bluuebunny/crossref_metadata_2025 huggingface dataset:
Species-Specific Differences in Acetyl Coenzyme A Synthesis of Chloroplasts
Authors: Treede Hans-Jürgen , Riens Burgi , Heise Klaus-Peter
Published: August 2018

Acetyl-CoA and Fatty Acid Synthesis, Chloroplasts The present investigation indicates that photosynthetically active chloroplasts can synthesize acetyl-CoA either from acetate via acetyl-CoA synthetase (ACS) or from pyruvate via the pyru­ vate dehydrogenase complex (PDC). Both enzyme systems have been assayed in rapidly prepared extracts of chloroplasts isolated from spinach, peas and maize mesophyll. Their kinetic properties showed few species-specific differences. The differing pyruvate and acetate concentrations within the corresponding leaf tissues have been interpreted, therefore, as constituting a major factor determining the relative involvement of both acetyl-CoA synthesizing systems within the different types of chloroplasts. The idea that acetate originates from mitochondria and pyruvate from the cytosol has been supported by nonaqueous fractionation studies. Diffusion-mediated faster up­ take of acetate may indicate a predominant role of the ACS in spinach chloroplasts. Higher cellular pyruvate/acetate-ratios (2-5) in pea and maize leaves may enhance pyruvate uptake into chloroplasts and thus PDC-driven acetyl-CoA synthesis in pea and maize mesophyll chloroplasts. Maize mesophyll chloroplasts even show a light-driven pyruvate uptake accompanied by a stimulated acetyl-CoA and fatty acid formation. Assuming light-dependent increasing parameters in the stroma space, like Mg2+-concentrations, pH and ATP, as further control criteria in chloroplast acetyl-CoA formation, the ACS appears better adapted to the circumstances in illuminated chloroplasts because of the fact that 1. the ACS requires these cofactors altogether; 2. the PDC is stimulated by increasing pH (up to 8) and Mg-levels (up to 5 mᴍ) alone.
Acyclo Nucleosides and Nucleotides: Synthesis, Conformation and Other Properties, and Behaviour in Some Enzyme Systems, of 2′,3′-Seco Purine Nucleosides, Nucleotides and 3′:5′-Cyclic Phosphates, Analogues of cAMP and cGMP
Authors: Stolarski Ryszard , Kazimierczuk Zygmunt , Lassota Piotr , Shugar David
Published: August 2018

The 3′:5′-cyclic phosphates of 2′,3′-secoadenosine and guanosine, structural analogues of cAMP and cGMP, were synthesized by cyclization of the 5′-phosphates of 2′,3′-secoadenosine and guanosine, respectively. The 2′,3′-seco-3′:5′-cAMP was converted to the IM P analogue by nitrous acid deamination, and to the 8-bromo analogue by bromination.

Chemical phosphorylation of 2′,3′-secoadenosine gave four products, the major one of which, in 50% yield, was 2′,3′-seco-3′:5′-cAMP, identical to that obtained by the cyclization reaction above. The three other products have been tentatively identified.

The conformations in solution of the seco nucleosides, their 5′-monophosphates, and their 3′:5′-cyclic phosphates, were determined with the aid of 1H , 13C and 31P NMR spectroscopy, particular attention being devoted to orientations about the C-O bonds and the glycosidic bond, and the results compared with crystallographic data available for the 2′,3′-seco congener of ribofuranosyl benzimidazole. The findings are briefly discussed in relation to substrate and inhibitor properties in some enzyme systems.

Some of the foregoing compounds have been examined as potential enzyme substrates and inhibitors. In particular, the seco 3′:5′-cyclic phosphates are resistant to cAMP cyclic phos­ phodiesterase of mammalian origin, but are slowly hydrolyzed by purified higher plant cyclic nucleotide phosphodiesterase to the corresponding monophosphates.
Effect of Tuftsin on the Phagocytotic Activity of the Unicellular Tetrahymena. Does Primary Interaction Develop Imprinting ?
Authors: Csaba G. , László Valéria , Kovács P.
Published: August 2018

The natural mammalian phagocytosis stimulator tetrapeptide tuftsin stimulated also the phagocytosis of the unicellular Tetrahymena. The selectivity of the Tetrahymena was not complete, as threonin-free tuftsin provoked a greater response. Treatment with tuftsin did not develop functional imprinting, however the binding capacity of cell membrane significantly increased after the first treatment.
The Photosynthetic Apparatus of Ectothiorhodospira halochloris 3. Effect of Proteolytic Digestion on the Photoactivity
Authors: Steiner R. , Kalumenos B. , Scheer H.
Published: August 2018

Photsynthetic membranes of Rhodopseudomonas virids and Ectothiorhodospira halochloris were treated with proteinase K. The photochemical activity (light minus dark difference spectra) were compared to the polypeptide composition (SDS-polyacrylamide gel analysis). In E. halo­chloris, difference bands appear at 806 (+), 838 (+) and 854 nm (-) . All three decrease in intensity upon incubation with proteinase K., but this decrease is much slower than the proteolysis of both the reaction center and antenna related polypeptides. Photochemical activity remains high as long as a small part of the RC and two lower molecular weight polypeptides M* (22.0 kDa) and B* (15.3 kDa) are present. The M subunit is the most stable polypeptide in the RC of Rp. viridis too, and the photochemical activity is related to the remainder of this and to the one newly formed polypeptide (15.3 kDa), but doesn’t show the typical absorption shift of the antenna (B 800/1020 → B 800/960). The results are discussed quantitatively and compared to those obtained from Bchl α containing organisms.
Interaction of Sodium, Lithium, Caesium, and Potassium Ions with Ascorbyl Radicals
Authors: Wieczorek Piotr , Ogoński Tadeusz , Machoy Zygmunt
Published: August 2018

