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  • 1980-1984
  • 1975-1979  (302)
  • 1976  (302)
  • Biochemistry and Biotechnology  (174)
  • Electron microscopy  (128)
  • Nuclear reactions
Materialart
Erscheinungszeitraum
  • 1980-1984
  • 1975-1979  (302)
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 369 (1976), S. 181-190 
    ISSN: 1432-2307
    Schlagwort(e): Cerebral hemorrhage ; Cerebral artery disease ; Plasmatic arterionecrosis ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An electron microscopic study of the intracerebral arteries from 9 hypertensive cases was performed in order to elucidate the morphogenesis of the plasmatic arterionecrosis which was considered to be the direct cause of hypertensive intracerebral hemorrhage. In the preceding stage of the arterial lesions, marked necrosis of medial smooth muscle cells and increase of basement membrane-like substance in the intima and media were observed. The lumina of these arteries were slightly dilated. The dilatation and hemodynamic factors were supposed to cause endothelial injury resulting in blood plasma insudation into the intima through the opened spaces between endothelial cells. The insudated blood plasma dispersed and dissolved the basement membrane-like substance, collagen and elastic fibers in the arterial wall, leading to the development of the plasmatic arterionecrosis.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 370 (1976), S. 141-150 
    ISSN: 1432-2307
    Schlagwort(e): Angiotensin ; Catecholamine ; Strophanthin ; Rat heart ; Myocardial necroses ; Optical microscopy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei der Ratte nehmen die durch Angiotensin induzierten Herzmuskelfasernekrosen (75 mg/kg s.c. und i.p.) unter Strophanthin-Praemedikation (2 × 10−2 mg/kg i.p.) an Zahl und Ausmaß ab. Darüberhinaus ändert sich der elektronenmikroskopische Befund: Die alleinige Gabe von Angiotensin bewirkt eine Vakuolisation der Mitochondrion und eine Dilatation des endoplasmatischen Reticulum ohne Alteration der Myofibrillen. Die kombinierte Gabe von Strophanthin und Angiotensin führt zu einer primären Zerstörung der Myofibrillen, ohne daß Mitochondrien und tubuläres System sichtbar verändert werden. Der Schutzmechanismus des Strophanthin wird im Sinne einer Ökonomisierung des Zellstoffwechsels bei relativer coronarieller Insuffizienz diskutiert, welche durch die starke vasokonstriktorische Wirkung des Angiotensin ausgelöst wird.
    Notizen: Summary Number and degree of angiotensin-induced heart muscle necroses in the rat (75 mg/kg body weight) are diminuished by premedication with strophanthin (2 × 10−2 mg/kg body weight). The electron-microscopic findings are also changed: the application of angiotensin only results in vacuolization of mitochondria and a dilatation of the endoplasmatic reticulum while myofibrils are unaltered. Angiotensin in combination with strophanthin has a direct destructive effect on the myofibrils without evident changes of the mitochondria and the tubular system of the heart. The protective action of Strophanthin on the heart muscle cell is discussed in the sense of an economization of the cellular metabolism under conditions of relative coronary insufficiency, induced by the vasoconstructive effect of angiotensin.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 370 (1976), S. 273-289 
    ISSN: 1432-2307
    Schlagwort(e): Bone marrow biopsy ; Hairy cell leukemia ; Differential diagnosis ; Myelofibrosis ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In 24 patients with hairy cell leukemia, histological and fine structural findings from biopsies of the bone marrow are reported and their validity is compared with other diagnostic procedures available. Diagnosis by light microscopy of anterior iliac crest biopsies obtained by the method of myelotomy is possible with a high degree of accuracy. The differentiation of hairy cell leukemia from other myelo- or lymphoproliferative disorders based on cytomorphology as well as patterns of growth is emphasized. Morphological differences between fibrosis in this entity and other lesions such as malignant lymphomas, Hodgkin's disease, osteomyelofibrosis and -sclerosis are emphasized. Electron microscopy of the bone marrow shows single fibroblastic cells with numerous slender cytoplasmic processes randomly dispersed among the hairy cells. These fibroblasts are probably responsible for the synthesis of the reticulin and collagen fibres in their surroundings. Moreover fine structure of the hairy cells demonstrates pinocytic activity but no apparent phagocytosis in contrast to the phagocytic reticulum cells (histiocytes, macrophages). In the bone marrow the precursor cells and the many immature forms of hairy cells exhibit an overall lymphocytoid appearance during their maturation, suggesting a lymphocytic origin.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1432-2013
    Schlagwort(e): Tissue culture ; Fluorescence histochemistry ; Electrophysiology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Irides from 3–5 day old rats have been grown 1–3 mm from superior cervical or lumbar paravertebral sympathetic ganglia in modified Rose chambers. The two muscles of the iris received distinctly different innervation patternsin vitro, and these were similar to those seenin vivo. Varicose, adrenergic fibres were consistently associated with the dilator pupillae rather than with the sphincter pupillae while excitatory, cholinergic junctions developed between the nerve fibres and the muscle cells of the sphincter but not the dilator. There was a lack of specificity shown by the sympathetic neurons during this innervation. Fibres from lumbar ganglia formed plexuses within the dilator similar to those formed by superior cervical fibres, and sympathetic, cholinergic fibres were able to substitute for the normal parasympathetic, cholinergic fibres in the sphincter.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1432-2307
    Schlagwort(e): Human heart ; Innervation ; Fluorescence histochemistry ; Electron microscopy ; Catecholamines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The existence of both adrenergic and cholinergic innervation of the atrial myocardium of the adult human heart was demonstrated by means of fluorescence induced by formaldehyde or glyoxylic acid and by electron microscopy. The adrenergic fluorescing axons (1) followed the course of blood vessels as typical perivascular nerve plexuses, and (2) formed a three-dimensional fairly dense nerve net obviously not related to the blood vessels. The varicosities frequently came into close apposition on myocardial cells. Several types of nerve terminals were differentiated at electron microscopy: (1) an “adrenergic” type containing small (diameter 450–700 Å) dense-cored vesicles and usually (in various proportions) small “empty” and/or large (900–1500 Å) dense-cored vesicles, (2) a “cholinergic” type containing small (ca. 500 Å) “empty” vesicles and occasionally also some large (mean diameter ca. 1200 Å) dense-cored vesicles, (3) a “pale” type containing only a few or no vesicles, (4) a “disintegrated” type containing degenerated mitochondria, autophagic vacuoles, and occasional normal-looking mitochondria, (5) nerve terminals containing a large number of mitochondria in addition to varying vesicle populations, and (6) a (possibly baroreceptive type of) nerve terminal containing myelinlike lamellated structures. The “disintegrated” and the “pale” types of nerve terminals possibly represent different stages of axonal degeneration, or may correspond to diminution in the transmitter substance concentration under certain pathophysiologic conditions, respectively. Nerve terminals crowded with mitochondria may be sensory and involved in mechano-or chemoreceptive functions. In preliminary experiments convincing evidence was obtained that the glyoxylic acid-induced fluorescence histochemical method will be suitable for comparative studies on (human) clinical specimens, e.g., for analyzing the degree of the functional activity of the intrinsic adrenergic innervation of the myocardium under various pathophysiologic conditions. The modification which appeared most appropriate for such studies is described in detail, and is proposed for use as a standard method in other similar or related studies on human clinical series. The essential criteria for analyzing the specimens at fluorescence microscopy are suggested as well.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 371 (1976), S. 251-263 
    ISSN: 1432-2307
