bluuebunny/crossref_metadata_2025_split huggingface dataset:
Presentation of cell membranes by freeze‐fracture electron microscopy
Authors: Meyer H. W. 
Published: December 2004

AbstractFreeze‐fracturing is especially suitable for the investigation of membrane structures. In contrast to ultrathin sectioning, large areas of the membranes are exposed. The true surface of membranes, however, can be seen only after etching (vacuum sublimation of ice) because during fracturing the frozen membrane is split between the two lipid layers. The representation of the hydrophobic region of the membrane reveals particles representing integral membrane proteins or, exceptionally, micelles of membrane lipids. Special structures on microbial membranes are, e.g., regular particle arrangements, invaginations and lipid domains with a periodic pattern of curvatures. There are still many unsolved questions concerning these structures, but the occurrence or the alteration of such structures as well as the density of “etching holes” on the membrane fracture face can be used as indicators for membrane perturbations.
Structure and serology of the lipopolysaccharides: Cell components of citrobacter
Authors: Romanowska E. , Gamian A. , Romanowska A. , Łgowski C. , Kułakowska M. , Dabrowski J. , Hauck M. 
Published: December 2004

AbstractThe genus Citrobacter consists of enteric rods that utilize citrate as a sole carbon source. Citrobacter serotypes are normal intestinal inhabitants, but some of them have been reported in gastroenteritis and in extraintestinal infections.Our immumochemical studies on Citrobacter lipopolysaccharides of chemotype G comprised serotypes: 04, 027 and 036. As we found the serotypes mentioned above are distinguished in having O‐specific polysaccharides that are homopolymers of β [1–2] linked 4‐deoxy‐D‐arabinohexopyranose. In accordance with the structural indentity, the Citrobacter lipopolysaccharides showed strong serological cross‐reactivity. Nevertheless, serotypes 04, 027, and 036 form separate entities, as observed in early studies of serologists. To find the reason for the immunological diversity the structural studies on lipopolysaccharide core regions of these Citrobacter serotypes were carried out. Three novel enterobacterial cores were identified. The complete cores 04 and 036 are decasaccharides differing in one structural element only: side‐chain glucose is present in 04 oligosaccharide in the place of galactose in the 036. The core 027 is octasaccharide.In conclusion, our structural studies have shown hitherto that in Citrobacter chemotype G group only one O‐specific polysaccharide, but three core regions, exist.
Untersuchungen zur Konstruktion von Bordetella bronchiseptica‐Mutantenstämmen durch Transposonmutagenese und deren Prüfung zur Eignung als potentielle Impfstämme
Authors: Kasprzak H. , Rehak E. , Krüger M. , Horsch F. 
Published: December 2004

AbstractThree wild type strains of B. bronchiseptica were mutagenized with the transposon Tn 5. Since the transponson Tn 5 encodes resistance to kanamycin, a selection for resistance to these antibiotics can be used as an indicator for Tn 5 transposition.9 mutants were identified that are not able to grow on minimal medium. Subsequent auxotrophic tests on these mutants revealed 7 valine, 1 cysteine and 1 valine and leucine auxotrophic mutants.It was not possible for us to find B. bronchiseptica transconjugants in the virulent phase I. All in vivo and in vitro tested parameters showed that the isolated mutants were avirulent in phase III.
Comparison of mitotic activity and growth in two long term callus cultures of matricaria recutita L.
Authors: Čellárová E. , Rychlová M. , A. Seidelová , R. Hončriv 
Published: December 2004

AbstractCallus cultures of two tetraploid plant of Matricaria recutita L. were initiated from leaves and cultured on LINSMAIER‐SKOOG culture medium supplemented with 0.01 mg · 1−1 IAA or 3.00 mg · 1−1 2, 4‐D for three years. The relationship between mitotic activity and growth of calli was studied. The time at which mitotic activity began in both cultures was different. In the callus culture cultivated on the medium with IAA the maximum mitotic activity was observed on the 14th to 17th day of subculture. In the one cultivated on the medium with 2,4‐D, the increase of mitotic activity was observed earlier and corresponded with the beginning of exponential growth. In addition of total mitotic activity individual mitotic phases have also been evaluated. Most mitotically active cells in both cultures were in prophase. Their courses were similar to those of total mitotic activity. Metaphase and telophase stages were present in low frequency. Anaphase occured rarely. The functional dependences of mitotic activity and growth were characterized by appropriate mathematical models.
The controlled porous glass (CPG) with reactive epoxy groups as support for affinity chromatography. II. Modified CPG as support of substrates or coenzyme of glucose oxidase (GOD) for its purification and immobilization
Authors: Rogalski J. , Dawidowicz A. , Fiedurek J. , Leonowicz A. 
Published: December 2004

