bluuebunny/crossref_metadata_2025_split huggingface dataset:
DNA Content and Synthesis in Several Tissues and Variation of Moulting Hormone-Level in Gryllus bimaculatus DEG (Ensifera, Insecta)
Authors: Römer Franz , Eisenbeis Ilona 
Published: August 2018

The mode of growth of several tissues in Gryllus bimaculatus was investigated during postembryonic development by cytophotometric methods. In contrast to the situation in holo- metabolous insects, the tissues growing by endomitosis reach only moderate levels of polyploidy. In this case the growth of tissues is achieved by mitotic divisions of small cells with subsequent polyploidization.
The time courses of DNA synthesis were measured within the 3rd and, for comparison, the 8th larval instar by incorporation of labelled thymidine followed by autoradiography. Hemocytes, cells of the regeneration crypts of the midgut, gonads and nervous tissue showed a continuous incorporation rate; by contrast, DNA synthesis in other tissues was confined to a given time within the moulting cycle.
The changes in moulting hormone titre of the 3rd larval instar were investigated. The quantities of ecdysone and 20-OH-ecdysone were estimated by radioimmunoassay, and the hormones were identified by high pressure liquid chromatography (HPLC). The titre changes in time with at least 2 distinct maxima. The DNA synthesis periods are correlated with the hormone peaks, that of epidermis and tracheae with the first peak, and that of pylorus, ileum, rectum, Malpighian tubules and fat body with the second. DNA synthesis in prothoracic glands and oenocytes exhibits a time course that is the inverse of the hormone-secretion time course. The question whether moulting hormones have an influence on DNA synthesis is discussed.
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.
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
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
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.
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.
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

Abstract
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

Abstract
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.
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.
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.
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

Abstract
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.
Inhibition by Sethoxydim of Chloroplast Biogenesis, Development and Replication in Barley Seedlings
Authors: Lichtenthaler Hartmut K. , Meier Dieter 
Published: August 2018

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.