bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative Determination of the Distribution between Two Photosystem II-Mediated Oxidation Reactions in Oscillatoria chalybea: A Comparison between Water Oxidation and Hydrogen Peroxide Decomposition
Authors: Bader K. P. , Schmid G. H.
Published: August 2018

Mass spectromctric analysis reveals that oxygen evolution measured as the consequence of short saturating light flashes in thylakoid preparations of the filamentous cyanobacterium Oscillatoria chalybea consists of two portions, one coming from photosynthetic water splitting and one coming from H2O2 decomposition. This H2O2 decomposition is photosystem II-mediated and it is the S-state system which oxidizes H2O2 to give protons and oxygen. Water is neither intermediate nor seems it to be the origin of the reaction. At the high oxygen partial pressure of normal air H2O2 production and its decomposition exceeds manyfold the H2O splitting reaction. H2O2 production seems to come from photosystem II but is not necessarily produced on the acceptor side of photosystem II in the sense of a Mehler type reaction. From the reaction rate and the observed labeling density, it is inferred that production and decomposition must take place within the same reaction site which might be for both, the production and decomposition, the S-state system. In this sense. H2O2 might be the product of the S-state system and seems somehow associated with S2 or S3. Thus, if oxygen evolution is measured as the consequence of short saturating light flashes in an ambient atmosphere of 21% oxygen, mass spectrometry reveals a flash pattern which bears the oxygen label of the ambient atmosphere and which has not much in common with an usual Kok sequence. Such a pattern might start in the first three flashes more or less as a Kok pattern would, but is then in the pattern portion usually characteristic for steady-state oxygen evolution characterized by a periodicity of two indicating that H2O2 decomposition requires only two light quanta. At high oxygen partial pressure (e.g. in 21% ,16O2) both reaction portions can be quantitatively deter- mined by labeling the assay with H2
18O and measuring the evolved (16O::18O)/18O2 ratio which is representative for water splitting. The measured evolution of 16O2 (mass 32) represents H2O2 decomposition, if the 16O2 portion calculated from the measured mass 34/36 ratio is subtracted. At low oxygen partial pressure the H2O2 forming and decomposing reaction is largely sup- pressed and oxygen evolution from water-splitting prevails. As a hypothesis, H2O2 production and its decomposition might be a defective performance of photosystem II at high ambient oxygen partial pressure in these cyanobacteria, perhaps due to the principal absence of two of the extrinsic peptides from photosystem II.
Sex Pheromones in Nereids: Volatile Compounds of the Coelomic Fluid of Nereis virens
Authors: Zeeck E. , Hardege J. D.
Published: August 2018

Volatile compounds of the pheromone bouquet of Nereis virens have been isolated and identified from the coelomic fluid of ripe sub-heteronereids. One of the minor compounds is the sex pheromone of Platynereis dumerilii, 5-methyl-3-heptanone.
A Further Contribution to the Triterpenoid Constituents of Glycyrrhiza glabra L
Authors: Elgamal M. H. A. , Hady F. K. Abdel , Hanna A. G. , Mahran G. H. , Duddeck H.
Published: August 2018

Pentacyclic Triterpenoids, G lycyrrhiza glabra, 1H and 13C Chemical Shifts Five pentacyclic triterpenoids have been isolated from the minor constituents of local liquorice roots, one of them (8) has not been isolated before from liquorice root. Their struc­ tural formulae and stereochemical configuration was determined by spectroscopic methods. 13C and 1H NMR data have been compiled.
Further Studies on the Biosynthesis of Pseudoisoeugenols in Tissue Cultures of Pimpinella anisum
Authors: Reichling Jürgen , Martin Rainer
Published: August 2018

Tissue cultures of Pimpinella anisum and P. major were used to study the biosynthesis of pseudoisoeugenols. The putative precursors were labelled with 13C with one exception that was labelled with 14C. The incorporation of the label was controlled by 13CNMR and liquid scintil­ lation, respectively. The biosynthetic sequence found was L-phenylalanine, p-cinnamic acid, p-coumaric acid, p-hydroxycoum aric alcohol, p-methoxycoumaric alcohol and anethol. The incorporation rates ranged from 0.5% to 25%.
Defence Reactions in Rhizobium-Legume Symbiosis: Phytoalexin Concentration in Vicia faba Nodules is Affected by the Host Plant Genotype
Authors: Wolff Andreas B. , Werner Dietrich
Published: August 2018

In the Vicia faba-Rhizobium leguminosarum symbiosis defence reactions are established by a variable phytoalexin concentration in the nodules. No differences were observed between effective (fix+) and ineffective (fix- ) nodules. In nodules of field grown plants the average phytoalexin concentration was about 3 times higher than that from sterile pot-cultured plants infected with different Rhizobium leguminosarum strains. A great variability of phytoalexin accumulation in nodules of single plants was observed. In field grown plants about 60% of the nodules of each plant had very low levels (< 50 µg wyerone g nodule fresh weight-1) the other 40% had levels between 100 and 600 µig w yerone-g nodule fresh weight-1 indicating different defence reactions in the nodules distributed over the root system of one plant. Phytoalexin accumulation was more affected by the cultivar of the host plant than by the infecting Rhizobium strain. Two inbred lines had the lowest concentration in nodules
3 ß-Hydroxysteroid Oxidoreductase in Suspension Cultures of Digitalis lanata EH RH
Authors: Warneck Hildegard Maria , Seitz Hanns Ulrich
Published: August 2018

