bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on Synergism between Glucose and Amino Acids with Respect to Insulin Release in vitro
Authors: Khalid Qamar , Rahman M. Ataur
Published: August 2018

The mutual enhancement of the effect of insulin release by glucose and amino acids is not clearly understood. Present in vitro studies with isolated rat islets were undertaken to elaborate the role of amino acids on insulin release, particularly their interaction with glucose as well as among each other, which has been reported to lead to synergism in the hum an subjects.

In the presence of 8.3 mм glucose, both arginine, as well as, leucine potentiated the effect of glucose which increased progressively with the increasing concentrations of the amino acid. This effect of arginine was not synergistic in nature because arginine did not stimulate insulin release in the absence of glucose.

The effect of glucose and leucine was found to be additive and not synergistic.

No synergism was exhibited by any of the amino acid pairs tested in the present study. Thus both phenylalanine and lysine did not potentiate the effect of either arginine or leucine. Arginine showed a mild, but significant potentiating effect on leucine-stimulated insulin release.

It is suggested that synergism between glucose and amino acids and between certain amino acid pairs reported in m an may not be due to the direct effects of these stimuli on the beta cells, but some other factors in vivo may be involved.
Der Einfluß des pH, der Temperatur und der Polarität des Lösungsmittels auf die Absorption des reduzierten und oxidierten Nicotinamidadenin-dinucleotids bei 260 nm / Influence of pH, Temperature and Polarity of the Solvent on the Absorption of NADH+ and NADH at 260 nm
Authors: Schauenstein Erwin , Saenger Wolfram , Schaur Rudolf Jörg , Desoye Gemot , Schreibmayer Wolfgang
Published: August 2018

Assuming a reversible equilibrium of an unfolded and a base-stacked conformation of both NADH and NAD+ the influence of pH, temperature and methanol on this equilibrium was studied as indicated by the UV-absorption of the adenine band at 260 nm. By the addition of methanol as well as by an increase of temperature the equilibrium is shifted to the unfolded conformation. An increase of the H+ concentration seems to favor the unfolded conformation in the case of NAD+ while for NADH a decrease of the absorption coefficient is pointing to a higher percentage of the stacked conformation at lower pH.

From the temperature variation of the absorption coefficients the enthalpies for the conformational change were calculated and compared with data obtained by different methods.
Degradation of (–)-Ephedrine by Pseudomonas putida Detection of (–)-Ephedrine: NAD+-oxidoreductase from Arthrobacter globiformis
Authors: Klamann E. , Lingens F.
Published: August 2018

A bacterium utilizing the alkaloid (-)-ephedrine as its sole source of carbon was isolated by an enrichment-culture technique from soil supplemented with 4-benzoyl-1,3-oxazolidinon-(2). The bacterium was identified as Pseudomonasputida by morphological and physiological studies. The following metabolites were isolated from the culture fluid: methylamine, formaldehyde, methyl- benzoylcarbinol (2-hydroxy-1-oxo-1-phenylpropane), benzoid acid, pyrocatechol and cis, cis- muconic acid. A pathway for the degradation of (-)-ephedrine by Pseudomonas putida is proposed and compared with the degradative pathway in Arthrobacter globiformis.

The enzyme, which is responsible for the first step in the catabolism of (-)-ephedrine could be demonstrated in extracts from Arthrobacter globiformis. This enzyme catalyses the dehydrogena- tion of (-)-ephedrine yielding phenylacetylcarbinol/methylbenzoylcarbinol and methylamine. It requires NAD+ as cofactor and exhibits optimal activity at pH 11 in 0.1 m glycine/NaOH buffer. The Km value for (-)-ephedrine is 0.02 mM and for NAD+ 0.11 mм, respectively. No remarkable loss of activity is observed following treatment with EDTA. The enzyme has been shown to react with a wide range of ethanolamines. A slight enrichment was obtained by ammonium sulphate precipitation. The name (-)-ephedrine: NAD+-oxidoreductase (deaminating) is proposed.
The Structures of Cassum unaquinones 1 and 2 from Zingiber cassumunar
Authors: Dinter Hildegard , Hänsel Rudolf , Pelter Andrew
Published: August 2018

Two novel pigments have been isolated from the lyophilised rhizomes of Zingiber cassumunar, wild ginger from Thailand. Their structures have been established by spectroscopic means as 2-methoxy-8(3,4-dimethoxyphenyl)-1,4-naphthaquinone (cassumunaquinone 1) and 2-methoxy- 8 (2,4,5-trimethoxyphenyl)-1,4-naphthaquinone (cassumunaquinone 2 ).
Isolation of Two Phenylbutadiene Dimers and One Monomeric 4-Phenylbut-3-ene from Zingiber cassumunar (roxb.)
Authors: Dinter Hildegard , Hänsel Rudolf , Pelter Andrew
Published: August 2018

Two arylbutadiene dimers of the 3-aryl-4-styrylcyclohexene series together with a novel C6-C4 monomer (2-(3,4-dimethoxystyryl)ethanol) have been isolated from Zingiber cassumunar. Due to their co-occurrence and the chemical similarity of one portion of the molecules, a possible biosynthetic relationship between the cyclohexene dimers and the phenylnaphthaquinones of Z. cassumunar, based on Diels-Alder reactions, is suggested.
The Induction of a Ribosomal Ribonuclease in Saccharomyces cerevisiae
Authors: Schulz-Harder Bemd , Kücherer Claudia
Published: August 2018

The ribosomal ribonuclease of yeast is induced after a withdrawal of glucose. Cycloheximide inhibits the synthesis of the enzyme under conditions of induction but antimycin shows no effect. Hence, the increase of the ribonuclease activity during growth of yeast is due to newly synthesized enzyme, and the induction does not depend on respiration.
Über den Gehalt an membrangebundenen und freien Ribosom en in Saccharomyceszellen bei verschiedenen Wachstums-Temperaturen / The Content of Membrane-Bound and Free Ribosomes in Growing Saccharomyces Cells at Different Temperatures
Authors: Wessel Jens , Lochmann Ernst-Randolf
Published: August 2018

The distribution of membrane-bound and free ribosomes was investigated at different temperatures in growing yeast cells. During duplication phases of the cell a changing pattern of the amount of membrane-bound and free ribosomes can be found at all temperatures investigated: at points where there is a maximum of membrane-bound ribosomes, one can always find a minimum of free ribosomes.

