Rapid purification of mouse L cell interferon labeled with radioactive amino acid by immune precipitation

Mouse L cell interferon induced by Newcastle disease virus was labeled with [³H]methionine added to the culture during its active synthesis, and precipitated quantitatively from the culture fluid using anti-interferon serum which had been raised against partially purified interferon and extensively absorbed with impurities. The material recovered from the precipitate showed, upon polyacrylamide gel electrophoresis in the presence and in the absence of sodium dodecyl sulfate, only two major radioactive peaks coinciding with the two interferon species, S (40,000 daltons) and F (24,000 daltons). Rapid purification of radiolabeled interferon was thus possible. Based on the methionine incorporation data, the interferon protein was estimated to represent 0.12% of all the protein synthesized by the cells, and 0.57% of all the protein synthesized and secreted to the culture fluid, during the labeling period (7 to 20 hr after infection).     

Bidirectional effects of splenectomy on the growth of syngeneic tumor in mice

The effects of splenectomy on tumor growth following inoculation with a relatively large number of cells (1×10⁷) and a smaller number of cells (5×10⁵) of Meth I tumor were studied. When 1×10⁷ tumor cells were inoculated, tumor growth in splenectomized mice was depressed, while tumor in sham-operated mice grew progressively. On the contrary, when 5×10⁵ tumor cells were inoculated, the tumor take was lower in sham-operated than in splenectomized mice. The spleen cells from mice inoculated with either a large or small number of tumor cells, showed an equally potent cytotoxic activity, but no detectable suppressor cell activity. On the other hand, the activity of immunosuppressive factor was detected in sera from mice inoculated with 1×10⁷ tumor cells, but not in those given 5×10⁵ cells. The effect of splenectomy on tumor growth is, thus, bidirectional, depending on the dose of tumor cells inoculated.     

Telencephalic and preoptic areas integrate sexual behavior in hime salmon (landlocked red salmon, Oncorhynchus nerka): results of electrical brain stimulation experiments

Various patterns of sexual behavior were evoked in freely swimming hime salmon by electrical stimulation of specific loci in the telencephalon and the preoptic area (POA) using chronically implanted electrodes. Furthermore, co-ordinated sexual behavior corresponding to stages of the natural spawning sequence was elicited from some of these brain regions. These results suggest that (1) sexual behavior is integrated in specific parts of the telencephalon and POA, and (2) within these regions there is a hierarchy of neural systems which mediate progressively more complete components of normal sexual behavior.