A 3 β-hydroxysteroid oxidoreductase was isolated and characterized in the microsomes of Digitalis lanata cell cultures. The enzyme catalyzes the conversion of 5α-pregnane-3,20-dione to 5a-pregnan-3 β-ol-20-one and requires NAD(P)H2. The enzyme was found to have a pH optimum of 80. The reaction had an optimum incubation temperature of 25 °C with linear reduction for the first 4 h, reaching maximum enzyme activity after 7 h. Substrate kinetics for 5a-pregnane-3,20-dione and NADPH2 resulted in apparent Km-values of 18.5-20 (µM for 5a-pregnane-3,20-dione and 50-120 µM for the co-substrate NADPH2. In order to localize 3β-hydroxysteroid oxidoreductase differential centrifugation as well as linear sucrose density gradient centrifugation were performed. The results obtained lead to the conclusion that 3β-hydroxysteroid oxidoreductase is not associated with a single cell compartment, but consists of a major soluble part and a markedly smaller part of endoplasmic reticulum-associated activity
Two Forms of Herbicide-Sensitive Acetolactate Synthase under Different Control by 2-Oxobutyrate in Rhodospivillum rubrum
Authors: Klemme Jobst-Heinrich , Schneider Irmgard
Published: August 2018

Regulation of acetolactate synthase (ALS, EC 4.1.3.18) in the phototrophic prokaryote Rhodospirillum rubrum was studied. In cell free extracts of 5 strains investigated, enzyme activity was very labile (about 80% loss of activity within 12h during storage at 4 °C) but was stabilized to some extent by 10 (μM FAD and 20 vol.% glycerol. By filtration of extracts through Superose 6 HR gels (FPLC technique), ALS activity of all strains was separated in two fractions of 200 and 600 kDa, respectively. The enzyme fractions had about the same affinity to pyruvate (ATm = 1.6 - 1.8 m M) , the same sensitivity to L-valine (50 and 65% inhibition by 0.1 m M valine in the standard test mixture) and the herbicide sulfometuron methyl (90 and 92% inhibition by 1 μM herbicide), but differed greatly in their sensitivity to inhibition by 0.4 m NaCl. In culture media with 2-oxobutyrate (2-OB), growth began only after a lag-phase of several days (5 days with 1 mM of the inhibitor). Cells grown in the presence of 2-OB had a reduced total ALS activity and did not contain the 200 kDa fraction. The inhibition of ALS by valine was noncompetitive in respect to pyruvate (K1= 0.l m M ) . From other branched-chain amino acids tested (L-leucine, L-isoleucine, norvaline, norleucine) only isoleucine was inhibitory (K1; = 3.1 m M )
Thermal Behaviour of Lymphocyte Membrane: ESR Investigation
Authors: Mazzuca S. , Sportelli L.
Published: August 2018

The order parameter, S, of the plasma membrane of in toto human peripheral blood lym­ phocytes was obtained by electron spin resonance spectroscopy in the temperature range 25-41°C. This membrane is completely in the liquid crystalline state above 31 °C. In presence of the antigen ETB from Staphylococcus aureus at the concentration of 4 μ/3 × 107 cells an overall decrease of the order parameter for this membrane is observed.

The decrease of 5 is followed by an upwards shift at about 35 °C of the temperature of the liquid crystalline state.
On the Propeller Structure of Isolated Watson-Crick Base Pairs
Authors: Komarov V. M. , Polozov R. V.
Published: August 2018

We consider the strongly nonplanar hydrogen bond­ ing of nitrous bases in single Watson-Crick pairs to be due to pyramidal structure of their NH,-groups. 1080
X-Ray Structure Analysis of a Cyanoacrylate Inhibitor of Photosystem II Electron Transport
Authors: McFadden Helen G. , Craig Donald C. , Huppatz John L. , Phillips John N.
Published: August 2018

X-ray crystallographic data for the highly potent cyanoacrylate photosynthetic electron transport inhibitor, (Z)-ethoxyethyl 3-(4-chlorobenzylamino)-2-cyano-4-methylpent-2-enoate, are presented. This compound has a particularly high affinity for the photosystem II (PS II) herbicide receptor with a p I50 value of 9.5 (in the Hill reaction under uncoupled condi­tions with a chlorophyll concentration of 0.1 μg/ml). Data regarding the structure of small li­gands, such as this potent cyanoacrylate, which bind to the site with high affinity may be used to provide the basis for modelling studies of PS II/herbicide complexes. The X-ray data presented confirm the Z-stereochemistry of active cyanoacrylates and demonstrate the pres­ence of a planar core stabilized by an intramolecular hydrogen bond between the ester car­bonyl oxygen and a benzylamino hydrogen atom. In order to assess the importance of the benzylamino -NH -group in this type of cyanoacrylate, analogues containing a methylene group in its place were synthesized and found to be 100-and 1000-fold less active as Hill inhibitors.
X-Ray Studies on Phospholipid Bilayers. X. Interactions with Chlortetracycline Hydrochloride
Authors: Suwalsky M. , Neira F.
Published: August 2018

This study deals with the structural perturbations that the antibiotic chlortetracycline hy­drochloride (CTC) can produce on phospholipid bilayers. Two multibilayer systems, one built-up of dimyristoylphosphatidylethanolamine (DMPE) and the other of dimyristoylphos-phatidylcholine (DMPC) were allowed to interact with different concentrations of CTC in the absence and presence of water. The study was carried out by X-ray diffraction methods and all experiments were done below the phospholipid main transition temperatures. The results showed that CTC produced significant perturbations on DMPC even in the absence of water, whereas they were much milder in DMPE .
Safeners as Corn Seedling Protectants against Acetolactate Synthase Inhibitors
Authors: Milhomme Henri , Roux Christophe , Bastide Jean
Published: August 2018