The ribosomal content is significantly higher at 30 °C than it is at 20 °C, and higher at 20 °C than at 40 °C, whereas the duplication time of the cells is only slightly longer at 40 °C, but extremely longer at 20 °C than at 30 °C.
Fluorescence Emission Properties of the Cation of 4-Aminopyrazole(3,4-d) pyrimidine, an Adenine Analogue: Evidence for Phototautomerism
Authors: Wierzchowski Jacek , Szczęśniak Marian , Shugar David
Published: August 2018

A study has been made of the emission spectra at room temperature, in aqueous and alcoholic media, of 4-aminopyrazolo(3,4-d)pyrimidine (APP) and some of its methylated derivatives. The cationic forms APPH+, N2-methyl-APPH+ and N7-methyl-APPH+ exhibit intense fluorescence un­der these conditions, the first two exhibiting excitation spectra which differ from the absorption spectra, pointing to the existence of a tautomeric equilibrium in the ground state. From the shape of the excitation spectra, and comparisons with methylated analogues in fixed tautomeric forms, it follows that the emission of APPH+ originates exclusively from the species N(2)-H,N(7)-H+, the other forms being non-fluorescent. The proportion of the emitting species, calculated from the ex­citation wavelength dependence of the quantum yield, is in good agreement with data for the ground state.

The emission spectrum of APPH+ in aqueous medium consists of two bands with λmax 360 nm and 430 nm, which exhibit identical excitation spectra, but are quenched to different extents by H3O+. The 430 nm emission band is absent in alcoholic media. A similar behaviour is exhibited by N7-methyl-APPH+, whereas the neutral form of this analogue exhibits only the 430 nm band. These results indicate that the long wavelength emission band of APPH+ originates from the rare tautomeric species N(7)-H formed in the excited state by photodissociation of the N(2)-H proton from the species N(2)-H,N(7)-H+. This is further confirmed by results obtained with the aid of the basicity method, as well as by salt efects in non-aqueous media. Consideration is given to the possibility of such processes occurring in other analogues of nucleic acid derivatives.
Small-Angle X-Ray Scattering Studies on the X-Ray Induced Aggregation of Malate Synthase Computer Simulations and Models
Authors: Zipper Peter , Durchschlag Helmut
Published: August 2018

Malate synthase undergoes an X-ray induced aggregation which can be monitored in situ by small-angle X-ray scattering; the analysis of scattering curves, taken at subsequent stages of aggregation, has led to the establishment of a tentative model for an aggregation in two dimensions (Zipper and Durchschlag (1980) Rad. and Environm. Biophys., in press).

This model was checked by comparison of appropriate theoretical curves with the experi­mental curves. The theoretical scattering curves for this comparison were obtained by weighted averaging over the scattering curves calculated for various species of hypothetical aggregates. Based on the approximation of the unaggregated enzyme particle by an oblate cylinder, the aggregates were assumed to be composed of 2, 3, 4 or 6 of such cylinders, associated side-by-side in one and later on in two linear rows. The weight fractions of the species were chosen so, that an optimum fit of the experimental mean radii of gyration and mean degrees of aggregation was achieved. The distance distribution functions calculated for the model are very similar to the functions derived from the scattering experiment. Cross-section Guinier plots of the scattering curves of the model reveal the occurrence of one and later on of two pseudo cross-section factors similar to those observed in the experimental scattering curves. The pseudo thickness factor of the model of the unaggregated particle is found to be retained in the model curves for all stages of aggregation. From these results it can be concluded that the model for the aggregation process is essentially consistent with the scattering behaviour of the aggregating enzyme. Small differences between the theoretical and experimental curves may be explained by the idealizations of the model. The comparison of theoretical curves for alternative models, assuming aggregation in three dimen­sions, suggests that these models are unlikely, though small amounts of three-dimensional aggregates cannot be ruled out completely.
The Structures of Sinapic Acid Esters and Their Metabolism in Cotyledons of Raphanus sativus
Authors: Linscheid Michael , Wendisch Detlef , Strack Dieter
Published: August 2018

Five sinapic acid esters were isolated from cotyledons of Raphanus sativus and have been iden­tified with the aid of electron impact (El)-, field desorption (FD)-mass spectrometry and NMR spectroscopy: 6,3′-disinapoylsucrose, sinapoylcholine (sinapine), 6-sinapoylglucoraphenine, 1-si- napoylglucose, and sinapoylmalate. Three of these derivatives are metabolically related in the se­quence sinapoylcholine →1 -sinapoylglucose →sinapoylmalate.
Highly Efficient Purification of the Labile Plant Enzyme 5-Aminolevulinate Dehydratase (EC 4.2.1.24) by Means of Monoclonal Antibodies
Authors: Liedgens Walter , Grützmann Rudi , Schneider Hansjörg A. W.
Published: August 2018

5-Aminolevulinate dehydratase (ALAD) from spinach (Spinatia oleracea) was isolated by affinity purification on an immunoabsorbens with a yield of 70 to 80% of the activity in the crude enzyme preparation. The enzyme eluted from the immunoabsorbens was pure as judged by poly­ acrylamide gel electrophoresis and is a hexamer with a subunit molecular weight of about 50000. Enzyme bound to the immunoabsorbens was able to synthesize porphobilinogen in a continuous manner. Owing to the lability of the enzyme and its low abundance in plant tissue, we have been unable to obtain similar yields of purified enzyme using classical purification procedures.