The influence of the concentration of sodium, lithium , caesium, and potassium ions as well as of the ionic strength of the solutions used on the dismutation rate of ascorbyl radicals has been investigated. While the dismutation rate was not influenced by Li+, it decreased, however, with increasing concentrations of the other ions investigated. The largest effect was obtained with Na+. This change in dismutation rate indicates a stabilizing effect on ascorbyl radical by these ions.
The Rate of ATP Hydrolysis Catalyzed by Reconstituted CF0F1-Liposomes
Authors: Schmidt Günter , Gräber Peter
Published: August 2018

The conditions for optimal rates of ATP hydrolysis catalyzed by the chloroplast ATP-synthase (ATPase), CF0F1, after isolation and reconstitution into asolectin liposomes have been investi­gated. The rate of ATP hydrolysis was measured either after oxidation of CF0F1 (by incubation with iodosobenzoate) or after reduction of CFoF, (by incubation with dithiothreitol). In both cases a rate of about 1-2 ATP (CF0F1·s)-1 was observed under uncoupled conditions. If the proteoliposomes are first energized by an acid-base transition and a K+ /valinomycin diffusion poten­tial, the uncoupled rate of ATP hydrolysis is about 1-2 ATP (CF0F1 ·s) 1 for the oxidized enzyme and about 20 for the reduced species. This rate is about a factor 2 smaller than that observed in chloroplasts under the same conditions
Chromophore Assignment in C-Phycocyanin from Mastigocladus laminosus
Authors: Siebzehnrübl S. , Fischer R. , Scheer H.
Published: August 2018

C-phycocyanin from the cyanobacterium, Mastigocladus laminosus, and its subunits have been treated with ρ-chloromercuribenzenesulfonate (PCMS). A single reactive site was found on the 13- subunit, and assigned to the single free cystein-β109. The concomitant spectral changes (absorp­tion, fluorescence, circular dichroism), together with the known close proximity of cys-β109 to chromophore β82, allowed an unambiguous assignment of the three spectrally, biochemically and functionally different chromophores to specific binding sites on the two peptide chains (α84: 616-618, β82: 622-624, β153: 598-600 nm).
The Effect of Phosphinothricin (Glufosinate) on Photosynthesis II. The Causes of Inhibition of Photosynthesis
Authors: Sauer Heidrun , Wild Aloysius , Rühle Wolfgang
Published: August 2018

It was shown in the previous study that phosphinothricin (glufosinate) causes an accumulation of ammonia and inhibition of photosynthesis. The extent to which there is a connection between these two processes is now investigated in the present study. First of all. the role of NH3 per se in the impairment of photosynthesis was to be clarified. For this purpose, the inhibition of photosyn­thesis was investigated in relation to exogenously applied ammonia in chloroplasts, protoplasts and entire leaves. The comparison with the experimental results in leaves in which the ammonia was formed endogenously (by action of phosphinothricin) shows that the ammonia toxicity at least cannot be solely responsible for the inhibition of photosynthesis. This is confirmed by the finding that photosynthesis is maintained under non-photorespiratory conditions, although considerable amounts of NH3 are concentrated at the same time in the plants. A process connected with photorespiration appears to play the essential role.

Simultaneous administration of phosphinothricin and glutamine largely prevented the impair­ment of photosynthesis. This indicates that the main cause for the inhibition of photosynthesis by phosphinothricin is based on a depletion of glutamine. Three subsequent reactions which may cause the inhibition of photosynthesis are discussed: 1) an inhibition of protein biosynthesis, 2) a toxic accumulation of glyoxylate in the photorespiratory cycle and 3) a deficiency of intermediates of the Calvin cycle in consequence of the interrupted photorespiration.
Sethoxydim-Uptake by Leaf Slices of Sethoxydim Resistant and Sensitive Grasses
Authors: Struve I. , Golle B. , Lüttge U.
Published: August 2018

Leaf slices of the sethoxydim sensitive grasses Poa pratensis and Festuca ovina and the sethoxy- dim resistant grasses Poa annua and Festuca rubra take up the herbicide at similar rates. Uptake is almost linear with concentration up to 2 mᴍ, independent of light and little affected by tempera­ture between 0 and 25 °C. Uptake is highly pH sensitive. At pH 7.0 rates of uptake are only about 20% of the rates observed at pH 3.5. Time course of uptake suggests a rapid equilibration of the compartments taking up the herbicide within 2 h. It is suggested that sethoxydim uptake by the grass-leaf tissue is a nonspecific process involving passive lipid diffusion and lipid equilibration of the non-dissociated weak acid sethoxydim (pKa = 4.6).
Light-Induced Ca2+ Influx into Spinach Protoplasts
Authors: Heimann Kirsten , Kreimer Georg , Melkonian Michael , Latzko Erwin
Published: August 2018

Protoplasts from spinach leaves exhibit a light-induced Ca2+ influx. The half maximum rate of Ca2+ influx is achieved at ~ 5 Wm-2. The action spectrum of this influx is similar to that of photosynthesis. Furthermore, light-induced Ca2+ influx is abolished by DCMU (≥ 0.5 μᴍ) and is sensitive to the uncoupler FCCP. Vanadate up to 3 μᴍ enhances light-induced Ca2+ influx. These data indicate that photosynthetic electron transport is involved in light-induced Ca2+ influx into spinach protoplasts.
Methanogenesis from Acetate by Methanosarcina barkeri: Catalysis of Acetate Formation from Methyl Iodide, CO2 , and H2 by the Enzyme System Involved
Authors: Laufer Kerstin , Eikmanns Bernhard , Frimmer Ursula , Thauer Rudolf K.
Published: August 2018

