bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substrate Flow from Photosynthetic Carbon Metabolism to Chloroplast Isoprenoid Synthesis in Spinach Evidence for a Plastidic Phosphoglycerate Mutase
Authors: Schulze-Siebert Detlef , Heintze Adolf , Schultz Gernot 
Published: August 2018

Abstract
The carbon flow from 3-phosphoglycerate to pyruvate and acetyl-CoA within the chloroplast as well as the pathway for the formation of β-carotene, plastoquinone-9 etc. as plastidic isoprenoids from photosynthetically fixed CO2 hitherto remained unclear because the presence of the phos- phoglycerate mutase in chloroplasts had not unequivocally been proven. To clarify this question, the incorporation of 14CO2, [2-14C]acetate, [2-14C]pyruvate, [2-14C]glycine, [3-14C]serine and [2-14C]mevalonate into β-carotene, plastoquinone-9, sterols and fatty acids was studied using spinach and barley protoplasts and barley seedlings. In protoplasts as well as in seedlings under conditions of CO2 fixation, the largest portion of the acetyl-CoA derived compounds formed was β-carotene and plastoquinone-9 rather than fatty acids and sterols. High rates of fatty acid synthesis were obtained by supplying acetate as well. Mevalonate was incorporated into sterols but not into β-carotene and plastoquinone-9. Direct evidence was obtained for the hitherto questioned plastidic phosphoglycerate mutase. Low activities were found in spinach chloroplasts which were substantiated by the criteria of latency method. Substrate flow from 3-phosphoglycerate to pyruvate via 2-phosphoglycerate and phosphoenolpyruvate was shown by applying [1-14C]- glycerate and following its incorporation. From this the following conclusions were drawn: (i) The plastidic IPP synthesizing system is strongly separated from the cytosolic-ER one. (ii) As the formation of β-carotene and plastoquinone-9 is favoured under conditions of photosynthetic CO2 fixation, a direct carbon flow from 3-phosphoglycerate to isoprenoids via acetyl-CoA by a low- capacity pathway, which shows high affinities for the substrates, is suggested.
Nitrate Reductase from Sphagnum Species: Isolation, in vitro Assays and Partial Purification
Authors: Deising Holger 
Published: August 2018

Nitrate reductase (EC 1.6.6.2) has been isolated from 11 Sphagnum (Bryophyta) species and purified up to 500-fold by a procedure involving (NH4)2SO4 precipitation and blue sepharose affinity chromatography.
The purest fraction showed a nitrate reductase activity of 7.7 nkat mg protein-1 with NADPH as the electron donor. Beside NADPH and NADH, FMNH2 and - after blue sepharose affinity purification of the enzyme - MVH2 were used as electron donors in different assays.
Evolution of E. coli tRNAIle: Evidence of Derivation from Other tRNAs
Authors: Staves Mark P. , Bloch David P. , Lacey James C. 
Published: August 2018

Abstract
Two E. coli tRNAIle sequences were compared against those of 36 other E. coli tRNAs. tRNAIle 1 was found to bear high similarity with tRNAVal 1 (E = 1.11 x 10-18) while tRNAIle 2 had the greatest match ( E = 3 .4 0 x 10-19) with tRNALysl (E is the expected number of such matches, per search, based on coincidence). These matches, which we consider to represent homologies, extend from base 7 to base 67 in the former and base 7 to the end (76) in the latter pair. These results coupled wim otners on tne lower activity ot isoleucine in reactions postulated to be important in primitive protein synthesis (i.e. esterification reactions and non-enzymatic activation by ATP [1-3]) lead us to propose that isoleucine was included among the proteinaceous amino acids, and received its anticodonic assignment, relatively late in evolution through mutation of tRNAs previously employed for other amino acids.
The complete amino acid sequences of the b 800—850 antenna polypeptides from rhodopseudomonas acidophila strain 7750
Authors: Bissig Iwan , Brunisholz René A. , Suter Franz , Cogdell Richard J. , Zuber Herbert 
Published: August 2018

