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  • 2015-2019
  • 1975-1979
  • 1970-1974  (665)
  • 1950-1954
  • 1915-1919
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  • 101
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 139 (1973), S. 377-388 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The Oberhautchen of scales from the dorsal, parietal, and ventral regions of Sceloporus occidentalis (Iguanidae), Gerrhonotus multicarinatus (Anguinidae), and Anniella pulchra (Anniellidae) were examined with a scanning electron microscope. At low magnification, all scales of S. occidentalis exhibit well-defined outlines of cells belonging to the Oberhautchen layer and the previously overlying clear layer. The dorsal and parietal cells of this species exhibit a minutely dentate Oberhautchen that forms tooth-like spinules 0.2 to 0.5 μ long and arranged in irregular rows. Minute pits 0.1 to 0.3 μ in diameter characterize the Oberhautchen of a ventral scale.Cell outlines are not evident on the scales of G. multicarinatus. The Oberhautchen of dorsal and parietal scales of this species is prominently laminated. Laminae are less prominent on scales of the lateral fold, and no intrinsic surface structure is evident on a ventral scale. In contrast, the fossorial anguinomorph Anniella pulchra exhibits Oberhautchen surfaces with practically no intrinsic microornamentation. However, what appear to be outlines of Oberhautchen cells are visible on the dorsal and ventral scales.These observations suggest that modifications of Oberhautchen microornamentation may have evolved to reduce friction with the substrate or other scales. The lack of pronounced microornamentation of the Oberhautchen on some body scales may indicate that a complex interdigitation between clear layer and Oberhautchen cells is not essential to the sloughing process.
    Materialart: Digitale Medien
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  • 102
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Stolonic growth has been compared among several genera of calyptoblastic (Campanularia flexuosa, C. calceolifera, Gonothyraea and Sertularia) and gymnoblastic (Pennaria, Bougainvillia, Eudendrium and Cordylophora) hydroids with respect to such features as the (1) complexity and uniformity of the tip movements, (2) constancy of growth cycle duration, (3) variability in growth among cycles, (4) growth rate, and (5) variability of retractions among cycles.The “growth cycle,” previously described in C. flexuosa, is the basis for elongation in all species observed. Its pattern is indistinguishable between the Campanularia species; however, at the generic level the tip movements show peculiarities which delineate each genus from all others. In addition, the movements in all calyptoblasts are uniform from cycle to cycle and comparatively simple, whereas those of the gymnoblasts are complicated by the variable appearance of one or more secondary forward thrusts between crests.A dichotomy is seen between the calyptoblasts and most gymnoblasts in other respects as well. Cycle time is very predictable and cycle-to-cycle variability in growth is relatively narrow in all calyptoblasts. However, in most gymnoblasts both features are much more loosely regulated: only Pennaria shows some degree of control to its timing mechanism, and only in Bougainvillia and Eudendrium does the uniformity of growth per cycle reach the calyptoblast level.On the premise that calyptoblasts are evolutionarily the more advanced group, simplicity and regularity of growth movements are concluded to be the evolved, and complexity and variability the primitive, conditions. On this basis the evolutionary relations among the four gymnoblasts, as deduced from their stolonic growth behavior alone, are consistent in many but not all respects with those interpreted from morphological considerations.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 103
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 139 (1973), S. 389-406 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In order to clarify the morphology of the circulatory system of amphioxus the blood vessels were investigated using modern techniques of light and electron microscopy.The pattern of circulation in amphioxus is forward ventrally and backwards dorsally. In addition, circulating corpuscles, usually associated with the blood of higher chordates, are absent.The circulatory system of amphioxus consists of well defined contractile vessels and vascular spaces or sinuses within a connective tissue matrix. The contractile vessels have a discontinuous endothelial lining resting on a basal lamina and are enclosed by a simple layer of contractile myoepithelial cells. Discontinuous endothelial linings occur throughout the vascular tree, including major and minor afferent and efferent vessels and blood sinuses. This is in contrast to higher animals where the endothelium forms a more or less continuous lining along the inner surface of the boundary layer.It is suggested that the endothelial cells of amphioxus, like the endothelial cells in capillaries of higher chordates, most likely play a role in the physiology of the circulatory system by removing residues of filtration from the basal lamina, thereby facilitating an exchange of materials to and from the surrounding tissues.
    Zusätzliches Material: 28 Ill.