    Schlagwort(e): Human liver ; Electron microscopy ; Stereology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The stereologioal model and the base-line data of normal human liver needle biopsy-specimens are presented. Four reference systems were introduced: 1 cm3 of liver tissue, 1 cm3 of hepatoeyte, 1 cm3 of hepatocytic cytoplasm and the volume of an average “mononuclear” hepatocyte. The sampling was done at three levels of magnification (1,000 ×, 5,000 × and 10,000 ×). A lobular differentiation was not considered. The baseline data show strikingly small variations (s.e. less than 10%) within the individual biopsy specimen and within the group of four biopsies. There is no principal difference between human beings presented here, rats, mice and dogs. Only the mean individual volume of human hepatocytes is clearly larger than in rodents. The problems and limitations of stereological work on liver biopsy specimens are discussed.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Virchows Archiv 371 (1976), S. 273-282 
    ISSN: 1432-2307
    Schlagwort(e): Nasopharyngeal angiofibroma ; Fibroblast ; Vascular cells ; Fibromatosis ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An electron-microscopic study of 9 nasopharyngeal angiofibromas was performed in order to elucidate the ultrastructural characteristics. Stromal fibroblasts and proliferating cells of the microvasculature were found. The stromal fibroblasts were subdivided into 3 different groups: (1) “classical” fibroblasts, (2) fibroblasts with histiocytelike features, and (3) fibroblasts with myoid features. By proliferation the cells of the capillary vessels change into stromal cells. A particular pattern of nuclei and dense intranuclear granules is only found in stromal fibroblasts. Consequently fibroblasts as well as cells of the microvasculature contribute to the pool of tumor cells.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Archives of gynecology and obstetrics 220 (1976), S. 199-208 
    ISSN: 1432-0711
    Schlagwort(e): Rat ovaries ; Diabetes mellitus ; Alloxan ; ATP/ADP ; Lactate/pyruvate ; NADP/NADPH ; Glucose ; Protein content ; Hydrogen-coveying enzymes ; alkal. phosphatase ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Es wurde der Einfluß eines alloxan-induzierten Diabetes mellitus auf den Stoffwechsel und die Ultrastruktur juveniler Rattenovarien untersucht. Der Diabetes mellitus bewirkte folgende Änderungen imStoffwechsel: Abfall der Konzentration von ATP und NADPH, Anstieg des Lactat/Pyruvat-Quotienten über 40, Abfall des ATP/ADP-Quotienten unter 1, Aktivitätsminderung der wasserstoffübertragenden Enzyme G-6-DH, Isocitrat-DH, Malat-DH, Aktivitätszunahme der alkalischen Phosphatase, Erniedrigung des Proteingehaltes.Ultrastruktur: Nahezu vollständiges Verschwinden des rauhen endoplasmatischen Reticulums, Schrumpfung der Mitochondrien, Reduktion der cristae und Kondensation der Matrix. Das glatte endoplasmatische Reticulum bleibt unverändert, der Golgi-Komplex ist in seiner Ausdehnung reduziert. Leichte Extrahierbarkeit der Lipiddepots. Die Befunde sprechen für eine Hemmung der oxydativen Phosphorylierung sowie für eine Beeinträchtigung des Steroid- und Proteinstoffwechsels.
    Notizen: Summary Tests were carried out on the influence of alloxan-induced diabetes mellitus on the metabolism and the ultrastructure of ovaries of juvenile rats. The diabetes mellitus caused the following changes in themetabolism: reduction in the concentration of ATP and NADPH, increase in the lactate/pyruvate quotient to above 40, reduction in the ATP/ADP quotient to below 1, reduction in the level of activity of the hydrogen-conveying enzymes G-6-P-dehydrogenase, isocitrate dehydrogenase and malate dehydrogenase, increase in the level of activity of the alkaline phosphatase, reduction of the protein content. Ultrastructure almost complete disappearance of the rough endoplasmic reticulum, shrinkage of the mitochondria, reduction of the cristae and condensation of the matrix. The smooth endoplasmic reticulum remains unchanged, the extent of the Golgi-complex is reduced. Easy removal of the lipid deposits.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Anatomy and embryology 149 (1976), S. 123-148 
    ISSN: 1432-0568
    Schlagwort(e): Rat-placenta ; Gap junctions ; Electron microscopy ; Freeze-fracturing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The placental labyrinth of the chorioallantoic placenta of the rat was studied with transmission and scanning electron microscopy. Full-term placentas were investigated after perfusion fixation from the maternal and fetal circulation, including thin-sectioning and freeze-fracturing. The labyrinthal three-dimensional structure was found not to be trabecular but spongious lamellar. We propose a division of the lamellae into three groups—the first, second, and third order. The trophoblastic layers are described in detail, showing a cellular layer I and two syncytial layers II and III. Layer I is found to be fenestrated and highly permeable. Layers II and III are connected by extended gap junction areas. It is suggested that the gap junctions function as a molecular sieve and represent the limiting barrier in diaplacental transport of the choriollantoic placenta. Fetal capillaries are fenestrated and endothelial cells are connected by tight junctions. The functional significance of the morphologic findings is discussed.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1432-0533
    Schlagwort(e): Experimental malignant Schwannomas ; Organ culture ; Electron microscopy ; Differentiation ; Microtubules ; Basal lamina ; Perineurial fibroblasts
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The sequential electron microscopic features of six malignant nerve sheath tumors (three cranial and three spinal) induced in rats by transplacental ethylnitrosourea and maintained in organ culture systems were compared with those of a human acoustic Schwannoma similarly cultured. After 4 weeks in vitro, the malignant tumor cells often showed progressive elongation of their processes, with the development of an interdigitating pattern resembling that seen in well-differentiated Schwannomas. This was accompanied by an increase of microtubules. Basal lamina formation, less well-developed and less complete than in the benign Schwannoma in this study, was maintained in culture. Some explants demonstrated an increase in number and width of collagen fibrils, accompanied by a relative concomitant decrease of intercellular basement membrane material. The malignant tumor cells also showed numerous micropinocytotic vesicles and various junctional complexes, which are characteristic of perineurial cells. Since the origin of the experimental tumors from adult Schwann cells seems well established, this apparent contradiction is best resolved by the concept that Schwann cells and perineurial fibroblasts are functional variants of the same cell type.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 1-12 
    ISSN: 1432-0533
    Schlagwort(e): Cytoplasmic vacuole ; Oligodendroglia ; Brain edema ; Metastatic carcinoma ; Glioma ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Vacuolation of oligodendroglia, a new type of cytopathological change, has been described. The change is observed frequently at the perifocally edematous cerebral white matter adjacent to the metastatic lesions of carcinoma from the lung in all three cases examined. It is also present occasionally in association with astrocytoma. This condition is characterized by swelling of oligodendroglias due to numerous cytoplasmic vacuolations which contain the material identical with that of the extracellular edema fluid. In such cells, the nucleus is displaced and deformed by vacuoles but the nuclear chromatin and envelopes are arranged normally. By occupation of numerous large vacuoles the cytoplasm is divided into small areas, but the individual organelles are only minimally altered. The oligodendroglial vacuolation seems to be a phagocytic response to the edema fluid which contains proteinous macromolecules derived from blood-borne protein and necrotic material of brain tissue and neoplastic cells. The vacuolation may result in some oligodendroglial dysfunction in maintenance of myelin and probably be related with diffuse loss of myelin sheath in the longstanding brain edema secondary to neoplastic invasion. The vacuolated cells can be identified with light and electron microscopes in Epon-embedded sections of surgically removed tissue but not in paraffin sections.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 34 (1976), S. 329-338 
    ISSN: 1432-0533
    Schlagwort(e): Muscle pathology ; Target muscle fibre ; Targetoid muscle fibre ; Histochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A large number of target fibres is observed in a muscle biopsy from a patient with an acute flaccid paraplegia of the lower limbs due to a polyneuroradiculopathy of unknown origin. With the electron microscope up to 4 structural zones are seen in the target fibers. The histochemical and ultrastructural observations in this case, suggest that the “target fibre” phenomenon is due to a disturbed trophic influence of the nervous system.
