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  • Articles: DFG German National Licenses  (264)
  • 1970-1974  (264)
  • 1965-1969
  • 1955-1959
  • 1920-1924
  • 1973  (141)
  • 1972  (123)
  • Biochemistry and Biotechnology  (195)
  • Electron Microscopy
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  • Articles: DFG German National Licenses  (264)
Material
Years
  • 1970-1974  (264)
  • 1965-1969
  • 1955-1959
  • 1920-1924
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 23 (1973), S. 133-140 
    ISSN: 1432-0533
    Keywords: Metachromatic Leukodystrophy ; Neuronal Inclusions ; Laminated Bodies ; Mucopolysaecharides ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural findings of the metachromatic granules in the anterior horn cells of the spinal cord in a case of metachromatic leukodystrophy are presented. The typical neuronal inclusions are concentrically laminated bodies of approximately 1 μ. In addition various morphological variations of the abnormal inclusions are seen side by side in the same neuron and give the impression that the highly organized laminated bodies are formed as a result of progressive deposition of membranous material upon a nidas which is initially amorphous, which then becomes granular, fibrillar or horizontally striped and finally multilaminated. Material capable of binding colloidal iron particles is demonstrated in these inclusions, and suggests the presence of mucopolysaccharides.
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  • 2
    ISSN: 1432-0533
    Keywords: Electron Microscopy ; Encephalomyocarditis (EMC) Virus ; Neurotrophic Viruses ; Viremia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary One hundred and eighty 12 week old Swiss mice were injected subcutaneously with 0.1 ml suspensions of the E and M variants of encephalomyocarditis (EMC) virus. Ninety-seven surviving mice were sacrificed at intervals from 24 h to 21 days following injection. The M variant group showed only mild microglial proliferation in the brain, while the E variant group displayed various alterations in the astrocytes and neurons exhibiting loss of nuclear membranes and marked changes in the mitochondria and other organelles. In addition, the neuronal cytoplasm displayed aggregates of fine electron-dense granules on the third day which increased in size during the fifth to seventh day. After 7 days, the neurons contained occasional rhomboid structures composed of rows of parallel arranged granules which were similar to those observed in the viscera after EMC virus infection.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 24 (1973), S. 62-67 
    ISSN: 1432-0533
    Keywords: Dystrophia Myotonica ; Electron Microscopy ; „Fingerprint Inclusions” in Muscle Fibres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary „Fingerprint inclusions” were observed in numerous muscle fibres of 3 cases of dystrophia myotonica studied by electron microscopy in two different laboratories. They consist of parallel or concentric palisades of short electron dense linear elements. Identical „fingerprint inclusions” were reported in two other clinical conditions and cannot therefore be regarded as specific for a particular muscle disease. Their origin and significance remain obscure.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 26 (1973), S. 45-57 
    ISSN: 1432-0533
    Keywords: Electron Microscopy ; Extracellular Fibrils ; Neurologia ; Retina ; New Formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Extracellular formation of microfibrils was observed in the cavities of peripheral cystoid degeneration in senile human eyes. The ultrastructure of the fibrils is described and the source of production of the fibrillar material is discussed. It originates most probably from neurological cells, within or surrounding the cysts.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 25 (1973), S. 1-13 
    ISSN: 1432-0533
    Keywords: Electron Microscopy ; Myxopapillary Ependymoma ; Basement Membrane ; Filum Terminale ; Collagen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A fine structural study of a myxopapillary ependymoma of the filum terminale confirms and emphasizes the distinctive morphological features of this tumor. Electron basement membrane production were identified. It is suggested that they are related to the growth of ependymal tumor cells in juxtaposition to the collagen normally present in the conus medullaris and filum terminale.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 25 (1973), S. 207-219 
    ISSN: 1432-0533
    Keywords: Aujeszky's Disease ; Inoculation ; Virus Particles ; Electron Microscopy ; Neuronal Degeneration ; Demyelination ; Axoplasmic Transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sixteen calves were killed at intervals during the course of the disease from 48 h onwards after subcutaneous infection with Aujeszky's disease virus. Ultrastructural changes were evident in the spinal ganglia from 84 h post-inoculation and the intercostal nerves from 96 h post-inoculation. The cytopathic changes in the spinal ganglia consisted of neuronal degeneration, neuronophagia, Schwann cell degeneration and cellular infiltration. The neuronophagic nodule was invariably contained within an intact sheath of satellite cells. Changes in the intercostal nerves were less dramatic but cellular infiltration was frequently seen and occasional Schwann cells were degenerate. In the terminal stages of the disease demyelination was rarely observed. In the ganglion virus was invariably seen in degenerating neurons and occasionally in Schwann cells and monocytes. Satellite cells were rarely infected even when ensheathing an infected neuron. Extra-cellular virus was not observed in ganglia or nerves. Schwann cells and monocytes in the nerves were occasionally infected. Virus particles were seen in the axoplasm both in the ganglion and in the entire length of the nerve. The particles in the axoplasm varied in morphology; thus unenveloped and enveloped particles, and particles in the process of acquiring an envelope were recognised. It was concluded that the neural pathway of Aujeszky's disease virus is probablyvia the axoplasm.
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  • 7
    ISSN: 1432-0533
    Keywords: Tissue Culture ; Electron Microscopy ; Enzyme Histochemistry ; Sympathetic Ganglioneuroblastoma ; Medulloblastoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The results of combined tissue culture, ultrastructural and enzyme histochemical investigations carried out on a sympathetic ganglioneuroblastoma are reported.In vitro a vigorous sprouting of newly formed neuritic processes was observed a few days after explantation. The enzymatic reactions for acethylcholinesterase were positivein situ as well asin vitro. The tumor elements showed the ultrastructural characteristics of nerve cells with many microtubuli and filaments, plenty of ribosomes, well developed endoplasmic reticulum. Dense bodies, corresponding to neurosecretion granula (catecholamines) were also observed. Synaptic structures were missing. The results of these investigations confirm that this kind of tumor is different from so-called medulloblastoma.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 23 (1973), S. 23-31 
    ISSN: 1432-0533
    Keywords: Chronic Polymyositis ; Virus-Like Particles ; Electron Microscopy ; Paramyxovirus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electron microscopic examination of a biopsy of skeletal muscle from a young girl with chronic polymyositis revealed the presence of sarcoplasmic and perinuclear inclusions. A large number of virus-like particles was demonstrated at the surface of muscle cells and in extracellular space. On the basis of the microscopic appearance it is suggested that the virus particles belong to one of the members of the paramyxovirus group.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 24 (1973), S. 273-286 
    ISSN: 1432-0533
    Keywords: Muscle ; Acromegaly ; Histochemistry ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Muscle biopsies from 9 acromegalics were examined by conventional histological and histochemical techniques. Six biopsies were also examined with the electron microscope. Isolated fibre necrosis or vacuolar degeneration was found in 3 biopsies and increased numbers of internal nuclei in 5 biopsies. A high glycogen content was demonstrated in many fibres in each biopsy by the PAS method and by electron microscopy. Routine enzyme histochemical techniques showed hypertrophy of type I and type II fibres in 2 subjects, hypertrophy of type I fibres only in 2 subjects, atrophy of both fibre types in 2 subjects and atrophy of type II fibres only in 4 subjects. Electron microscopy showed large amounts of lipfuscin pigment in many fibres while some fibres had large sarcolemmal nuclei with prominent nucleoli, and a prominent Golgi apparatus. Satellite cells were found in 3 biopsies. In one biopsy coiled membranous configurations thought to consist of phospholipids, and tubular aggregates thought to be derived from degenerating mitochondria were present at the periphery of a number of type II fibres. It is postulated that some of the ultrastructural changes found in muscle fibres are the result of the growth hormone-induced hypertrophic process and the increased turnover of cytoplasmic components associated with it while others reflect the atrophic process in some muscle fibres.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 24 (1973), S. 345-349 
    ISSN: 1432-0533
    Keywords: Cockayne's Syndrome ; Peripheral Nerve ; Electron Microscopy ; Demyelination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of sural nerve biopsies was studied in two sisters with Cockayne's syndrome. Both had severe physical and mental retardation and evidence of peripheral neuropathy. Striking alterations in the myelin sheath with relative preservation of the axis cylinder were noted in both. There were also electron dense bodies in the Schwann cells. These findings support the suggestion that Cockayne's syndrome may be a form of leukodystrophy.
    Type of Medium: Electronic Resource
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 26 (1973), S. 259-264 
    ISSN: 1432-0533
    Keywords: 6-Aminonicotinamide ; Tissue Culture of Chick Spinal Cord ; Electron Microscopy ; Neurotoxic Effects ; Glucose-6-Phosphate Dehydrogenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Well myelinated cultures of chick embryo spinal cord were exposed to medium containing 6-aminonicotinamide in a concentration of 0.5 mmol for up to 48 h. By 24–48 h of exposure to the antivitamin, neurons showed a granulovacuolar degeneration which later led to the formation of large vacuoles in the neuronal perikarya. Myelin degeneration was also observed in this period in the form of swelling, beading and ballooning. Electron microscopy revealed moderately swollen mitochondria and dilated endoplasmic reticulum as the earliest neuronal change. Later, neurons became pyknotic and the cytoplasmic organelles disintegrated. Presynaptic endings and glial cells, however, was spared any degenerative change. Intermittent and irregular splitting of myelin lamellae were also observed along the intraperiod lines. Biochemical assay of the glucose-6-phosphate dehydrogenase activity in the experimental cultures showed that 45% of the enzyme activity was lost during the 30-h period. It is concluded that the formation of 6-aminonicotinamide analogues of NAD and NADP coenzymes leads to the impairment of the pentose phosphate pathway and the glucose turnover, and thus produces neurotoxic effects in the central nervous system.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 26 (1973), S. 275-284 
    ISSN: 1432-0533
    Keywords: Minimata Disease ; CNS Degenerative Disorder ; Mercury Poisoning ; Focal Demyelination ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of suspected mercury poisoning (Minamata disease) was studied. Microscopic and ultrastructural changes in the nervous system were compared with those of a confirmed case of mercury poisoning from Minamata Bay, Japan, and those from exprimental animals intoxicated with methyl mercury. Disintegration of the granular layer, disappearance of the Purkinje cells with Bergmann's fiber proliferation and demyelination of the fiber tracts were observed in the cerebellum. Ultrastructural examination also revelad extensive proliferation of astrocytic fibers and characteristic focal demyelination and loosening of the myelin sheaths in many nerve fibers. Such pathological changes were consistent with those observed in both human cases and experimental animals poisoned by methyl mercury.
