bluuebunny/crossref_metadata_2025 huggingface dataset:
Monospecific Antibody against 5-Methyl-Cytidine for the Structural Analysis of Nucleic Acids
Authors: Mastronicolis Sofia K. , Kapoulas Vassilios M. , Kröger Hans
Published: August 2018

Anti 5-methyl-cytidine antibodies might be useful agents for the detection and localization of 5-methyl-cytidine of nucleic acids, but only if the antibodies recognize this nucleoside with sufficient specificity. A conjugate containing 18 moles of 5-methyl-cytidine per mole of BSA was prepared and antibodies directed against this nucleoside hapten were produced by immunization of rabbits (as determined by gel diffusion in agar containing excessive amounts of the carrier). A slight crossreaction of cytidine-BSA was eliminated by adsorption on the cross-reacting antigen. Further purification of the antibodies was effected by chromatography on DEAE-Sephadex A-50 and a method for the rapid quantitation of the antibodies showed that 12.7% of the IgG protein are monospecific against 5-methyl-cytidine-BSA. Hydrolysis of antibodies with insolubilized pa­pain produced monovalent Fab fragments which were identified by SDS-Disk-electrophoresis. A two stage method for cross linking the immunoproteins to ferritin by glutaraldehyde was used. The isolation of immunoferritin conjugates by Bio-Gel A 1.5 m column chromatography is described. The identification of the effluents was made by glycerin density gradient ultracentrifugation. The results were visualized by electron microscopy after the treatment of immunoferritin conjugates with (methylated and unmethylated) denaturated DNA, fractionation on the glycerine density gradient, and the spreading by a modification of drop technique.
Über die oxidative Hauptkettenspaltung einiger Nukleinsäuren — Pulsradiolytische Untersuchungen / On the Oxidative Main-Chain Scission of Nucleic Acids — Pulse Radiolysis Studies
Authors: Denk Otmar , Schnabel Wolfram
Published: August 2018

Polyriboadenylic acid, polyribocytidylic acid and polyribouridylic acid were irradiated with 16 MeV electrons in aqueous solution. Part of the OH radicals generated during the radiolysis of water reacted with the sugar moieties of the polynucleotides. Subsequently formed peroxyl radicals reacted with each other thus forming oxyl radicals whose's decay led to main-chain scissions with the consequence of a decrease of the light scattering intensity (LSI). In the case of single-stranded polynucleotides, the analysis of the LSI decay curves revealed the occurrence of two processes. The rapid mode was assigned to the intramolecular and the slow mode to the intermolecular reaction of peroxyl radicals. For the rate constant of the rapid process (activation energy: 5 kcal/mol) a pronounced kinetic salt effect was observed.

In the case of double-stranded polynucleotides (polyA and polyC at pH 4, poly(A+U) at pH 8) the same effects were observed as with native calf thymus DNA in a former study [9]: The LSI decreased only after a critical dose was surpassed. A rapid process was followed by a slow one. The slow process is assigned to the melting of H-bridges located at bases between main-chain scissons in the double helix. The rapid process corresponds to the separation of fragments formed by two single strand breaks laying very close to each other on opposite sites in the double helix.
ATPases of the Cat Carotid Body and of the Neighbouring Ganglia
Authors: Starlinger H.
Published: August 2018

The average ATPase activity in homogenates of the cat carotid body is found to be 20 nmol Pi liberated per minute per mg fresh tissue weight at 25 °C. ATPase activity in the nodose ganglion and the superior cervical ganglion is found in the same range. Most of the activity remains in the supernatant after removal of the mitochondria by centrifugation. The activity is inhibited by ouabain only marginally (ganglia) or not at all (carotid body). In all these organs up to 80% of the activity is seen in the absence of Mg2+ and the presence of increasing concentrations of Ca2+.
Notizen: Coenzyme Binding at Different Ionization States of Cytoplasmic and Mitochondrial Malate Dehydrogenase
Authors: Schwerdtfeger Klaus , Woenckhaus Christoph , Parker David M. , Holbrook John J.
Published: August 2018

pH-titrations with NADH show two ionizable groups in mitochondrial and cytoplasmic malate dehydrogenase, the first with a pKa in the range 6.8 -8.3 for the mitochondrial and 6.4-7.8 for the cytoplasmic enzyme, the second with a lower limit at 10.2 resp. 11. Comparison with bis-(dihydronicotinamide)-dinucleotide and dihydronicotina-mide-ribosyl-P2-ribose-pyrophosphate instead of NADH indicates that the second alkaline ionization is caused by a residue placed near the adenine binding site of the active centre of the two isoenzymes. Binding studies with NADH and NAD+ give evidence for the participation of a group in the mitochondrial enzyme with pKa 6.8, deprotonation of which is necessary for detectable association of NAD+. In contrast the fixation of NAD+ to the cytoplasmic enzyme is independent of pH.
6-C-α-L-Rhamnopyranosylapigenin 7-O-β-ᴅ-glucopyranoside (Isofurcatain 7-O-β-ᴅ-glucoside), a New Flavone Glycoside from Metzgeria furcata
Authors: Markham Kenneth R. , Theodor Renate , Mues Rudiger , Zinsmeister H. Dietmar
Published: August 2018

The isolation of 6-C-α-ʟ-rhamnopyranosylapigenin (isofurcatain) 7-O-β-ᴍ ᴅ-glucopyranoside, from Metzgeria furcata var. ulvula is described together with its identification. This is a new natural product, as also is isofurcatain.
Demethylation, Methylation and 3′-Hydroxylation of Isoflavones by Fusarium Fungi
Authors: Weltring K.-M. , Mackenbrock K. , Barz W.
Published: August 2018