This highly efficient purification was made possible by using monoclonal antibodies as described by Köhler and Milstein (Nature 256, 495 (1975)). The availability of monoclonal antibodies meant that it was not necessary to purify the enzyme to homogeneity by classical means in order to raise an antiserum specific for ALAD. Sixteen clones of cells producing anti­ bodies against ALAD were selected. They all expressed a ϰ light chain but differed in the heavy chain class which was either γ1 or γ2a.

The availability of pure ALAD enzyme and of highly specific antibodies against the enzyme now enables us to answer questions concerning properties, localization, intercellular transport and evolution of ALAD. It is clear that the technique used and the questions asked are not restricted to ALAD.
Partial Purification and Some Properties of a Hydroxycinnamoyl Glucosyltransferase from Tomato Fruits
Authors: Fleuriet A. , Macheix J. J. , Suen R. , Ibrahim R. K.
Published: August 2018

A glucosyltransferase was isolated from immature “cherry” tomatoes and was partially purified (200-fold) by ammonium sulphate precipitation and successive chromatography on Sephadex G-100 and DEAE-cellulose columns.

The enzyme utilised the free hydroxycinnamic acids and UDP-glucose in the formation of their respective glucosides (pH 8.0) and glucose esters (pH 7.0); but did not accept the CoA thiolesters of HCAs in the presence of glucose-1-phosphate. The constant glucoside/glucose ester ratio observed during purification suggests that both reactions are catalysed by the same enzyme.

The Km values for ρ-coumaric, caffeic, ferulic and sinapic acids were 0.8, 1.5, 1.4 and 2.5 μᴍ, respectively. With ferulic acid as substrate, the Km value for UDPG was 10 μᴍ. The enzyme required an -SH group for activity and the reaction was strongly inhibited by EDTA, divalent metal ions and UDP.
"Flavanone Synthase" in Oat Primary Leaves Time Course and Distribution at the Tissue and Subcellular Level
Authors: Fuisting Klaus , Weissenböck Gottfried
Published: August 2018

“Flavanone Synthase” (FS) isolated from oat primary leaves shows maximal activity in the differentiating zone of five day old leaves. Activity of FS is distributed in both the upper and lower epidermis, but dominant in the mesophyll. After fractionation of mesophyll protoplasts of Avena by differential centrifugation, FS activity could only be detected in the “cytosol” and not in intact chloroplasts or other particulate fractions.
A Convenient Method for the Preparation of Pheromones from Inexpensive Starting Materials
Authors: El-Rabbat Nawal A. , Mangold H. K.
Published: August 2018

-9-Tetradecenoic acid was isolated from the total fatty acids of beef tallow. (Z)-9-Tetradecenol, (Z)-9-tetradecenyl acetate and (Z)-9-tetradecenal, compounds known to function as sex attractants in various insect species, were prepared from this fatty acid.
Low Affinity Calcium Binding Sites of the Calcium Transport ATPase of Sarcoplasmic Reticulum Membranes
Authors: Hasselbach Wilhelm , Koenig Vera
Published: August 2018

Calcium binding sites having low affinity constants of < 103 ᴍ-1 were titrated in native sarcoplasmic reticulum vesicles as well as in lipid deprived membranes and in the isolated calcium transport ATPase. Short time calcium binding measurements and the determination of the calcium binding heat allow to distinguish low affinity calcium binding sites located on the external surface of the sarcoplasmic reticulum membranes from those present in the section of the transport molecule directed to the vesicular space. The same number of internal binding sites was found for preparations deprived of their lipid content as well as of preparations depleted of their lipids and of their accessorial proteins. Magnesium interferes with calcium binding to the external as well as to the internal low affinity calcium binding sites. The implications of the existence of the low affinity calcium binding sites in the internal section of the calcium transport ATPase are discussed.
Effect of Viscous Solvents and Monomer on Conservation of Intact and Immobilized Chloroplasts
Authors: Kaetsu I. , Fujimura T.
Published: August 2018

O2 evolution activity of PS II in chloroplast stored in buffer including various supercooling solvents was studied. Viscous solvents such as polyethylene glycol (PEG) was remarkably effective for the increase of lifetime of intact chloroplast. Lifetime of immobilized chloroplast by means of radiation polymerization was prolonged more than 40 days in buffer including PEG 70% (v/v). It was found that viscous solvents having PEG units in molecular chain were effective and methoxypolyethyleneglycol methacrylate monomer (M-23G) was most suitable as a im­mobilization carrier. The immobilized chloroplast with M-23G retained the high activity yield more than 30 days in buffer including PEG.
Infection of Murine T Lymphocytes with Lymphocytic Choriomeningitis Virus: Effect of Age of Mice on Susceptibility
Authors: Tijerina Rolando , Löhler Jürgen , Chaturvedi Umesh C. , Lehmann-Grube Fritz
Published: August 2018

Infectious T lymphocytes were determined in thymuses and spleens of mice acutely infected with LCM virus. Such cells appeared in newborn animals, but their numbers declined when the age at infection increased and none were found in adult mice. Either susceptibility to LCM virus is associated with some degree of immaturity or the probability of murine T lymphocytes to encounter the virus as an infectious entity rather than an immunogen is higher in very young than in immunologically mature mice.
Ecdysteroid Titres during Autonomous Metamorphosis in a Dermestid Beetle
Authors: Delbecque Jean-Paul , Sláma Karel
Published: August 2018

The larvae of Dermestes maculatus are able to undergo several moults in complete absence of the cephalic and prothoracic neuroendocrine system, showing thus spontaneous metamorphosis. Measurements of ecdysteroid contents by radioimmunoassay methods have revealed distinctive larval, prepupal and pupal ecdysteroid peaks, as found in other species where development requires frequent stimulation by the centrally produced hormones. Mass fragmentographic analysis has indicated that more than 80% of the ecdysteroids detected by the radioimmunoassay during the peaks consists of ecdysterone.

