Why isPyrrhocoris apterus insensitive to precocene II?

Summary Precocene II (P II) was applied to the adult females of 2 Pyrrhocorid bugs —Pyrrhocoris apterus (insensitive to P II) andDysdercus cingulatus (sensitive to P II)-subjected to allatectomy and intraspecific or interspecific reimplantations of corpus allatum (CA). The failure of P II to inhibit ovarian development inP. apterus appears to be caused by both a low sensitivity to P II of the CA itself and unknown anti-precocene mechanisms outside the CA.Precocene II was kindly supplied by Zoecon.     

Inhibitory tripeptide,Lys-Phe-Tyr,as a fragment of physalaemin

Summary Several peptides were separated from-chymotrypsin-treated physalaemin by high voltage paper electrophoresis, and inhibition of the excitability of a molluscan giant neurone (tonically autoactive neurone) by the tripeptide, Lys-Phe-Tyr, was demonstrated.We thank Dr Sadaaki Iwanaga of Osaka University and Dr Atsuo Inoue of Daiichi Pharmaceutical CO for their helpful advice and the donation of the tripeptide (Lys-Phe-Tyr).     

Mikrobiologischer Nachweis von Antibiotika auf Dünnschichtchromatogrammen

Summary Numerous tetracyclines, penicillins and rifomycins on thin layer chromatograms may be detected by microbiological development withSarcina lutea andBacillus subtilis in the presence of triphenyltetrazolium salts. This technique is exceptionally sensitive (0.01–0.1), the inhibition zones being much sharper than on paper chromatograms.     

Slow current changes underlying square shaped potential waves in warmedAplysia neurones

Summary On warming, the regularly firing L₁₁ neurone ofAplysia turns into a bursting-type neurone. The bursts of spikes are produced by slow square waves which can also be obtained at room temperature by adding TTX or Co⁺⁺. Experiments with slow ramp voltage clamp show that warming induces a negative slope (or negative resistance) on the current-voltage characteristic and very slow current variations (=10 to 50 sec) in response to potential changes. The square waves are explained by these two phenomena.     

Effects of the virulence plasmid ColV,I-K94 on the sensitivity ofEscherichia coli to putative environmental inhibitory agents

Summary Derivatives ofEscherichia coli carrying the virulence plasmid, ColV, I-K94 were more resistant than the ColV^– parents to phage Mel but were more sensitive to the hydrophobic inhibitors deoxycholate, erythromycin and lysozyme. The basis for these changes in sensitivity has been examined in ColV⁺ mutants with altered colicin or VmpA protein levels and in ColV⁺ strains with repressed transfer properties.The authors wish to thank the Fondacion Gran Marischal de Ayacucho and the Central Research Fund of the University of London for financial support.     

Effects of water acidification on the distribution pattern and the reproductive success of amphibians

Summary Nine amphibian species were encountered in poorly buffered waters of The Netherlands (alkalinity 1 meq·l^–1). These soft water systems are highly sensitive to acidifying precipitation. The number of species as well as the percentage of waters which harbour amphibian populations are strongly reduced in the extremely acid pH-class . The reproductive success of amphibians is negatively affected by low pH. The eggs become heavily infested with fungi (Saprolegniaceae). In acidifying systems many physico-chemical parameters are significantly correlated with the pH of the water. Strongly acidified waters are characterized by low alkalinity, conductivity and ionic content but high acidity and high concentrations of (heavy) metals and ammonium and a high relative sulphate concentration. Culture experiments with eggs and larvae ofRana arvalis. Rana esculenta, Rana temporaria andBufo bufo show that apart from the pH, elevated aluminium, cadmium and ammonium contents may also affect the reproductive success of amphibians.     

Enzyme immunoassay for arginine vasopressin

Summary A highly sensitive enzyme immunoassay for arginine vasopressin (AVP) was described. The enzyme used was -D-galactosidase fromEscherichia coli, and it was coupled to AVP by using the N-hydroxysuccinimide ester of N-(4-carboxycyclohexylmethyl)-maleimide. The complex was then utilized for the enzyme immunoassay, which could detect 0.5 fmoles (or 0.5 pg) of AVP in the assay tube.     

