bluuebunny/crossref_metadata_2025 huggingface dataset:
Neue Untersuchung über Inhaltsstoffe aus Aloe-und Rhamnus-Arten, XV [1] Homonataloin A und B aus Aloe lateritia: Reindarstellung, Konstitutions-und Konfigurationsaufklärung der Diastereomeren / A New Investigation on Constituents of Aloe and Rhamnus Species, XV [1] Hom onataloins A and B from Aloe lateritia: Isolation, Structure and Configurational Determ ination of the Diastereomers
Authors: Rauwald Hans-W. , Niyonzima Deo-D.
Published: August 2018

From the leaf exudate of Aloe lateritia ENGLER the C-glucosyl com pounds homonataloin, aloeresin A and aloesin (synon. aloeresin B) were isolated together with the anthraquinone nataloeem odin-8-methylether and spectroscopically identified. Hom onataloin, widely distributed in Aloe species, was separated into homonataloin A and B by combined TLC and DCCC. In their 1 D and 2D 1H NMR spectra only the shifts of the 2′-hydroxyl protons of both glucosyl residues differ significantly, indicative of 10 S (A) resp. 10 S (B) configurations. In both com pounds the anthrone is in β-position of the D-glucopyranosyl, as determined by the large coupling constants of the anomeric protons. The 13C NMR signals are unambiguously assigned by the use of DEPT, APT and gated-decoupling methods. Only the chemical shifts of C -11 and C -14 show significant differences between both diastereomers due to the adjacent 2′-sugar hydroxyls. The two homonataloins differ mostly in optical rotation and circulardichroism due to different configurations at C - 10 of the anthrone part. The absolute configurations of the diastereomers are determined by correlation of their CD spectra with the CD spectra of the structural analogues 7-hydroxyaloins A and B, which shows that hom onataloin A is the 10 S, 1′S-compound and that homonataloin B has 10 R, 1′S-configuration.
Resonance Raman Spectroscopic Evidence for the Identity of the Bacteriochlorophyll c Organization in Protein-Free and Protein-Containing Chlorosomes from Chloroflexus auvantiacus
Authors: Hildebrandt Peter , Griebenow Kai , Holzwarth Alfred R. , Schaffner Kurt
Published: August 2018

Protein-free and protein-containing chlorosomes from Chloroflexus aurantiacus, strain Ok-70 fl, were studied by resonance Raman (RR) spectroscopy. Both preparations gave the same spectra of the bacteriochlorophyll c (BChl c) chromophores in the range of 1200-1750 cm-1. This strongly corroborates previous evidence [Griebenow et al., Z. Naturforsch. 45c, 823-828 (1990), and references therein] that the three-dimensional structure of the antenna complexes is not determined by direct interaction with protein but rather is due to BChl c selforganization. The analysis of the coordination-sensitive marker bands of the chlorin macrocycle reveals a mixed six- and fivefold ligation of the Mg ion. Based on two C = O stretching vibrations originating from a free and a Mg-bound C-9 keto group, it is concluded that only in the six-coordinated state the keto group serves as an axial ligand to the Mg ion of a neighbouring chlorin. The second permanently bound axial ligand is attributed to the C-2a hydroxyl group.
Turnover of the D-1 Reaction Center Polypeptide from Photosystem II in Intact Spruce Needles and Spinach Leaves
Authors: Godde Doris , Schmitz Heribert , Weidner Manfred
Published: August 2018

A new method is presented to follow the turn over of the D-1 reaction center polypeptide of photosystem II in intact spruce needles or spinach leaves by incorporation of [14C]leucine. Like in other organisms the synthesis and degradation of this protein is strongly light-dependent and very fast. The synthesis rate under moderate light intensities in healthy spruce needles is about 9 nmol [14C]leucine mg-1 Chl h-1. The half-life time of the D-1 protein under these conditions is less than 30 min. In order to demonstrate the usefulness of this method for the stress physiology of photosynthesis, first experiments are shown comparing the turnover of the D-1 protein in spruce needles with different age and different degree of dam age.
Epoxyheptadecadienes Identified as Sex Pheromone Components of Tephrina arenacearia Hbn. (Lepidoptera: Geometridae)
Authors: Tòth M. , Löfstedt C. , Hansson B. S.
Published: August 2018

(Z ,Z )-3,9-cis-6,7-Epoxyheptadecadiene, and (Z,Z)-6,9-cis -3,4-epoxyheptadecadiene were identified by gas chromatography/flame ionization detection-electroantennographic detection (GC/FID-EAD) and coupled gas chromatography-mass spectrometry (GC-MS) from abdominal tip extracts of Tephrina arenacearia (Lepidoptera: Geometridae), an alfalfa pest. In gas chromatography/flame ionization-single sensillum detection (GC/FID-SC) analyses, specific olfactory receptor cells were found for (Z,Z)-6,9-cis-3,4-epoxyheptadecadiene, and tricosane. Synthetic samples of racemic (Z,Z )-6,9-cis-3,4-epoxyheptadecadiene attracted large numbers of male T. arenacearia into traps. Best catches were observed at 100-1000 μg dosages. The addition of (Z,Z,Z)-3,6,9-heptadecatriene did not influence catches.

