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Biomedical subjects

J Rogalski

Publications and source records attributed to J Rogalski.

18 recordsLinked to original sources
PubMed2005

Manganese peroxidase production in submerged cultures by free and immobilized mycelia of Nematoloma frowardii.

The agaric basidiomycete Nematoloma frowardii has been suggested as a good alternative for production of the extracellular ligninolytic enzyme, manganese-dependent peroxidase (MnP). Some cultural and environmental factors influencing the enzymatic activity in shaken flasks and aerated fermenter cultures were evaluated to improve the yields of the process. A low nitrogen medium (1.36 mM N added as ammonium tartrate), containing 16 g/l glucose (C/N ratio=65.3), 2mM Mn2+ and inoculated with immobilized polyurethane foam mycelium, made it possible to obtain a MnP yield of 2304 nkat/l in 8 days. Under these operational conditions, the enzyme productivity in the immobilized cells of N. frowardii was 1.4 times higher than that obtained with the free fungus. In the procedure with the reusable immobilized mycelium (semi-continuous culture) as many as three subsequent 10 day batches could be fermented by using the same carrier with no loss of MnP activity.

Basidiomycota↗
PubMed2002

Influence of aromatic compounds on biodegradation of [14C]-labeled xylan and mannan by the white-rot fungus Phlebia radiata.

Radiolabeled [14C]arabinoxylan from wheat meal and [14C]galactoglucomannan from red clover meal were prepared by using 14CO2 as a precursor. Twice as much mannan was mineralized than xylan after 14 days of incubation with Phlebia radiata. Low-molecular-weight phenolic compounds structurally related to lignin increased during mineralization of both hemicellulose fractions. Veratryl alcohol increased degradation of arabinoxylan by approximately 28.5%, whereas veratric acid increased it by only 9.0%. Vanillic acid and ferulic acid also stimulated degradation by 16.6% and 34.7%, respectively. Veratryl alcohol and ferulic acid increased degradation of galactoglucomannan by approximately 75%. Veratraldehyde in both cases repressed the degradation process (23.6% arabinoxylan, 43.8% galactoglucomannan). These results indicate that the degradation of hemicelluloses, e.g., xylan and mannan, by P. radiata is enhanced by addition of aromatic compounds.

Benzaldehydes↗
PubMed2001

Fungal laccase: properties and activity on lignin.

The sources of ligninocellulose that occur in various forms in nature are so vast that they can only be compared to those of water. The results of several, more recent experiments showed that laccase probably possesses the big ability for "lignin-barrier" breakdown of ligninocellulose. The degradation of this compound is currently understood as an enzymatic process mediated by small molecules, therefore, this review will focus on the role of these mediators and radicals working in concert with enzymes. The fungi having a versatile machinery of enzymes are able to attack directly the "lignin-barrier" or can use a multienzyme system including "feed-back" type enzymes allowing for simultaneous transformation of lignin and carbohydrate compounds.

Basidiomycota↗
PubMed2001

Production of lignolytic and feed-back type enzymes by Phlebia radiata on different media.

Low molecular-weight compounds, structurally related to lignin, increase the production of laccase, lignin peroxidase, manganese dependent peroxidase, and feed-back type enzymes such as glucose oxidase, cellobioso-quinone oxidoreductase, and glyoxal oxidase in the culture of the white rot fungus Phlebia radiata growing on different carbon sources.

Alcohol Oxidoreductases↗
PubMed2001

Purification and characterization of two endo-1,4-beta-xylanases and a 3-xylosidase from phlebia radiata.

Two different endo-1,4-beta-xylanases, designated XA-1 and XA-2, and one beta-xylosidase (XD-1) have been purified by column chromatography to apparent homogeneity from the extracellular culture fluid of Phlebia radiata grown on wheat bran. The molecular masses of XA- 1, XA-2 and XD-1 were 18.6, 15.8 kDa, and 27 kDa, respectively. The isoelectric points for the xylanases were 6.7 and 4.1 and for the xylosidase - 5.9. The Km and Vmax values with larchwood xylan as substrate were 4.86 mg ml(-1) and 0.17 micromol min(-1) mg(-1) for XA-1; 2.7 mg ml(-1) and 3.91 micromol min(-1) mg(-1) for XA-2, whereas with pNPK as a substrate the Km and Vmax for XD-1 was 1.28 mM and 7.41 micromol min(-1) mg(-1). All the above enzymes are glycoproteins and the carbohydrate contents are for- XA-1 and XA-2 (6.70%, 3.58%) and for XD-1 (12.8%). Endoxylanase XA-1 and XA-2 were not able to release arabinose from rye arabinoxylan and birch xylan. Both enzymes were endo-acting, as revealed by their hydrolysis product profiles on xylan substrates.

Arabinose↗
PubMed2000

Demethylation of [14C]-labelled veratric acid and oxidation of methanol and formaldehyde by the white-rot fungus Phlebia radiata.

