bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and biological activity of tripeptide FR113680 analogues containing unconventional amino acids
Authors: Caliendo G. , Calignano A. , Grieco P. , Mancuso F. , Perisutti E. , Santini A. , Santagada V. 
Published: December 2004

AbstractIn order to further develop structure–activity relationships and to get information about the biological active conformations we synthetized analogues tripeptide to the FR 113680 [Ac‐ Thr‐D‐Trp(CHO)‐PheNMeBzl; Ac: acethyl], in which the phenylalanine residue was replaced by unconventional amino acids [1,2,3,4‐tetrahydroisoquinoline‐3‐carboxylic acid (Tic); (3aS, 7aS)‐octahydroindole‐2‐carboxylic acid (Oic); (S,S,S)‐2‐azabiciclo[3.3.0]octane‐3‐carboxylic acid (Aoc); 3‐(1′‐naphthyl) alanine (Nap) phenylglicine (Phg); thienylalanine (Thi)]. The biological activity of the peptides was performed on guinea pig ileumfar neurokinin 1 (NK‐1) and on rat colon for neurokinin 2 (NK‐2). In particular, the replacement of the Phe3 by the Oic (8a) gave an higher antagonist activity in both NK‐1 and NK‐2 receptors, but no improvement in selectivity with respect to reference tripeptide (FR113680) The compound (8a) represent the first example of highly potent peptides that do not contain an aromatic mi no acid of the third position as had been previously considered essential. © 1995 John Wiley & Sons, Inc.
Conformation and dynamics of dimeric ureido‐balhimycin
Authors: Eberstadt Matthias , Guba Wolfgang , Kessler Horst , Kogler Herbert , Mierke Dale F. 
Published: December 2004

AbstractThe conformation of the antibiotic ureido‐balhimycin has been investigated by proton nmr and refined with computer simulations. The dimeric structure cj ureido‐balhimycin was established by unambiguous identification of 6 nuclear Overhauser effects (NOEs) as intermonomeric, out of the total of 186 NOEs observed. Via distance geometry calculations the antiparallel orientation of the two monomers was demonstrated. Further refinement by molecular dynamics simulations provided the essential hydrogen bonds and aromatic interactions responsible for interfacial stabilization. The computational protocol illustrated here (distance geometry to define the coarse topology and molecular dynamics for refinement) should find general applicability in the study of homodimers. © 1995 John Wiley & Sons, Inc.
Submerged citric acid fermentation of ferrocyanide‐treated cane molasses
Authors: Clark D. S. 
Published: December 2004

AbstractFerrocyanide‐treated cane molasses was fermented in 2.5‐l. Pyrex tower fermenters using pellets of Aspergillus niger, grown in beet molasses, as an inoculum. The success of the process depended on accurate control of the ferrocyanide concentration in the fermentation mash. Highest yields (up to 80% conversion of available sugar in 8 days) were obtained when the ferrocyanide concentration was 20 p.p.m. at the start of fermentation and then increased to 80–150 p.p.m. at the 24‐hr. period. Addition of phosphate, nitrate, or methanol to fermentation mash did not increase rate of acid production or final yield.
Use of ethylene glycol in counter flow electrophoresis and in cold concentration of DNA and protein solutions
Authors: Eliasson R. , Hammarsten E. , Lindahl T. 
Published: December 2004

AbstractCounter flow electrophoresis was adapted for temperatures down to −5°C. by the use of ethylene glycol. A method is described for evaporation of water solutions containing ethylene glycol at temperatures between −5 and −10°iC. without ice formation. These measures were found not to affect the transforming activity (two markers) of Bacillus subtilis DNA.
Carbon balance in high rate dissimilation of acetic acid in semicontinuous methane fermentation
Authors: Ghose T. K. , Gupta B. Das , Bhattacharyya B. C. 
Published: December 2004

