Miles Yamanaka

Vaccination against the cat flea Ctenocephalides felis felis.

Non‐chemical control of haematophagous parasites is a desirable goal. We report here on the use of concealed antigens from the major digestive organ of the cat‐flea as vaccine components. Rabbits were immunized with various antigens from cat flea midguts, and immunoglobulin from these rabbits was fed to cat fleas in an artifical feeding system. Antibody produced against soluble antigens from the midguts of fed fleas was able to kill fleas in this system. Dogs were then immunized with various antigen preparations, and challenged for a week with live fleas. Significantly fewer live fleas were recovered from dogs immunized with fed midgut supernatant, and recovered live female fleas produced significantly fewer eggs. This study indicates the possibility of vaccination as a means of control of flea, and possibly other blood sucking insect populations.

Analysis of the polypeptides synthesized in rinderpest virus-infected cells

We have identified, by [35S]methionine labeling, eight major induced proteins and a number of minor proteins in rinderpest virus-infected bovine kidney cells. The polypeptides ranged in molecular weight from 212 to 21.5 kDa. The majority of these polypeptides are virus specific, as demonstrated by immunoprecipitation with rabbit hyperimmune serum against rinderpest. Infected cells radiolabeled with glucosamine contained a 75-kDa polypeptide and a broad band migrating at 80 kDa, both identified as virus specific by immunoprecipitation. Phosphorylated virus-specific proteins of 65 kDa and a complex of polypeptides at 92.5 kDa were also identified. Monospecific and monoclonal antibodies against measles virus and canine distemper virus hemagglutinin, fusion protein, nucleocapsid protein, and phosphoproteins confirmed the identity of the corresponding rinderpest virus-specific polypeptides.

A calcium/calmodulin-dependent cyclic adenosine monophosphate phosphodiesterase from Drosophila heads

A Ca2+-activated cycl AMP phosphodiesterase from Drosophila melanogaster heads was studied. The enzyme accounted for approx. 40% of the total, soluble cyclic AMP phosphodiesterase activity in heads. After gel filtration, Ca2+ stimulation of the enzyme was no longer apparent, but Ca2+ activation could be restored by the addition of boiled Drosophila extract to the column-fractionated phosphodiesterase. The protein responsible for restoring Ca2+ activation was purified and shown to have some characteristics of calmodulin. In addition, porcine calmodulin was able to activate the Drosophila phosphodiesterase. Thus, the phosphodiesterase-calmodulin system in Drosophila appears analogous to similar systems in mammals.

Sexual dimorphism and electrophoretic variation in the form I cyclic nucleotide phosphodiesterase from Drosophila melanogaster

We have investigated the form I cyclic nucleotide phosphodiesterase (PDE) from Drosophila melanogaster and shown that whereas heads and male thoraces and abdomens contain high levels of Ca2+-stimulated enzyme, female thoraces and abdomens contain little Ca2+-stimulated activity. The electrophoretic patterns of form I PDE from these 3 sources have also been studied and reveal that heads, and male thoraces and abdomens, produce two bands of form I PDE both of which are stimulated by Ca2+. Extracts of female thoraces and abdomens, on the other hand, show only a single, faster running band of PDE activity which is only marginally stimulated by Ca2+, if at all. Surveying wild-type strains of Drosophila has revealed that one strain, Swedish, shows altered electrophoretic mobility of the PDE band from female thoraces and abdomens. The alteration is such that the Swedish PDE band runs more anodally than the Oregon-R and Canton-S PDE activities. Mixing experiments, using co-homogenization of heads with female thoraces and abdomens, yield a single faster running band on electrophoresis. This band contains only Ca2+-insensitive PDE. Attempts to reconstruct this loss of Ca2+-sensitive PDE without electrophoresis have failed. The Swedish electrophoretic variation of the PDE from female thoraces and abdomens has been found to be recessive with respect to the Canton-S phenotype, but the variation is observed to re-emerge and segregate with the third chromosome in the F2 generation. The results indicate that electrophoretic variation in the form I PDE is, by itself, insufficient to allow the location of the structural gene for this enzyme.