Microfluidic techniques for separation of bacterial cells via taxis

Gurung, Jyoti P; Gel, Murat; Baker, Matthew A.

doi:10.15698/mic2020.03.710

Cited by 23 publications

(15 citation statements)

References 88 publications

(118 reference statements)

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“…Despite these advances, little is known about the factors controlling zoospore behavior in porous media nor how these factors contribute to the zoospore’s preferential attraction to the root cues of host plants. In order to produce disease models demonstrating the incidence of a disease based on zoospore capability to reach a host as a function of soil composition, a major challenge will be the development of microfluidic devices to investigate zoospore displacement in conditions designed to mimic the nature, the geometry and the electric charges of soil particles [27] , [28] . Such tools would also contribute to our understanding of how zoospores sense and respond to ion stimuli, electric fields or physical obstacles.…”

Section: The Soil Environmentmentioning

confidence: 99%

Phytophthora zoospores: From perception of environmental signals to inoculum formation on the host-root surface

Bassani

Larousse

Tran

et al. 2020

Computational and Structural Biotechnology Journal

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To explore moist soils and to target host plants, phytopathogenic Phytophthora species utilize the sensory and propulsion capabilities of the biflagellate unicellular zoospores they produce. Zoospore motion and interactions with the microenvironment are of primary importance for Phytophthora physiology. These are also of critical significance for plant pathology in early infection sequential events and their regulation: the directed zoospore migration toward the host, the local aggregation and adhesion at the host penetration site. In the soil, these early events preceding the root colonization are orchestrated by guidance factors, released from the soil particles in water films, or emitted within microbiota and by host plants. This signaling network is perceived by zoospores and results in coordinated behavior and preferential localization in the rhizosphere. Recent computational and structural studies suggest that rhizospheric ion and plant metabolite sensing is a key determinant in driving zoospore motion, orientation and aggregation. To reach their target, zoospores respond to various molecular, chemical and electrical stimuli. However, it is not yet clear how these signals are generated in local soil niches and which gene functions govern the sensing and subsequent responses of zoospores. Here we review studies on the soil, microbial and host-plant factors that drive zoospore motion, as well as the adaptations governing zoospore behavior. We propose several research directions that could be explored to characterize the role of zoospore microbial ecology in disease.

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Section: The Soil Environmentmentioning

confidence: 99%

Phytophthora zoospores: From perception of environmental signals to inoculum formation on the host-root surface

Bassani

Larousse

Tran

et al. 2020

Computational and Structural Biotechnology Journal

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“…Bacterial cells can move through liquids or over moist surfaces using rotating flagella to propel themselves in response to chemical stimulus, temperature and pH ( Armitage, 2007 ; Jarrell and McBride, 2008 ; Gurung et al, 2020 ). The bacterial flagellar motor (BFM) drives the rotation of the flagellum ( Sowa and Berry, 2008 ).…”

Section: Introductionmentioning

confidence: 99%

Ancestral Sequence Reconstructions of MotB Are Proton-Motile and Require MotA for Motility

et al. 2020

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The bacterial flagellar motor (BFM) is a nanomachine that rotates the flagellum to propel many known bacteria. The BFM is powered by ion transit across the cell membrane through the stator complex, a membrane protein. Different bacteria use various ions to run their BFM, but the majority of BFMs are powered by either proton (H+) or sodium (Na+) ions. The transmembrane (TM) domain of the B-subunit of the stator complex is crucial for ion selectivity, as it forms the ion channel in complex with TM3 and TM4 of the A-subunit. In this study, we reconstructed and engineered thirteen ancestral sequences of the stator B-subunit to evaluate the functional properties and ionic power source of the stator proteins at reconstruction nodes to evaluate the potential of ancestral sequence reconstruction (ASR) methods for stator engineering and to test specific motifs previously hypothesized to be involved in ion-selectivity. We found that all thirteen of our reconstructed ancient B-subunit proteins could assemble into functional stator complexes in combination with the contemporary Escherichia coli MotA-subunit to restore motility in stator deleted E. coli strains. The flagellar rotation of the thirteen ancestral MotBs was found to be Na+ independent which suggested that the F30/Y30 residue was not significantly correlated with sodium/proton phenotype, in contrast to what we had reported previously. Additionally, four among the thirteen reconstructed B-subunits were compatible with the A-subunit of Aquifex aeolicus and able to function in a sodium-independent manner. Overall, this work demonstrates the use of ancestral reconstruction to generate novel stators and quantify which residues are correlated with which ionic power source.

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“…There exist many microfluidics device for separating and sorting motile bacteria with high precision, accuracy, and efficiency according to various taxes (6). However, many of those devices are fabricated using expensive microfabrication techniques which require sophisticated clean room facilities.…”

Section: Discussionmentioning

confidence: 99%

“…Microfluidics platforms are emerging as a technology with wide promise for microbiological research and development 5 offering precise control of flow and buffer composition at the micron scales that bacteria inhabit. Microfluidic tools are in widespread use in combination with microscopy platforms and have been applied to the study and control of gradients which influence motility, to explore the mechanisms of chemotaxis, thermotaxis, rheotaxis, magnetotaxis and phototaxis 6 . Recent developments in microfluidics technology have enabled fine separation of cells based on subtle differences in motility traits and have applications in synthetic biology 7 , directed evolution 8 and applied medical microbiology 9 .…”

Section: Introductionmentioning

confidence: 99%

“…Most of the existing work in microfluidics for separating motile bacteria has been tested on proton-powered flagellar motors, and has predominantly focused on chemotaxis 6 . Here we wanted to explore the ability to build a simple fluidics device for screening mixed populations of bacteria for those motors which are powered from novel ionic power sources besides protons.…”

Section: Introductionmentioning

confidence: 99%

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Separation and enrichment of sodium-motile bacteria using cost-effective microfluidics

Gurung

Kashani

Agarwal

et al. 2020

Preprint

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Many motile bacteria are propelled by the rotation of flagellar filaments. This rotation is driven by a membrane protein known as the stator-complex, which drives the rotor of the bacterial flagellar motor. Torque generation is powered in most cases by proton transit through the stator complex, with the next most common ionic power source being sodium. Synthetic chimeric stators which combine sodium- and proton-powered stators have enabled the interrogation of sodium-stators in species that are typically proton-powered, such as the sodium powered PomA-PotB stator complex in E. coli. Much is known about the signalling cascades that respond to attractant and govern switching bias as an end-product of chemotaxis, however less is known about how energetics and chemotaxis interact to affect the colonisation of environmental niches where ion concentrations and compositions may vary. Here we designed a fluidics system at low cost for rapid prototyping to separate motile and non-motile populations of bacteria. We measure separation efficiencies at varying ionic concentrations and confirm using fluorescence that our device can deliver eight-fold enrichment of the motile proportion of a mixed population of motile and non-motile species. Furthermore, our results show that we can select bacteria from reservoirs where sodium is not initially present. Overall, this technique can be used to implement long-term selection from liquid culture for directed evolution approaches to investigate the adaptation of motility in bacterial ecosystems.

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Microfluidic techniques for separation of bacterial cells via taxis

Cited by 23 publications

References 88 publications

Phytophthora zoospores: From perception of environmental signals to inoculum formation on the host-root surface

Phytophthora zoospores: From perception of environmental signals to inoculum formation on the host-root surface

Ancestral Sequence Reconstructions of MotB Are Proton-Motile and Require MotA for Motility

Separation and enrichment of sodium-motile bacteria using cost-effective microfluidics

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