Gas/liquid sensing via chemotaxis of Euglena cells confined in an isolated micro-aquarium

Ozasa, Kazunari; Lee, Jeesoo; Song, Simon; Hara, Masahiko; Maeda, Mizuo

doi:10.1039/c3lc50696g

Cited by 25 publications

(22 citation statements)

References 54 publications

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“…Many unicellular microorganisms as well as cell colonies are motile and orient themselves with respect to external physical and chemical parameters in their environment such as temperature (Häder et al 2014), pH, oxygen (Colombetti andDiehn 1978;Porterfield 1997), chemicals and pollutants (Govorunova and Sineshchekov 2005;Ozasa et al 2013;Azizullah et al 2014), mechanical stimuli (Mikolajczyk and Diehn 1979;Fenchel 2013), the magnetic field of the Earth (de Araujo et al 1986;Kavaliers and Ossenkopp 1994) and even electrical currents (Umrath 1959;Votta and Jahn 1972;Kim 2013). Many swimming cells orient themselves in the gravity field of the Earth using a mechanism called gravitaxis (see Chap.…”

Section: Introductionmentioning

confidence: 99%

Photomovement in Euglena

Häder

Iseki

2017

Advances in Experimental Medicine and Biology

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Motile microorganisms such as the green Euglena gracilis use a number of external stimuli to orient in their environment. They respond to light with photophobic responses, photokinesis and phototaxis, all of which can result in accumulations of the organisms in suitable habitats. The light responses operate synergistically with gravitaxis, aerotaxis and other responses. Originally the microscopically obvious stigma was thought to be the photoreceptor, but later the paraxonemal body (PAB, paraflagellar body) has been identified as the light responsive organelle, located in the trailing flagellum inside the reservoir. The stigma can aid in light direction perception by shading the PAB periodically when the cell rotates helically in lateral light, but stigmaless mutants can also orient with respect to the light direction, and negative phototaxis does not need the presence of the stigma. The PAB is composed of dichroically oriented chromoproteins which is reflected in a pronounced polarotaxis in polarized light. There was a long debate about the potential photoreceptor molecule in Euglena, including carotenoids, flavins and rhodopsins. This discussion was terminated by the unambiguous proof that the photoreceptor is a 400 kDa photoactivated adenylyl cyclase (PAC) which consists of two α- and two β-subunits each. Each subunit possesses two BLUF (Blue Light receptor Using FAD) domains binding FAD, which harvest the light energy, and two adenylyl cyclases, which produce cAMP from ATP. The cAMP has been found to activate one of the five protein kinase s found in Euglena (PK.4). This enzyme in turn is thought to phosphorylate proteins inside the flagellum which result in a change in the flagellar beating pattern and thus a course correction of the cell. The involvements of PAC and protein kinase have been confirmed by RNA interference (RNAi). PAC is responsible for step-up photophobic responses as well as positive and negative phototaxis, but not for the step-down photophobic response, even though the action spectrum of this resembles those for the other two responses. Analysis of several colorless Euglena mutants and the closely related Euglena longa (formerly Astasia longa) confirms the results. Photokinesis shows a completely different action spectrum. Some other Euglena species, such as E. sanguinea and the gliding E. mutabilis, have been investigated, again showing totally different action spectra for phototaxis and photokinesis as well as step-up and step-down photophobic responses.

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Section: Introductionmentioning

confidence: 99%

Photomovement in Euglena

Häder

Iseki

2017

Advances in Experimental Medicine and Biology

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“…1 Other organisms react to chemicals, which may serve as attractant or repellent. 2–4 This class of chemically-induced behavioral responses includes also reactions to oxygen and other gases. 5, 6 Several organisms have been found to orient with respect to the magnetic field of the Earth 7 or to thermal gradients.…”

Section: Introductionmentioning

confidence: 99%

Gravireceptors in eukaryotes—a comparison of case studies on the cellular level

et al. 2017

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We have selected five evolutionary very different biological systems ranging from unicellular protists via algae and higher plants to human cells showing responses to the gravity vector of the Earth in order to compare their graviperception mechanisms. All these systems use a mass, which may either by a heavy statolith or the whole content of the cell heavier than the surrounding medium to operate on a gravireceptor either by exerting pressure or by pulling on a cytoskeletal element. In many cases the receptor seems to be a mechanosensitive ion channel activated by the gravitational force which allows a gated ion flux across the membrane when activated. This has been identified in many systems to be a calcium current, which in turn activates subsequent elements of the sensory transduction chain, such as calmodulin, which in turn results in the activation of ubiquitous enzymes, gene expression activation or silencing. Naturally, the subsequent responses to the gravity stimulus differ widely between the systems ranging from orientational movement and directed growth to physiological reactions and adaptation to the environmental conditions.

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“…[1][2][3][4][5][6][7][8][9] Controlled swarm motion may be employed to generate flows in lab-onchip devices in conjunction with digital microfluidics, [1][2][3][4][5][10][11][12] on-chip computation as previously explored with droplet logic and neural computation, 7,13 cargo delivery, 6,[14][15][16] and for selfassembly of nano-and microdevices. 8,10,15,[17][18][19][20] Algorithms for efficient control and programming of such swarms have been extensively studied via theory 20,21 and experiment in both synthetic 22 and natural systems, from motor proteins and filaments 23,24 to single-celled organisms 2,8,25,26 to insects 27 to macroscopic robots.…”

Section: Introductionmentioning

confidence: 99%

Device and programming abstractions for spatiotemporal control of active micro-particle swarms

et al. 2017

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We present a hardware setup and a set of executable commands for spatiotemporal programming and interactive control of a swarm of self-propelled microscopic agents inside a microfluidic chip. In particular, local and global spatiotemporal light stimuli are used to direct the motion of ensembles of Euglena gracilis, a unicellular phototactic organism. We develop three levels of programming abstractions (stimulus space, swarm space, and system space) to create a scripting language for directing swarms. We then implement a multi-level proof-of-concept biotic game using these commands to demonstrate their utility. These device and programming concepts will enhance our capabilities for manipulating natural and synthetic swarms, with future applications for on-chip processing, diagnostics, education, and research on collective behaviors.

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Gas/liquid sensing via chemotaxis of Euglena cells confined in an isolated micro-aquarium

Cited by 25 publications

References 54 publications

Photomovement in Euglena

Photomovement in Euglena

Gravireceptors in eukaryotes—a comparison of case studies on the cellular level

Device and programming abstractions for spatiotemporal control of active micro-particle swarms

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