bluuebunny/crossref_metadata_2025 huggingface dataset:
The Sensitivity Shift Due to Light Adaptation Depending on the Extracellular Calcium Ion Concentration in Limulus Ventral Nerve Photoreceptor
Authors: Stieve H. , Bruns M. , Gaube H.
Published: August 2018

Receptor potentials of Limulus ventral photoreceptors were recorded in two defined states of moderate light- and considerable dark adaptation (LA, DA) by a repeated stimulus sequence consisting of a conditioning 2 s illumination (white light, response saturating intensity) followed by two 10 ms test flashes at fixed intervals evoking LA and DA responses (intensity varied from threshold to saturation of response amplitude). The half saturating intensity I50 was determined from response height vs log stimulus intensity curves for LA and DA, while the photoreceptor was superfused either by reference saline (physiological ion concentrations, including 10 mmol/l Ca2+) or by test salines in which the [Ca2+] was varied between 40 μmol/l and 100 mmol/l. The sensitivity of the dark-adapted receptor does not significantly depend on the [Ca2+]ex, but the sensitivity shift due to LA (measured by /50) is reduced when the [Ca2+]ex is lowered, and augmented when the [Ca2+]ex is increased. Additional reduction of the [Na2+]ex from 463 mmol/l to 46 mmol/l or increase of the [Mg2+]ex from 50 mmol/l to 100 mmol/l does not counteract the effect of lowered [Ca2+]ex on LA. The results confirm the assumption that a transient increase of the intracellular [Ca2+] supplied from extracellular sources during the light response is the main cause for LA This calcium effect on light adaptation is neither characterized by a calcium/sodium antagonism, nor mimicked by magnesium, in contrast to the calcium effect on the gating of the light-activated ion channels.
Causal Relationships among Metabolic Circadian Rhythms in Lemna
Authors: Goto Ken
Published: August 2018

Biochemical aspects of circadian rhythms were studied using a long-day duckweed, Lemna gibba G3 cultured in short day condition (9 h light at 3800 lux followed by 15 h darkness), which was transferred in continuous light (LL) at the end (LL 0) of the last night period. With such a system I have previously reported a rhythm of affinity for NAD+ of cytoplasmic NAD - dependent glyceraldehyde 3-phosphate dehydrogenase (Cyt-NAD -GPD ) 180° out of phase with that of affinity for NADP+ of chloroplastic NADP-dependent GPD (Chl-NADP-GPD ) and that NADP+ could increase in vitro the affinity for NADP+ of Chl-NADP-GPD . I report here that NADP+ can decrease in vitro the affinity for NAD+ of Cyt-NAD -GPD as well, and furthermore, that the in vivo level of NADP+ oscillates in phase with the rhythm of the affinity for NADP+ of Chl-NADP-GPD.

Moreover, I found the existence of mirror-image circadian rhythms, of comparable am plitudes, of in vivo levels of NAD+ + NADH (total NAD) (with peaks, as the ones of Cyt-NAD - GPD. at LL 0 and 24) and of NADP+ + NADPH (total NADP) (with peaks, as the ones of Chl-NADP-GPD, at LL 12 and 36). Consequently, a circadian rhythm in the rate of net in vivo production of total NADP (or NAD) might be expected 90° in advance of that in the level of total NADP (or NAD). Indeed. I found oscillations in the activities of NAD kinase and of NADP phosphatase with peaks occurring, respectively, at LL 6 and at LL 18. Moreover, in vitro treatments with EGTA (a Ca2+-chelator), chlorpromazine and W7 (both inhibitors of calmodulin) were able to both inhibit NAD kinase from its highest level of activity to its minimal one and activate NADP phosphatase from its lowest level of activity to its maximal one. I conclude, therefore, that the in vivo level of Ca2+-calmodulin could oscillate in phase with the rhythm of NAD kinase activity and induce the mirror-image circadian rhythms of activities of NAD kinase and of NADP phosphatase.

I propose that the control sequence among the several circadian rhythms I studied could start with changes in Ca2+-calmodulin, then proceed through oscillations in NAD kinase and NADP phosphatase activities, leading to changes in NAD+, NADP+, and NADPH levels, which would themselves induce the Chl-NADP-GPD and Cyt-NAD -GPD rhythms.
Product Specificity during Incubation of Methyl Linoleate with Soybean Lipoxygenase-I
Authors: Hatanaka Akikazu , Kajiwara Tadahiko , Sekiya Jiro , Asano Masashi
Published: August 2018

Abtract

The ratios of 13:9 isomers of the hydroperoxides produced during incubation of methyl linoleate with soybean lipoxygenase-1 were ca. 50:50 at pH 7.8 and ca. 70:30 at pHs 9.0 and 11.0, respectively. In striking contrast to the lipoxygenase-catalyzed hydroperoxidation of linoleic acid, the hydroperoxidation of methyl linoleate at pH 7.8 gave almost racemic 13-hydroperoxides and that at pHs 9.0 and 11.0 yielded methyl 13-L-hydroperoxylinoleate having low optical purities (L/D, ca. 45/30).
The Chromophore of the Visual Pigment in Some Insect Orders
Authors: Vogt Klaus
Published: August 2018

The chromophore of the visual pigment in different insect orders has been identified. The novel chromophore 3-hydroxy-retinal was found in Diptera and Lepidoptera, while in the other groups investigated retinal is the chromophore of the visual pigment.
Dopamine Accumulation in Papaver somniferum Latex
Authors: Homeyer B. C. , Roberts Margaret F.
Published: August 2018

