Volume 25, Issue 7

An attempt is made to apply the Green's function procedure to the case of linear XYZ type molecules. The isotopic rules have been formulated. The potential energy constants and mean amplitudes of vibrations of the various molecules of the linear XYZ type have been determined. The force constants of the different groups are discussed in the light of the ionic character or electronegativities taking recourse to the resonance structures wherever possible. The coriolis ζ sum rule for the linear XYZ type molecules have been verified. The rotational distortion constant Dj for the linear XYZ type molecules were determined and the calculated values were compared with the experimental values for the case of HCN, DCN, BrCN, ICN, NNO and OCS molecules.

Zweikernige Nitrosyl-Carbonyl-Komplexe der Struktur (ON) 2 MPR 3 -Mn (CO) 5 und (ON) 2 MPR 3 -Co(CO) 3 PR 3 (M = Co, Fe; R = C 6 H 5 ) entstehen durch Umsetzung der phosphinsubstituierten einkernigen Nitrosyl-Verbindungen von Kobalt und Eisen, M(NO) 2 PR 3 Br, mit Na[Mn(CO) 5 ] und Na[Co(CO) 3 PR 3 ]. Die Reaktion mit Na[Fe(CO) 3 (NO)] verläuft im Gegensatz dazu unter Bildung der einkernigen Verbindungen Co(NO) (CO) 2 PR 3 und Fe(NO) 2 (CO)PR 3 . Anhand von IR-Spektren werden die Struktur- und Bindungsverhältnisse diskutiert.

The activating influence of a nitrophenyl substituent in the intramolecular alkylation of compounds of the type 3 and 5 has been studied. The investigation establishes that the activation afforded by a 4-nitrophenyl substituent is intermediate between that of a carbonyl and ester functions. The role of the N-aryl substituent in the alkylation of N-aryl, N-α haloacetamino esters and ketones has also been studied. A number of hitherto unreported lactams have been synthesized and characterized. Synthesis of the compound 4 c using a weak base is of special interest, since this lactam possesses only a single electronegative substituent at the 4-position.

The new route to the synthesis of 3-oxo-1,4-oxazines 1 has been extended. N-aryl-N-chloroacetyl-m-nitro-phenacyl amines afford either only oxazine, or beta-lactam or both depending on the nature of the N-aryl substituent. A set of rules indicates from which precursors beta-lactam, as against morpholine formation, may be expected.

The unequivocal identification of phenylthiohydantoins of the 20 amino acids usually occurring in proteins is possible by mass spectrometry and by combined gas chromatography-mass spectrometry. The method is sensitive enough to be applied to the identification of phenylthiohydantoins obtained from automated Edman degradations of polypeptides. Mass spectra of 21 amino acid phenylthiohydantoins are presented and interpreted.

The uropygial (preen) gland fat of the partridge (Perdix perdix) is a mixture of diester waxes of which even- and odd-numbered fatty acids with a chain length of C 9 -C 20 are shown to be the acidic component. On the other hand erythro-n-alkanediols (2,3) with a chain length of C 12 - C 23 are the alcoholic components of the waxes. The simultaneously investigated depot fat is a mixture of triglycerides with usual composition. Chemotaxonomically the partridge is a typical member of the 18th order (galliformes) of the natural system.

From the aqueous extract of the heartwood of Gmelina arborea (N.O.: Verbenaceae), a lignan has been isolated and identified as gmelinol on the basis of its chemical and spectral analysis. From the benzene extract of the same heartwood, n-octacosanol has been isolated as one of the constituents.

The influence of some reducing agents and SH-reagents on the quality of the electrophoretic separation of soluble proteins from barley seedlings in acrylamide-gel was investigated. Admixture of 2-mercaptoethanol or 2,3-dimercaptopropanol produces sharp bands but splits disulfide bonds of the proteins. To avoid this, ascorbic acid together with cysteine can be used as antioxidants. Sulphite or pyrosulphite is unsuitable to protect barley seedling proteins against oxidation. Weakly active oxidizing agents for thiols like arsenite hardly influence the quality of protein separation. Stronger agents, however, for instance H 2 O 2 , disturb band formation in the gel columns. Low concentrations of alkylating and mercaptide-forming agents promote the sharpness of the bands. With higher concentrations of SH-reagents derivatives from proteins and arise impede good protein separation in gel columns.