(Z,Z,Z)-3,6,9-Heptadecatriene and (Z,Z)-6,9-cis-3,4-epoxyheptadecadiene were also identified in the pheromone gland extract of Chiasma clathrata, an other geometrid pest of alfalfa.
Temperature Dependence of the Rotational Mobility of the Sugar and Water Molecules in Concentrated Aqueous Trehalose and Sucrose Solutions
Authors: Karg N. , Lüdem ann H.-D.
Published: August 2018

Carbon-13 and deuteron spin lattice relaxation times T1 of concentrated solutions of trehalose and sucrose in heavy water are given as function of temperature. From the temperature dependence of the T1 ideal glass transitions temperatures To are derived. For both compounds the To derived for the disaccharides are at high concentrations larger than the To of the water molecules.
Substrate Specificity In The Fungal Metabolism Of Prenylated Flavonoids
Authors: Tahara Satoshi , Ingham John L. , Mizutani Junya
Published: August 2018

The prenylated flavonoids, topazolin [5,7,4′-trihydroxy-3-methoxy-6-(3,3-dimethylaIlyl)- flavone], piscerythrone [5,7,2′,4′-tetrahydroxy-5′-methoxy-3′-(3,3-dimethylallyl)isoflavone] and piscidone [5,7,4′,5′-tetrahydroxy-2′-methoxy-6′-(3,3-dimethylallyl)isoflavone] were metabolized by Aspergillus flavus and Botrytis cinerea to give a variety of products. Topazolin and piscerythrone were converted by both fungi to compounds similar to those previously obtained from luteone (6-prenyl) and licoisoflavone A (3′-prenyl) respectively. The 6′-prenylated isoflavone piscidone was metabolized only by B. cinerea to give the corresponding dihydropyrano- isoflavone as a major product. Neither fungus was found to metabolize the 8-prenylated pyranoflavanonol lupinifolinol
Cell Free Synthesis Of Ö-Succinylbenzoic Acid In Protein Extracts From Anthraquinone And Phylloquinone (Vitamin K1) Producing Plant Cell Suspension Cultures. Occurrence Of Intermediates Between Isochorismic And o-Succinylbenzoic Acid
Authors: Simantiras Michalis , Leistner Eckhard
Published: August 2018

Cell free protein extracts from heterotrophic anthraquinone (“Rubiatype”) producing cell suspension cultures of three different Galium species and from a photoautotrophic phylloquinone (vitamin K ,) producing cell suspension culture of Morinda lucida Benth. (Rubiaceae) catalyzed the synthesis of o-succinylbenzoic acid (OSB) from isochorismic acid and a-oxoglutaric acid in the presence of thiamine diphosphate and Mn2+. At least two intermediates in the conversion of isochorismic to o-succinylbenzoic acid were detectable. One of these intermediates is likely to be identical to 2-succinyl-6-hydroxy-2,4- cyclohexadiene-l-carboxylate (SHCHC), a metabolite known to occur in bacterial mutants (menD+) blocked in o-succinylbenzoic acid synthesis. The structure of the second intermediate is as yet unknown. A third intermediate may also occur
o-Succinylbenzoate: Coenzyme A Ligase, an Enzyme Involved in Menaquinone (Vitamin K2) Biosynthesis, Displays Broad Specificity
Authors: Sieweke Hans-Jürgen , Leistner Eckhard
Published: August 2018

o-Succinylbenzoate: coenzyme A ligase, an enzyme involved in menaquinone biosynthesis, was purified from Mycobacterium phlei and characterized with respect to isoelectric point, molecular weight, pH optimum, temperature optimum and kinetic data. The enzyme hydrolyses ATP to AMP. The substrate and cofactor specificity of the enzyme was tested with analogues of o-succinylbenzoic acid, different nucleotides, thiols and divalent cations. The enzyme appears to possess broad specificity for substrates and cofactors.
Duplicated Sequence Elements and Their Function in Plant Mitochondria
Authors: Wissinger Bernd , Hiesel Rudolf , Schobel Werner , Unseld Michael , Brennicke Axel , Schuster Wolfgang
Published: August 2018

A considerable portion of the plant mitochondrial DNA is derived from genome internal duplications. Many of these amplified sequences determine functions of transcription and processing. Among these are promoter regions, sequences defining the 3′ ends of stable mRNAs, potential RNA processing sites and intron domains. Simultaneously, some of these repeated sequences can be active sites of recombination in plant mitochondria. Such duplicat­ed control regions may simplify coordinate expression of different genes.
Milestones in the Development of Herbicide Safeners
Authors: Stephenson Gerald R. , Yaacoby Tuvia
Published: August 2018

The concept of using chemical safeners to improve herbicide selectivity became widely known in 1969 with the introduction of naphthalic anhydride (NA) to improve the tolerance of maize to thiocarbamate herbicides. Soon thereafter dichlormid was also developed as a safener for thiocarbamates in maize. At present there are at least eight different chemical safeners that have been developed commercially. Many of these safeners have been most effec­tive for chloroacetamide or thiocarbamate herbicides in monocotyledonous crops such as maize or sorghum. Some are like dichlormid and have been developed as physiologically selec­tive safeners that can be combined in the formulation with the herbicides. Others, like NA , are either less selective or less active in the soil and must be used as dressings on the crop seed. Most of the presently used safeners are for soil active herbicides. The challenge for the future will be to develop safeners that are effective for the newer postemergence herbicides in dicoty­ledonous as well as monocotyledonous crops.
Chemistry and Structure-Activity Relationships of Herbicide Safeners
Authors: Kőmíves Tamás , Hatzios Kriton K.
Published: August 2018

The discovery and commercial success of safeners against thiolcarbamate herbicide injury to corn has stimulated a rapid progress and opened new possibilities for further research and development in the last decade. Compounds with new chemistry, increased efficacy, and a broader selectivity spectrum were synthesized and developed for agricultural use. Structure-activity relationship studies helped to optimize their chemical properties and to understand their biological modes of action. Several examples indicate close similarity between chemical structures possessing herbicidal and safener properties. In some cases this differentiation may be marginal, as shown in crops pretreated with low herbicide doses leading to safening effects. In other examples, however, structural optima for safening and herbicidal efficacy can be clearly differentiated.
Oxabetrinil Reversal of Metolachlor and Acid Soil Stress
Authors: Wilkinson R. E. , Duncan R. R.
Published: August 2018

