bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Neurotransmitters on Movement of Screening Pigment in Insect Superposition Eyes
Authors: Hamdorf Kurt , Höglund Gunnar , Juse Achim , Stusek Peter 
Published: August 2018

Abstract
Com pound Eye, Pigment Migration, Adrenaline, Octopamine, Noradrenaline The light-induced expansion of the screening pigment in the com pound eyes of the sphingid moth Deilephila and the owlfly Ascalaphus is counteracted by local application of noradrenaline or octopamine. Ata critical concentration, similar for both drugs, the expanding effect caused by a light stimulus is completely neutralized, and at higher drug concentrations light stimulation induces a contraction of the screening pigment. The contracting effect of noradrenaline and octopamine is counteracted by adrenaline. None of the other putative neuroactive substances tested (acetylcholine, GABA , histamine, melatonin, serotonin and taurine) has a com parable effect on light-induced pigment movement. It is hypothesized that pigment migration is controlled by a system of antagonistically acting catecholamines, similar to the noradrenaline/adrenaline system present in vertebrates.
The Essential Root Oil of Peucedanum lancifolium Lange and Chemotaxonomic Implications
Authors: Kubeczka K.-H. , Schmaus G. , Schultze W. , Ullmann I. 
Published: August 2018

Abstract
The composition of the essential root oil of Peucedanum lancifolium Lange (A piaceae), growing in the Atlantic coast regions of France, North-West Spain und Portugal was investigated by chromatographic and spectroscopic methods. Forty five terpenoids, many of them of already known structure, and several aliphatic esters have been identified. Besides the main constituent, the irregular sesquiterpene alcohol trans-sesquilavandulol, representing 53.37% of the total oil, some hitherto unknown sesquiterpenoids with an irregular carbon skeleton were found. The possible chemotaxonomic value of the essential oil com position with regard to the close botanical relationship of Peucedanum lancifolium Lange and Peucedanum palustre (L .) M oench is briefly discussed. With the exception of these two species, trans-sesquilavandulol was not found in any other member of the genus Peucedanum.
Theoretical Investigations on the Role of Steroid-Skeleton C4 = C5 Unsaturation in Competitive Aromatase Inhibition
Authors: Bohl Martin , Simon Zeno , Lochmann Jens Reiner 
Published: August 2018

Abstract
A quantitative structure-activity relationship (QSAR ) approach by use of the minimal topological difference (MTD) method including 46 derivatives of 4-androstene-3,17-dione and 5a-androstane- 3,17-dione is applied to give indications about the role of the C 4 = C5 double bond in competitive inhibition of human placental aromatase and about sterical requirements in steroidaromatase interactions. The inhibitory activity is found to correlate with the sterical MTD variable, hydrophobicity, and π-system conjugation in the A,B-ring region.
A comparison of the MTD results reveals a good agreement with interpretations based on freeenergy data derived from inhibition constants.
By means of MM2 molecular mechanics and PCILO quantum-chemical calculations, the 4-ene structure is shown to significantly influence conformational features of C19 substituents which are important in enzym atic transformations. While 19-hydroxy-5a-androstane-3,17-dione favour a conformation having the hydroxyl group in the enzyme-directed out-of-ring position, the C 4 = C5 double bond energetically enables the steroid to adopt a conformation which can be hydroxylated without internal rotations.
According to present theoretical findings, the 4-ene unsaturation thus exerts an indirect conformational influence by hydroxyl positioning appropriate to aromatase interactions and a direct electronic influence by π conjugation.
Photochemical and Non-Photochemical Quenching of Chlorophyll Fluorescence Induced by Hydrogen Peroxide
Authors: Neubauer Christian , Schreiber Ulrich 
Published: August 2018