Cell suspensions of Methanosarcina barkeri grown on acetate catalyze the formation of methane and CO2 from acetate as well as an isotopic exchange between the carboxyl group of acetate and CO2. Here we report that these cells also mediate the synthesis of acetate from methyl iodide, CO2, and reducing equivalents (H2 or CO), the methyl group of acetate being derived from methyl iodide and the carboxyl group from CO2. Methyl chloride and methyltosylate but not methanol can substitute for methyl iodide in this reaction. Acetate formation from methyl iodide, CO2, and reducing equivalents is coupled with the phosphorylation of ADP. Evidence is pres­ented that methyl iodide is incorporated into the methyl group of acetate via a methyl corrinoid intermediate (deduced from inhibition experiments with propyl iodide) and that CO2 is assimi­lated into the carboxyl group via a C1 intermediate which does not exchange with free formate or free CO. The effects of protonophores, of the proton-translocating ATPase inhibitor N.N′-di- cyclohexylcarbodiimide, and of arsenate on acetate formation are interpreted to indicate that the reduction of CO2 to the oxidation level of the carboxyl group of acetate requires the presence of an electrochemical proton potential and that acetyl-CoA or acetyl-phosphate rather than free acetate is the immediate product of the condensation reaction. These results are discussed with respect to the mechanism of methanogenesis from acetate.
Steric Course of the Rhodium-Catalyzed Decarbonylation of Chiral 4-M ethyl-[1-3H,2-2H1]pentanal
Authors: Otsuka Hideaki , Floss Heinz G.
Published: August 2018

(R)-and S)-4-methyl-[1-3H,2-2H1]pentanal were prepared from l -and D-leucine via leucic acid and (S)-and (R)-4-methyl-[2-2H1]pentanoic acid. Decarbonylation of these samples with tris-(triphenylphosphine)rhodium chloride followed by Kuhn-Roth oxidation of the resulting 2-methylbutane gave chiral acetic acid of 35% e.e. S and 31% e.e. R configuration, respectively. The decarbonylation reaction thus proceeds with net retention of configuration, possibly accom­panied by some racemization.
Epicuticular Wax Hydrocarbons of Ericaceae in Germany
Authors: Salasoo Inno
Published: August 2018

Alkane distribution patterns were determined in the epicuticular wax of 7 species of Ericaceae, including 5 species from more than one location. Results showed good agreement between sam­ples of any given species from different locations; thus any differences in environmental condi­tions including altitude were insufficient to affect the alkane patterns. Average chain length was highest in Calluna vulgaris and lowest in Vaccinium uliginosum.
Sn-Glycerol-3-phosphate is a Product of Starch Degradation in Isolated Chloroplasts from Chlamydomonas reinhardii
Authors: Klöck Gerd , Kreuzberg Karlheinz
Published: August 2018

Sn-glycerol-3-phosphate Sn-glycerol-3-phosphate accumulates during starch catabolism by intact isolated chloroplasts from Chlamydomonas reinhardii in the dark. Further products detected mainly were 3-phospho-glyceric acid and triose phosphates with a ratio between 3-phosphoglyceric acid, sn-glycerol-3-phosphate and triose phosphates of 1.0:0.9:0.2. The production of sn-glycerol-3-phosphate by a plastidic glycerol-3-phosphate dehydrogenase provides a reasonable mechanism for regenerating reducing equivalents during continuous starch breakdown in the chloroplast of the alga C. reinhardii.
Identification of Three Sex Pheromone Components of the Female Saturniid Moth Antheraea pernyi (Lepidoptera: Saturniidae)
Authors: Bestmann Hans-Jürgen , Attygalle Athula B. , Brosche Thorolf , Erler Joachim , Platz Hans , Schwarz Jürgen , Vostrowsky Otto , Cai-Hong Wu , Kaissling Karl Ernst , Te-Ming Chen
Published: August 2018

By means of electroantennography and single cell recordings, GC and GCMS analyses and GC analysis with EAG detection (6E,11 Z)-6,11-hexadecadienal, (6E,11 Z)-6,11-hexadecadienyl acetate and (4E,9Z)-4,9-tetradecadienyl acetate were identified as the primary components of the sex pheromone of female Antheraea pernyi (Lepidoptera: Saturniidae).
A Fungal Metabolite as the Male Wing Gland Pheromone of the Bumble-Bee Wax Moth, Aphomia sociella L.
Authors: Kunesch Gerhard , Zagatti Pierre , Pouvreau André , Cassini Renée
Published: August 2018

3,4-Dihydro-9-hydroxy-3-methylisocoumarin [R(-)-mellein] was identified as the major component of the male wing gland pheromone of the bumble-bee wax moth, Aphomia sociella L. (Pyralidae, Galleriinae). The presence of Aspergillus ochraceus Wilhelm, a mellein producing microorganism, was detected in the intestines of last-instar larvae and in bumble-bee nests. Arguments for a new type of insect-fungus relationship are presented.
The Topology of the 32 kDa Herbicide Binding Protein of Photosystem II in the Thylakoid Membrane
Authors: Kleier D. A. , Andrea T. A. , Hegedus J. K. J. , Gardner G. M. , Cohen B.
Published: August 2018

The 32 kDa herbicide binding protein is a membrane bound protein which is implicated in the binding of many photosystem II herbicides as well as in the binding of the endogenous quinone OB which serves as the secondary electron acceptor on the reducing side of photosystem II. The topology of the 32 kDa protein has been predicted using a combination of hydrophobic moment analysis, membrane propensity analysis and empirical secondary structure predictions. Our model consists of five transmembrane helices. The loop connecting the fourth and fifth transmembrane helices is thought to form part of the herbicide binding site. Our analysis suggests that this loop also contains a helical segment which may seek the surface of the membrane by virtue of its relatively high hydrophobic moment. Our topology is compared with several others which have been proposed in the literature as well as with the topology of the L and M proteins of the bacterial reaction center of R. viridis. The significance of mutagenesis and photo-affinity labeling experiments is also discussed in terms of our model.
The Use of HPLC for the Purification of the Qв-Protein
Authors: Wildner Günter F. , Fiebig Claudia , Dedner Norbert , Meyer H. E.
Published: August 2018

