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  • ZIB Katalog
  • Artikel: DFG Deutsche Nationallizenzen  (201)
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  • Life Sciences  (201)
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  • Artikel: DFG Deutsche Nationallizenzen  (201)
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  • 1980-1984  (53)
  • 1975-1979  (148)
  • 1950-1954
  • 1945-1949
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  • 1
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 365-370 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A schematic representation of the variety of products which can be obtained by microbial conversion of cellulose is presented.Alkaline pre-treatment has been used after milling in all the experiments. Solka-floc or sugarcane bagasse was used as sources of cellulose. A cellulolytic strain of Aspergillus terreus (ATCC 30514) was cultivated in batch-, fed batch and continuous culture up to 7 liter stirred tank fermenter. The general growth characteristics were determined by growing on glucose. Results of experiments on the growth of A. terreus for production of biomass on Solka-floc or Sugarcane bagasse are given, also the ability of crude cellulases to produce sugar syrups by enzymatic hydrolysis of cellulose has been evaluated.
    Zusätzliches Material: 5 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 207-246 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 247-267 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Examination show how far the stirred tank fermenter meets the requirements of multi-phase systems under conditions of microbiological protein synthesis. 1The homogeneity attained by mixing of 4-phase-fermentation medium will be influenced by different amounts of material flow of the correspondent process conditions.2Limitation of nitrogen and solved nutrient - and trace salts in culture liquid by unsatisfactorily mixing can be excluded. The solute-oxygen concentration and homogeneous distribution of solute-oxygen in the culture liquid are influencing the economy of fermentation.3The homogeneity concerning petroleum distillate-, biomass-and air distribution highly depends from biomass content of the fermentation medium.
    Zusätzliches Material: 21 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 279-284 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Lipids were extracted from the cells of Lodderomyces elongisporus EH 15 grown on gas oil (Bp. 240 to 360 °C) with benzine/alcohol (80:20). The lipid-hydrocarbon-fraction obtained by this extraction method was 18.5%. It was composed of hydrocarbons, phospholipids, fatty acids, glycerides, sterols, ubiquinones, and vitamines. The main components among the lipids were phospholipids. The compositions of phospholipid, fatty acid, sterol, and ubiquinone fractions were analysed.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A brief review of the most important properties and fields of application of microbial proteinases are presented. Special possibilities of an industrial utilization of these enzymes are discussed: in the photographic industry for the production and degradation of gelatin as well as for silverless photography, in the food industry for the improvement of the functional properties of proteins as well as for increasing their nutritive value, in organic synthesis for the production of peptides, and in sewage treatment plants for the stabilization of sludge.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The influence of the carbon substrates glucose and methanol on enzyme activities of the yeast Candida methylica was investigated by substrate-shift experiments in discontinuous cultivation. Growth on glucose results in a repression of the enzymes necessary for methanol utilization. After depletion of glucose or addition of methanol these enzymes are derepressed or induced, respectively. Changes in the activity of enzymes of the intermediary metabolism turn out differently both in intensity and direction as a result of substrate-shifts. The results suggest a basic change in the metabolism by growing Candida methylica in glucose or methanol.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 191-195 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract in Russian.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 201-204 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 11
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Coordinated regulation of carbon and energetic metabolism enzymes is characteristic of lysine producing strains of Brevibacterium flavum. ATP is the regulating effector and changes in the stationary ATP-concentration in cells cause certain alternations of enzyme activities in the basic metabolism pathways. The goal of the experiments was the use of the biochemical regulations of methabolism in order to increase the productivity of lysine biosynthesis.Following results were received: Activation of TCA-cycle enzymes is compulsory for intensive lysine biosynthesis.The most essential of several parallel electron transport pathways in the ETC of Br. flavum is the NADH dependent, cyanid resistant, hydroxamate sensitive oxydation pathway.Calculations have shown, that the most economical variant is the synthesis of oxalacetate (precursor of lysine) by PEP carboxylation. Therefore strains with elevated PEP-carboxylase activity synthesize lysine in a more economical way.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 391-392 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: No Abstrct.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 13
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 131-137 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The propagation of the virulent phage M 1 of the obligate methylotrophic bacteria strain GB 4 is inhibited by n-alkanes. The addition of hydrocarbons (7.5-22.5%) to a suspension of free phages or to a phage-host-mixture prevents the propagation of the phages, but does not influence the growth rate of the host bacteria. In a laboratory fermentor a simulated strong infection (multiplicity = 0.1) of the strain GB 4 with its phage M 1 could be suppressed by the application of 20% of a technical hydrocarbon mixture (Parex I).The inhibitory effect of the hydrocarbons can be traced back to inspecific hydrocarbon-protein-interactions at the surface of the phage and the host cells and therewith to an influencing of the adsorption.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 14
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 139-143 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The influence of microorganisms growing on the walls of laboratory fermenters was investigated and a model to describe of microbial lysis and the formation of growth inhibitory products in a continuous fermentation process was developed.The predictions were compared with results from an earlier model for growth of microorganisms on surfaces.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 296-299 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: An automatic eightfold-pipetter has been developed with the same basic unit as the diluter of the Autoselect-system. The pipetter is fitted with eight pipettes on a bridge over the basic unit. By means of the pipettes a volume of 0.05 ml from eight tubes is exhauseted and delivered in the holes of a test plate. Both the test plate and a cassette with 64 tubes are located on a moving carriage. the test plate on the first floor and the cassette on the ground floor. If the pipettes transfer the samples from the tubes to the holes the distance between the pipettes must be changed by a special device from 20 to 30 mm, because the distance between the holes on the test plate differs from that of the tubes.For the transfer of 64 samples 2 minutes only are needed.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 16
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 304-307 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 17
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981) 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 18
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 326-326 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 19
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 338-338 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 20
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 339-350 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Microbial cells were gel-entrapped with photo-crosslinkable resin prepolymers or urethane prepolymers, respectively. The resulting gels have different tailor-made hydrophobic or hydrophilic character. They were used for successful bioconversion of hydrophobic steroids and terpenoids in watersaturated mixtures of organic solvents. The experiments show the influence of the hydrophobicity of the gels and the polarity of the solvent mixtures, respectively. Use of hydrophobic gels and less polar solvents is preferable for bioconversion of hydrophobic compounds. The selective formation of a desired product among diverse products from a single substrate by appropriate use of hydrophobic or hydrophilic gels is possible. In each case, tests should be made to select the appropriate gel and solvent mixture. Bioconversions tested are: dehydroepiandrosterone to 4-androstene-3,17-dione; cholesterol to cholestenone; β-sitosterol to β-sitostenone; stigmasterol to stigmastenone; pregnenolone to progesterone; testosterone to Δ1-dehydrotestosterone or 4-androstene-3,17-dione, respectively; all with immobilized cells of Nocardia rhodocrous; and stereoselective hydrolysis of dl-menthyl-succinate to yield l-menthol with immobilized cells of Rhodotorula minuta var. texensis.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 21
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 300-303 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: An eightfold punch belonging to the Aùtoselect-system is described. It is provided for the preparation of bioassay plates. From the agar of large quadratic test plates moving automatically on a carriage of the machine, 64 holes are made by eight punches. The punches arranged in a row over the test plate are lowered, if the carriage stops, and so they cut out and exhaust agar discs in a pattern of 8 × 8.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 22
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: No Abstarct.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 23
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 311-325 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Starting with the definition of the process term kLa, steady state and nonsteady state measuring methods are described for its determination. Then the sorption characteristics for mixing vessels and for bubble columns are presented with respect to the coalescence behaviour of the system treated. They permit the scale-up of these devices and the optimization of their process parameters for a required oxygen uptake. In addition to the sorption characteristics for the given system the knowledge of the flooding point and the power characteristics is necessary for the lay-out of mixing vessels, whereas in the case of bubble columns the gas hold-up characteristic needs to be known.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 24
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981) 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 25
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 3-8 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Auf der Basis der Flotationstheorie der festen Partikel wurde in der Submerskultur der Mechanismus des direkten Sauerstoffübergangs in die Zelle unter den Bedingungen gegenseitiger Beeinflussung des Mikroorganismus mit der gasförmigen und der flüssigen Phase quantifiziert.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 26
