Wyniki wyszukiwania - Biblioteka Nauki

1

Immobilization of Catalase via Adsorption onto Natural and Modified Montmorillanit Analsim-Clay

100%

Alkan S. , Gür T. , Gür A. , Uruc H. , Demir H.

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2009

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tom Vol. 83, nr 12

2089-2095

EN

Immobilization of the enzyme catalase on natural and modified montmorillanit analsimclays was investigated using a batch system. Such an immobilization does not result in enzyme in activation and constitutes a valuable method for immobilizing catalase at high ionic strength. In the immobilization process, the effect of pH, ionic strength and reaction temperature were chosen as parameters. Further more the optimization of immobilization conditions were studied using data obtained from experimental results. For the free catalase and three different immobilized catalase enzymes, the optimum pH values 8, 7, 7 and 8; reaction temperature 30°C; ionic strength 0.25 M were found. It was determined that enzyme activity for enzyme supported by natural clay was 73.3 percent, when it was retained during the storage at 4°C for a period of 60 days. It was observed that storage and operational stabilities of the enzyme in creased with immobilization. The results obtained show that montmorillanit analsim-clay is valuable and favour able support the simple adsorption of enzymes.

2

Effect of Cu(II) Coordination Compounds on the Activity of Antioxidant Enzymes Catalase and Superoxide Dismutase in Patients with Colorectal Cancer

100%

Kubiak K. , Malinowska K. , Langer E. , Dziki Ł. , Dziki A. , Majsterek I.

Polish Journal of Surgery

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2011

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tom 83

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nr 3

155-160

EN

Colorectal cancer (CRC) is a serious medical and economical problem of our times. It is the most common gastrointestinal cancer in the world. In Poland, the treatment and detection of CRC are poorly developed and the pathogenesis is still unclear. One hypothesis suggests a role of reactive oxygen species (ROS) in the pathogenesis of CRC. Experimental studies in recent years confirm the participation of ROS in the initiation and promotion of CRC.The aim of the study was to examine the effect of the following coordination compounds coordination compounds: dinitrate (V) tetra(3,4,5-trimethyl-N1-pyrazole-κN2) copper(II), dichloro di(3,4,5-trimethyl-N1-pyrazole-κN2) copper(II), dinitrate (V) di(1,4,5-trimethyl-N1-pyrazole-κN2) copper(II), dichloro di(1,3,4,5-tetramethyl-N1-pyrazole-κN2) copper(II) on the activity of antioxidant enzymes superoxide dismutase (SOD, ZnCu-SOD) and catalase (CAT) in a group of patients with colorectal cancer (CRC) and in the control group consisting of patients with minor gastrointestinal complaints.Material and methods. The study was conducted in 20 patients diagnosed with colorectal cancer at the age of 66.5±10.2 years (10 men and 10 women) versus the control group of 20 people (10 men and 10 women) aged 57.89±17.10 years without cancer lesions in the biological material - hemolysate prepared in a proportion of 1ml of water per 1 ml of blood. CAT activity was measured by the Beers method (1952), while SOD activity was measured by the Misra and Fridovich method (1972).Results. We found that patients with CRC showed a statistically significant decrease of SOD and CAT activity (CAT - 12,75±1.97 U/g Hb, SOD - 1111.52±155.52 U/g Hb) in comparison with the control group (CAT - 19.65±2,17 U/g Hb, SOD - 2046.26±507.22 U/g Hb). Simultaneously, we observed that the investigated coordination compounds of Cu(II) significantly increased the antioxidant activity of CAT and SOD in patients with CRC (mean: CAT 25.23±4.86 U/g Hb, SOD - 3075.96±940.20 U/g Hb).Conclusions. Patients with colorectal cancer are characterized by reduced activity of antioxidant enzymes catalase and superoxide dismutase which suggests impaired antioxidant barrier. Therefore, coordination compounds of Cu (II), which enhance the activity of CAT and SOD, may prove useful in the prevention and treatment of colorectal cancer.

3

Biochemical characterization of a catalase from Vibrio vulnificus, a pathogen that causes gastroenteritis

88%

Pei J. , Wang H. , Wu L. , Xia S. , Xu C. , Zheng B. , Li T. , Jiang Y.

