| | 6 | Author
| M. Hillerbrand, W. Lohmann, V. Penka, U. Ehling | Requires cookie* | | | Title
| Charge Transfer Interactions between Isonicotinic Acid Hydrazide and Cupric Ions  | | | | Abstract
| Isotonic Acid Hydrazide, Charge-Transfer Interaction, Metal Ions The interaction of Cu2+ with isonicotinic acid hydrazide (INH) and some of its derivatives has been investigated by means of electron spin resonance, nuclear magnetic resonance, and optical absorption studies. It could be shown that an interaction exists between the metal ions and the hydrazine side chain in addition to the very weak interaction with the ring nitrogen. The results obtained indicate the formation of a charge transfer complex. | | | |
Reference
| (Z. Naturforsch. 30c, 33 [1975]; received August 26 1974) | | | |
Published
| 1975 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/30/ZNC-1975-30c-0033.pdf | | | | Identifier
| ZNC-1975-30c-0033 | | | | Volume
| 30 | |
| 7 | Author
| G. Hauska, W. Oettmeier, S. Reimer, A. Trebst | Requires cookie* | | | Title
| Shuttles of Artificial Electron Donors for Photosystem I Across the Thylakoid Membrane | | | | Abstract
| Photosynthesis, Energy Conservation, Phosphorylation, Uncoupler Mechanism NADP+ reduction in isolated chloroplasts of spinach by photosystem I at the expense of various artificial donor systems is not inhibited by the plastoquinone antagonist dibromothymoquinone. The coupled ATP formation in such photoreductions is attributed to an artificial energy conserving site, i. e. a proton liberation during oxidation of the donor at the inner surface of the thylakoid membrane. Some donor systems for photosystem I are stimulated by uncouplers whereas others are not. The stimulation shows no correlation to the efficiency of the coupled photophosphorylation. Instead a correlation of the stimulation by uncouplers to the presence of an acidic OH-group in the donor molecule is seen. The uncoupler effect is therefore not explained by a release of electron transport control by the high energy state but rather by a pH-dependent distribution of the donor compound across the membrane. This is supported by the properties of donor systems in sonicated chloroplast particles with external oxidation sites of photosystem I. | | | |
Reference
| (Z. Naturforsch. 30c, 37 [1975]; received October 31 1974) | | | |
Published
| 1975 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/30/ZNC-1975-30c-0037.pdf | | | | Identifier
| ZNC-1975-30c-0037 | | | | Volume
| 30 | |
| 8 | Author
| Secundino Del Valle-Tascón, JuanM. Ramírez | Requires cookie* | | | Title
| Origin of the ATP Formed during the Light-Dependent Oxygen Uptake Catalyzed by Rhodospirillum rubrum Chromatophores | | | | Abstract
| Photophosphorylation, Photooxidase, Rhodospirillum rubrum The oxygen uptake which is observed when Rhodospirillum rubrum chromatophores are illumi nated under air and in the presence of reduced 2,6-dichlorophenolindophenol (DCIP), 2,3,5,6-tetra-methyl-p-phenylenediamine (diaminodurene, DAD) or N,N'-tetramethyl-p-phenylenediamine (TMDP) depends on the electron-donor concentration according to the equation of Michaelis-Menten. The apparent K m for the donor is lowered by the electron-transfer inhibitor 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO) which causes therefore a stimulation of the rate of the reaction at non-saturating concentrations of the donors. In contrast, the ATP formation which takes place simultaneously to oxygen uptake does not show an enzyme-like dependence on donor concentration. Moreover it is inhibited by HQNO to a variable extent, depending on the particular donor present and on its concentration. Therefore it appears that the HQNO-sensitive phosphorylation is coupled to a cyclic flow which coexists and competes with the non-cyclic flow from donor to oxygen. In the presence of HQNO, substrates and uncouplers of ATP formation accelerate somewhat the rate of the oxygen