Organelles found in the 1000 x g fraction of latex taken from Papaver somniferum have been shown to accumulate dopamine to the exclusion of other catecholamines. Dopamine accumula­ tion is both temperature and pH dependent and there is no evident requirement for ATP (1 mᴍ) or Mg2+ (2mᴍ). The relatively high (4.37 mᴍ), specificity of dopamine uptake, and insensitivity to inhibitors distinguish papaver latex organelle dopamine uptake from catecholamine uptake by mammalian chromaffin granules.
Differential Synthesis of Alkaline Phosphatase in Rhizobium Species Isolated from the Tropics
Authors: Singh Akhand P. , Singh J. B.
Published: August 2018

A total of 28 strains of several species of Rhizobium were screened for the presence and regulation of the enzyme alkaline phosphatase. In contrast to all other species of Rhizobium, the activity of this enzyme was absent in R. trifolii. Different levels of alkaline phosphatase were observed in various species of Rhizobium. Both, species as well as strain specific differences were found in the level of alkaline phosphatase.
Fluorescence-ODMR of Reaction Centers of Rhodopseudomonas viridis
Authors: Angerhofer A. , Schütz J. U. von , Wolf H. C.
Published: August 2018

Fluorescence detected ODMR measurements in zero field on the triplet state of the reaction center in whole cells of Rhodopseudomonas viridis, in reaction center solution and in reaction center crystals are reported. In solution and in the crystal a sign reversal of the F-ODMR signals is observed by variation of the wavelength of detection. The signs of the signals are interpreted with the Vredenberg-Duysens relation.
Dependence on Membrane Lipids of the Effect of Vanadate on Calcium and ATP Binding to Sarcoplasmic Reticulum ATPase
Authors: Medda Pankaj , Hasselbach Wilhelm
Published: August 2018

The affinity of the sarcoplasmic reticulum transport ATPase for calcium and ATP is not affected by lipid depriviation while vanadate binding is completely abolished. Lipid substitution restores vanadate binding as well as the vanadate induced disappearance of the enzyme’s high affinity calcium and nucleotide binding sites. Nucleotide binding is simultaneously restored with the displacement of vanadate from the enzyme following the occupation of its low affinity calcium binding sites.
Titer of Juvenile Hormone III in Drosophila hydei during Metamorphosis Determined by GC-MS-MIS
Authors: Bührlen U. , Emmerich H. , Rembold H.
Published: August 2018

The titer of juvenile hormone III (JH-III) has been determined by the use of combined gas chromatography-mass spectroscopy (GC-MS) in whole body extracts of the larvae, prepupae, pupae and adults of Drosophila hydei. A characteristic JH-III titer curve was established by use of the hormone derivatives. No other juvenile hormone homologs were detected.

JH-III shows a broad peak maximum of about 30 pmol/g fresh weight during the last larval instar, whereas only traces of the hormone are detectable at pupariation. Prepupae and pupae exhibit about the same JH-III level. In older pupae and in the pharate adults there was no JH-III detectable but it reappeared soon after emergence. Low values of JH-III are found in young male and female flies. The JH contents rise to distinct peaks in older and reproductive adults, both in male and female animals.
Effect of Extracellular Alkali Metal Salts on the Electric Parameters of Human Erythrocytes in Normal and Pathological Conditions (Homozygous β-Thalassemia)
Authors: Ballario C. , Bonincontro A. , Cametti C. , Rosi A. , Sportelli L.
Published: August 2018

The conductivity of human erythrocyte cells dispersed in various uni-univalent electrolyte solutions (NaCl, KCl, LiCl, CsCl; 0.15 ᴍ) have been measured in the frequency range from 10 KHz to 100 MHz at five temperatures between 5 and 45 °C. The results were analyzed in the light of the theory of conductivity polarization of a suspension of ellipsoidal particles covered with two confocal shells.

Differences in the electrical parameters of the membrane between normal and homozygous β-thalassemic cells have been evidentiated.
Field Desorption and Fast Atom Bombardment Mass Spectrometry of Spirostanol and Furostanol Saponins from Paris polyphylla
Authors: Schulten H.-R. , Singh S. B. , Thakur R. S.
Published: August 2018

The application of field desorption and fast atom bombardm ent mass spectrometry for molecular weight determination and structural elucidation of spirostanol and furostanol saponins isolated from Paris Polyphylla Sm. (Liliaceae) is reported. The capacity and limitations of these methods for sugar sequencing, differentiation of isomers and purity control of oligoglycosidic natural products are discussed
Miotoxin-A: A Novel Macrocyclic Trichothecene from the Brazilian Plant Baccharis coridifolia / Miotoxin-A, Trichothecene, Compositae. Poisonous Plants, NMR -and X -Ray Structure Analysis
Authors: Habermehl Gerhard G. , Stegemann Jürgen
Published: August 2018

The isolation of Miotoxin-A*, a novel macrocyclic trichothecene from Baccharis coridifolia DC. (Compositae) is described. The structure has been determined to be 4-hydroxy-roridin E by means of NMR-spectroscopy and X-ray structure analysis
Catabolism of (R)-Amygdalin and (R)-Vicianin by Partially Purified ß-Glycosidases from Prunus serotina Ehrh. and Davallia trichomanoides
Authors: Kuroki Gary , Lizotte Pauline A. , Poulton Jonathan E.
Published: August 2018

Mature black cherry (Prunus serotina Ehrh.) seeds accum ulate high levels of the cyanogenic disaccharide (R)-amygdalin. Extracts from these seeds contain two β-glycosidases which have been identified and completely resolved by DEAE-cellulose ion-exchange chromatography. Amygdalin hydrolase hydrolyzed (R)-am ygdalin at an optimum pH of 5.5, releasing (R)-prunasin and D-glucose. This enzyme showed highest activity towards (R)-am ygdalin and failed to hydrolyze (R)-prunasin. linamarin, β-gentiobiose and cellobiose. A distinct β-glycosidase, prunasin hydrolase, displayed a pronounced preference for (R)-prunasin, hydrolyzing this cyanogenic monosaccharide at an optimum pH of 6.5 to mandelonitrile and D-glucose. Prunasin hydrolase was inactive towards (R)-am ygdalin, linamarin, and β-gentiobiose. Both enzymes showed significant activity towards the artificial substrates β-ONPGlu and β-PNPGlu but did not hydrolyze α-PNPGlu. In view of the pronounced specificity of these enzymes towards endogenous cyanogens, it is concluded that upon disruption of black cherry seeds (R)- amygdalin is catabolized to mandelonitrile in a stepwise manner (the sequential mechanism) by amygdalin hydrolase and prunasin hydrolase with (R)-prunasin serving as intermediate.

