MORPHOLOGY OF ISOLATED RABBIT HEART MUSCLE MITOCHONDRIA AND THE OXIDATION OF EXTRAMITOCHONDRIAL REDUCED DIPHOSPHOPYRIDINE NUCLEOTIDE

The morphology of rabbit heart muscle mitochondria isolated in several media has been compared by electron microscopy. The internal structure of isolated mitochondria differs from that of in situ mitochondria, with the type and degree of alteration depending on the isolation medium. Examination of the isolated mitochondria after incubation revealed that additional morphological changes occurred during incubation, but these changes were less pronounced when the incubation was conducted in a complete medium containing substrate. The isolated mitochondria have been shown to be capable of catalyzing a slow aerobic oxidation of extramitochondrial reduced diphosphopyridine nucleotide. The rate of DPNH oxidation observed is sufficient to account for the ability of the mitochondria to oxidize lactate in the presence of catalytic amounts of DPNH. The suspensions used were essentially free of mitochondrial fragments, which are known to oxidize DPNH. Possible relationships of these findings to metabolism in situ are discussed. The results indicate the desirability of correlating biochemical activities with the morphology of isolated mitochondria.     

Familientradition in der Gesangsentwicklung des Gimpels(Pyrrhula pyrrhula L.)

Zusammenfassung Der heranwachsende Junggimpel empfängt während seiner Nestlingszeit und den sich anschließenden Wochen bis zum Erlangen der Selbständigkeit von den Eltern Eindrücke, die sein späteres Geschlechtsverhalten und seine stimmliche Entwicklung entscheidend beeinflussen. Ein normales Geschlechtsverhalten entwickelt sich nur dann, wenn der Jungvogel von den eigenen Eltern oder Artgenossen aufgezogen wird. Erfolgt die Aufzucht durch andere Lebewesen (Kanarienvogel, Mensch), so tritt eine mehr oder weniger deutliche Prägung der sozialen und sexuellen Reaktion auf diese Arten ein. Mit dieser Prägung geht eine Fixation der Lautäußerungen (Lockruf, Gesang) an die der Eltern — vor allem des Vaters — Hand in Hand. Trägt der Vater normale Lockrufe und den arttypischen Gesang vor, so erfährt auch der Junggimpel eine ormale stimmliche Entwicklung. Sind aber Lockrufe und Gesang in Klangfarbe und Komposition abweichend, so lernt der Jungvogel selektiv alle diese Abweichungen und behält sie zeitlebens bei. Ein Jungmännchen, das von Kanarien aufgezogen wurde, erlernte unter einer Schar anderer Junggimpel den Gesang des einzigen anwesenden Kanarienmännchens und gab ihn an seine Söhne weiter. Vier Jahre später sangen die Urenkel dieses Vogels noch die Kanarienstrophen in unveränderter Form. — Von Menschen aufgezogene Gimpel konzentrieren ihren Lerneifer auf die Lautäußerungen des Pflegers; sie erlernen vorgepfiffene Melodien: bis zu drei kurze Volkslieder. Während die jungen Männchen ausschließlich dem Gesang des Vaters ihre Aufmerksamkeit zuwenden, nehmen die Weibchen nach ihrer Verpaarung neben den vom Vater erlernten Motiven auch solche aus dem Gesang des Gatten auf. Nur der erste Partner hat auf ihre Gesanganusbildung Einfluß.Die sensible Periode der stimmlichen Entwicklung fällt mit der Zeit zusammen, in der frühsexuelle Stimmungen den Junggimpel beherrschen. Sein Lerneifer ist auf dasjenige Lebewesen konzentriert, das ihn aufzog und dem er — aus dem daraus erwachsenen hohen Grade persönlicher Bindung heraus — seine ersten sexuellen Anträge machte.     

Somatische Mutationen an Flügelschuppen der DörrobstmottePlodia interpunctella Hübner nach Röntgenbestrahlung der Raupen

Ohne ZusammenfassungMit Unterstützung durch die Deutsche Forschungsgemeinschaft. Herrn Dr. A.Wehrmaker danke ich für die Einführung in die praktische Arbeit anPlodia und die Überlassung der Zucht. Herrn Dr.von Woellwarth und Herrn Prof.Krause danke ich für die Unterstützung bei der kritischen Durchsicht des Manuskripts.     

Co-purification of 130 kD nitric oxide synthase and a 22 kD link protein from human neutrophils.

