bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro synthesis of polyribonucleotides
Authors: Cherepak M. M. , Hansen R. W. 
Published: December 2004

AbstractPolyribonucleotide: orthophosphate nucleotidyl transferase, commonly known as polynucleotide phosphorylase catalyzes the reversible polymerization of ribonucleoside diphosphates with the liberation of orthophosphate. The equilibrium constant is approximately 1.0. Although isolated from a variety of sources, the enzyme occurs essentially as two types: one which does not require a primer for reaction initiation and a second which does. A parallel study of an E. coli preparation representing the first type and an M. lysodeikticus preparation representing the second showed differences other than the primer requirement. Rates of polymerization were different as were the Kms. The E. coli preparation catalyzed the synthesis of polyguanylic acid while the M. lysodeikticus preparation did not although synthesis of hetoropolymers containing guanylic acid was catalyzed by the M. lysodeikticus enzyme. Use of repurified commercial substrates made the validity of some primer‐requirement experiments suspect. End group analysis of product polymers served only to raise questions concerning the reaction‐initiating compounds and the reaction mechanism. A study of hetero‐polymer synthesis showed not only that the rate of polymerization was different, from that of homopolymers but that uncompetitive inhibition rather than competitive inhibition occurred when two ribonucleoside diphosphates were present in the reaction mixture. Furthermore, the experiments showed a preferential uptake of one substrate over another and an “enrichment” which was constant. It has also been shown that RNA polymerase, a DNA‐RNA directed polymerase, can be used to synthesize polyribonucleotides if the appropriate template is provided.
Continuous flow cultures of a HeLa cell line as a basis for a steady supply of Rubella virus
Authors: Holmström Björn 
Published: December 2004

AbstractA HeLa cell line was propagated in semicontinuous suspension culture, 85 liters final volume, and in continuous flow culture with a volume of 300 ml. or 5 liters in an autoclavable medium to which 8% calf serum had been added. A medium containing 0.1% Methocel and 2% calf serum was also tested. Maximum productivity was obtained at a dilution rate of 0.33 day−1 with a cell density of about 1.0 × 106 cells/ml. The same cell line was also infected with Rubella virus and the production of virus was followed at the 5‐liter cultivation level.
Slaframine: A parasympathomimetric from Rhizoctonia leguminicola
Authors: Aust S. D. , Broquist H. P. , Rinehart K. L. 
Published: December 2004

AbstractAn interesting cholinergic compound has been isolated from the fungus Rhizoctonia leguminicola grown on extracts of red clover hay. The compound was characterized as 1‐acetoxy‐8‐aminooctahydroindolizidine and given the name “slaframine.” It has been shown that slaframine is not the active compound but is converted to the active metabolite by liver microsomal enzymes. Physiological studies with slaframine point out that it is a potent stimulator of exocrine glands. In addition, its long duration of action and low toxicity suggest that it may have therapeutic value. Preliminary data suggest that slaframine is a potent stimulator of pancreatic activity, and its long duration of action results in a stimulation of protein synthesis by the gland.
Emetic material associated with Fusarium species in cereal grains and artificial media
Authors: Prentice Neville , Dickson A. D. 
Published: December 2004

AbstractSubstances which cause emesis in pigeons were extracted from corn (Zea mays) artificially inoculated with Fusarium graminearum and from liquid culture medium inoculated with F. moniliforme, F. roseum, F. poae, F. culmorum, and F. nivale. Emetic preparations were obtained also from infected wheat (Triticum aestivum L. em. Thell), (Hordeum vulgare L. em. Lam), and durum (Triticum durum Desf). Partial purification resulted from chromatography with columns of cellulose and DEAE cellulose and with thin layers of silica gel. Two active materials were obtained from liquid culture of F. moniliforme but only one from infected cereals. Emetic preparations from F. moniliforme and infected cereals contained a polypeptide as a minor component. Ultraviolet and infrared spectrums, elemental analyses, refractive indices, and amino acid composition of the emetic from corn and one of the emeties from liquid culture of F. moniliforme were similar but not identical. Attempts to crystalline these emetics and to characterize them were unsuccessful.
Input and volume distributions for continuous cultures
Authors: Grieves Robert B. , Kao Richard 
Published: December 2004

