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  • 1980-1984
  • 1975-1979  (280)
  • 1976  (280)
  • Biochemistry and Biotechnology  (174)
  • Ultrastructure  (106)
  • Nuclear reactions
Materialart
Erscheinungszeitraum
  • 1980-1984
  • 1975-1979  (280)
Jahr
  • 1
    ISSN: 1432-2307
    Schlagwort(e): Ultrastructure ; Thyroid ; Mucosal neuromas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Electron-microscopic and histochemical studies of thyroid tumor, tongue neuromas and eyelid neuromas from the lesions of a patient with medullary thyroid carcinoma were compared. In the thyroid tumor, a significant number of the C cells showed heterogeneity of granule types; no C cells, however, were identified in the tongue and eyelid neuromas. Amyloid was clearly shown by Congo red staining in the thyroid neoplasm and in the tongue neuromas. In all tissues, amyloid fibrils were found to be ultrastructurally closely associated with fibroblasts. These fingings suggest that the fibroblast rather than the C cell may have played the important role in the deposition of amyloid in this patient's thyroid carcinoma.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurology 213 (1976), S. 295-303 
    ISSN: 1432-1459
    Schlagwort(e): Neuronal ceroid lipofuscinosis ; Lipopigments ; Ultrastructure ; π-granules
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei einem Patienten mit spätinfantiler und 3 mit juveniler NCL wurden periphere Nerven verschiedener Herkunft (Armplexus, N. suralis und 2 Hirnnerven) elektronenmikroskopisch untersucht. Im Lichtmikroskop wurden keine signifikanten histologischen Veränderungen gefunden. Kurvilineäre und/oder Fingerabdruck-Einschlüsse konnten ultrastrukturell in jedem Fall festgestellt werden, und zwar hauptsächlich in Schwannschen Zellen. Außerdem fanden sich lamelläre π-granulaähnliche Cytosomen. Sie kamen in den juvenilen Fällen gewöhnlich gar nicht und in dem spätinfantilen Fall lediglich vereinzelt mit kurvilineären/Fingerabdruck-Profilen gemeinsam vor. Bei spärlichen Veränderungen an Axonen und Myelinscheiden könnten diese Cytosomen Zeichen einer chronischen Schädigung der Schwannschen zellen sein und die spezifische morphologische Ausprägung eines „cellulären Verschleißprozesses“ darstellen, wie er im Alter und bei der NCL diskutiert wird. Biopsien aus peripheren Nerven eignen sich aufgrund der zahlreichen π-Granula und ihrer Varianten weniger zur Diagnose der NCL als beispielsweise solche der Haut, der Skeletmuskulatur und des Rectums.
    Notizen: Summary Specimens of brachial plexus, sural nerve and two cranial nerves of one patient with the Jansky-Bielschowsky type and 3 patients with the Spielmeyer-Sjögren type of NCL were studied by electron microscopy. Significant light microscopic changes were absent in all specimens. Ultrastructurally, curvilinear and/or fingerprint inclusions were present in each case, located chiefly in Schwann cells. These diagnostic findings were, however, overshadowed by masses of lamellar π-granule-like cytosomes, usually not mixed with curvilinear or finger-print profiles in the juvenile cases and only rarely associated with curvilinear profiles in the late infantile case. Since secondary changes of axons and myelin sheaths were mild, these lamellar cytosomes might indicate chronic damage to Schwann cells, perhaps by “wear and tear” as seen in aging as well as NCL. On account of the abundance of π-granules in NCL, peripheral nerve biopsy appears less suitable for confirming this diagnosis than biopsy of skin, striated muscle and rectal tissue.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Planta 133 (1976), S. 15-19 
    ISSN: 1432-2048
    Schlagwort(e): Tropaeolum, Embryogenesis ; Differentiation ; Plastids ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Embryogeny in the nasturtium is characterized by the development of a large, tripartite suspensor and storing cotyledons. A light and electron microscopic study revealed an early diversification of the plastids in the various regions of the suspensor and the embryo proper. Amyloplasts are found in the developing cotyledons of the heart-like embryo, while chloroplasts occur within the meristematic part of the embryo and the adjacent portion of the suspensor. The cells between the meristem and the storing cotyledons display undifferentiated leukoplasts, whereas leukoplasts with an electron-dense matrix occur in the basal cell mass of the embryo-suspensor. Etioplasts develop in several cells of the placental haustorium of the suspensor. The carpel haustorium shows rather undifferentiated leukoplasts, which are transformed into electron-dense plastids during autolysis of the suspensor. This early plastidal differentiation in discussed with respect to its control and functional significance.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 371 (1976), S. 121-129 
    ISSN: 1432-2307
    Schlagwort(e): Compound cilia ; Axial filament complex ; Bronchitis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Atypical cilia in the bronchial mucosa of non-smoking women and in guinea-pig lungs were studied by the electron microscope. In human cases, numerous compound cilia were observed in the main bronchi. The largest one contained about 40 axial filament complexes in a ciliary shaft. Occasionally, atypical basal bodies were also seen. In the experimental model in guinea-pigs, 50% oxygen at one atmospheric pressure damaged the bronchial surface and resulted in degeneration and reduction of cilia and pellicular structures. The injury was not sufficiently severe to initiate adaptation and reparative mechanisms in the bronchial mucosa, and rapid renewal of the surface structures was found. The human cases were associated with bronchogenic carcinoma but the experimental model suggested that atypical cilia were not always related to pulmonary carcinogenesis.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 371 (1976), S. 161-170 
    ISSN: 1432-2307
    Schlagwort(e): Giant cell granuloma ; Histochemistry ; Ultrastructure ; Cell function ; Osteoclasts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die mehrkernigen Riesenzellen des zentralen Riesenzellgranuloms entstehen durch Zellfusion aus den Pericyten der Kapillaren. In der vorliegenden Studie werden die Funktionsmerkmale der Riesenzellen durch Kombination histologischer, histochemischer und elektronenmikroskopischer Methoden untersucht. In den mehrkernigen Riesenzellen ließen sich in Übereinstimmung mit älteren Untersuchungen die lysosomalen Enzyme saure Phosphatase und Aminopeptidase nachweisen. Das lysosomale System der Riesenzellen befähigt diese zur aktiven Phagocytoseleistung. Darüber hinaus können sich die Riesenzellen neugebildeten Geflechtknochenbälkchen anlagern und osteoclastäre Funktionen übernehmen. Die enzymhistochemische und funktioneile Ähnlichkeit mit den mehrkernigen Osteoclasten wirft die Frage nach einer vergleichbaren Cytogenese beider Zellformen auf.
    Notizen: Summary Multinucleated giant cells in giant cell granuloma are formed by cell fusion of capillary pericytes. In our present study we tried to analyze cell function and activity by histologic, histochemical, and electronmicroscopic examination of giant cells. Lysosomal enzymes such as acid phosphatase and amino-peptidase were found in giant cells which is in agreement with former work. By their lysosomal system giant cells are proved phagocytic. In addition, giant cells being localized at trabecular surfaces of newly formed woven bone may develop osteoclastic functions. The enzymatic and functional resemblance of giant cells and multinucleated osteoclasts points to the possibility of a similar cytogenesis of both cell types.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 371 (1976), S. 219-226 
    ISSN: 1432-2307
    Schlagwort(e): Canine mammary gland ; Mixed tumor ; Myoepithelial cells ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Es wurden licht- und elektronenmikroskopisch Spindelzellen fischzugartiger Verbände in 19 Mammamisehtumoren von Hündinnen untersucht. Die elektronenmikroskopischen Befunde sprechen dafür, daß es sich bei den spindeligen Tumorzellen meist um Zellen myothelialen Ursprungs handelt. Es wurden jedoch auch spindelzellige Verbände gefunden, die aus Fibroblasten bzw. Pibrocyten bestehen. Im lichtmikroskopischen Bereich ist eine sichere Unterscheidung nicht in jedem Fall möglich.
    Notizen: Summary Spindle cells of myomatous formations of 19 canine mixed mammary tumors were studied by light and electron microscopy. The EM findings indicate that the spindleshaped tumor cells are mostly of myoepithelial origin. However there were also formations of spindle cells which consisted of fibroblasts or fibrocytes. By light microscopy they are not always clearly distinguishable.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 370 (1976), S. 163-175 
    ISSN: 1432-2307
    Schlagwort(e): Central giant cell granuloma ; Histogenesis ; Histochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bisherige Untersuchungen an zentralen Riesenzellgranulomen des Gesichts-Kieferbereiches haben die Histogenese dieser tumorähnlichen Knochenerkrankung nicht klären können. Wir untersuchten daher zwei bioptisch gesicherte zentrale Riesenzellgranulome unter dieser Fragestellung histochemisch und elektronenmikroskopisch. Histochemisch findet sich eine enge Enzymverwandtschaft zwischen den mehrkernigen Riesenzellen und den Pericyten der Kapillaren, die das Granulom dicht durchsetzen. Elektronenmikroskopisch zeigen sich typische Membranphänomene der Zellfusion zwischen den mehrkernigen Riesenzellen und den Pericyten. Die für das Granulom charakteristischen mehrkernigen Riesenzellen entstehen daher durch Zellfusion aus den Pericyten, die als ihre Stammzellen angesehen werden müssen. Da die Pericyten das Granulom auch in Form zahlreicher blinder Kapillarsprossen durchsetzen, erklärt sich die Entwicklung einer Vielzahl von Riesenzellen. Die Ursachen, die diesem Verhalten der Pericyten aetiologisch zugrunde liegen, sind unbekannt. Ob die Cytogenese der Riesenzellen des zentralen Riesenzellgranuloms Modellcharakter hat und analog auch für die Entwicklung von Riesenzellen in anderen Gewebsneubildungen oder für die Enstehung der mehrkernigen Osteoclasten gilt, muß weiteren Untersuchungen vorbehalten bleiben.
