bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biochemical Activities of Propolis Extracts. I. Standardization and Antioxidative Properties of Ethanolic and Aqueous Derivatives
Authors: Volpert Regina , Elstner Erich F 
Published: August 2018

Abstract
Ethanolic extracts of Propolis are used as antiinflammatory and wound healing drugs since ancient times. In order to facilitate a comparison of different extracts, the standardization on the basis of quantitative determination of prominent components of these extracts has been substituted for simple biochemical “activity” tests. One of these activity tests bases on the in­ hibition of peroxidase-catalyzed oxidation of indole acetic acid indicating the presence of a defined mixture of monophenolic and diphenolic compounds. Other tests (diaphorase-catalyzed reductions and xanthine oxidase-catalyzed oxidations) demonstrate significant radical scavenging properties. Water-soluble extracts of propolis exhibit higher antioxidative and inhibitory activities as compared to the ethanolic extract.
Hydrogen Bonding of Cyanoacrylates with the D 1 Peptide
Authors: Phillips John N. , Banham Wendy K. 
Published: August 2018

Abstract
Representatives of two structural types of cyanoacrylate PS II inhibitors have been studied in respect to their pI50 values and qualitative rate of binding with wild type and S 264 G mutant thylakoids isolated from Brassica napus. Both are potent inhibitors of photosynthetic electron transport and both show a large discrimination between wild type and mutant thylakoids under equilibrium conditions. However one, an N-methylanilino cyanoacrylate, has an initial rapid reaction with both wild type and mutant thylakoids, but continues to react slowly with the wild type species until equilibrium is reached, while the other, a benzylamino cyanoacry­ late, equilibrates rapidly with both species as does the classical PS II inhibitor, atrazine. These differences in kinetic behaviour have been interpreted in terms of different H-bond interactions with the serine-264 hydroxyl group. It is suggested that the slow binding reaction is due to the N -methylanilino compound interacting as an H-bond acceptor with the serine-264 hydroxyl hydrogen thus disrupting an intramolecular ser-264-his-252 H-bond within the D 1 peptide. Rapid equilibration on the other hand, has been attributed to the benzylamino derivative acting as an H-bond donor to the serine-264 hydroxyl oxygen and strengthening the 264 -252 H -bond by conjugation. It is proposed that atrazine and other classical PS II inhibitors act in this way and that this may explain their ability to inhibit trypsin degradation of the D 1 peptide, if the 264-252 intramolecular H-bond plays an important role in stabilizing the peptide conform ation. It is also speculated that photodegradation may be related to the ability of QB
- to act as an H-bond acceptor and disrupt the 264-252 H-bond.
Binding of Triazines and Triazinones in the QB-Binding Niche of Photosystem II
Authors: Tietjen Klaus G. , Draber Wilfried , Goossens John , Jansen Johannes R. , Kluth Joachim F. , Schindler Michael , Wroblowsky Heinz-Jürgen , Hilp Ursula , Trebst Achim 
Published: August 2018

Abstract
A series of 20 triazines (derivatives of 2-alkylamino-4-benzylam ino-6-chloro-1,3,5-triazines) and 37 triazinones (derivatives of 3-alkyl-4-amino-6-phenyl-1,2,4-triazin-5-ones) is tested for inhibitory potency in photosynthetic electron flow through photosystem II of wild type Chlamydomonas reinhardtii and of five mutants with aminoacid substitutions in the D 1 protein at valine 219, alanine 251, phenylalanine 255, serine 264, and leucine 275. The data are used for computer modelling of the possible location of the compounds within a three dimensional model of the QB-binding niche of the D 1 protein.
The Role of D 1* in Light-Induced D 1 Protein Turnover in Leaves
Authors: Syme Anna J. , Bolhàr-N ordenkampf Harald R . , Critchley Christa 
Published: August 2018

