bluuebunny/crossref_metadata_2025 huggingface dataset:
Quasielastische Lichtstreuung von isoliertem Chromatin / Quasielastic Light Scattering of Isolated Chromatin
Authors: Meuel Bernd , Notbohm Holger
Published: August 2018

Chromatin undergoes structural changes in dependence on the ionic strength of monovalent cations. At low ionic strength an extended chain of nucleosomes is apparent while with increasing ionic strength more compact structures are formed. Soluble chromatin was prepared from rat liver and fractionated by gel chromatography. Quasielastic light scattering experiments on chromatin were done with monovalent salt concentrations ranging from 3-150 mм.

Using this method translational diffusion coefficients have been derived. These appeared to be nearly independent of monovalent salt concentrations, indicating that the hydrodynamic radius of chromatin molecules did not change. On the other hand, sedimentation coefficients were increasing according to an exponential relation. Taken together, both findings reveal a rising of the molar mass with increasing ionic strength. On the contrary, chromatin prepared in physiological salt apparently disintegrates by lowering the ionic strength. Furthermore, it could be demonstrated by earlier small angle X-ray scattering studies that the diameter of the higher order chromatin fiber remained constant at approximately 32 nm even if these structures had been reconstituted from smaller pieces starting at low ionic strength. Thus, isolated chromatin fibers are capable of self-assembling to regular quaternary structures, even if the DNA does not form a continuous strand.
On the Construction of “Optimal” Phylogenetic Trees
Authors: De Soete Geert
Published: August 2018

An iterative algorithm for constructing the optimal phylogenetic tree from a given set o f dissimilarity data is described. The procedure is applied for illustrative purposes an a data set com piled by Fitch and Margoliash.
Wounding-Induced Increase of Quinolizidine Alkaloid Accumulation in Lupin Leaves
Authors: Wink M.
Published: August 2018

Cutting-up leaflets of Lupinus polyphyllus induces a rapid increase of quinolizidine alkaloid accumulation of up to 400% within 2 to 4.5 h. In contrast to the diurnal alkaloid formation, this reaction takes place both in the light and the dark and even at 4°C. The effect is reduced in chloramphenicol-treated samples but unimpaired in cycloheximide-treated assays. Since quinolizidine alkaloids constitute probably an important means of a chemical defense system of lupins against microbes and herbivores, the wound-induction of alkaloid accumulation is discussed as a defense responsf
Der einfluß von cycloheximid und chloramphenicol auf die biosynthese der photosynthese-pigmente in cyanophora paradoxa korsch. I. Photosynthetische Sauerstoffproduktion / The influence of cycloheximide and chloram phenicol on the biosynthesis of the photosynthetic pigments in cyanophora paradoxa. I. Photosynthetic Oxygen Evolution
Authors: Schenk Hainfried E. A. , Neu-Müller Margarete
Published: August 2018

It is not clear whether an endocytobiont is able to develop during a long evolution tim e only to an organelle like cell structure (defect mutant) with a high degree of m etabolic dependency or also to a perfect cell organelle with genetical dependency to the host nucleus (intercom partm ental translocation of proteins and/or gene transfer) in the sense of the Serial Endocytobiosis Hypothesis (SEH). Cyanocyta korschokoffiana, the endocyanelle of C. paradoxa, seems to be a very suitable object to answer this question. Therefore we have studied the influence of the translation inhibitors cycloheximide (CHI) and chloramphenicol (CA) on the biosynthetic behaviour of this cyanobacterial endocytobiont regarding the photosynthetic oxygen during 20 h developing and incubation time. After dilution with fresh culture medium the oxygen evolution of the control culture remains nearly constant, if it is related to the phycocyanin content, whereas it increases slowly to a constant level relating to the chlorophyll content (nearly 140-150% of the starting activity). CHI and CA show a rapid effect on the oxygen evolution. At the first 8 - 10 h the oxygen evolution of cultures treated with CA are hardly dim inished and remain more or less constant with regard to the starting activity, but that of cultures treated with CHI decreases strongly. After 24 h the CHI treated flagellate is photosynthetically inactive and far-reaching destroyed (microscopic observations), indicating that CHI has beside the inhibition effects on protein synthesis also secondary effects on the stability of membranes of C. paradoxa
Sex Pheromone Components of the Gamma Moth, Autographa gamma (L.) (Lepidoptera: Noctuidae)
Authors: Dunkelblum E. , Gothilf S.
Published: August 2018

Z-7-Dodecenyl acetate and Z-7-dodecenyl alcohol have been identified as sex pheromone components o f female Autographa gamma. This is the first time that Z-7-dodecenyl alcohol has been found in the natural pheromone of Plusiinae. When incorporated in pherom one traps of some Plusiinae species the alcohol is both synergist and inhibitor, thus being an important factor in sex isolation among sympatric Plusiinae species in Israel
N-Terminale Sequenz einer Porphobilinogen-Synthase * N-Terminal Sequence of a Porphobilinogen-Synthase
Authors: Lingner Birgit , Kleinschmidt Traute
Published: August 2018

The N-terminal sequence of porphobilinogen-synthase (EC 4.2.1.24) from bovine liver up to position 44 is given. After tryptic hydrolysis two N-terminal peptides with identical amino acid composition were isolated in the ratio 1:1. One peptide was blocked whereas the other one started with methionine and showed the same primary structure which had been estimated by automatical degradation of the enzyme. Four of the eight subunits of PBG-S have free methionine as N-terminal amino acid whereas the other half is blocked
Isolation and Structure Determination of the Precursors of a-and y-Irone and Homologous Compounds from Iris pallida and Iris florentina
Authors: Krick W. , Marner F.-J. , Jaenicke L.
Published: August 2018

Rhizomes of Iris pallida and Iris florentina contain - increasing on storage - violet-like smelling C14-ketones (irones 1 a-c) which develop by oxidative degradation of C31-triterpenoids. The structure of these precursors is reported as well as the structure of respective C30-homologues.

