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  • 2020-2023
  • 1985-1989
  • 1965-1969  (347)
  • 1968  (347)
  • Chemical Engineering  (257)
  • Biochemistry and Biotechnology  (78)
  • Kidney  (12)
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Years
  • 2020-2023
  • 1985-1989
  • 1965-1969  (347)
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  • 1
    ISSN: 1432-2013
    Keywords: Kidney ; Aldosterone ; Tubular Sodium Reabsorption ; Proximal Tubule ; Sodium Chloride Loading ; Niere ; Aldosteron ; tubuläre Natriumresorption ; proximaler Tubulus ; Natriumchloridbelastung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ratten erhielten 4 Wochen lang isotone Kochsalzlösung als Trinkflüssigkeit. Glomerulumfiltrat und Passagezeit von Lissamin-Grün im proximalen Tubulus blieben unverändert. Die spezifische Resorptionskapazität des Tubulusepithels — gemessen mit der „gespaltenen-Tropfen-Methode“ — nahm signifikant ab. Daraus ergab sich eine Verminderung der fraktionellen Natrium-und Wasserresorption im proximalen Tubulus von 51 auf 38% der gefilterten Menge. Die Na+-Ausscheidung stieg von 0,06 (Kontrollen) auf 1,25% der gefilterten Menge. Diese Veränderungen waren rückgängig zu machen durch Injektion von d-Aldosteron. Durch Bestimmung des TF/P-Inulin-Quotienten am Ende des proximalen Konvolutes wurden die Ergebnisse bestätigt. Es wird angenommen, daß die Resorptionshemmung im proximalen Tubulus bei chronischer Kochsalzbelastung durch verminderte Sekretion von Mineralocorticoiden bedingt und letzten Endes Ursache der vermehrten Na+-Ausscheidung ist. Ein Teil der proximalen Resorptionshemmung wird anscheinend in weiter distal gelegenen Nephron-Abschnitten kompensiert.
    Notes: Summary Rats were kept on isotonic saline as drinking fluid for a period of 4 weeks. Glomerular filtration rate and proximal transit time of Lissamine green remained unchanged. The intrinsic reabsorptive capacity of the proximal tubular epithelium—measured by the “shrinking-droplet-method”—decreased significantly. As a result, fractional proximal reabsorption of sodium and water decreased from 51 to 38 per cent of the filtered load. Sodium excretion rose from 0.06 (controls) to 1,25 per cent of the filtered load. These changes were reversible by injection of d-aldosterone. The results were confirmed by measuring the TF/P ratio of inulin at the end of the proximal convolution. The results indicate that in rats chronically loaded with salt, the inhibition of fractional proximal reabsorption is due to a decreased secretion of mineralocorticoids, and is the cause of the higher sodium excretion. Apparently, the decreased proximal reabsorption is partly compensated in more distal parts of the nephron.
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  • 2
    ISSN: 1432-2013
    Keywords: Kidney ; Concentration ; Dialysis ; Urea ; Electrolytes ; Niere ; Konzentrierung ; Dialyse ; Harnstoff ; Elektrolyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Um den Einfluß des Plasmaharnstoffspiegels auf die Konzentrierfähigkeit der Niere zu untersuchen, wird der Blutkreislauf von Ratten an eine Dialysiervorrichtung angeschlossen und der Harnstoffspiegel des Blutes für 3 Std durch Dialyse gegen eine harnstoffreie Spüllösung gesenkt. Gleichzeitig wird der Harnfluß der Tiere durch eine Regelanordnung konstant gehalten. Die Regelung wird dadurch erreicht, daß dem Blutkreislauf bei zu hohem Harnfluß automatisch Flüssigkeit entzogen und bei zu niedrigem Harnfluß Flüssigkeit zugeführt wird. Es wird gefunden, daß die Harnstoffkonzentrationen im Harn linear mit dem Plasmaharnstoffspiegel abfallen bzw. ansteigen. Die Summe der Elektrolytkonzentrationen fällt dagegen mit dem Plasmaharnstoffspiegel nur wenig ab. Falls ein völliger Harnstoffentzug möglich wäre, würde auch dann noch eine Konzentrierung der Elektrolyte auf mehr als doppelt isoton möglich sein. Die Ergebnisse der Untersuchung lassen sich am einfachsten mit der Annahme interpretieren, daß in der Niere der Ratte zwei unterschiedlich arbeitende Konzentrierungsmechanismen wirksam sind, von denen der eine im wesentlichen Elektrolyte, der andere im wesentlichen Harnstoff konzentriert. Der Konzentrierungsmechanismus für Elektrolyte könnte im äußeren Mark, der für Harnstoff im inneren Mark lokalisiert sein.
    Notes: Summary To investigate the influence of plasma urea levels on the concentrating power of the kidney, the blood circulation of rats was connected to a dialyser; with dialysis against a urea-free cleaning solution, the urea level of the blood was lowered for three hours. During this, the urine flow of the animals was kept constant by a regulating arrangement. This control was achieved by removing fluid from the blood circulation in the case of too high urine flow and by putting in fluid in the case of too low urine flow. It was found that the concentration of urea in the urine had a direct linear relationship with the plasma urea level. The total electrolyte concentration fell only slightly compared to the plasma urea level falls. If the urea could have been completely removed, high concentrating of the electrolyte, to more than double isotonic, would still have been possible. The simplest way to interpret the results of this research is by the hypothesis that two different concentrating mechanisms are at work in the rat kidney, the one essentially concentrating electrolytes, and the other principally urea. The concentrating mechanism for electrolytes could be localised in the outer medulla, and for urea in the inner medulla.
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  • 3
    ISSN: 1432-2013
    Keywords: Kidney ; Concentration ; Infusion ; Urea ; Electrolytes ; Niere ; Konzentrierung ; Infusion ; Harnstoff ; Elektrolyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Um die gegenseitige Beeinflussung von Harnstoff und NaCl bei der Bildung eines konzentrierten Harns zu untersuchen, werden Ratten 2 Tage lang NaCl-Lösungen mit wechselndem Harnstoffgehalt infundiert. Sodann werden der Harn sowie das Gewebe der Nierenrinde, des äußeren Marks und des inneren Marks auf ihren Gehalt an Kalium, Natrium und Harnstoff analysiert. Es wird gefunden, daß die Konzentrierfähigkeit der Rattenniere unter diesen Versuchsbedingungen für NaCl bei gleichzeitiger Zufuhr von Harnstoff geringer wird. In der Niere steigen NaCl und Harnstoffkonzentrationen unter allen Infusionsbedingungen von der Nierenrinde zur Nierenpapille hin an. Bei Infusion reiner NaCl-Lösungen entsprechen die NaCl- und Harnstoffkonzentrationen im Harn denen in der Papille. Bei Infusion von harnstoffhaltigen NaCl-Lösungen sind im Harn die NaCl-Konzentrationen höher und die Harnstoffkonzentrationen niedriger als im Papillengewebe. Diese Ergebnisse schließen aus, daß die hohen Harnstoffkonzentrationen im Nierenmarkgewebe durch einfache Diffusion des Harnstoffes aus den Sammelrohren in das Nierenmarkgewebe zustande kommen. Es wird die Möglichkeit diskutiert, daß die Harnstoffkonzentrierung unter den hier wiedergegebenen Versuchsbedingungen durch Gegenstromdiffusion in dem Vasa recta-System verursacht wird. Der Konzentriereffekt hierfür könnte durch einen Wasserfluß aufgrund osmotischer Kräfte von dem Blutgefäßsystem in die Henleschen Schleifen zustande kommen, wenn der Harn in den Henleschen Schleifen durch Aufnahme von NaCl, das aus den Sammelrohren stammt, hyperton wird.
    Notes: Summary To investigate the mutual interdependence of urea and sodium in producing concentrated urine, solutions of different concentrations of sodium and urea were infused into the stomach of rats. After two days' infusion, the urine and tissues from the different zones of the kidneys were analysed for sodium, potassium and urea content. It was found that the efficiency of the rat kidney in producing urine with high sodium content was diminished if urea was infused together with the sodium chloride. Under all conditions sodium and urea concentrations increased from the cortex to the papilla of the kidneys. When pure sodium chloride solutions were infused, sodium and urea concentrations in the urine were nearly equal to the corresponding concentrations in the papilla. Infusion of solutions containing NaCl and urea caused production of urine with a higher sodium concentration and lower urea concentration than in the papilla. These results show that the high concentration of urea in the medulla of the kidney does not arise by passives diffusion of urea from the collecting ducts into the medullary tissue. The possibility that the concentration of urea in the inner medulla is produced by counter current diffusion of urea in the vasa recta is discussed. The concentration effect necessary for this counter current multiplication could be created by an osmotic flow of water from the vasa recta into loops of Henle, if the urine in the loops becomes hypertonic by taking up sodium chloride from the collecting ducts.
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  • 4
    ISSN: 1432-2013
    Keywords: Tubules ; Kidney ; Intraluminal Oil Injection ; Ultrastructure of Kidney ; Proximales Tubuluskonvolut ; Rattenniere ; intraluminale Ölinjektion ; Ultrastruktur der Niere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Light- and electronmicroscopic evaluation of proximal convolutions of the rat kidney were made following injection with either mineral oil or castor oil. The following observations were made: 1. Injection of mineral oil does not result in a complete blockade of the tubular lumen and leads to morphological lesions of epithelial cells. 2. Injection of the more viscous castor oil, in contrast, leads to a dilatation of the tubular lumen and a compression of the brush border of proximal tubular cells. Thus a better blockade of longitudinal flow is achieved. A toxic effect of castor oil on the tubular epithelium could not be detected. Mechanical lesions, similar to those observed after mineral oil injection, were less frequent. They consisted in a penetration of oil into the cells, perhaps as consequence of the tubular dilatation. 3. In oil-injected proximal tubular segments the following cytologic phenomena were observed: a) a cessation of the normal pinocytosis, which is induced in the presence of tubular fluid, b) simultaneously the “large resorption vacuoles” disappear, indicating that they originate from confluence of pinocytotic vesicles, c) in dilated tubules protein resorption vacuoles are found to have ruptured towards the tubular lumen suggesting a high hydrostatic pressure within the vacuoles.
