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  • 1970-1974  (3,368)
  • Life and Medical Sciences  (2,378)
  • Biochemistry and Biotechnology  (501)
  • Engineering General  (489)
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Year
  • 101
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 551-553 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Tab.
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  • 102
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: β-Amylase (EC 3.2.1.2) and pullulanase (EC 3.2.1.9) have been covalently bound in a two-enzyme system to a crosslinked copolymer of acrylarmide-acrylic acid by using a water-soluble carbodiimide. The coupling yields based on the amounts of added β-amylase and pullulanase were 40% and 38%, respectively, with residual enzymic activities of 22% and 32% of those of free enzymes. A markedly increased operational stability was observed for the immobilized two-enzyme system compared to the free enzymes in solution. In order to find optimal operational conditions the influence of different pH values and temperatures on the conversion process was investigated. The action of the immobilized β-amylase-pullulanase derivative on partially hydrolyzed starch (DE 3.4-10.7) in a packed bed column was studied. Analysis of the product was performed using gas-liquid chromatography.
    Additional Material: 7 Ill.
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  • 103
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 635-657 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Candida tropicalis was cultured in a chemostat-type fermentor with n-hexadecane, dispersed in water as submicron droplets, as the only carbon substrate. The emulsion as well as the aqueous medium were fed continuously into the fermentor. A Monod-type equation can correlate the specific group rate in the continuous fermentor with the concentration of submicron droplets. The same equation can also be fitted to the data for the conventional-type batch culture in the same fermentor in which an oil phase as well as an aqueous phase existed, if the hydrocarbon concentration in the aqueous phase excluding oil drops is employed as the substrate concentration. This demonstrates that Candida tropicalis takes up only submicron droplets of n-hexadecane as the carbon substrate.
    Additional Material: 10 Ill.
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  • 104
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 689-696 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A soluble fungal lactase (lactase-W) of greater activity that the previously available fungal lactase (lactase-M) has been covalently coupled to ZrO2-coated porous glass particles and 1 mm diameter porous TiO2 particles. The immobilized lactase-W appears to give results similar to the lactase-M except for the operational half-life. At 30°C the half-life of the lactase-M appears to exceed that of the lactase-W by approximately 100 days under operational conditions.
    Additional Material: 3 Ill.
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  • 105
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 739-755 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Humic substances were isolated during batch aeration studies with activated sludge and a complex waste source, by using concentration and separation techniques that employ reverse osmosis, ultrafitration, and gel permeation chromatography. The study suggests that the formation of high molecular weight humic substances may occur after the removal of the readily available carbon source. The amount of refractory material finally present in the solution will depend on its adsorptive properties toward bacterial cells. The adsorptive characteristics may be determined by the magnitude of the carbohydrate fraction present in the humic substances. If the carbohydrate content decreases, adsorption onto the cells may decrease resulting in an impairment of both the floe formation and settleability of the sludge floes. Decreased adsorption will result in a higher total organic carbon content and an increase in color bearing materials in the effluent.
    Additional Material: 6 Ill.
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  • 106
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 723-738 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Previous experimentation in our laboratory has shown that the classical theory developed for continuous growth of pure cultures in completely mixed aerobic systems in which the recycle cell concentration factor, c (where c = XR/X), is a selectable system constant, did not provide a suitable model for the heterogeneous (natural) populations of the activated sludge process. Another model was derived in which the recycle cell concentration, XR was employed as a system constant instead of c, and computational analysis was performed. Laboratory pilot plant experimentation was undertaken in order to determine whether a “steady state” in aerator biological solids concentration, X̄, and substrate concentration, S̄, could be approached under this mode of operation. Studies were performed at various organic feed concentrations holding dilution rate, D, at 0.125 hr-1, hydraulic recycle ratio, α, at 0.25, and XR at 10,000 mg/liter. Also, values of maximum specific growth rate, μmax, and saturation constant, Ks were determined. It was found that the model approached the steady state condition with heterogeneous populations more closely than did the classical model, and the high degree of treatment efficiency predicted by the model was demonstrated experimentally.
    Additional Material: 6 Ill.
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  • 107
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 108
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 909-923 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The intrusion of diffusion in heterogeneous enzyme reactions, which follow. Michaelis-Menten kinetics, is quantitatively characterized by dimensionless parameters that are independent of the substrate concentration. The effects of these parameters on the overall rate of reaction is illustrated on plots commonly employed in enzyme kinetics. The departure from Michaelis-Menten kinetics due to diffusion limitations can be best assessed by using Hofstee plots which are also suitable to distinguish between internal and external transport effects. A graphical method is described for the evaluation of the reaction rate as a function of the surface concentration of the substrate from measured data.
    Additional Material: 8 Ill.
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  • 109
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 987-990 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 110
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1004-1004 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
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  • 111
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1045-1053 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies exploring the effect of two nonaqueous solvents on enzyme activity were done using chloroperoxidase as a model system. Chloroperoxidase produced by Caldariomyces fumago is a bifunctional enzyme with halogenating activity at pH 3 and peroxidation activity at pH 5 to 6. Methanol affected both of these activities similarly. Furthermore, methanol and the halogen acceptor, monochlorodimedon, competitively inhibit the reaction. These results are discussed in terms of the site of action of methanol. At 10% methanol concentration, the enzyme retained up to 33% of its activity depending on the monochlorodimedon concentration. Dimethylsulfoxide at 10% concentration permitted up to 47% retention of activity. Its effects on the enzyme are more complex than methanol and are discussed in terms of a transitory inactivation of the enzyme.
    Additional Material: 3 Ill.
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  • 112
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1095-1102 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The enzyme tannase has been immobilized on an inorganic support by covalent attachment. This immobilized enzyme was characterized and half-lives determined. Since this enzyme has application in the treatment of tea cream, experiments were also carried out to determine the effect of tea on enzyme half-life.
    Additional Material: 5 Ill.
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  • 113
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1135-1137 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 114
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974) 
    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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  • 115
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 116
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1299-1320 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The overall rate of reaction of buffered gel-immobilized glucose oxidase particles is described by means of an enzyme rate equation which relates the overall reaction rate of a particle to the free solution characteristics of the enzyme, the effective diffusivity of the limiting substrate in the gel, the characteristic particle size, and the limiting substrate concentration adjacent to the gel surface. This equation accounts quantitatively for the limitation of the overall rate of reaction by substrate diffusion, and it is used to illustrate the influence of the system parameters, i. e., particle size, enzyme concentration, and pH, on the extent of the diffusional resistance associated with gel-immobilized glucose oxidase particles.The enzyme rate equation is generally applicable to those enzymes whose kinetics approximately follow Michaelis-Menten form when in free solution.
    Additional Material: 6 Ill.
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  • 117
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1373-1392 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The response of two-species commensalistic systems in a chemostat has been investigated after perturbations in steady state conditions and after step changes in dilution rate. The system is inherently stable with not more than three overshoots and undershoots possible. More complicated commensalistic systems are less stable, with limit cycle response occurring after dilution rate changes when feedback inhibition and feedforward activation occurs. In general variation of feedback parameters is more effective in changing the behavior of the systems than variation of feedforward parameters. Limited agreement with the experimental data of Chao and Reilly was obtained.