The prothoracic glands (PG) of D. maculatus larvae are located in the head capsule and in the cervical region. They can be separated from the body by neck-ligation. Only the larval peak of ecdysterone can be correlated with PG function. The prepupal and pupal peaks of ecdysterone are not produced by the central neuroendocrine system. The isolated abdominal fragments of larvae and pupae positively produce ecdysteroids in the course of their independent development, but this synthesis has been subnormal and occasionally delayed in time. In contrast, the isolated thoracic fragments produce well synchronized peaks of ecdysterone and this does not depend on the PG. It thus appears that some thoracic tissue other than PG is able to maintain the physiological concentration of ecdysterone by means of a concentration-dependent feed-back mechanism.

Due to spontaneous metamorphosis and extremely good survival we have succeeded to induce in this species: a) premature formation of the prepupal cycle of ecdysterone synthesis in the penultimate larval instar by ligation; b) inhibition and delay of the prepupal peak by means of juvenoid treatments; c) reappearance of the prepupal peak in the inhibited “permanent larvae” by exogenous administration of ecdysterone, or; d) modification of the pupal peak by a qualitatively new pupal-pupal one after juvenoid treatments. These experimental transformations of the ecdysterone peaks have suggested that the kind and nature of the peaks are closely related to nature and stage of the ontogenetic development. We therefore believe that the process of larval-pupal reprogramming has occurred in this species long before the increase of ecdysterone titer in the body. Both the prepupal and pupal peaks do not represent a cause but they show to be rather consequences of the developmental programming. Further features associated with possible physiological role of ecdysteroids in insect development have been briefly discussed.
Temperature-Dependent Staining Reaction of Chromatin by Alcian Blue
Authors: Stockert J. C. , Juarranz A.
Published: August 2018

After treatment with Alcian blue at high temperatures, nuclei from chicken blood smears showed an intense stai­ning rection, which proved to be dependent on the DNA content of chromatin. The possibility that interactions bet­ween the phthalocyanine chromophore and unpaired bases accounts for this temperature-dependent staining of chro­matin is briefly discussed.
Freeze-Fracture Evidence of Differences between Membranes of Perialgal and Digestive Vacuoles in Paramecium bursaria
Authors: Meier Renate , Reisser Werner , Wiessner Wolfgang , Lefort-Tran Marcelle
Published: August 2018

Measurements of particle densities on the two freeze-fracture faces of digestive and perialgal vacuole membranes in green and aposym biotic Paramecium bursaria Ehrbg. show distinct differences between the P-faces of both membrane types. The distribution of particle densities is more homogenous on the P-faces of perialgal vacuole membranes than on the P-faces of digestive vacuole membranes. Possibly homogeneity among peri­ algal vacuole membranes reflects the stability of perialgal vacuoles during their life cycle. Perhaps lysosomes cannot fuse with them.
Zum Farbunterscheidungsvermögen der Honigbiene bei niedrigen Umgebungshelligkeiten / Colour Discrimination of the Honey Bee at Low Light Intensities
Authors: Pflughöft Gerhard
Published: August 2018

Homing foragers of the honey bee (Apis mellifera carnica) were tested for discrimination of colour marks presen­ted to them at the hive entrance. At a low rate of natural il­lumination the bees were not able to distinguish the coloured (yellow, blue) marks from those with a corresponding gray. However, their general orientation was not disturbed. From this the conclusion is drawn that at low light intensities bees have an achromatic vision besides their known co­ lour vision at higher intensities.
Denaturation and Renaturation of Bovine Liver Glutamic Dehydrogenase after Dissociation in Various Denaturants
Authors: Müller Klaus , Jaenicke Rainer
Published: August 2018

Oligomeric glutamic dehydrogenase from bovine liver is dissociated to inactive monomers (Mr = 56 000) under a wide variety of conditions: 3 ≥ pH ≥ 12, 6 ᴍ guanidine · HCl, 6 ᴍ urea, 0.2% sodium dodecylsulfate. High hydrostatic pressure (< 1 kbar) only affects the association equilibrium of the native hexamer to higher polymers. The respective reaction volume (ΔV=28 ± 5 ml · mol-1 at 298 K, 1 bar) is linearly dependent on temperature and pressure. At p > 1.5 kbar dissociation of the hexamer occurs; this reaction is accompanied by irreversible deactivation.

Depending on the denaturant applied for the monomerization, the final conformational stale of the polypeptide chain differs widely regarding its residual structure.

As taken from laser light scattering measurements the rate of dissociation at pH 1.8 follows first order kinetics with a rate constant k1 = 0.42 ± 0.06 s-1.

In the range of the oligomer ⇌ monomer transition, dissociation is accompanied by irreversible aggregation leading to inactive high molecular weight material. At low concentration (c < 5 µg/ml) this side reaction can be slowed down, so that the reconstitution of the enzyme can be monitored using spectroscopic techniques. Concentration dependent stopped-flow experiments prove the regain of fluorescence to be a rapid first order process; the respective half-times at pH 7.4 are τ1/2 = 2.0 ± 0.5 ms and 0.7 ± 0.2 ms for the “renaturation” from 6 ᴍ guanidine · HCl, pH 6, and pH ~ 2, respectively.