Several introductionary reactions of isoflavone metabolism by Fusarium fungi are reported. Fusarium avenaceum hydroxylates formononetin in the 3′-position yielding 3′,7-dihydroxy-4′-methoxyisoflavone (calycosin). 3′-Hydroxylation of biochanin A to 3′,5,7-trihydroxy-4′-methoxyiso-flavone (pratensein) has been observed with Fusarium oxysporum f. sp. lycopersici and Fusarium oxysporum f. sp. lini. Depending on the growth medium Fusarium proliferatum metabolises for­mononetin either by 7-O-methylation or by 4′-O-demethylation.
Polynucleotide Phosphorylase from a Cyanobacterium (Synechococcus sp.): Subunit Composition and Properties
Authors: Nolden Wolf-Thomas , Richter Gerhard
Published: August 2018

Polynucleotide phosphorylase from cells of the cyanobacterium Synechococcus sp. has been purified 1400-fold by an improved procedure. The enzyme purified to homogeneity and lacking nuclease, phosphatase and protease contaminations reveals a single band of ADP polymerizing activity upon polyacrylamide gel electrophoresis under nondenaturing conditions which cor­responds to a molecular mass of about 275 000. The enzyme migrates as a single polypeptide of Mr ≈ 70 000 when subjected to gel electrophoresis in the presence of dodecyl sulfate indicating a composition of α4 for the native enzyme molecule. The isoelectric point of the purified enzyme as determined by isoelectric focusing was found to be at 4.2 ± 0.1. Polynucleotide phosphorylase of Synechococcus is preferentially activated by Mg2+; KCl has a significant stimulatory effect.
Equilibrium and Kinetic Studies of Calcium Transport and ATPase Activity in Sarcoplasmic Reticulum
Authors: Inesi G. , Kurzmack M. , Kosk-Kosicka D. , Lewis D. , Scofano H. , Guimaraes- Motta H.
Published: August 2018

A number of equilibrium and kinetic measurements are presented to characterize the partial reactions of the ATPase and transport cycle in sarcoplasmic reticulum vesicles. The cycle begins with calcium and nucleotide binding on sites available on the outer surface of the vesicles. A phosphorylated enzyme intermediate is then formed, and the calcium sites are subjected to a change in their orientation and their affinity for calcium. It is shown that steps involved in calcium release on the inner side of the vesicles are rate limiting for the cycle, and are followed by hydrolytic cleavage of the intermediate with release of inorganic phosphate and recycling of the enzyme.
Enzymatic Synthesis of Sinapine from 1-O-Sinapoyl-β-ᴅ-glucose and Choline by a Cell-Free System from Developing Seeds of Red Radish (Raphanus sativus L. var. sativus)
Authors: Strack Dieter , Knogge Wolfgang , Dahlbender Brigitte
Published: August 2018

A cell-free system from developing seeds of red radish (Raphanus sativus L. var. sativus) catalyzed the transfer of the sinapoyl moiety of 1-O-sinapoyl-β-ᴅ-glucose to choline to form O-sinapoylcholine (sinapine). A wide range of proportionality with respect to incubation time and protein concentration was found in the determination of this enzymatic activity using a high performance liquid chromatographic (HPLC) method. The transacylase activity showed an absolute acceptor specificity towards choline and a high hydroxycinnamoyl donor specificity with 1-sinapoylglucose. Maxim|al rate of sinapine formation was found to be around pH 7.0 in 0.08 M potassium phosphate buffer. The apparent Km values were 0.30 mм for 1-sinapoylglucose and 7.64 mм for choline.

Change in extractable transacylase activities from different stages of seed development correlated well with the in vivo accumulation kinetics of sinapine. Maximal activity around 36 pkat seed-1 and 129μkat kg-1 protein was extracted from dark-green immature seeds, which are in the process of rapid sinapine accumulation. About 20% of this activity still has been found in dark-brown mature seeds. This enzymatic acitivity refers to an enzyme which can be classified as 1-sinapoylglucose: choline sinapoyltransferase (SCT).
Inhibition of Ergosterol Biosynthesis by Etaconazole in Ustilago maydis
Authors: Ebert Edith , Gaudin John , Muecke Wolfgang , Ramsteiner Klaus , Vogel Christian , Führer Hermann
Published: August 2018

The triazole fungicide etaconazole (CGA64 251) interferes with the ergosterol biosynthesis in Ustilago maydis by inhibiting the C-14 demethylation of the sterol nucleus. During the late log growth phase of U. maydis a novel endogenous sterol metabolite (14α-methyl-ergosta-8,24(28)- dien-3β,6α-diol) was discovered and analyzed, which accumulates under the influence of the fungicide. The structure of this metabolite points to a hydroxylation-dehydration mechanism for the introduction of the double bond at C-5 during the ergosterol biosynthesis.
Studies on the S-State Distribution in Euglena gracilis
Authors: Schmid Georg H. , Thibault Pierre
Published: August 2018

When Euglena gracilis is dark adapted for 10 min or more, oxygen evolution as the consequence of short (5 μsec) saturating light flashes does not show the picture of a damped oscillation with a periodicity of 4, as known from the literature. The overall picture of this flash pattern is given by the fact that O2-evolution in the first two flashes is practically zero and rises from there onward in a continuous manner to the steady state with barely any visible oscillation at all. However, a second flash sequence fired one to two minutes after this first sequence induces an oxygen evolution pattern which is barely distinguishable from the well known usual Chlorella vulgaris pattern. The phenomenon is not influenced by changes in the oxygen tension nor do additions of chemicals like CCCP, sodium azide, or reducing agents like hydroxylamine or hydrogen peroxide substantially alter the described behavior. Deactivation experiments give the overall impression that the deactivation of the S-states is slower than with Chlorella. Hydroxylamine strongly accelerates the deactivation. The analysis of the S-state distribution in a four and five state Kok-model suggests that dark adapted Euglena is in a more reduced condition than dark adapted Chlorella. It looks as if dark adapted Euglena were in a condition which would correspond to 60 percent S-1, 30 percent S0 and 10 percent S1. The experimental flash sequence of such dark adapted cells fits best a synthetic sequence when the misses are in the region of 20-25 percent, with double hitting playing practically no role at all (the first two flashes are zero!). The impression that dark adapted Euglena starts its oxygen evolution from a more reduced state is strengthened by the analysis of room temperature fluorescence induction (Kautsky effect). It can be shown that the fluorescence induction curve of Euglena corresponds to that of Chlorella cells provided the latter have been briefly treated with a strong reductant such as sodium dithionite.
Effect of Organic Solvents on Enzymatic Hydrolysis of Celluloses
Authors: Kumakura Minoru , Kaetsu Isao
Published: August 2018

