Volume 27, Issue 8

Infrared spectra of Diazocyclopentadiene-h 4 and -d 4 in the liquid and vapour phases were studied and almost all fundamental vibrations of the light molecule were assigned on the basis of vapour phase band profile and H/D isotopic shift ratio.

The preparation of a series of methyl-substituted piperidyl-fluorophosphoranes is described, of general formula RR′NPF 4-n Ph n (where RR′N = 2-Me-piperidyl-, 3-Me-piperidyl-, or 4-Me-piperi-dyl; n = 0, 1, or 2), from the cleavage of silicon-nitrogen bonds in methyl-substituted piperidyl silanes by fluorophosphoranes. The structures of the new compounds are deduced from 19 F and 31 P n.m.r. data.

X-ray photoelectron spectra, pseudohalide complexes of gold (III), linkage isomerism Core binding energies of metals in the isomeric (Ph 3 As) 2 Pd (NCS) 2 and (Ph 3 As) 2 Pd (SCN) 2 , and in [AsPh 4 ] [AuX 4 ] (X = CN - , tetrazolate, Cl - , N 3 - ) are reported. S- and N-Bonding mode can be distinguished in accord with semiemperical MO-calculations. XPS-results are correlated with Mößbauer spectra and the metal-cyanide and metal-tetrazolate bonds are discussed.

X-ray diffraction datas Single crystals of SrCeAlO 4 and SrNdAlO 4 were examined by X-ray diffraction. A comparison of the distances of the statistically occupied metal positions of the K 2 NiF 4 -type with Sr 2 CuO 3 stresses the structure relation between the K 2 NiF 4 -type and Sr 2 CuO 3 .

The reaction of C 3 F 7 Fe(CO) 3 [P(C 6 H 5 ) 3 ] I with liquid ammonia yields, dependend on the reaction-time C 3 F 7 Fe(CO) 2 (NH 3 ) 2 I and [C 3 F 7 Fe(CO) 2 (NH 3 ) 3 ] I. In the contrary, C 3 F 7 Fe(CO) 4 I undergoes ammonolysis forming NH 4 F, NH 4 I, NH 4 NCO and CO (NH 2 ) 2 . No stable iron-complex could be obtained.

By cryoscopic titrations and a mathematical analysis of the titrations results the chemism of formation of the heteropolyanion [JMo 6 O 24 ] 5- was investigated.

The change of the volume associated with the acidification of sodium-molybdate-solutions was continuously controlled by dilatometric titrations. Various isopolymolybdates have been identified.

By using the Periodic Bond Chain Vector method a newly prepared combination of forms of highly stoichiometric WO 3 is discussed. Through the consideration of the features of the structure it can be explained, why the observed faces are built. From characteristics of the structure an improved understanding of the origin of so called shear structures of the ReO 3 type family could be derived.

The kinetics of the reaction between alkaline ferricyanide and mandelic acid catalysed by [Os (VIII) ] has beeen studied. The rate of ferricyanide disappearance was found to be proportional to the concentration of mandelate ion and Os (VIII), but independent of the concentration of ferricyanide. Within a limited concentration range of hydroxyl ion [ [OH -1 ] < 0.25 M] the rate varies directly as the [OH⁻]. Effects of SO 4 -2 , ΝO 3 -1 NO 3 -1 and temperature on the rate were studied. ΔΕ, PZ, AS* etc. were evaluated. Mechanism of oxidation of mandelic acid based on the formation of Os (VIII) acid anion complex is suggested.

Attempts to synthesize trichloro-substituted buta-1,3-diene-irontricarbonyl complexes are reported. While from trans-1,2-dichloro-3-chloro-buta-1,3-diene and trans-1,2-trans-4-trichloro-buta-1,3 -diene and triirondodekacarbonyl the correspondingly substituted tricarbonyl (buta-1,3-diene) iron complexes are obtained, 1,1-trans-4-trichloro-buta-1,3-diene under similar conditions does not form an irontricarbonyl complex.

