bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Tetrodotoxin, Veratridine and Tetraethylammonium Chloride on the Receptor Potential of the Crayfish Photoreceptor Cell
Authors: Stieve H. , Malinowska T. 
Published: August 2018

The effect of three drugs on the receptor potential (ReP) of the crayfish retina measured with external electrodes was tested.
1. Tetrodotoxin (TTX) (1·10-6 g/ml and 1·10-5 g/ml) showed only slight effects on the receptor potential (Table I and II).
2. Veratridine (VERA) (1·10-5 g/ml) showed only small effects of the same type as TTX but a little stronger on the receptor potential which became obvious especially in the period after washing out the drug (Table III).
3. Tetraethylammonium (TEA) (5 mм/1) caused a decrease of the height of the receptor potential without influencing the repolarizing phase (decrease-time £2) markedly (Table IV).
The results can be interpreted as follows:
1. The permeability increase for sodium, calcium and magnesium, whidi causes the rising phase of the receptor potential in the crayfish photoreceptor cell is of different nature than the increase of the sodium permeability in the squid nerve, or the sites of the sodium channel are not accessible for the TTX in the photoreceptor cell. This is shown by the experiments with TTX and VERA.
2. AU the changes of the receptor potential which are caused by TEA can be explained by assuming that the permeability for potassium in the dark is lowered by TEA and that in the course of the normal receptor potential an increase of potassium permeability, which causes the decreasing repolarizing phase of the receptor potential, does not occur.
Stimulierung von Kulturen embryonaler Rattenzellen durch Kälberserum. V. Verhalten der Inosit- und Cholinphospholipide / Stimulation of Embryonic Rat Cells by Calf Serum. V. Metabolism of Inositol- and Choline Phospholipids
Authors: Ristow Hans-Jürgen , Frank Werner , Fröhlich Margitta 
Published: August 2018

Embryonic rat fibroblasts were accumulated in G1-phase by incubation in serum-free medium and subsequently stimulated by the addition of calf serum. Using 3H-inositol and 14C-choline as label for phospholipids, the following results have been obtained:
1. Within a few minutes after stimulation up to 20 per cent of total phosphatidyl 3H-inositol is released from the membranes of prelabelled cells. This could not be detected with 14C-choline- prelabelled phospholipids.
2. Incorporation of 3H-inositol into phosphatidyl inositol, but not the uptake into the acid-soluble cell pool, is increased 30 and 45 min after stimulation by a factor of 2.8 and 3.3 respectively. Incorporation of 14C-choline at that time is significantly lower (2.0 and 1.6 respectively).
3. Incorporation of 32P inorganic phosphate into the lipid fraction of stimulated cells is 8.9 times higher after 10 min as compared with the controls.
Der Einfluß von ʟ-Äthionin auf Blutungsrate und Ionentransport im Blutungssaft / The Influence of ʟ-Ethionine on Bleeding Rate and Ion Transport within the Bleeding Sap
Authors: Lorenz H. 
Published: August 2018

The bleeding rate as well as transport of K+, NO3
- and PO4
--- within the bleeding sap of corn plants (Zea mays) has been studied in intervals after raising the nitrate concentration of the nutrient solution from 5 to 10 meq/1.
Acceleration of the exudation process in response to increased nitrate supply is accomplished after a lag phase. During this lag phase ʟ-ethionine causes a marked stimulation of bleeding sap exudation.
A very close correlation (coefficient of correlation r = 0,996) was found between bleeding rate and phosphate transport within the bleeding sap, whereas transport of K+ (r=0,868) and NO3
- (r=0,773) is not that closely correlated. Because phosphate is translocated to the Xylem after it has been metabolized in a series of organic phosphorous compounds it is concluded that the exudation process is primarily linked to oxidative phosphorylation in the root, which is apparently stimulated by ethionine after a lag period. Acceleration of respiratory chain phosphorylation may be brought about by increasing the amount of phosphate acceptors.
The Association between Purine Nucleosides and Benzene in Aqueous Solution, Studied by Proton Magnetic Resonance and Nuclear Overhauser Enhancements
Authors: Lüdemann Hans-Dietrich , Goldammer Eberhard v. 
Published: August 2018

