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1996[X]
1Author    W. D. Rab ErRequires cookie*
 Title    STERIMOL and Its Role in Drug Research  
 Abstract    From the early beginnings of research in syn­ thetic drugs, researchers w ere interested to know the effects of chem ical structure on the p h arm aco ­ logical effects. A s the first system atic studies, the w ork of M eyer (1899) and O verto n (1901) on the narcotic effects of a series of chem icals is re ­ garded, which resulted in their lipoid th eo ry (see: Lipnick, 1986, 1989). A m ong various pro ced u res to calculate the relationship betw een chem ical structure and biological activity, ab b rev iated as Q S A R , the 30 years old H ansch-Fujita approach has been m ost widely and effectively used up to now, in m edicinal chem istry as well as in the field of agrochem icals. In the m eantim e, m any concep­ tual supplem entations and im provem ents as well as m athem atical refinem ents have b een carried out, the m ost im p o rtan t one its extension to three dim ensions. The original form of the H ansch-Fujita equation (H ansch and F ujita, 1964) read 1/logC -a-Ji + b-Ji2 + c -o + d 
  Reference    Z. Naturforsch. 51c, 1—7 (1996); received Septem ber 9/October 27 1995 
  Published    1996 
  Keywords    O SA R, STERIM OL Parameters, Regression Equations, Potosystem II Inhibitors, Herbicidal Activity 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0001.pdf 
 Identifier    ZNC-1996-51c-0001 
 Volume    51 
2Author    E. Ck, H. Ard, W. Ollenw Eber, K. Arin, M. Anna, JamesN R Oitm AnhRequires cookie*
 Title    C-Methyl Flavones from the Leaf Wax of Leptospermum laevigatum (Myrtaceae)  
 Abstract    Leptosperm um laevigatum, Myrtaceae, Leaf Wax, Flavonoid Aglycones, C-M ethyl Flavones Flavonoid aglycones were detected as minor constituents o f the leaf wax o f the Myrtaceae Leptosperm um laevigatum. They belong to the rarely encountered C-methyl flavonoids. One of them is a new natural product, 5-hydroxy-3,7,3',4'-tetramethoxy-6-C-methyl flavone. 
  Reference    Z. Naturforsch. 51c, 8 (1996); received November 10/D ecem ber 11 1995 
  Published    1996 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0008.pdf 
 Identifier    ZNC-1996-51c-0008 
 Volume    51 
3Author    M.C M Arcucci, F. A. De, C. Am Argo, C.M A LopesRequires cookie*
 Title    Identification of Amino Acids in Brazilian Propolis  
 Abstract    A m ino acids o f propolis samples from different origins were analysed and quantified. Seven of them presented almost the same percentage in all samples, indicating that bees may have obtained amino acids from three sources: plants, pollen contamination and from their own metabolism. The regeneration properties of propolis in relation to the presence of som e amino acids are discussed. 
  Reference    Z. Naturforsch. 51c, 11 (1996); received March 27/O ctober 12 1995 
  Published    1996 
  Keywords    Propolis, A m ino Acids, Pollen, Plant Sources, Regenerative Properties 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0011.pdf 
 Identifier    ZNC-1996-51c-0011 
 Volume    51 
4Author    A. Kihiro Tai3, E. Ri, O. Hsaw Ab, K. Azuyoshi, K. Aw Azub, A. Kio, K. Obayashi3Requires cookie*
 Title    A Minimum Essential Structure of LN-3 Elicitor Activity in Bean Cotyledons  
 Abstract    A great deal of an elicitor-active oligosaccharide (1.47 g) was obtained from 40 g of poly­ saccharide laminaran with the guidance of elicitor activity in the bean cotyledon assay. Physicochemical means suggested that the oligosaccharide was a ß-1,3-and ß-l,6-linked tri­ glucoside. This was a partial structure of LN-3, having elicitor activity to alfalfa and bean. The triglucoside exhibited a specific elicitor activity to bean, not to alfalfa and pea. The highly digested hydrolysate containing monom er and dimers as major components did not show elicitor activity in the bean cotyledon assay. The structural feature was essential for elicitation of phytoalexin accumulation in bean cotyledons. These results suggested that this triglucoside had a specific elicitor activity and a minimum elicitor-active entity to bean cotyledons. 
