Band 20, Heft 12

A survey of the quantum efficiencies of ultraviolet photolysis of a range of substituted pyrimidine nucleosides has been made. The effects of substituents are considered in terms of electronegativity and steric hindrance.

Das EPR-Spektrum des [Cu(NH 3 ) 4 ] 2Θ -Ions im Gitter des Magnus schen Salzes wird angegeben und diskutiert. In Übereinstimmung mit dem beobachteten Elektronenaustausch entlang der Metall-Metall-Kette zeigen solche Einkristalle in Richtung der kristallographischen c-Achse bei zunehmender Temperatur steigende Leitfähigkeit.

Die IR-Spektren von SPF 2 Cl und SPF 2 Br im Bereich 4000 < ν (cm -1 ) < 300 werden mitgeteilt und teilweise nach Gruppenfrequenzen und Symmetrierassen der Punktgruppe C s zugeordnet. Der Frequenzgang der Valenzschwingungen in der Reihe SPF 2 X (X = F, Cl und Br) wird eingehend diskutiert und z. T. mit demjenigen in der entsprechenden Reihe OPF 2 X verglichen. Weiterhin wird eine neue Darstellungsmethode für SPF 2 Cl und SPF 2 Br beschrieben.

In dieser Arbeit hat der Autor bewiesen, daß wäßrige Sublimatlösungen, bei Anwesenheit von Ammoniumoxalat, im Ultraschallfeld Reduktionsprozessen unterliegen. Die ausgeschiedene Kalomelmenge hängt von der Konzentration der HgCl 2 -Lösung und von der Beschallungsdauer ab. Die Kalomelausbeute ist ebenfalls von der Art des sich in der beschallten Lösung befindlichen Gases abhängig. Am günstigsten verläuft der Reduktionsprozeß wenn Argon, am ungünstigsten wenn Wasserstoff beigemischt wird. Eine geringe Zugabe von Aceton zur Ederschen Lösung verursacht gänzliche Reduktionshemmung. Glycerin, eine Flüssigkeit mit nur geringem Dampfdruck, hemmt erst in größeren Mengen den Reduktionsverlauf. Edersche Lösung, mit Salzsäure angesäuert, wird nicht reduziert.

Carbonylhalogenide des Technetiums Tc (CO) 5 X (X = Cl, Br, J) geben wie diejenigen des Mangans und Rheniums mit verschiedenen Liganden L - N-Basen, Organylen des Phosphors und seiner Homologen, Isonitrilen u. a. - unter Verdrängung von CO Disubstitutions-Verbindungen Tc(CO) 3 L 2 X. Mit Merkaptanen, Merkaptiden und Dithiocarbamiden bilden sich unter Verdrängung von CO und Halogen mehrkernige Carbonylverbindungen mit Schwefelbrücken. - Die Carbonylchloride Tc(CO) 5 Cl und Tc(CO) 3 L 2 Cl lassen sich unter CO-Druck in Gegenwart von AlCl3 in kationische Kohlenoxidverbindungen [Tc(CO) 6 ] ⊕ bzw. [Tc(CO) 4 L 2 ] ⊕ überführen. Aus solchen disubstituierten Kohlenoxidkomplexen entstehen mit Alkalialkoholaten Carbalkoxocarbonyle Tc(CO) 3 L 2 CO 2 R. Für die Durchführung der CO-Hochdruckreaktionen wird eine spezielle Glovebox beschrieben, die ein kontaminationssicheres Arbeiten mit Technetiumcarbonylen erlaubt.

Die Darstellung der N-Chlor-arylguanidine gelingt nur in besonderen Fällen, da meist oxydative Ausweichreaktionen eintreten. Diese N-Chlor-Derivate lagern sich in Schwefelsäure unter Kernchlorierung um. Das Isomerenverhältnis - untersucht am Beispiel des N-Chlor-N′-phenyl-N′-methylguanidins - beträgt o: m: p = 21:17: 62. Dasselbe Ergebnis wird bei der Chlorierung des N-Phenyl-N-methyl-guanidins mit N-Chlor-N′-n-butyl-guanidin erhalten. In beiden Fällen verhält sich also die Guanidinium-Gruppe, trotz ihrer positiven Ladung, als Substituent 1. Ordnung.

