受体相互作用对细菌趋化适应速率的影响  

The effect of receptor interaction on the bacterial chemotactic adaptation rate

作　　者：任淑鉴 张驰[1] 张榕京 Shujian Ren;Chi Zhang;Rongjing Zhang(Hefei National Research Center for Physical Sciences at the Microscale,and Department of Physics,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]合肥微尺度物质科学国家研究中心,中国科学技术大学物理系,安徽合肥230026

出　　处：《中国科学技术大学学报》2023年第7期14-23,69,共11页JUSTC

基　　金：supported by the Natural Science Foundation of Anhui Province(2008085QA31).

摘　　要：生物体进化出不同的受体来感知环境中的不同刺激。受体之间的相互作用能够显著提升感知的灵敏度和适应的精度。为研究细菌趋化信号网络中不同种类受体之间的相互作用对适应速率的影响,我们使用荧光共振能量转移技术和小球标记实验系统地比较了表达混合种类受体的野生型菌株与只表达Tar受体的突变株(即,Taronly菌株)对添加不同浓度天冬氨酸的阶跃型刺激的适应时间。我们发现,在相同的饱和浓度刺激下,野生型比突变株表现出更快的适应。相比之下,在引起相同程度响应的非饱和浓度刺激下,野生型比突变株表现出更慢的适应,且这与化学受体的表达浓度无关。通过监测鞭毛马达的稳态旋转信号,我们对网络弛豫时间得出了相同的结果。通过模拟具有不同适应速率的细菌在稳定的趋化引诱剂梯度下的趋化,我们证实了不同种类受体的相互作用可以有效提高大肠杆菌在稳定的趋化引诱剂空间梯度下的趋化能力,并同时保证细胞位置分布的噪声最低。Different receptors have evolved in organisms to sense different stimuli in their surroundings.The interaction among the receptors can significantly increase sensory sensitivity and adaptation precision.To study the influence of interaction among different types of chemoreceptors on the adaptation rate in the bacterial chemotaxis signaling network,we systematically compared the adaptation time between the wild-type strain expressing mixed types of receptors and the mutant strain expressing only Tar receptors(namely,the Tar-only strain)under stepwise addition of different concentrations of L-aspartate using FRET(Förster resonance energy transfer)and bead assays.We find that the wild type exhibits faster adaptation than the mutant under the same concentration of saturated stimulus.In contrast,the wild type exhibits slower adaptation than the mutant under unsaturated stimuli that induce the same magnitude of response,and this is independent of the level of receptor expression.The same result is obtained for the network relaxation time by monitoring the steady-state rotational signal of the flagellar motors.By simulating bacterial chemotaxis with different adaptation rates in a stable gradient of chemoattractants,we confirm that the interaction of different types of receptors can effectively promote chemotaxis of Escherichia coli under a stable spatial gradient of attractants while ensuring minimum noise in the cell position distribution.

关 键 词：趋化受体 相互作用 适应速率 细菌趋化 

分 类 号：Q6-3[生物学—生物物理学]