影响因子：
3.3
作者：
Camalet, S;Jülicher, F
通讯作者：
Jülicher, F