Effect of organic solvents on enzymatic hydrolysis of celluloses was studied. It was found that toluene and xylene can accelerate the rate of the enzymatic hydrolysis reaction of filter paper and cellulose powder. The addition of N,N-dimethylformamide, acetone, and alcohols was negative effect for the enzymatic hydrolysis of solid celluloses. In the addition of alcohols and glycols, the relative glucose yields increased with increasing the carbon number of their solvents. The addition of organic solvents on the enzymatic hydrolysis of celluloses was discussed with swelling effect. It was found that the glucose yield increased as the dipole moment of the solvents decreased.
Coupling of Monomethoxypolyethyleneglycols to Proteins via Active Esters
Authors: Boccù Enrico , Largajolli Roberta , Veronese Francesco M.
Published: August 2018

Two alternative methods for the attachment of monomethoxypolyethyleneglycols (PEG) to proteins are proposed; they are based upon the replacement of the hydroxy terminal function of PEG to carboxylate followed by its activation with dicyclohexylcarbodiimide and N-hydroxy-succinimide. The methods, which give more homogeneous product than that employing trichloro-s-triazine as coupling reagent, may also be used for the modification of essential -SH containing enzymes. The attachment of PEG activated via esters was tested with several model proteins and the influence of the extent of modification i. on the biological activity of various enzymes, ii. on the binding capacity for albumin and iii. on the clearance time in rats using superoxide dismutase as model tracer was evaluated. It was also demonstrated that the extent of PEG attachment varies greatly according to the different proteins used.
Fluorescence Patterns of Chromatin and Cytoplasm by Hematoxylin Solutions
Authors: Stockert J. C. , Molero M. L. , Espelosin R. H.
Published: August 2018

Hematoxylin, Fluorescence, Fluorochrom es Treatments o f chicken blood and Ehrlich ascites tumor smears with hematoxylin solutions give a fluorescence reaction in chromatin, basophilic cytoplasm and leukocyte granules. In these structures the fluorescence emission in­ creases upon dye aging and prolonged staining times. We present a preliminar spectral analysis suggesting the possibility to employ hematoxylin as a fluorochrome.
Selection of Cell Lines of Catharanthus roseus with Increased Tryptophan Decarboxylase Activity
Authors: Sasse Florenz , Buchholz Marita , Berlin Jochen
Published: August 2018

Cell lines of Catharcmthus roseus were selected for resistance to 4-methyltryptophan (4-MT) in order to get strains with increased activities of tryptophan decarboxylase (TDC). This enzyme may exert a decisive regulatory control in indole alkaloid biosynthesis. 4-Methyltryptophan is a substrate for TDC and is detoxified by this enzyme. All 4-MT resistant cell lines showed increased TDC activity (3-to 10-fold) and higher accumulation of tryptamine (3- to 5-fold). Two of these cell lines with increased TDC activity accumulated indole alkaloids in the growth medium, whereas in wild type cultures and other resistant cell lines this was not the case. All the cell lines obtained were not only resistant to 4-MT (20- to 70-times more than wild type cells) but were also cross-resistant to other tryptophan analogues which are not metabolized by TDC. Therefore the resistance was not only due to a better detoxification of the analogue. The selected cell lines also contained 2 to 6 times higher levels of ʟ-tryptophan but the feedback sensitivity of the anthranilate synthetase of the resistant cells was not alteref
Chlorophyll-Lipid-Interactions in Monomolecular Layers
Authors: Heithier H. , Möhwald H.
Published: August 2018

Mixed monolayers containing chlorophyll a and dim yristoyllecithin (DML) have been investigated by simultaneous thermodynamic, fluorescence and absorption spectroscopic measurements. It has been shown that the solubility limit of chlorophyll a in the fluid, as well as in the solid lipid matrix, is above 20 mol%. This contrasts to previous findings for pheophytin a containing monolayers and indicates the existance of an interaction between the phospholipid head group and the central Mg atom.

A fluorescence decrease on solidifying the monolayer was observed and it is suggested that it is due to an enhanced self quenching as a consequence of the reorientation of the porphyrin rings, accompanying the phase transition
Zusammensetzung und Akkumulation des ätherischen Öls in Matricariae Radix (2. Mitteilung) / Composition and Accum ulation of Essential Oil in Matricariae Radix (2. Com munication)
Authors: Reichling Jürgen , Bisson Walter , Becker Hans , Schilling Gerhard
Published: August 2018

The essential oil of Matricaria chamomilla roots has been investigated. Besides the known compounds for this plant organ trans-β-farnesene,trans-α-famesene, chamomillaester I and II, we found the two spiroether only described for the aeriel parts. β-caryophyllene, cis-caryo hyllene and caryophyllenepoxid are found for the first time in Matricaria chamomilla. One of the main constituents is a hitherto unknown sesquiterpene-alkohol with muurolene-structure. With the aid of spectroscopical data (1H-NMR, 13C-NMR, MS) we determined its structure. We propose the name chamomillol for the new compound.

