Volume 22, Issue 10

Die 31 P- und 1 H-Kernresonanzspektren der Verbindungen (C 6 H 5 ) 2 PH, (C 6 H 5 ) 2 PD, (C 6 H 5 ) PH 2 , (C 6 H 5 ) PH (D) und (C e H 5 ) PD 2 sind graphisch und tabellarisch wiedergegeben und interpretiert. Bei der Substitution von Wasserstoff durch Deuterium werden Isotopeneffekte beobachtet. Die Bildung des primären und sekundären Phenylphosphins durch Reduktion der entsprechenden Chloride mit LiAlH 4 verläuft über Komplexe.

Bei der Reduktion von Propentdyopent zu Pentdyopent wird eine Radikalstufe durchlaufen. Propentdyopente der allgemeinen Struktur I 2 verhalten sich zu den Pentdyopenten der allgemeinen Struktur II 3 wie Chinon zu Hydrochinon. Die SR ist, wie in einer späteren Mitteilung ausführlich dargestellt werden soll, der mehrere Stufen durchlaufende Übergang von Propentdyopent zu Pentdyopent. Eine dieser Stufen ist ein Radikal über das im folgenden berichtet wird.

The position (p) of precipitin bands in OUCHTERLONY’S test with tobacco mosaic virus and carnation latent virus depends upon the concentration of agar and electrolyte. This dependence results from the greater diffusional restriction of antigen in comparison to that of antibody. It is suggested that the effect of electrolyte concentration on the antigen in gel is mechanistically the same as the interaction between virus and agar in the sol state. Antisera against seven distantly related viruses of the potato virus S group reacted with carnation latent, potato M, and red clover vein mosaic viruses. This further demonstrates a serological relationship between viruses of the same shape but different normal length.

Experiments are described, showing that DNA solutions with lithium chloride present a hypochromicity, which increases with the molarity of the salt. Different absorbancy versus temperature curves are obtained for different solutions, and it is found that the melting point (Tm) increases with the lithium chloride concentration. When cooling the samples, the absorbancy decreases in a symmetric way. In accordance with this model, a theory of DNA unwinding is proposed, assuming that before the unwinding, it is necessary a stretching of the molecule which eases this process. An extension of these ideas are applied, to the transcription DNA-RNA operation.

Correlation of lactate-concentration and H ⊕ -concentration in tissue of rat DS-carcinosarcoma was tested with an improved method by intravital pH-measuring. After i. v. dosages of glucose the testing was effected by measurement of 24 points equally distributed within the pH-range of about 6.1 — 7.1. Therefrom we compute the acidification factor In the tested pH-range the factor is practically constant.

1. Es gibt verschiedene Meinungen über die Entstehung des Nukleolus. Eine davon geht dahin, daß der Nukleolus von zwei bestimmten Chromosomen (Satelliten-Chromosomen) stammt. Die zweite Meinung geht dahin, daß kein Zusammenhang zwischen den Satelliten-Trabanten-Chromosomen und dem Nukleolus besteht. 2. In der vorliegenden Arbeit wurde das Merokinese-Phänomen verwendet, um die Frage zu klären. Man läßt einen sicheren merokinetischen Stoff auf die Teilungsphasen einwirken. Als Endprodukt der Teilungsphasen entstehen mehrkernige Zellen. Das Problem wurde mit dieser Methode gelöst, ob jeder Kern einen Nukleolus enthält oder ob es nur 1 — 2 Nukleolen in der mehrkernigen Zelle gibt. 3. Eine modifizierte Methode für Färbung der Nukleolen wurde in der Arbeit durchgeführt. 0,15-proz. lodin und 1,0-proz. Fuchsinsäure (12 Stdn.), dann in 0,5-proz. Lichtgrün 30 Sek. gebracht. 4. Es wurde festgestellt, daß jeder Kern in den mehrkernigen Zellen 1—2 Nukleolen enthält. Bis 7 Nukleolen wurden in einer Zelle, die nur 2 Sat-Chromosomen in ihrem Chromosomensatz beinhalten, gefunden. Das bietet einen klaren Beweis dafür, daß kein Zusammenhang zwischen dem Nukleolenaufbau und den Trabanten-Satelliten-Chromosomen besteht.

Studies on heterokaryons forced between sorbose-resistant (transport-defective) mutans of Neurospora crassa and a sorbose-sensitive (transport-intact) wildtype strain show that mutants sor r A-1 and sor r B-57, mapping in separate linkage groups, are recessive to wildtype; a third mutant, not linked to the others, shows intermediate expression of the resistance character for one of two criteria considered. The functional relations between sor r -loci A and B and the amount of resistance caused by defects in both of them have been investigated in forced heterokaryons of the type A - B + A - B, AB - +AB - and A - B + AB - . Pairwise combination of A - with B - resulted in complementation to the sorbose-sensitive wild-phenotype (“no-growth” complementation). The occurrence of no-growth complementation in the double heterozygote supports the conclusion derived earlier that both gene loci A and B are coding for permeases responsible for the uptake of sorbose.

