bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flavonoids from Some Frullania Species (Hepaticae)
Authors: Kraut L. , Scherer B. , Mues R. , Sim-Sim M. 
Published: August 2018

Abstract
From Frullania teneriffae 5 known flavone aglycones and 6 flavone glycosides were isolated, among them the new 6-OH-luteolin-6-O-β-ᴅ-glucoside-7-O-β-ᴅ-glucoside-6′′′-(3-hydroxy-3-methylglutaroylester). F. cesatiana contains 2 flavone-di-C-glucosides and the new 6-OH-luteolin-7-O-β-ᴅ-glucoside-6′′-(3-hydroxy-3-methylglutaroylester)-3′-O-glucuronide.
The phenolic pattern of F. eboracensis was compared to that of F. muscicola. The known 6-OH-luteolin-7-O-β-ᴅ-glucoside-6′′-(3-hydroxy-3-methylglutaroylester) was identified from F. gibbosa and F. arecae.
Partially N-Deacetylated Chitin Oligomers (Pentamer to Heptamer) are Potential Elicitors for (+)-Pisatin Induction in Pea Epicotyls
Authors: Akiyama Kohki , Kawazu Kazuyoshi , Kobayashi Akio 
Published: August 2018

Abstract
Oligomers (dimer to heptamer) of chitosan and their partially/completely N-acetylated derivatives were examined for (+)-pisatin-inducing activities in pea epicotyl elicitor assay at concentrations ranging from 6.25 to 100 μg/ml. The structures of the oligomers were analyzed by 1H NMR and MALDI TOF MS spectrometers. The chitosan oligomers from dimer to tetramer were inactive, while the pentamer exhibited a moderate activity at 100 μg/ml. The hexamer showed a pronounced activity at 100 μg/ml, whereas the oligomer had no activity at the higher concentrations. Although the chitosan heptamer induced a moderate amount of (+)-pisatin (ca. 60 μg/g fr. wt.) at 50 μg/ml, the oligomer did not elicit pisatin formation at 100 μg/ml. The dimer to tetramer of both partially N-deacetylated chitin (DAC) and chitin were totally inactive. The DAC pentamers (d.a. 31%, 52%), DAC hexamers (d.a. 26%, 41%), and DAC heptamers (d.a. 26%, 36%) exhibited significant elicitor activities at lower concentrations (6.25-25 μg/ml) than the native chitosan oligomers. The chitin pentamer to heptamer had weak or no activity. Both glucosamine and N-acetylglucosamine were inactive in the assay. These facts suggest that the DAC pentamer to heptamer may act as elicitors for pisatin induction in pea-fungus interactions.
Semiochemicals of the Scarabaeinae, V*: Characterization of the Defensive Secretion of the Dung Beetle Oniticellus egregius
Authors: Burger B. V. , Petersen W. G. B. , Tribe G. D. 
Published: August 2018

Abstract
Using techniques that were developed for the concentration and analysis of airborne or­ganic volatiles, methyl salicylate and 1,4-benzoquinone were found to be the only two com ­ pounds present in detectable quantities in the effluvium of Oniticellus egregius. These two compounds, previously identified in the defensive secretions of other arthropods, are pre­sumed to be produced as a defense mechanism against predators, such as birds. Methyl salicylate and 1,4-benzoquinone have thus far not been found to occur in other Scarabaeinae.
The Response of Rat Serum Lipids to Diets of Varying Composition or Contaminated with Organochlorine Pesticides
Authors: Boll Meinrad , Weber Lutz W. D. , Stampfl Andreas 
Published: August 2018