The product of reconstitution shows the fluorescence and circular dichroism pattern characteristic for the native enzyme. However, no reactivation can be achieved under any of the following conditions: optimum protection against chemical modification; variation of enzyme concentration, temperature, and hydrostatic pressure; addition of specific ligands such as coenzymes, substrates, ADP, membrane constituents (cardiolipin, electron transfer particles ETPH). Obviously, the “renaturation” (D → N) of glutamic dehydrogenase is governed by a side reaction according to

N → D ⇌ R → A

which causes aggregation of intermediates R instead of reconstitution of the native enzyme.
The Activation of Ribulose-1,5-bisphosphate Carboxylase-Oxygenase from Spinach by Oxygen / Changes of the Enzyme Conformation during Air-Argon Transitions
Authors: Wildner Günter F. , Sane Prafullachandra V. , Henkel Jürgen
Published: August 2018

The effect of oxygen on ribulose-1,5-bisphosphate carboxylase-oxygenase from spinach was in­vestigated. Both activities were deactivated by removal of oxygen and reversibly reactivated by oxygenation of the enzyme solution. The change in enzyme activities was accompanied by conformational changes as studied by the use of intrinsic and extrinsic fluorescent probes.

The analysis of cysteine sulfhydryl groups accessible to 5,5′-dithiobis-(2-nitrobenzoic acid) revealed that the number of these groups changed with the oxygen concentration. The kinetic of the exposure of eight cysteine residues was similar to the loss of enzyme activities. The modification of these groups with 5,5′-dithiobis-(2-nitrobenzoic acid) caused almost complete loss of both the activities.

The enzyme isolated from a photolithotrophic organism, Chromatium vinosum, was not affected by oxygen removal. During air - argon transitions, neither the enzyme conformation nor the number of accessible sulfhydryl groups changed.
Cytotoxicity of Cobra (Naja naja kaouthia) Venom on Rabbit Red Blood Cells and S-180 Tumor Cells in the Presence of Tetracaine, Lidocaine and Procaine
Authors: Li Ping-Lu
Published: August 2018

The cytocidal action of Naja naja kaouthia venom on rabbit red blood cells and S-180 tumor cells treated with local anesthetics (tetracaine, lidocaine and procaine) were studied. The S-180 cells were more sensitive to the venom than the red blood cells which required albumin for efficient hemolysis in the 10 minute assay. All three local anesthetics at lower concentrations protected both cell types against venom hemolysis. At higher concentrations the local anesthetics enhanced the cell lysis to 100%. The effectiveness of the local anesthetics for both the inhibition and enhancement phases of cytotoxicity was tetracaine > lidocaine > procaine. This is the same order as their anesthetic effectiveness, lipid solubility and their protein binding.
Water Budget in Larvae of Semiadalia undecimnotata Schn. Studied with Tritiated Water
Authors: Buscarlet L. A. , Ferran A. , Larroque M.
Published: August 2018

The rates of water vapor entry, body water clearance and the net loss of water in larvae of Semi­ adalia undecimnotata (3rd and 4th stage) of different weights were determined from observed changes in the mass of body water and its tritium content for each of several relative humidities (RH) in ambient air.

The water clearance and vapor entry rates as a function of weight increases from emergence to the middle of the stage and then remains constant. The vapor entry rate increases with RH while the clearance rate is independant of RH. The permeability of the cuticle has not the same value in the inward and in the outward direction. The permeability to body water escape is not affected by RH and reaches a maximum at the middle of the stage. The inward permeability does not depend on weight and increases appreciably as RH reaches saturation.

One day of starvation affected these movements of water most in larvae at the middle of their stage.

These results are discussed in relation to some physiological data concerning the cuticular struc­ture and its evolution with age.
A Hydrodynamic Model of Cerebrospinal Fluid Flow in Man
Authors: Wüst Rolf , Kolberg Trygve , Palma Alvaro , Palma Alfredo
Published: August 2018

A hydrodynamic bi-compartmental model for the cerebrospinal fluid (CSF) flow in humans is presented which combines anatomical and physiological conditions in the central nervous system with results of special radioisotope diagnostic techniques. Normal and disturbed conditions, the diagnostic methods and the results are explained. A differential equation for the time behaviour of regional radioisotope concentrations is derived by applying to the model mathematical procedures which are familiar from the description of radioactive decay series, or reaction kinetics of chemical or pharmaceutical processes. The solutions are analysed and discussed with respect to findings of isotope diagnostics, and parameters for the complete and quantitative evaluation of CSF flow systems are derived. A system factor is introduced for classification purposes and, in conjunction with basic principles of hydrodynamics, is used to postulate a similarity law of CSF flow systems. The diagnostical and therapeutical value of the model for analysis and simulation of CSF flow systems is discussed. Practical applications to other disciplines are proposed.
Biochemical and Electronmicroscopic Investigations on Helix pomatia Collagen
Authors: Schmut O. , Roll P. , Reich M. E. , Palm W.
Published: August 2018

The skin of Helix pomatia was investigated by biochemical methods and electronmicroscope. Biochemical investigations showed that Helix pomatia collagen represents a methionine-lacking collagen resistant to CNBr-cleavage. Electron microscopic studies showed a cross striation pattern of 5 3 -5 7 nm.
Die Flavonoide der Samen von Medicago × varia Martyn c. v. Cardinal (Fabaceae) /The Seed-Flavonoids of Medicago × varia Martyn c. v. Cardinal (Fabaceae)
Authors: Gehring Eberhard , Geiger Hans
Published: August 2018

Medicago x varia Martyn c. v. Cardinal (Fabaceae) The Seed-Flavonoids of Medicago x varia Martyn c. v. Cardinal (Fabaceae) Medicago x varia c. v., Fabaceae, Flavonoids, 5-Methoxyflavones, 5-Methoxyflavonols From the seeds of Medicago x varia Martyn c. v. Cardinal have been isolated twenty flavonoids, including four 5-methoxyflavonoids. Four compounds have been obtained the first time from a natural source. The constitution of all compounds is prooved.
Induced Isoflavonoids of Erythrina sandwicensis
Authors: Ingham John L.
Published: August 2018