  Reference    Z. Naturforsch. 51c, 15 (1996); received October 27/Novem ber 21 1995 
  Published    1996 
  Keywords    Elicitor, Phytoalexin Accumulation, Bean, Phaseolus vulgaris L, Triglucoside 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0015.pdf 
 Identifier    ZNC-1996-51c-0015 
 Volume    51 
5Author    Z. NaturforschRequires cookie*
 Title    The Oxygen Sensitivity of Nitrogenase in R hodobacter capsulatus: Repression and Inactivation  
 Abstract    G esine K lein11, A n d reas Jahna, A strid S te in d o rf1, W erner K lipph, Jürgen O elzea In chemostat cultures of R hodobacter capsulatus, growing aerobically in darkness, in situ nitrogen fixation occurred at significantly lower oxygen concentrations than the acetylene reduction activity of nitrogenase, as determined with samples from the culture under opti­ mum assay conditions. In contrast to nitrogenase of cultures growing diazotrophically at low oxygen, nitrogenase present in inactive form at the higher oxygen concentrations could not be activated to fix nitrogen by increasing i.) the energy supply by illuminating the cultures, ii.) the supply of cells with electron donor and iii.) cellular respiration. These results suggest that oxygen controls cellular nitrogen fixation directly rather than indirectly by interfering with the general metabolism. On this basis, the sensitivity toward oxygen of n if gene expres­ sion as well as of nitrogenase polypeptide accumulation was studied. The nifH promoter was active up to about 40% air saturation, exhibiting a biphasic sensitivity to oxygen, i.e. steep decreases in activity between 1 to 2% and between 10 to about 20% air saturation. A similar behaviour was observed with respect to cellular levels o f both polypeptides of component 1 (R c l) of nitrogenase, which were accumulated up to about 20% air saturation. Component 2 (Rc2) was less oxygen-sensitive than R c l, its steady state level reached a maximum at 2% air saturation. A sudden increase in the ambient oxygen concentration, i. e. oxygen stress, revealed that, in vivo, nitrogenase was fairly stable against oxygen damage. Modification of Rc2 by ADP-ribosylation occurred under ammonium shock conditions, regardless of whether the cells fixed nitrogen or not. But it was not observed with cultures growing aerobically in the dark at steady state or under oxygen stress. Results obtained with mutant W107I of R. capsulatus lacking the modifying/demodifying enzymes supported the conclusion that modifi­ cation of Rc2 was not required for the inactivation of nitrogenase by oxygen. 
  Reference    Z. Naturforsch. 51c, 20—2 (1996); received October 30 1995 
  Published    1996 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0020.pdf 
 Identifier    ZNC-1996-51c-0020 
 Volume    51 
6Author    K. Erstin Steinert, SusanneB. Ickel-S, AndkötterRequires cookie*
 Title    Isolation, Characterization, and Substrate Specificity of the Plasma Membrane ATPase of the Halophilic Archaeon H aloferax volcanii  
 Abstract    Isolated membranes of the moderate halophilic bacterium Haloferax volcanii are able to hydrolyze ATP via an ATPase, which needs the presence of Mg2+ or Mn2+, high concentra­ tions of NaCl, a pH value of 9, and high temperatures with an optimum at 60 °C. We have not found any phosphatase activity in the preparations. We developed a purification method for the isolated enzyme with an enrichment factor o f 90. SDS-gel electrophoresis of the partially purified enzyme of Haloferax volcanii showed putative ATPase subunits of 63, 51, 37, and 12 kDa. N-ethylmaleimide (NEM) a specific inhibitor for V-ATPases, which alkylates cysteines, inhibited the enzyme slightly. Binding of tritiated NEM to the isolated ATPase fractions resulted in labelling of the 63 and 51 kDa peptides. Using PCR with degenerate oligonucleotides, we could clone and sequence a gene cluster encoding the Aj part o f the halophilic ATPase. The described genes are organized in an operon in the order D. C, E, B, A , named alphabetically according to their decreasing size. The deduced products o f 64.5, 52, 38.7, 22, and 11.6 kDa confirm the results of the partial purification o f the ATPase. Biochemical characterization of the Haloferax volcanii ATPase gave the following results: In presence of Mn2+ higher rates of ATP hydrolysis could be observed than in presence of Mg2+, but free manganese ions inhibited the enzyme activity of the ATPase. Calculation of the true concentrations of the complex between ATP and the respective divalent metal ion led to determination of M ichaelis-Menten constants for ATP in the hydrolysis direction of 1 m M in presence of MgCl2 and 0.24 m M in presence of MnCl2. Sodium chloride concentrations in the molar range induce changes in K M by a factor of about 10. The enzyme is specific for ATP; other nucleotides including GTP and A D P are competitive inhibitors o f ATP hy­ drolysis. 