Abstract
The effects of different diets (high carbohydrate, high protein, high fat) and diets contaminated with polychlorinated biphenyls (PCBs) and/or γ-hexachlorocyclohexane (lindane) on the levels of serum triglycerides, cholesterol and phospholipids were investigated in Wistar rats. Serum triglyceride levels differed significantly among the diets, while those of cholesterol and phospholipids were much less affected by the diet composition. A change in diet composition resulted in a gradual adaptation to the lipid levels characteristic of the new diet with major variations including oscillations. There was, however, no specific component of a diet that could be associated with any specific change in serum lipids. While feed deprivation decreased the serum lipids (40-65% in 3 days), refeeding the starved animals caused pronounced increases of the lipids that were different among the diets. The response of the triglyceride levels was the strongest (up to 10 times the starvation levels) followed by those of the phospholipids (4-fold) and cholesterol (2.5-fold). Response of the triglyceride levels peaked within 1 or 2 days of refeeding, whereas those of cholesterol and phospholipids took 4 days to reach the maximum. Feeding PCB-contaminated diets increased the serum lipids in a dose-dependent manner (15-250 ppm). Higher PCB concentrations were increasingly inhibitory (350 ppm) or overtly toxic (> 400 ppm). Elevated lipids returned to the starting levels immediately after peaking (triglycerides) or only after several days (cholesterol, phospholipids) but with an earlier onset at lower PCB concentrations. Refeeding starved animals with PCB- contaminated diets also increased the serum lipids dose-dependently. Feeding lindane-containing diets (50-150 ppm) as well as refeeding animals with lindane diets resulted in a considerable increase of the triglyceride levels, while cholesterol and phospohlipids increased much less. Higher lindane concentrations ( 250 ppm) were inhibitory. The outcome on serum lipid levels on feeding diets contaminated with both PCBs and lindane was basically additive.
Enzymatischer Abbau der Embryonalhüllen des Lanzettfischchens, Branchiostoma lanceolatum, während des Schlüpfens / Hatching through Enzymatic Breakdown of the Embryonic Coats in the Lancelet, Branchiostoma lanceolatum (Cephalochordata)
Authors: Denucé J. Manuel 
Published: August 2018

Abstract
A study was made of the hatching process of the lancelet, Branchiostoma lanceolatum (Amphioxus), under laboratory conditions. Embryos in the early neurula stage (5 to 6 pairs of somites) escape through a hole made in the fertilization envelope, following intensive rotatory movements and partial digestion of the envelope. Using the chromogenic substrate Hide Powder Azure (HPA) at pH 8.0, proteolytic activity was detected in the hatching medium. The effect of various protease inhibitors was investigated. Whereas the activity was only slightly affected by inhibitors of trypsin, chymotrypsin or thiol proteases, chelating agents such as EDTA and 1,10-phenanthroline prevented the degradation of HPA, as well as the breakdown of the vitelline membrane of alcohol fixed oocytes by the protease from hatching fluid. These data suggest the presence of a metalloprotease in the hatching medium. How far this enzyme can be compared with hatching enzymes found in echinoderms and fishes (where they have been identified as matrix degrading metalloproteases), awaits further study of the lancelet enzyme, including its isolation and purification.
Nutritional Regulation of the Activities of Lipogenic Enzymes of Rat Liver and Brown Adipose Tissue
Authors: Boll Meinrad , Weber Lutz W. D , Stampfl Andreas 
Published: August 2018

Abstract
Nutrition-induced effects on the activity of enzymes of lipogenesis, fatty acid synthase (FAS; EC 2.3.1.85). ATP citrate lyase (ACL; EC 4.1.3.8), malic enzyme (ME; EC 1.1.1.40), glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) and 6-phosphogluconate dehy­ drogenase (PGDH; EC 1.1.1.44) were investigated in liver and interscapular brown adipose tissue (BAT) of rats. The lipogenic enzymes could be grouped into two categories according to their response to dietary manipulations; FAS and ACL. both key enzymes of lipogenesis, responded fast and strongly to dietary manipulations. ME, G6PDH and PDGH, enzymes which also contribute to metabolic pathways other than lipogenesis, responded in a more sustained and less pronounced fashion. Feed deprivation caused the specific activities of lipogenic enzymes to decline several-fold. Refeeding of previously fasted (up to 3 days) animals increased the activities dramatically (10-to 25-fold) to far above pre-fasting levels (“overshoot”). Repetition of the fasting/refeeding regimen increasingly impaired the ability of both tissues to synthesize overshooting enzyme activities in the subsequent refeeding period. The fasting-induced decline of the activities was prevented when sugars were provided to the animals via drinking water. The sugars displayed different effectivities; sucrose= glucose> fructose> maltose » lactose. Sugars as the sole nutrient after fasting were also able to induce overshooting enzyme activities. Again, activities of FAS and ACL responded in a more pronounced fashion than the other three enzymes. Transition from feeding one diet to feeding a new diet of different composition led to adaptation of the lipogenic enzyme activities to levels characteristic for the new diet. Replacing a low-carbohydrate with a high-carbohydrate diet proceeded with major alterations of enzyme activities. This process of attaining a new level took up to 20 days and involved pronounced oscillations of the specific activities. In contrast, when a high-carbohydrate diet was replaced with another diet, particular one high in fat, transition to new enzyme activities was completed within 2 -3 days and proceeded without oscillations. All dietary manipulations caused more pronounced responses in young (35d-old) than in adult (180d-old) animals.
Accumulation of Protoporphyrinogen IX Induced by Acifluorfen Methyl
Authors: Sumida Motoo , Niwata Shinjiro , Tanaka Takaharu , Furuno Tadahide , Nakanishi Mamoru , Wakabayashi Ko , Böger Peter 
Published: August 2018

