bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulatory Properties of Glutamine Synthetase from the Nitrogen-Fixing Phototrophic Bacterium Rhodopseudomonas palustris
Authors: Alef Kassem , Zumft Walter G. 
Published: August 2018

Abstract
Rhodopseudomonas palustris, Glutamine Synthetase Regulation, Adenylylation Glutamine synthetase from Rhodopseudomonas palustris is regulated via an adenylylation/deadenylylation mechanism. The enzyme purified from ammonia-grown cells, released AMP upon treatment with phosphodiesterase, along with drastic changes in its pH and metal dependency. Kinetic parameters for enzyme-substrate interaction were also dependent on the adenylylation state of the enzyme, as was the influence of several nitrogenous feedback inhibitors on the catalytic activity. The adenylylation state of the enzyme was modified in vivo by the availability of ammonia.
Thalidomide-Like Malformations Caused by a Tween Surfactant in Mice
Authors: Kocher-Becker Ursula , Kocher Walter , Ockenfels Heinrich 
Published: August 2018

Abstract
The nonionic surfactant Tween 20 was applied intra-peritoneally to NMRI and Swiss mice on day 9 of gestation. It caused embryonic death and malformations of the verte­ brae, ribs and, in lower frequency, of the limbs.
Temperaturabhängiger Farbwechsel bei Larven der grünen Huschspinne Micromata rosea (Sparassidae) / Temperature-Dependent Colour Change in Larvae of the Green Spider Micromata rosea (Sparassidae)
Authors: Holl Arthur 
Published: August 2018

Abstract
In the green coloured larvae of Micromata rosea but not in adults temperature raise above 29 °C causes immediate colour change: green to bluish-green. Colour change is reversible by temperature decline below 29 °C. Qualitative analysis of the yolk pigment reveals the same biliverdin conjugates (micromatabilin) as previously identified for adult spiders. The bluish-green colour (above 29 °C) re­sults from an absorption band (675-680 nm, water phase, purified solution) modified to that of the green solution (below 29 °C). Presumably, the thermodependent, rever­sible colour change is due to a special yolk protein bond to the micromatabilin chromophor.
Bleaching Activity of New 2-Phenylpyridazinones: Structure-Activity Relationship
Authors: Sandmann Gerhard , Böger Peter 
Published: August 2018

Abstract
New 2-phenylpyridazinones, analogs of 4-chloro-5-methylamino-2-phenylpyridazin-3(2H)ones, were assayed for their phytotoxic activity to interfere with plant pigment formation. Six derivatives with - SCF3, - OCF2CHFCF3, - OCHF2, - CN, or - Br in meta position of the phenyl ring exhibited similar or better bleaching activity than the m-CF3 analog (norflurazon). The activity is predominantly determined by positive σ values and by lipophilicity of the substituent. On the basis of 11 analogs, a quantitative structure-activity relationship by a Hansch equation was accomplished with σm and the lipophilicity parameter π as variables.
The Intracellular Distribution of Enzymes of the Glycerol Cycle in the Unicellular Alga Dunaliella parva
Authors: Gimmler H. , Lotter G. 
Published: August 2018

Abstract
The intracellular distribution of the enzymes of the glycerol cycle in the unicellular alga Dunaliella parva was investigated using the technique of differential extraction by the polycation DEAE-dextran.
Results suggest a cytoplasmic localization of the DHA reductase, but a chloroplastic localization of the glycerol-3-phosphate dehydrogenase and phosphatase.
Osmoregulation in Dunaliella. Intracellular Distribution of Enzymes of Glycerol Metabolism
Authors: Brown A. D. , Lilley R. McC. , Marengo Thérèse 
Published: August 2018

Abstract
Dunaliella tertiolecta was disrupted mechanically and resolved by centrifugation into chloro­plast- and cytosol-enriched fractions. Intact chloroplasts could not be isolated because peripheral extensions of the single large chloroplast reached almost to the flagellar pole of the cell. The chloroplast envelope was closely appressed to the plasmalemma and, because of this and its dimensions, was vulnerable to mechanical damage to the cell.
Distribution of enzymes of the glycerol cycle between the two fractions was compared with that of two marker enzymes, phosphoenolpyruvate carboxylase (cytosol) and ribulose bisphosphate carboxylase (chloroplast). The two reversible steps of the cycle were found to be spatially separated; glycerol-3-phosphate dehydrogenase (NAD-specific) was located in the chloroplast whereas glycerol dehydrogenase (NADP-specific) was located in the cytosol. The distribution of the two irreversible enzymes, glycerol phosphate phosphatase and dihydroxyacetone kinase is uncertain. These enzymes might occur about equally in both major compartments (cytoplasm and chloroplast) or be mitochondrial or they might be loosely associated with a membrane system. Implications of these results for regulation of the glycerol cycle are discussed.
Struktur-Wirkungsbeziehungen von Analogen und Homologen von Blepharisma, dem niedermolekularem Konjugationshormon von Blepharisma japonicum / Structure-Activity-Relation of Analogues and Homologues of Blepharismone, the Low-Molecular Conjugation Hormone of Blepharisma japonicum
Authors: Entzeroth Michael , Jaenicke Lothar 
Published: August 2018