uptake supported by reduced DCIP and DAD. Thus part of the HQNO-resistant phosphorylation seems to be associated with the non-cyclic flow from those two donors to oxygen. The lack of stimulation by phosphorylation or by uncoupling of the TMPD-supported oxygen uptake does not permit a conclusion as to whether this reaction is coupled to ATP forma tion or not. Another part of the HQNO-resistant ATP formation is independent of the presence of oxygen and appears to be associated to cyclic flows which bypass the HQNO site. This type of phosphoryla tion is most important in the presence of TMPD. | | | |
Reference
| (Z. Naturforsch. 30c, 46 [1975]; received October 7 1974) | | | |
Published
| 1975 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/30/ZNC-1975-30c-0046.pdf | | | | Identifier
| ZNC-1975-30c-0046 | | | | Volume
| 30 | |
| 9 | Author
| ErichF. Elstner, Claus Stoffer, Adelheid Heupel | Requires cookie* | | | Title
| Determination of Superoxide Free Radical Ion and Hydrogen Peroxide as Products of Photosynthetic Oxygen Reduction | | | | Abstract
| Formation of Nitrite from Hydroxylamine in the presence of illuminated chloroplast lamellae is inhibited by superoxide dismutase but not by catalase, indicating that the superoxide free radical ion and not H20 2 is responsible for the oxidation of hydroxylamine. Decarboxylation of a-keto acids on the other hand is strongly inhibited by catalase but only slightly by superoxide dismutase. Light-dependent hydroxylamine oxidation and decarboxylation of a-keto acids can be used, there for, as specific and sensitive probes for the determination of either the superoxide free radical ion or hydrogen peroxide, respectively. Photosynthetic oxygen reduction in the presence of ferredoxin, (monitored by the above method) yields both H20 2 and 0 2 ". The addition of an oxygen reducing factor (ORF, solubilized by heat — treatment of washed chloroplast lamellae) instead of ferredoxin, however, stimulates only the production of H20 2 , while 0 2'~ — formation is not observed. The cooperation of ferredoxin and ORF during photosynthetic oxygen reduction by chloroplast lamellae apparently produces H20 2 not only by dismutation of 0 2'~, but also by a separate mechanism involving ORF. yields only in the formation of H20 2 . The coopera tion of Fd and ORF in photosynthetic oxygen re duction provides a system which is able to produce HoOo and 0 2~ simultanuously. During photosyn thetic oxygen reduction, H 20 2 is not only the product of the dismutation of the superoxide free radical ion according to Eqn (1) 0 2'-+ Oo ~ + 2 H +-> H2Oo + 0 2 (1) but is separately formed by a mechanism which includes the function of ORF. Material and Methods Ferredoxin was isolated from spinach leaves9 and SOD from dried green peas 10, 5. Chloroplasts were isolated either from spinach 11 or from sugar beet leaves12' 7. ORF was prepared from isolated chloroplast lamellae 7 from either spinach or sugar beet leaves. Photosynthetic decarboxylation of [l-14C]gly-oxylate13, NADP-reduction13 and nitrite-forma-tion 14 from hydroxylamine were measured as de scribed. Sugar beet leaves (greenhouse cultures) were a gift from the Kleinwanzlebener Saatzucht AG, Einbeck/Hann. [1-14C] sodium glyoxylate was obtained from the Radiochemical Center, Amersham. Catalase was purchased from Boehringer, Mannheim. | | | |
Reference
| (Z. Naturforsch. 30c, 53 [1975]; received October 25 1974) | | | |
Published
| 1975 | | | |
Keywords
| Chloroplasts, Oxygen Reduction, Hydroxylamine Oxidation, Superoxide Free Radical Ion | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/30/ZNC-1975-30c-0053.pdf | | | | Identifier
| ZNC-1975-30c-0053 | | | | Volume
| 30 | |
| 10 | Author
| ErichF. Elstner, JörgR. Konze | Requires cookie* | | | Title
| Ethylene Formation by Isolated Chloroplast Lamellae in the Dark | | | | Abstract