Young fronds of Davallia trichomanoides are rich sources of (R)-vicianin (the β-vicianoside of (R)-mandelonitrile). A β-glycosidase, vicianin hydrolase, has been partially purified from frond extracts by ion-exchange chromatography. At the optimum pH of 6.0, this enzyme showed highest hydrolytic activity with (R)-vicianin, although both (R)-am ygdalin and (R)-prunasin could be hydrolyzed at approximately 15% of the rate observed with (R)-vicianin. It failed to hydrolyze β-gentiobiose, cellobiose, linamarin and α-PNPGlu. Closer exam ination revealed that (R)-vicianin and (R)-amygdalin were hydrolyzed at the aglycone-disaccharide bond (the simultaneous mechanism) yielding mandelonitrile and the respective disaccharides vicianose and β-gentiobiose
About the Similarity between Polymaleic Acid and Water Soluble Humic Fractions
Authors: Martin F. , Gonzalez-Vila F. J. , Lüdemann H.-D.
Published: August 2018

The content of aromatic units in polymaleic acid (PMA) prepared by standard procedures is determined by C -13 NMR and three different oxydation procedures. It is shown that all destructive oxydation procedures lead to an aromatic carbon content that is significantly higher than the aromaticity content expected from the m ethod of preparation and derived from the C-13 NMR spectra.

It is concluded, that benzenecarboxylic acids are formed in the process of oxydation of PMA. The yield increases with the oxydative strength of the m ethod applied
Isolation and Characterization of Tributyltin Resistant Mutants of Escherichia coli
Authors: Singh Akhand P. , Singh Kiran
Published: August 2018

Two classes of tributyltin (TBT) resistant, spontaneous mutants of Escherichia coli K-12 were isolated, using a cytochrome containing (W 1485) and a cytochrome deficient (SASX76) strain. In contrast to the cytochrome sufficient strain, the cytochrome deficient strain was found to be fifty times more sensitive to TBT. The class I mutants, isolated from strain W 1485, also showed crossresistance to triphenyltin (TPT). As compared to its wild type parent, the TBT-resistant mutants exhibited mucoid colony type, aberrant cell morphology and reduced uptake of TPT. Based on these results, it was suggested that the resistance of class I mutants to TBT may be associated with above mentioned alterations. The class II TBT-resistant mutants were isolated from the cytochrome deficient strain, SASX76. In comparison to class I mutants, these class II mutants were found to have TBT-resistant membrane bound adenosine triphosphatase (ATPase) which may account for their resistance to TBT
Chemosystematics of Japanese Heterotropa (Aristolochiaceae)
Authors: Hayashi Nanao , Maeshima Kazuyuki , Murakami Tadayuki , Komae Hisashi
Published: August 2018

A survey of chemical composition of forty-four species of Heterotropa growing in Japan and Formosa showed that four chemical groups could be distinguished and that two routes of distribution to Japan from China may be suspected on the basis of phenylpropane components.
Two Dimensional Double-Quantum and COSY Spectra of Porcine Adenylate Kinase
Authors: Rösch Paul , Gross Karl-Heinz
Published: August 2018

1H double-quantum and COSY NMR-spectra of the porcine protein adenylate kinase have been obtained in order to assign aromatic spin systems within this protein, which contains seven tyrosyl, five phenylalanyl, and two histidyl residues. Double-quantum spectroscopy in its simple form allowed the assignment of five connectivities in the aromatic region and therefore proved inferior to COSY, which allowed the assignment of connectivities within nine aromatic residues.
Polycation-Cell Surface Interactions and Plasma Membrane Compartments in Mammals. Interference of Oligocation with Polycationic Condensation
Authors: Antohi Stefan , Brumfeld Vlad
Published: August 2018

At lower concentrations, polyarginine, polylysine, protamine, histones H 1, H2A, H2B and H3 cause lysis of human erythrocytes, whereas at higher concentrations inner histones are not hemolytic but induce only surface condensation and alterations in the cell-shape. Antibody coated erythrocytes treated with polyarginine result in ghost-like spheres having globular bodies 1 μm in diameter on the surface. Human fibroblasts and lymphocytes, and Ehrlich ascites cells treated with polyarginine also form surface globular bodies similar in size. Nucleate cell-poly-arginine mixtures with lower polycation doses result in cytolysis, while higher polycation doses produce pyknosis of the cell surface accompanied by reorganization of a membrane-like structure. Changes in spectrofluorometric values result from 1,6 -diphenyl-1,3,5-hexatrien binding to cell lipids, match the plasma membrane alterations. Reciprocal shake incubation am plifies and/or conditions these polycation-induced alterations. The homogeneity of pyknotic surface bodies and the apparent polycationic membrane reorganization requiring oscillatory friction forces suggest the preexistence of a multizonal glycocalyx distribution corresponding to plasma membrane compartments. The possible role of this compartmentalization in receptor and membrane recycling, as well as the involvement of reversible catalytic-like polycation condensation in macromolecular changes are discussed.
Electron Microscopic Study of the Polymyxin Treated Goat Erythrocytes
Authors: Mandal T. K. , Chatterjee S. N.
Published: August 2018