Abstract
Some functional derivatives of blepharismone, the low-molecular conjugation hormone of Blepharisma japonicum, were synthesised and tested for their biological activity. The lipophilicity constant of the substituent in 5-position of the aromatic system directly correlates with the conjugation-inducing effect of this substance. Any change in the N-formyl-position leads to compounds less active than blepharismone, non-active or even inhibitory. Blepharismone-related kynurenine derivatives are inhibitors of the gamone activity depending on structural relationship.
X-Ray Studies on Phospholipid Bilayers. II. Polymorphic Forms of Dipalmitoyl Phosphatidylethanolamine
Authors: Suwalsky M. , Knight E. 
Published: August 2018

Abstract
Oriented films and powder samples of the phospholipid ʟ-α-dipalmitoyl phosphatidylethanol­ amine (DPPE) were studied by X-ray fiber diffraction techniques. The specimens were photographed under a complete range of hydration at room temperature. Two polymorphic forms were found. One of them was present in oriented films. It showed a close packing of DPPE molecules lying parallel to the normal to the bilayer plane. The other form, observed in the powder samples, had the molecules tilted by about 25°. Both forms were characterized by their unit cell dimensions, space groups, molecular conformations and packing arrangements.
Exogenous and Endogenous Control of Swimming Activity in Astyanax mexicanus (Characidae, Pisces) by Direct Light Response and by a Circadian Oscillator I. Analyses of the Time-Control Systems of an Epigean River Population
Authors: Erckens Wilhelmine , Martin Wolfgang 
Published: August 2018

Abstract
1. The swimming activity of 6 specimens of an Astyanax mexicanus' river population was tested with regard to its time control under various light-dark(LD)cycles and under constant conditions.
2. Activity is classified into three different forms according to the special experimental arrangement: surface activity, bottom activity and the sum of both (total activity).
3. All applied LD-cycles act as socalled forcing signals (Zeitgeber) and entrain the activity.
4. The maximum values of surface activity correspond to the dark phases of a LD-cycle, those of bottom activity to the light phases. This inversity causes a less strong entrainment of the total activity up to a loss of a significant oscillation in extreme cases.
5. This inverse pattern is kept the more stronger the more the period length of a LD deviates from 24 h. In the range of resonance about 24 h there is a greater flexibility with regard to the phase relation of the maximum values.
6. Activity reacts very sensitive to the differential parameter of the forcing signal. Therefore, no phaseangle difference occurs between forcing and forced signal. Moreover, the system needs no swing-in time to become entrained when starting a LD.
7. After transition from LD to DD (= constant darkness) the forced signal does not die away immediately, but damps out within one or a few cycles with decreasing amplitude and unchanged frequency.
8. In nearly all applied LDs a non-synchronized circadian rhythm can be observed in addition to the entrained frequency, which is dominant.
9. Also, in DD a freerunning circadian rhythm is detectable.
10. We suggest the model that first a passive system with a nearly unlimited range of entrainment controls activity. In contrary to extremely passive systems, it is able to oscillate. Moreover, it acts like a linear system with respect to frequency transfer: In the tested cases, output and input frequency are equal. In addition, activity is under control of an endogenous circadian oscillator. Its effects are overlapped under forcing conditions, but they become obvious under constant conditions. Furthermore, nonstationary processes are features of this circadian rhythm. The proper­ ties of a passive and a circadian system alone do not explain the flexible patterns in the range of resonance. Therefore, a time-dependent controller is demanded to control the phase relation of the maxima.
Exogenous and Endogenous Control of Swimming Activity in Astyanax mexicanus (Characidae, Pisces) by Direct Light Response and by a Circadian Oscillator II. Features of Time-Controlled Behaviour of a Cave Population and their Comparison to a Epigean Ancestral Form
Authors: Erckens Wilhelmine , Martin Wolfgang 
Published: August 2018