Abstract
Confocal fluorescence microscopic images were used to investigate the accumulation site of protoporphyrin IX (PPIX) within liverwort cells (Marchantia polymorpha L.) treated with peroxidizing herbicides as acifluorfen methyl (AFM). A high level of PPIX accumulation was observed in the cells during 12 h to 24 h after the addition of AFM . The results obtained from confocal fluorescence microscopic images gave clear evidence that the accumulation of PPIX occurred only in the chloroplasts, but was not observed in the cytosol or at the plasma membrane. The presence of PPIX in the chloroplasts strongly suggests that protoporphyrino­ gen (Protogen) accumulates by inhibition of protoporphyrinogen oxidase (Protox) which is the target enzyme for peroxidizing herbicides. The plastidic occurrence of PPIX provides evidence of either the presence of an additional herbicide-resistant Protox or of a non-enzy-matic Protogen-oxidation system in the Marchantia chloroplast.
Copper Ion Inhibition of Electron Transport Activity in Sodium Chloride Washed Photosystem II Particle Is Partially Prevented by Calcium Ion
Authors: Sabat Surendra Chandra 
Published: August 2018

Abstract
The inhibitory effects of copper ion (Cu2+) on the photosynthetic electron transport func­tion was investigated both in NaCl washed (depleted in 17 and 23 kDa polypeptides) and native (unwashed) photosystem II membrane preparations from spinach (Beta vulgaris) chlo-roplasts. Copper in the range of 2.0 to 15 μᴍ strongly inhibited the electron flow from water to 2,6-dichlorobenzoquinone in NaCl washed particles in a concentration dependent manner. Com plete inhibition was noticed at 15 μᴍ Cu2+. Oppositely in native membranes, 15 μᴍ C u2+ inhibited only 10-12% of control activity. It was found that calcium ion (Ca2+) significantly reduced the Cu2+ inhibition of electron transport activity. The Ca2+ supported prevention of Cu2+ toxicity was specific to Ca2+. Further analysis indicated that both Cu2+ and Ca2+ act competitively. Since Ca2+ is known to have stimulating/stabilizing effect at the donor side of photosystem II, it is therefore suggested that Cu2+ in NaCl washed particles exerts its inhibi­tory effect(s) at the oxidizing side of photosystem stimulates/stabilizes the oxygen evolution.
The Catalytic Mechanism of Tyrosine Phenol-Lyase from Erwinia herbicola: The Effect of Substrate Structure on pH-Dependence of Kinetic Parameters in the Reactions with Ring-Substituted Tyrosines
Authors: Faleev N. G. , Spirina S.N. , Ivoilov V. S. , Demidkina T. V. , Phillips R. S. 
Published: August 2018

Abstract
Apparently homogeneous tyrosine phenol-lyase (TPL) from Erwinia herbicola has been prepared by a new method. The pH-dependencies of the main kinetic parameters for the reactions of Erwinia TPL with tyrosine, 2-fluorotyrosine, 3-fluorotyrosine, 2-chlorotyrosine, and 3.4-dihydroxyphenylalanine (DOPA ) have been studied. The pattern of pH-dependence of Vmax depends on the nature of the substituent in the aromatic ring. For the substrates bearing small substituents (H, 2-F, 3-F) Kmax values were found to be pH-independent. For 2-chlorotyrosine and DOPA Vmax decreased at lower pH, the effect being described by equation with one pKa. Generally two bases are reflected in the pH dependence of Vmax/Km. The first base, probably is responsible for the abstraction of a-proton, while the second one, interacts with the phenolic hydroxyl at the stage of binding. The reaction of TPL with DOPA differs from the reactions with other tyrosines by the requirement of an additional base which is reflected in the pH-profiles of both and Vmax/Km. For the reaction of TPL from Citrobacter intermedins with DOPA only Vmax/Km values could be determined. The activity of Citrobacter enzyme towards DOPA is considerably less than that of E. herbicola enzyme, and its maximal value is attained at higher pH.
(+)-10α-Hydroxy-4-muurolen-3-one, a New Inhibitor of Leukotriene Biosynthesis from a Favolaschia Species. Comparison with Other Sesquiterpenes
Authors: Zapf Sylvia , Wunder Annette , Anke Timm , Klostermeyer Dörte , Steglich Wolfgang , Shan Rudong , Sterner Olov , Scheuer Werner 
Published: August 2018