The unusual C31-structures may derive biogenetically from the respective C30 compounds by a methylation which initiates the formation of the ring-closed irone-moiety
Isolierung und Identifizierung von Sterinen im Metabolismus des Pilzes Botrytis cinerea / Isolation and identification of sterols in the metabolism of the fungus botrytis cinerea
Authors: Flesch Peter , Gwinner Lutz , Müller Sylvia , Simon Peter
Published: August 2018

The fungus Botrytis cinerea, which belongs to the class of ascomycetes, has been analysed for its sterol composition. It is able to produce ergosterol, cerevisterol, lanosterol/dihydrolanosterol and cholesterol besides β-sitosterol. The identification of the sterols is carried out with different analytical methods including mass spectrometry. In the extracts of the mycelium also squalene has been identified
Sulfide Stimulation of Light-Induced Hydrogen Evolution by the Cyanobacterium Nostoc muscorum
Authors: Weißhaar H. , Böger P.
Published: August 2018

Light-induced hydrogen evolution by the blue-green alga Nostoc muscorum is stimulated by sulfide with a rate of about 20 (μmol H2 per mg chlorophyll and hour stable for about one day at low light intensities (7 W/m2). Oxygen evolution does not impair sulfide-stimulated hydrogen formation. Increased hydrogen evolution is catalyzed by nitrogenase, its activity is not influenced by sulfide. Apparently, sulfide inhibits the hydrogen-uptake pathway(s), thereby increasing net hydrogen evolution. - Furthermore, photosynthetic electron flow is inhibited by sulfide, essentially at the oxidizing side of photosystem II, as was dem onstrated by fluorescence-signal changes. This leads to decreased electron supply of nitrogenase.

Hydrogen production apparently is at optim um when both the effect o f sulfide on photosynthesis is moderate and when uptake-hydrogenase activity is abolished
Circular Permutation Analysis of Phage T4 DNA by Electron Microscopy
Authors: Grossi G. F. , Macchiato M. F. , Gialanella G.
Published: August 2018

Phage T4 is known to have a linear duplex chromosome that is circularly perm uted and terminally repeated. We found, by denaturation and self-reannealing experiments, that circular permutation in T4 native DNA is not random. Their multimodal distribution of permutation is compatible with the “headful packaging” model with the additional specifications that the encapsulation of DNA starts at several sites and these are not random distributed
Regulation of Nitrogenase Activity in Rhodopseudomonas capsulata AD 2
Authors: Alef Kassem
Published: August 2018

Regulation of nitrogenase activity in Rhodopseudomonas capsulata AD 2 differs in several respects from other Rhodospirillaceae:

1)Nitrogenase activity in this strain grown under severe N-starvation was fully derepressed, but in contrast to other Rhodospirillaceae, it was inhibited by ammonia in vivo.

2)Nitrogenase in extracts of glutamate grown cells was fully active and not further stimulated by Mn2+.

3)Treatment of N-starved or glutamate grown cells with ammonia before harvest did not cause inactivation of nitrogenase in vitro.
Effect of Pressure on the Absorption Spectra of Phycobiliprotein and Porphyridium cruentum
Authors: Brody Seymour Steven , Stelzig Lisbeth
Published: August 2018

Changes in the absorption spectra of P. cruentum and phycobiliprotein are observed as a function of hydrostatic pressure. With phycobiliprotein both in solution and in algae, increasing hydrostatic pressure results in bathochromic shifts of the absorption maxima. In addition, there is a splitting of the absorption band of phycoerythrin.

When P. cruentum is subjected to 250 bars there are increases in absorption by chlorophyll (at 700 and 698 nm), phycocyanin (at 640 nm) and phycoerythrin (at 580 and 550 nm). When a cell free solution of phycobiliprotein is subjected to 300 bars there are increases in absorption by phycoerythrin (at 570 and 550 nm) and phycocyanin (at 634 nm).
The Influence of the Extracellular Concentration of Calcium, Magnesium and Sodium on the Repolarizing Phase of the Receptor Potential of the Limulus Ventral Nerve Photoreceptor
Authors: Stieve H. , Gaube H.
Published: August 2018

1.Lowering the extracellular calcium concentration from 10 mmol/l to 1 nmol/l causes, besides reducing membrane potential (PMP) and peak amplitude (hmax) of the light response of the Limulus ventral nerve photoreceptor (see Stieve and Bruns [1]), a prolongation of the time course of the light response.

The retarded time course (characterized by latent-period tlat, time-to-peak tmax, decrease time t2 and decline quotient QHN) caused by low calcium concentration is not antagonized by either reducing the sodium concentration (from 0.5 to 0.05 mol/l) or increasing the magnesium concentration (from 5× 10-5 to 5 × 10-2 mol/l) in contrast to the effects on the PMP and hmax. 2.

This effect of lowering the calcium concentration on the time course of the ReP is distinctly different from that on membrane potential and transient of the ReP described before.

