Coordination of size-control, reproduction and generational memory in freshwater planarians.
Coordination of size-control, reproduction and generational memory in freshwater planarians.
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淡水涡虫体型控制、繁殖和世代记忆的协调。
DOI：
10.1088/1478-3975/aa70c4
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发表时间：
2017
期刊：
影响因子：
2
通讯作者：
Collins,Eva-MariaS
中科院分区：
文献类型：
--
作者：
Yang,Xingbo;Kaj,KelsonJ;Schwab,DavidJ;Collins,Eva-MariaS
揭示通过二元分裂繁殖的生物体的大小、生长和分裂速度的控制机制意味着了解其生命周期的基本原理。最近的研究主要集中在细菌和酵母的分裂率是如何调节的，但是这个问题还没有在更复杂的多细胞生物中得到解决。在几年的时间里，我们收集了两种淡水涡虫的生长和无性繁殖的独特的大规模数据集，这两种涡虫是通过横向裂变和头部和尾部的后续再生来繁殖成新的涡虫的，它们是日本Dugesia japonica和Girardia tigrina。我们表明，世代依赖的记忆效应在涡虫繁殖需要考虑到准确捕获实验数据。为了实现这一目标，我们开发了一种新的附加模型，该模型混合了基于涡虫大小、生长和分裂间隔时间的多种尺寸控制策略。我们的模型量化了每种策略在混合动态中的比例，揭示了两种涡虫物种以协调的方式利用不同策略进行大小控制的能力。此外，我们发现这两个物种的头尾后代采用不同的机制来监测和触发它们的繁殖周期。因此，我们不仅在物种之间发现了策略的多样性，而且在物种内部也发现了正面和反面策略的多样性。与现有的2D模型相比，我们的加性模型提供了两个优势，后者将多变量分割率函数拟合到数据中以进行大小控制：首先，它可以适合相对较小的数据集，因此可以应用于可用数据有限的系统。其次，它提供了新的生物学见解，因为它明确显示了不同大小控制策略对每种后代类型的贡献。
Uncovering the mechanisms that control size, growth, and division rates of organisms reproducing through binary division means understanding basic principles of their life cycle. Recent work has focused on how division rates are regulated in bacteria and yeast, but this question has not yet been addressed in more complex, multicellular organisms. We have, over the course of several years, assembled a unique large-scale data set on the growth and asexual reproduction of two freshwater planarian species, Dugesia japonica and Girardia tigrina, which reproduce by transverse fission and succeeding regeneration of head and tail pieces into new planarians. We show that generation-dependent memory effects in planarian reproduction need to be taken into account to accurately capture the experimental data. To achieve this, we developed a new additive model that mixes multiple size control strategies based on planarian size, growth, and time between divisions. Our model quantifies the proportions of each strategy in the mixed dynamics, revealing the ability of the two planarian species to utilize different strategies in a coordinated manner for size control. Additionally, we found that head and tail offspring of both species employ different mechanisms to monitor and trigger their reproduction cycles. Thus, we find a diversity of strategies not only between species but between heads and tails within species. Our additive model provides two advantages over existing 2D models that fit a multivariable splitting rate function to the data for size control: firstly, it can be fit to relatively small data sets and can thus be applied to systems where available data is limited. Secondly, it enables new biological insights because it explicitly shows the contributions of different size control strategies for each offspring type.