    Materialart: Digitale Medien
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  • 13
    ISSN: 1432-072X
    Schlagwort(e): d-Ribulose 1,5-diphosphate carboxylase ; Oxygenase activity ; Quaternary structure ; Electron microscopy ; Alcaligenes eutrophus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract d-Ribulose 1,5-diphosphate carboxylase has been purified from autotrophically grown cells of the facultative chemolithotrophic hydrogen bacteriumAlcaligenes eutrophus. The enzyme was homogeneous by the criteria of polyacrylamide gel electrophoresis. The molecular weight of the enzyme was 505000 determined by gel filtration and sucrose density gradient centrifugation, and a sedimentation coefficient of 18.2 S was obtained. It was demonstrated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis that the enzyme consists of two types of subunits of molecular weight 52000 and 13000. Electron microscopy on the intact and the partially dissociated enzyme lead to the construction of a model for the quaternary structure of the enzyme which is composed of 8 large and 8 small subunits. The most probable symmetry of the enzyme molecule is 4:2:2. Michaelis constant (K m ) values for ribulose 1,5-diphosphate, Mg2-, and CO2 were 0.59 mM, 0.33 mM, and 0.066 mM measured under air. Oxygen was a competitive inhibitor with respect to CO2 suggesting that the enzyme also exhibits an oxygenase activity. The oxygenolytic cleavage of ribulose 1,5-diphosphate was shown and a 1:1 stoichiometry between oxygen consumption and 3-phosphoglycerate formation observed.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 111 (1976), S. 175-183 
    ISSN: 1432-072X
    Schlagwort(e): Serratia marcescens ; (Phage tail) bacteriocin ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Genese eines phagenschwanzähnlichen Bacteriocins in Zellen des Gruppe A-bacteriocinogenen (bA+) Serratia marcescens-Stammer Nr. 16 wurde nach Mitomycin C (MC) Induktion elektronenoptisch untersucht. Dieses Bacteriocin (Gesamtlänge 117 nm) besteht aus einem hohlen Stift mit kontraktiler Scheide. Nach 60 min Induktion wurden in Dünnschnitten stäbchenförmige Bacteriocine identifiziert. Sie erscheinen in drei Aggregationsformen: 1. als hexagonale Einschlüsse, 2. als Bänder dicht nebeneinanderliegender Bacteriocine und 3. als Stapel von übereinanderliegenden Bacteriocinschichten, wenn nach 120 min Induktion ein Maximum von ca. 450 Bacteriocinen pro Zelle erreicht wird. Bacteriocine konnten nach der gleichen Induktionszeit von 60 min auch mit der “in situ lysis technique” nachgewiesen werden. Neben Bacteriocinen traten relativ selten und unregelmäßig auch Phagenköpfe auf. Die Stäbchenform teilungsfähiger Zellen blieb bis zum Auftreten von intracellulären Bacteriocinen erhalten. Ihre Umwandlung in geblähte, sphäroplastenähnliche Zellformen, die nach 120 min Induktion lysierten, war zeitlich korreliert mit Feinstrukturveränderungen der Zellwand.
    Notizen: Abstract The biosynthesis of a phage tail-like Bacteriocin by cells of the group A-bacteriocinogenic (bA+ Serratia marcescens strain no. 16 after induction with mitomycin C (MC) was examined electronmicroscopically. This bacteriocin (total length 117 nm) consists of a hollow core and a contractile sheath. At 60 min following induction, rod-like bacteriocin-partieles were identifiable in ultrathin sections. The particles were found to comprise three morphologically different forms of aggregation: 1. hexagonal inclusions, 2. contiguous, bank-like particles, and 3. staples of superimposed layers of bacteriocin particles. At 120 min after induction bA+ cells revealed maximally 450 bacteriocin particles. Similarly, the phage tail particles could be demonstrated with the “in situ lysis technique” at 60 min following induction. Occasionally, phage heads were demonstrable, but in no instance were complete phage particles discernible. Dividing cells of the bA+ strain of S. marcescens maintained their rod-form following induction with MC until intracellular phage tail bacteriocin particles were seen. However, at 120 min after induction, the swollen, sphaeroplast-like cells lysed, an event that could be correlated with fine structural alterations of the cell wall.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 108 (1976), S. 231-242 
    ISSN: 1432-072X
    Schlagwort(e): Phytophthora ; Penetration ; Eucalypts ; Roots ; Electron microscopy ; Appressoria ; Plugs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The mechanisms of penetration of Phytophthora cinnamomi Rands into seedling eucalypt roots were studied by light and electron microscopy. Culture grown seedlings of root-rot tolerant Eucalyptus st johnii and root-rot susceptible Eucalyptus obliqua were inoculated with both zoospores and mycelium. Zoospores encysted on roots of both species and the germ tubes penetrated without the formation of appressoria. Swellings, previously described as appressoria, were formed when the germ tube was slow to enter the host by intracellular penetration. Vegetative hyphae penetrated both inter- and intracellularly into the zones of root elongation and differentiation, often through root hairs. Evidence of hydrolysis of the host cell-wall at the point of penetration was observed in electron micrographs. Several hours after the germ tube penetrated the epidermis, a thick plug of amorphous material formed in the germ tube slightly below the level of the outer walls of the epidermal cells, sealing off the hypha within the root. Behaviour of zoospores and germ tubes and the mechanism of penetration were similar on both hosts. Micrographs do not suggest any kind of a hypersensitive reaction by the host cells during the early stages of infection.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 99-107 
    ISSN: 1432-072X
    Schlagwort(e): Piptocephalis unispora ; Mucorales ; Kickxellaceae ; Electron microscopy ; Germination ; Spore swelling ; Sporangiospore
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Germination of the sporangiospore of Piptocephalis unispora Benjamin, observed by means of light and electron microscopy, involved the formation of a new inner wall which became continous with the inner layer of the wall of the germ tube. The outer wall layer of the germ tube was continous with the original inner wall layer of the dormant spore. Preliminary details of appressorium structure were noted. Nutritional experiments indicated that sporangiospores required external sources of utilisable nitrogen and carbon compounds for maximal swelling and germ tube production. Limited development occurred when either nutrient was supplied singly. Comparison of germination of the asexual spore with that in other Mucorales, especially the Kickxellaceae, has been made, and the merosporangial status in P. unispora discussed.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 113-114 
    ISSN: 1432-072X
    Schlagwort(e): Achlya ; Electron microscopy ; Nuclear microfilaments ; Antheridia ; Mycology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This is the first report of intranuclear microfilaments within gametangial nuclei of oömycetous fungi. Longitudinal sections of four to six microfilaments were frequently observed in meiotic antheridial nuclei of Achlya ambisexualis. Each microfilament measured approximately 7–10 nm in diameter. Spindle tubules (25 nm in diameter) were also observed within some of the nuclei possessing microfilaments.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 167-182 
    ISSN: 1432-072X
    Schlagwort(e): Ectothiorhodospira mobilis ; Photosynthetic membranes ; Electron microscopy ; Isolation of membranes ; Structure of membranes ; Composition of membranes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The lamellar membrane stacks of Ectothiorhodospira mobilis were isolated and purified by a combination of lysozyme and osmotic shock treatment, followed by differential and density gradient centrifugation. Preparations of lamellar membranes were enriched at least 2.4-fold in the ratio of bacteriochlorophyll a to protein. Thin-sectioning, negative staining, platinumcarbon shadowing and freeze-etching were used to study the architecture of the membrane units. Both platinum-carbon shadowing and freeze-etching showed the outer surfaces of the isolated lamellar membrane stacks to be relatively smooth. Particles averaging 7 nm in diameter were seen on several faces following freeze-ctching. Non-polar amino acids amounted to 60% of the total amino acid composition. Lipids constituted 32% of the membrane dry weight. Phosphatidyl ethanolamine and diphosphatidyl glycerol were the major phospholipids. Fatty acids of 10–15 carbons represented a small fraction of both membrane and whole cell fatty acids. Monoenes constituted 36% of the total membrane fatty acids and 38.4% of the total whole cell fatty acids. The major fatty acids of both whole cells and purified membranes were C16:0, C18:1 and cyclopropane C19:0.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 109 (1976), S. 195-197 
    ISSN: 1432-072X
    Schlagwort(e): Cell wall ; Peptidoglycan ; Electron microscopy ; Bacillus subtilis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Isolated cell walls of Bacillus subtilis have a striated appearance in the electron microscope. The structure persists when teichoic acids are removed. It is inferred that the structure bears on the arrangement of the peptidoglycan chains.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 107 (1976), S. 313-320 
    ISSN: 1432-072X
    Schlagwort(e): Micrococcus radiophilus ; Micrococcus radioproteolyticus ; Bacterial cell walls ; Fine structure ; Electron microscopy ; Taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The radiation resistant bacteria Micrococcus radiophilus and M. radioproteolyticus were studied by thin sectioning and freeze-etching techniques and the two species were found to be similar in the fine structure. The only significant difference was in the appearance of the surfaces of the cell walls in freeze-etched preparations. Since the two species, together with M. radiodurans, possess a unique cell wall structure and a cell wall peptidoglycan, which is different from that of other micrococci and Gram-positive cocci, it is recommended that they be reclassified into a new genus.