    Notizen: Summary Until now numerous studies on central giant cell granuloma of jawbones have not been able to reveal the histogenesis of this tumourlike lesion. The aim of the present investigation in two surgically proven cases was to study this question by means of histochemical and electron-microscopic methods. Rather similar histochemieal properties were shown in giant cells and pericytes of capillary sprouts penetrating the granuloma. Cell fusion occurred between both cell types as was observed by electron microscopy. The process of cell fusion is defined by characteristic interdigitations of cell membranes. Therefore pericytes are believed to be the stem cells of multinucleated giant cells in giant cell granuloma. The abundance of giant cells usually occurring in the granuloma might be explained by plenty of capillary sprouts made up by clusters of pericytes. The factors inducing the pericytic cell fusion process are still unknown. The question arises whether cytogenesis of giant cells in giant cell granuloma might be similar in other giant cell lesions or even in the development of multinucleated osteoclasts.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 372 (1976), S. 205-226 
    ISSN: 1432-2307
    Schlagwort(e): Breast ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The fine structure of the terminal ductal-lobular unit (TDLU) of the normal, resting female breast is described. Tissue used conformed to strict criteria for normal. 4 distinct cell types, were observed, epithelium, myoepithelium, macrophages and lymphocytes. A gradation in structure, especially of myoepithelium, was found between the ductule tip and intralobular duct, apparently reflecting the age and function of each region. Cilia originating from the myoepithelial cells are possibly sensory in function. Epithelial vesicular inclusions may represent minimal secretory activity, transport of material across the cell, or be lysosomal in nature. The capillaries in close contact with the delimiting fibroblasts of the epithelial-stromal junction (ESJ) are described and the zone designated the capillary-fibroblast junction (CFJ). The CFJ is conceived as a regulatory unit similar to the ESJ, and may contribute to dysplasia due to biochemical or functional alterations, or to disruption of the microvascular geometry.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 369 (1976), S. 215-227 
    ISSN: 1432-2307
    Schlagwort(e): Kaposi's sarcoma ; Endothelial cells ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. Das wesentliche histologische Substrat des M.K. ist charakterisiert durch eine Proliferation von Zügen spindelförmiger Zellen, durch zellig begrenzte Gefäßspalten und durch eine geringfügige zellulär-entzündliche Begleitreaktion. 2. Die Zellen, welche die Gefäßspalten begrenzen, vehalten sich wie Capillarendothelzellen. Sie zeigen eine starke alkalische Phosphatase-Reaktivität und eine deutliche Leucinaminopeptidase-Aktivität; sie enthalten typische Weibel-Palade Granula. 3. Die ultrastrukturelle Analyse der Tumorzellen läßt ferner gefäßsprossenartige Formationen mit und ohne Lumen erkennen, an deren Ausbildung in der Hauptsache wenig ausdifferenzierte Endothelzellen beteiligt sind. Daneben erscheinen fibroblastoide Tumorzellen die sich möglicherweise von den Perithelzellen herleiten lassen. 4. Typisch für M.K. sind Extravasation und Phagocytose von Erythrocyten mit intracytoplasmatischem Abbau und Einlagerung myelinartiger, an Schwannzellen erinnernde Figuren. 5. Folgerung: Der M.K. ist gekennzeichnet durch eine multifokale Neubildung kapillarartiger Strukturen mit einer progressiven sarkomatösen Entwicklung.
    Notizen: Summary 1. Histologically, Morbus Kaposi is primarily characterized by a proliferation of streams composed of spindle-shaped cells, by vascular slits lined by cells, and by a minor cellular inflammatory reaction. 2. The cells lining the vascular slits resemble endothelial cells and exhibit strong alkaline phosphatase activity and a clear leucinaminopeptidase activity. They contain Weibel-Palade bodies. 3. The ultrastructural analysis of the tumor cells shows a proliferative formation resembling capillary sprouts with and without lumina. The lumina are composed primarily of poorly differentiated endothelial cells. A second typical cellular component are fibroblast-like tumor cells possibly derived from perithelial cells. 4. Indicative of M.K. are also extravasation and phagocytosis of erythrocytes with intracytoplasmic decomposition, and storage of myelinlike structures somewhat resembling Schwannian-cells. 5. Conclusion: M.K. is characterized by a multifocal neoplasia of capillary like structures and by a progressive sarcomatous development.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 371 (1976), S. 199-217 
    ISSN: 1432-2307
    Schlagwort(e): Giant cell tumor of soft parts ; Histopathology ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The light-microscopic and ultrastructural findings in a case of so-called giant cell tumor of soft parts, localized at the dorsal side of the left foot of a 23-years-old male are described. An amputation of the lower extremity was performed and subsequently chemotherapy with adriamycin was given for 3 months. Despite the histology and cytologic malignant appearance and the evident vascular invasion, already present at the time of the first excision, the last known status 2 years later seems favorable. There are no pathologic lymph nodes in the groins and no signs of metastases on chest X-rays. From the electron-microscopic study no definite conclusion can be drawn as regards the histogenesis of this tumor. We feel, as do others, that many of the principal mononuclear tumor cells are poorly differentiated mesenchymal cells. Some of the neoplastic cells, however, show ultrastructural features suggestive of chondro- or osteoblasts (a well-developed r.e.r. containing electron-dense material; multiple Golgi complexes; masses of glycogen; interdigitating cell membrane villi; cytoplasmic filaments; an extracellular amorphous matrix). Some of the larger tumor cells have the submicroscopic aspects of histiocytes as described in osseous, cutaneous, or pulmonary lesions of the histiocytosis X group. As yet undetermined cytoplasmic inclusion bodies constitute another rare observation in our material.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Journal of cancer research and clinical oncology 86 (1976), S. 55-68 
    ISSN: 1432-1335
    Schlagwort(e): Rhabdomyosarcoma ; Rhabdomyoblast ; Cellular Differentiation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung In der vorliegenden Untersuchung werden die cytomorphologischen Merkmale eines embryonalen Rhabdomyosarkoms des Nasenrachenraumes bei einem 10 jährigen Jungen aufgezeigt. Aufgrund der Ultrastruktur lassen sich im Tumor 4 Zelltypen darstellen: 1. Undifferenzierte mesenchymale Tumorzellen mit großem, euchromatischem Zellkern und schmalem, organellenarmem Cytoplasma; 2. undifferenzierte Tumorzellen mit einem Netzwerk von Intermediärfilamenten (Durchmesser etwa 100 Å) im breiten Cytoplasma; 3. unreife Rhabdomyoblasten mit zunehmender Entwicklung spezifische Myofilamente (Myosin: 180–210 Å, Actin: 68–80 Å Durchmesser); 4. reife Rhabdomyoblasten mit Myofibrillen in sarkomerischer Gliederung (Sarkomerlänge: 1,8 μ). Die starken Glykogenablagerungen in einigen cytoplasmareichen Tumorzellen werden als Zeichen eines Degenerationsprozesses gedeutet. Die cellulären Entwicklungsstadien des embryonalen Rhabdomyosarkoms sind identisch mit dem Ablauf der Embryogenese sowie der Regeneration normaler quergestreifter Muskulatur. Daher bieten sich für die Entstehung des embryonalen Rhabdomyosarkoms zwei Denkmodelle an: 1. Entstehung des Tumors aus einer undifferenzierten mesenchymalen Tumorstammzelle und 2. Atypische Regeneration nach Schädigung der quergestreiften Muskulatur mit Übergang in ein autonomes Tumorwachstum. Die zweite Hypothese ist jedoch wenig wahrscheinlich, da bis heute weder morphologisch noch experimentell eine derartige Tumorentstehung nachgewiesen werden konnte und zudem ätiologisch gesicherte Faktoren zur Induktion von Rhabdomyosarkomen beim Menschen fehlen.