Abstract
Light-induced degradation of the D 1 protein of photosystem II (PS II) was determined by radioactive pulse-chase labelling experiments in intact leaves of Schefflera polybotrya. PS II photochemical efficiency was monitored by measuring chlorophyll fluorescence. A significant and consistent decline in the Fv/ Fm ratio was taken to indicate photoinhibition. The formation and degradation of a modified form of the D 1 protein, D 1*, was different under photoinhibi-tory or non-photoinhibitory light conditions. At photoinhibitory irradiance greater amounts of D 1 * were formed relative to D 1, and the degradation of D 1* was slower when compared with non-photoinhibitory irradiance. The formation and degradation of D 1* were therefore shown to be at least partly light intensity dependent. Higher light intensities appeared to slow D 1* degradation, which suggests a modification in PS II turnover properties.
Kinetics of Electron Transfer between QA and QB in Wild Type and Herbicide-Resistant Mutants of Chlamydomonas reinhardtii
Authors: Crofts Antony R . , Baroli Irene , Kramer David , Taoka Shinichi 
Published: August 2018

Abstract
We have investigated the electron transfer kinetics for reduction of plastoquinone by photo­ system II in six mutant strains of Chlamydomonas reinhardtii by following the decay of the high fluorescence state after flash activation, and compared the separate reactions of the two-electron gate with those of a wild type strain. By analysis of the electron transfer kinetics, and separate measurement of the equilibrium constant for stabilization of the bound semiquinone after one flash, we have been able to deconvolute the contributions of rate constants and equilibrium constants for plastoquinone binding and electron transfer to the overall process. Two mutations, S 264 A and A 251 V, led to a marked slowing of kinetics for reduction of plastoquinone to the bound semiquinone. In S 264 A , the second electron transfer was also slower, but was normal in A 251 V. In mutant G 256 D , the electron transfer kinetics were normal after the first flash, but slowed after the second. In mutants L 257 F , V 219 I, and F 255 Y , the electron transfer kinetics after both flashes were similar to those in wild type. We discuss the results in terms of a model which provides a description of the mechanism of the two-electron gate in terms of measured kinetic and equilibrium constants, and we give values for these parameters in all strains tested.
Comparison of Photosynthetic Activities in Triazine-Resistant and Susceptible Biotypes of Chenopodium album
Authors: Curwiel Victor B. , Schansker Gert , de Vos Oscar J. , Rensen Jack J. S. 
Published: August 2018

Abstract
Triazine-resistant and susceptible Chenopodium album plants were grown at low and at high light irradiances. At the lower light irradiance the dry matter production of the resistant and the susceptible plants were almost similar. At the higher irradiance the resistant biotype had a significantly lower production. Fluorescence studies showed that the photochemical yield and the photosystem II electron transport rate were lower in the resistant biotype. It could be demonstrated in intact leaves that the lower productivity of the resistant biotype is caused by a higher sensitivity to photoinhibition. However, when studying effects of photoinhibition on electron flow and photophosphorylation in isolated thylakoids of the two biotypes, no significant differences between resistant and susceptible plant materials were observed. It is suggest­ ed that the difference between resistant and susceptible biotypes connected with processes protective against photoinhibition in intact leaves, are lost during the isolation of thylakoids.
Synthesis and Bleaching Activity of 1-Ethyl-and 1 -Propy 1-5-Substituted Imidazoles
Authors: Yamada Naotaka , Kuwano Eiichi , Eto  
Published: August 2018

