bluuebunny/crossref_metadata_2025_split huggingface dataset:
The production, isolation, and characterization of a grisein‐like sideromycin complex
Authors: Maehr Hubert , Berger Julius 
Published: May 2005

AbstractStreplomyces griscus var. X‐2455 produces an antibiotic complex which is active in vitro against a number of gram‐positive and gram‐negative bacteria and in mice against systemic infections caused by K, pneumoniae and D, pneumoniac. In view of the favorable chemotherapeutic index and the broad in vitro spectrum of crude concentrates, isolation of the pure antibiotic complex and the individual constituents was undertaken. The antibiotics referred to as Ho 5‐2667, Ro 7‐7730, and Ho 7‐7731 can be differentiated by tle, ultraviolet light absorption spectra, and in vitro antibacterial activities. They all contain iron and may be classified as sideromycins.From antibiotic concentrates an antibacterially inactive substance was isolated and identified as N‐acetyltyramine.
The role of polyketides in secondary metabolite production by penicillia
Authors: Tanenbaum S. W. , Nakajima S. , Marx G. 
Published: May 2005

AbstractThe participation of polyketides in the biogenesis of natural products has long been bolstered by chemical analogies. Many isotopic tracer studies have validated the acetate‐polymalonate route, via presumptive extended poly‐β‐carbonyl intermediates, to a variety of fungal metabolites. Though implicit as antibiotic precursors, the ephemeral polyketides have not been isolated, nor perhaps with the exception of acetoacetate, can oligoketides become incorporated intact into secondary metabolites. However, a prototypical oligoketides in its stable lactone form, methyltriacetic lactone (3, 6‐dimethyl‐l‐hydroxy‐2‐pyrone), has been obtained from the tropolone‐producing mold P. Stipitatum. A convenient synthesis of this metabolite, by methylation of triacetic lactone followed by partition chromatographic separation of the resultant positional isomers, has been devised. In an experiment with 14C‐formate, it was shown that the hypothetical, enzyme‐bound polyketide precursor to methyltriacetic lactone is probably involved in stipitatie arid formation, and that the origin of the “extra” methyl or methyl‐derived carbons of both substances arises from the identical “C1” pool. Radioactive tracer experiments concerning the biogenesis of pulvilloric acid, a fairly unstable antibiotic substance produced by P. Pulvillorum, showed that its exocyclic carboxyl is formed following initial methyl transfer, whereas the ring system of the molecule is essentially acetate‐polymalonate derived. In order to test the hypothesis that methyl‐branched C14 polyketide precursors to pulvilloric acid exist and may become integrated into the fatty acid multienzyme complex, presumptive fatty acid congeners to pulvilloric acid such as. 1‐methylmyristie, 4‐methyllauric, or 2‐methyllauric acids were sought. These substances were, however, absent from the mycelial fatty acid spectrum, as well as from the fatty acid moieties of a crystalline glyceridc mixture obtained from the beer. Alternative approaches to the detection or isolation of polyketides are discussed.
The synthesis of tris(hydroxymethyl)acetic acid by fermentation of pentaerythritol
Authors: Goodhue C. T. , Schakffer J. R. 
Published: May 2005

AbstractA process was devised for the synthesis of tris(hydroxymethyl)acetic acid by means of bio‐oxidation of pentaerythritol. A flavobacterium able to grow on pentaerythritol was isolated from the soil. Mutants were obtained that, were deficient, in their pentaerythritol oxidation system. These mutants could not grow on pentaerythritol, but when grown on an assimilable carbon source; they oxidized pentaerythritol to tris(hydroxymethyl)acetic acid. This conversion readily took place in a medium consisting of 20 g pentaerythritol, 10 g yeast extract, and 2 g acetic acid (neutralized) per liter. Since the mutants were unable to metabolize tris(hydroxymethyl)acetic acid, theoretical conversion yields were attainable. When pentaerythritol was added stepwise and the acid formed was neutralized continuously, 95–100% yields were obtained in concentrations of the order of 60 g/l.
Biochemical and physiological properties of an extracellular protease produced by Bacillus megateriurn
Authors: Millet J. , Acher R. , Aubert J.‐P. 
Published: May 2005