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  • 13
    ISSN: 1432-0533
    Keywords: Cerebral Ischaemia ; Recirculation ; Enzyme Histochemistry ; Electron Microscopy ; Dendrite Swelling ; Pinocytosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Complete cerebral ischaemia of 30 and 90 min was produced in normothermic barbiturized cats by clamping the innominate and subclavian arteries and lowering the systemic blood pressure. When the brains were adequatly recirculated after 30 min of ischaemia, electron microscopical and histochemical changes observed at the end of the circulatory arrest, were almost fully reversible. Endothelial cells of capillaries showed increased number and size of pinocytotic vesicles and numerous intraluminal flaps. ATPase activity was increased in the capillary walls and glial cells. Opposite to this, severe and irreversible ultrastructural changes were observed after 90 min of ischaemia, and all the enzyme activities studied were sharply decreased.
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  • 14
    ISSN: 1432-0533
    Keywords: Experimental Neurinoma ; Schwannoma ; Nitrosourea ; Tumor Trausplantation ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Nervous system tumors were induced in the offspring of BD-IX (inbred) and CFE (non-inbred) rats by transplacental administration of ethylnitrosourea. Tumors of the peripheral nervous system (PNS) were obtained in approximately 80% of all animals, and tumors of the central nervous system (CNS) in 16%. Although several peripheral nerves were sites of tumor formation, the trigeminal nerve was the most frequent nerve affected. In male CFE rats, 70% of all PNS tumors affected the trigeminal nerve. The incidence of trigeminal nerve tumors in female BD-IX rats was only 33% of PNS tumors. Light and electron microscopy showed that the PNS tumors are made-up of Schwann cells, and behave like malignant tumors. The tumors began as a proliferation of recognizable Schwann cells, later they lost their basement lamina, destroyed the nerve tissue and invaded neighboring structures, but did not metastasize. Like their human counterparts, they showed “dense” and “loose” areas. In both of these, Schwann cells were recognized as the tumor cells. Trigeminal nerve tumors were transplanted fromin vitro cultured cells or directly from transplanted fresh tumor fragments to isologous rats (BD-IX). Subcutaneous. intraperitoneal and intracerebral transplants were done. The morphology and behavior of the transplanted tumors were similar to the original malignant neurinomas.
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  • 15
    ISSN: 1432-0533
    Keywords: Chronic Progressive Ophthalmoplegia ; Cerebellar Ataxia ; Electron Microscopy ; Enzyme Histochemistry ; Mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electron microscopic and enzyme histochemical studies were performed on the cerebellum and the ocular and deltoid muscles from a 38 year old woman who developed bilateral ptosis at the age of nine years. Histologically the cerebellum appeared normal. The biopsies of three ocular muscles showed varying sizes of muscle fibers which were rounded and contained increased numbers of subsarcolemmal nuclei. The deltoid muscle stained by hematoxylin and eosin appeared normal, but the trichrome stain showed increased numbers of red granules within the sarcolemma corresponding ultrastructurally to increased numbers of abnormal mitochondria. These abnormal mitochondria displayed increased reaction products with LDH, NADH and SDH preparations, while the muscle gave normal reaction in phosphorylase, PAS and myosin ATP preparations. Chemical studies on the cerebellum showed normal proteolipids, glycolipids and phospholipids. Ultrastructurally, the cerebellum, the myofibers of three ocular muscles and the deltoid muscle exhibited abnormal mitochondria which showed peculiarly arranged circular cristae. They frequently contained paracrystalline structures which consisted of individual tubules arranged in a helical pattern. Frequently, the abnormal mitochondria were replaced by dense rectangular inclusions and occasionally showed complete transition to crystalline structures.
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  • 16
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    Electronic Resource
    Springer
    Acta neuropathologica 23 (1973), S. 9-22 
    ISSN: 1432-0533
    Keywords: Earliest Ischaemic Neuronal Change ; Astrocytic Swelling ; Mitochondrial Swelling ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A combined light and electron microscope study was made of the alterations occurring in the neurones and astrocytes of the neocortex and hippocampus of rats killed immediately after intermittent exposures to nitrogen of 5 and 15 min. Blood flow in the right common carotid artery had previously been interrupted by application of an artery clasp which was removed after the exposure to nitrogen and the animals killed by perfusion-fixation with glutaraldehyde. Microvacuolation (MV), the earliest stage of anoxic-ischaemic neuronal damage, was observed in the ipsilateral neocortex and hippocampus of both groups and ischaemic cell change (ICC) bilaterally in the neocortex of animals exposed for 15 min. Ultrastructural examination showed the microvacuoles to be swollen mitochondria. Slightly dense, mildly distorted, non-vacuolated neurones were also seen in the neocortex and hippocampus. They did not exhibit the ultrastructural changes seen in MV and ICC. Swollen astrocytic processes were sometimes seen around the damaged neurones, more frequently after 15 min exposure. Slight swelling of perivascular astrocytic processes was occasionally observed while the extracullular spaces in the neuropil remained unaltered. This implies that the accumulation of fluid in oedematous grey matter is confined to the astrocytic compartment. The reversibility or otherwise of all the neuronal alterations is discussed.
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  • 17
    Electronic Resource
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    Springer
    Acta neuropathologica 25 (1973), S. 149-160 
    ISSN: 1432-0533
    Keywords: Nutritional Encephalopathy ; Brain Edema ; Vitamin E Deficiency ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Focal lesions were induced in the cerebellum by feeding chickens a diet high in unsaturated fats and deficient in vitamin E. Ultrastructurally, the lesions consisted of central and peripheral zones. The central zone was characterized in the cortex and white matter by enlargement of the intercellular space, swelling of astrocytes, vacuolization of oligodendrocytes, ballooning of nerve fibers, degenerative changes in small blood vessels, and extravasation of plasma and blood cells. The peripheral zone was characterized by enlargement of the intercellular space in the white matter, swelling of astrocytes in the cortex, and the accumulation of dark bodies in the endothelium of small blood vessels. The results suggest that this nutritional encephalopathy is caused by alterations in the permeability of the vascular bed due to the dietary stress of unsaturated fatty acids in the absence of vitamin E.
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 23 (1973), S. 326-333 
    ISSN: 1432-0533
    Keywords: Hexachlorophene Intoxication ; Cerebral Edema ; Status Spongiosus ; Electron Microscopy ; Myelinopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Hexachlorophene intoxication produced cerebral edema in rats and mice characterized by the accumulation of fluid within myelin sheaths. Vessels remained impermeable to Trypan Blue. The amount of water in the brains of affected mice gradually returned to normal when the animals were put back on a normal diet. Correspondingly the status spongiosus decreased in severity in recovering animals. Some axonal degeneration occurred but there was no evidence of any breakdown of myelin lipids. The similarity of this encephalopathy to that seen following intoxication with triethyltin, isonicotinic acid hydrazide and cuprizone is emphasized. The potential toxicity of hexachlorophene to human infants is discussed.
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  • 19
    ISSN: 1432-0533
    Keywords: Subarachnoid Hemorrhage ; Glycerol ; Phenoxybenzamine ; Cerebral Edema ; Prevention ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Twenty-four hours and one week, respectively, after subarachnoid hemorrhage (SAH) had been experimentally induced in baboons, therapeutic dosages of glycerol and/or phenoxybenzamine hydrochloride were injected intravenously. Groups of three animals were studied at various time intervals after SAH: one animal served as a control, one animal per group received phenoxybenzamine hydrochloride (PBZ), and thefinal animal received both PBZ and a 10% glycerol (in saline) injection. The animals were prepared for electron microscopy by whole body perfusion with a glutaraldehyde/phosphate fixative. Few ultrastructural abnormalities were noted in cerebral tissue in each of the animals receiving glycerol, whereas the brain tissue from the untreated animals and those which had been treated with PBZ alone showed morphological changes compatible with cerebral edema.
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  • 20
    ISSN: 1432-0533
    Keywords: Wilson's Hepato-lenticular Degeneration ; Primary Degeneration of Peripheral Nerve ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The sural nerve from a patient with'Wilson's hepato-lenticular degeneration was examined by electron microscopy. The myelin sheaths showed remarkable changes and the axons secondary changes, while the unmyelinated nerve fibres were intact. These findings demonstrate that pathological changes of peripheral nerves occur in Wilson's disease. The changes are considered to be primary degeneration of the myelin sheaths.
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  • 21
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    Acta neuropathologica 24 (1973), S. 117-127 
    ISSN: 1432-0533
    Keywords: Pinealoma ; Two-Cell Type Pattern ; Electron Microscopy ; Germinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Four pinealomas of the two-cell type (atypical teratomas) were investigated by electron microscopy. They all showed the same unique histological ultrastructure. The lymphocyte-like cells did not differ ultrastructurally from lymphocytes. Many plasma cells with well-developed rough surfaced endoplasmic reticulum were also seen. The small cells and the plasma cells were considered to be derived from blood cells. A variety of the large cells in the process of differentiation were observed. They had a large and ovoid nucleus with uniform granular chromatin and contained one or more prominent nucleoli. The large cells had many dilated cytoplasmic cisternae, numerous glycogen granules of about 250–300 Å in diameter and annulate lamellae. Ultrastructurally, the pinealoma of the two-cell type resembled the seminoma of testis which is of germ cell origin. This suggests that the pinealoma may be of germ cell origin.
