Showing papers by "University of Münster published in 1982"

Structure, biosynthesis and functions of glycoprotein glycans

Abstract: Since the pioneering work on structure and function of heteroglycans compiled in the classical books edited by A. Gottschalk in 19721, there have been several promising developments in glycoconjugate research, as reviewed in this article.

Covalent crosslinking between molecules of type I and type III collagen. The involvement of the N-terminal, nonhelical regions of the alpha 1 (I) and alpha 1 (III) chains in the formation of intermolecular crosslinks.

Abstract: Several peptides containing intermolecular crosslinks were isolated from tryptic digests of the insoluble matrix of human leiomyoma and calf aorta. From leiomyoma type III collagen, two crosslinked peptides were isolated. The peptide [TN(III)]2, is a dimer which contains the 73 amino-terminal residues of two, zero-D staggered, crosslinked α1(III) chains (D being the distance by which molecules or chains are staggered relative to each other). After de-blocking with pyroglutamate aminopeptidase, its amino-terminal amino acid sequence was determined to be < Glu-Tyr-Asp-Ser-Tyr-Asp-Val-Xaa-Ser-Gly-Val-Ala-Val-Gly-Gly-Leu-Ala-Gly-Tyr-Hyp-Gly-. The involvement of [TN(III)]2 in the formation of 4D-staggered intermolecular bonds was demonstrated by sequence analysis of [TN(III)2]×T(III). For this three-chained peptide, a double sequence which corresponded to TN(III) and T(III), a nine-residue peptide from the carboxy-terminal helical crosslinking site of type III collagen, was found. Crosslinks between type I and type III collagens were identified by isolating a peptide TN(III)×TN(I) from leiomyoma. This peptide was characterized, first by digesting it with collagenase giving rise to ColN(III)×ColN(I) and then chymotrypsin giving C(III) and C(I). C(I) and C(III) are peptides characteristic for type I and type III collagens, respectively. Further, three-component crosslink-containing peptides, from both type I and type III collagen, were isolated from aorta and leiomyoma. The peptides ColN(III)× ColN(I)× T(III) from leiomyoma and Col×N(III) ColN(I)× T(I) from aorta are crosslinked amino-terminal regions of 0D-staggered type I and type III molecules, joined either to an adjacent 4D-staggered type III or type I molecule. Crosslinked peptides involving only type III collagen molecules were also isolated from calf aorta [colN(III)]2 and [CoIN(III)2]×T(III)]. As intramolecular bonds between type I and III collagens can be excluded the isolation of these crosslinked peptides demonstrated that type I and type III collagen molecules are present within the same collagen fibrit with OD stagger, bound by intermolecular crosslinks. The significance of these findings with respect to the proposed models for collagen fibres and the physiological properties of the extracellular matrix, are discussed.

Lysosomal Enzyme Precursors in Human Fibroblasts

Abstract: Precursors of cathepsin D and β-hexosaminidase were isolated from secretions of human fibroblasts and their activity was studied with natural substrates. The immunoprecipitated precursor of cathepsin D, Mr 53000, was inactive with radioactive hemoglobin as substrate. At pH 3.8–4.2 an activation of the precursor took place, which was correlated by a reduction in size to Mr 51 500. The observed cleavage of cathepsin D precursor in vitro resembles the autocatalytic activation of pepsinogen. The precursor of β-hexosaminidase A is able to cleave the natural substrate GM2 ganglioside. This reaction, like that of the mature enzyme, depends on the presence of a protein activator, which interacts with the substrate and the enzyme.

Morphological studies on the epiphyseal growth plate combined with biochemical and X-ray microprobe analyses

Abstract: The epiphyseal growth plate of the domestic pig was investigated topologically combining biochemical methods with electron microprobe microanalyses both correlated to histological controls. A lateral resolution of about 50 μm was reached. Highest nuclease activity was found in the lower columnar cell zone, while alkaline phosphatase showed maximal activity in the hypertrophic area, connected with maximal values for extractable, organically bound phosphorus, and extractable Ca and Mg. Acid phosphatase activity reached maximal values in the zone of the lower primary spongiosa, while the extractable Pi had maximal values at the end of the zone of bone remodelling. Microprobe analyses have shown that the extracellular Ca content (per dry mass) remained relatively constant at 0.7% (about 58 mM/kg wet weight for 66% tissue fluid) in all zones of the plate increasing to 1% in the vicinity of the first foci of mineralization. The intracellular P content (per dry mass) was about 4.5%, the extracellular 0.1–0.2% (about 10–20 mM/kg wet weight) increasing also to about 1% in the vicinity of the first foci of mineralization. Thus the Ca x P product was much higher than the ion-product of 2 mM2 which is necessary for an in vitro mineralization of connective tissue. The extracellular S content (per dry mass) as a probable indicator of sulfated proteoglycans was relatively constant at about 3.5% in the different zones but decreased to about 0.3% in the fully mineralized regions. This indicates a loss of sulfur containing substances with mineralization which is not so high since the concentrations per dry mass must be normalized to a unit volume of equal density of mass.

