The ability of calcium loaded heavy sarcoplasmic reticulum vesicles to specifically respond to the addition of various agents such as caffeine, calcium ions and calmodulin antagonists to rapidly released calcium can largely be diminished by passing the vesicular suspension it 0.3 M sucrose, 0.6 M KCl, 4 mM CaCl2, pH 7.0 through a Sepharose 6B column or by centrifuging it through a sucrose gradi...

DNA-dependent RNA polymerase I was purified from the mouse myeloma, MOPC 315. The enzyme was solubilized from purified nucleoli and subjected to chromatography on CM-Sephadex, DEAE-Sephadex, and phosphocellulose ion exchange resins and to sedimentation in sucrose gradients. These procedures yielded a chromatographically homogeneous enzyme which was purified almost lO,OOO-fold with respect to wh...

The genomic RNA of hepatitis C virus (HCV) in the plasma of volunteer blood donors was detected by using the polymerase chain reaction in a fraction of density 1.08 g/ml from sucrose density gradient equilibrium centrifugation. When the fraction was treated with the detergent NP40 and recentrifuged in sucrose, the HCV RNA banded at 1.25 g/ml. Assuming that NP40 removed a lipid-rich surface coat...

The present study evaluates the effects of 5-fluorouracil (FUra) on the structure of newly synthesized DNA purified from bone marrow cells. DNA synthesis was decreased by 30 and 45% of control in the presence of 19 and 100 microM FUra, respectively. Furthermore at these concentrations of FUra, the DNA strand sizes were smaller as determined by alkaline sucrose gradients. Enzymatic digestion of ...

Trichosporon cutaneum is shown to utilize six disaccharides, cellobiose, maltose, lactose, sucrose, melibiose, and trehalose. T. cutaneum can thus be counted with the rather restricted group of yeasts (11 to 12% of all investigated) which can utilize lactose and melibiose. The half-saturation constants for uptake were 10 +/- 3 mM sucrose or lactose and 5 +/- 1 mM maltose, which is of the same o...

A procedure is described for the isolation of enzymatically active nuclei from chick embryo liver. It consists of the homogenization of the pooled tissue in 0.32 M sucrose-3 mM MgCl(2) followed by a slow centrifugation. The resulting nuclear pellet is then purified further in a discontinuous density gradient composed of sucrose solutions containing Mg(2+) ions, the lower portion of the gradient...

1. Synaptosomes Kiebler et al [1] was the first group to describe the use of a discontinuous iodixanol gradient in the isolation of dendritic spines from mouse hippocampus. The gradient comprised four layers of 9%, 12.5%, 15% and 25% (w/v) iodixanol (equivalent to densities of 1.076, 1.095, 1.105 and 1.152 g/ml); the densest solution contained the material pelleted from the hippocampal homogena...

Vacuoles were prepared from endosperm tissue of 4-day-old castor bean seedlings (Ricinus communis var. Hale) and purified on a stepped sucrose gradient. It was shown by assays of marker enzymes that there was only trace contamination of the final preparation by other organelles (mitochondria, glyoxysomes, nuclei, spherosomes, and plastids) and by cytoplasmic components. Hydrolytic enzymes (acid...

Human polymorphonuclear leucocytes were homogenized in isotonic sucrose and subjected to analytical subcellular fractionation by centrifugation on a discontinuous sucrose density gradient to produce a phosphasome-enriched fraction, contaminated primarily by plasma membrane. Experiments to separate these membrane fractions by centrifugation on gradients of Nycodenz or Percoll, or by toroidal coi...

A novel technique for partial separation of amylose and amylopectin using zonal ultracentrifugation is introduced, supported by analytical ultracentrifuge measurements. Starch was first solubilised in 90% DMSO and 5% sucrose and then layered onto a gradient forming solution of 10–30% sucrose in 90% DMSO, with a cushion made up of 36% caesium chloride and 25% sucrose in water. Solutions were the...