  Reference    Z. Naturforsch. 51c, 29 (1996); received June 26/Novem ber 11 1995 
  Published    1996 
  Keywords    Archaeon, Haloferax volcanii, Plasma Membrane ATPase, Subunits, ATP-Hydrolysis 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0029.pdf 
 Identifier    ZNC-1996-51c-0029 
 Volume    51 
7Author    ShigetohM. Iyachi11, JoachimB. Ürger, K. Iriakos, K. Otzabasisb, JensT. Hielm Annc, H. O. Rst SengerRequires cookie*
 Title    Photosynthetic Characteristics of Three Strains of Cyanobacteria Grown under Low-or High-C02 Conditions  
 Abstract    Quantum requirements of photosynthetic oxygen evolution at 679 nm, fluorescence em is­ sion spectra at liquid nitrogen temperature (77 K) and fluorescence induction kinetics in the presence of DCM U, were measured in the cyanobacteria Anabaena variabilis M3, Anabaena variabilis ATCC 29413 and A nacystis nidulans R2, each grown under low-or high-C02 condi­ tions. L o w -C 0 2 grown cells o f the cyanobacteria showed a higher quantum requirement of photosynthetic oxygen evolution and a higher ratio o f F7U)_740 to F680_700 fluorescence and a lower variable fluorescence in the presence of D CM U than high-C02 grown cells. These findings indicate a change in excitation energy distribution in favour of photosystem I. The result might be an enhancement in ATP formation caused by cyclic electron flow which in turn provokes dissolved inorganic carbon (D IC) accumulation in these low-C02 grown cells. 
  Reference    Z. Naturforsch. 51c, 40—4 (1996); received August 4/October 6 1995 
  Published    1996 
  Keywords    Quantum Requirement, Fluorescence, Dissolved Inorganic Carbon, Anabaena variabilis, Anacystis nidulans 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0040.pdf 
 Identifier    ZNC-1996-51c-0040 
 Volume    51 
8Author    W.I G Ruszeckia, K. Strzałk, K.P B Ad Erc, A. R. Adunzc, G. H. SchmRequires cookie*
 Title    Involvement of the Xanthophyll Cycle in Regulation of Cyclic Electron Flow around Photosystem II  
 Abstract    In our previous study (Gruszecki et al., 1995) we have postulated that the mechanism of cyclic electron transport around photosystem II, active under overexcitation of the photosyn­ thetic apparatus by light is under control of the xanthophyll cycle. The combination of dif­ ferent light quality and thylakoids having various levels o f xanthophyll cycle pigments were applied to support this hypothesis. In the present work photosynthetic oxygen evolution from isolated tobacco chloroplasts was measured by means o f mass spectrometry under conditions of high or low levels of violaxanthin, being transformed to zeaxanthin during dark incubation in an ascorbate containing buffer at pH 5.7. Analysis of oxygen evolution and o f light-induced oxygen uptake indicate that the de-epoxidation o f violaxanthin to zeaxanthin results in an increased cyclic electron transport around PS II, thus dimishing the vectorial electron flow from water. An effect similar to de-epoxidation was observed after incubation of thylakoid membranes with specific antibodies against violaxanthin. 
