bluuebunny/crossref_metadata_2025_split huggingface dataset:
DEAE-Dextran Induced Increase of Membrane Permeability and Inhibition of Photosynthesis in Dunaliella parva
Authors: Gimmler H. , Lotter G. 
Published: August 2018

Abstract
As a prerequisite for studies of the intracellular distribution of enzym es of the glycerol cycle in Dunaliella parva, the effect of the polycation DEAE-dextran on the permeability of membranes for various endogenous compounds and on photosynthesis was investigated.
DEAE-dextran induces an increase of the permeability of membranes for low and high molecu­lar weight compounds: Under the influence of DEAE-dextran low molecular com pounds of the cells diffuse more rapidly along the chemical concentration gradient into the medium than macro-molecules. Furthermore enzymes of the cytoplasm do occur more rapidly in the outer medium than enzymes of the chloroplasts.
Photosynthetic CO2 fixation is inhibited already at low DEAE-dextran concentrations. This in­ direct inhibition is due to an unspecific efflux of compounds of low molecular weight, such as inorganic cations, metabolites or nucleotides. At high DEAE-dextran concentrations photo­ synthetic electron transport is directly affected at the level of the thylakoids: Electron transport is inhibited between plastoquinone and photosystem I.
The efflux characteristics of marker enzymes of DEAE-dextran treated D. parva cells show that under optimal experimental conditions this technique may be a suitable tool to get information about the intracellular distribution of enzym es of unknown localization in the alga.
New Flavonol Acetates from the Frond Exudate of the Fern Notholaena aschenborniana
Authors: Jay Maurice , Viricel Marie-Rose , Favre-Bonvin Jean , Voirin Bernard , Wollenweber Eckhard 
Published: August 2018

Abstract
The farinose frond exudate of the fern Notholaena aschenborniana was previously shown to contain a mono­ acetate and a mono-butyrate of a 8-hydroxyflavonol as major constituents and the same pair of esters of a second 8-hydroxyflavonol as minor components. Now we have been able to identify the 8-acetates of two further flavonols. The structures of 5-hydroxy-3,7,2′,3′,4′-pentamethoxy-8-acetoxyflavone and 5,4′-dihydroxy-3,7,3′-trimethoxy-8-acetoxyflavone have been elucidated by spectroscopic methods. Both are novel natural products.
Synthesis of 2′-/3′-O-Acylated Adenine Nucleotide Analogs and Their Interactions in Photophosphorylation
Authors: Onur G. , Schäfer G. , Strotmann H. 
Published: August 2018

By mono esterification of 3′(2′)-hydroxyl residues of adenine nucleotides with various carboxylic acids a series of nucleotide analogs is available including fluorescent and photoaffinity labels. Their chemical synthesis is described. The equilibrium between 2′ and 3′ esters is determined by NMR spectroscopy, stability of the esters and their tendency of acyl migration is discussed.
The interaction of the ADP derivatives with the chloroplast ATP synthesizing system is investigated. Actually, the analogs are typical energy transfer inhibitors, strongly inhibiting photophosphorylation and concomitant coupled electron transport (ci50 values ranging from 0.3 to 85 hm). On the basis of inhibitory activities of analogs bearing varying 3′-(2′)-substituents, structure-activity relationships are discussed.
The inhibitory properties of the employed ADP analogs are based on their specific interaction with the catalytic ADP binding site of CF, and their extremely slow phosphorylation on the enzyme (rate 0.25% or less compared to ADP phosphorylation). Inhibition is competitive to ADP but non-competitive with regard to Pi. It is specific for the ADP derivatives, whereas the corresponding ATP analogs are only weak inhibitors in phosphorylation and the AMP derivatives are completely inactive. In light-triggered ATP hydrolysis, however, the ATP analogs exhibit an even stronger competitive inhibition than the ADP derivatives. The results suggest that a conformational change of ATPase takes place when the chloroplasts are transferred from energized to de-energized conditions which greatly affects the properties of the active site with respect to nucleotide binding.
Identification of Anthocyanins and Intermediates of Anthocyanin Biosynthesis from Petunia hybrida Using High Performance Liquid Chromatography
Authors: Schram A. W. , Jonsson L. M. V. , Vlaming P. de 
Published: August 2018