Besides the known resin ducts longitudinally orientated we found resin ducts transversally orientated and oil cells
Flavon C-Glykoside aus Metzgeria furcata (Hepaticae) / Flavone C-Glycosides from Metzgeria furcata (H epaticae)
Authors: Theodor R. , Mues R. , Zinsmeister H. D. , Markham K. R.
Published: August 2018

From Metzgeria furcata (L.) Dum. and M. furcata var. ulvula Nees. 12 different flavone Cglycosides were isolated and identified; 4 of them are common to both varieties. The detected compounds are three tricetin 6,8-di-C-glycosides, one of them 6-C-β-D-glucopyranosyl-8-C-a-Larabinopyranosyltricetin being a new compound, three luteolin C-glycosides and 6 apigenin Cglycosides. The occurrence o f these flavone C-glycosides in M. furcata is discussed in relation to earlier work on flavonoids in Metzgericeae
Optically Detected Magnetic Resonance of Porphyrin Complexes in the Bacterium Rhodopseudomonas sphaeroides
Authors: Beck J. , Schütz J. U. von , Wolf H. C.
Published: August 2018

By ODMR in zero-field the porphyrins of the BChl-biosynthesis in whole cells of Rhodopseudomonas sphaeroides R-26 are investigated. In the optical emission spectrum 11 pigments could be identified using ODM R in combination with emission and excitation spectroscopy. The properties of these pigments were analyzed in respect to their interactions with the surrounding molecules. An energy transfer from the triplet state of Zn-protoporphyrin to the antenna pigm ent singlet system was proved by DE-ODMR. The wavelength dependence of the zfs param eters within the individual emission band is explained by a model of selective spin-orbit-coupling. In the case of the precursors chlorophyllide a and pheophorbide a, for example, we could show that the pigments are bound to proteins via a hydrogen bond to the ketocarbonylgroup of ring V and that porphyrins with a central Mg-atom have an additional bond via a Fifth ligand of the Mg
Is the Fly Visual Pigment a Rhodopsin?
Authors: Vogt Klaus
Published: August 2018

Thin layer chromatography of retina extracts from Calliphora yielded, instead of retinal (or retinaloximes after NH2OH treatm ent) a considerably more polar aldehyde or its corresponding oximes. That these compounds originate from the chrom ophoric group of the visual pigment was shown by the occurrence of different stereoisomers in the extracts depending on the colour with which the intact visual pigment complex was previously illuminated. The absorbance maximum of the oxime found after blue illumination is the same as that of all-trans-retinal-oxime (356 nm). This spectral accordance means that previous spectral evidence for retinal as the chromophoric group of fly visual pigment is not conclusive. Flies raised on a carotenoid deficient diet enriched with the hydroxy-xanthophyll lutein possess a high visual pigment content. This points to a hydroxy- xanthophyll as a possible precursor of the chromophoric group
Circulardichroism of C-Phycocyanin: Origin of Optical Activity in Denatured Biliproteins and Evidence for an Intermediate during Unfolding
Authors: Lehner Harald , Scheer Hugo
Published: August 2018

The circulardichroism spectra (cd) of native and (partially) urea-denaturated C-phycocyanin (PC) in the spectral range 700-210 nm are presented. The large ellipticities observed in the chromophoric region of native PC are retained in the fully denatured state (8 ᴍ urea). This is similar to the behavior of the red form of phytochrome (Pr), but in contrast to C-phycoerythrin (PE). These differences are rationalized in terms of epimeric equilibria between P- and M-helix shaped chromophores. Depending on the number and location of the chirality centers present in the tetrapyrrol moities a priori, the excess populations of the inherently chiral P- and M-helices differ, thus accounting for large (PC, Pr) or small (PE) ellipticities in the denatured pigments. Hence, the large optical activity observed for the former is generated by an excess population of the P-helix induced by the asymmetric C-2, C-3 and C-3'. In PE the additional chirality center at C-16 counteracts the influence of the others. The excess population of the inherently chiral species is therefore lowered, in agreement with the nearly vanishing cd reported for denatured PE.

The cd has also been studied at intermediate urea concentrations. Unfolding of PC with urea can be interpreted from these data as a stepwise process. Monitoring the urea induced unfolding of PC by cd at different wavelengths (λ = 220, 345, and 610 nm); the “melting point” of the apoprotein (4 -5 ᴍ urea) coincides with the extrema of the titration curves obtained in the chromophore region (345, 610 nm). These results give direct evidence for the existence of an intermediate species whose population reaches a maximum at 4-5 ᴍ urea.
Comparison of Purine Metabolism in Suspension Cultured Cells of Different Growth Phases and Stem Tissue of Catharanthus roseus
Authors: Hirose Fumiko , Ashihara Hiroshi
Published: August 2018

The overall metabolism of [8-14C]adenine, [8-14C]adenosine, [8-14C]guanine, [8-14C]hypoxan- thine and [8-14C]inosine in suspension cultured cells of the lag, cell division, cell expansion and stationary phases and stem tissue of Catharanthus roseus was studied. On a fresh weight basis, absorption of all purine bases and nucleotides by the cultured cells was 10-400 times higher than that by the stem tissue. The conventional pathways of purine salvage and degradation were operative both in the cultured cells and stem tissue. [8-14C]Adenine and [8-14C]adenosine were extensively salvaged to nucleotides and nucleic acids in both the cultured cells and the stem tissue. [8-14C]-Guanine, [8-14C]hypoxanthine and [8-14C]inosine were incorporated into either salvage products (nucleotides and nucleic acids) or degradation products (CO2, allantoin and allantoic acid) of cultured cells and stem tissue. The highest incorporation rate expressed as a percentage of absorbed 14C into the degradation products was observed in the lag phase (12h-old) cultured cells. Incorporation of all precursors into nucleotides and bases was much higher in the stem tissue than in the culltured cells.
Uptake and Conversion of Three Different 5-Ring Polycyclic Aromatic Hydrocarbons (PAHs) in Cell Suspension Cultures of Various Chenopodiaceae-Species
Authors: Harms Hans
Published: August 2018

Three l4C-labelled 5-ring PAHs, benzo(a)pyrene, dibenz(a,h)anthracene and perylene were added to various cell suspension cultures of plants belonging to the Chenopodiaceae family. The differently configurated 5-ring systems varied in uptake and metabolism. The uptake of benzo(a)pyrene was highest in all cell cultures tested whereas the assimilation of dibenz(a,h)an­thracene and perylene was significantly less. The uptake of benzo(a)pyrene and dibenz(a,h)- anthracene was highest in those cultures which showed the highest increase in biomass. In contrast the uptake of perylene was highest in cultures whose increase in biomass was less.