Metolachlor and excess Mn2+ (acid soil stress) induce alterations in gibberellin precursor biosynthesis that can explain the morphological responses to these physiological stresses. Oxa­betrinil protects sorghum [Sorghum bicolor (L.) Moench] from the influence of metolachlor and excess Mn2+. Sorghum cultivar variations in response to excess Mn2+ are explicable as dif­ferential rates of ent-kaurene biosynthesis between acid soil sensitive and tolerant cultivars. Concentrations of Mn2+ present in vegetative leaves and reproductive stem tissues were not different. Therefore, cultivar differences in ent-kaurene biosynthesis explain the acid soil toler­ance differences rather than differential Mn2+ absorption, translocation, and/or compartmentation. Metolachlor and safener responses are found in cellular compartments and tissues that do not match a decreased herbicide concentration through absorption, transport, or degrada­tion as a sole mode of action for safeners.
Alkaloids of Adenocarpus hispanicus (Lam.) DC Varieties
Authors: Veen Gerhard , Greinwald Roland , Cantó Paloma , Witte Ludger , Czygan F.-C.
Published: August 2018

Alkaloid extracts from different organs of Adenocarpus hispanicus ssp. hispanicus and Adenocarpus hispanicus ssp. gredensis were analyzed by capillary GC. Twenty-four compounds could be identified by the high sensitive method of GLC-MS: the pyrrolizidine alkaloids decorticasine, N-acetylnorloline and N-butyrylnorloline, the bipiperidyl alkaloid ammodendrine, the phenylethylamine tyramine and 19 quinolizidine alkaloids. In contrast to Adenocarpus complicatus, Adenocarpus foliolosus and Adenocarpus viscosus the alkaloid pattern of Adenocarpus hispanicus is characterized by the occurrence of quinolizidine alkaloids with sparteine predominating in the leaves and numerous dehydroderivatives of sparteine. Remarkable is the total absence of adenocarpine which was described as a main compound of the three former species. Our results strongly support the opinion that the genus Adenocarpus should be divided into two phytochemical groups.
Formation of 1,3-Dihydroxy-N-methylacridone from N-Methylanthraniloyl-CoA and Malonyl-CoA by Cell-Free Extracts of Ruta graveolens
Authors: Baumert Alfred , Porzel Andrea , Schmidt Jürgen , Gröger Detlef
Published: August 2018

N-Methylanthraniloyl-CoA was synthesized via N-succinimidyl N-methylanthranilate and subsequent transesterification with CoA-SH . This compound was characterized by LSIMS and NMR data. An enzyme preparation from cell suspension cultures of Ruta graveolens catalyzed the formation of 1,3-dihydroxy-N-methylacridone from N-methylanthraniloyl-CoA and malonyl-CoA with a pH optimum of 7.5.
Maturation and Responsiveness to Extracts of Corpora Allata from Male Locusta migratoria containing Allatotropic Factors
Authors: Lehmberg Elisabeth , Ferenz Hans-J. , Applebaum Shalom W.
Published: August 2018

Corpora allata (CA) from male Locusta migratoria were tested for their ability to synthesize juvenile hormone (JH) and to respond to stimulating brain/corpora cardiaca (CC) extracts under in vitro conditions. We found that a preincubation of the CA of both sexes at 4 °C for 24 h lowers their basal rate of synthesis and retains their responsiveness to allatotropic factors. Male CA can be stimulated by brain/CC extracts as well as female CA. JH biosynthesis stimulating factors are also present in male brain/CC extracts. Thus such extracts from male locusts can be used for the isolation of locust allatotropin. Furthermore male locust CA are appropriate for bioassaying such allatotropic factors.
Lipophilic Phenolic Constituents from Helichrysum Species Endemic to Madagascar
Authors: Randriaminahy Michel , Proksch Peter , Witte Ludger , Wray Victor
Published: August 2018

Eight species of the genus Helichrysum, all of them endemic to Madagascar, were analyzed for lipophilic phenolic constituents deposited on the surfaces of leaves and stems. A total of 35 compounds was isolated and identified by spectroscopic means. Chalcones (10) comprised the largest group of compounds encountered, followed by flavonols (8), flavanones (7), flavones (4), benzophenones (3) and phloroglucinol derivatives (3). Many of the flavonoids were characterized by unsubstituted B-rings and/or C- or O-bound prenyl or neryl substituents. The Helichrysum species analyzed in this study are very similar to African species of this genus with regard to their lipophilic phenolic constituents. The phenolic com pounds studied thus appear to be conservative chemical characters of Helichrysum that were retained more or less unchanged during the origin of endemic taxa in Madagascar.
Occurrence of Secondary Carotenoids in PS I Complexes Isolated from Eremosphaera viridis De Bary (Chlorophyceae)
Authors: Vechtel Burkhard , Pistorius Elfriede K. , Ruppel Hans Georg
Published: August 2018

Photosystem I complexes of Eremosphaera viridis De Bary (Chlorophyceae, Chlorococcales) were isolated and partially characterized. In the isolated PS I complexes, peptides of 64-60, 26, 23, 20, 15, 11 and 8.5 kDa could be detected. When Eremosphaera was grown under regular conditions the pigment composition of the isolated PS I complexes was similar to that found in PS I complexes from other green algae. However, when Eremosphaera was grown under nitrogen deficient conditions, PS I complexes contained the secondary carotenoids canthaxanthin and traces of astaxanthin and echinenone in addition to β-carotene, violaxanthin and lutein. The results presented indicate that the secondary carotenoids are associated with the LHC I of PS I. To our knowledge this represents the first report about the association of secondary carotenoids with light harvesting pigment protein complexes of green algae.
Reactions of Cloned Poplars to Air Pollution: Premature Leaf Loss and Investigations of the Nitrogen Metabolism
Authors: Ballach Hans-Joachim , Oppenheimer Simone , Mooi Jan
Published: August 2018

Young poplar cuttings (Populus nigra L. cv. Loenen and P. maximowiczii Henry x P. nigra L. cv. Rochester) were exposed for six weeks in open-top chambers to realistic concentrations of pollutant mixtures: 1) control; 2) SO2/NOx; 3)O3/ NOx and 4)SO2/O3/NOx. In this sequence of fumigation variants, the degree of influence of the various parameters of the nitrogen metabolism and of premature leaf drop increased very frequently compared to the control plants, P. nigra L. proving to be the more sensitive species.

