Mating patterns of virgin and inseminatedDrosophila melanogaster of different alcohol dehydrogenase (Adh) genotypes

Summary Female choice mating experiments showed virgin femaleD. melanogaster of the 3Adh genotypes chose heterozygous (Adh ^F /Adh ^S ) males most commonly. Inseminated females chose mates randomly, but the likelihood of a female remating was genotypically dependent.Acknowledgment. Financial support was provided by the Australian Research Grants Commitee.     

Genotype-isopropanol interaction in theAdh locus ofDrosophila buzzatii

Summary Drosophila buzzatii, when reared in a medium with isopropanol, shows a significant band interconversion in ADH zymograms and a general lowering of ADH activity. Changes in activity are greater inAdh ^F homozygotes than inAdh ^S homozygotes and generate a significant genotype-isopropanol interaction. These mechanisms are relevant to an explanation of the high naturalAdh polymorphism of this species.This work has been partly supported by a fellowship from the Instituto Nacional para la Asistencia y Promoción del Estudiante (INAPE). We are much indebted to the personnel of the Departamento de Bioquímica, Facultad de Farmacia, Universidad de Santiago de Compostela, for their help in using the facilities at that Department.     

Allozyme polymorphism and linkage disequilibrium ofAdh and α-Gpdh loci in wine cellar and field populations ofDrosophila melanogaster

Summary Over three years, theAdh and -Gpdh loci have been studied in two cellar populations ofDrosophila melanogaster and in two field populations which were each near to one of the cellars. Analyses of gene frequencies indicate that the divergence among subpopulations is greater in theAdh locus than in the -Gpdh locus. Selection for or againstAdh ^S allele acting on theIn(2L)t inversion influences of the -Gpdh alleles. This phenomenon may contribute to explain the maintenance of theAdh and -Gpdh polymorphism and of theIn(2L)t inversion.     

Properties of a calcium-dependent apyrase in the saliva of the blood-feeding bug,Rhodnius prolixus

Summary The saliva of the blood-feeding bugRhodnius prolixus contains at least 11 proteins, and has Ca²⁺-dependent apyrase activity. The activity has a broad pH optimum between pH 7 and 9, and is inhibited by Mg²⁺. Polyacrylamide gel electrophoresis and gel filtration suggest the possibility of at least 2 enzymes responsible for the activity.This work was supported by the National Science and Engineering Research Council of Canada. We are grateful to D. F. Mettrick for use of equipment, and to R. Hewson for invaluable assistance.     

Taxuspine D,a new taxane diterpene fromTaxus cuspidata with potent inhibitory activity against Ca2+-induced depolymerization of microtubules

A new taxane diterpenoid, taxuspine D (1), possessing an enolacetate moiety, has been isolated from stems of the Japanese yewTaxus cuspidata Sieb. et Zucc., and the structure elucidated on the basis of spectroscopic data. Taxuspine D (1) markedly inhibited Ca²⁺-induced depolymerization of microtubules.     

Unstable genetic system inDrosophila melanogaster: I. Instability at theCinnabar locus

Summary A mutant strain containing acinnabar allele (cn ^rbr ,rojo brillante) is reported, that produces wild-type revertants at thecinnabar (cn) locus. Incn ^rbr /cn heterozygotes the rate of mutation is highly increased. The presence of a mutator agent acting premeiotically is indicated.D.L. Lindsley and E.H. Grell, Genetic variations ofDrosophila melanogaster. Carnegie Institution of Washington, Washington, 1968; Publication No. 627.     

Effect of mercuric acetate on mobilization of N and P during germination and seedling growth ofCicer arietinum

Summary Mercuric acetate, at 5.0×10^–5 M, stimulates the mobilization of total nitrogen and phosphate reserves from cotyledons during seedling growth inCicer arietinum cv H208 whereas it suppresses the same process at 2.5×10^–4 M.Thanks are due to Dr D. Banerji for providing facilities and helpful suggestions.     

Abnormal organization of ovarian follicles in the mutantl(1)su(f) mad-ts ofDrosophila melanogaster

Summary The morphology of ovarian follicles in the temperature-sensitive female-sterile mutantl(1)su(f) ^mad-ts has been studied by means of light and electron microscopy. As the follicle cells gradually degenerate at the restrictive temperature (29°C) the follicles become increasingly disorganized with respect to shape and polarity.Acknowledgments. This work was supported by the Deutsche Forschungsgemeinschaft (SFB 46). We wish to thank Mrs R. Koppa for excellent technical assistance and Mrs G. Mahlke for photographic work. We are also indebted to Dr D. Zissler, Dr E. Gateff and Prof. K. Sander for many helpful suggestions.     

