bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Subcomplex Organization of the Major Chlorophyll a/b-Protein Light- Harvesting Complex of Photosystem II (LHCII) in Barley Thylakoid Membrane
Authors: Jackowski Grzegorz 
Published: August 2018

Abstract
The major chlorophyll a/b-protein light-harvesting complex of photosystem II (LHCII) isolated form barley photosynthetic membrane was shown to contain five major polypeptides only two of which (26.7 and 25.6 kDa) were found to be its true constituents as judged by the ability to migrate as oligomers in various analytical systems. When analyzed by a vertical-bed non-denaturing isoelectric focusing the LHCII was resolved into five trimeric subcom­plexes (designated 1 -5 in order of decreasing p I) containing either only 26.7 kDa polypeptide (subcomplexes 1 and 2) or 26.7 and 25.6 kDa ones associated at 2:1 ratio (subcomplexes 3 -5) . The polypeptide of 26.7 kDa could be split by denaturing isoelectric focusing into fifteen molecular forms while nine molecular species were found to be constituents of 25.6 kDa polypeptide. The subcomplexes 1 -5 contained molecular forms of one or both polypep­ tides associated in sets of 7 -9 .
Our findings favour the view that the apoproteins of LHCII are much more heterogenous than thought before.
Senescence-Related Changes in the Subcomplex Arrangement of the Major Light-Harvesting Chlorophyll a/b-Protein Complex of Photosystem II (LHCII) as Influenced by Cytokinin
Authors: Jackowski Grzegorz 
Published: August 2018

Abstract
The major light-harvesting chlorophyll a /b -protein complex of photosystem II (LHCII) from fresh barley leaves could be resolved by non-denaturing IEF into five trimeric subcomplexes designated 1 -5 in order of decrasing pi value. IEF-based analysis of PSII particles isolated from leaves in which the processes of senescence were induced by detachement and dark-incubation in the presence of water for 0 -8 days let us reveal that substantial rearrangements of LHCII organization took place throughout the course of senescence comprising a step-wise decline in relative abundance of subcomplexes 1 -3 (down to 0-58% of the initial abundance during 8 days of aging) and an increase in the relative abundance of the subcomplexes 4 and 5. Using SDS-PAGE and immunoblot analysis it was shown that the rearrangements were linked to the changes in the relative levels of LHCII apoproteins i.e. 26.7 and 25.6 kDa ones. The changes comprised the preferential disappearance of the 26.7 kDa polypeptide and an enrichment of 25.6 kD a one and most probably reflect the hetero­ geneity among LHCII apoproteins concerning their stability under the conditions of chi loss. Kinetin was able to repress the senescence-related rearrangements in LHCII subcomplex organization at late stages of aging (5 -8 days) by preventing over this time period the disappearance of 26.7 kD a polypeptide and the enrichement of 25.6 kDa one.
Lachnellins A, B, C, D, and Naphthalene-l,3,8-triol, Biologically Active Compounds from a Lachnellula Species (Ascomycetes)
Authors: Semar Martin , Anke Heidrun , Arendholz Wolf-Rüdiger , Veiten Robert , Steglich Wolfgang 
Published: August 2018

Abstract
In the course of our search for new biologically active metabolites, lachnellin A (1), a metabolite with high cytotoxic and antimicrobial activities, the structurally related lachnellins B, C and D (3, 4, 7), and naphthalene-1,3,8-triol (8), an inhibitor of malate synthase (EC 4.1.3.2), were isolated from submerged cultures of the ascomycete Lachnellula sp. A 32 -8 9 . The antimicrobial, cytotoxic and phytotoxic activities of lachnellin A depended on its reactivity and could be abolished by the addition of cysteine. The enzyme inhibiting activity of (8) was due to reactive intermediates during melanization and was no longer observed in the presence of serum albumin. In addition, rac-scytalone (9), (+)-trans-3,4-dihydro-3,4,8-trihy-droxy-1(2H)-naphthalenone (10). 2,5-dihydroxytoluene (11), and (R)-(-)-5-methylmellein (12) were obtained from the same source and biologically characterized.
Solid Phase Micro Extraction Technique Used for Collecting Semiochemicals. Identification of Volatiles Released by Individual Signalling Phyllonorycter sylvella Moths
Authors: Borg-Karlsona Anna-Karin , Mozuraitis Raimondas 
Published: August 2018

