Wyniki wyszukiwania - Biblioteka Nauki

1

Drobnoustroje zimnolubne i ich enzymy

100%

Fiedurek J. , Szczodrak J.

|

nr 1

17-30

EN

The main role that cold-adapted microorganisms can play at low temperature is biodegradation of organic matter. Some of these microorganisms are pathogenic for plants and animals. Cold-adapted microorganisms cause many problems in the storage of food products. They are also attractive biocatalysts for many biotechnological purposes, because of high activity at low temperatures and increased thermolability. The mechanism of thermal adaptation is insufficiently recognised. The most common adaptations of cold-adapted microorganisms are: elevated flexibility of their molecules, fatty acid composition of membrane lipids, protein conformation and functioning of enzymes. Undoubtedly, better knowledge on the physiology and genetics of cold-adapted microorganisms could be useful for enhancing their metabolic activity in natural environments or in the industry.

2

Optimization of conditions for intracellular glucose oxidase extraction from Aspergillus niger mycelium

100%

Fiedurek J. , Szczodrak J.

|

nr 2

3

Decomposition of specifically C-labelled phenols as models for lignin degradation by Aspergillus terreus

80%

Rogalski J. , Szczodrak J. , Ilczuk Z.

|

nr 1-2

4

Identification and characterization of the Trichoderma harzianum gene encoding alpha-1,3-glucanase involved in streptococcal mutan degradation

80%

Wiater A. , Janczarek M. , Pleszczynska M. , Szczodrak J.

|

nr 4

EN

α-1,3-Glucanases (mutanases) are currently of great interest due to their potential use in the field of dental care. These enzymes have been reported in several bacteria, yeasts and fungi, but up to now, characterization of this family of proteins has been relatively poor. In this study, we identify and characterize a mutanase gene from Trichoderma harzianum CCM F-340. Sequence analysis, on the nucleotide and amino acid levels reveals that this α-1,3-glucanase is highly homologous to α-1,3-glucanases from T. harzianum isolate CBS 243.71 and T. asperellum CECT 20539. T. harzianum CCM F-340 mutanase is a 634-aa residue protein with a calculated molecular mass of 67.65 kDa, composed of two distinct, highly conserved domains (a long N-terminal catalytic domain and a short C-terminal polysaccharide-binding domain) separated by a less conserved Pro-Ser-Thr-rich linker region. The mutanase gene was expressed in an E. coli BL21(DE3) host, under the transcriptional control of T7 promoter. The purified enzyme migrated as a band of about 68 kDa after SDS-polyacrylamide gel electrophoresis, which coincided with the predicted size based on the amino acid sequence. Our data indicate that this enzyme is highly conserved in Trichoderma and can be produced in active form in such heterologous expression system.

5

Intensification of dextranolytic activity of Penicillium notatum 1 by mutagenization

80%

Szczodrak J. , Fiedurek J. , Pleszczynska M.

|

nr 2

6

Isoglucose production from raw starchy materials based on a two-stage enzymatic system

80%

Gromada A. , Fiedurek J. , Szczodrak J.

|

nr 2

EN

A new low-cost glucoamylase preparation for liquefaction and saccharification of starchy raw materials in a one-stage system was developed and characterized. A non-purified biocatalyst with a glucoamylase activity of 3.11 U/mg, an α-amylase activity of 0.12 WU/mg and a protein content of 0.04 mg protein/mg was obtained from a shaken-flask culture of the strain Aspergillus niger C-IV-4. Factors influencing the enzymatic hydrolysis of starchy materials such as reaction time, temperature and enzyme and substrate concentration were standardized to maximize the yield of glucose syrup. Thus, a 90% conversion of 5% starch, a 67.5% conversion of 5% potato flour and a 55% conversion of 5% wheat flour to sweet syrups containing up to 87% glucose was reached in 3 h using 1.24 glucoamylase U/mg hydrolyzed substrate. The application of such glucoamylase preparation and a commercially immobilized glucose isomerase for the production of glucose-fructose syrup in a two-stage system resulted in high production of stable glucose/fructose blends with a fructose content of 50%. A high concentration of fructose in obtained sweet syrups was achieved when isomerization was perfonned both in a batch and repeated batch process.