AbstractThe nature of anaerobic methane fermentation has been studied extensively over a period of about three years by means of 10‐l. semicontinuous fermenters, with ethyl alcohol and calcium acetate as carbon and energy sources. The inoculum for the two systems was isolated by enrichment techniques from primary sewage sludge and used to initiate the processes. No subsequent seeding was necessary. The fermentation was started with a substrate carbon concentration of 50 mmole/l. which was gradually increased to 400 mmole/l.; this means that an increase of substrate level from 3000 ppm to 24,000 ppm of acetate and from 2300 to 18400 ppm of alcohol medium were effected during the study. Such high acetate tolerance of the methane organism does not appear to have been reported before; it was the results of adaptation by the organisms in a semicontinuous culture for a period of 30 months. Effect of supplementary available nitrogen on the rate of gas production at different carbon levels (acetate) was also studied. It was found from the gas analyses that CH4: CO2 ratios were always more than 2 to 3 times the theoretical values, when acetate was used as substrate carbon. At some stages of acetate breakdown the concentration of hydrogen in the gaseous products was found to be as high as 8–9%, a very significant feature of this fermentation. Although sulphate ions were carefully excluded from the constitutents of the media (Analytical reagent chemicals and double‐distilled water used throughout) during the period of study (30 months), contaminants later identified as Desulphovibrio desulphuricans were found throughout the study. Morphological study of the organisms reveal that they are short rods appearing in individual or chain form, highly motile, gram‐positive and nonflagellated, similar to Methanobacterium söhngenii Barker.
Fermentation of long‐chain compounds by Torulopsis magnoliae. II. Factors influencing production of hydroxy fatty acid glycosides
Authors: Spencer J. F. T. , Tulloch A. P. , Gorin P. A. J. 
Published: December 2004

AbstractA strain of Torulopsis magnoliae, an osmophilic yeast isolated from flowers, produced an extracellular hydroxy fatty acid glycoside of sophorose which was easily recoverable as a heavier‐than‐water “oil”. The yield of this product was greatly increased and the nature of the hydroxy fatty acid portion of the molecule was modified, within limits, by the addition of fatty acid esters, hydrocarbons, or glycerides. Yields of hydroxy fatty acids of up to 90% of the substrate added were achieved. Commercially available substrates such as tall oil fatty acids, molasses, and corn steep liquor could be used. Good aeration was necessary, and control of the concentration of nitrogenous substrates and of temperature improved the yields.
Mass cultivation of algae in pure heavy water
Authors: Daboll Homer F. , Crespi Henry L. , Katz Joseph J. 
Published: December 2004

AbstractStrains of the green algae Scenedesmus obliquus, Chlorella vulgaris, and C. pyrenoidosa 7‐11‐05, and of the blue‐green algae Fremyella diplosiphon, Plectonema calothricoides, Phormidium luridum, and Synechococcus lividus have been mass cultured autotrophically in essentially pure D2O. Closed Lucite rocking‐box units containing 5 liters of culture media can produce 1 to 2 g. (dry weight) per day of fully deuteriated algae or of fully deuteriated, fully 15N‐substituted algae. Racks for six such culture units are readily constructed from commerically available parts. Operation has been routine and essentially trouble‐free. The algae produced have proved to be an excellent source of completely isotopically substituted metabolites.
Oil cake meal for preparation of protein hydrolysate
Authors: Murti C. R. Krishna 
Published: December 2004

AbstractWith a view to preparing substitutes for liver or other animal protein hydrolysates used in the treatment of protein malnutrition, a process has been developed based on sesame and mustard cakes as the starting materials. The laboratory process has been successfully scaled up to pilot plant production to compute tentative costing schedule. Essentially the process consists in defatting the cake, isolating the protein by peptization and isoelectric precipitation, enzymatically digesting the protein isolate by papain, and concentrating the digest under reduced pressure. The final product is a light brown fluffy powder, rich in almost all the essential amino acids. Growth experiments with rats have indicated that the product is comparable to commercial casein although supplementation with lysine could further enhance its biological value.
Extraction and separation of nucleotides from Escherichia coli
Authors: Lilly M. D. 
Published: December 2004

AbstractA laboratory process for the isolation of acid soluble nucleotides from bacteria has been scaled‐up. Escherichia coli was grown in 220‐l. batches, harvested by centrifugation, and extracted with cold trichloracetic acid. The nucleotides in the extract were separated by adsorption onto a Dowex‐1 ion exchange resin column followed by elution with dilute hydrochloric acid and lithium chloride. After concentration of the effluent, the lithium chloride was removed by extraction with organic solvents. The overall yield of nucleotides was 75–80%. This elution system has also been used for the separation of nucleotides from bakers' yeast extracts.
Studies on automatically aerated biosynthetic processes. I. The effect of agitation and CO2 on penicillin formation in automatically aerated liquid cultures
Authors: Nyiri L. , Lengyel Z. L. 
Published: December 2004

