“增收宝－3”中氨基酸成分

用日立８３５－５０型氨基酸分析仪对“增收宝－３”中游离的氨基酸进行了分析。结果表明其中含有１５种氨基酸,以脯氨酸含量最高。实验结果揭示,氨基酸可能是“增收宝－３”中抗逆增产的有效成分。     

两种吸血水蛭对光闪烁和水扰动刺激的反应

利用自制的控温实验槽在暗室内进行医蛭科两种吸血水蛭对光闪烁和水扰动刺激的模拟个体生态实验,实验结果的统计分析表明,日本医蛭在１６℃时与照度有极好的正相关关系,而在２２℃时成负相关关系,０．２克体重的个体在两种温度对照度的敏感度均大于０．５－０．６克和１．０－１．３克体重的个体,湖北牛蛭在两种温度时与照度均成正相关关系;０．５克体重的个体在１６℃时对照度的敏感度大于１．０－３．３克体重的个体９．５－     

Synthese der lunularsäure

A ten-step synthesis of lunularic acid, starting from phenyl β-chloropropionate is described. Detailed spectroscopic data are given for lunularic     

Enhancement of citrus resistance to the Mediterranean fruit fly

Precolorbreak treatment of Marsh grapefruit and Shamouti and Valencia oranges with 20 or 50 ppm gibberellic acid (GA) reduced fruit susceptibility to laboratory infestation by Ceratitis capitata (Wiedemann). Treatment effects were dose-dependent and the benefits were most pronounced with the orange cultivars. The implications of these findings are discussed in relation to use of GA treatment for improved fruit fly control in citrus.

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Zusammenfassung In den hier beschriebenen Versuchen wurde untersucht, wie weit durch die Anwendung von Gibberilinsäure (GA) im Freiland die Resistenz von Pampelmuse (Marsh), sowie von Shamoutiund Valencia-Orangen gegenüber Befall durch die Mittelmeerfruchtfliege, Ceratitis capitata (Wiedemann) gesteigert werden kann.In den Jahren 1982/83 spritzten wir in Israel Bäume dieser drei Zitrusarten mit GA in den Konzentrationen von 5 ppm und 50 ppm zu zwei verschiedenen Zeitpunkten vor dem Farbumschlag der Früchte (September, Oktober). Die so behandelten Früchte wurden anschliessend während der Reifeperiode in verschiedenen Zeitpunkten adulten Mittelmeerfruchtfliegen für die Eiablage dargeboten. Diese Exposition wurde sowohl im Freiland mit Früchten am Baum sowie im Laboratorium mit gepflückten Früchten durchgeführt. Untersucht wurde einerseits die Anfälligkeit resp. Resistenz der Früchte bezüglich der Eiablage, andererseits die Entwicklung der Larven in den Früchten.Wir stellten fest, dass die Behandlung mit GA bei Pampelmuse in Abhängigkeit vom Zeitpunkt und Konzentration der Behandlung eine gewisse erhöhte Befallsresistenz bewirken konnte. Bezüglich der beiden geprüften Orangensorten konnten wegen ungünstigen Witterungsbedingungen während der Reifezeit keine schlüssigen Befunde erarbeitet werden.Im Winterhalbjahr 1983/84 wurden Bäume aller drei Zitrussorten vor dem Farbwechsel der Früchte mit 20 ppm und 50 ppm GA behandelt. Um den negativen Einfluss der Witterung in den Expositionsversuchen auszuschalten, wurden die Versuchsfrüchte den Fruchtfliegen während der Reifeperiode ausschliesslich im Laboratorium dargeboten. In dieser Versuchsperiode stellten wir auch bei Orangen eine erhöhte Widerstandsfähigkeit gegen Fruchtfliegenbefall fest, und zwar in erhöhtem Ausmass bei Valencia-Orangen. Gleichzeitig beobachteten wir eine stark verzögerte Entwicklung des Farbwechsels von grün auf orange als Folge der hohen GA-Konzentration.