Abstract
The dependence of the PMR spectra of three purine nucleosides (inosine, adenosine and deoxyadenosine) on temperature, concentration and addition of benzene (0.12 molal) has been investigated in aqueous solution. The interaction of benzene with the nucleosides is deduced from the spectra. Enthalpies of self association have been determined as 2.2± 0.1 kcal·mole-1 for dA and I. The corresponding values obtained for hetero association with benzene are 2.7 ± 0.2 kcal·mole-1 for dA and 2.3± 0.2 kcal·mole-1 for I. The formation of edge to face complexes is concluded. Additional evidence for this type of hetero association has been obtained from the concentration and solvent dependence of the nuclear Overhauser enhancements (NOE) of solutions of the nucleosides. The enhancement factors of aqueous solutions of dA and I depend on the concentrations of the nucleosides. In solutions containing I the NOE found previously in DMSO and the NOE observed in D2O differ significantly 1. The results obtained can be explained by a change of the average glycosyl torsion angle of approximately 10° to 15° in the two solvents.
Interaction of Actin and Myosin in the Absence and Presence of ATP
Authors: Dancker Peter , Hoffmann Marianne 
Published: August 2018

Abstract
The binding between F-actin and myosin has been studied by analyzing the amount of radio-actively labelled (by means of 14C-NEM) F-actin and myosin in the formed unsoluble actomyosin pellet after centrifugation of the reaction mixture. In the absence of ATP, the amount of actin bound to myosin varies, depending on the amounts of actin and myosin present, between 0.18 mg actin/mg myosin (2 actin units per 1 myosin molecule) and about 2 mg actin/mg myosin (each actin fibril only uncompletely saturated with myosin). In 0.03 ᴍ KCl ATP decreases, if at all, the affinity of actin towards myosin only slightly; but less actin is bound to myosin in the presence of MgATP and in low ionic strength, indicating that myosin is now more densily distributed over fewer actin fibrils leaving the rest of fibrils free. For precipitation of the total amount of myosin (myosin alone is soluble in MgATP) incomplete saturation of myosin with actin suffices; obviously actin promotes filament formation of myosin. The activation of myosin ATPase by actin depends in a similar manner as actin binding does on actin concentration, hence the enzymatic interaction between actin and myosin is accompanied by true actin-myosin binding. An actin-tropomyosin-troponin preparation, whose reduced viscosity is lower than that of F-actin and which consists of about 30% actin, activates myosin ATPase to the same extent as F-actin does. It competes with F-actin for the same binding sites on myosin and can in the presence of MgATP be displaced from myosin by those preparations of F-actin which have a strong tendency to become fully saturated with myosin. The activation of myosin ATPase by actin-tropomyosin-troponin is reduced after tryptic digestion of actin-tropomyosin-troponin, which affects, according to SDS gel electro­ phoresis, mainly two components of troponin with molecular weights of about 32 000 and 25 000, respectively.
Die Struktur von Mimulaxanthin / The Structure of Mimulaxanthin
Authors: Nitsche Helfried 
Published: August 2018

Abstract
Mimulaxanthin, a xanthophyll from the petals of Mimulus guttatus (Monkey flower), has the structure of a 6,7,6′,7′-tetradehydro-5,6,5′,6′-tetrahydro,β,β-carotene-3,5,3′,5′-tetrol. This was con­ firmed by mass, nuclear magnetic resonance (NMR) and infrared (IR) spectra. The pigment yielded a diacetate, diacetate-di (trimethylsilyl)-ether, and a diether with acidified methanol. The free or acetylated pigment was transformed into the diacetylenic xanthophyll alloxanthin (7,8,7′,8′-tetra-dehydro-β,β-carotene-3,3′-diol) or alloxanthin-diacetate with acidic acetone.
Fluorescence Studies on Ferredoxin-NADP Reductase
Authors: Böger Peter , Lien Stephen S. , San Pietro Anthony 
Published: August 2018

