Sex pheromone of the pine sawflyDiprion pini (Hymenoptera: Diprionidae): Chemical identification,synthesis and biological activity

The main component of the sex pheromone secretion of femaleDiprion pini L. (Hymenoptera: Diprionidae) from insects collected both in Finland and in France has been identified as athreo-3,7-dimethyl-2-tridecanol (8 ng per female) stereoisomer by GC-MS and synthesis. The secretion also contains lower and higher homologues in small amounts (1–4% of the main component). Combined gas chromatographic-electroantennographic detection showed activity in both natural and esterified extracts (acetates and propionates); the esters of the main component gave the largest responses. The acetates and propionates of the eight stereoisomers of 3,7-dimethyl-2-tridecanol were synthesized from enantiomerically highly enriched (>99% ee) building blocks. The stereochemistry of the main component was established to be (2S,3R,7R)-3,7-dimethyl-2-tridecanol by GC analysis of the natural material. It was purified by liquid chromatography prior to the GC analysis of both its pentafluorobenzoates and its isopropylcarbamates on a non-chiral polar column (ECD) and a chiral column (NPD), respectively. Field tests demonstrated that both the acetate and propionate of the main component (100 g of each applied on cotton roll dispensers) were active in attracting males, with or without the presence of several of the minor compounds. Experiments with smaller amounts of the acetate and the propionate (1 g in France and 50 g in Finland) demonstrated that the propionate was more active than the acetate, and that it also caught more males than a blend of the two compounds.     

Nα-quinaldyl-L-arginine·HCl,a new defensive alkaloid fromSubcoccinella-24-punctata (Coleoptera,Coccinellidae)

The isolation of N-quinaldyl-L-arginine·HCl (1) from the CoccinellidaeSubcoccinella-24-punctata is reported. The structure, first established on the basis of the analysis of the spectral properties of1, has been confirmed by synthesis. The alkaloid is of endogenous origin and markedly deterrent to ants.     

Molecular evidence for increased hematopoietic proliferation in the spleen of the b/b laboratory rat

The splenomegaly and the appearance of a significant number of CFU-E (erythroid colony-forming units) and BFU-E¹ (erythroid burst-forming units) in the Belgrade laboratory rat (b/b) spleen prompted us to analyse further the molecular evidence for increased hematopoietic proliferation in the b/b spleen. Messenger RNAs (mRNAs) specific for globins, proteins for iron transport and deposition and the band 3 protein were used in rat erythropoietic tissues as markers for proliferation and erythroid differentiation. In the b/b spleen, all mRNAs analysed display an erythroid-specific pattern of expression. This analysis also revealed an enhanced level of mRNA for ferritin in the +/b spleen, whereas erythrocyte-specific mRNA production was normal.     

Arousal and fright responses and their habituation in the slippery dick,Halichoeres bivittatus

Summary Behavioral arousal and fright responses ofHalichoeres bivittatus occurred in aquaria to a moving shadow and a tap stimulus. Arousal was characterized by changes in the beat of pectoral fins, dorsal fin erection and eye movements, whereas in fright, adduction of pectoral and dorsal fins and rapid forward movement occurred. Serial stimulus presentation caused the fright response to be replaced by arousal which habituated in that the proportion of behavioral components exhibited decreased during the process.P.R. Laming was in receipt of a Royal Society travel grant for assistance in the expenses of this work, for which he is duly grateful. We are grateful to Nick Zinkowski, Culebra for the loan of minnow traps.     

High-affinity binding ofβ-alanine to cerebral synaptosomes might involve glycine-receptors

Summary High-affinity, Na⁺-independent binding of -alanine to a synaptosomal fraction of rat brain was potently inhibited by glycine and by some other -amino acids, but not by taurine or GABA. This binding mechanism, which was also sensitive to both bicuculline and strychnine, might involve synaptic receptors for both -alanine and glycine.This study was supported in part by Centro Ramón y Cajal and Fundacion Juan March.     

Control of obesity inA vy /a mice by 5α-androstan-17-one

Summary Treating VY/WfL-A ^vy /a mice with 5-androstan-17-one, a mammalian glucose-6-phosphate dehydrogenase inhibitor, prevented the mice from becoming obese. The weight difference between treated and controlA ^vy /a mice was mainly due to a decreased accumulation of triacylglycerol. The compound did not suppress appetite, had no detectable toxicity and did not affect the lipogenesis rates in the liver and carcass. The weight-controlling effect of 5-androstan-17-one inA ^vy /a mice was reversible upon withdrawal of treatment.The authors wish to thank Mr W.R. Gibson and Drs C.G. Culbertson and P.N. Harris for performing the pathological examinations.     

Reciprocal changes in serum free thyroxine fraction and thyrotropin level after administration of thiocyanate to rats

Summary The administration of thiocyanate to rats caused a significant increase of serum free thyroxine fraction, which coincided with the significant decrease of TSH level. The other components (AFT₄, T₄, T₃) in serum at this time were decreased or unchanged. The finding suggests the role of free thyroxine fraction in feed-back regulation of TSH secretion.Acknowledgment. We thank Dr A. Parlow and the NIAMDD, Rat Pituitary Hormone Distribution Program, for material for rat TSH immunoassay; Dr J. Nauman (Inst. Postgrad. Med., Warsaw, Poland) for T₃ antibody, and to Ing. J. Sadlo, Mrs M. t'astná and Miss R Fajkoová for technical assistance.     

Age-dependent response of lactate dehydrogenase of pituitary of rat to testosterone

Summary The effects of time and various doses of testosterone on the responsiveness of lactate dehydrogenase of pituitary of 7-, 38- and 78-week-old rats were studied. The activity of the enzyme increases in 78-week-old rats. Castration decreases the enzyme activity at all ages. Maximum increase in the enzyme activity is seen with 50 and 100 g of testosterone 4 h after administration of hormone to castrated rats. No further time and dose-dependent effect is observed. The magnitude of increase for the enzyme is higher at the age of 38 weeks and decreases in 78-week-old rats.To whom all correspondence should be addressed. The authors are grateful to Professor M.S. Kanungo, Biochemistry Laboratory, Department of Zoology, Banaras Hindu University for the suggestions and encouragement. K.V.G. thanks the PL-480 for a research fellowship.