Acta Biochimica Polonica

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2017

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tom 64

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nr 3

543-549

EN

Vibrio vulnificus is a virulent human pathogen causing gastroenteritis and possibly life threatening septicemia in patients. Most V. vulnificus are catalase positive and can deactivate peroxides, thus allowing them to survive within the host. In the study presented here, a catalase from V. vulnificus (CAT-Vv) was purified to homogeneity after expression in Escherichia coli. The kinetics and function of CAT-Vv were examined. CAT-Vv catalyzed the reduction of H2O2 at an optimal pH of 7.5 and temperature of 35°C. The Vmax and Km values were 65.8±1.2 U/mg and 10.5±0.7 mM for H2O2, respectively. Mutational analysis suggests that amino acids involved in heme binding play a key role in the catalysis. Quantitative reverse transcription-PCR revealed that in V. vulnificus, transcription of CAT-Vv was upregulated by low salinity, heat, and oxidative stresses. This research gives new clues to help inhibit the growth of, and infection by V. vulnificus.

4

Thermal stability for the effective use of commercial catalase

88%

Miłek J. , Wójcik M. , Verschelde W.

Polish Journal of Chemical Technology

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2014

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tom 16

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nr 4

75-79

EN

Catalase with the commercial catalase name Terminox Ultra is widely used in the textile industry in bleaching processes. This enzyme is used to catalyse the decomposition of residual hydrogen peroxide into oxygen and water. In this study catalase was kept for about 30 hours in water baths in a temperature range from 35 to 70°C. For the first time, the kinetics of thermal deactivation of this enzyme was examined using an oxygen electrode. Stability of the enzyme depends strongly on temperature and its half-life times are 0.0014 h and 7.6 h, at 35 and 70°C, respectively.

5

Cadmium-induced changes in antioxidant enzymes in suspension culture of soybean cells.

75%

Sobkowiak R. , Rymer K. , Rucińska R. , Deckert J.

Acta Biochimica Polonica

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2004

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tom 51

|

nr 1

219-222

EN

Cadmium (Cd), similarly to other heavy metals, inhibits plant growth. We have recently showed that Cd2+ either stimulates (1-4 μM) or inhibits (ł 6 μM) growth of soybean (Glycine max L.) cells in suspension culture (Sobkowiak & Deckert, 2003, Plant Physiol Biochem. 41: 767-72). Here, soybean cell suspension cultures were treated with various concentrations of Cd2+ (1-10 μM) and the following enzymes were analyzed by native electrophoresis: superoxide dismutase (SOD), catalase (CAT), peroxidase (POX) and ascorbate peroxidase (APOX). We found a significant correlation between the cadmium-induced changes of soybean cell culture growth and the isoenzyme pattern of the antioxidant enzymes. The results suggest that inhibition of growth and modification of antioxidant defense reactions appear in soybean cells when Cd2+ concentration in culture medium increases only slightly, from 4 to 6 μM.

6

Aktywność katalazy i stężenie żelaza w nasieniu ludzkim

75%

Kasperczyk A. , Horak S.

Annales Academiae Medicae Silesiensis

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2013

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tom 67

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nr 2

112-116

EN

INTRODUCTION The activity of antioxidant system enzymes in human semen might be age dependent, thus the quality of it may get worse. The aim of this study was to investigate the correlation between the age, catalase activity and iron concentration in seminal plasma and the influence of these factors on the quality of semen. MATERIALS AND METHODS Normospermic semen samples were obtained from 63 men (range, 22–37 years) and divided in two age groups: under 33 (group I) and over 33 years old (group II). The semen parameters, catalase activity and iron concentration were determined in seminal plasma. RESULTS We observed that in group II the iron concentration in seminal plasma increased but sperm motility (especially linear progressive motility) dropped with age. A lower semen volume showed a significant increase in catalase activity as well as iron concentration. Increasing catalase activity showed a significant positive relationship with better sperm quality. We found positive correlations between catalase activity and iron concentration. CONCLUSION Catalase has a protective effect on sperm cell membranes. Iron concentration in seminal plasma rises in an age dependent manner which may contribute to sperm cells damage.