Zea mays L., cv. Potro, shoots had a higher level of resistance to imazaquin (IQ) and metsulfuron methyl (M SM ) than roots. Shoot lengths were increased by pretreating the seeds with commercial 1,8 -naphthalic anhydride (N A ) at 1% (w/w) or oxabetrinil at 0.2% (w/w). The growth of shoots of safened seeds was unaffected by 400 nM IQ and by 40 nM MSM. The in vivo activity of acetolactate synthase (ALS) extracted from corn shoots and roots was not affected by treatments with IQ or MSM, but pretreatment of seeds with NA or oxabetrinil, prior to germination, caused an increase in the level of extractable ALS from shoots. ALS activity from roots and shoots of NA-pretreated seedlings was increased to a large degree (> 40% ) when the seedlings were germinated on 40 nM MSM, whereas ALS activities from oxabetrinil-pretreated seedlings were enhanced to a lesser degree (≈20%). ALS from unsafened seedlings was inhibited 21% by 400 nM IQ and 70% by 40 nM MSM in vitro, but ALS from roots of seedlings germinated on 400 nM IQ was not inhibited by 400 nM IQ in

vitro.
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.
Antagonism by Clopyralid of Picloram-Induced Ethylene Biosynthesis in Rapeseed Plants
Authors: Hall J. Christopher , Soni Mira
Published: August 2018

The effect of clopyralid pretreatment (500 g/ha) on picloram-induced ethylene, ACC (1-aminocyclopropane-l-carboxylic acid), and MACC [l-(malonylamino)-cyclopropane-1-carboxylic acid] was measured in rapeseed plants that were treated with 50 or 100 g/ha of picloram. In contrast to plants that did not receive a clopyralid pretreatment, ethylene biosynthesis was significantly reduced in plants pretreated with clopyralid prior to picloram. Picloram- induced levels of ACC also were significantly reduced in plants receiving pretreatment with clopyralid. In contrast, there was no difference between the levels of MACC in plants that were and were not pretreated with clopyralid. Therefore, the mechanism by which clopyralid pretreatment interferes with picloram-induced synthesis of both ACC and ethylene may be manifested through the blocking of de novo synthesis of ACC synthase normally stimulated by picloram. The lack of significant difference in MACC levels between plants that were and were not pretreated with clopyralid precludes the stimulation of enhanced ACC conversion to MACC as an exclusive mechanism of clopyralid’s antidoting activity. It is likely that the rate of picloram-induced ACC synthesis by plants receiving pretreatment is within their capacity to convert ACC to MACC, thereby limiting the substrate available for conversion to ethylene. In contrast, it appears that the extent of ACC synthesis by plants receiving no pretreatment supersedes their capacity for conversion to MACC. thereby resulting in greatly enhanced rates of ethylene evolution and subsequent development of injury symptoms.
Replikation ColE 1-verwandter Plasmide bei erhöhter Wachstumstemperatur in Abhängigkeit von der Rom-Funktion / Replication of ColE 1-Related Plasmids at Increased Growth Temperature in Dependence on the Rom Function
Authors: Riethdorf Sabine , Ulrich Andreas , Hecker Michael
Published: August 2018

The content of ColE 1-related plasmids increased about 4-6-fold after a temperature-shift from 30 to 42 °C (45 °C) if the rom-region of the plasmids was deleted.

The copy number of rom+-plasmids did not change after the temperature shift. All rom¯-plasmids tested in this study showed this plasmid amplification. The Rom-protein is capable of inhibiting plasmid replication by stabilization the initial reversible stage of the association of RNAI with the primer precursor RNAII.

We suggest that the temperature-dependent enhancement of the copy number of rom¯-plasmids is due to a destabilization of this initial phase of the RNAI-preprimer interaction at high temperatures which is suppressed by the Rom-protein in cells with rom+-plasmids.
Studies on Uroporphyrinogen Biosynthesis in Pig Liver
Authors: Fumagalli Silvia A. , Kotier Monica L. , Rossetti María V. , del C. Batlle Alcira M.
Published: August 2018

Porphobilinogen-deaminase (PBG-D) and PBG-D-isomerase complex (PBG-D-I) from pig liver were isolated and partially purified. Uroporphyrinogen I and III formation was found to be linear with time and protein concentration. Optimal pH was about 7.4 and 7.6-7.8 for PBG-D and PBG-D-I complex, respectively.

Some properties of the isolated enzymes were studied. Molecular mass determination gave a value of 40,000 Da for PBG-D and 50,000 Da for the complex. Both enzymes exhibited classical Michaelis-Menten kinetics. Km and Fmax parameters were estimated. The effect of several divalent cations, ammonia and thiol reagents was also investigated. The differential action of some of these chemicals on PBG-D and PBG-D-I system would suggest that PBG-D and isomerase may not be only physically adjacent but actually associated.
Die Bildung hydroxylierter Phenazine durch Pseudomonas fluorescens Y4 bei Be2+-Zusatz zum Kulturmedium – ein Abwehrmechanismus? [1] / The Form ation of Hydroxylated Phenazines by Pseudomonas fluorescens Y4 upon Addition of Be2+ to the Culture Medium – a Defense Mechanism?
Authors: Taraz K. , Schaffner E. M. , Budzikiewicz H. , Korth H. , Pulverer G.
Published: August 2018

Pseudomonas fluorescens Y4 grown in an iron deficient medium produces increased amounts of 2,9-di- and 2,3,9-trihydroxyphenazine-1-carboxylic acid when Be2+ is added to the culture. The significance of the formation of these compounds is discussed.
The Expression of a Third Nitrogenase in the Cyanobacterium Anabaena variabilis
Authors: Kentemich T. , Haverkamp G. , Bothe H.
Published: August 2018

Physiological experiments indicate that Anabaena variabilis can express either a V- or a Fe-nitrogenase in addition to the conventional, M o-containing enzyme complex. The occurrence of the Fe-nitrogenase in A. variabilis can also be concluded from DNA - DNA hybridization experiments using cloned anfW or nifW probes coding for the smaller subunit (= nitrogenase reductase) of the Fe-nitrogenase from Azotobacter vinelandii or for the same subunit of the Mo-nitrogenase from Klebsiella pneumoniae. The cyanobacterium A. variabilis is the first phototroph found to contain all three nitrogenases wich has been described only for A. vinelandii as yet. Vanadium cannot substitute for Mo in nitrate reduction of A. variabilis.
On the Relationships between the Genetic Code Coevolution Hypothesis and the Physicochemical Hypothesis
Authors: Di Giulio Massimo
Published: August 2018