The synthesis of nitric oxide (NO) from L-arginine has been demonstrated in several cell types. Both constitutive and inducible forms of NO synthase have been described in different cells. We purified the constitutive form of NO synthase enzyme in human neutrophils using a two-column procedure. Crude 100,000g supernatant of human neutrophils was passed through a 2'-5'-ADP-agarose column followed by a DEAE-Bio-Gel A anion exchange column. NO synthase enzyme migrated as a single band (MW approximately 130,000) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Its activity was dependent upon nicotinamide adenine dinucleotide phosphate (NADPH) and (6R)-tetrahydro-L-biopterin (BH4). In addition, flavin adenine dinucleotide (FAD) was also found to be essential for its maximal activity. A second NADPH, FAD-dependent component (MW approximately 22kD) was also found consistently on the SDS-PAGE gel. These observations suggest co-regulation between NO synthase enzyme and this NADPH, FAD-dependent component, which may be associated with the superoxide radical generating system.     

Roots of Iron-Efficient Maize also Absorb Phytosiderophore-Chelated Zinc

To investigate the recognition of Zn-phytosiderophores by the putative Fe-phytosiderophore transporter in maize (Zea mays L.) roots, short-term uptake of 65Zn-labeled phytosiderophores was compared in the Fe-efficient maize cultivar Alice and the maize mutant ys1 carrying a defect in Fe-phytosiderophore uptake. In ys1, uptake and translocation rates of Zn from Zn-phytosiderophores were one-half of those in Alice, but no genotypical difference was found in Zn uptake and translocation from other Zn-binding forms. In ys1 and in tendency also in Alice, Zn uptake decreased with increasing stability constant of the chelate in the order: ZnSO4 [greater than or equal to] Zn-desferrioxamine > Zn-phytosiderophores > Zn-EDTA. Adding a 500-fold excess of free phytosiderophores over Zn to the uptake solution depressed Zn uptake in ys1 almost completely. In uptake studies with double-labeled 65Zn-14C-phytosiderophores, ys1 absorbed the phytosiderophore at similar rates when supplied as a Zn-chelate or the free ligand. By contrast, in Alice 14C-phytosiderophore uptake from the Zn-chelate was 2.8-fold higher than from the free ligand, suggesting that Alice absorbed the complete Zn-phytosiderophore complex via the putative plasma membrane transporter for Fe-phytosiderophores. We propose two pathways for the uptake of Zn from Zn-phytosiderophores in grasses, one via the transport of the free Zn cation and the other via the uptake of nondissociated Zn-phytosiderophores.     

Antisense RNA Inhibition of RbcS Gene Expression Reduces Rubisco Level and Photosynthesis in the C4 Plant Flaveria bidentis

The C4 dicot Flaveria bidentis was genetically transformed with an antisense RNA construct targeted to the nuclear-encoded gene for the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; RbcS). RbcS mRNA levels in leaves of transformants were reduced by as much as 80% compared to wild-type levels, and extractable enzyme activity was reduced by up to 85%. There was no significant effect of transformation with the gene construct on levels of other photosynthetic enzymes. Antisense transformants with reduced Rubisco activity exhibited a stunted phenotype. Rates of photosynthesis were reduced in air at high light and over a range of CO2 concentrations but were unaffected at low light. From these results we conclude that, as is the case in C3 plants, Rubisco activity is a major determinant of photosynthetic flux in C4 plants under high light intensities and air levels of CO2.     

Factors inhibiting IFN activity

Several factors may inhibit the activity of IFNs. Some of these occur naturally, others are therapy-induced or artificial. Naturally occurring antibodies appear to have a much broader reactivity than therapy-induced antibodies. Naturally induced antibodies are reported in patients suffering from chronic graft-versus-host disease after bone marrow transplantation. Differences in the reported immunogenicity between interferons may not be due to the minor variation in amino acid sequence. The clinical significance of therapy-induced antibodies has been unclear. In patients treated for chronic hepatitis C, antibody formation is closely related to relapse. In animal studies the efficacy of treatments targeting the IFN receptor interaction has been shown. Soluble IFN- receptor inhibits the development of autoimmune diseases in mice. Monoclonal antibodies to the IFN- receptor protects against allograft rejections in monkeys. Two naturally occurring inhibitors of IFN action were reported. The clinical significance and structure of these inhibitors remain elusive.