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 108 (1976), S. 55-64 
    ISSN: 1432-072X
    Schlagwort(e): Bdellovibrio ; Spirillum ; Cell wall ; Bdelloplast ; Lipoprotein ; Peptidoglycan ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In both freeze-etched and critical-point dried preparations examined by transmission and scanning electron microscopy, respectively, the outer surfaces of the cells of Spirillum serpens VHL assume a wrinkled appearance 10–15 min after challenge by Bdellovibrion bacteriovorus 109D. This wrinkling effect is believed (on circumstantial evidence) to be caused by the bdellovibrio's disruption of the cell wall lipoprotein of the Spirillum. With the exception of those topological changes caused by wrinkling, the outer membrane of the Spirillum cell wall retains a normal appearance as viewed in freeze-etched preparations, even after the Spirillum cell has been converted into a bdelloplast. Although the peptidoglycan layer of the Spirillum cell presumably is weakened somewhat by the invading Bdellovibrio, evidence obtained from freeze-fractured preparations of Spirillum bdelloplasts suggests that the peptidoglycan remains as a discrete cell wall layer, even though the Spirillum cell wall apparently has lost much of its rigidity. That the peptidoglycan backbone remains essentially intact, even after the Spirillum cell has been entered by the Bdellovibrio, is supported by the observation that the soluble amino sugar content of the culture medium, as determined by chemical analysis, does not rise even 5.0 h after the association of the Bdellovibrio with the Spirillum has begun.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 109 (1976), S. 21-30 
    ISSN: 1432-072X
    Schlagwort(e): Electron microscopy ; Allomyces ; Gametes ; Fertilization ; Membrane fusion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The gametes and the process of fertilization were examined by light and electron microscopy in the lower eukaryote Allomyces macrogynus. Differences in gamete morphology included the overall larger size and the presence of a larger nuclear apparatus, along with the association of a side-body complex and many more mitochondria in the female gamete. In this species of Allomyces, fertilization was initiated by contact and fusion of specialized regions of the gamete plasma membranes resulting in a binucleate fusion cell surrounded by plasma membrane contributed by both partners. Following plasmogamy, nuclear fusion was initiated by multiple nuclear membrane contacts between adjacent outer membranes. Following inner membrane fusion, small nucleoplasmic bridges were observed which presumably fused with one another and resulted in a single bridge which widened, forming the mature diploid nucleus. After karyogamy, fusion of the nuclear caps did not always occur and zygotes with and without fused caps were observed. Coalescence of the nucleoli completed the events of fertilization, forming a zygote with a single nuclear apparatus (sometimes with two caps) and two flagella. These observations are discussed in relation to fertilization mechanisms and compared to fertilization in other organisms.
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Archives of gynecology and obstetrics 221 (1976), S. 277-287 
    ISSN: 1432-0711
    Schlagwort(e): Electron microscopy ; Endocrinology ; Pathology ; Testicular feminization ; Testis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Testicular tissue was investigated by electron microscopy in a case of testicular feminization. The seminiferous tubules were lined by spermatogonia and by Sertoli cells. Spermatocytic maturation was not observed. Leydig cells were numerous and contained well developed, abundant vesicular smooth-surfaced endoplasmic reticulum and large mitochondria with tubulovesicular cristae. Reinke crystalloids were absent. The ultrastructural findings were consistent with the assumption that Leydig cells were under adequate stimulation and were in a stage of active secretion. Hence, the results seem to indicate that testicular endocrine function was maintained in the studied case.
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 34 (1976), S. 183-197 
    ISSN: 1432-0533
    Schlagwort(e): Lewy body ; Electron microscopy ; Parkinsonism ; Dense core vesicles ; Catecholamines ; Mitochondrial inclusions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The Lewy body, a characteristic nerve cell inclusion in idiopathic parkinsonism, was examined by electron microscopy in the stellate ganglion, obtained from 9 patients at autopsy. Three main forms of Lewy bodies or Lewy body-related structures were demonstrated: A. Rare filamentous Lewy bodies, similar to Lewy bodies in the central nervous system. B. Granular Lewy bodies in nerve cell processes. C. Abnormal nerve cell processes, filled with heterogenous material. Large dense core vesicles were prominent in the last 2 forms. None of these abnormalities were found in 2 control groups consisting of 9 parkinsonism cases without central nervous system Lewy bodies, and 17 cases without parkinsonism. The filamentous Lewy body (type A) was found in the perikaryon and was surrounded by neuromelanin, whereas the other forms (type B and C) were seen in nerve cell processes. Mitochondrial inclusions, present mainly, but not exclusively, in neuromelanin-containing cells, were not related to Lewy body formation or to parkinsonism.
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 13-25 
    ISSN: 1432-0533
    Schlagwort(e): Chordoma ; Tissue and organ culture ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Explants of a human sacral chordoma were successfully maintained on collagen-coated coverslips, gelfoam sponge matrices, and Millipore filter platforms for up to 30 days. Tumor cells cultured on collagen-coated coverslips became increasingly vacuolated whereas those maintained in organ culture were entirely free of vacuoles after 22 days in vitro. A single basic tumor cell, small and polygonal with a large central spherical nucleus and abundant endoplasmic reticulum and Golgi apparatus, was recognized. Vacuoles were formed as the result of the progressive expansion of smooth endoplasmic reticulum. Coalescence of these vacuoles produced the physaliferous cell of light microscopy.
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 139-150 
    ISSN: 1432-0533
    Schlagwort(e): Electron microscopy ; Olfactory esthesioneurocytoma ; Neurosecretory granules ; Microtubules ; Dystrophic axons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary One case of malignant tumour of the left nasal cavity is reported in a woman 56 year old, affected by the disease 24 years. Numerous recurrences appeared and various histological diagnoses were performed. At the last surgery, the tumour invaded the ethmoïd and was a typical olfactory esthesio-neurocytoma. By electron microscopy, mature ganglion cells with dense cored vesicles (neurosecretory granules) were densely packed. Neuritic processes with microtubules were rarely normal in size and their content was most often abnormal; furthermore dystrophic axons were noted in great number.