This paper analyzes the relationships between the genetic code coevolution hypothesis and the physicochemical hypothesis by means of a comparative study of the precursor-product amino acid pairs on which the former hypothesis is based. Even if the coevolution between the biosynthetic relationships of amino acids and the organization of the genetic code is not questioned in this paper, the results and the arguments used lead us to believe that the selective pressures considered essential by the physicochemical postulates, played a more active role than that of the precursor-product relationships in defining the allocation of these amino acids in the genetic code. It is furthermore pointed out that the two evolutionary hypothesis might be aspects of the same selective pressure, and thus difficult to differentiate.
Highly Oxygenated Bisabolanoids In Rosa Rugosa Leaves
Authors: Hashidoko Yasuyuki , Tahara Satoshi , Iwaya Noriko , Mizutani Junya
Published: August 2018

Five novel bisabolane sesquiterpenes possessing a tetrahydrofuran ring or a hydroperoxy group were isolated from Rosa rugosa leaves and their structures elucidated by chemical and spectroscopic methods. These highly oxidized sesquiterpenes were structurally related to bisaborosaol A which is the major bisabolanoid of the plant
The Effect Of Activated Oxygen Species On Nitrogenase Of Anabaena Variabilis
Authors: Bagchi Suvendra N. , Ernst Anneliese , Böger Peter
Published: August 2018

The heterocyst-forming cyanobacterium Anabaena variabilis (ATCC 29413) is deficient in catalase activity, but especially heterocysts are rich in superoxide dismutase and peroxidases. It exhibits a light-dependent methylviologen-catalyzed oxygen uptake which is accompanied by a massive release of hydrogen peroxide. Methylviologen caused a transient concentrationdependent inhibition of nitrogenase ending in a complete loss of activity. Suppression of hydrogen peroxide accumulation by the photosynthesis inhibitor D C M U (diuron, 3-[3,4-dichlorophenyl]- 1, 1-dimethylurea), or by addition of catalase prevented nitrogenase inhibition indicating that methylviologen affects nitrogenase activity via hydrogen peroxide produced by photosynthetic electron transport. Immunospecific Western blotting of cell extracts separated on SDS polyacrylamide gel electrophoresis showed that the transient inhibition of nitrogenase is accompanied by rapid modification of its Fe-protein followed by enzyme destruction. In a cell-free system the enzyme exhibited only moderate sensitivity towards hydrogen peroxide but was found susceptible against activated oxygen species generated by the xanthine/xanthine oxidase system and free iron. The results indicate that H2O2: itself has little direct effect on nitrogenase, but endogenous peroxide produced by methylviologen in the light may initiate oxygen radical formation leading to nitrogenase modification and subsequently its destruction
Photophysical and Photochemical Properties of 2,3-Dihydro-4(l H)- quinolinones. Part II. Rates and Mechanism of Primary Processes
Authors: Bakalova Sn. , Biczók L. , Bérces T.
Published: August 2018

Fluorescence quantum yields, singlet lifetimes and triplet yields for 2-methyl-2,3-dihydro-4(1 H)-quinolinone and N -m ethyl-2,3-dihydro-4(1 H)-quinolinone were determined as a function of temperature. In non-polar solvents, an efficient non-radiative process identified as an indirect singlet →triplet transition occurring through S2(n,π*) was found to depopulate the lowest S1(π,π*) state. In polar solvents, direct singlet → triplet intersystem crossing appears to dominate.

Photochemical dehydrogenation produced the corresponding 4(1 H)-quinolinone with a yield of few times 10-2. This was shown to be the only traceable reaction route.
Induction of Nitrate Reductase Activity by Arginine in the Filamentous Cyanobacterium Oscillatoria chalybea
Authors: Bednarz J. , Schmid G. H.
Published: August 2018

Abstract In Oscillatoria chalybea, as in other cyanobacteria, nitrate reduction depends directly on photosynthetic activity. Hence, nitrate reduction occurs only in the light and appears inhibited when photosynthesis is inhibited by the herbicide DCMU . Growth of Oscillatoria cells is possible on a variety of exogenous nitrogen sources in the medium and appears largely independent on the type of nitrogen source. However, if citrulline is the exogenous nitrogen source or if no exogenous nitrogen source is given in the medium, growth appears almost fully inhibited. Nitrate reductase activity measured in French-press particles of nitrate-grown cells is depend­ent on the age of the culture with maximum nitrate reductase activity being reached on the 5th day. Thereafter activity decreases steeply to less than 20% of the maximal activity within 10 days. Besides the growth stage it is the type of exogenous nitrogen source used in the medium which is important for the development of nitrate reductase activity. It appears that in the presence of nitrate, nitrite and arginine, nitrate reductase activity is induced whereas in the presence of ammonia or amino acids like alanine nitrate reductase activity is not induced, as already reported in the literature. Nitrate reductase is also induced if arginine and ammonia are simultaneously offered as exogenous nitrogen source. Arginine metabolism in Oscillatoria cells is characterized by the fact that thylakoid preparations of Oscillatoria catalyze the trans­ formation of arginine to give ornithine and ammonium. The arginine-metabolizing enzyme differs from the usual arginine-induced arginase. The enzyme seems to be constitutive, not manganese-dependent, exhibiting an approximately 5 times higher substrate affinity to arginine than the known arginase. In the present paper we propose that in Oscillatoria it is arginine which induces the synthesis of nitrate reductase.
Mass Spectrometric Analysis of N2-Formation Induced by the Oxidation of Hydrazine and Hydroxylamine in Flash Illuminated Thylakoid Preparations of the Filamentous Cyanobacterium Oscillatoria chalybea
Authors: He P. , Bader K. P. , Schmid G . H.
Published: August 2018