PL

WSTĘP Aktywność enzymów wchodzących w skład układu antyoksydacyjego nasienia może w miarę starzenia organizmu ulec osłabieniu, co może być przyczyną obniżenia zdolności zapładniającej nasienia. Celem pracy było ustalenie, czy wraz z wiekiem zmieniają się aktywność katalazy i stężenie żelaza w nasieniu ludzkim i jak zmiany te wpływają na jego jakość. MATERIAŁ I METODY Materiał badany stanowiło nasienie o prawidłowej morfologii pobrane od 63 mężczyzn w wieku od 28 do 37 lat (grupa I – do 33 roku życia; grupa II – powyżej 33 roku życia). Wykonano badanie morfologiczne nasienia, oznaczono aktywność katalazy i stężenie żelaza w plazmie nasiennej. WYNIKI Stwierdzono, że wraz z wiekiem obniża się liczba plemników ruchliwych, zwłaszcza o ruchu linearnym, natomiast zwiększa się stężenie żelaza. Wraz ze spadkiem objętości nasienia wzrasta aktywność katalazy i stężenie żelaza, zaś wzrostowi aktywności katalazy towarzyszy wzrost stężenia ruchliwych plemników. Wykazano ponadto dodatnią korelację pomiędzy aktywnością katalazy a stężeniem żelaza. WNIOSKI Katalaza wykazuje działanie ochronne na błonę komórkową plemników. Stężenie żelaza w plazmie nasienia wzrasta u mężczyzn wraz z wiekiem, co może przyczyniać się do uszkodzenia plemników.

7

Physiological and Biochemical Responses of Fern Nephrolepis Biserrata (Sw.) Schott. to Coccus Hesperidum L. Infestation

75%

Golan K. , Rubinowska K. , Górska-Drabik E.

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8

Antioxidant status in erythrocytes of cystic fibrosis children.

75%

Laskowska-Klita T. , Chełchowska M.

Acta Biochimica Polonica

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2001

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tom 48

|

nr 1

283-285

EN

Activities of superoxide dismutase, catalase and glutathione peroxidase in erythrocytes of cystic fibrosis children were studied in order to estimate the severity of their deficiency. Our results point to increased susceptibility of erythrocytes of cystic fibrosis subjects to oxidative injury and indicate that the antioxidant status of patients should be carefully monitored.

9

Effect of stress on the life span of the yeast Saccharomyces cerevisiae.

75%

Święciło A. , Krawiec Z. , Wawryn J. , Bartosz G. , Biliński T.

Acta Biochimica Polonica

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2000

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tom 47

|

nr 2

355-364

EN

A correlation is known to exist in yeast and other organisms between the cellular resistance to stress and the life span. The aim of this study was to examine whether stress treatment does affect the generative life span of yeast cells. Both heat shock (38°C, 30 min) and osmotic stress (0.3 M NaCl, 1 h) applied cyclically were found to increase the mean and maximum life span of Saccharomyces cerevisiae. Both effects were more pronounced in superoxide dismutase-deficient yeast strains (up to 50% prolongation of mean life span and up to 30% prolongation of maximum life span) than in their wild-type counterparts. These data point to the importance of the antioxidant barrier in the stress-induced prolongation of yeast life span.

10

Differential response of antioxidant enzymes to cadmium stress in tolerant and sensitive cell line of cucumber (Cucumis sativus L.)

75%

Gzyl J. , Rymer K. , Gwóźdź E.

Acta Biochimica Polonica

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2009

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tom 56

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nr 4

723-727

EN

Previously, a stable cell suspension of cucumber tolerant to 100 µM CdCl2 was obtained (Gzyl & Gwóźdź, 2005, Plant Cell Tissue Organ Cult 80: 59-67). In this study, the relationship between the activity of antioxidant enzymes and cadmium tolerance of cucumber cells was analyzed. A cadmium-sensitive and the cadmium-tolerant cell lines were exposed to 100 µM and 200 µM CdCl2 and the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APOX) and guaiacol peroxidase (POX) were determined. In the sensitive cell line, a decrease of total activity of SOD and POX was observed, whereas the activity of CAT and APOX significantly increased in metal-supplemented medium. By contrast, in the tolerant cells, the total activity of antioxidant enzymes decreased (SOD, CAT) or was maintained at approximately the same level (APOX, POX). Moreover, a different pattern of isoenzyme activity was observed in the tolerant and sensitive cells. These results suggest that an enhanced activity of antioxidant enzymes is not directly involved in the increased tolerance to cadmium of the selected cucumber cell line.

