A carbon-13 NMR study of benzonorbornene isomers

The carbon-13 NMR spectra of a series of exo-and endo-epimers of 2-substituted benzonorbornene (2-substituent = OH, OCHO, Br, NH₂, NHMe or NMe₂) have been examined. The spectra are readily assigned by comparison with the coupled and off-resonance proton decoupled spectra as well as by the use of shift reagents. Interesting and diagnostic features of the spectra allow the distinction between epimers.     

BIOSYNTHETIC PATHWAYS TO 6-AMINOLEVULINIC ACID INDUCED BY BLUE LIGHT IN THE PIGMENT MUTANT C-2A‘ OF SCENEDESMUS OBLIQUUS*

The X-ray induced mutant C-2A of Scenedesmus obliquus grows heterotrophically but forms only traces of chlorophyll in the dark. Upon illumination, baminolevulinic acid (ALA) is synthesized and chlorophyll is formed. These processes are blue light dependent and cease immediately when the cells are transferred back into darkness. Addition of levulinic acid (LA) inhibits the light-dependent formation of chlorophyll and causes accumulation of ALA by competitive inhibition of the ALA dehydratase (EC. 4.2.1.24). By feeding specifically labelled ¹⁴C precursors to the pigment mutant, inhibiting the ALA dehydratase with LA, accumulating, extracting and analyzing the ALA, two pathways leading towards ALA could be established: glycine and succinyl CoA can be condensed to ALA and the 5 carbon skeleton of glutamate can completely be incorporated into ALA via a second pathway. The glycine-succinyl CoA pathway dominates over the glutamate pathway, but both lead to chlorophyll formation.     

The work function of cathodes for electrons and the performance characteristics of Geiger-Müller counting tubes

Acta physica Academiae Scientiarum Hungaricae - The paper deals with investigations concerning the relation between the work function of GM counting tube cathodes and the performance...     

Über einen speziellen Typ alternierender Knoten

Ohne ZusammenfassungDiese Arbeit wurde von der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Halle 1962 in erweiterter Fassung als Dissertationsschrift angenommen.