Gitterkonstanten und Raumgruppe von Tetrammincuprisulfat

Summary The space-group of Cu(NH₃)₄SO₄·H₂O isD _2h ¹⁶ orD _2h ¹³ (D _2h ⁵ , D _2h ¹ ) with a=7,07, b=12,12, c=10,66 Å ± 1%.     

Association of DNA replication with nuclear membrane in larvae ofChironomus thummi

Summary In the larvae ofChironomus thummi, the newly replicating DNA has been found to be associated with the nuclear membrane, as evidenced by the isolation of DNA nuclear membrane complexes (M-band) of³H-thymidine labelled larvae.Acknowledgment. The authors thank Dr D. S. Pradhan for discussions and encouragement.     

Zur Biosynthese des Plumierids

Summary It has been shown that the leaves ofPl. acutifolia incorporate acetate-1-¹⁴C and mevalonate-2-¹⁴C specifically for the formation of the aglycone moiety of plumieride.

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Wir danken dem Schweizerischen Nationalfonds sehr für die Unterstützung der Arbeit, Herrn Dr.J. Würsch (F. Hoffmann-La Roche & Cie., Basel) für markiertes Mevalonsäure-lakton und Herrn Prof.D. Arigoni (Zürich) für interessante Diskussionen.     

On the synthesis of serine and homoserine samples asymmetrically labelled with tritium and deuterium in the hydroxymethylene group

Summary (1 R) [1-³H,²H₁] 3-Phenylpropanol, the key intermediate in the synthesis of (4 R) [4-³H,²H₁] D, L-homoserine and of the (4 S)-isomer, is obtained from (1 S) [1-²H₁] 3-phenylpropanol and (1 RS) [1-³H] ethanol upon incubation with yeast alcohol dehydrogenase and NAD⁺; under similar conditions 2-phenylethanol undergoes very small exchange with [1-²H₂] ethanol.     

Induction of cell contact sites by Ca2+-EDTA pulses inDictyostelium discoideum

Summary The effect of extracellular Ca²⁺ on the differentiation of the cellular slime moldD. discoideum was examined. In the case of sustained application of calcium, cells required at least 60 min for the presence of calcium to show the induction of EDTA resistant cell contact sites (csA). However, the application of 12 pulses of calcium, followed after 30 sec by EDTA, giving a total time of Ca²⁺-exposure of 6 min, could induce csA on the cell surface.     

High affinity recognition of a <Emphasis Type="Italic">Phytophthora</Emphasis> protein by <Emphasis Type="Italic">Arabidopsis</Emphasis> via an RGD motif

The RGD tripeptide sequence, a cell adhesion motif present in several extracellular matrix proteins of mammalians, is involved in numerous plant processes. In plant-pathogen interactions, the RGD motif is believed to reduce plant defence responses by disrupting adhesions between the cell wall and plasma membrane. Photoaffinity cross-linking of [¹²⁵I]-azido-RGD heptapeptide in the presence of purified plasma membrane vesicles of Arabidopsis thaliana led to label incorporation into a single protein with an apparent molecular mass of 80 kDa. Incorporation could be prevented by excess RGD peptides, but also by the IPI-O protein, an RGD-containing protein secreted by the oomycete plant pathogen Phytophthora infestans. Hydrophobic cluster analysis revealed that the RGD motif of IPI-O (positions 53–56) is readily accessible for interactions. Single amino acid mutations in the RGD motif in IPI-O (of Asp⁵⁶ into Glu or Ala) resulted in the loss of protection of the 80-kDa protein from labelling. Thus, the interaction between the two proteins is mediated through RGD recognition and the 80-kDa RGD-binding protein has the characteristics of a receptor for IPI-O. The IPI-O protein also disrupted cell wall-plasma membrane adhesions in plasmolysed A. thaliana cells, whereas IPI-O proteins mutated in the RGD motif (D56A and D56E) did not.Received 23 October 2003; received after revision 5 December 2003; accepted 12 December 2003     

Drosophila melanogaster does not dealkylate [14C]sitosterol

Summary Drosophila melanogaster was unable to dealkylate and convert [¹⁴C]sitosterol to cholesterol and no evidence was found for conversion of [¹⁴C]desmosterol to cholesterol. Therefore,D. melanogaster is incapable of dealkylating and converting C₂₈ and C₂₉ phytosterols to cholesterol.The authors thank O. J. Duncan III, and H. S. Symonds for technical assistance. Mention of a company name or proprietary product does not imply endorsement by the U.S. Department of Agriculture.     