Veratric acids 14C-labelled in carboxyl group, 3-OCH3, 4-OCH3, or aromatic ring together with unlabelled veratric acid were supplemented in the cultures of the white-rot fungus Phlebia radiata. The effect of various carbon sources on the release of 14CO2 was studied. Veratric acid was readily decarboxylated, maximally already on day 1 from the addition of [14COOH]-veratric acid. High amounts (4%) of glucose slightly repressed the decarboxylation. In medium supplemented with cellulose the methoxyl group in position 4 was much more readily mineralized to CO2 than the group in position 3. The maximum evolution was achieved on day 5, two days from the addition. Cellulose did not repress methanol oxidation but repression of methanol oxidation by glucose was detected in media supplemented with [O14CH3]-veratric acids and 14CH3OH. However, glucose did not repress oxidation of H14CHO. The apparent uptake of 14C by fungal mycelium, especially from methoxyl groups, but also from the aromatic ring, may partially be due to the strong slime formation observed in cellobiose medium. Also in cellobiose medium apparent uptake of 14C from 14C-labelled methoxyl groups was observed.

Carbon Dioxide↗
PubMed1998

Purification of extracellular catalase from Aspergillus niger.

The extracellular catalase (EC 1.11.1.6) produced by Aspergillus niger culture in 5-liter fermentor was isolated and purified by ion-exchange chromatography on DEAE Sepharose (fast flow) column, hydrophobic interaction on phenyl-Sepharose column and chromatofocusing on PBE 94 column. Some physico-chemical properties of two purified catalase forms were also determined (molecular weight, isolelectric point, polysaccharides contents, Km, and Ea).

Aspergillus niger↗
PubMed1998

The preparation of specific sorbents with polyclonal antibodies as a ligand for purification of human antithrombin III.

Antithrombin III (AT III) is a serine protease inhibitor active against thrombin, factor X and factor VII. Major hematolytic abnormalities such as disseminated intravascular closing, coagulative vein inflammation, embolism in lungs or brain etc. frequently occur when the level of AT III is low. As a drug AT III is separated from blood preparations by bioselective sorption on sorbents containing heparine as a complementary ligand interacting with AT III molecules. The present paper describes the preparation procedures and the properties of sorbents with chemically bonded AT III antigen. The chromatographic ability of the prepared sorbents to separate AT III from human plasma are discussed in relation to the bonding procedure which was used for AT III antigen immobilization.

Animals↗
PubMed1996

Co-operation processes in dynamic environment management: evolution through training experienced pilots in flying a highly automated aircraft.

Dynamic environment management (process control, aircraft piloting, etc.) increasingly implies collective work components. Pragmatic purposes as well as epistemological interests raise important questions on collective activities at work. In particular, linked to the technological evolution in flight management, the role of the 'collective fact' appears as a key point in reliability. Beyond the development of individual competencies, the quality of the 'distributed' crew activity has to be questioned. This paper presents an empirical study about how experienced pilots co-ordinate their information and actions during the last period of training on a highly automated cockpit. A task of disturbance management (engine fire during takeoff) is chosen as amplifying cognitive requirements. Analysis focuses on the transitions between the main task and the incident to be managed. Crew performance and co-operation between two pilots are compared in three occurrences of the same task: the results are coherent with the hypothesis of a parallel evolution of the crew performance and its internal co-operation, and show that prescribed explicit co-operation is more present on action than on information about the 'state of the world'. Methodological issues are discussed about the possible effects of the specific situation of training, and about the psychological meaning of the results.

Aerospace Medicine↗
PubMed1995

Seeds as natural matrices for immobilization of Aspergillus niger mycelium producing pectinases.

A simple method for the immobilization of Aspergillus niger mycelium producing polygalacturonase (PG) and pectinesterase (PE) is described. Fungal conidia were immobilized on wheat, rye, barley, peas, buckwheat and mustards seeds. Spongy mycelia overgrowing the seed surfaces on mineral medium with pectin produced extracellular PG and PE; the highest production was reached on the wheat carrier. Some of the variables influencing the enzymatic activity have been optimized. After every 24 h, a culture liquid with 6.8-7.8 U of PG ml-1 and 7.0-10.1 U of PE ml-1 was obtained. This procedure also made possible repeated batch enzyme production and, as many as eight subsequent 24-h batches could be fermented by using the same carrier without any loss of PG activity. The addition of sodium orthovanadate (1 mmol) into the medium with pectin caused a significant increase in PG and PE activity produced by free cells of A. niger (by 1.59-fold and 1.67-fold respectively), and only 0.47-fold of PG activity in case of the immobilized mycelium.

Aspergillus niger↗
PubMed1993

Analysing communication in complex distributed decision-making.

This paper analyses emergency tasks within the theoretical framework of dynamic environment management with distributed decision-making (DDM). Models of task and work organization are used to analyse verbal exchanges in order to infer collective strategies. A cross-analysis method serves to analyse communication from the standpoint of both semantics and structure of the exchanges. The findings of two empirical comparative studies show that invariants vs differences in the organization and the semantics of exchanges are associated with invariants vs differences in parameters of the situations themselves (initial state and final result of actions). Efficient strategies were linked with well-structured flow of communication and roles distribution.