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  • 118
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1407-1411 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 119
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1425-1429 
    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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  • 120
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    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 16 (1974), S. 1471-1493 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Waste cellulose was a suitable carbon source for cellulose production by Trichoderma viride. The enzyme can be produced in submerged fermentation using newspaper as a growth substrate. A variety of pure and complex cellulosic materials were hydrolyzed by culture filtrates. Saccharification of 5% slurries after 48 hr ranged from 2-92%. The rate and extent of hydrolysis was controlled by degree of crystallinity, particle size, and presence of impurities. Newspaper was used to evaluate methods for the pretreatment of substrate. The best pretreatment was ball milling which gave good size reduction, maximum bulk density, and maximum susceptibility. Hammer milling, fluid energy milling, colloid milling, or alkali treatments were less satisfactory. Dissolving cellulose in cuprammonium, or carbon disulfide (Viscose) and then reprecipitating gave a susceptible, but low bulk density product. However the susceptibility was lost if the substrate was dried. Because of costs, low bulk density, necessity of keep ing the substrate wet, and generation of chemical waste streams dissolving cellulose to increase reactivity does not seem a practical approach.Cellulose fractions separated from municipal trash or agricultural residues such as milled fibres from bovine manure are promising substrates for conversion.
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  • 121
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    Biotechnology and Bioengineering 16 (1974), S. 1537-1544 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aminoacylase was covalently coupled to several porous ceramic type carriers and studied for durability under operating conditions. These studies indicate that it should be possible to develop a commercially economic system based on ceramic carriers for the resolution of racemic mixtures of amino acids.
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  • 122
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    Biotechnology and Bioengineering 16 (1974), S. 1553-1556 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
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  • 123
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    Biotechnology and Bioengineering 16 (1974), S. 1567-1587 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Kinetic studies on the parameters influencing the potential industrial application of an immobilized two-enzyme system of β-amylase and pullulanase for conversion of starch to a product with high maltose content, have been performed. The apparent Michaelis constant, the apparent product inhibitor constant, and the activation energy have been determined for the immobilized preparation and compared to the values for the corresponding soluble enzyme system. The catalytic activity of the immobilized enzymes was studied in a plug-flow reactor and a continuous feed stirred tank reactor. Mathematical models for these reactors have been formulated and adapted to fit the experimental data. Comparisons of the reactor efficiencies were made and the conditions were found to be such as to favor the plug-flow reactor. Results on operational stability tests at different temperatures and substrate concentrations are given.
    Additional Material: 17 Ill.
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  • 124
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The microbial cells of Pseudomonas putida ATCC 4359 were immobilized by entrapment in a polyacrylamide gel lattice. Enzymatic properties of L-arginine deiminase of the immobilized P. putida cells were investigated and compared with those of the intact cells. The permeability of substrate or product through the cell wall und the heat stability of the enzyme were increased by immobilization of the cells. No difference was observed between pH activity curves of the intact and immobilized cells. The optimal temperature for the formation of L-citrulline was 37°C for the intact cells and 55° C for the immobilized cells.When an aqueous solution of 0.5M L-arginine hydrochloride (pH 6.0) was passed through a column packed with the immobilized cells at a flow rate of SV = 0.26 at 37°C, L-arginine was completely converted to L-citrulline. The enzyme activity of the column was stable and the continuous production of L-citrulline could be carried out at 37°C for the month by using the immobilized cell column. From the effluent of the column, L-citrulline was easily obtained in a good yield.
    Additional Material: 7 Ill.
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  • 125
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Nitrifying characteristics were compared for an extended aeration (total cell recycle) process and one employing an engineering modification of the process utilizing a “hydrolytic assist” to aid biological autodigestion. Laboratory pilot plants were run over a period of years, and it was found that the recently recommended “hydrolytic assist” did not militate against production of a highly nitrified effluent. Under this mode of operation, the effluent was as nitrified as the effluent from the normal extended aeration process. It was also found that the modified process rapidly recovered its nitrifying capability after a period of deprivation of excess ammonia nitrogen. Throughout the period of operation, substrate removal efficiency remained high.
    Additional Material: 6 Ill.
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  • 126
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    Biotechnology and Bioengineering 16 (1974), S. 99-118 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A theoretical treatment is given of the kinetics of reactions catalyzed by enzymes attached to the inner surface of a tube, through which the substrate solution passes. A utilization factor, the ratio of the actual reaction rate to that in the absence of diffusional effects, is defined. A numerical procedure is proposed and numerical and approximate solutions for the utilization factor are given for five kinetic conditions: (a) Michaelis-Menten behavior, (b) substrate inhibition, (c) product inhibition (competitive), (d) product, inhibition (non-competitive), and (e) product inhibition (anticompetitive). When the enzyme chemically attached to a tube obeys a Michaelis-Menten relationship, criteria for insignificant and significant diffusional effects are proposed.
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  • 127
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    Biotechnology and Bioengineering 16 (1974) 
    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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  • 128
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    Biotechnology and Bioengineering 16 (1974), S. 361-369 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Hen's egg white lysozyme (EC 3.2.1.17) has been covalently attached to a polystyrene matrix via interaction of protein nucleophiles with an aromatic imidazolide function under anhydrous conditions. The polymer-enzyme complex is prepared in a way which allows nonaqueous solubilization of the complex. The activity of the bound enzyme compares favorably with the activity of the native protein. The pH optima for the matrix-supported protein are shifted toward the basic side. The effect of substrate concentration on rate has been determined. (A preliminary report of this work has been published: G. J. Bartling, H. D. Brown, S. K. Chattopadhyay, Nature 243, 342-344 (1973).)
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  • 129
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    Biotechnology and Bioengineering 16 (1974), S. 413-417 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 130
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    Biotechnology and Bioengineering 16 (1974), S. 295-313 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The enzyme β-galactosidase (lactose) obtained from several microbial sources was immobilized on zirconia-coated porous glass particles. The immobilized enzymes were characterized by determining pH profiles, kinetic constants, thermal profiles, and operationalhalf-lives in lactose and whey ultrafiltrate solutions. Studies were carried out on continuous reactor performance, and enzyme requirements for scale-up were estimated. Lactose or whey hydrolyzed by this technique could find use commercially as a sweetener in a number of dairy products.
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  • 131
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    Biotechnology and Bioengineering 16 (1974), S. 315-332 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetic behavior of water insoluble enzyme columns was studied using the hydrolysis of GPNA (N-glutaryl-L-phenylalanine-p-nitroanilide) by α-chymotrypsin as a model. Thermal denaturation of soluble and insoluble enzyme was compared in a batch reactor and in a tubular reactor. Convection of metabolites, enzyme reaction, diffusion of metabolites across porous particles and the kinetic behavior of a water insoluble enzyme column were tested.The respective and mutual effects of the first two phenomena were comprehensively analyzed for both stationary state and transient conditions. When the ingoing substrate concentration was varying with time, convection-reaction equations were solved by digital computation. The possible effects of diffusion limitations and unstirred layers are discussed.