Two new phytoalexins isolated from the fungus-inoculated leaflets of Erythrina sandwicensis have been identified as (—)-6aS; 11 aS-3,6 a,9-trihydroxy-10-isopentenylpterocarpan (sandwicar-pin) and (—)-6aR; 11 aR-3-hydroxy-9-methoxy-10-isopentenylpterocaipan (sandwicensin). These compounds co-occur with several known pterocarpan (demethylmedicarpin, 3,6a,9-trihydroxy-pterocarpan, phaseollidin and cristacarpin) and isoflavan (demethylvestitol and isovestitol) deriva­ tives. The preparation and spectral (UV, MS) characteristics of 3-methoxy-9-hydroxy-10-isopen-tenylpterocarpan are also described.
Competition of Pyridoxal 5'-Phosphate with Ribulose 1,5-Bisphosphate and Effector Sugar Phosphates at the Reaction Centers of the Spinach Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase
Authors: Vater Joachim , Gaudszun Thomas , Schamow Harald , Salnikow Johann
Published: August 2018

The Stimulation of the carboxylase reaction by effectors of ribulose 1,5-bisphosphate carboxyl­ ase/oxygenase displays higher sensitivity towards pyridoxal 5'-phosphate inhibition than the catalytical process itself.

Pyridoxal 5'-phosphate binding to the enzyme is not affected by the modulators 6-phospho-gluconate and fructose 1,6-bisphosphate at low concentrations at which these agents stimulate the carboxylation rate.

At higher concentrations these sugar phosphates protect the enzyme against pyridoxal 5'-phos-phate inhibition in a similar fashion like the substrate ribulose 1,5-bisphosphate.

Such protection experiments in combination with spectrophotometrical studies of pyridoxal 5'-phosphate binding demonstrate two binding states of ribulose 1,5-bisphosphate at the reaction centers of the enzyme with different requirements for Mg2+. 6-Phosphogluconate functions as protector only in the presence of Mg2+.

Our results imply a competition between pyridoxal 5'-phosphate and substrate or effector sugar phosphates at the reaction centers of the spinach carboxylase. It is proposed that the pyridoxal 5'-phosphate inhibition of the stimulatory activity of these effectors originates from a modification of the regulatory sites of the enzyme caused by pyridoxal 5'-phosphate binding to the catalytical sites.
Tropomyosin-Troponin-Induced Changes in the Partitioning of Free Energy Release of Actomyosin-Catalyzed ATP Hydrolysis as Measured by ATP-Phosphate Exchange
Authors: Dancker Peter
Published: August 2018

ATPase activity and ATP-Pi exchange of unregulated (without tropomyosin-troponin) and regulated (with tropomyosin-troponin) acto-HMM were measured in media containing 0.2 mg/ml actin, HMM, and (when present) tropomyosin-troponin, 2 mM MgCl2, 10 m M KCl, 2 mM NaN3, 10 mM Pi(pH 7.0), 3 mM ATP. The following mean values for ATPase activity and for the rate of incorporation of P, into ATP (each per mg HMM and per min) were obtained: unregulated acto-HMM 0.33 nmol Pi and 0.33 nmol Pi, regulated acto-HMM 0.54 nmol Pi and 1.06 nmol P*. The ratio of P4 incorporation rate to ATPase activity was 1.01 × 10-3 for unregulated and 2.02 × 10-3 for regulated acto-HMM. From these ratios and from the overall free energy change of ATP hydrolysis it was calculated that under the prevailing experimental conditions in unregulated acto-HMM 62% and in regulated acto-HMM 66% of the free energy change of ATP hydrolysis occurs after the release of phosphate from actomyosin. It is probably this part of the free energy change that is used by the muscle for the performance of work.
The Effect on Ammonium Chloride on the Kinetics of the Back Reaction of Photosystem II in Chlorella fusca and in Chloroplasts in the Presence of 3-(3,4-Dichlorophenyl)-1 ,1 -dimethylurea
Authors: Vierke Gerhard
Published: August 2018

The effect of NH4Cl on the kinetics of the back reaction of photosystem II as derived from luminescence measurements was investigated in dark adapted Chlorella in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) at different temperatures. The kinetics of the back reaction which, under these conditions, leads to the reduction of the S2 state by the primary electron acceptor Q- of photosystem II was observed to be considerably slowed down in the presence of NH4Cl.

Analysis of the kinetic results in the light of the theory of the back reaction developed by Mar and Roy (J. Theor. Biol. 48, 257-281 (1974)) revealed two opposite effects of NH4Cl to be present simultaneously:

1) The enthalpy of activation of the back reaction was lowered (catalyzing effect of NH4Cl)

2) The frequenca factor which indicates the number of collisions of the reacting molecules in the membrane per second is largely decreased (inhibitory effect of NH4Cl).

This reduction of the mobility of the recombining species of the back reaction is the predominant effect of NH4Cl. It is suggested that this effect is due to a change of the conformational state of the membrane induced by dissolution of relative large amounts of NH? within the lipid phase of the thylakoid membrane. This hypothesis is supported by the observation that the value of the exciton yield of the back reaction changes upon addition of NH4Cl.
Light-Induced Valence Change of a Manganese-Containing Chlorophyll Derivative
Authors: Lazar Günter
Published: August 2018