11

A kinetic method for para-nitrophenol determination based on its inhibitory effect on the catalatic reaction of catalase

75%

Mureşanu C. , Copolovici L. , Pogącean F.

Open Chemistry

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2005

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tom 3

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nr 4

592-604

EN

The inhibitory effect of para-nitrophenol on the catalytic reaction of catalase was investigated. Michaelis-Menten kinetic parameters were determined from Lineweaver-Burk plots obtained in the absence or in the presence of the inhibitor. The inhibitor pattern, revealed by the Lineweaver-Burk plots, suggested a fully mixed inhibition mechanism. Spectrophotometric monitoring of the indicator reaction: $$H_2 O_2 \xrightarrow{{catalase,para - nitrophenol}}H_2 O + \tfrac{1}{2}O_2 $$ in conjunction with initial rate measurements was employed for the kinetic determination of the inhibitor. Calibration plots of initial rate vs. para-nitrophenol concentration were linear in the concentration range 0.9·10−5–2.5·10−5 mol/L and the detection limit was 3·10−6 mol/L (417 μg/L) para-nitrophenol. Interferences from other phenolic compounds like orto-cresole, meta-and orto-nitrophenol were observed.

12

AMELIORATIVE EFFECTS OF DIMETHYL FUMARATE IN ACUTE AND CHRONIC MURINE MODELS OF DEPRESSION

75%

Iniaghe L. O. , Okpakpor E. E. , Edosuyi O. O. , Eseka E. O. , Nedozi O. I.

Acta Poloniae Pharmaceutica - Drug Research

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2018

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tom 75

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nr 6

1399-1407

EN

Depression, a major contributor to the global disease burden, occurs in both adults and children, and is associated with impaired antioxidant defense mechanisms. This study examined the effects of dimethyl fumarate (DMF), a fumaric acid ester with immunomodulatory, anti-inflammatory and antioxidant properties in murine models of depression. In the first phase of the study, mice were treated with the either the vehicle, 50 and 100 mg/kg DMF or 15 mg/kg imipramine and subjected to either the forced swim or tail suspension tests. Thereafter, mice were euthanized and levels of antioxidant markers in isolated brain tissues were assayed. In the second phase of the study, mice were subjected to the chronic unpredictable mild stress regimen for four weeks and treated with the vehicle, DMF or imipramine in the last two weeks of the stress protocol. Forced swim and percentage sucrose preference tests were used for behavioural evaluations. Mice were sacrificed, brain levels of catalase, glutathione, thiobarbituric reactive acid substance and nitrite were quantified. Treatment with DMF significantly (p<0.05) reduced periods of immobility in both the forced swim and tail suspension tests following acute and chronic drug treatment and improved sucrose consumption after exposure to chronic unpredictable mild stress. DMF also significantly improved (p<0.05) levels of antioxidants (catalase and glutathione) while reducing prooxidant biomarkers (thiobarbituric reactive acid substance and nitrite levels) in the brain. DMF ameliorated depression in mice and augmented the antioxidant defense mechanism in the brains of mice subjected to chronic unpredictable mild stress.

13

Aktywność enzymatyczna katalazy oraz stężenie dialdehydu malonowego (TBARS) w krwinkach płytkowych eksponowanych na promieniowanie elektromagnetyczne o różnym kształcie

63%

Jankowski W. , Henrykowska G. , Dziedziczak-Buczyńska M. , Pacholski K. , Buczyński A.

