bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assays of urea and arginase with a biocatalytic membrane electrode operating on conductimetric principle
Authors: Macholán L. , Filípek J. , Andrýs C. 
Published: December 2004

AbstractA bioelectrode consisting of two parallel noble metal nets and a thin layer of gel‐entrapped urease between them permits to determine urea conductimetrically with a response time 3–5 min and reproducibility 5–6% above 60 micromolar concentration of urea. Differential measurement eliminates the interference due to conductive components of the real sample. Evidence has been obtained for extended application of the method by using immobilized microbial cells or tissue slice as biocatalyst in place of the immobilized purified enzyme. It is also suitable for simple kinetical assaying arginase activity in the tissue extracts.
Productivity of cultures from secondary colonies of streptomycetes producing anthracycline antibiotics
Authors: Igina E. F. , Tulemisova K. A. , Nikitina E. T. 
Published: December 2004

AbstractAt late stages of development of surface cultures streptomycetes producing anthracycline antibiotics were shown to form secondary colonies on PRIDHAM & GOTTLIEB'S medium with xylose. Stable variants obtained from them possessed an increased biological activity (by a factor of 2–3 times) due to the accumulation of amounts of antibiotically active anthracyclines.
New synthetic route to 9α‐hydroxy‐4‐androsten‐3,17‐dione
Authors: Uszycka‐Horawa T. , Skibińska M. , Jakubowski W. 
Published: December 2004

AbstractThe new synthesis of 9α‐hydroxy‐4‐androsten‐3,17‐dione from hydrocortisone is described. The six‐step reaction sequence involved degradation of the side chain, dehydration, ketals formation, reduction of the α‐epoxide to 9α‐hydroxyderivative and ketal groups cleavage. The overall yield is about 12%. Physico‐chemical data of two new compounds were determined.
Blasenfreie Begasung
Authors: Kopp Th. 
Published: December 2004

AbstractDifferent methods of bubble‐free oxygenation are discussed. Today, the surface oxygenation has lost its importance. Technically, membrane oxygenation methods are used in various fermentervolumes although the construction principles are quite complicated. The scale‐up‐potential is here very limited. On the other hand, the CHEMCELL‐oxygenation is a simple method, safe in terms of sterility and applicable to all fermenter sizes common for cell culturing. A great benefit of this principle is that the amount of oxygenation is not dependent from the mixing parameters.
Prozeßsteuerung des O2‐Partialdruckes der Kulturlösung bei aeroben mikrobiellen Fermentationen
Authors: Grosse H. H. , Hilliger M. , Bormann E.‐J. 
Published: December 2004

AbstractFollowing the introduction referring to the fundamental role of the oxygen supply and the meaning of measured values of diluted oxygen in liquid culture media commonly used strategies to avoid the oxygen limitation in aerated fermentations are summarized and validated with respect to their realization requirements. Furthermore, a new developed principle for the control of the p O2‐value based on the growth regulating influence of the acidity (pH‐value) without using the increase of the oxygen transport rate of the fermenter is discussed.
The principle of optimality as the foundation of biotechnological modeling
Authors: Prause M. , Kaiser J. 
Published: December 2004

AbstractThere are many points of contact between optimization problems and modeling. On the one hand the model adjustment process itself as a process of estimation is closely connected with optimization, in that it is to produce what is in one sense the best possible model. The basic structure of the optimization problem as problem in decision making with the necessary input of an objective function is thus evident. On the other hand a model is never an end in itself but on the basis of its simulation capacity a means to an end, for example in biotechnological optimization. From this point of view the model is a product of scientific work and thus an economic value. Equally, through its intended purpose the model exhibits a utility value. A complete evaluation of the model as a condition of rational modeling must take into account both these aspects. That is possible in principle by adding the modeling expenditure to expenditure for the realization of biotechnological processes, expressing the economic consequences of model quality as an objective function, and minimizing the specific total expenditure for the product to be produced.Biotechnological practice requires that the “optimum” model is approached by means of iterative processes. Some practical examples will make the process clear, taking into account qualitative (semantic) and quantitative (accuracy) aspects of the utility value.
Production of high ethanol concentrations from glucose using a vertical rotating immobilized cell reactor of the bacterium zymomonas mobilis
Authors: Amin G. , Doelle H. W. 
Published: December 2004