    Notizen: Summary An embryonal rhabdomyosarcoma of the nasopharynx of a 10 year old boy is analysed with light and electron microscopy. With regard to cell shape and cytoplasmic features the following four tumour cell types could be distinguished: 1. Undifferentiated mesenchymal cells with a big loosely packed nucleus and a small cytoplasmic rim with only few cell organelles; 2. Undifferentiated tumour cells with a broad cytoplasmic body which contains a dense network of nonspecific intermediate filaments with a diameter of about 100 Å; 3. Immature rhabdomyoblasts with randomly orientated specific myofilaments; 4. Fully differentiated rhabdomyoblasts with well developed myofibrils often showing a sarcomeric pattern. Glycogen deposits which were seen in great masses in many tumour cells were regarded to result from degenerative processes within the tumour. The cellular stages in the development of rhabdomyoblasts are basically identical to those known from the embryogenesis and regeneration of striated muscle. From these observations the two following developmental pathways are suggested: 1. Origin of the tumour from an undifferentiated mesenchymal cell; 2. Atypical regeneration of striated muscle which terminates in malignant progressive tumour growth. At present, the body of information about rhabdomyosarcomas supports the assumption of an origin from immature mesenchymal cells. Nevertheless, the second theory cannot be totally excluded.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 149 (1976), S. 155-171 
    ISSN: 1432-0568
    Schlagwort(e): Large intestinal epithelium ; Postnatal development ; Rat ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The principal cells of the surface of the cecum, the ascending colon, and the descending colon in postnatal developing rats were investigated using both light and electron microscopy. In rats 1 to 14 days old the ultrastructure of the surface principal cells in the cecum and ascending colon were characterized by apical tubulo-vacuolar systems and large supranuclear vacuoles similar to those in the absorbing cells of the neo-natal ileum as reported by Clark, 1959, and others. After about the 16th day, the special membrane system disappears from the principal cells of the proximal large intestine. On the other hand, in the descending colon, this special membrane system was absent from the cytoplasmic matrix of the epithelium. It is thought that the proximal portion of the large intestine together with the distal part of the small intestine actively participate in the absorption of protein molecules at least during the early postnatal period.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 149 (1976), S. 323-346 
    ISSN: 1432-0568
    Schlagwort(e): Oculomotor nucleus ; Ultrastructure ; Synapses ; Membrane apposition ; Motoneurons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure, of the somatic efferent portion of the nucleus of the oculomotor nerve was studied in four adult cats. The neuronal population is composed of neurons of variable size. A continuous pattern of morphological aspects is evident between the large neurons, which show abundant cytoplasm with well developed organelles and the small neurons which have a reduced amount of cytoplasm. The dendrites are generally smooth, with few short spines. Axo-somatic and axo-dendritic synapses are numerous. Synaptic boutons are also present on the axon hillock. The neuropil is characterized by the occurrence of small groups of dendrites which may be in direct touch with their membranes. Direct membrane appositions may also occur between neighbouring neurons and between the cell somata and tangentially running dendrites. Generally beneath the site of apposition there is accumulation of mitochondria, multivesicular bodies, coated vesicles and moderately dense amorphous material. The morphological features suggest the possibility of cellular interchanges at the sites of direct membrane apposition. Five types of synaptic boutons were recognized on the basis of their vesicular content, the presence of abundant filaments in the pre-synaptic bag, the occurrence of post-synaptic specializations. The, different synaptic types and their distribution are similar to those reported in the spinal motor nuclei. Many of the synapses make synaptic contacts with two or more post-synaptic elements. Axo-axonic synapses were also observed.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 34 (1976), S. 353-357 
    ISSN: 1432-0533
    Schlagwort(e): Normal pressure hydrocephalus ; Human cerebral cortex ; Ultrastructure ; Extracellular space
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A cortical biopsy was taken at the time when ventricular pressure was measured, or a ventriculo-atrial shunt placed, in 11 patients with Normal Pressure Hyprocephalus (N.P.H.), and was studied with the electron microscope. In 9 cases, a rather typical electron microscopic picture with marked increase of extracellular space in an otherwise normal cortical neuropil was observed. 2 patients did not exhibit this pattern and, coincendentally, did not benefit from the placing of the shunt. As a control, about 600 cortical biopsies that had been taken for other reasons were reviewed. In the group, there were only 3 cortices that had a pattern of increased extracellular space similar to the described in N.P.H. On review of the clinico-pathologic data of these cases, it was felt that all 3 probably represented cases of normal pressure hydrocephalus. It is concluded that the ultrastructure of the cerebral cortex is of at least nosological interest in the study of N.P.H.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 321-327 
    ISSN: 1432-072X
    Schlagwort(e): Claviceps purpurea ; Saprophytic ; Clavine alkaloids ; Ultrastructure ; Extended hyphae ; Blastospores
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Ultrathin sectioning of submerged mycelium of Claviceps purpurea Tul. producing clavine alkaloids revealed yeast-like budding resulting in asexual sporesblastospores. These deciduous spores were born by extended hyphal cells and retained the same ultrastructure of cell organelles. Both the extended hyphae and the blastospores resembled the cells of ergot sclerotial tissue. A surface culture of C. purpurea Tul. producing no alkaloids was used as a reference.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Archives of toxicology 35 (1976), S. 115-125 
    ISSN: 1432-0738
    Schlagwort(e): Cerium ; Microsomal enzyme inducers ; Pregnenolone-16α-car-bonitrile ; Estradiol ; Fatty liver ; Ultrastructure ; Triglycerides ; Cerium ; Arzneimittelmetabolisierende Enzyme ; Pregneno-lon-16α-carbonitril „PCN“ ; Oestradiol ; Leberverfettung ; Elektronenmi-kroskopie ; Triglyceride
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Nach Vorbehandlung mit Steroiden und mit nicht steroidartigen Substanzen (Pregnenolon-16α-carbonitril „PCN“, Dexamethason, Spironolacton, Phenobarbital), welche die arzneimittelmetabolisierenden Enzyme der Leber stimulieren, und nach Oestradiol, wurde die Sterblichkeit und die Lebertoxicität der weiblichen Ratte erheblich verändert. PCN, Oestradiol, Dexamethason senken die hepatischen Triglyceride wesentlich, jedoch erhöht Dexamethason die Sensitivität der Tiere für CeCl3 bedeutend. Spironolacton und Phenobarbital üben keine große Wirkung auf die Triglyceride aus. Licht- und Elektronenmikroskopie zeigten, daß die durch CeCl3 hervorgerufenen hepatocellulären Veränderungen durch PCN, Oestradiol und Dexamethason bedeutend verringert wurden. Die Steroide dürften die Verteilung und die Bindung des Metalles an das endoplasmatische Reticulum verändern, und somit diese Membranen vor Cerium schützen.
    Notizen: Abstract In female rats, the lethality and hepatotoxicity of cerous chloride (CeCl3) were significantly altered by pretreatment with steroidal and nonsteroidal compounds (pregnenolone-16α-carbonitrile “PCN”, dexamethasone, spironolactone, phenobarbital) that stimulate hepatic drug-metabolizing enzyme activity and by estradiol. PCN, estradiol, and dexamethasone considerably decreased hepatic triglycerides, but the latter steroid also greatly sensitized the animals to CeCl3 lethality. Spironolactone and phenobarbital similarly lowered the triglyceride level but not significantly. Light and electron microscopy indicated that the hepatocytic damage elicited by CeCl3 was decreased significantly by PCN, estradiol, and dexamethasone. The steroids may have altered the distribution and binding of the metal to the endoplasmic reticulum (ER) thus protecting these membranes against the effect of cerium.
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 108 (1976), S. 167-174 
    ISSN: 1432-072X
    Schlagwort(e): Red algae ; Gracilaria verrucosa ; Tumor-like formations ; Ultrastructure ; Viruses ; Endoplasmic reticulum ; Plastids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This paper deals with electron microscopic observations on cultivated plants of the marine red alga Gracilaria verrucosa which developed simple galls; also sea collected material, without galls, had been studied. The galls showed unusual but characteristic cell structures, caterpillar-like bodies, containing rows of fusiform bodies. These were found mostly in the cytoplasm near the plastids, in one case connected with the endoplasmic reticulum, occasionally even inside the nucleus, and are described here, as far as we know, for the first time. It does not seem probable that the caterpillar-like bodies represent mitochondria or bacteria, but the hypothesis that fusiform bodies are related to virus-like structures is discussed. The normal tissues as well as the gall tissue of the laboratory plants contained, besides plastids typical for the red algae, another type of plastids characterized by tubular thylakoids.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 108 (1976), S. 305-312 
    ISSN: 1432-072X
    Schlagwort(e): Nitrobacter agilis ; Chemoorganotrophic growth ; Acetate ; Formate ; Pyruvate ; Yeast extract-peptone ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract 1. After a resting period of up to 6 months cells of Nitrobacter agilis grow with acetate, formate, and pyruvate as carbon and energy source. Yeast extract and peptone were added to supply the organism with nitrogen and to meet possible vitamin requirements. 2. The length of the growth period depends on the substrate; it increases according to the following sequence: pyruvate, formate, acetate. The highest growth yield is observed with pyruvate, the lowest with formate. 3. O2 consumption is increased in the presence of substrates as compared to endogenous respiration. With pyruvate and acetate twice as much O2 is consumed, with formate 7 times, with yeast extractpeptone 10 times as much. 4. The ability of nitrite oxidation is largely preserved, except in cells grown with acetate or pyruvate in the presence of 0.015% yeast extract and peptone. Such cells have nearly no cytochrome a 1. Accordingly, the cytochrome spectra of nitrite oxidizers grown under chemoorganotrophic and lithoautotrophic conditions coincide qualitatively. 5. The nitrite oxidizing system is inducible. It is induced by nitrite but also by substances present in yeast extract and peptone. Cells grown on acetate and yeast extract and peptone (0.015%) require 3–4 weeks before they regain the ability to grow with nitrite. Cells grown chemoorganotrophically with the same substrates and yeast extract and peptone (0.15%) start growing with nitrite as energy source without a lag. 6. Cell size and form, distribution of storage materials, order and fine structure of double membranes are correlated with growth conditions.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 277-282 