Previous investigations (H. Harms, W. Dehnen and W. Monch, Z. Naturforsch. 32 c, 321 -326 (1977)) showed that benzo(a)pyrene is metabolized to quinones and other oxygenated derivatives by Chenopodium rubrum cell cultures. It was demonstrated now that in further reactions these compounds are incorporated into insoluble fractions. With increasing time of incubation the amount of radioactivity in the extracted residue increased. The proportion of oxygenated derivatives formed seems to be correlated with the incorporation of radioactivity into insoluble fractions. Dibenz(a,h)anthracene turned out to be the most stable 5-ring system whereas perylene is metabolized to a certain extent but only small amounts of radioactivity could be detected in the extracted insoluble residue.

The experiments showed that plant cell cultures maintain their specific behaviour over long periods. On the other hand each of the chemical compounds, because of its molecular size and configuration, is subject to its own specific metabolism in plant systems.
Interconversion of Carotenoids and Quinones after Onset of Photosynthesis in Chloroplasts of Higher Plants
Authors: Grumbach K. H.
Published: August 2018

The interconversion of carotenoids and quinones was investigated in beech and spinach leaves as well as isolated intact spinach chloroplasts following a dark-light transition. It is shown that isolated intact chloroplasts which are preincubated for 2 h at pH 7.6 in the dark and re­illuminated with strong white light are capable not only of deepoxidizing violaxanthin into antheraxanthin and zeaxanthin but simultaneously change the redox state of the plastoquinone- pool in their thylakoid membrane. At the same time as violaxanthin is deepoxidized plastohydroquinone-9 is oxidized to plastoquinone-9. If the light is turned off zeaxanthin is epoxidized into antheraxanthin and violaxanthin but no significant change in the redox state of the plastoquinone-pool occurred.

It is concluded that the deepoxidation of violaxanthin is connected to the photosynthetic electron transport in that way that an acidification of the intrathylakoidal compartment by the vectorial release of protons from the water photooxidizing enzyme system and the plastoquinone- pool is required for the activation of the violaxanthin deepoxidase. This may be taken as further evidence that violaxanthin deepoxidase is located at the inner side of the thylakoid membrane. Additional evidence for this location site is given by the observation that neither deepoxidation of violaxanthin nor photooxidation of plastohydroquinone-9 occurred after onset of photosyn­thesis if non cyclic electron transport was inhibited by DCMU.
A Membrane Bound Cysteine Oxydase from the Cyanobacterium Synechococcus 6301
Authors: Schmidt Ahlert , Krämer Elisabeth
Published: August 2018

Membrane fractions of the cyanobacterium Synechococcus 6301 obtained by french press treatment following sonication catalyzed an oxygen-dependent oxydation of cysteine to cystine. For 1 O2 consumed four cysteine were oxydized. Oxygen uptake was completely inhibited by 1 mᴍ KCN. Only ᴅ- and ʟ-cysteine were active and partial activity was observed with ᴅʟ-homocysteine and cysteamine. No activity was found with glutathione, mercaptoethanol, thioglycerol, dithioerythritol, or N-acetyl-ʟ-cysteine. Cysteines with a blocked acid group such as O-methyl-ʟ-cysteine and O-ethyl -ʟ-cysteine were oxydized rapidly by Synechococcus membrane fractions. Rates of about 200 μmol of cysteine oxydized per mg chlorophyll and hour were measured. This cysteine respiration is discussed in relation to dark inactivation of enzymes.
Inheritance of Sesquiterpenoid Phenolic Acid Esters (Guayulins) in F1 Hybrids of Parthenium (Asteraceae)
Authors: Behl H. Mohan , Marchand Bernard , Rodriguez Eloy
Published: August 2018

High performance liquid chromatography was used to quantify the sesquiterpene phenolic esters, Guayulin A and -B in Parthenium argentatum (guayule) and F1 hybrids of guayule with Parthenium schottii, P. fruticosum var. trilobatum and P. tomentosum var. stramonium. The distri­bution of these phenolic acid esters in all parts of the plants are reported and their inheritance in hybrids is discussed.
Umwandlungen von Phenazinen in Pseudomonas aureofaciens [1] / Transformations of Phenazines in Pseudomonas aureofaciens
Authors: Römer A. , Lange E.
Published: August 2018

Transformation of phenazines in Pseudomonas aureofaciens were investigated with deuterated phenazine-1-carboxylic acid, 2-hydroxyphenazine-1-carboxylic acid, phenazine-1,6-dicarboxylic acid, methyl phenazine-1-carboxylate, dimethyl phenazine-1,6-dicarboxylate, and its mono methyl derivative. It was shown that hydroxylation and decarboxylation of phenazine-1-carboxylic acid gave rise to the variety of phenazines isolated from this strain.
Distribution and Variation of the Catalytic Activity of the Enzyme Responsible for Carthamin Synthesis in Safflower Seedlings
Authors: Saito Koshi , Takahashi Yoshiyuki , Wada Mizu
Published: August 2018

Catalytic activityof the enzyme which mediates the synthesis of carthamin was examined in the etiolated hypocotyl tissues of Carthamus tinctorius L. The enzyme was optimally active at pH 5.2 in citrate buffer. The activity of the enzyme was highest in the extract from 2-day-old seedlings after sowing and it declined sharply with tissue ageing. The enzyme activity was localized in the apical region of the seedlings and moreover it was preferentially associated with the cytosol fraction.
Further Studies on Induction of Enzymes of Phytoalexin Synthesis in Soybean and Cultured Soybean Cells
Authors: Leube Joachim , Grisebach Hans
Published: August 2018

The glucan elicitor from cell walls o f the fungal pathogen, Phytophthora megasperma f. sp. glycinea, caused a decrease in activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase in wounded soybean cotyledons, whereas wounding alone led to an increase in the activity of this enzyme. A decrease o f HMG -CoA reductase activity after elicitor treatment was also found in soybean hypocotyls and soybean cell cultures.