It is not characterized by a calcium/sodium binding competition but is probably more closely related to the bump-generating mechanism. It can be explained on the assumption that the time parameters of the ReP are primarily determined by the latency distribution of the underlying bumps which is expanded under low calcium conditions.
Differential Regulation of Flavone Glycosylation during Ontogeny of Silene pratensis
Authors: Steyns J. M. , Nigtevecht G. van , Niemann G. J. , Brederode J. v.
Published: August 2018

Two isovitexin glycosides have been found in the cotyledons and foliage leaves of Sitene pratensis plants that are unable to glycosylate isovitexin in their petals (genotype gg glgl fgfg). The glycosides (isovitexin 7-O-galactoside and isovitexin 7-O-galactose 2″-O-arabinoside) were present only in the lower leaves: leaves produced later in the development of the flower stem accumulated only the aglycon isovitexin. The transition in the flavone composition during the ontogeny of the plants could be influenced by light intensity. In plants grown at low light intensity, glycoside production continued until a higher leaf pair number than in plants grown at higher light intensities. However, the effect of light intensity is indirect: the transition in the flavone composition is correlated with the transition from rosette leaves to stem leaves. The presence of the 7-O-galactosides in cotyledons and rosette leaves suggests that in addition to the g, gl and fg loci, there are further glycosylating loci which are not expressed in stem leaves and petals.
Untersuchungen zur Synthese und biologischen Bedeutung von Glutaminsäure-1-semialdehyd als Vorstufe der Chlorophylle / Investigations on the Synthesis and Biological Significance of Glutamic-1-semialdehyde as a Precursor of the Chlorophylls
Authors: Meisch Hans-Ulrich , Maus Raimund
Published: August 2018

Glutamic-1-semialdehyde which is discussed to be involved in the early steps of chlorophyll biosynthesis, has been synthesized from glutamic acid by reduction of several N-protected carboxylic acid derivatives like the N-CBO-glutamic acid-1-dimethyl amide or methylanilide, the pyroglutamic acid imidazolide and the acid chlorides of N-phthaioyl-glutamic acid-5-methyl ester or 5-benzylester. The α-aminoaldehyde could only be generated in solution, where it is polymerized rapidly. Due to its instability, it is suggested thal glutamic semialdehyde plays no role as a free metabolite in green plants.
Effect of 5′-Terminated (2′— 5′)-01igoadenylates on Cap Degrading Activities in Rat Liver Nuclei
Authors: Michels Winfried , Schlimme Eckhard
Published: August 2018

(2'-5')-oligoadenylates bearing a 5'-terminal triphosphate or a 5'GTP-group inhibit the activity of a dinucleoside triphosphatase in rat liver nuclei thereby protecting mRNA against 5'-exonucleolytic degradation. (2'-5')-oligoadenylates, on the other hand, were known to enhance the activity of an endoribonuclease, RNaseF. Thus a synergistic effect may be assumed in vivo, i.e. cellular metabolism seems to be protected twice in virus-infected cells.
Effects of Pyridazinone Herbicides during Chloroplast Development in Detached Barley Leaves I. Effects on Pigment Accumulation and Fluorescence Properties
Authors: Laskay G. , Lehoczki E. , Maróti I.
Published: August 2018

The effects of three differently substituted pyridazinone herbicides on the accumulation of photosynthetic pigments and on the fluorescence properties of greening barley leaves were studied. The two trifluoro-methyl derivatives, SAN 6706 and 9789 caused inhibition in the accumulation of carotenes only after the first 24 h of greening. By the 48th hour of greening no detectable amounts of carotenes were present in the treated leaves. Considerable amounts of xanthophylls however remained present, and no bleaching of the leaves was observed. It is suggested that SAN 6706 and 9789 prevent the formation of the enzyme(s) catalyzing the desaturation of phytoene and phytofluene. Fluorescence spectra indicate that the organization of pigment forms altered seriously in the treated leaves. This experimental system may be useful to study the action of pyridazinone herbicides without causing complete photobleaching of the photosynthetic apparatus. SAN 9785 had only minor effects on pigment accumulation and also on the organization of pigment forms. The possible explanations of the effects observed are dis­cussed.
The Effects of Tumor Sera on Cell Shape and Photosynthesis of Euglena gracilis
Authors: Ruppel H. G. , Benninghoff B.
Published: August 2018

Cells of Euglena gracilis treated with human sera show a marked change in cell shape: Fully elongated cells have nearly totally been transformed to disk-shaped cells. This serum-mediated contraction is followed by irreversible cytolysis. Disintegration of chloroplast membranes leads to decreased photosynthetic O2 evolution. Sera from humans suffering from tumors reveal higher lytic activities than sera from individuals not suffering from tumors. Heating sera at 56 °C for 10 min or addition of EDTA destroyed or inhibited, respectively, the lytic activities completely. Polysaccharides transformed in polyanions by sulphatisation like dextransulphates or heparin seem to protect Euglena against serum activities.

The effects described for human sera are believed to display the role of the complement pathway in the cytolysis of Euglena gracilis.
Lipids and Enzymatic Activities in Vacuolar Membranes Isolated via Protoplasts from Oat Primary Leaves
Authors: Verhoek Britta , Haas Renate , Wrage Käthe , Linscheid Michael , Heinz Ernst
Published: August 2018

Vacuoles were released from oat (Avena sativa) mesophyll protoplasts and purified by sedi­mentation and flotation. Disruption of isolated vacuoles followed by density gradient centri­fugation gave two membrane bands which after combination were further purified on sucrose gradients. A significant contamination by microbodies, thylakoids, mitochondria, endoplasmic reticulum and Golgi membranes can be excluded, whereas markers for plasma membrane and chloroplast envelope were present in the final membrane preparation.

In the purified membrane fraction the following enzymatic activities were detected: NADH- cytochrome C reductase E.C. 1.6.2.2, ATPase E.C. 3.6.1.3. UDPG: sterol glucosyltransferase, UDP-Gal: diacylglycerol galactosyltransferase E.C. 2.4.1.46, glucan synthetase II, CDP-choline: diacylglycerol phosphocholinetransferase E.C. 2.7.8.2, formation of acylgalactosyl diacylglycerol and acyl-CoA thioesterase E.C. 3.1.2.2. None of these can be considered to be specific for the tonoplast. Acid phosphatase E.C. 3.1.3.2 was present in the cell sap.

