Yusuke T. Maeda

We found that Dictyostelium cells in both vegetative and starved states commonly organize their own shape into three ordered patterns, elongation, rotation, and oscillation, in the absence of external stimuli. Further, cells inactivated for PI3-kinase (PI3K) and/or PTEN did not show ordered patterns due to the lack of spatial control in pseudopodial formation in both the vegetative and starved states. We also found that spontaneous polarization was achieved in starved cells by asymmetric localiz

The physical interaction between the cytoskeleton and the cell membrane is essential in defining the morphology of living organisms. In this study, we use a synthetic approach to polymerize bacterial MreB filaments inside phospholipid vesicles. When the proteins MreB and MreC are expressed inside the liposomes, the MreB cytoskeleton structure develops at the inner membrane. Furthermore, when purified MreB is used inside the liposomes, MreB filaments form a 4-10 μm rigid bundle structure and defo

Thermophoresis, the Soret effect, depletes a high concentration of a polyethylene glycol polymer solution from the hot region and builds a concentration gradient. In such a solution, solutes of small concentration experience thermophoresis and polyethylene glycol concentration-dependent restoring forces. We report that by using focused laser heating and varying the polyethylene glycol concentration one observes geometrical localizations of solutes like DNA and RNA into patterns such as a ring. F

In thermophoresis, with the fluid at rest, suspensions move along a gradient of temperature. In an aqueous solution, a PEG polymer suspension is depleted from the hot region and builds a concentration gradient. In this gradient, DNA polymers of different sizes can be separated. In this work the effect of the polymer structure for genomic DNA and small RNA is studied. For genome-size DNA, individual single T4 DNA is visualized and tracked in a PEG solution under a temperature gradient built by in

Controlling the phases of matter is a challenge that spans from condensed materials to biological systems. Here, by imposing a geometric boundary condition, we study the controlled collective motion of Escherichia coli bacteria. A circular microwell isolates a rectified vortex from disordered vortices masked in the bulk. For a doublet of microwells, two vortices emerge but their spinning directions show transition from parallel to anti-parallel. A Vicsek-like model for confined self-propelled pa

Significance The last two decades have seen an exciting development in the field of the active turbulence of microswimmers and their control using geometric design. While being recognized as a key feature of active turbulence, collective effects in the chiral active matter have been overlooked. We shed light on the poorly understood interplay between individual chiral swimming and axisymmetric boundary conditions mediated by polar alignment by exhibiting and controlling chiral bacterial vortices

Liquid-liquid phase separation (LLPS) is important to control a wide range of reactions from gene expression to protein degradation in a cell-sized space. To bring a better understanding of the compatibility of such phase-separated structures with protein synthesis, we study emergent LLPS in a cell-free transcription-translation (TXTL) reaction. When the TXTL reaction composed of many proteins is concentrated, the uniformly mixed state becomes unstable, and membrane-less phases form spontaneousl

Topological defects in nematically aligned cell populations play a critical role in modulating collective motion, ranging from microbial colonies to epithelial tissues. Despite the potential of manipulating such topological defects to control diverse self-organized structures and collective dynamics, controlling the position of defects in active matter remains a challenging area of research. In this study, we investigated the geometry-guided control of defect positioning and alignment in a nemat

In a temperature gradient built by infrared laser heating, polyethylene glycol (PEG) of large concentration moves away from the hot region. The resulting concentration gradient of PEG creates entropic potential well and traps another solute of small concentration due to diffusiophoresis. Here we develop this method to work in two dimensional spaces and time. The steering of laser traps colloids, DNA, and living cells in designed two-dimensional patterns. By modulating laser intensity with time,

Biomolecular motor proteins that generate forces by consuming chemical energy obtained from ATP hydrolysis play pivotal roles in organizing cytoskeletal structures in living cells. An ability to control cytoskeletal structures would benefit programmable protein patterning; however, our current knowledge is limited because of the underdevelopment of engineering approaches for controlling pattern formation. Here, we demonstrate the controlling of self-assembled patterns of microtubules (MTs) drive

Epithelial cells migrate autonomously by aligning and inducing a collective motion. Controlling the collective motion of epithelial cells in geometrically confined environments is important for understanding physiological processes such as wound healing and self-organized morphogenesis. However, collective migration under a three-dimensional (3D) curved surface resembling living epithelial tissue has not yet been explored. In this study, we investigated the collective motion of a 3D-buckled poly

Saccharides are well-known to play important roles in various biological events through specific interactions with target molecules such as carbohydrate-binding proteins (so-called lectins). Although characterization and identification of lectin molecules with saccharides are essential to understand biological events, they are still difficult due to weak interactions of saccharides, especially with monosaccharides. Herein, we demonstrate enhancement and control of monosaccharide affinity toward

Gene expression via transcription-translation is the most fundamental reaction to sustain biological systems, and complex reactions occur in a small compartment of living cells. There is increasing evidence that physical effects, such as molecular crowding or excluded volume effects of transcriptional-translational machinery, affect the yield of reaction products. On the other hand, transcriptional feedback that controls gene expression during mRNA synthesis is also a vital mechanism that regula

As expressed "God made the bulk; the surface was invented by the devil" by W. Pauli, the surface has remarkable properties because broken symmetry in surface alters the material properties. In biological systems, the smallest functional and structural unit, which has a functional bulk space enclosed by a thin interface, is a cell. Cells contain inner cytosolic soup in which genetic information stored in DNA can be expressed through transcription (TX) and translation (TL). The exploration of cell