  Reference    Z. Naturforsch. 51c, 47 (1996); received September 22/O ctober 18 1995 
  Published    1996 
  Keywords    Xanthophyll Cycle, Cyclic Electron Flow, Photosystem II, Oxygen Evolution, Blue Light Effect, Mass Spectrometry 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0047.pdf 
 Identifier    ZNC-1996-51c-0047 
 Volume    51 
9Author    C. Hristine, M. R. Ichter, U. Lrich Eis, A. Loysius WildRequires cookie*
 Title    Phenolic Compounds as a Tool of Bioindication for Novel Forest Decline at Numerous Spruce Tree Sites in Germany  
 Abstract    Within a project that applied biochemical criteria to the diagnosis of damage to Norway spruce, 43 sites in western and eastern Germany showing only moderate tree damage were screened for the amounts of methanol soluble phenolic compounds in spruce needles. The concentrations of most of the main compounds -especially catechin -positively correlated with needle loss and the altitude of the site. It was also found that it is necessary to differenti­ ate between trees younger and older than 60 years of age. The correlations between the increase of the phenolic compounds studied and the needle loss or the damage class are stronger in the younger trees, possibly implicating differences in metabolic state or distur­ bances in protectective mechanisms in the older trees. 
  Reference    Z. Naturforsch. 51c, 53—58 (1996); received September 20/0ctober 6 1995 
  Published    1996 
  Keywords    Phenolic Compounds, Catechin, Novel Forest Decline, Correlations, Picea abies 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0053.pdf 
 Identifier    ZNC-1996-51c-0053 
 Volume    51 
10Author    W. Ilhelm, K. Em, M. ErlingRequires cookie*
 Title    Toxicity of Palicourea marcgravii: Combined Effects of Fluoroacetate, N-methyltyramine and 2-Methyltetrahydro-ß-carboline  
 Abstract    Palicourea marcgravii, N-methyltyramine, 2-Methyltetrahydro-ß-carboline, co-Fluorofatty Acid, Fluoroacetate Feeding experiments carried out with cattle and horses could prove the toxic effects of P. marcgravii (Rubiaceae) in all cases. The typical symptoms of "sudden death", however, are observed in ruminants only. This difference could not be explained so far. A part from fluoroacetate, two more substances also have influence the toxic effects and have been isolated from P. marcgravii for the first time: N-methyltyramine and 2-methyltetra-hydro-ß-carboline (2-Me THBC). Structure elucidation of these compounds is mainly accom­ plished by "H-NM R, I3C-NMR and MS techniques. Due to the small quantity of fluoroacetate (5.4 jig/g plant), the main toxic effect obviously lies in the two discovered substances. In contrast to the slow death of horses (monogastriers), the "sudden death syndrome" of cattle (ruminants) can be explained as a result of the higher resorbility of these two substances in the gastro-intestinal system. Given orally, both substances influence the monoamine oxidase type A (MAO-A): N-methyltyramine acts as a competitive substrate, and 2-Me THBC is one of the most effective MAO-A-inhibitors. Thus, the decomposition of the specific M AO-A-substrates noradrenaline and adrenaline as well as of N-methyltyramine itself is inhibited. The a-and ß-receptors of the sympathetic system are stimulated more strongly, which leads to a drastic rise in blood pressure and thereby to a more rapid distribution of fluoroacetate in the body. This results in a reinforced input of fluoroacetate in the cells of especially active organs of the body (heart etc.). Thus, even smaller quantities of fluoroacetate are lethal. 
