Über das Fehlen einer Beziehung zwischen dem Kaffeegenuß der Eltern und dem Geschlechtsverhältnis unter ihren Kindern

Ohne ZusammenfassungTeile dieser Arbeit wurden von Fräulein M. Kurth im Rahmen ihrer medizinischen Doktordissertation erarbeitet.Die Untersuchungen der Verfasser zum Mutationsproblem werden durch die Deutsche Forschungsgemeinschaft gefördert.     

Tumor necrosis factor signal transduction. Tissue-specific serine phosphorylation of a 26-kDa cytosolic protein

Binding of tumor necrosis factor-alpha (TNF-alpha) to its receptor on U937 cells results in rapid and TNF dose-dependent phosphorylation of a cytosolic protein with an apparent molecular mass of 26,000 kDa (p26) and an isoelectric point of 5.6. Half-maximal phosphorylation of p26 was achieved at concentrations of 1.8 ng/ml and was detectable within 20 s of TNF-alpha treatment. p26 is phosphorylated exclusively at serine residues. p26 phosphorylation occurs at 37 degrees C as well as at 14 degrees C, indicating that internalization of the TNF receptor is not required for serine kinase activation. Dephosphorylation of p26 starts 10 min after TNF-induced phosphorylation, suggesting a possible regulatory function of this cytosolic protein within the post-TNF receptor signaling system. p26 is also phosphorylated upon treatment with lymphotoxin. In contrast, both interferon-gamma and lipopolysaccharide fail to induce p26 phosphorylation. Whereas phosphorylated p26 was detected in the TNF-sensitive breast cancer cell line CRL1500, other TNF-responsive tumor cell lines investigated lacked enhanced phosphorylation of p26 in response to TNF, indicating that the 26-kDa phosphoprotein (pp26) may be a cell type-specific second messenger molecule involved in TNF signal transduction in some, but not all, target cells. p26 is also phosphorylated in a subclone of U937 (U937.C27) that responds to TNF-alpha with differentiation, yet is resistant to TNF-alpha-mediated growth inhibition. In contrast, p26 is not phosphorylated in another U937 derivative (U937.G3) that is resistant to both TNF-alpha-induced growth arrest and differentiation, suggesting that pp26 may play a role in the TNF signaling pathway linked to differentiation processes rather than to growth control.     

Postmortem Degradation Alters Fluorographic Labeling Patterns and Affinities of Benzodiazepine Binding Proteins

To investigate the effect of endogenous proteolysis on the molecular weights of the benzodiazepine binding proteins, brains of trout, chicken, and rat were removed immediately after death and stored at room temperature for various periods of time before they were frozen. Photoaffinity labeling of membranes with [3H]flunitrazepam, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography, revealed proteolytic fragments of 47K in trout, chicken, and rat. The proteolysis set in rapidly after death. Seemingly in parallel with the degradation observed fluorographically, the affinity for [3H]flunitrazepam increased without systematic changes in receptor density. The degradation pattern was not identical to that of the photolabeled trypsinized benzodiazepine binding proteins. The endogenous proteolytic fragments were deglycosylated in two steps. In conclusion, proteolytic effects must be taken into account when interpreting labeling patterns and binding parameters.     

Identification of two general diffusion channels in the outer membrane of pea mitochondria.

Reconstitution experiments were performed on lipid bilayer membranes in the presence of detergent solubilized mitochondrial membranes of pea seedlings (Pisum sativum). The addition of the detergent-solubilized material to the membranes resulted in a strong increase of the membrane conductance. To identify the proteins responsible for membrane activity the detergent extracts were applied to a hydroxyapatite (HTP) column and the fractions were tested for channel formation. The eluate of the column contained a protein which migrated as a single band with an apparent molecular mass of 30 kDa on SDS-PAGE. This channel was identified as the porin of pea mitochondria since it formed voltage-dependent channels with single-channel conductances of 1.5 and 3.7 nS in 1 M KCl and an estimated effective diameter of about 1.7 nm. Further elution of the column with KCl containing solutions yielded fractions which resulted in the formation of transient channels in lipid bilayer membranes. These channels had a single-channel conductance of 2.2 nS in 1 M KCl and had also the characteristics of general diffusion pores with an estimated effective diameter of 1.2 nm. Zero-current membrane potential measurements suggested that pea porin was anion-selective in the open state. The selectivity of the second channel was investigated by the measurement of the reversal potential. It was also slightly anion-selective. Its possible role in the metabolism of mitochondria is discussed.     

The macrofauna and macroflora associated withLaminaria digitata andL. hyperborea at the island of Helgoland (German Bight,North Sea)

This paper describes the macroflora and macrofauna associated with two bull kelp species,Laminaria hyperborea andL. digitata, at the island of Helgoland, North Sea. During a study period of seven months (March–September 1987), 29 macroflora species and 125 macrofauna species were found. The dominant taxonomic groups were Polychaeta (25 species), Bryozoa (17), Amphipoda (14), Hydrozoa (10) and Ascidiae (8). The species maximum was in July. In general,L. hyperborea was preferred as a substrate for settlement toL. digitata. Composition of the communities associated with kelp changed during the season according to exposure to wave action, and according to location on the kelp thallus. The rhizoid community of both kelps bore more species at exposed locations. Wave-exposedL. digitata lacked obvious faunal settlement on both phylloid and cauloid. Phylloid and cauloid ofL. hyperborea were chosen as an attractive substrate at both sheltered and wave-exposed locations, showing an association of encrusting bryozoan and hydrozoan colonies.     

Ordovician (Dobrotivá Formation) ostracodes and trilobites from Ejpovice (Bohemia) and their relations to faunas of northern and western Europe

For the first time a complete ostracode and trilobite fauna is described from the Dobrovitá Formation (Ordovician) of Perunica. In contrast to the trilobite fauna the ostracode fauna evidences close relations to both Armorica and Baltica. The trilobite fauna comprises 11 species out of 11 genera, the ostracode fauna comprises 15 (5 new) species out of 15 (1 new) genera.