Volume 22, Issue 11

Theoretische Untersuchungen von WIDEROE über eine zunehmende biologische Wirkung schneller Elektronen mit ihrer Eindringtiefe und erste experimentelle Bestätigungen regten zu eigenen Untersuchungen am wachsenden Schwanz der Ratte an. Nach Dosen von 1200 rad mit 14 MeV-Elektronen zeigten die Schwänze junger Ratten gegenüber den Kontrollen signifikante Wachstumsreduktionen, die in 40 mm-Plexiglastiefe um den Faktor 1,16 und in 45 mm um den Faktor 1,24 größer waren als in 10 mm Tiefe. Auf Versuche einer quantitativen Erklärung der experimentellen Ergebnisse unter Voraussetzung verschiedener Energieübertragungsmechanismen wird hingewiesen.

Besitzt der Ligand D eines Metallcarbonyl-Derivates YM (CO) x-1 D bzw. M (CO) x-1 D am Donatoratom eine diagnostische Bindung wie z. B. O = S in O=S(CH 3 ) 2 , so kann aus der Lage der Wellenzahl v dieser Bindung auf die π-Donatorstärke am Metall des Metallcarbonyls geschlossen werden. Aus der Änderung dieser Wellenzahl erhält man die relative π-Donatorstärke am Metall der Metallcarbonyle, was ihre Klassifizierung ermöglicht. Mit dieser Klassifizierung kann über ein Stabilitätsdiagramm die Stabilität noch unbekannter Metallcarbonyl-Derivate abgeschätzt werden.

Die chemischen Verschiebungen δp zahlreicher tertiärer Phosphine, Phosphoniumjodide und Diphosphino-Nickel (II) -chloride wurden bestimmt. Für zahlreiche Liganden sind Inkremente und σ p -Konstanten tabelliert, die, in empirischen Gleichungen verwendet, die Berechnung der chemischen Verschiebungen erlauben. Die Gleichung für die Berechnung der chemischen Verschiebungen δp von Phosphoniumsalzen wurde neu formuliert.

Es wurden die dem kristallinen, sauren Zirkonphosphat H 2 [Zr (PO 4 ) 2 ] · H 2 O analogen kristallinen Verbindungen Zirkonarsenat H 2 [Zr (AsO 4 ) 2 ] · H 2 O, Titanphosphat H 2 [Ti (PO 4 ) 2 ] · H 2 O, Titanarsenat H 2 [Ti (AsO 4 ) 2 ] · H 2 O, Zinnphosphat H 2 [Sn (PO 4 ) 2 ] ·H 2 Ο und Zinnarsenat H 2 [Sn (AsO 4 ) 2 ] · H 2 O dargestellt. Alle genannten Verbindungen sind isotyp. Die bisher für das saure Zirkonphosphat angenommene hexagonale Symmetrie ist bei allen genannten Verbindungen nicht streng erfüllt. Das Kristallwasser ist reversibel gebunden. Amine werden als Ammoniumionen in das Kristallinnere aufgenommen. Diese Ammoniumverbindungen besitzen Ionenaustauschereigenschaften und die Fähigkeit zur eindimensionalen, innerkristallinen Quellung. Damit ist der schichtenförmige Gitteraufbau dieser Verbindungen nachgewiesen.

Versuchsreihen isothermen Abbaus zwischen —78 und —33 °C bewiesen die Existenz eines Triammins und eines Monammins des Ammonium-o-brombenzoates sowie von Di- und Monammin des Ammonium-p-brombenzoates. Die Dampfdrucke der Ammine des NH 4 -o-brombenzoates und der gesättigten Lösungen der Ammoniumsalze in Ammoniak wurden in Abhängigkeit von der Temperatur gemessen und durch Berechnung von Dampfdruckgleichungen nach August charakterisiert. Bei der Bestimmung der Löslichkeit der NH 4 -Salze in NH 3 ergab sich, daß NH 4 -o-brombenzoat oberhalb —61 und unter —72 °C besser in NH 3 löslich war als die p-Verbindung. Es wurden die Dichten bestimmt: Ammonium-o-brombenzoat D 20 ° = 1,62, Monammin D -31° = 1,35, Triammin D -34,1 ° = 1,27, gesättigte Lösung D -34,1 ° = 1,07 g/cm 3 ; Ammonium-p-brombenzoat D 20 ° = 1,46, Diammin D -78 ° = 1,35 g/cm 3 .

