Enzymatic dephosphorylation of ovalbumin and plakalbumin

It has been shown by the work presented in this paper that it is possible to carry out a stepwise dephosphorylation of ovalbumin. With the aid of a prostate phosphatase that attacks only one of the two phosphorus-containing groups in the major component, A₁, of ovalbumin, a protein, A₂, containing 1 atom of phosphorus per mole has been prepared. Further dephosphorylation with an enzyme of intestinal origin gives a phosphorus-free ovalbumin, A₃. Plakalbumin has been similarly dephosphorylated to give P₂ and P₃. Significant changes in the electrophoretic mobility accompany each dephosphorylation step. This, together with the phosphorus content of the proteins and the crystal form, has been used to characterize and study the five modifications of ovalbumin thus produced.

The immunological demonstration of egg white in droplets and other cellular fractions of the rat kidney after intraperitoneal injection

Immunological analysis with a specific antiserum showed an increasing concentration of egg white proteins in the cortex of the kidney of the rat up to 18 hours after their intraperitoneal injection, and a fall in the following 40 hours. Homogenates of the cortical tissue prepared at 18 hours, the period of maximum droplet development, showed a large amount of the egg white proteins in the supernatant, considerable amounts in the fraction which contained the mitochondria, but the highest concentration, 6 times that of any other cell fraction, in the highly purified preparation of droplets. The relation of these findings to the morphological and histochemical evidence concerning the constitution of the droplets is discussed and the conclusion drawn that absorbed egg white proteins and mitochondrial substances are important elements in their formation.

Absence of capillary permeability response in rats to dextran and egg-white

Intradermal dextran and ovomucoid fail to increase capillary permeability in rats resistant to intraperitoneal dextran although intradermal histamine, 5-HT and compound 48/80 are as effective as in control rats. When the skin of control rats is depleted of its histamine, intradermal dextran and ovomucoid are first ineffective but later increase capillary permeability although the skin histamine remains low. Chronic treatment of control rats with intraperitoneal dextran (which only slightly reduces both the skin histamine and 5-HT) prevents the local dextran and ovomucoid responses but does not affect those of compound 48/80, histamine and 5-HT. It is concluded that intradermal dextran and ovomucoid increase capillary permeability in rats by a mechanism involving substances other than histamine and 5-HT, and that this mechanism is absent in rats which do not respond to intraperitoneal dextran.

INFLUENCE OF TEMPERATURE ON BACTERIAL INFECTION OF THE HEN'S EGG

Temperature of incubation had a marked effect on infection of eggs in which the air cells had been inoculated with a washed suspension of Serratia marcescens. There was no evidence of bacterial multiplication or spoilage in eggs held at 10 C for 42 days. Multiplication occurred in the shell membranes of eggs held at 30 or at 37 C when the yolk made contact with these membranes, and continued in the contents of the egg, at which time the first signs of spoilage appeared. In a few eggs, very large populations were present in the shell membranes and in the albumen. In eggs inoculated with Pseudomonas fluorescens and held at 10 C, bacterial multiplication occurred in the shell membranes in the first 7 days of incubation. These populations did not appear to change in size in the 7- to 14-day period of incubation. Renewed multiplication and concomitant spoilage of the contents was observed in many of the eggs thereafter.

SURVIVAL OF SHIGELLAE IN FOOD

The survival and persistence ofShigella sonneiandS. flexneriin various food preparations were studied. The length of survival and the rate of decrease in surviving fractions varied considerably depending upon the menstruum and the holding temperature. This study points out the potential hazards involved in consuming food products that may be contaminated by shigellae.

ISOLATION OF SALMONELLAE FROM FOOD SAMPLES. VI. COMPARISON OF METHODS FOR THE ISOLATION OF SALMONELLA FROM EGG PRODUCTS

THE RECOVERY OF SALMONELLAE FROM EGG PRODUCTS WAS STUDIED, BY USE OF THREE DIFFERENT ENRICHMENT PROCEDURES: (i) selenite broth, (ii) selenite broth containing 10% sterile feces, and (iii) the lactose pre-enrichment procedure. Brilliant Green Agar was used throughout as the recovery medium. Although the lactose pre-enrichment methodology promoted Salmonella recovery from samples containing small numbers of dormant organisms, the efficiency of this enrichment method is adversely affected by unfavorable coliform-Salmonella ratios. Under such conditions, early subculture of lactose broth into selenite broth is indicated. Selenite broth containing 10% sterile feces was more efficient than the lactose pre-enrichment methodology in promoting the growth of "dormant" salmonellae. Albumen adversely affected recovery of salmonellae from selenite broth, whereas whole egg and egg yolk enhanced Salmonella recovery from this medium. The selenite-feces medium presents a solution to the major problems encountered in the detection of salmonellae in egg products and offers an approach to a single medium in which food-borne salmonellae will manifest themselves with a minimum of laboratory manipulation.

INHIBITION OF THE LYMPHOCYTE RESPONSE TO INFLAMMATION WITH ANTIMETABOLITES

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