Die Bedeutung waagerecht liegender Augenteile für die photomenotaktische Orientierung des Rückenschwimmers

Ohne Zusammenfassung     

Entwicklungsformen und Degeneration im Xanthoria-Apothecium

Ohne ZusammenfassungD 88     

Retinomotorik und Adaptationsvorgänge im Auge des Rückenschwimmers (Notonecta glauca L.)

Ohne Zusammenfassung     

Zur Morphologie der Leberzellmembran

Zusammenfassung Die Leberzellmembran und ihre Bildungen wurden im Bereich der Sinusoide, der Gallenkapillarwand und der aneinandergrenzenden Parenchymzellen bei Mäusen, Ratten, Meerschweinchen, Goldhamstern, Kaninchen, Tauben und Gold-fischen vergleichend untersucht. Im Gebiet des Disséschen Raumes sind keine sicheren Unterschiede zu finden. Dagegen liegen im Bereich der Gallenkapillaren und der aneinandergrenzenden Parenchymzellen viele charakteristische Struktur-elemente vor, so daß bei der Untersuchung dieser Membranteile eine Zuordnung der Leber zu einer bestimmten Tierart im allgemeinen möglich ist.     

Purification and properties of dimethylallylpyrophosphate: Tryptophan dimethylallyl transferase,the first enzyme of ergot alkaloid biosynthesis in Claviceps. sp. SD 58

Dimethylallylpyrophosphate:l-tryptophan dimethylallyltransferase (DMAT synthetase), the first pathway-specific enzyme of ergot alkaloid biosynthesis, has been isolated from mycelia of Claviceps sp., strain SD 58, and purified to apparent homogeneity. The enzyme reaction products were identified as l-4-(γ,γ-dimethylallyl)tryptophan and inorganic pyrophosphate. DMAT synthetase is a single subunit protein of molecular weight 70,000–73,000 and has an isoelectric point at pH 5.8. The enzyme is activated by Fe²⁺, Mg²⁺, and particularly Ca²⁺; K_m values for l-tryptophan and dimethylallylpyrophosphate were determined to be 0.067 and 0.2 mm, respectively. Kinetic analysis indicated that the DMAT synthetase reaction proceeds by a sequential rather than a ping-pong mechanism.     

Oligomeric Dop1p is Part of the Endosomal Neo1p‐Ysl2p‐Arl1p Membrane Remodeling Complex

Yeast Dop1p is an essential protein that is highly conserved in evolution and whose function is largely unknown. Here, we provide evidence that Dop1p localizes to endosomes and exists in a complex with two other conserved proteins: Neo1p, a P₄‐ATPase and putative flippase, and the scaffolding protein Ysl2p/Mon2p. The latter operates during membrane budding at the tubular endosomal network/trans‐Golgi network (TEN/TGN) in a process that includes clathrin recruitment via adaptor proteins. Consistent with a role for Dop1p during this process, temperature‐sensitive dop1‐3 cells accumulate multivesicular, elongated tubular and ring‐like structures similar to those displayed by neo1 and ysl2 mutants. In further agreement with the concept of Dop1p‐Neo1p‐Ysl2p complex formation and co‐operation, we show that dop1‐3 cells exhibit reduced levels of Neo1p and Ysl2p at steady state. Conversely, mutations or deletions in NEO1 and YSL2 lead to a decrease in Dop1p levels. In addition to binding to Neo1p and Ysl2p, Dop1p can form dimers or multimers. A critical region for dimerization resides in the C‐terminus with leucine zipper‐like domains. Dop1p's membrane association is largely mediated by its internal region, but Ysl2p might not be crucial for membrane recruitment.