Abstract
1. The swimming activity of 6 specimens of the Pachon cave form of Astyanax mexicanus was tested with regard to its time control under various light-dark(LD)cycles and constant conditions, and it is compared to that of a river form.
2. In general, activity is entrainable by all applied LDs, but even if the amplitude of a forcing signal increases the signal energies are lower than in the river fish.
3. In case of entrainment the maximum values of surface activity correspond to the dark phases, those of bottom activity to the light phases of a LD. Flexible patterns -as often observed in the river form in the range of resonance about 24 h - are very seldom. Furthermore, disturbances of­ ten occur in the entrainment of one activity form, or one form runs arrhythmic while the other is still entrained.
4. The activity answers to changing environmental conditions are not as uniformly quick as in the river fish. But the system hardly needs a swing-in time to become entrained when a LD starts.
5. After transition from LD to DD (= constant darkness) the entrained rhythms disappear immediately.
6. In no LD with a period length differing from 24 h a circadian rhythm can be observed in addition to the entrained frequency.
7. These results show that the passive system of the river form has developped into an extremely passive one being unable to oscillate and thus has become simplified during regressive evolution. Concerning the circadian oscillator of the epigean ancestor, it was also subjected to regression, but it has not been completely lost. After a LD with a period length about 24 h the circadian oscillator is able to act as a stable system, clearly shown by the freerunning circadian rhythms of surface activity. But out of this range the oscillator is unable to control activity. In DD after all other LDs activity patterns are arrhythmic.
Monoterpenes from the True Bug Harpocera thoracica (Hemiptera)
Authors: Hanssen Hans-Peter , Jacob Jürgen 
Published: August 2018

Abstract
From the “head space” * of Harpocera thoracica (Miridae; Hemiptera) six monoterpenes have been isolated and identified by GLC and MS data in comparison with authentic reference substances. Predominant component was geranyl acetate. Apart from this, the alcohols geraniol and nerol, neryl acetate, and the corresponding aldehydes geranial and neral could be identified.
Small- and Large-Angle X-Ray Scattering Studies of Counter Ion Influence on tRNA Conformation*
Authors: Wilhelm Peter , Pilz Ingrid , Degovics Gábor , Haar Friedrich von der 
Published: August 2018

Abstract
The determination of cross sectional radii of gyration by small-angle X-ray scattering and comparison of large-angle scattering curves were used to study conformational changes of tRNAs depending on the concentration of mono-and divalent counter ions.
Structure Investigations of Agonists of the Natural Neurotransmitter Acetylcholine II [1]. X-ray Structure Analysis of Trimethyl(4-oxopentyl)ammonium-chloride
Authors: Gieren Gieren , Kokkinidis Michail 
Published: August 2018

Abstract
The crystal structure of Trimethyl(4-oxopentyl)ammonium-chloride ([(CH3)3N+-(CH2)3COCH3]Cl-) (1) was determined by an X-ray structure analysis. 1 crystallizes in the orthorhombic space group P212121 with a = 10.440 (3), b = 14.600 (9), c = 6.804 (9) Å and with four formula units per unit cell. The structure was solved by a Patterson and a successive Fourier synthesis. The least squares refinement yielded an R-value of 0.064 for 1077 observed reflections. The cation of 1 is derived from acetylcholine by replacement of the ester oxygen with a CH2 group. It shows a potent nicotinic activity and a significant difference in conformation as compared with acetylcholine. In the crystal structure the anions are oriented stereospecifically with respect to the tetrahedron of the quaternary ammonium group. The geometry of two triangles formed by the quaternary nitrogen atom, the oxygen atom of the carbonyl group, and by either of the two anions nearest to the quaternary ammonium group is characteristic for the nicotinic activity of 1.
Bile Salt Delipidation, Residual Phospholipids and Reactivation of the Ca2+-ATPase from Sarcoplasmic Reticulum
Authors: Swoboda Gertrude , Hasselbach Wilhelm 
Published: August 2018