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 17-29 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Aus Fermentationen mit Bacillus subtilis, die zum Zwecke der Synthese extrazellulä rer Enzyme angesetzt wurden, konnten verschiedentlich Bakteriophagen isoliert werden. Die auf Grund der Wirtsbereiche differierenden Einzelplaqueisolate wurden elektronenmikroskopisch untersucht. Die Partikel waren sehr verschieden in der Größe und in der morphologischen Struktur. Sie gehörten damit verschiedenen Gruppen von Bacillus-Phagen an, die durch die Standardphagen SPO1, Ø29 und PBS1 reprä sentiert werden. Außerdem wurde ein Phage mit einem oktaedrischen Kopf gefunden. Aus einem enzymbildenden Bacillus-Stamm konnten nach Infektion mit dem PBS1-ä hnlichen Phagen PZ-F Ghosts mit oktaedrischen Köpfen sowie nach Induktion mit Mitomycin C komplette und defektive Phagen freigesetzt werden.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 27
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 9-15 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The capability of the yeast Lodderomyces elongisporus to utilize solved paraffins in fermentation brothes could be demonstrated. The growth rate of this microorganism in the case of utilization of solved paraffins is higher as the most known dates.The saturated concentrations of solved hydrocarbons in the fermentation brothes are higher as in real solvent systems.The part of the solved hydrocarbon is a function of the power input, the diameter of oil drops, the fermentation conditions and the length of the paraffin chain.The organism growth rate depends on the solved paraffin concentration in the fermentation broth. This fact is one of the reasons for the variability of the consumption coefficients by utilization of paraffins with different chain lenghts.The results confirm the assumption that the transport of the paraffins from the oil drops to the cells takes place over water soluble phase.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 28
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 31-40 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Die Xylanaseproduktion durch Streptomyces xylophagus nov. sp. wurde im Schü ttelkolben und in einem 14-Liter-Laborfermentor in diskontinuierlicher und in kontinuierlicher Kultur untersucht. Die maximale Enzymausbeute wurde auf 1%igem handelsü blichen Xylanmedium bei 30°C durch 7,5%ige ü berimpfung einer 5 Tage alten Xylankultur erreicht, wobei dem Medium im Schü ttelkolben 0,8% und dem Submersfermentor 0,3% Bactopepton zugestzt wurden. Die maximale Xylanaseproduktion wurde bei pH 7,4 erreicht. Eine Hitzbehandlung bis zu 200°C wirkte sich nicht hemmend auf die Xylanaseproduktion aus.Die Gleichgewichtsparameter fü r die Zellmasse, lösliches Protein und die Xylanaseaktivitä t wurden in Abhä ngigkeit der Verdü nnungsraten von 0,02 bis 0,04 h+1 bestimmt, wobei Xylan (wood gum xylan) als Kohlenstoffquelle diente. Die maximale Enzymaktivitä t und Produktivitä t von 7,2 X.U. (1 xylanase unit, X.U. ≙ 1 mg reduzierter Zucker, der aus 1 ml Enzym in 15 Minuten bei 50°C gebildet wird) und 0,194 X.U./h wurden bei einer Verdü nnungsrate von 0,027 h+1 beobachtet.Die maximale Zellkonzentration und Produktivitä t von 7,2 g/l und 0,245 g/lh wurden bei einer Verdü nnungsrate von 0,34 h+1 beobachtet.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 41-47 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Die bei der Herstellung von OYOKPO, einem in der Bendel-Region von Nigeria traditionell auf Hirse-Basis gewonnenem Bier, wirkenden Mikroorganismen wurden untersucht.Die Ergebnisse zeigen zwei Phasen der Einwirkung unterschiedlicher Mikroorganismen.Fü r die saccharolytischen Aktivitä ten beim Mä lzprozeβ sind die aus den gelagerten Hirsekörnern stammenden Mikroorganismen (im Zusammenwirken mit der pflanzlichen Amylase des Hirsemalzes) verantwortlich. Sie werden wahrscheinlich beim Erhitzungsprozeß abgetötet.Die im fermentierten Produkt gefundenen Mikroorganismen stammen aus der fü r die Fermentation eingesetzten Starterkultur; sie vergä ren die niederen Zucker zu Alkohol.Schimmelpilze treten nach der Fermentation nicht mehr auf; Hefen sind wä hrend des Mä lzprozesses nicht zu finden mit Ausnahme von Saccharomyces cervisiae, sie erscheinen jedoch wä hrend der Fermentation. Veschiedene Bakterienarten sind in allen Stadien anzutreffen, so beim Mä lzen, Maischen und bei der Reifung. (Acetobacter wurde bis zu Beginn der Reifung nicht nachgewiesen.) Der pH-Wert sinkt von Beginn der Fermentation (5,2) bis zum Ende auf 3,8. Der am Ende erhaltene Sä urewert entspricht 0,43% (als Essigsä ure titriert).
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 30
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 49-56 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Auf der Grundlage von hydrodynamischen und reaktionstechnischen Voraussetzungen wird ein dreiphasiges Stoffsystem mit mikrobieller Reaktion auf quasi-homogene Modelle zurü ckgefü hrt. Mit Hilfe der Michaelis-Menten-Kinetik werden Geschwindigkeitsgleichungen fü r die auto katalytische Reaktion des wachstumsverbundenen Substratabbaues hergeleitet, die sich bis auf die Monod-Kinetik zurü hren lassen. Es wird bewiesen, daß die Geschwindigkeitsgleichungen der mikrobiellen Katalyse denen der heterogenen Gaskatalyse analog sind.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 31
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 57-65 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Growth of Methanosarcina barkeri on methanol as energy source was found to be dependent on cobalt and molybdenum. In the presence of 10-6 M Co and 5 × 10-7M Mo optimal growth occurred. Furthermore it could be demonstrated that nickel and selenium each in a concentration of 10-7 M stimulated the growth of this methanogenic bacterium while the following elements tested in the range of 10-7 M to 10-3 had no influence: B, Cr, Cu, Mn, Pb. The requirement of Co and Ni for optimal growth are in accordance with the results that the cells contain the Co containing corrinoid Factor III (0.1 - 0.2 mg 5-hydroxylbenzimidazolylcyanocobamide per g wet cells) and Factor F430, a nickel component. Studies on the vitamin dependency of M. barkeri showed that this strain needs only the vitamin riboflavin for the growth in a defined medium. Under these conditions a cell density of 2.6 g dry cells/l could be obtained in a fed batch culture.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 32
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 67-72 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 33
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 73-102 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A review is given of most of the literature concerning the immobilization of whole microbial cells and their testing for application in product synthesis. The review includes a discussion of adventages and disadventages of immobilized cells, methods of immobilization, pretreatments, aftertreatments, operation, recent developments, and other problems together with a table of the immobilized microbes and the tested reactions of product synthesis, with 350 references.
    Materialart: Digitale Medien
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  • 34
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 103-103 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 35
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981) 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 36
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 107-113 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Rheological measurements can give interesting informations for the characterization of fermentation broth, especially concerning the depending of the oxygen transfer rate. Rheological measurements can report decisions for choosing the best reactor type or other process steps e.g. purification and separation.An advantageous method was used by the combination of a dynamic process-viscosimeter with the fermenter and the continuous measurement of medium density by X-ray absorption method.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 37
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 115-126 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The problem of the rate-limiting step of heterogeneous catalytic reactions is explained. For microbiological catalysies in a highdispersial system the partial steps of substance transfer from macroscpace up to the biochemical reaction in the cell (microspace) are generally described and formulated. By means of statistical modells based on the theory of the isotope turbulence the numeric interpretation for the investigation of rate-limiting step at the fermentation and ripening of beer in bioreactors with enforced turbulence takes place. The rate-limiting step is the biochemical reaction of the extract degradation, that means kR·tH ≪ 1.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 38
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 127-130 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: On the base of measuring the respiration rate (HARRISON) a biological measuring method for determination of methanol concentration in stationary range was worked out. The method allows the determination of methanol concentrations up to 0.3 mg l-1 and is applicable for such cases, when microorganisms consume this substrate quickly (within a few minutes). If the methanol concentration in stationary range is known, it is possible to calculate the kinetic constants of the system.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 39
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 145-151 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The influence of extracellular concentrations of hydrogen ion and C-substrates on the specific growth rate of different microorganisms is investigated.A general relationship in the form \documentclass{article}\pagestyle{empty}\begin{document}$$ \mu {\rm } = {\rm }\mu _{\max } {\rm } - {\rm }K_2 \left( {c_i } \right)^{K_1 }$$ \end{document} can be used to describe the inhibition effect of HPlus;- or substrate concentration (ci) on the growth rate. Different examples are demonstrated and the adequate specific constants K1 and K2 calculated.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 40
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 153-159 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The improved method for preparing Oyokpo a Nigerian fermented beverage from millet, and the preparation of single cell proteins from the spent grain is described. Improvement of the brew was made by controlled malting, mashing and brewing with a pure culture of Saccharomyces cerevisiae. It had a reducing sugar content of 19.73 g/100 ml before fermentation and after fermentation 5.56% alcohol, 0.58 g/100 ml titratable acidity as acetic acid, a final pH of 4.2 and consisted of a yellowish clear liquid, slightly sour. The native brew had a reducing sugar content of 7.37 g/100 ml before fermentation and after fermentation, 2.40% alcohol, 0.43 g/100 ml titratable acidity, a final pH of 3.8 and consisted of a creamy yellowish liquid with a very sour taste. Fermented spent grain gave a higher protein yield compared to unfermented or ground millet. The lipids, proteins and crude fibre were 4.94%, 11.20% and 4.33% respectively for ground millet, 12,79%, 23.77% and 19.46% respectively for unfermented spent grain and 19.61%, 47.28% and 32.09% respectively for fermented spent grain. The high protein and fibre content of the fermented spent grain points to its potential as a feed supplement for ruminants.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 41
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 161-165 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract in Russian.