Spectrally pure B 800-850 light harvesting complexes of Rhodopseudomonas acidophila 7750 were prepared by chromatography of LDAO-solubilised photosynthetic membranes on Whatmann DE-52 ion exchange resin. Two low molecular mass polypeptides (α, β) have been isolated by organic solvent extraction of the lyophilised B 800-850 light harvesting complexes. Their primary structures were determined by liquid phase sequencer runs, by the sequence analyses of C-terminal o-iodosobenzoic acid fragments, by hydrazinolysis and by carboxypeptidase degradation.
B 800-850-a consists of 53 amino acids and is 45.3% and 50.9% homologous to the B 800-850- a antenna polypeptides of Rhodobacter sphaeroides and Rhodobacter capsulatus, respectively. The second very short polypeptide (B800-850-β, 41 amino acids) is 61.0% and 56.1% homologous to the corresponding polypeptides of Rb. sphaeroides and Rb. capsulatus. The molar ratio of the two polypeptides is about 1:1. Both polypeptides show a hydrophilic N-terminal domain, a very hydrophobic central domain and a short C-terminal domain. In both polypeptides the typical His residues, identified in all antenna polypeptides of purple nonsulphur bacteria as possible bacteriochlorophyll binding sites, were found
Organ Specific Composition of Epicuticular Waxes of Cistus albidus L., Cistaceae
Authors: Hennig Sabine , Gülz Paul-Gerhard , Hängst Kurt 
Published: August 2018

Abstract
Epicuticular waxes from various organs of Cistus albidus L. showed always an organ specific composition.
Leaf wax contained homologous series of very long chained and saturated wax components, such as hydrocarbons, wax esters, fatty acids and alcohols. Additionally in this wax extract triterpenoids and great amounts of resin were found. Sepal wax had nearly the same wax composition like that of leaves with a trend to shorter chain lengths and not so great amounts of resin.
Petal wax contained the common wax lipids, too, but the homologous series showed a shift to shorter chain lengths, and great amounts of unsaturated lipids were found in hydrocarbons, wax esters and fatty acids. In addition triterpenol esters were found but no resin.
Stamen wax was similar to that of petals. The shift to shorter chain lengths and the presence of great amounts of unsaturated lipids showed a characteristic distribution for stamens.
Seed wax contained only saturated wax lipids. In contrast to leaf waxes, the short chain compounds were dominating, and triterpenoids and resin were missing.
The chemical wax composition of the various organs of C. albidus was correlated to the surface structures of these organs by SEM pictures.
Accumulation of a Novel Red Pigment in Cell Suspension Cultures of Floral Meristem Tissues from Carthamus tinctorius L.
Authors: Saito Koshi , Daimon Etuko , Kusaka Kazuhito , Wakayama Sachio , Sekino Yoshihiro 
Published: August 2018

Abstract
A cell strain originally derived from floral meristem tissues of Carthamus tinctorius (dyer’s saffron) produced substantial amounts of a novel red pigment under controlled culture conditions. The pigment isolated f r om alcoholic extracts of C. tinctorius cultures was compared with authentic carthamin, anthocyanins, betain, and carotenoids. It differed markedly from carthamin and showed none of the characteristic properties of the glycoside or chloride forms of authentic delphinidin, cyanidin, and pelargonidin. Analytic data indicated that this pigment also differs from betanin and from α- and β-carotene. The name “Kurenamin” was tentatively given to this newly isolated red pigment. Effect of the culture media, micro-elements, macro-elements, and putative substrates on the kurenamin production were investigated during cell suspension culture.
Photoinhibition of Electron Transport Activity of Photosystem II in Isolated Thylakoids Studied by Thermoluminescence and Delayed Luminescence
Authors: Vass Imre , Mohanty Narendranath , Demeter Sándor 
Published: August 2018

Abstract
The effect of photoinhibition on the primary (QA) and secondary (QB) quinone acceptors of photosystem I I was investigated in isolated spinach thylakoids by the methods of thermoluminescence and delayed luminescence. The amplitudes of the Q (at about 2 °C) and B (at about 30 °C) thermoluminescence bands which are associated with the recombination of the S2QA
- and S2QB charge pairs, respectively, exhibited parallel decay courses during photoinhibitory treatment. Similarly, the amplitudes of the flash-induced delayed luminescence components ascribed to the recombination of S20A and S2OB charge pairs and having half life-times of about 3 s and 30 s, respectively, declined in parallel with the amplitudes of the corresponding Q and B thermoluminescence bands. The course of inhibition of thermoluminescence and delayed luminescence intensity was parallel with that of the rate of oxygen evolution. The peak positions of the B and Q thermoluminescence bands as well as the half life-times of the corresponding delayed luminescence components were not affected by photoinhibition. These results indicate that in isolated thylakoids neither the amount nor the stability of the reduced OB acceptor is preferentially decreased by photoinhibition. We conclude that either the primary target of photodamage is located before the O b binding site in the reaction center of photosystem II or QA and OB undergo simultaneous damage.
Dark and Photohemolysis of Erythrocytes by Furocoumarins
Authors: Vedaldi Daniela , Caffieri Sergio , Miolo Giorgia , Dall'Acqua Francesco , Arslan Paola 
Published: August 2018