Abstract
Chlorophyll Fluorescence. Fluorescence Quenching, Hydrogen Peroxide. Active Oxygen. Ascorbate Peroxidase Chlorophyll fluorescence quenching induced by H 20 2 in intact spinach chloroplasts was investi­gated with a modulation fluorometer which allows to distinguish between photochemical and non­ photochemical quenching components by the so-called saturation pulse method. Residual catalase activity was removed by washing and percoll gradient centrifugation. H2O2 was found to induce pronounced photochem ical and non-photochemical quenching, characteristic for the action of a Hill reagent, with a half-maximal rate already observed at 5 × 10-6 m . The saturation characteris­tics and maximal rate of H2O2-reduction were very similar to those of methylviologen reduction. H2O2-dependent quenching was stimulated by ascorbate and inhibited by cyanide and azide in agreement with previous findings by other researchers that H2O2-reduction involves the ascorbate peroxidase scavenging system and that the actual “Hill acceptor” is an oxidation product of ascorbate, i.e. monodehydroascorbate or dehydroascorbate. With well-coupled intact chloro­plasts reducing CO2 at 150 (μmol (mg Chl)-1h-1, iodoacetamide stopped CO2-dependent O2-evolution and consequent addition of 10″3 m H2O2 produced an O2-Solution rate of 240 (μmol (mg Chl)-1h-1 .It is concluded that light-dependent H 20 2 reduction is a very efficient reaction in intact chloroplasts. As H2O2 formation and consequent reduction also occur in vivo, the corre­sponding quenching should be considered when assimilatory electron flow is estimated from quenching coefficients. It is suggested that proton flux associated with H2O2-formation and reduc­tion may be important for the adjustment of appropriate ATP /NADPH ratios required for CO2-fixation in vivo. Furthermore, H2O2-reduction may serve as a valve reaction whenever Calvin cycle activity is limited by factors different from NADPH supply, thus protecting against photo-inhibitory damage.
In vitro Binding of Nitracrine to DNA in Chromatin
Authors: Wilmańska Dorota , Szmigiero Leszek , Gniazdowski Marek 
Published: August 2018

Abstract
In the presence of sulfhydryl compounds nitracrine, an anticancer drug, binds covalently to DNA . The accessibility of DNA in chromatin both to nitracrine and to 8-methoxypsoralen. which was used as a reference compound in this study, when assayed in NaCl concentrations from 0 to 2 m show similar characteristics. The initial decrease reaches a minimum at 0.15 m NaCl above which dissociation of non-histone proteins and histones at higher ionic strengths is demonstrated by an increase in accessible sites. The relative accessibility of DNA in chromatin to nitracrine is, however, lower than that found for 8-methoxypsoralen. Partial dissociation of chromatin with 0.7 m NaCl increases the accessibility of DNA in chromatin when assayed in the absence of NaCl but has no apparent influence when estimated at ionic strength close to physiological conditions.
Flavonoid Aglycones in the Leaf Exudate of the Genus Leucocyclus (Compositae)
Authors: Valant-Vetschera Karin M. , Wollenweber Eckhard 
Published: August 2018

Abstract
The monotypic genus Leucocyclus, consisting of only two subspecies, was investigated for its exudate flavonoids. Major flavonoid aglycones were polymethoxyderivatives of 6-hydroxyflavones and, to a lesser extent, of 6-hydroxyflavonols. The two subspecies differed in their accumula­tion trends, but populational variation reduced the significance of taxonomic implications. Cultivated material corre­sponded largely to the original material collected from nature. The accumulation trends of Leucocyclus coincide with those of the closely related genus Achillea.
Fatty Acid Composition in the Lipids of some Marine Chiorococcales and Eustigmatales
Authors: Menzel Karola , Wild Aloysius 
Published: August 2018

Abstract
The fatty acid composition in the lipids of six coccoid microalgae species (≈ 2 μm in diameter) was investigated. In addition to analyses of ultrastructure and pigment content, lipid composition is shown to be a chemotaxonomic tool in the classification of algae. The four species of Chiorococcales (Chlorophyceae) - the marine species as well as the fresh water species, both kept in artificial seawater - contain a fatty acid composition resembling that of Chlorella spp. and of green leaves of higher plants. The fatty acid pattern is characterized as lacking in C20 acids but containing large amounts of C 16 and C 18 polyunsaturated fatty acids, hexadecatrienic acid (16 :3) and a-linolenic acid (18:3ω3) in particular. In contrast the two species of Eustigmatales (Eustigmatophyceae) investigated here show a deficiency of the C 16 and C 18 polyunsaturated fatty acids but contain large amounts of eicosapentaenic acid (20:5).
Purification and Properties of Arogenate Dehydrogenase from Actinoplanes missouriensis
Authors: Hund Hilda-K. , Bär Gerda , Lingens Franz 
Published: August 2018

Abstract
Actinoplanes missouriensis utilizes arogenate as an intermediate in ʟ-tyrosine biosynthesis, while no evidence of prephenate dehydrogenase was observed. Arogenate dehydrogenase has been partially purified by a five-step procedure. The enzyme requires NAD as cofactor. The Km values for NAD and arogenate are 0.2 mм and 0.15 mм, respectively. The molecular weight of arogenate dehydrogenase is about 68,000, and SDS gel electrophoresis indicates a composition of two identical subunits. The enzyme is not feedback inhibited by ʟ-tyrosine and unaffected by ʟ-phenylalanine, prephenate, phenylpyruvate, p-hydroxyphenylpyruvate or ʟ-tryptophan. Arogenate dehydrogenase is quite sensitive to p-hydroxymercuribenzoate with 50% inhibition at 12.5 μм of the SH -specific reagent. The presence of malate in usually applied arogenate preparations is demonstrated and the consequence of an impure substrate on arogenate dehydrogenase studies is discussed.
Stimulation of Myoblast Membrane Protein Synthesis by 25-Hydroxy-Vitamin D 3
Authors: Bellido Teresita , Boland Ricardo 
Published: August 2018