AbstractA protease, excreted by a sporogeneous strain of B. megaterium, growing exponentially in a minimum glucose ammonium medium, was isolated. It is a neutral endopeptidase, stabilized by Ca++, inhibited by o‐phenanthroline, but not by di‐isopropylfluorophosphate. The specificity, studied on insulin B‐chain, glucagon, cytochrome c, and dipeptides substrates, indicated the need for a dipeptide backbone with both substituted amino and carboxyl groups. A requirement was observed for a nonpolar lateral chain in the amino acid whose amino group was involved in the peptide bond (Leu, Phe, Ala, He, Val). Rates of hydrolysis varied also with the amino acid whose carboxyl group was involved (e.g., His > Ser > Ala > Gly). In complex medium, supplemented with Yeast Extract, the biosynthesis of the protease was repressed during growth, but the same enzyme was excreted during sporulation. The repression was apparently of the same nature as that controlling sporulation during and after growth (e.g., repression by a mixture of amino acids or high concentration of glucose). An asporogeneous mutant showed a normal product ion of protease under all conditions, and a low intracellular protease turnover after growth. A mutant unable to produce protease showed a normal sporulation and a high protein turnover. This protease, here termed megapeptidase, seems to be a typical growth enzyme, not related to either the sporulation process or to the protein turnover after growth.
Kinetics of the liquid‐phase oxidation of acid ferrous sulfate by the bacterium Thiobacillus ferrooxidens
Authors: Lacey D. T. , Lawson F. 
Published: May 2005

AbstractThe kinetics of the batch‐wise liquid‐phase oxidation of ferrous sulfate by the organism Thiobacillus ferrooxidans has been studied over a range of temperatures from 20°C to 31°C and in the presence of an abundant supply of oxygen, carbon dioxide, and other nutrients.The rate of oxidation was found to be accurately described by the equation

where t = time hr, S = concentration of ferrous ions g Fe++/1., μm = maximum specific growth rate of bacteria, hr−1. Y = mass of bacteria produced per gram of iron oxidized g/g, K = saturation constant, g Fe++/l., and X = concentration of bacteria g/1.The value for the maximum specific growth rate, μm, was found to vary from 0.12 hr−1 at 20°C to 0.20 hr−1 at 31°C, while the value for the saturation constant K varied randomly between 1 and 2 g/1.A method has also been described which permitted evaluation of the relevant rate constants μm and K without direct knowledge of the bacterial population. This method was found to yield values of μm and K which agreed with values determined accurately by a statistical regression analysis of the experimental data.
Engineering factors in single‐cell protein production. II. Spray drying and cell viability
Authors: Labuza Theodore P. , Le Roux J. P. , Fan T. S. , Tannenbaum S. R. 
Published: May 2005

AbstractOne important economical method for producing singlecell protein is to spray dry the cultured cells. This study presents some preliminary data on the effects of spray drying on cell viability. Under conditions similar to those for the production of spray‐dried milk, 4–5 log cycles destruction occurred. The results indicate that, the activation energy for thermal destruction of yeast was reduced from the normal heat treatment value of 84 kcal/°K mole to about 38 kcal/°K mole.
A dynamic mathematical model of the chemostat
Authors: Young T. B. , Bruley D. F. , Bungay H. R. 
Published: May 2005

AbstractA number of experimental studies on the dynamic, behavior of the chemostat have shown that the specific growth rate does not, instantaneously adjust to changes in the concentration of limiting substrate in the chemostat following disturbances in the steady state input limiting substrate concentration or in the steady state dilution rate. Instead of an instantaneous response, as would be predicted by the Monod equation, experimental studies have shown that the specific growth rate experiences a dynamic lag in responding to the changes in the concentration of limiting substrate in the culture vessel. The observed dynamic lag has been recognized by researchers in such terms as an inertial phenomenon and as a hysteresis effect, but as yet a systems engineering approach has not been applied to the observed data. The present paper criticizes the use of the Monod equation as a dynamic relationship and offers as an alternative a dynamic equation relating specific growth rate to the limiting substrate concentration in the chemostat. Following the development of equations, experimental methods of evaluating parameters are discussed. Dynamic responses of analog simulations (incorporating the newly derived equations) are compared with the dynamic responses predicted by the Monod equation and with the dynamic responses of experimental chemostats.
Determination of oxygen‐transfer coefficients in viscous streptomycete fermentations
Authors: Tuffile Constance M. , Pinho Fred 
Published: May 2005

