Silva Kalinga Pavan T, Chellamuthu Prithiviraj, Boedicker James Q
Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, United States of America.
Department of Biological Sciences, University of Southern California, Los Angeles, CA, United States of America.
PLoS Comput Biol. 2017 Oct 19;13(10):e1005809. doi: 10.1371/journal.pcbi.1005809. eCollection 2017 Oct.
In multispecies microbial communities, the exchange of signals such as acyl-homoserine lactones (AHL) enables communication within and between species of Gram-negative bacteria. This process, commonly known as quorum sensing, aids in the regulation of genes crucial for the survival of species within heterogeneous populations of microbes. Although signal exchange was studied extensively in well-mixed environments, less is known about the consequences of crosstalk in spatially distributed mixtures of species. Here, signaling dynamics were measured in a spatially distributed system containing multiple strains utilizing homologous signaling systems. Crosstalk between strains containing the lux, las and rhl AHL-receptor circuits was quantified. In a distributed population of microbes, the impact of community composition on spatio-temporal dynamics was characterized and compared to simulation results using a modified reaction-diffusion model. After introducing a single term to account for crosstalk between each pair of signals, the model was able to reproduce the activation patterns observed in experiments. We quantified the robustness of signal propagation in the presence of interacting signals, finding that signaling dynamics are largely robust to interference. The ability of several wild isolates to participate in AHL-mediated signaling was investigated, revealing distinct signatures of crosstalk for each species. Our results present a route to characterize crosstalk between species and predict systems-level signaling dynamics in multispecies communities.
在多物种微生物群落中，诸如酰基高丝氨酸内酯（AHL）等信号的交换能够实现革兰氏阴性菌物种内部以及不同物种之间的通讯。这一过程，通常被称为群体感应，有助于调控对于微生物异质群体中物种生存至关重要的基因。尽管信号交换在充分混合的环境中得到了广泛研究，但对于物种空间分布混合物中串扰的后果却知之甚少。在此，我们在一个包含利用同源信号系统的多个菌株的空间分布系统中测量了信号动态。对含有lux、las和rhl AHL受体回路的菌株之间的串扰进行了量化。在微生物的分布式群体中，表征了群落组成对时空动态的影响，并与使用修正反应扩散模型的模拟结果进行了比较。在引入一个单一术语以解释每对信号之间的串扰后，该模型能够重现实验中观察到的激活模式。我们量化了在存在相互作用信号的情况下信号传播的稳健性，发现信号动态在很大程度上对干扰具有稳健性。研究了几种野生分离株参与AHL介导信号传导的能力，揭示了每个物种独特的串扰特征。我们的结果提供了一条表征物种间串扰并预测多物种群落中系统水平信号动态的途径。