K3(Mn-(III)-chlorin e6) acetate, a water-soluble chlorophyll derivative with manganese as central atom was prepared. The influence of reducing agents, light, and bicarbonate on the oxida­ tion states of manganese in the chlorin complex was investigated. In alkaline solutions the central Mn3+ was reducible to Mn2+. The illumination of the partially reduced complex first accelerated the reduction (light reduction: Mn3+ → Mn2+), which was then followed by a strong reoxidation (light oxidation: Mn2+ →* Mn3+) continuing after switching off the light. This redox effect of light was obtained only in presence of hydroxylamine as reducing agent. Illumination time, intensity, and frequency had an influence on this effect. In the light/dark change the process was reversible. In regard to the requirement of manganese for the photosynthetic oxygen evolution the observed valence change of manganese in the chlorin complex was compared to the supposed reaction mechanism on the donor side of photosystem II.
Effect of Irradiation and Immobilization on Spinach Chloroplast Activities
Authors: Fujimura T. , Yoshii F. , Kaetsu I. , Inoue Y. , Shibata K.
Published: August 2018

The effect of y-ray irradiation and immobilization by means of radiation polymerization on PS II activity (O2 evolution) of isolated chloroplasts from spinach was investigated. Reduction of O2 evolution activity by irradiation was small at lower temperatures below – 24 °C, but the activity decreased slightly by freezing at extremely low temperature below –78 °C. So the optimum low temperature range for the treatment was observed. The immobilized chloroplast in a hydrophilic polymer matrix showed the stable duration of O2 evolution activity more than 700 h at 4 °C . Thermo-stability of chloroplast was also improved greatly by immobilization. The active center of PS II in immobilized chloroplasts was retained even after 60 min standing at 50 °C.
Construction of Phylogenetic Trees By Pattern Recognition Procedures
Authors: Sharaf Muhammad Abdallah , Kowalski Bruce R. , Weinstein Boris
Published: August 2018

The sequence of a protein can be graphed as a discrete function and a cross-correlation between any two such number sets produces a similarity score. The scores are used to prepare a phylogenetic tree involving hierarchical cluster analysis, non-linear mapping, and minimal spanning routines. Changes are suggested in the sequences of cytochrome c’s from Mediterranean fruit fly, locust, and rattlesnake. The method is faster than existing procedures and does not require human intervention at any stage.
Phenolics from Larix Needles. XV. High-Performance Liquid Chromatography of L. gmelinii Flavonoids
Authors: Niemann Gerard J.
Published: August 2018

From needles of Larix gmelinii sixteen flavonoids were isolated and identified. The main flavonoids had been analyzed before, eight minor ones were identified as quercetin-3-glucoside, isorhamnetin-3-glucoside and -3-ara-binoside, a somewhat lipophilic kaempferol-3-glucoside derivative, apigenin-7-glucoside, laricitrin-3-rutinoside and laricitrin-and syringetin-3-(p-coumarylglucoside).
Kinetics of the Back Reaction of Photosystem II as Derived from Delayed Light Emission in the Presence of DCMU and the Conformational State of the Thylakoid Membrane
Authors: Vierke Gerhard
Published: August 2018

It is shown that the kinetics of the back reaction of photosystem II in the seconds time range as derived from the luminescence decay curve in the presence of DCMU is controlled by the internal pH of the thylakoids. Modifications of the conformational state of the photosynthetic membrane while leaving the internal pH unchanged, however, reaction.
Reversed Phase High Performance Liquid Chromatography of Essential Oils
Authors: Strack Dieter , Proksch Peter , Gülz Paul-Gerhard
Published: August 2018

A reversed phase high performance liquid chromatographic procedure for the separation of essential oils is described. Applying water-acetonitrile elution systems on octyl and octadecylsilane- bonded silica, complex mixtures of sequiterpenes and oxygenated volatile constituents can be resolved, comparably to the quality of gas chromatographic analysis. Photometrical detection at different wavelengths can be an important parameter in optimizing the separation of essential oil constituents. The application of the described method is demonstrated with naturally occurring mixtures of terpenes from leaves of Cistus ladanifer.
Isolation of the Phytochrome Chromophore. The Cleavage Reaction with Hydrogen Bromide
Authors: Rüdiger Wolfhart , Brandlmeier Thomas , Bios Inge , Gossauer Albert , Weller Jens-Peter
Published: August 2018

The cleavage of the bilin chromophore from C-phycocyanin with hydrogen bromide yields 3E-configurated phycocyanobilin (4) as the major and 3 Z-configurated phycocyanobilin (5) as the minor reaction product. The reaction of synthetic 3E-configurated phytochromobilin (2) with hydrogen bromide and methanol leads only to a methanol adduct at the C-18 side chain (7) whereas the same reaction with the 3Z-configurated phytochromobilin (3) leads to 7 and 2. The bilin chromophore was cleaved also from phytochrome after preparation of phytochromobilin peptides. The detection of 2 and 7 suggested that 3Z-and 3E-configurated phytochromobilin were the primary products of cleavage from phytochrome. A reaction scheme is given which can explain the results of the reaction with hydrogen bromide and methanol.
Superoxide-and Ethane-Formation in Subchloroplast Particles: Catalysis by Pyridinium Derivatives
Authors: Elstner E. F. , Fischer H. P. , Osswald W. , Kwiatkowski G.
Published: August 2018

Oxygen reduction by chloroplast lamellae is catalyzed by low potential redox dyes with E′0 values between -0 .3 8 V and -0 .6 V. Compounds of E′0 values of -0 .6 7 V and lower are inactive. In subchloroplast particles with an active photosystem I but devoid of photosynthetic electron transport between the two photosystems, the active redox compounds enhance chlorophyll bleaching, superoxide formation and ethane production independent on exogenous substrates or electron donors. The activities of these compounds decrease with decreasing redox potential, with one exception: 1-methyl-4,4′-bipyridini urn bromide with an E′0 value of lower -1 V (and thus no electron acceptor of photosystem I in chloroplast lamellae with intact electron transport) stimulates light dependent superoxide formation and unsaturated fatty acid peroxidation in sub­ chloroplast particles, maximal rates appearing after almost complete chlorophyll bleaching. Since this activity is not visible with compounds with redox potentials below -0 .6 V lacking the nitrogen atom at the 1-position of the pyridinium substituent, we assume that 1 -methyl-4,4′-bi-pyridinium bromide is “activated” by a yet unknown light reaction.
Changes Induced by Pre-Fixation in Polycation Bacteriolysis and Surface Alterations Matching the Model of Wall Picnosis in Cell Lysis
Authors: Popescu Alexandru , Antohi Stefan , Trasculescu Stefan , Aurescu Adriana , Manolescu Nicolae , Ciocnitu Victor
Published: August 2018