Abstract
It has been shown that various furocoumarins are able to cause dark hemolysis in red blood cells (RBC). However, this effect is evident only at relatively high furocoumarin concentrations (4.6 x 10-4 M) - much higher than those used in photosensitization experiments or photochemotherapeutic treatments.
Among the various furocoumarins examined in this study, only psoralen (Ps) and 3-carbethoxypsoralen (3-CPs) showed strong photohemolytic effects, while the other compounds revealed little or no activity. This fact indicates that Ps and 3-CPs are able to induce selective damage to the cell membrane of RBC.
By pre-irradiating furocoumarin in ethanol or isotonic saline solutions and adding the irradiated solutions to a RBC suspension, hemolysis was observed in various compounds. The products of photolysis which form during pre-irradiation may be responsible, in terms of hemolysis, for toxic effects on RBC.
Stabilität des Ferricinium-Kations und seine cytostatische Wirkung / Stability of Ferricinium and its Cytostatic Effect
Authors: Wenzel M. , Wu Y. , Liss E. , Neuse E. W. 
Published: August 2018

Abstract
The relative stabilities of different ferricinium cations were studied in buffer or serum-containing solution and in vivo and compared with their cytostatic effects in cultures of Yoshida ascites tumor cells.
Although the ferricinium cation itself was the most unstable cation compared with the dimethyl-ferricinium cation and the deuterated ferricinium derivatives it showed the highest cytostatic effect.
Purification and Characterization of Calcium-Activated Neutral Proteinase from Calf Thymus
Authors: Schwenk Manfred , Zoch Erwin 
Published: August 2018

Abstract
A calcium-activated neutral proteinase (CANP) was prepared from the soluble fraction of calf thymus and purified to electrophoretical homogeneity. The purified proteinase was shown to consist of two subunits, each of 80 kDa, in contrast to rabbit skeletal muscle calpain which was shown to consist of 80 kDa and 30 kDa subunits. The calcium requirement for 50 % activation was 0.55 mᴍ, indicating that this enzyme belongs to the low calcium sensitive type of CANP , named mCANP or Calpain II. Optimal conditions of enzyme activity towards 0.8% casein as substrate are pH 7.5, a calcium concentration of 1.5 mᴍ, the presence of an SH-reducing agent and an incubation temperature of 30 °C. The enzyme is inhibited by Zn2+ , p-chloromercuribenzoate and N-ethylmaleimide.
QSAR of Nitro-diphenylethers as Inhibitors of Cyclic Photophosphorylation
Authors: Oettmeier Walter , Masson Klaus , Donner Andreas 
Published: August 2018

Abstract
A number of 25 nitro-diphenylethers have been synthesized and assayed for their inhibitory activity in N-methylphenazonium-methosulfate mediated cyclic photophosphorylation. Their pI50-values were in the range from 3.5 to 5.3. A QSAR-analysis revealed that the lipophilicity of the nitro-diphenylethers as expressed by ∑π played a major role. In addition, the Taft steric parameter Es in positions 6′, 4′ and 2′ (in decreasing order) contributed to the inhibitory activity. For maximal biological activity, positions 4′ and 6′ should be left unsubstituted whereas a bulky substituent is required for position 2′.
Mass Spectrometry Analysis of Oxygen Gas Exchange in High- and LOW-CO2 Cells of Chlorella vulgaris
Authors: Shiraiwa Y. , Bader K. P. , Schmid G. H. 
Published: August 2018