The compound obtained by the reaction of 3-methyl-3-chloro-4-methylene-cyclobut-1-ene is identified as the irontricarbonyl-π-complex of the 2,3-dimethylferrol system.

For the corannulenes 1 to 7 the mean susceptibilities χm, exaltations A and benzene increments Δ̅ are calculated. For all the corannulenes 1 to 7 the exaltation A is > 12 [10 -6 cm 3 Mol -1 ] and consequently these hydrocarbons fulfil the criterium of aromaticity of DAUBEN, WIL-SON and LAITY 2 .

The probabilities of the isomerisation of uroporphyrinogens in hot acid through rotation of one or more pyrrole rings are calculated on the assumption that only one ring at a time can rotate. The calculated results are in agreement with earlier experimental findings.

Activity and activation of ribulose 5-phosphate kinase, ribulose diphosphate carboxylase, phosphoglycerate kinase, and the NADP- and NAD-dependent glyceraldehyde phosphate dehydrogenases from isolated diloroplasts were traced in the course of differential ultracentrifugation. Activation of some of these enzymes was carried out by incubation with NADPH 2 or ATP. Activity of ribulose diphosphate carboxylase could be increased 2,4-fold by incubation with NADPH 2 while phosphoglycerate kinase could not be activated. The degree of activation of the NADP-specific glyceraldehyde phosphate dehydrogenase and ribulose phosphate kinase was correlated with the velocity of sedimentation. Enzymes, which could be activated manifold, sedimented more quickly. Two fractions could be obtained after ultracentri fugation: the sedimented fraction could be highly activated while the fraction in the supernatant could not. It was shown by gel chromatography with Sephadex for the NADP-specific glyceraldehyde phosphate dehydrogenase and ribulose phosphate kinase that the enzyme fractions which could be greatly activated had molecular weights of at least 400 000. In contrast, the enzyme fraction which could not be activated had a molecular weight of 50 000 for the ribulose phosphate kinase and of 240 000 for the glyceraldehyde phosphate dehydrogenases. Results are discussed in the way that a reversible dissociation of a labile enzyme complex takes place between ribulose phosphate kinase, glyceraldehyde phosphate dehydrogenases, and ribulose diphosphate carboxylase. Enzyme activity changes with the state of aggregation. The dissociated enzymes have higher activity than the complexed ones. Dissociation can be performed by ATP and NADPH 2 , which are assumed to be the physiological regulators, and by unphysiological means as dilution and high salt concentrations.

Plastocyanin is released from chloroplasts by sonication, by passing through the French-press, by extraction with detergents, by treatment with organic solvents and by freezing and thawing. No plastocyanin is liberated during osmotic shock of either class I or class II chloroplasts, or by extraction of class II chloroplasts with dilute solutions of EDTA. Under special conditions it is possible to separate grana and stroma lamellae, which retain plastocyanin. The distribution of plastocyanin between these membrane fractions parallels the distribution of photosystem I. The different reactivity of plastocyanin with various chloroplast membrane preparations is not always correlated to plastocyanin content. Other parameters, like pH, seem to influence the interaction of plastocyanin with the surface of the chloroplast membrane.

Chloroplast fragmentation, ATPase, Proton pump, Cyclic Phosphorylation, NH 4 Cl-uncoupling Cyclic phosphorylation and latent ATPase follow the distribution of photosystem I in the chloroplast membrane. Both activities are found higher in stroma lamellae than in grana. The extent of proton uptake is found to be higher in the grana. Since this uptake depends on internal volume and buffer capacity besides proton pump activity, the distribution of the proton pump proper remains to be elucidated. Any fragmentation of the large inner compartment of the chlorolast lamellar system into smaller vesicles results in decreased sensitivity of cyclic phosphorylation to uncoupling by ammonium chloride. Consequently both, isolated grana and stroma lamellae, show decreased uncoupling by ammonium chloride. The effect can be explained by the action of a membrane potential in photophosphorylation which builds up during illumination and might be more stable in a system with the larger number of individual compartments just for statistical reasons. No assumption on changes in specific ion permeabilities during fragmentation of chloroplasts are needed.