The Qв-protein is as a hydrophobic integral membrane protein firmly bound in the reaction center complex of photosystem II. A new method was developed to purify the SDS extracted protein using reversed-phase chromatography with two binary linear gradient systems. The identification of the Qв-protein was achieved by its rapidly labeling during photoassimilation of [35S]sulfate and by its reaction with the photoaffinity label azido-[14C]atrazine. Furtherm ore, antisera against the purified Qв-protein reacted with a single peak fraction, the second peak of the chrom atogram , which was identical with the labeled protein peak fraction.
Triazine Resistance in Phalaris paradoxa: Physiological and Molecular Analyses
Authors: Schönfeld Mordechay , Yaacoby Tuvia , Ben-Yehuda Adi , Rubin Baruch , Hirschberg Joseph
Published: August 2018

Triazine resistance in a mutant biotype of Phalaris paradoxa is accompanied by changes in the chlorophyll fluorescence induction curve, and by reduced quantum yield for electron transport, indicating altered photosystem II activity. However, light-saturated rates of electron transport in isolated chloroplasts, rates of CO2 uptake in leaves and dry weight production of the triazine resistant biotype, are equal or superior to those of the wild type. A single mutation in the psbA gene, leading to a serine to glycine shift at position 264 of the thylakoid membrane 32 kDa Qв- protein. was found in the herbicide resistant mutant. The results indicate that triazine resistance is not necessarily linked to inferior photosynthetic and growth performance.
X-Ray Structure Analysis and Spectroscopic Data of the Antibiotic 8-(Dichloroacetyl)-5-hydroxy-2,7-dimethyl-1,4-naphthoquinone from the Fungus Mollisia sp.*
Authors: Weber Gabriela , Hübner Thomas , Gieren Alfred , Sonnenbichler Johann , Kowalski Tadeusz , Holdenrieder Ottmar
Published: August 2018

Mass spectra, X-ray data and high resolution 13C and 1H NMR spectra of 8-(dichloroacetyl)-5-hydroxy-2,7-dim ethyl-1,4-naphthoquinone are reported. The antibiotic active com pound was isolated from the fungus Mollisia sp.
Transformationen von trans-2-Hexenal durch Botrytis cinerea PERS. als Entgiftungsmechanismen / Transformations of trans-2-Hexenal by Botrytis cinerea PERS. as Detoxification Mechanisms
Authors: Urbasch Irene
Published: August 2018

The metabolization of trans-2-hexenal - one of the main components of plant wound gases with antibiotic activity - was investigated for 5 different isolates of Botrytis cinerea PERS. The transformation products as well as the kinetics of their formation were analyzed.

Isolates exclusively mycelium forming (Bc 1 and Bc 13) transformed tr-2-hexenal into tr-2- hexenol, while sporulating isolates (Bc 3, Bc 9 and Bc 10) converted tr-2-hexenal to hexanol-1.

Basically the metabolization of tr-2-hexenal proceeded in the same way via the aqueous phase as in the gas phase.

The transformation products tr-2-hexenol and hexanol-1 showed significantly lower toxicity against the tested B. cinerea isolates than tr-2-hexenal. In each isolate the end product of tr-2- hexenal conversion had the weakest inhibitory activity. The transformation reactions thus represent detoxification mechanisms for these fungi.
Investigation of the Screening Pigment System in the Compound Eye of the Moth Agrotis segetum (fam. Noctuidae) by Visible Reflectometry
Authors: Nordtug Trond , Melø Thor Bernt
Published: August 2018

The functional properties of the light adaptation system in the superposition eye of the moth Agrotis segetum have been investigated by reflection spectroscopy. The spectrum of the reflected light from the tapetum of dark adapted eyes had a peak at about 580 nm corresponding to a spacing between the reflecting layers in the tapetum of 145 nm. During light adaptation of the eye the observed reflectance changes could be explained by light extinction in one screening pigment. The shape of the extinction spectrum of the screening was constant throughout the adaptation process and after a lag phase the optical density of the pigment in the light path increased linearly with time. The screening pigment caused light extinction both by absorption and to some degree also by scattering. The absorption spectrum of the screening pigment had a broad maximum about 590 nm and the scattering efficiency of the pigment particles seemed to be nearly independent of the wavelength.
Partial Lack of N-Acetyl Substitution of Glucosamine in the Peptidoglycan of the Budding Phototrophic Rhodomicrobium vannielii
Authors: Jürgens Uwe J. , Rieth Baldur , Weckesser Jürgen , Dow Crawford S. , König Wilfried A.
Published: August 2018

The rigid layer and peptidoglycan fractions from two strains (ATCC 17100 and Rm 5) of the budding phototrophic Rhodomicrobium vannielii were isolated. Rigid layers of both strains contain protein in addition to peptidoglycan. They were free of polysaccharides and fatty acids. The respective peptidoglycan fractions contain glucosamine, muramic acid, ʟ-and ᴅ-alanine, ᴅ-glutamic and meso-diaminopimelic acid in approximately equimolar ratios except for a signifi­ cant lower relative ᴅ-alanine content. Analysis of partial acid hydrolysates revealed A 1 γ-type structure of Rhodomicrobium vannielii peptidoglycan (shown with strain ATCC 17100). An about 10-30% lack of N-acetylation of glucosamine was indicated. The degree of cross-linkage was found to be about 60% .