Basierend auf der Interpretation der Massenspektren von über 150 N-Trifluoracetyl-peptid-methylestern verschiedener Sequenz und Kettenlänge wurde ein allgemeines Verfahren der Sequenzanalyse von Peptiden entwickelt.

Konkurrenzversuche an Daturaarten zeigen, daß neben dem stereospezifisch inkorporierten Ornithin- [2- 14 C] auch dessen Decarboxylierungs-Produkt Putrescin- [1.4- 14 C] als physiologisch möglicher Precursor der Tropanalkaloide angesehen werden kann. Eine Carboxylierung des Putrescins zu Ornithin in Daturapflanzen ist auszuschließen.

The mechanism of aerobic hydroxylation in the presence of peroxidase and dihydroxyfumarate has been studied. Reduction of molecular oxygen proceeds by the dihydroxyfumarate semichinone and leads to the formation of the O 2 H radical which is reduced to an “oxen atom” as hydroxylating particle. In the peroxidase/dihydroxyfumarate/oxygen system OH radicals are also involved. Since they cannot originate from H 2 O 2 a reduction of oxen atoms to OH radicals has to be assumed. Manganese (II) ions react with oxygen radicals and thereby inhibit hydroxylations by oxen atoms and OH radicals. The reactions involved in the peroxidase/dihydroxyfumarate/oxygen system are summarized in a diagrammatic scheme.

The antibiotic, chloramphenicol, inhibits the in vivo uptake and incorporation of 35 S-methionine into bulk proteins in light and in dark. RNA synthesis is not primarily reduced by inhibitor treatment. There is good evidence that the suppression of substance uptake is due to a previous inhibition of protein synthesis. It has been shown that chloramphenicol blocks the synthesis of chloroplast-protein in light far more strongly than the protein synthesis of other subcellular fractions. There is a slight but constant inhibition of the amino acid incorporation into the proteins of isolated chloroplasts or chloroplast-ribosomes. However, some problems concerning the role of light and the antibiotic interference on the poly-U-stimulated phenylalanine incorporation in these systems remain yet unsolved. Chloramphenicol has no effects on the photosynthetic activities in isolated chloroplasts of mature leaves.

The dependence of photosynthetic yields on both sodium adsorption ratio and osmotic pressure of irrigation water is discussed. As a first example, Zea mays seedlings were exposed to C 14 O 2 in closed photosynthetic chambers for 24 hrs. The chromatographic study of aqueous and alcoholic extracts as well as the hydrolyzed tissue are shown in special tables. Other data concerning respiration rate as well as carbohydrates and mineral metabolism are also studied. The respiration of two weeks old seedlings of Zea mays is compared with the photosynthetic process.

The amino acid sequence of TMV strain vulgare (common strain) was partly reinvestigated with recently modified methods. The results show a reversion of the amino acid sequence of position 44 with 45 and position 125 with 126. An additional amide group was found in position 126, but positions 95 and 106 are free dicarboxylic acids.

The amino acid sequence of U 2, a naturally occurring strain of tobacco mosaic virus, has been determined. In this communication the experimental details are given for the elucidation of the amino acid sequence within three tryptic peptides with 85 amino acids.

The protein structure of spontaneous temperature-sensitive mutants of tobacco mosaic virus has been determined. The protein of the mutants was digested with trypsin, the tryptic peptides were isolated and their amino acid composition quantitatively determined. For those tryptic peptides which have amino acid exchanges, the position of the exchange was localized. The experimental results given in the tables are discussed in the following paper.

The protein structure of temperature-sensitive mutants of tobacco mosaic virus isolated after treatment with nitrous acid has been determined. The results obtained for 15 mutants, presented in this and the preceding paper, are discussed with relation to the spatial structure of the virus rod.

Brucella-phages-adsorption test on killed (70°) cells of all types of Brucella in the pure “S” phase has orientating value for determination of the Genus: “Brucella”. Brucella abortus “S” strains are in 100% positive in this test. Brucella melitensis “S” strains are in 83% positive and in 17% weakly positive. Brucella suis “S” strains are in 100% positive. Brucella atypica “S” strains are mostly positive. All types of Brucella in “R” phase are negative in this test. This experiment is important from point of view of general systematics of bacteria and for the explanation of phage-specific receptors in the “S” and “R” phase.