A procedure to identify dihydroflavonol (glucosides), cinnamic acids and anthocyanins in flowers of Petunia hybrida is presented. Nearly all known intermediates and anthocyanins ocur- ring in Petunia are separated on one column using different elution systems. Hydrolysis of extracts before HPLC and thin layer chromatography is in some cases necessary to make positive identification of flavonoids.
Anthocyanins in flowers of Petunia hybrida can occur, depending on genotype, as acylated anthocyanins. Two types of acylated anthocyanins have been identified differing in polarity and thus in retention times on HPLC and TLC. The difference in acylation is genetically deter­mined and gives rise to minor colour differences.
The Influence of the Glycerol-3-Phosphate Level in the Stroma Space on Lipid Synthesis of Intact Chloroplasts
Authors: Sauer Andreas , Heise Klaus-Peter 
Published: August 2018

The G3P level in chloroplasts, rapidly isolated from spinach leaves during a light-dark cycle, oscillated between 2.5 and 4 nmol · mg-1 Chi, which corresponds to a concentration of nearly 0.1 -0.2 mᴍ. In order to study the role of the stromal G3P level on chloroplast lipid biosynthesis, G3P uptake, measured by silicone oil centrifugation, has been correlated with the lipid synthesizing capacity of intact spinach chloroplasts. The level of G3P in the chloroplast stroma was decreased by high orthophosphate (Pi) concentrations in the medium. This decrease was caused by a strong Pi transport into the stroma, which is counterbalanced by a release of phosphorylated metabolites including G3P, mediated by the translocator. But because the reduced stromal G3P concentration exceeded about 3 times that for half saturation of the primary G3P acylation with oleoyl-ACP as preferred fatty acid donor, glycerolipid synthesis was not eliminated. Instead, the lowered G3P level in the stroma space limited the secondary acyla­tion step, indicated by the reduced incorporation of palmitic acid into the diglyceride fraction, and led to an accumulation of free oleic acid. Thus, beside its function as primary acyl acceptor, the stromal G3P level apparently controls the pool size of ACP bound palmitic acid by limitation of the chain elongation step from palmitoyl- to stearoyl-ACP in order to induce the specific palmitic acid channeling into the C-2-position of chloroplast lipids by the secondary G3P acylation.
A similar function may be due to fatty acid consuming reactions from outside the chloroplast like acyl-CoA thioester formation in the outer envelope membrane, stimulated by exogenous CoA and ATP. In contradiction to earlier findings intact Percoll chloroplasts showed a measurable glycerolipid labelling (3-4%) from exogenous [14C]oleoyl-CoA in the presence of G3P (0.5 mᴍ), although most of the radioactivity was found in the free fatty acid fraction (7-10%). Incorporation into diglycerides was increased two-fold under fatty acid synthesizing conditions in the medium and the resulting diglycerides were further galactosylated by UDP- galactose addition. The latter observations suggest, that even in spite of the envelope imperme­ability for physiological concentrations of long-chain acyl-CoA thioesters, fatty acid transfer from these substrates to typical chloroplast lipids cannot be totally excluded.
Rotation of Cells and Ion Exchange Beads in the MHz-Frequency Range
Authors: Küppers G. , Wendt B. , Zimmermann U. 
Published: August 2018

