bluuebunny/crossref_metadata_2025 huggingface dataset:
“Prebumps”: Evidence for Double-H its at Functional Subunits in a Rhabdomeric Photoreceptor
Authors: Hamdorf K. , Kirschfeld K.
Published: August 2018

In fly photoreceptors the latency of “bumps” due to single photon absorption is in the mean 60-70 (± 20) ms (10 °C). With increasing stimulus intensities first the amplitude of the receptor potential increases without shortening of the latency; with still higher intensities the latency is reduced also. The first reduction occurs if neighboured microvilli are simultaneously hit by one light quantum each or if individual microvilli are hit by two quanta. Such “double hits” lead to a discrete reduction in latency which is manifested as a “prebump”.
Phytoalexins from Dolichos biflorus
Authors: Keen Noel T. , Ingham John L.
Published: August 2018

Genistein, 2′-hydroxygenistein, dalbergioidin, kievitone and phaseollidin have been found to accumulate in leaves and stems of Dolichos biflorus (horsegram) following inoculation with the non-pathogens Pseudomonas pisi and Phytophthora megasperma f. sp. glycinea, respectively. They are accompanied by isoferreirin (5,7,4′-trihydroxy-2′-methoxyisoflavanone), a compound not previously reported as a natural product. Coumestrol and psoralidin occur constitutively in Dolichos leaves and stems.
Folding and Association of Triose Phosphate Isomerase from Rabbit Muscle
Authors: Zabori Stefan , Rudolph Rainer , Jaenicke Rainer
Published: August 2018

The enzymatic activity and quaternary structure of rabbit muscle triose phosphate isomerase remains unchanged in the concentration range from 2 μg/ml to 2 ng/ml. In this concentration range the enzyme can be reactivated after dissociation and denaturation in 6.5 ᴍ guanidine hydrochloride. Removal of the denaturant by dilution and separation of inactive wrong aggregates (5-20%) lead back to active dimers, indistinguishable from the native enzyme as far as enzymatic and physicochemical properties are concerned. Based on the long term stability of the enzyme, the reactivation kinetics were analyzed at low concentrations and 0 °C, conditions where the association of inactive monomers to active dimers is predominant in the process of reactivation. The concentration dependence of the rate of reactivation and the kinetic profiles could be described by a consecutive first-order folding and second-order association reaction scheme with the rate constants kuni = 1.9 × 10-2 s-1 and kbi = 3 × 105 ᴍ-1 · s-1. This implies that the folded monomers of triose phosphate isomerase, which are intermediate states during reconstitution, cannot possess appreciable enzymatic activity.
Membrane Fusion and Deformation of Red Blood Cells by Electric Fields
Authors: Scheurich Peter , Zimmermann Ulrich , Mischel Maja , Lamprecht Ingolf
Published: August 2018

Human red blood cells suspended in a slightly hypotonic solution of low electric conductivity were exposed to an inhomogeneous and alternating electric field (sine wave, 30 V peak-to-peak value, electrode distance 120 μm, 0.5 to 2 MHz). Due to the dielectrophoretic effect the cells align parallel to the field lines under the formation of pearl chains. At high voltages (10 V amplitude) membrane fusion is observed between the adhered red blood cells in the pearl chains, whereby the chains become attached to the electrodes. In contrast to the pearl chains observed at voltages of up to 5 V amplitude the resulting fused and uniform aggregates which exhibit no recognisable individual cells under the light microscope, remain stable, even after the alternating electric field has been switched off or after haemolysis in response to osmotic shock. The fused aggregates are highly elastic. If the field strength of the applied alternating electric field is further increased they are stretched in the direction of the opposite electrode. Frequently, bridges are formed between the two electrodes. The uniform bridges remain stable for some time even in the absence of an electric field. The possibility of cell fusion and its initiation by electrical breakdown of the cell membranes are discussed.
A Hormonal Component in Central Vestibular Compensation
Authors: Horn Eberhard , Rayer Brigitte
Published: August 2018

In developing clawed toads Xenopus laevis, the compensation mechanism of behavioural defects caused by unilateral labyrinthectomy consists of two components, a vestibular one and a hormonal one. Thyroxine accelerates this compensation.
Paramagnetic Species in β-Thalassemic Sera: an ESR Study
Authors: Cannistraro S. , Indovina P. L. , Sportelli L.
Published: August 2018

Homozygous beta thalassemic sera show an electron spin resonance (ESR) signal at g ≃ 6 which is not present in normal and heterozygous sera. The signal arises from high spin heme groups exhibiting a departure from tetragonal symmetry toward rhombic. Binding by a serum protein is very likely responsible for such a distortion. In contrast with other authors’ findings, we report that heme-human albumin complex shows a similar rhombic distortion.

The observed ESR signal at g ≃ 6 is then attributed to this complex.
Plant NAD-Dependent Glutamate Dehydrogenase. Purification, Molecular Properties and Metal Ion Activation of the Enzymes from Lemna minor and Pisum sativum
Authors: Scheid Heinz-Walter , Ehmke Adelheid , Hartmann Thomas
Published: August 2018

Glutamate dehydrogenase (ʟ-glutamate: NAD+ oxidoreductase (deaminating) EC 1.4.1.2) has been purified to homogeneity from Lemna minor and seeds of Pisum sativum. As established by polyacrylamide gel electrophoresis the Pisum-enzyme constitutes a multiple pattern of seven char­ge isoenzymes whereas the Lemna enzyme shows one single protein band. Molecular weights of 230 000 were calculated for both enzymes by sedimentation equilibrium measurements (Pisum-enzyme) and comparative gel filtration (Lemna-enzyme). Sodium dodecyl sulfate gel electrophoresis and electron microscopic observations revealed that both enzymes are composed of four identical subunits (molecular weight 58 500) arranged in a tetraedric structure. The amino acid compositions of both enzymes are similar to those of various hexameric glutamate dehydrogenases. The N-terminal amino acid of the Pisum-enzyme is alanine. Both enzymes require Ca2+ for maximal catalytic activity. For the Lemna-enzyme the K0.5 values for Ca2+ are 22 µᴍ (NADH-dependent reaction) and 4 µᴍ (NAD+ -dependent reaction), respectively. Ca2+ which to some extent can be replaced by Zn2+ does not affect the enzyme aggregation but seems to govern a reversible equilibrium between catalytically active and inactive enzyme forms.
Flavonoids and Related Compounds in Leaves of Pinaceae, IV.
Authors: Genderen H. H. van , Schaik J. van
Published: August 2018