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  • 22
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    Springer
    Acta neuropathologica 24 (1973), S. 128-152 
    ISSN: 1432-0533
    Keywords: Transneuronal Degeneration ; Olfactory Bulb ; Rabbit ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After peripheral deafferentation of the olfactory bulb of the rabbit obtained either spontaneously by atrophic rhinitis (main bulb only) or surgically, a transneuronal degeneration is observed by light microscopy: narrowing of the outer plexiform layer (30 to 40%), decrease (40%) in mean area of the mitral cells, light texture of the periglomerular neuropil. The study by electron microscopy at survival-times of from 8 h to 6 months shows: 1. intraglomerular dendritic lesions; 2. rarefaction of thick dendrites in the outer plexiform layer; 3. reduction of Nissl bodies in mitral and tufted cells. 4. periglomerular lesions: their morphology and laminar aspect could evoke a vascular origin. The interpretation of these modifications and their relation to transneuronal atrophy are discussed. Dark mitral- or granule cells have been observed neither in the main nor in the accessory olfactory bulbs, even when complete denervation occured.
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  • 23
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    Acta neuropathologica 26 (1973), S. 247-251 
    ISSN: 1432-0533
    Keywords: Argyria ; Silver Deposition ; Choroid Plexus ; Silver Granules ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 72-year-old woman developed generalized argyria after prolonged intranasal application of a colloidal silver solution. The brain parenchyma, including several infarcts, was free of silver, but the choroid plexus showed silver deposited in the basal lamina, the stroma including calcified bodies, and occasionally within a mesenchymal cell of the choroid plexus stroma. The basal lamina beneath the choroidal epithelium was most affected. The silver granules appeared solid and free of any limiting membrane.
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  • 24
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    Acta neuropathologica 26 (1973), S. 317-327 
    ISSN: 1432-0533
    Keywords: Peripheral Neuropathy ; Tangier Disease ; Schwann Cells ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Nerve biopsy findings are recorded for two previously reported patients with Tangier disease (hereditary high density lipoprotein deficiency). Both cases showed unusual clinical manifestations in comparison with other reported cases. The neurological disorder, symptoms from which began in the third decade, gave rise to a lower motor neuron deficit of unique distribution, which was accompanied by progressive sensory impairment limited for many years to loss of pain and temperature sensibility, ultimately involving all sensory modalities. Both biopsy specimens displayed similar features, with a gross loss of unmyelinated and myelinated axons, an extensive accumulation of lipid within Schwann cells, and excessive endoneurial collagenization. The axonal loss appeared to represent a primary axonal degeneration, there being no evidence of a demyelinating process. It is suggested that the accumulation of cholesterol within Schwann cells may be the result of a failure of cholesterol removal mechanisms or of intracellular lipid transport.
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  • 25
    ISSN: 1432-0533
    Keywords: Neuronal Inclusions ; Cerebrum ; Cholesterol Inhibitor ; Rat ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intraperitoneal injections of a hypocholesterolemic drug, AY9944 produced neuronal cytoplasmic inclusions in the brain of Wistar strain of rats. The inclusions were numerous and larger in size in the younger age groups but gradually decreased in number and size after 30 days of age. Only a few small inclusions were seen in rats of 35 days of age or older, in spite of continuous injection of the drug. Inclusions gradually decreased in number after discontinuation of the drug in a relatively younger age group. Injection of the drug in adult rats produced only a few small neuronal inclusions. Ultrastructurally, concentrical lamellar structures were the predominant ones in younger age groups but other types of inclusions were seen in older animals and those receiving lesser amounts of the drug or those which were examined after discontinuation of the drug. This observation suggests that morphologically different inclusions can be formed by basically the same treatment if there is any difference in the metabolic activity of the target cell or the amounts of the drug. Biochemical analysis of the sterols revealed a consistently high level of 7-dehydrocholesterol up to 69 days of age, when AY9944 was administered continuously, despite the fact that there was a decrease in the number and size of the abnormal neuronal inclusions.
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  • 26
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    Acta neuropathologica 25 (1973), S. 259-270 
    ISSN: 1432-0533
    Keywords: Tuberous Sclerosis ; Electron Microscopy ; Cerebral Biopsy ; Astrocytes ; Cerebral Tumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The electron microscopic study of a cortical biopsy from a child presenting a Tuberous Sclerosis shows the importance of the astrocytic gliosis, the existence of abnormal cells of which two types can be recognized, and the presence of giant cells. All these cells are remarkable by the abundance of the ergastoplasm, the development of the Golgi apparatus, and the presence of membrane bound dense bodies. These cells are undoubtedly of astrocytic origin and appear very similar to the cells observed in a tumour of the caudate nucleus of another child affected by the same disease. These morphological data lead to believe that the cerebral abnormalities of the Tuberous Sclerosis essentially concern the astrocytes. The main characteristic of this astrocytic lesion would be its blastomatous potentiality.
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  • 27
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    Calcified tissue international 12 (1973), S. 16-29 
    ISSN: 1432-0827
    Keywords: Bone ; Cartilage ; Culture ; Glycosaminoglycans ; Sephadex ; Collagen ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des cultures de monocouches cellulaires d'épiphyses fémorales distales d'embryons de veaux sont étudiées immédiatement après la première sub-culture, réalisée après culture primaire. L'examen au microscope optique classique montre des dépôts disséminés de matériel métachromatique: en microscopie électronique, de fines fibrilles, considérées comme des fibres de collagène, en voie de développement, ont été observées. La nature des sécrétions cellulaires a été étudiée à l'aide de précurseurs radioactifs, fractionnés sur Sephadex G200, ainsi qu'à l'aide de chromatographie par échange d'ions. La digestion enzymatique par hyaluronidase et chondroitinase AC et ABC, bactérienne et testiculaire, démontre que les cellules synthétisent 70% de glycosaminoglycanes sulfatés et 30% de glycosaminoglycanes non sulfatés. Parmi les glycosaminoglycanes, 70% sont constitués par du chondroitine-4-sulfate, 20% par du chondroitine-6-sulfate et le reste probablement par du keratane-sulfate. Les études avec des acides aminés marqués indiquent que les cellules synthétisent une protéine de poids moléculaire élevé, contenant de l'hydroxyleproline, ainsi qu'une protéine non-collagénique, mise en évidence par incorporation de tryptophane.
    Abstract: Zusammenfassung Einschichtige Zellkulturen von der distalen Femurepiphyse von Kalbsembryonen wurden nach der ersten Subkultur untersucht, welche nach der Verschmelzung der primären Kulturen angesetzt wurde. Die lichtmikroskopische Untersuchung zeigte verstreute Ablagerungen von metachromatisch gefärbtem Material; bei der Elektronenmikroskopie wurden feine Fibrillen festgestellt, welche als Collagenvorstufe angesehen wurden. Nach einer Kultur von mehreren Tagen zeigte sich eine lacunäre Anordnung der Zellen. Die Beschaffenheit der Zellsekretionen wurde mittels radioaktiv markierten Verbindungen untersucht, welche auf Sephadex G200 und durch Ionenaustausch-Chromatographie fraktioniert wurden. Die enzymatische Verdauung mit bakterieller und testikulärer Hyaluronidase und Chondroitinase-AC und-ABC zeigte, daß die Zellen 70% sulfatierte und 30% nichtsulfatierte Glycosaminoglycane synthetisierten. Die sulfatierten Glycosaminoglycane enthielten 70% Chondroitin-4-Sulfat, 20% Chondroitin-6-Sulfat, und der Rest war wahrscheinlich Keratansulfat. Untersuchungen mit markierten Aminosäuren-Vorläufern deuteten darauf hin, daß die Zellen ein Hydroxyprolinhaltiges, hochmolekuläres Protein synthetisierten und dazu etwas Eiweiß, bei dem es sich auf Grund des Tryptophaneinbaues nicht um Collagen handeln kann.
    Notes: Abstract Monolayer cell cultures from the distal femoral epiphyses of embryo calves were studied following the first subculture, which was carried out after confluence in primary culture. Light microscopic examination revealed scattered deposits of metachromatic-staining material; on electron microscopy fine fibrils considered to be developmental collagen were seen. After several days in culture lacuna-like patterns of cells were seen. The nature of the cell secretions were studied by radioactive precursors, which were fractionated on Sephadex G200 and by ion exchange chromatography. Enzyme digestion with bacterial and testicular hyaluronidase and chondroitinase-AC and-ABC revealed that the cells synthesized 70% sulphated, and 30% non-sulphated glycosaminoglycans. Of the sulphated glycosaminoglycans 70% was chondroitin-4-sulphate, 20% chondroitin-6-sulphate, and the remainder probably keratansulphate. Studies were labelled amino acid precursors suggested that the cells synthesized a high-molecular weight protein containing hydroxyproline, as well as some non-collagenous protein, shown by tryptophan incorporation
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  • 28
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    Calcified tissue international 13 (1973), S. 83-92 
    ISSN: 1432-0827
    Keywords: Proteoglycan ; Collagen ; Cartilage ; Electron Microscopy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'élimination de protéoglycans solubles de coupes de cartilage costal de boeuf, par extraction dans une solution de 4M d'hydrochlorure de guanidinium, permet de mettre en évidence des quantités abondantes de collagène dispersé et désagrégé dans la matrice. Les protéoglycanes, résistants à l'extraction, sont visibles sous forme de granules concentrés dans les régions périlacunaires. Les granulations plus importants des protéoglycanes semblent venir du chondrocyte. Dans la matrice, éloignée des chondrocytes, ces granules deviennent plus étroites. Un composant non granulaire “amorphe” masque les fibres de collagène, de telle sorte qu'elles sont difficilement visibles dans le cartilage intact.
    Abstract: Zusammenfassung Die löslichen Proteoglycane wurden mittels Extraktion in 4 M Guanidinhydrochlorid aus Rippenknorpelschnitten des Rindes entfernt. Dies erlaubte die Sichtbarmachung von großen Mengen von verstreuten und auseinandergerissenen Collagen in der Matrix. Die Protoglycane, welche sich nicht extrahieren lassen, erscheinen als kleine, in den perilacunären Regionen konzentrierte Körnchen. Die großen Proteoglycan-Körner scheinen in den Chondrocyten zu entstehen. Sobald sie sich in die Matrix, außerhalb der Chondrocyten, verlagern, werden die Körner kleiner. Ein nicht-granulärer, „amorpher” Bestandteil verhüllt die Collagenfasern, so daß diese im intakten Knorpel nicht deutlich gesehen werden können.