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  • 5
    ISSN: 1432-2013
    Keywords: Kidney ; Experimental Hypertension ; Tubular Sodium Reabsorption ; Tubular Water Reabsorption ; Henle's Loop ; Niere ; experimenteller Hochdruck ; tubuläre Natriumresorption ; tubuläre Wasserresorption ; Henlesche Schleife
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 4 Wochen nach Klammerung einer Nierenarterie war der Perfusionsdruck der geklammerten Niere normal, während der arterielle Mitteldruck auf 188 mm Hg angestiegen war. Die Ausscheidung von Natrium und Wasser im Harn der geklammerten Niere war normal, im Harn der ungeklammerten Niere erheblich höher als normal. Glomerulumfiltrat (pro g Niere), intratubulärer Druck, Tubulusweite, Passagezeit von Lissamingrün und die fraktionelle Resorption von Natrium und Wasser waren im proximalen Tubulus sowohl in der geklammerten wie in der ungeklammerten Niere normal. In der ungeklammerten Niere war die Passagezeit durch die Henlesche Schleife stark verkürzt und die Resorption von Natrium und Wasser in der Schleife erheblich vermindert. Diese Veränderungen — obwohl zum Teil kompensiert durch vermehrte Resorption im distalen Tubulus und im Sammelrohr — sind verantwortlich für die höhere Wasser- und Natriumausscheidung der ungeklammerten Niere. Die Ursache ist wahrscheinlich eine stärkere Durchblutung des Nierenmarkes. Im Nephron der geklammerten Niere war die fraktionelle Natrium- und Wasserresorption nicht signifikant von normalen Werten verschieden mit der Ausnahme einer niedrigeren Natriumresorption im distalen Tubulus und einer höheren Natriumresorption im Sammelrohr. Der Natrium-Transport im distalen Tubulus ist anscheinend gestört; TF/P−Na+ betrug im Mittel 0,6 bis zum Ende des distalen Tubulus. Die Ergebnisse können die unterschiedliche Harnausscheidung erklären, die beim Hypertoniker mit einseitiger Nierenarterienstenose beobachtet wird (Howard-Test).
    Notes: Summary Four weeks after clamping one renal artery, the perfusion pressure of the clamped kidney was normal whereas the mean arterial pressure had increased to 188 mm Hg. Urinary excretion of sodium and water of the clamped kidney had not changed while that of the untouched kidney increased considerably. Glomerular filtration rate (per g kidney), intratubular pressure, tubular diameter, transit time of Lissamine green and fractional sodium and water reabsorption of the proximal tubule were normal in both the clamped and the untouched kidney. In the untouched kidney, the transit time through Henle's loop was shortened and the sodium and water reabsorption in it was significantly reduced. These changes, although partly compensated by higher reabsorption in the distal tubule and collecting duct, are responsible for the increased sodium and water excretion of the untouched kidney. They are probably due to an increased medullary blood flow. In the clamped kidney, fractional sodium and water reabsorption of the whole nephron did not differ significantly from normal values. However, sodium reabsorption was lower in the distal tubule and higher in the collecting duct. Sodium transport in the distal tubule seemed to be impaired; throughout its length sodium TF/P ratio averaged 0.6. These results may explain the different urinary excretion found in human hypertension following unilateral renal artery stenosis (Howard-Test).
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  • 6
    ISSN: 1432-2013
    Keywords: Kidney ; Fluxes ; Osmotic Gradients ; Niere ; Flüssigkeits-Substanzbewegungen ; osmotische Gradienten
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Durch artifizielle osmotische Druckdifferenzen von 150 mOsmol/l zwischen Lumen- und Blutseite der Tubulusepithelien von Rana ridibunda wird Flüssigkeit im Richtungssinne der Reabsorption oder — in geringerem Maße — der Sekretion längs des osmotischen Gradienten bewegt. Na+ wird in jedem Fall „trocken” reabsorbiert. Bei mit Furosemid blockiertem aktiven Na+-Transport läuft isoton Flüssigkeit längs des osmotischen Gradienten aus dem Tubuluslumen in das blutseitige Medium. Bei umgekehrt gerichtetem Gradienten wird das Filtrat so verändert, als ob es durch Einstrom reinen Wassers verdünnt würde. Die Tubulusepithelien verhalten sich so, als besäßen sie — im Zustand des blockierten aktiven Na+-Transportes — ein „Rückschlagventil” für Na+. Wenn der osmotische Gradient so gerichtet ist, daß Wasser oder Flüssigkeit aus dem Lumen in das blutseitige Medium läuft, dann kommt es bei umgekehrt gerichtetem Na+-Konzentrationsgradienten nicht zum Einstrom von Na+ in das Tubuluslumen. Die Na+-Harnkonzentration sinkt beträchtlich unter die des Perfusates, was als Ausdruck einer Na+-Reabsorption gegen den Konzentrationsgradienten gedeutet wird. Bei Blockierung des Na+-Transportes durch Furosemid kommt es wiederum zum Einstrom reinen Wassers in die Tubuluslumina. Die Versuche mit durch Furosemid blockiertem Na+-Transportmechanismus sind beweisend, daß die Tubuli für Na+ im Richtungssinne der Sekretion impermeabel sind. Die „Verdünnung” des Tubulusinhaltes durch einen osmotischen Gradienten, der Wasser in die Tubuli hineinlaufen läßt, kommt also nicht durch ein Überwiegen der Reabsorption über die „Sekretion” zustande. Wird statt des leicht penetrierenden Na-Chlorids das schwer penetrierende Natriumcyclohexansulfamat angeboten, dann wird absolut gegenüber den Versuchen mit Na-Chlorid weniger Na+ transportiert. Im übrigen zeigen die Nieren jedoch das gleiche Verhalten wie bei Angebot von Na-Chlorid.
    Notes: Summary Osmotic gradients of 150 mosmol/l between intratubular fluid and blood in the kidney of Rana ridibunda induce a fluid movement down the osmotic gradient which is stronger into the tubule than out of it. In either case Na+ is reabsorbed “dry”. If the active Na+-transport is blocked by Furosemid an osmotically downhill movement of isotonic fluid out of the tubule obtains. Reversal of the osmotic gradient induces a reversal of flow but the inward moving fluid is diluted. The tubular cells seem to inhibit the backwash of Na+. If the osmotic gradient induces an outflow of fluid out of the tubule no influx of Na+ occurs even in the presence of a concentration gradient for Na+ in the opposite direction. The Na+-concentration in the urine falls considerably below that of the perfusion fluid. This finding indicates Na+-reabsorption against a concentration gradient. Upon blocking of the Na+-transport by Furosemid water enters the tubules. The results of the experiments in which the Na+-transport was blocked by Furosemid prove that the tubules are impermeable for Na+ in the direction of secretion. The “dilution” of the tubular fluid as a result of an osmotic gradient which induces an influx of water isnot due to a reabsorption outbalancing “secretion”. If instead of the easily penetrating NaCl the slowly penetrating Na+-cyclohexanesulphamate is used, less Na+ is transported. However, in every other respect the results obtained are similar to those described above.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 304 (1968), S. 336-350 
    ISSN: 1432-2013
    Keywords: Kidney ; Experimental Hypertension ; Distal Tubular Sodium Reabsorption ; Distal Osmolality ; Tubular Potassium Secretion ; Niere ; experimenteller Hochdruck ; distale Natrium resorption ; distale Osmolalität ; tubuläre Kaliumsekretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Vier Wochen nach Klammerung einer Nierenarterie wurde die Funktion des distalen Tubulus untersucht. In der ungeklammerten, unter dem hohen Blutdruck stehenden Niere blieb die Tubulusflüssigkeit bis 90% distaler Tubuluslänge hypoton. Dies wird auf eine erhöhten Flüssigkeitseinstrom aus der Henleschen Schleife zurückgeführt; eine verminderte Wasserpermeabilität des distalen Tubulus konnte nicht nachgewiesen werden. In der geklammerten Niere war mit Ausnahme des frühdistalen Abschnittes die Natriumkonzentration on jeder Stelle des distalen Konvolutes signifikant höher als in der ungeklammerten Niere und in Kontrollnieren. Auch fehlte im distalen Tubulus der geklammerten Niere eine Nettokaliumsekretion. die distale Gleichgewichtskonzentration für Natrium war auf der geklammerten Seite erhöht, auf der ungeklammerten Seite normal. Der isotone Natriumausstrom (Methode des gespaltenen Tropfens) war in der geklammerten Niere vermindert, in der ungeklammerten Niere erhöht. Die frühdistale Harnstoffkonzentration war in der ungeklammerten Niere gegenüber der geklammerten Niere und Nieren von Kontrollratten erniedrigt. Spätdistal war TF/P-Harnstoff in beiden Nieren gleich. Beide Nieren hatten ein normales Glomerulumfiltrat und normale tubuläre Passagezeiten mit Ausnahme einer verkürzten Schleifenzeit in der ungeklammerten Niere. Die Befunde werden dahingehend interpretiert, daß der aktive Natriumtransport im distalen Tubulus der beiden Nieren voneinander verschieden ist, möglicherweise infolge des unterschiedlichen Reningehaltes der beiden Nieren.