Polymyxin B produced dose dependent changes in the surface topography of the goat erythrocyte cells. Transformation from the normal biconcave discs through crenated structures to the final rounded or spherical shape was recorded by scanning electron microscopy. A maxim um of three to four crenations per cell was recorded corresponding to a polymyxin dose of 15.62 ng/ml. Transmission electron microscopy of the ultrathin sections of treated or untreated erythrocytes indicated that the crenations were formed by protrusions of the plasma membrane, occurring presumably because of the local increase of membrane fluidity after polymyxin treatment. Changes in the shape of the erythrocytes to the ultimate rounded forms were also indicated by the transmission electron microscopy.
Statistical Analysis of Quantum Bump Parameters in Limulus Ventral Photoreceptors
Authors: Keiper Winfried , Schnakenberg Jürgen
Published: August 2018

A statistical analysis of current quantum responses (“bumps”) to the absorption of single photons in the ventral photoreceptor of Limulus is presented. The analysis is performed in terms of bump parameters among which two groups are distinguished: “time-like parameters” with distributions independent of individual cells and “current parameters” the distribution of which differ for different cells. The analysis yields a set of “primary” parameters with mutually uncorrelated fluctuations. The results are interpreted by a new model formulation on the basis of a transmitter hypothesis for the transduction. The model separates latency from amplification and postulates the existence of different sources of fluctuations among which one includes individual cell properties.
Multiple Periodicities in the Circadian System of Unicellular Algae
Authors: Hoffmans-Hohn Margarete , Martin Wolfgang , Brinkmann Klaus
Published: August 2018

Three periodicities in the circadian range are observed when measuring circadian parameters of unicellular organisms in long running experiments (more than 15 days). This is demonstrated for different organisms (Chlamydomonas, Euglena, Chlorella) and different parameters (auto­ kinesis, extracellular pH, CO2- and O2-partial pressure). Having excluded analytical and experimental artefacts (i.e. filter leakage and subpopulation effects), the multiple periodicities have to be interpreted in a physiological model. The three periodicities always exhibit two common features: The locations of the side peaks are symmetrical to the middle peak and their energy contribution is always the same. We therefore favour the model of multiplicative coupling between the circadian oscillator and a low frequency oscillator modulating the amplitude of the circadian rhythm. Since the low frequency rhythm is not correlated to any exogenously running periodicity of the experimental surroundings, it is considered as generated by an endogenous oscillator. This shows the existence of different biological long time oscillators in one single cell and contradicts the so-called master-clock hypothesis stating that one cell has only one clock related oscillator.
Notizen: Analysis of a Sex-Attractant System in the Noctuid Moth Rhyacia baja Schiff
Authors: Priesner Emst
Published: August 2018

Binary combinations of (Z)-7-dodecenyl acetate and (Z)-9-tetradecenyl acetate in a 1/10 ratio were highly attractive to Rh. baja males in field trapping tests conducted in southern Germany. Trap captures increased further on adding 0.1 or 0.3% of (Z)-5-dodecenyl acetate to this lure; higher amounts of this chemical were strongly inhibitory, as were additions of > 3% of (Z)-11-hexa-decenyl acetate. The trapping data are considered in terms of electrophysiological responses of five types of antennal receptor cells.
Metabolie Activity of Hydroxycinnamic Acid Glucose Esters in Cell Suspension Cultures of Chenopodium rubrum
Authors: Strack Dieter , Bokern Maria
Published: August 2018

Cell suspension cultures of Chenopodium rubrum accumulate high amounts of metabolically active glucose esters of p-coumaric and ferulic acid. Pulse-labelling experiments using [14C]phenylalanine and application of the phenylalanine ammonia-lyase (PAL) inhibitor L-α-aminooxy-β-pnenylpropionic acid (AOPP) revealed that the glucose esters are subject to high turnover. A considerable portion of the ferulic acid was found as an insoluble component, probably bound to cell wall material. Application of m-fluoro-DL-tyrosine (MFT), an effective inhibitor of tyrosine biosynthesis via L-arogenate, markedly increased the amount of 1-p-coumaroyl-and 1-feruloyl-glucose accumulated.
Functional and Regulatory Properties of H+ Pumps at the Tonoplast and Plasma Membranes of Zea mays Coleoptiles
Authors: Hager A. , Biber W.
Published: August 2018

A microsomal membrane fraction (6000 x g supernatant of a cell homogenate), isolated from coleoptiles of Zea mays, was separated by isopycnic sucrose density gradient centrifugation in the presence of EDTA and without a prior pelleting step to avoid irreversible sticking of different membrane species. The membrane fractions were characterized by assaying commonly used marker enzymes, and the levels of activity investigated of ATP hydrolysis, ATP-dependent H+ transport, and co- and countertransport of ions, such as Cl- , fumarate2-, K+ and Li+. The following results were obtained:

(1) ATP hydrolysis is performed by different enzymes associated with different membranes:

- vacuolar acid phosphatase (AP; inhibited by molybdate);

- Golgi phosphatase, revealing IDPase, pNPase and ATPase activity (not inhibited by molybdate);

- ATPase activity of residual submitochondrial particles (sensitive to azide);

- a H+-translocating ATPase at tonoplast membranes (Km(ATP) = 0.29 mᴍ; pH 7.5; stimulated by uncouplers and completely inhibited by NO-
3);

- the H+-translocating ATPase of the plasmalemma (Km(ATP) = 0.39 mᴍ at pH 6.5, inhibited by vanadate, but not by NO-
3). The latter activity is evident only after an osmotic shock, indicating that PL vesicles primarily exist as inside-in-vesicles.

(2) ATP-fueled H+ pumps are localized at tonoplast (TO) and plasmalemma (PL) vesicles, they differ to some extent in their properties:

(a) The PLH+ pump has a very narrow pH optimum and exhibits highest levels of activity at pH 6.5 with a pronounced increase of activity between pH 7.5 and 6.5 (properties, obviously important in vivo for the regulation of active H+-extrusion by certain growth substances, which affect the cytoplasmic pH (Hager and Moser, Planta 1984, in press); in contrast, TO H+ pumps show a considerably wider pH optimum with highest levels of activity around pH 7.5.

