Showing papers by "Ludwig Maximilian University of Munich published in 1985"
TL;DR: These peptides appear upon induction of plant cells with heavy metals and represent the principal metal-binding activities in the cells and are proposed as phytochelatin for this new class of natural products.
Abstract: A set of novel heavy-metal complexing peptides was isolated from plant cell suspension cultures; the structure of the peptides was established as (gamma-glutamic acid-cysteine)n-glycine (n = 3 to 7). These peptides appear upon induction of plant cells with heavy metals and represent the principal metal-binding activities in the cells. The name phytochelatin is proposed for this new class of natural products.
1,181 citations
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TL;DR: In this paper, the compilation and updation of 119Sn chemical shifts (δ 119Sn) from studies on organotin compound and inorganic tin compounds, indirect nuclear spin-spin couplings, relaxation mechanisms concerning the 119Sn nucleus, and experimental details for 1I9Sn-NMR measurements are discussed.
Abstract: Publisher Summary Tin (Sn) compounds are well-recognized both in basic research and in industrial applications. Tin NMR spectroscopy includes three magnetically active tin isotopes namely, 115Sn, 117Sn , and l19Sn. However, most tin NMR parameters refer to the 119Sn nucleus owing to its properties such as abundance, magnetic moment, and NMR frequency. This chapter describes: (1) the compilation and updation of 119Sn chemical shifts (δ 119Sn) from studies on organotin compound and inorganic tin compounds, (2) indirect nuclear spin-spin couplings, (3) relaxation mechanisms concerning the 119Sn nucleus, and (4) experimental details for 1I9Sn-NMR measurements. It is observed that with modem equipment there are, in principle, no serious experimental difficulties in observing 119Sn resonances either directly or by heteronuclear double resonance. δ 119Sn data, available for all kinds of tin compounds, significantly allows using this parameter in an empirical way in order to find models for the qualitative interpretation of δ 119Sn. This also applies to couplings involving the l19Sn nucleus, which serve as a sensitive tool in the discussion of structure and bonding. All 119Sn-NMR parameters of tin compounds largely concern measurements in the liquid state.
461 citations
TL;DR: It is concluded that transfer of precursors into the inner membrane or matrix space occurs through "translocation contact sites"; precursor polypeptides to F1 beta and cytochrome c1 enter the matrix space with the amino terminus first; and a membrane potential is required for the transmembrane movement on an amino-terminal "domain-like" structure but not for completing translocation of the major part of the polyPEptides.
434 citations
412 citations
TL;DR: It is reported here that the proteins potentially encoded by four class II introns are related to several RNA-dependent polymerases of viral and transposable element origins.
Abstract: Organelle introns share several distinctive features that set them apart from their counterparts in nuclear-encoded pre-messenger RNAs (reviewed in ref 1): their termini do not obey the GUAG rule; the introns are 'structured' (members of the same family or 'class' can theoretically adopt very similar RNA secondary conformations and several of the postulated pairings have been confirmed by studies of splicing mutants and their revertants (see, for example, ref 4); many introns from both classes contain long open reading frames We report here that the proteins potentially encoded by four class II introns are related to several RNA-dependent polymerases of viral and transposable element origins
267 citations
TL;DR: Progression of the disease was most pronounced in the placebo-treated group, less so in the aspirin- treated group, and least of all in the dipyridamole-and-aspirin group.
254 citations
TL;DR: Strong two-photon photoemission is observed from Ag (111) and Cu(111) surfaces with image-potential states as intermediates and three processes are found: resonant excitation, relaxation into the intermediate state, and energy pooling via collisions between excited electrons.
Abstract: Strong two-photon photoemission is observed from Ag(111) and Cu(111) surfaces with image-potential states as intermediates. Three processes are found: (a) resonant excitation, (b) relaxation into the intermediate state, and (c) energy pooling via collisions between excited electrons. For Ag(111) we find two image-potential states with binding energies of 0.77\ifmmode\pm\else\textpm\fi{}0.03 and 0.23\ifmmode\pm\else\textpm\fi{}0.03 eV, close to the hydrogenic values, and an unidentified state 2.57\ifmmode\pm\else\textpm\fi{}0.05 eV below the vacuum level. The work function is 4.49\ifmmode\pm\else\textpm\fi{}0.02 eV.
250 citations
TL;DR: The steady-state scattering function for driven diffusive systems with a single conserved density is investigated and it is found that d = 2 is the borderline dimension with marginally nondiffusive behavior; for d larger than 2 the spread is diffusive with anisotropic long-time-tail corrections.