    Materialart: Digitale Medien
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  • 104
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 139 (1973), S. 1-25 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The development of the polarity and bilateral asymmetry of the future adult zooid has been traced to their earliest morphological expression in the palleal bud of Botryllus. The account is based upon continued observation of living buds. The polarized antero-posterior and dorso-ventral axes are first expressed by the skewing of a symmetrical, hemispherical bud towards the anterior end of the parental bud. Identification of these axes is reinforced by the development of a loop-like blood circulation, the primary circulation, in the horizontal plane during the enlargement of the skewed hemisphere to form a stalked vesicle. Bilateral asymmetry is first expressed by the asymmetrical expansion of the vesicle stage. The right posterior corner of the vesicle expands further posteriorly and becomes more acute than the left posterior corner. This larger expansion persists throughout the development of the right atrial cavity, which finally expands across the mid-line to partially surround the gut. The bilateral asymmetry, expressed in the expanded vesicle, is reinforced by the development in sequence of a rounded gut rudiment and a pericardial rudiment in positions that would be expected from the asymmetry of the expanded vesicle. The first appearance of the gut rudiment occurs earlier than had been recognized previously. Conflicting accounts of the time and mode of formation of the pericardial rudiment have been clarified. The results of this study are discussed in the context of determination of bud territory, polarity and bilateral asymmetry.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
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  • 105
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 139 (1973), S. 27-45 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Four glands of the house sparrow, chicken and turkey were examined histologically and for their content of amylase. These were the external and intermediate mandibular glands, the maxillary gland and glandula anguli oris of the sparrow and the anterior and posterior mandibular, maxillary and anguli oris glands of the chicken and turkey. Amylase was determined by a starch substrate slide method and by biochemical assay. General morphology and mucopolysaccharide staining are described.All four glands of the sparrow demonstrated significant amylolytic activity by the assay. In the external mandibular and anguli oris glands this activity could be traced to mucous and seromucous cells of origin by means of the starch substrate slide procedure. None of the glands of the chicken or turkey displayed significant amylolytic activity.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 106
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 139 (1973), S. 67-78 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The distribution of monoamine (catecholamine and 5-hydroxytryptamine)-containing nerve cell bodies in the brain stem and hypothalmus of the frog (Rana temporaria) was investigated with the help of the histofluorescence technique of Falck and Hillarp ('62). At the level of the hypothalmus of this amphibian brain, catecholamine-containing nerve cell bodies are found mainly within three areas of the periventricular gray substance, namely the peroptic recess organ, the paraventricular organ and the lateral recess region. On the other hand, most of the 5-hydroxytryptamine (serotonin)-containing nerve cell bodies of the brain stem of Rana temporaria appear to be concentrated within the midbrain tegmentum. This huge mesencephalic nerve cell collection can be subdivided into medial and lateral groups. More caudally, at the level of the isthmic tegmentum, another group of 5-hydroxytryptamine-containing perikarya located close to the midline, within the so-called raphae region, is clearly outlined. The latter group of neurons extends caudally as far as the level of the medulla oblongata. In addition, a small group of catecholamine-containing nerve cell bodies is also found in the ventromedial portion of the rostral midbrain tegmentum, whereas a few other catecholamine type neurons are scattered throughout the lower brain stem of the frog and more especially near the ependymal wall of the fourth ventricle. As a whole, the 5-hydroxytryptamine-containing neuronal systems of the brain stem of Rana temporaria are much more elaborated than the catecholamine neuronal systems of the same structure.
    Materialart: Digitale Medien
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  • 107
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The guinea pig soleus muscle is a convenient model for the study of slow-twitch intermediate (STI) fiber ultrastructure because it is composed entirely of fibers of this class. Such fibers were compared with fast-twitch red (FTR) and fast-twitch white (FTW) fibers from the vastus lateralis muscle.FTW fibers are characterized by small, sparse mitochondria, a narrow Z line and, an extensive sarcoplasmic reticulum arranged primarily in longitudinal profiles at the A band and with numerous expansions at the I band. Abundant mitochondria with a dense matrix and subsarcolemmal and perinuclear aggregations are typical of FTR fibers. These fibers contain a plexus of sarcoplasmic reticulum at the A band and a less extensive network at the I band. The Z lines are wider (890 ± 74 Å) than those of FTW fibers (582 ± 62 Å). STI intermediate fibers are distinguished from other types by wide Z lines (1205 ± 58 Å), a faint M band, and a less extensive sarcoplasmic reticulum. Compared to FTR fibers, STI fiber mitochondria are usually smaller with less notable subsarcolemmal accumulations.FTW fibers have a more limited capillary supply, rarely contain lipid inclusions, and thus may be restricted to phasic activity. Extensive capillarity, mitochondrial and lipid context, and fast contraction times indicate possible phasic and tonic roles for FTR fibers. STI fibers, characterized by numerous lipid inclusions, extensive capillarity, relatively numerous mitochondria, but slow contraction-relaxation cycles, are morphologically suited for tonic muscle activity.