AbstractThe oxygen demand of Penicillium chrysogenum culture was supplied by an automatic aeration control system on the basis of the actual respiration of the cells. The simultaneous use of the automatic aeration apparatus and a turbomixer of great shear stress revealed that some effects of agitation are independent of aeration. These effects of agitation are manifested in two ways: (1) in the increased break down of the cell clumps, thus assuring large free cell surfaces for contact with the substrates; and (2) in the increased mixing effect, which assures a continuous mass transfer towardes the free cell surfaces. These effects of the agitation can improve the yield when the O2 level is maintained near to the saturation value. By means of an automatic aeration control system, the influence of carbon dioxide on the metabolism of hyphae and the production of penicillin was found to be demonstrably inhibitory when the dissolved oxygen was above the critical concentration in the culture liquid. This result is supporting evidence for the assumption that aeration is necessary to biosynthetic processes in two equally important ways: (1) to maintain the oxygen level above the critical value; and (2) to assure ventilation, by which the carbon dioxide level may be kept below its inhibitory critical value.
An 8‐liter continuous flow culture apparatus for laboratory production of microorganisms
Authors: Tempest D. W. 
Published: December 2004

AbstractThe construction of a “Porton type” chemostat of 8‐l. working volume, based on the New Brunswick Scientific Co., Inc., Model F‐14 Fermentor, is detailed. Instrumentation for temperature, pH, and foam control, and for medium supply are described and operational problems discussed.
Studies on the plateau in oxygen uptake during exertion of biochemical oxygen demand by pure cultures of bacteria
Authors: Bhatla M. N. , Gaudy A. F. 
Published: December 2004

AbstractEvidence for generation of the plateau in oxygen uptake during exertion of carbonaceous BOD by pure cultures was sought by making long term Warburg studies using glucose and phthalic acid as substrates. One organism, tentatively identified as Escherichia intermedia, of the 57 tested, exhibited a plateau. Detailed studies on this organism indicated that generation of the plateau depended upon the type of substrate and to some extent upon the initial cell concentration employed, but not upon substrate concentration. Oxygen utilization during the second stage was accompanied by metabolism of secondary extracellular carbon source(s) produced by the cells during metabolism of the original extracellular carbon source (glucose) in the first phase of O2 uptake. The secondary substrate was registered as volatile acids. Selective inhibition of protein synthesis at various times during oxygen uptake led to the conclusion that the plateau occurred because of the need for an induction period before the secondary substrate could be metabolized. Using this organism, it was also found that a plateau could be generated during endogenous respiration. This secondary O2 utilization was accompained by uptake of organic materials excreted into the medium by the cells during metabolism of endogenous carbon sources.
Proteases of the genus Bacillus. I. Neutral proteases
Authors: Keay Leonard , Wildi Bernard S. 
Published: December 2004

AbstractB. subtilis NRRL B3411 neutral protease has been extensively purified by solvent, and salt fractional ion, pigment removal with DEAE‐cellulose followed by chromatography on hydroxylapatite, and a final passage through a Sephadex G‐100 column. The neutral protease was shown to be homogeneous by disc gel and cellulose acetate electrophoresis, gel filtration chromatography, and ultra‐centrifugation. The molecular weight was determined by osmometry and ultracentrifugation to be about 38–42,000 and the amino acid composition and zinc content determined. The general properties of the enzyme, pH‐activity relationship, stability, effect of inhibitors, and specificity are discussed. Comparative studies were carried out on the B. subtilis NRRL B3411 and B. subtilis var. amylosacchariticus neutral proteases and these enzymes were found to be indistinguishable by the methods used, but quite distinct from the thermostable enzyme thermolysin from B. thermoprotcolyticus.
Pilot plant isolation of transaldolase from Candida utilis
Authors: Blair H. E. , Charm S. E. , Wallace D. , Matteo C. C. , Tsolas O. 
Published: December 2004