Abstract
With highly purified preparations of ferredoxin-NADP reductase (EC 1.6.99.4; also EC 1.6.1.1) from spinach chloroplasts a strong flavin fluorescence was observed (excitation at 450 nm). At pH 7.0, the fluorescence was approximately 40% higher than that of free FAD. Pure reductase from the heterokont alga Bumilleriopsis had only a fluorescence of less than 5% of that of the spinach protein. Essentially the same low fluorescence was found with impure spinach reductase preparations. The low-fluorescent samples of both species exhibited about the same quenching response to salts and buffers which differed from the highly fluorescent spinach flavoprotein preparation. The low fluorescence of the algal protein could be enhanced by NADP, but not by ferredoxin. Maximum fluorescence increase was observed when reductase and NADP were present in a 1:1 molar ratio. Ferredoxin did not counteract the reductase are hereby substantiated.
The Effect of Pattern Movement on the Impulse Activity of the Cervical Connective of Drosophila melanogaster
Authors: Hengstenberg R. 
Published: August 2018

Abstract
Action potentials of some of the 3578 nerve fibres in the cervical connective of Drosophila melanogaster can be recorded with extracellular electrodes. The spike rate increases if moving striped patterns are presented to the compound eyes, especially with horizontal front-to-back movement. The response is small or absent with the reverse (or with vertical) directions of movement. The main properties of this response are described, and briefly discussed.
Measurement of a Steady State Current in the Dark in Photoreceptors of the Barnacle
Authors: Krischer Christof C. , Hupp D. 
Published: August 2018

Abstract
Receptor potentials are measured extracellularly by means of an air gap method along the optic nerve of the median and the lateral photoreceptor of the barnacle. Both photoreceptors have an outward dark current (photoreceptor positive with respect to the nerve) which is diminished ap­proximately 70% during the plateau phase of the receptor potential. Ouabain abolishes dark current and receptor potential in the same proportion. With a Limulus lateral eye preparation a dark cur­rent and light induced current changes were measured which had the same polarity and a similar magnitude as the receptor currents of the barnacle.
Effects of Ultrasonic Irradiation upon Amoeba proteus
Authors: Holmer N. G. , Johnsson A. , Josefsson J.. 
Published: August 2018

Abstract
Amoeba proteus was ultrasonically irradiated, the ultrasonic mean output intensity being about 0.4 W/cm2 at 1 MHz. Contractions of amoebae, rotations and aggregation of intracellular particles and cell membrane damages were observed. At even lower ultrasonic intensities sodium pinocytosis was found to increase after application of ultrasound.
Effect of D2O on the Circadian Rhythm of Petal Movement of Kalanchoe
Authors: Maurer Albrecht , Engelmann Wolfgang 
Published: August 2018

Abstract
D2O lengthens the free running period of the circadian petal movement of isolated Kalanchoe flowers by 1.6% per 10% heavy water. This corresponds to findings reported in the literature for other organisms. 100% D2O administered in the form of 4 hour pulses at various phases of the circadian cycle lead to phase responses zero to maximally 1.5 hour delays. No advancing phase shifts occur. Possible ways in which lengthening of the period occurs are discussed.
Effect of Salts on the Activity and Inhibition of E. coli Membrane ATPase by Ethacrynic Acid and Inhibitors
Authors: Günther Theodor , Pellnitz Wolfgang , Mariß Gert 
Published: August 2018