In tobacco chloroplasts hydrazine-dependent dinitrogen formation measured by mass spectrometry as the consequence of short saturating light flashes is always linked to a substantial oxygen uptake (G. Renger, K. P. Bader, and G. H. Schmid, Biochim. Biophys. Acta 1015, 288, 1990). However, in thylakoids of the filamentous cyanobacterium Oscillatoria chalybea this dinitrogen formation is not linked to an apparent O2-uptake, even at the high concentration of 1 mм hydrazine. Whereas in tobacco chloroplasts Tris-treatment does not affect hydrazine dependent dinitrogen formation up to a concentration of 3 mм hydrazine, Tris-treatment of thylakoids of O. chalybea affects strongly both oxygen evolution and dinitrogen evolution under a single turnover flash as well as under ten flashes. In contrast to tobacco chloroplasts, the presence of hydrazine up to concentrations of 3 mм does not substantially affect photosynthetic O2-evolution. The observed dinitrogen evolution is affected by DCMU regardless whether induced by a single turnover flash or by ten flashes, whereas in tobacco dinitrogen evolution and the O2-uptake linked to it (which is not observed in the cyanobacterium) were clearly not affected by DCMU in the single turnover flash. In Oscillatoria the earlier described Photosystem II-mediated H2O2 formation and decomposition is influenced by hydrazine. In the presence of 300 μм hydrazine the usually present O2-uptake leading to H2O2 formation appears diminished.
X-Ray Studies on Phospholipid Bilayers. XI. Interactions with Chloramphenicol
Authors: Suwalsky M. , Espinoza M. A. , Sánchez I. , Villena F.
Published: August 2018

Chloramphenicol is a widely used antibiotic with low levels of toxicity. However, scanning electron microscopy revealed morphological changes in human erythrocytes when they interacted in vitro with therapeutical concentrations of chloram phenicol. To explain this shape change, a study concerned with the possible interactions of this antibiotic with bilayers built-up of phospholipids located in either side of the red cell membrane was performed by X-ray diffraction. Results indicated that chloramphenicol was unable to perturb in any significant extent the structure of the phospholipids under study. The only noticeable effects were phase transitions produced to dim yristoylphosphatidylethanolamine bilayers.
Cyclic Glycerol Acetals from the Abdominal Hair Pencil Secretion of the Male African Sugarcane Borer Eldana saccharina (Lepidoptera: Pyralidae)
Authors: Burger B. V. , Nell A. E. , Smit D. , Spies H. S. C.
Published: August 2018

Four constituents of the hair pencil secretion of the male African sugarcane stalk borer, Eldana saccharina, having a molecular mass of 312 and peculiar El mass spectra with an exceptionally abundant base peak at m /z 103, were isolated preparatively from an extract of the secretion. Using 1H and 13C NMR spectral analysis, these constituents were identified as fiveand six-membered cyclic glycerol acetals of Z-9-hexadecenal, viz. cis- and trans-2-(Z- 8-pentadecenyl)-4-hydroxymethyl-1,3-dioxolane, and cis- and trans-2-(Z-8-pentadecenyl)- 5-hydroxy-1,3-dioxane. These compounds are related to the 2-alkenyl-4-hydroxymethyl-1,3- dioxolane dihydrogen phosphate esters, known to be the active constituents of the smooth muscle contracting acidic phospholipid (Darmstoff) which was isolated from the intestine of mammals. The presence of these acetals in the tail brush secretion of E. saccharina could possibly be the first evidence that com pounds related to the active principle of Darmstoff, may also be present in the insect kingdom. The possibility that these four compounds or their dihydrogen phosphate esters might play a part in the eversion or retraction of the tail brushes of the male insect, is briefly discussed.
Effects of Culture Conditions on Isoflavonoid Levels of Transformed and Non-Transformed Cultures of Lupinus -a Comparison of Suspension and Hairy Root Cultures
Authors: Berlin J. , Rügenhagen C. , Rippert M. , Erdogan S.
Published: August 2018

Some highly productive suspension and hairy root cultures were found among several trans­formed cultures of Lupinus polyphyllus and L. hartwegii. A transformed suspension culture Lupo 30150 and a root culture Luha 15834 containing the highest specific isoflavone glucoside content were characterized and compared with normal phytohormone-dependent lines with respect to product stability as well as to their responsiveness to external triggers, e.g. response to changes in the medium. While phytohormone-dependent suspension cultures lost their ini­tial ability to form increased levels of isoflavonoids on phytohormone-free medium, the trans­formed phytohorm one-independent suspension Lupo 30150 remained a highly productive line, despite the fact that its specific levels decreased to 60% of the initial values during several years in liquid medium. Highest stability of product patterns and levels were noted for the transformed root culture. Phytohorm ones had little effect on growth and isoflavonoid levels in suspension cultures, while they reduced both strongly in root cultures. In the presence of 2,4-D the root culture changed into an aggregated low producing suspension culture from which the root state was recovered on phytohorm one-free medium. As long as the root state was main­ tained, isoflavonoid levels could not be distinctly improved by media variation while specific isoflavonoid levels of suspensions were increased by stress factors such as phosphate depletion. When suspensions were transferred to fresh medium phenylalanine ammonia-lyase was greatly induced within 24 h, while the activity remained nearly unchanged in root cultures.
Are Bacterial Sensory Systems Models for Phytochrome Action? Hydrophobic Cluster Analysis of the Phytochrome Module Related to Bacterial Transmitter Modules
Authors: Schneider-Poetsch Hansjörg A. W. , Sensen Christoph , Hanelt Sabine
Published: August 2018