| Ethylene Biosynthesis, Chloroplasts, Superoxide Free Radical Isolated chloroplast lamellae from spinach produce ethylene in the dark from methylmercapto-propanal (MMP) or from 2-keto-4-methyl-mercaptobutyrate (KMB) only in the presence of both NADPH and ferredoxin. Anthraquinone-2-sulfonic acid can substitute for ferredoxin. Catalase, superoxide dismutase, ethanol and ascorbate are inhibitors of NADPH-dependent ethylene forma tion. Isolated NADP-ferredoxin reductase in the presence of NADPH, ferredoxin and an oxygen reducing factor (ORF, isolated by heat-treatment of chloroplast lamellae) catalyzes ethylene formation from the above substrates in the dark without chloroplast lamellae. From the results it is concluded that chloroplast lamellae in the dark can reduce oxygen monovalently at the expense of NADPH, with the production of the OH-radical as the reactive species responsible for ethylene formation from MMP of KMB. | | | |
Reference
| (Z. Naturforsch. 30c, 58 [1975]; received November 7 1974) | | | |
Published
| 1975 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/30/ZNC-1975-30c-0058.pdf | | | | Identifier
| ZNC-1975-30c-0058 | | | | Volume
| 30 | |
| 11 | Author
| HartmutK. Lichtenthaler, HansK. Kleudgen | Requires cookie* | | | Title
| Phytochromsystem und Lipochinonsynthese in den Plastiden etiolierter Hordeum-Keimlinge Phytochrome System and Synthesis of Lipoquinones in the Plastids of Etiolated Hordeum Seedlings | | | | Abstract
| Phytochrome, Plastoquinone-9, Lipoquinone Synthesis, Etioplast Metabolism Short pulses of red light induce in etiolated barley seedlings an enhanced synthesis of plastidic benzoquinones and vitamin Kt , which can be reverted by subsequent irradiation with short pulses of far-red. As compared to the dark there is more formation of plastoquinone-9 than a-tocopherol. The enhanced formation of vitamin Kx is coupled with a concomitant decrease in the level of the second naphthoquinone vitamin "K". The data show that active phytochrome Pfr , also in its ground state, induces the light triggered lipoquinone synthesis which is connected to thylakoid formation. The red light induction of enhanced plastoquinone-9 synthesis cannot be fully reverted by subsequent far-red and seems to be a very fast phytochrome response. | | | |
Reference
| (Z. Naturforsch. 30c, 64 [1975]; eingegangen am 31. Oktober 1974) | | | |
Published
| 1975 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/30/ZNC-1975-30c-0064.pdf | | | | Identifier
| ZNC-1975-30c-0064 | | | | Volume
| 30 | |
| 13 | Author
| U. Kull, B. Kühn | Requires cookie* | | | Title
| Influence of Zeatin and Gibberellin on Adenosine-3',5'-Cyclic Monophosphate Levels of Impatiens Leaves | | | | Abstract
| Adenosine-3',5'-Cyclic Monophosphate, Cytokinin, Gibberellin, Theophylline, Impatiens The content of adenosine-3',5'-cyclic monophosphate (cAMP) in leaves of Impatiens sultani Hook, was measured by a protein-binding assay. A preceding administration of the natural cyto kinin zeatin causes a diminution of the cAMP level. Administration of gibberellin (GA3) does not bring about any variations. There is no indication that cAMP is acting as a secondary messenger of either phytohormone. Theophylline does not increase the content of cAMP found in the leaves. | | | |
Reference
| (Z. Naturforsch. 30c, 69 [1975]; received August 21/October 4 1974) | | | |
Published
| 1975 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/30/ZNC-1975-30c-0069.pdf | | | | Identifier
| ZNC-1975-30c-0069 | | | | Volume
| 30 | |
| 15 | Author
| HansG L Coster, Ulrich Zimmermann | Requires cookie* | | | Title
| Direct Demonstration of Dielectric Breakdown in the Membranes of Valonia utricular is | | | | Abstract