Abstract
The [Mg, Ca]-ATPase activity of E. coli depends on the anion present and follows the chaotropic sequence: Acetate- > HCO3
- > Cl- > I- > NO3
- > SCN-. There are only small differences between the different alkali chlorides. The [Mg, Ca]-ATPase was inhibited by all these salts when the ratio of Mg or Ca to ATP was 1: 5 at pH 9.1.
At pH 9.1 or 7.5 and a Mg to ATP ratio of 1 some salts activate and others inhibit the enzyme according to their position in the chaotropic sequence. With Ca the ATPase was activated under these conditions only by acetate. The contradictory activation or inhibition by NaCl or KCl reported by various authors are due to differences in the Mg: ATP ratios used. The inhibition of ATPase by ethacrynic acid, NEM, pCMB. DCCD and azide is much greater at pH 9.1 than at pH 7.5 and is drastically affected by NaCl or KCl.
Transforming Activity in Both Complementary Strands of Bacillus subtilis DNA
Authors: Köhnlein Wolfgang 
Published: August 2018

Abstract
A Bacillus subtilis mutant (strain 168 try- thy-) with a thymine-adenine bias in complementary DNA strands was found. After BrU-incorporation into the DNA it was possible to separate physically hybrid DNA-molecules BrU-labeled in different complementary strands using CsCl density gradient centrifugation. These hybrid DNA preparations were used to investigate whether both strands can be informative during transformation. Taking advantage of the selective degradation of BrU-labeled DNA strands by long wavelength UV it was found that the loss of transforming acti vity was the same for both hybrid DNA preparations. Thus indicating that both complementary DNA strands can be genetically active during transformation. These results are supported by trans­ formation experiments with denatured and reannealed DNA-molecules and heteroduplex DNA-molecules.
Isolation of Cyanogen Bromide Cleavage Peptides from Myoglobins
Authors: Marshall Robert C. , Jones, Jr. Warren C. , Vigna Robert A. , Gurd Frank R. N. 
Published: August 2018

Abstract
The chemical cleavage of apomyoglobins by the cyanogen bromide procedure1 has provided frag­ ments suitable for sequence analysis2, 3 and for studies of physical 4-6 and immunochemical pro­ perties 7. Offord 8 has used a peptide obtained from the cyanogen bromide cleavage of ribonuclease in studies aimed at the semi-synthesis of a protein.
The purpose of this report is to present conditions that reliably separate pure peptide fragments produced from the apomyoglobins of several species. A single gel filtration step obviates the need for additional purification2,3,6. The evidence re­ ported here concerns specifically the apoprotein of sperm whale (Physeter catodon) and California sea lion (Zalophus californianus) . The procedure additionally has heen applied9 without modification to the separation of the cyanogen bromide fragments of apomyoglobin from Amazon River dolphin (lnia geoffrensis), Minke whale (Balaenoptera aeutoro- strala), gray whale (Eschrichtius gibbosus), Dali porpoise (Phocoenoides dalli dalli) and the bottlenosed dolphin (Tursiops truncatus). Cyanogen bromide fragments from two of the variant myoglo­bins which occur to a minor extent in the sperm whale were also separated by this method 10.
The Inhibition of Photosynthetic Electron Transport by DBMIB and its Restoration by p-Phenylenediamines; Studied by Means of Prompt and Delayed Chlorophyll Fluorescence of Green Algae
Authors: Bauer Robert , Wijnands Mathijs J. G. 
Published: August 2018