Abstract
Oxygen gas exchange was monitored in the unicellular green alga Chlorella vulgaris 211 - 11 h by means of a mass spectrometer equipped with a special membrane gas-inlet-system and a photosynthetic reaction vessel. CO2-dependent 18O2-uptake as well as 16O2-evolution were analyzed in both High- and Low-CO2 cells. In High-CO2 cells, the 18O2-ruptake in the light (UL) decreased by 65% upon addition of 3 mᴍ NaHCO3 , while 16O2-evolution (E) was increased approx. 1.8 times by the same treatment. 18O2-uptake in the dark (UD) was not affected by the addition of external inorganic carbon (Ci). The addition of 3.3 mᴍ NaHCO3 also affected UL and E in Low CO2-cells, however, to a minor extent. UL under CO2-saturating conditions was light intensity-independent up to 2 klux and 1.2 klux in High- and Low-CO2 cells, respectively.
Above these light intensities UL increased approx. 4-fold in High- and approx. 6-fold in Low-CO2 cells. Under CO2-limiting conditions, however, UL increased in High-CO2 cells even under very low light intensities, showing that photorespiratory oxygen uptake occurred even in the near vicinity of the light compensation point. Under C02-saturating and strong light conditions UL represented almost half of E in Low-CO2 cells and about 30 % of E in High-CO2 cells. In Low-CO2 cells addition of ethoxyzolamide (EZA), an inhibitor of carbonic anhydrase, enhanced UL and suppressed E and NET under CO2-limiting conditions, whereas the compound had only a minor effect on High-CO2 cells.
DCMU (3 μᴍ) strongly inhibited E and UL under CO2-saturating conditions, with the remaining UL being smaller than UD . KCN (1 mᴍ) and SHAM (1.5 mᴍ) added to DCMU-treated Low-CO2 cells suppressed UL by approx. 50 % . The resulting value corresponded to half of UD . KCN also inhibited E under CO2-saturating conditions, with UL being strongly enhanced showing a maximal uptake at 0.4 mᴍ KCN . Under these conditions NET was nearly zero. The effect seems to be due to an inhibition of RubisCO and an enhancement of Mehler reactions. At 0.7 mᴍ KCN , DCMU entirely inhibited UL , but oxygen uptake appeared increased after turning the light off. This uptake corresponded to approx. 60 % of UD . Whereas KCN and SHAM inhibited approx. 70 % of UD , only 16% of UL was suppressed. These results suggest that the contribution of mitochondrial respiration to UL was negligeable, since UL seemed to be suppressed in the light under CO2-saturated conditions. Iodoacetamide, which is an inhibitor of the Calvin cycle and thereby diverts carbon into the respiratory pathway, inhibited E and NET under CO2-saturating conditions, but did not affect UL . This result also shows that UL is not due to mitochondrial respiration. A hydroxylamine derivative [20, 21] which changes the ratio of the RuBP carboxylation to oxygenation activity in tobacco leaves did not affect this ratio in Chlorella.
Transport of Polyamines in Sugar Beet Seedlings
Authors: Christ Marbeth , Harr Jost , Felix Hansruedi 
Published: August 2018

Abstract
The high levels of polyamines generally found in cotyledons of seedlings might be exported to hypocotyls and radicles. 14C-Labelled putrescine applied to a sugar beet seedling through a cotyledon was found in small amounts as putrescine in the hypocotyl or radicle within a few minutes. Significant amounts of the labelled putrescine, however, were metabolized rapidly to compounds which could not be extracted into the organic phase on dansylation.
The Effect of Bialaphos on Ammonium-Assimilation and Photosynthesis II. Effect on Photosynthesis and Photorespiration
Authors: Ziegler Christine , Wild Aloysius 
Published: August 2018

Abstract
The application of bialaphos (phosphinothricyl-alanyl-alanine) effects a quick photosynthesis inhibition under atmospheric conditions (400 ppm CO2, 21% O2). However, under conditions (1000 ppm CO2, 2% O2) under which photorespiration cannot occur there is no photosynthesis inhibition. In the previous investigation it could be shown that bialaphos splits in plants into phosphinothricin and alanine. The inhibition of glutamine synthetase through freed phosphinothricin results in an NH4
+-accumulation and a decrease in glutamine. With the addition of glutamine, photosynthesis inhibition by bialaphos can be reduced. An NH4
+-accumulation takes place under atmospheric conditions as well as under non-photorespiratory conditions; though in the latter case, in less amounts. After adding glutamine and other amino acids the NH4
+-accumulation increases especially. This indicates that NH4
+-accumulation cannot be the primary cause for photosynthesis inhibition by bialaphos. The investigations indicate that for the effectiveness of either bialaphos or phosphinothricin, a process in connexion with photorespiration plays a considerable role. The glyoxylate transamination in photorespiration could be inhibited, which results probably on a glyoxylate accumulation. Corresponding investigations showed inhibition of photosynthesis as well as a direct inhibition of RubP-carboxylase with glyoxylate.
Kompetitive Hem m ung der Catechol-O-Methyltransferase durch die Tetrahydroisochinolin- Alkaloide Salsolidin und 1-Carboxysalsolin
Authors: Sanft Konstanze , Thomas Helmut 
Published: August 2018

Abstract
The tetrahydroisoquinoline alkaloids salsolidine (1-methyl- 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline) and 1- carboxysalsoline (1-carboxy-1-methyl-6-hydroxy-7-methoxy- 1,2,3,4-tetrahydroisoquinoline), which are themselves not substrates for the enzyme catechol-O-methyltransferase, are - contrary to a hitherto existing view - able to inhibit competitively the methylation of the catecholamine metabolite 3,4-dihydroxybenzoic acid by the enzyme enriched from rat liver. The inhibitor constants were determined to be Ki = 0.19 mM for salsolidine and Ki = 0.44 mM for 1-carboxysalsoline.
Inhibition of Photosystem II by Ioxynil in Wild Type and Resistant Mutant of Synechocystis 6714
Authors: Ajlani G. , Meyer I. , Astier C. , Vernotte C. 
Published: August 2018