    Notes: Abstract Removal of the soluble proteoglycans from slices of bovine costal cartilage by extraction in 4 M guanidinium hydrochloride permitted the visualization of abundant amounts of dispersed and disaggregated collagen in the matrix. Proteoglycans which are resistant to extraction are seen as small granules which are concentrated in the perilacunar regions. Large proteoglycan granules appear to originate in the chondrocyte. As they come to occupy positions in the matrix distant from the chondrocyte, the granules become smaller. A non-granular, “amorphous” component masks the collagen fibers so that they cannot be readily seen in the intact cartilage.
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  • 29
    ISSN: 1432-0827
    Keywords: Amorphous ; Apatite ; Electron Microscopy ; Crystallization ; Precipitation ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Du phosphate de calcium amorphe (ACP) sèché peut se présenter sous forme discoide ou sphérique. Les particules discoides sont plus fréquents dans les specimens d'ACP sèché, isolés immédiatement après précipitation. Les formes sphériques dominent dans les specimens sèchés provenant de suspensions plus âgés. Les particules discoides résultent de la dessication de l'échantillon. Les sphères peuvent aussi se produire pendant la dessication, mais s'observent aussi dans la solution. Les disques et les sphères ont une origine commune sous la forme d'un agrégat d'ACP hautement hydraté de morphologie inconnue. La formation d'apatite cristallin en solution est intimement associée avec l'ACP. Les premiers cristaux apparaissent à la surface des sphères amorphes et en contact avec les disques amorphes. En cas de sphères, les cristaux initiaux augmentent de taille et forment de nouveaux cristaux par nucléation secondaire jusqu'à ce que les sphères soient enrobées par l'apatite. Cependant, lorsque la transformation est totale, l'apatite ne remplit pas l'espace occupé préalablement par les sphères amorphes dissoutes. Ces observations ne confirment pas le concept d'une conversion d'un état solidein situ dans ce cas mais suggèrent une transition hétérophasique d'un processus de translocation ionique par l'intermédiaire d'une solution. La production de cristaux dans les disques amorphes suggère que l'apatite peut aussi se former directement du précurseur dans la solution.
    Abstract: Zusammenfassung Getrocknetes amorphes Calciumphosphat (ACP) kann scheiben- und kugelförmig auftreten. Die scheibenförmigen Partikel herrschen in getrockneten ACP-Proben vor, welche direkt nach der Fällung isoliert wurden. Die kugeligen Formen herrschen in trockenen Proben aus älteren Suspensionen vor. Die Scheibenbildung ist ein Ergebnis des Trocknungsvorganges. Kugelige Formen können beim Trocknungsvorgang ebenfalls auftreten, sie sind aber in der nativen Suspension ebenfalls anwesend. Scheiben- und Kugelformen scheinen einen gemeinsamen Vorläufer in der Lösung zu haben, welcher ein hochhydratisiertes ACP-Aggregat unbekannter Morphologie zu sein scheint. Die Bildung von kristallinem Apatit in der Lösung steht in engem Zusammenhang mit ACP. Die ersten Kristalle erscheinen auf der Oberfläche der amorphen Kugeln und in Kontakt mit den amorphen Scheiben. Die ursprünglichen Kristalle auf den Kugeloberflächen nehmen an Größe zu und bilden durch sekundäre Nukleation weitere Kristalle, bis die Kugeln in Apatit eingehüllt werden. Wenn die Umwandlung abgeschlossen ist, füllt jedoch das Apatit den Platz nicht aus, der vorher von den aufgelösten amorphen Kugeln eingenommen wurde. Diese Beobachtungen bekräftigen die Auffassung einerin situ-Umwandlung in den festen Zustand bei dem beschriebenen Falle nicht, sondern deuten auf eine heterophasischen Übergang, welcher durch einen lösungsbedingten Ionenverschiebungs-Prozeß gefördert wird. Das Auftreten von Kristallen in den amorphen Scheiben deutet darauf hin, daß sich Apatit auch direkt aus dem Lösungsvorläufer bilden kann.
    Notes: Abstract Dried amorphous calcium phosphate (ACP) can exist in discoidal and spheroidal forms. The disk-shaped particles are most prominent in dried ACP specimens isolated immediately following precipitation. The spherical forms become dominant in dried specimens taken from older suspensions. The disk-like morphology is a result of sample drying. Spherules can also arise during the drying step but are present in the native suspension as well. Both the disks and spherules appear to have a common solution progenitor in the form of a highly hydrated ACP aggregate of unknown morphology. The formation of crystalline apatite in solution is intimately connected with ACP. The first crystals appear on the surface of the amorphous spherules and in contact with the amorphous disks. In the case of the spherules, the initial crystals increase in size and generate additional crystals by secondary nucleation until the spherules become enveloped by apatite. However, when conversion is completed, the apatite does not fill appreciably the space previously occupied by the dissolved amorphous spherules. These observations do not support the concept of anin situ solid state conversion in this case, but indicate a heterophase transition supported by a solution-mediated ion translocation process. The occurrence of crystals in the amorphous disks suggest that apatite can also form directly from the solution progenitor.
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  • 30
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    Lung 150 (1973), S. 49-59 
    ISSN: 1432-1750
    Keywords: Pigeon Breeder's Disease ; Electron Microscopy ; Pulmonary Function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of the acute form of pigeon breeder's disease is presented. Electron-microscope studies show the histomorphological substrate of the foreign-body reaction and the immunological cell response caused by the inhaled pigeon material.
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    Lung 149 (1973), S. 181-192 
    ISSN: 1432-1750
    Keywords: Hyperoxia ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die elektronenmikroskopischen Ergebnisse bei Hyperoxie und hyperbarer Oxygenation bestätigen übereinstimmend in der Frühphase an der Lunge die exsudativen Veränderungen mit Endothelschwellung und latentem interstitiellen Ödem. Durch eine deutliche Verbreiterung des Blut-Luft-Weges besteht eine Reduktion in der Diffusionskapazität. Die Störungen in der Permeabilität der Zellmembranen betreffen zunächst mehr das Capillarendothel als das Alveolarepithel. Für das Auftreten der Zellschäden ist die Höhe des Saurerstoffpartialdruckes entscheidender als die hyperbare Oxygenation. Die Einatmung von reinem Sauerstoff im Überdruck führt zusätzlich über einen Anstieg des Kohlensäurepartialdruckes im Gewebe zu einer neurochemisch ausgelösten akuten Hypertension mit Lungenödem (Wood und Perkins, 1970). Das Lungenödem bei Hyperoxie und hyperbarer Oxygenation kommt sehr wahrscheinlich auf mehreren pathogenetischen Wegen zustande. Atelektasen bei Hyperoxie sind wahrscheinlich durch die Exsudation von fibrinmonomerhaltigem Blutplasma mit nachfolgender Inaktivierung vorhandener Surfactant-Aktivitäten sowie durch die Blockade der intracellulären Synthese des Surfactant ausgelöst. Zusätzlich sind direkte Enzymschäden der Zelle nach Sauerstoffvergiftung, besonders die Wirkungen der Peroxydationen auf die Mitochondrienmembranen zu berücksichtigen (Haugaard, 1968; Podlesch, 1972; Kleinschmidt, 1972). Der Schweregrad der Diffusionsstörung ist vom O2-Partial-druck und von der Expositionsdauer abhängig. Hibernation retardiert die Sauerstofftoxizität (Huizenga, Butcher und Simmonds, 1972). Die Lungen kleinerer Laboratoriumstiere reagieren schneller und empfindlicher auf O2-Schäden als die Lungen größerer Laboratoriumstiere und als die Lunge des Menschen. Kurzfristige Intervallbeatmung von 40%igem Sauerstoff im Inspirationsgemisch ist unschädlich und ruft keine Lungenveränderungen hervor. Trifft dagegen eine länger angewandte Hyperoxie auf eine vorgeschädigte Lunge, z. B. bei Schocksyndrom, Fettembolie oder Lungentrauma, müssen sich die Schäden aggravieren und können unter dem Bild eines progressiven Atemnotsyndroms zum Tode führen. Hyperoxische Lungenschäden benötigen aufgrund der elektronenmikroskopischen Befunde mehrere Monate bis zur anatomischen Ausheilung, wobei die Wiederherstellung der Lungenfunktion der anatomischen Ausheilung vorangeht.
    Notes: Abstract The results of electron microscope examinations during hyperoxia and hyperbaric oxygenation unanimously confirm the exudative changes in the lungs in the early stages, with endothelial swelling and latent interstitial oedema. Because of marked spreading of the blood-air paths, a reduction occurs in the diffusion capacity. Disturbances in the permeability of the cell membrane involve the capillary endothelium at first more than the alveolar epithelium. The level of the oxygen partial pressure is more decisive than hyperbaric oxygenation for the appearance of cell damage. Inspiration of pure oxygen at excess pressure also causes neurochemically induced acute hypertension with pulmonary oedema due to an increase in the partial pressure of carbon dioxide in tissues. Probably several pathogenic pathways are involved in the formation of pulmonary oedema in hyperoxia and hyperbaric oxygenation. In hyperoxia, atelectases are probably produced by the exudation of blood plasma containing fibrin monomer with subsequent inactivation of the surface activity present and by the blockade of the intracellular synthesis of surfactant. In addition, direct damage to cell enzymes after poisoning with oxygen, especially the effect of peroxidation on the mitochondrial membranes must be taken into account. The degree of severity of diffusion disturbance depends on the O2 partial pressure and on the duration of exposure. Hibernation delays the toxicity of oxygen. The lungs of smaller laboratory animals react more quickly and more sensitively to the harmful effects of O2 than the lungs of larger laboratory animals and man. Short periods of artificial respiration at intervals, with 40% oxygen in the inspiration mixture, are harmless and cause no changes in the lungs. However, if hyperoxia is used for a longer period, on a previously damaged lung, for example in shock, fat embolism or lung trauma, the damage becomes worse and may end in death resulting from progressive dyspnoea. The electron microscope findings show that in hyperoxic lung damage, several months are required for anatomical cure, the restoration of lung function preceding the anatomical cure.
