Actively growing Escherichia coli cells respond to increased osmotic pressure by increasing their internal pools of K+ (Epstein & Schultz, 1965) and of the amino acids glutamate, proline and a-aminobutyric acid (Britten & McClure, 1962; Measures, 1975). The change in amino acid pools may be brought about either by increased rates of their synthesis or by stimulation of the rate of their uptake....

Two theories have been proposed to explain how high positive pressures are developed in sugar maple stems when temperatures fluctuate around freezing. The Milburn-O'Malley theory proposes that pressure development is purely physical and does not require living cells or sucrose. The osmotic theory invokes the involvement of living cells and sucrose to generate an osmotic pressure difference betw...

STARLING (1894, 1896) described the basic forces responsible for producing fluid shifts between the circulating blood and the surrounding tissue spaces. On page 324 of his classical article entitled "On the absorption of fluids from the connective tissue spaces," Starling described how capillary pressure determines transudation into the tissues and the osmotic pressure of the proteins determine...

A common test for the presence of toxic organic substances in plant tissues, and therefore of the potential role of antibiosis (specifically allelopathy) in native plant cozmmunities, has been to apply a water extract of the tissues in germination tests of cultivated annuals. The observed osmotic pressure of the extracts can be high, and sucrose solutions of similar osmotic pressure result in a...

BACKGROUND Therapeutic hypothermia is neuroprotective in asphyxiated neonates by counteracting mechanisms contributing to brain injury. Although an initial increased permeability is part of an inflammatory reaction and thereby a natural healing process, an excessive endothelial permeability with edema formation may result in impaired hemodynamics. Reduced permeability may, however, benefit heal...

Osmosis is usually taught from the point of view of the osmotic pressure developed when solutions of different concentrations of solute are separated by an ideal semipermeable membrane. The osmotic pressure is defined at equilibrium when there is no net flow, and it takes some time to reach this equilibrium. Although the osmotic pressure is certainly important, teaching only this point of view ...

The water relations of pepper plants (Capsicum frutescens L.) under conditions conducive to guttation were studied to evaluate the control of plant water stress with polyethylene glycols. The addition of polyethylene glycol 6000 to the nutrient solution resulted in water relations similar to those expected in soil at the same water potentials. Specifically, xylem pressure potential in the root ...

This study explored the association between stress-induced hemoconcentration and plasma colloid osmotic pressure, hemodynamic reactivity, and microvascular permeability during a protracted stress task in 26 healthy, young participants. Microvascular permeability was measured during rest using venous congestion plethysmography in a subsample of 13 participants. The task increased hematocrit, col...

The forces between charged macromolecules, usually given in terms of osmotic pressure, are highly affected by the intervening ionic solution. While in most theoretical studies the solution is treated as a homogeneous structureless dielectric medium, recent experimental studies concluded that, for a bathing solution composed of two solvents (binary mixture), the osmotic pressure between charged ...