The vacuolar membranes contain phospholipids and glycolipids of the most complex composi­tion found so far in a membrane system isolated from mesophyll protoplasts. About half of the glycolipids were accounted for by glycosyl diacylglycerols usually considered to be confined to plastids. Steryl glycosides and acyl steryl glycosides were other prominent glycolipids. A cerebroside was the predominating lipid component of this membrane preparation.
A Study on Oxygen Evolution and on the S-State Distribution in Thylakoid Preparations of the Filamentous Blue-Green Alga Oscillatoria chalybea
Authors: Bader Klaus P. , Thibault Pierre , Schmid Georg H.
Published: August 2018

When thylakoid preparations of the filamentous blue-green alga Oscillatoria chalybea are exposed to short (2 or 8 μs) saturating light flashes, the oxygen evolution pattern can be distinguished in several respects from the one usually observed in Chlorella. Thus, it appears that a substantial electrochemical signal is already seen under the first flash with maximal flash yield always occurring under the fourth flash. This refers to dark adapted preparations (up to 60 min). Fitting of such an experimental sequence in the 4-state Kok model yields an S-state population consisting of 36-41% S0, 40-49% S1, 1-10% S2 and up to 13% S3. No abnormality under the first flash is seen in such preparations. Characteristic for sequences with Oscillatoria prepara­tions is a high level of misses which are in the region of 25 per cent, whereas double hits do not seem to play a substantial role in the damping of such sequences. The existence of metastable S3, anyway inconsistent with the coherent Kok model, is not confirmed by mass spectrometry. No 18O2 seems to be evolved under the first flash from Oscillatoria thylakoids suspended in 50% H2
18O. although, when judged from the absolute amperometric signal amplitude, mass spectrometric detection of O2 should have been possible. With the same method we are fully able to detect 18O2 under the second flash in Chlorella vulgaris. In Chlorella this is true for experimental conditions in which the amperometric signal amplitude under the second flash is even smaller than those under the first or second flash in Oscillatoria. The attempt to correlate the amperometrie signal observed under the first flash with a photoinhibition of respiration in our pro­karyotic organism was not successful. However, the attempt to incorporate the phenomenon in the coherent Kok model shows that the Oscillatoria sequence fully resembles those with Chlorella, if the first flash signal and 40-50% of the signal observed under the second flash is simply removed from the sequence. The remaining sequence exhibits the usual properties known from Chlorella or higher plant chloroplasts. If one assumes contribution of the reduced state S-1 to the dark population of S-states, a fit in the five rank Kok model yields correct adjustments with a S-state distribution of 6-20% S-1, 31-40% S0, 49-54% S1, 0% S2 and 0% S3 which would be fully consistent with the Kok model and corresponds to the distribution observed with Chlorella or higher plant chloroplasts. The question what the first electrochemical signal is due to remains unanswered.
Immobilization of E. coli Cell as an Antigen by Radiation Polymerization Method
Authors: Kaetsu lsao , Kumakura Minoru , Kikuchi Shintaro , Adachi Shoichi , Suzuki Mieko
Published: August 2018

E. coli NIJ cells were immobilized by radiation polymerization of 2-hydroxyethyl methacrylate at low temperatures. The immobilized E. coli cells as an antigen were reacted with peroxidase labeled anti-E. coli in competition with the free E. coli cells. It was found that E. coli cells can be assayed quantitatively with the immobilized E. coli cells in disc form. Microorganisms such as gram negative bacteria had no specific affinity to anti-E. coli. Cross reactivity of the immobilized E. coli cells with the E. coli cells from various strains was examined.
Hydratwasseraustausch und Alkanol-induzierte Molekulare Umordnungen an Kollagen/Exchange of the Structural Water of Collagen and Alcanol-Induced Molecular Rearrangement
Authors: Nemetschek Th. , Knörzer E. , Folkhard W. , Geerken W. , Jelinek K. , Kuhlemann C. , Mosler E. , Nemetschek-Gansler H.
Published: August 2018

The exchange of the structural water of collagen for alcanols was investigated using X -ray diffraction combined with mechanical measurements.

The stepwise dehydration with methanol, ethanol or 1-propanol is reflected by the reversible loss of the characteristic equatorial reflexions of native rat tail tendons.

The exchange for 1-alcanols in ascending homologous order is characterized by:

1. an increase in the distance between the axes of the triple helices depending on the number of carbon atoms of the alkyl chain,

2. a shortening of the long-spacing of 67 nm characteristic of native collagen and

3. the herewith correlated increase in tension on isometrically measured fibres.

The stepwise dehydration with 2-propanol leads first to a loss of the equatorial reflexions that are characteristic of native collagen, then to their reappearance at smaller diffraction angles. The exchange for 2-alcanols in ascending homologous order is characterized by:

1. a splitted equatorial reflexion at 4.1 ± 0 .1 nm, that stays constant up to 2-nonanol, and moves to 4 .8 - 5 .0 ± 0 .1 nm with more than 9 carbon atoms in the alkyl chain,

2. a shortening of the long spacing of 67 nm characteristic of native collagen and

3. the herewith correlated increase in tension on isometrically measured fibres.