    Notes: Summary Four weeks after constricting one renal artery distal tubular function was studied using the micropuncture technique. In the untouched kidney tubular fluid remained hypotonic up to 90% distal tubular length. We believe this to be the result of the high inflow of tubular fluid from Henle's loop. A reduced permeability for water could not be demonstrated. Except for the early part of the distal tubule there was a marked increase in sodium concentration in the clamped kidney as compared to values obtained in the untouched one and in kindneys of control animals. In addition no potassium secretion could be observed in the clamped kidney. The distal steadystate concentration for sodium was increased in the clamped kidney and normal in the untouched one. Reabsorptive half-time, measured by the split droplet technique, was prolonged in the clamped kidney and shortened in the untouched one. Early distal urea concentration was lower in the untouched kidney than in the clamped one and in control kidneys, while at the end of the distal tubule urea concentrations did not differ significantly. Both kidneys had normal glomerular filtration rates and proximal tubular transit times, whereas a shortened transit time through Henle's loop of the untouched kidney was found. The results indicate that active sodium transport in the distal tubule of the clamped kidney differs from that of the untouched one, possibly due to the different renin concentration in both kidneys.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 305 (1968), S. 96-104 
    ISSN: 1432-2013
    Keywords: Blood Circulation Time ; Kidney ; Plasma ; Radioautography ; Radioisotope Dilution Technique ; Regional Blood Flow ; Mittlere Kreislaufzeit ; Niere ; Plasma ; Autoradiographie ; Isotopenverdünnungstechnik ; Regionale Nierendurchblutung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary At different times after injection into the renal artery of131I-albumin, the distribution of the tracer in kidneys of the rabbit and the dog was illustrated by a series of autoradiograms. In order to determine the mean circulation time for albumin in the kidney, the radioactivity over the kidney was simultaneously registered by external monitoring. A short mean circulation time was measured for albumin (plasma) passing cortex, and a longer one for that fraction of the albumin that passed through medulla, papillae, and capsule. The investigation rendered probable that the mean circulation time for blood through the kidney determined by the external technique applies to blood passing cortex. The circulation times for blood through medulla, papillae, and capsule are not included in the calculation of the mean circulation time.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 23 (1968), S. 245-249 
    ISSN: 1432-0738
    Keywords: Bone ; Strontium poisoning ; Parathormone ; Kidney ; Knochen ; Strontiumvergiftung ; Parathormon ; Niere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Restitution des strontiumgeschädigten Skelets wachsender Sprague Dawley Ratten ist von einem Anstieg der dialysablen Strontium- und Calciumfraktion des Serums begleitet. Die Ergebnisse legen eine Beeinflussung der renalen Manipulation von Kationen bei Knochenschädigungen durch Fremdmetalle nahe.
    Notes: Summary Restitution of skeletal damage caused by strontium in growing Sprague Dawley rats is accompanied by an increase in the dialysable serum fractions of strontium and calcium. The results suggest that the renal manipulation of cations is influenced in bone lesions caused by foreign metals.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Clinical and experimental medicine 145 (1968), S. 270-277 
    ISSN: 1591-9528
    Keywords: Aldosterone ; Kidney ; Stop flow dog ; Aldosteron ; Niere ; Stop flow-Hund
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Mit Stop flow-Versuchen an Hunden konnten wir nach Infusion von 1,2-3H-18-Aldosteronglucuronid im Gegensatz zur Infusion von freiem 1,2-3H-Aldosteron keine proximale Sekretion von 1,2-3H-18-Aldosteronglucuronid nachweisen. Daraus kann geschlossen werden, daß in Hundenieren die proximalen Tubuluszellen wohl 18-Aldosteronglucuronid aus Aldosteron bilden und an das Tubuluslumen abgeben, während im Nierenarterienblut vorhandenes 18-Aldosteronglucuronid nur glomerulär filtriert und ausgeschieden wird.
    Notes: Summary In stop flow experiments during infusion of 1,2-3H-18-aldosterone glucuronide there was no proximal tubular secretion of this metabolite in contrary to experiments during infusion of 1,2-3H-aldosterone. The discrepancy must be explained by formation of 1,2-3H-aldosterone glucuronide out of3H-aldosterone in proximal tubular cells, while the 1,2-3H-18-aldosterone glucuronide in the plasma of the renal artery blood is only filtered in the glomerulum.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Clinical and experimental medicine 146 (1968), S. 336-345 
    ISSN: 1591-9528
    Keywords: Aldosterone ; Kidney ; Man ; Aldosteron ; Niere ; Mensch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Auf Grund eines Vergleiches der Verhältnisse von 1,2-3HTetrahydroaldosteronglucuronid zu 1,2-3H-18-Aldosteronglucuronid im Plasma von drei Normalpersonen und zwei nephrektomierten Patienten nach einer Injektion von 1,2-3H-Aldosteron haben wir folgende Schlüsse in Betracht gezogen: 1. Das im Blutplasma vorhandene 1,2-3H-18-Aldosteronglucuronid wird nur glomerular filtriert. 2. Die renale Clearance von 18-Aldosteronglucuronid, die etwa das Fünffache der Inulinclearance beträgt [13, 15], mu\ zu vier Fünfteln auf Bildung von 18-Aldosteronglucuronid durch die proximalen [15] Tubuluszellen zurückgeführt werden. 3. Das Ausma\ der renalen Bildung von 18-Aldosteronglucuronid liegt in einer Grö\enordnung von 80% der Gesamtmenge 18-Aldosteronglucuronid im 24 StdUrin.
    Notes: Summary After an intravenous injection of 1,2-3H-aldosterone the ratios of 1,23H-tetrahydroaldosterone glucuronide to 1,2-3H-aldosterone glucuronide in the blood plasma of three normal and two nephrectomized persons were compared. In the three normal persons the ratios were of the same magnitude as in the two nephrectomized persons. On the basis of glomerular filtration of tetrahydroaldosterone glucuronide, as previously demonstrated by renal clearance studies in man [13, 15] and stop flow experiments in dogs [6], we made the following deductions: 1. 18aldosterone glucuronide in blood plasma is only filtered in the glomerulum. 2. The renal clearance of 18-aldosterone glucuronide, as investigated during aldosterone infusion in man [13, 15], therefore must be explained by glomerular filtration of only one fifth and by formation of four fifth of 18-aldosterone glucuronide by proximal [15] tubular cells. 3. This means that about 80% of 18-aldosterone glucuronide excreted in urine is formed by the kidneys.
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  • 12
    ISSN: 1591-9528
    Keywords: Plasma FFA composition ; Individual FFA extraction in heart ; Skeletal muscle ; Kidney ; Plasma-FFS-Zusammensetzung ; Extraktion der Einzel-FFS in Herz ; Skeletmuskel ; Niere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei narkotisierten Hunden wurden die arteriovenösen Differenzen der gesamten und der einzelnen freien Fettsäuren (FFS) am Herzen, am elektrisch stimulierten Skeletmuskel (M. gastrocnemius) und an der Niere bei verschieden hoher arterieller FFS-Konzentration untersucht. Die Konzentration der gesamten FFS wurde titrimetrisch, ihre Zusammensetzung wurde gaschromatographisch bestimmt. Bei einer Steigerung der FFS-Konzentration durch Noradrenalininfusionen stiegen die Anteile der öl- und der Palmitinsäure an, und die Anteile der Stearin- und der Linolsäure sanken ab. Bei einer Senkung der FFS-Konzentration durch Glucoseinfusionen nahmen die Anteile der öl- und der Palmitoleinsäure ab, und die Anteile der Palmitin- und der Stearinsäure nahmen zu. Unter Kontrollbedingungen entfielen am Herzen 44% der gesamten FFS-Extraktion auf die öl- und 24% auf die Palmitinsäure, am Skeletmuskel entfielen 43% auf die öl- und 29% auf die Palmitinsäure. Bei einer Steigerung der arteriellen FFS-Konzentration durch Noradrenalin extrahierten Herz- und Skeletmuskel nur noch öl-, Palmitin- und Palmitoleinsäure. Gleichzeitig wurde im Herz Stearin- und Linolsäure und im Skeletmuskel Stearinsäure produziert. In der Niere entfielen unter Kontrollbedingungen je 40% der Gesamt-FFS-Extraktion auf die Palmitin- und die ölsäure. Es wird gefolgert, daß die öl-, die Palmitin- und die Palmitoleinsäure gegenüber den anderen FFS bevorzugt als Energiequellen benutzt werden, weil bei gleicher arterieller Konzentration höhere Extraktionen für diese drei FFS gemessen wurden. Noradrenalin bewirkt, wahrscheinlich durch Aktivierung von Lipase, im Herzen und im arbeitenden Skeletmuskel einen Abbau von gespeicherten oder im Plasma transportierten Triglyceriden.
    Notes: Summary The arteriovenous differences of total and individual free fatty acids (FFA) have been determined in the myocardium, in the electrically stimulated skeletal muscle (gastrocnemius) and in the kidney of closed chest anesthetized dogs. The concentration of total FFA was determined by titration, their composition was determined by gaschromatography. When the arterial concentration of total FFA was increased by norepinephrine infusions the percentage of olic and of palmitic acid increased and the percentage of stearic and linolic acid decreased. When the concentration of total FFA was decreased by glucose infusions the percentage of olic and palmitolic acid decreased and the percentage of palmitic and stearic acid increased. Under control conditions in the myocardium 44% of the total FFA extraction were related to olic and 24% to palmitic acid and in the skeletal muscle 43% were related to olic and 29% to palmitic acid. During norepinephrine induced increases of arterial FFA concentration myocardium and skeletal muscle extracted only olic, palmitic and palmitolic acid. At the same time in the myocardium stearic and linolic acid and in the skeletal muscle stearic acid was produced. In the kidney under control conditions 40% of the total FFA extraction were related to palmitic and 40% to olic acid. Since the extraction of olic, palmitic and palmitolic acid was higher than the extraction of other FFA at comparable arterial concentrations, it is concluded, that these three FFA are used in preference to other FFA as energy sources. Norepinephrine causes, probably via activation of lipase, in the myocardium and in the working skeletal muscle a breakdown of stored or in plasma transported triglycerides.
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  • 13
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    Biotechnology and Bioengineering 10 (1968), S. 205-232 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A generalized logistic equation is proposed for the mathematical representation of batch culture kinetic data. Properties of the equation are discussed. A computer program is used to fit the generalized equation to both artificial and actual batch culture data. The equation is shown to be capable of fitting data exhibiting lag, exponential, deceleration, stationary, and death phases, as well as diauxic growth. The fitted equation is useful for differentiation, interpolation, and other manipulations of the data, and it is a convenient means of data storage.
