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.     

Effects of 60 Hz electric and magnetic fields on maturation of the rat neopallium

This study was undertaken to determine the effects of extremely low frequency (ELF; 60 Hz) electromagnetic (EM) fields on somatic growth and cortical development, as well as biochemical and morphological maturation, of the rat neopallium. On the fifth day of pregnancy, female rats were put in pairs into plastic cages that were housed in a specially constructed apparatus for irradiation under three separate sets of combination and intensity: 1) 1 kV/m and 10 gauss; 2) 100 kV/m and 1 gauss; and 3) 100 kV/m and 10 gauss. The dams were exposed for 23 h daily, from days 5 through 19 postconception after which they were returned to cages outside the exposure apparatus until they littered. The neonates were culled to eight pups per litter. At 0 (birth), 5, 12, and 19 days postnatally, they were killed for biochemical and morphological studies. Another group of pregnant rats was sham-exposed in an identical apparatus, which was not energized, and the pups were used as controls. The irradiated rats exhibited no physical abnormalities, nor did they show brain deformities such as swelling or herniation following exposure to ELF-EM fields. There was no difference in somatic growth between control and exposed rats, but a small reduction in cortical weight was observed in rats exposed at 1 kV/m and 10 gauss, and 100 kV/m and 1 gauss, respectively. Biochemical measurements of DNA. RNA, protein, and cerebroside concentrations indicated that among the three separate exposures, only the neopallium of rats exposed at 1 kV/m and 10 gauss showed a small reduction in DNA level, as well as small reductions in RNA and protein levels. No changes were noticed in cerebroside levels in any exposed animals, and there were no differences in protein/DNA and cerebroside/DNA ratios between control and exposed rats. Morphological observations did not reveal any detectable alterations in the irradiated rats. These results indicate that exposure to ELF-EM fields caused minimal or no changes in somatic growth and cerebral development of the rat. © 1993 Wiley-Liss, Inc.