Stereochemical requirements are discussed as well as consequences for the structural model of collagen.
Stimulation of Juvenile Hormone Biosynthesis in vitro by Locust Allatotropin
Authors: Ferenz Hans-Joerg , Diehl Ingrid
Published: August 2018

In Locusta migratoria the gonotrophic cycles are regulated by juvenile hormone. The cyclical changes of juvenile hormone synthesis in locust corpora allata seem to be regulated by a neuro-hormonal factor. Such an allatotropin could be extracted from corpora cardiaca and brains of Locusta migratoria. It is a small pronase-sensitive and heat-stable peptide. Extract of one corpus cardiacum stimulates corpus allatum biosynthetic activity in vitro 5 to 20-fold.
Notizen: Photosensitized Effects of Furocoumarins: the Possible Role of Singlet Oxygen
Authors: Vedaldi Daniela , Dall'Acqua Francesco , Gennaro Armando , Rodighiero Giovanni
Published: August 2018

The capacity of various furocoumarins to generate singlet oxygen in aqueous solution has been determined. The antiproliferative and the skin-photosensitizing activities of the same furocoumarins did not show any correlation with the capacity to generate the singlet oxygen, while these photobiological properties could be correlated with the capacity of furocoumarins to induce photolesions to the DNA.
Herbicide/Quinone Binding Interactions in Photosystem II
Authors: Vermaas Wim F. J. , Renger Gernot , Arntzen Charles J.
Published: August 2018

Many inhibitors prevent the oxidation of the primary electron-accepting quinone (QA) by the secondary quinone (Qв) in photosystem II by displacement of Qв from its binding site. On the other hand, plastoquinone-1 and 6-azido-5-decyl-2,3-dim ethoxy-p-benzoquinone displace herbicides. Binding studies show the herbicide/quinone interaction to be (apparently) competitive.

The herbicide binding is influenced differentially by various treatments. In this paper it is shown that the affinity of, for example, bromoxynil is decreased by thylakoid unstacking or by light-or reductant-induced reduction of certain thylakoid components, whereas atrazine affinity remains unchanged. Furthermore, absence of HCO-
3 in the presence of form ate leads to an affinity decrease of bromoxynil and atrazine, but to an increase in i-dinoseb affinity. Other differential photosystem II herbicide effects are known from the literature.

Since different and unrelated groups of Q-
A oxidation inhibitors have been found, and because of the above-mentioned dissimilarities in binding characteristics for different inhibitor groups, the hypothesis of non-identical, but “overlapping” binding sites for different herbicide groups and the native quinone must be more extensively defined. In this manuscript we evaluate both the competitive herbicide/quinone binding model, and a model in which binding of one ligand alters the protein conformation resulting in a dramatic decrease in the binding affinity of ligands from other chemical groups; in this model ligands from the same or related chemical groups bind competitively. Thus, the latter model proposes that only one herbicide or quinone molecule can be bound with high affinity to the herbicide/quinone binding environment, but it depends on the chemical structure of the ligands whether the binding interaction between two ligands is truly competitive or more indirect (allosteric), mediated through the protein conformation.
The Effects of Bicarbonate Depletion and Formate Incubation on the Kinetics of Oxidation-Reduction Reactions of the Photosystem II Quinone Acceptor Complex
Authors: Robinson Howard H. , Eaton-Rye Julian J. , Rensen Jack J. S. van , Govindjee
Published: August 2018

Chloroplast thylakoid membranes depleted of bicarbonate exhibit a slowed oxidation of the primary quinone acceptor (Qᴀ) by the secondary quinone acceptor (Qв) of photosystem II. The kinetics of these slowed reactions have been followed by using short xenon flashes of light both to excite photosystem II and to probe the redox state of Qᴀ. Thylakoids incubated with formate but not depleted of bicarbonate showed the same pattern of slowed reaction kinetics of the quinone acceptors as seen in bicarbonate-depleted| thylakoids. This led us to conclude that there was a simple competition between bicarbonate and formate at this site; however, steady-state electron transfer measured with an oxygen electrode showed that although the bicarbonate- depleted thylakoids were indeed inhibited, rates in the formate-incubated thylakoids were only slightly slowed. We suggest that the inhibition seen at the quinone acceptor site of photosystem II depends in a subtle way upon the rate of exchange of bicarbonate and formate at this site.
Identification of the Herbicide Binding Region of the Qв-Protein by Photoaffinity Labeling with Azidoatrazine
Authors: Wolber Paul K. , Steinback Katherine E.
Published: August 2018

Spinach thylakoids have been photoaffinity labeled with [14C]azidoatrazine in vitro and with specific [3H]amino acids in vivo. The radiolabeled protein has been isolated, cleaved with trypsin, and the resulting fragments have been identified by their characteristic [3H]amino acid incorporation. The peptide pattern has been interpreted using the known gene sequence for the QB-protein of spinach thylakoids, which is the major protein labeled by both the in vivo and in vitro procedures. When analyzed by gel filtration, over 80% of the 14C-activity migrated as two peaks: one as undigested protein at the void volume and the other at an apparent MW of 8.35 ± 0.76 kilodaltons. The remaining activity migrated with the included volume as free azidoatrazine. Fragments were analysed for covalent [14C]azidoatrazine binding; the tryptic peptide covalently labeled by [14C]azidoatrazine was found to be the fragment Pro-141 to Arg-225. This peptide is well removed from the site of a single amino acid change at Ser-264 implicated in triazine resistance, but includes a region suggested to be involved in Qв-binding by homology with sequences of two reaction center proteins from Rhodopseudomonas capsulata.
Isolation of 32-35 kDa Thylakoid Proteins from Chlamydomonas reinhardii
Authors: Pucheu N. , Wildner G. F.
Published: August 2018

The protein composition of Chlamydomonas reinhardii thylakoids in the molecular weight range of 32-35 kDa was studied. The thylakoids were labelled with 32P-Pi in vivo using Pi-starved cell cultures, solubilized with SDS and separated by polyacrylamide gradient gel electrophoresis. The following differentiation of proteins could be accomplished: two proteins were phosphorylated, which were also well stained with Coomassie blue, and one major protein was only detected by the silver staining procedure. The mobility of the latter protein is different in gels with urea, showing an apparently lower molecular weight.