| Dielectric Breakdown, Cell Membrane, Valonia utricularis It is shown that if the membrane potential of cells of Valonia utricularis was increased rapidly by applying ~500 /us current pulses, dielectric breakdown of the membrane occured when the potential reached a value of ~0.85 V. The breakdown phenomenon observed was not associated with global damage to the cell or its membrane. The process could be repeated after a short resealing time (~ 10s), many times on a single cell. The rapidity of the breakdown process (~1 us) rules out the possibility that dielectric break down occurs by a mechanism similar to that of punch-through, which involves changes in ionic profiles. | | | |
Reference
| (Z. Naturforsch. 30c, 77 [1975]; received September 30 1794) | | | |
Published
| 1975 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/30/ZNC-1975-30c-0077.pdf | | | | Identifier
| ZNC-1975-30c-0077 | | | | Volume
| 30 | |
| 16 | Author
| Dietmar Todt | Requires cookie* | | | Title
| Irrtümer beim Maschineschreiben und ihr Hinweis auf Systemeigenschaften zentraler Entscheidungsmechanismen Errors in Type-writing and Their Indications for Special Characters of the Data Processing Controlling the Typing Process | | | | Abstract
| Twenty students having a comparable typing skill and speed (about 150 strokes per min) per formed series of typewritings with contents well familiar to them. These writings were examined for errors (error = deviation from a given program of stroke sequences). The errors could not be caused by ingnorance of writing or spelling of the words. Two categories of errors ("exchanges" = "Verwechslungen" and "omissions" = "Auslassungen") were explained to result from special "faults" in the data processing controlling the typing process (Fig. 3). The occurrence of these types of errors dependend on interactions of the following factors: 1. Preferences of succession which (in general) related the first letter of an actual letter-combina-tion with the second one (also) in contrary succession (i ^ e) or with other letters, not occur ring in the combination (n — > d ; n — * ■ g) (Tab. I) . 2. Tendencies of the particular letters of an actual sequence of letters (= word) to occur already before and/or after the right sequential position (sequential interval of this effect <= 4 strokes; temporat interval: about 1 sec; Figs 1, 2). 3. Correspondences in particular characteristics of special letters (vowel-vowel-exchange, etc.). 4. The notice to type as quickly as possible. Interactions of these factors resulted in erroneous "anticipations" and "postpositions" of letters. | | | |
Reference
| (Z. Naturforsch. 30c, 80 [1975]; eingegangen am 30. Juli/21. Oktober 1974) | | | |
Published
| 1975 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/30/ZNC-1975-30c-0080.pdf | | | | Identifier
| ZNC-1975-30c-0080 | | | | Volume
| 30 | |
| 17 | Author
| Kuno Kirschfeld, M. Lindauer, H. Martin | Requires cookie* | | | Title
| Problems of Menotactic Orientation According to the Polarized Light of the Sky | | | | Abstract
| Bee, Meno-polarotaxis j £ It is shown that the knowledge of the E-vector direction of the linearly polarized light at any point of the sky alone is insufficient for the determination of the position of the sun. If the E-vector direction of a second point is not known the knowledge of at least one other parameter is necessary. This parameter might be the height of the sun over the horizon. With the knowledge of the height the infinite number of solutions for the sun's position becomes reduced to two, or in special cases to one. These cases are derived. | | | |
Reference
| (Z. Naturforsch. 30c, 88 [1975]; received October 9 1974) | | | |
Published
| 1975 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/30/ZNC-1975-30c-0088.pdf | | | | Identifier
| ZNC-1975-30c-0088 | | | | Volume
| 30 | |
| 18 | Author
| M. Von Ardenne, A. Von, Ardenne Forschungsinstitut, Manfred Von Ardenne, Dresden-Weißer Hirsch | Requires cookie* | | | Title
| Gesetzmäßigkeiten der Substratversorgung, der Zellkinetik und der Therapiemechanismen im Interkapillarraum der Krebsgewebe Laws of Substrate Supply, of Cell Kinetics and of Therapy Mechanisms in the Intercapillary Region of Cancer Tissue | | | | Abstract