Pyrrole has been oxidized in an irreversible wave on a rotating Pt-disc electrode in acetonitrile. When oxidation was carried out in the presence of benzaldehyde it was possible to isolate tetraphenylporphine. The porphine synthesis is initiated by protons formed on the oxidation of pyrrole. Addition and condensation of protonated pyrrole molecules with benzaldehyde formed tetraphenyl· porphinogen, which was oxidized to tetraphenylporphine anodically or by redox reaction in solution. This redox reaction with pyrrole forms dihydropyrrole which proceeds finally to chlorins and explain also the current yield greater than a hundred per cent. This synthesis of porphine can be achieved in a few minutes at -70 °C by addition of acid to a solution of pyrrole and benzaldehyde.

Die Hydrolyse von Tributyrin und Triacetin durch Pankreaslipase wurde unter verschiedenen Reaktionsbedingungen untersucht, die p ʜ -Abhängigkeit sowie K m und V max ermittelt. Einflüsse auf das anomale Temperaturverhalten der Reaktionsgeschwindigkeit wurden geprüft und diskutiert. Das Temperaturverhalten kann in allen Fällen als Änderung der Reaktionsverhältnisse gedeutet werden. Im Gegensatz dazu wies die Hydrolyse mit teildenaturiertem Enzym (69% Restaktivität) keine anomale Temperaturabhängigkeit auf.

The appearance of fr-specific RNA components was followed in two strains of E. coli K 12 growing in supplemented minimal medium. Under these conditions the eclipse period was 25 min. and the latent period 50 minutes. Using pulses with 14 C-uracil for 5 min followed by chases for 10 min, labelled RNase-resistant components appeared simultaneously with labelled material corresponding to phage RNA. The peak of the RNase-resistant components was found to sediment initially at 6 s. As replication progressed, it sedimented with increasingly higher values, reaching a maximum of 11.5 s 80 min after infection. Properties of this RNase-resistant fraction resemble those expected of partially double-stranded material as it is assumed to be present in “replicative intermediates I and II”.

The effect of amino acid deprivation on 14 C-uracil incorporation into phage-specific RNA was compared in strains of E. coli with stringent and relaxed control of RNA synthesis. The incorporation of label into phage-specific RNA persisted for long periods of amin acid starvation in RC reI -cells. In contrast, deprivation of a required amino acid caused an immediate reduction of the incorporation of 14 C-uracil label into cellular and phage-specific RNA-components, especially into 26— 27s-Phage-RNA in RC Str -cells. The results suggest a differential amino acid-sensitivity of RI-I and RI-II synthesis as well as a dual effect of the RC locus on the incorporation of extraneous 14 C-uracil into RNA.

The resistance to N-methyl-N'-nitro-N-nitrosoguanidine (NG) of five single-step mutants of a lysogenic group A Streptococcus after several cycles of growth in NG-free media was within the range of 1.5 to 3.7 times that of the parent. After ultraviolet irradiation (UV) these mutants had a higher chance to survive than the wild type, giving dose reduction factors of 1.4 to 2.4. In prophage induction experiments using UV and NG as inducing agents, the dose induction functions of the NG-resistant strains were either shifted toward higher doses or the efficiency of induction was decreased. In the strains examined caffeine and acriflavine (which are already known to block host cell reactivation) greatly enhanced both the killing and the inducing effect of UV, indicating the ability of Streptococcus pyogenes to perform dark repair of UV damaged DNA. The extra resistance to UV conferred on the strains carrying the NG-resistance mutation was not decreased by UV enhancers, moreover, their action on dark reactivation seemed to be less efficient in these strains.

Eine Anzahl von walzen- und sprühgetrockneten Magermilchpulvern verschiedener Provenienz wurde vergleichend auf Lebernekrose auslösende Wirkung im Versuch an der Ratte und auf den Gehalt an Selen mittels der Aktivierungs-Analyse untersucht. Es ergab sich ein eindeutiger Zusammenhang. Selen-Gehalte von 0,2 μg pro g Trockenmasse und mehr verhinderten die Entwicklung der Mangelkrankheit. Mit absinkenden Selen-Gehalten von 0,1 μg pro g Milchpulver oder weniger ging regelmäßig ein hoher Prozentsatz der Versuchstiere an Lebernekrose ein. Starke Unterschiede wurden beobachtet zwischen den Selen-Gehalten und der Lebernekrose auslösenden Wirkung von Magermilchpulvern geographisch verschiedener Herkunft. Diese Unterschiede sind offensichtlich durch die Verschiedenheit der geologischen Formationen bedingt. Technische Varianten bei der Walzentrocknung hatten keinen Einfluß auf die Lebernekrose erzeugende Wirkung und den Selen-Gehalt der Pulver. Ein systematischer Vergleich von Frisch-Magermilch mit dem daraus hergestellten Vorkonzentrat ergab jedoch einen beträchtlichen Verlust an Selen beim Voreindicken. Bei der Herstellung von Sprühpulver im Laboratoriums-Maßstab aus diesem Konzentrat trat kein weiterer Selen-Verlust auf. Mit zugesetztem Natriumselenit zeigte sich ebenfalls keine Verminderung des Selen-Gehaltes.