The elevated Kjeldahl nitrogen content of the fumigated leaves was accompanied by either an increase in free amino acids or in total protein or, in the case of particularly large rises (SO2/O3/NOx variants), by increases in both substance groups. Proteolytic processes as a cause of the elevated content of free amino acids could be excluded to a large extent. A diminished de novo synthesis of proteins obviously led to a shift in the amino acid/protein relationship. In the younger fumigated leaves, the total concentration of free amino acids exceeded the values of the older leaves. The elevated amino acid content of the fumigated leaves was produced to a high degree by the glycolate pathway and the Krebs cycle. The increased turnover of the carbon skeletons was connected with a drastic starch degradation, especially in the older leaves.

The interaction of the amino acid and carbohydrate metabolisms is probably an important regulator in the promotion of rapid growth of young leaves in order to compensate premature leaf loss.
Differences in Membrane Order between C 3 H 10 T1/2 Cells and Their Transformed Counterparts as Measured by EPR
Authors: Grossi G. F. , Durante M. , Napolitano M. , Lanzone A. , Riccardi P. , Santini M. T.
Published: August 2018

Membrane order of mouse embryo fibroblasts and their ionizing radiation and chemically transformed counterparts was investigated using EPR spectroscopy after labeling the membrane of the cells with the fatty acid spin label, 5-nitroxy stearic acid. The EPR spectra were recorded at temperatures ranging from 18 to 38 °C for both control and transformed cells. The distance between the outer hyperfine splitting (2 T′||), which is used as an indicator of membrane order, varies in these two cell types. Below 28 °C, 2T′II is higher in transformed fibroblasts than in normal cells, whereas above this temperature membrane order is the same. Lipid analysis as carried out by the measurement of the cholesterol/membrane proteins and sphingomyelin/lecithin ratios, showed no difference in the amounts of the main membrane rigidifiers. These findings suggest that cell transformation of mouse fibroblasts induced by radiation or chemicals may produce alterations in the cell membrane, as evidenced by variations in its order at low temperature. These measured differences are presumably not attributable to its fatty acids composition but to its glycoproteins content, since changes in membrane regidifiers were not observed between normal and transformed cells.
Hypothallin, Ein Weiterer Vertreter Eines Aminosäure-Aminoalkohol-Esters Aus Der Krustenflechte Schismatomma Hypothallinum
Authors: Huneck Siegfried , Porzel Andrea , Schmidt Jürgen , Follmann Gerhard
Published: August 2018

Hypothallin, a metabolite of the lichen Schismatomma hypothallinum (Lecanactidaceae, Opegraphales) has been structurally elucidated as (-)-N-benzoyl-ʟ-phenylalaninyl-N′- benzoyl-ʟ-leucinate by NMR and MS and by synthesisᴅ
Genistifolin And Other Iridoid Glucosides From Linaria Genistifolia (L.) Mill.
Authors: Ilieva Emilia , Handjieva Nedjalka , Popov Simeon
Published: August 2018

The new iridoid genistifolin and the known antirrinoside and linarioside have been isolated from aerial parts of Linaria genistifolia (Scrophulariaceae). TLC data indicate the presence of 6-deacetylgenistifolin
Accumulation Of Phenolic Compounds In Leaves Of Tomato Plants After Infection With Clavibacter Michiganense Subsp. Michiganense Strains Differing In Virulence
Authors: Beimen Andrea , Bermpohl Andreas , Meletzus Dietmar , Eichenlaub Rudolf , Barz Wolfgang
Published: August 2018

Infection experiments using tomato (Lycopersicon esculentum cv. Moneymaker) plants and three strains of Clavibacter michiganense subsp. michiganense were conducted. The bacterial isolates differed in plasmid status, virulence (measured as wilting index and as reduction of plant biomass) and the ability to colonize the plants. Differences in the expression of exopolysaccharides and the exoenzymes endocellulase, polygalacturonase, and xylanase, respectively, were not found with the bacterial isolates. As infection-induced responses of the plants timedepending increases in soluble phenolic material, including chlorogenic acid and rutin, in the steroid alkaloid tomatine and in cell wall-bound cinnamic acids were found. In the latter fraction p-coumaric, ferulic and especially caffeic acid were the main constituents. All plant responses were preferentially expressed in the compatible interaction. Sesquiterpenoid phytoalexins were not found in the infected plant tissues. The relation between bacterial pathogenicity and plant responses is discussed
Acid Dnase Activities In Peripheral, Mononuclear Blood Cells: A Possible Parameter To Detect Proliferating Cell Populations
Authors: Reitz Manfred , Gutjahr Peter
Published: August 2018

After electrophoresis in DNA -containing polyacrylamide gels, two acid DNase activities can be detected in peripheral, mononuclear cells of the human blood. One of these acid DNase activities correlates with cell proliferation; its isoelectrical point is at pI 7.4. By means of this DNase activity, a quantity of less than 1% leukemic cells can be detected. The increased acid DNase activity can indicate the proliferation of malignant cell populations and possibly the proliferation of cell populations during immunological reactions
Two Phases Of Ferricyanide Reductase Activity In Ehrlich Cell Plasma Membranes
Authors: Castillo-Olivares Antonio del , Márquez Javier , de Castro Ignacio Núñez , Medina Miguel Angel
Published: August 2018

Ehrlich cell plasma membrane vesicles have a ferricyanide reductase activity that shows two phases. These two phases were kinetically characterized. Evidence is presented for a differential effect of trypsin on both phases
Soluble Carbohydrates in Mycorrhized and Non-Mycorrhized Fine Roots of Spruce Seedlings
Authors: Rieger Andreas , Guttenberger Martin , Hampp Rüdiger
Published: August 2018

