Physiological heterogeneities in microbial populations and implications for physical stress tolerance.
Physiological heterogeneities in microbial populations and implications for physical stress tolerance.
复制标题
DOI：
10.1186/1475-2859-11-94
复制
发表时间：
2012-07-16
影响因子：
6.4
通讯作者：
Lantz AE
中科院分区：
文献类型：
--
作者：
Carlquist M;Fernandes RL;Helmark S;Heins AL;Lundin L;Sørensen SJ;Gernaey KV;Lantz AE
传统上，在分析微生物细胞培养时会考虑整个种群的平均值。然而，生物反应器中典型的微生物种群在大多数可在单细胞水平上测量的表型上是异质的。有迹象表明，这种异质性一方面可能是不利的(降低产量和生产率)，但另一方面也是有益的(有助于快速适应新的条件--即增加发酵过程的稳健性)。因此，了解和控制微生物种群的异质性对于改进微生物细胞工厂工艺具有重要意义。在这项工作中，开发了一个双报告系统，并应用于在混合良好的生物反应器中好氧培养过程中芽殖酵母种群内生长和细胞适合度的异质性。该报告菌株基于核糖体蛋白RPL22a启动子控制下的绿色荧光蛋白(GFP)的表达，使根据荧光强度水平区分细胞生长时相成为可能。此外，通过利用细胞内GFP水平和细胞膜完整性的强相关性，可以区分细胞膜坚固性高和低的亚群，从而有能力抵御冻融胁迫。观察到生长和细胞膜稳健性之间存在强烈的负相关，这进一步支持了细胞资源有限的假设，需要在生长和稳健性两个功能之间进行权衡分配。此外，种群内的权衡是不同的，并且可以区分两个不同的亚群在这两种拮抗的细胞操作模式之间转移的发生。该报告菌株能够在细胞培养的不同阶段定位群体生长的异质性和细胞膜对冻融胁迫的稳健性。所描述的报告系统是了解环境条件对微生物细胞群体异质性的影响，从而理解细胞在类似工业过程的条件下的反应的有价值的工具。它可能被应用于识别更健壮的亚群，并为更有效的生物处理开发新的菌种改良和工艺设计策略。
Traditionally average values of the whole population are considered when analysing microbial cell cultivations. However, a typical microbial population in a bioreactor is heterogeneous in most phenotypes measurable at a single-cell level. There are indications that such heterogeneity may be unfavourable on the one hand (reduces yields and productivities), but also beneficial on the other hand (facilitates quick adaptation to new conditions - i.e. increases the robustness of the fermentation process). Understanding and control of microbial population heterogeneity is thus of major importance for improving microbial cell factory processes. In this work, a dual reporter system was developed and applied to map growth and cell fitness heterogeneities within budding yeast populations during aerobic cultivation in well-mixed bioreactors. The reporter strain, which was based on the expression of green fluorescent protein (GFP) under the control of the ribosomal protein RPL22a promoter, made it possible to distinguish cell growth phases by the level of fluorescence intensity. Furthermore, by exploiting the strong correlation of intracellular GFP level and cell membrane integrity it was possible to distinguish subpopulations with high and low cell membrane robustness and hence ability to withstand freeze-thaw stress. A strong inverse correlation between growth and cell membrane robustness was observed, which further supports the hypothesis that cellular resources are limited and need to be distributed as a trade-off between two functions: growth and robustness. In addition, the trade-off was shown to vary within the population, and the occurrence of two distinct subpopulations shifting between these two antagonistic modes of cell operation could be distinguished. The reporter strain enabled mapping of population heterogeneities in growth and cell membrane robustness towards freeze-thaw stress at different phases of cell cultivation. The described reporter system is a valuable tool for understanding the effect of environmental conditions on population heterogeneity of microbial cells and thereby to understand cell responses during industrial process-like conditions. It may be applied to identify more robust subpopulations, and for developing novel strategies for strain improvement and process design for more effective bioprocessing.
登录
查看更多内容
影响因子：
4.1
作者：
Enfors, SO;Jahic, M;Manelius, Å
通讯作者：
Manelius, Å
新型克隆载体的构建和特性分析 2. 多用途克隆系统
影响因子：
3.5
作者：
BOLIVAR, F;RODRIGUEZ, RL;FALKOW, S
通讯作者：
FALKOW, S
影响因子：
6.4
作者：
Delvigne F;Boxus M;Ingels S;Thonart P
通讯作者：
Thonart P
影响因子：
6.4
作者：
Ferrer-Miralles N;Domingo-Espín J;Corchero JL;Vázquez E;Villaverde A
通讯作者：
Villaverde A
影响因子：
4.7
作者：
Delvigne, Frank;Brognaux, Alison;Thonart, Philippe
通讯作者：
Thonart, Philippe