Abstract
The SPME (solid phase micro extraction) technique was used in the collection of volatiles released by calling females of the 4 -6 mm long tentiform leafminer moth Phyllonorycter sylvella (Lepidoptera, Gracillariidae). The volatiles released by the calling P. sylvella females were identified by GC-M S as a mixture of Z10-tetradecenyl acetate (92 %), E10-tetrad ecen yl acetate (2 %) and Z8 -tetradecenyl acetate (6 %). The amount of volatiles released by one calling female during three hours and collected on a polydimethylsiloxane fibre, was as large as the amount extracted from the glands of 20 females. The SPME technique gives the opportunity of continuously following the release of behaviour mediated signals from weak scented living organisms.
Extracts from Viscum and Crataegus are Cytotoxic against Larynx Cancer Cells
Authors: Sáenz M. T. , Ahumada M. C. , García M. D. 
Published: August 2018

Abstract
The effects of hexanoic extracts of Viscum cruciatum Sieber parasitic on Crataegus mono­gyna Jacq. (I), Crataegus monogyna Jacq. parasitized with Viscum cruciatum Sieber (II), and Crataegus monogyna Jacq. non-parasitized (III), and of a triterpenes enriched fractions isolated from I, II and III (CFI, CFII, CFIII respectively), on the growth of HEp-2 cells have been evaluated. All the samples demonstrated significant cytotoxic activity against cultured HEp-2 cells, and all of them showed a stronger in vitro activity than 6-mercaptopurine solution used as a positive control. With the hexanoic extracts I, II and III almost similar activity was obtained, but the hexanoic extract I showed comparably better results. Almost complete inhibition was observed with triterpenes-enriched fractions CFI, CFII and CFIII, at the dose 6 μg/ml, after 72 h of treatment. The most intense response was obtained with the triterpenesenriched fraction CFIII (from Crataegus monogyna non-parasitized), where the inhibition was 93%, but the fraction CFI and CFII showed similar inhibition (92% and 83%).
Identification of Lactobacillus Species Associated with Selected African Fermented Foods
Authors: Olasupo N. A. , Olukoya D. K. , Odunfa S. A. 
Published: August 2018

Abstract
Two hundred isolates of Lactobacillus were obtained from seven indigenous fermented foods namely: 'fufu' (fermented cassava), 'iru' (fermented African locust bean), 'kenkey' and 'ogi' (fermented maize), 'kunu-zarki' (fermented millet), 'ugba' (fermented African oil bean) and 'wara' (fermented skimmed cow milk). Lactobacillus species identified were Lacto­ bacillus casei (17.0%), L. lactis (4.5%), L. plantarum (41.5%), L. brevis (11.5%), L. jensenii (5.5%), L. acidophilus (3.5%) L. cellobiosus (5.0%), L. delbrueckii (2.5%), L. salivarius (3.5%), L. leichmannii (3.5%) and L. fermentum (2.0%). The commonest species isolated was L. plantarum. This paper highlight the importance of Lactobacillus in the processing of African fermented foods.
Effects of Compatible Solutes on Mammalian Cytochrome P450 Stability
Authors: Kühn-Velten W. Nikolaus 
Published: August 2018

Abstract
The sensitivity of pig cytochrome P450cl7 (CYP17), an endoplasmic reticulum membrane-bound enzyme, towards heat denaturation (48 °C) was measured by the P450-to-P420 spectral transition indicating conforma­tional labilization of the protein. Both sucrose and glucose have comparable and increasingly protective effects at concentrations ranging from 100 to 800 mм, while ectoine, a novel zwitterionic compatible solute which regulates bacterial osmoadaptation and stabilizes cytoplasmic enzymes, has a strong labilizing effect on CYP17 and favours its proteolytic inactivation possibly by electrostatic derangements. Sucrose or glucose, but not ectoine, can therefore eventually be proposed as compatible stabilizers of cytochrome P450 structures.
Identical Pyoverdines from Pseudomonas fluorescens 9AW and from Pseudomonas putida 9BW
Authors: Budzikiewicz H. , Kilz S. , Taraz K. , Meyer J.-M. 
Published: August 2018

Abstract
Pseudomonas fluorescens, Pseudomonas putida, Pyoverdine, Siderophore, Bacterial Classification From Pseudom onas fluorescens 9AW and from Pseudomonas putida 9BW identical pyo-verdine-type siderophores were isolated and their structures were elucidated by spectroscopic methods and degradation studies. These novel compounds are of interest as they contain L-threo-β-hydroxy histidine in their peptide chains, an amino acid sofar encountered in nature only rarely. The co-occurence of the same pyoverdine in different Pseudom onas species and its significance for the classification is discussed.
1-O-trans-Cinnamoyl-β-ᴅ -glucopyranose: Alcohol Cinnamoyltransferase Activity in Fruits of Cape Gooseberry (Physalis peruviana L.)
Authors: Latza Stefan , Berger Ralf G. 
Published: August 2018