Abstract
1. Delipidation of the Ca2+-ATPase of sarcoplasmic reticulum membranes by gel chromatography employing ionic detergents (cholate, deoxycholate and mixtures of both) in the presence of glycerol has been studied with respect to residual phospholipids and ATPase activities.
2. The extent of delipidation depends on the detergent chosen and on the ionic strength of the elution buffer. Increasing ionic strength favours a more effective removal of phospholipids, down to about 1 phospholipid molecule per ATPase molecule.
3. The residual ATPase activities of the delipidated preparations are negligibly low. Extensive restoration of the Ca2+-dependent ATPase activity has been achieved by oleic acid, a lysolecithin (myristoylglycerophosphocholine) and a lecithin (dimyristoylglycerophosphocholine). The per­ centage of reactivation by oleate depends linearly on the amount of residual phospholipids and on the detergent employed.
4. After gel filtration through an Ultrogel or Sepharose column containing 1% cholate in the elution buffer the delipidated ATPase is eluted as a reactivatable high molecular aggregate, whereas 1% deoxycholate favours the formation of completely lipid-free monomeric units which cannot be reactivated, however. A high molecular aggregate is also formed in deoxycholate, the ratio of monomer to polymer depending on the solubilizing and elution conditions.
5. The residual lipids are always composed of a mixture of all different lipid classes present in the native sarcoplasmic vesicles, even at high degrees of delipidation. Specific changes with varying extent of delipidation were not detected.
Screening for Highly Active Plasmid Promoters via Fusion to β-Galactosidase Gene
Authors: Rosner Arie , Gorecki Marian , Aviv Haim 
Published: August 2018

Abstract
A plasmid containing promoter-deleted inactive β-galactosidase gene [1] was used to select promoters of the pEP121 plasmid [2]. Colonies of cells harboring reactivated β-galactosidase gene were identified by their red color on McConkey plates. The quantitative amounts of β-galactosidase produced in each clone were estimated by assaying enzyme activity and by measuring the specific β-galactosidase protein following fractionation of total cells′ proteins on polyacrylamide gel. A wide range of enzyme activities was observed. The most active promoter isolated was shown to promote β-galactosidase production more efficiently, compared with the original β-galactosidase promoter, amounting to 20% of all cell proteins. Such highly active promoters may be utilized in the future, to promote expression of cloned genes in bacteria.
Functional Significance of Quaternary Organization of the Sarcoplasmic Reticulum Ca2+-ATPase
Authors: Møller Jesper V. , Mahrous Talaat S. , Andersen Jens P. , Maire Marc le 
Published: August 2018

Abstract
There is both structural and functional evidence for protein-protein interaction between Ca2+-ATPase polypeptide chains in the sarcoplasmic reticulum membrane. Studies on detergent solubilized ATPase indicate that the monomeric form is capable of performing a normal cycle of ATP hydrolysis, but some of the modulatory effects of the substrates disappear after detergent solubilization. However, the necessity of protein-protein interactions for the Ca2+ transport function remains unclarified. A new approach is described, employing ATPase reconstituted with a large excess of phospholipid, which may help to resolve this question.
ESR Studies on Platinum Uracil Blue
Authors: Neubacher Harald , Seul Michael , Lohmann Wolfgang 
Published: August 2018

Abstract
ESR spectra of platinum uracil “blue” are discussed. Two main types o f paramagnetic species have been found, one of which can be explained by assuming an unpaired electron spin delocalized over dz²-orbitals of two equivalent Pt centers, the other one is attributed to a more localized d7 Pt(III) center. In both cases the hyperfine structure suggests an additional smaller probability density of the unpaired electron at one adjacent platinum center. The smallest possible oligomers to realize this facts are tetramers in the first case and dimers in the latter one.
Formation of Flavonol 3-O-Diglycosides and Flavonol 3-O-Triglycosides by Enzyme Extracts from Anthers of Tulipa cv. Apeldoorn / Characterization and Activity of Three Different O -Glycosyltransferases during Anther Development
Authors: Kleinehollenhorst G. , Behrens H. , Pegels G. , Srunk N. , Wiermann R. 
Published: August 2018