Abstract
The effects of 25-hydroxy-vitamin D3 (25 OHD3) on myoblast protein synthesis were studied in connection with its role on muscle cell phosphate metabolism . The sterol markedly increased leucine incorporation into total cell proteins in cultured chick embryo myoblasts. This enhance­ment was greater than that produced by 1,25-dihydroxy-vitamin D3 (1,25(OH)2D3) and occurred prior to a significant stimulation of cell phosphate accumulation. Maximum effects of 25 OHD3 (8 h) on myoblast phosphate uptake were suppressed by cycloheximide indicating that they are mediated by de novo protein synthesis. At a similar treatment period, labelling of myoblasts with [3H]leucine (control) and [14C]leucine (+ 25 OHD3) followed by co-electrophoresis of total protein extracts on SDS-PAGE and isoelectrofocusing gels revealed that the sterol selectively affects the synthesis of proteins of 20 kDa and 50 kDa. These macromolecules were recovered in the microsomal fraction after differential centrifugation of homogenates. Further fractionation of myoblast microsomes on sucrose density gradients show ed co-localization of the 50 kDa and 20 kDa proteins with microsomal subfractions which preferentially bind [3H -alpha]bungarotoxin, suggesting that the proteins induced by 25 OHD3 are associated to plasma membranes and may play a role in the effects of the sterol on cell phosphate uptake.
Amino Acid Substitutions in the D1 Protein of Photosystem II Affect QB
-Stabilization and Accelerate Turnover of D1
Authors: Ohad Nir , Amir-Shapira Dekel , Koike Hiroyuki , Inoue Yorinao , Ohad Itzhak , Hirschberg Joseph 
Published: August 2018

Abstract
Isogenic strains of Synechococcus PCC 7942 were genetically engineered so that copy I of the gene psbA was mutated at specific sites. These mutations resulted in replacements of Ser 264 by Gly or Ala and of Phe 255 by Tyr or Leu in the D1 protein. The mutants were resistant to herbicides inhibiting electron transfer in photosystem II. All mutants exhibited alterations in the stability of QB
- as demonstrated by a temperature downshift, to various extents, of the in vivo thermoluminescence emission. Measurements of the light-dependent turnover of D1 showed a marked decrease in the t 1/2 of this protein in the mutants as compared to wild-type, under low to medium light intensities. A correlation was found between the degree of pertur­ bation in the QB
- stability and the rate of acceleration in the turnover of D1. These data pro­ vide a direct evidence for the overlapping binding sites for the plastoquinone B and herbicides in the D1 protein. In addition these data indicate a close link between QB
- destabilization in reaction center II and the mechanism controlling the light-dependent turnover of D1. Based on these results and previous work we suggest that destabilization of the semireduced quinone, facilitates a light-induced damage in D1 which triggers its degradation.
Targeted Deletion Mutagenesis of the β Subunit of Cytochrome b559 Protein Destabilizes the Reaction Center of Photosystem II
Authors: Pakrasi Himadri B. , Nyhus Karin J. , Granok Howard 
Published: August 2018

Abstract
Oligonucleotide-directed mutagenesis techniques were used to delete the psbF gene, encoding the β subunit of the cytochrom e b559 protein of the photosystem II complex in the cyano­ bacterium, Synechocystis 6803. Cyt b559 is an integral com ponent of PS II complex. However, its precise functional role in PS II remains to be determined. Previously, we created a mutant in which the psbF gene as well as three of its neighbouring genes, psbE , psbL and p sb i were simultaneously deleted from the chrom osom e of Synechocystis 6803 (Pakrasi, Williams and Arntzen, EMBO J. 7, 325 -332 , 1988). This mutant had no PS II activity. However, the role of any one of the four individual gene products could not be determined by studying this mutant. The newly generated mutant, T 256, had only one gene, p sbF , deleted from the genome. This mutant was also impaired in its PS II activities. In addition, it had barely detectable levels of two other protein com ponents, D1 (herbicide binding protein) and D2, of the reaction center of PS II, in its thylakoid membranes. In contrast, two other proteins of PS II, CP47 and CP43 were present in appreciable amounts. Fluorescence spectra (77 K) of the mutant showed the absence of a peak at 695 nm that was previously believed to originate from CP47. In addition, phycobilisomes, the light-harvesting antenna system of PS II, were found to be assembled normally in this mutant. We conclude that the presence of the β subunit of Cyt b559 in the thylakoid membranes is critically important for the assembly of PS II reaction center.
Hybrid Origin of Populus * jackii Confirmed by Gas Chromatography-Mass Spectrometry Analysis of Its Bud Exudate
Authors: Greenaway W. , Davidson C. G. , Scaysbrook T. , May J. , Whatley F. R. 
Published: August 2018

