High hydrostatic pressure induces slow contraction in mouse cardiomyocytes.

Cardiomyocytes are contractile cells that regulate heart contraction. Ca flux via Ca channels activates actomyosin interactions, leading to cardiomyocyte contraction, which is modulated by physical factors (e.g.

Pressure-induced changes on the morphology and gene expression in mammalian cells.

We evaluated the effect of high hydrostatic pressure on mouse embryonic fibroblasts (MEFs) and mouse embryonic stem (ES) cells. Hydrostatic pressures of 15, 30, 60, and 90 MPa were applied for 10 min, and changes in gene expression were evaluated. Among genes related to mechanical stimuli, death-associated protein 3 was upregulated in MEF subjected to 90 MPa pressure; however, other genes known to be upregulated by mechanical stimuli did not change significantly.

Glycine insertion modulates the fluorescence properties of green fluorescent protein and its variants in their ambient environment.

The green fluorescent protein (GFP) derived from Pacific Ocean jellyfish is an essential tool in biology. GFP-solvent interactions can modulate the fluorescent property of GFP. We previously reported that glycine insertion is an effective mutation in the yellow variant of GFP, yellow fluorescent protein (YFP).

A Novel Lysophosphatidic Acid Acyltransferase of Produces Membrane Phospholipids with a -vaccenoyl Group and Is Related to Flagellar Formation.

Lysophosphatidic acid acyltransferase (LPAAT) introduces fatty acyl groups into the -2 position of membrane phospholipids (PLs). Various bacteria produce multiple LPAATs, whereas it is believed that produces only one essential LPAAT homolog, PlsC-the deletion of which is lethal. However, we found that possesses another LPAAT homolog named YihG.

High pressure inhibits signaling protein binding to the flagellar motor and bacterial chemotaxis through enhanced hydration.

High pressure below 100 MPa interferes inter-molecular interactions without causing pressure denaturation of proteins. In Escherichia coli, the binding of the chemotaxis signaling protein CheY to the flagellar motor protein FliM induces reversal of the motor rotation. Using molecular dynamics (MD) simulations and parallel cascade selection MD (PaCS-MD), we show that high pressure increases the water density in the first hydration shell of CheY and considerably induces water penetration into the CheY-FliM interface.

High hydrostatic pressure induces vigorous flagellar beating in Chlamydomonas non-motile mutants lacking the central apparatus.

The beating of eukaryotic flagella (also called cilia) depends on the sliding movements between microtubules powered by dynein. In cilia/flagella of most organisms, microtubule sliding is regulated by the internal structure of cilia comprising the central pair of microtubules (CP) and radial spokes (RS). Chlamydomonas paralyzed-flagella (pf) mutants lacking CP or RS are non-motile under physiological conditions.

Tree of motility - A proposed history of motility systems in the tree of life.

Motility often plays a decisive role in the survival of species. Five systems of motility have been studied in depth: those propelled by bacterial flagella, eukaryotic actin polymerization and the eukaryotic motor proteins myosin, kinesin and dynein. However, many organisms exhibit surprisingly diverse motilities, and advances in genomics, molecular biology and imaging have showed that those motilities have inherently independent mechanisms.

Increased hydrostatic pressure induces nuclear translocation of DAF-16/FOXO in C. elegans.

Mechanical stimulation is well known to be important for maintaining tissue and organ homeostasis. Here, we found that hydrostatic pressure induced nuclear translocation of a forkhead box O (FOXO) transcription factor DAF-16, in C. elegans within minutes, whereas the removal of this pressure resulted in immediate export of DAF-16 to the cytoplasm.

Molecular dynamics simulation of proteins under high pressure: Structure, function and thermodynamics.

Background: Molecular dynamics (MD) simulation is well-recognized as a powerful tool to investigate protein structure, function, and thermodynamics. MD simulation is also used to investigate high pressure effects on proteins. For conducting better MD simulation under high pressure, the main issues to be addressed are: (i) protein force fields and water models were originally developed to reproduce experimental properties obtained at ambient pressure; and (ii) the timescale to observe the pressure effect is often much longer than that of conventional MD simulations.

Commonly stabilized cytochromes c from deep-sea Shewanella and Pseudomonas.

Two cytochromes c (SBcytc and SVcytc) have been derived from Shewanella living in the deep-sea, which is a high pressure environment, so it could be that these proteins are more stable at high pressure than at atmospheric pressure, 0.1 MPa. This study, however, revealed that SBcytc and SVcytc were more stable at 0.

Morphological Control of Microtubule-Encapsulating Giant Vesicles by Changing Hydrostatic Pressure.

For the development of artificial cell-like machinery, liposomes encapsulating cytoskeletons have drawn much recent attention. However, there has been no report showing isothermally reversible morphological changes of liposomes containing cytoskeletons. We succeeded in reversibly changing the shape of cell-sized giant vesicles by controlling the polymerization/depolymerization state of cytoskeletal microtubules that were encapsulated in the vesicles using pressure changes.

High-pressure microscopy for tracking dynamic properties of molecular machines.

High-pressure microscopy is one of the powerful techniques to visualize the effects of hydrostatic pressures on research targets. It could be used for monitoring the pressure-induced changes in the structure and function of molecular machines in vitro and in vivo. This review focuses on the dynamic properties of the assemblies and machines, analyzed by means of high-pressure microscopy measurement.