No differences in peptidoglycan composition and degree of cross-linkage were found between swarmer-and chain-cells as examined with strain Rm 5.
Accumulation of Phenolic Compounds and Phytoalexins in Sliced and Elicitor-Treated Cotyledons of Cicer arietinum L.
Authors: Jaques Ulrike , Keßmann Helmut , Barz Wolfgang
Published: August 2018

Upon slicing cotyledons of chickpea, Cicer arietinum L.. accumulate the pterocarpan phyto­alexins medicarpin and maackiain. Treatment of this tissue with an elicitor from the phytopathogcnic deuteromyccte Ascochyta rabiei (Pass.) Lab. greatly enhances accumulation of the pterocarpans and of other isoflavones and flavonoids. Isolation, chromatographic purification and structural elucidation by spectroscopic techniques of 16 phenolic compounds is described. Cotyledons induced for phytoalexin biosynthesis readily accumulate the isoflavones daidzein, formononetin, calycosin and pseudobaptigenin which are thought to be intermediates in pterocarpan formation.
Benzofuroxan as Electron Acceptor at Photosystem I
Authors: Lotina-Hennsen B. , Garcia A . , Aguilar M. , Albores M.
Published: August 2018

The midpoint potential of BFO, the sensitivity of its photoreduction to DCM, DBMIB and KCN, and the photosystem I activity, suggest that the photoreduction of BFO in the chloroplast is at the primary electron acceptor x of photosystem I. and is irreversible.

Rates of electron transport are similar in basal phosphorylating or uncoupled conditions al­though electron transport is coupled to photophosphorylation.
Synthesis of Piperoyl Coenzyme A Thioester
Authors: Semler Ursula , Schmidtberg Gunter , Gross Georg G.
Published: August 2018

Piperoyl-CoA, a potential intermediate in the biosynthesis of piperine. the pungent principle of pepper, was synthesized via N-succinimidyl piperate and subsequent transesterification with CoA- SH. UV-spectrophotometry of the HPLC-purified compound revealed, besides a maximum at 260 nm, a pronounced second absorption maximum at 368 nm due to the thioester linkage for which, as determined via the Fe3+-complex of piperoyl hydroxamate and with [14C]piperoyl-CoA, a molar extinction coefficient of 30.8 × 106 [cn2mol-1] was calculated.
Small Angle X-Ray Study on the Structure of Active and Inactive Ribulose-1,5-bisphosphate Carboxylase-Oxygenase from Spinach. Evidence for a Configurational Change
Authors: Pilz Ingrid , Schwarz Erika , Pal Gour P. , Saenger Wolfram
Published: August 2018

Small angle X-ray scattering studies on ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) from spinach reveal a configurational change in its quaternary structure upon the transition of the molecule from the activated form occurring in the presence of CO2 and Mg2+ to the deactivated form obtained when CO2 and Mg2+ are removed by extensive dialysis under nitrogen. Present structural models are comparable to models which were postulated previously for the same enzyme but isolated from the hydrogen bacterium Alcaligenes eutrophus [O. Meisen- berger, I. Pilz, B. Bowien, G. P. Pal, and W. Saenger, J. Biol. Chem. 259, 4463-4465 (1984)]. The radius of gyration is R = 47.5 ±0.2 nm for the active spinach Rubisco. Upon deactivation, R changes to 49.2 ± 0.2 nm, suggesting a more elongated quaternary structure. The observed differ­ence in deactivation behaviour in ambient and in nitrogen atmosphere indicates a higher affinity of this spinach enzyme to CO2 with respect to the same enzyme from Alcaligenes eutrophus.
In vitro T1-und T2-Relaxationszeiten von gerinnendem Blut und Thromben / In vitro T1 and T2 Relaxation Times of Coagulating Blood and Thrombuses
Authors: Landler U. M. , Hergan K. , Justich E. , Sterk H.
Published: August 2018

A comparison between blood and thrombuses is made on behalf of T1 and T2 relaxation data. Thereby, the time interval between the withdrawal and the measurement of blood forms a parameter of investigation. Among the thrombuses the surgically removed ones are compared with those aggregated in blood during course of time. As the most outstanding result one can see that the formation of thrombuses changes significantly the T1 and T2 relaxation times of 1H und 23Na. The values of the relaxation times obtained for those thrombuses which have aggregated within the blood are thereby comparable with those relaxation times found for the surgically removed ones.
Epicuticular wax of euphorbia aphylla brouss. ex. willd., euphorbiaceae
Authors: Gülz Paul-Gerhard , Bodden Jutta , Müller Edith , Marner Franz-Josef
Published: August 2018

Quantity and composition of epicuticular wax of Euphorbia aphylla were examined. The wax contained the common lipid components n-alkanes, wax esters, pr. alcohols, fatty acids and in traces aldehydes and acetates all occurring in homologous series. Additionally, several triterpenols such as β-amyrin, α-amyrin, lupeol and simiarenol were found. With the exception of simiarenol these triterpenols occurred free as well as esterified with acetic acid and fatty acids. The ketones, oleanen-3-one, ursen-3-one and lupen-3-one have also been identified
Novel sesquiterpene ethers from liquid cultures of the wood-rotting fungus lentinus lepideus
Authors: Abraham Wolf-Rainer , Hanssen Hans-Peter , Möhringer Claudius
Published: August 2018

The brown-rot fungus Lentinus lepideus (Fr.: Fr.) Fr. FPRL 7B (Basidiomycotina) was cultivated on a defined synthetic liquid medium containing glucose (2%), isoleucine (0.15%), and mineral salts for 105 days. The steam distillate was separated by column chromatography. Three novel sesquiterpene ethers with muurolane skeleton (lentideusether, isolentideusether, and 10-hydroxylentideusether) were isolated and their structures elucidated by spectroscopic methods, in particular by 1H NMR spectra and by two-dimensional 1H/1H- and 13C/1H-chemical shift correlation. These compounds are described for the first time as natural products. As a further metabolite, the acyclic sesquiterpene alcohol terrestrol was identified
Volatile compounds from androconial organs of danaine and ithomiine butterflies
Authors: Schulz S. , Francke W. , Edgar J. , Schneider D.
Published: August 2018