Abstract
Twenty-eight 1-ethyl-and 1-propyl-5 -substituted imidazoles were synthesized an d their bleaching activity was evaluated by using the lettuce seedling test. 5-Phenyl-1-propylim idazole (1) caused distinct chlorosis, while none of the c ompounds with various alkenyl groups at the 5-position o the imidazole ring show ed this bleaching activity. Introduction of a bromo, chloro, fluoro, methyl or trifluoromethyl groupa t the 4-position on the benzene ring of com­pound 1 increased the activity in comparison with that of compound 1. 5-[4-(3-Chlorobenzyl-oxy)phenyl]-l-ethylimidazole (15) an d l-ethyl-5-[4-(3-methylbenzyloxy)phenyl]imidazole (21), analogs with a large substituent at the 4 -position on the benzene ring, also caused pronounced chlorosis in the lettuce seedlings. Both compounds 1 and 15 a t 30 ppm decreased total c arot­enoid content in the lettuce seedlings to less than 40% of that in the control, and the reduction of total carotenoid content correlated well with treatment dose.
On the Occurrence of Caffeoyltartronic Acid and Other Phenolics in Chondrilla juncea
Authors: Terencio M. C. , Giner R. M. , Sanz M. J. , Máñez S. , Ríos J. L. 
Published: August 2018

Abstract
Caffeoyltartronic acid and other eleven phenolic com pounds were identified in the MeOH extract of Chondrilla juncea: the flavonoids luteolin, luteolin-7-glucoside, luteolin-7-galactosylglucuronide and quercetin-3-galactoside; the phenolic acids protocatechuic, caffeic, chlorogenic, isochlorogenic and isoferulic and the coumarins cichoriin and aesculetin. The taxonomic im plications of these com pounds have been discussed.
The Biflavonoid Pattern of Anacolia webbii
Authors: Seeger Tassilo , Geiger Hans , Mues Rüdiger , Zinsmeister Hans Dietmar 
Published: August 2018

Abstract
From Anacolia webbii the following five biflavonoids could be isolated: 2,3-dihydrophilonotisflavone, philonotisflavone, dicranolomin, 5′,3‴-dihydroxyamentoflavone and 5′,3‴-dihydroxyrobustaflavone. The compounds were identified spectroscopically.
Phellodonic Acid, a New Biologically Active Hirsutane Derivative from Phellodon melaleucus (Thelephoraceae, Basidiomycetes) [1]
Authors: Stadler Marc , Anke Timm , Dasenbrock Johannes , Steglich Wolfgang 
Published: August 2018

Abstract
A new hirsutane derivative, phellodonic acid (1), has been isolated from fermentations of Phellodon melaleucus strain 87113. Its structure was elucidated by spectroscopic methods. The compound exhibits antibiotic activities towards bacteria and fungi. 1 is the first bioactive metabolite from cultures of a species belonging to the family Thelephoraceae.
Genetic Engineering of Disease and Pest Resistance in Plants: Present State of the Art
Authors: Strittmatter Günter , Wegener Dorothee 
Published: August 2018

Abstract
Rapid progress in gene technology has allowed, on the one hand, insight to be gained into the complex molecular mechanisms of plant/pathogen recognition and the natural defence strategies of host plants. On the other hand, this technology can also be used for the controlled and efficient generation of genetic variability and for the identification of desirable genotypes, far beyond the possibilities of classical breeding. The first successful attempts have been made to improve resistance against pathogenic viruses, bacteria, fungi and insects by engineering transgenic plants. The majority of these strategies were based on constitutively expressing single proteins that are either toxic to the pathogen/pest, or interfere with its reproductive cycle. More refined strategies, which are at the stage of testing, try to mimic and modify naturally-evolved defence reactions of plants and, thereby, will potentially confer a more durable resistance to a broad range of pathogens
Comparative FTIR and 13C CP/MAS NMR Spectroscopic Investigations on Sporopollenin of Different Systematic Origins
Authors: Wilmesmeier Sabine , Steuernagel Stefan , Wiermann Rolf 
Published: August 2018