Abstract
Methyl and ethyl cinnamate are aroma volatiles frequently occurring in fruits. Evidence was obtained that the enzymatic transfer of cinnamic acid to endogenous alcohols present in fruits (methanol, ethanol, 1-propanol) depended on energy-rich 1-O-glycosyl esters of cinnamic acid which served as acyl donor molecules. A putative 1-O-trans-cinnamoyl-β-ᴅ-gluco-pyranose; alcohol cinnamoyltransferase from cape gooseberry (Physalis peruviana L.) was active towards 1-O-trans-cinnamoyl-β-ᴅ-glucopyranose and 1-O-trans-cinnamoyl-β-ᴅ-gentiobiose. The enzyme was purified 290-fold by a protocol including ammonium sulphate precipi­tation, solubilization by Triton X-100, gel permeation and affinity chromatography on concanavalin A. The acidic glycoprotein (pI = 4.8) most probably is membrane bound. The distribution of alcohol cinnamoyltransferase activity in gel chromatography fractions suggests a native Mr of 75,000. For 1-O-trans-cinnamoyl-β-ᴅ-glucopyranose, an apparent Km of 69 μm was determined. At pH > 6.0, non-enzymatic transesterification superposes the enzymatic transformation.
Antagonistic Effects of α-Tocopherol and α-Tocoquinone in the Regulation of Cyclic Electron Transport around Photosystem II
Authors: Kruk J. , Burda K. , Radunz A. , Strzałka K. , Schmid G. H. 
Published: August 2018

Abstract
α-Tocoquinone (α-TQ ) and α-tocopherol (α-TOC) which cannot substitute for plastoquinone-9 (PQ-A) as an electron acceptor from photosystem II (PS II), influence the oxygen evolution activity of thylakoid membranes under continuous illumination. In the presence of the herbicide DCMU and the protonophore FCCP which stimulate cyclic electron transport around PS II, α-TQ decreased oxygen evolution whereas α-TOC enhanced it. The effects are attributed to a stimulation or an inhibition of cyclic electron transport around PS II by α-TQ and α-TOC, respectively. Results of flash light experiments on PS II preparations show that both α-TQ and α-TOC increased the d-parameter which describes the transition probability from the S3- to the S0-state of the oxygen-evolving complex, although to a smaller extent when PQ-A is added alone to the preparations. The initial S-state distribution in darkadapted samples was changed only upon PQ-A addition and influenced neither by α-TQ nor by α-TO C supplementation. These effects indicate different kinds of interaction of PQ-A, α-TQ and α-TOC with the PS II components. α-TQ increased and α-TOC decreased the “total miss” parameter both in the presence or absence of PQ-A. A possible site of interaction of α-TQ and α-TO C with the cyclic electron transport around PS II is suggested.
Characterization of Hydrogen Photoevolution in Oscillatoria chalybea Detected by Means of Mass Spectrometry
Authors: Abdel-Basset Refat , Bader Klaus P. 
Published: August 2018

Abstract
The filamentous non-heterocystous cyanobacterium Oscillatoria chalybea is capable to photoevolve molecular hydrogen when the cells are flushed to anaerobiosis with nitrogen or argon and exposed to short light flashes or continuous light. The light-induced hydrogen gas exchange of Oscillatoria chalybea has been investigated by direct determination of dynamic changes in the hydrogen partial pressure at m/e=2 in the H/D collector of a mass spectrometric set-up. By means of this technique also the time curves of the light-induced hydrogen gas exchange could be directly recorded. Depending on the chlorophyll concentration in the measuring cell we observed an increasing hydrogen content of the aqueous Oscillatoria suspension i.e. a dark evolution of molecular hydrogen. Upon the onset of light an initial rise of the H 2-signal was observed which was increasingly mixed or followed by a hydrogen uptake. The capability to photoevolve molecular hydrogen was maximal with young cultures and decreased with increasing age. The hydrogen evolution signals require relatively short dark adaptation to get pronounced; few seconds suffice for 2/3 of the hydrogen evolution amplitude. Prolonged dark adaptation maximizes the flash amplitudes. The hydrogen evolu­tion signals do not deactivate by low flash frequency Oscillatoria chalybea evolves molecular hydrogen following growth on nitrogen free or nitrate containing medium. Increase of the oxygen partial pressure of the assays completely abolishes the hydrogen evolution signals with an I50-value of 6 μm.
Andalusol, a Diterpenoid with anti-inflammatory Activity from Siderits foetens Clemen
Authors: Navarro A. , Heras B. de las 
Published: August 2018