    ISSN: 1432-072X
    Schlagwort(e): Nitrosococcus mobilis ; Ammonia oxidizing bacterium ; Morphology ; Ultrastructure ; Physiology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An ammonia-oxidizing bacterium was isolated from a sample of brackish water (North Sea, Harbour of Husum). It is a motile large coccus 1.5–1.7 μm in diameter. The extensive cytomembrane system occurring as flattened vesicles in the peripheral region of the cytoplasm and as intrusions into the center of the cytoplasm is to be emphasized as a characteristic mark of identification. The lithoauto-trophically growing bacterium turned out to be an obligate halophile. Because of its physiological and morphological properties, we assigned it to the genus Nitrosoccus and propose the name Nitrosococcus mobilis.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 109 (1976), S. 277-288 
    ISSN: 1432-072X
    Schlagwort(e): Ultrastructure ; Mucorales ; Piptocephalis ; Mycoparasitism ; Cokeromyces ; Yeastphase ; Appressorium ; Infection peg ; Penetration ; Haustorium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Infection of the mucoraceous host Cokeromyces recurvatus by Piptocephalis unispora was studied ultrastructurally, using a new technique involving yeast-phase cells of the host to obtain large numbers of infection sites for thin-sectioning. Morphologically, the haustorial apparatus was similar to that of fungi parasitic on higher plants, and comprised an appressorium, a neck region with a collar and a neck ring, and a lobed region surrounded by a sheath matrix enclosed in an extra-haustorial membrane. Penetration of the host by the infection peg probably involved both enzymatic degradation and physical pressure. Reaction of the host to infection is described and the results related to the theory of host infection by haustorial fungal parasites.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 108 (1976), S. 105-111 
    ISSN: 1432-072X
    Schlagwort(e): Ammonia oxidizing bacterium ; Nitrosovibrio tenuis ; Isolation ; Morphology ; Ultrastructure ; Physiology ; Taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An ammonia-oxidizing, autotroph growing, slender, curved rod was isolated from the soil of Hawaii. It is well distinguishable from any other nitrifying bacteria thus far described by their morphology. The cells are 1.1–3.0 μm long and 0.3–0.4 μm wide. They are motile by means of 1–4 subpolar to lateral flagella. In contrast to most of the ammonia-oxidizing bacteria the isolated vibrio is void of an extensive cytomembrane system. To categorize this not yet described species we propose to create the new genus Nitrosovibrio and to classify the isolated strain as Nitrosovibrio tenuis.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 393-396 
    ISSN: 1432-0533
    Schlagwort(e): Ceroid lipofuscinosis ; Juvenile or adult ; Protracted form ; Lipopigments ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Clinical and ultrastructural findings consisting of curvilinear and fingerprint residual bodies, in a protracted juvenile form of NCL are reported from a woman who died at the age of 35 years. Homochrony and homotypy of her brother's illness emphasize intrafamilial similarities within subgroups of lysosomal disorders.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 34 (1976), S. 237-253 
    ISSN: 1432-0533
    Schlagwort(e): Strabismus ; Extraocular muscles ; Hirano bodies ; Ultrastructure ; Luse bodies ; Leptomeres
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Thirty extraocular muscles (EOM) from 20 patients were evaluated by light microscopy (LM), electron microscopy (EM), and enzyme histochemistry (EZH). Twenty-one EOM were obtained from 13 patients with strabismus, 9 EOM from 4 patients undergoing eye surgery for other reasons and from 3 autopsy cases. One μm thick sections revealed marked variation in muscle fibre shape and size and in myofibrillar structure; also noted were small, hypertrophied, whorled, and ringbinden fibres. Dense and granular material in the central portion of some fibres and sarcomere disruption in 2–3 μm sections was observed. EZH revealed the absence of the classical mosaic pattern usually found in skeletal muscles. ATPase studies were inconsistent and did not correlate with the expected reciprocal activity of NAD-H diaphorase, particularly on the large fibres. Ultrastructural features consisted of vacuoles within myofilament bundles, “smearing” of Z bands, and “nemaline rods”. Occasional myelin figures and lipid-like droplets were observed in subsarcolemmal spaces, associated with scattered clusters of glycogen granules. Abnormal mitochondria and subsarcolemmal inclusions of dense and granular material were conspicuous. “Leptomeric” profiles, “Zebra bodies”, or “striated bodies” were noted in 8 EOM's, and an Hirano body was found in 1. The intramuscular nerves contained structures resembling “Luse bodies” in 7 cases. These observations suggest that EOM from individuals with and without strabismus possess unique structural characteristics suggestive of developmental and morphological disarrangement of contractile elements. Some of these changes might play a role in the pathogenesis of strabismus and in the development of clinical symptoms. These features are significantly different from striated skeletal muscle. Therefore the criteria used in the pathological evaluation and diagnosis of skeletal muscle disorders cannot be unequivocally applied to EOM investigations. These data establish the necessity to determine histological norms, ultrastructural patterns, and develop new enzyme histochemistry criteria for the evaluation of EOM. Only then can an acceptable comparison of EOM and skeletal muscle be made.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 159-181 
    ISSN: 1432-0533
    Schlagwort(e): Leprosy neuropathy ; Ultrastructure ; Angiopathy ; Basement membrane ; “Blood-nerve barrier”
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Radial or superficial peroneal nerve biopsies of 6 patients with tuberculoid or borderline-tuberculoid leprosy and 6 control nerve biopsies were examined by electron microscopy. Endoneurial blood vessels showed histopathology in all the leprosy patients. Changes, in particular, involved the basement membrane in postcapillary venules and venules. Multilayered parellel basement membranes, with collagen and ground substance, formed a thick coat (“hyaline zone”) around the vessels. It is suggested that the zone inhibits passage of nutrients and metabolites and, thus, contributes to or is the main cause of the local destruction of (unmyelinated) nerve fibres and the lack of nerve fibre regeneration observed in this type of leprosy. The perivascular zone, presumably, is produced by pericytes in response to defects in the “blood-nerve barrier” of endoneurial vessels. In granulomata of leprosy skin lesions, a perivascular zone was not present. The endothelium of endoneurial vessels, in affected nerves, generallywas normal. Occasionally, however, gaps and fenestrations were seen and there were histological indications that leakage of blood plasma had occurred through the gaps and through the basement membrane of the endothelium. Occlusion of endoneurial vessels was found only in the oldest patient and the degeneration of nerve fibres generally observed thus is considered not to be caused by ischaemia. Histopathology in epi-and perineurial vessels was definitely less pronounced than in endoneurial vessels.
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 85-90 
    ISSN: 1432-0533
    Schlagwort(e): Mitochondrial inclusions ; Mitochondria ; Peripheral ganglia ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Neuronal perikarya of peripheral ganglia contained unusual dense core mitochondria that were not seen in other cell types or tissues of the same individual. They were found in several patients autopsied with GM1-gangliosidosis and neuronal ceroid-lipofuscinosis. Previous observations on human sympathetic ganglia, obtained by biopsy, and our findings suggest that these dense core mitochondria might represent a rare but regular feature of neuronal perikarya in peripheral ganglia of man.
    Materialart: Digitale Medien
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  • 26
    ISSN: 1432-1106
    Schlagwort(e): Rat ; Hypoglossal nucleus ; Inhibited regeneration ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Electron micrographs of the left hypoglossal nucleus were quantitatively analyzed in adult rats 52 to 98 days after transection of the left hypoglossal nerve and implantation of the proximal stump into the already innervated ipsilateral sternomastoid muscle, a procedure which prevented the transected nerve from regenerating. Many presynaptic boutons with clear spherical synaptic vesicles and symmetrical synapses were lost from the injured perikarya and dendrites. Some perikarya and dendrites (and, rarely, boutons) became electron dense, and astrocyte or microglial sheaths partly surrounded them. Numbers of dendrite profiles in the neuropil decreased. These statistically significant effects persisted throughout the postoperative period, whereas after axotomy with unimpeded nerve regeneration, these features would have returned to normal by 84 days postoperatively. It was therefore suggested that their recovery depended upon successful regeneration and reconnection of the hypoglossal nerve with the tongue. Subsurface cisterns, and profiles containing unusual inclusions, were numerically normal 52 to 98 days postoperatively, so it was suggested that their early response and recovery after simple axotomy might be entirely dependent on nerve disconnection and not on nerve reconnection.
    Materialart: Digitale Medien
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Mycopathologia 59 (1976), S. 117-123 
    ISSN: 1573-0832
    Schlagwort(e): Ultrastructure ; Zygospore ; Mycorrhizal fungus ; Flaming crown
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The ultrastructural organization of the spores of the sporocarp of Endogone flammicorona was studied. Two types of organization are described. Initially the spore possessed a vacuolate protoplasm and was bound by two cell wall layers. The spore was surrounded by a hyphal mantle formed of a sheet of vacuolized hyphae with uniformly thin walls. Secondly, although the ultrastructural features of the spore appeared the same, it was now surrounded by a hyphal mantle with unevenly thickened walls (i. e., the so-called flaming crown) due to the gradual and irregular deposition of granules and lamellae. This crown gives the spore its most commonly observed morphological feature and is the preminent character employed taxonomically to speciate Endogone flammicorona Trappe & Gerdemann.