    Materialart: Digitale Medien
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  • 108
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 139 (1973), S. 79-103 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The haemocytes of Calpodes ethlius are described with the light and electron microscopes. Five fine structurally distinct types are distinguishable. However only three of these, the granular haemocytes, sphaerule cells and oenocytoids can be positively identified using a series of histochemical stains on smears and on thick sections of araldite-embedded material. The classification is based entirely on the structural features even though several suggestions concerning their function can be made from their fine structure. Intermediates having features of more than one cell type suggest developmental relationships.
    Materialart: Digitale Medien
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  • 109
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 139 (1973) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
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  • 110
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 139 (1973), S. 105-123 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Four hemocyte types have been identified in the late last larval instar of Galleria mellonella. Plasmatocytoids are round to spindle shaped cells, 10-20 μ long and 5-10 μ wide. The cytoplasm contains no distinguishing inclusions. Golgi complexes, rough endoplasmic reticulum and free ribosomes are abundant. Granular hemocytes are oval shaped cells, 10-20 μ long and 5-10 μ wide. The granules, their most characteristic feature, have a diameter of 0.2 μ, a microtubular sub-structure, and are made up of acidic mucosubstances. Lipid droplets may be present in these cells at some stage of development. These cells appear to be phagocytic. Spherule cells are oval shaped, 15-20 μ long and 5-10 μ wide. The spherules, approximately 2 μ in diameter, have a highly ordered substructure and are made up of acidic mucosubstances. Oenocytoids are the largest cells, 20 by 40 μ. The cytoplasm contains mostly free ribosomes and microtubules.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 111
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 139 (1973), S. 125-153 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The epineurium of the esophageal complex of the gastropod pulmonate Triodopsis divesta was examined by electron microscopy. The epineurium consists of two main regions: an inner dense fibrous region adjacent to the avascular neural tissue of the ganglion and an outer cellular region comprised of a variety of cell types embedded in a connective tissue matrix. The dense fibrous region contains smooth muscle cells and associated nerve processes and is invested on the neural side by thin processes of glial cells. The outer highly cellular region contains smooth muscle cells, nerve processes, wandering cells (amebocytes), globular cells, and myoepithelial cells comprising the walls of the vascular system. In addition, a cell type not previously identified in other gastropod epineuria is present. These cells resemble neurosecretory cells. The morphology and structural interrelationships of these various constituents are presented and the possible functions of individual cell types and the epineurium in general are discussed in relation to information available on other molluscs.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 112
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The muscles of the head, neck and thorax of the adult cabbage looper Trichoplusia ni are described for the first time. They are compared to those of Choristoneura fumiferana, Manduca sexta, Smerinthus geminatus, Antheraea polyphemus, Sphinx convolvuli, Crymodes devastator, and Danaus plexippus.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 113
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A precise sequence of four morphological stages of head regeneration in the planarian Dugesia tigrina has been determined by light and electron microscopy. Each stage is identified by a particular morphogenetic process: I, wound healing; II, blastema development; III, growth; IV, differentiation. A wound epidermis consisting of a thin, sheet-like layer of cells, rapidly forms from undamaged epidermal cells at the wound margin. The early blastema is comprised of neoblasts which mature into regeneration cells. The maturational changes include the appearance of a nucleolus, nuclear pores, and perinuclear dense aggregates of granulofibrillar material in these cells. These elements are not evident in the neoblasts of the younger blastema. No mitotic cells are encountered in the blastema or wound epidermis. Cytoplasmic expansion of the regeneration cells is correlated with the formation of numerous microtubules radiating from a juxtanuclear centrosphere. During differentiation of muscle cells, distended, granule-studded cisternae, having moderately fibrillar contents, are regularly disposed adjacent to small patches of myofilaments. Presumptive epidermal cells are recognized by prominent “islands” of finely fibrillar cytoplasm. These cytoplasmic zones persist for a time during definitive differentiation when Golgi bodies, vacuoles, mucous droplets, and rhabdites become evident. The newly formed epidermal cells become inserted among the cells of the wound epidermis. Thus, cells of both the blastema and of the wound epidermis contribute to the reconstituted epidermis.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 114
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 139 (1973), S. 211-225 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Five different kinds of sense organs have been identified on the antennal flagellum of males of Ptilocerembia sp: (1) tactile hairs, (2) thick-walled chemoreceptors, (3) chemoreceptors with thick walls and many pores, (4) thin-walled chemoreceptors and (5) campaniform sense organs. The third type has not been reported previously for other species of insects and combines the characteristics of typical thick-walled and thin-walled chemoreceptors. The campaniform sense organs are situated in sets of three, 120° apart, on the periphery of the distal end of nearly every subsegment. They lie at the transition zone where the thicker cuticle of the subsegment changes to the thin membrane between subsegments.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 115