With the aim of studying the biosynthesis of psoralen and bergapten, two furocoumarins present in the leaves of “Ficus carica” (Moraceae), the Authors, continuing preceding researchs on this topic, have fed the leaves with the following labelled precursors: 4′,5′-dihydropsoralen, 4′,5′-dihydrobergapten, 7-hydroxycoumarin, 5,7-dihydroxycoumarin and 5-methoxy-7-hydroxycoumarin. The results obtained indicate that all these substances are certain biogenetic precursors for psoralen and bergapten. On the basis of the results obtained the biosynthetic pathway of furocoumarins seems to involve first of all the formation of a coumarinic derivative 7-hydroxylated, then an isoprenylation reaction which leads to the formation of the hydrogenated furan ring, finally dehydrogenation of the 4′,5′-dihydrofurocoumarins to psoralen and bergapten.

Von den ca. 80 im Bananenaroma von uns gefundenen Estern weisen ca. 40 Methylverzweigungen auf. Diese werden strukturell von Leucin und Valin abgeleitet, was durch Zufuhr von 14 C-mar-kiertem Leucin und Valin bei Bananenscheibchen nachgewiesen werden konnte.

We investigated the behaviour of RNA from the cotyledons of sterile mustard seedlings (Sinapis alba L.) under conditions were Pf r , i. e. the active phytochrome, will rapidly mediate enzyme induction, e. g. phenylalanine ammonia lyase induction. Using double labelling technique of RNA ( 14 C-uridine, 3 H-uridine) and separation of the RNA on MAK 1 -columns we could not find any change of the RNA fractions within 20 min after the onset of light, i. e. within 20 min after the formation of Pf r in the seedling. The results indicate that the MAK-method of RNA separation is not precise enough to reveal small differences at the level of rapidly labelled RNA. Positively, we conclude that Pf r mediates morphogenesis not by dramatic regulatory changes but by induction and repression of a relatively small number of enzymes 2 .

In mixtures of 1 volume of buffer and 2 volumes of 2-chloroethanol, the icosahedral bacteriophage fr is split into RNA and monomeric protein subunits. After removal of the RNA and after replacement of the organic solvent by water, viruslike particles can be obtained by dialysis of the protein against neutral buffers of high ionic strength, whereas multishell particles are formed in buffers of low ionic strength. All results achieved by the use of 2-chloroethanol are very similar to those obtained using acetic acid.

The amino acid sequence of the murein of A. atrocyaneus was determined. The peptide subunits L-Ala-γ-D-Glu-L-Lys-D-Ala are crosslinked by the interpeptide bridge L-Ala-L-Ala-L-Ser. The α-carboxyl group of D-glutamic acid is substituted by glycine amide which was never found in any other murein so far.

1. In intact leaves of Elodea densa illumination resulted in a large increase in the levels of chloroplastic and cytoplasmic ATP and a decrease in chloroplastic and cytoplasmic ADP. Reverse changes were observed on darkening. The kinetics of the fluctuations were similar in chloroplasts and cytoplasm suggesting effective transfer of ATP and ADP between chloroplasts and cytoplasm. Ratios of ATP to ADP were significantly lower in the chloroplasts than in the cytoplasm in the dark and in the light. This may indicate different phosphate potentials in chloroplasts and cytoplasm. Transfer of ATP across the chloroplast envelope as calculated from the light-dependent cytoplasmic ATP increase was 7 to 9 μmoles/mg chlorophyll per hour. Actual transfer rates are probably higher. 2. The determination of the rate of adenylate transfer across the envelope of intact isolated chloroplasts requires information on the composition of chloroplast preparations. Intact chloroplasts were quantitatively separated from envelope-free chloroplasts by density gradient centrifugation on Ludox gradients. The percentage of envelope-free chloroplasts in preparations of intact chloroplasts was also determined from measurements of light-dependent ferricyanide reduction. 3. During isolation in sorbitol buffer ca. 50% of the adenylates were lost from intact chloroplasts which were still capable of high rates of phosphoglycerate reduction and photosynthesis. 4. Adenylate transfer across the envelope of isolated chloroplasts as measured by the light-dependent phosphorylation of added ADP in the absence of cofactors was slow and occured at a rate of 0 to 4 µmoles/mg chloroplyll per hour. In the dark chloroplastic adenylate kinase reacted only very slowly with added AMP and ATP to form ADP. Breakage of the chloroplast envelope stimulated reaction rates. 5. Indirect transfer of ATP and ADP across the chloroplast envelope occurred via a shuttle transfer of phosphoglycerate and dihydroxyacetone phosphate. 3-phosphoglyceraldehyde is not involved as a transport metabolite. Maximum transfer rates of phosphoglycerate and dihydroxyacetone phosphate across the chloroplast envelope were higher than maximum rates of photosynthesis and reached 300 μmoles/mg chlorophyll per hour. Indirect transfer of ATP was somewhat slower than rates of phosphoglycerate reduction by isolated chloroplasts. In vivo transfer of phosphate energy by this transport metabolite system is under control of the redox state of pyridine nucleotides and of the phosphate potential.