Abstract
The effect of the plastohydroquinone antagonist dibromothym oquinone (DBMIB) on photosynthetic electron transport reactions was studied in the presence and absence of p-phenylene-diamines by means of measurements of prompt and delayed chlorophyll fluorescence induction of the green alga Scenedesm us obliquus.
Prompt and delayed chlorophyll fluorescence induction phenomena are valid indicators for the native presence of and cooperation between the two photosynthetic light reactions. Their kinetics reflect the balancing of electron exchange reactions in the chain of coupled redox-systems between the two photosystems upon sudden illumination.
From distinct alterations of the short-term (sec) light induced changes in the yield of prom pt and delayed chlorophyll fluorescence it is concluded that DBMIB inhibits the photosynthetic electron transport in the chain of redox-systems between the two light reactions. There is evidence to show that upon illumination of DBMIB treated cells only the reduction of primary electron ac­ceptor pools of photosystem II (i. e. Q and PQ) is still possible. After their reduction the further electron transport through photosystem II is blocked.
The addition of p-phenylenediamines to DBM IB-treated cells abolishes the typical DBMIB-affected prom pt and delayed fluorescence inhibition curves and the normal induction curves re­ appear qualitatively in all their important features. From these measurements it is suggested that the redox properties of p-phenylenediamines allow an electron transport bypass of the DBMIB inhibition site which results in a fully restored photosynthetic electron transport from water to NADP.
The Influence of Wingbeat Synchronous Feedback on the Motor Output Systems in Flies
Authors: Heide Gerhard 
Published: August 2018

Abstract
Action potentials have been recorded from fibrillar and from non-fibrillar flight muscles of tethered flying flies (Calliphora erythrocephala and Musca domestica).
Analyses of the spike-trains from the fibrillar muscles reveal a clear preference of the spikes to appear at a special phase with respect to the wingbeat cycle. This holds true even in cases of ex­perimentally changed motor output patterns. There seems to be some kind of wingbeat-synchronous feedback which influences the output system phasically.
Crosscorrelations between spike-trains from the fibrillar muscles on the one hand and the non-fibrillar muscles on the other give evidence that there are strong interactions between the output producing neurons of both systems with at least one inhibitory pathway.
Einfluß von Serum auf die Eliminierung von Phospholipiden aus embryonalen Rattenfibroblasten in Kultur /Influence of Serum on the Release of Phospholipids from Embryonic Rat Cells in Culture
Authors: Ristow Hans-Jiirgen , Pachowsky Heinz , Frank Werner 
Published: August 2018

Abstract
The phospholipids of embryonic rat fibroblasts in tissue culture have been labelled with [3H] (myo) inositol, [3H] choline, [3H] glycerol and inorganic 32P , respectively. After 24 hours in serum-free medium the cells have been triggered by fetal calf serum or by a mixture of the growth-stimulating serum proteins S1 and S2, and the phospholipids were examined.
1. Up to 15 - 20 percent of total radioactivity are eliminated from the phospholipid fraction during 30 min after stimulation, when the cells have been prelabelled with [3H ]inositol; within 2 hours, however, the original value is restored. When the cells are prelabelled with 32P, the radio­ activity also decreases, but in contrast to the experiments with [3H] inositol it remains low. From this result one must conclude that part of the PI in the membranes is broken down after stimula­ tion, and that the inosit moity is reutilized for newly synthesized PI. After stimulation, a small amount of labelled PI is also found in the culture medium .
2. The elimination of radioactivity does not exclusively take place in phase. It can also be demonstrated with cells in S after removal of serum for one hour and readdition.
3. The loss of radioactivity cannot be demonstrated when the cells are triggered by dialysed fetal calf serum or by the serum factors S1 and S2. Examination of the dialysate revealed phosphatidvlinositol as compound which necessarily must be present for the elimination process after stimulation. This elimination process is also demonstrable if the biosynthesis of PI is blocked by gamma-or delta-hexachlorocyclohexane, whereas the beta derivative is completely ineffective.
Eine quantitative Bestimmungsmethode des Uracilgehaltes biologischen Materials im Nanogramm-Bereich mit Hilfe der Hochdruck-Flüssigchromatografie / A Method for the Quantitative Estimation of Uracil Content in Biological Materials in the Nanogramme-Range Using High-Pressure Liquid Chromatography
Authors: Breter Hans-Joachim , Schnaus Marianne , Müller Werner E. G. , Zahn Rudolf K. 
Published: August 2018

