The effect of cardiac glycoside storage on growth rate and adult size in the butterflyDanaus chrysippus (L.)

Summary Danaus chrysippus grows faster and attains significantly greater size when fed as a larva on several species of Asclepiadaceae (milkweeds) containing cardiac glycosides than on one which does not.Acknowledgment. I thank Professor D. Schneider and Dr M. Boppré for sending me a sample of butterflies of Kenya stock reared in the Federal Republic of Germany.     

Chromatin fluorescence by pyronin staining

Human, chicken and mouse cells from different tissues show a bright red-orange fluorescence of the chromatin after staining with pyronin Y. The possibility that intercalation of the dye into double helical nucleic acids accounts for this fluorescence pattern is briefly discussed.     

Sex pheromones of the armyworm moth,Spodoptera exempta (Wlk.

Zusammenfassung Es wurden mit gas-chromatographischer Elektroantennogramm-Methode (Z)-9-tetradecenyl-1-acetat und (Z)-9, (E)-12-tetradecadienyl-1-acetat als die Sexuallockstoffe weiblicherSpodoptera exempta (Wlk.) identifiziert.

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Acknowledgment: We are grateful to Mr.C. Rivers, Unit of Insect Virology, University of Oxford Field Station, for supplying insect pupae.     

Evidence that superoxide radicals are involved in the hemolytic mechanism of phenylhydrazine

Summary Phenylhydrazine produces in the red blood cell the same effect as the enzymic system xanthine oxidase-xanthine, a superoxide radical generator system. Both effects are inhibited by the enzyme superoxide dismutase.This work was supported in part by grants Nos. 1045 and 3243 of Oficina Técnica de Desarrollo Científico y Creación Artística de la Universidad de Chile.     

Antibody-dependent adherence of peritoneal cells of the rat to Trichinella spiralis larvae]

Washed peritoneal exudate cells from normal Rats firmly adhere to Trichinella spiralis larvae in the presence of serum containing anti-Trichinella antibodies. This effect is observed when muscle larvae, cells and dilutions of anti-sera are incubated for 1 hr. at 37 degrees C. No adherence takes place at 4 degrees C. Whole serum or its gammaglobulin fraction are active and effect is inhibited by the addition of Trichinella antigens. Complement is not essential since antiserum heated for 2 hrs. at 56 degrees C is active. Washed cells from infested animals do not adhere to the larvae in the absence of antiserum.     

Inhibition of fading in fluorescence microscopy of fixed cells

Summary Following Hirschfeld et al., dithionite was added to mounting media to inhibit fluorescence fading. Excellent response is reported for fluorescein, acridine orange, 33258 Hoechst, acriflavine, berberine (and ethidium bromide), but not for quinacrine.Acknowledgment. The author is grateful to Dr T. Hirschfeld of Block Engineering, Cambridge, Mass., USA, for an illuminating introduction to his work.     

Relationship between regeneration of cell surface glycoproteins in trypsin-treated chick embryo fibroblasts and cell adhesion to the substratum

Summary The ability of cells to adhere to a substratum was altered by treatment with trypsin but was restored after a 1.5-h culture. A concomitant incorporation of [³H] leucine and [⁴C] glucosamine in the trypsin-sensitive cell surface glycoproteins was observed and almost reached a plateau within 1.50 h following the treatment with trypsin.     

The influence of 6-OHDA on hypothermia produced by intrahypothalamically-injected carbachol in the pigeon

Summary The involvement of the noradrenergic system in hypothermia induced by intrahypothalamically-injected carbachol (CCh) was studied by depleting hypothalamic noradrenaline (NA) with the catecholamine neurotoxin 6-hydroxydopamine (6-OHDA) and repeating the CCh injections after 6-OHDA treatment. The results suggest that noradrenergic neurons may be involved in hypothermia produced by CCh in the pigeon.