We present results on the compartmentation of carbohydrates such as sucrose, glucose, fructose, and mannose in different parts of an ectomycorrhiza established between Picea abies and Amanita muscaria and compare it with non-mycorrhized fine roots. Lyophilized mycorrhizas and fine roots (< 2 mm length) were dissected into about 0.5 mm thick slices which represent 4 zones of different physiological functions. The total amount of the analyzed carbohydrates was about 30% higher in non-mycorrhized (n-myc) compared to mycorrhized (myc) fine roots, with sucrose being the dominating sugar in both root types. A longitudinal distinction of sucrose pools showed lowest levels in the middle parts of a mycorrhiza, which represent areas of most intense symbiotic interaction. Fine roots without fungal infection did not show longitudinal variations in sugar content.
The Vacuolar Localization of Grapevine Peroxidase Isoenzymes Capable of Oxidizing 4-Hydroxystilbenes
Authors: Calderón Antonio A. , García-Florenciano E. , Pedreño María A. , Muñoz Romualdo , Barceló A. Ros
Published: August 2018

Keywords

A study of the subcellular localization of peroxidase isoenzymes capable of oxidizing 4-hydroxystilbenes to viniferin-type compounds has been carried out in cultured cells derived from Vitis vinifera cv. Gamay berries. The study revealed that these isoenzymes are apparently located, in soluble form, in the vacuolar sap and are strongly inhibited by vacuolar anthocyani( di)ns in the concentration range found in planta. These results suggest that the inhibition of the 4-HS peroxidase system in vacuoles, as a consequence of anthocyani(di)n accumulation, could be responsible for the loss of viniferin production potential which accompanies grape berry veraison.
Analysis of Phenolics of Bud Exudates of Populus cathayana and Populus szechuanica by GC-MS
Authors: Greenaway W. , English S. , May J. , Whatley F. R.
Published: August 2018

Analysis of GC-MS data revealed 58 com ponents of bud exudate from P. cathayana (Section Tacamahaca) and 40 components of bud exudate from P. szechuanica (Section Tacamahaca) of which 47 and 35 respectively were phenolics. The bud exudates were very similar in composition, containing flavanones and chalcones (61% and 51% respectively), flavones (15% and 12%) and pentenyl caffeates (11% and 6%). The major single component of the exudate of both poplars was pinobanksin- 3-acetate (26% and 33%). The bud exudates of P. cathayana and P. szechuanica are similar to those of European and American Section Aigeiros poplars and unlike those of North American Section Tacamahaca poplars.
In vitro Demonstration of a Biosynthetic Sequence for the Cruciferae Phytoalexins
Authors: Devys Michel , Barbier Michel
Published: August 2018

Periodate-induced degradation of cyclobrassinin monosulphoxide gives brassilexin in 40% yield. The sequence: cyclobrassinin to brassilexin through cyclobrassinin sulphoxide is now demonstrated for the group of phytoalexins found in the Cruciferae.
X-Ray Studies on Phospholipid Bilayers. XII. Interactions of Pentachlorophenol with Myelin
Authors: Suwalsky M. , Villena F. , Montoya G. , Garrido C. , Sánchez I. , Neira F.
Published: August 2018

Pentachlorophenol (PCP) is a widely used pesticide, particularly for the preservation of wood. Given its high toxicity and resistance to degradation it has become a dangerous environmental pollulant. Due to its high lipophilicity, PCP is able to partition into the lipid bilayer of cell membranes disrupting several vital functions. The present research was concerned with the effects that the chronic administration of PCP could produce in vivo to the sciatic nerve of rats. X-ray diffraction patterns obtained from freshly dissected and dried sciatic nerves of PCP treated rats did not show significant differences in their reflections with respect to those present in the patterns from untreated animals. However, morphological studies performed by optical and electron microscopy showed degenerative changes in about 10% of the A and B type of nerve fibers.
Purification and Characterization of Nitrate Reductase from the Halophile Archaebacterium Haloferax mediterranei
Authors: Alvarez-Ossorio María C. , Muriana Francisco J. G. , Rosa Francisco F. de la , Relimpio Angel M.
Published: August 2018

Nitrate reductase is induced in cells of Haloferax mediterranei by the presence of nitrate upon anaerobic conditions. This enzyme was purified more than 35-fold with a yield of 49%. Densitograms of polyacrylamide gel electrophoresis show the preparation to be 85% purity. The best enzyme preparation has a specific activity of 13.6 U /m g protein. It is the first halophilic nitrate reductase that has been purified near to homogeneity. The purification consists of five steps: an ammonium sulphate precipitation and four successive gel chromatographies with Sepharose CL-4 B, calcium phosphate, DEAE-Sephacel and Sephacryl S-200. An average Mr of 170,000 was estimated by gel chromatography and non-denaturing gel electrophoresis. Effectiveness of electron donors, cofactors and inhibitors are reported. At low salt concentration the halophilic nitrate reductase was inactivated following first-order kinetics. The Km for nitrate depends on salt concentration and shows values in the range from 2.5 to 6.7 mM.
Differential Inhibition and Rephasing of Photosystem II Electron Acceptor Side by Monohalogenated Acetates of Different Hydrophobicity
Authors: Xu Chunhe , Zhu Yong , Govindjee
Published: August 2018

We demonstrate here that monohalogenated acetates (MFA , monofluoroacetate; M CA, monochloroacetate; MBA, monobromoacetate) are unique probes of the electron acceptor side of the photosystem II (PS II) reaction center: (1) they differentially inhibit the reoxidation of the reduced primary plastoquinone electron acceptor, QA
-, by the secondary plastoquinone electron acceptor QB, and increase the equilibrium [QA
-] in the order: MBA ≳ M CA > MFA; and (2) M CA and MBA rephase the PS II electron acceptor side, a rather unusual effect. This results in flash number dependence of [QA
-] with maxima at even flashes to change to odd flashes. Furthermore, we demonstrate a correlation between the inhibitory activity of the halogenated acetates with their hydrophobicity (i.e., partition coefficient).
Effect of Cinnamic and Acrylic Acids′ Derivatives on Luminol-Enhanced Chemiluminescence of Neutrophils
Authors: Czuba Z. , Krol W. , Scheller S. , Shani J.
Published: August 2018