In contrast to the activity o f HMG -CoA reductase, the activity of dimethylallylpyrophosphate: 3,6a,9-trihydroxypterocarpan dimethylallyltransferase increases after elicitor challenge of soy­bean cell cultures and after inoculation of soybean hypocotyls (cv Amsoy 71) with mycelium of either race 1 (incompatible) or race 3 (compatible) of P. megasperma.
The Use of O2-Evolving Subchloroplast Particles to Study Acceptor and Inhibitor Sites on the Reducing Side of Photosystem II
Authors: Cohen W. S. , Barton J. R.
Published: August 2018

Photosystem II particles that retain the ability to evolve O2 have been used to examine acceptor and inhibitor sites in the photosynthetic electron transfer chain between Q and plastoquinone. Employing the water to dichlorobenzoquinone reaction to assay photosystem II activity, we have demonstrated that electron transport in thylakoids and particles is equally sensitive to inhibition by DCMU. dinoseb, metribuzin, HQNO and DBMIB. Based on differential sensitivity to inhibition by DCMU vs. HQNO or DBMIB, we suggest that when synthetic quinones, e.g. 2,6-dichlorobenzoquinone operate as Hill reagents in particles they are reduced primarily by the plastoquinone pool. When synthetic quinones, e.g. 5,6-methylenedioxy-2,3-dimethyl benzoquinone act as autoxidizable acceptors they accept electron from the Q/B complex at a point that is located between the DCMU and HQNO (DBMIB) inhibition sites.
Analoga des Hippurans: [103Ru]Ruthenocenoyl-glycin-Derivate. Synthese, Organ-Verteilung und Clearance /Analogue of Hippuran: Labelled Ruthenocenoyl-glycin. Synthesis, Organ Distribution and Clearance
Authors: Wenzel Martin , Schachschneider Gert
Published: August 2018

The analogue of hippuric acid, ruthenocenoyl-glycine was synthesized and labelled with the γ-emitter 103Ru. As a by-product of the synthesis the labelled diamide from ruthenocene- dicarbonic acid and glycine was gained. With these ruthenocene derivatives the organ distribu­tions in mice and rats were measured.

All ruthenocene-glycine derivatives showed primary a high kidney accumulation followed by very rapid renal excretion. After application of the cytostatic PtCl2(NH3)2, causing toxic effects in the kidney of mice, the excretion of ruthenocenoyl-glycine is decreased. Biochemical data suggest the use of labelled ruthenocenoyl-glycine as a substitute for Iodo-labelled hippuran.
Preparation and Characterization of Actin from Liver
Authors: Jaberg B.
Published: August 2018

G-actin was prepared from pork liver by gelfiltration on AcA 44 Ultrogel. The purity of the actin was 95-98% and the yield was 45-150 mg from 500 g liver, corresponding to a maximum efficiency of recovery of about 30%.

High viscosities of actin-enriched solutions were reduced by a specific pH-step. In SDS-gel electrophoresis a single band of about ~ 45000 daltons was seen. The G-actin was polymerizable as shown by high shear viscosity measurements. The isoelectric points of the β- and γ-isoactins were 5.6 and 5.7.
Use of Chlorophyll Fluorescence Induction Kinetics to Study Translocation and Detoxication of DCMU-Type Herbicides in Plant Leaves
Authors: Ducruet J. M. , Gaillardon P. , Vienot J.
Published: August 2018

Transient levels of the fluorescence induction rise were used to quantify partial photosynthesis inhibition by DCMU -type herbicides in whole leaves. Assays in different crop or weed species showed a good accuracy in measurements (generally, variation was lower than 5%). This technique was applied to the problem of varietal selectivity of wheat towards chlortoluron.
Redox-State Dependent Changes of Inhibitor-Binding to the Photosystem II Acceptor Complex
Authors: Urbach Wolfgang , Laasch Henrik , Schreiber Ulrich
Published: August 2018

Binding of radioactively labelled DCMU, ioxynil and terbutryn to spinach chloroplasts is determined following preillumination by single-turnover, saturating light flashes. With all of the three herbicides binary oscillations of binding are observed. Dark-adapted samples, or those preilluminated by an even number of flashes, bind more inhibitor than samples preilluminated by an odd number of flashes. Binding oscillations depend on inhibitor incubation time and on the seasonal adaptation of the plants. The binding kinetics following a single flash display three phases, the last two of which can be correlated with reoxidation kinetics of the secondary photo- system II acceptor Q-
в, as determined by fluorescence measurements. Analysis of the binding at DCMU concentrations up to 10-7 m free DCMU yields identical binding constants for dark- and flash preilluminated samples, but much less binding sites following one flash. It is concluded that up to 10-7 m free DCMU, centers with bound do not contribute significantly to total binding. Displacement of Q-
в from the binding site is half-saturated at about 10-6 M DCMU, as monitored via fluorescence induction. The data are considered strong support for the Velthuys ‘inhibitor- Q-
в competition model’.
Multiple Modes of Action of Diphenyl Ethers
Authors: Böger Peter
Published: August 2018