Direct structural localization of two toxin-recognition sites on an ACh receptor protein.

Abstract: One of the most actively studied chemoreceptors is the acetylcholine receptor (AChR) in the postsynaptic membranes of neuromuscular junctions and electrocytes. The AChR from Torpedo is a membrane protein, each molecule comprising five polypeptide chains1,2: two α-chains of molecular weight (Mr) 40,000, and three homologous chains of Mr 50,000 (β), 60,000 (γ) and 65,000 (δ). Only the α-summits seem to carry the specific recognition sites for agonists and antagonists2. As snake α-neurotoxins seem to bind highly specifically and quasi-irreversibly to these sites we performed a structural analysis to localize the α-subunits, using as marker native α-bungarotoxin (α-BTX, Mr 8,000; ref. 3). We report here the results obtained at 20 A resolution by electron microscopy and single-particle image averaging4, which reveal two well-defined regions within the AChR structure5,6 where the mass increases significantly on binding of α-BTX. One of these (α1) is adjacent to the region where the δ-subunit has been located6; the second region (α2) is diametrically across the molecule, ∼50 A away from the δ-subunit and also from (α1). The topography revealed by direct structural analysis can explain the results of previous nearest-neighbour cross-linking studies2,7.

The4He(12C, γ)16O reaction at stellar energies

Abstract: The capture reaction4He(12C, γ)16O (E cm= 134–338 MeV) as well as the elastic scattering process4He(12C,12C)4He (E cm=144–338 MeV) have been investigated with the use of an intense12C beam and a windowless and4He recirculating gas target system The measurements involved two large NaI(T1) crystals in close geometry to an extended gas target, whereby angle-integrated γ-ray yields were obtained A large area plastic detector was used for the suppression of time-independent background A search for cascade γ-ray transitions was carried out by coincidence techniques The measurement of absolute cross sections is also reported Theoretical fits of the excitation function for the groundstate γ-ray transition requireE1 as well asE2 capture amplitudes, which are of equal importance at stellar energies This result increases significantly the stellar burning rate of4He(12C, γ)16O and leads to16O as the dominant product at the end of helium burning in massive stars The observed capture yield to the 692 MeV state is dominated by the direct capture mechanism and plays a small role at stellar energies

The3He(α,γ)7Be reaction and the solar neutrino problem

Abstract: The capture reaction3He(α,γ)7Be has been investigated in the energy range ofEc.m. =107 to 1,266 keV. The4He or3He beams of up to 300 μA particle current were incident on3He or4He gas targets, respectively. The gas target systems were all of the windowless and recirculating type. Excitation functions have been obtained with the use of an extended-static gas target, while the measurements ofγ-ray angular distributions involved a quasi-point supersonic jet system. The determination of absolute cross sections has been carried out with both types of gas target systems. Theγ-ray yields in the3He(α,γ)7Be reaction were detected using 80 cm3 Ge(Li) detectors. The data lead to a zero-energy intercept of the astrophysicalS(E) factor ofS(0)=0.30±0.03 keV-b. This result reduces the calculated solar neutrino rate by a factor of 1.76.

PO2-profiles in hippocampal slices of the guinea pig.

Abstract: For a detailed analysis of the oxygen supply of hippocampal slices, tissue PO2 (Pt,o 2) was recorded polarographically in the neural layers of thick and thin slice preparations from the guinea pig. The experiments showed that the Pt,o2-gradients were extremely steep in the outer zones of vital slices. In an air equilibrated salt solution the surface PO2 was reduced to less than 50% within ca. 25 μm. Minimum values were measured at a depth of ca. 150 μm. A rise of temperature lowered the oxygen supply in the deeper layers of the excised tissue. An elevation of the surface PO2 hardly improved Pt,o 2 in the deep structures, because the O2-consumption of the hippocampal slices increased with rising PO2.

