Selective heterogeneity in exoprotease production by Bacillus subtilis.
Selective heterogeneity in exoprotease production by Bacillus subtilis.
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枯草芽孢杆菌产生的异质性异质性。
DOI：
10.1371/journal.pone.0038574
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Stanley-Wall NR
中科院分区：
文献类型：
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作者：
Davidson FA;Seon-Yi C;Stanley-Wall NR
细菌具有复杂的信号机制，以确保最有可能在不断变化的环境中提高生存能力的行为反应。越来越明显的是，作为这种反应的一部分，细菌能够分化细胞，并能够产生多种相互排斥的共存细胞状态。这些细胞状态通常与多细胞过程有关，这些多细胞过程给整个群落带来好处，但矛盾的是，这可能对个别亚群不利。这个细胞分化过程是如何控制的，这是一个耐人寻味的问题，在很大程度上仍然是一个悬而未决的问题。在这篇文章中，我们考虑了已知发生在革兰氏阳性杆菌枯草杆菌细胞分化的一个重要方面：我们研究了两个主要调控因子DECU和Spo0A在控制胞外蛋白酶生产中的作用。最近在这一领域的工作集中在DECU在这一过程中的作用，并表明蛋白质生产中的瞬时效应是细胞反应异质性的驱动因素。在这里，使用数学建模、分析和随机模拟相结合的方法，我们对这个调控系统进行了补充分析，调查了DECU和Spo0A在胞外蛋白酶生产中的作用。在这样做的过程中，我们提出了一种双峰或系统异构性的机制，而不需要在基础监管网络中使用双稳态开关。此外，我们的分析使我们得出结论，这种异质性实际上是一个持久、稳定的特征。我们的结果表明，系统反应分为三个区域：低信号水平和高信号水平分别在所有细胞关闭和打开的情况下诱导细胞群体的单峰或未分化反应，以产生外源蛋白酶。然而，对于中等水平的信号，不同的反应是通过活动水平的扩散来预测的，这代表了典型的“押注对冲”行为。
Bacteria have elaborate signalling mechanisms to ensure a behavioural response that is most likely to enhance survival in a changing environment. It is becoming increasingly apparent that as part of this response, bacteria are capable of cell differentiation and can generate multiple, mutually exclusive co-existing cell states. These cell states are often associated with multicellular processes that bring benefit to the community as a whole but which may be, paradoxically, disadvantageous to an individual subpopulation. How this process of cell differentiation is controlled is intriguing and remains a largely open question. In this paper, we consider an important aspect of cell differentiation that is known to occur in the Gram-positive bacterium Bacillus subtilis: we investigate the role of two master regulators DegU and Spo0A in the control of extra-cellular protease production. Recent work in this area focussed the on role of DegU in this process and suggested that transient effects in protein production were the drivers of cell-response heterogeneity. Here, using a combination of mathematical modelling, analysis and stochastic simulations, we provide a complementary analysis of this regulatory system that investigates the roles of both DegU and Spo0A in extra-cellular protease production. In doing so, we present a mechanism for bimodality, or system heterogeneity, without the need for a bistable switch in the underlying regulatory network. Moreover, our analysis leads us to conclude that this heterogeneity is in fact a persistent, stable feature. Our results suggest that system response is divided into three zones: low and high signal levels induce a unimodal or undifferentiated response from the cell population with all cells OFF and ON, respectively for exoprotease production. However, for intermediate levels of signal, a heterogeneous response is predicted with a spread of activity levels, representing typical “bet-hedging” behaviour.
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影响因子：
11.3
作者：
Higgins D;Dworkin J
通讯作者：
Dworkin J
DOI：
10.1073/pnas.1002499107
发表时间：
2010-05-04
影响因子：
11.1
作者：
Chastanet, Arnaud;Vitkup, Dennis;Losick, Richard M.
通讯作者：
Losick, Richard M.
影响因子：
3.2
作者：
Hata, M;Ogura, M;Tanaka, T
通讯作者：
Tanaka, T
影响因子：
3.2
作者：
KUNST, F;RAPOPORT, G
通讯作者：
RAPOPORT, G
影响因子：
9.9
作者：
通讯作者：
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