Abstract
A Synechocystis 6714 mutant resistant to the phenol-type herbicide ioxynil was isolated and characterized. Ioxynil was shown to inhibit both the donor and the acceptor sides of photosystem II, but at different concentrations. The mutation found in the psbA gene (encoding the D, protein) at codon 266 (asparagine to threonine) [G. Ajlani, I. Meyer, C. Vernotte, and C. Astier, FEBS Lett. 246, 207-210 (1989)] gives a ten-fold resistance of the acceptor side to ioxynil without any modification of the sensitivity of the donor side. Electron transfer between the primary and the secondary acceptor of photosystem II was identical in the mutant and the wild type. The mutant remains sensitive to atrazine and is even more sensitive to DCMU than the wild type.
Species and Genus Specificity of the Intergenic Spacer (IGS) in the Ribosomal RNA Genes of Cucurbitaceae
Authors: Torres R. A. , Zentgraf U. , Hemleben V. 
Published: August 2018

Abstract
The use of intergenic spacer (IGS) fragments of plant ribosomal DNA (rDNA) for the differ­ entiation between genera and species is tested by cross-hybridization experiments with different IGS probes of two Cucurbitaceae, Cucurbita pepo (zucchini) and Cucumis sativus (cucum ber). Hybridization with cloned fragments of different parts of the IGS of ribosomal DNA exhibit a different degree of conservation within and between the Cucurbitaceae genera. In general, Cucur­ bita species seem to be closer related to each other than the Cucumis species. A repetitive element of the external transcribed spacer (ETS) shows a more genus-specific pattern, reacting only with the respective genera; the region preceding the ETS is conserved between the Cucurbita species but also cross-hybridizes weakly with the Cucumis species. AGC-rich element of the Cucumis sativus IGS (“Cfo-cluster”) is present in small amounts in Cucumis melo (melon) and even less represented in other genera of the Cucurbitaceae.
Molecular Orbital Analysis and Quantitative Structure-Activity Relationships for the Anthracycline Antibiotics
Authors: Bushelev S. N. , Stepanov N. F. 
Published: August 2018

Abstract
Semiempirical CNDO/2 calculations of the electronic and molecular structures have been car­ried out for six antitumor anthracycline antibiotics. The strong correlation between their biological activity and such molecular properties as chromophore dipole moment, energy of frontier orbitals, and steric volum es was found and the proper QSAR equations were constructed. The molecular mechanics model showed the weak dependence the DNA-intercalation energy on differences in chromophore constituents (C4 and C9 positions). The expression for the intercala­tion energy has also been obtained on the ground of a quantum-statistical approach: it was applied to the DNA -intercalation energy calculations for the same six anthracyclines. The results agree with the molecular mechanics ones quite satisfactory.
Inhibition of Hill Reaction by 2-Azido-s-triazine Derivatives: QSAR Study with Molecular Connectivity Indices
Authors: Šoškić Milan Š , Sabljić Aleksandar 
Published: August 2018

Abstract
2-A zido-s-T riazines, Connectivity Indices. Inhibition of Hill Reaction. Photosystem II, OSAR Modelling This study was undertaken to find a simple and accurate structural parameters for the quantita­tive description of inhibitory potency of 2-azido-s-triazines in Hill reaction and to gain more information about the mechanism of inhibition on molecular level. A very good correlation (r = 0.946) was obtained between the pl50 values (the negative logarithm of the molar concentra­tion that causes 50% inhibition) and the valence zero-order and the difference between the second-order and the valence second-order molecular connectivity indices. This model, when com pared with the empirical models based on the 1-octano/water partition coefficients and the chromatographic retention data, shows superior performance in accuracy and range of applicabili­ty. In addition, the direct correspondence between molecular structure and above connectivity indices makes it possible to locate structural features responsible for the inhibitory potency of 2-azido-s-triazines in Hill reaction. From our OSAR analysis, the interaction between the chloro­plast receptor site and 2-azido-s-triazines, which causes inhibition of Hill reaction, is primarily influenced by the size of alkylamino substituents and it accounts for the most variation in the pl50 data. The structural features of secondary importance that control the magnitude of pl50’s are the polarity of alkylamino chains and the degree of branching on alpha carbon atom of R:alkylamino substituent. Com pared with the main factor, the size of alkylamino substituents, they can be viewed as a fine tuning elements for the inhibitory potency of 2-azido-s-triazines.