Abstract
Three distinct glycosyltransferases have been isolated and partially purified from anthers of Tulipa cv. Apeldoorn. The following designations are proposed; UDP-glucose: flavonol 3-O-glucosyltransferase (GT-I), UDP-rhamnose: flavonol 3-O-glucoside rhamnosyltransferase (GT-II) and UDP-xylose: flavonol 3-glycoside xylosyltransferase (GT-III). The three enzymes exhibited an identical pH optimum within the range of 8.5 -9.0. The estimated molecular weight of GT-I and GT-II was about 40 000, GT-III showed a molecular weight of 30 000. GT-III required ions like NH4
+or Ca2+ whereas these ions have almost no influence on GT-I and GT-II activity. The enzymes have a slight requirement for SH-reagents, particularly DTE. As opposed to GT-II activity of GT-I and GT-III is significantly influenced by SH reagents and PCMB. Sucrose enhanced GT-III activity but only slightly GT-I activity, GT-II activity is not influenced.
Flavonol aglycones can function as glycosyl acceptor for the GT-I, whereas flavonol 3-O-glycosides, luteolin, dihydroquercetin, naringenin, cyanidin, p-coumaric acid and some other phenols were inactive as acceptor. The best acceptors were isorhamnetin and quercetin (Km: 0.9 × 10-6 ᴍ). GT-II did not accept aglycones as substrates. For this enzyme flavonol 3-O-glucosides were the most attractive substrates. GT-III did not have any affinity towards aglycones, too. This enzyme exhibited a high specificity for flavonol 3-O-glucosides as well as flavonol 3-O-galactosides. Both enzymes, the GT-II and GT-III, were able to glycosylate flavonol 3-O-diglycosides forming triglycosides. UDP-glucose (Km = 1.0 × 10-4 ᴍ), UDP-rhamnose and UDP-xylose where shown to be the best glycosyl donors for GT-I, GT-II or GT-III respectively. The glycosyl transfer catalysed by the GT-I was shown to be a freely reversible reaction.
In the whole anthers, highest specific activities of GT-I and GT-II were found during late stages of anther development. Similar results were obtained using the contents of anthers or the tapetum fraction. In contrary, high GT-III activity can be detected already in young stages of anther devel­opment. The highest activities of the three glycosyltransferases were found in the tapetum fraction, whereas the pollen fraction exhibited only poor activities.
Effects of Substituted 2-Phenylamino-1,4,5,6-tetrahydropyrimidines on ATP Formation in Isolated Spinach Chloroplasts
Authors: Berg Gerard van den , Brandse Marjo , Tipker Jacobus 
Published: August 2018

Abstract
The effects of a series of 2-arylamino-1,4,5,6-tetrahydropyrimidines on photosynthesis in spinach chloroplast were studied. The compounds proved to be uncouplers of photophosphorylation, while inhibition of electron transport occurred at higher concentrations. These effects were rather irreversible and the activity increased with lipophilicity. Inhibition of electron transport could not be reversed by trypsin treatmeni. Loss of membrane integrity might be the underlying mechanism of these effects.
Electromechanical Coupling III. Estimation of the Ca Storage Capacity of the SR by Analysing the Time Course of Caffeine- Induced Tension Transients of Skinned Muscle Fibres
Authors: Thieleczek Rolf 
Published: August 2018

Abstract
The Ca uptake of the SR of a skinned fibre, which was studied with an indirect method, shows a biphasic time course. A total Ca concentration between 8 and 23 mᴍ was accumulated in the SR by an initial fast process (τ ≈ 4.7 s). This Ca-uptake activity of the SR is high enough to bring about relaxation o f twitch contraction in vivo. The magnitude of a subsequent slow process (τ ≈ 103s) indicates that the total Ca storage capacity of the SR of skeletal muscle is in the order of 60 - 75 mᴍ.
Intracellular Membranes as Boundaries for Ionic Distribution. In Situ Elemental Distribution in Guinea Pig Heart Muscle in Different Defined Electro-Mechanical Coupling States
Authors: Wendt-Gallitelli M. F. , Jacob R. , Wolburg H. 
Published: August 2018

Abstract
Using x-ray microanalysis and cryoultramicrotomy, calcium and other diffusible elements were localized in heart muscle strips which had been shock frozen under different, defined conditions of electromechanical coupling. Guinea pig papillary muscles were shock frozen: 1) 1 1/2 seconds after paired stimulation, 2) 5 minutes after rest in normal bath medium and 3) 5 minutes after rest in bath medium to which noradrenaline was added. In 1) high calcium concentrations of 11.5 mmol/kg d.w. were regularly detected in sites at the level of Z-lines, which probably corre- spond to the Z rete of SR. In 2) in which the mechanogram of the first contraction after rest normally showed a small and retarded peak, the cell stores seemed to be nearly empty, with exception of a few regions between the mitochondria which revealed calcium accumulations of 77 mmol/kg d.w. These regions included JSR and/or T-tubuli. In 3) in which the mechanogram of the first contraction after rest normally showed a retarded peak with high tension, calcium was found in several cell structures. The highest amount, 25 mmol/kg d.w., was detected over the cell membrane. Measurable amounts were also detected over Z-lines and sarcomeres.
In the present experiments, the respective rate of rise of tension, and time to peak tension, were extremely different. Possible correlations between different contraction patterns and different calcium stores involved in the various experiments have been discussed.