Die im Vergleich zum Serum von Kontrolltieren depressive Wirkung des Serums teilhepatektomierter Ratten auf den Stoffwechsel (Sauerstoffverbrauch, Milchsäurebildung) der Ascites-Zellen des Walker-Carcinoms konnte statistisch gesichert werden. Diese unterschiedliche Wirkung zwischen den verschiedenartigen Seren verschwindet nach Dialyse fast vollständig.

The formation of antibodies against rat liver ribosomes was induced by intravenous injections of ribosomal preparations into sheep and rabbits. These preparations did not contain any cytoplasmic proteins detectable by immunoelectrophoresis. The existence of specific antibodies was demonstrated by precipitation, haemagglutination and complement fixation. During incubation of ribosomes with antiserum an aggregation of the ribosomes takes place. Obviously, the formation of dimeric aggregates is a direct antigen-antibody-reaction, which, in a secondary process, may be followed by formation af heavier aggregates, containing at least six ribosomes. These complexes are no longer active in synthetizing proteins in vitro. It may be concluded, therefore, that on the surface of the ribosome the site of antibody fixation is located closely to the protein binding site and the transfer-RNA binding site, respectively.

Chlorpromazin ruft eine Erhöhung der freien Aktivität der Lysosomhydrolasen, des Hämoglobinzerlegenden Kathepsins und der sauren Phosphatasen in Homogenaten, hergestellt aus Lebern von Ratten, welchen einmalig subcutan die Dosis 1 mg/100 g Lebendgewicht injektiert worden war, hervor. Bei der Präinkubation der isolierten von den gleichen Homogenaten reich an Lysosomen Mytochondrialen-Fraktionen in isotonischer Lösung (0,25 M Saccharose) bei 37 °C und PH 5, stellte sich eine beschleunigte (im Vergleich zur Kontrolle) Freilegung der an die Lysosome gebundenen sauren Phosphatase fest. Auf Grund der hervorgehobenen Veränderungen kann man annehmen, daß Chlorpromazin die Lysosommembran labilisiert. Riboflavin, gleichzeitig mit Chlorpromazin angewandt, schützt die Lysosome vor der labilisierenden Wirkung des Chlorpromazins.

The changes in the contents of saturated fatty acids during metamorphosis of female ants and worker ants of the species F. polyctena have been studied paper chromatographically. Myristic, palmitic, stearic, and arachic acids are present, palmitic acid being found in the highest concentration. Myristic and arachic acid comprise less than 5% of the saturated fatty aids in almost all metamorphic stages. Behenic acid has been found in females shortly before the hatching of the adult. The contents of all saturated fatty acids decline during metamorphosis until emergence of the adult. Palmitic acid shows the greatest relative decrease, whereas stearic acid shows a relative increase. In the female prepupal stage the content of saturated fatty acids is relatively lower than in the corresponding worker one. Before emergence of the adult the proportions are reverse. During the metamorphosis therefore the workers consume relatively more saturated fatty acids than the females. The proportions of the saturated fatty acids are similar in the prepupae of the females and workers. During the metamorphosis the content of palmitic acid falls down stronger in females than in workers. The highest decrease is combined with a marked fat reduction. The found differences between the two casts are discussed together with earlier results of their different fat metabolism.

Der mindertoxische, 32 P-markierte Dithiophosphorsäureester Dimethoat wurde durch intramuskuläre Injektion und im Pour on- (Aufgieß) -Verfahren an laktierende Rinder appliziert. Die Konzentrationen der extrahierbaren Substanzen und die Gesamtaktivität an 32 P in Blut und Milch wurden bestimmt. Versuche zur Identifizierung der Metaboliten durch Radio-Dünnschichtchromatographie führten teilweise zum Ziel. Nach intramuskulärer Injektion ergeben sich relativ hohe Wirkstoffkonzentrationen im Blut, welche nur langsam abgebaut werden. Nach percutaner Resorption von Dimethoat aus geeigneten Formulierungen werden im Blut Wirkstoffkonzentrationen erreicht, welche eine ausreichende Abtötung von Endoparasiten ermöglichen, wie durch Insektizid-Tests bestätigt werden konnte.