Abstract
Comparative phytochemical investigations were carried out on sporopollenins of the follow­ ing plant species: Bryophyta -Reboulia hemisphaerica and Polytrichum strictum; Pteridophyta -Equisetum arvense, Selaginella selaginoides micro-and megaspores; Gymnospermae -Cycas circinalis; Angiospermae -Typha angustifolia and Tulipa cv. “Apeldoorn”. Although the range of the analyses included species from the Bryophyta to the Angiospermae, fundamen tal correspondences could be detected in the 13C NMR and FTIR spectra concerning the occur­rence of aliphatics, aromatics, ether and carbonyl/carboxylic functions in varying degrees. While the amount of aliphatics strongly dominated in the molecular structure of all other sporopollenins investigated here, it was found in sporopollenin of Equisetum arvense in a much lower extent. Despite the different morphology of Selaginella selaginoides micro-and mega­ spores, their sporopollenin spectra were nearly identical
Naturally Occurring Antidotes against Benzimidazole Fungicides
Authors: Tahara Satoshi , Matsukura Yumiko , Katsuta Hiroyuki , Mizutani Junya 
Published: August 2018

Abstract
TLC bioautography using precoated glass thin-layer plates impregnated with benomyl or carbendazim (MBC), and Cladosporium herbarum as a test fungus was evaluated as a facil way to detect plant secondary metabolites antidoting against benzimidazole fungicides. In addition to emodin and a-tocopherol from Polygonum sachalinense, three phenolics, 3,5-dihydroxy- 4-methylstilbene and 5-methoxy-6,7-methylenedioxyflavone from P. lapathifolium, and 2,6-dim ethoxybenzoquinone from P. thunbergii were isolated and characterized as new benzimidazole antidotes. Emodin exhibited the antidoting activity not only against benomyl but also against carbendazim (M BC), thiabendazole (TBZ), thiophanate-methyl and nocodazole. Furthermore, emodin showed antidoting activity against MBC in the wild-type Neurospora crassa and against diethofencarb in the mutant of N. crassa resistant to benzimidazole fungicides but highly susceptible to diethofencarb
Phytoalexine mit Indolstruktur aus Kohlrabi {Brassica oleracea var. gongylodes)+ / Indole Phytoalexins from the Kohlrabi (Brassica oleracea var. gongylodes)+
Authors: Gross Dieter , Porzel Andrea , Schmidt Jürgen 
Published: August 2018

Abstract
UV-irradiation of sliced stem tubers of kohlrabi (Brassica oleracea var. gongylodes) followed by incubation for 4 days, resulted in the production of two new sulphur-containing indole phytoalexins, cyclobrassinone and 1 -methoxyspirobrassinin, whose structures were elucidated on the basis of spectroscopic data. Three known indole phytoalexins, spirobrassinin, methoxybrassitin and methoxybrassinin, and several m inor phytoalexin-like compounds not yet identified were also isolated. The accumulation of these indole phytoalexins was also induced by abiotic elicitation with CuCl2.
Feeding both of L-[β-14C]tryptophan and L-[14CH3]methionine to UV-irradiated stem tuber tissue of kohlrabi indicated that the S-containing indole phytoalexins were biosynthesized from these amino acids.
Immunological Evidence for the Binding of β-Carotene and Xanthophylls onto Peptides of Photosystem I from Nicotiana tabacum
Authors: Makewicz A. , Radunz A. , Schmid G. H. 
Published: August 2018