Inhibition sélective des «vraies» et «pseudo»-cholinestérases du rectus de grenouille

Summary The hydrolysis of acetylcholine chloride (0.01M) by frog's rectus extracts, is inhibited by low concentrations of 3318 CT (CI-50 3.2×10^–7) and high concentrations of D.F.P. (CI-50 1.3×10^–5). Inversely, the hydrolysis of butyrylcholine perchlorate is inhibited by low concentrations of D.F.P. (CI-50 3×10^–9) and high concentrations of 3318 CT (CI-50 3×10^–4). Both are inhibited by similar concentrations of neostigmine (CI-50 1.1×10^–7 and 1.5×10^–7). Frog's rectus thus contains true and pseudo-cholinesterases. The inhibitions produced by D.F.P. added to the muscle itself (and not the extract) correlates well with the potentiation of the corresponding ester. Sensitization to AcCh and to BuCh appears to be specifically related to the inhibition of Ac ChE for the former ester, of XChE for the second one.     

Unit dimensions and space group of Tl2Cl3

Zusammenfassung Die Struktur von Tl₂Cl₃ gehört wahrscheinlich der Raumgruppe D _3d ² an. Die hexagonale Zelle hat die Dimensionena=14·3 k X,c=25·1 k X und enthält 32 Einheiten Tl₂Cl₃.     

The properties of an arginine auxotroph ofSalmonella typhimurium

Résumé L'auteur décrit un mutant auxotrophe pour l'arginine chezSalmonella typhimurium. Les prototrophes arg⁺ sont induits par les rayons UV, MnCl₂ et méthane sulfonate d'éthyle. Le-propiolactone est moins efficace pour l'induction des arg⁺. La transduction avec le bactériophage PLT-22 cultivé sur une souche prototrophe donne arg⁺ à une fréquence de 1/10⁷ bactériophages. Le mutant arg^– est fécond ni avec les souches d'Escherichia coli K-12 HfrC et HfrH ni avec trois souches deKlebsiella pneumoniae.

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I am very grateful to Professor D. G.Catcheside, F.R.S., for his invaluable encouragement and advice, and to the Agricultural Research Council for the award of a Research Studentship.     

Polarographic determination of the reaction rate of the second step in an SN1 displacement

Zusammenfassung Die Zeitabhängigkeit des polarographischen Stromes, welche man bei der gemäss SN1 verlaufenden Hydrolyse vonp-Methoxy-2-phenylpropylchlorid beobachtet, ermöglicht die Bestimmung der Geschwindigkeitskonstantenk ₁ der Gesamtreaktion sowie auch der Geschwindigkeitskonstantenk ₂ des zweiten raschen Schrittes, welcher nach pseudo-erster Ordnung verläuft. Fürk ₂ ergibt sich in Aceton, das 5% Wasser enthält, bei 25°Ck ₂=2,0×10³ sec^–1.

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We would like to thank the N.R.C. for provision of a grant to purchase the Electrochemical System and the University of New Brunswick for a Fellowship for one of us (D.B.).     

The endocannabinoid system in rat gliosomes and its role in the modulation of glutamate release

The endocannabinoid system and endocannabinoid receptor-driven modulation of glutamate release were studied in rat brain cortex astroglial gliosomes. These preparations contained the endocannabinoids N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol, as well their major biosynthetic (N-acyl-phosphatidylethanolamines-hydrolyzing-phospholipase D and diacylglycerol-lipase) and catabolic (fatty acid amide-hydrolase and monoacylglycerol-lipase) enzymes. Gliosomes expressed type-1 (CB1R), type-2 (CB2R) cannabinoid, and type-1 vanilloid (TRPV1) receptors, as ascertained by Western blotting and confocal microscopy. Methanandamide, a stable analogue of anandamide acting as CB1R, CB2R, and TRPV1 agonist, stimulated or inhibited the depolarization-evoked gliosomal [³H]d-aspartate release, at lower and higher concentrations, respectively. Experiments with ACEA (arachidonyl-2′-chloroethylamide), JWH133 ((6aR,10aR)-3-(1,1-dimethylbutyl)-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]-pyran) and capsaicin, selective agonists at CB1R, CB2R and TRPV1, respectively, demonstrated that potentiation of [³H]d-aspartate release was due to CB1R while inhibition to CB2R and TRPV1 engagement. These findings were confirmed by using selective receptor antagonists. Furthermore, CB1R activation caused increase of intracellular IP3 and Ca²⁺ concentration, suggesting an involvement of phospholipase C.