During the different periods of development the mutant rosy of Drosophila melanogaster has been shown to contain yellowish globules in the Malpighian tubes in different number and position (figs. 1, 2). These globules are excreted by the hind-gut. The Chromatographic analysis indicates that the globules of the larvae and the pupae consist of two compounds : 2-amino-4-hydroxypteridine and xanthine. A third compound, the hypoxanthine, is added to the excretory granules in the lumen of the Malpighian tubes of the adults. The larvae of the wild type accumulate all the purines in the fat-body. Besides the accumulation in the fat-body the mutant in contrary excretes xanthine into the Malpighian tubes already during the larval stage. The occurrence of the three substances: 2-amino-4-hydroxypteridine, xanthine and hypoxanthine, which generally are not found in the Malpighian tubes of wild type, and the concentration of the urine by reabsorption of water in the proximal parts of the tubes seem to cause the formation of the solid conglomerates. The formation of uric acid in Drosophila is discussed.

The enzymes O-seryl-N-acetylgalactosaminide glycosidase and N-acetyl-β-D-hexosaminidase were found in the following invertebrates and vertebrates: Adamsia palliata, Mesostoma ehrenbergi, Bugula avicularia, Lumbricus terrestris, Pagurus prideauxi, Helix pomatia, Ciona intestinalis, Brachidanio albolineatus, Rana esculenta, chicken and ox. They were assayed by their action on neuraminic acid-free ovine submaxillary glycoprotein, which contains an O-seryl-N-acetylgalactosaminide linkage, and on phenyl N-acetyl-B-D-glucosaminide respectively. As previously shown for ox spleeen and Helix pomatia, also the two enzyme proteins present in the homogenates of chick embryo and Lumbricus terrestris eluted from Sephadex columns in two separate peaks.

By double diffusion in agar the antigenic composition of four sea urchin species was examined. At least one common antigenic determinant was found in both gametes of all the four species investigated. Furthermore, in all eggs one and in all sperm another common “sex specific” antigenic determinant was established. In spite of the great number of antigenic determinants in each gamete extract, the existence of “species specific” determinants, common to sperm and eggs of one species, could not be determined with certainty.

The dissociation properties of ribosomal RNA from liver and hepatoma were found to be dependent upon the temperature, ionic strength and cationic valency of the solvent. On increasing the temperature the pK values of the Ν 1 H— C 6 =O and N 1 = C 6 — NH 2 groups of nucleobases were displaced towards neutrality due to the thermal cleavage of Η-bridge linkages. Consequently, as the temperature is increased the nucleic acids bind increasingly more equivalents of acid or alkali. On forward- and back-titration hysteresis is observed in the acid pH range and the degree of hysteresis is found to decrease as the temperature is increased. Increasing the ionic strength of monovalent cations from μ=0.005 to 0.05 Na® leads to a reduced binding of equivalents of acid and alkali brought about by the displacement of pK values towards more extreme pH-values and to an increase in the stability of secondary structure. Bivalent cations exert a stronger stabilizing effect on the molecular conformation of nucleic acids than monovalent cations of equal ionic strength. The more pronounced displacement of the PK values of ionizable groups on titration from pH 7 to pH 3 may be attributed to the additional action of bivalent cations as chelate formers. Significant differences in the acid-base properties of ribosomal RNA from liver and hepatoma were observed especially at low temperatures and high ionic strength. At 5 °C and μ=0.1 NaCl less equivalents of acid and alkali are bound by hepatoma RNA than by liver RNA due to a lower degree of dissociation particularly of the N 1 =C 6 —NH 2 , and Ν 1 H — C 6 =0 groups.

1. Bei Untersuchungen des endogenen Stoffwechsels von Mykobakterien wird mit Hilfe eines kombinierten Ogur-Rosen-Schneider - Trennungsganges die säurelösliche Fraktion von Myc. smegmatis isoliert und zur lonenaustausch-Chromatographie vorbereitet. 2. Als Anionenaustauscher wird Wofatit SBW verwendet und die Trennung mittels Gradienten-Elution bei geschlossener Mischkammer durchgeführt. Gute Trennungen werden bei Einsatz eines zu Beginn mit sehr flachem Säure- und Neutralsalzgradienten arbeitenden Elutionssystems erreicht. 3. Durch automatische Messung der 32 P-Aktivität und durch eine spektrophotometrische Messung der erhaltenen Fraktionen wird die Auftrennung kontrolliert. 4. Die erhaltenen Banden werden mit Hilfe der Papierchromatographie weiter aufgetrennt und auf die Anwesenheit von Monosacchariden und Aminosäuren geprüft. 5. Folgende Daten dienen zur Identifizierung der aufgetrennten Metabolite: Elutionsfolge, Rf-Werte, 32 P-Aktivität, spektrophotometrische Auswertung bei saurer und alkalischer Reaktion vor und nach Hydrolyse. In besonderen Fällen werden spezielle Methoden, z. B. Cyanid-Komplex bei NAD bzw. NADP, zur Erhärtung der Aussage herangezogen. 6. Neben den energiereichen Phosphaten und den Phosphorsäureestern der Embden-Meyerhof - Kette werden in den Zellen von Myc. smegmatis alle niedermolekularen Vertreter des Nucleinsäurepools nachgewiesen. 7. Die 32 P-Verteilung kann sowohl aus der bei der lonenaustausch-Chromatographie erhaltenen Kurve abgelesen, als auch durch quantitative Bestimmung des 32 P in den einzelnen Peaks ermittelt werden.