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  • 14
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    Biotechnology and Bioengineering 10 (1968), S. 252-254 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 15
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    Biotechnology and Bioengineering 10 (1968), S. 277-289 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Micrococcus sodonensis KY 3765 and Arthrobacter citreus KY 3155 were found capable of accumulating IMP in media supplemented with hypoxanthine as a precursor. High concentrations of phosphate and magnesium salts were required for high yields of IMP. Manganese deficiency in the media was also essential. Excessive Mn2+ effects were also seen in the IMP fermentation carried out with an adenineless mutant, of Cornynebacterium glutamicum. In M. sodonensis, R5P-like substances, 5-phosphoribose pyrophosphokinase and IMP pyrophosphorylase, were leaked out, of the cells grown in suboptimal Mn2+ levels. This excretion was inhibited by high levels of Mn2+. Such a phenomenon was not noted in A. citreus. An adenineless mutant (KY 7208) of Brevibacterium ammoniagenes was found to accumulate an appreciable amount of IMP. The chemical changes in this fermentation showed that, hypoxanthine was first produced de novo, excreted, and then reconverted into IMP by a salvage pathway. When hypoxanthine was added to 7208 culture, IMP yield was increased appreciably. In fact exogenous 14C-hypoxanthine was incorporated into 14C-IMP. Subsequent experiments showed that indeed Br. ammoniagenes ATCC 6872, a parent culture of KY 7208, was able to produce IMP, GMP, and AMP, in good yield from hypoxanthine, guanine, and adenine, respectively.
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  • 16
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    Biotechnology and Bioengineering 10 (1968), S. 331-358 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mechanism of oxygen transfer through a pure culture floc of Zoogloea ramigera I-16M has been described quantitatively. Oxygen uptake rates for both blended and nonblended floc particles indicated that, at a certain dissolved oxygen concentration, diffusion of oxygen through the floc matrix was the mechanism controlling the rate of oxygen utilization by the floc. This mechanism was quantitatively described by determining the oxygen diffusivity values for the floc. The diffusional distances of the floc particles along with the oxygen utilization rates of the floc were measured on floc grown under various conditions. Anoxic core equations were then used to calculate the oxygen diffusivity values for each experiment. These diffusivity values were then used to estimate the oxygen concentrations necessary in activated sludge plants.
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  • 17
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    Biotechnology and Bioengineering 10 (1968) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 18
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    Biotechnology and Bioengineering 10 (1968), S. 445-455 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Many hyphomyceteous fungi have been found to produce closely related toxic metabolites which form the class of compounds called scirpenes. The structures of those compounds are reviewed and current studies on their biological activity and possible implication in moldy corn poisoning are discussed.
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  • 19
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    Biotechnology and Bioengineering 10 (1968) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 20
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    Biotechnology and Bioengineering 10 (1968), S. 787-800 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Growth of Saccharomyces cerevisiae LBG H 1022 on ethanol under transient-state conditions was studied. As a cultivation device, an aerated Chemap fermentor combined with continuously working gas analyzers for oxygen and carbon dioxide was used. Yeast cell dry matter, substrate concentration, specific oxygen uptake, specific carbon dioxide release, and respiration quotient were measured during the different transient states. Depending on which range of the dilution rate the initial steady state was found, we obtain different responses to the shift experiment. For the lower range, up to D = 0.07, we deal with damped oscillations ranging above and below the steady-state values. For the higher specific growth rates, the rate of damping is strongly enhanced and the shape of the curves becomes an asymptotic approach to the final steady states.
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  • 21
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    Biotechnology and Bioengineering 10 (1968), S. 891-894 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 22
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    Biotechnology and Bioengineering 10 (1968), S. 83-88 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model based on the Einstein law of photochemical equivalence is proposed to describe the batch growth of unicellular algae. The model was applied in an integrated form to cell concentration versus growth time data taken over an extended range of cell concentrations which include both the regions of “exponential” and “linear” growth. It is shown that a certain function of cell concentration contained in the integrated form of the model is linearly dependent on the growth time over both the “exponential” and “linear” growth regions.
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  • 23
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    Biotechnology and Bioengineering 10 (1968) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 24
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    Biotechnology and Bioengineering 10 (1968), S. 159-176 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Growth of Saccharomyces cerevisiae LBG H 1022 on ethanol under steady-state conditions was studied. As a cultivation device, an aerated Chemap fermentor combined with continuously working gas analyzers for oxygen and carbon dioxide was used. Dry matter, substrate concentration, yield, specific oxygen uptake, specific carbon dioxide release, and respiration quotient, as well as nitrogen, carbon, phosphorus, hydrogen, and protein content of the cells were measured in dependence on the dilution rate. Cell size distribution, as a function of the specific growth rate, was determined with the aid of a Celloscope 202. A fair agreement with the theory of continuous culture for all metabolic curves could be established. An increased turnover rate resulted from the addition of glutamic acid to the synthetic growth medium. The primary effect of this supplement could be a rise in the flow rate of the tricarboxylic acid cycle.
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  • 25
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    Biotechnology and Bioengineering 10 (1968), S. 238-242 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: We have recently constructed a 10-mm, light path quartz cuvet which will accept a Clark oxygen electrode; it is temperature controlled and is suitable for use in a Unicam (Cambridge, England) SP 800 recording spectrophotometer. Several enquiries have prompted this publication, although such an apparatus was mentioned much earlier by Chance and Williams,1 and has been used extensively.Figure 1a, b, c, and d and their legends provide sufficient detail for the construction of the cuvet and provision of the commercially available electrode, quartz faces, stirring motor and disk magnet. Circuit diagrams for temperature control (range 22-38°C., ± 0.2°C.) and stirrer speed control are shown in Figure 2a and b. The cuvet is shown situated in the spectrophotometer cell housing in Figure 3, and the cuvet with its associated equipment is shown in Figure 4.
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  • 26
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    Biotechnology and Bioengineering 10 (1968), S. 815-828 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The intracellular levels of seven enzymes in mouse LS cells growing in suspension culture at controlled dissolved oxygen partial pressures (pO2) have been measured. During the growth of each culture large fluctuations were observed in the levels of some enzymes, particularly aldolase and cytochrome oxidase. Mean values for the concentration of each enzyme during the growth phase have been calculated. These results are discussed in relation to previous observations made on the growth of mouse LS cells.
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  • 27
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    Biotechnology and Bioengineering 10 (1968), S. 865-875 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Continuous cultivation of the yeast Candida lipolytica on gas oil was studied from the viewpoint of biomass production and oil deparaffination. Optimum conditions wore found at the dilution rate D = 0.16-0.19 when biomass productivity 1.7 g/l/hr and yield coefficient. y = 0.92 were achieved. At deparaffination to the same freezing point, more than double the production of biomass and deparaffined oil during a given time unit was achieved in a continuous process than in batch cultivation. Consumption of substrate was followed in both cultivation processes and it was confirmed that individual n-alkanes of gas oil were degraded at various rates and yields. Results proved optimum cultivation conditions to depend on concentration and composition of the paraffinic fraction of gas oil used. To achieve these conditions the continuous process may be controlled by choice; of suitable dilution rate and concentration of gas oil.
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  • 28
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    Biotechnology and Bioengineering 10 (1968), S. 69-82 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The authors have utilized a previously proposed mathematical equation (introduced originally for development of empirical equations) as a useful tool for evaluation of first-order reaction rate constants. By assigning physical significance to the parameter α, the equation can be utilized in obtaining excellent estimates for limiting boundary values and velocity constants.
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  • 29
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    Biotechnology and Bioengineering 10 (1968), S. 151-157 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dried vaccinia virus was found to be very stable in aerosol form in our chamber at a temperature of 75°F and a relative humidity (RH) of 85% when the virus was protected with 1.5% lysine, 1.5% sodium glutamate, 0.5% isoniazid, 0.5% thiourea, and either 2.5% heart infusion broth (HIB) or a combination of 3.75% lactose plus 1.25% raffinose prior to freeze-drying. Utilization of the Environmental chamber technique resulted in (a) selection of two diluents which protected vaccinia virus against the effects of high relative humidity, (b) measurement of the effect of various chemical additives in the diluents, and (c) quantitative measurement of the moisture absorbed by the various dried products.
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  • 30
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    Biotechnology and Bioengineering 10 (1968), S. 189-203 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The biochemical oxygen demand (BOD) of a complex, partially colloidal substrate is divided into oxidation (fo) and synthesis (fs) fractions. The substrate being investigated is a suspension containing 10 mg./l. of dry skim milk. The oxidized and synthesized fractions of the BOD are shown to be 38.4% and 61.6%, respectively. The division of BOD is related to the time at which maximum cell growth appears. The time required to obtain maximum cell production is shown to be at least 10 hr. The relationship between the time to maximum cell production and the apparent initial activity of the seed organisms is discussed.
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    Biotechnology and Bioengineering 10 (1968), S. 247-251 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 32
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    Biotechnology and Bioengineering 10 (1968) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 33
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    Biotechnology and Bioengineering 10 (1968), S. 89-98 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The foam separation technique of microflotation was studied using A. aerogenes as the test organisms. Gas flow rate, collector and alum (when used) concentrations, and frother dose were held constant. In contrast to E. coli, previously reported, A. aerogenes are removed using both lauric acid and laurylamine as the collectors without prior coagulation with alum. The removals are improved after coagulation, with laurylamine being the more efficient collector. In all cases the removals decrease upon increasing the pH above about 8.
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  • 34
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    Biotechnology and Bioengineering 10 (1968), S. 133-150 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The rate of dissolution and dehydration of CO2 in a liquid model system was investigated. Components in the model system established the main conditions which may exist, in the extracellular space of a microbiological culture liquid. The charge in voltage of a glass electrode was measured which indicated the formation of H+ ions in the H2CO3 ⇌ HCO3- H+ reaction. The rate of CO2 hydration increased with the increase of temperature from 0 to 40°C. Likewise the equilibrium of the reaction was shifted towards the forward reaction. Similar results were observed when the tip velocity of the impeller was increased. Data suggest that agitation promotes the dissolution of CO2 in the culture liquid through the reduction of gas-liquid film resistance in the diffusion of this gas. The rate of hydration of CO2 into the bulk of the liquid was independent of pCO2 above the surface of the liquid but depended on pCO2 in the gas bubble within the liquid. The concentration of HCO3- was, furthermore, influenced by the buffer components, buffer capacity, and the viscosity of the system. Since pCO2 and the HCO3- concentration in the extracellular space depend on both physical and chemical factors, the ventilation of a culture liquid necessitates both exhaust of CO2 from the gas bubbles of the culture broth and shift of the H2CO3 ⇌ HCO3- + H+ reaction towards the backward direction.