Tracking the Movement of a Single Prokaryotic Cell in Extreme Environmental Conditions.

Many bacterial species move toward favorable habitats. The flagellum is one of the most important machines required for the motility in solution and is conserved across a wide range of bacteria. The motility machinery is thought to function efficiently with a similar mechanism in a variety of environmental conditions, as many cells with similar machineries have been isolated from harsh environments.

Reversible Morphological Control of Tubulin-Encapsulating Giant Liposomes by Hydrostatic Pressure.

Liposomes encapsulating cytoskeletons have drawn much recent attention to develop an artificial cell-like chemical-machinery; however, as far as we know, there has been no report showing isothermally reversible morphological changes of liposomes containing cytoskeletons because the sets of various regulatory factors, that is, their interacting proteins, are required to control the state of every reaction system of cytoskeletons. Here we focused on hydrostatic pressure to control the polymerization state of microtubules (MTs) within cell-sized giant liposomes (diameters ∼10 μm). MT is the cytoskeleton formed by the polymerization of tubulin, and cytoskeletal systems consisting of MTs are very dynamic and play many important roles in living cells, such as the morphogenesis of nerve cells and formation of the spindle apparatus during mitosis.

Sodium-driven energy conversion for flagellar rotation of the earliest divergent hyperthermophilic bacterium.

Aquifex aeolicus is a hyperthermophilic, hydrogen-oxidizing and carbon-fixing bacterium that can grow at temperatures up to 95 °C. A. aeolicus has an almost complete set of flagellar genes that are conserved in bacteria.

High-Pressure Microscopy for Studying Molecular Motors.

Movement is a fundamental characteristic of all living things. This biogenic function is carried out by various nanometer-sized molecular machines. Molecular motor is a typical molecular machinery in which the characteristic features of proteins are integrated; these include enzymatic activity, energy conversion, molecular recognition and self-assembly.

Single-molecule analysis of the rotation of F₁-ATPase under high hydrostatic pressure.

F1-ATPase is the water-soluble part of ATP synthase and is an ATP-driven rotary molecular motor that rotates the rotary shaft against the surrounding stator ring, hydrolyzing ATP. Although the mechanochemical coupling mechanism of F1-ATPase has been well studied, the molecular details of individual reaction steps remain unclear. In this study, we conducted a single-molecule rotation assay of F1 from thermophilic bacteria under various pressures from 0.

Glycine insertion makes yellow fluorescent protein sensitive to hydrostatic pressure.

Fluorescent protein-based indicators for intracellular environment conditions such as pH and ion concentrations are commonly used to study the status and dynamics of living cells. Despite being an important factor in many biological processes, the development of an indicator for the physicochemical state of water, such as pressure, viscosity and temperature, however, has been neglected. We here found a novel mutation that dramatically enhances the pressure dependency of the yellow fluorescent protein (YFP) by inserting several glycines into it.

High hydrostatic pressure induces counterclockwise to clockwise reversals of the Escherichia coli flagellar motor.

The bacterial flagellar motor is a reversible rotary machine that rotates a left-handed helical filament, allowing bacteria to swim toward a more favorable environment. The direction of rotation reverses from counterclockwise (CCW) to clockwise (CW), and vice versa, in response to input from the chemotaxis signaling circuit. CW rotation is normally caused by binding of the phosphorylated response regulator CheY (CheY-P), and strains lacking CheY are typically locked in CCW rotation.

Bacterial motility measured by a miniature chamber for high-pressure microscopy.

Hydrostatic pressure is one of the physical stimuli that characterize the environment of living matter. Many microorganisms thrive under high pressure and may even physically or geochemically require this extreme environmental condition. In contrast, application of pressure is detrimental to most life on Earth; especially to living organisms under ambient pressure conditions.

Microscopic analysis of bacterial motility at high pressure.

The bacterial flagellar motor is a molecular machine that converts an ion flux to the rotation of a helical flagellar filament. Counterclockwise rotation of the filaments allows them to join in a bundle and propel the cell forward. Loss of motility can be caused by environmental factors such as temperature, pH, and solvation.

Resonance acoustic microbalance with naked-embedded quartz (RAMNE-Q) biosensor fabricated by microelectromechanical-system process.

A resonance acoustic microbalance with a naked-embedded quartz (RAMNE-Q) is realized by a microfabrication method, aiming at broader applications of quartz-crystal microbalance (QCM) biosensors. The RAMNE-Q biosensor consists of three layers; a silicon layer with an engraved microchannel and sandwiching glass layers. The naked AT-cut quartz resonator of 9.

Replacement-free mass-amplified sandwich assay with 180-MHz electrodeless quartz-crystal microbalance biosensor.

This study describes a sensitivity-amplified detection method in a replacement-free electrodeless quartz-crystal microbalance (QCM) biosensor. A sandwich assay is proposed for detecting C-reactive proteins (CRP), where the biotinated second anti-CRP antibody is weighted by streptavidin for sensitivity amplification. Because the first CRP antibody was immobilized nonspecifically on naked quartz surfaces, the sandwich assay was repeated using the same sensor chip, making possible the replacement-free assay.