Abstract: The steady-state scattering function for driven diffusive systems with a single conserved density is investigated in view of the intrinsically faster, as compared to the predictions of an ordinary diffusion law, spreading of density fluctuations observed in stationary driven diffusive systems at low dimensionality, and, consequently, the divergence of excess noise for small frequencies. It is found that d = 2 is the borderline dimension with marginally nondiffusive behavior; for d larger than 2 the spread is diffusive with anisotropic long-time-tail corrections. The derivations presented are confirmed by Monte Carlo simulation results for a driven hard-core lattice gas.
234 citations
TL;DR: The polypeptide architecture of spiny lobster hemocyanin appears to be the same in all arthropods, and this structure must be at least as old as the estimated time of divergence of crustaceans and chelicerates, about 540 to 600 million years ago.
Abstract: Hemocyanins are large multi-subunit copper proteins that transport oxygen in many arthropods and molluscs Comparison of the amino acid sequence data for seven different subunits of arthropod hemocyanins from crustaceans and chelicerates shows many highly conserved residues and extensive regions of near identity This correspondence can be matched closely with the three domain structure established by x-ray crystallography for spiny lobster hemocyanin The degree of identity is particularly striking in the second domain of the subunit that contains the six histidines which ligate the two oxygen-binding copper atoms The polypeptide architecture of spiny lobster hemocyanin appears to be the same in all arthropods This structure must therefore be at least as old as the estimated time of divergence of crustaceans and chelicerates, about 540 to 600 million years ago
227 citations
TL;DR: The glomeruli and the distal part of the nephron are identified as specific targets of ANF and particulate guanylate cyclase is implicated as the enzyme targetted for the expression of its action and the results obtained in the absence or presence of a phosphodiesterase inhibitor support the notion that the effects of AnF were exerted at the level of guanylated cyclase stimulation rather than cGMP phosphodiestersterase inhibition.
225 citations
TL;DR: The productivity numbers of compounds synthesized by the methods described in this review are often 10- to 100-fold higher than those of substances obtained by conventional techniques.
Abstract: It has been known for many decades that chiral compounds can be obtained by stereospecific biocatalytic reduction. Further significant methodological developments in this field have, however, only been made during the past ten years; they include the application of previously unused microorganisms and electron donors, the discovery of additional substrates for the known reductases, the development of methods for regenerating reduced pyridine nucleotides, and the discovery of new reductases which were sought for specific preparative purposes. Many chiral compounds can now be synthesized by microbial hydrogenation using H2 and hydrogenase-containing microorganisms as well as by electromicrobial or electroenzymatic reduction. In the two latter methods, anaerobic or aerobic organisms are supplied with electrons from electrochemically reduced, artificial mediators, e.g., methyl viologen. Reductases that do not require pyridine nucleotides and can accept electrons directly from reduced viologens are especially useful. Two examples of this type of enzyme are described which are of preparative interest. Many cells contain methyl viologen-dependent NAD(P) reductases, a large number of which have still not been characterized. A productivity number is proposed which allows different methods of bioconversion with microorganisms to be compared. The productivity numbers of compounds synthesized by the methods described in this review are often 10- to 100-fold higher than those of substances obtained by conventional techniques.
TL;DR: Results give new evidence for autoimmunological events in dilated cardiomyopathy, which showed organ-specific and functionally active autoantibodies, which decreased the ADP/ATP exchange rate from heart mitochondria.
TL;DR: Field observations of diurnal gas exchange parameters and carbon isotope ratios in xylem-tapping mistletoes from three continents support the hypotheses that water use efficiency and carbon atom composition are related and that mistle toes which are parasitic for water are also nutrient parasites.
Abstract: Most mistletoes parasitize higher plants by tapping the xylem (a conduction tissue) of their hosts. Field observations of diurnal gas exchange parameters and carbon isotope ratios in xylem-tapping mistletoes from three continents support the hypotheses that water use efficiency and carbon isotope composition are related and that mistletoes which are parasitic for water are also nutrient parasites, differing in their water use efficiency relative to that of their hosts on the basis of host nitrogen supply in the transpiration stream.
TL;DR: According to the results it is necessary to reconsider qualitative and quantitative facets of the adenosine hypothesis of metabolic regulation of coronary blood flow, which—in its original formulation —exclusively centers on the cardiomyocyte metabolism.
Abstract: Cultured coronary endothelial cells and the coronary endothelium of isolated perfused guinea-pig hearts are characterized by a very active adenosine and adenine nucleotide metabolism. Adenosine applied to the endothelium at low concentrations is avidly metabolized and preferentially incorporated into different nucleotide pools—only a minor amount is degraded to uric acid. Physiologically, the coronary endothelium therefore functions as an impermeable metabolic barrier for interstitially or intravascularly accumulating adenosine. Only at concentrations≧10−6M adenosine can pass the endothelial barrier. As a consequence, the vasodilatory action of adenosine formed in or administered into the coronary system cannot be induced by a direct association of the nucleoside with the putative adenosine receptor of the arteriolar smooth muscle cells, but must be mediated by the endothelium. High molecular weight derivatives of adenosine, clearly confined to the coronary system, can also induce a coronary dilation. The endothelium-mediated smooth muscle relaxation is therefore obviously due to triggering of an extracellular adenosine receptor at the luminal surface of the endothelium. Since this process is accompanied by a rapid and pronounced activation of the adenylate cyclase system, the endothelial receptor conforms to an A2-type.