Diphenyl ethers are the most versatile phytotoxic compounds known so far with respect to their targets in the plant cell. According to their substituents, the following modes of action can be found: (a) inhibition of photosynthetic electron transport effective at two binding sites, (b) peroxidative activity (degradation of cellular constituents), (c) inhibition of carotenogenesis, (d) decrease of ATP-synthase (CF1) activity, (e) inhibition of respiratory electron transport, (f) stress response. This paper presents a condensed overview.
Photodynamic Damage to Isolated Chloroplasts: A Possible Model for in vivo Effects of Photosynthetic Inhibitor Herbicides
Authors: Percival Michael P. , Dodge Alan D.
Published: August 2018

The breakdown of chlorophylls, carotenoids, and linolenic acid together with the formation of malondialdehyde and ethane was followed in isolated pea chloroplast membranes. Breakdown was enhanced by light, oxygen, D2O and rose bengal, but retarded by crocetin. The results are discussed in relationship to the role of singlet oxygen in promoting damage in vivo.
The Effect of Phosphinothricin on the Assimilation of Ammonia in Plants
Authors: Wild Aloysius , Manderscheid Remigius
Published: August 2018

The effects of ᴅʟ-phosphinothricin and L-methionine sulfoximine on the enzymes of nitrogen assimilation were studied. Furthermore we investigated the accumulation of ammonia and the photosynthetic activity after the treatment of mustard plants with phosphinothricin. Phosphino-thricin was a specific and very strong inhibitor of glutamine synthetase. Major differences, however, were found between the phosphinothricin affinity of the leaf enzyme and that of the root of mustard plants. The leaf enzyme was 50% inhibited at a concentration of 10-4 m phosphinothricin (pI50 = 4), whereas the root enzyme already showed the same effect at a concentration of 2 × 10-5m (pI50 = 4.7). In addition Ki values of about 0.03 mм for the leaf enzyme and 0.002 mм for the root enzyme respectively were determined. Phosphinothricin treatment of plants caused an ammonia accumulation in tissues. The accumulation was light dependent. At the beginning of the light period the major sources of ammonia accumulation could be the nitrogen assimilation as well as catabolic processes of nitrogen compounds. A clear contribution of photorespiration was only found when higher concentrations of ammonia were reached. The application of phosphinothricin induced a strong reduction of CO2 assimilation.
Pheromone-Binding and Matrix-Mediated Events in Sexual Induction of Volvox carteri
Authors: Gilles Rainer , Gilles Claudia , Jaenicke Lothar
Published: August 2018

Sexual differentiation of the reproductive cells (gonidia) of the green alga Volvox carteri f. nagariensis Iyengar is triggered by a glycoprotein inducer which is released into the medium by sexual male spheroids. If added, it induces the next generation cycle to become sexual. About 3000 pheromone molecules per spheroid will give full induction. Specific binding sites for the pheromone have been identified in the extracellular matrix in which characteristic events take place. Inducer binding and action are reversible for a certain time period until the start of cell division; thereafter, determination of the gonidia is final. Extent of sexual induction is proportional to the duration of inducer pulses. Inhibition of sexual induction reveals as essential extracellular components of the induction system high molecular acidic glycoproteins, cyclic nucleotides, Ca2+/calmodulin, and pheromone-controlled gene products. Low matrix levels of cyclic AMP and cyclic GMP seem to stimulate induction; high levels to inhibit.
Cyanoacrylate Inhibitors of the Hill Reaction III. Stereochemical and Electronic Aspects of Inhibitor Binding
Authors: Huppatz John L. , Phillips John N.
Published: August 2018

Ethoxyethyl 3-octylamino-2-cyanoacrylate and related compounds in which the amino group was replaced by N-CH3, S, O and CH2 were synthesized and their activity as inhibitors of the Hill reaction in isolated pea chloroplasts determined. All compounds showed moderate to high activity but there was no obvious correlation between activity and the electronic character of the ester carbonyl group. The stereochemistry of the various inhibitor molecules was deduced from the PMR spectra and the possible influence of stereochemistry on Hill inhibitory activity discussed. Replacement of the olefinic proton in the 2-cyanoacrylates with a β-alkyl substituent was examined and a specific relationship between the length of the alkyl chain and activity was observed.
Effect of Electron Transfer Inhibitors and Uncoupling Agents on the Chlorophyll Fluorescence Lifetime during Slow Fluorescence Decline in Bean Leaves and Intact Chloroplasts
Authors: Kotova Elena A. , Il’ina Marina D.
Published: August 2018

Fluorescence measurements were performed with bean leaves and intact chloroplasts, which are characterized by a slow fluorescence decline. The fluorescence lifetime (ι) and the fluorescence relative quantum yield (φ) of intact chloroplasts, measured with the phase fluorometer, showed nearly proportional light-induced decrease with a halftime of ∼ 30 s, which was removed by 3-(3.4-dichlorophenyl)-1.1 -dimethylurea (DCMU), by 4.5,6,7-tetrachloro-2′-trifluoromethylbenzimidazole (TTFB). by carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) at a low concentration and by gramicidin D. Simultaneously the slow light-induced increase in absorbance at 518 nm (ΔA518), reflecting thylakoid membrane energization, was eliminated. The data on ι of intact chloroplasts are original, the other results agree with literature data. In leaves, the slow light-induced fluorescence decline, with ι dropping from ∼ 2 to ∼ 0.6 ns, was abolished by FCCP at a concentration of 5 μm. However, while ι was stabilized at a level close to the initial (maximum) one or somewhat higher, φ became close to the minimum value. Besides, the amplitude of ΔA518 was lowered about three times. These effects seemed to be due to multiple action of FCCP as a protonophoric uncoupler and an electron transfer inhibitor. In the presence of another uncoupling agent, TTFB, which, besides, is a diuron-like inhibitor of the electron transfer in chloroplasts, we observed the light-dependent, but hardly linked to changes in membrane potential, great increase in ι of a leaf from ∼ 1.9 to ∼ 4 .3 ns, with φ decreasing slightly. Addition of DCMU together with FCCP to the incubation medium or infiltration of a leaf with DCMU alone stimulated the rise in ι only to ∼ 3 ns. The increase in ι of a leaf observed in the presence of FCCP and DCMU, and especially with TTFB, may be associated with protein conformation changes which (i) alter the lifetime of nanosecond recombination luminescence of the photosystem II and/or (ii) disturb excitation energy transfer from the light-harvesting chlorophyll a/b complex to other pigment-protein complexes.
The Influence of Cysteine on the Reaction of d-Guanosine with cis -Diamminedichloroplatinum (II)
Authors: Kulamowicz Irena , Olinski Ryszard , Walter Zofia
Published: August 2018