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  • 27
    ISSN: 1432-0533
    Schlagwort(e): Neurinoma ; ENU ; Prenatal carcinogenesis ; Transplantability ; Metastases ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary With a single dose of 80 mg/kg ENU, a tumour originating from the trigeminal nerve was induced transplacentally in the offspring of a Sprague-Dawley rat. The neoplasm diagnosed as a neurinoma, was transplanted over 20 passages to 5 six-month-old Sprague-Dawley rats in each case. During this time, the biological behaviour of the tumour as well as its histological appearance were followed. Ultrastructural observations were made of the 20th passage. The tumour caused multiple metastases in the lung and in the lymph nodes of the neck in 30 animals. Recurrences were formed within a week, metastases of the lung appeared from then on in all cases. During the time of transplantation, the neurinoma dedifferentiated histologically so markedly that it was no longer possible to classify the neoplasm as a neurogenous tumour after 20 passages. Ultrastructurally, poorly differentiated Schwann cells could nervetheless be recognized.
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 295-305 
    ISSN: 1432-0533
    Schlagwort(e): PKU bodies ; Demyelination ; Dysmyelination ; Neuroglia ; Inborn errors of metabolism ; Phenylketonuria ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructure of various inclusions within oligodendroglial cells in the brains from two phenylketonuric patients was studied. Characteristic lamellar, oval, slightly irregular inclusions measured between 0.5 and 2 micra in diameter and were bounded by a single membrane. The longitudinal and transverse lamellae of these inclusions had a distinct pattern. In analogy to lamellated but different inclusions of other diseases, these structures were termed “PKU bodies”. Various possibilities that would explain the morphogenesis of the PKU bodies and other inclusions in the oligodendroglial cells, and the significance of these findings, are discussed.
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 34 (1976), S. 321-327 
    ISSN: 1432-0533
    Schlagwort(e): Muscle fibres ; Amyotrophic lateral sclerosis ; Werdnig-Hoffmann disease ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Muscle biopsies from 5 cases of Werdnig-Hoffmann disease and 4 cases of ALS were investigated by histology and electronmicroscopy. The differences in morphology found in the atrophic muscle fibres in ALS and in W.H. diesease consisted mainly in the shape and structure of their cells and the number of the nuclei. Atrophic muscle fibres irregular in shape and size with degenerative changes and accumulated nuclei observed in ALS were markedly different from the picture of the fibres in W.H. disease. The presence of small muscle cells uniform diameter with well preserved architecture and single nuclei and numerous myotube-like cells seem to indicate a foetal defect in children with W.H. disease.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 47-54 
    ISSN: 1432-0533
    Schlagwort(e): Entrapment neuropathy ; Fusiform nerve enlargement ; Segmental demyelination ; Axonal changes ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This paper reports on the study of a symptomless fusiform enlargement of the superficial peroneal nerve. The swelling was located in the part of the nerve passing through the aponevrosis. On incision of the epineurium small swellings were seen in the nerve fascicles. A fascicular biopsy was done and the fascicles studied by teasing and by optic and electron microscopy. Isolated nerve fiber study gave evidence of segmental demyelinisation with subsequent remyelinisation in almost all the myelinated fibers. These abnormalities were only encountered in the swollen part of the fascicle. A striking proliferation of cells was demonstrated in isolated fibers by counter-staining with hematoxylin. Electron microscopy showed primary demyelinsation and cellular proliferation affecting Schwann-cells (without onion bulb formations), fibroblasts and giant-vacuolated histiocytes. There was also a massive increase of endoneurial fluid. A few Büngner bands were seen. These rare abnormalities appear to be caused by chronic irritation of the nerve in its passage through the aponebrosis.
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 34 (1976), S. 207-218 
    ISSN: 1432-0533
    Schlagwort(e): Immunomyopathy ; Muscle disease ; Electron microscopy ; Experimental muscle pathology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An experimental model of the autoimmune process was developed to study the ultrastructural aspects of immunomyopathies. Every type of muscle fibre organelle was affected and the severity of injury increased in direct proportion to time following immunization. It is suggested that ultrastructural methods are useful in studies concerned with the analysis of structural aspects of experimental immunomyopathies.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 137-152 
    ISSN: 1432-0533
    Schlagwort(e): Trembler mouse ; Peripheral neuropathy ; Electron microscopy ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The Trembler mouse is a neurological mutant showing dominant inheritance. The peripheral nerves show a delay in myelination, segmental demyelination and the development of an onion bulb neuropathy. Using electron microscopy a comparative morphometric study of nerve fibres in the sciatic nerve in normal and Trembler mice was made. The animals ranged in age from 3 days to adult. The following features were noted: 1. Mean axon diameters of the Trembler mice were smaller than normal at all ages. 2. Myelination was delayed and myelin was thinner than normal in the Trembler mice. 3. The ratio of myelin thickness to axon diameter was reduced in Trembler mice. 4. There were no significant quantitative or qualitative differences observed between middle and distal levels of Trembler nerves. The balance of evidence from these findings and the previous morphological studies is in keeping with the suggestion that the primary lesion resides in the Schwann cell.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 369-379 
    ISSN: 1432-0533
    Schlagwort(e): Leukodystrophy, metachromatic ; Prenatal diagnosis ; Sulphatide accumulation ; Myelination, central, peripheral ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Light and electronmicroscopic findings are reported in a case of metachromatic leukodystrophy diagnosed prenatally who died after iatrogenic abortion during the 23th week of gestation. The brain of this foetus was not yet myelinated while the spinal cord showed early, and the peripheral nerves advanced myelination. The onset and the degree of myelination were similar as in a normal foetus of the same age. Ultrastructurally there was evidence of sulphatide storage before the beginning of myelination. During myelination lysosomal storage material, staining metachromatically in acid cresyl violet preparations, appeared in oligodendrocytes and Schwann cells. Besides sulphatide storage material, prominent amounts of neutral lipids were found in oligodendrocytes. Myelin breakdown was encountered very seldom.