Abstract
Bud exudate of Populus balsamifera contains an array of characteristic compounds. Bud exudate of P. deltoides contains a different array of characteristic compounds. The exudate of P. x jackii contains compounds characteristic of both P. balsamifera and P. deltoides, indicating its hybrid origin.
Comparative Investigation on Formation and Accumulation of Rare Phenylpropanoids in Plants and in vitro Cultures of Pimpinella major
Authors: Merkel B. , Reichling J. 
Published: August 2018

Abstract
Unorganized callus and leaf/root-differentiating callus cultures of Pimpinella major have been established in liquid nutrient medium. Their capacity to accumulate rare phenylpropanoids such as epoxy-pseudoisoeugenol tiglate, epoxy-anol tiglate and anol tiglate was compared with that of seedlings and whole plants. The unorganized callus cultures were not able to accumulate any phenylpropanoids. In comparison, the leaf/root-differentiating callus culture promoted the accumulation of epoxy-pseudoisoeugenol tiglate (up to 90 mg/100 g fr.wt.) but not that of anol-derivatives. The accumulated amount of EPT in PMD-SH was comparable with that in plant seedlings.
Characterization of Conformers of D 1 of Photosystem II Using Site-Directed Antibodies
Authors: Besford R. T. , Thomas B. , Huskisson N. S. , Butcher G. W. 
Published: August 2018

Abstract
Antibodies have been raised to synthetic peptides, corresponding to a region in the loop spanning helices 4 and 5 of D 1 protein (Ala 250-Phe 265) and to a region anticipated to be near the C terminus of mature D 1 (His 332-Ala 345). Polyclonal antibodies to the sequence His 332-Ala 345 reacted with a 32 kDa polypeptide in thylakoid preparations identified as D 1 from its resistance (pea) or susceptibility (wheat) to lysine-C degradation. A monoclonal antibody to His 332-Ala 345 reacted preferentially with a faster migrating polypeptide in SDS electrophoresis, a putative conformer of D 1. Polyclonal antibodies to the sequence Ala 250- Phe 265 also reacted with the faster running polypeptide but not with the population of molecules running at 32 kDa. The putative conformer of D 1 from wheat appears to be more resistant than the main D1 population to lysine-C degradation. Peptide analyses by Takahashi et al. [(1988) FEBS Lett, 240, 6 - 8 ] suggest Asn 335-Ala 344 lies at the processed C terminus. The present report provides immunological confirmation that this sequence is retained in mature D 1.
Efficacy of Different Hexacyanoferrates(II) in Inhibiting the Intestinal Absorption of Radiocaesium in Rats
Authors: Dresow Bernd , Nielsen Peter , Heinrich Hellmuth C. 
Published: August 2018

Abstract
The inhibitory effect of various oral doses of different hexacyanoferrate(II) compounds (HCF) and the influence of the time interval of HCF-administration on intestinal 134Cs-absorption was studied in rats. Optimum inhibition was obtained by administration of HCF together with or 2 min before oral 134Cs loading. Using appropriate low amounts (0.1 -0.5 mg) of the different HCF compounds, the inhibitory effect increased in the sequence KZnHCF < KCuHCF < FeHCF < KCoHCF = KNiHCF < NH4FeHCF = KFeHCF . Oral administration of 5 mg (0.5 mg) of KFeHCF , together with 134CsCl loading, reduces 134Cs-absorption from 41 % (control) to 0.8% (2.8%).
Zinc-, copper-, cobalt, and nickel hexacyanoferrates(II), despite showing a high caesium sorption capacity in vitro, were less effective in rats and are not suited for in vivo application, also because they may produce toxic side effects. As a consequence, the orally administered colloidal-soluble iron (III) hexacyanoferrates(II) (NH4Fe[Fe(CN)6] and KFe[Fe(CN)6]) have to be considered as the most valuable countermeasure against radiocaesium absorption for humans and domestic animals in the case of a severe nuclear accident in the future.
Manganese oxide, a non-hexacyanoferrate(II) compound with known in vitro caesium binding capacity, showed no inhibitory effect on radiocaesium absorption in rats.
Ontogenetic Patterns in Amounts and Proportions of Dufour's Gland Volatile Secretions in Virgin and Nesting Queens of Lasioglossum malachurum (Hymenoptera: Halictidae)
Authors: Ayasse Manfred , Engels Wolf , Hefetz Abraham , Lübke Gunther , Francke Wittko 
Published: August 2018