  Reference    Z. Naturforsch. 51c, 59—64 (1996); received November 7/Dezember 4 1995 
  Published    1996 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0059.pdf 
 Identifier    ZNC-1996-51c-0059 
 Volume    51 
11Author    A. N. Ery Da, M. Attaac, C. B. Silvab, A. H. Assó N-VolochbRequires cookie*
 Title    Effect of Mg2+-ATP on Acetylcholinesterase of Electrophorus electricus (L.)  
 Abstract    Acetylcholinesterase, Electrophorus electricus (L.), Mg2+-ATP The effect of Mg2+-ATP on purified acetylcholinesterase (AChE) from electric tissue of Electrophorus electricus (L.) was studied. The enzymatic activities were measured with acetylcholine and acetylthiocholine as substrates. The kinetic parameters Vmax, Km and Hill coefficient (nH), for acetylcholine and acetylthiocholine were modified with Mg2+-ATP. It was shown that acetylcholinesterase presents an apparent activation at high concentration of substrates and an inhibition in the presence of Mg2+-ATP at low concentration of acetylcho­ line and acetylthiocholine. In addition, the data suggest that Mg2+-ATP induced an allosteric modulation of the acetylcholinesterase obtained from Electrophorus electricus (L.), and indi­ cate an active adenosine triphosphate participation during cholinergic activity. 
  Reference    Z. Naturforsch. 51c, 65—6 (1996); received July 17/Septem ber 8 1995 
  Published    1996 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0065.pdf 
 Identifier    ZNC-1996-51c-0065 
 Volume    51 
12Author    B. Erto, D. Ias Lins, T. Hereza, A. M. Elia Soares, R. Icardo, F. ErreiraRequires cookie*
 Title    Plural Origins of the Molecular Homochirality in Our Biota  
 Abstract    Origin of Homochirality, Handedness of Biomolecules, d -l Nucleotides, d -l Amino Acids We d e sc rib e re su lts o f c o m p u te r sim u la tio n c alc u la tio n s o f m ix ed a n d h o m o c h ira l olig o ri-b o tid e s sh o w in g th a t it is p o ssib le to b in d L (D)-m onom ers a t th e te rm in a l p o sitio n s o f c h ain s b u ilt fro m D (L)-ribotides, b u t in se rtio n a t in te rn a l p o sitio n s p ro d u c e s a larg e in sta b ility o f th e chains. C o u p le d w ith a p ro p o se d n ew m ec h an ism fo r th e g ro w th o f th e s e lin e a r p o ly m e rs in p re b io tic c o n d itio n s, o u r re su lts im ply th a t e n a n tio m e ric c ro ss-in h ib itio n c o u ld h av e b e e n b y p a sse d to m a k e all-D(L) o lig o rib o tid e s d o m in a n t. We also sh o w th a t ra c e m ic a m in o acids can fo rm sta b le p e p tid e ß -stra n d s, w hich ru le s o u t a sim ila r o rig in fo r m o d e rn L -am ino acids. A lte rn a tiv e sc h e m e s a re p ro p o se d to a c c o u n t fo r th e h o m o c h ira litie s o f th e a m in o acids a n d o f o th e r b io m o lecu les. 