C-terminal amino acid sequences of two phytochromes sharing less than 40 per cent homol­ogy and two transmitter modules of bacterial sensor proteins that share homologies with phy­tochromes were examined by hydrophobic cluster analysis. Striking coincidences in distribu­tion, size, shape and orientation of hydrophobic and hydrophilic domains of the bacterial transmitter modules and phytochrome sequences were revealed. The results corroborate the view that the folding of the homologous regions of the two groups of proteins is similar. Since the mode of action of phytochrome is not known, the structural coincidences may be indica­tive of how phytochrome transmits signals, although distinct differences should not be over­ looked. Some coinciding structural features in phytochromes and bacterial sensors may tenta­tively be extracted from secondary structure predictions.
Subunit δ of Chloroplast F0F1 ATPase and OSCP of Mitochondrial F0F1 ATPase: a Comparison by CD-Spectroscopy
Authors: Engelbrecht Siegfried , Reed Jennifer , Penin François , Gautheron Danièle C. , Junge Wolfgang
Published: August 2018

CD spectra have been recorded with subunit δ from chloroplast CF0CF1 and with OSCP from mitochondrial MF0MF1. These subunits are supposed to act similarly at the interface between proton transport through the F0-portion and ATP-synthesis in the F1-portion of their respective F0F1-ATPase. Evaluation of the data for both proteins revealed a very high α-helix content of -85% and practically no β-sheets. Despite their low homology on the primary structure level (23% identity) and their different electrostatic properties (pl-values differ by 3 units), spinach δ and porcine OSCP are indistinguishable with respect to their secondary structure as measured by CD. Prediction and analysis of consensual a-helices even in poorly conserved regions indicate α high degree of structural similarity between chloroplast δ and OSCP. In view of the topology and function of δ and OSCP in intact F0F1 these findings are interpreted to indicate the dominance of secondary and tertiary structure over the primary structure in their supposed function between proton flow and ATP-synthesis.
Inhibition of Oxygen Evolution by Cacalol and Its Derivatives
Authors: Lotina-Hennsen B. , Roque-Reséndiz J. L. , Jiménez M. , Aguilar M.
Published: August 2018

The inhibition of ATP synthesis, proton uptake and electron transport (basal, phosphory-lating and uncoupled) from water to methylviologen indicates that cacalol and its derivatives act as electron transport inhibitors. Since on one hand photosystem I is not affected and elec­tron transport from DPC to QA is midly affected and on the other hand the electron transport from water to DCIP, and water to silicomolibdate are inhibited, we conclude that the site of inhibition of cacalol is located at the oxygen evolution level. Cacalol derivatives inhibit elec­tron flow between P680 to QA and probably also the QB site.
N-Acetyl-ß-ᴅ-hexosaminidases of the Brine Shrimp Artemia: Partial Purification and Characterization
Authors: Spindler Klaus-Dieter , Funke-Höpfner Brigitte
Published: August 2018

N-Acetyl-β-ᴅ-hexosaminidases (EC 3.2.1.52) from Artemia nauplii were isolated and char­acterized. Three different enzymes I, II1 and II2 were separated according to their behaviour on anion exchange chromatography and gel filtration columns. Their apparent molecular masses were 83,000 ± 7000, 110,000 ± 10,000 and 56,000 ± 5000 Da with corresponding S-values of 8.6, 11.9 and 7.9. All three enzymes also differ in their apparent pH-optima (5.1, 4.5 and 6.1) and they all bind to concanavalin A.

The three enzymes have about the same affinities (app. Km between 0.16 and 0.72 mmol/1) for the three substrates (p-nitrophenyl-N-acetyl-β-ᴅ-glucosamine or p-nitrophenyl-N-acetyl-β-ᴅ-galactosamine and N ,N′-diacetyl-chitobiose) and are therefore N-acetyl-β-ᴅ-hexosaminidases. In contrast, the three enzymes behave quite differently, both in terms of their inhibitor constants and the type of inhibition. The substrates inhibit both enzymes II1 and II2 but not enzyme I. On the other hand, N-acetyl-β-ᴅ-galactosamine inhibits enzyme I in a non-competi­tive way but not enzymes II1 and II2. All three enzymes are inhibited by the end product N-acetyl-β-ᴅ-glucosamine, enzyme I in a competitive manner, both enzymes II1 and II2 in a non-competitive way. 2-Acetamido-2-deoxy-ᴅ-galactonolactone is a strong inhibitor for en­zyme I (Ki = 13 μtmol/l) with much lower affinities towards enzymes II1 and II2 (Ki = 0.63 and 1.03 mmol/l). All three enzymes are inhibited in a dose-dependent way and completely reversi­ble by α-methyl-mannoside.
The Effect of BAS 145138 Safener on Chlorimuron Ethyl Metabolism and Toxicity in Corn
Authors: Lamoureux Gerald L. , Rusness Donald G.
Published: August 2018

BAS 145138 was moderately effective in protecting corn from injury due to chlorimuron ethyl. BAS 145138 increased the I50 of chlorimuron ethyl to corn, determined by root-growth in a sandy loam soil, from 6 g chlorimuron ethyl/ha to 25 g/ha. BAS 145138 caused an increase in the rate of chlorimuron ethyl metabolism , but it did not effect the rate of chlorimuron ethyl uptake or the nature of the metabolites produced. Major metabolites included chlorimuron ethyl hydroxylated in the pyrimidine ring (hydroxychlorimuron ethyl), the glucoside of hydroxychlorimuron ethyl, the glutathione conjugate formed by displacement of chlorine, a metabolite characterized as the glutathione conjugate sulfoxide or a hydroxylated glutathione conjugate, four unidentified polar metabolites, and 2-sulfonylamino benzoic acid ethyl ester. Metabolites were characterized by mass spectrometry and hydrolysis. It was concluded that BAS 145138 partially protects corn from chlorimuron ethyl by causing an increase in the rate of herbicide metabolism by hydroxylation, glucoside conjugation and by glutathione conjugation.
Influence of BAS-145138 on the Activity of Sulfonylurea and Imidazolinone Herbicides
Authors: Devlin Robert M. , Zbiec Irena I.
Published: August 2018