Pretreatments of B. subtilis and S. aureus cells with lower concentrations of fixative agents, led to modifications in bacteriolytic effect exerted by polyarginine and protamine: Glutaraldehyde blocked polycation bacteriolysis while formaldehyde and osmium tetroxide (OSO4) having no influence on polyarginine action, increased constantly the cell sensitivity to protamine in lower doses otherwise nonlytic; the sensitizing action also resulted in the extension of protamine bacteriolytic pattern including several staphylococcal strains; higher bacteriolytic doses of protamine were contrastively unable to lyse OSO4 prefixed cells and gave an inconstant lytic value with formaldehyde treated bacteria. With higher concentrations, OSO4 preserved intactly its sensitizing action while formaldehyde displayed a decrease in its ability to sensitize B. subtilis cells to the lytic effect of protamine. Scaning electron microscopy of polycation treated cells showed prelytic lesions as surface granulations, shape and size modifications and cell splits. The interpretation of the results in terms of intra-and intermolecular adducts accompanied by con­ formational changes in surface macromolecules is discussed. It is concluded that the results match the model of polycation bacteriolysis by wall multizonal picnosis leading to surface splits and thereby triggering cell-lysis.
Toxizität und cytostatische Wirkung von PtCl2(NH3)2 nach i. v. und intratumoraler Injektion / Toxicity and Cytostatic Effect of PtCl2(NH3)2 after i. v. and i. t. Injection
Authors: Wenzel M. , Schneider M. , Bier J.
Published: August 2018

oxizität und cytostatisch e W irkung von PtCl2(NH3)2 nach i. v. und intratumoraler Injektion Toxicity and Cytostatic Effect of PtCl2(NH3)2 after i. v. and i. t. Injection In tumor bearing mice intratumoral injection of PtCl2(NH3)2-solution increases the cytostatic effect while decreasing its toxicity in comparison to i. v. injection. In­ tratumoral injections of water-in-oil emulsions of the platin-compound are less cytostatic but have a consider­ ably lower toxicity.
Hydrogen Evolution Catalyzed by Hydrogenase in Cultures of Cyanobacteria
Authors: Hallenbeck Patrick C. , Kochian Leon V. , Benemann John R.
Published: August 2018

Cultures of Anabaena cylindrica, grown on media containing 5 mᴍ NH4Cl (which represses heterocyst formation), evolved hydrogen after a period of dark incubation under an argon atmosphere. This hydrogen production was not due to nitrogenase activity, which was nearly undetectable, but was due to a hydrogenase. Cultures grown on media with tungsten substituted for molybdenum had a high frequency of heterocysts (15%) and inactive nitrogenase after nitrogen starvation. The hydrogenase activity of these cultures was three-fold greater than the activity of non-heterocystous cultures. The effects of oxygen inhibition on hydrogen evolution by hetero-cystous cultures suggest that two pools of hydrogenase activity exist - an oxygen sensitive hydrogen evolution in vegetative cells and a relatively oxygen-resistent hydrogen evolution in heterocysts. In either case, inhibition by oxygen was reversible. Light had an inhibitory effect on net hydrogen evolution. Hydrogen production in vitro was much higher than in vivo, indicating that in vivo hydrogenase activity is limited by endogenous reductant supply.
Chemische Analyse und Struktur des Poliovirus. I. Cystein/Cystin Gehalt, vollständige Aminosäureanalyse und Hydrophobizität von Poliovirus und seinen natürlichen leeren Kapsiden / Chemical Analysis and Structure of Poliovirus. I. Cysteine/Cystine Content, Complete Amino Acid Analysis and Hydrophobicity of Poliovirus and Its Naturally Occurring Empty Capsids
Authors: Heukeshoven Jochen , Demick Rudolf
Published: August 2018

The cysteine content of poliovirus particles and naturally occuring empty capsids was determined by two methods: (1) reaction with vinylpyridine and subsequent amino acid analyses and (2) treatment with 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) and measurement in the change of absorption. Both methods were performed under dissociating conditions in order to expose all sulfhydryl groups. Poliovirus, type 1, strain Mahoney, contains 10-11 cysteine/cystine residues per protomer, irrespective of the use of virus particles or empty capsids. Poliovirus, type 3, strain Saukett, contains 12-13 cysteine/cystine residues per protomer. Poliovirus particles are completely free of disulfide bridges, whereas empty capsids contain 2-4 cystine residues/protomer. No sulfhydryl groups are present on the surface of the virus particle, because of lack of reaction with DTNB.

The tryptophan content was determined to be 13 ± 1 residues/protomer. By amino acid analysis under controlled hydrolyzing conditions 12 residues/protomer were found, whereas formylation in hydrochloric acid/formic acid revealed 14 residues/protomer; 13 tryptophan residues were calculated from the tyrosine-tryptophan relation and the optical density at 293.5 nm and 280 nm.

The following parameters of poliovirus particles were calculated from the improved and complete amino acid analysis and the cysteine and tryptophan content:

1. The molecular weight of a protomer to be 92 700 ± 900 Dalton and of the poliovirus particle, type 1, strain Mahoney, to be 7.97 × 106 Dalton.

2. The relative hydrophobicity of the poliovirus polypeptide to be 1.18.

3. The extinction coefficients of poliovirus E1%
260 = 7 4 and of empty capsids E1%
280 = 16.2 ± 0.2.