In order to investigate whether a functional photosystem II is obligatory for protein phosphorylation, the phosphorylation of thylakoid proteins was studied with a photosystem II deficient mutant. The mutant, which had normal photosystem I activity, but lacked photo- system II activity, could synthesize ATP light dependently; its main labelled protein bands had a molecular weight of 32-35 kDa; it contained the light harvesting protein chlorophyll complex and an unknown protein at 22 kDa. The 32P incorporation in photosystem II deficient cells was comparable to cells with functional photosystem II units.
Inhibition of Phytoene Desaturase – the Mode of Action of Certain Bleaching Herbicides
Authors: Sandmann Gerhard , Clarke Ian E. , Bramley Peter M. , Böger Peter
Published: August 2018

Assay systems have been developed in order to differentiate between the modes of action of certain bleaching herbicides. These include inhibition of chlorophyll or carotenoid biosynthesis, and initiation of pigment degradation. Herbicidal compounds with phytoene desaturase as their primary target site were investigated in a cell-free carotenogenic system from Aphanocapsa. In a comparative study, the structural prerequisites for inhibition of phytoene desaturase were established for both benzophenone analogs and various m-phenoxybenzamides. This inhibitory action of the latter compounds is enhanced by lipophilic groups with certain steric properties.
Chemical Defense of Lupins. Mollusc-Repellent Properties of Quinolizidine Alkaloids
Authors: Wink Michael
Published: August 2018

Polyphagous molluscs such as Helix pomatia and Arion rufus generally do not feed on plants containing alkaloids. Of 19 species tested 10 species were totally avoided, the other 9 species were less attacked than Lactuca sativa, which was readily taken. Plants containing quinolizidine alkaloids were studied in detail. Those species with the α-pyridone alkaloids cytisine and N-methylcytisine were avoided to a higher extent than plants with lupanine as the major alkaloid. Since the repellency observed could be due to other natural products present in the plants besides the alkaloids, the feeding response of Helix pomatia was tested on artificial diets containing quinolizidine alkaloids in various concentrations as the only variable. If the snails had the choice they clearly preferred alkaloid-free food or a diet with only low alkaloid concen­trations. Half-maximal repellency of cytisine is less than 2 mᴍ, of sparteine 1-5 mᴍ, and of lupanine 1-8mᴍ. Since the in vivo concentrations of sparteine, cytisine, and lupanine are equal to or higher than the inhibitory concentrations required it is concluded that quinolizidine alkaloids constitute a potential antimolluscan principle of legumes.
Control of Fatty Acid Incorporation into Chloroplast Lipids in vitro
Authors: Sauer Andreas , Heise Klaus-Peter
Published: August 2018

1.In isolated chloroplasts which are provided with essential exogenous substrates for glycerolipid biosynthesis (sn-G3P and UDPgal) the incorporation of fatty acids into lipids shows the same pH dependence as the fatty acid synthesis itself with a stromal pH optimum close to 8.5.

2.Furthermore high rates of glycerolipid biosynthesis appear to be accompanied by a preferred oleate incorporation as compared to palmitate.

3.Reinvestigations of the sn-G3P requirement of plastid lysophosphatidic acid formation with rapidly prepared substrate-free chloroplast extracts under approximately physiological conditions reveal a lower specificity of the primary sn-G3P acylation for oleate, as recently found for the fatty acid transfer from purified acyl-ACP fractions on to sn-G3P, catalyzed by purified acyl transferase 1.

4.A comparison of calculated stromal sn-G3P levels under physiological conditions (0.1- 0.3 mᴍ) with those, required for half saturation of the primary acylation reaction either with oleate (Km(sn-G3P) = 0.3 mᴍ) or palmitate (Km (sn-G3P) = 0.6 mᴍ) in chloroplast extracts suggests, that both fatty acids to be involved in lysophosphatidic acid formation within chloroplasts, although oleate would be preferred.

5.The latter observation facilitates the understanding of a palmitate accumulation in chloroplast lipid fractions, induced by increasing sn-G3P concentrations in chloroplast sus­pensions. 6.Although stimulating fatty acid synthesis from acetate in intact chloroplasts, acyl-CoA- synthesizing-conditions (presence of CoA and ATP) in the applied chloroplast extracts appear to inhibit fatty acid incorporation into sn-G3P and thus to exert a regulatory function between the plastidary and extraplastidary glycerolipid biosynthesis.
Packing Pattern of DNA in Bacteriophage T2
Authors: Ghosh A N. , Sen A. , Gupta N. N. Das
Published: August 2018

Osmotic shock was applied to phage T2 in such a manner that the compact-mass of DNA was released from phage. The shape of this compact-mass of DNA was studied under electron microscope. It appeared that the DNA was packed into an elongated icosahedron similar to the phage head.
Biosynthesis of the Bufadienolide Ring of Scillirosid in Scilla maritima
Authors: Galagovsky L. R. , Porto A. M. , Burton G. , Gros E. G.
Published: August 2018

Administration of sodium [1,2-14C2]oxaloacetate and sodium [1-14C] acetate to Scilla maritima plants yielded labelled scillirosid. Asystematic degradation of scillirosid indicated that the 2 -pyrone ring of the bufadienolide is formed by the condensation of a pregnane derivative (derived from mevalonic acid via squalene) and one molecule of oxaloacetic acid.
Ein Adsorbens als Speicher für Phytohormone in einer pflanzlichen Suspensionskultur / An Adsorbent as Phytohormone Reservoir in a Plant Cell Suspension Culture
Authors: Beiderbeck Rolf , Knoop Bernd
Published: August 2018

The addition of an adsorbent (activated charcoal) to plant cell suspension cultures often decreases the growth rate, in a tobacco cell culture accom panied by alterations of protein content and cell size. All these effects can be reversed in part or even totally after pretreatment of the adsorbent with phytohormones.
Inhibition by Sethoxydim of Chloroplast Biogenesis, Development and Replication in Barley Seedlings
Authors: Lichtenthaler Hartmut K. , Meier Dieter
Published: August 2018