    Materialart: Digitale Medien
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  • 42
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The methodical principle of an automated selection system for antibiotic producers, the Autoselectsystem, consisting of six machines and a computer is explained. In order to work with this machines the following material is needed: Cassettes with 64 microculture cups for cultivation of colonies on agar, cassettes with glass-tubes for dilution of samples, and test-plates with 64 holes for performing the agar diffusion test. The cups, the tubes and holes are arranged in a pattern of 8×8. In a serie of papers the machines will be described.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 43
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 175-179 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: An agardeliverer, one of the machines of the Autoselect-system is described. This machine allows to pour melted agar automatically into a row of 8 microculture cups of a cassette with 64 cups. By changing the agarcontainer provided for one medium against another container with 8 chambers the machine offers the possibility to deliver 1 to 8 media simultaneously. In this respect the machine gets more and more interest not only for the selection of antibiotic producers, but also for taxonomic, genetic and other studies. Sterile conditions are ensured by sterilizing the head of the machine before starting the work.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 44
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: An inoculator enabling the isolation of colonies from petridishes onto agar-filled microcultur cups, arranged in a pattern of 8 × 8 in cassettes, is described. The transfer of the colonies takes place by turning of an inoculation cross with 4 loops. While the cross stops and lowers, one loop is sterilized, another, which has been sterilized shortly before, is being cooled in sterile water, the next one is taking off some material from a colony and the last is spreading the material on the agar of a cup. The capacity of the machine accounts about 600 colonies per hour.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 45
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 187-189 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 46
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981) 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 47
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 197-199 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: It was found that the cellular Na+-concentration (CcellNa+) of Lodderomyces elongisporus D is depended on the extracellular K+-concentration (CexK+).The relationship can be described by an equation in the form \documentclass{article}\pagestyle{empty}\begin{document}$$C_{{\rm cell}}^{Na + } {\rm } = {\rm const}.{\rm } - {\rm const}.{\rm } \cdot {\rm }\ln {\rm }C_{{\rm ex}}^{K + } .$$\end{document}The function of the natrium ion seem to be to support the utilisation rate of potassium ion at lower extracellular K+-concentration.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 48
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 268-268 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: No Abstarct.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 49
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 269-278 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Fundamentals of bioreactor design are the following functions: macro- and micro-mixing, mass transfer, heat exchange, bioreactor control and its scale-up. Mixing, mass transfer, heat exchange involve the determination of elementary zones of reactor, the mass transfer and the heat exchange between them and also between individual phases (liquid, gaseous, solid), including a possibility of direct gas-cell oxygen uptake. The overall description of a bioreactor is obtained by combining models of reactor hydrodynamics, mass transfer and heat exchange with a appropriate cell or population model. On the basis of hierarchical description new biological scale-up procedures (via modeling and simulation) may evolve.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 50
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 285-290 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Aldehyde oxidase from pig liver was adsorptively bound to DEAE-cellulose. The data of immobilization and the properties of the immobilized enzyme are reported. Its maximum half-life is 36 days. The pH-optimum is displaced toward lower pH-values and independent from the substrates proved. Temperature optimum and substrate specifity, however, don't change during immobilization. Contrary to the soluble enzyme the aldehyde oxidase adsorbed to DEAE-cellulose displays a two-phase ARRHENIUS plot.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 51
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 291-295 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: As a part of the Autoselect-system an eightfold diluter is described. Cassettes with 64 tubes are placed on the carriage of the machine and moved automatically in eight steps. One of the cassettes is loaded with separated samples in 64 tubes and the other one with 64 empty tubes. When the carriage stops, a defined volume of samples is exhausted by eight pipettes, mounted on a bridge spanning over the ground unit from left to right, and after beeing moved to the second cassette the pipettes deliver the samples into a row of empty tubes. At the same time by eight syringes mounted on both sides of the machine a defined volume of buffer is delivered through tubes and canules. By this way all samples can be diluted in two minutes.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 52
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The morphology of filamentous microorganisms does essentially affect the production of metabolites. Agitating conditions may affect the morphology and for this reason the production of metabolites too.The following parameters it was found to have an influence: Reynolds mixing numberimpeller blade tips velocitymean shear stress close to the impellerimpeller power consumption per unit volumecavitation pressure dropIt were presumed three mechanisms for the mechanical effect on the microorganisms: 1the direct impact of the impeller blades on the microorganisms-collision2the shear stress in the liquid phase3a sharp pressure decrease behind the impeller blades-cavitationMathematical relationships are developed for the different mechanisms.Using Aspergillus niger it is shown what morphological and physiological states of this microorganism are caused by mechanical straining and the conditions for the maximal production of citric acid are studied.Requirements for scale-up are discussed.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 53
    Digitale Medien
    Digitale Medien
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 1 (1981), S. 351-364 
    ISSN: 0138-4988
    Schlagwort(e): Life Sciences ; Life Sciences (general)
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A general view of the possibilities of producing ethanol from sugar, starch and cellulose feedstocks is given.For the 3 variants net energy analysis of ethanol production and evaluation of costs are presented. With the exception of the case using molasses as feedstock the net energy balances are positive.The greatest possible net energy yield can be expected with sugar cane followed by sugar beets, wood and paper waste. Based on feedstock availability, net energy utilization and production costs, the most promising processes for producing ethanol from non-grain feedstocks over the next 20 years will be those processes using fermentable sugars available from nongrain starchy materials, cellulosics and whey.The feedstock prices for cellulosics are low and if the developments in cellulose hydrolysis will lead to improve the ethanol yields from cellulose fermentation to nearer 90 percent of the theoretical value, cellulosic materials can become a good feedstock for ethanol production.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 54
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 307-327 
    ISSN: 0091-7419
    Schlagwort(e): fibroblasts ; plasma membranes ; contact inhibition ; growth control ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Addition of a suspension of a surface membrane enriched fraction prepared from confluent 3T3 cells to sparse 3T3 cells in culture results in a concentration dependent and saturable decrease in the rate of DNA synthesis. The inhibition of cell growth by membranes resembles the inhibition of cell growth observed at confluent cell densities by a number of criteria: (1) In both cases the cells are arrested in the G1 protion of the cell cycle; (2) the inhibition by membranes or by high local cell density can to a large extent be compensated for by raising the serum concentration or by addition of fibroblast growth factor plus dexamethasone. Membranes prepared from sparse cultures inhibit less well than membranes from confluent cultures in a manner which suggests that binding of membranes to cells is not by itself sufficient to cause inhibition of cell growth. The inhibitory activity has a subcellular distribution similar to phosphodiesterase (a plasma membrane marker) and appears to reside in one or more intrinsic membrane components. Maximally, membranes can arrest about 40% of the cell population in each cell cycle. Plasma membranes obtained from sparse 3T3 cells are less inhibitory than membranes obtained from confluent cells. This suggests either that the inhibitory component(s) in the plasma membrane responsible for growth inhibition may be in part induced by high cell density, or that this component(s) may be lost from these membranes during purification.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 55
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 327-338 
    ISSN: 0091-7419
    Schlagwort(e): AcChR-enriched membranes ; pyrenesulfonyl azide ; fluorescent probes ; photolabeling ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Acetylcholine receptor (AcChR) enriched membrane fragments from Torpedo californica electroplax were labeled by in situ photogenerated nitrenes from a hydrophobic fluorescent probe, pyrene-1-sulfonyl azide. Preferential photolabeling of membrane proteins, mainly AcChR, has been achieved and there is a pronounced exposure of the 48,000 and 55,000 molecular weight subunits of AcChR to the lipid environment of the membrane core.Covalent attachment of the photogenerated fluorescence probe does not perturb the α-neurotoxins' binding properties of membrane-bound AcChR or the desensitization kinetics induced by prolonged exposures to cholinergic agonists. Non-covalent photoproducts can be conveniently removed from labeled membrane preparations by exchange into lipid vesicles prepared from electroplax membrane lipids. Fluorescence features of model pyrene sulfonyl amide derivatives, such as fine vibrational structure of emission spectra or fluorescence lifetimes, are highly sensitive to the solvent milieu. The covalently bound probe shows similar fluorescence properties in situ. PySA photoproducts have great potential to spectroscopically monitor neurotransmitter induced events on selected AcChR subunits exposed to the hydrophobic environment of membranes.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 56
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 1-14 
    ISSN: 0091-7419
    Schlagwort(e): myosin ; Dictyostelium ; RNA ; motility ; nonmuscle cells ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Myosin purified from Dictyostelium amoebae has approximately 10% by weight of RNA associated with it, unless specific steps (DEAE cellulose chromatography or R Nase digestion) are taken to remove it. This RNA has significant effects on the structural states formed by the myosin at low ionic strength in the presence of Mg2+.Rapid precipitation of Rna-free myosin by dilution generates bipolar thick filaments (540 nm long, 33 nm thick), often with a bare zone and a 15-nm transverse repeat. Rapid precipitation of myosin with copurified RNA yields linear aggregates of bipolar filaments, showing some lateral association.Slow precipitation of RNA-free myosin by dialysis yields very long filaments or ribbons (〉5 μm, 30-60 nm wide) in which the myosin may be packed diagonally across the filament, similar to the “side-polar” aggregates formed by other nonmuscle myosins and by smooth muscle myosin (Craig R, Megerman J: J Cell Biol 75:990, 1977; Hinssen H, D'Haese J, Small JV, Sobieszek A: J Ultrastruct Res 64:282, 1978). Slow precipitation of myosin with copurified RNA generates linear filaments with repeat intervals of 290 and 650 nm.Other polyanions were tested for their effects on myosin aggregation. Total RNA and ribosomal RNA from Dictyostelium, when added to RNA-free myosin, also induced the extensive linear aggregation seen with the copurified RNA/myosin complex, although higher concentrations of RNA were required to obtain quantitatively the same effect. DNA and heparin were also effective inducers of linear aggregation, whereas homopolymers of nucleotides and of acidic or basic amino acids were poorly effective.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 57