Abstract
A new inhibitor of leukotriene biosynthesis, (+)-10α-hydroxy-4-muurolen-3-one (1), was isolated from fermentations of Favolaschia sp. 87129. Its structure was established by spectroscopic methods. The compound exhibited no antifungal or antibacterial activities.
The effects of 1 on leukotriene biosynthesis were compared with (+)-T-cadinol, (-)-3-oxo-T-cadinol, and (+)-3a-hydroxy-T-cadinol, three related sesquiterpenes.
Lactarane Type Sesquiterpenoids as Inhibitors of Leukotriene Biosynthesis and Other, New Metabolites from Submerged Cultures of Lentinellus cochleatus (Pers. ex Fr.) Karst
Authors: Wunder Annette , Anke Timm , Klostermeyer Dörte , Steglich Wolfgang 
Published: August 2018

Abstract
Three known sesquiterpenoids of the lactarane and secolactarane type, deoxylactarorufin A (1), blennin A (2) and blennin C (3), have been obtained from cultures of Lentinellus cochleatus (Basidiomycetes) together with the new metabolites (Z)-2-chloro-3-(4-me-thoxyphenyl)-2-propen-l-ol (4) and lentinellone (5), a protoilludane derivative. The structures were determined by spectroscopic investigations. 1, 2 and 3 are potent inhibitors of leukotriene biosynthesis in rat basophilic leukemia (RBL-1) cells and human peripheral blood leukocytes (PBL).
Antiviral Activity of Some Hydroxycoumarin Derivatives
Authors: Galabov Angel S. , Iosifova Tanya , Vassileva Elka , Kostova Ivanka 
Published: August 2018

Abstract
Esculetin (6,7-dihydroxycoumarin) and its diacetate exhibited a marked inhibitory effect on Newcastle disease virus replication in cell cultures at concentrations of 36 jam and 62 jam, respectively. These compounds were selected from ten hydroxycoumarin derivatives through an in vitro antiviral screen involving viruses of the picorna-, orthomyxo-, paramyxo-, and herpes virus families.
Is Isoprene Emitted by Plants Synthesized via the Novel Isopentenyl Pyrophosphate Pathway?
Authors: Zeidler Johannes G. , Lichtenthaler Hartmut K. , May H. Ulrich , Lichtenthaler Frieder W. 
Published: August 2018

Abstract
The incorporation of deuterium labeled 1-deoxy-ᴅ-xylulose into isoprene, emitted by three higher plants upon illumination, was analysed by headspace GC-MS. A high extent of incorporation into isoprene was found, indicating that isoprene is synthesized in higher plants via the novel isopentenyl pyrophosphate pathway, of which 1-deoxy-ᴅ-xylulose-5-phosphate is an intermediate. A new chemical synthesis of methyl [ 1-2H1]-1-deoxy-α/β-ᴅ-xyluloside from ᴅ-xylulose is presented.
On the Requirement of Bound Bicarbonate for Photosystem II Activity
Authors: Govindjee  , Xu C. , van Rensen J. J. S. 
Published: August 2018

Abstract
In photosystem II of plants and cyanobacteria, but not in reaction centers of anoxygenic photosynthetic bacteria, formate is known to inhibit electron flow which is reversed fully upon bicarbonate addition. At issue has been an old controversy whether this effect is on the acceptor or the donor side of photosystem II (PS II). We present here data on chloroplast thylakoids for donor side effects, that is accompanied by acceptor side effects, from measurements on chlorophyll a fluorescence yield changes after light flashes 1-6. Further, sensitive differential infrared gas analyser measurements show that bicarbonate is indeed bound in both maize and pea thylakoid suspensions depleted of CO2 without any inhibitor; here, high rates of electron flow are associated with the presence of a maximum of 0.8 to 1.25 (corrected for residual activity) CO2 per photosystem II reaction center. It is suggested that bicarbonate bound to the acceptor side is required for photosystem II activity , both on the acceptor and the donor sides in the same experiment and in the same sample.
Plural Origins of Molecular Homochirality in Our Biota Part II. The Relative Stabilities of Homochiral and Mixed Oligoribotides and Peptides
Authors: Soares Thereza Amélia , Lins Roberto Dias , Longo Ricardo , Garratt Richard , Ferreira Ricardo 
Published: August 2018