AbstractTwo types of steam‐sterilizable dissolved‐oxygen probs were evaluated for use in fermentations. A galvanic‐cell probe was selected over a polarographic probe because of its demonstrated ruggedness and dependability. Various methods for determining kLa in fermentors were compared and the oxygen balance method selected for use in viscous streptomycete fermentations. Rheological data are presented to identify a range of mash viscosity where many kLa measurement methods are not applicable. Oxygen transfer data are presented for streptomycete fermentations pilot fermentors.
Enzyme inactivation with shearing
Authors: Charm S. E. , Wong B. L. 
Published: May 2005

AbstractEnzymes subjected to shearing in a viscometer are partially inactivated. It is possible with viscometry to calculate the degree of inactivation that occura when an enzyme solution flows through a capillary tube. When shear rate × exposure time is less than 104, there is little or no inactivation.The masa average shear‐rate × time or shear, for laminar flow in a cylindrical tube is simply 16L/3D. It is surprising that for a single pass through a tube, the masa average shear is independent of flow rate and shear rate.
Electrophoresis of colloidal biological particles
Authors: Lemp John F. , Asbury Eugene D. , Ridenour Edward O. 
Published: May 2005

AbstractMicroscope electrophoresis was used to measure the electrophoretic mobility of polystyrene latex particles and bacterial, and mammalian tissue cells. The submicroscopic hydrophilic colloids (gelatin, serum albumin, and staphylococcal enterotoxin B) were adsorbed on latex carrier particles to determine their electrophoretic mobility and the effect of concentration, pH, electrolyte addition, and buffer ionic strength. Mobility curves as a function of pH were established for latex particles at 1 ppm concentration indicating an isoelectric point (IEP) at pH 3.6. The IEP for Escherichia coli B cells was measured at pH 2.8, Serratia marcescens at pH 2.6, Bacillus subtilis var. niger at pH 2.9, and L strain mouse fibroblast cells at pH 4.4. Using an adsorption technique, isoelectric points were measured for proteins: gelatin (acid form) at pH 9.4, serum albumin at pH 4.9, and staphylococcal enterotoxin B at pH 6.3.Procefures for examining electrophoretic characteristics of microscopic and submicroscopic biological particles are described in order to standardize procedures and to generate results applicable to an understanding of parameters influencing concentration and purification of colloidal biological particles.
Comparison of ultrafiltration systems for concentration of biologicals
Authors: Charm S. E. , Lai C. J. 
Published: May 2005

AbstractUltrafiltration has been used with increasing frequency in recent years in biological laboratories for concentration, separation or purification of biological material. No data have been available on the comparison of the characteristics of Ultrafiltration systems currently in use. This study compares the filtration characteristics of four systems using commercially available membranes on suspensions and solutions: suspension of protein micelles (casein), cell debris (E. coli) and catalase solution. None of the four systems considered is found to be generally superior for all the suspensions and solutions. Vibration systems were most effective when relatively large particles were involved, while laminar flow recycling systems with high wall shear rates were best for dilute suspensions and proteins in solution. It was found that shearing inactivates enzymes in both recycle and vibration systems. It was also observed that vibration actually reduces flux in dilute solutions.
Preparation of L(+) β‐hydroxyisobutyric acid by bacterial oxidation of isobutyric acid
Authors: Goodhue Charles T. , Schaeffer James R. 
Published: May 2005

AbstractA process for the bacterial oxidation of isobutyric acid to L(+) β‐hydroxyisobutyric acid has been developed. The strain of Pseudomonas putida (ATCC 21244) used in this fermentation was isolated from local soil. The process was carried out in a 15‐liter fermentor over a period of 70 hr and produced L(+) β‐hydroxyisobutyric acid in conversions as high as 48%. Hydroxylation of the methyl group of isobutyric acid has special interest because it is difficult to perform chemically. The useful chemical syntheses of β‐hydroxyisobutyric acid available at present do not start with isobutyric acid and are not stereospecific.
Continuous conversion of starch to glucose with immobilized glucoamylase
Authors: Smiley K. L. 
Published: May 2005