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    European archives of psychiatry and clinical neuroscience 218 (1973), S. 79-91 
    ISSN: 1433-8491
    Keywords: Storage Disease ; Juvenile Amaurotic Idiocy ; Curvilinear Bodies ; Electron Microscopy ; Rectal Biopsy ; Speicherkrankheit ; Juvenile amaurotische Idiotie ; Curvilineäre Körper ; Elektronenmikroskopie ; Rectum Biopsie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei einem Fall von juveniler amaurotischer Idiotie mit protrahiertem Verlauf (Beginn der Erkrankung mit 14 Jahren, Alter des Patienten 52 Jahre) wird über die Ultrastruktur des Speichermaterials in einer Rectumbiopsie berichtet. Das in Makrophagen der Mucosa gespeicherte Material entspricht den für die juvenile Form charakteristischen curvilineären Strukturen. Gegenüber der Kufsschen Form läßt sich der Fall ultrastrukturell durch das Fehlen der bei der Spätform beschriebenen Lipofuscin-Granula abgrenzen. Das klinische Bild spricht auch für die juvenile Form. Auffallend waren neben dem protrahierten Verlauf der verzögerte Beginn der Erkrankung sowie das späte Einsetzen der geistigen Retardierung.
    Notes: Summary The ultrastructure of storage material in a rectal biopsy taken from a patient with juvenile amaurotic idiocy with protracted course (onset of illness: 14 years; age of patient: 52 years) is described. The material stored in macrophages of the mucosa was like the curvilinear structures characteristic of the juvenile type. It was possible to exclude Kufs' type in this case by absence of the lipofuscin granula seen in the fine structures in the adult type. The clinical picture was also consistent with the juvenile form. Apart from the protracted course, other striking features were the delayed onset of the disease and the late beginning of mental retardation.
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    Pflügers Archiv 340 (1973), S. 361-366 
    ISSN: 1432-2013
    Keywords: M. rectus abdominis ; Slow Fibres ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Out of 253 muscle fibres taken from various parts of frog rectus abdominis muscles 52 were identified electron microscopically as slow. 48 slow fibres were localized at the ventral surface and at the linea alba. No evidence was found for the existence of a fibre type with structural features different from typical twitch or slow fibres.
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    Cell & tissue research 136 (1973), S. 19-30 
    ISSN: 1432-0878
    Keywords: Autonomic innervation ; Uterus ; Oviduct ; Adrenergic, Cholinergic ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the preterminal nerve fibers of the rabbit myometrial smooth muscle was studied using potassium permanganate fixation or glutaraldehyde fixation with postosmification. The preterminal fibers were mostly formed by 2–10 axons enveloped by Schwann cells. Two kinds of axons and axon terminals were found. (1) Adrenergic axons, which contained many small, granular vesicles (diameter 300–600 Å) and large granular vesicles (diameter 700–1200 Å) which represented ca. 2% of the total count of the vesicles. (2) Nonadrenergic axons, which contained small agranular vesicles (diameter 300–600 Å) and large granular vesicles (diameter 700–1200 Å). Both types of axons formed preterminal varicosities along their course. The real terminal varicosities, representing the anatomical end of the axons, were usually larger than the preterminal ones and showed close contact to the plasma membranes of the smooth muscle cells. Both adrenergic and nonadrenergic terminals were found close to the smooth muscle cells, but a gap of at least 2000 Å was always present between the two cell membranes. The axons and preterminal varicosities of both types of nerves were in intimate contact with each other within the preterminal nerve fiber. Axo-axonal interactions between the two types of axons are possible in the rabbit myometrium. The relative proportion of the nonadrenergic axons from the total was about one fourth.
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  • 35
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    Cell & tissue research 136 (1973), S. 569-578 
    ISSN: 1432-0878
    Keywords: Myoepithelium ; Bryozoaire (Alcyonidium polyoum) ; Vacuole ; Striated muscle, muscular insertion ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'épithélium pharyngien d'Alcyonidium polyoum possède des cellules pourvues d'une très grande vacuole. L'incompressibilité du liquide vacuolaire permet un élargissement brusque de l'organe lors de la contraction du manchon musculaire strié qui enserre cette vacuole. Les fibres musculaires sont insérées sur le plasmalemme apical par des filaments unitifs. Le point d'attache est relié à la lame amorphe du cell-coat qui entoure les microvillosités par des fibrilles, réalisant probablement une liaison mécamique plus efficace. Le reticulum sarcoplasmique porte des ribosomes. Le cytoplasme apical renferme des vésicules de diverses catégories.
    Notes: Summary Pharyngeal cells of Alcyonidium polyoum (Bryozoa) are provided with very large vacuoles. Each vacuole is enveloped by a thin layer of striated muscle, whose contraction enlarges the organ. Filaments join the muscular elements to the apical plasmalemma. This point of muscular insertion is connected by fibrils with the amorphic lamina of cell-coat which surrounds the microvilli. Ribosomes are often found on dyads. Various vesicles are located in the apical cytoplasm.
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  • 36
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    Biotechnology and Bioengineering 15 (1973), S. 129-142 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Methods for the production of protein concentrates, with a low content of nucleic acid, in kilogram quantities from yeast have been studied with the aid of equipment designed for operation on pilot-plant scale. The influence of drum drying and mechanical disintegration on the nutritive value of the yeast was also investigated. Drum drying and mechanical disintegration improved the nutritive value of the yeast but high extractability of protein and nucleic acid was only obtained after mechanical disintegration.Protein concentrates without and with cell walls were produced from mechanically disintegrated yeast. The different fractions which were obtained when separating cell walls and precipitating protein by heating at alkaline pH, were analyzed. After protein precipitation, about 90% of the RNA could be precipitated from the supernatant by addition of acid, giving a product containing 50% RNA of the dry weight. The protein precipitate obtained after cell wall separation had an RNA content of less than 2% and contained 70-l75% of the amino acids in the starting yeast material. Protein concentrates containing cell walls were produced by precipitating protein by heating at alkaline pH directly after mechanical disintegration. The content of RNA was about 2% and the yield of amino acids was 70-80%. It was found that the nutritive value of the protein concentrate was higher than that of the starting yeast material. To produce such a protein concentrate on a large scale, the process described can probably be employed.
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    Biotechnology and Bioengineering 15 (1973), S. 197-200 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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    Biotechnology and Bioengineering 15 (1973) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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    Biotechnology and Bioengineering 15 (1973), S. 225-237 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Xanthan gum, a heteropolysaccharide with unusual and useful properties, is now produced commercially by fermentation with Xanthomonas compestris NRRL B-1459 in a medium containing glucose, minerals, and a complex nitrogen source - distillers' dried solubles (DDS). Understanding the kinetics of the fermentation should contribute to process improvements and increase the market potential for the gum. Earlier studies showed that although DDS determined initial growth rate, growth was stopped by some mechanism other than substrate exhaustion, probably an effect related to product formation.Product formation did not require active growth, but its rate increased with cell concentration. Specific product formation rate declined at high viscosities. Varying glucose concentration from 0.5 to 5.0% and dissolved O2 tension between 20 and 90% air saturated had no effect on the rates, but pH had to be maintained near 7 and temperature near 28°C to permit continued product formation. Xanthan yield could be explained by the energy required for growth and polymerization, that energy coming from dissimilation of the part of the carbohydrate substrate not converted to polymer.
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    Biotechnology and Bioengineering 15 (1973), S. 783-794 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Barely β-amylase (α-1,4-glucan maltohydrolase, EC 3.2.1.2) has been immobilized by covalent fixation to amino derivatives of epichlorohydrin crosslinked Sepharose mediated by cyclohexyl isocyanide and acetaldehyde. The enzyme conjugates contain up to 35% of the total activity of the β-amylase added to the coupling mixture. The profiles of activity versus pH and ionic strength are essentially the same for free and immobilized β-amylase, whereas the resistance to inactivation during storage and use is considerably enhanced by immobilization. Columns with immobilized β-amylase have been used for continuous degradation of starch. At 45°C, half of the initial activity remains after seven weeks, and the corresponding figure at 23°C is 85 percent.
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  • 41
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    Biotechnology and Bioengineering 15 (1973), S. 827-829 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Tab.
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  • 42
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    Biotechnology and Bioengineering 15 (1973), S. 845-859 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Of 24 different polymer and surfactant materials examined, a carboxypolymethylene (“Carbopol”) was found to cause enhancement of respiration rates in an Aspergillus niger culture by as much as 200%. Enhancement of other fermentation parameters, such as cellular growth and amylase production, was also observed.The enhancement effects of Carbopol were examined with clusters of spores and mold pellets. In the first case, it appears that the ionized carboxyl groups of Carbopol induced electrostatic repulsion among the spores thus initiating pulp growth with increased interfacial area of contact between the mold and the nutrient medium. In the second case, the Carbopol additive formed a thin film attached to the surface of the pellets which seemed to be responsible for an increased rate of potassium transport and, hence, fermentation yields. Additive utilization as substrate and physiological changes in the culture were not observed in these cases.It was also found that the probability of pellet formation, the size of pellets formed, and the number of spores per pellet can be correlated to the energy input to the fermentation system.
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    Biotechnology and Bioengineering 15 (1973), S. 879-888 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The steady state, nonlinear diffusion equations which describe reactions in constrained enzyme solutions are of great interest in many biological and engineering applications. As in other types of nonlinear differential equations, exact analytical solutions do not exist except in some simplified cases. In this paper, a general procedure is presented for solving numerically for the substrate concentration profile and effectiveness factor utilizing the transformation method suggested by Na and Na. Design correlations for enzyme solutions constrained within spherical membranes are included. The use of a unique definition of the Thiele Modulus in these charts permits the clear illustration of the effects of substrate concentration and external mass transfer resistances on the overall effectiveness factor for the catalyst particle.