(b) In variance to the PL H+ pump the activity of TO pumps (Km(ATP) = 0.24 mᴍ) is regulated via the oxidation state of essential thiol groups. Their oxidation to the S -S - form (e.g. by blue light in the presence of a flavin) causes an inactivation, whereas a re-reduction by GSH or cystein restores the activity [51].

(c) The ATP-fueled H+ transport into TO vesicles depends on an anion co-transport; most effective is Cl- , but there is also a stimulation by organic ions, C4 and C5 dicarboxylates, such as malate, succinate, fumarate, 2-oxoglutarate and aspartate; NO-
3 is inhibitory.

(d) H+-transport into sealed PL vesicles is also anion dependent. In this case, however, NO-
3 is as effective as Cl-.

(3) The TO membranes contain a H+/K+ exchange mechanism responsible for a secondary active K+ uptake into the vacuole. This mechanism could be the reason for a lower (ATP dependent) acidification of TO vesicles in the presence of K+ compared with Li+. - Similar effects are observed with plasmamembrane vesicles, but in this case there is still the question whether a H+/K+-exchange, a K+ channel, or both are acting.
Octopamine Modulates the Sensitivity of Limulus Ventral Photoreceptor
Authors: Stieve H. , André E.
Published: August 2018

The effect of extracellularly applied octopamine (10-5mol/l) on the receptor potential of the Limulus ventral photoreceptor was studied. Octopamine increases the sensitivity of the photoreceptor in the light-adapted state more than in the dark-adapted state. Extracellular application of phentolamine (10-5mol/l) has an opposite, antagonizing effect. The octopamine effect, though reproducible in the individual experiment, varies greatly from preparation to preparation.
Dose Rate Dependence of Radiation Induced IgG Membrane Receptor Alteration [1]
Authors: Ojeda F. , Moraga D. , Guarda M. I. , Folch H.
Published: August 2018

Mouse lymph node lymphocytes are irradiated at differ­ent dose rates and the B-cell receptors to anti IgG are tested. The expression of receptors is inhibited by irradia­tion. It is shown that the effectivity of irradiation increases with decreasing dose rate suggesting that membrane dam ­ age may be important for situations of chronic irradiation or implant radiotherapy.
Isomeric Di-C-glycosylflavones in Fig (Ficus carica L.)
Authors: Siewek Fred , Herrmann Karl , Grotjahn Lutz , Wray Victor
Published: August 2018

Two isomeric C-glycosides of apigenin (apigenin-6-C-glucosyl-8-C-arabinoside (schaftoside), apigenin-6-C-arabinosyl-8-C-glucoside (isoschaftoside)) were isolated from leaves of Ficus carica with preparative HPLC.

1The glycosides were identified by UV-, 1H-NMR-, 13C-NMR-spectroscopy and FAB-MS.

Their concentration in fruits and leaves were determined by gradient HPLC on reversed phase material.
The Scent Substances of Pierid Butterflies (Hebomoia glaucippe Linnaeus) and the Volatile Components of Their Food Plants (Crataeva religiosa Forst.)
Authors: Hayashi Nanao , Nishi Akihiko , Murakami Tadayuki , Maeshima Kazuyuki , Komae Hisashi , Sakao Takashi
Published: August 2018

The scent secretions of two subspecies of Hebomoia glaucippe, which are pierid butterflies, and the essential oils of their food plant were investigated by means of GC and GC-MS. The scent substances of either subspecies are found to be only E-β-ocimene, and the volatile components of Crataeva religiosa were identified as 2-hexanal, 3-hexen-1-ol, p-cymene, limonene, linalool, α-ionone, and β-ionone. Electroantennogram (EAG) were recorded with the antennae of adult male and female butterflies. It was found that EAG responses of male to E-β-ocimene were greater than those of females.
Inhibition of Photosystem II by UV-B-Radiation
Authors: Tevini M. , Pfister K.
Published: August 2018

The effect of UV-B-radiation on PSII activity of spinach chloroplasts was analyzed by measuring the integrity of the herbicide-binding protein (HBP 32), by measurement of fluorescence induction in the presence of Diuron (DCMU), and by mathematical analysis of the fluorescence induction curves. It was shown that UV-B inactivates the PSII α-centers but not PSII β-centers. However, the possibility cannot be excluded that in addition the donor site of PSII near the reaction center is attacked by UV-B-radiation.
Isolation of Populations of Antipeptide Antibodies Directed against Different Epitopes of the Same Fragment
Authors: Chersi Alberto , Greger Christiane , Houghten Richard A.
Published: August 2018

Rabbit antibodies against small peptides may be composed by subpopulations recognizing different epitopes made likely by few aminoacids. This explains the frequent crossreactivity of antipeptide antibodies with unrelated peptides.

A suitable use of immunoadsorbents is suggested to obtain truly specific antibodies able to react with restricted amino acid sequences.
Veränderung des Tocochromanolmusters einiger Pflanzenöle (Sojabohne, Lupine, Sonnenblume und Weizen) während Keimung und Wachstum / Alteration of Tocochromanol Pattern in Some Plant Oils (Soybean. Lupine. Sunflower and Wheat) during Germination and Growth
Authors: Schulz Hartwig , Lausch Gabriele , Feldheim Walter
Published: August 2018

