<i>Escherichia coli</i>
            Remodels the Chemotaxis Pathway for Swarming

Partridge, Jonathan D.; Nhu, Nguyen T. Q.; Dufour, Y.; Harshey, Rasika M.

doi:10.1128/mbio.00316-19

Cited by 45 publications

(64 citation statements)

References 77 publications

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“…Additionally, it would enable dynamic controls in processes for which the use of chemical inducers is prohibitively expensive. Beyond chemical and recombinant protein production, IPTG induction has been used for a variety of research applications, including to study persistence 50 , bacterial motility and swarming 51 , inducible protein degradation 52 , biofilm formation 53 , and biomaterials 54 . Furthermore, the lac operon has been exported to other bacteria for IPTG inducibility 55–60 .…”

Section: Discussionmentioning

confidence: 99%

Optogeneticlacoperon to control chemical and protein production inEscherichia coliwith light

Lalwani

Carrasco-López

et al. 2019

Preprint

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23Control of the lac operon with IPTG has been used for decades to regulate gene expression in E. 24 coli for countless applications, including metabolic engineering and recombinant protein 25 production. However, optogenetics offers unique capabilities such as easy tunability, 26 reversibility, dynamic induction strength, and spatial control that are difficult to obtain with 27 chemical inducers. We developed an optogenetic lac operon in a series of circuits we call 28OptoLAC. With these circuits, we control gene expression from various IPTG-inducible 29 promoters using only blue light. Applying them to metabolic engineering improves mevalonate 30 and isobutanol production by 24% and 27% respectively, compared to IPTG induction, controlled fermentations scalable to at least 2L bioreactors. Furthermore, OptoLAC circuits 32 enable light control of recombinant protein production, reaching yields comparable to IPTG 33 induction, but with enhanced tunability of expression and spatial control. OptoLAC circuits are 34 potentially useful to confer light controls over other cell functions originally engineered to be 35 . 36 37 38 39 40 41 42 43 44 45 a preferred host for many biotechnological applications, including metabolic engineering for 48 chemical production and expression of recombinant proteins. The vast wealth of knowledge on 49 the physiology, genetics, and metabolism of this bacterium, as well as the abundance of 50 molecular tools for its genetic manipulation, have made E. coli an organism of choice across the 51 spectrum of metabolic engineering, from proofs of principle 1 to the development of large-scale 52 industrial processes 2-5 . However, metabolic engineering in E. coli still faces important 53 challenges, especially considering that each pathway presents distinct obstacles, which may be 54 addressed with technological improvements. 55 IPTG-inducible 56A key challenge in metabolic engineering is the need for dynamic control 6 . This need commonly 57 arises when the biosynthesis of the product of interest competes with cell growth, or when the 58 product of interest, or its precursors, are toxic to the host organism, leading to growth inhibition 59 and poor productivity. These challenges are usually addressed by dividing fermentations into a 60 growth phase (in which the biosynthetic pathway of interest is repressed and metabolism is 61 devoted to growing biomass) and a production phase (in which the pathway of interest is 62 chemically induced, frequently at the expense of cell growth). However, pathway productivities 63 can be greatly impacted by the timing, rates, and levels of induction, which can be difficult to 64 control with chemical inducers. We recently showed that light can be an effective alternative to 65 chemicals as an inducing agent for metabolic engineering in S. cerevisiae, enhancing the 66 dynamic control over fermentations by adding tunability, reversibility, and independence from 67 4 medium composition 7 . To achieve this, we devised optogenetic circuits that harn...

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Section: Discussionmentioning

confidence: 99%

Optogeneticlacoperon to control chemical and protein production inEscherichia coliwith light

Lalwani

Carrasco-López

et al. 2019

Preprint

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“…The foundation of microbial chemotactic response mechanism is based on E. coli that are extensively studied [48,49]. The chemotactic repertoire of E. coli is quite simple.…”

Section: Chemotaxis Systemmentioning

confidence: 99%

Bacterial chemotaxis: a way forward to aromatic compounds biodegradation

2020

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Worldwide industrial development has released hazardous polycyclic aromatic compounds into the environment. These pollutants need to be removed to improve the quality of the environment. Chemotaxis mechanism has increased the bioavailability of these hydrophobic compounds to microorganisms. The mechanism, however, is poorly understood at the ligand and chemoreceptor interface. Literature is unable to furnish a compiled review of already published data on up-to-date research on molecular aspects of chemotaxis mechanism, ligand and receptor-binding mechanism, and downstream signaling machinery. Moreover, chemotaxis-linked biodegradation of aromatic compounds is required to understand the chemotaxis role in biodegradation better. To fill this knowledge gap, the current review is an attempt to cover PAHs occurrence, chemical composition, and potential posed risks to humankind. The review will cover the aspects of microbial signaling mechanism, the structural diversity of methyl-accepting chemotaxis proteins at the molecular level, discuss chemotaxis mechanism role in biodegradation of aromatic compounds in model bacterial genera, and finally conclude with the potential of bacterial chemotaxis for aromatics biodegradation.