Several flavonoids were isolated from needles of Cedrus deodara. Among them were the 3-glucosides of kaempferol, isorhamnetin and syringetin. Apigenin-7-glucoside and presumably an alkylkaempferol-3-diglucoside were also present. Kaempferol-3-glucoside occurred both free and acylated with p-coumaric acid and/or ferulic acid.
The Regeneration of Virus-Free Plants from Cucumber Mosaic Virus- and Potato Virus Y-Infected Tobacco Explants Cultured in the Presence of Virazole
Authors: Cassells Alan C. , Long Roger D.
Published: August 2018

Adventitious shoots regenerated from tobacco explants taken from donor-plants infected with cucumber mosaic virus and potato virus Y, were virus infected. Similar ex-plants cultured in the presence of Virazole were virus-free.
31P-und 1H-NMR-Untersuchungen über die Wechselwirkung von ATP mit Mg2+, Ca2+ und Monoaminen / 31P-and 1H-NM R-Investigations about the Interaction of ATP with Mg2+, Ca2+, and Monoamines
Authors: Sapper Helmut , Gohl Wolfgang , Lohmann Wolfgang
Published: August 2018

The interaction between aromatic amines and ATP is based upon an electrostatic attraction of the protonated amino groups to the negatively charged phosphate groups of ATP combined with a stacking association between the ring systems. The complexes formed are relatively weak (asociation constants 4-48 M-1), shortlived (life time smaller than 0.02 s), and mainly 1:1 in stoichiometry preferring the terminal phosphate of ATP as the site of association. The divalent metal ions Mg2+ and Ca2+ bond stronger than the amines (association constants 1500 and 100 M-1, resp.) prefer the β-phosphate group changing thereby the geometry of the ATP phosphate chain. Thus, they reduce the amine-ATP association in ternary mixtures.
Über die quantitative fluorometrische Bestimmung von DNA mit Ethidiumbromid in der Zelle und die Konstanz der Quantenausbeute des Ethidium-DNA-Komplexes im biologischen Milieu / On the Quantitative Fluorometric Determination of Cellular DNA by Ethidium Bromide and the Constancy of the Quantum Yield of the Ethidium -DNA -Complex in the Biological Environment
Authors: Pauluhn Jürgen , Naujok Annemarie , Zimmermann Herbert W.
Published: August 2018

The fluorescent staining of fixed A9 cells (mouse fibroblasts) with ethidium bromide E has been investigated qualitatively and quantitatively. E is bound to DNA, RNA and protein. After enzymatic RNA digestion and staining at pH = 4.0 the dyestuff is bound to DNA specifically. The formed E-DNA-complex is stoichiometric if DNA will be saturated by high dye concentra­tion, CF= 1.0 × 10-2 ᴍ. The stoichiometric factor n = 0.21 was determined from Scatchard bind­ing isotherms and by spectrophotometric titration.

The binding of E to DNA and RNA has been investigated by binding isotherms. E is bound to DNA by intercalation and by ionic interaction. It is bound to RNA by ionic interaction only. The ionically bound dyestuff can be replaced by salts like LiCl from DNA and RNA. Only inter­calated E remains. The competitive salt effect can be used to avoid the enzymatic RNA digestion in the specific staining of DNA.

Within the cell the E-DNA-complex fluoresces strongly. Using a microspectrophotometer we determined the fluorescence intensity J and the extinction E in cell sections of q = 1 μ2 area. The fluorescence was excited in the minimum of the absorbance of the E-DNA-complex at λ1 = 365 nm. The extinction E2 was measured in the short wavelength band at λ2 = 260 nm. Under these conditions we received a linear relation J = J(E2) up to high extinctions E2. The quantum yield Q of the E-DNA-complex is nearly constant and independent of the biological environment. Q is also unaltered by LiCl. Within the limits of error intercalated and ionic bound dye have the same quantum yield. Under the conditions of stoichiometric staining the amount of E-DNA- complex and therefore DNA in the cell can be determined by J.

The extinction coefficient Ɛ2 = 45200 ᴍ-1 cm-1 of the E-DNA-complex at 260 nm was calcu­lated from the concentration dependence of the absorbance spectra using the law of mass action. By Ɛ2 the amount of DNA in the cell is accessible from J. According to our measurements with A9 cells the superficial density of DNA has the order of magnitude ρɴ= mɴ/q = 101 nmol cm-2, the amount mɴ of DNA per section q=1 μ2, mɴ = 10-1 fmol, and the DNA concentration in the cell nucleus Cɴ = 10_1 ᴍ. The ray pass and diagram of electronics of the used microspectrophotometer are described.
Einbau von [32P]Orthophosphat in DNA der Mäuse-Milz unter Antigen-Einfluß / Incorporation of [32P]Orthophosphate into DNA of the Mouse Spleen under Influence of Antigen
Authors: Uecker Wilhelm , Kubsch Diethard , Lutz Dieter , Kröger Hans
Published: August 2018

