Volume 20, Issue 8

Evidence for the presence of OH-groups in solid alkaline meta-, para-B- and ψ-metatungstates is given by infrared and 1 H-nuclear magnetic resonance spectra. The three tungstates have to be formulated as M I 6 [W 12 O 38 (OH) 2 ] • x H 2 O, M I 10 [ W 12 O 36 (OH) 10 ] • x H 2 O and M I 12 [W 24 O 72 (OH) 12 • x H 2 O respectively. The mole masses of the different polytungstates were calculated from the speed of sedimentation in the ultracentrifuge. In the concentration range covered, 10 -2 > Cwo 4 2 Ⓡ > 10 -4 , the same ions occur as in the solid state. The effect of aging and heating on polytungstate solutions was studied by means of pH-measurements, by pH-titrations, by ultraviolet spectra, and by the T-jump relaxation method. The para· tungstate-A-ion [W 6 20 (OH)] 5 ® formed upon acidification of a H®/WO 4 2 ® = 1,167 ratio solution according to the equation 6 WO 4 2 ® + 7 H® ⇄ [W 6 O 20 (OH)] 5 ® [log K ∼ 57,5] is in equilibrium with the paratungstate-B-ion [W 12 O 36 (OH) 10 ] 10® . In a solution of solid paratungstate-B the same equilibrium is attained. Upon aging and, more rapidly, by heating the para-A-/para-B-solution in equilibrium changes to -ψ-meta and finally to metatungstate. During this process an increase in the pH-value is observed due to the reduced acidity of the para-B-ion and to the enhanced condensation of para-(probably of para-B only) to ψ-meta and further to metatungstate. Upon acidification to the H®/WO 4 2® ratio Ρ=1,50 the ψ-meta-ion is formed quantitatively which changes to the metaion slowly. For P=1,50 characteristic ultraviolet absorption bands indicate the formation of a new polytungstate species [ W 12 O x (OH) y ] 72 — ( 2x+y ), called polytungstate-Y. It changes rapidly and quantitatively to ψ-meta-tungstate. In aged solutions with P ≧ 1,50 only the meta-ion is found. In solutions with Ρ < 1,50 WO 4 2e , polytungstate-X-ions were found besides meta-ions. The relative concentration of these ions as a function of Ρ is given. The so-called X-species is probably the para-B-ion. By means of a scheme, the reactions upon acidification of a monotungstate solution are illustrated.

Two soluble antigens produced in KB-cells after infection with Adenovirus type 2 were identified with constituents of the virion itself. Purification and concentration of the two proteins (named A- and C-Protein according to PEREIRA) is described. The sedimentation rate of the A-Protein is 11.5 S, which gives a molecular weight of 310 000, and the corresponding data for the C-Protein are 5.5 S and 81 000 molecular weight. The A-Proteins of different types, 2, 3 and 5 are physically similar, but serologically composed of parts with similar and parts with type-specific differences.

The influence of versene, Mg 2⨁ , Ca 2⨁ and protamine on the interaction of 32 P labelled RNA with suspended amnion cells was investigated. Versene in concentrations above 5 x 10 -3 M leads to an increase in the amount of cell bound 32 P-RNA. The cell bound RNA is to a large extend resistent to the action of RNase only so long as versene is present. When versene is washed from the cells, RNase acts on 32 P-RNA as it does in the control cell culture. In the absence of cells, versene does not interfere with the action of RNase. Protamine seems to favour the penetration of RNA into cells, whereas Mg 2⨁ and Ca 2⨁ show little influence on the interaction.

The fate of 32 P-RNA was followed after interaction with suspended amnion cells. The adsorbed 32 P-RNA was reisolated together with unlabelled cellular RNA before and after incubation with pancreatic RNase. In both instances part of the RNA can be recovered from the cells with an apparently unchanged molecular weight. The experimental results favour the hypothesis that some 32 P-RNA molecules are selected in the first cycle of interaction with cells so that reisolated high molecular weight 32 P-RNA is more readily adsorbed in a second cycle.

Extremely thin layers of ribonuclease were irradiated with slow protons and the differential inactivation cross section determined for various proton energies in the range from 0.8 to 60 keV. At higher proton energies the inactivation cross section is not strongly dependent on energy but with decreasing proton energy it decreases rapidly, reaches a sharp minimum at 1.2 keV and increases again at still smaller energies. By comparing the experimentally determined inactivation cross sections with the cross sections for energy loss in elastic nuclear collisions and in ionizations, respectively, elastic collisions were demonstrated to destroy, in fact, the enzymatic activity of ribonuclease. The energy required for an inactivation by nuclear collision is only one fourth of the energy necessary for an inactivation by ionization.