AbstractControlled porosity glasses (CPG) are materials very widely employed as supports for chromatography and biotechnology. In this paper CPG with epoxy groups have been applied as carrier of FAD, glucose and 2‐deoxy‐D‐glucose. Glucose oxidase (GOD) was highly purified on these sorbents. The purified fraction of GOD was also immobilized on the activated CPG. The presented results suggest the higher stability of immobilized form of this enzyme in relation to the native enzyme.
A new procedure of a two‐step cultivation of microorganisms. Part II. Application to the procedure of SCP‐production on the basis of sucrose
Authors: Teich W. , Otto G. , Bergmann H. , Pätz R. 
Published: December 2004

AbstractThe two‐step cultivation of microoganisms described in part I of this series will be explained by referring to its application to the production of SCP on the basis of sucrose/molasses as carbon sources. The inactivation of the yeast Candida utilis is carried out thermally, and the specific death rate was determined to be between 119 × 10−4 s−1, and 324 × 10−4 s−1, respectively. With this new procedure the apparent productivity could be increased by 96.6%, the yield coefficient of molasses increased by 5.8% and of sucrose by 12.9%. The crude protein content of the product in the case of sucrose rose by 104%. The variability of process design is demonstrated.
Continuous culture models with intermediates
Authors: Petrova T. A. , Ivanitskaya J. G. , Smirnova G. R. 
Published: December 2004

AbstractThe number of stability of steady states of minimal structured models are determined theoretically. Regulation of two “bottle‐necks” of cell metabilism by extracellular or intracellular or intracellular intermediates is suggested. The mechanisms of this regulation include substrate and product feed‐forward inhibition as well as feedback product control. The most complex system behaviour is obtained in models with feed‐forward intermediate inhibition. In particular these models exhibit multistability and two limit cycles.The maximum number of steady states decreases from five to four when the extracellular intermediate is changed by the intracellular one. The number of non‐zero steady states is changed from four to two.The relevant features of phase‐portrait appear to be independent of the choice of reaction rates. Therefore our results are suitable for a large group of the third order modles. The possibility to verify the theoretical predictions experimentally is also discussed.
Influence of acid phosphatase activity on the saccharification of potato maltodextrins by aspergillus niger glucoamylase
Authors: Żyła K. 
Published: December 2004

AbstractA preparation of Aspergillus niger acid phosphatase, which had the temperature optimum 60°C, pH optimum 1.8–3.0; good stability at pH 4–5, the ability to hydrolyze glucose‐6‐phosphate at a high rate, and substantial lack of glucogenic activities, was used simultaneously with a glucoamylase in order to learn its influence on the saccharification of potato maltodextrins.The addition of the acid phosphatase activity in amounts that gave the 50 fold increase, as compared to phosphatase activity which naturally occurs in the glucoamylase (GA) preparation ‘AMG‐200’, was found to influence on the DE level, mainly at the high substrate concentration (40% d.s.) and low glucoamylase dosage (60–100 GAU/kg d.s.). It may also be possible, when using the acid phosphatase addition, to shorten the saccharification time.
Plant cell cultivation as a biotechnological method
Authors: Schmauder H.‐P. , Doebel P. 
Published: December 2004

AbstractAn overview is given about some aspects of history, principles and application of plant cell and tissue cultivation. The main topics of application discussed in the paper are aspects of plant propagation, plant breeding, techniques for in vitro cultivation, in vitro production of secondary plant products, biotransformations, application of immobilized cells as well as economic aspects of plant cell and tissue culture.
The effect of covalent immobilization on ethanol‐induced, leakage in saccharomyces cerevisiae
Authors: Jirků V. 
Published: December 2004

AbstractEthanol‐induced leakage of UV‐absorbing compounds from free and immobilized Saccharomyces cerevisiae cells was studied. The resistance of immobilized cells to this ethanol effect is accompanied with increased levels of phospholipids and sterols. These results suggest a positive role of whole cell immobilization in improving yeast ethanol tolerance.
On the inhibition of laccase by lower fatty acids
Authors: Kreuter Th. , Steudel A. , Pickert H. 
Published: December 2004