Whereas human red blood cells and protoplasts of leaves of Avena sativa show rotation only at discrete frequencies in the kHz-range of a linear alternating electric field, rota­tion of these cells is observed at practically every fre­quency in the MHz range (15 to 200 MHz).
The cell rotation in the MHz-range can be explained in terms of field induced polarisation and orientation of per­manent dipoles within the membrane and the cell.
This interpretation is supported by the finding that Chelex beads (polystyrene cross-linked with divinylben- zene and coupled to iminodiacetic acid) do exhibit rota­tion in the MHz-range, but not in the kHz-range. It is most interesting that the Cu2+- and Ca2+-forms of the Chelex beads show a shift in the rotation frequency spectrum in addition to an increase in the magnitude of the rotation speed with respect to the Na+-form. At frequencies in the MHz-range at which rotation of the Chelex beads is not observed, formation of chains of beads from the electrodes occurs instead. This is due to positive polarisation of the beads leading to positive dielectrophoresis. The results support the view that rotation needs negative polarisability which is determined by the functional groups.
Activation and Inhibition of Na/K-ATPase by Filipin-Cholesterol Complexation. A Correlative Biochemical and Ultrastructural Study on the Microsomal and Purified Enzyme of the Avian Salt Gland
Authors: Gassner Dieter , Komnick Hans 
Published: August 2018

Abstract
The Na/K-ATPase-rich microsomal fraction and purified Na/K-ATPase membranes of the salt-stressed avian salt gland were studied at defined filipin/cholesterol molar ratios (F/C) using enzyme assay and electron microscopy including negative staining, thin sectioning and freeze frac­ turing. Comparative examinations of detergent-treated microsomal fractions and the use of elec­ tron microscopic tracers revealed that F/C up to 2 activated latent Na/K-ATPase in sealed right-side-out vesicles by increasing membrane permeability without disrupting the vesicular mem­ brane. Therefore, filipin offers an alternative to the detergents for the activation of latent vectorial membrane enzymes and a possible tool to examine their subcellular localization and sidedness in the membrane. The same F/C had no stimulatory effect on the microsomal anion-ATPase sug­gesting that the 2 ATPases are not located in the same membrane.
Increasing F/C applied to the unfixed Na/K-ATPase membranes caused an increase in the number of structural F-C-complexes and a progressive lateral displacement of the enzyme par­ ticles which finally led to a separation of the areal distribution of these structures at F/C = 10. Such displacements did not occur in unfixed microsomes and were prevented by glutaraldehyde fixation of the purified membranes.
F/C exceeding 2 progessively and temperature-dependently inhibited the Na/K-ATPase in its membrane-bound states, whereas the solubilized enzyme was rather insensitive. The structural and biochemical data suggest that inhibition results from the perturbation of the lipidic microen­ vironment of the enzyme caused by filipin-cholesterol complexation.
Incorporation of a Voltage Sensitive Pore from Guinea Pig Heart Mitochondria into Black Lipid Membranes and Characterization of Electrical Properties
Authors: Schreibmayer W. , Hagauer H. , Tritthart H. A. 
Published: August 2018

Abstract
A pore from guinea pig heart mitochondria has been incorporated into BLM's (Black lipid membranes) in a highly oriented manner and its electrical properties studied. The pore shows multistate behaviour, the distribution of the pore between different conducting states being very sensitive to voltage. This has been proven by computation of single-pore experiments. Highest single pore conductance was 4.5 nSi in 1 ᴍ KCl, independent of voltage and with no detectable preference for cations or anions. The pore from guinea pig heart mitochondria reacts more sensitivly to voltage than pores of mitochondria from other tissues so far incorporated into BLM's.
Conical Kinetochores with Single Microtubules in the Micronuclear Mitosis of the Ciliate Colpoda steinii
Authors: Kuck A. , Ruthmann A. 
Published: August 2018

Abstract
During micronuclear metaphase, the decondensed chromosomes bear conical kinetochores connected by a single microtubule to the tapered ends of the spindle-shaped nucleus. Using Bernhard's procedure for the pre­ ferential staining of ribonucleo-protein-containing struc­ tures, the whole kinetochore cone retains its electron density. Chromosome separation at anaphase involves shortening of the kinetochore microtubule and elongation of the interpolar region.
Antifungal Phytoalexins in Phaseolus aureus Roxb
Authors: O’Neill Melanie J. , Adesanya Saburi A. , Roberts Margaret F. 
Published: August 2018