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  • 44
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    Biotechnology and Bioengineering 15 (1973), S. 1023-1037 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies are reviewed on the composition of hemolymph from Japanese beetle larvae, Popillia japonica. This research was conducted to determine the chemical environment required for sporulation of the milky disease organism, Bacillus popilliae. Amino acids, proteins, organic acids, lipids, carbohydrates, and oxygen content were determined in hemolymph from healthy and diseased larvae. Oxygen content of hemolymph was measured by microelectrodes implanted in the hemocoel of living larvae. Vegetative growth of the pathogen reduces the dissolved oxygen; however, as sporulation occurs, oxygen concentration approaches normal values. Trehalose, the major hemolymph sugar, is reduced by ca. 50% during the course of milky disease. Neutral lipids, phospholipids, and hydrocarbons decrease markedly with infection. Both branched-chain and normal alkanes occur in hemolymph. Milky disease causes an increase in concentration of pyruvic, malic, glycolic, tartaric, and glyoxylic acids. The major hemolymph protein, a lipoglycoprotein, has a mol. wt. of ca. 500,000. Reduced concentration of this protein is accompanied by the appearance of a smaller protein. Amino acids that increase significantly as a result of infection are: Glutamic acid, aspartic acid, β-alanine, phenylalanine, threonine, lysine, and serine. Hemolymph contains few peptides of low molecular weight.
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  • 45
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    Biotechnology and Bioengineering 15 (1973), S. 1123-1129 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Cellulase production by strains of Myrothecium verrucaria, Stachybotrys atra and Trichoderma viride was examined. Myrothecium verrucaria was found to give the greatest yields. A variety of media were examined as potential substrates for the industrial production of cellulase. The salts content of the medium was varied and was found to affect cellulase production. Glucose, carboxymethylcellulose (CMC), filter paper and three industrial wastes were examined as possible cellulase inducers. Filter paper was found to be the most effective, followed by sugar cane bagasse and CMC.
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  • 46
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    Biotechnology and Bioengineering 15 (1973), S. 1189-1192 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
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  • 47
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    Biotechnology and Bioengineering 15 (1973) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 48
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    Biotechnology and Bioengineering 15 (1973), S. 85-91 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Flavor enhancing nucleotides may be produced by streptomycetes. Mutants of streptomyces 772 were found to produce, under ordinary fermentation conditions, considerable amounts of 5′-IMP and 5′-XMP, but only traces of 5′-GMP. This was probably due to the feedback inhibition of the end product GMP. It was shown that through suitable fermentation techniques it was possible to overcome this internal control mechanism, leading to increased yields of 5′-GMP.
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  • 49
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    Biotechnology and Bioengineering 15 (1973), S. 143-161 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Quantitative studies are reported of external film and internal pore diffusion effects for glucose oxidase immobilized on porous glass in a continuous, tubular, packed bed reactor. The McCune and Wilhelm model for external film diffusion is shown to describe these data over a particle Reynolds number range from 0.2 to 25. The Thiele analysis provides a good description of internal pore diffusion resistances. It appears that immobilized enzymes free of internal diffusional restrictions generally require the use of supports with pore sizes larger than those currently available in porous glass.
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  • 50
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    Biotechnology and Bioengineering 15 (1973), S. 201-206 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
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  • 51
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    Biotechnology and Bioengineering 15 (1973), S. 933-949 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The response of aerobically growing heterogeneous microbial populations of sewage origin to step increases and decreases in pH were studied in both once-through and cell recycle systems. The pH range studied was 2.7 to 8.0. All studies were conducted at a dilution rate of 0.125 hr-1, and all shocks were administered from a base or preshock pH level of 6.4 to 6.7. In each experiment, the preshock or initial “steady state” was assessed, the pH of the feed changed, and the resulting transient behavior of the system examined until attainment of the new or final “steady state” was approached. The major objectives of the work were to characterize the nature of the response with respect to biomass and effluent substrate concentrations, types of microbial populations present and chemical composition of the biomass, and to obtain guidelines as to allowable change in pH in waste streams. It was found in once-through systems that substrate removal efficiency recovered from pH levels as low as 3.0 after rather long periods of transient leakage of substrate. Cell recycle attenuated the severity of substrate leakage. In all cases of severe acid shock, the microbial population changed from predominantly bacterial-protozoan to one consisting predominantly of filamentous fungi. Changes in chemical composition of the sludge (protein and carbohydrate content) were consistent with the population changes. Based upon the results, it can be conservatively estimated that changes in pH of no more than one unit from the neutral preshock range can be tolerated without possible disruption of biochemical efficiency of substrate removal.
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  • 52
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    Biotechnology and Bioengineering 15 (1973), S. 981-992 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Wheat germ agglutinin protein, which is able to agglutinate tumor cells better than normal cells, was covalently bound to polyacrylamide gel beads. The specific binding activity of the protein was preserved on these beads and was expressed heterogeneously by the binding of mouse leukemia cells (L1210) to the protein coupled gels. The selective activity of the immobilized protein was maximal when the number of sites available to covalently couple the protein was lowest. The application of this observation to the general field of covalent immobilization of proteins and enzymes may be of considerable utility.
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  • 53
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    Biotechnology and Bioengineering 15 (1973), S. 1011-1016 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 54
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    Biotechnology and Bioengineering 15 (1973), S. 1039-1044 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It is sometimes easier and cheaper to extract a drug's target sites from cells than it is to purify, concentrate or manufacture the drug itself. This is especially true in the case of DNA and some of the exotic antibiotics that react with it. Phleomycin, an inhibitor of replication, was considered as a specific case in point. Biologically active components of this antibiotic mixture bind nondestructively to DNA, in vitro and in vivo, and thereafter may be processed by simple, economical methods usually reserved to macromolecules of much greater size.
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  • 55
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    Biotechnology and Bioengineering 15 (1973), S. 1081-1088 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A procedure for the preparation of about 50 g batches of tRNA from 25 kg E. coli W is described. The method involves phenolic extraction of the cells, batch absorption of the tRNA on DEAE-cellulose, washing the DEAE-cellulose and packing it into a column, elution of the tRNA from the column and precipitation of the tRNA with ethanol. The method is less time and labor consuming than the methods described in the literature and can be carried out with relatively simple equipment.
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  • 56
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    Biotechnology and Bioengineering 15 (1973), S. 1131-1145 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Several techniques for investigating the multiplicity and stability of open isothermal enzymatic reactors are discussed and some of the pitfalls in previous thinking pointed out. The example which is used to illustrate these methods exhibits several interesting features. Among these is the existence of a stable oscillatory state which surrounds a unique steady state which is asymptotically stable to certain finite disturbances.
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  • 57
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    Biotechnology and Bioengineering 15 (1973), S. 1159-1177 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simplified model of cell metabolism, consisting of a series of linked reversible enzymatic reactions dependent on the concentration of a single external substrate has been developed. The general mathematical solution for this system of reactions is presented. This general solution confirms the concept of a rate-limiting step, or “master reaction”, in biological systems as first proposed by Blackman. The maximum rate of such a process is determined by, and equal to, the maximum rate of the slowest forward reaction in the series.Of practical interest in modeling the growth rate of cells are three cases developed from the general model. The simplest special case results in the Monod equation when the maximum forward rate of one enzymatic reaction in the cell is much less than the maximum forward rate of any other enzymatic reactions.More realistic is the case where the maximum forward rates of more than one enzymatic reaction are slow. When two slow enzymatic reactions are separated from each other by any number of fast reactions that overall can be described by a large equilibrium constant, the Blackman form results: \documentclass{article}\pagestyle{empty}\begin{document}$$\mu = [S]/A, \rm{when} [S] 〈 A\mu_{\rm{max}}$$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$$\mu = \mu_{\rm{max}}, \rm{when} [S] \rm{〉} A\mu _{\rm{max}}$$\end{document}A third case is that in which two slow enzymatic steps are separated by an equilibrium constant that is not large. Unlike the Monod and Blackman forms, which contain only two arbitrary constants, this model contains three arbitrary constants: \documentclass{article}\pagestyle{empty}\begin{document}$$[S] = \mu A + \frac{{\mu B}} {{(\mu_{\rm{max}} - \mu)}}$$\end{document}The Monod and Blackman forms are special cases of this three constant form.In comparing equations with two arbitrary constants the Monod equation gave poorer fit of the data in most cases than the Blackman form. It is concluded that workers modeling the growth of microorganisms should give a t least as much consideration to the Blackman form as is given to the Monod equation.
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  • 58
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    Biotechnology and Bioengineering 15 (1973), S. 47-67 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Immobilized invertase was prepared by binding native invertase to a polyamine type ion-exchange resin. Kinetic behavior of the immobilized invertase on these small pellets was investigated in a packed-bed reactor. For low flow rates, an effect of interparticle diffusion on the Machaelis constant was observed and a correlation was proposed to evaluate the effect. At high flow rates, Michaelis and inhibition constants were determined and compared with those for native invertase. With large pellets, intraparticle diffusion was found to be important and at high substrate concentrations, the effectiveness factor exceeded unity. Good agreement was found between the theoretical analyses and the experimental data.
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  • 59
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    Biotechnology and Bioengineering 15 (1973), S. 271-283 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A process for the large-scale isolation of choline acetyltransferase from ox brain has been developed, by scaling-up an existing laboratory method. 20% of the enzyme was obtained from 17 kg of brain tissue with a 50-fold purification.
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  • 60
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    Biotechnology and Bioengineering 15 (1973), S. 299-308 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effect of potassium sorbate addition to a continuous culture of Saccharomyces cerevisiae was observed. The influence on the yeast performance depended on the way the inhibitor was added. The unsteady state continuous method seems to be the best one to obtain microorganisms' adaptation to inhibitors, and for the experimental study of microbial inhibition.
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  • 61
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    Biotechnology and Bioengineering 15 (1973), S. 359-375 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: New methods of crosslinking enzyme molecules inside a matrix with or without an inactive protein are described. Enzyme activity yields range between 30 and 80% of the activity of the untreated preparations. Even fragile enzyme systems, for instance those using mobile cofactors, can be efficiently immobilized. Increased resistance towards heat denaturation and proteolysis results.