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  • 35
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    Biotechnology and Bioengineering 10 (1968), S. 233-237 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method for the determination of total heat generation in a fermentation tank and overall heat-transfer coefficient at the cooling surface is outlined. These data, which are essential for the design of cooling systems, are measured during the actual fermentation by dynamic analysis of controlled temperature variations. Each experiment consists of two stages: one in which cooling is cut off, and one in which cooling is constant. The necessary temperature variation is so limited that, the course of the fermentation is not affected.
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  • 36
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    Biotechnology and Bioengineering 10 (1968), S. 877-889 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A survey of interactions of membrane filters with viruses has included 28 types of membranes, 4 types of enteroviruses, and 1 reovirus. Losses of these viruses in filtration, due to adsorption to the filter membranes, appear to be governed by three factors: the chemical composition of the filter membrane, the ratio of pore diameter to the diameter of the virus particle, and the presence of substances, such as those occurring in serum, which interfere with adsorption. Membranes of cellulose triacetate and of certain other materials have a very low affinity for these viruses. Cellulose triacetate filters adsorb virtually none when the pore size exceeds the virus diameter by a factor of more than 3. At porosities nearer the virus diameter, even low-affinity membranes adsorb large quantities of virus unless serum or some other additive interferes. Cellulose nitrate membranes, in the absence of interfering substances, adsorb enterovirus significantly at a pore size 285 times the virus diameter.
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  • 37
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An interesting cholinergic compound has been isolated from the fungus Rhizoctonia leguminicola grown on extracts of red clover hay. The compound was characterized as 1-acetoxy-8-aminooctahydroindolizidine and given the name “slaframine.” It has been shown that slaframine is not the active compound but is converted to the active metabolite by liver microsomal enzymes. Physiological studies with slaframine point out that it is a potent stimulator of exocrine glands. In addition, its long duration of action and low toxicity suggest that it may have therapeutic value. Preliminary data suggest that slaframine is a potent stimulator of pancreatic activity, and its long duration of action results in a stimulation of protein synthesis by the gland.
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  • 38
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    Biotechnology and Bioengineering 10 (1968), S. 698-706 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A rocker mammalian cell culture system is described. The basic mechanical component is a special incubator with contained rocker culture trays. The system provides for precise environmental temperature regulation with intermittent rocking of contained cultures in such a manner as to permit thin fluid overlay of cells with maximum accessibility to oxygen while circumventing the problems of evaporation, substrate depiction, etc.
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  • 39
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    Biotechnology and Bioengineering 10 (1968), S. 741-763 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Mathematical models have been constructed which relate the depth of the culture fluid overlay to the oxygen available to mammalian cells cultured under static conditions. These models suggest that the maintenance of a given rate of oxygen utilization by some culture systems may be critically depended on this fluid depth and on the solubility and rate of diffusion of oxygen in the culture fluid. The importance of these concepts as applied to the isolation and growth of differentiated cells representative of the tissue of origin are noted.
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  • 40
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    Biotechnology and Bioengineering 10 (1968), S. 303-320 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A novel and convenient method for the synthesis of guanosine is described. The reaction of AICA-riboside with sodium methylxanthate gave 2-mercaptoinosine in almost quantitative yield. The latter was oxidized with hydrogen peroxide to afford inosine-2-sulfonic acids, which was readily animated to give guanosine in excellent yield. Similarly, the preparation of N2-methylguanosine and N2,N2-dimethylguanosine, minor constituents of transfer RNA, was also accomplished. Furthermore, this procedure was extended to the synthesis of 2′,3′-O-isopropylideneguanosine and the isopropylidene derivatives of various N2-substituted guanosines from 2′,3′-O-isopropylidene-AICA-riboside. Guanosine via 2′,3′-O-isopropylideneguanosine was successfully phosphorylated to give 5′-guanylic acid.
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  • 41
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A HeLa cell line was propagated in semicontinuous suspension culture, 85 liters final volume, and in continuous flow culture with a volume of 300 ml. or 5 liters in an autoclavable medium to which 8% calf serum had been added. A medium containing 0.1% Methocel and 2% calf serum was also tested. Maximum productivity was obtained at a dilution rate of 0.33 day-1 with a cell density of about 1.0 × 106 cells/ml. The same cell line was also infected with Rubella virus and the production of virus was followed at the 5-liter cultivation level.
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  • 42
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    Biotechnology and Bioengineering 10 (1968), S. 385-397 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The purpose of this experimental study was to examine the transient response of a chemostat-type continuous culture of Escherichia coli B to step changes in temperature by following transient limiting substrate concentration and calculating from it the transient growth rate. The transient response to step changes of temperature was tested for four different situations. In the first two cases, temperature was shifted down from 37 to 27°C., and 37 to 32°C. In the last two, it was shifted up from 32 to 37°C., and 27 to 37°C. When the temperature was shifted up, the growth rate increased rather rapidly to its transient maximum value and then decreased slowly until it, settled back into the steady-state value. On the other hand, when the temperature was shifted down, the growth rate decreased relatively rapidly to its transient minimum and then it slowly increased and returned gradually to the steady-state value. The magnitude of the transients was less than would be expected if the transient growth rates followed an Arrhenius function.
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  • 43
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Colisan has the formula Lys3Val4Leu3IleTyr and a molecular weight of approximately 1500. Neither N-terminal nor C-terminal group have been found. The peptide is highly resistant to hydrolysis by proteolytic enzymes (pepsin and trypsin). The ∊-amino groups of lysine are indispensable for biological activity, since either deamination or acetylation completely inactivates Colisan. A comparative study with basic peptides like polylysine demonstrated their similarity of action, on one hand, and an antagonistic effect to Colisan, on the other. The fast action of the antibiotic and the specific effect on the cell membranes of many different biological systems (Entameba, Paramecium, erythrocytes, smooth muscle, and others) support the hypothesis that the primary damage occurs in the membrane with consequent alteration of permeability. The leakage of intracellular material (histamine) from mast cells after application of Colisan is in accord with this hypothesis. The results strongly suggest that the biological activity of the peptide is based essentially, but not exclusively, on its basic character.
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  • 44
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    Biotechnology and Bioengineering 10 (1968), S. 535-549 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An automatically working test arrangement for the permanent analysis of O2 and CO2 in microbiological cultures is described. The measuring principle is based on the paramagnetic properties of oxygen and on the absorption of infrared by carbon dioxide. The preparation of the gas for measuring and the correction of the recording are indicated. The formula of correction was programmed and the values were calculated for a range of 3%. The routine correction of analysis values is done with a nomogram established on the basis of these individual values. The advantages of the described test arrangement are illustrated by two examples of growth experiments on Saccharomyces cerevisiae.
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  • 45
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    Biotechnology and Bioengineering 10 (1968), S. 551-552 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 46
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    Biotechnology and Bioengineering 10 (1968), S. 497-510 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An analysis is presented of the effects on substrate utilization and cell growth of varying the volume distribution of and the input distribution to a model continuous-culture unit consisting of three stirred tanks. The model is used to establish the best volume and input distributions and to indicate the effects of mixing imperfections. The Michaelis-Menten rate expression is utilized, including an endogenous respiration term, and results are presented on unique triaxial charts. Of the distributions considered, maximum substrate utilization is achieved with 60% of the total volume in the first stage, 20% in the second stage, and 20% in the third stage and with all of the input to the first stage. At a constant fractional input to the third stage; variation in the ratio of inputs to the first and second stages has virtually no effect, except in the case that a critical dilution is exceeded. At a constant input ratio to the first two stages, an increase in the fractional input to the third stage always decreases efficiency. Three stages, regardless of relative size, are always better than one. Except for endogenous respiration effects, cell growth parallels substrate utilization.
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  • 47
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    Biotechnology and Bioengineering 10 (1968), S. 483-496 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effect of NaCl on the yield of biological solids and on the ability of continuously cultured heterogeneous microbial populations to remove substrate was assessed by changing the salt concentration in the inflowing synthetic waste. During the period of increasing the salt concentration to 30,000 mg/l the system could not maintain a high substrate removal efficiency. However, after an acclimation period the system regained its former efficiency. Upon diluting the salt out of the system, a significant rise in cell yield was noted as the salt level passed through the range 8,000-10,000 mg/l. It was found that steady operation at a salt level of 8,000 mg/l sustained the cell yield at a high level.
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  • 48
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    Biotechnology and Bioengineering 10 (1968), S. 567-587 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Virus quantitation is discussed stressing the discrepancy between the biological titer and the physical virus particle count. When both these techniques are used in conjunction, one can more realistically catalog viral properties. The merits of this technique are exemplified in a study of the growth kinetics and properties of vesicular stomatitis virus in tissue culture.
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  • 49
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    Biotechnology and Bioengineering 10 (1968), S. 617-624 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new concept of tissue culture equipment and procedures was developed for the mass-scale growth of several types of animal tissue cells in monolayers on multiple glass surfaces. Continuous, cell lines, primary and diploid cell strains were grown in this equipment. Cells studied include primary bovine kidney, human diploid WI-38, human foreskin, and mouse CCL1 cells. Photomicrographic comparisons of cells grown by these techniques indicate they are morphologically identical to tissue culture cells grown in glass bottles or tubes. The growth of the tissue culture cells in the propagator was monitored by carbohydrate Utilization and acid production. Large-scale production of viruses and biochemicals on cells grown in the multiple-plate tissue culture propagator was accomplished. Virus titers were equal to those obtained from conventional bottle or tube cultures for several strains of influenza, parainfluenza, and respiratory syneytial viruses. High-titred mouse interferon was also produced in this system. In addition to tissue culture cell production, Eaton agent, Mycoplasma pneumoniae was grown on the multiple glass surfaces on a mass scale.