Enhanced Breakdown of Arylsulfatase A in Multiple Sulfatase Deficiency

Abstract: Multiple sulfatase deficiency (mucosulfatidosis) is a lysosomal storage disorder characterized by the decrease in activities of all known sulfatases. To measure the apparent rate of synthesis and the half-life of arylsulfatase A in multiple sulfatase deficiency, fibroblasts from patients with the disease and from controls were subjected to pulse-chase labelling with radioactive amino acids. Arylsulfatase A and cathepsin D, a lysosomal enzyme that is not affected in multiple sulfatase deficiency, were isolated from cells and media by immunoprecipitation. The labelled polypeptides were separated by polyacrylamide gel electrophoresis, visualized by fluorography and quantified by liquid scintillation counting. Using single and double isotope techniques it was found that, as compared to cathepsin D, the apparent rate of synthesis of arylsulfatase A was 2–5-times lower and the half- life 4–9-times shorter in multiple sulfatase deficiency than in control fibroblasts. In multiple sulfatase deficiency fibroblasts the rates of endocytosis and the stabilities of endocytosed arylsulfatases A isolated from human urine and bovine testes were equal to those in metachromatic leucodystrophy fibroblasts. We postulate that in normal cells a gene product exists that affects the stability of sulfatases and that multiple sulfatase deficiency is due to a mutation in this gene.

Radiation defects in feldspars

Abstract: Various radiation defects were characterized and analyzed by electron paramagnetic resonance (EPR) in 15 feldspars of different compositions after X-ray irradiation. A hole center on oxygen adjacent to two aluminum ions is formed in most feldspars, except those with very high An content. Since the hole is not localized at room temperature, clusters of more than two Al must be present in all feldspars in amounts of at least 100 ppm. Less frequent radiation defects are trivalent titanium and holes on oxygen ions adjacent to a small divalent ion of a yet unidentified nature on a T site with Si and in some cases also Pb as further neighbors. The directions of the magnetic axes for these centers allowed their assignment to specific sites in the feldspar structure. Characteristic absorption and thermolu-minescence emission bands could also be assigned to these centers. Their properties are remarkably independent of composition and Al, Si disorder of the feldspars.

Theory and physical importance of integrated state multipoles

Abstract: We consider the polarisation properties of light emitted by heavy atoms after excitation by polarised electrons. It is discussed what information on spin-dependent forces can be obtained from the measurements.

Apolipoprotein A-IV polymorphism in man.

Abstract: In man, apolipoprotein A-IV is characterized by a genetically determined polymorphism controlled by two codominant alleles. Two isoforms of this apolipoprotein, designated A-IV-1 and A-IV-2, can be identified by isoelectric focusing. Among 1000 healthy factory workers participating in an epidemiological study, A-IV-1 (genotype 1-1) was observed in 85%; A-IV-2 (genotype 2-2), in 0.5%; and A-IV-1 in combination with A-IV-2 (genotype 1–2), in 14%. In four nonrelated subjects, an apolipoprotein A-IV variant (A-IV-Munster), characterized by a slightly more basic isoelectric focusing behavior than A-IV-2, was detected in combination either with A-IV-1 or A-IV-2. Mendelian inheritance of this variant could be demonstrated.

Structure of the Octabismuth(2+) Cluster in Crystalline Bi8(AlCl4)2

Abstract: The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 1108. DOI:10.1002/anie.198211080

Interferon inhibits the suppressor T cell response of delayed-type hypersensitivity.

Abstract: We have recently shown that pretreatment of BALB/c mice with Corynebacterium parvum preferentially inhibits suppressor T lymphocytes (Ts) which have been induced by an epicutaneous antigen overload1 or by intravenous (i.v.) injection of 2,4-dinitrobenzenesulphonic acid (DNBSO3)2. Serum obtained 24 h after C. parvum injection had a similar suppressive effect on Ts but no effect on T effector lymphocytes of delayed-type hypersensitivity (TDH)3 Inhibition of Ts by this serum could be neutralized by an anti-interferon globulin4. A crude mouse fibroblast interferon (IFN) preparation also inhibited the Ts response4, which suggested that IFN in C. parvum serum might be the Ts inhibitory factor. We have now studied the effect of an electrophoretically purified mouse interferon (IFN-α and β) preparation on the Ts response to dinitrofluorobenzene (DNFB) in BALB/c mice. Small amounts (1,000 U) of the preparation inhibited the generation of Ts by DNBSO3 in vivo, and the function of Ts both in the recipient animals when injected i.v. 2 h after transfer of the Ts and after incubation of the spleen ceUs from tolerant animals with interferon before transfer into recipients. The TDH response was not affected by this amount of interferon.

