Conversion of beating mode inChlamydomonas flagella induced by electric stimulation

Yoshimura, Kenjiro; Shingyoji, Chikako; Takahashi, K.

doi:10.1002/(sici)1097-0169(1997)36:3<236::aid-cm4>3.0.co;2-5

Cited by 32 publications

(20 citation statements)

References 40 publications

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“…2). All but one of these stroke kinematics have been observed experimentally in living organisms (8,(10)(11)(12)(13). In particular, the qualitative agreement between our computed optimal undulatory and breaststrokes A, D, E, and experimentally recorded images is striking (Fig.…”

Section: Discussionsupporting

confidence: 70%

“…The beating patterns of biflagellated phytoplankon have been investigated experimentally in the context of flagellar synchronization and the motile response to chemical and light signals (8,(10)(11)(12)(13). Recent experimental work demonstrated the effective exploitation of microscale resource patches by marine microorganisms (2) and by phytoplankton in particular (23).…”

Section: Discussionmentioning

confidence: 99%

“…The most common stroke, the breaststroke, has the same effective recovery structure as the stroke of cilia. The other stroke, observed in response to a shock of light (12) or an electric stimulation (13), resembles the undulatory beating patterns of uniflagellates. Here, we elucidate the relevance of these two different beating modes and rationalize their function by computing optimal stroke patterns for biflagellated organisms.…”

mentioning

confidence: 85%

“…A remarkable feature of Chlamydomonas is that its flagella are observed to beat in both the effective recovery stroke (10,11) and the undulatory traveling wave (12,13). The most common stroke, the breaststroke, has the same effective recovery structure as the stroke of cilia.…”

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confidence: 99%

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Optimal feeding and swimming gaits of biflagellated organisms

Tam

Hosoi

2011

Proc. Natl. Acad. Sci. U.S.A.

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Locomotion is widely observed in life at micrometric scales and is exhibited by many eukaryotic unicellular organisms. Motility of such organisms can be achieved through periodic deformations of a tail-like projection called the eukaryotic flagellum. Although the mechanism allowing the flagellum to deform is largely understood, questions related to the functional significance of the observed beating patterns remain unresolved. Here, we focus our attention on the stroke patterns of biflagellated phytoplanktons resembling the green alga Chlamydomonas. Such organisms have been widely observed to beat their flagella in two different ways-a breaststroke and an undulatory stroke-both of which are prototypical of general beating patterns observed in eukaryotes. We develop a general optimization procedure to determine the existence of optimal swimming gaits and investigate their functional significance with respect to locomotion and nutrient uptake. Both the undulatory and the breaststroke represent local optima for efficient swimming. With respect to the generation of feeding currents, we found the breaststroke to be optimal and to enhance nutrient uptake significantly, particularly when the organism is immersed in a gradient of nutrients.optimization | stroke kinematics | low Reynolds number | efficiency T he vast majority of living organisms are found in an astonishing diversity at micrometric scales. Such seemingly simple unicellular organisms interact with their surroundings and exhibit complex dynamic behaviors in order to access resource-rich environments. The ability to locate and take advantage of such favorable environments relies on a rapid chemotactic response (1, 2). In this paper, we investigate the motility of specific microorganisms to address questions related to the functional adaptation, efficiency, and optimization of biolocomotion.A dominant trait shared by many microorganisms is the prevalence of flagella as motility appendages. The structure of the axoneme, which constitutes the core of the eukaryotic flagellum, is extremely well preserved across the eukaryotic domain. This same structure is found to propel sperm cells and, when several of them beat collectively as cilia, to expel mucus from human lungs. The eukaryotic flagellum has a complex internal "9 þ 2" microtubule structure (3), whose elaborate molecular machinery allows the flagellum to induce local bending moments and actively deform its shape. It is noteworthy that these flagella are widely observed to beat in two significantly different ways: undulatory traveling waves that propagate down the flagellum (as exhibited by sperm cells), and so-called "effective recovery" strokes commonly observed in cilia. Because it is possible for organisms to alter and control the waveform along the flagellum, it is of interest to investigate the functional significance of these specific flagellar stroke patterns and their utility with respect to swimming and feeding.Previous investigations of nutrient transport and hydrodynamics around microorganisms (4...

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Section: Discussionsupporting

confidence: 70%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 85%

mentioning

confidence: 99%

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Optimal feeding and swimming gaits of biflagellated organisms

Tam

Hosoi

2011

Proc. Natl. Acad. Sci. U.S.A.

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“…One conventional method of performing such observations is to use an optical microscope combined with a high-speed camera [6][7][8][9] . For a detailed and in-depth analysis of the motions, observation from various angles is useful.…”

Section: Introductionmentioning

confidence: 99%

Controllable alignment of elongated microorganisms in 3D microspace using electrofluidic devices manufactured by hybrid femtosecond laser microfabrication

Kawano

Liu

et al. 2017

Microsyst Nanoeng

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This paper presents a simple technique to fabricate new electrofluidic devices for the three-dimensional (3D) manipulation of microorganisms by hybrid subtractive and additive femtosecond (fs) laser microfabrication (fs laser-assisted wet etching of glass followed by water-assisted fs laser modification combined with electroless metal plating). The technique enables the formation of patterned metal electrodes in arbitrary regions in closed glass microfluidic channels, which can spatially and temporally control the direction of electric fields in 3D microfluidic environments. The fabricated electrofluidic devices were applied to nanoaquariums to demonstrate the 3D electro-orientation of Euglena gracilis (an elongated unicellular microorganism) in microfluidics with high controllability and reliability. In particular, swimming Euglena cells can be oriented along the z-direction (perpendicular to the device surface) using electrodes with square outlines formed at the top and bottom of the channel, which is quite useful for observing the motions of cells parallel to their swimming directions. Specifically, z-directional electric field control ensured efficient observation of manipulated cells on the front side (45 cells were captured in a minute in an imaging area of~160 × 120 μm), resulting in a reduction of the average time required to capture the images of five Euglena cells swimming continuously along the z-direction by a factor of~43 compared with the case of no electric field. In addition, the combination of the electrofluidic devices and dynamic imaging enabled observation of the flagella of Euglena cells, revealing that the swimming direction of each Euglena cell under the electric field application was determined by the initial body angle.

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