AbstractLong‐term continuous ethanol production of up to 80 g.l1 with a volumetric ethanol productivity of 63 g. l−1. h−1 was maintained for more than 72 days using a Vertical Rotating Immobilized Cell Reactor of the bacterium Z. mobilis. Continuous production of higher ethanol concentration was unsuccessful due to an inhibition of cell growth by long exposure to high ethanol concentrations. However, ethanol concentration as high as 120g. l−1 and volumetric ethanol productivity of 13g. l−1. h−1 were achieved in a repeated‐batch fermentation system using the same bioreactor. By a simple washing operation at the end of each run, immobilized biomass could be effectively regenerated and used to carry out more than 10 successive fermentation cycles.
Fructose phosphorylation by zymomonas mobilis glucokinase
Authors: Edye L. A. , Kositanont Ch. , Doelle H. W. 
Published: December 2004

AbstractZymomonas mobilis ATCC 53431, a fructokinase negative mutant is unable to utilize fructose as a sole carbon source for growth. At high fructose concentrations, however, fructose was converted to ethanol. The fructose uptake displayed MICHAELIS‐MENTEN kinetics with an apparent Km of 185 mM fructose.Purified glucokinase from ATCC 53431 and the wild strain ATCC 29191 both exhibited fructose phosphorylating activity at high fructose concentrations with an apparent Km value of 222 mM fructose. Glucokinase substrate specificity was found not be absolute, as previously reported.
Outer membrane vesiculation of acinetobacter calcoaceticus
Authors: Borneleit P. , Kleber H.‐P. , Binder H. 
Published: December 2004

AbstractFor intact cells of A. calcoaceticus 69V susceptibility to hydrophobic agents (antibiotics, dyes) was established. The composition of its outer membrane and comparison with that of a reference strain, A. calcoaceticus CCM 5593 with a blocked hydrophobic pathway, gave no indication of phospholipid bilayer domains as the structural basis of these permeability characteristics. The outer membrane composition together with the data of time‐resolved fluorescence anisotropy measurements is indicative of a high state of order of the hydrocarbon region.A. calcoaceticus 69V releases lipopolysaccharide (LPS)‐rich membrane vesicles into the growth medium when grown on a hydrophobic carbon source. While the cells contain both R‐form and S‐form LPS, the LPS released with the vesicles is exclusively of the R‐type. The same selectivity with respect to LPS composition was observed when LPS was removed from intact cells by EDTA‐NaCl treatment which leads to a break‐down of the barrier to hydrophobic agents in A. calcoaceticus CCM 5593.We propose that due to its physical properties, R‐form LPS forms tightly packed structures within the membrane which, under certain conditions, become destabilized and liberated into the surrounding medium. As a consequence, a disturbance of the highly ordered lateral molecular arrangement might lead to altered permeability properties of the outer membrane as suggested in one of the two alternative models existing to explain permeability changes observed in deep rough mutant strains of Enterobacteriaceae.
Untersuchungen zur Oberfläuchenstruktur von Pasteurella multocida
Authors: Rosner H. , Rohrmann B. , Günther H. 
Published: December 2004

AbstractDetailed studies of the surface structures are an important requirement for the development of efficient vaccines against enzootic pneumonia in calves and piglets caused by Pasteurella multocida.Electron microscopical examination after Alcian Blue staining shows capsular material extending far into the surrounding medium.The extent of the capsules depicted by light microscopy did not correlate with virulence and immunogenicity. However, the extent of the capsules was effected by different culture conditions.The immunization with extract material resulted in a good protection against homologous infection.It has been shown that different cultivation conditions can result in heterogeneity of LPS and in altered OMP‐profiles.
Adhesins of escherichia coli
Authors: Nimmich W. 
Published: December 2004

AbstractE. coli has got increasing importance as a causative agent of intestinal and extra‐intestinal diseases. In both these infections adhesion of the bacteria to mucous surface cells are initial events for coionization and development of infection. Adhesins are bacterial recognition proteins which specifically interact with carbohydrate moieties of glycoproteins or glycolipids on mammalian cells. The adhesiveness of bacteria is associated with filamentous surface appendages, designated as fimbriae or pili, as well as with non‐fimbrial components. Some recent data on the nomenclature, classification, disease association, receptor specificity, and topographic arrangement are presented. The correlation between E. coli O : K : H serovar and fimbrial antigens is demonstrated on the basis of E. coli isolated from patients with urinary tract infections. Hitherto unknown non‐fimbrial adhesins are briefly described.
Untersuchungen zur in vitro‐ und in vivo‐Adhärenz von Bordetella bronchiseptica
Authors: Krüger M. , Nguyen A. T. , Horsch F. , Lux R. 
Published: December 2004