Fourteen derivatives of cinnamic and acrylic acids were evaluated for their ability to modulate chemiluminescence, evoked by neutrophils that had been exposed to luminol and phorbolmyristate- acetate. Compounds with one or two hydroxyl groups on the phenyl ring demonstrated significant inhibition of the chemiluminescence, but this inhibition was diminished by methoxylation. Saturation of the double bond in the aliphatic chain of cinnamic acid at C 6 - enhanced the chemiluminescence to a small degree. All three acrylic acid derivatives demonstrated a marked inhibition of the luminol chemiluminescence, indicating that characteristics of the heterocyclic ring is of utmost importance in this activity.
Electrostatic Potential Barrier in Asymmetric Planar Lipopolysaccharide/ Phospholipid Bilayers Probed with the Valinomycin-K+ Complex
Authors: Seydel Ulrich , Eberstein Wolfram , Schröder Guido , Brandenburg Klaus
Published: August 2018

Using the carrier-ion complex valinomycin-K+, current/voltage (I/U ) characteristics were registered for planar asymmetric lipid bilayers composed on one side of a phospholipid mixture and on the other side of rough mutant lipopolysaccharide. This system resembles the lipid matrix of the outer membrane of Gram-negative bacteria. The evaluation of the current/voltage curves yielded a highly asymmetric electrical potential barrier. The total potential difference between the phospholipid and the lipopolysaccharide was -85 mV, a result which cannot be explained by contributions of Gouy-Chapman potentials alone. The possible contribution of dipole potentials and influences of headgroup effects are discussed. It is shown that the asymmetry of the I/U-characteristic results from the differences of the surface charge densities of the two monolayers but not from those of the states of order of their hydrocarbon chains.
Epicuticular Leaf Wax of Euphorbia helioscopia L. (Euphorbiaceae)
Authors: Nazir Muhammad , Ahmad Waqar , Rabi Naeem Akhtar , Khan Shafiq Ahmad
Published: August 2018

The epicuticular wax of Euphorbia helioscopia was fractionated into fatty acids, hydrocarbons, wax esters, aldehydes, methyl esters, triterpenol acetates, alcohols, sterols, and polar components. The composition of the fractions was determined by GC, GC-MS, HPLC. Main components within these lipid classes are hentriacontane, wax esters C46 and C48, octacosanal, hexacosanol and octacosanol, hexadecanoic acid, and β-sitosterol. Lupeol and its acetate were also confirmed.
Aromatic Amino Acids in the Venom of the Braconid Parasitoid Apanteles kariyai
Authors: Shimizu Toshiaki , Tatsuki Yoshiko , Takeda Naokuni
Published: August 2018

The venom gland of the braconid parasitoid, Apanteles kariyai, was morphologically observed with photomicroscope and aromatic amino acids in its venom fluid were chemically analyzed with a three-dimensional HPLC svstem-coulometric ECD. Tyrosine (TYR-4) → tyramine (TYRA) → hydroxyphenylacetic acid (HPAC-4) and tryptophan (TRP) → kynurenine (KYN) were the detected metabolic pathways. This report of venom components of a braconid wasp outlines qualitative differences between this and venom from social wasps.
Isoprenoid Biosynthesis and Stability in Developing Green and Achlorophyllous Leaves of Rye (Secale cereale L.)
Authors: Gölz Peter , Feierabend Jürgen
Published: August 2018

Formation of major prenylquinones and carotenoids was investigated by comparing the incorporation of [14C]mevalonate into segments of different age from green and etiolated leaves of 22 C-grown rye seedlings (Secale cereale L.) and from 32 C-grown rye leaves which contained bleached and proplastid-like ribosome-deficient plastids, due to a heat-sensitivity of 70S ribosome formation. The contents of plastidic isoprenoids were much lower (between 2 - 30%) in the achlorophyllous than in green leaves. In green leaves [14C]mevalonate incorporation into non-polar lipids and into plastoquinone was partially inhibited in the presence of gabaculin, an inhibitor of chlorophyll synthesis. However, except for β-carotene, [14C]mevalonate incorporation into isoprenoids continuously increased with age also in achlorophyllous etiolated or 32 °C-grown, as in green, leaves and was, except for P-carotene and plastoquinone, higher in etiolated than in green leaves. In bleached °32 C-grown leaves [14C]mevalonate incorporation into all plastidic isoprenoids was strikingly (up to 45-fold) higher than in green control leaves. While degradation of P-carotene was greatly enhanced in bleached 32 °C-grown leaves, relative to green control leaves, and could thus compensate for a higher apparent synthesis, chase experiments did not reveal any marked differences of the turnover of other isoprenoids. The half times of plastoquinone. phylloquinone and lutein were in the order of 2-3 days. Within a 24 h chase period a-tocopherol degradation did not become apparent. Uptake of [14C]mevalonate and [14C]isopentenyl pyrophosphate by isolated bleached plastids from 32 °C-grown leaves was much more rapid than by chloroplasts and resulted in higher precursor accumulation within the organelle. While mevalonate incorporation into isoprenoid lipids was not detected, isopentenyl pyrophosphate was incorporated into isoprenoid lipids, including plastoquinone. Rates of incorporation by isolated chloroplasts or bleached plastids were of similar order. The results illustrate that divergent types of plastid differentiation are associated with fundamental developmental changes of the metabolic flow of isoprenoid precursors between different products and compartments and, in particular, with changes of import into the plastid compartment.
Studies of Components of the Thylakoid Membrane of Undamaged and Damaged Spruce Trees at Different Mountain Sites
Authors: Wild Aloysius , Strobel Petra , Flammersfeld Ute
Published: August 2018

During a five-year period, components of the thylakoid membrane in needles of the second generation of undamaged and damaged trees of Norway spruce were studied at three different mountain sites in West Germany. Visible signs of damage at these sites are a yellowing of the light-exposed sides of the needles as well as the loss of needles. The goal of this study was to determine damage-induced alterations in composition and physiological reactions of the thylakoid membranes in spruce needles. In order to meet this purpose, contents of chlorophyll a and b, electron transport rate of photosystem II, contents of the D 1 protein, cytochrome f, as well as P-700 were measured.

