Centrifugal floatation

The modified liposomes may be separated from excess protein by gel filtration using Sephadex G-75 or by centrifugal floatation in a polymer gradient (Derksen and Scherphof, 1985). 

To recover the starch, the corn kernels, for example, are pealed and then dipped in sulfuric acid at pH 3.5-4 for 40 h at 125°C. The corn kernels softened in this way are then coarsely ground and the corn nucleus removed by floatation, whereby the starch particles sedimentate. Fiber components are filtered off and the starch particles are removed from the remaining protein solution by centrifugation. The recovered starch particles are then washed and dried. Sixty percent of the starch is converted to starch syrup or dextroses by partial hydrolysis. The remaining 40% is used in the food industry or in the textile, paper, or detergent industry, partially as derivatives such as starch acetate or hydroxyethyl starch. 

When measuring mt DNA content it only has to be shown that no contamination with nuclei or nuclear fragments is present. This is conveniently achieved with appropriate gradient centrifugation or floatation techniques (Schatz et al., 1964 Neubert et al, 1968 Nass, 1969). However, because of the similar densities of mitochondria and microsomal or other cell particles a clean separation of mitochondria is seldom achieved with small amounts of material. The interpretation of the data, therefore, is greatly facilitated when the activity of a typical mitochondrial enzyme like cytochrome oxidase is given in addition to the amount of mitochondrial protein. 

Since the carbonate washing of the LDMs followed by pelleting by centrifugation yielded a pellet which was still clearly contaminated with some large soluble proteins the LDMs were purified by floatation through a sucrose layer. The sucrose density of the LDM fraction was... 

---