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  • 132
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    Biotechnology and Bioengineering 16 (1974), S. 455-474 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Changes in the catabolic pattern of Saccharomyces cerevisiae, growing in continuous culture, were effected by altering the glucose feed rate or the dissolved oxygen concentration. The cytochrome concentrations and the adenosine phosphate pool level of the yeast in a series of steady states and during three transitions were measured and compared with the glucose uptake rate (QG), the respiration rate (QO2), and the rate of ethanolic fermentation (QE).Respiration was decreased at high glucose feed rates only if oxygen was low but cytochromes were glucose repressible at both high and low oxygen concentrations. In the main, QE and the levels of ATP, ADP, and AMP were decreased and cytochrome concentration were elevated at low QG values. No consistent relationship between any of the adenosine phosphate parameters and QO2 was discernible.Evidence is presented for the concept that the QG directly controls the adenosine phosphate pool level and that a relationship between the concentration of adenosine phosphate anhydride bonds and the adenosine phosphate level is constantly maintained.
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  • 133
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    Biotechnology and Bioengineering 16 (1974) 
    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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  • 134
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    Biotechnology and Bioengineering 16 (1974), S. 827-846 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The temperature-dependent endogenous metabolism model of single species continuous culture dynamics is utilized in the computer simulation of the Kalman filter state estimation technique. Parameters of the nonlinear equations can be “tracked” while variance in measured states can be damped. The state estimator is illustrated in, the context of conventional control strategies.
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  • 135
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    Biotechnology and Bioengineering 16 (1974), S. 897-908 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The immobilization of glucose oxidase and catalase by adsorption within the pores of controlled-pore titania has yielded a remarkably stable enzyme system. Catalase apparently acts as both a stabilizer and an activator for glucose oxidase within the pores of this material. Hydrogen peroxide concentrations and flow rates have a marked effect upon the apparent activity of the immobilized enzyme system. The carrier parameters were varied to obtain optimum loading and stability information.
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  • 136
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    Biotechnology and Bioengineering 16 (1974), S. 943-963 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: β-galactosidase from E. coli (β-D-galactose galactohydrolase, EC 3.2.1.23) has been entrapped in a crosslinked 2-hydroxyethyl methacrylate gel with a 35% retention of activity. The kinetic behavior of the gel-entrapped enzyme has been studied in a recirculation reactor system, the substrate being o-nitrophenyl-βhyphen;D- galactopyranoside. Kinetic constants were determined for particle sizes ranging from 69 to 231 μm in diameter and compared to those of the free enzyme. External diffusion effects were eliminated by operating at high recirculation flow rates. A fourfold increase in Km(app) was observed for the 231 μm particles, consistent with existing theoretical treatments for internal diffusion effects.An Arrhenius plot of rate data showed significant curvature at higher temperatures, which was attributed to the effects of internal diffusion. The pH-activity profile of the gel-entrapped enzyme was bell-shaped at high substrate concentration and, in contrast to the free enzyme, could be fitted to the titration curve of two ionizable groups, a basic group having a pK of 8.6. The gel-entrapped enzyme had a higher pH optimum and retained a larger percentage of its maximal activity at alkaline pH than the free enzyme; its pH stability at high pH was also much better.The thermal stability of the gel-entrapped enzyme was studied and found to be 14 days at 22°C and 65 min at 45°C.
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  • 137
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    Biotechnology and Bioengineering 16 (1974), S. 933-941 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Oxygen supply is one of the main factors which influences aerobic cell growth in a fermentor. Maximal rates at which E. coli can grow on glucose as carbon source under various limiting oxygen-supply conditions were determined in a bench-scale fermentor. Culture conditions are described which gave yields of about 38 g dry cells per liter medium.
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  • 138
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    Biotechnology and Bioengineering 16 (1974), S. 991-995 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 139
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    Biotechnology and Bioengineering 16 (1974) 
    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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  • 140
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    Biotechnology and Bioengineering 16 (1974), S. 1345-1357 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Many enzyme-catalyzed reactions involve the liberation or consumption of hydrogen ions. In this paper a mathematical model is employed to investigate how such reactions behave when the enzyme is immobilized. Shifted pH optima, disappearance of an optimum pH, insensitivity to bulk pH, and very large effectiveness factors are some of the phenomena which appear as a result of pH coupling between the reaction and the enzyme's activity. Several of the qualitative features revealed by the model are consistent with earlier experimental observations. In addition, preliminary guidelines for optimal choice of enzyme support are suggested.
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  • 141
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    Biotechnology and Bioengineering 16 (1974), S. 1393-1398 
    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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  • 142
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    Biotechnology and Bioengineering 16 (1974), S. 1419-1423 
    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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  • 143
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    Biotechnology and Bioengineering 16 (1974), S. 1449-1458 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The enzymatic synthesis of nucleoside-5′-monophosphates from purineriboside, 6-mercapto-purine riboside, 6-methylmercapto-purine riboside, 6-chloro-purine riboside, tubercidin, 8-aza-adenosine, and 3′-deoxy-adenosine is described in gram scale. The synthesis is catalyzed by a phosphotransferase from carrots and uses phenylphosphate as phosphate donor. The reaction products are purified on QAE-Sephadex A25 columns. The large scale preparation of the enzyme is also reported.
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  • 144
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Partially purified lactoses (β-D-galactoside galactohydrolase, EC 3.2.1.23) from Aspergillus niger, Ladobacillus helveticus, and Saccharomyces lactis were immobilized on diazotized porous glass particles (mean pore diameter, 86.5 nm: particle size diameters, 75-125 μm). In acid whey containing 4-4.5% lactose, A. niger lactase gave the highest activity (89 μmoles lactose hydrolyzed/g glass, min) at 55°C and pH 4.5. Glass-immobilized A. niger laclases (lactase-BG) retained much hydrolytic activity after storage and periodic use for 165 days at 55°C. For values of X greater than 30%, hydrolysis of 0.12M lactose in acid whey by a continuous flow column packed with 2 ml of lactase-BG particles could be correlated by X = 17.2(V/F) + 12.5 where X = lactose hydrolysis, percent of lactose originally present; V = volume of packed bed of lactase-BG, ml; F = flow rate of acid whey, ml/min.
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  • 145
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    Biotechnology and Bioengineering 16 (1974) 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 146
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    Biotechnology and Bioengineering 16 (1974), S. 423-427 
    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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  • 147
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In an effort, to develop comprehensive mathematical models for use in optimizing fermentation processes, product rate data taken at constant pH's for the lactic acid fermentation (Lactobacillus delbrueckii) were analyzed. It was observed that the rate of acid synthesis-time trajectories exhibited a “shoulder” effect at pH's less than 5. That is, a nearly constant rate of synthesis for up to 10 hr in the late growth phase, out of a maximum total fermentation time of 70 hr. This effect was used as a clue from which to structure the proposed model with parallel pathways. Simulating shunting pathways does, in fact, demonstrate that, the notion of parallelism is consistent with the expression of a shoulder. It is postulated, therefore, that a differential pH effect between two parallel pathways can account for the presence of a shoulder when both routes prevail, and no shoulder when either pathway predominates.
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  • 148
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    Biotechnology and Bioengineering 16 (1974), S. 623-634 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Maltase, phosphatase, malate dehydrogenase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase activities were determined in the supernatant of brewer's yeast cells from samples taken at various intervals during a 90 min treatment in a Dyno-Mill disintegrator.In an attempt to find optimum operating conditions, the following parameters were varied: speed of rotation of the agitator, flow rate, yeast concentration in the slurry and bead diameter, and the specific rate of extraction was determined for each such variation. Analysis of the data showed that, superimposed upon extraction, there was a progressive but slow loss of total activities. Enzyme release could be expressed as an approximately first-order chemical reaction. The results compared well with those of Follows et al. (Biotechnol. Bioeng.), 13, 549 (1971) and showed that the Dyno-Mill can be operated under proper conditions without significant loss of enzyme activity and with high yields.