AbstractPartially purified glucoamylase from Aspergillus awamori NRRL 3112 was immobilized on diethylaminoethyl cellulose in the presence of low ionic‐strength acetate buffers at pH 4.2. The active enzyme–cellulose complex was used to convert starch substrates continuously to glucose in stirred reactors. Substrate concentrations as high as 30% could be quantitatively converted to glucose at a rate of more than 25 mg/min/liter at 55°C for periods of 3 to 4 weeks in a 4‐liter reactor. Shutdowns were due to mechanical problems and not to loss of enzymes, which could be recovered with no appreciable loss of specific activity. Transfer products, such as isomaltose and panose, were present in immobilized enzyme‐produced syrups but to no greater degree than in soluble glucoamylase digests of starch.
A comparative study of immobilized amyloglucosidase in a packed bed reactor and a continuous feed stirred tank reactor
Authors: O'Neill S. P. , Dunnill P. , Lilly M. D. 
Published: May 2005

AbstractThe catalytic activity of amyloglucosidase covalently attached to DEAE‐cellulose was studied in a packed bed reactor and a continuous feed stirred tank reactor (CSTR) for the reaction maltose → glucose. At low flow rates mass‐transfer limitations in the bed reactor lead to lower conversions for this reactor compared to the CSTR. Simple theoretical expressions for these reactors were compared with the experimental results. There are significant differences between the kinetic parameters and pH profile of the immobilized and free enzyme. The immobilized enzyme also showed greater stability at 50°C than did free amyloglucosidase. The temperature dependence of the reaction rate was the same for immobilized and free enzyme.
Biogenesis of the L‐N, β‐dimethylleucine residue of etamycin
Authors: Walker John E. , Perlman D. 
Published: May 2005

AbstractRadioactive labeling experiments have shown that radioactivity from L‐leucine‐U‐14C is incorporated into the L‐N, β‐dimethylleucine residue of the antibiotic etamycin, and that the N‐methyl and β‐methyl groups of this latter amino acid appear to be derived from L‐methionine.
Xanthan biopolymer production at increase concentration by pH control
Authors: Moraine R. A. , Rogovin P. 
Published: May 2005

AbstractEfficient production of xanthan gum by fermentation with Xanthomonas campestris NRRL B‐1459 can be accomplished at concentrations of xanthan in the fermented broth > 3%. This level of more than twice that previously attained by us results from continuously controlling the fermentation pH with alkali. Only a slight decrease in fermentation rate and yield occurs. When ammonia is used for pH control, cell production more than doubles and fermentation time is shortened. However, xanthan yield is decreased by the diversion of additional sugar to growth.
Apparatus for continuous, large‐volume suspended cell cultivation
Authors: Fontanges R. , Deschaux P. , Beaudry Y. 
Published: May 2005

AbstractA 30‐liter apparatus for growing cells continuously is described. Samples are taken automatically, thus obviating one of the main causes of contamination. In order to eliminate the continuous introduction of a gas stream, the pH was kept constant by means of the injection of NH4OH or NaOH. Under these circumstances, and by means of the two methods of agitation described—rotary and “by Vibromixer”—a quantity of cells of approximately 4 × 1010 is harvested every 48 to 72 hr.
Sequential 11α‐hydroxylation and 1‐dehydrogenation of 16α‐hydroxycortexolone
Authors: Lee B. K. , Brown W. E. , Ryu D. Y. , Thoma R. W. 
Published: May 2005

AbstractTwo‐step microbial transformation of 16α‐hydroxycortexolone to its 1‐dehydro‐11α‐hydroxy derivative, without isolating an intermediate, was achieved with an overall yield of 72% of product at a steroid substrate concentration of 3 mg/ml. The process included formation of the cycloborate complex of the substrate, hydroxylation of the borate complex with a suspension of Aspergillus ochraceus mycelium in phosphate buffer, and dehydrogenation of the 11α‐hydroxylated intermediate with acetone‐dried Arthrobacter simplex cells. The desired product was then obtained by breaking the resultant borate complex through acidification.
Effect of mineral nutrients and organic substances on the development of Thiobacillus ferrooxidans
Authors: Tuovinen O. H. , Niemela S. I. , Gyllenberg H. G. 
Published: May 2005