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  • 34
    ISSN: 1432-0533
    Schlagwort(e): Experimental malignant Schwannomas ; Melanin and melanogenesis ; Tissue and organ culture ; Electron microscopy ; Pigmented nerve sheath tumors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Four melanin pigment-containing intracranial tumors were found in three Long-Evans rats in the course of experimental oncogenesis by transplacental ethylnitrosourea (ENU). One of them was a leptomeningeal melanoma. Aside from the presence of scattered melanin-pigmented cells, the other three had the typical histological features of ENU-induced malignant nerve sheath tumors. Two of the three tumors were studied by electron microscopy and in tissue and organ culture systems. One of them demonstrated progressive melanogenesis in vitro; the other failed to produce more melanin and showed increasing differentiation, with a Schwannoma-like pattern by light microscopy. Melanosomes and premelanosomes were identified in both tumors by electron microscopy; the other fine structural features were those of malignant Schwannomas. These observations are relevant to the controversy on the histogenesis of pigmented nerve sheath tumors occasionally encountered in man and on the relationship of these tumors to pigmented nevi. The findings in the present study support the view of Masson that neoplastic nerve sheath cells are capable of melanogenesis.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 35 (1976), S. 93-107 
    ISSN: 1432-0533
    Schlagwort(e): Substantia nigra ; Gunn rat ; Complex membranous bodies ; Bilirubin ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The substantia nigra of various aged hyperbilirubinemic (Gunn) rats was studied by means of electron microscopy. The cytological features observed in the neuronal somata were the presence of (1) complex membranous bodies (CMBs), (2) dilated cisternae of granular endoplasmic reticulum, (3) single membrane bound vacuoles and (4) enlarged mitochondria. Nearly every neuronal soma studied in two week old Gunn rats contained CMBs, which consisted of several layers of membrane that usually, but not always, surrounded small islands of cytoplasm. On occasion CMBs were seen to be directly connected with granular endoplasmic reticulum and, in a few instances, they were located within a cistern of endoplasmic reticulum. There were significantly fewer CMBs in the neuronal somata of adult Gunn rats. They were located peripherally in the somata or in the proximal portions of dendrites. Furthermore, in these animals the cytoplasm appeared normal and did not exhibit the features commonly seen in younger animals. Only a few hyperchromatic neurons were observed and no pronounced gliosis was evident. Therefore it is assumed that the majority of substantia nigra neurons recovered from the toxic effect of bilirubin or that the concentration of bilirubin deposited in the substantia nigra is not sufficient to be lethal. The hypothesis that is considered is that CMBs represent autophagic activity which results from exposure of neurons to bilirubin. The adjacent neurites and glia did not demonstrate the cytoplasmic changes that were characteristic of the neuronal somata.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 36 (1976), S. 31-38 
    ISSN: 1432-0533
    Schlagwort(e): Whipple's disease ; Central nervous system ; Granulomatous infiltration ; Electron microscopy ; Bacillary bodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Whipple's disease presenting as a neurological disease without gastrointestinal symptoms is an unusual occurrence. A 40 year old man suffered hypersomnia, memory loss and progressive ophthalmoplegia for 6 months prior to death. The nature of his disease was not established during life. Extensive granulomatous inflammation affecting the hypothalamus, hippocampus and periaqueductal gray matter of the brain was found to represent Whipple's disease by electron microscopy. Characteristic lesions were also present in spleen, mesenteric lymph nodes, small intestine and myocardium. Bacillary bodies and membranous inclusions similar to those seen in visceral lesions of Whipple's disease were present in macrophages. The findings supported the theory of direct involvement of the central nervous system by bacilli rather than a metabolic origin for the lesions.
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurology 211 (1976), S. 111-124 
    ISSN: 1432-1459
    Schlagwort(e): Peripheral nerve ; Peroneal muscular atrophy ; Nerve biopsy ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei 2 Patienten mit progressiver neuraler Muskelatrophie wurden Nervenbiopsien jeweils in einem frühen und in einem fortgeschrittenerem Stadium der Erkrankung entnommen und verglichen. In beiden Fällen zeigten bereits die frühen Biopsien ein völliges Fehlen der großkalibrigen, dickbemarkten Axone. Ebenfalls als frühe Veränderung wurde eine Erweiterung des endoneuralen Interstitiums festgestellt. Eine geringe Anzahl der vorhandenen bemarkten und unbemarkten Axone in allen Biopsien wies degenerative Veränderungen auf. Die für die progressive neurale Muskelatrophie typische Zwiebelschalenbildung der Schwannschen Zellen — möglicherweise eine Reaktion auf wiederholte De-und Remyelinisierungsvorgänge um dystrophische Axone — trat erst in den späteren Biopsien deutlicher hervor. Hinsichtlich der formalen Genese der hypertrophischen Neuropathie bei neuraler Muskelatrophie sind nach diesen Beobachtungen axonale Dystrophie und interstitielle Veränderungen des Endoneuriums als primäre Entmarkung und Zwiebelschalenbildung als sekundäre Phänomene zu betrachten. Die Möglichkeit einer kausalen Beziehung zwischen axonaler Dystrophie und interstitiellen Veränderungen wird an Hand der vorliegenden Befunde und Literatur diskutiert.
    Notizen: Summary Serial nerve biopsies were performed at an early, and at an advanced stage of the disease in 2 patients with progressive neural muscular atrophy. The early biopsy showed a complete loss of the large diameter and thickly myelinated fibres, as well as an expansion of the endoneurial interstitium in both cases. Myelinated and unmyelinated fibres exhibited axonal degeneration in all biopsies occasionally. “Onion bulb” formation, a typical feature of peripheral neuropathy in neural muscular atrophy, was found to be prominent only in the latter biopsies. As regards the formal pathogenesis of hypertrophic neuropathy in neural muscular atrophy, axonal dystrophy and interstitial changes of the endoneurium were regarded as primary phenomena, demyelination and “onion bulb” formation as secondary. A possible causal relation between axonal dystrophy and interstitial changes, observed in these cases, is discussed in the light of the present literature.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    European archives of oto-rhino-laryngology and head & neck 214 (1976), S. 27-48 
    ISSN: 1434-4726
    Schlagwort(e): Mononuclear Phagocytic System (MPS) ; Macrophages ; Rhinosinusitis ; Immunology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Neither the concept of the Reticulo-Endothelial-System (RES) Aschoff's (1924) nor that of the Reticulo-Histiocyte-System (RHS) provides a satisfactory framework into which the present knowledge of the phagocytic mononuclear cells can be fitted. Current knowledge concerning morphology, histochemistry (peroxydase and esterase activity), immunology (specific surface antigens, receptors on the cell membranes), function (immune phagocytosis, pinocytosis), kinetics (3H-thymidine labelling) and culture makes it possible to place all highly phagocytic mononuclear cells and their precursors in one system, which is called the Mononuclear-Phagocytic-System (MPS) (Langevoort, Conn, Hirsch, Humphrey, Spector, van Furth, 1969). Kinetic studies with labelled cells have shown, that mononuclear phagocytes originate from precursor cells in the bone marrow (stem cell → monoblasts → promonocytes), than are circulating in the peripheral blood as monocytes and are transformed to tissue macrophages entering tissues. The MPS comprises following cells in following organs: connective tissue (histiocytes resp. macrophages); liver (Kupffer-cells); lung (alveolar macrophages); lymph nodes (free and fixed macrophages); bone marrow (macrophages); serous cavities (pleural and peritoneal macrophages); bone tissue (osteoclasts?); nervous system (microglial cells) (see Table 1). The reticular cells, endothelial cells and fibroblasts (fibrocytes) can therefore not be included in the MPS. Besides differences in morphology, histochemistry and function, they derive from mesenchymal cells and not from the bone marrow as the MPS. The present investigation demonstrates the structure and significance of the MPS in various kinds of chronic-specific and non-specific rhinosinusitis. On semithin sections two kinds of macrophages can be distinguished light-microscopically: 1. Larger macrophages with many phagosomes (storage cells) (Fig. 1A), which can exhibit sometimes a ring-shape on sections embracing greater parts of the interstitium (Fig. 1B). Such forms are mainly found in chronic (maxillary) sinusitis and are interpretated as “scavenger” macrophages. 2. The second type consists of smaller macrophages with extremely ruffling of the cell surface, wich is interpretated as an expression of highly (specific?) stimulated states. These later macrophages can be seen mainly in edematous nasal polyps, which might be caused by allergic reactions of the anaphylactic type. The fine structure of the phagocytes is to some extend dependent on the actual development and functional state: there are “immature” macrophages, which are practically indistinguishable from blood monocytes (Fig. 2A); some of them can be stimulated and can therefore show many surface foldings and projections (Fig. 2B). The “mature” macrophage shows a well developped Golgi-area and many secondary lysosomes (Fig. 3). The storage type of the macrophages, which can predominate in some cases of chronic maxillary sinusitis, is characterized by many electron-lucent vacuoles (Fig. 4). The macrophages can transform unspecifically to epitheloid- and giant-cells, as it is shown in foreign bodys- and cholesterol-granulomas in maxillary sinusitis (Fig. 5A and 5B). This tranformation to epitheloid and giant-cells might also be induced specifically by stimulated T-lymphocytes in immunological reaction of the delayed type, for example in sarcoidosis (Fig. 6A) and tuberculosis (Fig. 6B) of the nose. The macrophage is not only of great importance as the carrier of the cellular immunity in the sense of Metschnikoff (1905), but he is also involved in the initiation and regulation of the specific humoral and cellular immune responses. These facts and the phagocytic and synthetic properties of the macrophages are discussed in regard to their significance for the etiology and course of chronic rhinosinusitis.