AbstractAn analysis is presented of the effects on substrate utilization and cell growth of varying the volume distribution of and the input distribution to a model continuous‐culture unit consisting of three stirred tanks. The model is used to establish the best volume and input distributions and to indicate the effects of mixing imperfections. The Michaelis‐Menten rate expression is utilized, including an endogenous respiration term, and results are presented on unique triaxial charts. Of the distributions considered, maximum substrate utilization is achieved with 60% of the total volume in the first stage, 20% in the second stage, and 20% in the third stage and with all of the input to the first stage. At a constant fractional input to the third stage; variation in the ratio of inputs to the first and second stages has virtually no effect, except in the case that a critical dilution is exceeded. At a constant input ratio to the first two stages, an increase in the fractional input to the third stage always decreases efficiency. Three stages, regardless of relative size, are always better than one. Except for endogenous respiration effects, cell growth parallels substrate utilization.
Production of fatty acids and lipid by a Candida sp. growing on a fraction of n‐alkanes predominating in tridecane
Authors: Ratledge Colin 
Published: December 2004

AbstractA Candida sp. was grown on a fraction of n‐alkanes (dodecane 22%, tridecane 48%, tetradecane 28%) as sole carbon source. The growth rate was increased most markedly by using high concentrations of n‐alkanes (16.7% v/v). When grown in a 5 liter fermentor, the yeast reached its highest yield (60 g. of cell dry wt/l) with a concomitant high yield of fatty acids (21 g of fatty acids/l), by using a nitrogen‐deficient medium. To achieve good growth, it was essential to use an inoculum (1 part into 10) of rapidly growing cells and beneficial to increase the agitation rate gradually once growth had begun. After 108 hr maximum conversions of substrate to product were: 71.5% (w/w) for alkanes into cells and 24.8% (w/w) for alkanes into fatty acids. Of the, total fatty acids at the end of the fat‐accumulating phase of growth 54% were shorter in chain length than palmitic acid (C16H32O2). When grown on glucose, as sole carbon source, less than 2% of the total fatty acids were shorter than palmitic acid. When n‐alkanes were added to cells growing on glucose, short‐chain fatty acids (C10 to C14) were synthesized immediately, indicating a derepressed enzyme system for hydrocarbon assimilation and the absence of diauxie. The production of these acids was at the apparent sacrifice of linoleic acid synthesis. In spite of the high conversion ratios, it is concluded that it would be uneconomical to produce fatty acids, even expensive ones such as lauric acid, by microbial transformation of n‐alkanes.
Automatic analysis of gas exchange in microbial systems
Authors: Fiechter A. , Von Meyenburg K. 
Published: December 2004

AbstractAn automatically working test arrangement for the permanent analysis of O2 and CO2 in microbiological cultures is described. The measuring principle is based on the paramagnetic properties of oxygen and on the absorption of infrared by carbon dioxide. The preparation of the gas for measuring and the correction of the recording are indicated. The formula of correction was programmed and the values were calculated for a range of 3%. The routine correction of analysis values is done with a nomogram established on the basis of these individual values. The advantages of the described test arrangement are illustrated by two examples of growth experiments on Saccharomyces cerevisiae.
Virus particle quantitation and its application to virus–host cell interactions
Authors: Galasso G. J. 
Published: December 2004

AbstractVirus quantitation is discussed stressing the discrepancy between the biological titer and the physical virus particle count. When both these techniques are used in conjunction, one can more realistically catalog viral properties. The merits of this technique are exemplified in a study of the growth kinetics and properties of vesicular stomatitis virus in tissue culture.
Application of a multiple surface tissue culture propagator for the production of cell monolayers, virus, and biochemicals
Authors: Schleicher Joseph B. , Weiss Ronald E. 
Published: December 2004