Abstract
A method is described for the estimation of the uracil content in biological materials by means of high-pressure liquid chromatography. Hydrolysis of the tissues and total liberation of RNA bases are carried out in 70% perchloric acid. Less than 1 mg of the materials are needed for analysis. A pre-purification of the hydrolyzates is carried out by anion-exchange chromatography. Recoveries are estimated by isotope dilution analysis with [2-14C] labelled uracil.
The method is highly sensitive - about 6000 pmol of uracil content can at least be estimated quantitatively - and analysis time is short. In routine analysis a single sample needs 4 hours to be completed. When preparing several samples at a time an analysis is completed every 45min.
DNA, a Component of the Outer Membrane of Ehrlich Ascites Tumor Cells and its Role in RNA Uptake by These Cells
Authors: Schell P. L. , Müller W. H. 
Published: August 2018

Abstract
DNase treatment of Ehrlich ascites tumor cells releases DNA fragments from the membrane surface. This increases the capacity of the cells for homoribopolynucleotide uptake.
Another portion of membrane DNA is embedded in protein structures and is not accessible for DNase. This DNA does not hinder ribopolynucleotide uptake unless it is unwrapped by a sub­ equent pronase treatment of the cells. We interprete these findings to be the consequence of alterations of the net negative charge brought about by the removal and reestablishment of "open" surface DNA.
Mass Spectral Study of D-Sesamin from Phyllarthron comorense
Authors: Joshi Krishna C. , Bansal R. K. , Singh Pahup 
Published: August 2018

Abstract
D-Sesamin, Phyllarthron comorense, Mass Spectrum The petroleum ether extract of the heartwood of Phyllarthron comorense DC affords D-sesamin along with paulownin, lapachol, dehydrotectol, dehydro-a-lapachone, /Mapachone, tectol and /5-sitosterol1. We have earlier communicated the mass spectrometric studies of dehydro-a-lapachone2 and paulownin3. The present work deals with the formulation of pos­ sible fragmentation schemes in the case of D-sesamin. This compound is a member of 3,7-dioxabicyclo-Table I. Mass spectral data of D-sesamin a. S. No. m\e Ion composition Relative intensities
Chemical Constituents of Corchorus capsuJaris and C. olitorius (Jute Plant), III. Structure of Corosin
Authors: Manzoor-i-Khuda M. , Habermehl Gerhard 
Published: August 2018

Corosin (8; R = R1 = H) has been reisolated through a modified procedure, as its acetate (8; R=H, R1 = Ac), in an overall yield of 0.2% from jute roots.
On pyrolysis in vacuo, corosin gave pyro corosin (1a; R1 = OH, R2= COOH, R3 = R5 = H, R4 = R6 = Me), shown to have a 12:18 (17) di-ene formed by elimination of the 19-OH and the angular C-28 carboxyl in the molecule. On rearrangement with concentrated sulphuric acid in acetic acid, corosin acetate gave corosin anhydro lactone acetate (7; R1 = Ac, R = H), having a 13(18) double bond and a lactone bridge between the 28-carboxyl and the 20-carbon atom. Corosin acetate ester (8; R = Me, R 1 = Ac), on treatment with sulphuric-acetic acid reagent, gave as the main product anhydro corosin acetate ester (7; R = Me, R1= A c), with a 12:18(19)-diene. The structure of corosin is proposed to be urs-12-ene-2α, 3β, 19α-trihydroxy-24, 28-dioic acid (8; R = R1= H).
Circadiane Rhythm of Cell Proliferation in Rat Liver: Synchronization by Feeding Habits
Authors: Schulte-Hermann Rolf , Landgraf Hanna 
Published: August 2018

Abstract
A diurnal rhythm of cell proliferation exists in the liver of young rodents and in the growing liver of rats treated with α-hexachlorocyclohexane (α-HCH). The timing of the rhythm is dependent on the time of feeding but independent from the lighting regimen. This suggests that under natural circumstances the light-dark rhythm synchronizes the rhythm of hepatocyte proliferation by con­ trolling the animals' feeding habits.