TL;DR: By use of a newly developed scanning low-energy electron-diffraction technique it is demonstrated that spatial self-organization in the oscillations involves a wavelike propagation of alternating bands of the two surface-structural modifications across the entire scanned area.
Abstract: Under appropriate conditions, the rate of catalytic CO oxidation on a Pt(100) surface exhibits sustained temporal oscillations which are associated with a periodic surface-structural transformation from the reconstructed (hex) to the nonreconstructed (1\ifmmode\times\else\texttimes\fi{}1) phase and back again. By use of a newly developed scanning low-energy electron-diffraction technique it is demonstrated that spatial self-organization in the oscillations involves a wavelike propagation of alternating bands of the two surface-structural modifications across the entire scanned area. These features can be modeled by numerical solution of a set of coupled differential equations.
TL;DR: In this paper, the authors studied the effect of phonon interactions on dissociative adsorption and associative desorption of H2 and D2 on Ni(110) and Ni(111) surfaces.
TL;DR: The centric coordination of the metal to the arene can be explained by the perfect agreement between the HOMO/LUMO symmetry of the isne and of the low-valent metal as discussed by the authors.
Abstract: Arene complexes of main-group metals were, until recently, rare species—in contrast to the now classical, analogous complexes of transition metals. In systematic investigations, it has been possible to prepare and structurally characterize arene complexes of the univalent elements gallium, indium, and thallium, which directly follow the d-block elements in the periodic table. This new type of compound is characterized by centric (η6) coordination of the metal to the arene; both mono- and bis(arene) complexes are known. The interaction can be explained by the perfect agreement between the HOMO/LUMO symmetry of the arene and of the low-valent metal. The electronic states of the nd10(n + 1)s2 configuration, which are partially modified by relativistic effects, play a particularly important role. The relationship to the few known complexes of the neighboring elements (SnII, PbII) becomes plausible via the isoelectronic principle. The arene/GaI, InI, TlI systems are of potential significance as homogeneous reducing agents and as agents for the activation of aromatic compounds, the purification of metals, and the separation of metals from nonaqueous media.
TL;DR: A new LEED intensity analysis of the reconstructed Au(110)-(1×2) surface results in a modification of the missing row model with considerable distortions which are at least three layers deep.
TL;DR: The results show that the different water use “strategies” of C3 and C4 plants are responsible for the measured difference in deuterium-isotope composition of leaf water.
Abstract: The natural abundance hydrogen-isotope composition of leaf water (\(\delta _{\text{D}}^{{\text{H}}_{\text{2}} {\text{O}}} \)) and leaf organic matter (δDorg) was measured in leaves of C3 and C4 dicotyledons and monocotyledons. The \(\delta _{\text{D}}^{{\text{H}}_{\text{2}} {\text{O}}} \) value of leaf water showed a marked diurnal variation, greatest enrichment being observed about midday. However, this variation was greater in the more slowly transpiring C4 plants than in C3 plants under comparable environmental conditions. A model based on analogies with a constant feed pan of evaporating water was developed and the difference between C3 and C4 plants expressed in terms of either differences in kinetic enrichment or different leaf morphology. Microclimatic and morphological features of the leaves which may be associated with this factor are discussed. There was no daily excursion in the δDorg value in leaves of either C3 or C4 plants. When δDorg values were referenced to the mean \(\delta _{\text{D}}^{{\text{H}}_{\text{2}} {\text{O}}} \) values during the period of active photosynthesis, the discrimination against deuterium during photosynthetic metabolism (ΔD) was greater in C3 plants (-117 to -121‰) than in C4 plants (-86 to -109‰).
TL;DR: The results demonstrate that the inner membrane of the chloroplast envelope plays a key role in chloroplow biogenesis, and especially for the synthesis of the two major plastid prenylquinones.
TL;DR: Cytochrome bc2 complex Inhibitor Fe2S2 protein EPR Cytochrome b Stigmatellin
TL;DR: A substantial escape of plasma cortisol from dexamethasone suppression was observed and ACTH responses changed in concordance with those of cortisol indicating that the LVP-CRF interaction takes place at the pituitary level.
TL;DR: After local irradiation of the rat heart with X ray doses of over 10 Gy (single dose), animals developed symptoms of radiation-induced heart disease, which at higher doses would lead to fatal cardiac failure.
