The respiratory control of rat liver mitochondria is lost when they are subjected to rate zonal centrifu~ation in a sucrose gradient (8.0% to 46.6%, w/w) at values for r t necessary for resolution. High sucrose concentrat ion and high ~ 2 t are bo th responsible. Respiratory control can be maintained in iso-osmotic Ficoll + 8.3% sucrose media, and after zonal centrifugation in such media at val...

Small ciliate protozoa of the genus Uronema were separated from labeled bacteria by means of a discontinuous sucrose gradient. More than 98% of the radioactivity associated with the bacteria was found in the upper portion of the gradient, whereas the remaining portion of the gradient contained the ciliates.

Pig oocytes were hand collected after follicular puncture or were mass harvested with stainless-steel screens and purified on sucrose density gradients. Most oocytes obtained by mass harvesting with a 75 micron screen and selecting on a 0 and 30% discontinuous sucrose gradient were meiotically incompetent and atretic after culture. Two enriched populations of oocytes were isolated from the 0-15...

The alterations of subcellular metabolite levels during the day in spinach leaves have been investigated using nonaqueous density gradient centrifugation to separate chloroplasts, cytosol, and vacuole. The results provide direct evidence for the role of sucrose phosphate synthase and cytosolic fructose 1,6-bisphosphatase in regulating sucrose synthesis in leaves and also show that the phosphate...

SUMMARY DNA extracted from frog virus 3 has a GC mol fraction of about 0"56. The mol. wt. of the DNA is about Ioo x I@ (97 × IO 6 by neutral sucrose gradient sedimentation; IO2 × IO 6 from renaturation kinetics). Analysis by neutral sucrose sedimentation indicated that the DNA exists as a single heteroduplex in the virus particle. Alkaline sucrose gradient sedimentation indicated that single st...