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 293-298 
    ISSN: 0091-7419
    Schlagwort(e): SEM ; chemical carcinogenesis in vitro ; epithelial liver cell cultures ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: A scanning electron microscopy study was carried out on differentiated liver cells transformed in vitro by three chemical carcinogens into cells that give rise to carcinomas. The results indicate that the transformed cells grow as a rule in tightly adherent monolayers but differ in topography. There is a tendency toward heterogeneity in cell shape compared to the normal and on the whole toward a larger number of surface microvilli in the malignant cell population. However, both in sparse and confluent cultures the topographic differences are often not striking enough to unequivocally distinguish single neoplastic cells from the normal.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 58
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 321-334 
    ISSN: 0091-7419
    Schlagwort(e): denervated sarcolemma ; nonsynaptic acetylcholine receptors ; 125I-α-bungarotoxin ; ferritin-α-bungarotoxin ; electron microscopy ; freeze-fracture ; freeze-etching ; autoradiography ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: The nonsynaptic sarcolemma of denervated skeletal muscle of rat shows an abundance of ∼15 nm intramembranous particles on the P face. These particles are either singly distributed or are in clusters, and they are essentially lacking from the comparable freeze-fractures of the innervated sarcolemma. Autoradiographic studies using 125I-α-bungarotoxin (BGT) on 1 μ-thick sections, and freeze-etch studies using ferritin-α-BGT conjugates on membrane fractions, show that the distribution of the label corresponds to the distribution of the 15-nm particles in the nonsynaptic sarcolemma. On the basis of these results and existing physiologic and biochemical data, it is suggested that the 15-nm intramembranous particles are components of the α-BGT binding sites, ie, acetylcholine (Ach) receptors, in the nonsynaptic sarcolemma of denervated muscle and that the two types of distributions represent two spatial manifestations of Ach receptor molecules. The significance of these findings in relation to synapse formation in denervated muscle is discussed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 59
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979) 
    ISSN: 0091-7419
    Schlagwort(e): Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 60
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 425-433 
    ISSN: 0091-7419
    Schlagwort(e): rat liver ribosomal proteins ; amino-terminus ; yeast ribosomes ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: The sequence of the amino-terminal region of eleven rat liver ribosomal proteins-S4, S6, S8, L7a, L18, L27, L30, L37a, and L39 - was determined. The analysis confirmed the homogeneity of the proteins and suggests that they are unique, since no extensive common sequences were found. The N-terminal regions of the rat liver proteins were compared with amino acid sequences in Saccharomyces cerevisiae and in Escherichia coli ribosomal proteins. It seems likely that the proteins L37 from rat liver and Y55 from yeast ribosomes are homologous. It is possible that rat liver L7a or L37a or both are related to S cerevisiae Y44, although the similar sequences are at the amino-terminus of the rat liver proteins and in an internal region of Y44. A number of similarities in the sequences of rat liver and E coli ribosomal proteins have been found; however, it is not yet possible to say whether they connote a common ancestry.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 61
    ISSN: 0091-7419
    Schlagwort(e): nuclear matrix ; estrogen ; RNA ; uridine ; Xenopus laevis ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: At various times following estorgen administration, the nuclear matrix was isolated from the liver of male Xenopus laevis by sucrose gradient centrifugation of nuclei treated with a high-salt buffer and DNase I in the presence of a proteolytic inhibitor (PMSC - phenylmethyl sulfonyl chloride). Electron micrographs of the nuclear matrix demonstrate a sponge-like network attached to a well-defined inner envelope with a ribosome-free outer envelope. Chemical analyses show that the HSB-DNase-treated nuclei consist of 16% DNA, 2% RNA, and 82% protein, a composition that is consistent with that of nuclear matrices isolated from other species. The specific activity of the matrix-associated RNA following estrogen treatment appears to be maximally enhanced after 5 h and decreases until approximately 12 h, when the activity begins to increase again.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 62
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979) 
    ISSN: 0091-7419
    Schlagwort(e): Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 63
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 79-120 
    ISSN: 0091-7419
    Schlagwort(e): Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 64
    ISSN: 0091-7419
    Schlagwort(e): vertebrate photoreceptor ; cyclic GMP ; cyclic nucleotide regulation ; phosphodiesterase ; light activated GTPase ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: We report experiments which involve a light sensitive GTPase in the light dependent activation of retinal rod 3′5′-cyclic guanosine monophosphate (cGMP) phosphodiesterase (PDE). The data suggest that the light activated GTPase is intermediate between rhodopsin and PDE in the light-dependent activation sequence. We list the many striking similarities between hormone sensitive adenylate cyclase and light activated PDE in order to emphasize that the findings presented herein may have predictive value for ongoing studies of the hormone sensitive adenylate cyclase specifically regarding the role of the hormone activated GTPase in the activation sequence.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 65
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 359-364 
    ISSN: 0091-7419
    Schlagwort(e): ribosomes ; crystallization ; hypothermia ; chick embryos ; degeneration ; cell suffering ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: The relationship between ribosome crystallization and cell degeneration has been studied in chick embryos at various temperatures, and new methods of inducing ribosome microcrystals are described. A model is discussed that reinterprets the role of low temperatures in these phenomena and provides a unitary explanation of the various cases in which the occurrence of ribosome crystallization in chick embryos has been reported.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 397-404 
    ISSN: 0091-7419
    Schlagwort(e): electron microscopy ; hybrid ribosome ; ribosome structure ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Small 40S Artemia salina and large 50S Escherichia coli ribosomal subunits can be assembled into 73S hybrid monosomes active in model assays for protein synthesis. The reciprocal combination-small 30S E coli and large 60S A salina-fails to form hybrids. The 73S hybrid particles strongly resemble homologous 70S E coli and 80S A salina monosomes. The morphologic differences between the corresponding eukaryotic and prokaryotic ribosomal particles, established by electron microscopy, do not significantly affect the assembly and mutual orientation of 40S A salina and 50S E coli subunits in the heterologous monosome. The fact that the structure of the interface, the supposed site of protein synthesis, is preserved in the active hybrid implies that retention or loss of biologic activity of hybrid ribosomes is determined by the extent of conformational changes in the interface.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 67
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 433-441 
    ISSN: 0091-7419
    Schlagwort(e): macrophage (alveolar) ; plasma membrane ; Ca2+-ATPase reaction ; membrane phosphorylation ; Ca2+ buffering ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: ATPase activity and phosphorylation by [γ-32P] ATP of isolated plasma membrane of alveolar macorphages are stimulated in a parallel fashion by physiologic concentrations of Ca2+, with half-maximal activating effect of this ion at (3-7) × 10-7 M. For various membrane preparations, a direct proportionality exists between Ca2+-dependent ATPase activity and amount of 32P incorporated. Labeling of membrane attains the steady-state level by 10 sec at 0°C, and is rapidly reversed by adenosine diphosphate (ADP). K+ decreases the amount of membrane-bound 32P, mainly by enhancing the rate of dephosphorylation of the 32P-intermediate. Hydroxylamine causes a release of about 90% of 32P bound to the membrane, thus indicating that the 32P-intermediate contains an acyl-phosphate bond. When the labeled plasma membrane is solubilized and electrophoresed on acrylamide gels in the presence of sodium dodecyl sulphate, the radioactivity appears to be largely associated with a single protein fraction of 132,500 ± 2,000 apparent molecular weight. These features of the macrophage Ca2+-ATPase suggest that the enzyme activity might be part of a surface-localized Ca2+-extrusion system, participating in the regulation of Ca2+-dependent activities of the macrophage.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 68
    ISSN: 0091-7419
    Schlagwort(e): cell adhesion ; adhesion proteins ; fibronectin ; chondronectin ; collagen substrates ; gangliosides ; cell surface ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Fibronectin mediates the adhesion of fibroblasts to collagen substrates, binding first to the collagen and then to the cells. We report here that the interaction of the cells with the fibronectin-collagen complex is blocked by specific gangliosides, GD1 a and GT1, and that the sugar moieties of these gangliosides contain the inhibitory activity. The gangliosides act by binding to fibronectin, suggesting that they may be the cell surface receptor for fibronectin. Evidence is presented that other adhesion proteins or mechanisms of attachment exist for chondrocytes, epidermal cells, and transformed tumorigenic cells, since adhesion of these cells is not stimulated by fibronectin. Chondrocytes adhere via a serum factor that is more temperature-sensitive and less basic than fibronectin. Unlike that of fibroblasts chondrocyte adhesion is stimulated by low levels of gangliosides. Epidermal cells adhere preferentially to type IV (basement membrane) collagen but at a much slower rate than fibroblasts or chondrocytes. This suggests that these epidermal cells synthesize their own specific adhesion factor. Metastatic cells cultured from the T241 fibrosarcoma adhere rapidly to type IV collagen in the absence of fibronectin and do not synthesize significant amounts of collagen or fibronectin. Their growth, in contrast to that of normal fibroblasts, is unaffected by a specific inhibitor of collagen synthesis. These data indicate the importance of specific collagens and adhesion proteins in the adhesion of certain cells and suggest that a reduction in the synthesis of collagen and of fibronectin is related to some of the abnormalities observed in transformed cells.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 69
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 117-122 
    ISSN: 0091-7419