Antigens cause an increase of the DNA synthesis in the spleen of mice as shown by the in­corporation of [32P]orthophosphate and [3H]thymidine. In the present paper, the incorporation of [32P]orthophosphate into the single deoxymononucleotides has been studied under influence of the antigen bovine serum albumin. For this purpose, the labelled DNA was decomposed to the deoxymononucleotides and their specific activities determined. Using [32P]orthophosphate, it was found that the activity of the DNA increased continuously during an observation period of 8 h. While after one hour the relative specific activity of dTMP was highest and that of dAMP lowest, the relative specific activities of the deoxymononucleotides had become equal after 8 h. Under the influence of bovine serum albumin, the incorporation of [32P]orthophosphate increased in the main band DNA as well as in the satellite DNA. The antigen had no effect on the distribution of the specific activities of the deoxymononucleotides.
Die Beziehung der enzymatischen Methylierung invers repetitiver DNA Sequenzen zur Transkription in Maus P815 Mastocytoma Zellen / The Relation of Enzymatic Methylation of Inverted DNA Repeats to Transcription in Mouse P815 Mastocytoma Cells
Authors: Boehm Thomas L. J. , Drahovsky Dusan
Published: August 2018

The isolation of transcribed DNA sequences of P815 cells and the partial characterization with respect to their sequence composition and relative rates of enzymatic DNA methylation are reported in this paper. Transcribed regions were purified by affinity chromatography using im­mobilized heterogenous nuclear RNA of P815 cells. About 10% of total genome was found in this fraction. Reassociation analyses showed differences in sequence composition of transcribed versus non-transcribed DNA fractions. The relative proportion of inverted repeats was doubled in the transcribed fraction whereas ordinary highly repetitive sequences comprising mainly of satellite DNA were found almost exclusively in the non-transcribed regions of the P815 genome. About 70% of transcribed portions corresponds to unique and intermediary DNA sequences. After labelling of cells with L-[Methyl-3H]methionine and [14C]deoxycytidine relative rates of enzymatic DNA methylation were computed for different kinetic components of transcribed and non- transcribed portions of P815 genome. No difference was found except in inverted repeats. In transcribed DNA the relative rate of enzymatic DNA methylation was only about 40% of that of the non-transcribed ones. We have quantitated this hypomethylation and found that there is, in average, about one 5-methylcytosine residue in 100 nucleotides of transcribed inverted repeats, compared to about 2.5 5-methylcytosines in non-transcribed fractions. In view of these data we propose that the enzymatic methylation of inverted DNA repeats negatively controls the tran­scriptional process in a given genomic region.
Oral Cleansing in Spiders is Gland Mediated!
Authors: Sittertz-Bhatkar Helga
Published: August 2018

Histochemical and micromorphological investigations of the gnathocoxal gland in spiders brought out its uniquely adaptive cleansing function. The prey particulates, caught in the oral mi­ crostructures, are bound with mucopolysaccharides or glyco-muco-proteins from the glandular secretions in Araneus and Theridion species into a bolus, and are expelled following each food up­ take.
Umbelliferone in Needles of Picea abies *
Authors: Esterbauer Hermann , Schwarzl Elisabeth , Grill Dieter
Published: August 2018

A compound showing blue fluorescence under UV-light was isolated from spruce needles and identified as umbelliferone. Structure analysis was based on UV and mass spectroscopy as well as chromatographic comparison with authentic material. Quantitative evaluation by direct measurement of the fluorescence of the umbelliferone spot separated by TLC revealed that the umbelliferone content shows great variation within different individual trees ranging from 0.42-42 (μg/g fresh weight. Only minute amounts are present as free umbelliferone while the abundant part is present as β-glucoside.
A Series of Novel Flavanones from Fern Exudates
Authors: Wollenweber Eckhard , Dietz Volker H. , Schillo Detlef , Schilling Gerhard
Published: August 2018

The white farinose exudate on the fronds of Cheilanthes argentea contains a series of flavanones as minor constituents. These were identified by spectroscopic methods as: 5,4′-diOH,6,7-diOMe flavanone and its 4′-OMe derivative, 5,4′-diOH,7,8-diOMe flavanone and its 4′-OMe derivative, 5,6-diOH,7,8,4′-triOMe flavanone, 5,4′-diOH, 6,7,8-triOMe flavanone and its 4′-OMe derivative. The farina of Notholaena limitanea var. mexicana contains eriodictyol-7,4′-di-methyl ether and eriodictyol-7,3′, 4′-trimethyl ether as minor components. Both compounds were also identified in the exudate of N. fendleri, together with naringenin-7-OMe and naringenin-4′-OMe. In N. lemmonii var. lemmonii trace amounts of 5-OH,7,3′,4′,5′-tetra-OMe flavanone were detected. Nine of these substances are novel natural flavanones.
Isolierung und Charakterisierung einer Acetylester-Hydrolase aus Aspergillus rtiger / Isolation and Characterization of an Acetylester-Hydrolase from Aspergillus niger
Authors: Schöbel B. , Pollmann W.
Published: August 2018

The characteristic features of an acetic acid esters hydrolyzing enzyme (acetylesterase, EC 3.1.1.16) are described. The pH- and temperature optimum were 7.0 and 40 °C respectively. The stability of the enzyme regarding different pH- and temperature conditions was investigated. The molecular weight of the acetylesterase could be determined to 160000. A small acetic ester hydrolyzing activity was found too with a molecular weight of about 25000. The activity was not inhibited by addition of di-isopropylphosphorofluoridate (DFP) or physostigmine. The KM-value for glyceryl triacetate was about 90 mM. Concentration of the enzyme was done by ultrafiltration and column-chromatography. The enzymatic activity tests were performed titrimetrically using glyceryl triacetate for substrate.
Effects of Vanadate on the Molybdoproteins Xanthine Oxidase and Nitrate Reductase: Kinetic Evidence for Multiple Site Interaction
Authors: Ramadoss Candadai S.
Published: August 2018

