Alvin S. Levine

Avian reticuloendotheliosis virus (strain T). IV. Infectivity and transmissibility in day-old cockerels.

SUMMARY In day-old cockerels all routes of inoculation (intracranial, intramuscular, intracardiac, intranasal, intraperitoneal, subcutaneous, and via the alimentary canal) were capable of inducing deaths from reticuloendotheliosis virus (REV). From 15 moribund cockerels sampled individually, infectious REV was obtained from oral-nasal washings, gut washings, feather-shaft follicle tips, and skin containing feather follicles, but not from feather dander. Antibody to REV was detected in the serum of contact cagemates. None of the normal control birds, housed separately in the same room, were serologically positive. In spite of the presence of infectious virus in moribund birds and the serologic conversion of the contact mates, horizontal transmission of the disease symptoms was not demonstrated. The results suggest that close contact is required for horizontal transmission of the virus, and that contact with REV in this manner either fails to produce disease or produces a subclinical form.

Fine structure of the Rauscher leukemia virus as revealed by incubation in snake venom.

Abstract Purified Rauscher leukemia virus was incubated in reconstituted lyophilized snake venom. Examination of the negatively stained venom-treated virus preparations showed the outer envelopes of most of the particles to be ruptured, revealing capsids the circumference of which showed 25–30 capsomeres 100 A in length and 75–80 A in width. Prolonged incubation in venom resulted in modification of the capsids of most of the particles and revealed a shell or framework penetrated with holes arranged in a hexagonal array. These results suggest that the capsids of Rauscher leukemia virus are covered with a coat of material which is removed by incubation in snake venom.

Incorporation of labeled precursors into lipids of tumors induced by rous sarcoma virus

Abstract 1. 1. A comparison was made of the lipids in the chorioallantoic membranes of chicken eggs and in tumors induced in the membranes by Rous sarcoma virus. 2. 2. Thin-layer chromatography of the lipids from the two tissues revealed only minor differences in their compositions. 3. 3. Measurements were made of the incorporation of several labeled precursors into the lipids of the two tissues. From a buffered salt medium containing glucose, the greatest incorporation of radioactivity was found in the triglycerides. This was true for both tissues and for either glucose or acetate as the radioactive precursor. The tumor slices incorporated about six times as much radioactivity as did the normal membranes. Much of the increased incorporation took place in the triglycerides, but there appeared to be an increased incorporation by the tumors in almost all of the lipid fractions tested. There was considerable incorporation into the glycerol portion of the triglycerides from glucose and even from pyruvate. 4. 4. The difference in incorporation by the two tissues appeared to be largely a matter of amount rather than of distribution.

Suppression of Rauscher virus-induced leukemia by L-asparaginase

Abstract Murine leukemia induced by Rauscher virus was shown to be responsive to L-asparaginase from E. coli . When administered in small multiple doses, asparaginase suppressed splenomegaly and prolonged survival, in the absence of a concomitant inhibition of viremia. Asparagine treatment partially suppressed the leukemic process, and failed to block the antileukemic effect of asparaginase.

Reticuloendotheliosis virus (strain T). VI. An immunogen versus reticuloendotheliosis and Rous sarcoma.

Avian reticuloendotheliosis virus (REV), also known as the Twiehaus agent or T-virus, was isolated from an adult turkey with leukosis-like lesions by Twiehaus and Robinson in 1958 (12). The pathology associated with REV infection is reticular and lymphoid tumors in the liver, spleen, and other viscera, and occasional enlargement of the peripheral nerves in turkeys, chickens, and quail (5,7,13). REV has also been demonstrated to be infectious for a wide variety of avian species, including chickens, Japanese quail, pheasant, turkeys, and ducks (11). REV has been defined in our laboratory as having the following properties: 1) a C-type virus with a diameter of approximately 80 nm (8); 2) a buoyant density of 1.16-1.18 g/cc in continuous sucrose gradients (2); 3) a genome consisting of single-stranded RNA (2,8) ; 4) ether-sensitivity (4); 5) rapid inactivation outside

Palmitate and glucose metabolism in tumors induced by Rous sarcoma virus

Abstract 1. 1. A study was made of the relationship between palmitate and glucose metabolism in tumors induced by Rous sarcoma virus in the chorioallantoic membranes of embryonated chicken eggs. A comparison also was made with the corresponding metabolism of the normal membranes. 2. 2. Glucose depressed palmitate oxidation in the tumors but had little effect in the normal membranes. At the same time the glucose increased palmitate uptake by the tumors and gave a smaller increase by the normal membranes. Incorporation of palmitate into the lipids of the tissues was increased by the addition of glucose. The increase was considerably greater in the tumors than in the normal tissue. 3. 3. Palmitate increased glucose uptake, oxidation and incorporation into lipids in both tissues. These effects of palmitate on glucose utilization were less marked than those of glucose on palmitate utilization. 4. 4. Hydrolysis of the tissue lipids revealed that palmitate increased glucose incorporation into the water-soluble portion of the hydrolyzate and glucose increased palmitate incorporation into the fatty acid portion.

Metabolic pathways of the host cell important in the replication of Rous sarcoma virus in vitro

Abstract Metabolic pathways essential for RSV multiplication in chicken embryo fibroblasts were studied using glycolytic and oxidative inhibitors. Both glycolytic and oxidative processes of the host cell were found essential for RSV replication. In addition, it appears that glucose may serve as an energy source for RSV replication in vitro .