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  • 62
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    Biotechnology and Bioengineering 15 (1973), S. 493-503 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Penicillin amidase, an enzyme which hydrolyzes benzylpenicillin to 6-aminopenicillanic acid and phenylacetic acid, is produced by Bacillus megaterium ATCC 14945 as an extracellular enzyme. We used this system as a model to examine the effects of nitrogen, sulfur, and phosphorous limitation on enzyme production in continuous culture. For these studies, we developed a minimal medium for B. megaterium which contained histidine as the sole nitrogen source. Batch experiments showed that this enzyme is produced as a growth-associated metabolite. Enzyme production was shown to be a function of the growth-limiting conditions and the concentration of the inducer, phenylacetic acid. Sulfur limitation in continuous culture yielded enzyme activities approximately three to five times those observed in nitrogen- and phosphorous-limited chemostats. These results are discussed in terms of the environment's influence on enzyme production in continuous culture.
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  • 63
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    Biotechnology and Bioengineering 15 (1973), S. 533-549 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A periodic countercurrent whole beer process was developed for the recovery of novobiocin to eliminate the high cost of mycelium filtration and accompanying antibiotic losses in the filter cake. In such a process screened, but unfiltered, novobiocin fermentation beer is contacted with a special grade of an anionic-exchange resin in a series of specially designed, well mixed columns. Each column is fitted with a screen sized to retain resin within the column but allow the cells to press. Periodically the lead column is isolated from the column train, washed free of beer solids, and eluted. A freshly eluted column is placed in the trail position to allow countercurrent operation. The eluate is then processed to crystalline product.A mathematical model for the sorption of novobiocin was developed based on a suitable continuity equation and mass transfer and equilibrium relationships determined in the laboratory. Digital computations of this model correlated well with laboratory and pilot plant data, and predicted well the performance of the production units. This simulation has been in continued use to predict and reoptimize plant operation as process changes (such as improved beer titers, increased production rate, and the evaluation of superior ion-exchange resins) occurred or were anticipated.
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  • 64
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    Biotechnology and Bioengineering 15 (1973), S. 603-606 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 65
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    Biotechnology and Bioengineering 15 (1973), S. 589-596 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 66
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    Biotechnology and Bioengineering 15 (1973), S. 729-741 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Twenty-eight Penicillium cultures were screened for dextranase activity. Dextranase yield of about 2000 DU/ml was obtained with Penicillium funiculosum SH-5. Maximum dextranase concentration was attained only when cell mass decreased. The kinetics of the dextranase production was correlated with the cell mass by a two-parameter model. The optimum pH and temperature for dextranase were 5.0-5.5 and 55°C, respectively. Crude dextranase preparation was inhibitory to insoluble glucan formation by streptococcus mutans 6715 in vitro.
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    Biotechnology and Bioengineering 15 (1973), S. 811-815 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 68
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    Biotechnology and Bioengineering 15 (1973) 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
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  • 69
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    Biotechnology and Bioengineering 15 (1973), S. 897-903 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experiments are reported in which a mixed population of organisms was continuous cultured on phenol in a 1- to 2-liter well-mixed vessel. Steady state phenol concentrations were measured for a range of inlet concentrations from 100 to 800 mg/liter at various dilution rates. These results were compared with those predicted from a model which incorporates the effect of wall growth. It was found that the effect of growth on the walls of the vessel was considerable and increased by a factor of up to 3 × the dilution rate at which 90% conversion of phenol could be obtained.
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  • 70
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    Biotechnology and Bioengineering 15 (1973), S. 927-932 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bacteriophage Φ × 174 was produced in 20 and 200 liter fermentors. The phage was concentrated without any loss of infectivity by precipitation with 10% (w/v) Poly(ethylene glycol) 6000 in 0.5M NaCl. The total yield of a 100 liter culture is around 1016 infectious particles. The final purification step in a CsCl gradient results in a 60 to 80% inactivation.
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  • 71
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    Biotechnology and Bioengineering 15 (1973), S. 963-972 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In order to minimize product toxicity, decrease fermentation cost, prolong the effective production phase, and shorten the lag phase before production in the citrate-hydrocarbon fermentation by Candida lipolytica ATCC 8661, the use of a nonsterile semicontinuous cell recycle system was investigated. Model experiments demonstrated that portions of the fermentor broth could periodically be removed and centrifuged under nonaseptic conditions with the cells being added to fresh medium and returned to the fermentor. Citrate production continued, however with repeated semicontinuous cell recycle, acid production gradually decreased. It was postulated that this decrease could be attributed largely to physiological trauma and that a truly continuous cell recycle system would minimize these effects and permit maintenance of higher citrate production rates.
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    Biotechnology and Bioengineering 15 (1973), S. 1017-1017 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 73
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  • 74
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    Biotechnology and Bioengineering 15 (1973), S. 1075-1080 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The isolation and structure determination of a new microbial product, (+)- (123/45)-2,3,4,5-tetrahydroxy-1-cyclohexanemethanol is described. This product was detected in the fermentation broth of a newly isolated actinomycete by its antibacterial activity. A novel isolation method was developed and crystalline product was obtained in good yield. The structure was determined by spectroscopic examination of the product and its acetyl and trimethylsilyl derivatives. The racemic form of this compound had already been synthezised by G. E. McCasland et. al., as analog of galactose.
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    Biotechnology and Bioengineering 15 (1973), S. 1101-1121 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The dynamic behavior of a laboratory-scale activated sludge biological waste treatment process with recycle and wasting of sludge was investigated by subjecting the system to step changes in the influent waste concentration, the recycle flow rate, or the sludge wasting rate. The dynamic behavior of the system was examined by measuring adenosine triphosphate (ATP) in addition to dissolved chemical oxygen demand (COD) and cell dry weight in the aeration tank. Cell dry weight of the recyle flow and effluent COD were also measured.Analysis of the results and estimation of time constants assuming first order responses showed that the time constants characterizing the dynamic responses of the sludge were directly related to the sludge mean residence time. The time constants estimated from dissolved COD measurements were of the same order of magnitude as the fluid residence time in the aeration tank. The ATP transient response was frequently different from that of the cell dry weight in the aeration tank.
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  • 76
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    Biotechnology and Bioengineering 15 (1973), S. 1179-1188 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mutant of E. coli constitutive for β-galactosidase has been grown in batch culture with the carbon source, glycerol, fed at various fixed rates to the culture. High feeding rates where growth was only slightly restricted gave final enzyme levels similar to those obtained in cultures where all the glycerol was added initially. Low feeding rates resulted in breakdown of the β-galactosidase formed and gave reduced final levels of the enzyme.
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  • 77
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    Biotechnology and Bioengineering 15 (1973), S. 1-12 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The known species of yeasts produce at lest 180 different polysaccharides having mannose as a major constituent. The type of mannan formed is characteristic of the yeast species, and can be used as an aid in identification and classification. The immunological characteristics of yeasts depend largely upon the nature of the mannans. Some of the yeast mannans can be produced in relatively high yields, and have been suggested as replacements for plant and bacterial gums as thickeners, dispersing agents, and similar applications. However, more significant uses, based on the finer differences in their chemical structures and the specific reactions they undergo, may result from a closer study of these polymers.
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  • 78
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    Biotechnology and Bioengineering 15 (1973), S. 93-115 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Collagen was used as carrier for the immobilization of invertase, lysozyme, urease, glucose oxidase, penicillin amidase, and glucose isomerase. Immobilization was accomplished by either impregnation of a preswollen collagen membrane with enzyme solution or electrocodeposition of collagen and enzyme from a collagen dispersion containing dissolved enzyme. The collagen-enzyme complexes prepared are in membrane form.Membranous collagen-enzyme complexes were used to construct biocatalytic reactors such as the capillaric coil modular reactor. Such biocatalytic reactors were used in a recirculation system for the conversion of substrates. The biocatalytic reactors showed initial decreases of activity to stable limits which are maintained over a large number of reactor volume replacements. The stable limits correspond to approximately 35% of the initial activities for lysozyme and invertase, 25% for urease, 15% for glucose oxidase.The mechanism of complex formation between collagen and enzyme involves multiple salt linkages, hydrogen bonds, and van der Waals interactions. This protein-protein interaction which leads to stable complexes by both impregnation and electrocodeposition processes is unique among the enzyme immobilization methods currently available.
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  • 79
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    Biotechnology and Bioengineering 15 (1973), S. 163-179 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Kinetic studies on the growth of Aspergillus strains as well as constitutive and inductive polygalacturonase formation have been made in bath fermentations, without pH control. Equations describing growth and product formation of the four-stage growth of microorganisms were applied for the first time to diauxic growth and enzyme formation of Aspergillus strains. Diauxic growth of the cultures has been found in both sucrose- and peetin-containing media. Enzyme concentration in the second transient phase, calculated by the use of new equations, proved to be negligible. In the exponential and declining phases, the calculated values of mycelial and enzyme concentrations were in good agreement with the values observed. Types of classification of the product formation of Luedeking and Piret refer to the second cycle of diauxie. The types of product formation described by Kono and Asai and Luedeking and Piret are mostly in good agreement with each other. The greatest difference has been found in the case of inductive endo-polygalacturonase formation, where the final enzyme formation could not be plotted because of the decrease (autolysis) in mycelial weight.
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  • 80
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    Biotechnology and Bioengineering 15 (1973), S. 207-211 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 81
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    Biotechnology and Bioengineering 15 (1973), S. 693-705 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The use of an air operated extreme pressure hydraulic pump for continuous cell disintegration is described, together with figures obtained for soluble protein released from suspensions of commercially obtained baker's yeast (Saccharomyces cerevisiae).