The inhibition of the activity of xanthine oxidase by vanadate was strikingly similar to vanadate inhibition of another molybdoprotein nitrate reductase. Although the main catalytic activity of both enzymes was inhibited, the partial NADH oxidase activity associated with these enzymes was stimulated several fold. It appears that the metal ion binds at multiple site in both enzymes. In the absence of any enzymes a combination of vanadium (V) and molybdenum (V) in air was found to oxide NADH rapidly.
Untersuchungen über Pherom one bei Formica polyctena (Förster) / Studies on the Pheromones of Formica polyctena (Förster)
Authors: Francke W. , Bühring M. , Horstmann K.
Published: August 2018

Methyl-3-isopropylpentanoate is identified from the heads of workers and in higher concentration from heads of old queens of Formica polyctena (Förster). In laboratory bioassays this terpenoid ester showed a strong aggression inhibiting effect. While in the abdomina of workers the alarm pheromone undecane is the main compound it is almost completely absent in the abdomina of old queens.
Chlorophyll Biosynthesis: Various Chlorophyllides as Exogenous Substrates for Chlorophyll Synthetase
Authors: Benz Jürgen , Rüdiger Wolfhart
Published: August 2018

The esterification of various chlorophyllides with geranylgeranyl diphosphate was investigated as catalyzed by the enzyme chlorophyll synthetase. The enzyme source was an etioplast membrane fraction from etiolated oat seedlings (Avena sativa L.). The following chlorophyllides were prepared from the corresponding chlorophylls by the chlorophyllase reaction: chlorophyllide a (2) and b (4), bacteriochlorophyllide a (5), 3-acetyl-3-devinylchlorophyllide a (6), and pyrochlorophyllide a (7). The substrates were solubilized with cholate which reproducibly reduced the activity of chlorophyll synthetase by 40-50% . It was found that the following compounds were good substrates for chlorophyll synthetase: chlorophyllide a and b, 3-acetyl-3-devinylchloro-phyllide a, and pyrochlorophyllide a. Only a poor or no reaction was found with protochloro­phyllide, pheophorbide a, and bacteriochlorophyllide. This difference of reactivity was not due to distribution differences of the substrates between solution and pelletable membrane fraction. Furthermore, no interference between good and poor substrate was detected. Structural features necessary for chlorophyll synthetase substrates were discussed.
Initiation of Protein Synthesis in Yeast: Binding of Met-tRNAi
Authors: Kreutzfeldt Christian
Published: August 2018

Conditions for the binding of Met-tRNAi to 40 s ribosomal subunits and to proteins isolated out of the yeast ribosomal KCl wash were investigated. Sucrose density gradient experiments revealed that binding of Met-tRNAi to 40 s ribosomal subunits was catalyzed in a AUG and GTP dependent reaction. Binding of Met-tRNAi to proteins of the ribosomal KCl wash as assayed by the Millipore filter technique was found to be independent of AUG, GTP and 40 s ribosomal subunits. Additions of GTP yielded only slight stimulation, whereas Mg2+ caused dissociation of complexes. It was concluded that these reactions were most likely catalyzed by initiation factor eIF-2 although stimulation by GTP did not occur.
Molekulare und kinetische Charakterisierung der Xanthin-Dehydrogenase aus dem phototrophen Bakterium Rhodopseudomonas capsulata / Molecular and Kinetic Characterization of Xanthine Dehydrogenase from the Phototrophic Bacterium Rhodopseudomonas capsulata
Authors: Aretz Werner , Kaspari Herwig , Klemme Jobst-Heinrich
Published: August 2018

The structural and kinetic properties of xanthine dehydrogenase (EC 1.2.1.37) from the facultative phototrophic bacterium Rhodopseudomonas capsulata were studied. The enzyme was fully induced when hypoxanthine or xanthine, but less effectively when uric acid served as nitrogen source during growth. The enzyme was purified about 2300-fold from cells grown photosynthetically with hypoxanthine as N-source by using ammoniumsulfate precipitation, gel filtration, ion-exchange and affinity chromatography. The molecular weight as determined by gel filtration throug Sephacryl S-300 was 345000. Subunit analysis by sodium dodecyl sulfate gel electrophoresis suggested a composition of four identical subunits with a molecular weight of 84000. The enzyme contained 2 flavin, 2 molybdenum and 8 iron-sulfur groups per mol. The turnover number with hypoxanthine and NAD as substrates was 12000 min-1. Hypoxanthine, 1-methylhypoxanthine, 8-azahypoxanthine, xanthine, 1-methylxanthine, 2-hydroxypurine, 6,8-di-hydroxypurine, 5-azacytosine and 5-azauracil served as electron donors. The most effective electron acceptor was NAD. The kinetic constants (Km) were (in μm): 52.5 (hypoxanthine); 32.5 (xanthine) and 61.2 (NAD). Various purine compounds inhibited the enzyme competitively in respect to hypoxanthine as substrate. Although reduction of uric acid to xanthine was not detected by using purified enzyme preparations, in vitro-experiments with 14C-labelled uric acid indicated that the enzyme xanthine dehydrogenase participates in uric acid degradation in Rps. capsulata. According to their electrophoretic mobilities, the xanthine dehydrogenases isolated from hypoxanthine-and uric acid-grown cells were identical.
Altered Heme Environments in Opossum and Rabbit Methemoglobins
Authors: John Maliyakal E. , DuBois Raymond N. , Waterman Michael R.
Published: August 2018

The effect of pH and inositol hexaphosphate (IHP) on the symmetry of the heme environments in opossum (Didelphius marsupialis) and New Zealand White rabbit hemoglobins has been studied using electron spin resonance (ESR). Each methemoglobin is found to contain two different heme environments as detected by the rhombicity observed in the ESR spectrum. In both cases the rhombic nature of the ESR spectrum is influenced by pH and IHP binding, although in the case of rabbit methemoglobin the high spin ESR signal disappears above pH 8.0. In both hemoglobins, amino acid alterations in the α-chains are known to affect the properties of the ferrous derivatives. It is concluded that these alterations also provide the basis for the ESR spectral properties observed with the methemoglobins.
A H+/Ca2+ Antiporter in Membranes of Microsomal Vesicles from Maize Coleoptiles, a Secondary Energized Ca2+ Pump
Authors: Hager A. , Hermsdorf P.
Published: August 2018

Microsomal vesicles prepared from the ER and the Golgi apparatus of maize coleoptiles possess an ATP-fueled, Cl--dependent proton pump which can cause an intravesicular acidifica­tion of the vesicles (A. Hager and M. Helmle, Z. Naturforsch. 36 c, 997 (1981); A. Hager et al., Z. Naturforsch. 35 c, 783-793 (1980)). This acidification is very specifically inhibited by Ca2+. The inhibition is already distinct at concentrations of 30 μᴍ. While 10-fold higher concentrations of La3+ produce similar effects, Mg2+ remains ineffective even at very high concentrations.