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 140 (1973), S. 243-255 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The paddlefish (Polyodon spathula) is one of the most primitive and unique freshwater fishes of North America. It is adapted as a plankton filter-feeder. The wide mouth and greatly expansible pharyngeal cavity allows it to process a large quantity of water. Numerous setiform gillrakers, which operate against the flattened surfaces of the gill arches and opercula, are capable of filtering out small food particles. The abundance of taste buds and mucus secreting cells in the buccal cavity and pharynx probably aids in selecting and entangling the food. The first segment of the stomach is provided with peculiar, large longitudinal rods of fat which may help in selecting food from water by causing occlusion of the small lumen when the striated fibers of the muscularis contract. Teeth, unnecessary for microphagous fishes, are absent in adults.The digestive tube is one of the most complex present in fishes. It has two distinct divisions of the stomach and four distinct divisions of the intestine besides possessing a large caecum. Ciliated epithelial cells occur in many parts of the gut and may be an aid in moving or processing the small items of food.Besides the presence of cilia, other primitive features of the digestive tract include the lack of distinction between the esophagus and stomach, the presence of a spiral valve, and the presence of some of the diffuse pancreatic tissue within the wall of the gut.The numerous Peyer's patches in the wall of much of the intestine may be an immunological response to the heavy parasitic infestation.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 116
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973), S. 157-169 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The cranial glands of ten species of turtles were studied by the use of histochemistry applied to serial sections of whole heads. The majority were stenohaline species, but one brackish water form, Malaclemys, was included. The results show that all species have two major orbital glands, an anterior Harderian gland, and a posterior lachrymal gland. The latter is seromucous in all species except Malaclemys terrapin in which the gland shows little evidence or organic secretion. External and medial nasal glands are found in all species studied, and also are seromucous glands. With these reslts, combined with a review of the literature the following conclusions are made. The Harderian gland is by definition the orbital gland opening through the medial surface of the nictitating membrane at or near the anterior canthus. It is of constant occurrence, and histological appearance, probably serving the same function. However, despite much recent study this function remains unknown. The lachrymal gland is defined as the orbital gland which opens through the lateral surface of the nictitating membrane, or medial surface of the lower eyelid, at or near the posterior canthus. It is of variable occurrence, absent in many reptiles, and has a histological structure which is also variable. In the stenohaline species it is apparently involved in organic secretion, while in the brackish water Malaclemys it may be involved in salt secretion, as it is in Cheloniidae. The nasal glands in turtles are probably homologous with the nasal salt glands of lizards and birds, but they do not appear to subserve the same function. In all species of turtles studied the nasal glands are seromucous. They are perhaps involved in the maintenance of the epithelium of the olfactory cavity.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 117
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The dorsal proctodeal wall of the Coturnix contains a gland which is especially well-developed in the sexually active male and which secretes a foamy exudate. This gland has not been recorded in any other genus of birds and appears to be unique to members of the genus Coturnix. On the basis of its location in the adult we have named this gland the proctodeal gland (glandula proctodealis). Structure of the gland does not conform to any curently defined category of glands because it is an aggregate of individual glandular units each of which opens independently into the proctodeal cavity but with the entire structure enclosed by a connective tissue capsule. We have thus characterized it as an aggregate gland. Observations on the arrangement and composition of the fibrous capsule and its intimate relationship to the perimysium of M. sphincter cloacae indicate that release of the secretion probably results from contraction of the cloacal musculature. Preliminary data suggest that development of glandular tissue in the female may be a function of age rather than of androgen sensitivity which characterizes the male gland. It is concluded that the chemical nature of the glandular secretion and its function in the sexually active bird, as based on presently available information, remains unknown.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 118
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Wound healing in the integument of the sea cucumber, Thyone briareus, was studied for up to 50 days after inflicting wide excisional wounds and for 14 days after producing incisional wounds. Rapid re-epithelialization of the wound was effected by the migration of epidermal cells and pigment cells from the periphery of the wound margin. This occurred without apparent evidence of concomitant mitotic activity. Dermal wound healing was completed by the fourteenth day in the incision wounds but occurred very slowly in the broad excision wounds. Morula cells seem to be involved in both epidermal and dermal wound healing, although their precise role is unknown. In excisional wounds the integument was never completely restored to its normal appearance during 50 days of observation.