AbstractPathogenic strains of Bordetella bronchiseptica undergo phase changing under in vitro conditions. This is the irreversible loss of virulence factors. Adhesins are involved in these structures. They permit adhesion and colonization of bacteria to respiratory epitheliums. Phase III‐bacteria adhere as well as Phase I‐bacteria under in vitro conditions (cells of respiratory epithelium from guinea pigs).Four phase III‐strains of seven isogenic pairs adhere in a significant higher number per cell than phase I‐agents. These results are confirmed by results of investigations with phase III‐strains constructed throughout cultivation on several culture media. Phase III‐bacteria colonize in significant lower numbers under in vivo conditions in rabbits and guinea pigs. Purin auxotrophic mutant strains colonize less in guinea pigs than in rabbits. In vitro adhesion does not reflect the real bacteria‐host interaction between adhesin and receptor.
Die gelenkte Biosynthese immunogener Strukturen für die Impfstoffproduktion am Beispiel Bordetella bronchiseptica
Authors: Kludas K.‐H. 
Published: December 2004

AbstractIt is described how Bordetella bronchiseptica forms biomass mainly from L‐glutamic acid and L‐proline. Glucose‐6‐P is prepared by gluconeogenesis with the aforesaid amino acids and by phosphorylization of starch by phosphorylase and cAMP serving as signal substance. Synthesis of the heatsensitive toxin is mainly effected by yeast extract and a trypton at low redox potential. The capsule is synthesized by nicotinic acid amide, peptides, glycerol, glucose, ascorbic acid, and Mn‐ions. The fimbria development is positively influenced by the taurine, L‐glutamic acid, L‐histidine, and polysaccharides, The necessary immunobiological parameters for vaccines are optimally developed by Bordetella bronchiseptica when observing the requirements for cultivation.
Amorphous‐cellulose dispersing activity of cellobiohydrolase I of trichoderma reesei, suggestion for an interpretation of the C1‐effect
Authors: Heitz H.‐J. , Witte K. , Wartenberg A. 
Published: December 2004

AbstractTwo isoenzymes of cellobiohydrolase I (CBHI/1 and CBHI/2) of Trichoderma reesei purified from CelluclastTM are shown to cause a new mode of reaction which is exhibited additionally to the known exo‐glucanase reaction of CBHI: Dispersion of amorphous cellulose solution is increased by CBHI/1 and CBHI/2 to 49 and 64 p.c., respectively, before decompositions of substrate as induced by the same enzymes become detectable. Amorphous‐cellulose dispersing activity of CBHI is reduced by cellobiose which is known to be an inhibitor of CBHI. Amorphous‐cellulose dispersing activity was also observed of a CBHII isoenzyme (CBHII/2), an endo‐glucanase and complete Celluclast, however, to lesser extents (17, 12, 35 p.c., respectively). Observations with a phase‐contrast microscope determined an increase of dispersion of particles of amorphous cellulose induced by cellulases of Celluclast. Decompositions of amorphous cellulose run almost linearly and quite exponentially when induced by CBHI and CBHII, respectively, allowing differentiation between exo‐glucanase and endo‐glucanase activities of these cellulases.
1‐acetyl‐β‐carboline, a new metabolite of streptomyces kasugaensis
Authors: Proksa B. , Uhrín D. , Šurdíková M. , Fuska J. 
Published: December 2004

Abstract1‐Acetyl‐β‐carboline, isolated as a metabolite of an actinomycete for the first time, was obtained from the culture filtrate of Streptomyces kasugaensis. The separated compound was identified by spectral means. Production of 1‐acetyl‐β‐carboline was substantially rised after addition of equimolar amounts of DL‐tryptophan and DL‐alanine into the cultivation medium.
Purification and partial characterization of external and internal invertases from two strains of trichosporon adeninovorans
Authors: Büttner R. , Schubert U. , Bode R. , Birnbaum D. 
Published: December 2004

AbstractWe investigated the extracellular and intracellular invertase activity of two Trichosporon adeninovorans strains. Both strains (SBUG 724 and CBS 2844) secrete one invertase into the medium. The external enzymes were purified by chromatography on hydroxylapatite. The molecular weight of the external invertase of SBUG 724 was found to be 650,000 and of CBS 2844 450,000. The internal invertases were separated by DEAE‐cellulose chromatography. The molecular weight of the enzyme from CBS 2844 was estimated to be 125,000. In the strain SBUG 724 we found two internal invertases (Mr 230,000 and 70,000). The activity of all invertases has similar properties. The pH optimum of the reaction was determined between 5.0 and 5.2 and the temperature optimum was 60 to 70°C. The Km value for sucrose was determined to be 71 to 83 mM and for raffinosc 27 to 36 mM.
Characterization of biotechnological processes and products using high‐performance liquid chromatography (HPLC) VI. Determination of lactic acid and short‐chain carboxylic acids C1–C5
Authors: Gey M. , Klossek P. , Becker U. 
Published: December 2004