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  • 149
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    Biotechnology and Bioengineering 16 (1974), S. 697-699 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 150
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    Biotechnology and Bioengineering 16 (1974), S. 703-722 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The complete mixing activated sludge (CMAS) system is gaining in popularity for treating both domestic and industrial wastewaters. Experience over the past 20 years has produced a simple mathematical model which can be used in both the design and the operational evaluation of CMAS systems. Laboratory pilot plants and full scale field units have furnished the basic data needed to confirm the validity of the mathematical model. The basic concepts of the model are discussed in light of field evaluations. Areas of conflict and confusion which have arisen in the past will be presented and discussed. Design examples and operational evaluations are presented for several different wastewater systems.
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  • 151
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    Biotechnology and Bioengineering 16 (1974), S. 771-787 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Anaerobic fermentation of organic solid waste can provide a significant source of fuel gas (methane). Application of this process requires a better understanding of the kinetics of the biological system. The literature is replete with kinetic studies of this process as applied to waste solids from water pollution control systems. Much of this work has been conducted in the mesophilic temperature range. Increased temperatures yield higher reaction rates that will improve the economics of the process. The rate limiting step in the fermentation of refuse is the hydrolysis of the complex organic solids, in particular cellulose. Cellulose is a major component of the refuse. A laboratory study employing domestic refuse has shown the effect of temperature on the rate of methane fermentation. The optimum mesophilic temperature was found to be 42°C, while the optimum thermophilic temperature was at least 60°C. No data was obtained beyond the 60°C temperature. Reaction rate constants are presented for anaerobic fermentation of domestic refuse. Because of the characteristics of the substrate it-was not possible to obtain the necessary measurements for evaluation of constants in the Monod model. An overall system constant was developed.
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  • 152
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    Biotechnology and Bioengineering 16 (1974), S. 847-851 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bacterial RNA virus, Qβ, has been purified in gram amounts by differential centrifugation. Final separation of the virus from host E. coli rRNA was based on the density differential in the pellet. The method provided a simplified alternative to the more conventional rate zonal or isopycnic zonal centrifugation techniques.
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  • 153
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    Biotechnology and Bioengineering 16 (1974), S. 853-858 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
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  • 154
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    Biotechnology and Bioengineering 16 (1974), S. 869-880 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Conventional sources of protein cannot meet the present or projected needs for human consumption. Single cell proteins from fermentation of petroleum and cellulosic wastes are likely sources of additional protein. The volume of cellulosic wastes is sufficient to supply all additional protein needs on a continuing basis for cellulose is a renewable resource. Both mesophilic and thermophilic microorganisms utilize cellulose at reasonable rates. Biodegradation of lignin and lignin-cellulose complexes constitutes a major obstacle to commercial utilization of cellulosic wastes. Thermophilic actinomyces appear to be the most effective organisms for single cell protein production from cellulosic wastes.
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  • 155
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    Biotechnology and Bioengineering 16 (1974), S. 925-931 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: NAD was covalently linked to Sepharose-4B using a 6 carbon spacer. Sterile, dialyzed spent culture medium containing 100 Lf/ml of diphtheria toxin or material concentrated by (NH4)2SO4 precipitation containing 1500 Lf/ml, was chromatographed on a column of NAD-Sepharose. Ultraviolet absorbing material which did not flocculate with diphtheria antitoxin was eluted with 0.02M phosphate buffer. When the elation buffer was changed to one containing 0.5M NaCl, purified toxin was eluted off the column.
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  • 156
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    Biotechnology and Bioengineering 16 (1974), S. 965-985 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The yeast Candida tropicalis utilizes both glucose and hydrocarbons as sole carbon sources. When grown on hydrocarbons, the cells contain twice as much lipid as when grown on glucose. In transient continuous culture experiments, following a substrate change from glucose to hexadecane, an adaption phase occurred. During this phase the lipid concentration per cell increased greatly. It is proposed that a high cellular lipid concentration is necessary for hydrocarbon assimilation, and this is not just a reflection of the lipophilic nature of the substrate.
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  • 157
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    Biotechnology and Bioengineering 16 (1974), S. 1005-1013 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Information is presented concerning revisions of the fermentation air system equipment which improved the sterility situation in the production of monosodium glutamate.Basically, the revision were a relocation and elevation of the intake to the air compressors and installation of a retention chamber after the compressors to take advantage of the heat of compression.The extended high temperature retention ensures sterile air to the final air filter before the fermentor. Contamination losses - mainly from phage - have been materially reduced relative to the level prevailing before the change.
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  • 158
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    Biotechnology and Bioengineering 16 (1974), S. 1069-1079 
    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 is described for the large-scale preparation of erythropoietin from anemic sheep plasma. DEAE-cellulose and carboxymethylcellulose column chromatography was used to prepare Step II erythropoietin. A total of 168 sheep yielded 499 liters of plasma from which 323,000 IU of Step II erythropoietin was obtained.
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  • 159
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    Biotechnology and Bioengineering 16 (1974), S. 1197-1212 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Efforts were made to eliminate the influence of other factors as far as possible in order to obtain reliable results on the effects of oxygen on the growth of baker's yeast. A cultivation method is presented which permits the study of the effects of aeration intensity under conditions where the influence of catabolite repression is eliminated. A completely synthetic medium with glucose as the only carbon and energy source is also described.The capacity of yeast to perform aerobic metabolism varies when cultivated under different intensities of aeration. A clear maximum is observed for growth with 10% oxygen in the aerating gas mixture. Under conditions where catabolite repression does not function yeast has the potential for oxidative metabolism even under oxygen-limited growth. The main agent controlling the ability of yeast to support growth using only the oxidative metabolism is the available oxygen.At high oxygen tensions the metabolism is disturbed.
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  • 160
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    Biotechnology and Bioengineering 16 (1974), S. 1227-1243 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An intracellular, thermostable, neutral α-galactosidase (α-D-galactoside galactohydrolase EC 3.2.1.32) was produced in pilot plant quantities from a strain of Bacillus stearothermophilus. The organism was cultured at 50°C in a soluble neutral medium containing water extract of soybean meal (3%) and 0.5% yeast extract. The enzyme biosynthesis was inducible and sensitive to catabolite repression. After autolysis of the cells, the α-galactosidase was selectively and quantitatively complexed from clarified beer directly onto DEAE Sephadex; and enzyme-rich fractions were batchwise eluted with an increasing gradient of NaCl solutions. The eluates were given two consecutive isopropyl alcohol precipitations, and the aqueous solutions of the second precipitate were dialyzed and lyophilized. Final product activity recovery was 72% based on the crude fermentation beer. Best specific activity was 5.2 u/mg protein. Further laboratory purification (DEAE Sephadex and Bio-Gel P200) yielded a product with 14.2 u/mg protein.