AbstractThrough the use of pilot plant equipment, transaldolase types I, II, and III (from Candida utilis) have been separated and purified. The procedure includes a time sensitive solvent fractionation below 0°C, ion exchange chromatography, and crystalization. The enzyme yield represents a 41% recovery of crystalline type III and partially purified types I and II.
Significance of microbial interactions in control of microbial ecosystems
Authors: Gall Lorraine S. 
Published: December 2004

AbstractA microbial ecosystem represents a delicately balanced population of microorganisms each interacting with and influencing the other members of the population. An understanding of the nature and effects of these interactions is essential to improving the performance of these ecologies, which are important, in such diverse processes as biological waste treatment procedures, water pollution abatement, industrial fermentations, human or animal digestives processes and in soil. There are several types of mocrobial interactions, such as commensalism, inhibition, food competition, predation, parasitism, and synergism, which either singly or in combination may influence the functioning of the microbial ecology.To understand interactions, it is necessary to perform a detailed study of the physiology of the individual predominating microorganisms to establish their requirements with respect to such environmental factors as nutrients, temperature, pH, oxidation‐reduction potential, removal of waste products, or toxic materials which may be involved in control processes and to determine how these factors affect their capabilities. The sum total of this information will indicate the possible interactions between the microorganisms and will form the basis for conducting experiments either in the laboratory or with mathematical models. Such experiments will lead to an understanding of microbial activities and to the formulation of control measures, often using an alteration of the environmental factors for regulation of the microbial ecologies. Extensive research remains to be done on the microbial interact inns in obtain the desired, precise control of these ecological processes.
Capsular protection against virulent coliphage infection
Authors: Paynter M. J. B. , Bungay H. R. 
Published: December 2004

AbstractThe ecological significance of bacterial capsules when virulent bacteriophages are present was explored by exposing continuous cultures of Escherichia coli ATCC 11303, in various stages of capsulation and clumping, to a virulent coliphage, T2. Only partial protection was provided by capsulation, but this could be a factor affecting survival in complex mixed cultures.
Responses in continuous cultures of lysogenic Escherichia coli following induction
Authors: Paynter M. J. B. , Bungay H. K. 
Published: December 2004

AbstractBacteriophages are widely distributed in nature and may be important factors in regulating populations of their hosts. Model continuous culture systems of a single bacterial species and a temperate parasitic phage have been studied. Steady state cultures of lysogenic Escherichia coli 159T− (λcts) produced a small quantity of free λ cts phage. Temperature shocking such a culture resulted in a sharp increase in phage concentration with a concomitant fall in cell population. With time the system returned to a steady state condition.
An analysis of models describing predator‐prey interaction
Authors: Canale Raymond P. 
Published: December 2004

AbstractMathematical models of the interaction between predator and host populations have been expressed as systems of nonlinear ordinary differential equations. Solutions of such systems may be periodic or aperiodic. Periodic, oscillatory solutions may depend on the initial conditions of the system or may be limit cycles. Aperiodic solutions can, but do not necessarily, exhibit oscillatory behavior. Therefore, it is important to characterize predatory‐prey models on the basis of the possible types of solutions they may possess. This characterization can be accomplished using some well‐known methods of nonlinear analysis. Examination of the system singular points and inspection of phase plane portraits have proved to be useful techniques for evaluating the effect of various modifications of early predator‐prey models. Of particular interest is the existence of limit cycle oscillations in a model in which predator growth rate is a function of the concentration of prey.
Oxidation‐reduction potential and concomitant growth patterns of cultures of Earle's “L” cells in centrifuge bottle spinners
Authors: Daniels W. F. , Garcia L. H. , Rosensteel J. F. 
Published: December 2004

AbstractPrevious studies of oxidation‐reduction potential (ORP) variation in monolayer (Roux bottle) cultures pointed out the need for data on pH and ORP patterns in simple spinner cultures. This information was desirable for optimizing conditions of growth in small 1‐L and New Brunswick fermentors. Results of experiments in 250‐ml centrifuge spinner vessels are presented showing that incubation of media prior to inoculation induces desirable qualities reflected in better growth. The importance of initial ORP values of the medium is discussed. The relationship of ORP levels to yield and longevity of cell growth is also considered. The ORP level of the medium at inoculation is shown to be effected by previous incubation.
A continuous, multistage tower fermentor. II. Analysis of reactor performance
Authors: Falch Edvard A. , Gaden Elmer L. 
Published: December 2004