    Schlagwort(e): dynein ATPase ; latency ; high-affinity binding site ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: The enhancing effect of low concentrations (eg, 8 μM) of bis(4-fluoro-3-nitrophenyl)sulfone (FNS) on 30S dynein ATPase activity is increased when 1 mM dithiothreitol (DTT) is present. The effect of FNS + DTT is optimal at pH 7.5. Activation of the latent ATPase activity of 30S dynein by FNS + DTT is partially prevented by 1-3 μM ATP. Adenylylimidodiphosphate (AMP-PNP) is less effective than ATP, while β,γ-methylene-adenosine triphosphate (AMP-PCP), though a much stronger inhibitor of ATPase activity than AMP-PNP, does not protect against enhancement. These results demonstrate the presence of a high-affinity ATP-binding site on 30S dynein.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 70
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979) 
    ISSN: 0091-7419
    Schlagwort(e): Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 71
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 467-476 
    ISSN: 0091-7419
    Schlagwort(e): metastatic potential ; growth rates ; chromosome number and range ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: We investigated whether the metastatic potential of various tumor cell lines was related to chromosome counts or to rate of growth in vitro or in vivo. Clones of known metastatic potential derived from a C3H- fibrosarcoma induced by UV radiation (UV-2237) and from C57BL/6 B16 melanoma were tested for these characteristics. No correlation was found between the growth rate of these clones in monolayer culture or at a subcutaneous site and their ability to produce metastases. The cells from clones of UV-2237 were mainly in the diploid range with only one exception, and the B16 clones were all hyperploid. Thus, there was also no correlation between malignant behavior of the clones and gross changes in chromosome number.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 72
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 493-502 
    ISSN: 0091-7419
    Schlagwort(e): cell surface ; plasma membrane ; glycoproteins ; affinity chromatography ; lectins ; Novikoff hepatocellular carcinoma ; neuraminidase ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Novikoff hepatocellular carcinoma cells were radioiodinated by a cell surface-specific method using lactoperoxid ase/125I. The iodinated proteins were solubilized in 0.5% Nonidet P-40 and subjected to affinity chromatography on Sepharose-conjugated lectins (Ricinus communis agglutinins I or II, soybean agglutinin, concanavalin A, or wheat germ agglutinin) and analyzed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Almost all the iodinated proteins bound to one or more of the Sepharose-conjugated lectins, presumptive evidence that these peptides are glycosylated. Lectin affinity chromatography resolved defined subsets of iodinated glycoproteins and suggested that certain glycoproteins could be fractionated on the basis of heterogeneity of their heterosaccharide moieties. Incubation of the iodinated cells with neuraminidase resulted in increased binding of iodinated proteins to Sepharose-conjugated Ricinus communis agglutinins I and II and soybean agglutinin and decreased binding to Sepharose-conjugated wheat germ agglutinin. Binding of iodinated proteins to concanavalin A was unaffected by neuraminidase treatment of the cells. These studies demonstrate the utility of lectins for the multicomponent analysis of plasma membrane proteins.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 73
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 539-546 
    ISSN: 0091-7419
    Schlagwort(e): SV40 transformation ; tumorigenicity ; anchorage independence ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: A syndrome of in vitro properties correlates with the tumorigenicity of SV40-transformed rodent cells. These properties are plasminogen activator production, loss of large actin cables, and anchorage-independent growth. An established rat fibroblast line, its SV40 transformant, several T-antigen negative revertants, and a spontaneous retransformant isolated form one of the revertants were analyzed in vivo for their tumorigenicity and in vitro for the syndrome. The two transformed lines were highly tumorigenic, and had clearly abnormal in vitro properties. The parental rat line was weakly tumorigenic in nude mice and demonstrated a slightly transformed response in the in vitro assays. The revertants were completely nontumorigenic. Expression of the in vitro syndrome was not uniform for all revertants; however, most cell lines maintained the correlation of the syndrome and tumorigenicity.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 74
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 563-577 
    ISSN: 0091-7419
    Schlagwort(e): plasma membrane ; lectin receptors ; affinity chromatography ; membrane proteins ; hybridoma ; monoclonal antibody ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Concanavalin A-binding (Con A)-binding cell surface glycoproteins were isolated, via Con A-affinity chromatography, from Triton X-100-solubilized Chinese hamster ovary (CHO) cell plasma membranes. The Con A binding glycoproteins isolated in this manner displayed a significantly different profile on sodium dodecyl sulfate-polyacrylamide gels than did the Tritonsoluble surface components, which were not retarded by the Con A-Sepharose column. [125I]-Con A overlays of the pooled column fractions displayed on sodium dodecyl sulfate-polyacrylamide gel electro-phoresis (SDS-PAGE) demonstrated that there were virtually no Con A receptors associated with the unretarded peak released by the Con A-Sepharose column, whereas the material which was bound and specifically eluted from the Con A-Sepharose column with the sugar hapten α-methyl-D-mannopyranoside contained at least 15 prominent bands which bound [125I]-Con A.In order to produce monoclonal antibodies against various cell surface Con A receptors, Balb/c mice were immunized with the pooled Con A receptor fraction. Following immunization spleens were excised from the animals and single spleen cell suspensions were fused with mouse myeloma P3/X63-Ag8 cells. Numerous hybridoma clones were subsequently picked on the basis of their ability to secrete antibody which could bind to both live and glutaraldehyde-fixed CHO cells as well as to the Triton-soluble fraction isolated from the CHO plasma membrane fraction. Antibody from two of these clones was able to precipitate a single [125I]-labeled CHO surface component of ∼265,000 daltons.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 75
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 9-24 
    ISSN: 0091-7419
    Schlagwort(e): nascent chains ; co-translational modification ; glycosylation ; polypeptide folding ; covalent assembly ; heavy and light chains ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: We have investigated the in vivo co-translational covalent modification of nascent immunoglobulin heavy and light chains. Nascent polypeptides were separated from completed polypeptides by ion-exchange chromatography of solubilized ribosomes on QAE-Sephadex. First, we have demonstrated that MPC 11 nascent heavy chains are quantitatively glycosylated very soon after the asparaginyl acceptor site passes through the membrane into the cisterna of the rough endoplasmic reticulum. Nonglycosylated completed heavy chains of various classes cannot be glycosylated after release from the ribosome, due either to rapid intramolecular folding and/or intermolecular assembly, which cause the acceptor site to become unavailable for the glycosylation enzyme. Second, we have shown that the formation of the correct intrachain disulfide loop within the first light chain domain occurs rapidly and quantitatively as soon as the appropriate cysteine residues of the nascent light chain pass through the membrane into the cisterna of the endoplasmic reticulum. The intrachain disulfide loop in the second or constant region domain of the light chain is not formed on nascent chains, because one of the cysteine residues involved in this disulfide bond does not pass through the endoplasmic reticulum membrane prior to chain completion and release from the ribosome. Third, we have demonstrated that some of the initial covalent assembly (formation of interchain disulfide bonds) occurs on nascent heavy chains prior to their release from the ribosome. The results are consistent with the pathway of covalent assembly of the cell line, in that completed light chains are assembled onto nascent heavy chains in MPC 11 cells (IgG2b), where a heavy-light half molecule is the major initial covalent intermediate; and completed heavy chains are assembled onto nascent heavy chains in MOPC 21 cells (IgG1), where a heavy chain dimer is the major initial disulfide linked intermediate.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 76
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 33-49 
    ISSN: 0091-7419
    Schlagwort(e): cell enucleation ; cell reconstruction ; nuclear control of tumorigenicity ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: The techniques of somatic cell hybridization have provided a valuable means of studying mechanisms of regulation of mammalian cell differentiation and transformation. Most previous studies have indicated that fusions between tumorigenic and nontumorigenic cells result in hybrid cells that are usually tumorigenic. In recent years it has been demonstrated that the phenotypic expression of tumorigenicity is at least partially due to the extensive chromosome loss that occurs in most interspecific and some intraspecific hybrid cells. In the present study we have utilized enucleation techniques that permit cells to be divided into nuclear (karyoplast) and cytoplasmic (cytoplast) cell fragments. Even though these nuclear and cytoplasmic fragments are metabolically stable for short periods of time, in our hands they ultimately degenerate. Viable cells can be reconstructed by PEG-induced fusion of karyoplasts to cytoplasts. Since reconstructed cells apparently do not segregate chromosomes, they may provide a clearer understanding of the interactions between the nucleus and the cytoplasm in the control of the expression of tumorigenicity. We have reconstructed cells using karyoplasts from the tumorigenic Y-1 cell line and cytoplasts from a nontumorigenic cell line, A-MT-BU-A1. In addition we have reconstructed cells containing Y-1 cytoplasts and A-MT-BU-A1 karyoplasts. The reconstructed cells porduced were assayed for tumorigenicity by their ability to grow in soft agar and in nude mice. The results of these experiments indicate that the reconstructed cells containing a tumorigenic nucleus and a nontumorigenic cytoplasm ultimately are tumorigenic and conversely the reconstructed cells containing a nontumorigenic nucleus and a tumorigenic cytoplasm are nontumorigenic. These experiments support the concept that with these cell lines the nucleus (karyoplast) is sufficient to control the phenotypic expression of tumorigenicity.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
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  • 77
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979) 
    ISSN: 0091-7419
    Schlagwort(e): Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 78
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 123-138 
    ISSN: 0091-7419
    Schlagwort(e): pea stem membranes ; L-cell membranes ; polyisoprenyl oligosaccharides ; glycoprotein synthesis ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Membrane preparations from growing regions of pea stems and activelydividing mouse L-cells form lipid-linked saccharides from GDP-mannose and UDP-N-acetylglucosamine. These lipids have properties which are consistent with those of mono-and di-phosphoryl polyisoprenyl derivatives.In experiments using plant membranes, the monophosphoryl derivative labeled with GDP-(14C) mannose contains mannose only, while the diphosphoryl derivative labeled with the same nucleotide sugar is heterogeneous, containing oligosaccharides corresponding to mannosaccharides of 5, 7, and 9-12 residues. Only the diphosphoryl polyisoprenyl derivatives are labeled with UDP-(14C)glucosamine and these contain predominantly chitobiose and N-acetylglucosamine itself. Unlabeled GDP-mannose added after UDP-N-acetyl (14C)glucosamine results in the formation of higher lipid-linked oligosaccharides which are apparently the same as those which are labeled with GDP-(14C)mannose alone. Incubation of the membranes with GDP-(14C)mannose in the presence of Mn2+, unlabeled UDP-glucose or unlabeled UDP-N-acetylglucosamine results in marked changes in the accumulation of both the polyisoprenyl monophosphoryl mannose and polyisoprenyl diphosphoryl oligosaccharides.Animal cell membranes synthesise lipid-linked oligosaccharides when incubated with UDP-N-acetylglucosamine and GDP-mannose. These oligosaccharides are similar in size to those synthesised by the plant membranes but their formation is more efficient. The potential roles of these compounds in glycoprotein biosynthesis in both plant and animal tissues is discussed.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 79