The chlorophyll content in the needles of the damaged spruce trees was significantly lower than in the needles of the undamaged trees. In addition to this, the typical annual course of chlorophyll content was exclusively observed in the needles of the undamaged spruce trees. If related to dry weight, a drastic reduction of the electron transport rate and of the redox components of the thylakoid membrane was observed due to damage, indicating a degeneration of the photosynthetic membranes. The contents of D1 protein and the photosynthetic electron transport rates were also markedly reduced in the needles of the damaged trees, when related to chlorophyll content of thylakoids, suggesting an early and particular impairment of photosystem II. The comparison of spruce trees showing different signs of damage demonstrates that certain biochemical parameters concerning the photosynthetic membranes (chlorophyll, cytochrome f, ratio photosystem II/I) reflect the extent of damage and are suitable for an early indication of a beginning, but still invisible damage of spruce trees.
The Biflavones of Dicranum scoparium (Dicranaceae)
Authors: Geiger Hans , Voigt Ariane , Zinsmeister Hans-Dietmar , López-Sáez José-Antonio , Pérez-Alonso M.-José , Velasco-Negueruela Arturo
Published: August 2018

From Dicranum scoparium 5′,3‴-dihydroxyamentoflavone and 5′,3‴-dihydroxyrobustaflavone were isolated. The compounds were identified spectroscopically.
Halogenation Enhances the Photosystem II Inhibitory Activity of 4-Hydroxypyridines: Structure-Activity Relationships and Their Mode of Action
Authors: Asami Tadao , Baba Masatoshi , Koike Hiroyuki , Inoue Yorinao , Yoshida Shigeo
Published: August 2018

A range of 4-hydroxypyridines were synthesized and their activity as PET inhibitors were investigated with regard to their structural resemblance to plastoquinone in photosynthetic electron transport (PET). The activity of these compounds was markedly enhanced upon modifying their structures: introduction of halogens into both the 3-and 5-positions of the pyridine ring and additional substitution at the α-position of the side chain at 6-position were effective among others in enhancing the activity. Insertion of a phenyl ring into the side chain at 6-position of the pyridine ring also increased the activity. Substituents on the phenyl ring greatly affected the activity: when substituted with an appropriate functional group, the compounds became 10-to 100-fold more active. The mode of action of both halogenated and non-halogenated 4-hydroxypyridines were investigated by means of thermoluminescence measurements and cross resistance examination against atrazine-resistant thylakoids having mutation in D 1 protein. It was inferred that upon halogenation, 4-hydroxypyridines changed their mode of action from plastoquinone-pool inhibitors to phenol-type inhibitors.
Photosystem II Inhibition by Pyran-enamine Derivatives
Authors: Yoneyama Koichi , Nakajima Yoshihiro , Ogasawara Masaru , Kuramochi Hitoshi , Konnai Makoto , Iwamura Hajime , Sato Fumihiko , Ichinose Katsunori , Asami Tadao , Takahashi Nobutaka , Yoshida Shigeo
Published: August 2018

Through the studies on structure-activity relationships of 5-acyl-3-(1-aminoalkylidene)-4-hydroxy-2 H-pyran-2,6(3 H)-dione derivatives in photosystem II (PS II) inhibition, overall lipophilicity of the molecule was found to be a major determinant for the activity. In the substituted N -benzyl derivatives, not only the lipophilicity but also the electronic and steric characters of the substituents greatly affected the activity. Their mode of PS II inhibition seemed to be similar to that of DCMU , whereas pyran-enamine derivatives needed to be highly lipophilic to block the electron transport in thylakoid membranes, which in turn diminished the permeability through biomembranes.
Inhibition of Photosynthesis by 4-Nitro-6-alkylphenols: Structure-Activity Studies in Wild Type and Five Mutants of Chlamydomonas reinhardtii Thylakoids
Authors: Draber W. , Hilp U. , Likusa H. , Schindler M. , Trebst A.
Published: August 2018

Photosynthesis inhibition data were determined with thylakoids of the green alga Chlamydomonas reinhardtii on twenty-two 2-bromo-4-nitro-6-alkyl -and 2,4-dinitro-6-alkyl-phenols. Wild type and five different mutants of the algae were employed with defined changes in the psbA gene and a single amino acid substitution in the herbicide binding protein D 1 of photo­ system II. Their response to the various inhibitors was quite different from that of the wild type. Tolerance as well as enhanced inhibitory activity was found in the mutants, with tolerance in all phenols in the val219 ile and of some in the phe255 tyr mutant and supersensitivity of most phenols in the ala251 val, ser264 ala and leu275 phe mutant. This implies that the phenols are bound specifically to the D 1 protein. Structure-activity studies revealed parabolic relationships with all descriptors increasing with the alkyl chain length for wild type and most mutant inhibition values. Molecular modelling chains in different phenols in the QB binding niche same direction.
Significance of Photosystem II Core Phosphorylation Heterogeneity for the Herbicide-Binding Domain
Authors: Giardi Maria Teresa
Published: August 2018