AbstractA method for analyzing the reactor behavior of a continuous, multistage tower fermentor is described. A model consisting of a system of interconnected, ideal subreactors is set up on the basis of the fermentor's configuration and flow pattern. The residence time distribution curve is used to test the validity of the model and the relative quantities of flow streams and regions in the model are determined. A least‐square fitting procedure between measured and calculated distribution curves is used to identify the proper model. The application of this method to real cultivation conditions is also discussed. Using this approach, the multistage tower fermentor is shown to be equivalent to a cascade of four perfectly mixed tanks with a backtracking stream between stages. The extent of backflow under various conditions has also been determined.
Studies on the kinetics and mechanism of BOD exertion in dilute systems
Authors: Jennelle E. M. , Gaudy A. F. 
Published: December 2004

AbstractThe mechanisms and kinetic course of BOD exertion were compared in both open and closed systems. Two open reactors, a simulated stream device, and an open stirred reactor were employed, and the closed systems consisted of standard BOD bottles and 2.4‐liter vessels. In the closed systems, both quiescent and stirred conditions of incubation were examined. Biological solids concentration, bacteria and protozoa concentration, substrate analysis, and chemical oxygen demand as well as biochemical oxygen utilization were employed to assess the performance of these systems.Oxygen uptake rate constants were observed to increase with increasing concentration o carbon source, thus militating against irect use of the usual dilution technique for predicting rate of deoxygenation in receiving streams. The relationship between specific O2 uptake rate and substrate concentration approximated a hyperbolic function similar to the Mono relationship for specific growth rate and substrate concentration. A technique using an open stirred reactor than the standard BOD bottle dilution technique is recommended.
The effect of small amounts of sodium hypochlorite on the growth of Earl's “L” cells in suspension growth
Authors: Jordan William C. , Rosensteel John F. , Daniels William F. , Garcia Luis H. 
Published: December 2004

AbstractOf several candidate disinfectants for use in tissue culture work, especially suspension cultures, sodium hypochlorite solution was selected to test its effect on growing cells. Metabolizing cells reduce, sodium hypochlorite oxidizes ; therefore NaOCl leakage into such systems must be neutralized with no untoward effects on the cells. Dilutions of routine disinfectant‐grade sodium hypochlorite were tested against cell cultures. Those exposed to 15.62 to 31.25 ppm of NaOCl grew with no
apparent cell damage.
Optimal conditions for gramicidin S production in continuous culture
Authors: Blanch H. W. , Rogers P. L. 
Published: December 2004

AbstractIn the present study optimal policies have been evaluated for the production of gramicidin S in multistage continuous culture. An economic objective function was developed which took account of the number and size of the reaction vessels, the costs involved in antibiotic extraction, substrate costs, and variability in the selling price of gramicidin S. Optimal values of temperature and pH were 28.3 and 7.24, respectively, and independent of the stage in the system. Using the discrete maximum principle it was shown that a “cut‐off” point existed for the selling price of the antibiotic below which production was no longer profitable. Furthermore it was established that beyond 3 stages in a multistage system, only marginal gains in profitability could be made (viz., an increase in 6.3% on going from a 3‐stage to a 4‐stage system).
A mechanism of microbial cell growth
Authors: Verhoff F. H. , Sundaresan K. R. , Tenney M. W. 
Published: December 2004

AbstractPresently empirical expressions, especially the Monod equation, are used to quantitatively relate microbial growth rate to limiting substrate concentration in the solution. In this paper microbial growth is postulated to occur by a mechanism involving a mass transfer or assimilation process. The assimilation process is assumed to be substrate mass transfer limited and hence proportional to the limiting substrate concentration. The ingestion is assumed independent of limiting substrate concentration and only dependent upon internal reaction rates. The quantitative relationship between limiting substrate and microbial growth rate resulting from this mechanism is developed. Under certain limiting conditions this expression is shown to reduce to the Monod equation and under other conditions it reduces to the Lotka‐Volterra relationship. This mechanism is applied to batch and continuous cultures and the results obtained are compared quantitatively with experiment.