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  • 161
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    Biotechnology and Bioengineering 16 (1974), S. 1245-1259 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The death kinetics of a strain of Saccharomyces cerevisiae were studied in an industrial scale spray drier. In solution studies, the death kinetics of yeast was found to be comparable to pathogen destruction. From the studies in drying of yeast a prediction of a 4 log cycle decrease in viable cells of pathogens could be made for normal processing conditions. This should insure the safety of spray-dried foods unless after contamination occurs. It was found that during drying, although the rate of death is high, the activation energy is greatly decreased over that of death in aqueous solution (reduction from 130 kcal/mole to 5 kcal/mole). The reduction in Ea may be attributed to the thermodynamic compensation phenomenon in which the resulting negative entropy of reaction acts to protect the cells through a water-protein interaction. However, the possibility of a change in death mechanism cannot be precluded. Overall, these results suggest the danger in extrapolating death kinetics to high temperature.
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  • 162
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    Biotechnology and Bioengineering 16 (1974), S. 1321-1343 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The overall rate of reaction of gel-immobilized glucose oxidase particles in buffered media has been investigated theoretically under two substrate diffusion limited conditions by the numerical solution of the diffusion equations. It has been found that the Enzyme Rate Equation (Atkinson and Lester), Biotechnol. Bioeng., 16, 1299 (1974), together with an analytical solution which describes the asymptotic conditions associated with a large particle size, provides an adequate estimation of the values resulting from the numerical solution outside the region of the parameter space defined by 0.4 〈 Mg′, M0′ 〈 10.When the dimensionless parameter (B0′/Bg′)(Mg′2/M0′2) is greater than unity the overall rate of reaction is limited principally by the external concentration and when the parameter has a value less than unity, by the external oxygen concentration.The results are generally applicable to enzymes whose kinetics are similar to those of glucose oxidase or for which the equation describing glucose oxidase kinetics provides an adequate curve-fit of experimental data.
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  • 163
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    Biotechnology and Bioengineering 16 (1974), S. 1399-1406 
    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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  • 164
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    Biotechnology and Bioengineering 16 (1974) 
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    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 165
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    Biotechnology and Bioengineering 16 (1974), S. 1459-1469 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An apparatus is described for the rapid measurement and recording of methanogenic activity in anaerobic fermentations, and its application is demonstrated in the evaluation of the anaerobic contact process, using pear waste. The method is based on recording the rate of manometer liquid displacement in a Warburgtype vessel by means of optical sensors, appropriate electronic circuitry, and an event marking recorder or time-interval printer. Optimum conditions for measuring methanogenic activity included a pH of 6.7-6.9, a final phosphate buffer concentration of 0.07-015M, and formic and acetic acid contents of over 500 and 200 mg/liter, respectively. In comparisons of fermenter liquid and settled effluent, methanogenic activity can be assumed to be proportional to the number of methane formers present. The apparatus should be generally useful in recording rates of gas production or consumption.
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  • 166
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    Biotechnology and Bioengineering 16 (1974), S. 1517-1528 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Immobilized glucoamylase, invertase, and β-galactosidase were prepared by using N-vinylpyrrolidone monomer (VP) under γ-ray irradiation. The enzyme-VP solutions were gelled by irradiation with 2.9 Mrad and the added enzymes were almost completely entrapped. Activity losses on entrapping were 55% for the VP-glucoamylase gel, and more than 90% in the case of VP-invertase and VP-β-galactosidase gels. No leakage of enzyme from these gels could be detected within 1 hr. The VP-glucoamylase gel was capable of hydrolyzing dextrin (mol wt 10,400) to glucose and the glucose equivalent was equal to that obtain able with native enzyme. The optimum temperature, heat stability, pH activity curve, and pH stability of VP-glucoamylase gel were slightly inferior to those of native enzyme, while Km was a little larger than that of native enzyme.
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  • 167
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    Biotechnology and Bioengineering 16 (1974), S. 1549-1551 
    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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  • 168
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    Biotechnology and Bioengineering 16 (1974) 
    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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  • 169
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    Biotechnology and Bioengineering 16 (1974), S. 1633-1644 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The β-galactosidase from Escherichia coli ATTCC-26 was partially purified and characterized. It was found to be comparable to galactosidases from other E. coli strains in stability, pH and temperature maxima, and activity requirements, but it had a more favorable ratio of activity toward lactose versus synthetic substrates. The galactosidase was immobilized on porous glass beads by three covalent bonding methods. Kinetic data for the free and bound enzymes were determined using natural and synthetic substrates. Activity characteristics of the free and immobilized enzymes were comparable, however, the bound forms were less stable to heat.
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  • 170
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    Biotechnology and Bioengineering 16 (1974), S. 1659-1673 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Immobilized beef liver catalase has been used in a flow reactor to decompose hydrogen peroxide; at the same time the catalase is inactivated by its substrate. A model has been developed which predicts this rate of decomposition of peroxide and inactivation of catalase. First order dependence on peroxide concentration is assumed. The model was verified by experiment for a range of operating conditions and then used to predict the effects of a change in operating variables.
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  • 171
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    Biotechnology and Bioengineering 16 (1974), S. i 
    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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  • 172
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    Biotechnology and Bioengineering 16 (1974), S. 61-76 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Polysaccharide was synthesized by Aureobasidium pullulans (or Pullularia pullulans) 2552 in a sucrose medium. The field apparent viscosity of the culture medium from shake flask experiments rose to 24,500 cP and then dropped toward its initial value as the fermentation progressed. The magnitude of the maximum apparent viscosity depended on the initial pH of the fermentation broth. The inoculum age influenced the cultivation period before which the maximum viscosity was reached. Rheograms of the fermentation broths showed a change in viscosity behavior from Newtonian to pseudoplastic, and then toward Newtonian characteristics during the fermentation. The calculated non-Newtonian index was found to be a sensitive factor for the indication of the non-Newtonian behavior. Such behavior could not be detected from rheograms. Viscosity profiles of polysaccharide isolated from various stages of the fermentation showed a change from Newtonian to pseudoplastic behavior depending on the concentration (0-2%) of polysaccharide.
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  • 173
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    Biotechnology and Bioengineering 16 (1974), S. 181-208 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An experimental investigation on the rheology of penicillin broths was undertaken in order to obtain more understanding of this important aspect of the fermentation process. The measuring technique consisted in observation of the torque exerted upon a rotating turbine impeller. The experimental data were interpreted in terms of a model which basically is a synthesis of a known relationship for the rheological behavior of printing ink (Casson equation) and some considerations analogous to the rheological description of polymer solutions (excluded volume concept). One of the key variables in the model is a morphology factor, which can be used for a quantitative description of mycelial morphology. The value of the morphology factor can be determined experimentally by a simple viscosity measurement in combination with a mycelial dry weight determination. There are strong indications that the model may be applicable to mycelial broths other than those of penicillin.
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  • 174
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    Biotechnology and Bioengineering 16 (1974), S. 169-179 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The utility of an immobilized enzyme depends not only on initial loading but also on operational half-life. The loss of activity of an immobilized enzyme in a column reactor may occur in several ways. It is therefore of interest to determine whether the decay in activity is due to the rupture of any of the enzyme-carrier bonds in the composite. In order to do this, it is first necessary to establish whether the enzyme on the composite is in fact covalently bound or adsorbed. In this report we have shown that there are a number of covalent links per protein molecule. We have also shown that the bond energies are sufficient to prevent shearing of the enzyme itself from the composite under any stresses which may occur in a chromatography column or packed-bed reactor during continuous operation. The effect of the siloxane linkage on composite stability is also discussed.
