The trichloroacetic acid-soluble radioactivity released during incubation of mouse liver particles containing intravenously injected formaldehyde-treated (131)I-albumin consisted almost entirely of (131)I-iodotyrosine. The material was shown to be excreted into the medium and was not due to disruption of the particles by acid. Triton X-100 or the absence of sucrose in the medium inhibited hydro...

Cell ghosts were obtained from Candida utilis and Saccharomyces cerevisiae by the action of some conformational isomers of pancreatic ribonuclease which passed through the cell wall and penetrated the cell membrane. In the interior, the enzyme caused extensive disorganization of the cellular structure as evidenced by the results of vital staining and electron microscopy. Ribonucleic acid was de...

When isolated spinach chloroplasts are illuminated, photosynthesis and CO(2) fixation die off within 30 to 90 minutes. Even when air levels of CO(2) are used which maintain high and rate-saturating amounts of ribulose 1,5-bisphosphate inside the plastids, CO(2) fixation declines. The decline begins with a drop in activity of the ribulose 1,5-bishosphate carboxylase/oxygenase, specifically loss ...

Electron micrographs of a purified succinate and DPNH oxidase system prepared from heart muscle reveal that it has a vesicular appearance and is membranous in nature. In keeping with its vesicular appearance is the fact that light scattering by this preparation shows marked changes as the molarity of the suspending medium is altered. Treatment of this preparation with 0.5 per cent deoxycholate ...

1. The relationship of sucrose and water concentration to invertase activity in vivo and in vitro has been studied under the same environmental conditions. 2. The sucroclastic activity of S. cerevisiae cells and of invertase solutions prepared from them reacts to changes in sucrose and water concentration in an identical manner. 3. The invertase contained in living yeast cells is just as freely...

Whole cell deformability of red cells was measured as a continuous function of suspending medium osmolality using the ektacytometer, a laser-diffraction viscometer. Study of normal cells in which water content and membrane surface area had been selectively modified showed that this technique can detect changes in these properties with high sensitivity. The osmotic deformability profiles obtaine...

1. The addition of blood serum displaces the optimum for agglutination of red blood cells in a salt-free medium to the reaction characteristic of flocculation of the serum euglobulin. 2. This effect is not due merely to a mechanical entanglement of the cells by the precipitating euglobulin, since at reactions at which the latter is soluble it protects the cells from the agglutination which occu...