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Research in experimental medicine 168 (1976), S. 219-227 
    ISSN: 1433-8580
    Schlagwort(e): Initial phase of neurogenic pulmonary edema ; Perfusion fixation ; HRP ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The initial phase of pulmonary edema development following intracranial pressure elevation was studied by means of transmission electron microscopy. Using perfusion fixation and application of a blood tracer (HRP horseradish peroxidase) the time sequence and site of fluid leakage out of pulmonary vessels was demonstrated: - passage of edema fluid through intercellular clefts of alveolar capillary endothelium - edema accumulation in alveolar interstitial tissue - draining of edema fluid from the alveolar septum to the interstitium of terminal bronchioli and to lymphatic vessels. An early interepithelial fluid leakage out of the alveolar wall remains questionable.
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  • 40
    ISSN: 1432-1106
    Schlagwort(e): Rolando substance ; Degeneration ; Atrophy ; Axotomy ; Histochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Disappearence of fluorid-resistant acid phosphatase activity from the ipsilateral Rolando substance after transection of the peripheral nerve, is shown to be due to the cessation of enzyme supply from dorsal root ganglion cells to their central terminals. This is accompanied by (or ensues in consequence of) a fine structural derangement of these terminals (“degenerative atrophy”). Fine structural alterations of axon terminals undergoing degenerative atrophy, though similar to some extent to those seen during early phases of a Wallerian degeneration, are markedly different. Also myelinated nerve fibers, both in the dorsal horn and in dorsal columns, are affected by degenerative atrophy. This important, new trophical feature of sensory ganglion cells suggests a delicate metabolic balance between peripheral and central axonal branches of bipolar (pseudounipolar) cells. Degenerative atrophy raises serious implications in evaluating hodological experiments based upon Wallerian degeneration and offers new perspectives for theoretical and clinical neurology.
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  • 41
    ISSN: 1573-0832
    Schlagwort(e): Trichophyton mentagrophytes ; Thiocyanatopyrazole derivatives ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Four thiocyanatopyrazole derivatives were synthesized and their fungistatic activity was demonstrated in vitro against a number of dermatophytic fungi. In Trichophyton mentagrophytes, the most active compound induced an unusual increase of the plasma membrane with production of intra and extracytoplasmic complexes, a deterioration of nuclear and mitochondrial membranes and a formation of autophagic-like vacuoles. Plasmolysis, accompanied by an almost complete disorganization of cytoplasmic structures, seemed to be the final event. A possible mechanism of action of the compounds was discussed.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 169 (1976), S. 123-128 
    ISSN: 1432-0878
    Schlagwort(e): Venous endothelium ; Adrenaline infusion ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure of the endothelium lining the femoral and mesenteric veins in the rabbit was examined following the infusion of concentrations of adrenaline varying from 0.5 to 5.0 μg/kg. Control animals were infused with saline. Vesiculation of the endothelial cells was observed following each infusion of adrenaline, the effect being most marked with the highest dose used. It is suggested that this vesiculation may be associated with the release of antihaemophilic globulin and/or plasminogen activator from the endothelial cells.
    Materialart: Digitale Medien
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 179-195 
    ISSN: 1432-0878
    Schlagwort(e): Islets of Langerhans ; Horse pancreas ; Cell types ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Das Inselorgan der Bauchspeicheldrüse des Pferdes wurde an immersions- und perfusionsfixiertem Material untersucht. Dabei ließen sich nach der Immersions- wie Perfusionsfixation fünf Zelltypen unterscheiden: 1. A-Zellen, die im Zentrum der Insel liegen, 2. B-zellen, die hauptsächlich blasse Granula enthalten und den größten Teil der Inselperipherie ausmachen, 3. D-Zellen, die ebenfalls vorwiegend in der Inselperipherie liegen, 4. G-Zellen, die am Rand der Inseln und im exokrinen Pankreas anzutreffen sind, 5. S-Zellen (“small granule cells”), die relativ selten und nur in den Inseln zu finden sind. Über die Funktion und altersabhängigen Veränderungen dieser Zellen wird diskutiert. Die Bildung von hellen und dunklen Zellen halten wir für ein Artefakt, ebenso die Bildung von sog. Mischzellen, da diese Zelltypen nur nach Immersionsfixation auftreten.
    Notizen: Summary The islets of Langerhans of the equine pancreas were examined with the electron microscope after immersion or perfusion fixation. Five cell types could be distinguished after fixation by either technique: 1. A-cells, situated at the center of the islets, 2. B-cells, containing mostly “pale granules” and constituting the principal cell type of the periphery of the islets, 3. D-cells, also located mainly at the periphery of the islets, 4. G-cells, found at the edge of the islets and in the exocrine pancreas, and 5. S-cells, (small granule cells), which are relatively few in number and occur only in the islets. The function and age-dependent modifications of these cells are discussed. The formation of light and dark cells and of “mixed cells” are regarded as artifact, since cells of this type occur only under the condition of immersion fixation.
    Materialart: Digitale Medien
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 167 (1976), S. 265-288 
    ISSN: 1432-0878
    Schlagwort(e): Myelinated fibres ; Visual cortex ; Stereology ; Development ; Electron microscopy ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary With the aid of stereological procedures the development of myelinated nerve fibres (MF) was quantitatively investigated in electron micrographs of the visual cortex from animals of different ages: 36 days-old, the age at which fibres first appear, through adulthood. A short description of tissue treatment, methods and qualitative results is given. The following quantitative results are presented: 1. Myelinization begins at about the 36th day postpartum and is not completed by the 164th day. At this time a lack of about 20% MF can be observed. 2. The average diameter of MF decreases from 1.3 μm to 0.8 μm from day 36 to adulthood. 3. The first MF appear near the border of the album. 4. Beginning with the 55th day, small MF arise in layer I, showing two periods of growth. 5. The maximum MF density in the region of layer IV corresponds to the strip of Baillarger. Other aspects of visual cortex development are dealt with in the Discussion. The following conclusions can be drawn: a) The growing of inand output-MF is completed first. b) The development of the internal connecting systems in layers I and IV begins a little later and is completed by the 5th month. c) The MF in layers II and III appear after the 4th month. Kaes (1907) has also described a continuation of MF growth in man lasting into the twenties.
    Materialart: Digitale Medien
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 169 (1976), S. 395-403 
    ISSN: 1432-0878
    Schlagwort(e): Taste buds ; Fishes ; Electron microscopy ; Nucleolus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Taste buds occur in the epithelium of the catfish barbel along its entire length. Two major cell types, light and dark cells, occupy the upper two-thirds of the taste bud. A third cell type, the basal cell, lies on the basal lamina and is essentially separated from the light and dark cells by a plexus of unmyelinated nerve fibers. The dark cells have branching processes, both apically and basally whereas the light cells have a single apical process and many basal processes. The apical processes of dark cells contain secretory granules, while the apical processes of light cells contain an abundant agranular endoplasmic reticulum. Light cell nuclei contain bundles of 10 nm filaments, often arranged in the shape of a cup or ring, but nucleoli are rarely seen. It is suggested that this morphology indicates a low degree of RNA synthesis by light cells. The basal cells contain large numbers of vesicles, about 60 nm in diameter, which are sometimes seen in clumps in relation to an adjacent nerve fiber in a configuration resembling a synapse. Curiously, although basal cells present a large surface to the basal lamina, there are no hemidesmosomes. This suggests that the basal cell does not originate from the epidermis.