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  • 175
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    Biotechnology and Bioengineering 16 (1974), S. 475-484 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A fiber-optic retroreflective turbidimeter has been developed to automatically and continuously assay the cell concentration in a fermentor by measuring the turbidity of the solution as a function of the light scattered at 180° to the incident light. The output signal is nearly directly proportional to the cell concentration in a fermentor when the sample stream contains from 0 to more than 50 g of cells per liter (wet weight). The device consists of a bifurcated fiber-optics light pipe with its distal end inserted into a flow cell through which the material to be analyzed passes. A light source on one proximal branch of the light pipe illuminates the sample stream; light that is back-scattered from participates in the stream re-enters the light pipe and is returned to a photodetector on the other proximal branch of the light pipe. A signal conditioning system connected to the optical head by a cable provides gain and zero adjustment.
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  • 176
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    Biotechnology and Bioengineering 16 (1974), S. 513-523 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Purified enzymes encapsulated in liquid surfactant membranes have been shown to retain their catalytic activity. In general, previous work on encapsulation has been confined to single enzymes. The system has now been extended to encapsulate a bacterial cell-free homogenate. Liquid membrane-encapsulated bacterial cell-free homogenate reduces effectively NO3- to NO2- and other nitrogen compounds of lower oxidation state. This technique of removing nitrates and nitrites may have application in waste-water treatment. Also, it has been shown that encapsulated cell-free homogenate does not leak and there is no absorption of the substrate onto the liquid surfactant membrane surfaces. The reduction in the reaction rates is discussed in terms of solubility of the substrate and the rate of permeation of the substrates through the liquid surfactant membrane.
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  • 177
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    Biotechnology and Bioengineering 16 (1974), S. 531-538 
    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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  • 178
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    Journal of Cellular Physiology 83 (1974), S. 27-34 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The relationship between alkaline phosphatase activity and cell growth has been studied in hamster cells transformed by different carcinogens. About 90% of normal hamster embryo cells were constitutively positive for alkaline phosphatase activity (AP+). However, there were no AP+ cells in cell lines transformed after treatment with the chemical carcinogens dimethylnitrosamine or 4-nitro-quinoline-N-oxide and 0.02% and 4% AP+ cells in cell lines transformed by polyoma virus or Simian virus 40. The glucocorticoid hormone, prednisolone, induced alkaline phosphatase activity in 12% and 44% of the enzyme-negative (AP-) cells in cell lines transformed by polyoma or Simian virus 40, but this hormone did not induce alkaline phosphatase activity in AP- cells from cell lines transformed after treatment with the chemical carcinogens. Treatment of polyoma transformed AP- cells with the mutagen N-methyl-N′-nitro-N-nitro-soguanidine produced AP+ cells, whereas no AP+ cells were found after mutagen treatment of AP- cells from the chemically transformed cell lines. Studies on spontaneous segregation in the polyoma transformed cell line has shown that AP+ cells segregated AP- cells both in vitro and in vivo, although no spontaneous segregation was observed from AP- to AP+ cells.AP+ cells, compared to AP- cells, showed a decrease in DNA synthesis, cell multiplication, the ability to form colonies in soft agar and tumorogenicity in animals. AP- cells induced for alkaline phosphatase activity by prednisolone, showed the same growth properties in vitro as uninduced AP- cells. The decreased cell growth found in AP+ cells which were constitutive for alkaline phosphatase activity was therefore not found in the hormone induced AP- cells. The results indicate that constitutive alkaline phosphatase activity appears to be related to the regulation of cell growth and that AP- cells have a selective advantage over AP+ cells.
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  • 179
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: The pattern of changing activities of three lysosomal enzymes, N-acetyl-β-D-glucosaminidase, aryl sulfatase, and DNase II, and that of DNA polymerase was followed in homogenates of 3T3 cells during the logarithmic phase of growth and in stationary cultures. The change in activities of the polymerase and the lysosomal enzymes is antiparallel. DNA polymerase exhibits highest activity in growing cultures, and shows a three-fold decline of the specific activity in stationary cultures. The lysosomal enzymes show a very marked increase in their specific activity after density saturation is reached, which can be prevented by the addition of cycloheximide. Colcemid added to logarithmically growing cultures also causes an increase in the specific activities of lysosomal enzymes.
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  • 180
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    Journal of Cellular Physiology 83 (1974), S. 219-230 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A series of Chinese hamster cell lines were tested and found to be able to proliferate in the absence of added bicarbonate and carbondioxide if hypoxanthine and uridine were present in the medium. Conversely, cells incapable of salvaging one of these precursors, such as hypoxanthine-guanine phosphoribosyltransferase (HGPRT-) deficient cells did not multiply under these conditions.We describe another variant capable of utilizing hypoxanthine and uridine which has an absolute requirement for exogenous CO2/NaHCO3 for growth. These cells appear to be defective in the complete oxidation of pyruvate to carbondioxide, and indications are that the entry of pyruvate into the Krebs cycle is affected.
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  • 181
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    Journal of Cellular Physiology 83 (1974), S. 287-296 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Elevated calcium and magnesium concentrations promoted mitotic activity in rat thymic lymphocyte cultures. Oestradiol inhibited calcium- but not magnesium-induced mitogenesis. One prerequisite for the mitogenic action of calcium is a raised intracellular concentration of cyclic adenosine 3′5′ monophosphate (cyclic AMP) but cyclic AMP-induced mitogenesis was insensitive to oestradiol. This suggests that the steroid blocks the mitogenic process at a stage preceding the endogenous cyclic AMP elevation. Furthermore the mitogenic actions of adrenaline, which stimulates adenylate cyclase (the enzyme responsible for cyclic AMP biosynthesis), and caffeine, which inhibits phosphodiesterase (the enzyme which degrades cyclic AMP) were also insensitive to oestradiol inhibition. This precludes a direct effect of the steroid on these enzymes. However, oestradiol did inhibit the mitogenic action of parathyroid hormone (PTH). Since the mitogenic action of PTH probably involves increased calcium entry to the cell, oestradiol may block this ion influx.The inhibition of calcium- and PTH-induced mitogenesis must be attributable to some structurally specific action of oestradiol. The steroids cholesterol, progesterone and testosterone all failed to reduce calcium-induced mitogenesis, whereas both α and β oestradiol were effective.In addition to its insensitivity to oestradiol inhibition, magnesium-stimulated mitosis was unaffected by both imidazole and calcitonin at concentrations which significantly reduced calcium-stimulated proliferation. These findings are compatible with the thesis that magnesium-induced mitogenesis does not involve the elevation of cyclic AMP concentrations.