Polish Hyperbaric Research

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2008

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tom Nr 2(23)

15-24

PL

Promieniowanie elektromagnetyczne jako czynnik środowiskowy działa na układy biologiczne w sposób wielotorowy, może wywoływac różnorodne efekty biologiczne, które do tej pory nie zostały w całosci poznane. W organizmie, różnorodne składniki i struktury komórkowe moga stanowić docelową tarczę działania promieniowania elektromagnetycznego. Dotyczy to również płytek krwi, które ze względu na swoją rolę w organizmie i skutki zaburzonej ich funkcji, stanowią interesujacy model badawczy. Celem pracy była ocena wpływu kształtu pola elektromagnetycznego (PEM) o niskiej częstotliwosci na aktywnosc enzymatyczną katalazy oraz stężenie dialdehydu malonowego w krwinkach płytkowych człowieka. Zawiesina ludzkich krwinek płytkowych była poddawana działaniu PEM o różnym kształcie, czestotliwosci 50 Hz i indukcji elektromagnetycznej 10 mT przez 15 i 30 minut. Zródłem PEM były cewki Helmholza ustawione na specjalnie skonstruowanym wsporniku, w którego wnętrzu umieszczano probówki z zawiesiną krwinek. Następnie były one poddawane działaniu okreslonego PEM. Pomiar aktywnosci enzymatycznej katalazy, wykazał jej wzrost w stosunku do wartości kontrolnych niezależnie od czasu ekspozycji i bez względu na kształt zastosowanego pola. Największe zmiany w stosunku do wartości wyjsciowych, obserwowano przy ekspozycji krwinek płytkowych na pole elektromagnetyczne o trójkątnym i prostokątnym przebiegu impulsu. Po 15 min. Oddziaływania promieniowania o kształcie trójkątnym, mediana aktywnosci enzymatycznej katalazy wzrosła z wartości wyjsciowych x=6,49 do x=9,25, a o kształcie prostokątnym do x=7,87. Po 30 min. napromieniowywania również odnotowano zwiekszoną aktywność enzymatyczną w stosunku do wartosci wyjściowych: o 48% (do x=9,63) przy polu elekromagnetycznym o kształcie trójkątnym i o 81% (do x=11,75) przy zastosowaniu prostokątnego impulsu pola. Stężenie dialdehydu malonowego w stosunku do wartosci kontrolnych wzrosło zarówno po 15 jak i po 30 minutach ekspozycji bez względu na kształt zastosowanego impulsu elektromagnetycznego. Największe przyrosty mediany stężenia obserwowano po 15 minutowej ekspozycji krwinek płytkowych na PEM o sinusoidalnym kształcie impulsu, z x=1,57 do x=4,12. Po 30 minutach napromieniowania największy wzrost mediany steżenia MDA zaobserwowano przy działaniu pola elektromagnetycznego o trójkątnym przebiegu impulsu, o 96% w stosunku do wartosci kontrolnych. Na podstawie uzyskanych wyników można stwierdzić, że badane PEM powoduje wzrost aktywności enzymatycznej katalazy jak również stężenia dialdehydu malonowego w krwinkach płytkowych. Poziom aktywności enzymu oraz stężenia TBARS w badanych komórkach zależy od kształtu użytego PEM.

EN

The aim of the study was to assess the influence of the shape of the electromagnetic field of low frequency on enzymatic activity of catalase and concentration of malondialdehyde in human blood platelets. The suspension of human blood platelets was subjected to the activity of the electromagnetic field of different shapes, the frequency of 50Hz and the electromagnetic induction of 10mT for 15 and 30 minutes. The Helmholtz coils were the source of the electromagnetic field. They were arranged on the specially prepared bracket, inside of which test tubes with the blood platelets suspension were put. Next, they were subjected to the activity of a specific electromagnetic field. The measurement of the enzymatic catalase activity showed an increase in comparison with the initial values regardless of the time of the exposure and regardless of the shape of the applied electromagnetic field. The greatest changes in comparison with the initial values were observed during the exposure of the blood platelets to the electromagnetic field of triangular and rectangular pulse oscillation. After exposure to the radiation of triangular form for 15 minutes, the median of the enzymatic catalase activity increases from the initial values x=6,49 to x=9,25, of the rectangular form to x=7,87. After 30 minutes of the radiation increased enzyme activity was observed in comparison to the initial values: 48% (to x=9,63) in case of triangular shape of pulse oscillation and 81% (to x=11,75) in case of the rectangular shape. The concentration of malondialdehyde in comparison to the initial values increased after 15 as well as 30 minutes of exposure, regardless of the shape of the applied electromagnetic field. The greatest increases were observed after 15 min. blood platelets exposure to electromagnetic field of sinusoid pulse oscillation , from x=1,57 to x=4,12. After 30 minutes of radiation, the greatest increase of the concentration of malondialdehyde was observed during the exposure to the electromagnetic field of triangular pulse oscillation, 96% in comparison to the initial values. Basing on the achieved results, it can be assumed that the investigated electromagnetic field causes the increase of enzymatic catalase activity and the concentration of malondialdehyde in blood platelets. The level of the enzyme activity and of the concentration of malondialdehyde in tested cells depends on the shape of the applied electromagnetic field.