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 167-174 
    ISSN: 0091-7419
    Schlagwort(e): cellular adhesion ; platelets ; fibronectin ; hemostasis ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Platelets are cells which develop adhesive properties following stimulation. Since fibronectin (fn) mediates adhesive properties of several cells, we sought evidence for platelet associated fn. Lysates of suspensions of washed human platelets containing ≤50 ng soluble fn/109 cells contained 2.85 μg fn antigen per 109 cells. The platelet fn antigen competition curve showed a similar slope to the curve for purified plasma fn suggesting antigenic identity. Immunofluorescent staining for fn was minimal in intact cells suggesting that the majority of fn antigen is intracellular. In permeable platelets, fluorescent staining for fn was seen in a punctate distribution suggesting a granule localization. Stimulation of platelet secretion by thrombin released platelet fn antigen. Suramin, a drug which inhibits platelet secretion, inhibited fn release. The apparent secretion of platelet fn, taken with the immunofluorescent data, support the localization of a portion of platelet fn antigen in a storage granule.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 80
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 175-187 
    ISSN: 0091-7419
    Schlagwort(e): growth control ; 3T3 cells ; Schwann cells ; neurites ; plasma membranes ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Control of cell growth by cell to cell contact is reviewed with particular emphasis on two systems - contact inhibition of growth observed with Swiss 3T3 cells and the mitogenic stimulation of Schwann cells by dorsal root ganglia neurites. In both cases the biological effect can be reproduced by the addition of surface membranes to the corresponding cells. In the case of contact inhibition of 3T3 cells, biological activity appears to correlate with membrane binding to the cells. An octylglucoside extract of 3T3 plasma membranes retains the biological activity (growth inhibition) of the original membranes.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 81
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 207-216 
    ISSN: 0091-7419
    Schlagwort(e): renal epithelium ; primary cultures ; prostaglandins ; mammalian cell growth ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Madin Darby canine kidney cells can grow in synthetic medium supplemented with 5 factors - insulin, transferrin, prostaglandin E1, hydrocortisone and triiodothyronine - as a serum substitute. These 5 factors permit growth for one month in the absence of serum, and a growth rate equivalent to that observed in serum-supplemented medium. Dibutyryl cAMP substitutes for prostaglandin E1 in the medium, suggesting that increased growth of Maden Darby canine kidney cells results from increased intracellular cAMP. Potential applications of the serum-free medium are discussed. The medium permits the selective growth of primary epithelial cell cultures in the absence of fibroblast over-growth, and a defined analysis of the mechanisms by which hormones regulate hemicyst formation.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 82
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 217-225 
    ISSN: 0091-7419
    Schlagwort(e): fibrosarcoma culture media ; gel permeation chromatography ; fibronectin-radioimmunoassay ; fibronectin-releasing peptides ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: A sensitive radioimmunoassay, specific for human fibronectin, was used to measure the ability of certain biologically active polypeptides to release fibronectin from cultured human lung fibroblasts into their culture media. Concentrated, serum-free culture supernatant from a human fibrosarcoma cell line was fractionated by gel filtration chromatography in the presence of acetic acid. Various polypeptides with molecular weights between 46,000 and 6,000 were tested for their ability to release fibronectin from cells. The column fraction, containing polypeptides with an apparent molecular weight of 10,000, exhibited the ability to rapidly release fibronectin from target cells. The activity could be inhibited by phenylmethyl sulphonylfluoride. Several other hormonal factors, tested in parallel with the column fractions, failed to show this effect. The 10,000 dalton molecular weight polypeptides may represent a family of cellular gene products responsible for maintenance of low levels of surface associated fibronectin in fibrosarcoma cells and thus be related to their infiltrating properties by preventing the formation of the extracellular matrix.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 83
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 227-235 
    ISSN: 0091-7419
    Schlagwort(e): fibronectin ; factor XIII ; transglutaminase ; collagen ; polyamine ; ∊(γ-glutamyl)-lysin ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Soluble fibronectin is found in body fluids and media of cultured adherent cells. Insoluble fibronectin is found in tissue stroma and in extracellular matrices of cultured cells. Fibronectin is a substrate for factor XIIIa (plasma transglutaminase) and can be cross-linked to collagen and to the α chain of fibrin. We have used sodium dodecyl sulfate-polyacrylamide gel electrophoresis to investigate the possibility that factor XIIIa -mediated cross-linking is influenced by polyamines. Spermidine inhibited cross-linking between fibronectin and type I collagen, isolated α1 (I) collagen chains, or iodinated cyanogen bromide fragment 7 of α1 (I) chains (125I-α1 (I)-CB7). Half-maximal inhibition of crosslinking between 125I-α1 (I)-CB7 and fibronectin was observed when 0.1 mM spermine or spermidine was present. Spermidine, 0.7 mM, partially inhibited cross-linking between fibronectin and the α chain of fibrin but failed to inhibit cross-linking between the fibrin monomers of a fibrin clot. Spermidine also failed to inhibit cross-linking between fibronectin molecules when aggregation of fibronectin was induced with dithiothreitol. In contrast, 0.7 mM monodansylcadaverine inhibited fibronectin-collagen, fibronectin-fibrin, fibronectin-fibronectin, and fibrin-fibrin cross-linking. Spermidine or spermine, 0.7 mM, enhanced the cross-linking between molecules of partially amidinated fibronectin, suggesting that N1,8-(di-γ-glutamyl)-polyamine cross-linkages were formed. Spermidine and spermine failed to enhance cross-linking between monomers of amidinated fibrin. These results indicate that physiologic concentrations of polyamines specifically disturb transglutaminase-catalyzed cross-linking between fibronectin and collagen.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 84
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 237-250 
    ISSN: 0091-7419
    Schlagwort(e): coated vesicles ; coat dissembly ; coat reassembly ; coat dissociation ; clathrin ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Disruption of the coat of coated vesicles is accompanied by the release of clathrin and other proteins in soluble form. The ability of solubilized coated vesicle proteins to reassemble into empty coats is influenced by Mg2+, Tris ion concentration, pH, and ionic strength. The proteins solubilized by 2 M urea spontaneously reassemble into empty coats following dialysis into isolation buffer (0.1 M MES-1 mM EGTA-1 mM MgCl2-0.02% NaN3, pH 6.8). Such reassembled coats have sedimentation properties similar to untreated coated vesicles. Clathrin is the predominant protein of reassembled coats; most of the other proteins present in native coated vesicles are absent. We have found that Mg2+ is important in the coat assembly reaction. At pH 8 in 0.01 M or 0.1 M Tris, coats dissociate; however, 10 mM MgCl2 prevents dissociation. If the coats are first dissociated at pH 8 and then the MgCl2 raised to 10 mM, reassembly occurs. These results suggest that Mg2+ stabilizes the coat lattice and promotes reassembly. This hypothesis is supported by our observations that increasing Mg2+ (10 μM-10 mM) increases reassembly whereas chelation of Mg2+ by (EGTA) inhibits reassembly. Coats reassembled in low-Tris (0.01 M, pH 8) supernatants containing 10 mM MgCl2 do not sediment, but upon dialysis into isolation buffer (pH 6.8), these coats become sedimentable. Nonsedimentable coats are noted also either when partially purified clathrin (peak I from Sepharose CL4B columns) is dialyzed into low-ionic-strength buffer or when peaks I and II are dialyzed into isolation buffer. Such nonsedimentable coats may represent intermediates in the assembly reaction which have normal morphology but lack some of the physical properties of native coats. We present a model suggesting that tightly intertwined antiparallel clathrin dimers form the edges of the coat lattice.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 85
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 259-267 
    ISSN: 0091-7419
    Schlagwort(e): cell surface receptors ; proteolysis of receptors ; positive or negative regulation ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Addition of highly purified thrombin t o cultures of several kinds of nondividing fibroblasts brings about cell division. This stimulation occurs in serum-free medium, permitting studies on its mechanism under chemically defined conditions. Previous studies have shown that action of thrombin a t the cell surface is sufficient to cause cell division and that the proteolytic activity of thrombin is required for its mitogenic effect. These results prompted experiments which showed that there is a cell surface receptor for thrombin and that thrombin must hind to its receptor and cleave it to stimulate cell division. Some of the thrombin that hinds to its receptors becomes attached to them by a linkage that appears to be covalent. However, it is presently unknown whether this direct thrombin receptor complex plays a role in the stimulation.These results raise a number of question that should be explored in future studies. They also provide a foundation on which to build hypotheses about tentative molecular mechanisms that might be involved in the stimulation. Knowledge that thrombin must cleave its receptor to bring about cell division suggests two alternative mechanisms for stimulation by proteolysis. In one the receptor is a negative effector which prevents cell division when it is intact, but not after it has been cleaved. Alternatively, a fragment of the receptor could be a positive effector. In this mechanism, proteolysis by thrombin would produce a specific receptor fragment which brings about cell proliferation. If every protease which cleaves the receptor also stimulates cell division, the receptor is probably a negative effector. In contrast, if certain proteases cleave the receptor but do not stimulate the cells, a fragment of the receptor is likely a positive effector. With negative regulation by the receptor, the controlling events would occur before proteolysis of it, and it might be possible to find putative regulatory molecules by identification of nearest neighbors of the receptor. This should be possible by using bifunctional crosslinking reagents. If a fragment of the thrombin receptor turns out to be a positive effector, it should be possible to identify and study fragments by analyzing the metabolic fate of the receptor. Techniques are now available for this kind of analysis and it should also be possible to determine whether receptor fragments remain in the membrane or whether they are translocated to specific sites within the cell. A critical question to be asked is which of these events and interactions involving the thrombin receptor are necessary for stimulation of cell division. It now appears that the best way to answer this question is to examine these events in a large number of cloned cell populations that are responsive or unresponsive to the mitogenic action of thrombin. If a thrombin-mediated event occurs in all responsive clones but is altered or absent in sonie unresponsive clones, it is probably necessary for stimulation of cell division.
