Die Zucht vonLytta vesicatoria im Laboratorium und Nachweis der Cantharidinsynthese in Larven

Summary Adult males ofLytta vesicatoria (Coleopt., Meloidae) synthesize cantharidin, but females do not, although the substance is present in the females too. We developed a method for rearing larvae of this parasitic beetle in the laboratory. It is shown that there exist 7 larval stages and 4 hypermetamorphic forms (triungulinus, second larva,pseudochrysalis and fourth larva). Larvae from the second to the fifth stage (second larva) synthesize cantharidin. Therefore, we conclude that the substance present in the adult female is at least in part synthesized in the larval period. Nothing is known about the biological significance of this biochemical sexual dimorphism.

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Coleoptera, Meloidae.     

基于C164微控制器的电动自行车变频控制研究

介绍了基于西门子C164微控制器的电动自行车变频控制研究，主要从变频原理、微机控制、系统整体三方面给出了详细的说明，系统设计简单，控制效率高，有很好的发展前途。     

Gene structure and extracellular secretion of Neisseria gonorrhoeae IgA protease

Several human bacterial pathogens, including the Gram-negative diplococcus Neisseria gonorrhoeae, produce extracellular proteases that are specific for human immunoglobulin IgA1. Immunoglobulin A (IgA) proteases have been studied extensively and the genes of some species cloned in Escherichia coli, but their role in pathogenesis remains unclear. Recently we derived a DNA fragment of 5 kilobases (kb) from N. gonorrhoeae MS11 directing extracellular active enzyme in E. coli. Although the mature enzyme of strain MS11 was shown to have a relative molecular mass of 106,000 (Mr 106K) in gels, the DNA sequence of this cloned fragment reveals a single gene coding for a 169K precursor of IgA protease. The precursor contains three functional domains, the amino-terminal leader which is assumed to initiate the inner membrane transport of the precursor, the protease, and a carboxyl-terminal 'helper' domain apparently required for extracellular secretion (excretion). Based on the structural features of the precursor, we propose a model in which the helper serves as a pore for excretion of the protease domain through the outer membrane. IgA protease acquires an active conformation as its extracellular transport proceeds and is released as a proform from the membrane-bound helper by autoproteolysis. The soluble proform further matures into the 106 K IgA protease and a small stable alpha-protein.     

The preparation and antibacterial activity of 3,3′-bis(trifluoromethyl) tetranitrodiphenylamine

Zusammenfassung Eine neue organische Substanz, 3, 3-bis (trifluoromethyl)tetranitrodiphenylamine ist synthetisch hergestellt worden. Die antibakteriellen Eigenschaften gegen Gram-positive Bakterien und gegen Sulfadiazin resistente und empfindliche Arten vonNeisseria meningitidis werden beschrieben.     

Simplifications to substrate preparation for the cultivation of dissociated nerve cells

Résumé Nous avons simplifié la méthode de préparation du substrat «collagène» pour la culture de cellules nerveuses dissociées. On obtient une fixation et une différenciation rapide des cellules sur ce substrat. Les cultures conviennent pour des études morphologiques, biochimiques et électrophysiologiques.

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Chargée de Recherche au CNRS.

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Acknowledgments. The technical assistance of Mrs.Dorea van Weele andMrs. Marie-France Knoetgen is gratefully acknowledged.     

Correlation between agglutinability of concanavalin A and nucleic acid synthesis induced by polyoma virus]

We have previously shown the induction of agglutinability by concanavalin A by abortice infection of BHK 21 cells with polyoma virus. In this system, the maximal agglutination occurred simultaneously with the first mitosis. Using inhibitors of macromolecule synthesis in an amitotic system, we showed that this agglutinability was correlated with cell DNA synthesis.     

Distribution of the a blood-group activity in porcine serum

Summary The A blood-group activity of pig serum is bound to a lipid, in some cases also to a nonlipid fraction. The major lipidic A activity (roughly 50%) is carried with the HDL class, while the VLDL and LDL classes contain roughly 25% each.This work was supported by Forschungsmittel des Landes Niedersachsen.