Seed, sprout and plant oils from soybean (Soja hispida), lupine (Lupinus mutabilis), sunflower (Helianthus annuus) and wheat (Triticum aestivum) were assayed for their tocochromanol content and composition. High-performance liquid chromatography (HPLC) with fluorescence detection was used to determine tocopherols and tocotrienols of laboratory-extracted oils. In general, leaves of lupine, soja, and wheat with a high chlorophyll-a-content also were found to be rich of alpha-tocopherol; roots contained very little or no tocopherol. Contents of gamma-and delta-tocopherol in soja and lupine decreased during germination and growth, whereas the alpha-tocopherol concentration increases significantly. This evidence suggests that non-alpha-to-copherols might be methylated enzymatically to alpha-tocopherol. Tocochromanol pattern of wheat also changes characteristically in an analogous manner during plant development. Germ i­ nation of sunflower seeds also resulted in a conversion of beta-and gamma-tocopherols and in a slight decrease of the predominantly occurring alpha-tocopherol. In relation to the lipid content, the concentration of total tocopherols in oil plants increases significantly during growth. Possible implications for the biosynthesis of tocochromanols are discussed.
Quinolizidine Alkaloids as Nitrogen Source for Lupin Seedlings and Cell Cultures
Authors: Wink M. , Witte L.
Published: August 2018

The alkaloid patterns during germination and seedling development of Lupinus polyphyllus, L. angustifolius, L. albus, L. pubescens, Cytisus scoparius, Baptisia australis, Spartium junceum and Laburnum anagyroides were studied by capillary glc and EI-MS and CI-MS. The alkaloid contents were relatively high in the seeds and decreased by 20-100% during germination and the early developmental stages. The plants with fully developed leaves were able to synthesize new alkaloids. The decrease of alkaloid concentrations during germination was interpreted in terms of alkaloid turnover and use of the alkaloidal nitrogen for seedling development. The ability of plants to rely on the alkaloidal nitrogen as a nitrogen source could also be shown in lupin cell cultures which could survive and even grow on media which contained sparteine as the sole nitrogen source.
Die Kristallstruktur des Ectoin, einer neuen osmoregulatorisch wirksamen Aminosäure / The Crystal Structure of Ectoine, a Novel Amino Acid of Potential Osmoregulatory Function
Authors: Schuh Willi , Puff Heinrich , Galinski Erwin A. , Trüper Hans G.
Published: August 2018

The crystal structure of ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid) isolated from the extremely halophilic phototrophic bacterium Ectothiorhodospira halochloris was determined by X-ray analysis. This novel cyclic amino acid forms zwitterionic molecules with delocalized π-bonding in the N-C-N group of the hydrated pyrimidine ring. The molecules are connected by N-H ...O hydrogen bonds. The excellent solubility of ectoine in water can be explained by its structural features which also account for its function as a compatible solute in halophilic bacteria.
A Disappearance of a 24-kDa Acid-Soluble Protein from Liver Chromatin of Normal and Starved Hens Following ᴅ-Galactosamine Administration
Authors: Pałyga Jan
Published: August 2018

Normal and starved adult chickens were injected intraperitoneally with ᴅ-galactosamine hydro­ chloride (0.5 g/kg body weight) and 6 h later liver chromatin acid-soluble proteins were isolated. These proteins were resolved by a two-dimensional polyacrylamide gel electrophoresis in the presence of non-ionic detergent, Triton X-100, in the first dimension and anionic detergent, sodium dodecyl sulfate, in the second dimension. Although spotting patterns of acid-soluble chromatin proteins were remarkably similar between normal and starved control birds and those receiving ᴅ-galactosamine, a disappearance of a 24-kDa protein after administration of this agent was found. Moreover, it was shown that this protein was also completely absent in the chicken erythrocyte chromatin which was known to be inactive in RNA synthesis.

It seems that the disappearance of the 24-kDa chromatin protein may be associated with inhibiting of transcription in hen liver after ᴅ-galactosamine administration and during hen erythrocyte maturation.
Binary Oscillation of Delayed Luminescence: Evidence of the Participation of QB
- in the Charge Recombination
Authors: Hideg Éva , Demeter Sándor
Published: August 2018

The flash-induced oscillation of a slowly decaying component of delayed luminescence (half time ~ 42 s) was investigated in spinach chloroplasts for various redox states of the secondary acceptor pool (QB). In preilluminated chloroplasts (30 s light followed by 5 min dark) the slow component exhibited a period-4 oscillation as a function of flash number. Upon oxidation of a major part of the QB pool by dark-adaptation or by ferricyanide treatment of chloroplasts, the period-4 oscillation was converted into a period-2 oscillation, providing direct experimental evi­ dence of the participation of QB
- in the charge recombination reaction. The measured oscillatory patterns could be simulated in model calculations by assuming that the slow component originates from charge recombination of the redox couples S2QB
- and S3QB
-.
Chemical Composition of the Wing Gland and Abdominal Hair Pencil Secretions of the Male African Sugarcane Borer, Eldana saccharina (Lepidoptera: Pyralidae)
Authors: Burger B. V. , Mackenroth W. M. , Smith Denice , Spies H. S. C. , Atkinson P. R.
Published: August 2018

In addition to the previously identified wing gland lactone, eldanolide, and the tail brush components, vanillin and p-hydroxybenzaldehyde, several further terpenoid compounds, saturated and unsaturated alcohols and acids, a thioalcohol, as well as two saturated macrocyclic lactones, were identified in the wing gland and tail brush secretions of the male African sugarcane borer Eldana saccharina (Walker).
MTD Approach to Quantitative Structure-Activity Relationships for Cardiotonic Steroids
Authors: Bohl Martin , Simon Zeno
Published: August 2018

A minimal topological difference (MTD) approach is made to describe quantitative structure-activity relationships (OSAR) for the Na+, K+-ATPase inhibitory activity of cardiotonic steroids. The calculations take into account 20 derivatives of digitoxigenin, digoxigenin, and gitoxigenin with small substituents at different sites of the steroid backbone. A multiple correlation coefficient of r = 0.916 is obtained using the MTD and an indicator variable for the presence of a 15β substituent. The corresponding receptor map reveals receptor wall vertices in the C11 , C12, C15, and C22 regions. Both 3β and 16β substituents are found to contain receptor cavity vertices. The MTD results are discussed with respect to lactone-ring conformational investigations presented and they are compared with findings of previous structure-activity studies.
Reaction of Fluorescein Isothiocyanate with Thiol and Amino Groups of Sarcoplasmic ATPase
Authors: Swoboda Gertrude , Hasselbach Wilhelm
Published: August 2018