AbstractThe effect of inorganic nutrients on iron oxidation by Thiobacillus ferrooxidans was studied using a concentration of 2.0 g Fe2+/liter. Besides ammonium‐nitrogen and phosphorus, the essential nutrients were sulphate and magnesium, with the lowest unlimiting concentration being 2.0 g SO/liter and 2.0 mg Mg2+/liter for a suspension of about 108 cells/ml. Omitting nitrate, calcium, potassium, and chloride had no influence on the iron oxidation. Nitrate and chloride were inhibitory in high concentrations although the bacteria were able to adapt to their presence. Several organic compounds tested in 0.5% (w/v) concentrations inhibited iron oxidation. Complete inhibition up to 14 days was caused by fructose, lactose, meat extract, yeast, extract, peptone, and tryptone. T. ferrooxidans‐strains were able to adapt to the presence of organic material even though they were not necessarily able to use the organic compounds for energy. Some general conclusions are made concerning the role of nutrients in leaching processes.
Production of gramicidin S in batch and continuous culture
Authors: Blanch H. W. , Rogers P. L. 
Published: May 2005

AbstractA mathematical model for the production of gramicidin S in batch and continuous culture is proposed. It is based on the division of the age of a cell into two phases—an immature and a mature one. A nongrowth associated product, such as an antibiotic, is assumed to be produced when the organism is in the older of these two phases, the mature state. The parameters describing the model were evaluated from batch and single stage transient continuous culture of Bacillus brevis, which produces the antibiotic gramicidin S. The predictive value of the model was studied in steady‐state single stage continuous culture and in a transient two stage system. Good agreement between the theoretical curves and the experimental results was found in the transient response of both the first and second stage systems, although at high dilution rates (0.34 hr−1) in the first stage, deviations from the predicted response were observed in the second stage. These may have been due to chemostat instability at dilution rates close to washout, lags in cell growth, and a metabolic lag on going from stage one to stage two.
The cyclone column culture vessel for batch and continuous, synchronous or asynchronous, culture of microorganisms
Authors: Dawson P. S. S. , Anderson M. , York A. E. 
Published: May 2005

AbstractA simple inexpensive apparatus with a working volume of 10 liters of culture is described. Details of construction and procedures for operation of the cyclone column vessel are given. The vessel is self‐contained, so that experimental parameters of temperature and aeration are individually controlled; homogeneous mixing and representative sampling of the culture, besides control of foam without need for antifoam, are obtained. The vessel may be used in single or multistage systems for aerobic or anaerobic cultivation of organisms in batch, chemostat, or phased cultures.
Backmixing and mass transfer in the design of immobilized‐enzyme reactors
Authors: Kobayashi Takeshi , Moo‐Young M. 
Published: May 2005

AbstractThe effects of dispersion and mass transfer resistance on the degree of conversion in an immobilized‐enzyme reactor have been considered theoretically. It is assumed that the immobilized enzymes obey a Michaelis–Menten relationship and backmixing can be characterized by a dispersion model. For two extreme cases (perfect mixing and piston flow), approximate equations are obtained, which can be readily used to evaluate the effect of mass transfer on degree of conversion. Numerical solutions are obtained for other intermediate cases. Design charts are given which set practical limits of enzyme reactor design.
Some consideration on plasmid number in a proliferating cell
Authors: Koizumi Jun‐ichi , Aiba Shuichi 
Published: May 2005

AbstractPlasmid as an extrachromosomal genetic element is an important vehicle to support the recombinant DNA technology. A picture on plasmid number per cell as a basis of expecting the gene dosage effect is worthy of drawing from the application to practice. The purpose of this communication is to present an overall and stochastic picture on the dynamics of plasmid number per cell in relation to the specific growth rate of the host cell.
Properties and quality characteristics of crystalline insulin extracted by ultrasound
Authors: Zayas Joseph F. 
Published: May 2005

AbstractCrystalline insulin was obtained from the pancreas by the method of ultrasound extraction. Extreme changes of pancreas structure were noticed, including rupture of the cells of pancreatic islands and decomposition of pancreatic tissue with the formation of micro‐and macro‐canals. These changes facilitate the migration of solvent inside the structure and washing out β cell content. Structural changes were maximal in the peripheral parts of the pancreas and in frozen pancreas treated by ultrasound. A rapid filming method recorded factors influencing the extraction process—the dispersing effect of ultrasound, the rapid destruction of pancreatic particles, and the swelling and intensive pulsation of small particles in the ultrasound field. Experimental, control, and standard insulin preparations were nearly identical in Physicochemical properties and ether quality characteristics: activity determined by a biological method and electrophoresis; homogeneity and purity determined by circle chromatography; fractions of insulin determined by starch gel electrophoresis; amino acid composition; solubility; and content of moisture, zinc, and nitrogen.