AbstractLaccase (E.C. 1.10.3.2) is slowly inhibited by lower fatty acids in a reversible reaction. The degree of inhibition depends on kind and concentration of the fatty acid, but not on the concentration of the enzyme itself. The degree of inhibition increases with the chain length of the fatty acids. The maximum inhibition was found with butyric acid.
Liquid film bioreactors for cell mass production
Authors: Nikolaev N. A. , Voyonov N. A. , Markov V. A. 
Published: December 2004

AbstractIn order to make heat and mass transfer processes in bioreactors more intensive, the turbulent liquid film flow which is proposed for realization in multitubular reactors has been developed. Experiments have been carried out in tubes with smooth and rough surfaces at cocurrent gas and liquid film downward flows with a view to determine the values of the mass transfer coefficients in turbulent liquid hold‐up in contact tubes. The liquid viscosity and REYNOLDS number are changing in a wide range (from 2000 to 60000).The results show that the maximum values of the mass transfer coefficients and an acceptable hold‐up can be obtained in tubes with rough surfaces at high REYNOLDS numbers of the liquid film. The results of culturing yeasts on hydrolyzate in a laboratory‐size liquid film fermenter are also presented.
A comparative study of industrial and local yeast isolates
Authors: Olasupo N. A. , Scott‐Emuakpor M. B. 
Published: December 2004

AbstractThe biochemical properties of yeasts isolated from sugary substrates such as nectar, plam wine and sugar cane and identified as strains of Saccharomyces carlsbergensis and Saccharomyces cerevisiae were compared with those of imported industrial yeasts.The results presented here show that local yeasts better convert glucose, maltose and sucrose sugars at refrigeration temperature of 8°C than the imported ones. Significant differences existed in the amount of ethanol produced by both, the local and imported yeasts. Whereas the imported brewer's yeast exhibited copper sulphate resistance varying from 3.0mM to 7.0mM, the local isolates gave copper sulphate resistance values ranging from 2.0 to 15.0mM. The local yeast isolates also grew and flocculated faster than the industrial yeasts.The results are discussed in relation to the problems of the brewing industry in Nigeria, a third world's country.
Acid proteinases production by humicola lutea cells immobilized in polyhydroxyethylmethacrylate gel
Authors: Aleksieva P. , Petricheva E. , Konstantinov Ch. , Robeva M. , Mutafov S. 
Published: December 2004

AbstractThe spores of Humicola lutea entrapped in polyhydroxyethylmethacrylate gel were precultivated in production medium for mycelial formation. The immobilized mycelium was reused in batch mode for acid proteinases production. The influence of precultivation time, initial inoculum gel volume, and gel particle size on the enzyme activity and proteinases production half‐life were studied. After 70 h precultivation of the entrapped spores (10 ml initial inoculum volume, 12–27 mm3 gel particle size) maximum proteinases activity of 100–140% (compared with free cells) was registered in 15 reaction cycles. Under the same condition the half‐life time was 18 cycles, while for the free cells it was 5 cycles. The main advantage of the polyhydroxyethylmethacylate immobilized H. lutea was the long acid proteinases production half‐life at a low concentration of outgrowing cells in the medium.
Recent advances in the knowledge of the metabolism of bacterial polyhydroxyalkanoic acids and potential impacts on the production of biodegradable thermoplastics
Authors: Steinbüchel A. 
Published: December 2004

AbstractBacteria are able to synthesize a wide variety of different thermoplastic polyhydroxyalkanoic acids (PHA). The physiology of PHA metabolism has been studied in most detail in the aerobic hydrogen bacterium Alcaligenes eutrophus. Strains of this bacterium are already used for the production of biodegradable polyesters on a technological scale. The current knowledge on the pathways for PHA synthesis, on the genes essential for PHA biosynthesis and on genes affecting the accumulation of PHA in this bacterium will be reviewed.
Production of propionic acid by microbiological way. Part 1. Influence of the initial sugars and product concentrations
Authors: Obaya M. C. , Ramos J. , Eng F. , Villa P. , Valdés E. , Martínez A. , González J. , Berovides E. , Williams I. , Chivas M. , Cuellar A. 
Published: December 2004