Abstract
Eight phytoalexins have been isolated from Phaseolus aureus (mung bean) seedlings after treatment with aqueous CuCl2. These compounds include three isoflavones: genistein, 2′-hydroxygenistein and a compound tentatively identified as 2,3-dehydrokievitone, four isoflavanones: dalbergioidin, kievitone, cyclokievitone and 5-deoxykievitone, and the pterocarpan phaseollidin. The antifungal activities against Cladosporium cucumerinum were determined.
Aureol and Phaseol, Two New Coumestans from Phaseolus aureus Roxb
Authors: O'Neill Melanie J. 
Published: August 2018

Abstract
Two new coumestans, aureol and phaseol, isolated from Phaseolus aureus have been charac­terized as 1,3.9-trihydroxycoumestan and 3,9-dihydroxy-4-(γ,γ-dim ethylallyl)-coumestan, respectively.
Composition of the Heterogeneous Sex Attracting Secretion of the Dung Beetle, Kheper lamarcki
Authors: Burger B. V. , Munro Zenda , Röth Marina , Spies H. S. C. , Truter Verona , Tribe G. D. , Crewe R. M. 
Published: August 2018

The white flocculent sex attracting secretion produced by the male dung beetle, Kheper
lamarcki MacLeay, was found to consist of tubular polypeptide fibres containing hexadecanoic acid, 2,6-dimethyl-5-heptenoic acid and (E)-nerolidol as major components, while a trace of skatole is responsible for the unpleasant odour of the secretion.
Notizen: ESR Investigations on the M odification o f the Ascorbic Acid-Erythrocyte Interaction by Ferrous Ions
Authors: Lohmann W. , Kiefer B. , Holz D. , Schmidt D. , Schreiber J. 
Published: August 2018

Abstract
An ascorbic acid-erythrocyte interaction results in the formation of the semidehydroascorbate (SDA) radical and an increase in spin concentration. Addition of a more than ten-fold concentration of Fe2+ (as FeSO4) to such a system compensates the effect produced by ascorbic acid, that is the electron spin resonance spectrum obtained resembles very closely that of erythrocytes only. With the dis­appearance of the SDA radical a high spin ferric ion signal appears concomitantly at g = 4.3.
Studies on the Functional Mechanism of System II Herbicides in Isolated Chloroplasts
Authors: Renger G. , Hagemann R. , Vermaas W.F.J. 
Published: August 2018

The effect of specific proteolytic enzymes on variable fluorescence, p-benzoquinone-mediated oxygen evolution, PS II herbicide (atrazine and bromoxynil) binding, and protein degradation has been analyzed in isolated class II pea chloroplasts.
It was found that:
1. Trypsin and a lysine-specific protease effectively reduce the maximum chlorophyll-a fluorescence yield, whereas the initial fluorescence remains almost constant. At the same number of enzymatic activity units both proteases have practically the same effect.
2. Trypsin and a lysine-specific protease inhibit the p-benzoquinone-mediated flash-induced oxygen evolution with trypsin being markedly more effective at the same number of activity units of both enzymes. Unstacked thylakoids exhibit a higher sensitivity to proteolytic degradation by both enzymes.
3. Trypsin and a lysine-specific protease reduce the binding capacity of [14C]atrazine, but enhance that of [14C]bromoxynil (at long incubation times trypsin treatment also impairs bromoxynil binding). At the same specific activity a markedly longer treatment is required for the lysine-specific protease in order to achieve the same degree of modification as with trypsin.
4. Trypsin was found to attack the rapidly-turned-over 32 kDa-protein severely, whereas the lysine-specific protease does not modify this polypeptide. On the other hand, the lysine-specific protease attacks the light harvesting complex II.
5. Under our experimental conditions an arginine-specific protease did not affect chlorophyll-a fluorescence yield, p-benzoquinone-mediated oxygen evolution, herbicide binding and the poly- peptide pattern.
Based on these results a mechanism is proposed in which an as yet unidentified polypeptide with exposable lysine residues, as well as the lysine-free “QB-protein” regulate the electron transfer from Q-
A to QB and are involved in herbicide binding.
Metribuzin-Resistant Mutants of Chlamydomonas reinhardii
Authors: Pucheu N. , Oettmeier W. , Heisterkamp U. , Masson K. , Wildner G.F. 
Published: August 2018