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  • 182
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    Journal of Cellular Physiology 83 (1974), S. 337-343 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The transport of various deoxyribonucleosides by cultured Novikoff rat hepatoma cells (subline N1S1-67) follows normal Michaelis-Menten kinetics. The transport reactions are competitively inhibited by most heterologous deoxy- and ribonucleosides and by Persantin and Cytochalasin B. Comparisons of the transport kinetics of the various deoxyribonucleosides (Km and Vmax ) and of the Km/Ki ratios for the inhibitions indicate that deoxythymidine, deoxyuridine and 5-fluordeoxyuridine are transported by a single system, whereas deoxycytidine and the purine deoxyribonucleosides are transported by other systems. The data suggest that deoxyadenosine, deoxyguanosine and deoxyinosine, are not transported by a single system, but the number of transport systems involved could not be established unequivocally. Similar comparisons also suggest that the deoxyribonucleosides are transported by different systems than the ribonucleosides. All deoxyribonucleoside transport systems are inhibited to about the same extent by Persantin (Ki = 1-2 μM) and Cytochalasin B (Ki = 4-12 μM). The inhibitions of deoxynucleoside transport resulted in corresponding apparent competitive inhibitions of their incorporation into nucleic acids.
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  • 183
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    Journal of Cellular Physiology 83 (1974), S. 321-336 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The incorporation of 3H-labeled deoxyadenosine and deoxyguanosine into nucleic acids by cultured Novikoff rat hepatoma cells is about 80% into RNA and 20% into DNA. The pathways of incorporation have been elucidated in studies with whole cells and cell-free extracts. Deoxyadenosine is very rapidly deaminated to deoxyinosine. Most of the deoxyinosine formed by whole cells is transported out of the cells and accumulates in the medium. A portion of the deoxyinosine, and deoxyguanosine are phosphorolyzed by purine nucleoside phosphorylase to hypoxanthine and guanine, respectively. The latter are subsequently converted by hypoxanthine-guanine phosphoribosyl transferase to IMP and GMP, respectively. Incorporation of the purine deoxyribonucleosides into DNA is mainly via this pathway and the subsequent reduction of ADP and GDP by ribonucleoside reductase, although a small proportion of the deoxyadenosine and deoxyguanosine taken up by the cells seems to be directly phosphorylated to dAMP and dGMP, respectively. Deoxyguanosine is incorporated only into guanine residues of RNA and DNA. Deoxyadenosine is also mainly incorporated into guanine residues of RNA and DNA, although the radioactivity of deoxyadenosine in the acid-soluble pool is almost exclusively associated with ATP. A similar labeling pattern is observed with labeled deoxyinosine, inosine or hypoxanthine. The pyrimidine deoxyribonucleosides, on the other hand, are specific precursors for their respective bases in DNA.Hydroxyurea inhibits the incorporation of all deoxyribonucleosides into DNA. Results from pulse-chase experiments indicate that the inhibition of DNA synthesis is prevented by the presence of high concentrations of deoxyadenosine plus deoxyguanosine in the medium. Either purine deoxyribonucleoside alone or deoxycytidine, hypoxanthine or inosine alone or in combination with deoxyadenosine or deoxyguanosine are ineffective. The results are consistent with the conclusion that the inhibition of DNA synthesis is due to a depletion of the dATP and dGTP pools as a result of the hydroxyurea treatment. On the other hand, hydroxyurea causes an increased incorporation of thymidine and deoxycytidine into the dTTP and dCTP pools, respectively. Evidence is presented to indicate that this effect of hydroxyurea is due to an increased synthesis of dTTP and dCTP rather than to an inhibition of their turnover.
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  • 184
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    Journal of Cellular Physiology 83 (1974), S. 353-357 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: HTC cells incubated in the absence of serum for more than 14 hours have very low levels of ornithine decarboxylase, the first enzyme on the pathway of polyamine synthesis. Readdition of serum causes an increase in the activity of ODC, reaching a maximum on average 17 times above the basal level after five hours. This increase is due in part to a decrease in the apparent rate of degradation of ODC, and also to a stimulation of its synthesis. Within the first two hours the serum induction of ODC is resistant to Actinomycin D. Insulin at 5 μm/ml alsocauses an increase in ODC activity but only after a delay of two hours, in contrast to its more rapid stimulation of tyrosine transaminase activity.
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  • 185
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    Journal of Cellular Physiology 83 (1974), S. 243-250 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Net fluxes of sodium and potassium were studied in Ehrlich mouse ascites tumor cells during contact with the agglutinating protein, concanavalin A. This lectin altered cation transport markedly at concentrations of 20-105 μg/ml (6-47 μg/mg cell protein). Whereas control cells extruded sodium and maintained or accumulated potassium against electrochemical gradients, in the presence of concanavalin A there was rapid net sodium entry and potassium loss. After 10-20 minutes in concanavalin A, sodium extrusion began and potassium loss diminished but these events were prevented by ouabain. The alterations in cation content induced by concanavalin A are unlikely to be the result only of agglutination since soybean agglutinin caused much smaller changes although it agglutinated the cells equally well.
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  • 186
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    Journal of Cellular Physiology 83 (1974), S. 203-210 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effect of cell density on morphological transformation of chick embryo cells by Rous Sarcoma Virus (RSV) was examined in this study, and a cell density optimum for transformation was found. Less than 10% of the transformed foci appearing at the optimum density (2.5 × 104 cells per cm2) developed at high cell densities, and the diameters of the foci (an indication of the number of cells per focus) decreased with increasing cell density. No correlation was found between the decrease in transformation at high cell densities and the effect of cell density on the initial rate of cell proliferation, although dissociation of transformation from incorporation of radioactive precursors into nucleic acids could not be established. Redistribution of cells infected at high density showed that only a small proportion of successfully infected cells developed into foci. The results indicate that transformation of cells containing the RSV genome can be suppressed by physiological factors accompanying high cell density.
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  • 187
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    Journal of Cellular Physiology 84 (1974), S. 115-125 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ehrlich cells subjected to anisoosmolar media show very rapid volume changes. In hypertonic media they shrink. In hypotonic media they swell but the rapid initial swelling is followed by a regulatory shrinkage lasting ca. 30 minutes.Cells suspended in media with identical ionic concentrations but different total osmolarity (adjusted by sucrose) were compared. These studies revealed that swollen cells adjust their volume by decreasing the amount of intracellular K+ and ninhydrin positive substances. Intracellular Na+ and ATP concentrations were unchanged. Accordingly 42K+ flux analysis showed that the (passive) cell membrane permeability for K+ is increased to a minor degree and the Na+ permeability unaffected. The increased K+ permeability could not be correlated to an increase in 45Ca2+ influx.
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  • 188
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    Journal of Cellular Physiology 84 (1974), S. 141-145 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The membrane potentials of human embryonic lung fibroblasts have been measured in different cellular environments. Sparse cells on plastic have a mean membrane potential of -8.5 mV. As the cells progress to dense culture, the mean membrane potential rises to -14.7 mV. The mean membrane potential of fibroblasts in human embryonic lung fragments by comparison was found to be -16.5 mV. Sparse cells on collagen, at the same density as the sparse cells on plastic, have mean membrane potentials of -10.8 mV.Sparse cells on plastic migrating from dense cellular areas, following a cut being made in a thick sheet of cells, have mean membrane potentials of -5.9 mV.The significance of these results in relation to cellular environments has been discussed.
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  • 189
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using a combination of DNA-cytophotometry and tritiated thymidine-autoradiography, we have shown that the majority of nondividing cells in serially propagated human diploid cell populations have the 2C DNA content consistent with their being arrested in the G1 phase of the diploid cell cycle. Unlabeled 4C cells appear increasingly with time in culture. These may be arrested G2 diploids or they may be G1 tetraploids, since there is an associated increase in polyploidy in older cultures as evidenced by the appearance of labeled 8C cells.