AbstractThe best yields and productivities of 0.38 g · g−1 and 0.35 g · l−1 h−1, respectively, for the propionic acid production in a batchsystem using sugar‐cane final molasses as carbon source were obtained when an initial TRS concentration of 50 g · l−1 was used.It was obvious that this process is severely inhibited by the acids produced and the most drastic effect (μ = 0) was at a TVA concentration near to 250 mmol · l−1, independently of the initial TRS concentration employed.A generalizated equation of noncompetitive inhibition was adjusted:

and kinetic inhibition constants for each initial TRS concentration studied were estimated.
Cellulolytic enzymes of the ligninolytic white‐rot fungus Phlebia radiata
Authors: Rogalski J. , Hatakka A. , Wojtaś‐Wasilewska M. , Leonowicz A. 
Published: December 2004

AbstractThe ligninolytic fungus Phlebia radiata growing in a low‐nitrogen medium with Avicel cellulose as the sole carbon source produced a full spectrum of celluloytic enzymes. Some properties of these enzymes were investigated during the growth of the fungal culture.
Control of the degree of hydrolysis of a protein modification with immobilized protease by the pH‐drop method
Authors: Ge S. J. , Zhang L. X. 
Published: December 2004

AbstractA mathematical model, DH = 1/k(10−2ΔpH − 1), between the pH‐drop (ΔpH) and degree of hydrolysis (DH) of an enzymatic modification of casein was developed to assess the DH in a packed‐bed column reactor by directly monitoring the pH value of the modified protein system. It was demonstrated that the linear DH range and the k value of the equation were dependent on the reactor type and the specificity of the proteolytic enzymes immobilized on chitin used in the present study, but no effect of the substrate casein concentration on the linear DH range was observed. Since DH and ΔpH values of the modified casein correlated with the flow rate in a packed‐bed column reactor, it was suggested that the DH value, in a considerably wide range of casein modification with a certain immobilized protease in a column reactor, could be controlled by adjusting the flow rate of the substrate and monitored by a pH‐meter. This relationship might be used as a basis for scale‐up and long‐term operation of enzymatic modification of proteins by immobilized protease in a column reactor.
Enantioselective esterification of butanol‐2 in an enzyme membrane reactor
Authors: Ceynowa J. , Sionkowska I. 
Published: December 2004

AbstractThe enzymatic esterification of octanoic acid with racemic butanol‐2 was investigated. Esterifications of the acid were performed in a forced flow enzyme membrane reactor. The used membrane was prepared by a phase inversion process in polyamide‐6 solution followed by the chemical immobilization of a lipase‐catalyst.Influences of water content and pH were estimated. Their optimum values are equal to 0.5% w/w and pH 8. The reaction rate (at 303 K) of 5.1 × 10−5 mol/h·cm2 of the membrane area, and at least 85% enantiomeric excess in the produced ester mixture were obtained.The activity of immobilized lipase in the membrane process is about two times higher than that of the native lipase in the esterification performed in a tank reactor.
Optimization of the fermentation of whey by Lactobacillus casei
Authors: Rincón J. , Fuertes J. , Moya A. , Monteagudo J. M. , Rodríguez L. 
Published: December 2004

AbstractOptimization studies have been carried out for the production of L‐lactic acid from the fermentation of whey by Lactobacillus casei. Two Statistical Designs, a full 24 Factorial Design and a full 32 Factorial Design, have been used to determine the most suitable values of the operational variables for obtaining the maximum lactic acid production rate. The variables selected for study were temperature, pH, lactose concentration, and inoculum concentration. Among them only temperature and pH were found to affect the response significantly. A second‐order polynomial empirical model relating both the response (lactic acid production rate) and the variables was formulated. The maximum acid production rate was found when the values of pH and temperature were 5.4 and 38°C, respectively. All conclusions are restricted to the experimental range studied.
Killer yeasts of Kluyveromyces and Hansenula genera with potential application in fermentation and therapy
Authors: Michalčáková S. , Sulo P. , Sláviková E. 
Published: December 2004