When fed to higher plants, hydroxybenzoic acids form O-glucosides unless they contain an ortho-hydroxyl group when glucose esters are formed. The properties and methods of identification of several of these derivatives are outlined.

The flavonols kaempferol, quercetin and isorhamnetin were labelled with 14 C by keeping seven day old Cicer arietinum L. plants in an atmosphere of 14 CO 2 for five days. The purified (U- 14 C) flavonols were applied to cell suspension cultures of Cicer arietinum L., Phaseolus aureus Roxb., Glycine max and Petroselinum hortense. Based on the rates of 14 CO 2 formation and distribution of radioactivity after fractionation of the cells, the flavonols were shown to be catabolized to a very high extent. All four cell suspension cultures possess the enzymatic activity transforming flavonols to the recently discovered 2,3-dihydroxyflavanones. Upon incubation of the flavonols datiscetin and kaempferol with enzyme preparations from Cicer arietinum L. cell suspension cultures, it was demonstrated that the enzymatically formed 2,3-dihydroxyflavanones are further transformed in an enzyme catalyzed reaction. Salicylic acid was found as a degradation fragment of ring B of the 2,3,5,7,2′-pentahydroxyflavanone derived from datiscetin. Neither phloroglucinol nor phloroglucinol carboxylic acid were observed as metabolites of ring A. These in vitro findings were further substantiated by in vivo data because the flavonols kaempferol, quercetin and datiscetin when applied to cell suspension cultures of Cicer arietinum L. and Glycine max gave rise to para-hydroxybenzoic acid, protocatechuic acid and salicylic acid, respectively. It was thus concluded that flavonols are catabolized via 2,3-dihydroxyflavanones with the B-ring liberated as the respective benzoic acid. The data are discussed in connection with earlier findings on the catabolism of chalcones, cinnamic and benzoic acids.

For a flavone-di-glycoside from a garden variety of Viola tricolor L. the structure 5,7,4′-Trihydroxyflavone-6-C-β-ᴅ-glucopyranosyl-8-C-α-ʟ-rhamnopyranoside was elucidated using mainly perjodate oxidation, NMR- and mass-spectroscopy. From the same plant besides the mono-C-glucosides Vitexin, Saponaretin, Orientin and Isoorientin four Apigenin-di-C-glycosides were isolated, one of them proved to be identical with Vicenine-2.

By coupling emodine with α-acetobromo-L-rhamnose according to Koenigs-Knorr frangulin A was synthesized and thereby its final structure proved as 1,6,8-trihydroxy-3-methyl-anthra-chinone-6-O-α-ʟ-rhamnopyranoside.

Rhodopseudomonas gelatinosa grows on citrate anaerobically in the light. Under aerobic conditions citrate cannot be utilized. Citrate is rapidly fermented by Rps. gelatinosa in the dark, and this fermentation is associated with limited growth (one generation). Anaerobically in the light citrate is decomposed much faster than its catabolic products can be used for the synthesis of cellular material. Therefore, acetate and malate are accumulated in the medium. The acetate concentration in the medium after complete consumption of citrate is higher than the original citrate concentration. Acetate is formed by the citrate lyase reaction and by partial degradation of oxaloacetate. After exhaustion of citrate, growth of Rps. gelatinosa continues at the expence of acetate.

Extracts of Chlorobium thiosulfatophilum and of Rhodospirillum rubrum have been tested for the presence of citrate lyase under various conditions. This enzyme could not be detected. It is, therefore, concluded that a complete reductive carboxylic acid cycle does not occur in these microorganisms. The enzymes required for a-ketoglutarate synthesis from oxaloaetate and acetyl-coenzyme A are present in autotrophically grown cells of C. thiosulfatophilum and R. rubrum. This supports the view that a reaction sequence catalyzing the conversion of α-ketoglutarate into oxaloacetate is unlikely to exist in these bacteria.