AbstractLactic acid and short‐chain carboxylic acids C1–C5 were analyzed on an Aminex HPX‐87H column using UV and RI detection. The HPLC method was applied to complex fermentation media of a microbial lactic acid formation process. The resulting chromatograms of the yeast extract or culture medium showed some UV‐absorbing substances that interfered partially with peaks of short‐chain carboxylic acids.In contrast to UV monitoring, RI detection gave only a few small peaks of these so‐called “background chromatograms”. Also glucose used as substrate could be quantified in the culture medium, because of which RI detection should be preferred.Furthermore, a self‐prepared cation‐exchange resin (SAC = S‐DVB) based on a poly(styrenedivinylbenzene) partially comparable in its properties with Aminex resins was useful for fast (about 4 minutes) and not too expensive determinations of lactic and acetic acid in fermentation media.Applying this separattion system to fermentation solutions detected by RI as well as UV monitoring results in the quantitative analysis of lactic acid kinetics identical with an Aminex HPX‐87H column were achieved.Finally, the simplicity of lactic‐acid analysis is illustrated by examples of dairy products only centrifugated and diluted in double distilled water before injecting on a cation‐exchange column.
Accumulation of heavy metals by oscillatoria sp.
Authors: Bhattacharya D. N. , Ghosh R. , Pal S. C. , Sen S. K. 
Published: December 2004

AbstractMicroorganisms are the dominatign inhabitants of the soil, and there is an icnreasing tendency to apply heavy metals in agricultural practice. The ecological balance may be distrubed unknowingly if we do nogt measure the tolerance by the microorganisms of these heavy metals. It has been found in a Oscillatoria model system that widely used heavy metals have a high degree of toxicity to this cyanobacter.
Concentration of microorganisms in microbial suspensions
Authors: Pätz R. 
Published: December 2004

AbstractFor technical research and development with high cell densities the volume concentration plays an important role. On the basis of simple determinations of a density concentration relationship a method is described which allows a better calculation of the real density of biomass and of dry matter as used till now. As results of simple relations for spherical particles an average water content and the volume fraction may be derived.
Embryo manipulation – present and future
Authors: Plesník J. , Bulla J. , Bavin V. 
Published: December 2004

AbstractThe article presents a survey of the modern state, application, and prospect of development of present‐day biotechnological methods of intensification the animal production using existing large genetic potential of animals as well as of new genetically transformed animals by the method of introduction of the genetic material on one type or species organism into another one.Recent succes in molecular biology, genetics, embryology and physiology of animal reproduction anables to influence purposefully the process of embryogenesis. In this connection, the role of mammalian embryotransfer method become even more prominent. It secures the final results and their evaluation following various effects on the embryo.
Biological plant protection
Authors: Kleinhempel H. 
Published: December 2004

AbstractBreeding of high‐yielding varieties of cultivated plants has led to spectacular results in the past 30 years. Since the genetically fixed yield potential has been exhausted to a very large extent, it is necessary to take intensive plant protection measures in addition to ensuring high nutrient supply. Plant protection has made a highly recognized contribution to the impresssive development of yields in the last few decades.
Bakers' yeast mediated preparation of s (+)‐6‐methyl‐5‐hepten‐2‐ol, the pheromone of an ambrosia beetle
Authors: Kaminska J. , Markowicz L. , Stolowska J. , Gora J. 
Published: December 2004

Abstract6‐Methyl‐5‐hepten‐2‐one was reduced in 64% yield to the title compound of > 90% enantiomeric excess by bakers' yeast which had been kept in aqueous ethanol under aerobic conditions in the absence of carbohydrates.
Methanol metabolism and ammonia assimilation in four methylophilns strains
Authors: Elrayes E. G. , Banat I. M. , Hamdan I. Y. 
Published: December 2004