Abstract
By computer simulations -molecular mechanics and molecular dynamics with the amber force field (Weiner et al., (1986), J. Comp. Chem. 7, 2 30-252) -we have determined the stabilities of oligoribotide strands built with ᴅ -and ʟ-riboses, and of peptide chains with ᴅ -and ʟ-amino acid residues. In particular, complementary double-chains of oligoribotides were studied, since they are an important feature of the growing mechanism of modern nucleic acids. Peptide chains on the other hand, grow without need of a template. We found that mixed oligoribotides are less stable than homochiral ones, and that this chiral effect is less noticeable in peptide chains. The results support the interpretation that ʟ-riboses act as terminators to the template-assisted growth of oligo-r-Gᴅ (enantiomeric cross-inhibition; Joyce et al., (1987), Proc. Natl. Acad. Sci. USA 84, 4398-4402). Based on this effect, a chemical pathway is proposed which could, under assumed prebiotic conditions, bypass the hindrance of homochiral growth.
Quinolizidine Alkaloids of Platycelphium vöense (Engl.) Wild (Leguminosae)
Authors: Asres Kaleab , Tei Andreas , Wink Michael 
Published: August 2018

Abstract
13 Alkaloids were identified in leaves and twigs of Platycelphium vöense (a monotypic genus in the tribe Sophoreae) by capillary GLC and GLC-MS. Cytisine, N-methylcytisine, anagyrine and 5,6-dehydrolupanine figured as major and N-formylcytisine, N-acetylcytisine, baptifoline, thermopsine, isolupanine, and rhombifoline as minor alkaloids in both leaves and twigs. Lupanine occurred in considerable amount in the leaves and as a minor component in the twigs. The rare alkaloid, 6β-hydroxylupanine, was detected only in the leaves while N-ethylcytisine was shown to be a minor constituent of the twigs only.
Purification and Characterization of Cytochrome c6 from the Unicellular Green Alga Scenedesmus obliquus
Authors: Wünschiers Röbbe , Zinn Thomas , Linder Dietmar , Schulz Rüdiger 
Published: August 2018

Abstract
Purification of a soluble cytochrome c6 from the unicellular green alga Scenedesmus obliquus by a simple and rapid method is described. The purification procedure includes ammonium sulfate precipitation and non-denaturating PAGE. The N-terminal sequence of the first 20 amino acids was determined and shows 85% similarity and 75% identity to the sequence of cytochrome c6 from the green alga Monoraphidium braunii. The ferrocyto-chrome shows typical UV/VIS absorption peaks at 552.9, 521.9 and 415.7 nm. The apparent molecular mass was estimated to be 12 kD a by SDS-PAGE. EPR-spectroscopy at 20K shows resonances indicative for two distinct low-spin heme forms.
How Tree Roots Gather Oxygen from Soil for Energy Supply by Respiration
Authors: Frick Hans-Joachim , Woermann Dietrich , Grosse Wolfgang 
Published: August 2018

Abstract
The gas exchange between the root system of the European alder (Alnus glutinosa (L.) Gaertn.) and the surrounding soil is studied using four-year-old trees. For the experiments the root system connected to its stump is exposed to gases of different molar mass. The stump is cut above the soil surface and in contact with the external atmosphere. A net convective volume flow of gas from the soil into the roots and out of the stump is observed if the mean molar mass of the gas present in the soil is lower than that present in the intercellular space of the roots. The direction of the convective gas flow can be reversed by increasing the molar mass of the gas present in the soil. These phenomena are governed by Graham 's law of diffusion. They demonstrate the importance of gas convection for the gas exchange in tree roots.
Fluorescence of Chromatin DNA Induced by Antitumoral Naphthalimides
Authors: Stockert J. C. , Cañete M. , Villanueva A. , Juarranz A. , Trigoso C. I. , Braña M. F. 
Published: August 2018

Abstract
Treatment of chicken blood smears and semithin sec­tions from Epon-embedded mouse tissues with aqueous solutions of the 3-aminonaphthalimides FA-142, FA-2043, and FA-2143 induced a strong green-yellow fluorescence of chromatin under violet or violet-blue excitation. Chromatin emission was abolished by previous DNase or hot TCA treatment. The use of 3-methoxy (FA-655) and 3-nitro derivatives (M-4212 and M-12210) resulted in very weak fluorescence of chromatin. Ab­sorption maxima at 346 and 408 nm and an emission peak at 570 nm were observed for the free compound FA-142. Fluorescence properties open new and interesting applications for some of these antitumoral and DNA-intercalating naphthalimides.
Intra-and Interspecific Allelochemical Effects in Three Kalanchoe-Species (Crassulaceae)
Authors: Bär W. , Pfeifer P. , Dettner K. 
Published: August 2018

Abstract
The intra-and interspecific acting allelochemicals of Kalanchoe daigremontiana, K. tubiflora and K. pinnata (Crassulaceae) were isolated and could be identified as p-hydroxybenzoic-, protocatechuic-, gallic-, p-coumaric-and coffeic acid. By measuring length of stems and primary roots of Kalanchoe-daughter plants the intra-and interspecific inhibitory activities of authentic compounds could be demonstrated.