    Materialart: Digitale Medien
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  • 86
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 295-309 
    ISSN: 0091-7419
    Schlagwort(e): threshold effects ; liposomes ; aggregation ; ricin ; concanavalin A ; synthetic glycolipids ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Cholesterol analogs containing sugar residues linked by spacer groups to the cholesterol O can be incorporated into egg yolk lecithin small unilamellar liposomes. The synthetic glycolipid analogs distribute evenly on both sides of the bilayer. These liposomes are aggregated by the appropriate lectin. For example, when the sugar residue is a β-galactoside the liposomes are aggregated by ricin and when it is an α-mannoside they are aggregated by Con A. The lectin-mediated aggregation of these liposomes is reversed by the addition of the appropriate sugar. The rates but not the extents of aggregation of these liposomes are highly sensitive to the amount of glycolipid incorporated. Below approximately 5% glycolipid incorporation the rate of the lectin-mediated aggregation of these liposomes is exceedingly slow, whereas above this level rapid aggregation proceeds. At all concentrations studied the synthetic glycolipids are incorporated in a unimodal fashion so that the observed threshold effects cannot be based on possible differences in the manner in which the glycolipids are incorporated at different concentrations. This conclusion is based on (1) studies with galactose oxidase that show that the percentage of galactose oxidation in a liposome prepared from a galactosyl-containing glycolipid is independent of glycolipid concentration, and (2) studies on the aggregation of liposomes containing mixed glycolipids in which the glycolipids are shown to behave independently. The importance of a critical density of membrane-bound receptors in order for aggregation to occur is discussed.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 87
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 311-317 
    ISSN: 0091-7419
    Schlagwort(e): dynein ; flagella ; ATPase ; sperm motility ; sea urchin ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: A high-resolution sodium dodecyl sulfate polyacrylamide gel electrophoresis system has been used to show the presence, in both whole sperm and isolated flagellar axonemes, of eight polypeptides migrating in the 300,000-350,000 molecular weight range characteristic of the heavy chains of dynein ATPase. Previously, only five such chains have been discernible. Extraction of isolated axonemes for 10 min at 4°C with a solution containing 0.6 M NaCl, pH 7, releases a mixture of particles that separate, in sucrose density gradient centrifugation, into a major peak, dynein 1 ATPase, sedimenting at 21 S and a minor peak at 12-14S. The polypeptide compositions of these two peaks are different. The dynein 1 peak, which contains most of the protein on the gradient, contains approximately equal quantities of two closely migrating heavy chains, with a small amount of a third, more slowly migrating chain; no other heavy chains appear in this peak. Two groups of smaller polypeptides (three intermediate chains, within the apparent molecular weight range 76,000-122,000 and four newly discovered light chains, within the apparent molecular weight range 14,000-24,000) cosediment with the 21 S peak. The heavy chain composition of the 12-14S peak is more complex, all eight heavy chains occurring in approximately the same ratios as occur in intact axonemes.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 88
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 339-347 
    ISSN: 0091-7419
    Schlagwort(e): switch hypothesis ; cilia ; motility ; vanadate ; calcium ; dynein ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Lateral (L) cilia of freshwater mussel (Margaritana margaritifera and Elliptio complanatus) gills can be arrested in one of two unique positions. When treated with 12.5 mM CaCl2 and 10-5 M A23187 they arrest in a “hands up” position, ie, pointing frontally. When treated with approximately 10 mM vanadate (V) they arrest in a “hands down” position, ie, pointing abfrontally. L-cilia treated with 12.5 mM CaCl2 and 1 mM NaN3 also arrest in a “hands down” position; substitution of 20 mM KC1 and 1 mM NaN3 causes cilia to move rapidly and simultaneously to a “hands up” position.The observations suggest that there are two switching mechanisms for activation of active sliding in ciliary beat one at the end of the recovery stroke and the other at the end of the effective stroke; the first is inhibited by calcium and the second by vanadate or azide. This is consistent with a model of ciliary beating where microtubule doublet numbers 1, 2, 3, and 4 are active during the effective stroke while microtubule doublets numbers 6, 7, 8, and 9 are passive, and the converse occurs during the recovery stroke.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 89
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 429-444 
    ISSN: 0091-7419
    Schlagwort(e): (H++K+)-ATPase ; transport ATPase ; proton transport ; phospholipids ; phospholipase A2 ; CD spectrum ; gastric ATPase ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: The phospholipid and fatty acid composition and role of phospholipids in enzyme and transport function of gastric (H++K+)-ATPase vesicles was studied using phospholipase A2 (bee venom). The composition (%) was phosphatidylcholine (PC) 33%; sphingomyelin (sph) 25%; phosphatidylethanolamine (PE) 22%; phosphatidylserine (PS) 11%; and phosphatidylinositol (PI) 8%. The fatty acid composition showed a high degree of unsaturation. In both fresh and lyophilized preparations, even with prolonged incubation, only 50% of phospholipids were hydrolyzed, but the amount of PE and PS disappearing was increased following lyophilization. There was a marked decrease in K+-ATPase activity (75%) but essentially no loss of the associated K+ p-nitrophenyl phosphatase was found. ATPase activity could be largely restored by various phospholipids (PE 〉 PC 〉 PS). There was also an increase in Mg2+-ATPase activity, partially reversed in fresh preparations by the addition of phospholipids (PE 〉 PS 〉 PC). Proton transport activity of the preparation was rapidly inhibited, initially due to a large increase in the HC1 permeability of the preparation. Associated with these enzymatic and functional changes, the ATP-induced conformational changes, as indicated by circular dichroism spectra were inhibited.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 90
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 365-375 
    ISSN: 0091-7419
    Schlagwort(e): ribosomes ; crystallization ; hypothermia ; chick embryos ; degeneration ; nuclei ; nucleolar extrusions ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Ribosome crystallization within nuclei has been studied in chick embryos with procedures which increase its frequency by various orders of magnitude as compared to previous findings. The extrusion of ribosome microcrystals from nuclei is reported for the first time, and a model for the transfer of ribosomes from nucleus to cytoplasm is proposed.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 91
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 377-395 
    ISSN: 0091-7419
    Schlagwort(e): wet replicas ; microsurface spreading ; DNA ; subunits ; superbeads ; supercoils ; fibers ; chromosome bridges ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Superpacking of chromatin and the surface features of metaphase chromosomes have been studied by SiO replication of wet, unstained, and unfixed specimens in an exceedingly thin (≤ 1 nm) aqueous layer, keeping them wet. Hydrophilic Formvar substrates allow controlled thinning of the aqueous layer covering the wet specimens. Whole mounts of chromatin and chromosomes were prepared by applying a microsurface spreading method to swollen nuclei and mitotic cells at metaphase.The highest level of nucleosome folding of the inactive chromatin in chicken erythrocytes and rat liver nuclei is basically a second-order superhelical organization (width 150-200 nm, pitch distance 50-150 nm) of the elementary nucleosome filament. In unfavorable environments (as determined by ionic agents, fixative, and dehydrating agents) this superstructure collapses into chains of superbeads and beads. Formalin (10%) apparently attacks at discrete sites of chromatin, which are then separated into superbeads. The latter consist of 4-6 nucleosomes and seemingly correspond to successive turns of an original solenoidal coil (width 30-35 nm), which forms the superhelical organization. When this organization is unfolded, eg, in 1-2 mM EDTA, DNAse-sensitive filaments (diameter 1.7 nm) are seen to be wrapped around the nucleosomes.The wet chromosomes in each metaphase spread are held to each other by smooth microtubular fibers, 20-30 nm in diameter. Before they enter into a chromsome, these fibers branch into 9-13 protofilaments, each 5 nm wide. The chromosome surface contains a dense distribution of subunits about 10-25 nm in diameter. This size distribution corresponds to that of nucleosomes and their superbeads. Distinct from this beaded chromosome surface are several smooth, 23-30-nm-diameter fibers, which are longitudinal at the centromere and seem to continue into the chromatid structure. The surface replicas of dried chromosomes do not show these features, which are revealed only in wet chromosomes.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 92
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 10 (1979), S. 419-431 
    ISSN: 0091-7419
    Schlagwort(e): microtubules ; assembly ; protein-protein interactions ; electron microscopy ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Tubulin rings have been previously identified as composed of linear polymers of tubulin subunits, equivalent to a protofilament in the microtubule wall but in a curved rather than a straight conformation. We have examined and measured a number of different ring structures obtained under different conditions. The preferred curvature is indicated by a single ring of 380 Å outside diameter. Radially double rings consist of two coplanar rings of 460 Å and 350 Å outside diameter, held together by a pattern of eight identical contacts between the 40 Å subunits in the inner and outer rings. In some circumstances a larger ring, 570 Å diameter, can be added to the outside, or a smaller ring, 240 Å diameter, may be added to the inside of the radially double ring, in both cases repeating the pattern of eight radial contacts. The distortion of the filament from its relaxed 380 Å diameter curvature apparently can be made without disrupting the longitudinal bond between subunits in the filament, but must be stabilized by the energy of the radial contacts. All of these rings (single and radially double and triple) are observed to associate axially to form pairs or in some cases larger stacks. The radially double rings or an axially associated pair of these (quadruple ring) may also associate to form crystals. These are thin plates, up to 100 μm in extent and several μm thick which have been of limited use so far in diffraction studies because of irregularities in the packing of adjacent rings.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 93
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 95-104 
    ISSN: 0091-7419