Pyrrolizidine alkaloid derivatives are present in the androconial (male scent) organs of Prittwitzia hymenaea, Mechanitis isthmia veritabilis, Tithorea harmónia fúria (Lep., Ithomiinae), Amauris echeria and Euploea sylvester (Lep., Danainae). While the ithomiines contain the new pyrrolizidine alkaloid derivative methyl hydroxydanaidoate, the danaines contain the known derivatives danaidone and hydroxydanaidal. In addition, 2,2,6-trimethyl-2-cyclohexen-1,4-dione (oxoisophorone) and related terpenoids have been identified from Amauris, Euploea and Prittwitzia as well as from the flowers of Buddleja davidii (Loganiaceae). Three new naturally occurring bishomoterpenes as well as mono- and sesquiterpenes and aromatic compounds add to the formation of species specific blends in the scent organs of the butterflies
On the release and action of the hypertrehalosaemic hormone from the cockroach nauphoeta cinerea
Authors: Gäde Gerd
Published: August 2018

The corpora cardiaca of the cockroach Nauphoeta cinerea contain a hypertrehalosaemic hormone (HTH) which is chemically characterized as a blocked decapeptide. The synthetic HTH shows the same chromatographic behaviour as the material isolated from corpora cardiaca. The synthetic peptide causes hypertrehalosaemia and fat body glycogen phosphorylase-activation in N. cinerea as well as in the American cockroach, Periplaneta americana in a dose-dependent fashion. It is calculated that one gland from N. cinerea stores about 50 pmol of HTH. Roughly 10% of the total available hormone in the gland is released in vitro during exposure to an elevated potassium saline which causes depolarization of the neurosecretory cells
Kinetic Relationship between Energy-Dependent Fluorescence Quenching, Light Scattering, Chlorophyll Luminescence and Proton Pumping in Intact Leaves
Authors: Bilger W. , Heber U. , Schreiber U.
Published: August 2018

A measuring system was designed for simultaneous recording of modulated chlorophyll fluorescence and light scattering changes. The kinetic relationship was investigated between lightinduced changes in non-photochemical fluorescence quenching, as determined by the saturation pulse method, and in light scattering, as measured via the apparent absorbance change at 543 nm. Very similar, but not identical kinetics were observed, reflecting a close non-linear relationship between these two indicators of thylakoid membrane energization. Fluorescence was found more sensitive at low levels of energization, while scattering continued indicating further increases in energization when quenching already was saturated. A general relationship between quenching and scattering is demonstrated which holds irrespective of whether energization is varied during induction or via changes in light intensity or CO2 concentration. In the light-off responses, only part of fluorescence quenching was found to relax with the same kinetics as scattering. It is suggested that at high levels of energization slowly reversible membrane changes may be induced which have the potential of non-photochemical quenching at a low level of energization, and which are not accompanied by scattering changes. Neither quenching nor scattering changes displayed kinetics sufficiently fast to be taken as a direct expression of internal thylakoid acidificati on in intact leaves. This conclusion is drawn from comparative measurements of proton-uptake, as reflected by CO2-solubilization upon light-induced stroma alkalization, and of chlorophyll luminescence. Both, the initial CO2 - gulp and the pH-dependent luminescence rise were found to clearly precede the development of energy-dependent quenching.
Azadirachtin-Induced Sterilization in Mature Females of Rhodnius prolixus
Authors: Feder Denise , Valle Denise , Rembold H. , Garcia E. S.
Published: August 2018

The effects of azadiraehtin A , given orally, on the reproduction of mature females of Rhodnius prolixus were studied. Azadiraehtin A caused a reduction in oocyte growth and consequently in the egg production in a dose-dependent manner. Eggs layed had no alteration in their viabilities. A significant correlation between these effects and the titers of both vitellogenin in the haemolymph and vitellin in the ovaries was observed. Ecdysteroid titers in haemolymph and ovaries, as determined by radioimmunoassay, were decreased by this treatment. In vitro analysis suggested that azadiraehtin may directly interfere in ovarian ecdysteroid production. The significance of these findings in relation to the mode of action of azadiraehtin is discussed.
Identification of Major Lipids from the Scent Gland Secretions of DumeriFs Ground Boa (Acrantophis dumerili Jan) by Gas Chromatography-Mass Spectrometry
Authors: Simpson John T. , Weldon Paul J. , Sharp Thomas R.
Published: August 2018

The scent gland secretions of Dumeril’s ground boa (Acrantophis dumerili), pooled from two adult males and a female, were analyzed by gas chromatography-mass spectrometry. 2-Hydroxypropanoic acid, hexadecanoic acid, as-9-octadecenoic acid, octadecanoic acid, cholesterol, and 5-cholesten-3-one were indicated. These results are compared with those obtained in analyses of the scent gland secretions of other snakes.
Pressure Effects on the Interactions of the Sarcoplasmic Reticulum Calcium Transport Enzyme with Calcium and Dinitrophenyl Phosphate
Authors: Hasselbach Wilhelm
Published: August 2018

The effect of hydrostatic pressure on the calcium-dependent hydrolysis of dinitrophenyl phosphate by the sarcoplasmic calcium transport enzyme has been studied. The magnesium dinitrophenyl phosphate complex is the true substrate of the enzyme (K - 7000 M-1) by which it is hydrolyzed at 20 °C with a turnover rate of 4 s-1 . Activation by calcium ions occurs between 0.1 and 1 μM as observed for ATP hydrolysis. The activation volume of the enzyme saturated with both ligands exhibits pronounced pressure-dependence, rising from 25 ml/mol at atmospheric pressure to 80 ml/mol at 100 MPa. The apparent binding volumes for magnesium dinitrophenyl phosphate and calcium are likewise pressure-dependent. The volume changes connected with the binding of magnesium dinitrophenyl phosphate is quite small approaching zero at 100 MPa. The apparent binding volume for calcium greatly increases with pressure from 35 ml/mol at atmospheric pressure to 150 ml/mol at 70 MPa. A nearly constant binding volume of approximately 40 ml/mol results if the effect of pressure on the respective rate constants that contribute to the apparent binding constant, is taken into account. The pressure-dependence of enzyme activity at subsaturating calcium concentrations yields an activation volume of 250 ml/mol related to the rate of calcium binding indicating the occurrence of a transient large volume expansion of the enzyme complex. The volume changes observed for the calcium-dependent interaction of the enzyme with magnesium dinitrophenyl phosphate well agree with that found for magnesium p-nitrophenyl phosphate (W. Hasselbach and L. Stephan, Z. Naturforsch. 42c, 641-652 (1987)) indicating that the found volume changes are intrinsic properties of the transport enzyme, independent of the respective energy donor.
Epicuticular Leaf Waxes of Tilia tomentosa Moench. and Tilia × europaea L., Tiliaceae
Authors: Gülz Paul-Gerhard , Müller Edith , Moog Brigitte
Published: August 2018

