Centrifugation fractional

Recently, two novel procedures have been described for the isolation of PHA granules based on air classification [81] or centrifugal fractionation [82] (Fig. 8). These two processes are related to the well established wet and dry milling methods used in the corn industry for the fractionation of corn seeds into endosperm, germ, and hull and for the isolation of starch grains [83]. 

The air classification method separates dry solid particles according to weight and/or size by suspension in and settling from an air stream of appropriate velocity. Centrifugal fractionation separates particles suspended in a so-... 

As with most described methods for the purification of PHA from crops, no actual experimental data are available that would allow one to evaluate the efficiency of recovery of PHA based on air classification or centrifugal fractionation and the extra costs associated with the purification of PHA particles from the PHA-rich fractions. 

Fig. 8. Flow diagram of the extraction of PHA from oilseeds using air classification or centrifugal fractionation...

The intracellular distribution of a glycosidase in a mammalian tissue can be studied by centrifugal fractionation of a homogenate made in isotonic (0.25 M) sucrose solution. The membranes of subcellular particles are preserved in this medium and, provided that there is no leakage of the enzyme, its partition between the different sizes of particle can be measured. Before the enzyme is assayed, it may be necessary to destroy the structure of the particles, in order to make the enzyme completely accessible to the substrate. 

Camphor oil is obtained by steam distillation of the wood of the camphor tree Cinnamomum camphora Sieb. (Lauraceae) growing in China, Taiwan, and Japan. The main constituent of the crude oil is camphor (ca. 50%), which can be separated by crystallization on cooling and subsequent centrifugation. Fractionation of the mother liquor gives two oils ... 

A high-speed differential centrifugal fraction for Giardia mitosomes has been generated that has been successfully used to reconstitute Fe-S cluster... 

Fractionation of the major and minor components of gum tragacanth is achieved by a variety of techniques, e.g., filtration, centrifugation, fractional precipitation, etc. In this last technique, tragacanthin disperses in 3 1 ethanolrwater, while bassorin simultaneously precipitates as a gel. Acid hydrolysis of tragacanthin yields tragacanthic acid (Belitz and Grosch, 1987). 

After centrifugation, fractionate the gradient from the bottom using tubing connected to a peristaltic pump. Carefully place the capillary tube in from the top until it reaches the bottom of the tube, then turn on the pump and collect 0.3- to 0.4-ml samples in sterile 1.5-ml microcentri-... 

How may cells be disrupted in order to obtain subcellular organelles by centrifugal fractionation ... 

Wilkins and Snell (1987) used a microtitre tray lid in an lEC rack rotor, at 600 rev./min, to centrifuge fractionated DNA from the agarose gel onto the membrane. For this purpose, gels of up to 8 X 12 cm are sandwiched between a nylon membrane and two Whatman paper sheets, all soaked in transfer buffer (e.g., 20 X SSC) and centrifuged for 20 min. 

Cortadas J., Macaya G., Bernard G. (1977) An analysis of the bovine genome by density gradient centrifugation fractionation in Cs2S04/3,6 bis (acetato-mercurimethyl) diox-ane density gradient. Eur. J. Biochem. 76 13-19. 

Centrifugal fractionation of the cell-free system showed that the enzymes which caused incorporation of glucose could be separated from the sulphate-rich material and would add glucose to the sulphate-poor component more efficiently in its absence. On re-addition of the sulphate-rich fraction, incorporation into the sulphate-poor components was slowed and some addition of glucose to sulphate-rich material could be shown. These results clearly suggest competition for a common precursor, but do not necessarily show the involvement of a single or common glycosyltransferase system, or a close relation between the two types of polymer. 

Following centrifugation, fractionate the gradient into 0 3- to 0 5-mL fractions. 

Dickenson and Fairbairn (1975), working on the ultrastructure of the alkaloidal vesicles of Papaver somniferum, found that these could be obtained in two forms the first with a smooth but progressively granulated outer membrane (Figures 6.29a and 6.29b) and the second, probably derived from the first, with adherent caplike structures which in the heavier centrifuged fractions possessed a zonally ordered interior (Figure 6.29c). 

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