     

Population dynamics in variable environments. IV. Weak ergodicity in the Lotka equation

The Hilbert projective metric is applied to the continuous-time Lotka equation in demography to establish weak ergodicity: populations with the same time-varying fecundity and mortality schedules ultimately have the same age composition. The analysis displays clearly the dynamic content of Lotka's equation and identifies a contraction operator which forces convergence of birth sequences over time. The relationship between primitivity in the discrete (Leslie) and continuous (Lotka) demographic models is made clear.     

Genetics and ontogeny of alcohol dehydrogenase isozymes in the mouse: Evidence for a cis-acting regulator gene (Adt-1) controlling C2 isozyme expression in reproductive tissues and close linkage of Adh-3 and Adt-1 on chromsome 3

An electrophoretic variant previously reported for the stomach isozyme of alcohol dehydrogenase (ADH-C2) in inbred strains of Mus musculus (Holmes, 1977) has been used to localize the gene encoding this enzyme (Adh-3) on chromosome 3 near Va (varitint) (9.6 ± 3.6% recombinants). Genetic variation of ADH-C2 activity in male and female reproductive tissues among inbred strains and Harwell linkage testing stocks was also observed. Reproductive tissue ADH-C2 phenotypes were inherited in a normal Mendelian fashion among F₂ progeny of an F₁ (LII × C57BL/Go) × C57BL/Go backcross as though controlled by a single cis-acting regulator locus (designated Adt-1) with two alleles: Adt-1 ^a (presence of ADH-C2) and Adt-1 ^b (absence or low activity of ADH-C2). No recombinants were observed among 73 progeny or among 13 inbred strains and six Harwell linkage testing stocks of mice, indicating that Adh-3 and Adt-1 are closely linked or identical genes. A single recombinant phenotype was observed in Peru-Coppock mice, suggesting that they are separate genes. Ontogenetic analyses demonstrated that ADH-B₂ is present throughout development from late fetal stages in stomach, liver, and kidney; similar results were found for ADH-C2 in developing kidney and stomach extracts, whereas ADH-A2 exhibited high activity in liver extracts after 3 weeks of age in both sexes and in male kidney extracts after 6 weeks.     

The N protein of bacteriophage lambda, defined by its DNA sequence, is highly basic.

Nucleotide sequence has been determined for the restriction fragments and cloned DNA from the pL-N-tL1 region of bacteriophage lambda. A unique reading frame for the N gene is defined by the absence of natural nonsense codons and by the presence of seven nonsense codons generated by mutations in N. This reading frame is initiated at two alternative ATG codons, the second of which is probably the in vivo translation start. Reading is stopped at a single TAG codon. The protein coded is therefore 133 or, more probably, 107 amino acids long, rich in lysine, arginine and proline.     

Adrenal medullary cyclic nucleotide phosphodiesterase: lack of activation by the calcium-dependent regulator.

Calcium-dependent regulator, a calcium-binding protein isolated from brain and adrenal medulla, has been shown to activate a brain calcium-sensitive cyclic nucleotide phosphodiesterase. To determine if this protein has the same role in the adrenal medulla, the cyclic nucleotide phosphodiesterase of adrenal medulla was characterized. Neither crude nor partially purified adrenal medullary phosphodiesterase was inhibited by EGTA or stimulated by calcium and the calcium-dependent regulator, whereas similar brain preparations displayed sensitivity to these agents. As the calcium-dependent regulator does not appear to stimulate adrenal medullary cyclic nucleotide phosphodiesterase activity, alternate roles of this protein in adrenal medulla are suggested.     

Membrane-integration Characteristics of Two ABC Transporters, CFTR and P-glycoprotein

To what extent do corresponding transmembrane helices in related integral membrane proteins have different membrane-insertion characteristics? Here, we compare, side-by-side, the membrane insertion characteristics of the 12 transmembrane helices in the adenosine triphosphate-binding cassette (ABC) transporters, P-glycoprotein (P-gp) and the cystic fibrosis transmembrane conductance regulator (CFTR). Our results show that 10 of the 12 CFTR transmembrane segments can insert independently into the ER membrane. In contrast, only three of the P-gp transmembrane segments are independently stable in the membrane, while the majority depend on the presence of neighboring loops and/or transmembrane segments for efficient insertion. Membrane-insertion characteristics can thus vary widely between related proteins.