The π-electron densities, bond orders, free valences, and reactivity indices according to Fukui's “frontier orbital”-model were calculated for all reactive centers of porphin, chlorin, bacteriochlorin and phlorin by means of Self Consistent Field (SCF) calculations using the approxima tiaons of Pariser, Parr, and Pople. The results were compared with known experimental facts. The relative reactivities of different reactivity centers (e. g. methine-bridges and β-pyrrolic carbon atoms) are well predicted by calculated π-electron densities, whereas the characteristics of similar reactivity centers (e. g. the different methine-bridges in chlorin) are better reflected in the reactivity indices of the “frontier orbital’ model. Reasons for the partial inadequacies of the models used are shortly discussed.

Concentrations of 10 µg/ml rifampicin reduce the growth of Agrobacterium tumefaciens by more than 90%, concentrations of 100 µg/ml prevent tumor formation in Kalanchoë daigremontiana by the same bacteria. A treatment with rifampicin does not irreversibly alter the bacteria; after removal of the drug bacterial propagation and the ability of tumor induction are restored. 0-24 h treatments of the plant wounds with rifampicin prior to infection prevent tumor formation completely. Addition of rifampicin after infection inhibits tumor formation optimally if the drug is added only few hours after inoculation. 30 h after infection the bacteria-host-system is resistant against rifampicin. 100 μg/ml rifampicin do not influence the growth of already induced tumors.

Es wird der Gehalt nativer Schnittpräparate von Leber und Niere gesunder Ratten sowie einer Reihe transplantabler Tiertumoren an proteingebundenen SH-Gruppen (PSH) und nicht-protein-gebundenen SH-Gruppen (NPSH) quantitativ bestimmt, und zwar nach Inkubation in isotoner NaCl- und isotoner 5·10 -3 ᴍ Lösung von 4-Hydroxypentenal (ΗΡΕ). Es ergab sich folgendes: 1. Die Leber weist den höchsten Gehalt an NPSH auf, in den NPSH-Gehalten der übrigen Präparate zeigen sich keine aufschlußreichen Unterschiede. 2. Das gleiche wird für die SH-Gehalte der löslichen Proteine (PSH) gefunden. 3. Nach Einwirkung von ΗΡΕ sinkt der NPSH-Gehalt der Leber auf ca. 19% der Kontrollen, der aller übrigen Präparate auf Null ab. 4. Die durch ΗΡΕ bewirkte Abnahme der PSH-Werte dagegen steht offenbar in einem quantitativen Zusammenhang mit den bei den verschiedenen Präparaten außerdem festgestellten Atmungshemmwerten. Die PSH-Abnahme beträgt bei der Leber nur ca. 1% und die Atmungshemmung ist praktisch Null; es folgen Niere und Yoshida-Sarkom, schließlich zeigen das Ehrlich-Ascites-Carcinom, Stamm Heidelberg und London sowie Sarkom 180 und Lymphosarkom NK/Ly die höchsten PSH-Verluste (40 bis 50%) und praktisch 100-proz. Atmungshemmung. Der Chemismus der Reaktion zwischen ΗΡΕ und SH-Gruppen wird interpretiert und eine mögliche Schutzfunktion der NPSH gegenüber ΗΡΕ erwähnt.

Liver ribosomes from rats pretreated with carcinogenic agents release a ferritin fraction which differs from that of normal ribosomes. This was demonstrated by disc-electrophoresis of the native protein and of the subunits produced by LiCl-urea-treatment. Moreover, the nucleoproteids into which those ribosomes dissociate during incubation with protease-free ribonuclease show a significant alteration in their electrophoretic pattern. - The Michaelis - constant of ribonuclease was found about hundredfold higher, which indicates that the superficial RNA structures are masked by the pathological ferritin to a greater extent than the RNA of normal ribosomes.