    Materialart: Digitale Medien
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  • 119
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973), S. 217-226 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The electron microscopy of the epiphysis cerebri of the antarctic seal Leptonychotes weddelli revealed a highly organized organ. The general cytological characteristics of the pinealocytes and the glial cells are described. The capillary blood vessels are the nonfenestrated type. The organ is richly innervated by mainly unmyelinated nerve fibers. Most of the axons end in the inner part of the organ, around vessels, some of them in relation with pinealocytes. The significance of the findings is discussed.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 120
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
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  • 121
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Cleavage and blastoderm formation in Coelopa frigida are extremely rapid developmental processes. In short (6-7 minutes) successive cell cycles, nuclei multiply and spread out through the egg. The movement seems to be aided by endoplasmic vesicles and cisternae which are in direct contact with the nuclear membrane. The first cells to separate from the egg plasmodium in early superficial cleavage stages are the pole cells.Precursor material from multivesicular bodies forms the pole cell membranes. The primary nuclei from the posterior pole region are removed from the blastoderm by the pole cell segregation. Blastoderm nuclei from the regions adjacent to the posterior pole migrate into the residual periplasm after pole cell segregation has been completed and constitute the blastoderm nuclei in that region of the egg. Nucleoli are not revealed during internal cleavage. They appear in pole cells shortly after their segregation. The generation time of the blastoderm nuclei increases after the twelfth cleavage. Concurrently, nucleoli form in the blastoderm nuclei and permanent cell membranes separate individual blastoderm cells. After blastoderm cells have been separated from each other, they remain in contact with the interior yolk sac by means of cytoplasmic canals. This contact is maintained at least during the early phases of blastokinesis. Observations on nuclear migration and rapid membrane formation are discussed as examples of protein assembly from subunits as an alternative to de novo protein synthesis in early stages of development.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 122
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Ovarian follicular histology of the lizard Anolis carolinensis was studied in relation to follicular size and rank. The structure of the Anolis follicular granulosa is similar to that described in other reptiles. Changes in the granulosa during follicular hypertrophy are also similar to those described in other species. Follicles of low rank in the linear size-gradation exhibited atresia.Counts were made of erythrocytes per millimeter of thecal tissue in crosssections of follicles of different size and rank. Follicles greater than 2.6 mm in diameter exhibited a marked increase in the number of thecal erythrocytes. Also, follicles of a similar diameter tended to possess a greater number of thecal erythrocytes the highter the rank in the linerar size-gradation. These observations support the hypothesis that follicular selection involves appropriation of blood and blood-borne hormones by larger follicles.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 123
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973), S. 257-267 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Some of the cytological and histochemical characteristics of hemocytes of Thyropygus poseidon were studied. Jone's system of classification of hemocytes was extended to millipede hemocytes. Seven classes were identified as prohemocytes, plasmatocytes, granular hemocytes, cytocytes, oenocytoids, spherule cells and adipohemocytes. Oenocytoids were rarely found. All cells except prohemocytes and oenocytoids sequestered oxidized products of catechol. Results of the histochemical tests for proteins also suggest that these cells sequester plasma proteins. Cytocytes do not bring about any visible coagulation similar to the hemocytes of some hemipteran insects. Granular hemocytes contain phenol-oxidase capable of oxidising tyrosine as well as catechol, similar to the hemocytes of crustaceans. In this respect millipede hemocytes differ from insect hemocytes. It is suggested that these cell types may represent distinct cell lines and may not represent transformation of one cell type to another.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 124
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973), S. 269-279 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Twenty-three stages in the embryonic development of the western painted turtle, Chrysemys picta bellii are described. The staging is based primarily on morphological changes, as well as age and size of the embryo.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 125
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Scanning and transmission electron microscopy were used to investigate the surface area and number per unit area of microvilli from jejunal villus epithelial cells in the rat, hamster and dog.The calculated mean microvillus surface area was 0.419 μ2, 0.573 μ2, 0.751 μ2 for the rat, hamster and dog respectively.The largest number of microvilli per square micron freeze dried villus surface was measured in the rat with a mean value of 65. Hamster and dog freeze dried specimens had lower mean values of 54 and 34 microvilli respectively.The total microvilli surface area in square micron per square micron villus surface was more closely related for the three species with values of 27.23 for the rat, 30.94 for the hamster and 25.53 for the dog.These data indicate an inverse relationship between the mean microvillus surface area and population density in the species studied. However, the total microvilli surface area per unit villus surface is relatively similar for the three species.The observed number of microvilli per unit villus surface was shown to vary depending upon the dehydration technique employed for preparation of scanning electron microscopic specimens. This variation probably reflects shrinkage artifact and should be considered in soft tissue studies involving the scanning electron microscope.