Quantity and composition of epicuticular leaf wax of Tilia tomentosa Moench. and T. × europaea L. were examined and showed similar wax compositions. The waxes of these two Tilia species contained homologous series of n-alkanes, wax esters, aldehydes, acetates, primary alcohols and fatty acids. In addition to these common epicuticular wax constituents, the triterpenol β-amyrin was found free as well as esterified with long chain fatty acids and in very high amounts with acetic acid in both Tilia species.
Dynamics of the Tissue-Specific Metabolism of Luteolin Glucuronides in the Mesophyll of Rye Primary Leaves (Secale cereale)
Authors: Schulz Margot , Weissenböck Gottfried
Published: August 2018

Developing primary leaves of Secale cereale L. exhibit a dynamic metabolism of the major flavonoid luteolin 7-O-[β-ᴅ-glucuronosyl(1→2)β-ᴅ-glucuronide]-4′-O-β-ᴅ-glucuronide (R1). Final steps of R, biosynthesis are sequential glucuronidations of luteolin, which are catalyzed by three specific UDP-glucuronate: flavone glucuronosyltransferases. These enzymes reach highest activities at the fourth and fifth day of leaf development, coinciding with maximal R, accumulation. The activities decrease with advancing age of the leaves. In contrast, a R1-specific β-glucuronidase, responsible for the hydrolysis of glucuronic acid in position 4′, shows increasing activity up to the 5th or 6th day; but this activity, leading to luteolin 7-O-diglucuronide (R2), is not reduced in later developmental stages. In this phase of leaf development, the amount of R, drastically drops, whereas R2 accumulates only slightly. From in vitro results and from feeding experiments using [14C]cinnamic acid, a precursor of R, biosynthesis, we conclude that the anabolic sequential glucuronidation takes place in young and expanding leaf tissue, whereas deglucuronidation occurs in nearly mature and mature tissue. The three glucuronosyltransferases as well as the β-glucuronidase, and the flavonoids R1 and R2 are localized in the mesophyll.
Effect of Inhalation Anesthetics on Spin-Labeled Cholesterol Containing DPPC Vesicles
Authors: Gulfo N. , Bartucci R. , Sportelli L.
Published: August 2018

We have investigated by means of electron spin resonance (ESR) spectroscopy the influence of three inhalation anesthetics, i.e. halothane, chloroform and diethyl ether, on the interfacial and hydrophobic region as well of 38 mol% cholesterol containing DPPC unilamellar vesicles.

The study has been carried out in the temperature range 25-45 °C. The variation of the order parameter, S, vs temperature of the lipid phase indicates that with this content of cholesterol the characteristic gel → liquid crystalline main phase transition of DPPC, normally occurring at Tt ~ 41 °C, disappears.

When halothane and chloroform are added to the vesicles suspension up to [DPPC]/[anesthetic] molar ratio of 1:1 the main phase transition, as detected with the stearic acid spin label I(12,3), reappears again and it results down shifted at Tt ~ 35 and 39 °C, respectively.

In presence of diethyl ether, instead, the main phase transition is not observable also at the highest concentration of anesthetic used.

Moreover, halothane and chloroform affect similarly the hydrophobic core of cholesterol-!- DPPC vesicles which, in turn, results to be different from the action exerted by diethyl ether in the same region.

The ESR findings are discussed in terms of competitive effects shown by cholesterol and inhalation anesthetics. Moreover, the interfacial region of CHOL + DPPC vesicles results to be the target of anesthetics.
Investigation of Ribulose-1,5-bisphosphate Carboxylase-Oxygenase from Tobacco by Small Angle X-Ray Scattering: A Structural Model for the Enzyme in Solution
Authors: Abuja P. M. , Pilz I.
Published: August 2018

The quaternary structure of ribulose-1,5-bisphosphate carboxylase/oxygenase from tobacco (Nicotiana tabacum) was investigated in solution by means of small angle X-ray scattering. The most important molecular parameters as the radius of gyration (Rg) and the maximum diameter (Dmax) were determined. Both the active and the inactive form of the enzyme were measured at 5 °C and at 20 °C. A more distinct difference in size could be detected between the inactive forms at these two temperatures (Rg = 4.80 nm (5 °C) and 4.68 nm (20 °C)) than between the active forms (Rg = 4.73 nm and 4.69 nm). The maximum diameters were determined to be 13.1 nm for the inactive form at 5 °C and 12.8 nm for the other forms.

