Temporal sampling, resetting, and adaptation orchestrate gradient sensing in sperm
Temporal sampling, resetting, and adaptation orchestrate gradient sensing in sperm
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DOI：
10.1083/jcb.201204024
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发表时间：
2012-09-17
影响因子：
7.8
通讯作者：
Kaupp, U. Benjamin
中科院分区：
文献类型：
--
作者：
Kashikar, Nachiket D.;Alvarez, Luis;Kaupp, U. Benjamin
精子在化学梯度中航行，暴露于周期性的化学引诱物分子流中。周期性刺激引起控制循环转向反应的Ca2+振荡。目前尚不清楚精子如何在周期性刺激期间采样化学引诱物分子并调节其敏感性。我们报告说，海胆精子采样分子为0.2 - 0.6秒前产生的Ca2+反应。在Ca2+响应期间传递的额外分子通过引起终止响应的显著Ca2+下降来重置细胞;这种重置之后是新的Ca2+上升。刺激后，精子适应其敏感性遵循韦伯-费希纳定律。考虑到单分子的敏感性，我们估计，精子可以注册一个最小的梯度为0.8 fM/μ m，并吸引从远至4.7 mm。许多微生物的感觉刺激梯度沿着周期性的路径翻译成一个时间模式的细胞响应的刺激的空间分布。时间采样、重置和适应的演示也可能控制这些生物体的梯度感知。
Sperm, navigating in a chemical gradient, are exposed to a periodic stream of chemoattractant molecules. The periodic stimulation entrains Ca2+ oscillations that control looping steering responses. It is not known how sperm sample chemoattractant molecules during periodic stimulation and adjust their sensitivity. We report that sea urchin sperm sampled molecules for 0.2-0.6 s before a Ca2+ response was produced. Additional molecules delivered during a Ca2+ response reset the cell by causing a pronounced Ca2+ drop that terminated the response; this reset was followed by a new Ca2+ rise. After stimulation, sperm adapted their sensitivity following the Weber-Fechner law. Taking into account the single-molecule sensitivity, we estimate that sperm can register a minimal gradient of 0.8 fM/mu m and be attracted from as far away as 4.7 mm. Many microorganisms sense stimulus gradients along periodic paths to translate a spatial distribution of the stimulus into a temporal pattern of the cell response. Orchestration of temporal sampling, resetting, and adaptation might control gradient sensing in such organisms as well.