Motile bacteria possess a stimulus-response system in which the input is the local concentration of an attractant or repellent and the output is the motion of the cell. It is known that some chemicals, e.g., sugars and amino acids, are sensed by specific receptors and that changes in receptor occupancy lead to changes in flagellar rotational bias (the probability that the flagella spin counterclockwise), but the way in which the receptors are coupled to the flagella remains obscure. We will continue our studies of the physiology of this system by examining the rotational behavior of tethered cells of Escherichia coli exposed to step and impulse stimuli. From responses of genetically engineered strains containing modified tar (aspartate receptor) and tsr (serine receptor) proteins, we expect to learn how information about receptor occupancy crosses the cytoplasmic membrane and how different receptor classes interact. From the responses of flagellar markers on filamentous cells stimulated at different points along their length, we will determine the physical properties of the substance that carries information from the receptors to the flagella. We should be able to determine its diffusion coefficient and its size. By tracking and tethering cells from the same culture and comparing their swimming and rotational behavior, we expect to learn more about synchronization of different flagella in the same cell. This work complements that on genetics and biochemistry pursued in other laboratories. The long-range goal is an understanding at the molecular level of basic processes involved in receptor function and sensory transduction.
| Shrivastava, Abhishek; Patel, Visha K; Tang, Yisha et al. (2018) Cargo transport shapes the spatial organization of a microbial community. Proc Natl Acad Sci U S A 115:8633-8638 |
| Turner, Linda; Berg, Howard C (2018) Labeling Bacterial Flagella with Fluorescent Dyes. Methods Mol Biol 1729:71-76 |
| Hosu, Basarab G; Berg, Howard C (2018) CW and CCW Conformations of the E. coli Flagellar Motor C-Ring Evaluated by Fluorescence Anisotropy. Biophys J 114:641-649 |
| Ko, William; Lim, Sookkyung; Lee, Wanho et al. (2017) Modeling polymorphic transformation of rotating bacterial flagella in a viscous fluid. Phys Rev E 95:063106 |
| Hughes, Kelly T; Berg, Howard C (2017) The bacterium has landed. Science 358:446-447 |
| Berg, Howard C (2017) The flagellar motor adapts, optimizing bacterial behavior. Protein Sci 26:1249-1251 |
| Turner, Linda; Ping, Liam; Neubauer, Marianna et al. (2016) Visualizing Flagella while Tracking Bacteria. Biophys J 111:630-639 |
| Hosu, Basarab G; Nathan, Vedavalli S J; Berg, Howard C (2016) Internal and external components of the bacterial flagellar motor rotate as a unit. Proc Natl Acad Sci U S A 113:4783-7 |
| Shrivastava, Abhishek; Roland, Thibault; Berg, Howard C (2016) The Screw-Like Movement of a Gliding Bacterium Is Powered by Spiral Motion of Cell-Surface Adhesins. Biophys J 111:1008-13 |
| Lele, Pushkar P; Roland, Thibault; Shrivastava, Abhishek et al. (2016) The flagellar motor of Caulobacter crescentus generates more torque when a cell swims backward. Nat Phys 12:175-178 |
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