    Materialart: Digitale Medien
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 489-505 
    ISSN: 1432-0878
    Schlagwort(e): Fundus striati ; Cat ; Nine bouton types ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An attempt has been made to discriminate additional types of synapses than have been previously described in the nucleus accumbens septi of the cat, which can, according to Brockhaus (1942), justifiably be termed the fundus striati due to the fact that it possesses all of the morphological and some of the neurochemical features of the striatum. This was undertaken in order to correlate at least one type of synapse with each different afferent pathway. Nine distinct types of synapses could be differentiated electron microscopically: Type I: axo-spinous synapses with sparse, small, round vesicles which seemed to be the nigro-striatal endings (35%). Type II: axo-somatic or axo-dendritic en passant synapses containing small, round vesicles (3%). Type III: axo-spinous synapses filled with densely-packed, small, round vesicles displaying strong postsynaptic thickenings which seem to be corticostriatal (17%). Type IV: large axo-spinous synapses with densely-arranged, small, round vesicles contacting larger spines branching off a pedicle (9%). Type V: axo-somatic or axo-dendritic synapses containing large pleomorphic vesicles, probably axon collaterals (1%). Type VI: axo-somatic or axo-dendritic synapses with elongated small vesicles (20×45 nm) (3%). Type VII: large axo-somatic or axo-dendritic synapses filled by denselypacked, small, round vesicles (11%). Type VIII: large axo-somatic or axo-dendritic synapses containing loosely-arranged, small, round vesicles (8%). Type IX: axo-somatic or axo-dendritic synapses containing large, round vesicles in a translucent axoplasm (13%).
    Materialart: Digitale Medien
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 549-559 
    ISSN: 1432-0878
    Schlagwort(e): Hypothalamic-hypophysial-adrenal axis ; Rat ; Development ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The adrenal glands of decapitated and encephalectomized fetal rats were investigated electron microscopically and compared to those of normal intact fetal rats. Although the adrenal cortices did not show three zones (zona glomerulosa, fasciculata, and reticularis) on the 16.5th day of gestation when the decapitation or encephalectomy was carried out in utero, the zonation was recognized in fetuses operated on the 21.5th day of gestation. The same was true for normal control fetuses. However, cytoplasmic characteristics suggesting steroidogenesis in the cortical cells were reduced to various degrees in the encephalectomized or decapitated fetuses, especially in the latter ones. The change in cytoplasmic appearance was more conspicuous in the inner portion of the cortex. This result suggests that for the maintenance of normal adrenocortical function the hypothalamus may be indispensable even during the prenatal life of rats.
    Materialart: Digitale Medien
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 173 (1976), S. 401-406 
    ISSN: 1432-0878
    Schlagwort(e): Pars intermedia ; Ultrastructure ; Peroxidase ; Stellate cell
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary To study the penetration of protein from the blood into and through the pars intermedia of anurans, the electron-dense tracer, horseradish peroxidase (HRP), was injected into the vascular system of the frog, Rana pipiens. Pinocytotic vesicles were seen along plasma membranes of the stellate cells abutting the pericapillary spaces between the pars intermedia and pars nervosa. The HRP was seen within both the pericapillary spaces and these pinocytotic vesicles. In addition, the HRP was very prominent in the extracellular spaces between adjacent stellate and/or MSH cells and around nerve endings and thus, appeared to move from the vascular spaces and into the interior of the pars intermedia. Therefore, the poorly vascularized pars intermedia may have such a route for transfer of materials throughout the gland.
    Materialart: Digitale Medien
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 221-227 
    ISSN: 1432-0878
    Schlagwort(e): Glial Cells ; Cyclic AMP ; Differentiation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Modifications of cell shape induced in cultured newborn rat astroblasts by serum deprivation or dibutyryladenosine 3′–5′ monophosphate (dBcAMP) are described. Serum suppression modifies the adhesivity of the cells to the substrate, but this modification is not consistent with a true differentiation. The main ultrastructural feature of dBcAMP-treated astroblasts is the presence of an extensive system of 90 Å microfilaments, while control cells are relatively devoid of these structures.
    Materialart: Digitale Medien
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 172 (1976), S. 133-144 
    ISSN: 1432-0878
    Schlagwort(e): Cornea ; Nerves ; Rat ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the corneal nerves of the rat was studied in tissue fixed by immersion in and by perfusion with glutaraldehyde-containing fixatives. Of the four types of axonal terminal identified in the nerves, those with the features of adrenergic and cholinergic terminals were confined to the nerves at the limbus and were concentrated in the perivascular plexuses. The remaining two types of terminal were found on axons located in all parts of the cornea and on both intraepithelial axons and axons in the stromal nerves. Of these, one contained the numerous mitochondria which occur in the terminals of axons associated with known mechanoreceptors and the second contained variable and often small numbers of both clear and large dense-cored vesicles. While most of the mitochondria-containing terminals were seen in nerves located near the periphery, vesicle-containing terminals were numerous in all of the nerves, and especially in those in the avascular cornea. In material fixed by immersion in glutaraldehyde-paraformaldehyde, the vesicle-containing terminals appeared to be dilated, but in material fixed by perfusion there was little evidence of any increase in the diameter of the axons in the terminal regions. The structure of the terminals was compared with that of the terminals of axons identified in the nerves of the skin and the urinary tract and the differences in the vesicle content of the terminals to those reported in other studies of the corneal nerves was related to the use of different fixation procedures. The possibility that axons possessing such terminals are identical with the beaded axons and both the cholinesterase-positive and fluorescent axons demonstrated in light microscopical studies of the corneal nerves is discussed, and the widespread distribution of the axons in the cornea is equated with the hypothesis that they are afferent in nature and represent the peripheral receptors for pain impulses.
    Materialart: Digitale Medien
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  • 33
    ISSN: 1432-0878
    Schlagwort(e): Epididymis ; Rabbit ; Organ culture ; Androgens ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure of the corpus epididymidis of the rabbit has been studied following organ culture. Various modifications of tissue preparation and culture conditions were examined to obtain good maintenance of cellular integrity as well as to preserve sperm fertilizing ability. After 5 to 7 days in culture in the absence of hormonal support, the epididymal epithelium showed signs indicative of cellular regression. Such changes included shrinkage of the cells, loss of the border of stereocilia, decrease in smooth endoplasmic reticulum, and an increase in autophagic vacuoles. The presence of androgens in culture media prevented cellular regression to varying degrees, depending on the hormone utilized. With regard to maintenance of cellular integrity, potency of the androgens tested was as follows: 5α-dihydrotestosterone 〉= 3α-androstanediol 〉 testosterone 〉 3β-androstanediol. Addition of insulin to dihydrotestosterone-containing cultures resulted in no improvement in maintenance. Phagocytosis of spermatozoa by epithelial cells was observed in cultured tubules and the degree of spermiophagy was inversely proportional to successful maintenance of fine structural characteristics of epithelial cells. The morphological findings reported here correlate well with the fertilizing ability of spermatozoa from cultured epididymis as reported in an accompanying communication.
    Materialart: Digitale Medien
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  • 34
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 119-127 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Lactose (β-galactosidase) was attached to the inner surface of nylon tubing. Tubes of various lengths were used to bring about the hydrolysis of o-nitrophenyl-β-D-galactoside and of lactose in skim milk. The results with the former substrate were analyzed in the light of a theoretical treatment of Kobayashi and Laidler (Biotechnol. Bioeng., 16, 99, 1974), with the conclusion that the reaction is intermediate between diffusion-free and completely diffusion-controlled behavior. The results with skim milk show that with a single 46 m tube and continuous circulation, 90% of the lactose is removed within 20 hr. A battery of ten such tubes, with single passage, at a flow rate of 2 cm/sec, would remove more than 99% of the lactose in less than 40 min.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 35
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 145-165 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The applicability of the model derived by Ramanathan and Gaudy (Biotechnol. Bioeng., 11, 207, (1969)) for completely mixed activated sludge treatment holding the recycle solids concentration as a system constant was investigated using an actual industrial organic wastewater. Short-term experiments were conducted at various dilution rates (1/8, 1/6, 1/4, 1/2, 1/1.5 hr-1) for two recycle solids concentration values (5000 and 7000 mg/liter). The influent substrate concentration was maintained at 1000 mg/liter COD and the hydraulic recycle ratio, α, was kept at 0.3. It was found that for bottling plant (Pepsi Cola) waste-waters, a steady state with respect to reactor biological solids and effluent COD, at different dilution rates, could be attained, lending experimental evidence to the assumption that a steady state could be reached in developing the model and also affecting the applicability of the model in industrial organic wastewater. The reactor biological solids and effluent COD calculated from the model closely agreed with the observed values at dilution rates lower than 0.5 hr-1. Operation at dilution rates higher than 0.5 hr-1 will washout the biological solids from the reactor and the recycle substrate concentration will be apparent if the concentration of XR were not increased.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
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  • 36
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 209-215 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A covalently bound adduct of nicotinamide adenine dinucleotide (NAD) with alginic acid has been found to be enzymatically active and to undergo electrochemical oxidation or reduction without significant loss of its enzymatic activity. The preparation of the adduct itself (from NAD+, alginic acid, and 1-cyclohexyl-3-(2-morpholinoethyl)-carbodiimide metho-p-toluenesulfonate) is also accomplished with substantially complete retention of enzymatic activity. This adduct has been converted from the oxidized to the reduced form by controlled potential electrolysis using mercury and stainless-steel electrodes. This electrolytically produced NADH complex could be oxidized again to the enzymatically active NAD+ complex by enzymatic reaction with the proton acceptor, 2,6-dichlorophenol indophenol, as catalyzed by diaphorase. Using this electrolytic method with immobilized NAD, it is now possible to carry out redox reactions in which NADH is enzymatically oxidized to NAD+, with the simultaneous electrolytic regeneration of the reduced form, NADH, from the oxidized form, NAD+, produced in the enzymatic reaction.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 37
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1017-1021 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 38
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1001-1016 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A means to avoid the glucose effect in the production of baker's yeast from glucose and/or molasses in a fed batch culture by controlling the feed rate of fresh medium with an ad hoc measurement of the respiratory quotient, RQ, is presented. The feed rate is changed stepwise here such that the value of RQ ranges from 1.0 to 1.2 throughout the cultivation. Thus far, the specific growth rate based on the total cell mass and the growth yield obtained throughout are 0.24 hr-1 and 0.55 g cell/g glucose.Prior to the experimental run mentioned above, equations to predetermine the feed rate and concentration of glucose in the feed are derived from the mass balance of limiting substrates (glucose). Since values of either RQ or IO2 (QO2 x, oxygen consumption rate with respect to the total cell mass in the fermenter) can be measured quite easily and reliably, computer control of the fermentation in light of this information is discussed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 39