If Ca2+ is added after acidification of the vesicles, a rapid H+-efflux proportional to the amount of Ca2+ added characterizes the first reaction phase. In the second reaction phase acidification within the vesicles commences anew, however, at a reduced rate.

If Ca2+ is added to vesicles whose proton pump has been inhibited by DCCD, the first reaction phase remains unchanged, while the acidification in the second reaction phase does not set in, and only a leak out of protons is observed.

These results give support for a H+/Ca2+-antiporter mechanism which can function as a secondary energized Ca2+-pump and regulate the Ca2+-concentration in the cytoplasm.
Comparative Binding of Photosystem II — Herbicides to Isolated Thylakoid Membranes and Intact Green Algae
Authors: Laasch Henrik , Pfister Klaus , Urbach Wolfgang
Published: August 2018

The binding of the photosystem II herbicides diuron (DCMU), atrazine (s-triazine), ioxynil and dinoseb (substituted phenols) to isolated spinach thylakoids was saturated in less than 2 min in the dark. In intact cells of the green alga Ankistrodesmus b. it took 10 to 20 min to reach the binding equilibrium.

Binding affinity of diuron, atrazine, dinoseb, measured as equilibrium binding constants, was found to be comparable in isolated thylakoids and intact algal cells. For ioxynil, reduced binding affinity was observed in algae.

The concentration of binding sites in thylakoids and intact cells was determined to be 300-500 chl/inhibitor binding site, suggesting a 1:1 stoichiometry between bound herbicide and electron transport chains. In intact cells only the phenol herbicides ioxynil and dinoseb showed increased concentrations of binding sites.

Strong correlation of herbicide binding and inhibition of electron transport was found for diuron in isolated thylakoids and intact cells. In thylakoids this is valid also for atrazine and dinoseb. For ioxynil a difference between the amount of binding and inhibition was found. This correlation of herbicide binding and inhibition proves that binding specifically occurs at the inhibition site at photosystem H.

In addition to the specific binding, for all four herbicides studied, (except for ioxynil in thylakoids) unspecific binding was observed in thylakoids as well as in algae, which was not related to inhibition.
Effect of Lithium Chloride on the Circadian Rhythm in the Flight Activity of the Microchiropteran Bat, Taphozous melanopogon
Authors: Subbaraj Ramanujam
Published: August 2018

We have performed experiments on the influence of Li+ offered through drinking water i) on the period length (τ) of the rhythm in the flight activity of bats under LL and ii) on phase angles during entrainment under LD cycles. Bats subject to entrainment exhibited no qualitative and quantitative change in Ψ values after Li+ treatment. In contrast the ingestion of Li ions by bats under free-running conditions shortens the τ of the bat rhythm by an amount that is a function of period length prior to ingestion, τ is, thus homeostatically conserved in the face of Li administra­ tion in bats.
"Yellow Flavonols" as Components of Pollen Pigmentation
Authors: Wiermann Rolf , Wollenweber Eckhard , Rehse Cornelia
Published: August 2018

Yellow coloration of pollen in some exceptional cases can be caused by the presence of intensely coloured flavonoids. Derivatives of herbacetin (sexangularetin) and of gossypetin (limocitrin) have been found as “yellow flavonols” in the pollen of some species of Paeonia and of Rumex. The pollen of Spinacea oleracea contains the 6-methyl ether of galetin and the quercetagetin derivatives patuletin and spinacetin
Sinapine as a Supply of Choline for the Biosynthesis of Phosphatidylcholine in Raphanus sativus Seedlings
Authors: Strack Dieter
Published: August 2018

Biosynthesis of phosphatidylcholine in young seedlings of Raphanus sativus is supplied with choline from degradation of the seed constituent sinapine (sinapoylcholine). This conclusion has been deduced from the following results:

(1) Raphanus sativus seedlings accumulate approx. 70 nmol phosphatidylcholine which may be relevant for the consumption of choline, liberated during hydrolysis of approx. 130 nmol sinapine.

(2) [14C]choline and [14C]ethanolamine, taken up by germinating Raphanus seeds, are exclusively consumed in the biosynthesis of phosphatidylcholine and phosphatidylethanolamine, respectively.

(3) Pulse-chase experiments with seedlings at different germination stages show a reduced [14C]choline incorporation into phosphatidylcholine at the time when degradation of sinapine occurs, obviously as a result of an isotope dilution by an increase of the endogenous choline pool.

(4) After [14C]choline pulse to immature seeds, during the process of seed maturation most of the activity taken up is incorporated into accumulating sinapine and approx. 50% compared to this into phosphatidylcholine. During seedling development the quantity of labelled sinapine rapidly decreases as a result of sinapine degradation with a concomitant label increase in free choline, phosphorylcholine, and phosphatidylcholine. Approx. 50% of the choline liberated from sinapine, is consumed in the biosynthesis of phosphatidylcholine.