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  • 50
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    Biotechnology and Bioengineering 10 (1968), S. 681-683 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 51
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    Biotechnology and Bioengineering 10 (1968), S. 689-692 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 52
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    Biotechnology and Bioengineering 10 (1968), S. 707-723 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model is presented for both batch and continuous cultures of microorganisms utilizing inhibitory substrates. The key feature of the model is the use of a inhibition function to relate substrate concentration and specific growth rate. Simulation studies show that the primary result of inhibition by substrate in a batch culture is an increase in the lag time whereas in continuous culture inhibition by substrate may result in process instability. The model should be of value in investigations of the stability of biological processes used for the treatment of certain industrial wastes such as those containing phenols, thiocyanates, nitrates, ammonia, volatile acids, etc., which are known to be inhibitory to many of the organisms metabolizing them.
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  • 53
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    Biotechnology and Bioengineering 10 (1968), S. 33-43 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The growth of batch-cultivated yeast Candida lipolytica on three kinds of gas oil using mineral medium was studied. A linear dependence was found between the production of yeast biomass and the consumption of n-alkanes, while the decrease of freezing point of gas oil during cultivation had a distinct course. This disproportion was explained by different degradation of individual n-alkanes contained in gas oil. The rate of degradation of pentadecane, hexadecane, and heptadecane was the same during the entire cultivation. On the contrary, in the first phase the utilization of shorter chain n-alkanes, nonane to tetradecane, was more rapid while that of longer chain homologs, octadecane to pentacosane, lagged. Rapid utilization of longer chain n-alkanes did not occur before the concentration of the other n-alkanes decreased. Only then the rapid decrease of freezing point appeared.
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  • 54
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    Biotechnology and Bioengineering 10 (1968), S. 45-59 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The influence of agitation and aeration on growth and on production of glucose oxidase of Asp. niger has been studied. It was found that both rate of growth and glucose oxidase production was higher at an agitation speed of 700 rpm than at 460 rpm. Further increase in speed of agitation resulted in neither a higher rate of growth nor a higher glucose oxidase activity. Total glucose oxidase activity was highest in a medium containing 5% sugar (at an agitation speed of 700 rpm) and did not get higher when the sugar concentration of the medium was increased to 7%. When pure oxygen was bubbled through the culture the rate of growth of the culture (in the linear phase) was 95 mg. mycelial dry wt./100 ml./hr., and only 61 mg. when air was applied. The glucose oxidase activity of oxygenated culture was double the activity of aerated culture. Viscosity of the homogenized culture became higher with higher concentration of mycelia. The viscosity of oxygenated culture was found to be lower than that of aerated culture.
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  • 55
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    Biotechnology and Bioengineering 10 (1968), S. 99-101 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 56
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    Biotechnology and Bioengineering 10 (1968), S. 105-131 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: As a rate equation of microbial cell growth, the Monod equation is widely used. However, this equation cannot fully correspond to real courses of microbial cell growth in many batch cultivations. Especially, predicted values based on this equation do not agree with observed values in many continuous cultivations. In this paper, which introduces new concepts of critical concentration and coefficient of consumption activity, the growth rate equation which corresponds to the whole period including lag period is newly derived and characteristics of microbial cell growth in batch cultivation are clarified. Further, applying the new rate equation to continuous cultivation, a general equation with which to calculate cell concentration is derived and characteristics of microbial cell growth in continuous cultivation are clarified. The calculated values of cell concentration based on the new theory showed quite good agreement with the observed values in both batch and continuous cultivation.
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  • 57
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    Biotechnology and Bioengineering 10 (1968), S. 177-188 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This is the first part of a systematic study on the mechanisms of the Waldhof fermentor. When an agitator is rotating in a liquid, a vortex will develop on the surface. Air is dispersed into the liquid when the vortex is deep enough to reach the agitator. This is the basic mechanism of air dispersion in a Waldhof fermentor. In this work, experimental results, empirical correlations, and theoretical equations were obtained to relate the vortex depth to a number of physical factors including agitator diameter, agitator speed, tank diameter, liquid depth, liquid viscosity, and so on. The vortex depth was found a function of both Reynolds number and Froude Number.
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  • 58
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    Biotechnology and Bioengineering 10 (1968), S. 243-246 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 59
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    Biotechnology and Bioengineering 10 (1968), S. 255-255 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 60
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    Biotechnology and Bioengineering 10 (1968), S. 291-302 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A major problem involved in the direct fermentation of nucleotides is their breakdown by phosphohydrolases. Thus, adenine auxotrophs of most microorganisms produce hypoxanthine and/or inosine rather than inosine 5′-monophosphate (IMP) while guanine auxotrophs excrete xanthosine rather than xanthosine 5′-monophosphate (XMP). Examination of a Bacillus subtilis mutant producing hypoxanthine plus inosine revealed at least four phosphohydrolases, three of which could attack nucleotides. Even when the extracellular nucleotide phosphohydrolase was inhibited by Cu+2 and its surface-bound alkaline phosphohydrolase was repressed and inhibited by inorganic phosphate, or removed by mutation, the breakdown products were still the only products of fermentation. Under these conditions, the third enzyme, a surface-bound non-repressible nucleotide phosphohydrolase was still active. It appears, at least in B. subtilis, that excretion is dependent upon breakdown by this enzyme and if hydrolysis does not occur, excretion of purine nucleotides is feedback inhibited by the resultant high intracellular IMP concentration. Corynebacterium glutamicum mutants, on the other hand, can excrete intact nucleotides, and direct fermentations for IMP, XMP, and GMP have been described. An examination of phosphohydrolases in a GMP-producing culture revealed no extracellular or surface enzymes. Disruption of the cells resulted in liberation of cellular phosphohydrolase activity with a substrate specificity remarkably similar to the flavorenhancing properties of the 5′-nucleotides. The order of decreasing susceptibility was GMP, IMP, XMP; AMP was not attacked.
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  • 61
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    Biotechnology and Bioengineering 10 (1968), S. 359-372 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Polyribonucleotide: orthophosphate nucleotidyl transferase, commonly known as polynucleotide phosphorylase catalyzes the reversible polymerization of ribonucleoside diphosphates with the liberation of orthophosphate. The equilibrium constant is approximately 1.0. Although isolated from a variety of sources, the enzyme occurs essentially as two types: one which does not require a primer for reaction initiation and a second which does. A parallel study of an E. coli preparation representing the first type and an M. lysodeikticus preparation representing the second showed differences other than the primer requirement. Rates of polymerization were different as were the Kms. The E. coli preparation catalyzed the synthesis of polyguanylic acid while the M. lysodeikticus preparation did not although synthesis of hetoropolymers containing guanylic acid was catalyzed by the M. lysodeikticus enzyme. Use of repurified commercial substrates made the validity of some primer-requirement experiments suspect. End group analysis of product polymers served only to raise questions concerning the reaction-initiating compounds and the reaction mechanism. A study of hetero-polymer synthesis showed not only that the rate of polymerization was different, from that of homopolymers but that uncompetitive inhibition rather than competitive inhibition occurred when two ribonucleoside diphosphates were present in the reaction mixture. Furthermore, the experiments showed a preferential uptake of one substrate over another and an “enrichment” which was constant. It has also been shown that RNA polymerase, a DNA-RNA directed polymerase, can be used to synthesize polyribonucleotides if the appropriate template is provided.
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  • 62
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    Biotechnology and Bioengineering 10 (1968), S. 413-427 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Substances which cause emesis in pigeons were extracted from corn (Zea mays) artificially inoculated with Fusarium graminearum and from liquid culture medium inoculated with F. moniliforme, F. roseum, F. poae, F. culmorum, and F. nivale. Emetic preparations were obtained also from infected wheat (Triticum aestivum L. em. Thell), (Hordeum vulgare L. em. Lam), and durum (Triticum durum Desf). Partial purification resulted from chromatography with columns of cellulose and DEAE cellulose and with thin layers of silica gel. Two active materials were obtained from liquid culture of F. moniliforme but only one from infected cereals. Emetic preparations from F. moniliforme and infected cereals contained a polypeptide as a minor component. Ultraviolet and infrared spectrums, elemental analyses, refractive indices, and amino acid composition of the emetic from corn and one of the emeties from liquid culture of F. moniliforme were similar but not identical. Attempts to crystalline these emetics and to characterize them were unsuccessful.
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  • 63
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    Biotechnology and Bioengineering 10 (1968), S. 469-482 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 64
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    Biotechnology and Bioengineering 10 (1968), S. 553-553 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 65
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    Biotechnology and Bioengineering 10 (1968), S. 557-566 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A procedure to maintain genetic control of virus production in tissue cell lines, has been proposed and discussed. Both the tissue cell which replicates the virus and the virus inoculum must be homogeneous in order to produce a product with the expected characteristics. Certain philosophical and technical aspects of the problem are discussed in relation to developing and maintaining genetically homogeneous stock cultures, inoculum, and product.
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  • 66
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    Biotechnology and Bioengineering 10 (1968), S. 625-640 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies of the possible viral etiology of human leukemia have required large quantities of cultured cells derived from human hematopoietic tissues. Since cultures sufficiently large and free from contamination could not readily be produced according to existing methods, a pilot, cell culture plant has been constructed for the production of mammalian cells in mass quantity. 500-ml to 20-liter trophocell units have already proved to be scientifically and economically practical, as they provide good reliability, excellent growth rates, and sustained yield of human cells. 200-liter stainless steel culture units have now been added to the trophocell system. Five complete 200 liter units are now in operation. The design of the original stainless steel unit was based on that of a stainless steel, jacketed soup kettle. There are no openings in the vessel other than those in the lid, which provide convenient access points for sampling, sensor probes, etc. Environmental parameters, e.g., liquid level, temperature, and pH, are monitored and controlled with commercially available apparatus. Many initial problems connected with the new 200 liter units have been resolved, but operational and design problems remain in the areas of stable instrumentation, cell harvesting, salvaging and reuse of unspent media components, establishment of physiologic steady stale, recovery of virus-containing cells with reculture of the remaining unaffected cells, and the recovery and separation of cell components and special products such as immunoglobulins, interferons, and hormones. A definitive cell plant with culture units of 20, 50, 250, and 1250 liters is now being constructed.