The kinetic course of poliomyelitis virus production in monolayer cultures of monkey kidney cells is studied by assaying the cell-associated and free virus as well as by observing the cytopathic changes (CPE). The virus production in absence of oxygen is decreased to about 1% of that under aerobic conditions. Only a small part of intracellular virus, usually less than 10%, is released from the cells. The typical cytopathic changes do not occur under anaerobic conditions. The latent period of virus development is not altered in anaerobically maintained cultures. If anaerobiosis is interrupted within the first three hours after infection, virus replication and development of CPE occur in the same degree as under uninterrupted aerobic conditions. The reactions sensitive to lack of oxygen take place during the second half of the virus growth cycle (4 th to 6 th hour). The virus release is not influenced by the presence or absence of oxygen, provided the cells were able to synthetize sufficient amounts of virus under aerobic conditions. The reduced virus production under anaerobic conditions is not caused by the diminished efficiency of the glycolytic metabolism. The reactions sensitive to lack of oxygen are so far unknown.

Männchen und unbefruchtete Weibchen verschiedener Perlidenarten verständigen sich durch Trommeln. Die Frequenz der Trommelstöße wird bei Capnia bifrons und Perla marginata bestimmt. Die Übertragung des Trommelstoßes erfolgt nicht durch Schall (auf dem Luftwege), sondern durch die Erschütterung der Unterlage. Nicht nur diese drei Arten, deren Trommeln bei den Männchen schon früher beschrieben wurde, sondern auch Perla marginata und Isoperla grammatica erzeugen in gleicher Weise Geräusche.

Using recording porometer techniques, evidence was produced for the existence of a regulatory system stabilizing the carbon dioxide concentration within the intercellular spaces of leaves. The guard cells function as effectors, and most probably also as sensors. Measurements by the cells of the carbon dioxide concentration and stomatal movement are two separate processes; the second requires auxiliary energy. The system reacts to disturbances after a time lag. This causes overshoot. Additional strong feedback may lead to stomatal oscillations which sometimes persist, or even increase in amplitude indicating insufficient damping.

The spatial arrangement of tubules building up the prolamellar bodies of proplastids in etiolated bean leaves was investigated by electron microscopy. The basic unit of this arrangement is the tetrahedron *, joining to uniplanar five-membered rings with slightly distorted angles and sixmembered strainless rings designated “chair-form” and “boat-form” (following the nomenclature of the two stereoisomeres of cyclohexane in organic chemistry). The center of the concentric prolamellar bodies is held by a pentagonal dodecahedron. This pentagonal dodecahedron and its environment in the direction of the 6 pentagonal axes are built up by five-membered rings combinated with the six-membered boat-form. The chair-form fills up the intermediate spaces and increases in number removing off the center. As the central pentagonal dodecahedron has six fivefold, ten threefold, and fifteen twofold axes, ultrathin sections of the concentric prolamellar bodies show corresponding 532-symmetry provided that the cutting plane meets one of these axes at right angle.

The non-concentric prolamellar bodies of proplastids isolated from etiolated bean leaves were investigated by electron microscopy. The arrangement of tubules in a number of prolamellar bodies or in parts of them follows the crystal lattice of zincblende (or diamond respectively). This is shown by a comparative study of ultrathin sections of the prolamellar bodies and of models of the (111), (110), (112), and (001) plane and of planes of the zincblende lattice slightly inclined to them, standing at right angles to the table (110). Sections at right angles to the (111), (110), (112), and (001) plane will be discussed.

The non-concentric prolamellar bodies of proplastids isolated from etiolated bean leaves were investigated by electron microscopy. The arrangement of tubules in a number of prolamellar bodies or in parts of them follows the crystal lattice of wurtzite. This is shown by a comparative study of ultrathin sections of the prolamellar bodies and models of the (0001), (11̄02̄), (11̄00), and (11̄01) plane and of planes slightly inclined to them of the wurtzite lattice, standing at right angles to the table (112̄0). The combination of wurtzite and zincblende lattice layers is possible and probably realised.

Tissue cultures of Nicotiana tabacum var. “Samsun” contain an array of phenolic compounds. Beside the known glucose and quinyl esters of the hydroxycinnamic acids three hitherto unreported phenolic acid esters were isolated from tobacco tissue cultures. The analytical and spectral data presented in this paper lead to the conclusion that these compounds are glucosamine esters of p-coumaric, caffeic, and ferulic acid.