Herbicide resistance in Chlamydomonas reinhardii cells was induced by mutagenesis with 5-fluorodeoxyuridine and ethylmethanesulfonate. Four mutant strains were isolated and analyzed for resistance against DCMU-type or phenolic inhibitors of photosynthetic electron transport.
The mutants were different in both the extent and the pattern of their resistance: the R/S value, i.e. the ratio of I50 values of the inhibition of photosynthetic electron transport in isolated resistant and susceptible thylakoids, varied for metribuzin from 10 000 to 36. The mutant MZ-1 was resistant against metribuzin, atrazine and DCMU, whereas the mutant MZ-2 showed resistance mainly against metribuzin and atrazine. The mutant MZ-3 was similar to MZ-1, but showed a lesser extent of resistance against DCMU. The mutant MZ-4 showed resistance against metribuzin, but not against atrazine. These results demonstrate that the resistance against one herbicide of the DCMU-type (metribuzin) must not be accompanied by similar resistance against te other inhibitors. Binding studies with radioactively labeled herbicides, [14C]metribuzin, [14C]atrazine and [3H]DCMU, and isolated thylakoids supported these observations.
Phosphorylation of thylakoid membrane proteins was studied with wild-type cells and resistant mutants under in vivo conditions in the light. The 32P-labeled main proteins bands were in the molecular weight range of 10-14 kDa, 26-29 kDa, 32-35 kDa and 46-48 kDa. The pattern and the extent of incorporation of 32P were similar for the mutants and the wild-type cells.
Purification of Soybean DNA-Dependent RNA Polymerase I on a Column of Plasmid pHFK 206 Covalently Attached to Agarose
Authors: Grossmann Klaus , Friedrich Harald , Seitz Hanns Ulrich 
Published: August 2018

The plasmid pHFK 206 consisted of plasmid pBR 322 and an 1.3 × 10-6 D insert, a cloned seg­ment of a soybean rRNA repeating unit with a preferential binding region for soybean RNA polymerase I, was coupled to cyanogen bromide activated agarose (Sepharose 4B) and used for affinity chromatography of RNA polymerases.
It could be shown by elution profiles and sodium dodecylsulphate/polyacrylamide slab gels that highly purified RNA polymerase from Escherichia coli MRE 600 bound to pHFK 206- Sepharose as holoenzyme with an apparently full complement of σ-subunit. With initially purified soybean RNA polymerase I from chromatin of 2,4-D treated hypocotyls it was demonstrated that pHFK 206-Sepharose could be used as an affinity chromatography method for purification of soybean RNA polymerase I in high degrees and economy of time.
Causal Relationships among Metabolic Circadian Rhythms in Lemna
Authors: Goto Ken 
Published: August 2018