Control by ligth of hypocotyl lengthening in lettuce seedlings (Lactuca sativa L., cv. Grand Rapids, tip burn resistant strain) has been investigated using high quality monochromatic bands of radiation between 320 and 1100 nm wave length. Continuous irradiation was applied between 54 and 72 hours after sowing. The increase of hypocotyl length during this period was measured. — A set of characteristic dose-response-curves is presented. For the calculation of the action spectrum — relative quantum efficiency (N 447 nm /N λ ) as a function of wave length — the branches of the dose-response-curves between 60 and 80% increase were used. The action spectrum shows a symmetric peak around λ = 716 nm with a band width of 30 nm. This fact agrees with the conclusion 1 that the far-red peak of action in the case of long-time irradiation is exclusively due to phytochrome. The photostationary state [P fr ] / [P] for optimum effectiveness with respect to control of hypocotyl lengthening in lettuce is probably around 3%. — The fine structure of the action spectrum in the blue and ultraviolet range (especially the peak around λ= 363 nm) points to a flavoproteid as the photoreceptor. On the other hand it is well known 1 that with long-time irradiation short wavelengths light as well will maintain photostationary states of the phytochrome system. Further experiments are required to solve the problem of how much of the effect of blue and ultra-violet light can be attributed to phytochrome.

1. Uridine taken up during the 16 th -cell stage of the sea urchin egg is stored in acid soluble form. 2. During the interphase of this stage uridine is used for an RNA-synthesis in the micromeres, the smallest blastomeres of the egg, which have a prolonged interphase. There seems to occur no RNA-synthesis in the other blastomeres of this stage or the synthesis in these cells is considerably smaller. The RNA of the micromeres has a high turnover, it is neither tRNA nor rRNA but probably mRNA. 3. 2½ hours after the 16 th -cell stage — this is in the young blastula stage — about 5½ hours after fertilization, at least half of the micromere-RNA is already decomposed, the fission products of which having been used together with the stored uridine to synthesize rRNA and (after methylation of the uridine) DNA.

Es wird die Isolierung und Charakterisierung der Inhaltsstoffe aus fünf chilenischen Pseudocyphellaria-Arten beschrieben. Pseudocyphellaria intricata (DEL.) WAIN. var. thouarsii (DEL.) WAIN. enthält 7ß-Acetoxy-22-hydroxyhopan (I) und 15ɑ-22-Dihydroxyhopan (II), Pseudocyphellaria durvillei (DEL.) WAIN. Pulvinsäurelacton (III), Calycin (IV), die beiden neuen Triterpene Durvillonol und Durvilldiol sowie eine nicht näher definierte Substanz vom Schmp. 98 — 99°, Pseudocyphellaria hirsuta (MONT.) MALME III, IV, Usninsäure, Ergosterin und D-Mannit, Pseudocyphellaria crocata (L.) WAIN. III, IV und ein phenolisches Produkt vom Schmp. 258—260° und Pseudocyphellaria aurata (ACH.) WAIN. III und IV.

Wir berichten über die Isolierung und Charakterisierung der Inhaltsstoffe dreier chilenischer Roccellaceen. Es enthält: Roccellina luteola FOLLM. das neue Dibenzofuran-Derivat Schizopeltsäure (IV oder V), deren Struktur aufgeklärt wird, ein phenolisches Produkt vom Schmp. 178° und einen Neutralstoff vom Schmp. 295°, Roccellina condensata DARB. Roccellsäure, Portentol und Lecanorsäure sowie Pentagenella fragillima DARB. Psoromsäure.