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  • 190
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    Journal of Cellular Physiology 84 (1974), S. 253-259 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Secondary cultures of human diploid fibroblasts were used to study the effect of pH on cellular proliferation. In nonconfluent cultures, the growth rate at pH 7.1 was similar to that at pH 7.7 regardless of serum concentration. However, the saturation density achieved at pH 7.7 at any serum concentration was always 2-4 times that achieved at pH 7.1, although the greatest differences in saturation density were observed at the higher serum levels. The results suggest that the effect of pH on saturation density is due to two factors. One, cells at pH 7.1 seem to have a greater ability to undergo contact-inhibition than at pH 7.7, independent of any serum functions; and, two, confluent cells in medium at pH 7.1 are somewhat less sensitive to growth stimulation by increasing serum concentration than are confluent cells raised in medium at pH 7.7.
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  • 191
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    Journal of Cellular Physiology 84 (1974), S. 291-299 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In phototrophic culture of Euglena gracilis, good synchrony was found only under rather restricted programs of light-dark cycles, and rather narrow ranges of temperature and light intensity, when cultures were flushed with air fortified with adequate amounts of CO2. When flushed with air alone, CO2 was found to be limiting, and while cell divisions were rhythmic, less than a doubling of cell number occurred in division bursts. With air as gas phase, rhythmic division activity was maintained over wide ranges of temperature, light intensity, and the ratio of light:dark in a given program; all these factors affected the amplitude of the division burst, however.
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  • 192
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    Journal of Cellular Physiology 84 (1974), S. 319-332 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Embryoid bodies are produced when a transplantable testicular teratoma from strain 129 mice is serially passaged in the peritoneal cavity of these mice. These bodies are roughly spherical containing two morphologically distinct cell types. Scanning and transmission electron microscopy have been employed to show that the endodermal cells of embryoid bodies, like those of the mouse embryo, are on the outer surface and have highly convoluted surfaces containing numerous microvilli-like projections. The inner, embryonal carcinoma cells, are the pluripotent stem cells of this tumor.Intracisternal A-type particles have been observed in electron micrographs and are almost exclusively located in the endodermal cells of the embryoid bodies. The A-type complement-fixing antigen has been identified in extracts prepared from this tumor.When embryoid bodies are placed in culture and allowed to attach to the surface of a petri dish, a large number of new morphologically distinct cell types appear. Attachment to the petri dish surface is required for the generation of these new cell types. Cells of similar morphology in culture, display a distinctly “clonal” distribution on the petri dish surface.
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  • 193
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    Journal of Cellular Physiology 84 (1974), S. 481-485 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Following enucleation of a portion of human culture cells containing 3H-pyridine nucleotides, autoradiography revealed no difference in the grain density over enucleated and whole cells. These results provide evidence that the concentration of pydine nucleotides does not differ by more than threefold between nucleus and cytoplasm and probably does not vary at all.
    Additional Material: 2 Ill.
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  • 194
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 83 (1974), S. 11-18 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A single hematocytoblast in the yolk sac of the chick embryo has been shown previously to give rise on the average to a clone of 128 erythrocytes. Furthermore, in any given generation the erythroid cell synthesizes a characteristic amount of hemoglobin (Hb). In these experiments day 4 embryos were treated with FUdR for 12 hours, and then reversed with thymidine. We have monitored both the passage of these erythroblasts through the cell cycle, and the effect of this perturbation on the Hb content of single cells. As a result of this disruption the amount of Hb synthesized in a given generation can be varied, but the final amount of Hb/cell in the mature erythrocyte is the same as in the untreated controls. Apparently the total amount of the Hb/cell does not in itself influence the passage of the cell through the cycle. The coefficients of variation of the Hb values in the mature erythrocytes from both normal an perturbed embryos are similar.
    Additional Material: 3 Ill.
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  • 195
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 83 (1974), S. 43-51 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This paper reports the isolation of a phenotypically stable line of Chinese hamster ovary cells which exhibits a temperature dependent alteration in the transport of some purines. The alteration manifests itself for the uptake of guanine, hypoxanthine, azaguanine and guanosine but not for adenine, adenosine or thymidine. Studies with crude cell extracts suggest that, at the temperature the alteration is being expressed, the HGPRT activity is within the normal range. In cell-cell hybridization studies the alteration behaves as a recessive genetic trait.
    Additional Material: 6 Ill.
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  • 196
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 83 (1974), S. 69-74 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mammalian cell populations may be enriched for temperature-sensitive (ts) mutants by the tritiated thymidine (3H-TdR) suicide procedure (Thompson et al., '71). Such procedures were carried out on the near-diploid Chinese hamster ovary (CHO) cell line and on a line made “tetraploid” by Colcemid treatment. Clones of ts mutants were obtained from the diploid line, but in spite of repeated attempts, no ts mutants were isolated from the tetroploid line. The phenotypes of the new diploid ts mutants recovered were consistent with the particular selection regime employed.
    Additional Material: 2 Ill.
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  • 197
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In cultured fibroblasts, a mutation resulting in deficiency of a pyrimidine salvage enzyme leads to excretion of related pyrimidines. For example, absence of thymidine kinase led to loss of thymidine and deoxyuridine, and absence of deoxycytidine kinase to loss of deoxyuridine. Both wild type and mutant cells excreted uracil; if established lines are representative in this respect, a fully adequate salvage system for uracil does not seem to be present in the fibroblast.
    Additional Material: 1 Ill.
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  • 198
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 83 (1974) 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 199
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 83 (1974), S. 345-351 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ornithine decarboxylase activity in high density, stationary phase rat hepatoma (HTC) cells in suspension culture has an extremely short half-life of between 5 and 15 minutes, as measured after inhibiting protein synthesis. Following dilution of these cells into fresh medium there is a large increase in ornithine decarboxylase activity, reaching a peak often several hundred times the initial level at about four hours. At least part of this stimulation is due to an increase in the apparent half-life of the enzyme, to between 30 and 90 minutes. Evidence is presented that the supply of amino acids can control the turnover of ODC under some conditions. For example supplementing high density cells with glutamine, asparagine, serine, glycine and proline, either singly or together, increases ODC activity and decreases its apparent turnover. The stimulation by amino acids is enhanced by serum.
    Additional Material: 4 Ill.
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  • 200
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 83 (1974), S. 369-378 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mouse peritoneal exudate cells induced by thioglycollate medium can form colonies in soft agar with a plating efficiency of about 5% (0.6%-10%). Cells from an unstimulated peritoneal cavity form no colonies or have a plating efficiency of less than 0.001 %. These colony-forming cells from the peritoneal exudate are similar to bone marrow colony-forming cells in vitro in that they both require a substance(s) present in conditioned medium from L-cells or mouse embryo fibroblasts or the serum from endotoxin-treated mice for the initiation and the continuation of their growth. However, peritoneal exudate colony-forming cells have a much longer initial lag period (10-14 days) and can survive longer in the absence of L-cell conditioned medium than bone marrow colony-forming cells. Only mononuclear cells, presumably macrophages, are observed in peritoneal exudate colonies, whereas bone marrow cell colonies contain both polymorphonuclear cells and macrophages.
    Additional Material: 5 Ill.
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