Chloroplast Biogenesis, Inhibition of Chloroplast Replication, Sethoxydim. Sun-Type Chloroplast Sethoxydim not only blocks leaf growth and development of barley seedlings but also inhibits chloroplast biogenesis at all stages of development from proplastids to prochloroplasts, young and mature chloroplasts. Not only thylakoid synthesis, thylakoid multiplication and grana for­mation are affected, but also chloroplast replication. The chloroplasts of secondary leaves which before the sethoxydim application are in the stage of young, developing chloroplasts, remain in this differentiation stage when treated with sethoxydim. With their ultrastructural characteristics (e.g. lower stacking degree, higher proportion of exposed membranes, a lower thylakoid frequency etc.) they resemble sun-type chloroplasts. In the shoot meristem sethoxydim-treated plants contain only proplastids, whereas the plastids in the shoot meristem of control plants are already in the developmental stage between prochloroplasts to young chloroplasts. Mesophyll cells of sethoxydim-treated plants contain only one third of the chloroplasts found in the controls.
Fusion of Large Unilamellar Liposomes Containing Hemocyanin with Planar Bilayer Membranes
Authors: Pasquali Flavia , Menestrina Gianfranco , Antolini Renzo
Published: August 2018

Large unilamellar vesicles were prepared by detergent removal from micelles containing phosphatidylcholine, phosphatidylethanolam ine and phosphatidylserine. Liposomes were then interacted with Megathura crenulata hemocyanin, a well studied channel former. Incubation of the resulting proteoliposomes on one side of a phosphatidylserine-containing planar bilayer under fusion conditions yielded strong current increases. Such increase is due to insertion of ionic channels from the liposomes into the planar bilayer. Studying the effects of Ba2+ on the electrical properties of the channel we could show that the protein is always inserted into a bilayer during this process, i.e. fusion of proteoliposomes with the artificial membrane occurs. The strong non linearity of the current-voltage curve of the hemocyanin pore could be used as a probe of the extent to which fusion preserves the orientation of the channel through the bilayer.
The Triton X-100 and High Salt Resistant Residue of Saccharomyces cerevisiae Nuclear Membranes, II / Isolation of the Nuclear Membrane Insoluble Residue from G1 Arrested Cells and Immunological Comparison with the Corresponding Vertebrate Nuclear Fraction
Authors: Mann Karlheinz , Mecke Dieter
Published: August 2018

Isolation of the Nuclear Membrane Insoluble Residue from G1 Arrested Cells and Immunological Comparison with the Corresponding Vertebrate Nuclear Fraction The Triton X-100 and High salt resistant residue of the nuclear envelope of Saccharomyces cerevisiae cells arrested in the G 1 phase of cell cycle with a mating pherom one was isolated. It showed the same electrophoretic protein pattern as the insoluble residue isolated from log-phase cells. Examination of nitrocellulose blots of nuclear protein fractions with antiserum raised against a vertebrate lamin failed to show any immunological cross-reaction.
Intranuclear Crystals in the Intestinal Epithelium of the Snail Marisa cornuarietis (Prosobranchia)
Authors: Lutfy Ramsis G. , Ruthmann August
Published: August 2018

Filamentous intranuclear crystals consisting of two sets of intersecting sheets are common in the intestinal epithelium. They are closely associated with chromatin granules but electron microscope cytochemistry using a modified Feulgen procedure did not show DNA in the crystal itself. Light microscope histochemical tests indicated that the crystals consist of protein.
Inheritance of mitochondrial DNA in Oenothera berteriana and Oenothera odorata Hybrids
Authors: Brennicke Axel , Schwemmle Berthold
Published: August 2018

Restriction patterns of mitochondrial DNAs (mtDNA) from different Oenothera berteriana and Oenothera odorata bastards are compared and the identity of mtDNA in hybrid forms with different com binations of nuclear, Filastid, and mitochondrial genom es has been determined, nheritance of m tDNA in these hybrids follows the pattern predicted by the genetic analysis. One hybrid is shown to nave a Oenothera berteriana nuclear and plastidal genom e with a mitochondrial genome of the Oenothera odorata type.
A New Cembranoid from Tobacco, IV *
Authors: Heemann Volker , Bylov Anne-Marie , Hass Werner , Kahre Claudius , Seehofer Friedlieb
Published: August 2018

4,8-Dimethyl-11-isopropyl-6,8-dihydroxy-pentadeca-4,9-dien-14-on-1-al (3) was identified as a new natural product from tobacco. 3 was isolated from the surface gum of fresh tobacco. The spectral data, chemical properties and the synthesis 3 are given.
Studies on the O2 Evolution under Flash Light Illumination in Preparations of Anacystis nidulans
Authors: Pistorius E. K. , Schmid G. H.
Published: August 2018

The O2 yield under flash light illumination in preparations of Anacystis nidulans was examined in the presence of redox components such as ferricyanide and ferrocyanide. When ferricyanide (1 mᴍ) was added to the lyophilized, lysozyme treated and EDTA washed cells of A. nidulans the familiar Joliot-Kok oscillalion with maximum on the third flash and periodicity of four was observed (in the presence of added CaCl2 and MnCl2). However, when the ferricyanide con­centration was increased to about 8 mᴍ , a reduction of the O2 evolution under flash illumination was observed, and an O2 uptake could clearly be seen under the first and second flash. This O2 uptake was inhibited by DCMU and o-phenanthroline, but was not influenced by KCN or salicylhydroxamic acid. As ferrocyanide was progressively added to 1 mᴍ ferricyanide, the oscillations faded out and the steady-state O2 evolution decreased. Light would progressively increase the O2 evolution and reduce the damping of the oscillations.