Abstract
The anti-inflammatory activity of andalusol (ent-13(16),14-labdadiene-6α,8α,18-triol), a diterpenoid obtained from the acetone extract of Sideritis foetens Clemen, has been investigated. This compound was able to inhibit acute inflammatory processes induced by carrageenan or 12-O -tetradecanoylphorbol acetate (TPA ) after oral or topical administration. Quantitation of the neutrophil specific marker, myeloperoxidase (MPO), demonstrated that its topical anti-inflammatory effect was associated with reduction in neutrophil infiltration into inflamed tissues. Interaction of andalusol with leukocyte functions and histamine release from mast cells was analyzed in vitro. At a concentration of 100 μm andalusol decreased β-glucuronidase release from calcium ionophore A23187-stimulated rat peritoneal leukocytes. However, it failed to affect superoxide generation on TPA -stimulated leukocytes and it was non toxic to leukocytes up to 100 μm (assayed in terms of lactate dehydrogenase release). Andalusol produced a dose-dependent inhibition on histamine release from rat peritoneal mast cells stimulated by com pound 48/80 or calcium ionophore A23187. These results suggest that andalusol possesses an anti-inflammatory profile, and it is in part responsible for the anti-inflammatory activity attributed to this plant.
The Activity of Thymidine Phosphorylase in the Uterine Myomas and the Myometrium in Perimenopausal Women
Authors: Miszczak-Zaborska E. , Greger J. , Kowalska-Koprekh U. , Pajszczyk-Kieszkiewicz T. 
Published: August 2018

Abstract
The activity of thymidine phosphorylase (dThdPase) in the myometrium and uterine myomas has been investigated in perimenopausal women. Differences in the activity of dThdPase have been found depending on the myoma type, menopause stage and the phase of the menstrual cycle in which the surgery was performed. The enzyme in the cytoplasmatic soluble fraction obtain ed at 50 000 x g was the most active in cellular leiomyomas of the follicular phase, the least in adenomyom as of the luteal phase of the menstrual cycle, whereas its activity in myometrium was always unchanged. Greater differences can be observed in the activity of dThdPase after a partial purification of the enzyme from myomas. It seems that the increase in dThdPase activity may point to its correlation with transient, premalignant tumor which may later transform into malignant forms.
Methyl Valerenate, a New Sesquiterpenoid in the Essential Oil from Underground Parts of Valeriana officinalis L. s.l.
Authors: Woerdenbag Herman J. , Bos Rein , Hendriks Henk , Kruizinga Wim H. , Herrema Jan K. , Scheffer Johannes J. C. 
Published: August 2018

Abstract
A new valerenane sesquiterpenoid, methyl valerenate (1), was found in the essential oil from underground parts of Valeriana officinalis L. s.l. Spectral data of methyl valerenate, which was synthesized from valerenic acid (2), are given in this paper.
Cyclic Electron Flow Around Photosystem II as Examined by Photosynthetic Oxygen Evolution Induced by Short Light Flashes
Authors: Gruszecki W. I. , Strzałka K. , Radunz A. , Schmid G. H. 
Published: August 2018

Abstract
Photosynthetic oxygen evolution from photosystem II particles was analyzed as consequence of a train of short (5 μs) flashes of different light quality and different intensities to study cyclic electron flow around photosystem II. Damped oscillations of the amplitudes of O2-evolution corresponding to a flash sequence were fitted numerically and analyzed in terms of a nonhomogeneous distribution of misses, represented by the probability parameter αi. Application of red light, known to promote cyclic electron flow around photosystem II (Gruszecki et al., 1995) results in a considerable increase of all αi, indicating that at the molecular level the misses may be interpreted as resulting from a competition for the reduction of oxidized P680 between cyclic electron flow and the electron flow coming from the water splitting enzyme. In accordance with previous findings, application of light flashes of the spectrum covering the absorption region of carotenoids resulted in an inhibition of cyclic electron flow and a pronounced decrease of the level of the miss parameter. Possible molecular mechanisms for the activity control of this cyclic electron transport around photosystem II by carotenoids are discussed.
Structure -Cytotoxicity Relationships of a Series of Natural and Semi-Synthetic Simple Coumarins as Assessed in Two Human Tumour Cell Lines
Authors: Kolodziej Herbert , Kayser Oliver , Woerdenbag Herman J. , Uden Wim van , Pras Niesko 
Published: August 2018