    Zusätzliches Material: 5 Tab.
    Materialart: Digitale Medien
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  • 126
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In Esox americanus and Esox niger (Esocidae) there are two types of surface pits, sensory and nonsensory. Both types of pits are morphologically very similar and are associated with modified (cardioid) scales. The pits are distinguished by the presence and absence respectively of neuromasts. Ultrastructure of the neuromasts indicates that they are basically similar to previously described neuromasts. However, the hair cells have crystalline-like deposits in the nuclear region. The nonsensory pit contains a small group of distinct epidermal cells, called central cells. These cells occupy a central position in the pit, similar to that of the neuromasts in the sensory pit. The central cells are unlike any cell types described for fishes, and on an ultrastructural basis no function can be ascribed to them and the significance of the nonsensory pit is unknown.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 127
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Esox americanus and Esox niger (esocidae) possess two types of surface pits, sensory and nonsensory. The pits are morphologically very similar and both are associated with modified (cardioid) scales. The pits are distinguished by neuromasts in the sensory and central cells in the nonsensory pit.Neuromasts and central cells are responsible for the formation and maintenance of respectively the pit and cardioid scale. This supports an extension of the epidermal co-participation hypothesis that epidermal cells control the form of dermal structures in addition to contributing to composition.The central cells are similar in structure to induced primordial cells of regenerating neuromasts.The development of primordial cells may be arrested and the cells maintained in a static condition during which time they still influence the dermal tissues and maintain a pit and cardioid scale. Essentially this represents the experimental conversion of a sensory pit into a nonsensory pit. This evidence is taken in support of the hypothesis that the nonsensory pit and central cells represent an aplasic condition of the lateral line system.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 128
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973), S. 293-305 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The gular gland of the bat Tadarida brasiliensis is a specialized sebaceous gland located in the skin of the suprasternal region of adult males. It consists of an aggregation of simple branched tubulo-acinar gland units, the number of which varies seasonally. Each acinus is composed of densely packed sebaceous cells at various stages of differentiation. Acinar basal cells and cells of the epithelium of the ducts can differentiate into sebaceous cells. Two main changes appear in the cytoplasm concurrent with the sebaceous transformation: the differentiation of cytoplasmic organelles and the deposition of lipid material. The appearance of a different type of mitochondrion and the development of large numbers of ribosomes and polyribosomes can be recognized in the cytoplasm at an early stage of differentiation. Concomitant with the deposition of significant numbers of lipid droplets, the cells develop abundant agranular endoplasmic reticulum occurring mainly as scattered tubular cisternae. These at times form whorls surrounding lipid droplets. At later stages, the cisternae of the agranular endoplasmic reticulum often occur in crystalline arrays between secretory oil droplets. The roles of the different cytoplasmic organelles, especially in relation to the production of sebum, are discussed.
    Materialart: Digitale Medien
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  • 129
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973), S. 345-357 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The mutant gene srn produces sireniform abnormalities in the mouse. The effects of this gene on normal prenatal development were examined histologically by retrograde analysis from day 10 through day 18 of gestation.The sireniformphenotype is characterized by the fusion of the hindlimbs and accompanying defects of the posterior appendicular skeleton. Visceral defects involve the urogenital system and the lower intestinal tract. A single umbilical artery arises from the dorsal aorta and controls the fetal circulatory pathway normally mediated by the lateral umbilical arteries. This artery is believed to have resulted from the fusion of the paired primitive umbilical arteries.It is suggested that the srn mutation causes a narrowing of the posterior amnion early in development. The resulting abnormal pressure causes a dorsal displacement of the hindgut, allowing fusion of the hindlimb buds. Abnormal structural relationships and pressure in the narrowed posteriior region disrupt normal urogenital and intestinal development and increase the proximity of the primitive umbilical arteries.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 130
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 131
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973), S. 359-381 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The retinofugal projections of the snake Thamnophis sirtalis were studied by the method of experimentally induced Wallerian degeneration stained by the Fink-Heimer method. The retinal ganglion cells project to all parts of the contralateral lateral geniculate complex, nucleus lentiformis mesencephali, nucleus geniculatus pretectalis, nucleus posterodorsalis, basal optic nucleus and superficial layers of the optic tectum. In addition, the retinofugal projections were observed terminating in portions of the ipsilateral lateral geniculate complex and nucleus posterodorsalis.Examination of the morphology of the retinal terminal areas stained for Nissl substance with cresyl violet led to the conclusion that these regions are well differentiated and should not be considered poorly developed when compared with other reptilian forms such as turtles.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
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  • 132
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973), S. 411-425 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The course of the statoblast formation in Pectinatella gelatinosa was divided into four stages and studied histologically and histochemically. The bottom of the cystigenous cup is a center of cystigenous cell differentiation and the peripheral zone of the inner cystigenous layer turns to the outer cystigenous layer as the cystigenous cup grows. The annulus is formed by migration and transformation of the outer cystigenous cells.During early stages, the yolk cells have an intensely pyroninophilic or RNA-rich cytoplasm. The cytoplasmic pyroninophilia then diminishes as the amount of yolk granules increases.Several kinds of yolk substances occur in the mature statoblast. During statoblast formation glycogen appears first, then glycoprotein and finally neutral unsaturated lipid.Acid phosphatase activity is associated with granular structures in the cytoplasm. In the cystigenous vesicle, acid phosphatase activity is low and confined to the apical extremity of the cell. Histochemically detectable alkaline phosphatase activity is not involved in the formation of the statoblast.
