A possible biomimetic synthesis of fluoroacetic acid

Summary We propose that fluoroacetate may be formed in plants by fluorodecarboxylation of malonic acid.     

Offset rate of action of muscarinic antagonists depends on their structural flexibility.

Time course measurements of the action of muscarinic antagonists were performed in the spontaneously beating carp atrium. Several high affinity drugs, which embody the quinuclidine structure were examined. The structural flexibility of these molecules was reflected in the dissociation of the drugs from the muscarinic receptor. The dissociation of rigid drugs was very much prolonged as compared to flexible drugs of the same affinity.     

In vitro biosynthesis of juvenile hormone III by the corpora allata ofCalliphora vomitoria and its role in ovarian maturation and sexual receptivity

Summary JH III is the only JH detected by GLC-MS in medium from in vitro incubations of corpora allata of adult females ofCalliphora vomitoria. When corpora allata were removed from females at various times during the reproductive cycle and the JH III produced by the glands in vitro measured by a JH III radioimmunoassay, an increase in the level of synthesis was found to occur before previtellogenesis (0–24 h). A second increase appeared at the onset of vitellogenesis (72–83 h) and continued until the end of vitellogenesis (96 h) and the occurrence of chorionation (120 h). Since sexual receptivity develops with vitellogenesis, the significantly higher levels of JH III biosynthesis in vitro at this time supports a possible role for JH in the acquisitive of receptivity.     

Metabolically regulated cyclical contractures in microinjectedSpirostomum: A pharmacological study

Summary Spirostomum was treated extracellularly and intracellularly with a range of metabolites to investigate the intracellular regulation of cyclic calcium movements. The results indicate, close links between calcium movements and mitochondrial metabolism.We are grateful to Dr.A. Gaudemar, Institut de Chimie des Substances Naturelle, Gif-sur-Yvette, France for a gift of bongkrekic acid, to Dr.D. C. Aldridge, Biochemistry Dept., I. C. I. Ltd., Macclesfield, U. K. for a gift of avenceolide and toE. M. Ettienne for many hours of discussion. Dr.R. B. Hawkes is a Visiting Research Fellow at the Hebrew University of Jerusalem.     

Enzymatic characterization of nine endoparasite species of small ermine moths (Yponomeutidae)

Summary Eight hymenopterous and 1 dipterous species, all endoparasitic in eggs, larvae, or pupae of small ermine moths (Yponomeuta) were investigated for their allozyme variation at 3–29 loci. The mean heterozygosity level of the hymenopterous species is one-third of that of the dipterous species. Zymogram patterns of the parasite larvae do not interfere with those of the host.