1. The distribution — before, during and after photosynthesis — of different phosphate esters in chloroplasts and cytoplasm of leaf cells of spinach and Elodea has been investigated. In steady state experiments intact leaves were fed, during illumination, with 14 CO 2 . The kinetics of the distribution of labelled phosphate esters between chloroplasts and cytoplasm were determined. In further experiments with intact leaves fluctuations in the pool sizes of phosphate esters in chloroplasts and in the cytoplasm were recorded in the dark/light and the light/dark transient. Independent fluctuations served as an indication that little or no exchange between chloroplasts and cytoplasm takes place. Concomitant fluctuations suggest rapid exchange. 2. Although labelling takes place in the chloroplasts, a number of labelled phosphorylated intermediates appear rapidly in the cytoplasm during steady state photosynthesis of intact leaves in the presence of 14 CO 2 . This is particularly true for phosphoglyceric acid, glucose-6-phosphate, fructose-6-phosphate and fructose-1,6-diphosphate. On the other hand, labelled ribulosediphosphate, sedoheptulosediphosphate and sedoheptulosemonophosphate remain largely in the chloroplasts. This agrees with earlier work on the behaviour of phosphorylated intermediates during the induction period of photosynthesis. 3. In the dark the level of the bulk of the sugar diphosphates is lower in the chloroplasts than in the cytoplasm of intact leaves. On illumination, a large accumulation occurs only in the chloroplasts. This behaviour suggests impermeability of the chloroplast membrane towards at least some of the sugar diphosphates. In contrast, concomitant large fluctuations in the levels of dihydroxyacetonephosphate and fructose-1,6-diphosphate have been observed during the transients from dark to light and vice versa in chloroplasts and cytoplasm alike indicating that at least one of these compounds functions as a transport metabolite. Changes in the concentrations of glucose-6-phosphate and fructose-6-phosphate were much smaller under the influence of light than those of other sugar phosphates. 4. The results demonstrate the role of phosphorylated transport metabolites in carbon metabolism in chloroplasts and cytoplasm. Implications of these findings in relation to photosynthesis, respiration and the regulation of metabolism are discussed.

1. The interrelationship of metabolic activities in chloroplasts and cytoplasm of leaf cells of spinach, sugar beet and Elodea has been investigated. Different methods have been adopted to study the intracellular localization of enzymes and the flow of phosphorylated intermediates across the chloroplast membrane. The flow of substrates was investigated by determining the rates of the conversion of substrates added to aqueously isolated chloroplasts, prior to and after destruction of the outer chloroplast membrane. The observed differences yielded information as to whether a substrate could traverse the chloroplast membrane. Two methods mere used to investigate the localization of enzymes : a) The percentage distribution of photosynthetic and respiratory enzymes in chloroplasts and cytoplasm was calculated from data on enzyme activities in non-aqueous cell fractions. b) Low levels of enzymes in chloroplasts in the presence of high cytoplasmatic levels were detected by assaying enzyme activities in preparations of aqueously isolated chloroplasts prior to and after ultrasonic destruction of the outer chloroplast membrane. 2. If chloroplasts are isolated in aqueous sucrose buffer, their outer membranes act as an efficient barrier against the penetration of NADP, RuDP, GAP and, in some but not all experiments, of FMP and GMP. PGA, DHAP and, probably to a lesser extent, aspartate, ɑ-ketoglutarate, oxaloacetate and FDP can traverse this membrane. Chloroplast membranes are significantly altered when isolated in NaCI-buffer systems and do not correspond to the in vivo situation. 3. The conversion of Ri-5-P to RuDP occurs exclusively or nearly exclusively in the chloroplasts indicating that phosphoribulokinase and/or ribosephosphate isomerase are located only there. 4. The conversion of Ri-5-P to GAP and SuMP, which is catalyzed by the enzymes ribosephosphate isomerase, xylulosephosphate epimerase and transketolase, proceeds likewise only or at least predominantly in the chloroplasts and not, or only to a small extent, in the cytoplasm. 5. The major parts of glucose-6-phosphate dehydrogenase and of 6-phosphogluconate dehydrogenase reside in the cytoplasm. However, a small, but significant, level of these enzymes is to be found also in the chloroplasts. Hexokinase and transaldolase are also present there. Pyruvate kinase and phosphofructokinase appear to be absent from chloroplasts. 6. Since, with the presence of glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, hexokinase, transaldolase and enzymes of the Calvin cycle, the enzymic machinery of the oxidative pentose phosphate pathway is complete in the chloroplasts, the results suggest that chloroplasts are engaged in the oxidative decomposition of carbohydrates. 7. In the dark the oxidative pentose phosphate pathway requires the control of NADPH formation and the transfer of hydrogen across the chloroplast membrane. 8. The available data on the intracellular localization of enzymes and on the kinetics of the distribution of labelled intermediates show that the photosynthetic carbon cycle operates exclusively within the chloroplasts. There is nothing to suggest that enzymes of chloroplasts and cytoplasm cooperate in the cyclic regeneration of the carbon acceptor molecule. However, the existence of phosphorylated transport metabolites suggests that secondary reactions of photosynthesis such as sucrose and amino acid synthesis, which proceed, at least in part, outside the chloroplasts, are directly linked with chloroplastic reactions by activated (phosphorylated) intermediates.