  Reference    Z. Naturforsch. 51c, 70—74 (1996); received August 15/O ctober 19 1995 
  Published    1996 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0070.pdf 
 Identifier    ZNC-1996-51c-0070 
 Volume    51 
13Author    Requires cookie*
 Title    The Influence of Alkoxymethyl Purine and Pyrimidine Acyclonucleosides on Growth Inhibition of Kirkman-Robbins Hepatoma and Possible Mechanism of Their Cytostatic Activity  
  Reference    Z. Naturforsch. 51c, 75 (1996) 
  Published    1996 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0075.pdf 
 Identifier    ZNC-1996-51c-0075 
 Volume    51 
14Author    JerzyRequires cookie*
 Title    Evidence of Surface Diffusion of Water Molecules on Proteins of Rabbit Lens by NMR Relaxation Measurements  
 Abstract    B o d u rk a 3, G e rd B untkow skyb, A leksander G utsze3, H ans-H einrich L im bachb a D epartm ent In this work, we propose a relaxation model for the interpretation of NMR proton spin-lattice and spin-spin relaxation times of mammalian lenses. The framework for this model is based on nuclear magnetic spin-lattice relaxation measurements as a function of tem perature at different Larmor frequencies for whole rabbit lenses and fragments of the lens. According to this model, two different dynamic processes of the water molecules determine the relax­ ation behaviour, namely rotational diffusion and translational surface diffusion. These dy­ namic processes in conjuction with a two site exchange model give a good explanation of all the measured relaxation data. From the experimental data, we were able to obtain the activa­ tion param eters for rotational and translational diffusion of bound lens water. Correlation times of 2.1xl0~n sec and 2.5xl0~9 sec and activation energies of 20.5 kJ/mol and 22.5 kJ/mol respectively were found at 308K. At low Larmor frequencies (<100 MHz) the longitudinal relaxation is mainly determ ined by translational surface diffusion of bound water with a mean square displacement of 1.5 nm, whereas at higher frequencies (>300 MHz), rotational diffusion is the main relaxation mechanism. The spin-spin relaxation is determ ined by transla­ tional diffusion over the whole frequency range and therefore shows only a very small disper­ sion. By our model it is possible to explain: 1) the strikingly large difference between the T[ value and the T2A and T2B values observed in the lens and 2) the different values of the activation energies measured at different fields for the lens. 
  Reference    Z. Naturforsch. 51c, 81 (1996); received August 8 /Decem ber 7 1995 
  Published    1996 
  Keywords    'H NMR, Relaxation Times Water, Suface Diffusion, Rabbit Lens 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0081.pdf 
 Identifier    ZNC-1996-51c-0081 
 Volume    51 
15Author    M. Einrad Boll3, L. Utz, W.D W Eberb, A., Stam Reas, PflbRequires cookie*
 Title    The Response of Rat Serum Lipids to Diets of Varying Composition or Contaminated with Organochlorine Pesticides  
 Abstract    The effects of different diets (high carbohydrate, high protein, high fat) and diets contami­ nated with polychlorinated biphenyls (PCBs) and/or y-hexachlorocyclohexane (lindane) on the levels of serum triglycerides, cholesterol and phospholipids were investigated in Wistar rats. Serum triglyceride levels differed significantly among the diets, while those of cholesterol and phospholipids were much less affected by the diet composition. A change in diet compo­ sition resulted in a gradual adaptation to the lipid levels characteristic of the new diet with major variations including oscillations. There was, however, no specific component of a diet that could be associated with any specific change in serum lipids. While feed deprivation decreased the serum lipids (40-65% in 3 days), refeeding the starved animals caused pro­ nounced increases of the lipids that were different among the diets. The response of the triglyceride levels was the strongest (up to 1 0 times the starvation levels) followed by those of the phospholipids (4-fold) and cholesterol (2.5-fold). Response of the triglyceride levels peaked within 1 or 2 days of refeeding, whereas those of cholesterol and phospholipids took 4 days to reach the maximum. Feeding PCB-contaminated diets increased the serum lipids in a dose-dependent manner (15-250 ppm). Higher PCB concentrations were increasingly inhibitory (350 ppm) or overtly toxic (> 400 ppm). Elevated lipids returned to the starting levels immediately after peaking (triglycerides) or only after several days (cholesterol, phospholipids) but with an earlier onset at lower PCB concentrations. Refeeding starved animals with PCB-contaminated diets also increased the serum lipids dose-dependently. Feeding lindane-containing diets (50-150 ppm) as well as refeeding animals with lindane diets resulted in a considerable increase of the triglyceride levels, while cholesterol and phos-pohlipids increased much less. Higher lindane concentrations (250 ppm) were inhibitory. The outcome on serum lipid levels on feeding diets contam inated with both PCBs and lindane was basically additive. 