High performance liquid chromatographic analyses of phosphatidylcholine during Raphanus germination revealed that this phospholipid might be a metabolically active compound. Changes in the absorptivity of this compound at 210 nm indicate changes in the degree of unsaturation in the fatty acyl groups
Synthesis and Biological Activity of Aminomethylphosphonic Acids Related to the Herbicide Glyphosate
Authors: Fredericks Peter M. , Summers Lindsay A.
Published: August 2018

Several aminomethylphosphonic acids related to the herbicide glyphosate have been synthesised and their post-emergent herbicidal properties studied
Isolation and Identification of an Oxygen Reducing Factor (ORF) from Isolated Spinach Choloroplast Lamellae
Authors: Firl J. , Frommeyer D. , Elstner E. F.
Published: August 2018

From the water extracts of heat-treated spinach chloroplast lamellae, five compounds were isolated by column chromatography and identified by paper chromatography, UV-, IR-, 1H-NMR- and 13C-NMR spectrometry: besides the major component, sucrose, 1 glyophilized material contained 197 mg oxalic acid, 4.6 mg uridine and uracil and 22 μg lumiflavin. Only the isolated lumiflavin stimulated photosynthetic oxygen reduction and H2O2 production by illuminated chloroplast lamellae. Evidence is presented that the stimulation of photosynthetic oxygen activation by water extracts of heat-treated chloroplast lamellae is most likely due to flavin derivative(s) (probably FAD) released from thylakoid-bound ferredoxin-NADP reductase by heat- and other treatments. Lumiflavin is artifactually derived from the solubilized flavin coenzymes during the isolation procedure
Physico-Chemical Characteristics of DNA Chromatin Fractions from Calf Thymus
Authors: Gawrońska Maria , Kulamowicz Irena , Oliński Ryszard , Żbikowska Małgorzata , Walter Zofia
Published: August 2018

Two DNA fractions with different physico-chemical properties were obtained from calf thymus. On the basis of our results as well as some literature data we suppose that these are eu-and heterochromatin DNAs.
Flavonoidglycoside und Pyrone bei Aniba-Arten (Lauraceae) / Flavonoid Glycosides and Pyrones in Aniba Species (Lauraceae)
Authors: Koch V. , König W. A.
Published: August 2018

The distribution of flavonoid glycosides and pyrones are investigated for 3 Aniba species. The intraspecific variation of these compounds is shown for Aniba rosaeodora. 6-(3′,4′-methylendioxy-trans-styryl)-2-pyrone and 6-(3′,4′-dimethoxy-trans-styryl)-2-pyrone are seldom occuring natural compounds and were proved for A. permollis for the first time. The phylogenetic aspects are briefly discussed.
Coα/Coβ-Isomerie der am Kobalt methylierten Corrinoide. Über die CD-und ORD-Spektren einiger Isomerenpaare / Coα/Coβ-Isomerism of the Cobalt Methylated Corrinoids. CD and ORD Spectra of Several Isomer Pairs
Authors: Moskophidis Matthäus
Published: August 2018

The CD and ORD spectra of the Coar-and Co/β-methyl isomers of cobalamin, 2-methylthio-adenyl cobamide (factor S), cobyric acid and p-kresyl cobamide (factor lb) were recorded in water and acidic solution. In complete and incomplete (nucleotide free) (Coar-methyl)-corrinoids the axial ligands CH3 and H2O are unalterable (fixed) within a wide range of pH (about 1 to 12) at room temperature in the dark. Thus the spectra in this pH range are constant at X > 350 nm; spectral differences at X < 350 nm are effects of the nucleotide bases. The spectra of complete "base-on" (Co/β-methyl)-corrinoids are, like the spectra of (Coa-methyl)-corrinoids, at X > 350 nm not dependent on the nucleotide base. If the nucleotide base is not coordinated ("base-off'), the spectra change strikingly and at X > 350 nm are nearly identical with those of incomplete corrinoids e. g. cobyric acid.
Halbseiten-Reaktivität der Glycerinaldehyd-3-phosphat Dehydrogenase aus Kaninchen-Skelettmuskel mit Strukturanalogen von NAD / Half-of-the-Sites Reactivity of Glyceraldehyde-3 Phosphate Dehydrogenase from Rabbit Muscle with Structural Analogs of NAD
Authors: Ehrenfeld Michael , Jeck Reinhard , Klatte Walter , Kühn Norbert , Woenckhaus Christoph
Published: August 2018

Alkylating NAD-Analogs, Glyceraldehyde-3 Phosphate Dehydrogenase, Half-of-the-Sites Reactivity co-(3-Bromoacetylpyridinio)alkyldiphosphoadenosines with alkyl chain lengths of 2 -6 me­ thylene groups inactivate glyceraldehyde-3 phosphate dehydrogenase from rabbit muscle. Half-of-the-Sites reactivity is observed in each case: The analogs are covalently bound to highly reactive cysteine residues in two of the four subunits. The remaining two subunits still bind N AD and the reactive SH-groups, although modified by SH-reagents of low molecular weight are not labeled by any of the brominated coenzyme models. This behaviour may be explained by the assumption, that the modification of 2 subunits induces structural changes in the neighboured unoccupied subunits which prevent any attack on reactive cysteine residues caused by fixation and orientation of the bromoketo-coenzyme analog when bound to the active center. Structural similarities of the covalently bound coenzyme analogs in the active center and the native ternary GAPDH-NAD-substrate complex suggest that half-of-the-sites reactivity is a natural characteristic of the enzymes catalytic mechanism.
DNA Content and Fragmentation of the Egg Nucleus of Trichoplax adhaerens
Authors: Ruthmann A. , Grell K. G. , Benwitz G.
Published: August 2018

Under culture conditions the egg nucleus of Trichoplax adhaerens reaches an unusually high and variable DNA content. Before the "fertilization membrane" is formed, the nucleus undergoes fragmentation. It is assumed that culture conditions differ from natural conditions by preventing the switch-over from the S-phase to the G 2-phase of the cell cycle: DNA replication continues and nuclear division is impossible. Cleavage ceases at an earlier or later stage.
Intracelluläre Wirkung von Hydroxyalkenalen auf tierische Tumoren / Intracellular Effect of Hydroxyalkenals on Animal Tumors
Authors: Khoschsorur G. , Schaur R. J. , Schauenstein E. , Tillian H. M. , Reiter M.
Published: August 2018