Several model compounds containing thiol and/or amino groups (mercaptoethanol, glutathione, cysteine, ethanolamine, glycine) were studied with respect to their reactivity towards fluorescein isothiocyanate (followed spectrophotometrically at 504 and 412 nm), stability of product and long­ wave absorption maximum of the fluorescein residue attached. Thiol groups reacted by far more readily than amino groups. A specific effect was observed with cysteine, indicating an intramolecular transfer of the fluorescein residue from SH to NH2.

With sarcoplasmic vesicles both types of reactions were observed. The ratio of products, which can be distinguished by their different stabilities and absorption spectra, depended on the absence or presence of detergents. While with native vesicles the NH2 reaction predominated, with vesicles solubilized with sodium dodecylsulfate, octaethyleneglycol mono-n-dodecyl ether or 1-0-tetradecyl-propanediol-(1,3)-3-phosphorylcholine the SH reaction became prevailing. Already 0.35 mg sodium dodecylsulfate per mg protein were sufficient to give rise to dithiourethane formation exclusively. Excess fluorescein isothiocyanate reacted with several thiol groups of dodecylsulfate-solubilized vesicles. In the presence of ATP binding of fluorescein isothiocyanate to native vesicles was significantly reduced.

Total blockage of the vesicular SH groups with N-ethyl-maleimide led to preparations that reacted with fluorescein isothiocyanate much more slowly, compared to native vesicles. Octaethy­ leneglycol mono-n-dodecyl ether or 1-0-tetradecyl-propanediol-(1,3)-3-phosphorylcholine in the assay accelerated the thioureide formation from N-ethylmaleimide modified vesicles, whereas sodium dodecylsulfate prevented it almost completely.

Our results support the suggestion that one or several thiol groups in vicinity of the highly reactive lysyl residue might play a role in the fast specific reaction, which is only observed with intact native vesicles.
Linear Dichroism Spectroscopy of Retinal with Picosecond Time Resolution
Authors: Lippitsch M. E. , Riegler M. , Aussenegg F. R. , Friedman N. , Sheves M. , Mazur Y. , Margulies L.
Published: August 2018

For the first time linear dichroism spectroscopy has been extended to the picosecond time regime. 11-cis retinal, all-trans retinal and 1,8-diphenyl-1,3,5,7-octatetraene (DPOT) are incorporated into polyethylene films and oriented by stretching the films. By measuring picosecond transient absorption spectra polarized parallel and perpendicular to the stretching direction and calculating the dichroic ratio we get informations about the molecular geometry in excited singlet and triplet states. The results may have relevance to vision.
On the Specificity of the Herbicide Chlorsulfuron in Intact Spinach Chloroplasts
Authors: Homeyer Uwe , Schulze-Siebert D. , Schultz G.
Published: August 2018

In vitro incubation of intact spinach chloroplasts with 1 mᴍ Pyruvate was used to study the specificity of action of the herbicide Chlorsulfuron on the synthesis of valine, alanine and fatty acids. As a result, increasing concentrations of the herbicide strongly inhibited valine synthesis while fatty acid synthesis via pyruvate dehydrogenase complex (PDC) and alanine formation by transamination reaction was promoted.
High Yields of DNA-Transfer into Mouse L-Cells by Electropermeabilization
Authors: Stopper H. , Zimmermann U. , Wecker E.
Published: August 2018

DNA transfection in mouse L-cells was performed by means of the electropermeabilization technique (U. Zimmermann, G. Pilwat, and F. Riemann, Z. Naturforsch. 29, 304 (1974)). The plasmid pSV 2-neo used leads to neomycin-resistance in stably transfected L-cells. Optimized conditions resulted in high yields of clones at relatively low DNA concentration. The influence of temperature during pulse application and during the subsequent resealing process as well as the field parameters and medium com­position are discussed.
Female Urinary Chemosignals Influence Scent-Marking Behavior in Male Mongolian Gerbils (Meriones unguiculatus)
Authors: Probst Bodo
Published: August 2018

The influence of females on the amount of scent-marking behavior displayed by male Mongolian gerbils was investigated. Males isolated from females scent mark at a low level which increases more than two-fold if females are present in the room for three weeks without direct contact with the males. A similar increase is obtained by application of pooled female urine directly onto the males’ noses.
Do Cyanobacteria Contain a Membrane Bound Cysteine Oxidase?
Authors: Barsky Eugene L. , Kamilova Faina D. , Samuilov Vitaly D.
Published: August 2018

The oxidation of cysteine with 02 is facilitated by isolated membranes of the cyanobacteria Anacystis nidulans and Anabaena variabilis, and further stimulated by Fe3+. This reaction accelerates with increasing the pH value and is suppressed by cyanide, benzylhydroxamate, hydroxylamine, but not azide. The agents mentioned inhibited the respiration of the membranes with ascorbate and N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) effectively, but did not influence their nonenzymic oxidation. It is inferred that ascorbate in combination with TMPD is oxidized via membrane oxidases. Cysteine oxidation apparently proceeds non-enzymatically and is catalyzed by the cations of heavy metals.
On the Chemical Reactivity of the Phytochrome Chromophore in the Pr and Pfr Form
Authors: Thümmler Fritz , Eilfeld Peter , Rüdiger Wolfhart , Moon Doo-Khil , Song Pill-Soon
Published: August 2018