  Reference    Z. Naturforsch. 51c, 91—100 (1996); received Septem ber 9/November 6 1995 
  Published    1996 
  Keywords    Serum Lipids, Rat, Diet Composition Polychlorinated Biphenyls, y-Hexachlorocyclohexane (Lindane) 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0091.pdf 
 Identifier    ZNC-1996-51c-0091 
 Volume    51 
16Author    G. Eorg Stom, M. El, D. Arlies, G. Orlöchter, Rüsing Abriele, H. Ennig StieveRequires cookie*
 Title    The Light-Stimulated Cytosolic Calcium Transient in Limulus Ventral Nerve Photoreceptors: Two Components in the Rising Phase  
 Abstract    O ctober 24, 1995 Arsenazo Signal, Cytosolic Calcium Transient, Lithium 1. Light-evoked electrical responses were measured in Limulus ventral nerve photorecep­ tors simultaneously with changes in the cytosolic free calcium concentration, by means of arsenazo III. 2. It has been shown here for the first time that the rise of the arsenazo signal consists of two phases. Only the slow phase in the rise of the signal depends on the membrane voltage. The reversal potential of the amplitude of this slow rising phase was about +196 mV. After removal of external calcium the reversal potential was about +20 mV. 3. When Na+ in the superfusate was replaced by Li+, the amplitude of the fast rising phase was reduced on the average to 50%, while the slow rising phase was not affected. 4. We conclude that the fast rising phase is caused by release of calcium from internal stores while the slow increase in [Ca2+]j is due to influx across the plasma membrane, possibly through light-activated ion channels. 
  Reference    Z. Naturforsch. 51c, 101—112 (1996); received 
  Published    1996 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0101.pdf 
 Identifier    ZNC-1996-51c-0101 
 Volume    51 
17Author    J.Manuel DenucéRequires cookie*
 Title    Enzymatischer Abbau der Embryonalhüllen des Lanzettfischchens, Branchiostoma lanceolatum, während des Schlüpfens Hatching through Enzymatic Breakdown of the Embryonic Coats in the Lancelet, Branchiostoma lanceolatum (Cephalochordata)  
 Abstract    B ran ch iostom a lanceolatum , A m ph ioxu s, Hatching Enzyme, Metalloproteinase A study was made of the hatching process of the lancelet, B ran ch iostom a lanceolatum {A m p h io x u s), under laboratory conditions. Embryos in the early neurula stage (5 to 6 pairs of somites) escape through a hole made in the fertilization envelope, following intensive rotatory movements and partial digestion of the envelope. Using the chromogenic substrate Hide Powder Azure (HPA) at pH 8.0, proteolytic activity was detected in the hatching me­ dium. The effect of various protease inhibitors was investigated. Whereas the activity was only slightly affected by inhibitors of trypsin, chymotrypsin or thiol proteases, chelating agents such as EDTA and 1,10-phenanthroline prevented the degradation of HPA, as well as the breakdown of the vitelline membrane of alcohol fixed oocytes by the protease from hatching fluid. These data suggest the presence of a metalloprotease in the hatching medium. How far this enzyme can be compared with hatching enzymes found in echinoderms and fishes (where they have been identified as matrix degrading metalloproteases), awaits further study of the lancelet enzyme, including its isolation and purification. 
  Reference    Z. Naturforsch. 51c, 113—118 (1996); received September 8/October 23 1995 
  Published    1996 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0113.pdf 
 Identifier    ZNC-1996-51c-0113 
 Volume    51 
18Author    Karol Bialkowski, Piotr Cysewski, Ryszard OlinskiRequires cookie*
 Title    E ffect o f 2 '-D eo x y guanosine O xidation at C 8 Position on N -G lycosidic B ond Stability  
 Abstract    8-Oxo-2'-deoxyguanosine, 8-Oxoguanine, 8 -Hydroxyguanine, Base Modification, DNA Oxidative Damage The influence of 2'-deoxyguanosine (dG) oxidation at the C-8 position on N-glycosidic bond stability was in­ vestigated. A kinetic analysis of dG and 8-oxo-2'-deoxy-guanosine (8-oxodG) depurination reactions was carried out in water solutions at pH ranging from 2 to 7.4 and temperature of 100 °C. The results indicate that N-glyco­ sidic bond of 8-oxodG is significantly more stable in comparison with dG at any pH applied. At pH 5.1 hy­ drolysis rate of dG is 4.5-fold higher than that for 8-oxodG. The chemical stability of the modified nucleo­ side in oxidatively damaged DNA is one of important factors contributing to its mutagenic potential. Results of our experiments indicate that 8-oxodG, potentially mutagenic and carcinogenic nucleoside, is hardly suscep­ tible to spontaneous depurination and its removal from cellular DNA depends mostly on the activity of DNA repair enzymes. 