When incubated for 30 min in vitro, 4-hydroxyalkenals in a 5 x 1 0 ~ 3 m solution react with SH-groups of soluble cytoplasmic and nuclear proteins (ProtL-SH) of Morris hepatomas 9618 A and 5123 tc, and of Ehrlich ascites tumor (EAT) cells. The extent of the reaction strongly increases with decreasing doubling time of the respective tumors. Former experiments with EAT cells have shown that the reaction with cytoplasmic ProtL-SH causes inhibition of respiration, glycolysis, and probably of other SH-controlled processes associated with cell division. The intranuclear reaction leads to an inhibition of DNA-and RNA-synthesis. In a 2 x 10-4 M solution of hydroxyalkenals, however, the reaction with cytoplasmic ProtL-SH diminishes almost completely so that no mea­ surable inhibition of respiration and only 3% inhibition of glycolysis are observed, while 20 to 30 percent of the nuclear ProtL-SH are still blocked. This corresponds well with a previous obser­ vation that a 2 x 10-4 m solution of hydroxypentenal inhibits DNA-synthesis by 90 percent.
In vivo Evidence for a Functional Glycolytic Compartment in Synchronous Yeast Cells
Authors: Postius Stefan
Published: August 2018

The different metabolic behaviour of endogenously produced [1-14C] pyruvate derived from [3,4-14C]glucose and of exogenously added [1-14C]pyruvate were studied with synchronous yeast cell populations, under conditions which differentially influenced the activities of pyruvate decarboxylase in the cytoplasm and pyruvate dehydrogenase in the mitochondria. Endogenously produced [1-14C]pyruvate is decarboxylated almost exclusively by PDC under anaerobic condi­ tions, in contrast to added [1-14C]pyruvate which is decarboxylated under aerobic conditions by the action of PDH mainly. Whereas 14CO 2 evolution from exogenous [l-14C]pyruvate can be diluted proportionally by addition of pyruvate, this is not the case for 14CO 2 evolution from endogenous [1-14C]pyruvate. It is suggested that glycolysis or at least some constituents of it might be arranged in such a manner that the resulting complex behaves as a functional compartment, meaning that it is almost inaccessible to exogenously added pyruvate.
Iridoide aus Clerodendrum thomsonae Balf. f., Verbenaceae / Iridoids in Clerodendrum thomsonae Balf. f., Verbenaceae
Authors: Lammel Gabriele , Rimpler Horst
Published: August 2018

Iridoids, 8-O-Acetylmioporosid, Clerodendrum, NMR, MS Clerodendrum thomsonae Balf. f. has been examined for iridoids. Besides the known compounds melittoside, aucubin, 8-O-acetylharpagide, reptoside and ajugoside a new iridoid, 8-O-acetylmioporoside, has been isolated using SC and HPLC. The structure and relative configuration of the new compound have been determined by spectroscopic methods (1H-NMR, 13C-NMR, MS) and by correlation with mioporoside.
The Effect of Clotrimazole and Triadimefon on 3-Hydroxy-3-Methyl-Glutaryl-CoA-Reductase-[EC 1.1.1.341]- Activity in Saccharomyces cerevisiae
Authors: Berg Dieter , Draber Wilfried , Hugo Hasso von , Hummel Werner , Mayer Dieter
Published: August 2018

Clotrimazole and triadimefon are known as potent inhibitors of ergosterol synthesis in pathogenic yeasts and fungi, respectively. As their mode of action generally the inhibition of sterol desmethylation reactions is accepted. We report about a second effect, a "feed-back" inhibition of 3-hydroxy-3-methyl-glutaryl (HMG)-CoA-reductase by accumulation of ergosterol precursors. Addition of lanosterol to intact cells leads to an inhibition of HMG-CoA-reductase as well, but not to fungistatic effects. From the reported data the influences of clotrimazole and triadimefon have to be considered as an inhibition of desmethylation reactions involved in ergosterol synthesis of yeasts and fungi with a concomitant decreased production of mevalonate.
Ascorbate Oxidase and Its Possible Involvement in Cancer
Authors: Lohmann Wolfgang
Published: August 2018

The electron spin resonance (ESR) spectrum of erythrocytes of a healthy male volunteer exhibited 2 min after intravenous administration of 1 g of ascorbic acid a considerable increase in spin concentration and a new signal at about g = 2.005 which we previously had found to correlate to the semidehydroascorbate (SDA) radical and which is not identical with the O j radical. Moreover, the vitamin C concentration in erythrocytes and plasma was considerably higher than in comparable samples of other volunteers treated identically. In the latter cases, the ESR spectrum of the erythrocytes was not modified at all. These findings suggest that there must be a substance which reacts with ascorbic acid specifically. It can be assumed that the enzyme ascorbate oxidase plays this decisive role in the ascorbic acid metabolism. For this reason, different amounts of ascorbate oxidase have been added to healthy erythrocytes treated in vitro with ascorbic acid and to tissue samples of lung cancer. As expected, the vitamin C effect as expressed by the appearance of the SDA signal and the increase in spin concentration could be reversed. It is suggested, therefore, that in special types of cancer, such as acute lymphatic leukemia and lung cancer, the concentration of ascorbate oxidase or of an enzyme acting like it is, primarily, diminished, while in other types it might be enlarged.
Hydrogen-Deuterium Exchange in Adenosine 5'-Monophosphate Detected by Surface Enhanced Raman Scattering (SERS)
Authors: Koglin E. , Séquaris J. M. , Valenta P.
Published: August 2018