Communication↗
PubMed1990

Formation and Action of Lignin-Modifying Enzymes in Cultures of Phlebia radiata Supplemented with Veratric Acid.

Transformation of veratric (3,4-dimethoxybenzoic) acid by the white rot fungus Phlebia radiata was studied to elucidate the role of ligninolytic, reductive, and demeth(ox)ylating enzymes. Under both air and a 100% O(2) atmosphere, with nitrogen limitation and glucose as a carbon source, reducing activity resulted in the accumulation of veratryl alcohol in the medium. When the fungus was cultivated under air, veratric acid caused a rapid increase in laccase (benzenediol:oxygen oxidoreductase; EC 1.10.3.2) production, which indicated that veratric acid was first demethylated, thus providing phenolic compounds for laccase. After a rapid decline in laccase activity, elevated lignin peroxidase (ligninase) activity and manganese-dependent peroxidase production were detected simultaneously with extracellular release of methanol. This indicated apparent demethoxylation. When the fungus was cultivated under a continuous 100% O(2) flow and in the presence of veratric acid, laccase production was markedly repressed, whereas production of lignin peroxidase and degradation of veratryl compounds were clearly enhanced. In all cultures, the increases in lignin peroxidase titers were directly related to veratryl alcohol accumulation. Evolution of CO(2) from 3-OCH(3)-and 4-OCH(3)-labeled veratric acids showed that the position of the methoxyl substituent in the aromatic ring only slightly affected demeth(ox)ylation activity. In both cases, more than 60% of the total C was converted to CO(2) under air in 4 weeks, and oxygen flux increased the degradation rate of the C-labeled veratric acids just as it did with unlabeled cultures.

Journal Article↗
PubMed1984

Cellulolytic activity of moulds. III. Enzymatic hydrolysis of cellulose by cellulase preparation from Aspergillus terreus F-413.

The strain Aspergillus terreus F-413 was used to obtain cellulolytic enzymes; it was cultivated on cellucotton by the submerged method in a 101 fermenter. The crude enzymatic preparation obtained from the post-culture liquid, containing small amounts of other enzymes besides active cellulases, was used for hydrolysis of several kinds of cellulose. The highest saccharification percentage was obtained with cellucotton and filter paper, while the lowest with lignocellulosic materials such as straw and sawdust. It was shown that cellulose pretreatment, both mechanical (grinding in a ball mill) and chemical (with alkali) distinctly increased the yield of enzymatic hydrolysis. In the obtained hydrolyzates the presence of glucose as the main product of cellulose decomposition was found.

Aspergillus↗
PubMed1984

Cellulolytic activity of moulds. IV. Evaluation of the utility of cellulosic wastes for biosynthesis of cellulases and xylanase by Aspergillus terreus F-413.

The value of various cellulosic wastes for the synthesis of cellulolytic enzymes by the mould Aspergillus terreus F-413 was determined in submerged culture. The best results were obtained by using beet pulp. The dynamics of their synthesis was observed during a 12-day culture on the medium most favourable for the synthesis of cellulases.

Aspergillus↗
PubMed1983

Cellulolytic activity of moulds. II. Various methods of precipitating and concentrating enzymes and their influence on the activity of cellulolytic preparation and xylanase of Aspergillus terreus F-413.

Complexes of cellulolytic enzymes and xylanase were precipitated and concentrated by various methods from post-culture liquids of Aspergillus terreus F-143, containing cellucotton as carbon source. The best results in regard to the specific activity of the preparations were obtained by precipitation of enzymes with acetone-denatured ethanol. Besides high cellulolytic and xylanase activity the crude enzyme preparation showed the presence of small amounts of amylase, protease and polygalacturonase.

Acetone↗
PubMed1981

Isolation and properties of elongation factor 1 from Saccharomyces cerevisiae.

Polypeptide elongation factor 1 was isolated from yeast postribosomal supernatant. The highly purified factor was resolved on Ultrogel AcA-44 into two complementary fractions. One of these fractions contained two different polypeptide chains corresponding to a Ts-like elongation factor EF-1 beta gamma. The other fraction represented the light form of the factor, designated EF-1 alpha, with a molecular weight of approximately 50,000. The obtained results indicate that EF-1 from lower eukaryotes is also composed of three distinct polypeptides.

Fungal Proteins↗
PubMedDate not supplied

Biodegradation of lignin by white rot fungi.

A review is presented related to the biochemistry of lignocellulose transformation. The biodegradation of wood constituents is currently understood as a multienzymatic process with the mediation of small molecules; therefore, this review will focus on the roles of these small molecular compounds and radicals working in concert with enzymes. Wood rotting basidiomycetous fungi penetrate wood and lead to more easily metabolized, carbohydrate constituents of the complex. Having a versatile machinery of enzymes, the white rot fungi are able to attack directly the "lignin barrier." They also use a multienzyme system including so-called "feed back" type enzymes, allowing for simultaneous transformation of both lignin and cellulose. These enzymes may function separately or cooperatively.

Basidiomycota↗