Chloroplasts possess an ATP-P a -exchange activity, which is induced by a transition from acid to base. The reaction is dependant on the presence of Mg 2⨁ and a reducing agent, DTT. The exchange reaction induced by acid-base transition has properties similar to the light-triggered ATP–P a -exchange and the ATP-synthesis induced by acid-base transition.

Copper chelates of chlorophylls “a” and “b” and an oxidized form of bacteriochlorophyll “a” were prepared and separated by an improved method of column and thin-layer chromatography, and their physical properties and thermodynamics involved in the primary metal replacement reaction were studied. In glacial acetic acid the Mg (II) ions of the photosynthetic pigments were replaced rapidly by Cu (II) ions at 40 — 100° and profound physical changes were noted in the chelation products. Copper chelates were not fluorescent while their parent pigments and pheophytins were. A general lowering of absorbance and a blue shift of absorption maxima were observed with the copper complexes. The molar absorptivity values of copper chelates were determined by the metallic microtitration method and the direct analysis of chelated copper by the oxalyldihydrazide (ODH) of copper method. In the present assay, the primary reaction of copper replacement of Mg (II) in the 3 photosynthetic pigments was the bimolecular SE 2 type. The primary reaction lasted only a short time (1 — 5 min) at temperatures of 40 — 90°, and the higher the temperature, the larger the constants of the bimolecular reaction became. On longer treatment, the metal replacement reaction was complicated by the increasing content of pheophytin. The reaction rate constants became progressively smaller in the order of chlorophyll “a” — “b”-bacteriochlorophyll “a”. At 70° the half lives of 20 μΜ chlorophylls “a” and “b” and bacteriochlorophyll “a” for the copper replacement were 1.2, 15.2, and 117.4 minutes, respectively. Based on transition state theory, some thermodynamic constants relevant to this primary metal substitution reaction at various temperatures were calculated, and the possible mechanism involved were discussed.

The amino acid sequence of the peptide moiety of the mureins of Lactobacillus coryniformis and Lactobacillus cellobiosus cell walls was determined. This was accomplished by the identification of peptides obtained after partial hydrolysis of purified cell walls and by the identification of UDP-activated murein precursors accumulated by ᴅ-cycloserine inhibition. The amino acid sequence proved to be : ʟ-ala-ᴅ-glu-ʟ-lys-ᴅ-ala for L. coryniformis and L-ala-D-glu-L-orn-D-ala for L. cellobio-. D-asp D-asp sus. Aspartic acid is involved in the cross-linking of the mureins by forming a peptide bond with the C-terminal D-alanine of an adjacent muropeptide. Glutamic acid as well as aspartic acid are present as amides.

The occurrence of nucleic acids in chloroplast preparations and leaves of Antirrhinum majus has been investigated. Chloroplast preparations isolated from freeze-dried leaves in a non-aqueous medium were found to contain DNA. Characterization of the DNA was based on chemical analyses and density gradient centrifugation. The chloroplast DNA has a density of 1.698 g/cm 3 corresponding to a guaninecytosine content of 37 — 38%. The hyperchromic effect of the DNA has shown its double-stranded structure. Leaf DNA has also been characterized by density gradient centrifugation and shown to contain as major component the nuclear DNA with a density of 1.689 g/cm 3 which corresponds to a guanine-cytosine content of about 31% and a minor component identified as chloroplast DNA. Extraction of the total nucleic acids of chloroplast preparations and their chromatographic separation on methylated serum albumin column yielded 5 fractions as follows: Soluble RNA (fraction I) with s=3.8—4.0, DNA (fraction II) containing small but detectable amounts of an unknown RNA component, two RNA fractions presumable of ribosomal origin with s = 17 (fraction III) and s = 26 (fraction IV), and a RNA fraction heterogeneous in molecular size (fraction V) with s=23 — 50. The soluble RNA has a high GC-content whereas fraction V shows a relative high adenine content. Compared with the nucleic acids from leaves the chloroplast preparations contain the same fractions, differing only in the higher content of fraction III related to the amount of fraction IV. Beside the DNA fraction of leaf extract with the sedimentation coefficient of s = 12 — 13 a further UV-absorbing component with s=5.0—5.5 has been found. Its character is unknown.