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AMINOPEPTIDASE activity in starch gel electropherograms has been demonstrated indirectly and directly using a chromogenic substrate. In the indirect method the enzyme is first eluted from sections of the gel after completing the electrophoreticrun (Kowlessar et al., 1960). The enzyme activity is then measured in the eluates. In an established direct method there is visualization of enzyme activity using the chromogenic substrate, l -leucine β napthylamide (Lawrence et al., 1960). Another direct method for the demonstration of peptidase activity is based on the peroxide-forming activity of l -amino acid oxidase with the liberated amino acid (Lewis and Harris, 1967). Modifications of these two direct visualization techniques have been used in this laboratory to demonstrate aminopeptidase activity in the plasma of normal birds and birds with erythroblastosis (induced with Strain R virus). In the first method, after the runs with starch gel electrophoresis were completed, the gels were incubated in 0.1 M tris…

INTRODUCTION AVIAN erythroblastosis (Eb) is a virus-induced disease of chickens characterized by the presence of large numbers of primitive red cells in the circulating blood stream (Darcel, 1960). Preliminary studies had suggested disturbances in iron metabolism in Eb. When leukemic (Eb) blood is incubated with Fe59 there is incorporation into material with electrophoretic characteristics of fowl ferritin instead of into hemoglobin. The plasma of birds in the terminal stages of Eb shows the presence of additional plasma iron (Darcel and Bather, 1964) and it was suspected that this might also be ferritin. This paper shows that much of the iron present in Eb plasma is not bound to transferring and that it is likely present in molecules of ferritin, probably coated with a plasma protein. EXPERIMENTAL Virus: Engelbreth-Holm’s strain R virus (Eckert et al., 1956) was used to infect birds of the East Lansing Line 15 I White Leghorns.Birds were…

Many diseases in man and animals are accompanied by quantitative and qualitative changes in the plasma enzymes. A knowledge of these changes may help in the diagnosis of certain diseases and may provide useful information on their pathogenesis, Hess (1963). Wallbank et al. (1964) have reported a significant elevation of plasma lactate dehydrogenase (PLDH) in cases of avian leukosis. I have attempted to confirm this in cases of erythroblastosis induced by the Strain R erythroblastosis virus1 studied at this laboratory (Darcel and Bather, 1964), as the findings of Chelibonova-Lorer and Yakimov (1965) with this virus were in conflict with those of Wallbank. A virus inoculum which normally causes death from erythroblastosis within 10 days (Bather et al., 1963) was given intravenously to East Lansing Line 15I White Leghorns. Other birds were either given a reduced dose or were inoculated subcutaneously instead of intravenously to delay the appearance of erythroblastosis by…

IN THE terminal phases of avian erythroblastosis (Eb) the plasma α-lipoproteins are altered in a way which produces retardation and splitting of the α-lipoprotein bands on starch gel electrophoresis (Darcel, 1960; Merriman and Darcel, 1964, 1965). These changes may be duplicated by the addition of soaps and turpentines (Darcel et al., 1968), which suggested that the changes might be due to changes in the net charge of the lipoprotein micelles. One of us (Darcel, 1967) has shown by thin-layer chromatography that the Eb plasma lipoprotein contains less phosphatidyl serine and may contain less phospholipid. These alterations in the lipoprotein have prompted us to make a quantitative study of the distribution of phosphorus in the different plasma fractions in normal birds and birds with Eb in the hope that a quantitative change might be found that would help to explain the α-lipoprotein effects. MATERIALS AND METHODS All plasma samples were colleted…