    Materialart: Digitale Medien
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  • 133
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973), S. 427-460 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The anatomy and physiology of feeding in miniature swine were studied, using gross dissection, electromyography, cinematography, and cineradiography.Small particles are preferred for ingestion, and large items are usually broken down outside of the oral cavity. The particles are initially picked up with the lower lip and then retrieved by the tongue; the tongue very rarely leaves the oral cavity. Geniohyoid, mylohyoid and digastric are the most active muscles during food collection.Mastication is fairly rapid (3 cycles/sec) and involves a transverse component which may be either medially or laterally directed. The direction of motion is generally reversed with every chew. Electromyography indicates that the transverse rotation is caused by a force couple consisting of protrusors (masseter, medial and lateral pterygoids) on one side and retrusors (zygomaticomandibularis and temporalis) on the other. The direction of the rotation is not necessarily related to the side containing the bolus. Mandibular depression is electromyographically biphasic. Concurrent tongue and hyoid movements complicate the interpretation of activity patterns in the oral floor.Both masticated food and liquid are stored between the tongue and the soft palate and epiglottis before being swallowed. Swallowing involves very strong activity in all of the hyoid and tongue muscles and very low activity in the adductors. Liquid is taken in by suction rather than lapping.Comparisons with other mammals are presented.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
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  • 134
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The wall of the gametolytic gland in Aplysia and Phyllaplysia consists of a muscular layer lined with an epithelium incorporating four distinct cell types, some of which show intense secretory activity. The cytoplasm of these cells, rich in RNA, has a peripheral layer of densely-packed mitochondria in association with a smooth endoplasmic reticulum. Lipid globules, perhaps resulting from absorption of lumen contents by microvilli, appear in the cytoplasm in the course of growth and reproductive activity. A basal band of fibrillar material appears to serve as a cytoplasmic skeleton. The elaboration of cell types, extensive areas of cytoplasmic RNA, and vigorous secretory activity suggest important roles for this organ such as development of food reserves, recycling of sexual materials of high physiological value, and interaction with the bag cells of the nervous system in coordinating ovulation with the availability of capacitated, exogenous sperm.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 135
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973), S. 383-394 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The predaceous neotropical characoid fish Ctenolucius has an essentially homodont dentition, the number of teeth increasing linearly with age. The basic manner of tooth replacement suggests that Ctenolucius is a primitive characoid. Tooth replacement continues throughout life and is similar to that of tetrapods, involving replacement waves which pass from the back to the front of the jaws. The waves containing the greatest number of teeth are found just anterior to the middle of the jaws. In the upper jaw the increase in the number of teeth is restricted to the anterior portion (premaxillary) whereas the number on the posterior part (maxillary) remains constant. In specimens measuring from 68-230 mm in standard length the posterior portion of the upper jaw doubles in length whereas the anterior portion triples. It is suggested that the area immediately anterior to the middle of the jaw, where replacement waves are longest, is where most of the increase in tooth numbers occurs.During growth of the teeth the absolute height is always greater than the absolute width as the shape changes. The final shape of the recurved conical teeth is determined only in the last stages of tooth formation when the main axis of growth abruptly changes.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 136
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973), S. 461-477 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Improved histological procedures have revealed in some detail the form and structure of auditory receptor organs in the frog. These organs, the papilla amphibiorum and papilla basilaris, are located in extensions of the saccular cavity, and lie in a path of vibratory fluid motion beginning at the columellar footplate and extending in a continuous circuit through the perilymph spaces and the round window back to the middle ear region.These organs exhibit great uniformity, and for the amphibian papilla there is a high degree of complexity in the tectorial structures that overlay the ciliated ends of the hair cells. In both papillae a “sensing membrane,” which is a derivative of the tectorial body, lies in the path of fluid flow and aids in the stimulation process.The mode of stimulation of the hair cells in the amphibian ear is peculiar, and in principle is the reverse of the familiar one of reptiles, birds, and mammals.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
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  • 137
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 141 (1973), S. 479-489 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: To determine the prism sheath configurations in human cuspal enamel 80 teeth were initially ground to produce flat surfaces through the following planes: a horizontal series at successively greater distances from the dentinoenamel junction and longitudinally through the center of the cusps. Individual teeth were suspended in an acid-alcohol solution (1 cm3 conc. HCl in 100 cm3 95% ethanol) at 37°C for seven to ten days. The treatment “softened” the enamel to a depth of approximately 1 mm. The teeth were embedded in Epon and sectioned at 0.5 to 10 μm with a diamond knife. Thick and thin ground sections for phase contrast microscopy and acid-etched ground sections for Nomarski differential interference microscopy were prepared through the same regions. In thicker longitudinal sections, the prisms in gnarled enamel formed a zig-zag pattern which was unlike the twisting pattern generally observed in ground sections. The thinnest transverse sections showed the sheath outlines to be dramatically different from those seen elsewhere in the enamel. Some prism sheaths were circular, others were in the form of spirals. What could be described as sheaths within sheaths were also seen. In the thinnest longitudinal sections the prisms were seen to be elongated and discontinuous. Sheath outlines in enamel adjacent to the central core of gnarled enamel were similar to those described elsewhere in the body of the enamel. Keyhole, modified keyhole patterns and arcade forms were the dominant sheath patterns. Other atypical sheath configurations were seen scattered throughout this region.
    Materialart: Digitale Medien
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  • 138
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The differentiation and degeneration of the cement gland in Xenopus laevis is described. The gland is first observed histologically at stage 19 (neural tube stage) as a packed group of apical ectoderm cells heavily laden with oocyte pigment granules, lying ventral to the cranial neural fold. By tailbud stage 35/36, the gland cells have increased in height and are approximately ten times taller than nonglandular apical ectoderm cells. The nuclei divide the gland cells into an apical region that is eosinophilic and contains oocyte pigment granules, and a basal region that contains clear droplets. The cells are decreasing in height by stage 40 (early tadpole) and begin to lose their pigment granules. Between stages 45 and 48, the pigment is extruded and the clear basal droplets diminish in number. From stage 48 to 49 the cells become vacuolated and the histotypic characteristics of the functional gland are lost. The gland is not vascularized, nor do phagocytic cells appear in its vicinity during any stage of its development. It remains bordered at its base by subjacent basal ectoderm during its entire life cycle of 10 to 12 days at room temperature.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 139