Photosystem I preparations were obtained from wild type tobacco Nicotiana tabacum var. John William’s Broadleaf (JWB) and from the two chlorophyll-deficient mutants N. tabacum Su/su and N. tabacum Su/su var. Aurea. The preparations were characterized with respect to the chlorophyll a/b ratio, their photosynthetic activity and their absorption spectroscopic properties. Peptides from these preparations were analyzed by SDS polyacrylamide gel electrophoresis and transferred for the detection of bound carotenoids according to the Western blot procedure to nitrocellulose or Immobilon membranes. The PS I preparation from the wild type JWB consisted of the core and the LHCP complex. The core complex contains the two core peptides with the same apparent MW of 66 kDa and several peptides with the lesser molecular masses of 22, 20, 19, 17, 16, 10 and 9 kDa. The light-harvesting protein complex consists of 4 subunits with the molecular masses 28, 26, 25 and 24 kDa. The PS I preparations of the yellow-green mutant Su/su and of the Aurea mutant Su/su var. Aurea contain as impurity traces of the D1 and D2 core peptides of photosystem II and also traces of the chlorophyll-binding photosystem II peptides with the molecular masses 42 and 47 kDa.
The peptides of the photosystem I preparation were characterized by specific photosystem I antisera: An antiserum to the photosystem I complex reacts in the Western blot only with the homologous peptides of photosystem I. In comparative analyses with photosystem II preparations this antiserum (directed to photosystem I) reacts, as expected, only with the peptides of the light-harvesting complex. An antiserum to the CP 1 core peptides reacts only with the 66 kDa peptides of photosystem I and gives no cross reaction with heterodimer forms of the D1/D2 core peptides of photosystem II.
In the Western blot procedure by means of polyclonal monospecific antisera to carotenoids it was demonstrated that β-carotene is bound in high concentration onto the core peptides CP 1 and to a lesser extent onto the two larger subunits of the LHCP complex, exhibiting the molecular masses of 28 and 26 kDa. Neoxanthin is bound onto the same peptides. In contrast to this, lutein was only identified on the core peptides CP 1 and violaxanthin only on the larger subunits of the LHCP complex. As the carotenoids are labelled with antibodies, even after SDS treatment in the electrophoresis, it is assumed, that the carotenoids are covalently bound via the ionon ring to the respective peptide
Binuclear Manganese(III) Complexes as Electron Donors in D1/D2/Cytochrome b 559 Preparations Isolated from Spinach Photosystem II Membrane Fragments
Authors: Allakhverdiev S. I. , Karacan M. S. , Somer G. , Karacan N. , Khan E. M. , Rane S. Y. , Padhye S. , Klimov V. V. , Renger G. 
Published: August 2018

Abstract
The capability of different manganese complexes to act as PS II electron donors in D1/D2/ cytochrome b 559 complexes has been analyzed by measuring actinic light-induced absorption changes at 680 nm (650 nm) and 340 nm, reflecting the photoaccumulation of Pheophytin- (Pheo-) and the reduction of NADP+ respectively. The data obtained reveal: a) the donor capacity of synthetic binuclear Mn(III)2 complexes containing aromatic ligands significantly exceeds that for MnCl2 in both cases, i.e. Pheo- photoaccumulation and NADP+ reduction; b) manganese complexes can serve as suitable electron donors for light-induced NADP+ reduction catalyzed by D1/D2/cytochrome b559 complexes and ferredoxin plus ferredoxin- NADP+ reductase under anaerobic conditions and c) the specific turnover rate of the system leading to NADP+ reduction is extremely small.
The implications of these findings are briefly discussed.
Impact of UV-B Radiation on the Lipid and Fatty Acid Composition of Synchronized Ditylum brightwellii (West) Grunow
Authors: Döhler Günter , Biermann Thomas 
Published: August 2018