AbstractMethanol assimilation and dissimilation pathways and ammonia assimilation pathway were investigated in four obligate methanol‐utilizing bacteria through the detection of key enzymes. Both hexulose phosphate synthetase and hexulose phosphate isomerase, key enzymes of the ribulose monophosphate pathway (RMP) for methanol assimilation were detected whereas four key enzymes (hydroxy pyruvate reductase, isocitrate lyase, malyl‐CoA‐lyase and glyoxylate aminotransferase) that are characteristic of the serine assimilation pathway were absent. Key enzymes for the two methanol dissimilation pathways, the linear sequence enzymes formaldehyde and formate dehydrogenase and the RMP cyclic sequence enzymes glucose‐6‐phosphate dehydrogenase and 6‐phosphate giuconate dehydrogenase were all detected. Ammonia was assimilated via the glutamate dehydrogenase pathway and not via the glutamine synthetase and glutamate synthase pathway.
Spray drying of protein solutions concentrated by cross‐flow ultrafiltration
Authors: Mohr K. ‐H , Steube K. , Kleinschmidt Th. 
Published: December 2004

AbstractThe influence of various operating parameters as temperature, pressure, flux, solid content and operating time will be investigated for the concentration of protein solutions by ultrafiltration.The spray‐drying mechanism of protein concentrates is discussed.
Improvement of the nutritional value of rye products by solid‐state fermentation with fusaria
Authors: Klappach G. , Weichert D. , Zakordonets D. A. , Suprun S. M. , Sholkevich Y. G. 
Published: December 2004

AbstractThe use of some cereals in animal nutrition, e.g. rye, is limited because of some constituents. By solid‐state fermentation using selected Fusaria it is possible to enhance the nutrition value and to enrich the fermented material with free and essential amino acids and vitamins. The fermentation method is described and the results of analytical assays are discussed.
Some approaches to adaptive control of fed‐batch culture of the cellobiase producer aspergillus japonicus
Authors: Ananjin V. M. , Komkov A. S. , Solovjeva I. V. , Boyev A. V. , Okunev O. N. 
Published: December 2004

AbstractBiosynthesis of cellobiase by an Aspergillus japonicus culture under various modes of cultivation was studied using a fermenter‐computer system. Two modes of fed‐batch cultivation were developed: temperate and intensive. Both modes used the double algorithm of glucose supply based on the process control by the preset profile of CO2 concentration in exhaust gas and consumption of the pH stabilizing titrant. Intensive fed‐batch proved the most efficient mode: it maintained conditions for derepressed cellobiase Liosynthesis and decreased the carbon and energy limit for enzyme production. Intensive fed‐batch is, thus, the most adapted to cellobiase biosynthesis conditions and nutrient requirements of the producing culture.
Atp‐Dependent gold accumulation by living chlorella cells
Authors: Karamushka V. I. , Ulberg Z. R. , Gruzina T. G. , Dukhin A. S. 
Published: December 2004

AbstractAn effect of the Au(III) energy dependent concentration has been discovered by living Chlorella cells. The process is most intensive within the alkaline interval of pH, fading away in the dark, and is suppressed in the presence of arsenate (C ≧ 1 μM), fluorides (C ≧ 0.01 mM), sodium azide (1 mM), DCCD (10 μM), 2, 4‐dinitrophenol (0.1 mM). In the dark the process is stimulated by ATP (but not by ADP, or AMP). ATP also neutralizes NaN3 effect, but not that of DNP. An energy dependent Au(III) concentration is also observed for other green, blue‐green, and, red singlecell algae.
An aspergillus awamori mutant with enhanced glucoamylase activity
Authors: Witkowska‐Gwiazdowska A. , Ilnicka‐Olejniczak O. , Kostka G. , Czajkowska D. 
Published: December 2004

AbstractThe mutagenesis of a glucoamylase‐producing A. awamori strain yielded a mutant exhibiting an 80% increase in the level of the biosynthesis of this enzyme under liquid state fermentation conditions (LSF).
Silica carriers for immobilization of thermostable α‐amylase
Authors: Dobreva E. , Ivanova V. 
Published: December 2004

AbstractThe possibilities for immobilization of thermostable α‐amylase from Bacillus licheniformis 44MB82 on silica carriers activated by different methods have been studied. Immobilization on Ti(IV)‐activated CPG, Chromosorb P, quartz powder and pumice stone was sufficiently effective. The preparation immobilized on CPG showed a shift in pH and temperature‐profiles of enzyme action. They were found to be changed from pH 6,0–6,5 to pH 8,5 and from 90°C to 80°C, respectively, when compared to these parameters of the soluble enzyme. Immobilization leads to enhancement of thermostability. Possibilities for batchwise use of the immobilized preparation were established.