Isolation of single motile cells using a high-speed picoliter pipette

2019 ◽  
Vol 23 (2) ◽  
Author(s):  
Yusuke Kasai ◽  
Shinya Sakuma ◽  
Fumihito Arai
Keyword(s):  
High Speed ◽  
Motile Cells

scholarly journals Control of helical navigation by three-dimensional flagellar beating

2020 ◽  
Author(s):  
Dario Cortese ◽  
Kirsty Y. Wan
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Rotation ◽  
Live Cells ◽  
High Speed Imaging ◽  
Flagellar Beat ◽  
Motile Cells ◽  
Beat Pattern ◽  
Swimming Trajectories ◽  
Realistic Geometries

Helical swimming is a ubiquitous strategy for motile cells to generate self-gradients for environmental sensing. The model biflagellate Chlamydomonas reinhardtii rotates at a constant 1 – 2 Hz as it swims, but the mechanism is unclear. Here, we show unequivocally that the rolling motion derives from a persistent, non-planar flagellar beat pattern. This is revealed by high-speed imaging and micromanipulation of live cells. We construct a fully-3D model to relate flagellar beating directly to the free-swimming trajectories. For realistic geometries, the model reproduces both the sense and magnitude of the axial rotation of live cells. We show that helical swimming requires further symmetry-breaking between the two flagella. These functional differences underlie all tactic responses, particularly phototaxis. We propose a control strategy by which cells steer towards or away from light by modulating the sign of biflagellar dominance.

Microrobotic visual control of motile cells using high-speed tracking system

2005 ◽  
Vol 21 (4) ◽  
pp. 704-712 ◽  
Author(s):  
N. Ogawa ◽  
H. Oku ◽  
K. Hashimoto ◽  
M. Ishikawa
Keyword(s):  
High Speed ◽  
Tracking System ◽  
Visual Control ◽  
Speed Tracking ◽  
Motile Cells

scholarly journals Leading edge stability in motile cells is an emergent property of branched actin network growth

2020 ◽  
Author(s):  
Rikki M. Garner ◽  
Julie A. Theriot
Keyword(s):  
High Speed ◽  
Noise Suppression ◽  
Animal Cell ◽  
Leading Edge ◽  
Lateral Spreading ◽  
Actin Network ◽  
Biological Noise ◽  
Network Growth ◽  
Motile Cells ◽  
Branch Formation

AbstractAnimal cell migration is predominantly driven by the coordinated, yet stochastic, polymerization of thousands of nanometer-scale actin filaments across micron-scale cell leading edges. It remains unclear how such inherently noisy processes generate robust cellular behavior. We employed high-speed, high-resolution imaging of migrating neutrophil-like HL-60 cells to explore the fine-scale dynamic shape fluctuations that emerge and relax throughout the process of leading edge maintenance. We then developed a minimal stochastic model of the leading edge that is able to reproduce this stable relaxation behavior. Remarkably, we find that lamellipodial stability naturally emerges from the interplay between branched actin network growth and leading edge shape – with no additional feedback required – based on a synergy between membrane-proximal branching and lateral spreading of filaments. These results thus demonstrate a novel biological noise-suppression mechanism based entirely on system geometry. Furthermore, our model suggests that the Arp2/3-mediated ∼70-80º branching angle optimally smooths lamellipodial shape, addressing its long-mysterious conservation from protists to mammals.One sentence summaryAn experimental and computational investigation of fluctuation dynamics at the leading edge of motile cells demonstrates that the specific angular geometry of Arp2/3-mediated actin network branch formation lies at the core of a successful biological noise-suppression strategy.

scholarly journals A New Framework for Microrobotic Control of Motile Cells based on High-Speed 3-D Tracking and Galvanotaxis Control

2008 ◽  
Vol 26 (6) ◽  
pp. 575-582
Author(s):  
Takeshi Hasegawa ◽  
Naoko Ogawa ◽  
Hiromasa Oku ◽  
Masatoshi Ishikawa
Keyword(s):  
High Speed ◽  
Motile Cells ◽  
New Framework

scholarly journals Single Nanoparticle Tracking Reveals Efficient Long-Distance Undercurrent Transport above Swarming Bacteria

2019 ◽  
Author(s):  
Jingjing Feng ◽  
Zexin Zhang ◽  
Xiaodong Wen ◽  
Jianfeng Xue ◽  
Yan He
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Fluid Phase ◽  
Population Level ◽  
Long Distance ◽  
Motile Cells ◽  
Large Step ◽  
Complex Fluid ◽  
Non Gaussian

AbstractFlagellated bacteria move collectively in a swirling pattern on agar surfaces immersed in a thin layer of viscous “swarm fluid”, but the role of this fluid in mediating the cooperation of the bacterial population is not well understood. Herein, we use gold nanorods (AuNRs) as single particle tracers to explore the spatiotemporal structure of the swarm fluid. We observed that individual AuNRs are transported in a plane of ~2 μm above the motile cells. They can travel for long distances (>700 μm) in a 2D plane at high speed (often >50 μm2/s) without interferences from bacterial movements. The particles are apparently lifted up and transported by collective mixing of the small vortices around bacteria during localized clustering and de-clustering of the motile cells, exhibiting superdiffusive and non-Gaussian characteristics with alternating large-step jumps and confined lingering. Their motions are consistent with the Lévy walk (LW) model, revealing efficient transport flows above swarms. These flows provide obstacle-free highways for long-range material transportations, shed light on how swarming bacteria perform population-level communications, and reveal the essential role of the fluid phase on the emergence of large-scale synergy. This approach is promising for probing complex fluid dynamics and transports in other collective systems.

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

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