    Materialart: Digitale Medien
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 172 (1976), S. 157-169 
    ISSN: 1432-0878
    Schlagwort(e): Placenta (Human) ; Capillaries ; Tight junctions ; Electron microscopy ; Freeze-fracturing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of human placental capillaries was investigated using perfusion fixation and the freeze-fracturing technique. The capillaries have a continuous endothelium especially rich in microfilaments, whereas micropinocytotic vesicles are exceedingly scarce. The endothelial cells are connected by three types of junctions: (1) zonulae occludentes characterized by 2 to 4 focal regions of membrane contact in thin-sectioned specimens and an equal number of ridges on the membrane E-face in freeze-fractured specimens; (2) small gap junctions associated with the zonula occludens. (3) attachment plaques resembling zonulae adhaerentes in their fine structure. Endothelial cells are provided with long, circularly oriented pseudopodial extensions, which may be responsible for intermittent constrictions of the vessel lumen. These findings indicate that diaplacental transport at the level of the fetal capillary is controlled by the cytoplasm of the endothelial cells and probably occurs only to a very limited extent by way of micropinocytotic vesicles.
    Materialart: Digitale Medien
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 174 (1976), S. 281-288 
    ISSN: 1432-0878
    Schlagwort(e): Striated muscle ; Guinea-pig urethra ; Innervation ; Morphology ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Light and electron microscopic techniques have been used to determine the distribution, morphology and innervation of subepithelial striated muscle cells in the wall of the proximal urethra of the male guinea-pig. These cells form a continuous layer, immediately beneath the urethral epithelium extending from the bladder neck to the termination of the ejaculatory ducts into the proximal urethra. They differ from “typical” striated muscle fibres (as seen in the external urethral sphincter) by their small size, rich acetylcholinesterase content and the irregular arrangement of intracellular myofilaments and sarcoplasmic reticulum. In addition, motor end plate regions have not been observed on these striated cells when examined using a light microscopic histochemical technique. The cells are related to acetylcholinesterase positive nerves which run between them in a manner compatible with the occurrence of “en passant” synaptic interactions. Using electron microscopy, axonal varicosities containing small (50 nm diameter) agranular vesicles are encountered 50 nm from the striated cells; membrane specialisations characteristic of motor end plates have not been observed on the cells. The findings are discussed, particularly in relation to the distribution, unusual morphology and innervation of these subepithelial muscle cells.
    Materialart: Digitale Medien
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 168 (1976), S. 65-78 
    ISSN: 1432-0878
    Schlagwort(e): Muscle fibre types ; Axolotl (Ambystoma mexkanum) ; Morphometry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Morphometric analysis by light microscopy of p-phenylene-diamine stained semithin sections of axolotl tail muscle revealed differences in the cross-sectional area of the fibres and in the number of mitochondria and of lipid inclusions per fibre, and indicated the presence of three distinct types of fibres. The tripartition was found to be statistically highly significant. Representative fibres from each group established by light microscopic morphometry were subjected to an ultrastructural morphometric analysis. The volume content of mitochondria amounted to 9.8% of the fibre volume for red, 4.0% for intermediate and 0.8% for white fibres. The myofibrils composed 60%, 70% and 83% in the same fibres. The volume of the sarcotubular system (t-tubuli and sarcoplasmic reticulum) was 2.5% in red, 4.5% in intermediate and 11.7% in white fibres. The three fibre types also demonstrated differences in myofibrillar cross-striation pattern and number of triads. The reliability of the light microscopic morphometry was tested by correlation with EM montages of the representative fibres.
    Materialart: Digitale Medien
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 174 (1976), S. 427-430 
    ISSN: 1432-0878
    Schlagwort(e): Chromatoid body ; Acrosome ; Electron microscopy ; Myxine glutinosa L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Eine vorübergehende enge Beziehung zwischen dem Chromatoiden Körper und dem sich entwickelnden Acrosom wird in jungen Spermatiden von Myxine glutinosa demonstriert.
    Notizen: Summary A transient close relationship between the chromatoid body and the developing acrosome is demonstrated in early spermatids of Myxine glutinosa.
    Materialart: Digitale Medien
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 175 (1976), S. 59-72 
    ISSN: 1432-0878
    Schlagwort(e): Retina ; Xenopus ; Rods ; Cones ; Hemicholinium-3 ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Hemicholinium-3 (HC-3), a drug which prevents synthesis of acetylcholine in neurons, when injected intraperitoneally in doses as low as 2×5 mg/kg produces marked ultrastructural changes and damage in rod but not in cone photoreceptors. In rods it causes a reduction in cytoplasmic back-ground density, swelling of the endoplasmic reticulum, ballooning of the outer membrane of the nucleus, leaching of the nucleoplasm and clumping of the nuclear chromatin. In dark-adapted rods HC-3 produces some loss of cytoplasmic synaptic vesicles but no reduction in numbers of those vesicles which lie adjacent to the synaptic ribbons. In light-adapted rods the drug does not cause such an apparent reduction of synaptic vesicles but does induce a considerable reduction in numbers of vesicles associated with the ribbons. These structural changes are discussed in the light of what is known about the pharmacology of HC-3 and neurotransmitter release from vertebrate photoreceptors.
    Materialart: Digitale Medien
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 175 (1976), S. 369-390 
    ISSN: 1432-0878
    Schlagwort(e): Electron microscopy ; Crustacea ; Synaptic vesicles ; Biogenic amines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The appearance and distribution of dense-core vesicles in the stomatogastric ganglion of the spiny lobster, Panulirus interruptus, were examined using transmission electron microscopy. Following five fixation techniques, three types of dense-core vesicles were identified on the basis of size and morphology. Type-I vesicles are found in a distinct neuronal fiber system that appears to be involved in chemical transmission within the ganglion. Type-II vesicles occur in nerve processes in the ganglion, in major nerve trunks and in the perineural sheath of the nerves and ganglion. Type-III vesicles are present in all neuronal somata of the ganglion. The distinct morphology and location of the three types of vesicles suggest that their functional roles differ. Furthermore, the histochemical, biochemical and physiological data available for the Stomatogastric ganglion indicate that Type-I vesicles may store dopamine.
    Materialart: Digitale Medien
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  • 52
    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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  • 53
    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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  • 54
    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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  • 55
    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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  • 56
    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
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  • 57
    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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  • 58
    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
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  • 59
    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
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  • 60
    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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  • 61
    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
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  • 62
    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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  • 63
    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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  • 64
    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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  • 65
    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
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  • 66
    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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  • 67
    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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  • 68
    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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  • 69
    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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  • 70
    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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  • 71
    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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  • 72
    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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  • 73
    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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  • 74
    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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  • 75
    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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  • 76
    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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  • 77
    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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  • 78
    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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  • 79
    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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  • 80
    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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  • 81
    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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  • 82
    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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  • 83
    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
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 84
    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
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 85
    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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  • 86
    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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  • 87
    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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  • 88
    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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  • 89
    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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  • 90
    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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  • 91
    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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  • 92
    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
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 93
    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
    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) 
    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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  • 95
    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
    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. 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
    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. 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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  • 98
    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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  • 99
    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
    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. 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
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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