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Tests made to study protein changes related to post-mortem tenderization of meat, using 3 to 12 month old chickens aged at 0°C under aseptic conditions showed that buffer extractable nitrogen decreased rapidly during the onset of rigor, and then increased gradually to a maximum value during post-rigor aging. Changes in extractable nitrogen occurred mainly as a result of changes in the extractability of actomyosin. The amino acid and peptide content of the meat increased slightly but continuously during post rigor aging. The water-holding capacity of stromamyofibrillar proteins isolated as a single fraction was substantially less during rigor than post rigor. Differences in the rate of post-mortem tenderization between breast and leg muscle, as well as between birds of different ages, appear to be related to differences in stroma protein content of muscle. Specific proteolysis seems to weaken or break the bonds which are formed between actin and the matrix of the muscle during the onset of rigor, causing an increase in the extractability of actomyosin and water-holding capacity of the myofibrillar proteins.

Summary Fractionation of a horse serum to the globulins of rabbit serum by means of alcohol at low temperatures and low ionic strengths leads to separation of the antibody in a single fraction. Changes in the characteristics of the antibody are noted and discussed on the basis of the previous study of fractionation with salt and precipitation by water, and in the light of other studies on the effect of the removal of lipides.

Analyses by paper electrophoresis showed three protein fractions present in all stages of development except the egg, where only a single fraction was recovered. The fraction with the second greatest mobility was the most variable during the insect's development, always reaching a peak of concentration at and around times of molting, and disappearing between molts; it disappeared in adult males after 3 to 4 weeks and in adult females after 10 days. The first and third fractions showed variability that could be associated with development, but less strikingly. Fraction 3 also was present in greater proportion in adult females than in adult males.

The recovery of free amino compounds from potato liquor simulating starch processing water was carried out in the laboratory on a much larger scale than previously reported. The solids content of the liquor charged to the column was about 3% compared with only 1% before; this, together with a larger size column meant much faster charging of the column with amino compounds. The combined middle fractions of the eluate from the column contained 14% solids and the most concentrated single fraction 27% solids. Demonstration of the possibility of obtaining most of the amino compounds content in fractions of such high concentrations seems to form a basis for pilot plant studies looking forward to recovery of these compounds from potato starch processing water.

A study was made of the strength of compacts from single-fraction iron and rock salt powders under dynamic and static loads. It has been demonstrated that the mechanism of rupture of compacts from iron and rock salt powders is apparently identical, so that the nature of the chemical bond in the material determines only the absolute value of strength of compacts.

8x3 + 28x2+28x+17 _ a3 a2 (x+2)3.(x-l)2 ~0 -2)3+( +2)2 I Al I &2 1 fri |"(x+2)i'(x-l)ai"(x-l)" There are two standard techniques for evaluating the coefficients. One technique consists of recombining the partial-fraction expansion into a single fraction and equating like powers of its numerator polynomial with those of the numerator polynomial of the original frac tion. If the number of undetermined coeffi cients is ft, there would be linearly in dependent equations in unknowns. These could be solved to find any of the coeffi cients. In the above example, the following would have to be solved

Oocytes of Rana pipiens were incubated in 22Na-Ringer's solution and 22Na-23Na exchange in the nucleus and cytoplasm followed by low-temperature microdissection. Cytoplasmic sodium consists of 2 kinetic fractions: the larger (88%) slowly exchanging (t½ ∼ 2 days), and the smaller (12%) rapidly exchanging (t½ ∼ 53 min). Nuclear sodium consists of a single fraction whose concentration is similar and whose rate constant is identical with that of the rapidly exchanging cytoplasmic fraction. Our findings are consistent with a model of compartmentalization in which rapidly exchanging sodium is nearly uniformly distributed in the water of the nucleus and cytoplasm and its exchange limited by movement through the cell surface. On the other hand, slowly exchanging sodium is restricted to the cytoplasm, sorbed to or sequestered in some as yet unidentified cytoplasmic constituent. To whom requests for reprints should be sent.

Summary1. Serum from untreated timothy sensitive patient (E.F.) was fractionated by Sephadex G-200 gel-filtration and DEAE-cellulose ion-exchange chromatography, and resulted in the isolation of a single fraction with reagin activity. 2. The isolated reagin possesses chromatographic and immunochemi-cal characteristics of γG-globulin.

Methods for the preparation of cell fractions from homogenates of the posterior pituitary glands of rabbits are described. By controlling the speed of centrifugation it was possible to isolate 80% of the oxytocin and vasopressin in a sedimentable form and about half of the total hormones or two-thirds of the sedimentable hormones in a single fraction. Electron microscopy of this fraction showed that it was composed mainly of membrane-bounded granules about 1300 Å in diameter. Similar granules were found in the neural swellings of the rabbit neurohypophysis studied by electron microscopy. The possibility that vasopressin and oxytocin are stored in different granules is discussed.