Mono-and bifunctional complexes of cis DDP and d-guanosine were isolated on Sephadex G-25. The presence of cysteine in incubation mixture resulted in the vanishing of bifunctional com plex of d-guanosine and the appearance of d-guanosine-cis DDP-cysteine complex in the eluted peak. It is also possible that the eluted peak contained no homogeneous product of the reaction.
Insulin Binding Sites Induced in the Tetrahymena by Rat Liver Receptor Antibody
Authors: Csaba G. , Kovács P. , Inczefi-Gonda Ágnes
Published: August 2018

Tetrahvmena cells treated with purified rabbit anti­ bodies to rat hepatocellular membrane exhibited a consider­ able increase in binding capacity on reexposure to the antibody 24 h later. Insulin binding was similarly enhanced by preexposure to the antibody, and vice versa, preex­ posure to insulin enhanced the later binding of rat liver receptor antibodies. This suggests that (1) the Tetrahymena and the rat possess similar insulin receptors, and (2) the receptor antibody is also able to induce imprinting for itself as well as for insulin. Concanavalin-A, noted for binding overlap with insulin, failed to induce imprinting either for insulin or for antibodies to receptors, whereas the latter did induce imprinting for Concanavalin-A.
Incorporation of Radiolabeled Tyrosine, N-Acetyldopamine, N-β-Alanyldopamine, and the Arylphorin Manducin into the Sclerotized Cuticle of Tobacco Hornworm (Manduca sexta) Pupae
Authors: Grün Lothar , Peter Martin G.
Published: August 2018

Radiolabeled manducin, which is the arylphorin (i.e. tyrosine-rich larval serum protein) of the tobacco hornworm Manduca sexta was prepared by in vivo biosynthesis from [U-14C]-ʟ-tyrosine. In order to see whether manducin is incorporated into the cuticle of developing pupae and participates in cuticle sclerotization, the radiolabeled protein was injected into late last larval instar larvae. Fractionation of the sclerotized pupal cuticle into a buffer soluble, acid soluble and acid insoluble fraction shows that up to 2.6% of peptidic tyrosine residues end up in the acid soluble portion. Another 0.5% are recovered from the acid insoluble fraction by combustion. Only 30% of peptidic tyrosine residues of manducin incorporated into the acid soluble fraction are recovered as tyrosine. The presence of radioactivity in the acid insoluble fraction suggests that peptidic tyrosine residues are transformed partly into melanin-like material. The in­corporation of manducin into the cuticle of pupae is also evident from immunological studies.

Relative large quantities of radiolabeled acid insoluble melanine like material is also recovered from sclerotized cuticle after incorporation of radiolabeled tyrosine as well as tanning substrates N-acetyldopamine and N-β-alanyldopamine. Application of doubly labeled [7-3H,8-14C]-N-acetyldopamine shows a high loss of 3H in the acid insoluble fraction. It is suggested that tanning agents form lignine-like polymers and that sclerotization results from copolymerization with peptidic tyrosine residues in the cuticle. Thus, the arylphorin manducin appears to be an important constituent of the sclerotization system in Manduca sexta.
Juvenile Hormone III as a Natural Ligand for Photoaffinity Labelling of JH-Binding Proteins
Authors: Stupp Hans-Peter , Peter Martin G.
Published: August 2018

Juvenile hormone III, i.e. methyl 10,11-epoxy-3,7-dimethyl-2E,6E-dodecadienoate, was used for photoaffinity labelling of JH-binding proteins. Irradiation of haemolymph from Manduca sexta and Locusta migratoria in the presence of racemic [10-3H]JH-III results in covalent incorporation of up to 3.2% of the radioactivity into an acetone insoluble protein fraction. Resolution of the proteins by HPLC and by SDS-PAGE confirms the presence of radiolabelled JH-binding proteins. Proteins not involved in JH-binding in insect haemolymph are labelled photochemically with lower yields only. Thus, JH-III is a suitable natural ligand for photoaffinity labelling of high-affinity binding sites. Use of the natural hormone instead of a hormone analog bears the major advantage that the binding with a JH-binding protein will occur at specific sites.
Stimulation of Brain Synaptosome - Associated Adenylate Cyclase by Acidic Phospholipids
Authors: Tsakiris Stylianos
Published: August 2018

Phosphatidylserine (PS), phosphatidylinositol (PIN) or phosphatidylglycerol (PGL) incubated with synaptosomal plasma membranes (SPM) of dog brain, stimulated adenylate cyclase. The enzyme activity showed a dramatic increase at around 1.6 μmol PS/mg protein, while use of higher concentrations led to inhibition of the activity with respect to the maximal percentage of stimulation. Moreover, PS stimulated the dopamine-sensitive adenylate cyclase. Solubilization of SPM by the detergent Lubrol-PX did not affect the enzyme activation induced by dopamine. The solubilization, also, showed that the enzyme activity does not change at any PS, PIN or PGL concentration used. These results indicate that acidic phospholipids do not directly act on adenylate cyclase, but indirectly, affecting the membrane fluidity probably. Such modifications of interactions through lipid-protein(s) of adenylate cyclase may have implications to physiological responses to hormones or/and neurotransm itters in the central nervous system.