This study demonstrates that corn can be partially safened by BAS-145138 against sulfonyl­urea and imidazolinone herbicides. The corn seeds were impregnated with BAS-145138 by soaking the seeds for 6 h in solutions of the safener. BAS-145138 had no effect on corn growth. However, corn shoot and root growth in length, fresh weight, and dry weight was partially protected by BAS-145138 from the phytotoxic effects of the sulfonylurea herbicides thiametu­ron and CGA -136872. Similar protection was given to corn against the phytotoxic activity of the imidazolinone herbicides imazapyr, imazaquin, and imazethapyr. This study suggests that corn could be safened with BAS-145138 against the phytotoxic effects of residual amounts of sulfonylurea and imidazolinone herbicides found in rotations take place.
7-Desmethyl-Microcystin-RR, a Hepatotoxin from a Waterbloom of Microcystis aeruginosa
Authors: Martin Cornel , Weckesser Jürgen , Ino Tomio , König Wilfried A. , Skulberg Olav M.
Published: August 2018

A peptide toxin was isolated from a waterbloom of Microcystis aeruginosa from Lake Froylandsvatn in Norway. The isolation procedure included liquid and solid phase extraction and reversed phase high performance liquid chromatography. Amino acid analysis yielded ᴅ-glutamic acid, ᴅ-erythro-β-methylaspartic acid and ᴅ-alanine in equimolar and ʟ-arginine in twofold molar ratios. The presence of dehydroalanine was confirmed by hydrogenation and subsequent amino acid analysis with combined gas liquid chromatography/mass spectrometry. Investigation of the toxin with fast atom bombardment mass spectrometry showed a nominal relative molecular mass of 1023. 3-Amino-9-m ethoxy-2,6,8-trimethyl-10-phenyl-4,6-decadienoic acid (Adda) was identified by 1H NMR and 1H, 1H COSY spectroscopy. The structure of the toxin was elucidated as 7-desmethyl-microcystin-RR.
Inhibition of de novo Fatty-Acid Biosynthesis in Isolated Chloroplasts by the Antibiotic Cerulenin and Its Synthetic Derivatives
Authors: List Bernd , Golz Andrea , Boland Wilhelm , Lichtenthaler Hartmut K.
Published: August 2018

The antibiotic cerulenin was shown to be a potent dose-dependent inhibitor of de novo fattyacid biosynthesis in intact isolated chloroplasts of different plants (measured as [14C]acetate incorporation into the total fatty-acid fraction). Various chemical derivatives of cerulenin were synthesized and tested in the chloroplast assay-system of oat, spinach and pea. Modifications of the hydrocarbon chain of cerulenin (e.g. tetrahydro-cerulenin and its short-chain cis-2,3-epoxy-4-oxoheptanamide derivative) decreased the inhibitory activity of cerulenin, whereas variations of the epoxy-oxo-amide structural element led to a complete loss of inhibition potency. The results indicate that the naturally occurring antibiotic cerulenin is the most active specific inhibitor of de novo fatty-acid biosynthesis, but the formation of the hydroxylactam ring seems to be an essential requirement for the inhibitory activity. Those structural analogues of cerulenin, which can no longer form a hydroxylactam ring, do not possess any inhibitory capacity.
Response of Liverwort Cells to Peroxidizing Herbicides
Authors: Iwata Shuji , Nakayama Naoko , Nakagawara Shunji , Ohta Yoshimoto , Tanaka Takaharu , Wakabayashi Ko , Böger Peter
Published: August 2018

Cell suspension cultures of the liverwort, Marchantia polymorpha L. were found useful to study the influence of peroxidizing herbicides either on the greening process or on the fully green cells. The cells of both physiological stages exhibit a characteristic sensitivity to the herbicides. The sensitivity increased rapidly during the exponential phase of growth, reached a maximum during the late exponential phase, and then decreased in the stationary phase.

We investigated the kinetics of accumulation of protoporphyrin IX (PPIX) in Marchantia cells treated with several peroxidizing herbicides at various stages of cell growth, and observed a correlation between accumulation of PPIX and herbicidal damage.

The glutathione (GSH) content in the cell was also investigated to examine the role of GSH against herbicide treatment. In the light, GSH levels in the cells treated with AFM rose rapidly reaching a peak after 8 h, and rapidly decreased subsequently. The beginning of PPIX accumulation coincided with the decline of GSH after 8 h of treatment. Obviously, GSH plays a key role in protection against oxidative damage caused by AFM in the early treatment period. In the dark, AFM also induced an accumulation of GSH and PPIX, followed by a decline in GSH and PPIX contents during a 20 h incubation. The decline of PPIX was observed several hours after GSH starts to decrease, remaining at a constant level for the following 40 h, leading to accumulation of an other fluorescent still-unknown pigment.
Notes: Analysis of Phenolics of Bud Exudates of Populus simonii and Populus yunnanensis by GC-MS
Authors: Greenaway W. , May J. , Scaysbrook T. , Whatley F. R.
Published: August 2018

Bud exudates of Populus simonii and Populus yunnanensis were similar and contained primarily caffeic acid and its esters together with the flavanones pinocembrin and pinobanksin-3-acetate. The terpenoid patterns of the specimens examined varied, but this variation was not species related. On the basis of bud exudate analysis P. simonii and P. yunnanensis may be considered to represent a single species.
Characterization of Plastid 5-Aminolevulinate Dehydratase (ALAD; EC 4.2.1.24) from Spinach (Spinacia olevacea L.) by Sequencing and Comparison with Non-Plant ALAD Enzymes
Authors: Schaumburg Anke , Schneider-Poetsch Hansjörg A. W. , Eckerskorn C.
Published: August 2018

