Shape and Dynamics of Tip-Growing Cells
Shape and Dynamics of Tip-Growing Cells
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DOI：
10.1016/j.cub.2009.10.075
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发表时间：
2009-12-29
期刊：
影响因子：
9.2
通讯作者：
Mahadevan, L.
中科院分区：
文献类型：
--
作者：
Campas, Otger;Mahadevan, L.
有壁细胞具有重塑其形状的能力，同时维持可达到10个大气压的内部膨压[1-7]。虽然这是无可争议的，这需要一个严格的和同时调节细胞壁组装和力学，以前的理论研究的尖端生长集中在细胞壁的机械行为或其组装[8-14]。为了研究生长和力学之间的相互作用，在形成一个有壁的细胞，我们研究了特别简单的几何形状的尖端生长的细胞[1，3，159 16]，通过组装和细胞壁在细胞的顶端区域的扩展延长。我们描述了所观察到的不可逆膨胀的细胞壁在生长过程中的膨胀压力的作用下，在附近的生长尖端的材料源喂养的一个不均匀的粘性流体壳的延伸。这使我们能够从理论上确定细胞的半径和它的生长速度的膨压和分泌速率和流变学的细胞壁材料。我们推导出简单的缩放律的几何形状的细胞，并发现一个单一的无量纲参数，其特征在于细胞壁组装和扩张的相对作用，是足以解释所观察到的变化的尖端生长的细胞的形状。更一般地说，我们的描述提供了一个框架来理解植物（花粉管[17]，根毛等[18]），真菌（菌丝生长[19，20]和分裂和出芽酵母[3]）和一些细菌[21]中的细胞生长和重塑，在尖端生长和扩散生长的背景下。
Walled cells have the ability to remodel their shape while sustaining an internal turgor pressure that can reach values up to 10 atmospheres [1-7]. Although it is undisputed that this requires a tight and simultaneous regulation of cell wall assembly and mechanics, previous theoretical studies on tip growth focused either on the mechanical behavior of the cell wall or on its assembly [8-14]. To study the interplay between growth and mechanics in shaping a walled cell, we examine the particularly simple geometry of tip-growing cells [1, 3, 159 16], which elongate via the assembly and expansion of cell wall in the apical region of the cell. We describe the observed irreversible expansion of the cell wall during growth as the extension of an inhomogeneous viscous fluid shell under the action of turgor pressure, fed by a material source in the neighborhood of the growing tip. This allows us to determine theoretically the radius of the cell and its growth velocity in terms of the turgor pressure and the secretion rate and rheology of the cell wall material. We derive simple scaling laws for the geometry of the cell and find that a single dimensionless parameter, which characterizes the relative roles of cell wall assembly and expansion, is sufficient to explain the observed variability in shapes of tip-growing cells. More generally, our description provides a framework to understand cell growth and remodeling in plants (pollen tubes [17], root hairs, etc. [18]), fungi (hyphal growth [19, 20] and fission and budding yeast [3]), and some bacteria [21], in the context of both tip growth and diffuse growth.