1. Acid phosphatase (AcPase) and alkaline phosphatase (AlPase) activities and specific activities were determined in six different tissues of Uromastix during active and hibernating periods. 2. The protein concentration was significantly reduced in all the tissues during hibernation. 3. pH optima of acid and alkaline Pases were found to be 4.2 and 9.2 respectively. 4. AcPase activity was increased in all the tissues except liver and small intestine during hibernation. 5. AlPase activity was increased in all the tissues except small intestine during hibernation. 6. Specific activities of both the enzymes were increased during hibernation.

Esterases, acetylcholinesterase and cholinesterase activities were determined in various tissues of Uromastix hardwickkii during hibernation and activity. 1. The protein concentration was significantly reduced during hibernation. 2. The esterase activity in all the tissues was found to be significantly reduced during hibernation. 3. Acetylcholinesterase activity was significantly increased in all the tissues. 4. There was no significant difference in the cholinesterase activity duriing the two periods. 5. The specific activities of all the enzymes were found to be significantly increased during hibernation.

The cytoplasmatic fraction of rat liver contains both 17 β-hydroxysteroid-oxidoreductase and a “transhydrogenase-activity”, which catalyses the transfer of hydrogen from the 17 β-position of estradiol-17 β to the 17-position of 4-androstene-3,17-dione. The 17 β-hydroxysteroid-oxidoreductase was purified 718-fold and the “transhydrogenase-activity” 264-fold by ammonium sulphate precipitation, gel chromatography with Sephadex G-200, column chromatography on DEAE-Sephadex and isoelectric focusing. The two enzymic activities could not be separated. The characteristics of the two enzymatic activities give some evidence that the “transhydrogenase-activity” is identical with the already known 17 β-hydroxysteroid-oxidoreductase. Isoelectric focusing of the chromatographycally enriched 17 β-enzyme gave an isoelectric point at 5,2. The 17 β-enzyme has a molecular weight of 62 — 65 000 as determined by mobility on Sephadex G-200 superfine. The kinetic constants for both the 17 β-enzyme and the “transhydrogenase-activity” were determined.

The effect of ethidium bromide (EB) on the synthesis of circular DNA of mammalian cells was studied by isopycnic centrifugation in a CsCl-EB solution. EB (0.1—0.5 μg/ml) interferes with the synthesis of newly-formed circular DNA of HeLa cell mitochondria and causes degradation of the pre-existing circular DNA, as well. Under the same conditions, nuclear DNA synthesis was not inhibited. This effect was not reversible at a concentration of 0.5 μg EB/ml or more. Cytosine arabinoside (ara-C) did not exhibit an effect similar to that of EB.

We investigated in vivo labelling of DNA in single organs of female Wistar rats after application of 3 H-methionine. In 40 g and 120 g rats the tritium incorporation into DNA was 10 times higher in spleen than in liver, kidney and heart. DNA methylation in newborn rats (6 — 8 g) was more pronounced in each of these organs. We demonstrated a varying degree of tritium incorporation into the different bases of DNA depending on the organs. We claim that only the values for 5-methylcytosine should be used as sole criteria of DNA methylation. Our results indi cate that DNA methylation in vivo is enhanced in those organs, where a more intensive DNA synthesis occurs.

Potassium measurements were carried out continuously with a potassiumselective electrode of the ORION type by compensation of the uptake of starved bacteria. The output of H + -ions was simultaneously registered by a pH-stat. Addition of either glucose, pyruvate or lactate triggers different iontransport velocities across the bacterial membrane. K + obeys saturation kinetics not only referring to the external concentration of K + , but also with respect to the concentration of lactate and the same applies to the velocity of the extruded He-ions referring only to lactate. It could be demonstrated that an exchange for H + -ions is not an indispensable condition for the uptake of K + -ions by E. coli.