A model is proposed consisting of eight large and eight small subunits arranged in the way that seems to be typical for this enzyme in higher plants.
Deoxyribonucleotide Biosynthesis in Green Algae. S Phase-Specific Thymidylate Kinase and Unspecific Nucleoside Diphosphate Kinase in Scenedesmus obliquus
Authors: Klein Beate , Follmann Hartmut
Published: August 2018

NDP kinase and thymidylate kinase are essential for DNA precursor formation in that they phosphorylate the products of de novo deoxyribonucleotide biosynthesis, deoxyribonucleoside 5′-diphosphates and thymidine 5′-monophosphate to the corresponding triphosphates which then serve as DNA polymerase substrates. The two enzymes have been measured in synchronous cultures of the green algae, S. obliquus. Thymidylate kinase exhibits an activity peak at the 11 -12th hour of the 24-hour cell cycle, coinciding with DNA synthesis. Enzyme activity is markedly stimulated in presence of fluorodeoxyuridine in the culture medium. This behaviour of dTMP kinase is very similar to that of three other S phase-specific peak enzymes previously analyzed in synchronous algae, viz. ribonucleotide reductase, thymidylate synthase, and dihydrofolate reductase. In contrast, NDP kinase exhibits high and constant activity through the entire cell cycle. The two kinases have been isolated from cell-free extracts, and separated from each other by chromatography on Blue Sepharose. The peak enzyme, dTMP kinase, has been purified to near homogeneity and its catalytic properties are described; the molecular weight is 56,000. NDP kinase activity is separable into two enzyme fractions, both of molecular weight 100,000 (or higher), which are unspecific with respect to ribonucleotide and deoxyribonucleotide substrates. Characterization and purification of the whole series of deoxyribonucleotide-synthesizing enzymes from one organism provides a basis for in vitro experiments towards reconstitution of an S phase-specific DNA precursor/DNA replication multienzyme aggregate.
The 9-kDa Phosphoprotein Involved in Photoinhibition
Authors: Kuhn Matthias , Thiel Andreas , Böger Peter
Published: August 2018

Photosystem-II particles exhibit strong photoinhibition. Short-term illumination of photosystem- II particles with high-intensity light (5000 μE/m2 × s) leads to a typical change of the protein pattern on SDS-PAGE. Two proteins are mainly affected, namely the well-described 32-kDa herbicide-binding protein which probably is degraded [1] and, first published here, the 9-kDa phosphoprotein, whose function in the PS-II complex is still unknown. This protein is not degraded, but seems to be linked to other polypeptides of the PS-II complex. During light treatment new bands of 23, 41, 50 and 54 kDa appear in the protein pattern of SDS-PAGE.

A monospecific antiserum was produced against the 9-kDa phosphoprotein to investigate its fate. After light treatment the antibodies reacted with new proteins of higher molecular weights, most pronounced with a 23-kDa and a 41-kDa peptide.
The Development of Daffodil Chromoplasts in the Presence of Herbicides SAN 9789 and SAN 9785
Authors: Hloušek-Radojčić A. , Ljubešić N.
Published: August 2018

The effects of two pyridazinone herbicides (SAN 9789 and SAN 9785) were studied on the fine structure and carotenoid composition during the transformation of chloroplasts into chromoplasts in daffodil (Narcissus poëticus L.) flowers. SAN 9789 caused the absence of big characteristic carotene crystals and the appearance of numerous nonosmiophilic plastoglobuli in chromoplasts. The accumulation of all carotenoids was drastically reduced and the content of carotenes was 40-fold lower than in the control. SAN 9785 caused no gross abnormalities in ultrastructure of chromoplasts. The synthesis of carotenes was partially reduced to about 75%. In spite of this the accumulation of xanthophylls is two times higher than in the control. The interaction between chromoplast ultrastructure and carotenoid composition is discussed.
Serological and Structural Comparison of Immunodeficiency Viruses from Man, African Green Monkey, Rhesus Monkey and Sooty Mangabey
Authors: Jurkiewicz E. , Hunsmann G. , Hayami M. , Ohta Y. , Schmitz H.
Published: August 2018

We have studied the serological relationship among the human immunodeficiency virus type 1 (HIV-1), and three simian immunodeficiency viruses (SIV). SIVagm was isolated from African green monkeys (Cercopithecus aethiops), and compared with the previously described isolates of SIVmac from a rhesus macaque (Macaca mulatta) and SIVsm from a sooty mangabey (Cercocebus atys). With respect to the glycoproteins, the simian viruses represent a subgroup apparently different from HIV . To classify HIV and SIV isolates further, we compared tryptic peptide maps of the core polypeptides p18 and p24 of HIV-2, three HIV-1 and five SIV isolates. Each peptide map was distinguishable, and differences are most prominent between the HIV-1 group and the SIVmac/SIVsm group. HIV-2 is very similar to SIVmac and SIVsm. The three SIVagm isolates form a more heterogeneous group. The p24s of all SIVagms are more similar to the p24s of HIV-1, but with respect to p18, one isolate is similar to HIV-1, while the two others are more related to SIVmac, SIVsm, and HIV-2.
Elicitor-induced Changes of Enzyme Activities Related to Isoflavone and Pterocarpan Accumulation in Chickpea (Cicer arietinum L.) Cell Suspension Cultures
Authors: Daniel Susanne , Hinderer Walter , Barz Wolfgang
Published: August 2018

The extractable activities of thirteen enzymes of primary and secondary metabolism have been measured in chickpea (Cicer arietinum L.) cell suspension cultures after treatment with an elicitor from the fungus Ascochyta rabiei (Pass.) Lab. The cell culture, derived from the A. rabiei resistant cultivar ILC 3279, constitutively accumulated the isoflavones biochanin A and formononetin together with their 7-O-glucosides and the 7-O-glucoside-6″-malonates. After elicitor application the cells rapidly form the pterocarpan phytoalexins medicarpin and maackiain.

Among the enzymes of primary metabolism only the glucose 6-phosphate dehydrogenase exhibited a significant increase in activity with a maximum four hours after application of the elicitor. In phenylpropane metabolism the activities of phenylalanine ammonia lyase and chalcone synthase were enhanced by the elicitor and exhibited highest levels after four hours. In contrast the chalcone isomerase activity was not influenced by the elicitor. A substantial enhancement occurred with the isoflavone 7-O-glucosyltransferase activity eight hours after elicitor application.

The results suggest that in this cell culture the elicitor-induced biosynthesis of pterocarpan phytoalexins was accompanied with a rapid and transient increase of those enzyme activities which are located at branching points of related pathways, i.e. pentose phosphate cycle, general phenylpropane metabolism, flavonoid formation and isoflavone conjugation.