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1029-1032 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 40
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1091-1101 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The microbiological leaching of a chalcopyrite concentrate has been investigated using a pure strain of Thiobacillus ferrooxidans. The optimum leaching conditions regarding pH, temperature, and pulp density were found to be 2.3, 35°C, and 22%, respectively. The energy of activation was calculated to be 16.7 kcal/mol. During these experiments the maximum rate of copper dissolution was about 215 mg/liters/hr and the final copper concentration was as high as 55 g/liter. This latter value is in the range of copper concentrations which may be used for direct electrorecovery of copper. Jarosite formation was observed during the leaching of the chalcopyrite concentrate. When the leach residue was reground to expose new substrate surface, subsequent leaching resulted in copper extractions up to about 80%. On the basis of this experimental work, a flow sheet has been proposed for commercial scale biohydrometallurgical treatment of high-grade chalcopyrite materials.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 41
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1117-1124 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: In a previous study on the chemostat culture of Saccharomyces carlsbergensis, maximum invertase specific activity was observed at an intermediate dilution rate. A possible regulation mechanism, assuming there are simultaneous effects of induction and repression on two sites of the operator loci for invertase formation, is proposed which might account for the observed curve of the dilution rate effect.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 42
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1167-1170 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 43
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1145-1159 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Various flavins, FMN, FAD, and acriflavin, were immobilized to Sepharose using several different coupling methods. The only product stable enough to permit extended studies was acriflavin coupled to epoxy-substituted Sepharose. The nonenzymic oxidizing capacity towards NAD(P)H was investigated and a 25% specific activity, compared to that of free acriflavin, was observed. The reduced acriflavin was immediately auto-reoxidized in air and could thus be reused. It was shown that acriflavin-Sepharose preparations function as NAD(P)H oxidizing agents in a number of different dehydrogenase systems including lactate dehydrogenase (LDH), alcohol dehydrogenase (ADH), malate dehydrogenase (MDH), alanine dehydrogenase (alaDH), and glutamate dehydrogenase (GDH). The amount of expensive coenzyme necessary for high product formation of such systems was thereby markedly reduced.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 44
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976) 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 45
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1171-1173 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 46
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1331-1334 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 47
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1315-1323 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: An integrated processing scheme is described for the conversion of a cellulosic waste (newsprint) to sugars by enzymatic hydrolysis and then to ethanol and yeast by fermentation. The unconverted solids are burned to produce process energy requirements and surplus electrical power. Preliminary designs and cost studies are developed to provide a rough perspective on the potential economic feasibility of this method of cellulose utilization.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 48
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976) 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 49
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1335-1335 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 50
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1335-1335 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 51
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1351-1358 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Feather meal protein was prepared in granular form and used as a support for lactase using glutaraldehyde as the crosslinking agent. The support gave a high retention of activity and in column operation it yielded apparent half-lives from 50 to 100 days. Because of its gel-like consistency (water content of about 90%), there is some diffusional restricting of activity as indicated by the kinetic data of soluble and immobilized enzymes.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 52
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1479-1480 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 53
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1463-1472 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Lactoperoxidase catalyzes the oxidation of thiocyanate by hydrogen peroxide and an intermediary product is formed with antibacterial properties. The components of this system, with the exception of hydrogen peroxide, are present in milk. H2O2 may be introduced by means of enzymatic, generation and thus make the system complete. A two-enzyme system consisting of β-galactosidase and glucose oxidase has been developed for this purpose. The coupled enzyme reaction is shown to work with high efficiency at the neutral pH of milk although the enzymes as such, particularly lactases suitable for immobilization, have optimal activities at much lower pH values. The results indicate that the lactoperoxidase system may in this way be employed to inactivate bacteria present in milk.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 54
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1497-1506 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A chemostat in which mammalian cells can be raised in continuous suspension culture is described. It is constructed from commercially available parts. This apparatus has the advantage over earlier models in that the medium can be pumped off free of cells, thus suddenly increasing the cell concentration in the culture. The apparatus has been successfully used in studies on contact inhibition.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 55
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1517-1535 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Experiments were performed in a pilot scale 0.30 m3 conventional stirred-tank fermentor using water, air/water, and air/K2SO4 solutions. Both single- and two-stage impeller systems were investigated. Overall and tank-side coefficients for heat transfer from a 0.012 m diameter coil were measured for a range of impeller speeds and superficial gas velocities. Power input, bubble size, and gas hold-up were also determined. An analysis of the experimental results indicates that previously published correlations for single-phase heat transfer in stirred tanks (of the type: Nu = C(Re)α(Pr)β) are not applicable for single- or multiimpeller gas/liquid systems. The introduction of air alters the mixing pattern significantly, affecting both average and local tank-side heat transfer coefficients. Power input and gas hold-up are suggested as the major correlating parameters for the determination of tank-side heat transfer coefficients.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 56
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1751-1760 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A doubling of cellulase production by Trichoderma viride (QM9414) is possible by increasing the cellulose concentration in the medium from 0.75 to 2%, increasing the nitrogen concentration, and controlling pH during growth. A four-to fivefold increase in β -glucosidase is found with the higher cellulose concentration. Culture filtrates from 2% cellulose cultures can reduce the hydrolysis time in a practical saccharification to one-half that required by culture filtrates from 0.75% cellulose cultures.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 57
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1761-1775 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The amide bond at N-6 in succinyl-NAD was found to be more stable than in former accounts. Succinyl-NAD was coupled on polylysine to give a new polymer derivative of NAD, which retained at least 85% of the initial coenzymic activity even after dialysis for one week. The polymer derivative of NAD could be applied to a membrane reactor containing alcohol dehydrogenase and lactate dehydrogenase and lactate was continuously produced in a half-life of ten days.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 58
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1-14 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A well-mixed biological reactor with continuous addition of biological solids was subjected to sinusoidal variations in inlet substrate concentration. The phase lag between inlet and outlet concentrations increased with increasing frequency. The deviation of measured substrate concentrations from initial steady-state concentrations was observed to have a maximum near a frequency of 1 cycle per residence time. Measured concentrations of substrate and biomass in the reactor differed significantly from concentrations predicted by the Monod kinetic model.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 59
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 189-198 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Utilizing a chemostat with a dual nutrient limitation of nitrogen and phosphate, we examined the transient response of the culture following a pulse of one of the limiting nutrients (ammonia). This method provided quantitative evidence that cells can be grown under dual nutrient limitation. Furthermore, the pattern of response was consistent with the hypothesis that phosphate limitation restricts nucleic acid synthesis in the cell and that nitrogen limitation restricts protein synthesis. The net result is that under a phosphate limitation there is a restricted biosynthetic capacity which we feel is closely associated with the RNA content of the cell.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 60
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 217-237 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Gluconobacter melanogenus IFO 3293 cells capable of converting L-sorbose to L-sorbosone were immobilized in polyacrylamide gel. The preferred polymer composition for high activity and stability was determined to contain a total monomer concentration of 7.2% and 16.6% crosslinking agent. No significant differences in optimal conditions for conversion, e. g., pH and temperature, were found in comparison with free cell suspensions. However, in the absence of L-sorbose, the thermal stability of immobilized cells was lower. After the initial loss, the conversion activity of immobilized cells increased, possibly due to lysis, and this increase was related to the polymerization conditions and the incubation temperature for the L-sorbose conversion.The enzymatic activity and stability of the immobilized cells also depended on the physical form of the gel and the aeration levels. Addition of electron acceptors or addition of L-sorbosone to the medium reduced, while addition of neomycin, ampicillin, chloramphenicol, and tetracycline increased the stability of the enzymatic activity.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 61
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 975-986 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A semicontinuous press has been constructed for the disintegration of microorganisms and other biological material by freeze-pressing, i.e., pressure extrusion of frozen material through a narrow hole. The material to be freeze-pressed is frozen in the form of cylindrical rods, which fit into the pressure chamber and are extruded by a piston forced back and forth by means of a hydraulic pump. At a sample temperature of -35°C and a press temperature of -20°C, about 90% disruption is achieved in a single passage of undiluted baker's yeast (Saccharomyces cerevisiae, 270 mg/g) through the orifice of the pressure chamber. With this press about 10 kg of material can be freeze-pressed per hour.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 62
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1177-1178 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 63
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1179-1191 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A heat and caustic pretreatment process has been tested to determine the increase in gas yield that can be obtained from fermentation of organic municipal refuse. A treatment temperature of 130°C and a NaOH concentration of 3 g/100 g of dry solids resulted in the highest gas yield for the conditions tested. The probable increase in gas yield was 20% for the best conditions tested. The treatment procedure also substantially increased the rates of gas production. A high conversion efficiency is possible at much shorter reactor retention times with pretreatment than without pretreatment.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 64