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 129-142 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 140
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 197-200 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 141
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973) 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 142
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 225-237 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 143
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 783-794 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 144
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 827-829 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 145
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 845-859 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 146
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 879-888 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 147
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1023-1037 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 148
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1123-1129 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 149
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1189-1192 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 150
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973) 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 151
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 85-91 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 152
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 143-161 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 153
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 201-206 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 154
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 933-949 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 155
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 981-992 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 156
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1011-1016 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 157
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1039-1044 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 158
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1081-1088 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 159
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1131-1145 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 160
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1159-1177 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 161
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 47-67 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 162
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 271-283 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 163
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 299-308 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 164
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 359-375 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 165
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 493-503 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 166
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 533-549 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 167
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 603-606 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 168
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 589-596 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 169
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 729-741 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 170
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 811-815 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 171
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973) 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 172
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 897-903 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 173
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 927-932 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 174
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 963-972 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 175
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1017-1017 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 176
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 177
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1075-1080 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 178
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1101-1121 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 179
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1179-1188 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 180
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1-12 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 181
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 93-115 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 182
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 163-179 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 183
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 207-211 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 184
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 693-705 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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).
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 185
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 677-692 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 186
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 707-728 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
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  • 187
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 817-818 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 188
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 821-825 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 6 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 189
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 861-877 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 190
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 191
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 192
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 1193-1197 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 193
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 331-358 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 194
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 403-412 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 195
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 441-445 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 196
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 413-418 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
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  • 197
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 419-439 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 198
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973) 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 199
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 455-466 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 200
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 15 (1973), S. 27-45 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: 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.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
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