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  • 67
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    Biotechnology and Bioengineering 10 (1968), S. 669-675 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: New trends and developments in vaccines emphasized the growing need for safety tests of increased complexity, rather than a need for ultrasophisticated and complex devices. The Vaccine Development Branch of the National Institute of Allergy and Infectious Diseases, operating with an annual budget of $6,000,000 has the task of expediting the collaborative efforts of 50 laboratories for developing, producing, and testing experimental vaccine lots. Rubella has a major priority; other priorities are assigned to respiratory syncytial, parainfluenza, adenoviruses, influenza, and rhinoviruses, and Mycoplasma pneumoniae. To accomplish this requires a very expensive and complex program involving rapid information exchange and increased emphasis on safety testing with regard to extraneous viruses and the oncogenic potential of the vaccines. The latter need resulted from such experience as that with the Salk vaccine and the tumorproducing potential of some adenoviruses. Electron microscopy has been useful in discovering possible viral contaminants. Of all material produced for experimental work, from 65 to 70% is used for safety tests.
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  • 68
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    Biotechnology and Bioengineering 10 (1968), S. 693-697 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 69
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    Biotechnology and Bioengineering 10 (1968), S. 725-740 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It has been demonstrated experimentally that the thickness of fluid overlay in conventional tissue culture systems limits the oxygen available to mammalian cells growing as a submerged monolayer. A rocker culture system is described which circumvents critical problems associated with thin film culture while permitting nearly unlimited access of oxygen to the cell monolayer. Good growth of primary hepatic cells as isolated sheets has been obtained.
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    Biotechnology and Bioengineering 10 (1968), S. 801-814 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A 3-liter culture vessel has been developed for the growth of animal cells in suspension at controlled pH and dissolved oxygen partial pressure (pO2). The culture technique allows metabolically produced CO2 to be measured; provision can be made to control the dissolved CO2 partial pressure. In cultures containing a low serum concentration, gas sparging to control pO2 was found to cause cell damage. This could be prevented by increasing the serum concentration to 10%, or by adding 0.02% of the surface-active polymer Pluronic F68. The growth of mouse LS cells in batch culture without pO2 control was found to be limited by the availability of oxygen. Maximum viable cell populations were obtained when dissolved pO2 was controlled at values within the range 40-100 mm Hg.
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  • 71
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    Biotechnology and Bioengineering 10 (1968), S. 511-533 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A Candida sp. was grown on a fraction of n-alkanes (dodecane 22%, tridecane 48%, tetradecane 28%) as sole carbon source. The growth rate was increased most markedly by using high concentrations of n-alkanes (16.7% v/v). When grown in a 5 liter fermentor, the yeast reached its highest yield (60 g. of cell dry wt/l) with a concomitant high yield of fatty acids (21 g of fatty acids/l), by using a nitrogen-deficient medium. To achieve good growth, it was essential to use an inoculum (1 part into 10) of rapidly growing cells and beneficial to increase the agitation rate gradually once growth had begun. After 108 hr maximum conversions of substrate to product were: 71.5% (w/w) for alkanes into cells and 24.8% (w/w) for alkanes into fatty acids. Of the, total fatty acids at the end of the fat-accumulating phase of growth 54% were shorter in chain length than palmitic acid (C16H32O2). When grown on glucose, as sole carbon source, less than 2% of the total fatty acids were shorter than palmitic acid. When n-alkanes were added to cells growing on glucose, short-chain fatty acids (C10 to C14) were synthesized immediately, indicating a derepressed enzyme system for hydrocarbon assimilation and the absence of diauxie. The production of these acids was at the apparent sacrifice of linoleic acid synthesis. In spite of the high conversion ratios, it is concluded that it would be uneconomical to produce fatty acids, even expensive ones such as lauric acid, by microbial transformation of n-alkanes.
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  • 72
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    Biotechnology and Bioengineering 10 (1968), S. 555-555 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 73
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    Biotechnology and Bioengineering 10 (1968), S. 601-615 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Various multisurface mass-scale tissue culture propagators ranging in capacity up to 200 liters have been developed at Abbott Laboratories. These patented units consist, of an enclosed vessel containing a multiplicity of separated glass plates or disks on which cells may attach and proliferate. Means for mixing and aeration of the medium are provided. Sample ports facilitate the addition of cultures and media, the withdrawal of samples, the washing of cell monolayers, and the harvesting of cells and cell products. The large cell growth surface per occupied volume, the provision for separating tissue cells from media simply and easily, and the minimization of the amount of labor required per cell growth area are some of the many advantages of the multisurface tissue propagator that are described.
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  • 74
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    Biotechnology and Bioengineering 10 (1968), S. 651-668 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The herpes-type virus found in certain cell cultures derived from Burkitt's lymphoma, other human leukemias, and normal human leukocytes, was concentrated and partially purified by large-volume density gradient centrifugation using zonal centrifuge systems. Using the Jiyoye (P-3) cell line as a model, rate-zonal runs on disrupted cell suspensions in sucrose gradients yielded concentrates with high virus particle counts when 10-15 ml of packed cells were processed per liter of gradient. Isolation and removal of cell nuclei or fluorocarbon treatment of cell sonicates permitted virus recovery from larger volumes of cells per experiment. Zonal centrifugation of concentrated cell-free spent media from highly infected cell cultures yielded more purified virus than obtained from cells. Viral concentrates were prepared with particle counts of 1010-1011/ml and total protein concentrations of 0.2-0.5 mg/ml. Subsequent isopyenie-zonal centrifugation of the various high-count virus fractions from the zonal centrifuge showed a heterogeneity in buoyant virus density ranging from 1.18 to 1.27 in potassium tart rate. The spread in virus density was attributed to the different morphological forms of the virus observed by electron microscopy.
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  • 75
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    Biotechnology and Bioengineering 10 (1968), S. 677-680 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The production of large quantities of microbial mass, or their by-products, frequently requires aeration and mixing of fluid media. This operation often results in copious production of foam which cannot be exhausted with the effluent air or gas. Foam is usually controlled with antifoam agents which may interfere with product purity, oxygen uptake, and with subsequent product, handling. The process herein described obviates the requirement for antifoam agents or other foam-control methods. In essence, the air (or other gases) and foam in the headspace are continuously withdrawn, entrained in the intake side of a self-priming pump, and reintroduced into the bulk of the process liquid medium. The headspace may be enriched with oxygen or other gases.
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  • 76
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    Biotechnology and Bioengineering 10 (1968) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 77
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    Biotechnology and Bioengineering 10 (1968), S. 1-31 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Although the basic parameters for ethylene oxide sterilization are established, it is sometimes difficult to attain in practice where the principal limiting factor is moisture availability. There are situations which can limit or enhance the dynamics of sterilization. Such factors, if overlooked, could upset experiments and lead to erroneous conclusions, or defeat the sterilization process entirety. Such are, namely: stratification effects, diffusion barriers, moisture-reducing effects, polymerization, and temperature distribution gradients.
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  • 78
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    Biotechnology and Bioengineering 10 (1968) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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  • 79
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    Biotechnology and Bioengineering 10 (1968), S. 589-599 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Baby-hamster kidney (BHK) cell cultures grown in rolling 2-liter Baxter bottles are used for the production of foot-and-mouth disease virus (FMDV) which is subsequently purified. The bottles are held securely in round wire racks (19 per rack) and rotated on a three-tiered roller mill. The use of a strongly buffered growth medium makes changes of the medium unnecessary. A sheet of aluminum foil is used to seal the cultures. It is pressed tightly over all the bottles in a rack by means of a polyurethane foam sheeting bonded to the underside of a rigid snap-on cover. Special equipment eliminates removing the bottles from the racks at any stage in their use. The loaded racks fit directly onto headers of a glassware washer. Spent cell growth media and virus fluids are collected by inverting an entire rack of bottles-Current production is 400 BHK cultures (21 racks) containing 8 × 108 cells each after 6 days growth. About 344 of these cultures (18 racks) are used to grow virus. The purification process yields about 113 mg of pure FMDV per week; the overall recovery based on infectivity is 32%. The projected maximum production of purified virus in the present facilities is approximately 2.5 times greater than this amount.
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  • 80
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This study reports some findings on the effects of centrifugation on the viability of mammalian cells. The authors used Burkitt lymphoma cells cultivated in a synthetic medium containing 10% fetal calf serum for all experiments. Batch centrifugations were conducted in a RC2-B centrifuge (Ivan Sorvall, Incorporated, Norwalk, Connecticut USA) operated at 0 and 25°C. During centrifugation we exposed the cells to gravitational fields ranging from 24,800 to 42.200g. The results showed that at, 0°C and 25,800 or 42,000g no loss in cell viability occurred for up to 90 min exposures in the centrifugal field. However, at 25°C and for gravitational fields of 24,800 and 42,000g, there were appreciable losses in cell viability. Continuous centrifugation studies in the Sharples supercentrifuge (Division of Penn Salt Corporation, Warminister, Pennsylvania USA) were also conducted with bowl speeds up to 28,000 rpm (19,000g) and flow rates ranging from 1.4 to 20 1, hr. Slight, losses in cell viability were noted and postulated as caused by the shear stresses encountered by the cells. Some pumping studies using the lymphoma cells substantiate this conclusion.
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  • 81
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    Biotechnology and Bioengineering 10 (1968), S. 684-688 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Equipment has been developed for the recovery of precipitates from rotors of industrial tubular centrifuges. A double piston is described for nonaseptic discharge of precipitates through the outlet holes of the clarifier rotor. For the aseptic resuspension or dissolving of valuable precipitates a closed-circulation system has been developed, which is applied without opening of the clarifier rotor.
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  • 82
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    Biotechnology and Bioengineering 10 (1968), S. 765-785 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two experimental methods were used in measuring oxygen-transfer rates. The results indicate that two possible mechanisms are operating in simultaneous gas-liquid interfacial oxygen absorption and biochemical oxidation. One of the mechanisms, the direct absorption mechanism, has not been much studied in bioengineering. Mathematical equations are derived to describe the simultaneous mechanisms.