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  • 82
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    Biotechnology and Bioengineering 15 (1973), S. 677-692 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Eighteen ultrafiltration membranes ranging in molecular weight cutoff ratings from 500 to 300,000 were tested with water, 0.5M NaCl solution, and, in some cases, with macromolecules and urea in a 3-in. stirred filter cell. Approximately half of the membranes showed a significant decrease in filtration rate during the first 24-hr period. The steady-state rates were less than the manufacturers' rating for about two thirds of the membranes, the discrepancy being greater for the membranes with high molecular weight cutoffs.The filtration rates were linearly dependent on applied pressure over the range at least as great as 15 to 55 psig. The rate decreased as the concentration of macromolecules such as transfer ribonucleic acid (tRNA) increased; the rate for a concentration of 3 mg tRNA/per ml was one-fourth of that observed when no tRNA was present. Some increase in rate (∼33 to 50%) was obtained by increasing the stirring speed from 100 rpm to 1000 rpm.The membranes were effective for desalting and concentration of macromolecules but not for separation of large molecules from each other, such as tRNA from bovine serum albumin. Easily denatured molecules such as catalase were not deactivated by filtration at 4°C.
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  • 83
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    Biotechnology and Bioengineering 15 (1973), S. 707-728 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The predation of bacteria by protozoan in both continuous and batch cultures was studied using experimental and modeling techniques. The predator organism was the ciliate, Tetrahymena pyriformis. The bacterium, Aerobacter aerogenes, served as the prey. Several batch growth responses were observed each initiated at a different nutrient level. Continuous cultures were conducted over a range of dilution rates. The models studied were partially successful in simulating the empirical data. Deviations between the model and the actual population behavior are discussed and possible explanations for the differences proposed.
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  • 84
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    Biotechnology and Bioengineering 15 (1973), S. 817-818 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
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  • 85
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    Biotechnology and Bioengineering 15 (1973), S. 821-825 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 86
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    Biotechnology and Bioengineering 15 (1973), S. 861-877 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of C. tropicalis growth were investigated with pure n-hexadecane as dispersed phase substrate. Two distinct growth phases were found: In the first phase, exponential growth was independent of stirrer speed. The onset of the second phase, one of linear growth, was determined by stirrer speed. By the use of two different fermenter types, it was shown that the drop size of the dispersed phase was not primarily responsible for the observed kinetics. It was considered that the formation of biological flocs determined the observed growth pattern. This was substantiated by the results of continuous cultures in the different fermenter types, with various substrate concentrations.
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  • 87
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Lactate dehydrogenase (LDH) and pyruvate kinase (PK), immobilized on solid glass beads by diazotization, were used in packed bed reactors to analyze for both pyruvate (PYR) and phosphoenolpyruvate (PEP) through the disappearance of β-nicotinamide adenine dinucleotide (NADH) monitored spectrophotometrically at 340 nm. Packed bed reactors containing PK and/or LDH were also capable of monitoring continuously varying concentrations of adenosine-5′-diphosphate (ADP), PEP, and PYR. The immobilized enzymes (∼40 μg/g glass) retained about 4% of the activity of the soluble enzymes. Preparations of immobilized LDH and PK exhibited enhanced stability when maintained in the presence of β-mercaptoethanol and NADH or EDTA, respectively, and were shown to regain 75% of the original activity after four months storage at 4°C.
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  • 88
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An investigation was made on the factors influencing the acetic acid concentration in the culture liquid of the aerobic fermentations where acetie acid was used as a carbon source. The acetic acid concentration in the culture liquid changed in proportion to the amount of unutilizable acid or base supplied. This was explained by the principle of conservation of electroneutrality.Another factor affecting the acetic acid concentration in the culture liquid was bicarbonate ions which were formed by the dissolution and dissociation of carbon dioxide in the gas phase of the fermentor. The increment in bicarbonate ion concentration was equal to the decrement in the acetie acid concentration in the culture liquid.
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  • 89
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    Biotechnology and Bioengineering 15 (1973), S. 1193-1197 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
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  • 90
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    Biotechnology and Bioengineering 15 (1973), S. 331-358 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Insofar as saturation kinetics are applicable to the growth of phytoplankton in laboratory experiments and to growth in nature, the computer modeling of intracellular nutrient partitioning in populations of cells can lead to better understanding of the dynamics of natural populations.A three-compartment mathematical model was developed to represent a phytoplankton population having the capability to store nitrogen in a nitrate-limited environment. Parameters were estimated by fitting the model to data from two chemostat experiments reported by Caperon (1968). The model was used to simulate growth dynamics observed in chemostat and batch experiments. The model demonstrated the changes which may occur in the nitrogenous constituents of a phytoplankton population with time and environmental conditions. The model also demonstrates three phenomena which have been observed in field and laboratory experiments but which are not represented by the customary Monod model: (1) uptake rates may significantly exceed not growth rates, (2) high growth rates may be encountered at very low environmental nitrate concentrations, and (3) the ratio of internal nitrogen to population size may change significantly during a study period. It is suggested that the amount of nitorgen in storage may be used as an indicator of the physiological state of a monospecific population.Parameters for the one-compartment Monod model were estimated by customary methods form data generated by the three-compartment model. It was shown that difficulties encountered in estimating the yield coefficient and the decay coefficient may be attributed to the intracellular storage phenomenon. It was also demonstrated that the one-compartment Monod model was inadequate to accurately represent population growth in chemostat experiments when intracellular storage is a significant factor.
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  • 91
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    Biotechnology and Bioengineering 15 (1973), S. 403-412 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Immobilized invertase was prepared by ionically binding the enzyme to diethylaminoacetyl cellulose (DEAA-cellulose). DEAA-cellulose-invertase complex was quite stable to electrolyte in the range of pH 5-7. Bound invertase was less active than the native enzyme, and approximately 55-70% of the enzyme activity was lost on binding. The complex was stable for 9 days' continuous inversion in a column system at 30°C, but was rather unstable at 40°C. Heat stability and the effect of temperature on the reaction rate of the complex were almost identical with those of the native enzyme.
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  • 92
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    Biotechnology and Bioengineering 15 (1973), S. 441-445 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
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  • 93
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Many chemical and food processing wastes are deficient in nitrogen, and must therefore be supplemented with domestic sewage or ammonia to dispose of them by conventional biological treatment. A more economical treatment, especially of strong wastes, is possible by maintaining a semipure culture of nitrogen-fixing bacteria in a stirred aerated tank. When operated as a chemostat with 4 to 6 hr detention time, removal of 85% of the COD is possible in a single step without the need for clarifiers or digesters. A clarified effluent could also be produced by flotation or sedimentation of the flocculated bacteria. In that case there would be 99% removal of COD and a reduction in the amount of sludge by two-thirds over the conventional activated sludge process.
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  • 94
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    Biotechnology and Bioengineering 15 (1973), S. 419-439 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The synthesis of extracellular enzymes by microorganisms frequently occurs under genetic control. A simple two-parameter model is developed describing the degree of repression or induction in fermentation media.The case of substrate utilization by an extracellular enzyme was analyzed for a vegetable oil-lipase-yeast system. It is shown that fatty acids released by the lipase may accumulate in the early stage of growth and exert an influence on the limiting after which relatively little repression or induction takes place.Expressions are also derived for growth and extracellular enzyme synthesis in single-and multistage continuous cultures. When the cells grow on a directly available soluble substrate, the specific enzyme synthesis is maximal at low dilution rates in the case of repression and at high dilution rates in the case of induction. If the substrate is not directly available, a single continuous stirred tank reactor stage may not be sufficient for efficient substrate utilization; for fermentation processes where an insoluble has to be broken down before the cells can assimilate it, a plug flow type fermentor rather than a mixed chemostat may prove more satisfactory.
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  • 95
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    Biotechnology and Bioengineering 15 (1973) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 96
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    Biotechnology and Bioengineering 15 (1973), S. 455-466 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Papain was covalently coupled to ZrO2-coated porous glass by several different methods. These derivatives were characterized and their operational half-lives determined using casein substrate. Papain covalently coupled to the porous glass, previously converted to a carboxylic acid derivative, through amide linkage gave a 35 day operational half-life.
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  • 97
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    Biotechnology and Bioengineering 15 (1973), S. 27-45 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The oxygen uptake rate in mycelial pellets of Aspergillus niger was studied experimentally and theoretically. The specific rate of respiration of mycelial pellets was found to decrease significantly with increasing pellet size. The distribution of respiratory activity in the mycelial pellets was evaluated and the specific rate of respiration of disrupted mycelia showed adaptation to the concentration of oxygen in the medium. The decrease of the specific rate of respiration of the mycelial pellets could be estimated according to diameter, mycelial density, oxygen diffusivity, and adaptation to the concentration of oxygen. Good agreement was found between the theoretical analysis and the experimental data.
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  • 98
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    Biotechnology and Bioengineering 15 (1973), S. 117-127 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Various organic compounds were assessed as potential substrates for single cell protein production. Substrate evaluation was based on the costs associated with the substrate, oxygen, and heat yield coefficients: Ysub, Yo, and Ykcal, respectively. Yo, and Ykcal, were calculated from experimental values of Ysub, and from the elemental composition of bacterial cells. The dependence of the yield coefficients on the specific growth rate (μ) and maintenance coefficient (m) also was assessed. The analysis disclosed that m caused two- to threefold variations in the yield coefficients as μ was increased from 10% to 100% of μmax. The effect of different m values at constant specific growth rates also was determined. The value of m had a significant effect on the yield coefficients even at high specific growth rates. Assignment of cost factors to the yield coefficients provided an estimation of the impact m and μ on biomass production costs.
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  • 99
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    Biotechnology and Bioengineering 15 (1973), S. 181-196 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The solubilization of fish protein concentrate (FPC) by Bacillus subtilis protease (Monzyme) has been investigated. Conditions have been defined which eliminate the problems of microbial contamination and salt accumulation. A Kinetic treatment revealed that enzyme is adsorbed to the surface of the substrate, exposed to aqueous phase. The overall kinetics were described by a sequence of two first-order processes - an initial, fast reaction in which loosely bound polypeptide chains are cleaved from an insoluble protein particle, and a second, slower reaction in which more compacted core protein is digested.
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  • 100
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    Biotechnology and Bioengineering 15 (1973), S. 213-216 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Tab.
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