Abstract
The marine diatom Ditylum brightwellii (West) Grunow isolated from the Baltic Sea could be synchronized by a light/dark rhythm of 6.5:17.5 h (white light intensity 8 W m-2) at 18 °C and 0.035 vol.% CO2. Content of protein, DNA and RNA increased linearly up to the end of the cell cycle. Pigments (chlorophyll a, chlorophyll c1 + c2, carotenoids) and galactolipids were synthesized in the light period only. A lag phase of 2 h was observed in the biosynthesis of sulphoquinovosyl diacylglycerol and phosphatidylglycerol. Formation of phosphatidylglycerol and phosphatidylcholin continued in the dark period (30% and 28%, respectively). The pattern of major fatty acids (C14:0, C16:1, C16:0, C18:1 and C20:5) varied during the cell cycle of Ditylum.
Biosynthesis of acyl lipids was reduced in dependence on the UV-B dose. The most sensitive lipid was digalactosyl diacylglycerol (total inhibition at 585 J m-2), whereas phosphatidylcholin was less affected (20% reduction). UV-B radiation during the dark period had no effect on the lipid and pigment content. Strongest inhibitory effect of UV-B on cell division, synthesis of protein, pigments, sulphoquinovosyl diacylglycerol and phosphatidylglycerol was found after UV-B radiation at the beginning of the cell cycle (0.-2. h). An exposure time at the end of the light period (4.-6. h) led to a marked damage on the synthesis of monogalactosyl diacylglycerol and phosphatidylglycerol. These findings indicate a stage-dependent response of Ditylum to UV-B irradiance. The impact of UV-B resulted in an increase of unsaturated long chained fatty acids (C18, C20) and in a diminution of short chained fatty acids (C14, C16). Content of ATP was not affected by UV-B radiation under the used conditions. The inhibitory effect of UV-B on synthesis of DNA, RNA, protein and acyl lipids was mainly reversible. Results were discussed with reference to UV-B damage on the enzymes involved in the biosynthesis of acyl lipids and by a reduction of available metabolites.
Lipoxygenase Forms Located at the Plant Plasma Membrane
Authors: Nellen Arndt , Rojahn Barbara , Kindl Helmut 
Published: August 2018

Abstract
In cucumber cotyledons (Cucumis sativus L.) containing several soluble and particulate forms of lipoxygenase (LOX), the location of LOX forms in microsomes has been studied. We concentrated on the question whether the plasma membrane contains one or more forms of LOX. As methodology, we applied both the two-phase partition with polyethylene glycol/dextran and density gradient flotation of plasma membrane-enriched membrane fractions. Both methods show that a high percentage of the microsomal LOX can be attributed to the plasma membrane. Emphasis was put on the findings that the LOX located at the plasma membrane consisted of a species behaving as an integral membrane protein and another form characterized as a peripheral membrane protein by solubilization with carbonate. With long distance SDS-PAGE and immunodecoration using anti-lipid body LOX antiserum, it is possible to distinguish between microsomal LOX forms by small but significant differences in size. Treatment of seedlings with methyl jasmonate led to an enhanced level of LOX at the plasma membrane.
Polyols that Accumulate in Renal Tissue Uncouple the Plasma Membrane Calcium Pump and Counteract the Inhibition by Urea and Guanidine Hydrochloride
Authors: Sola-Penna Mauro , Lemos Adriana dos Passos , Fávero-Retto Maely P. , Meyer-Fernandes José Roberto , Vieyra Adalberto 
Published: August 2018

Abstract
Sorbitol and mannitol, two stereoisomeric osmolytes, inhibit the ATP-dependent Ca2+ transport in inside-out vesicles derived from basolateral membranes from kidney proximal tubules. This inhibition (I0,5 = 400 and 390 mᴍ respectively) cannot be attributed to an in­ crease in Ca2+ permeability, since the rate of EGTA-stimulated Ca2+ efflux from preloaded vesicles is not modified by these osmolytes. In the presence of 1 ᴍ sorbitol or mannitol, Ca2+ uptake is inhibited by 70 and 75%, respectively. Since the Ca2+-stimulated ATPase activity is unaffected, sorbitol and mannitol uncouple the Ca2+ transport from the ATPase activity. The inhibition of Ca2+ transport by these osmolytes is reversible, since the inhibition dis­appears when the vesicles are preincubated with 1 ᴍ sorbitol or mannitol and then diluted 25-fold in reaction medium to measure Ca2+ accumulation. On the other hand, these osmo­lytes protect the (Ca2+ +Mg2+)ATPase from the inhibition of Ca2+ transport and ATPase activity by urea and guanidinium. These data suggest that the high concentrations of polyols that renal cells accumulate during antidiuresis, may regulate Ca2+ transport across the plasma membrane. In addition, polyols may protect the (Ca2+ + Mg2+) ATPase from the deleterious structural effects of urea, a compound that also accumulates during antidiuresis.