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1275-1295 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A completely mixed anaerobic filter, in which the influent organic matter concentration is diluted with recirculated effluent, was found to effectively remove organic matter concentrations in high strength acidic wastewater, at a range of organic loadings and shock loads. Increases in organic loading had a substantial effect on the relative organic matter composition of the effluent and the magnitude of the fatty acid fraction showed a pattern inverse to that of the nitrogenous organics. A fixed film model was formulated which indicated that at high substrate concentrations the substrate removal rate is proportional to the square root of the substrate concentration and the specific area of the filter medium. A comparison of the biofilm model and the measured effluent concentrations tended to indicate that the substrate removal rate is primarily affected by substrate concentration, specific surface area, flow rate, and temperature of the unit.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 65
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1325-1329 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1297-1313 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Ethanol fermentation studies were conducted with Saccharomyces cerevisiae ATCC #4126, to determine the optimal conditions of oxygen tension and feed sugar concentration. In long-term continuous culture maximum ethanol production was found to occur at 0.07 mmHg oxygen tension and 10% glucose feed concentration. Preliminary process design and cost studies are developed for industrial scale fermentations to produce ethanol and torula yeast from sugars obtained by enzymatic hydrolysis of newsprint.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 67
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1371-1392 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The rate of heat evolution (kcal/liter-hr) in mycelial fermentations for novobiocin and cellulase production with media containing noncellular solids was measured by an in situ dynamic calorimetric procedure. Thermal data so obtained have proved significant both in monitoring cell concentration during the trophophase (growth phase) and in serving as a physiological variable in the fermentation process. The validity of this technique has been demonstrated by closing the overall material and energy balances.The maintenance energy in a batch fermentation can also be calculated by integrating heat evolution data. This integration method is applicable to a fermentation lacking a precise cell growth curve. The maintenance coefficient, obtained for the novobiocin fermentation by Streptomyces niveus, is equal to 0.028 g glucose equivalent/g cell-hr. The production of novobiocin in the idio-phase (production phase) also correlates well with the amount of energy catabolixed for maintenance and this results in an observed conversion yield of glucose to novobiocin of 11.8 mg of novobiocin produced per gram of glucose catabolized.A new physiological variable, kilocalories of heat evolved per millimole of oxygen consumed, has been proposed to monitor the state of cells during the fermentation. This method may provide a simple way to monitor on-line shifts in the efficiency of cell respiration and changes in growth yields during a microbial process.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 68
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1405-1412 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The enzyme tyrosinase (E.G. 1.14.18.1) has been immobilized in a polyacrylamide gel and intermittently assayed for enzyme activity over a period of 19 days using phenol as the substrate. The results of these studies indicate that the immobilized enzyme could be incorporated into a system to detect phenol and related compounds that are found in industrial effluents and as surface water contaminants.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 69
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1445-1454 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: α-Chymotrypsin and acid phosphatase have been immobilized on chitosan, a polyaminosaccharide, without using any intermediate reagent; the immobilized enzymes are active and their activity is much higher than for chitin-immobilized enzymes. The best pH conditions for operating chitosan columns have been determined and columns have been used to transform substrates in large amounts, with no decrease of activity or enzyme losses. Due to the nonconvalent interaction between chitosan and enzymes, the pure and active enzymes can be eventually recovered from the columns. The effects of metal ions, aldehydes, and salts are reported and discussed. Applications are foreseen in the food and biomedical sciences and industries.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 70
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1455-1462 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Saccharomyces cerevisiae was grown under aerobic and substrate-limiting conditions for efficient biomass production. Under these conditions, where the sugar substrate was fed incrementally, the growth pattern of the yeast cells was found to be uniform, as indicated by a constant respiratory quotient during the entire growing period. The effect of carbon dioxide was investigated by replacing portions of the nitrogen in the air stream with carbon dioxide, while maintaining the oxygen content at the normal 20% level, so that identical oxygen transfer rate and atmospheric pressure were maintained for all experiments with different partial pressures of carbon dioxide. Inhibition of yeast growth was negligible below 20% CO2 in the aeration mixture. Slight inhibition was noted at the 40% CO2 level and significant inhibition was noted above the 50% CO2, level, corresponding to 1.6 × 10-2M of dissolved CO2 in the fermentor broth. High carbon dioxide content in the gas phase also inhibited the fermentation activity of baker's yeast.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 71
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1557-1572 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Tower cycling fermentors for the production of single-cell protein from volatile substrates were studied. The mass transfer, mixing and circulation patterns, and residence time distribution (RTD) curves were investigated in these vessels. This study suggests that the tower cycling fermentors for volatile substrates fermentation may improve product yields and at the same time reduce the power consumption, thereby resulting in a significant increase in operating cost savings and capital profits. The results of this research further indicate a future potential for commercial scale tower cycling fermentors.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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  • 72
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1777-1792 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Since steroids are only slightly soluble in the aqueous solutions in which enzymatic reactions take place, it is difficult to obtain high effective concentrations per unit reactor volume when enzymes are used to catalyze steroid reactions. In order to obtain high effective concentrations in the present work, we have used small particles of a hydrophobic polymer, poly (dimethyl siloxane), as a reservoir for the steroid substrate and product. The activity of a bacterial hydroxysteroid dehydrogenase in a buffer solution declines much more slowly in the presence of those polymer particles than in the presence of a comparable amount of butyl acetate or ethyl acetate, the organic solvents used as steroid reservoirs in previous work with steroid transforming enzymes. When another substrate of the hydroxysteroid dehydrogenase is loaded into the polymer particles and the particles are suspended in an aqueous solution containing the enzyme and its cofactor, more product is formed that when a similar solution is emulsified with butyl acetate.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 73
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 1807-1810 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 74
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 15-35 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The criterion for the oxygen limitation of substrate uptake in microbial film fermenters is expressed in terms of diffusion coefficients, utilization coefficients, and the free solution concentrations of substrate and oxygen. It is proposed that the ideal film thickness in such fermenters is equal to the penetration depth of the limiting substrate. The ideal film thickness is calculated, in terms of the parameters contained in the criterion for oxygen limitation, for three separate kinetic rate expressions. It is found that for the air-glucose-microbe system a simplified kinetic rate expression can be used and the region of dependence on two substrates is shown to be very limited. This is not true for other systems. Maximum uptake rates are calculated for a range of concentrations. Finally, it is shown that the procedure used can be generalized to determine the limiting substrate in a multisubstrate system and to calculate ideal film thickness and uptake rates for any pair of substrates where the kinetics of substrate uptake are known for the individual microorganism.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 75
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 95-104 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The apparent activation energy of N-α-benzoyl-L-arginine-ethyl ester (BAEE) hydrolysis by immobilized trypsin varies with the bulk substrate concentration from its maximum value, comparable to that of the free enzyme, to considerably lower values. Thus, with a concentration change from 3 × 10-2 to 10-4 M the apparent activation energy diminishes from 9.5 to 4.5 kcal/mol. This experimental finding is interpreted to be due to Michaelis-type kinetics in a heterogeneous system, in one case reflecting the temperature dependence of the maximal enzyme reaction rate, in another case illustrating the diffusion limited overall reaction at low substrate concentrations. As a consequence it may not be feasible to operate a reaction at elevated temperatures in a high conversion range, since diffusion limitation may restrict the enhancement of the overall reaction rate. Some further data are given concerning the buffer effect on the reaction rate, which should occur due to its limitation by proton transfer in the buffer-free system.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 76
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976) 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 77
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 53-62 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A graphical method is outlined in order to calculate the conversion under combined intra- and extraparticle transport limitations using the existing effectiveness factor charts for intraparticle diffusion.This method is applied to the case of an immobilized enzyme, assuming that the kinetics are of the Michaelis-Menten type.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 81-94 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Escherichia coli B, Escherichia coli MRE 600, Escherichia coli K 12-3300, Pseudomonas fluorescens, and Aerobacter aerogenes were grown exponentially in a bench-scale fermentor to cell concentrations in the range of 20 to 41 g dry cells/liter at 30°C and 30 to 55 g dry cells/liter at 25°C. The high cell concentrations were achieved in a growth system previously described for growth of Escherichia coli W (Biotechnol. Bioeng., 16, 933 (1974); ibid. 17, 227 (1975)). Various enzyme activity levels in the high-concentration cells were compared to those in cells grown in conventional low-density cultures. No significant differences were found. The culture supernatants were found to be essentially free of high-molecular weight metabolic or cell lysis products. Yield constants for glucose, nitrogen, oxygen, and phosphorus were also determined in the dense cultures and some of their relations to the growth conditions are discussed.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 79
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 133-139 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 5 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 80
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976) 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 81
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 37-51 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Little is known about techniques for applying untreated microbial cells containing enzymes directly to industrial processes as a biocatalyst. The kinetic behavior of α-galactosidase-containing spherical pellets which are formed naturally under given conditions in a submerged culture of Mortierella vinacea was studied on the hydrolysis of PNPG (p-nitrophenyl-α-D-galactopyranoside). The effect of intraparticle diffusion on the overall reaction rate was assessed by the use of an effectiveness factor, which was calculated by the approximate solution to the equation derived from the mass balance within a pellet. The experimental effectiveness factors were found to be represented as a single function of the modified Thiele modulus, including such parameters as pellet size, enzyme concentration in the pellet, and substrate concentration. As the diffusional effect became more significant, the marked substrate inhibition as seen for a five enzyme disappeared gradually. The effect of product inhibition on the pellets was much weaker than that for a free enzyme at a given substrate concentration. In the region of diffusion controlled reaction, it was found that the rate is proportional to the square root of the enzyme concentration in the pellet. In addition, similarly to what was reported previously for a free enzyme, the reaction in a batch system was found to be approximately representable as simple first-order kinetics in which the rate constant was dependent on the initial substrate concentration.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 82