7

Ocena aktywności biologicznej karboksymetylowanych pochodnych alfa-(1→3)-glukanów wyizolowanych z owocników uprawnych gatunków boczniaka (pleurotus)

61%

Wiater A. , Paduch R. , Prochniak K. , Pleszczynska M. , Siwulski M. , Bialas W. , Szczodrak J.

|

nr 1

PL

α-(1→3)-Glukany stanowią najmniej poznaną grupę polisacharydów budujących ścianę komórkową grzybów. Celem pracy była ocena aktywności biologicznej karboksymetylowanych pochodnych α-(1→3)-glukanów uzyskanych z owocników uprawnych gatunków rodzaju Pleurotus (P. citrinopileatus, P. djamor, P. erynii i P. precoce). Polisacharydy wyizolowane z owocników poddano analizom strukturalnym (FT-IR i ¹H NMR), w wyniku czego wykazano, że są one liniowymi α-(1→3)-glukanami. Po zastosowaniu metody karboksymetylacji nierozpuszczalne w wodzie α-(1→3)-glukany przeprowadzono w formy rozpuszczalne, tj. karboksymetyl-α-(1→3)-glukany (KM-α-(1→3)-glukany). Następnie analizowano ich wpływ na żywotność komórek prawidłowych CCD 841 CoTr (ludzkie komórki nabłonka jelita grubego) i CCD-18Co (miofibroblasty jelitowe) oraz komórek nowotworowych HeLa (ludzki rak szyjki macicy). Wykonano analizy aktywności metabolicznej i toksyczności (MTT i NR) oraz zdolności do redukcji wolnych rodników (DPPH). Wykazano, że żywotność komórek nowotworowych była najsilniej redukowana przez KM-α-(1→3)-glukan otrzymany z owocników P. citrinopileatus. Z kolei metodą NR wykazano, że wszystkie badane KM-α-glukany w całym zakresie stężeń powodowały statystycznie istotny wzrost żywotności komórek prawidłowych (CCD 841 CoTr i CCD-18Co). Badane KM-α-glukany nie wykazywały aktywności zmierzającej do redukcji wolnych rodników tlenowych. Na podstawie analizy wyników różnicowego barwienia fluorescencyjnego stwierdzono, że KM-α-glukan z owocników P. citrinopileatus zaburza integralność błony komórek nowotworowych. Z kolei barwienie fluorescencyjne filamentów F-aktynowych (F-aktyny) wykazało, że nie wpływał on destrukcyjnie na cytoszkielet badanych komórek.

EN

α-(1→3)-Glucans constitute the least known group of polysaccharides that make up the fungal cell wall. The objective of the study was to assess the biological activity of carboxymethylated derivatives of α-(1→3)-glucans extracted from fruiting bodies of the cultivated species of Pleurotus (P. citrinopileatus, P. djamor, P. erynii, and P. precoce) genus. The polysaccharides extracted from the fruiting bodies were structurally analyzed (using FT-IR and ¹H NMR) and, based on the analysis results, it was proved that they were linear α-(1→3)-glucans. With the use of a carboxymethylation method, the water-insoluble α-(1→3)-glucans were converted into soluble forms, i.e. carboxymethyl-α-(1→3)-glucans (KM-α-(1→3)-glucans). Next, their effect was investigated on the viability of normal CCD 841 CoTr cells (normal human colonic epithelial cells), CCD-18Co (intestinal myofibroblasts), and HeLa tumour cells (human cervical cancer). The metabolic activity, toxicity (MTT and NR), and free radical scavenging ability (DPPH) were analyzed. It was shown that the effect of KM-α-(1→3)-glucan derived from the P. citrinopileatus fruiting bodies was the strongest as regards the reduction of the cancer cell viability. Then, the NR method used showed that all the tested KM-α-(1→3)-glucans within the entire concentration range caused the viability of normal cells (CCD 841 CoTr and CCD-18Co) to increase statistically significantly. The KM-α-glucans analyzed did not exhibit any free oxygen radical reduction activity. Based on the results of the differential fluorescent staining analysis, it was confirmed that the KM-α-glucan from fruiting bodies of P. citrinopileatus disturbed the membrane integrity of tumour cells. On the other hand, the fluorescent staining of the F-actin filaments proved that this KM-α-glucan did not have any destructive effect on the cytoskeleton of the cells studied.