We have sequenced 5-aminolevulinate dehydratase (ALAD; EC 2.4.1.24) of a plant. A fulllength cDNA clone (1727 bp) encoding this enzyme has been identified by immunoscreening a lambda gt 11 cDNA library of spinach. ALAD is not a plant-specific enzyme; however, the plant enzyme differs from the well known ALAD enzymes of bacteria, yeast and animals in structural and biochemical properties and in that it is located in the plastid. Differences and homologies can be traced back to the molecular level. The mature ALAD subunit, whose N-terminus was determined by automatic Edman degradation, is a protein of 367 amino acid residues and has a Mr of 40,132. This figure is in the range of molecular weights of non-plant ALADs. The active centre is highly conserved and the same is true for the ion-binding domain, except that 4 cysteines of the non-plant enzymes (binding Zn2+) have disappeared and a total of 6 aspartic acids meets the demands of Mg2+-binding. However, there are more distinct differences. Apart from a transit sequence of 56 amino acids targeting the plastid, the N-terminal part of the mature plant enzyme differs considerably from non-plant ALAD enzymes. It is rich in prolines and hydroxylated amino acids. The apparent Mr on SDS-PAGE is 45,000 or higher, but up to now posttranslational modifications have not been found.
Comparison of the Substrate Specificities of Lipoxygenases Purified from Soybean Seed, Wheat Seed, and Cucumber Cotyledons
Authors: Matsui Kenji , Shinta Hiroyuki , Toyota Hiromitsu , Kajiwara Tadahiko , Hatanaka Akikazu
Published: August 2018

Lipoxygenases were highly purified from soybean seed, wheat seed and cucumber cotyledons. Substrate specificities of these lipoxygenases were studied by using an entire series of (ω6Z ,ω9Z )-C13~C24-dienoic acids as synthetic substrate analogues. Soybean lipoxygenase-1 and cucumber lipoxygenase showed broad specificities for these substrates while wheat lipoxygenase showed narrow specificities. Position of dioxygenation to each substrate was analyzed by high performance liquid chromatography. With soybean lipoxygenase-1 elongation of the distance between the terminal carboxyl group and the site of hydrogen removal in a substrate decreased the positional specificity of dioxygenation, while, with cucumber lipoxygenase, shortening the distance decreased the specificity. It was suggested that cucumber lipoxygenase and soybean lipoxygenase-1 recognized the terminal carboxyl group of a substrate to arrange it only in one orientation at the reaction center. In case of wheat lipoxygenase, recognition of the carboxyl group was thought to have crucial and essential role to secure the activity.
Pheromone 84 [1]. Der Sexualpheromonkomplex des „Braunen Bären“ Arctia caja (Lepidoptera: Arctiidae) / Pheromones, 84 [1]. The Sex Pheromone Complex of the Arctiid Moth Arctia caja (Lepidoptera: Arctiidae)
Authors: Bestmann H. J. , Kern F. , Mineif A. , Platz H. , Vostrowsky O.
Published: August 2018

By means of GC, GC/MS and GC-coupled electroantennogram techniques, (3Z,6Z,9Z)- 3,6,9-heneicosatriene (1), (3Z,6Z)-m-9,10-epoxyheneicosadiene (2) and (3Z,6Z)-cis-9,10- epoxyeicosadiene (3) were structurally elucidated as the biologically active components of the pheromone complex of Arctia caja (Lepidoptera: Arctiidae).
Isolation And Partial Characterization Of An L -Amino Acid Oxidase And Of Photosystem Ii Complexes From The Cyanobacterium Synechococcus PCC7942
Authors: Engels Dirk H. , Engels Anke , Pistorius Elfriede K.
Published: August 2018

An L-amino acid oxidase with high specifity for basic L-amino acids was isolated from the cyanobacterium Synechococcus PCC 7942, and the enzyme was partially characterized. This enzyme was compared to the previously described L-amino acid oxidase from Synechococcus PCC6301 (G. Wälzlein, A. E. Gau, and E. K. Pistorius, Z. Naturforsch. 43c, 5 4 5-553, 1988). In addition, photosystem II complexes were isolated from Synechococcus PCC 7942, and it could be shown that a 36 kDa polypeptide which crossreacts with the antiserum raised against the L-amino acid oxidase (50 kD a) is present in isolated PS II complexes from Synechococcus PCC 7942 as already shown to be the case for Synechococcus PC C 6301 (A. E. Gau, G. W älzlein, S. Gärtner, M. Kuhlmann, S. Specht, and E. K. Pistorius, Z. Naturforsch. 44c, 9 7 1 -9 7 5 , 1989). These results clearly show that in isolated photosystem II complexes from Synechococcus PCC 6301 as well as PCC 7942 a fourth polypeptide (besides D 1, D 2 and the manganese stabilizing protein) is present in the 30 kDa region and support our hypothesis suggesting that the water oxidizing enzyme is a separate protein (distinct from D 1 and D 2)
Disturbing Gtp-Binding Protein Function Through Microinjection Into The Visual Cell Of Limulus
Authors: Stieve Henmg , Niemeyer Barbara , Aktories Klaus , Hamm Heidi E.
Published: August 2018

We have tested the action of three agents microinjected into the ventral nerve photoreceptor of Limulus on the electrical response to dim light. 1. A monoclonal antibody (mAb 4 A) against the Gɑ subunit of frog transducin reduces the size of the receptor current to 60%, suggesting an interaction with Gɑ in the Limulus photoreceptor. 2. Injection of Clostridium botulinum ADPribosyltransferase C 3 reduces the size to 46%; latency is not affected. The results imply that small GTP-binding proteins play a functional role in photoreception of invertebrates. 3. Injection of GD P-β-S reduces dose-dependently the size of the receptor current to 15% and prolongs the latency to 200%, presumably by reducing number and rate of G-protein activations