Abstract
Biochemical aspects of circadian rhythms were studied using a long-day duckweed, Lemna gibba G3 cultured in short day condition (9 h light at 3800 lux followed by 15 h darkness), which was transferred in continuous light (LL) at the end (LL 0) of the last night period. With such a system I have previously reported a rhythm of affinity for NAD+ of cytoplasmic NAD - dependent glyceraldehyde 3-phosphate dehydrogenase (Cyt-NAD -GPD ) 180° out of phase with that of affinity for NADP+ of chloroplastic NADP-dependent GPD (Chl-NADP-GPD ) and that NADP+ could increase in vitro the affinity for NADP+ of Chl-NADP-GPD . I report here that NADP+ can decrease in vitro the affinity for NAD+ of Cyt-NAD -GPD as well, and furthermore, that the in vivo level of NADP+ oscillates in phase with the rhythm of the affinity for NADP+ of Chl-NADP-GPD.
Moreover, I found the existence of mirror-image circadian rhythms, of comparable am plitudes, of in vivo levels of NAD+ + NADH (total NAD) (with peaks, as the ones of Cyt-NAD - GPD. at LL 0 and 24) and of NADP+ + NADPH (total NADP) (with peaks, as the ones of Chl-NADP-GPD, at LL 12 and 36). Consequently, a circadian rhythm in the rate of net in vivo production of total NADP (or NAD) might be expected 90° in advance of that in the level of total NADP (or NAD). Indeed. I found oscillations in the activities of NAD kinase and of NADP phosphatase with peaks occurring, respectively, at LL 6 and at LL 18. Moreover, in vitro treatments with EGTA (a Ca2+-chelator), chlorpromazine and W7 (both inhibitors of calmodulin) were able to both inhibit NAD kinase from its highest level of activity to its minimal one and activate NADP phosphatase from its lowest level of activity to its maximal one. I conclude, therefore, that the in vivo level of Ca2+-calmodulin could oscillate in phase with the rhythm of NAD kinase activity and induce the mirror-image circadian rhythms of activities of NAD kinase and of NADP phosphatase.
I propose that the control sequence among the several circadian rhythms I studied could start with changes in Ca2+-calmodulin, then proceed through oscillations in NAD kinase and NADP phosphatase activities, leading to changes in NAD+, NADP+, and NADPH levels, which would themselves induce the Chl-NADP-GPD and Cyt-NAD -GPD rhythms.
Product Specificity during Incubation of Methyl Linoleate with Soybean Lipoxygenase-I
Authors: Hatanaka Akikazu , Kajiwara Tadahiko , Sekiya Jiro , Asano Masashi 
Published: August 2018

Abtract
The ratios of 13:9 isomers of the hydroperoxides produced during incubation of methyl linoleate with soybean lipoxygenase-1 were ca. 50:50 at pH 7.8 and ca. 70:30 at pHs 9.0 and 11.0, respectively. In striking contrast to the lipoxygenase-catalyzed hydroperoxidation of linoleic acid, the hydroperoxidation of methyl linoleate at pH 7.8 gave almost racemic 13-hydroperoxides and that at pHs 9.0 and 11.0 yielded methyl 13-L-hydroperoxylinoleate having low optical purities (L/D, ca. 45/30).
Dopamine Accumulation in Papaver somniferum Latex
Authors: Homeyer B. C. , Roberts Margaret F. 
Published: August 2018

Abstract
Organelles found in the 1000 x g fraction of latex taken from Papaver somniferum have been shown to accumulate dopamine to the exclusion of other catecholamines. Dopamine accumula­ tion is both temperature and pH dependent and there is no evident requirement for ATP (1 mᴍ) or Mg2+ (2mᴍ). The relatively high (4.37 mᴍ), specificity of dopamine uptake, and insensitivity to inhibitors distinguish papaver latex organelle dopamine uptake from catecholamine uptake by mammalian chromaffin granules.
Differential Synthesis of Alkaline Phosphatase in Rhizobium Species Isolated from the Tropics
Authors: Singh Akhand P. , Singh J. B. 
Published: August 2018

Abstract
A total of 28 strains of several species of Rhizobium were screened for the presence and regulation of the enzyme alkaline phosphatase. In contrast to all other species of Rhizobium, the activity of this enzyme was absent in R. trifolii. Different levels of alkaline phosphatase were observed in various species of Rhizobium. Both, species as well as strain specific differences were found in the level of alkaline phosphatase.
Fluorescence-ODMR of Reaction Centers of Rhodopseudomonas viridis
Authors: Angerhofer A. , Schütz J. U. von , Wolf H. C. 
Published: August 2018

Abstract
Fluorescence detected ODMR measurements in zero field on the triplet state of the reaction center in whole cells of Rhodopseudomonas viridis, in reaction center solution and in reaction center crystals are reported. In solution and in the crystal a sign reversal of the F-ODMR signals is observed by variation of the wavelength of detection. The signs of the signals are interpreted with the Vredenberg-Duysens relation.