The results of biochemical and clinical investigations of a number of azoospermia cases are presented. It was found that serious testicular complaint is usually accompanied by a reduction in the volume and a disturbance in the concentration of the constituents of the accessory gland secretion. Statistical analysis of the fructose concentration indicated that the minimum fructose average was that of the Klinefelter.

Es wird auf die Mannigfaltigkeit der Kontraste hingewiesen, die sich bei mit Aldehyden fixiertem, in Vestopal W oder Durcupan ACM eingebettetem Gewebe durch gesteuerte Elektronenbestrahlung erreichen läßt. Voraussetzung für einen einwandfreien Vergleich von Kontrasten bei z. B. verschieden gefärbten Schnitten ist daher eine Bestrahlung, die zu ausreichend definierten Objektveränderungen führt. Brauchbar in diesem Sinne ist eine Bestrahlung, die zum maximalen „reinen Strahlenverlust“ führt, bei der aber thermische Substanzverluste vermieden werden. Der Negativkontrast von Chromatin und Nucleolen und die offenbar physikalisch bedingte Färbbarkeit der nucleinsäurehaltigen Zellbestandteile mittels der „negative-staining“-Methode werden diskutiert.

The inactivation of homozygous yeast strains of different ploidy by some dyes in the presence and in the absence of visible light was investigated and the results were compared with the reactions of thiopyronine. The influence of some of these dyes on nucleic acids was also examined. Only those dyes which gave precipitates with nucleic acids in aqueous solution activate yeast cells in the absence and — even in smaller concentrations — in the presence of visible light.

Dipterex and its homologues have been prepared by a single vessel reaction in good yields. The stability of O,O-dimethyl-2,2,2-trichloro-1-methoxyethyl phosphonate I b towards temperature and pH variation has been studied using P 32 -labelled compounds. Compared with the parent substance (Dipterex), I b is much more stable. The anticholinesterase activity of Dipterex was found to be over 300 times higher than that of the methyl ether I b ; thus proving that the presence of the free hydroxyl group in Dipterex and its anticholinesterase activity are correlated.

Ultrathin sections of L. corynoides, a recently described heterofermentative species, show very large mesosoms (plasmalemmosoms) which are very often located at the areas at which new crosswalls originate. The interior of the mesosom, which is surrounded by the plasmalemma (cytoplasmic membrane) contains tubulous structures partly distributed irregularly, but partly arranged in parallel to form packets which show regular patterns when cross-sectioned. The tubuli originate by finger-like intrusions of the plasmalemma; they are 150 A thick and contain an inner duct of a diameter of about 30 A. The three layers of the plasmalemma can be recognized on crosssections of the tubuli. The outer, dark layer forms the outer ring of the tubuli, and the somewhat lighter inner layer forms the corresponding inner ring.

The formation and maturation of the egg of the liverwort, Sphaerocarpus donnellii, was investigated by light, phase contrast and particularly by electron microscopy. The division of the central cell into the egg and the ventral canal cell, and the maturation of the egg, is completed within four days. All stages of this formation and maturation were examined under the electron microscope after fixation in KMnO 4 or OsO 4 . — In the maturing egg there always occur the endoplasmic reticulum, well recognisable plastids with a poorly developed lamellar system, numerous mitochondria and dictyosomes, a rising number of lipid droplets, unknown small bodies limited by a unit membrane, and numerous ribosomes. During maturation the nucleus considerably enlarges and forms evaginations into the cytoplasm. Starch is increasingly deposited in the plastids. A degeneration of plastids has not been found.

Thylakoids from chloroplasts of Antirrhinum majus and of the blue-green alga Oscillatoria chalybea form folds during the drying on support films. Under favourable conditions, negative staining with uranylacetate gives electron micrographs of these folds which correspond to crosssections of thylakoids. In these preparations the thylakoid membrane seems to consist of a monolayer of particles. These are insoluble in organic solvents. The center to center distance of the particles approximately agrees with the roentgenographically determined center to center distance of the protein particles in the thylakoid membrane. It was not possible to demonstrate lipids in the thylakoid membrane. Because of the background structure of the support film, electron micrographs gave no unequivocal results concerning the structure of the protein layer in surface view.