The sensitive period for yellow phenocopy induction inDrosophila melanogaster

Summary Yellow phenocopies ofDrosophila melanogaster were produced by raising larvae on -DMT contaminated media. Using a survivorship test, the sensitive period for phenocopy induction was found to occur during the third larval instar of development, with increased survivorship at 1% -DMT compared with lower concentrations. It was also found that treatment with -DMT significantly slowed development. These findings are related to the relevant morphological and behavioral developmental pathways and to phenocopy induction.Publication No. 35 from the Evolutionary Genetics Laboratory, University of Auckland.Acknowledgments. We thank the New Zealand Entomology Society for a grant from their Anniversary Fund to R. D. Newcomb and the University Grants Committee, Research Grant No. 394.597 to D.M. Lambert.     

Cytogénétique desLeggada: (1) La formule chromosomique deMus (Leggada)bufo Th., (2) Nouvelles données sur la délétion portant sur le bras court d'unX chezMus (Leggada)triton Th

Summary The author treats 2 topics connected with his studies on the cytogenetics of the African pigmy-mice. (1)Mus (Leggada) bufo Th. shows the primitive complement already detected in other species or subspecies (minutoides ssp ₁,indutus, tenellus, setulosus): 2N=36,N.F.=36, sex chromosomesPR. (2) The deletion of the short arm of oneX-chromosome (X _dc ) was previously observed as heterozygous mutation by 4 in a sample of 7 and 5 . A more important sample (18 , 21 ) gives the following results: 11 X-X, 10 X-X _dc , 18 X-Y. The occurrence of X _dc -X _dc and of X _dc -Y is also very improbable. It is not easy to understand how the chromosomeX _dc may persist in the population if the complementsX _dc -X _dc andX _dc -Y are lethal, which seems to result from these observations.     

Synthese von 22,26-Imino-cholestan-Derivaten

Summary 3, 16-diacetoxy-5-pregnane-20-one and the analogue pregn-5-ene derivative have been converted into (22R, 25R)-22, 26-imino-5-cholestane-3, 16-diol. The configuration at C-22 and C-25 was determined by transformation into the known (22R, 25R)-5-solanidane-3-one. Application of the Ruschig method led to (25R)-22,26-imino-5-cholest-22(N)-ene-3, 16-diol.

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Solanum-Alkaloide. XVI. Mitteilung. — XV. Mitteilung:K. Schreiber undH. Ripperger, Tetrahedron Letters Nr.27, 9 (1960).     

Effects of photoperiod and temperature on reproductive diapause inDrosophila testacea

Summary In photoperiodic adult diapause ofDrosophila testacea, the critical daylength fell between 14 and 16 h at 15°C, but between 13 and 14 h at 18°C. None entered diapause at LD 1014 and LL at 23°C. This species quantitatively responded to daylengths around the critical daylength in the process of diapause induction. The length of the sensitive period seems to change with temperature.     

17β-Hydroxymethyl-Steroide: Darstellung von Derivaten des 17α-Hydroxy-17β-hydroxymethyl-4-androsten-3-ons

Summary Starting from 17-hydroxy-17-hydroxymethyl-4-androsten-3-one, we synthesized 4-chloro-17-hydroxy-17-hydroxymethyl-4-androsten-3-one-17, 20-acetonide and 17-hydroxy-17-hydroxymethyl-1, 4-androstadien-3-one. 11, 17-dihydroxy-17-hydroxymethyl-4-androsten-3-one was obtained from cortisone via methyl-17-hydroxy-3, 11-dioxo-4-etienate.     

Octopamine,dopamine and noradrenaline content of the brain of the locust,Schistocerca gregaria

Summary The octopamine, dopamine and noradrenaline content of the brain of the locust,Schistocerca gregaria has been determined using sensitive radiochemical-enzymatic assays. Octopamine and dopamine are present in high concentration but the noradrenaline content is only 1/25 that of octopamine. Both reserpine and fusaric acid (a dopamine--hydroxylase inhibitor) produce a significant depletion of the octopamine stores.The author is a M.R.C. of Canada Fellow. Thanks are due to Drs.A. A. Boulton, A. V. Juorio, andP. H. Wu for helpful discussion.     