The reactivity of the phytochrome chromophore and related tetrapyrroles towards ozone and tetranitromethane was investigated. Both oxidizing reagents cause bleaching of the main absorp­tion band of the pigment. The rate constants for this bleaching were determined under conditions of pseudo first order reaction kinetics. The rate constants for the reaction with ozone are similar for native phytochrome and for freely accessible tetrapyrroles (biliverdin, small chromopeptides from phytochrome) indicating that accessibility is not the limiting factor for the reaction with ozone. Under a variety of conditions, the Pfr chromophore reacts by about 10% faster than the Pr chromophore. This may reflect the true difference in reactivity. The rate constants for the reaction with tetranitromethane are much larger for biliverdin, bilirubin and small chromopeptides from phytochrome than for native phytochrome. The limiting factor for this reaction in native phytochrome therefore is the accessibility of the chromophore by the reagent. Previous conclusions on the difference in exposure of the tetrapyrrole chromophore in Pr and Pfr are confirmed.
Rate and Rate-Determining Step of Hydrogen-Atom-Induced Strand Breakage in Poly(U) in Aqueous Solution under Anoxic Conditions
Authors: Bothe E. , Selbach H.
Published: August 2018

The rate constant for strand breakage in poly(U) after reaction with hydrogen atoms in deoxygenated aqueous solution has been determined to be k = 1.5 s-1 at pH = 4-5 and 24 °C. Dithiothreitol has been found to prevent strand break formation by reacting with H-adduct radicals of poly(U) with a rate constant of 5 × 106 M-1 s-1. It is concluded that the rate-deter­mining step in H atom-induced strand breakage in poly(U) at pH ≦ 6 is the decay of uracil moiety H-adduct radicals via H-abstraction from the ribose moiety.
Sex Pheromone Components in the New Zealand Greenheaded Leafroller. Planotortrix excessana (Lepidoptera: Tortricidae)
Authors: Galbreath R. A. , Benn M. H. , Young H. , Holt V. A.
Published: August 2018

Planotortrix excessana was found to include moths of two distinct pheromone-types which were not mutually attractive. Tetradecyl acetate and (Z)-8-tetradecenyl acetate were identified as pheromone components in one, and two other tetradecenyl acetates, probably (Z)-5-and (Z)-7-tetradecenyl acetate, in the other. By contrast with other pheromones reported from the tribe Archipini,⊿11-tetradecenyl compounds were not found in either pheromone-type.
Calcium/Sodium Binding Competition in the Gating of Light-Activated Membrane Conductance Studied by Voltage Clamp Technique in Limulus Ventral Nerve Photoreceptor
Authors: Stieve H. , Pflaum M. , Klomfaß J. , Gaube H.
Published: August 2018

The membrane current vs. voltage dependence was measured in Limulus ventral nerve photo­receptors at various external Ca2+ and Na+ concentrations, using the voltage clamp technique. Lowering the external concentration of the divalent cations Ca2+ and Mg+ to < 1 μmol/l by adding EDTA causes

1)the light-induced transient conductance increase to disappear and

2)the reversal potential of the membrane current in the dark to shift to a positive value between + 10 and + 20 mV. This value is about the same as the (VrevJD), reversal potential of the total light current under normal ionic conditions. If the external Na+ is lowered to 50 mmol/1 (i.e. 10% of the normal concentration) simultaneously with the lowering of the divalent cation concentration described above, the light response is not abolished and VrevJD is shifted less. The extent of this antagonism depends on the sodium sub­stitute; it is stronger if choline is used instead of lithium.

Lowering of sodium alone to 50 mmol/1, in a saline containing normal Ca2+ and Mg2+ concen­trations, does not change the membrane dark current vs. voltage curve and so VrevJD is not altered; Vrev⊿JL, the reversal potential of the light-induced current, however, is reduced by 10 mV (from +20 to +10 mV). This reduction in Vrev⊿JL can be accounted for by the reduction of the sodium gradient across the cell membrane.

Raising the external Ca2+ concentration to 40 or 100 mmol/l has no conspicuous effect on the membrane current vs. voltage dependence and the gating of the light-induced conductance in­crease.

The results are consistent with our working hypothesis that the gating of the light-activated ion channels in Limulus photoreceptor is controlled by negative binding sites for which calcium- and sodium ions compete with antagonistic actions.
Isolation of the Phytoalexin Medicarpin from Leaflets of Arachis hypogaea and Related Species of the Tribe Aeschynomeneae
Authors: Strange R. N. , Ingham J. L. , Cole D. L. , Cavill M. E. , Edwards C. , Cooksey C. J. , Garrattd P. J.
Published: August 2018

A phytoalexin produced by the leaflets of seven cultivars of Arachis hypogaea (groundnut) after natural infection by Cercospora arachidicola or Phoma arachidicola has been characterised as the isoflavonoid (+)-medicarpin (3-hydroxy-9-methoxypterocarpan). Treatment of excised ground­nut leaflets with an aqueous solution of CuSO4 or with a spore suspension of the fungus Helmin-thosporium carbonum has also been found to stimulate medicarpin biosynthesis.
Proton Uptake by Light Induced Interaction between Rhodopsin and G-Protein
Authors: Schleicher Andreas , Hofmann Klaus Peter
Published: August 2018

The light-induced proton uptake of rod outer segment disc membranes has been investigated in the absence and presence of G-protein. Proton uptake was measured as the alkalisation of the suspending medium using a pH electrode and/or the indicator dye bromocresol purple. It was found that besides the known proton uptake of photolysed rhodopsin additional uptake of one proton accompanies formation of the complex between rhodopsin and G-protein. No measurable proton uptake was found under conditions of rapid redissociation of the complex indicating an only transient protonation during its lifetime. Proton uptake was the same in washed membra­nes recombined with G-protein and in ordinarily stacked rod outer segments. The additional proton uptake reported here is not due to enhanced metarhodopsin II.