  Reference    Z. Naturforsch. 51c, 119—122 (1996); received November 8 /December 15 1995 
  Published    1996 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0119_n.pdf 
 Identifier    ZNC-1996-51c-0119_n 
 Volume    51 
19Author    Sabine RosahlRequires cookie*
 Title    Lipoxygenases in Plants -Their Role in Development and Stress Response  
 Abstract    Lipoxygenases catalyze the hydroperoxidation of polyunsaturated fatty acids and thus the first step in the synthesis of fatty acid metabolites in plants. Products of the LOX pathway have multiple functions as growth regulators, antimicrobial compounds, flavours and odours as well as signal molecules. Based on the effects of LOX products or on the correlation of increases in LOX protein and the onset of specific processes, a physiological function for LOXs has been proposed for growth and development and for the plant response to patho­ gen infection and wound stress. 
  Reference    Z. Naturforsch. 51c, 123—138 (1996); received September 1995 
  Published    1996 
  Keywords    Wounding, Pathogen, Jasmonic Acid, Oxylipins 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0123.pdf 
 Identifier    ZNC-1996-51c-0123 
 Volume    51 
20Author    E. M. Schaffner3, R. H. Artm Ann0, K. Taraz3, H. Budzikiewicz3Requires cookie*
 Title    Structure Elucidation of Azotobactin 87, Isolated from Azotobacter vinelandii ATCC 12837*, ** The sequence L-Ser- D-Ser-L-Hse-Gly-D-r/zreo-OHAsp-Hse-Hse-Hse-D-N;'OH-N5-R-Hbu-Om-L-Hse was deter­ mined for Az 87-1, while Az 87-11 contains a C-terminal L-Hse-lactone instead  
 Abstract    Frau P ro fesso r M arianne B ä u d ler zu m 75. G eb u rtsta g g e w id m e t A zo to b a c te r vin elan dii, Azotobactin, Siderophore Chromopeptide siderophores (azotobactin 87-1 and -II) were isolated from an iron deficient culture medium of A z o to b a c te r vin elandii ATCC 12837 (=DSM 87). Their structures were elu­ cidated by chemical degradation studies and spectroscopic methods, especially 2D-NMR-tech-niques. Total assignments of 'H-, 13C-, and 15N-resonances based on 2D-HOHAHA-, 'H/13C-HMQC-, 'H /13C-HMBC-, 'H /15N-HMQC/TOCSY-, and 'H/'^N-HMBC-experiments are given as well as sequential information derived from 'H/'H-NOESY-, 'H /I3C-HMBC-and 'H/ 13N-HMBC-experiments. Both Az 87-1 and Az 87-11 consist of a tetracyclic chromophore -(lS)8,9-dihydroxy-4-oxo-2,3,4,5-tetrahydro-l//,10c//-3a,5,10b-triazaacephenantrylene-l-carb-oxylic acid -and a decapeptide chain linked with the N-terminus to the carboxy group of the chromophore containing also modified, non-proteinogenic amino acids.. Iron is chelated by the catecholic group of the chromophore, the ß-hydroxy aspartic acid, and the hydroxamate function formed by N^-hydroxyornithine and /?-ß-hydroxybutyric acid. 
  Reference    Z. Naturforsch. 51c, 139—150 (1996); received December 11. 1995/January 22 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0139.pdf 
 Identifier    ZNC-1996-51c-0139 
 Volume    51 
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