The distribution of some enzymes involved in the steroidogenesis of hen's ovary

Riassunto È stata studiata con metodi istochimici la distribuzione della ⁵-3-idrossisteroide deidrogenasi ( ⁵-3-HSDH) e delle 17-idrossisteroide deidrogenasi (17-HSDH), DPN- e TPN-dipendenti, nell'ovario di gallina ovulante. Mentre la ⁵-3-HSDH è presente in tutti i tessuti a secrezione steroide dell'ovario, la 17-HSDH è localizzata solo nelle cellule della granulosa.     

17β-Hydroxymethyl-steroide: Darstellung von 17α-Hydroxy-17β-hydroxymethyl-4-androsten-3-on aus Reichsteins Substanz S

Summary The synthesis of 17-hydroxy-17-hydroxymethyl-4-androsten-3-one fromReichsteins compound S is described. Transformation of 3,3-ethylenedioxy-17-hydroxy-17-hydroxymethyl-5-androsten into 17-methyl-isotestosterone demonstrates the configuration of the substituents at C-17.     

Triterpenoid XIII. The constitution of barring-togenol D

Zusammenfassung Die Struktur des aus der Frucht vonBarringtonia acutangula Gaertn. isolierten neuen Triterpenoiden, Barringtogenol D, ist als 3:22oxy-16:22-Oxido-olean-12-en ermittelt worden.     

Hydrolysis of amino acid β-naphthylamides by aminopeptidases in the parotid gland

Zusammenfassung Die Aktivität der Aminopeptidasen in Ohrspeicheldrüsen wurde gemessen. Glycyl-Prolin-naphthylamid, Alanin-naphthylamid, Leucin-naphthylamid, Methionin-naphthylamid, und Arginin-naphthylamid wurden von der Mikrosomenfraktion und der löslichen Fraktion schnell gespalten. Das Glycyl-Prolin-naphthylamid spaltende Enzym war in Ohrspeicheldrüsen in relativ grösserer Menge vorhanden. Die Aufspaltung von Glycyl-Prolin-naphthylamid in Glycyl-Prolin und-Naphthylamin wurde papierchromatographisch nachgewiesen.     

16-β-methylprednisone from hecogenin

Zusammenfassung Es wird über die Herstellung des 16-Methylprednisons berichtet, welche vom Hecogenin ausgehend über ca. 15 Stufen durchgeführt wird. Als wichtige Zwischenstufe treten 5-Pregn-16-en-3-ol-11, 20-dion-Acetat und 16-Methylen-5-pregnan-3, 17-diol-11, 20-dion auf: letzteres wird durch eine stereospezifische katalytische Reduktion in das entsprechende 16-Methyl-derivat umgewandelt.     

Further morphological and biochemical studies on normal and hybrid embryos of sea urchins

Zusammenfassung (1) Es wurde bei den SeeigelartenParacentrotus ,Arbacia undSphaerechinus sowie den drei BastardenPar ×Arb ,Arb ×Par undPar ×Sphaer für eine Reihe von Entwicklungsstadien die Anzahl der Kerne pro Keim bestimmt (Tabelle). Der morphogenetischen Hemmung der Bastarde entsprechen herabgesetzte Kernzahlen und parallel eine Herabsetzung der DNS-Synthese. (2) Es wurde bei den genannten reinen Arten und den Bastarden derUmsatz der RNS bestimmt. Er geht in allen Fällen, bei den reinen Arten wie bei den Bastarden, der DNS- Synthese parallel.

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Our work was supported by a grant from the Schweizerischer Nationalfonds zur Förderung der wissenschaftlichen Forschung. We express our sincere thanks to the Nationalfonds and also to the authorities at the Zoological Station at Naples for generous help and supply of materials and facilities. — This paper is thankfully dedicated byF. Baltzer toF. E. Lehmann for his kind hospitality in the Bernese Institute.     

Zur Konstitution des Resibufogenins und Artebufogenins

Summary The structure of Resibufogenin is unambiguously shown to be 3-hydroxy-14, 15-oxido-bufadien-(20, 22)-olide on the basis of new degradation work. Artebufogenin A and Artebufogenin B are 3-hydroxy-14-15-keto-bufadien-(20, 22)-olide and 3-Hydroxy-14-14-keto-bufadien-(20, 22)-olide, respectively.