In recent papers the heterogeneous nature of photosystem (PS) II core phosphorylation has been revealed (Giardi et al., BBRC 176, 1298 -1305 (1991); Plant Physiol. 100, 1948 -1954 (1992)). In this paper the action of endogenous and exogenous phosphatases both on the distribution of phosphorylated PS II core populations and on herbicide-binding activity in photosystem II preparations from Spinacia oleracea L. has been investigated. The results indicate that these phosphatases modify the photosystem II core phosphorylation heterogeneity at a different level. Dark incubation causes a partial dephosphorylation of D1 and D2 proteins by endogenous phosphatase(s) and changes the relative distribution of phosphorylated photosystem II core populations, while the action of the alkaline phosphatase leads to extensive dephosphorylation and to the detachment of PsbH protein from the photosystem II core. Dephosphorylation by the two alternative methods results in a differential modification of herbicide-binding activity. It is suggested that photosystem II heterogeneity with respect to the herbicide action, observed in vivo, could be a consequence of PS II core phosphorylation heterogeneity.
Tolerance of Cultured Amaranthus retroflexus Cells to Atrazine
Authors: Shigematsu Yoshio , Chaicharoen Sarinee , Sato Fumihiko , Yamada Yasuyuki
Published: August 2018

Resistance to s-triazine-herbicides in weeds is the most widespread and extensively studied of all intraspecific herbicide-resistance. It is of interest that the resistant biotype appears in some limited genera such as Amaranthus spp. and Chenopodium spp. much more frequently than in many other significant weeds. We examined the response of cultured Amaranthus retroflexus cells to atrazine in comparison with those of several other plant species to understand what causes this differentially inter-specific response. Atrazine scarcely inhibited the cell growth of either atrazine-resistant and susceptible-Amaranthus cells. Tobacco cells, however, could not grow as cultured Amaranthus cells in high concentrations of atrazine even under heterotrophic culture conditions. Atrazine-resistant tobacco cells were also sensitive to high concentrations of atrazine. The inhibition of cell growth by this secondary effect of atrazine was also observed in cultured wheat and rice cells. Atrazine-sensitive Chenopodium cells are relatively more resistant to high concentrations of atrazine. The importance of potential tolerance to the secondary effects of atrazine is discussed with respect to the frequent occurrence of triazine- resistant biotypes in limited plant species.
Comparative Effects of Paraquat on Antioxidant Components and Scavenging Enzymes in Kwangkyo and Hood Soybean
Authors: Kim Sangho , Hatzios Kriton K.
Published: August 2018

The effect of p araquaton hydroxyl radical production , glutathione and ascorbate content, and glutathione reductase and superoxide dismutase activities was assayed in the tolerant “Kwangkyo” and the susceptible “ Hood ” cultivars of soybean [Glycine max (L.) Merr.]. Seedlings of both cultivars at the fully expanded first trifoliate leaf stage were treated with paraquat at 0, 1, 10, 100, 500, and 1000 μᴍ. The in vivo generation of hydroxyl radicals was estimated by measuring methanesulfonic acid (MSA ) produced in soybean leaves treated with dimethylsulfoxide (DMSO ) and paraquat. The levels of paraquat-induced production of hydroxyl radicals were similar in Kwangkyo and Hood soybean. Ascorbate levels in the two cultivars were comparable and were reduced by paraquat treatment. Total glutathione levels were similar in both cultivars, but Kwangkyo had more glutathione in the reduced form than Hood. Treatment with low concentrations of paraquat enhanced oxidized glutathione levels in Hood. At high concentrations, paraquat decreased the levels of total and reduced glutathione in both cultivars. The endogenous activities of glutathione reductase and superoxide dismutase were similar in Kwangkyo and Hood soybean. Treatment with selected concentrations of paraquat enhanced the activity of these enzymes in trifoliates of the tolerant Kwangkyo. Overall, the results of this study do not suggest a strong involvement of components of the ascorbate-glutathione cycle in the observed tolerance of Kwangkyo soybean to the herbicide paraquat.
Differential Effect of Hg(II) on [d(A)n · d(T)n] and [d(A-T)n · d(A-T)n] Sequences: Circular Dichroism (CD) Measurements and Endonuclease Digestion Studies Using Poly[d(A) · d(T)] and Poly[d(A-T) · d(A-T)] as Substrates
Authors: Ok Seung Ryong , Gruenwedel Dieter W.
Published: August 2018

The long-wavelength positive CD bands of poly[d(A) · d(T)] and poly[d(A-T) · d(A-T)] become inverted upon the addition of Hg(ClO4)2. Poly[d(A) · d(T)] requires higher levels of mercury to undergo inversion than poly[d(A-T) · d(A-T)]. Mercurated poly[d(A) d(T)] is digested more rapidly than the control by DNase I or staphylococcal nuclease at low levels of Hg(ClO4)2. Let r = [Hg(ClO4)2]added/[DNA-P]. A 4- to 5-fold rate increase occurs with DNase I at r = 0.25; a 2-fold increase with staphylococcal nuclease at r = 0.2. By contrast, digestion of poly[d(A-T )· d(A-T)] decreases immediately with increasing r. The noted rate increases appear to be due to a modification of poly[d(A)-d(T)] helix structure prior to the chiroptical conversion. The modification is interpreted as a widening of the minor groove, permitting, thus, a better binding of DNase I to its substrate. The overall changes in CD as well as enzymatic digestion rates are taken to signal mercury-induced alterations in helix screwness from rightto- left. They are totally reversible subsequent to the removal of mercury.
Azadirachtin Inhibits Proliferation of Sf 9 Cells in Monolayer Culture
Authors: Rembold H. , Annadurai R.S.
Published: August 2018

Azadirachtin A in ppm quantity inhibits proliferation and monolayer formation of Spodoptera frugiperda (Sf 9) insect cells in monolayer culture. The incubated cells demonstrate reduced rates of protein synthesis which finally leads to cell death. This growth inhibiting activity is compared with other botanicals such as ohchinin, salannin and volkensin. The high and specific activity of azadirachtin A on insect cells is discussed in comparison with its effect on a mammalian cell line, based on 2D PAGE analysis of the total protein contents.