    Schlagwort(e): fibronectin structure and properties ; cytoskeleton ; cell surface proteins ; fibronectin distribution ; fibronectin interactions ; transformation ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Fibronectin is a large glycoprotein at the cell surface of many different cell types; a related protein is present in plasma. Fibronectin is a dimer of 230,000-dalton subunits and also occurs in larger aggregates; it forms fibrillar networks at the cell surface, between cells and substrata and between adjacent cells, and it is not a typical membrane protein. Cell surface fibronectin is reduced in amount or absent on transformed cells and in many cases its loss correlates with acquisition of tumorigenicity and, in particular, metastatic ability. Exceptions to the correlations with transformation and tumorigenicity exist. Loss of fibronectin and the resulting reduced adhesion appear to be involved in pleiotrpoic alterations in cell behavior and may be responsible for several aspects of the transformed phenotype in vitro. Fibronectin interacts with other macromolecules (collagen/gelatin, fibrin/fibrinogen, proteoglycans) and is apparently connected to microfilaments inside the cell.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 94
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 349-359 
    ISSN: 0091-7419
    Schlagwort(e): colostrum ; milk ; serum ; growth factors ; mitogens ; DNA synthesis ; proliferation ; 3T3 cells ; serum-free growth ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Bovine milk contains growth promoting factors that stimulate DNA synthesis and cell division in confluent monolayers of quiescent Balb/c 3T3 cells. The growth factor activity was highest in colostrum obtained within 24 hours after birth of a calf. Samples of milk obtained 32 hours and 60 hours after birth were 20% and 1% as active respectively as was a sample obtained 8 hours after birth in stimulating DNA synthesis. No activity was detectable 3 days after birth or thereafter. A similar temporal dependence was found in sheep's milk. Bovine colostrum obtained on the day of a calf's birth can be substituted for serum and will support the growth of sparse Balb/c 3T3 cells to confluence. In Dulbecco's modified Eagle's medium (DMEM) supplemented with 2.5% (vol/vol) bovine colostrum, the number of Balb/c 3T3 cells in a dish increased 35-fold, from 2.0 × 104 cells to 7 × 105 cells. The generation time was approximately 38 hours. Proliferation of cells was characterized by formation of clusters of confluent Balb/c 3T3 cells which were smaller in size and more tightly packed than were Balb/c 3T3 cells grown to confluence in serum. No proliferation was detected in DMEM supplemented with milk obtained 10 days after birth of a calf or in DMEM supplemented with bovine serum albumen.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 95
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 321-326 
    ISSN: 0091-7419
    Schlagwort(e): bacteriophage T7 ; procapsid core ; electron microscopy ; mutant lysates ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: A cylindrical core previously demonstrated in a bacteriophage T7 procapsid (capsid I) has been further examined by electron microscopy. Fibrous extensions of the core have been observed; these fibers appear to connect the core to the capsid I envelope. After infection of a nonpermissive host with bacteriophage T7 amber mutant in any gene coding for a core protein, the resulting lysates contained more noncapsid assemblies of capsid envelope protien than did wild-type lysates; these assemblies had a mass two to at least 500 times greater than the mass of capsid I. This suggests that the internal core and fibers assist the assembly of subunits in the envelope of capsid I.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 503-515 
    ISSN: 0091-7419
    Schlagwort(e): glycoproteins ; two-dimensional electrophoresis ; differentiation ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: The present work examined the expression of cell surface glycoprotein antigens in cultured human cell lines. The set of glycoproteins studied was defined by their immunoreactivity with antiserum developed to Triton-solubilized extracts of placental brush border membranes. Studies were performed using cell lines of trophoblastic (BeWo, JEG-3) and nontrophoblastic (Chang liver cells) origin, as well as diploid fibroblast cell lines (WI-38, GM-38).Antiplacental brush border antiserum reacts with at least 19 distinct antigens present in placental membrane preparations, each of which can be resolved and identified in two-dimensional electrophoresis. The subunit molecular weight and isoelectric point for all components were defined by their positions in the two-dimensional matrix. Thirteen of these could be detected among the five cell lines examined by lactoperoxidase-catalyzed cell surface iodination. One of these 13 antigens has been identified as the placental isoenzyme of alkaline phosphatase (PAP). The expression of this component is limited to choriocarcinonia cells and Chang liver cells and it is not present in diploid fibroblasts. Under normal circumstances expression of PAP is unique to the differentiated placenta but has been frequently demonstrated in both trophoblastic and nontrophoblastic neoplasms.Two other antigens are variably expressed among the different cell types examined in the present study and their presence or absence was independent of the trophoblastic, epithelial nontrophoblastic, or fibroblastic origin of the cells.Ten surface antigens were expressed in all five cell lines. Six of these had previously been found common to membranes from three adult differentiated tissues, including liver and kidney, as well as placenta (Wada et al, J Supramol Struc 10(3):287-305, 1979). The presence of this set of antigens in cultured cells as well extends the possibility that these are ubiquitously expressed on human cell surfaces. Two other antigens observed in all cultured cells had been found in both placental and either kidney or liver membranes and may represent common functions shared by many tissues which are also necessary for growth in vitro. The two remaining placental antigens seen in all cultured cells have previously been shown to be absent in adult tissues. Their presence in cultured cells but not in the membranes of resting differentiated tissues may signify the expression of glycoproteins characteristic of trophoblasts in all cells adapted to growth in culture.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 11 (1979), S. 579-586 
    ISSN: 0091-7419
    Schlagwort(e): growth factors ; transferrin receptors ; mitogenesis ; mixed lymphocyte culture ; cell cycle ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: This report describes investigations of plasma membrane transferrin receptors on a variety of lymphoid cell lines and normal peripheral blood lymphocytes during activation and cell growth cycles. Transformed lymphoid cell lines have as many as 1,000 times the number of receptors found on normal resting lymphocytes. The number of iron transferrin receptors on continuous cell lines as well as normal human fibroblasts is down-regulated during the transition from log-phase growth to stationary plateau growth. When normal lymphocytes are transformed by mixed lymphocyte culture or mitogens, they rapidly express a 50-fold increase in the number of transferrin binding sites. This appearance of iron transferrin receptors anticipates nuclear changes during cell activation and subsequent mitosis of normal cells.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 139-150 
    ISSN: 0091-7419
    Schlagwort(e): fibronectin ; tumor ; malignancy ; cell shape ; hormone ; embryogenesis ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Frozen sections of tumors induced by injecting virally transformed cells into animals were stained for fibronectin by immunofluorescence. Many tumor cell lines do not express fibronectin in tumors in situ even though some of them express fibronection in culture. Cell shape and hormones appear to influence the expression of fibronectin in culture; however, it is nuclear how fibronection expression is regulated in vivo.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 165-175 
    ISSN: 0091-7419
    Schlagwort(e): microvilli ; Malpighian tubule ; cytoskeleton ; actin ; cell motility ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: The mitochondria in the lower Malpighian tubule of the insect Rhodnius prolixus can be stimulated by feeding in vivo and by 5-hydroxytryptamine in vitro, to move from a position below the cell cortex to one inside the apical microvilli. During and following their movement into the microvilli, the mitochondria are intimately associated with the microfilaments of the cell cortex and microvillar core bundle. Bridges approximately 14 nm in length and 4 nm in diameter are observed connecting the microvillar microfilaments to the outer mitochondrial membrane and microvillar plasma membrane. Depolymerization of all visible microtubules with colchicine does not inhibit 5-HT-stimulated mitochondrial movement. On the other hand, treatment with cytochalasin B does block mitochondrial movement, suggesting that microfilaments play a role in the mitochondrial motility. We have labeled the microvillar microfilaments, which are 6 nm in diameter, with heavy meromyosin, which supports the contention that they contain actin. A model of the mechanism of mitochondrial movement is presented in which mitochondria slide into position in the microvilli along actin-containing microfilaments in a manner analogous to the sliding actin-myosin model of skeletal muscle.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 12 (1979), S. 227-243 
    ISSN: 0091-7419
    Schlagwort(e): cloned hepatic cell line ; isolation of metastatic variants ; metastatic heterogeneity introduced by ascites passage ; metastatic homogeneity and stability ; quantitative lung colony assay ; scanning electron microscopy ; tumor cell arrest and survival ; Life Sciences ; Molecular Cell Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: An experimental system for the study of metastasis has been developed using an epithelioid cell line of hepatic origin which had previously been chemically transformed in vitro. These metastatic cells were studied in the syngeneic rat strain. The cloned parent cell line metastasizes only to the lungs following in travenous, subcutaneous, or intraperitoneal injection. The metastatic phenotype is stable during in vitro passage, and subclones from the parent clone have a metastatic capacity statistically similar to that of the parent clone. Following ascites passage of the parent cell line, the cell population obtained exhibits the same metastatic ability as the parent clone. However, subclones obtained from the ascites-passaged population exhibit metastatic heterogneity. This heterogeneity is introduced by the host passage and not by in vitro culture or subcloning. In the case of the two metastatic variants examined, the difference in the metastatic phenotype is found not to be due to differences in arrest or trapping of the cells but appears to be related to long-term survival and proliferation of the tumor cells following their arrest in the lungs. Morphologically the variants are very similar, and growth of the metastatic foci provokes a vigorous inflammatory response by the host.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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