Abstract
The cytotoxicity of 22 natural and semi-synthetic simple coumarins was evaluated in GLC4, a human small cell lung carcinoma cell line, and in COLO 320, a human colorectal cancer cell line, using the microculture tetrazolium (MTT) assay. With IC50 values > 100 μᴍ , following a continuous (96h) incubation, most coumarins exhibited only low cytotoxicity. Several compounds, however, displayed significant potencies. As far as the structure -cytotoxicity relationship is concerned, it is conspicuous that all the potentially active natural compounds possess at least two phenolic groups in either the 6,7-or 6,8-positions. In addition, the 5-formyl-6-hydroxy substituted semi-synthetic analogue was found to be potent, reflecting the importance of at least two polar functions for high cytotoxicity.
Mechanism of Free and Conjugated Neocarzinostatin Activity: Studies on Chromophore and Protein Uptake Using a Transferrin-Neocarzinostatin Conjugate
Authors: Schönlau Frank , Maibücher Axel , Köhnlein Wolfgang , Garnett Martin C. 
Published: August 2018

Abstract
Targeting studies using the anti-cancer agent neocarzinostatin (NCS), conjugated to anti­ bodies have shown relatively poor specificity. From the literature, it is unclear whether NCS mediates its effects either in conjugated or unconjugated form. In the present work we have used a conjugate of NCS with transferrin, a biological ligand with a well defined endocytic route, to probe these mechanisms. NCS was covalently coupled to transferrin using the heter­ obifunctional reagent sulfo-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC) and 2-iminothiolane to give a stable thioether-linked conjugate with a ratio of 1.6 mol of NCS per mole of transferrin. The binding activity of transferrin was completely retained. Conjugation of NCS to transferrin resulted in an apparent enhancement of cytotoxicity. However, incubation with excess transferrin had no influence on the observed enhanced toxicity, indicating that endocytosis is not responsible.
Further experiments demonstrated that the apparent enhancement was dependent on incubation conditions and not an effect due to endocytosis of ligand. Studies where apo-NCS competed with holo-NCS and transferrin strongly indicated that the cytotoxicity of both NCS and conjugate is mediated by direct entry of the dissociated chromophore into the cell.
Definition of Essential Amino Acid Residues in the Recognition of a Peptide by a Mouse Monoclonal Antibody
Authors: Rosanó Laura , Di Modugno Francesca , Romagnoli Giulia , Chersi Alberto 
Published: August 2018

Abstract
A mouse monoclonal antibody reacting in ELISA with a synthetic peptide representing a linear amino acid stretch of the protein antigen was tested on all overlap­ ping 5-mer to 9-mer fragments of the peptide, as prepared by multi-pin synthesis. Analysis of the binding data suggests that several residues in the peptide might be relatively unrelevant for recognition, while few others seem to play a critical role as key residues. On the basis of such observations, we attempted to reconstruct an alternative essential epitope by introducing multiple amino acid substitutions in the 9-mer peptide exhibiting the best binding activity, and then tested its ability to be recognized by the monoclonal antibody.
Chemical Constituents of Madhuca pasquiery
Authors: Kamperdick Christine , Adam Günter , Hong Van Nguyen , Sung Tran Van 
Published: August 2018

Abstract
Four triterpenoids, the scarce nortriterpenoid platanic acid, two flavonoids and 2,4-dihy-droxyphenylacetic acid methyl ester, hitherto unknown as a natural product, were isolated from Madhuca pasquiery. The structures were established by means of mass and NMR spectroscopy.
Phenolic Compounds from Ageing Shoots of Picea abies
Authors: Kraus Christine A. , Spiteller Gerhard 
Published: August 2018

Abstract
The influence of ageing on the amount and composition of phenolic compounds and their glucosides was studied in one to five-year-old shoots of Picea abies.
The total content of phenolics increased remarkably within the first two years of growth. In this period cinnamic acid derivatives were dominating, but beginning with the end of the first vegetation period a dramatic increase of acetophenones was observed. Obviously at the end of the first vegetation period the cinnamic acid derivatives are subjected to oxidation resulting in an increase of acetophenones.
Biogenesis of the Pyoverdin Chromophore
Authors: Böckmann M. , Taraz K. , Budzikiewicz H. 
Published: August 2018

Abstract
After growing Pseudomonas aeruginosa in the presence of 2 ,4-[4-15N]-diaminobutyric acid (Dab) its incorporation into the quinoline chromophore of the pyoverdin produced by this bacterium could be shown by mass and NMR-spectroscopic techniques. In combination with earlier results it can thus be stated that the precursor of the chromophore is a condensation product of ʟ-Dab and ᴅ-Phe or ᴅ-Tyr. A synthesis for [4 -15N ]-Dab is described.