| Up to now, the microtopography of glucose and 0 2 concentration in the intercapillary region of tumour tissue has been determined under the simplifying assumption that substrate consumption is constant up to the periphery of the envisaged cylindrical space around a capillary. The general diffusion field equation presented in this paper takes into account that substrate consumption decreases in the unsaturated region of cancer cell glycolysis and respiration so that — compared to former computations — the critical supply radii needed for maintained proliferation increase by a factor of almost 1.8. With the aid of its general solution and the discussed parameters, the laws governing substrate supply, cell kinetics and therapy mechanisms in the intercapillary region of intact and treated tumour tissue are presented and discussed. The essential results there are as follows: — Even in case of hyperglycemia it is glucose supply (and not the 0 2 supply) which determines proliferation and proliferation rate. — Under the conditions of longtime-hyperglycemia (400 mg%), the tumour volume being accessible to the attack of cancerostatica or radiation, is almost three times as high as under standard conditions. — For glucose (and cancerostatica) the time constant for interactions between circulation and tumour tissue near the necrotic region is equal to or greater than 400 min. This is why stimulation of cancer cell glycolysis in the most therapy-resistant cancer cell portions (i. e., increased proliferation rate and tumour hyperacidifica tion) can only be achieved if hyperglycemia is maintained for 24 hours or more. — Therapeuti cally treated cancer tissue is characterized by the discussed changes in the diffusion field of glucose and 0 2 as well as a drop in the interaction time constant for glucose. 1. Die Bedeutung der Gesetzmäßigkeiten im Interkapillarraum der Krebsgewebe für den K am pf gegen die Krebskrankheit | | | |
Reference
| (Z. Naturforsch. 30c, 91—106 [1975]; eingegangen am 28. Juni/21. Oktober 1974) | | | |
Published
| 1975 | | | |
Keywords
| Gewidmet dem Andenken an Max Bürger, Leipzig Diffusion Field Equation, Hyperglycemia, Cancer Cell Proliferation, Intercapillary Region, Cancer Multi-step Therapy | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/30/ZNC-1975-30c-0091.pdf | | | | Identifier
| ZNC-1975-30c-0091 | | | | Volume
| 30 | |
| 20 | Author
| B. E. Leonard | Requires cookie* | | | Title
| The Effect of 5-Hydroxytryptamine and Histamine on Glycolysis in the Mouse Brain | | | | Abstract
| B rain Glycolysis, Serotonin, Histamine Following the intraventricular injection of 5-hydroxytryptamine into the lateral ventricles of conscious mice, the concentration of brain lactate rose imm ediately but then decreased significantly compared with the saline injected controls. The concentration of brain glucose increased 20 min after the injection of 5-hydroxytryptam ine. These effects of 5-hydroxytryptamine on lactate and glucose were qualitatively sim ilar to those found following the adm inistration of m ethysergide. After the parenteral adm inistration of 5-hydroxytryptophan, the lactate levels showed a biphasic change but brain glucose was significantly decreased for up to 90 min following the injection. p-Chlorophenylalanine potentiated the effect of 5-hydroxytryptamine by further increasing glucose and decreasing lactate levels. A fter histam ine had been injected into the ventricles, the concen trations of bound glycogen and lactate were decreased whereas free glycogen and glucose were raised. It is suggested th at 5-hydroxytryptam ine, and possibly histam ine, are involved with control of glycolysis in the mouse brain. | | | |
Reference
| (Z. Naturforsch. 30c, 113 [1975]; received August 8/October 2 1974) | | | |
Published
| 1975 | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_C/30/ZNC-1975-30c-0113.pdf | | | | Identifier
| ZNC-1975-30c-0113 | | | | Volume
| 30 | |
|