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“…The field of view was ~0.9 mm square containing on average 200 to 600 cells. Cell trajectories were reconstructed using a custom MATLAB (Mathworks) code (github.com/dufourya/SwimTracker) (2,3). Behavioral parameters such as speed and tumble bias, were extracted from single-cell trajectories as previously described (2).…”

Section: Time-lapse Microscopy Cell Tracking and Trajectory Analysismentioning

confidence: 99%

“…Cell trajectories were reconstructed using a custom MATLAB (Mathworks) code (github.com/dufourya/SwimTracker) (2,3). Behavioral parameters such as speed and tumble bias, were extracted from single-cell trajectories as previously described (2). The swimming speed was calculated by taking the average velocity of individual cells over their respective trajectories excluding the frames where cells are predicted to be tumbling.…”

Section: Time-lapse Microscopy Cell Tracking and Trajectory Analysismentioning

confidence: 99%

“…S1, right), which abolished the circular motion. B. subtilis makes a similar surfactant(2), so 117 we used a srfA mutant deficient in surfactin synthesis. P. aeruginosa motility in liquid differs 118 from the run-tumble pattern, and is instead characterized as a run-reverse-turn pattern, where 119 prolonged runs are interrupted by a reversal and 'flick' to cause a change in direction (24).…”

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confidence: 99%

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Remodeling of Chemotaxis is a Cornerstone of Bacterial Swarming

Partridge

Nguyen

Dufour

et al. 2020

Preprint

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21Many bacteria use flagella-driven motility to swarm or move collectively over a surface terrain. 22 Bacterial adaptations for swarming can include cell elongation, hyper-flagellation, recruitment of 23 special stator proteins and surfactant secretion, among others. We recently demonstrated another 24 swarming adaptation in Escherichia coli, wherein the chemotaxis pathway is remodeled to increase 25 run durations (decrease tumble bias), with running speeds increased as well. We show here that 26 the modification of motility parameters during swarming is not unique to E. coli, but shared by a 27 diverse group of bacteria we examined -Proteus mirabilis, Serratia marcescens, Salmonella 28 enterica, Bacillus subtilis, and Pseudomonas aeruginosa -suggesting that altering the 29 chemosensory physiology is a cornerstone of swarming. 30 31 32 33 34 35 36 37 38 39 40 41 42 Importance 43 Bacteria within a swarm move characteristically in packs, displaying an intricate swirling motion 44 where hundreds of dynamic packs continuously form and dissociate as the swarm colonizes 45 increasing expanse of territory. The demonstrated property of E. coli to reduce its tumble bias and 46 hence increase its run duration during swarming is expected to maintain/promote side-by-side 47 alignment and cohesion within the bacterial packs. Here we observe a similar low tumble bias in 48 five different bacterial species, both Gram positive and Gram negative, each inhabiting a unique 49 habitat and posing unique problems to our health. The unanimous display of an altered run-tumble 50 bias in swarms of all species examined here suggests that this behavioral adaptation is crucial for 51 swarming.52 53 54 55 56 57 58 59 60 61 62 63 65 flagella (1-3). A wide array of phenotypic adaptations are associated with swarming. A common 66 attribute of all swarms is a pattern of ceaseless circling motion, in which packs of cells all traveling 67 in the same directions split and merge, with continuous exchange of bacteria between the packs 68 (3-5). This behavior differs from movement of the bacteria in bulk liquid, where they swim 69 individually (6). In E. coli, the mechanics of flagella are similar during both swimming and 70 swarming in that peritrichous flagella driven by bi-directional rotary motors switch between 71 counterclockwise (CCW) and clockwise (CW) directions. However, while CCW rotation promotes 72 formation of a coherent flagellar bundle that propels the cell forward (run) during both swimming 73 and swarming, a transient switch in rotational direction (CW) causes the cell to tumble while 74swimming, but reverse direction while swarming (7,8). 75The switching frequency of the flagellar motor is controlled by the chemotaxis system, best 76 studied in E. coli, where transmembrane receptors detect extracellular signals and transmit them 77 via phosphorelay to the motor, to promote migration to favorable locales during swimming (9). 78The ability to perform chemotaxis is not essential for swarming, but a basal tumble bias is 79 important ...

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Escherichia coli Remodels the Chemotaxis Pathway for Swarming

Cited by 45 publications

References 77 publications

Optogeneticlacoperon to control chemical and protein production inEscherichia coliwith light

Optogeneticlacoperon to control chemical and protein production inEscherichia coliwith light

Bacterial chemotaxis: a way forward to aromatic compounds biodegradation

Remodeling of Chemotaxis is a Cornerstone of Bacterial Swarming

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