AbstractThe killing/immunity interactions among killer strains of the genera Kluyveromyces, Hansenula and Saccharomyces from the Czechoslovak Collection of Yeasts were studied with the aim to find the strains with broad specificity and killer activity targeted against a range of undesirable wild yeasts causing stuck fermentations. Among 49 tested Kluyveromyces strains, five strains were found, and among 55 Hansenula strains, ten yeast strains were found with activity against a sensitive strain of Saccharomyces. Hansenula mrakii CCY 38‐7‐1 and Hansenula saturnus var. subsufficiens CCY 38‐4‐2 showed exceptional activity against the wine contaminants, Zygosaccharomyces bailii, as well as against pathogenic Candida species within a broad range of pH 2.9–5.1. Their potential biotechnological application is discussed.
Expression of the 2,4‐D degrading plasmid pJP4 of Alcaligenes eutrophus in Rhizobium trifolii
Authors: Feng L. , Van Zwieten L. , Kennedy I. R. , Rolfe B. G. , Gartner E. 
Published: December 2004

AbstractThe 2,4‐dichlorophenoxy acetic acid (2,4‐D) degrading plasmid, pJP4, was transferred into Rhizobium trifolii ANU843 from its nature host Alcaligenes eutrophus JMP134 by conjugation. The ability to degrade 2,4‐D was expressed in the transconjugant ANU843p as shown by a total loss of UV‐absorbent compounds and by gas chromatographic analysis. However, the transconjugant was unable to grow on 2,4‐D alone. When the transconjugant strain ANU843p was inoculated onto white and subterranean clover plants in laboratory trials, the transconjugant retained the capacity of nodulation, but the nitrogen‐fixation activity was diminished, particularly in the case of subterranean clover. The plasmid in the transconjugant was stable in nodules for at least nine weeks after inoculation and could be of value in applications requiring the protection or removal of the 2,4‐D involving cometabolism with plant substrates.
The effects of some amino acids on growth and lipid production in Inonotus obliquus grown in vitro
Authors: Kahlos K. 
Published: December 2004

AbstractThe effect of the distribution of free and esterified fatty acids, including triterpenes and sterols, on the mycelial growth of the basidiomycete Inonotus obliquus (Pers. ex Fr.) Pilat in malt extract and solid supplemented mineral media was investigated. The amino acids DL‐alanine. DL‐aspartic acid, L‐glutamic acid, L‐leucine, L‐methionine, and L‐serine were added to the cultures at nitrogen concentrations of 0.1, 0.5 and 0.9 g/l, respectively. Differences in the average mycelial growth were distinct at concentrations of 0.5 g/l and 0.9 g/l. L‐Methionine had the highest inhibitory effect on growth. At all concentrations, the amino acids reduced the production of lanosterol. The other identified triterpenes were inotodiol, 3β,hydroxy‐lanosta‐8,24‐dien‐21‐al, 3β,21‐dihydroxy‐lanosta‐8,24‐diene, trametenolic acid, and ergosterol peroxide. The main fatty acids were either C 16:0 or C 18:2 both free or in glycerides.
Carbon requirements of Colletotrichum gloeosporioides PENZ
Authors: Madan M. 
Published: December 2004

AbstractMonosporic isolates of Colletotrichum gloeosporioides were made from Punica grantum and one suitable isolate was selected for further work on carbon nutrition. Preliminary experiments showed that a pH value of 5, a temperature of 32°C and a period of 14 days were optimum conditions for the growth of this pathogen.Out of 41 carbon compounds tested, the pathogen showed excellent growth on starch, maltose, melibiose, dextrose, sucrose, raffinose, and dulcitol; good on tartaric acid, mannose, galactose, fructose, mannitol, and castor oil; fair on inulin, isopropyl alcohol, coconut oil, and pectin; poor on sorbose, n‐butyl alcohol, arabionose, maleic acid, ethyl alcohol, succinic acid, citric acid, ribose, and malic acid, and no growth on the rest of the carbon compounds. In general, compounds which supported the best mycelial growth, yielded excellent or good sporulation of C. gloeosporioides and vice versa.
Modelling the aerobic degradation of toluene in a closed chemostat with and without a head space outlet
Authors: Löser C. , Ray P. 
Published: December 2004

AbstractThe microbial aerobic decontamination of waste waters contaminated with highly volatile pollutants was experimentally investigated in a closed chemostat in [1]. The experiments, using a previously isolated Pseudomonas strain, were carried out with synthetic waste water containing toluene and saturated with either nitrogen or oxygen. A model for the interpretation of the experimentally determined process behaviour has been derived in this study. A comparison of the process curves obtained by simulation (numerical solutions of the model equations) with the experimentally determined results confirmed the model concepts. The model analysis supplied equations describing the process in a steady state as a function of the technical process parameters. These equations were used to draw conclusions for the practical operation of waste‐water purification processes in closed chemostats.