AbstractA new concept of tissue culture equipment and procedures was developed for the mass‐scale growth of several types of animal tissue cells in monolayers on multiple glass surfaces. Continuous, cell lines, primary and diploid cell strains were grown in this equipment. Cells studied include primary bovine kidney, human diploid WI‐38, human foreskin, and mouse CCL1 cells. Photomicrographic comparisons of cells grown by these techniques indicate they are morphologically identical to tissue culture cells grown in glass bottles or tubes. The growth of the tissue culture cells in the propagator was monitored by carbohydrate Utilization and acid production. Large‐scale production of viruses and biochemicals on cells grown in the multiple‐plate tissue culture propagator was accomplished. Virus titers were equal to those obtained from conventional bottle or tube cultures for several strains of influenza, parainfluenza, and respiratory syneytial viruses. High‐titred mouse interferon was also produced in this system. In addition to tissue culture cell production, Eaton agent, Mycoplasma pneumoniae was grown on the multiple glass surfaces on a mass scale.
Equipment for the recovery of precipitates from tubular centrifuges
Authors: Miller G. , Mizrahi A. , Shawit G. 
Published: December 2004

AbstractEquipment has been developed for the recovery of precipitates from rotors of industrial tubular centrifuges. A double piston is described for nonaseptic discharge of precipitates through the outlet holes of the clarifier rotor. For the aseptic resuspension or dissolving of valuable precipitates a closed‐circulation system has been developed, which is applied without opening of the clarifier rotor.
Kinetics of gas diffusion in mammalian cell culture systems. I. Experimental
Authors: McLimans William F. , Crouse Elizabeth J. , Tunnah Kenneth V. , Moore George E. 
Published: December 2004

AbstractIt has been demonstrated experimentally that the thickness of fluid overlay in conventional tissue culture systems limits the oxygen available to mammalian cells growing as a submerged monolayer. A rocker culture system is described which circumvents critical problems associated with thin film culture while permitting nearly unlimited access of oxygen to the cell monolayer. Good growth of primary hepatic cells as isolated sheets has been obtained.
Use of the glucose oxidase system to measure oxygen transfer rates
Authors: Hsieh D. P. H. , Silver R. S. , Mateles R. I. 
Published: December 2004

AbstractThis investigation used the glucose oxidase system to simulate oxygen transfer rate in fermentation broths. It was demonstrated that the fungal preparation contained sufficient lactonase activity so that D‐glucono‐δ‐lactone did not accumulate and that the rate of production of gluconic acid was proportional to the oxygen uptake rate. Enzyme concentrations of 1.5–2 g/1 were found adequate to determine oxygen absorption rates in shake flasks while maintaining the dissolved oxygen concentration of low levels. The apparent Michaelis constant for oxygen, Km(O2), was found to be 27% saturation with air; this value along with experimentally determined uptake rates could be used to calculate dissolved oxygen concentration in lieu of using a dissolved oxygen probe. Enzyme concentrations of 5 g/l were sufficient to give linear acid production and low dissolved oxygen concentrations in a bench‐scale fermenter with no foaming or enzyme deactivation. The method is considered more valid and easier to employ than previously utilized techniques such as sulfite oxidation. Extension of the system to evaluating aeration effectiveness and scaleup of fermentation equipment is discussed.
Kinetics of continuous cultivation
Authors: Kono Takehiko , Asai Tsunetomo 
Published: December 2004

AbstractKinetic, studies were made on continuous cultivation applying the theory of microbial cell growth that was derived previously by the authors introducing the concepts of critical concentration and coefficient of consumption activity. General equations for microbial cell concentration for continuous cultivation in continuous‐stirred tank and tubular type reactors were derived theoretically. Productivity of cell mass in continuous cultivation was analyzed kinetically and the behavior of mutant populations in continuous cultivation is briefly discussed.
Factors affecting the flocculation of bacteria by chemical additives
Authors: McGregor W. C. , Finn R. K. 
Published: December 2004