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  • 83
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    Biotechnology and Bioengineering 10 (1968), S. 829-843 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A laboratory process for the isolation of type B acid phosphatase from human erythrocytes has been scaled up 80 times. The enzyme was purified 1300-fold by adsorption on calcium phosphate gel, ammonium sulfate precipitation, and gel filtration. The yield was 27%. Results for the type A enzyme are also presented.
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  • 84
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    Biotechnology and Bioengineering 10 (1968), S. 845-864 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The inhibitory effect of ethanol concentration p in a medium on the specific rates of growth μ and ethanol production ν of a specific strain of baker's yeast was studied in a chemostat, where except for ethanol as the product, only the concentration of glucose S was controlled to limit the metabolic activity of the yeast. This was designed to supplement the previous findings from the batch experiment, in which ethanol was added artificially and no substrate components were limiting the metabolism of the same yeast, that μ = μ0e-k1p and ν = ν0e-k2p, where k1 and k2 are empirical constants and subscript the 0 denotes respective values at p = 0. The effects of p on the values of μ and ν were confirmed by the Lineweaver-Burk plot to belong to noncompetitive inhibition. The formulas here for μ and ν as affected by p, if extrapolated to the case of no limiting substrates, were in good agreement in respective forms with those derived previously from the batch experiment, though the values of corresponding coefficients in these formulas were different. The differential equations for μ and ν as functions of both p and S and, in addition for the rate of glucose consumption as correlated by the yield factors either with the cell growth rate or the rate of ethanol production, were solved properly with a digital computer. A kinetic, pattern calculated so far was discussed with reference to the data obtained in the batch experiment and those relevant to actual “sake” brewing.
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  • 85
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    Biotechnology and Bioengineering 10 (1968), S. 61-67 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A relatively simple, autoclavable medium was developed that would support the growth of the mouse fibroblast (MFL) cell line in suspension culture. This medium was prepared in three stages with decreasing quantities of serum. As the serum was reduced from 5% to none, the amount of Bacto-Peptone was increased from none to 0.5%. The reduction and finally elimination of serum did not affect proliferation adversely, but actually seemed to produce more rapid growth and higher levels of cell population.
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  • 86
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    Biotechnology and Bioengineering 10 (1968), S. 257-275 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Conditions for the efficient conversion of commercial RNA to nucleoside 5′-monophosphate by means of a phosphodiesterase in malt sprouts have been determined. A comparison of the enzyme content of the rootlets, stems, and kernels of various plant seedlings, including barley, rye, oat, wheat, rice, and beans shows maximum amounts in the rootlets, and minimum quantities in the ungerminated kernels. Of all the seedlings tested, (mung bean, soy bean, oat, wheat, rice, barley) barley gave the highest conversion of RNA to 5′-nucleotides. Commercial malt sprouts prepared from 6 different malted barleys including 2-rowed and 6-rowed samples all showed about the same amount of phosphodiesterase content. Besides phosphodiesterase, other enzymes capable of hydrolyzing RNA and 5′-nucleotides were found in sprouts. These included 3′-phosphodiesterases, 5′-nucleotidases, and nucleosidases. By carefully pretreating both extracts and the solid sprouts at elevated temperatures for a limited time and by the addition of minimum amounts of Zn+2, the action of these undesirable enzymes was either effectively destroyed or minimized so that the production of 5′-nucleotides was maximized. It was found that suspensions of appropriately washed and treated barley malt rootlets are substantially more effective than aqueous extracts for converting RNA to 5′-nucleotides.
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  • 87
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    Biotechnology and Bioengineering 10 (1968), S. 321-330 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Rat liver was subjected to three different, disruption procedures (homogenization, explosive decompression, and Chaikoff press) and mitochondria were subsequently isolated by conventional differential Centrifugation and by zonal Centrifugation. The properties of these mitochondria were investigated by polarographic measurement of oxygen uptake and they were examined by electron microscopy. All three methods of disruption gave mitochondria which showed respiratory control. Nitrogen cavitation gave the most reproducible conditions for cell breakage and zonal Centrifugation gave good separation of subcellular organdies in extracts produced by this method. Some separation of the heterogenous mitochondrial populations was achieved by zonal Centrifugation.
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  • 88
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    Biotechnology and Bioengineering 10 (1968), S. 399-402 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
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  • 89
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    Biotechnology and Bioengineering 10 (1968), S. 457-467 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Toxicological investigations were conducted on two new antibiotics, Muconomycin A and Muconomycin B. These non-nitrogenous antibiotics were found to be highly toxic and capable of inducing profound inflammation in the peritoneal cavity of male albino rats. Either antibiotic produced large volumes (10-20 ml) of inflammatory exudate even when injected intraperitoneally in quantities of 1.6 × 10-10 moles. An extensive profile of the electrolytes and proteins found in inflammatory exudates was developed. Simultaneous assays of the blood serum of treated rats provided a basis for comparing the concentrations of constituents of serum with those of the exudate. The results of these assays showed that the exudate contained lower concentrations of sodium and proteins, and greater amounts of potassium, calcium, and phosphorus than the serum. Chloride ion concentrations were variable. Since previous work showed that one of the manifestations of toxicity of these substances was the production of creatinuria, further studies were carried out with ATP/Creatine Phosphotransferase. These studies show that these antibiotics are potent in vitro inhibitors of the enzyme ATP/Creatine Phosphotransferase.
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  • 90
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    Biotechnology and Bioengineering 10 (1968), S. 102-103 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Tab.
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  • 91
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    AIChE Journal 14 (1968), S. 37-45 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper illustrates the synthesis of nonlinear feedforward controllers for chemical reactors. In most of the theoretical development and application of feedforward control only linear systems have been considered. There are, however, no inherent linear limitations in feedforward control. Since chemical reactors are usually nonlinear, the effectiveness of control should be improved by including nonlinearities in the design of feedforward controllers. This is particularly true for batch reactors because of the large changes in variables during a batch cycle. Continuous stirred-tank reactors are studied with single and consecutive reactions of first and higher order. Effectiveness of linear and nonlinear feedforward controllers is compared for disturbances of various magnitude and direction. Feedforward control of batch and tubular reactors is also discussed.
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  • 92
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    AIChE Journal 14 (1968), S. 57-61 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effect of standing waves of controlled amplitude and frequency on the steady state rate of mass transfer through thin horizontal liquid layers is studied experimentally. The variables studied are the film thickness, the amplitude and frequency of the waves, and the spacing between the probes generating the waves. A bulk motion of complicated pattern known as drift is caused by the finite amplitude of the waves. The rate of mass transfer in the absence of imposed vibration is two to three times greater than that expected by molecular diffusion alone. Vibration increases the rate up to an order of magnitude or more, depending on the hydrodynamic conditions. The data at low frequencies are correlated by an expression of the form (i-io)/idiff = KAf3/4h1/2L-1/2.
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  • 93
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    AIChE Journal 14 (1968), S. 85-91 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A general method has been developed for controlling deterministic systems described by linear or linearized dynamics. The discrete problem has been treated in detail. Step-by-step optimal controls for a quadratic performance index have been derived. The method accommodates upper and lower limits on the components of the control vector.A small binary distillation unit was considered as a typical application of the method. The control vector was made up of feed rate, reflux ratio, and reboiler heat load. Control to a desired state and about a load upset was effected.Calculations are performed quite rapidly and only grow significantly with an increase in the dimension of the control vector. Extension to much larger distillation units with the same controls thus seems practical.
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  • 94
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    AIChE Journal 14 (1968), S. 235-241 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The extraction of lanthanum and barium from single falling drops of the uranium-chromium eutectic into magnesium was studied at 1,000°C. Because of the short contact times involved, the data best fit the stagnant diffusion model for lanthanum. For barium, the fraction extracted was governed by external resistance of the magnesium phase. Drop velocities were adequately represented by the Hu-Kintner correlation.
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  • 95
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    AIChE Journal 14 (1968), S. 260-265 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The external velocity field associated with the fall of a single drop through a quiescent liquid phase is discussed. The field responsible for the transfer of vorticity from the point of generation to the disperse phase is assumed to be almost identical with the field that transfers mass from the drop interface. The stream surfaces associated with this field are made visible by means of dye trails. Since the field is not amenable to mathematical formulation, and since many reports appear in the literature concerning correlations between measurable flow parameters and the physical properties of the system, the field configurations relative to mass transfer mechanisms are considered qualitatively. The delineation of the flow patterns behind the drop gives some indication of the manner in which the external flow contributes to the transfer coefficients.
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  • 96
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    AIChE Journal 14 (1968), S. 275-279 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper presents an investigation of the equations of motion to find the conditions under which these equations admit exact viscometric solutions for certain unsteady torsional flows of incompressible simple fluids. In general, for the cone and plane and the parallel disk geometries, curvilineal solutions do not exist for arbitrary members of the class of simple fluids; however, if the inertia terms can be neglected in the equations of motion, curvilineal solutions can be found for the complete class of simple fluids.
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  • 97
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    AIChE Journal 14 (1968), S. 301-310 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper presents a theoretical study of the stability of chemical reaction on the external surface of a single spherical particle in stagnant surroundings. The analysis, which invokes methods of linear stability theory, yields necessary and sufficient conditions for stability of a steady state solution to small disturbances for the cases of very small and very large solid thermal conductivity. It is shown that heat losses from the solid surface may lead to transient behavior which is characteristically different from that for adiabatic surfaces, and that the unsteady state is strongly affected by the thermal capacity of the solid material. A numerical example is employed to illustrate the possible significance of unstable situations.
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  • 98
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    AIChE Journal 14 (1968), S. 311-317 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A comparison of the kinetic and diffusional models for solid-gas reactions occurring in a spherical particle is presented. The similarities and differences of the unreacted-core shrinking model and the homogeneous model are examined in light of the rate-controlling factors. In view of the similarity of the two models, it is shown that erroneous conclusions in regard to the mechanism and the activation energies may be drawn from an analysis of the experimental data. A more versatile model is presented in order to augment the two models so that wider varieties of solid-gas reaction systems may be treated. The concept of effectiveness factors in solid-gas reactions is introduced, and the influence of diffusion is ascertained.
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  • 99
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    AIChE Journal 14 (1968), S. 350-351 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 100
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 14 (1968), S. 356-356 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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