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 105-118 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Trypsin was covalently immobilized on porous glass in the presence and absence of a specific substrate and reacted in various organic solvents of different dielectric constants. Optimum solvent concentration, pH profile, Km(app), Vmax(app), productivity versus temperature, activity, and reaction rates were determined. Reaction rates of six lysyl dipeptides were compared. Crystalline trypsin was dansylated for studies by nanosecond fluorescence techniques to determine the effects of introducing high concentrations of organic solvents on the molecule. The results indicated that greater reaction rates were observed with dipeptides having more acidic carboxyl terminal groups. The data also indicated that greater reaction rates were observed in higher concentrations of solvents of lower dielectric constants. Nanosecond fluorescence spectroscopy of trypsin in high concentrations of a low dielectric constant solvent indicated major dehydration even though maximal enzyme-activity was achieved under these conditions.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 83
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 141-142 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 84
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 179-187 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The glucose oxidase and catalase activities immobilized to the γ-aminopropyltriethoxysilane derivative of nickel-impregnated silica alumina was controlled by several factors. The most important of these was enzyme concentration. In constructing the dual immobilized enzyme catalyst, competition between the two enzymes for available binding sites was observed. The order of addition of the various reactants during immobilization was also important. Higher glucose oxidase activities were immobilized when glutaraldehyde was added concurrently with the enzyme, while maximal coupling of catalase occurred if glutaraldehyde was first added to react with the amino derivative of the silica alumina support, excess reagent washed away, and then the catalase added. Bovine serum albumin, which aids in the crosslinking of glucose oxidase, hindered the coupling of the enzyme to the support particles.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 85
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 239-252 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Monod's model is often assumed to describe the kinetics of feeding of a protozoan population on a bacterial population in a chemostat. An earlier study (J. L. Jost et al., J. Bacteriol, 113, 84 (1973)) of the feeding of Tetrahymena pyriformis on either Escherichia coli or Azotobacter vinelandii found that this model correctly predicted the occurrence of sustained oscillations of population densities but made predictions of minimum bacterial population densities that were much smaller than those observed. The earlier study removed the discrepancy between the model and data by replacing Monod's model with a different model. It is shown in the present study that the discrepancy can be explained equally as well if Monod's model for the feeding relation is retained and if, in addition, growth of bacteria on the chemostat walls is allowed for in the model equations.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 86
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 269-272 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 87
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 273-279 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 88
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 285-286 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 89
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 281-284 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 90
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976) 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 91
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 289-295 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: The influence of pH and temperature on the substrate yield coefficient for growth of Saccharomyces cerevisiae in a chemostat under limited organic substrate conditions was studied.Mathematical analysis of the substrate yield coefficient as a function of pH and temperature in the near-optimal area was made. It was shown that the location of pH and temperature optima were independent of each other. The maximum substrate yield coefficient had the following coordinates: pH = 4.1, temperature = 28.5°C.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 92
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 297-309 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Cells of Candida utilis grown in a single-stage chemostat at D = 0.05, 0.1, 0.25, and 0.35 hr-l were separated into a fraction of scar-bearing mother cells and a fraction of scar-free daughter cells. The scar-free cells were transferred into small batch cultures where the length of the maturation phase, changes in length and width of cells, specific growth rate, and specific rate of RNA and protein synthesis were examined for 5 hr. The daughter cells grown at D = 0.05 hr-1 were very small at the moment of separation from the mother cells (about one-third of the mother cell). Their maturation phase (in a batch culture), at the beginning of which they attain the specific growth rate approaching the μmax of the strain used, lasts for 3 hr. On the other hand, daughter cells grown at D = 0.35 hr-1 are almost the same size as the mother cells at the moment of separation. After transfer to a batch culture they begin to bud almost immediately. Similarly, in their other morphological and physiological parameters they differ strikingly from immature daughter cells which are formed at low specific growth rates. The importance of these differences from the point of view of mathematical modeling of growth processes is discussed.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 93
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 311-332 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Grazing of the ciliate Colpoda steinii on the blue-green alga Anacystis nidulans has been studied in batch and chemostat type laboratory cultures. Growth of the populations, grazing of the ciliates on the algae, hydrodynamic washout of the populations (in chemostat cultures), encystment of Colpoda, and transfer of cysts from the liquid culture to the vessel wall and their attachment thereto were all found to have significant effects on the dynamics of this system. In addition, reinoculation of the liquid with ciliates excysted from the wall and with algae detached from the wall may be important. The interaction of all of these processes produces quite complex dynamical phenomena which at present cannot be predicted by a model. The results obtained differ from those found earlier for feeding of ciliates or slime mold amoebas on bacteria in that steady states of coexistence, rather than sustained oscillations, were exhibited by the present system.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 94
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 333-348 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Experiments on the grazing of the ciliate Colpoda steinii on the blue-green alga Anacystis nidulans showed, among other things, that declines of the algal population initiated by grazing often continued for several days after grazing pressure had been released. In addition, long lags were observed when this alga was inoculated into sterile culture medium. Evidence presented in this study indicates that both phenomena were due to cellular damage caused by exposure of algal cells to a sudden increase of light intensity (“light shock”). The occurrence of light shock appeared to exert a destabilizing influence on the grazing relation between Colpoda and Anacystis.
    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, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 349-362 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Enzymes are generally sensitive to temperature changes. Porous glass particles used for glucoamylase immobilization are poor thermal conductors and a non-uniform temperature distribution can conceivably develop in a packed bed reactor of immobilized glucoamylase on porous beads. This study was made to determine experimentally the temperature and concentration profiles in an immobilized glucoamylase column. This work provides a procedure for examining possible heat effects on reactor column performance in enzyme applications.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 383-387 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A proposed substrate inhibition model (M. C. Tseng and M. Wayman, Can. J. Microbiol., 21, 994 (1975)), (1)\documentclass{article}\pagestyle{empty}\begin{document}$$\mu = \mu _{\max} S/\left[{K + S} \right],{\rm when}S 〈 S_\theta $$\end{document} (2)\documentclass{article}\pagestyle{empty}\begin{document}$$\mu = \mu _{\max} S/\left[{K + S} \right] - i\left[{S - S_\theta} \right],{\rm when}S 〉 S_\theta $$\end{document} derived from yeast growth rates has been applied to data for bacterial growth: Pseudomonas methanica grown on methanol and Arthrobacter AK19 grown on n-butanol. The model represents the experimental data very well.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 389-413 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Partially purified glucose isomerase from a Streptomyces species was immobilized on porous glass particles and studied for various characteristics concerning its use as an industrial catalyst. The activities were investigated in relation to the reaction parameters and the enzyme deactivation was studied systematically under various reaction conditions. The half-life of the immobilized enzyme was found to exceed 200 days at 50°C. The rate equation of the reversible glucose ⇄ fructose reaction was derived and the kinetic constants were determined. The rate equation was found to be in good agreement with experimental data for both forward and reverse reactions. The degree of diffusional effects was experimentally measured and theoretically analyzed.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 363-382 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Five cell lines (BSC-1, CHO, Balb/c 3T3, HeLa, and KB) have been grown in serum-free media for several months with regular schedules of media changing and subculturing. The medium found to be successful in all cases was MEM-α (without the ribosides and deoxyribosides) supplemented with 1% bactopeptone, although simple MEM [minimum essential medium (Eagle)] with bactopeptone (BP) gave fairly good growth in the case of BSC-1 and 3T3 cells. The addition of insulin was necessary for CHO, 3T3, HeLa, and KB cells. Only the BSC-1 cells grew exclusively as a monolayer in the serum-free systems, the CHO, HeLa, and KB cells growing as stationary suspensions and the 3T3 cells growing as a combination of monolayer and suspension depending on the age of the culture and the nature of the growth surface. SV40 was produced in BSC-1 cells grown and infected in the MEM-α, bactopeptone medium and adenovirus-2 was produced in spinners of HeLa and KB cells grown in MEM-α, bactopeptone, PVP-360, and insulin. The yield of virus and infectivity of the viruses produced were about the same as those produced in conventional serum-containing systems.
    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, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 421-424 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 415-420 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A series of baker's yeast continuous cultivations were made using different intensities of aeration. The experimental conditions were such as to eliminate the effects caused by high glucose concentrations in the medium on the formation of enzymes. The variation in activity of several enzymes was investigated and distinct changes were noted. The activities of hexokinase and alcohol dehydrogenase characterize the actual rate of glycolysis in yeast, the same being true, in part, for pyruvate decarboxylase. The activity of phosphofructokinase is nearly insensitive to the oxygen level at normal tensions. The activity of the cell to the phosphofructokinase can be limited in anaerobic conditions by its scarcity. The insensitivity of glucose-6-phosphate dehydrogenase to the oxygen tension together with its low activity suggests that this enzyme plays primarily a biosynthetic role and that the function of the pentose phosphate pathway as an energy-producing route is negligible.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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