AbstractPure bacterial cultures can be flocculated by a variety of chemical flocculants. Flocculation of bacteria will assist in their recovery, especially where the cells themselves are of interest, as in microbial protein production. Studies with several genera of bacteria indicate that the mechanism of flocculation is highly complex. Such interacting variables as temperature, ionic environment, physiological age, flocculant, bacterial genus, and surface shear have been observed. Jar test experiments with washed cells indicate that many of the variables are related to the release by the cell of proteins, nucleic acids, or polysaccharides. When released, these polymers may increase the required dosage of flocculant for recovery as in the case of E. coli, or the dosage may decrease as it does for Lactobacillus.
Continuous enzymatic saccharification of cellulose with culture filtrates of trichoderma viride QM 6a.
Authors: Ghose Tarun K. 
Published: December 2004

AbstractContinuous saccharification of Solka Floc (cellulose pulp) in single and four‐vessel stirred‐tank reactor systems has been possible employing enzymes obtained directly from submerged fermentation of Trichoderma viride QM 6a. Studies on the effect of modification of the solid substrate, enzyme stability, substrate concentration, and the influence of reducing sugar concentration on the rate of hydrolysis are reported. While susceptibility of substrate to digestion is not affected by heating alone, it is strikingly increased by heating plus grinding, or by grinding following heating. Batch and steady state continuous saccharification experiments have yielded more than 5% reducing sugar in the effluent with a dilution rate of 0.025 hr−1 at 50°C, at a substrate level of 10%. An average glucose concentration of 3.4% has been obtained in the effluent of a continuous saccharification using 5% substrate at the same dilution rate and temperature.
The isolation of an aliphatic amidase from Pseudomonas aeruginosa
Authors: Lilly M. D. , Clarke P. H. , Houldsworth M. , Currie J. A. , Dunnill P. 
Published: December 2004

AbstractA pilot‐scale process for the isolation of an aliphatic, amidase from Pseudomonas aeruginosa has been developed. A constitutive, partially irrepressible mutant was employed to give a high initial enzyme concentration. An existing laboratory isolation procedure has been scaled up and modified particularly by substitution of polyethylene glycol for ammonium sulfate precipitation as the first stage in the conversion of the fractionation to continuous operation. Full recovery of activity was achieved with the modification. The recovery of enzyme from a subsequent chromatographic stage was 85% and the maximum overall purification was 28‐fold.
Preparation and use of insolubilized amyloglucosidase for the production of sweet glucose liquors
Authors: Wilson R. J. H. , Lilly M. D. 
Published: December 2004

AbstractAmyloglucosidase (EC. 3.2.1.3), partially purified from an Aspergillus species, was chemically attached to DEAE cellulose using the bifunctional reagent 2‐amino‐4,6‐dichloro‐s‐triazine. The action of the insolubilized enzyme derivative on dilute maltose and dextrin solutions was studied in a packed bed. A second and deeper bed was used to demonstrate the possibility of a continuous process for raising the dextrose; equivalents of “glucose” liquors of high concentration formed by acid hydrolysis of maize starch.
Clutivation of yeast on gas oil
Authors: Munk V. , Dostálek M. , Volfová Olga 
Published: December 2004

AbstractThe results achieved by the cultivation of the yeast. Candida lipolytica on gas oil are referred. By using a distillation fraction of gas oil distilling between 180–400°C, containing 10–20% of n‐alkanes, the optimal condition for biomass production and deparaffination were estimated for various dilution rates and various amounts of gas oil in the medium. The main factor, which influences the yield coefficient by hydrocarbon fermentation is the polyauxie of the hydrocarbon substrate. The penetration of dispersed hydrocarbons into the yeast cell is demonstrated on electron micrographs and the velocity and reversibility of this process is estimated by using tritium‐traced hexadecane.
Microbial transformation of hydrocarbons. II. Growth constants and cell composition of microbial cells derived from n‐alkanes
Authors: Wagner F. , Kleemann Th. , Zahn W. 
Published: December 2004