Two patterns of O2 evolution under short saturating light flashes were observed with these Anacystis preparations on first illumination in the presence of cations but in the absence of ferricyanide. One pattern corresponded to the typical pattern which has been repeatedly described in the literature, but the second pattern gave the indication of an initial “over-reduced” state of the photosystem II reaction center. With suitable procedures the two patterns were interchangeable. Moreover, the effect of ʟ-arginine on the flash pattern was examined. The results are discussed in connection with the possible dual function of the previously described flavin protein as an ʟ-amino acid oxidase and as a component of the O2 evolving reaction center (E. K. Pistorius and H. Voss, Eur. J. Biochemistry 126,203-209 (1982)).
Light Induced Changes in the Conformation of Spinach Thylakoid Membranes as Monitored by 90° and 180° Scattering Changes: A Comparative Investigation
Authors: Coughlan S. J. , Schreiber U.
Published: August 2018

A series of investigations on light induced thylakoid membrane conformational changes has been carried out using scattering changes measured either at 90° or 180° (transmittance changes) as criteria for changes in membrane structure upon illumination. These two phenomena were found to react similarly to a range of photosynthetic inhibitors, to changes in the ionic (Mg2+, H+) concentration, and to have similar difference spectra. However, it was found possible to distinguish these two phenomena by the differences in the kinetics of the light induced rise times. This could be shown most clearly using an Aminco DW2 spectrophotometer with the measuring beam deflected through 90° by front face mirrors. The dark decay time of the two scattering changes was similar.

These results are discussed in relation to the hypothesis that the light induced narrow angle 90° scattering response represents microconformational membrane changes in response to proton uptake, and the 180° scattering changes represent a mixed response including changes in the stacking of thylakoids.
Haemolytic Properties of Cereal 5-n-Alk(en)ylresorcinols
Authors: Kozubek Arkadiusz
Published: August 2018

The haemolytic activity of 5-n-alk(en)ylresorcinols is temperature dependent and correlated to their transition temperatures. The values of the parameters describing the 5-n-alk(en)yl-resorcinol-induced red blood cell lysis indicate strong affinity of the compounds to the membrane and their high lytic capacity. The affinity of the compounds for the membrane decrease with the increasing quantity of the molecules incorporated into the erythrocyte membrane and is much higher for saturated resorcinols than unsaturated ones. The amount of 5-n-alk(en)ylresorcinol molecules bound to the membrane at a hundred percent lysis is about eighty times and eleven times (for alkyl and alkenyl derivatives respectively) higher than at zero percent lysis. Estimated free energy of erythrocyte lysis was similar for alkyl and alkenyl derivatives of resorcinol provided the preparation of the resorcinolic suspensions above their transition temperatures.
Feeding and Molt Inhibition by Azadirachtins A, B, and 7-Acetyl-azadirachtin A in Rhodnius prolixus Nymphs
Authors: Garcia Eloi S. , Azambuja Patricia de , Forster Hans , Rembold Heinz
Published: August 2018

The antifeedant and antimolting effects of azadirachtins A and B, and of a synthetic derivative, 7-acetyl-azadirachtin A were examined. Given through a blood meal, the effective dose (ED50) for the antifeedant effect ranged from 25 to 30 μg/ml of blood for the three compounds. ATP, a phagostimulant, also given orally, reversed the antifeedant action of azadirachtin A. The ED50 values for molt inhibition were 0.04, 0.015, and 0.45 (μg/ml of blood for azadirachtins A, B, and 7-acetyl-azadirachtin A, respectively. The mechanisms of feeding and molt inhibitions by azadirachtin A B, and its 7-acetyl-azadirachtin A derivative are discussed.
Two Different Pathways Leading to Phenanthrenes and 9,10-Dihydrophenanthrenes of the Genus Dioscorea
Authors: Fritzemeier K.-H. , Kindi H. , Schlösser E.
Published: August 2018

The bibenzyl batatasin III was formed de novo in aerial bulbils and tubes of Dioscoreaceae from dihydro-m-coumaric acid. In cell-free preparations, bibenzyl synthase activity and an O-methyltransferase converting 3,3′,5-trihydroxybibenzyl into batatasin III were detected. High rates of incorporation of dihydro-m-coumaric acid into a 9 ,10-dihydrophenanthrene (hircinol) showed that a pathway being known to occur in orchids is also effective in Dioscoreaceae. The biosynthesis of hircinol could be stimulated by infecting the aerial bulbils with various fungi. In parallel to the dihydro-w-coum aric acid pathway another biosynthetic reaction sequence leading to phenanthrenes was found to occur. The pathway was established in its principal steps: p-coumaric acid - trihydroxystilbene (resveratrol) - phenanthrene (batatasin I or iso-batatasin I)
Volatile Sulfur Compounds Produced by Methionine Degrading Bacteria and the Relationship to Concrete Corrosion
Authors: Pohl Manfred , Bock Eberhard , Rinken Marian , Aydin Mitat , König Wilfried A.
Published: August 2018

Pseudomonas fluorescens, Proteus vulgaris, and Serratia marcescens, members of the microflora of soil and waste water, attacked methionine in the presence of glucose. The sulfur of methionine was released as methane thiol, dimethyl sulfide and dim ethyl disulfide. The volatile sulfur com pounds were qualitatively and quantitatively investigated by gas chromatography. Dimethyl disulfide was formed of methane thiol by various bacteria to a different extent. Growing in the presence of oxygen, S. marcescens oxidized most of the m ethane thiol to dim ethyl disulfide. In the presence of glucose. P. fluorescens dissimilated m ethionine with production of m ethane thiol and dimethyl disulfide. The dissimilation was stimulated with decreasing glucose concentration