Abstract: After local irradiation of the rat heart with X ray doses of over 10 Gy (single dose), animals developed symptoms of radiation-induced heart disease, which at higher doses would lead to fatal cardiac failure. The LD 50 at 1 year was between 15 Gy and 20 Gy. The pericardium and epicardium responded to irradiation with exudative pericarditis after 4 months. Focal myocardial damage was secondary to progressive capillary damage.
TL;DR: To quantitate visual findings in lymphoscintigraphy with 99mTc-labeled stannous sulfur colloids, a numeric index of transport kinetics was designed by combining visual assessment of five criteria: temporal and spatial distribution of the radionuclide, appearance time of lymph nodes, and graded visualization of lymph node and vessels.
Abstract: To quantitate visual findings in lymphoscintigraphy with 99mTc-labeled stannous sulfur colloids, a numeric index of transport kinetics was designed by combining visual assessment of five criteria: temporal and spatial distribution of the radionuclide, appearance time of lymph nodes, and graded visualization of lymph nodes and vessels. For assessment, scores were used ranging from 0 to 9. Thus, the resulting transport index (TI) ranged from 0 (normal) to 45 (pathological). TI in healthy extremities was less than 10.
TL;DR: The results, reported here, show that the energy detection properties of both foveal and peripheral vision are comparable, however, independently of scale, peripheral vision ignores the relative position of image components.
Abstract: Objects in peripheral vision are not simply blurred but lack quality of form. Assuming that the visual system performs a (patchwise) Fourier analysis of the retinal image (for review see ref. 2), it has been suggested that this disadvantage of peripheral vision may be due to the inability to encode properly spatial phase relationships. This is of great interest for neurological research as certain visual pathologies imply alterations of perceived form. Previous attempts at measuring phase sensitivities failed to distinguish between the detection of phase-related changes in contrast and phase coding in the visual system. We separated these processing strategies by applying the iso-second-order texture paradigm of Julesz to the discrimination of compound gratings. Our results, reported here, show that the energy detection properties of both foveal and peripheral vision are comparable, however, independently of scale, peripheral vision ignores the relative position of image components.
TL;DR: In this paper, the existence of nuclear effects at large Q 2 was confirmed with improved systematic accuracy by using deep inelastic muon scattering with deuterium, nitrogen, and iron targets.
TL;DR: It is suggested that cyclic GMP is a biological marker for circulating ANF in man and in plasma cyclicGMP levels in plasma and urine of eight normal men after a bolus injection of synthetic human atrial natriuretic factor.
Abstract: We studied the effects of a bolus injection of 50/Ug synthetic human atrial natriuretic factor (ANF) on the cyclic GMP and cyclic AMP levels in plasma and urine of eight normal men. Administration of the hormone increased basal immunoreactive (IR-)ANF levels in plasma 2.8-fold to 110 pM three minutes after injection. Thereafter, IR-ANF levels rapidly declined to basal levels. Plasma cyclic GMP levels increased 2.6-fold to 16.6 nM within 6 minutes after ANF and decreased to near basal values within 30 minutes. Urinary cyclic GMP excretion increased 2.8-fold, whereas urinary volume and sodium excretion increased less than two-fold in the 30 minutes after ANF. Plasma cyclic AMP levels did not change. The data indicate that changes in plasma IR-ANF levels are followed by changes inplasma cyclic GMP and in urinary cyclic GMP excretion and suggest that cyclic GMP is a biological marker for circulating ANF in man.
TL;DR: This direct approach to study tissue receptors for hGH in a human in vitro test was reproducible and should encourage the investigation of receptor regulation as well as the study of binding in human disease.
Abstract: Although specific GH receptors have been demonstrated in various tissues of a number of species, the presence of GH receptors on human peripheral mononuclear cells (PMC) is controversial. Binding of human GH (hGH) to its receptor as the hypothesized initial step of hormone action was consequently studied using mononuclear cells from peripheral venous blood of normal subjects. Specific binding of [125I]hGH was rapid, reversible, and time and temperature dependent. Specific GH binding to PMC was maximal after 8–24 h of preincubation. Binding of hormone was maximal at 37 C after incubation of cells for 2 h. Dissociation of GH was maximal at 37 C after the addition of 6 M NaCl. A linear relationship between specific GH binding and cell number was found. Saturation of GH binding to 106 PMC was obtained with 25 ng iodinated hormones. Halfmaximal inhibition of GH binding occurred at 12–25 ng unlabeled hGH/tube. Hypothalamic and pituitary hormones as well as insulin did not interfere with specific hGH binding to ...
01 Apr 1985-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, the first operative silicon drift detectors for position and energy measurements are presented, and design criteria and experimental results in the laboratory and on an accelerator beam are reported, respectively.
Abstract: Semiconductor drift chambers have been recently suggested and feasibility tests performed. This paper presents the first operative silicon drift detectors for position and energy measurements. Design criteria and experimental results in the laboratory and on an accelerator beam are reported.