The 15 N( p , α 0 ) 12 C reaction at stellar energies

Abstract: The15N(ρ, α0)12C reaction has been investigated in the energy range ofE p (lab)=78-810keV. The measurement of the excitation functions and α-particle angular distributions involved solid targets as well as a quasi-point supersonic jet gas target. The determination of absolute cross sections has been carried out with the gas target. The observed energy dependence of the total cross sections can be described in terms of two-level Breit-Wigner shapes including the resonances atE p (J π)=335(1−) and 1,028(1−)keV. The data lead to a zero-energy intercept of the astrophysicalS(E) factor ofS(0)= 65±4MeV-b. The angular distributions are asymmetric around 90° and require an additional amplitude in the reaction mechanism, which interferes predominantly with the 335 keV resonance. The origin of this background amplitude is discussed.

Formation of gluconic acid at low pH-values by free and immobilized Aspergillus niger cells during citric acid fermentation

Abstract: A recently developed immobilization method, characterized by the adsorption of the mycelia onto a glass-carrier in a fixed-bed reactor, was applied for citric acid production by Aspergillus niger ATCC 9142, and compared with conventional culture techniques.

What is magic about the magical number four

Abstract: Previous studies have shown that the apprehension of number can be represented by three models according to the experimental procedure and the data analysis. The present experiment was designed to test the effect of figural characteristics of pattern on the response time. The subjects were asked to perform a same/different judgment, i.e., they were requested to decide whether a dot pattern, shown on a monitor, equalled a previously defined target number (n=2–6) or not. Different ‘types’ of pattern were used and learning effects were studied. As was expected, the slopes for random and linear patterns were not so steep when the target number was low. With patterns in the dice mode, however, the slope was zero. Repeated presentations led to a slight reduction in slope for random and linear patterns only. In the case of the patterns in the dice mode, the repeated presentations caused only a change in the absolute reaction times (RTs) but had no effect on the slope. When the target numbers were larger (n=5–6), the repeated presentations led to remarkable reductions in slope for random and linear patterns. The slope discontinuity at n=4 occurred with all ‘types’ of pattern but it became less pronounced in the course of training at least in the case of random and linear patterns. This result is explained by clustering effects, use of figural cues, and a more efficient scanning process.

Cutaneous sensitivity to ultraviolett light and chemical irritants

Abstract: This investigation examines the relationship between the sun sensitivity of human skin and its response to chemical irritants. Forty-four Caucasoid subjects with normal back skin were studied. The minimal erythema dose (MED) was determined with the sunburning spectrum of a high-pressure mercury lamp. Cutaneous irritability was quantified using a series of seven irritants of different chemical structure, solubility, and concentrations. The response was either expressed as a threshold value of exposure time (ammonium hydroxide, sodium hydroxide) or was graded after a standard exposure in intensity of whealing (dimethyl sulphoxide) or erythema (sodium lauryl sulphate, quaternium 1, croton oil, kerosene). A significant correlation between the MED and the response to all seven primary irritants was found. The relationship was better for water-soluble irritants than for lipid-soluble ones. Despite marked individual variations the determination of the MED is suggested as a valuable tool in identifying hyperirritable skin. Skin typing based on complexion and sunburn history proved to be less reliable.

Quantitative succinic dehydrogenases histochemistry. A comparison of different tetrazolium salts.

Abstract: Activity of succinic dehydrogenase (SD, EC 1.3.99.1) was investigated in the livers of 17 male albino rats by means of the tetrazolium salts NBT, INT, MTT, BT and TT, incubations carried out at a determined pH optimum of 7.9 and activities calculated with regard to activity of “nothing dehydrogenase” (ND) measured in control sections incubated without substrate. The highest activity could be achieved by means of NBT, the ratios of activities measured by NBT, INT, MTT, BT and TT being 100:86:82:29:18 and the order of activities corresponding to the order of redox potentials of the tetrazoles. A determination of ND was necessary, because of its influence on the real activity of SD measured in the slices by means of NBT, INT and MTT. Exact measurements could be made if activity was related to the dry weight of the slices or to the content of nucleic acid — bound phosphorus of reference slices; if activity was related to the content of protein of reference slices, the standard deviation would be the 1.4 fold. Meldola Blue (MB) was not a suitable soluble redox dye, the use of it leading to an activity only 23% of that determined when phenazine methosulphate (PMS) applied. A special measuring of the half-formazan of NBT, the molar extinction coefficient determined being 21,840 l/Mol/cm, produced higher accuracy of measurement, but had no influence on the amount of activity of SD. A comparison of the measured activity with reference values obtained by biochemical methods and histochemically quantified with PMS applied, showed a good conformity.