AbstractCultivation of Norcardia sp., Mycobacterium phlei, and Candida lipolytica in inorganic salt solution containing n‐alkanes C10–C20 as solo carbon and energy source was investigated. Generation times of 0.5–7.0 hr were typical during the exponential growth phase. The final cell concentrations (dry weight) were usually 9–26 g/l with n‐alkane mixtures ranging from n‐decane through n‐eicosane. A linear dependence was found between the production of cell mass and the consumption of n‐alkanes. The rest concentration of n‐alkanes in the cell mass is in all experiments smaller than 0.5% (w/w). Cell yields were Ysub 60–142% and for Ye 50–97% based on n‐alkane utilization. In one case, with the Nocardia NBZ 23, the substrate specifity on hydrocarbons and on a n‐alkane mixture C10‐C20 was studied. The cell mass recovered from the fermentations contained 47.8–57.7% carbon, 5.6–9.95% nitrogen, 7.2–9.4% hydrogen, 35–62% crude protein, and 6–36% lipid. Cellular protein and lipid synthesized by an organism is influenced by the type of nitrogen source. The amino acid, glucosamine, muramic acid, 2,6‐diaminopimelinic acid, and fatty acid distribution in organisms grown on n‐alkanes compared with a corresponding fermentation on glucose as sole carbon source were also estimated.
Growth models of cultures with two liquid phases. I. Substrate dissolved in dispersed phase
Authors: Erickson L. E. , Humphrey A. E. , Prokop A. 
Published: December 2004

AbstractMathematical models which can be used to describe batch growth in fermentations with two liquid phases are developed for systems in which the growth limiting substrate is dissolved the dispersed liquid phase. In the models, the possibilities of growth occurring at the surface of the dispersed phase and in the continuous phase are considered. It is assumed that the composition of the dispersed phase is such that substrate utilization from it causes little of no change, in interfacial area. Three special cases are examined. In the first, it is assumed that all growth occurs at the surface of the dispersed phase. In the second and third, it is assumed that growth occurs both at the interface and in the continuous phase. The second case assumes that substrate equilibrium is continuously established between the two phases while the third assumes substrate consumption in the continuous phase is limited by rate of transport of substrate to that phase. Comparison of the first model with available experimental data shows good agreement between model and data.
The response by microorganisms to steady state growth in controlled concentrations of oxygen and glucose. I. Candida utilis
Authors: Moss F. J. , Rickard Pamela A. D. , Beech G. A. , Bush F. E. 
Published: December 2004

AbstractDissolved oxygen and glucose concentrations have been independently maintained at various concentrations for extended periods during growth of Candida utilis in continuous culture. Simultaneous observations of cytochrome concentration, growth rate, rates of uptake of oxygen and glucose and rates of production of CO2, ethanol and acid have been made during steady states at various levels of oxygen and glucose. There is an inverse relationship between dissolved oxygen and cytochrome and between glucose cocentration and cytochrome.Studies of the transient state following a step change from high to low dissolved oxygen show that there is a lag of about 10 hr during which there is no change in the above parameters. This is followed by rapid oscillatory changes in cytochrome content and a change to a more fermentative metabolism.
The relationship between critical oxygen level and antibiotic synthesis of capreomycin and cephalosporin C
Authors: Feren C. J. , Squires R. W. 
Published: December 2004

AbstractThis paper illustrates the type of conclusions which may be reached by the use of an electrode for measuring oxygen tension in fermentation broths. The critical oxygen level, based on oxygen uptake, and the minimum oxygen tension necessary for maximum antibiotic synthesis for two commercial antibiotic fermentations, capreomycin and cephalosporin C, were studied. Capreomycin yields were depressed at an oxygen tension which was slightly below the critical oxygen level. Cephalosporin C synthesis was depressed at an oxygen tension higher than the critical oxygen level.
Effects of oxygen and glucose levels on lipid composition of yeast candida utilis grown in continuous culture
Authors: Babij T. , Moss F. J. , Ralph B. J. 
Published: December 2004

AbstractTotal lipids were extracted from the cells of Candida utilis grown at a constant population density in continuous culture. At different steady states, the environment was controlled with respect to dissolved oxygen and glucose concentrations, pH and temperature. Gas liquid chromatography was used to follow quantitative and qualitative changes in the fatty acid composition of the cells. Increasing glucose concentration resulted in higher lipid content; high oxygen concentrations increased the level of polyunsaturated fatty acids. The most significant changes in fatty acid composition took place when both glucose and oxygen concentrations were high, and under these conditions the amount, of linolenic acid was at its highest value.