The enhanced Raman effect from 5'-AMP adsorbed on the roughened silver surface is used to characterize hydrogen-deuterium exchange. SERS spectra of 5'-AMP present in H2O and D2O solutions at rather low concentrations were recorded in the spectral range of 2000 to 3500 cm-1. Surface enhanced Raman bands in this spectral range are found to increase in intensity, relative to bands of normal Raman solution spectra. In addition, one notes that the CH and CD stretching vibrations, almost obscured by H2O2 or D2O scattering, now stand out clearly.
Effect of Lectins and Chemical Modification on the Hemagglutinin Activity of Human Plasma Fibronectin
Authors: Vuento Matti , Salonen Eija
Published: August 2018

Purified hum an plasm a fibronectin has been shown to agglutinate protease-treated red cells [Vuento, Hoppe-Seyler's Z. Physiol. Chem. 360, 1327-1333, (1979)]. The present report shows that the activity is inhibited by low concentrations of lectins and by macrom olecular serum factors. Chemical m odification of carboxyl groups of fibronectin strongly inhibited the activity, but modification of am ino groups or guanidinium groups had little effect on the activity. The results suggest that fibronectin receptors on erythrocyte surface are carbohydrate-containing molecules. Humoral m acrom olecular factors may control the interaction of fibronectin with cell surfaces. Chemical m odification studies indicate that the parts of the fibronectin molecule responsible for the hem agglutinin activity are different from those mediating the binding of fibronectin to collagen.
Red Light Induced Change in the Saponin Content of Prolamellar Bodies in Avena sativa
Authors: Müller Mechthild
Published: August 2018

Exposure to red light of high intensities leads to saponin and prolam ellar body degradation in etiolated Avena sativa seedlings. Exposure to red light of low intensities increases the saponin percentage found in prolam ellar bodies w ithout changing the overall saponin content. Proto­ chlorophyllide is assumed to act a decisive p art in the phototransform ation of the PLB as expressed by their saponin content. This is indicated by the action spectrum of this stim ulation as well as by experiments with long-wave red (729 nm) and A LA /LA treatment. In weak light the pchlide phototransformation is decelerated-probably due to lack of energy. The PLB are inter­ preted to be modified by the increased pchlide concentration so that more saponin can be incorporated.

In further experiments a barley m utant (albina f 17) lacking the capacity to esterify phytol as well as the capacity to degrade the PLB during the greening process was investigated. The results substantiate our hypothesis, as PLB transform ation — indicated by PLB saponin concentration — is decelerated with increasing pchlide concentration in greening etioplasts.
Pannarsäure und Porphyrilsäuremethylester — Sekundärstoffe der Flechtengattung Psoroma / Pannaric Acid and Prophyrilic Acid Methyl Ester Lichen Substances in the Genus Psorma
Authors: Renner B. , Henssen A. , Gerstner E.
Published: August 2018

The novel liehen substance porphyrilic acid methyl ester and pannaric acid are reported the first time in the lichen genus Psoroma. They are constituents in the two varieties of the new species Psoroma tenue as well as in members of the Psoroma hypnorum/paleaceum aggr. and in a hitherto underscribed species from the southern hemisphere. Both dibenzofuranes are characterized by mass spectrometry and UV/VIS spectroscopy. A third compound of unknown structure (Ut) has been found additionally in the two varieties of P. tenue and in some specimens of the P. hypnorum/paleaceum group.
A Simple Coding Procedure Enhances a Neuron's Information Capacity
Authors: Laughlin Simon
Published: August 2018

The contrast-response function of a class of first order intemeurons in the fly's compound eye approximates to the cumulative probability distribution of contrast levels in natural scenes. Elementary information theory shows that this matching enables the neurons to encode contrast fluctuations most efficiently.
Detection of Glyceollin on the Cellular Level in Infected Soybean by Laser Microprobe Mass Analysis
Authors: Moesta P. , Seydel U. , Lindner B. , Grisebach H.
Published: August 2018

Laser microprobe mass analysis was explored as a method for the detection at the cellular level of the phytoalexin glyceollin in soybean cotyledons infected with an incompatible race of Phy- tophthora megasperma f. sp. glycinea. For LAMMA® analysis 10 μm freeze microtome sections which were freeze-dried on copper grids were used. The LAMMA spectrum of glyceollin (isomer I) shows a characteristic peak at m/e = 321 which can be attributed to M-OH+. This peak was also present in the spectra of infected regions from a cotyledon but was completely absent in the spec­tra of uninfected tissue. One hundred and Fifty LAMMA spectra were taken along a line per­pendicular to the border line of infection. A steep rise in glyceollin content toward the infected area was observed. This is the First time that such highly localized glyceollin accumulation has been shown at the cellular level. The results show that LAMMA analysis is suitable for the de­tection of organic molecules in biological tissues with high lateral resolution.
Oxygen-Isotope Effect in Enzymatic Cleavage Reaction of 13-ʟ-Hydroperoxylinoleic Acid to Hexanal and 11-Formyl-cis-9-undecenoic Acid
Authors: Hatanaka Akikazu , Kajiwara Tadahiko , Sekiya Jiro , Fukumoto Takehiko
Published: August 2018

Hydroperoxide lyase E"2 solubilized with Tween 20 from tea chloroplasts was shown to catalyze cleavage reaction of 13-L-hydroperoxy-cis-9,trans-11-octadecadienoic acid (13-ʟ-hydroper- oxylinoleic acid) to hexanal, a C6-compound and 11-formyl-cis-9-undecenoic acid, a C12-compound by identification of cleavage products using authentic specimens synthesized through an unequivocal route. An oxygen-isotope effect was first observed in the cleavage reaction of 18O- labeled 13-ʟ-hydroperoxylinoleic acid by solubilized E2
″. The 18O-atom of hydroperoxide was not detected in carbonyl group of hexanal formed from 18O-labeled 13-ʟ-hydroperoxylinoleic acid.