Abstract
In the primitively eusocial sweat bee, Lasioglossum malachurum, 66 volatile compounds could be identified from queen Dufour’s gland secretions. The patterns found in gynes and in old nesting queens differed in the absolute amounts of extractable volatiles as well as in the relative proportions. 3-Methyl-3-butenyl octadecanoate is the main component in gynes, while 18-octadecanolide, 20-eicosanolide and 22-docosanolide largely dominate the bouquets of old queens. The probable roles of some specific compounds in pheromonal communication of mates and in nest recognition are discussed. Correlations with the volume of the fat body and the vitellogenic status of the ovary are described.
Short-Wavelength Absorbing Complexes of Chlorophyll a in Micellar Solution of Cationic Detergents
Authors: Schmidt A. , Gottstein J. , Scheer H. , Scherz A. 
Published: August 2018

Abstract
Micellar aggregates have been prepared from chloro­phyll a. Whereas most detergents including non-ionic, zwitterionic and anionic ones, produce aggregates with long-wavelength shifted and enhanced QY absorption, the cationic detergents hexadecyl-trimethylammonium-bromide and hexadecyl-pyridiniumchloride produce complexes with opposite traits: The QY absorption is shifted to shorter wavelengths, and it is hypochromic. The optical activity is increased as in the long-wave­ length shifted complexes, but the cd bands are non-conservative and coincide with the absorption maxima. The complexes are most likely small aggregates of chlorophyll with a changed geometry as compared to the “standard” ones.
A Survey of Alkaloids in Spartium junceum L. (Genisteae-Fabaceae)
Authors: Greinwald Roland , Lurz Gabriele , Witte Ludger , Czygan Franz-Christian 
Published: August 2018

Abstract
The alkaloid pattern of Spartium junceum has been investigated. Cytisine, N-methylcytisine, anagyrine, rhombifoline and epi-baptifoline occur as major compounds in most of the samples studied. Considerable quantitative differences were found between various parts of the plant. The alkaloid content changed strongly dependent on the seasons. Only a limited variation can be ascribed to geographical origin.
New Rotenoids from the Root Bark of Jamaican Dogwood (Piscidia erythrina L.)
Authors: Tahara Satoshi , Narita Eriko , Ingham John L. , Mizutani Junya 
Published: August 2018

Abstract
A further investigation of the root bark constituents of Jamaican dogwood (Piscidia erythrina) has revealed two new pyrano-rotenoids, (+)-erythynone and (+)-12a-hydroxyerythy-none. Both compounds co-occur with (-)-rotenone, and two additional rotenoids [(-)-12a -hydroxyrotenone and (-)-villosinol] not previously isolated from P. erythrina. Root extracts were also found to contain the rare isoflavone durmillone. The stereochemistry of all five Piscidia rotenoids was examined by ORD and CD spectrometry. These studies indicated that erythynone and 12 a-hydroxyerythynone were antipodal to naturally occurring (-) -6 aS; 12 aS-rotenone at the B/C ring junction.
Evidence for a Vacuolar-Type Proton ATPase in Entamoeba histolytica
Authors: Löhden-Bendinger Ursula , Bakker-Grunwald Tilly 
Published: August 2018

Abstract
Entamoeba histolytica Entamoeba histolytica is a primitive eukaryote that lacks mitochondria, Golgi and a well-developed endoplasmic reticulum. Close to half of the cell volume is occupied by pinocytic vesicles, which are in continuous turnover with the plasma membrane and perform functions that in higher eukaryotic cells are taken over by lysosomes. Similar to the latter, the amebal vesicles are acidified. We report here that bafilomycin AI, a specific inhibitor of vacuolar-type (V-) ATPases, suppressed this acidification at submicromolar concentrations; concom itantly, it inhibited pinocytosis. These results strongly suggest the presence of a V-ATPase in pinocytic vesicles of E. histolytica, and thereby support the notion that the V-ATPases in the organelles of higher eukaryotes are derived from an archaic plasma membrane-bound form.