14

Inhibitory effects of sodium benzoate on germination and growth seedling of radish Raphanus sativus L.

63%

Święciło A.

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2008

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tom Vol. 15, nr 3

245-251

EN

Derivatives of benzoic acid are produced on industrial scale and are used as preservatives in food, pharmaceutical and cosmetic industry. They also occur naturally in same berries and are intermediates of metabolic paths. In over-physiological doses they have a destructive effect on human body and other live organisms. The aim of Ibis study was to determine the influence of sodium benzoate on germination process of radish seeds Raphanus sativus L. The results that were obtained reveal that sodium benzoate in the concentration lower than 0.03 mol. dm-3 decreases the number of germinated seeds of radish. Seedlings obtained from these seeds were shorter than the seedlings in control and their roots were also reduced. No other pathomorphological features were observed. Sodium benzoate used in the concentration equal to or higher than 0.03 mol. dm-3 inhibits the germination process of radish seeds but it does not decrease the viability of germs of these seeds and does not change their catalase activity. The process of inhibiting germination can be reversed by removing Ibis substance from the environment.

PL

Pochodne kwasu benzoesowego produkowane na skalę przemysłową są wykorzystywane jako substancje konserwujące głównie w przemyśle spożywczym, farmaceutycznym i kosmetycznym. Występują one także w stanie naturalnym w niektórych owocach jagodowych oraz są intermediatami szlaków metabolicznych. W nie fizjologicznych dawkach działają szkodliwie na organizm człowieka i inne organizmy żywe. Celem niniejszej pracy było badanie wpływu benzoesanu sodu na proces kiełkowania nasion i wydłużania korzeni u rzodkiewki Raphanus sativus L. Uzyskane wyniki wskazują, że benzoesan sodu zastosowany w stężeniach mniejszych niż 0,03 mol. dm-3 obniża liczbę wykiełkowanych nasion rzodkiewki. Siewki uzyskane z tych nasion były mniejsze niż siewki kontrolne i charakteryzowały się skróceniem korzenia. Nie stwierdzono u nich innych cech patomorfologicznych. Benzoesan sodu zastosowany w stężeniu równym lub większym niż 0,03 mol. dm-3 hamuje proces kiełkowania nasion rzodkiewki, ale nie obniża żywotności zarodków tych nasion i nie zmienia ich aktywności katalazowej. Proces hamowania kiełkowania można odwrócić poprzez usunięcie tej substancji ze środowiska.

15

impact of UV mediated hydrogen peroxide on culturable bacteria in the surface microlayer of eutrophic lake

63%

Walczak M. , Swiontek Brzezinska M.

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2009

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tom Vol. 57, nr 3

547-554

EN

Hydrogen peroxide (H2O2) formation in surface waters is initiated by the absorption of sunlight by dissolved organic matter (DOM). The fraction of the DOM pool that interacts with sunlight, referred to as chromophoric dissolved organic matter, impacts the optical properties of surface waters. Second source of H2O2 is wet and dry deposition of photogenerated substance in the atmosphere and biological production. The study examined the concentration of hydrogen peroxide in water from the surface microlayer (SM) (<100 [my]m) and subsurface water (SSW) (25 cm) in the typical eutrophic (TOC 5-15 mg dm[^-3]; chlorophyll 5-26 [my]g dm[^-3], water transparency 0.6-1.0 m) lake as well as the impact of this compound on occurrence and survivorship of catalase-positive and catalase-negative bacteria isolated and cultured on the TSA medium (Difco). The experimental H2O2 concentrations ranged between 500-5000 nM. The concentration of H2O2 in analyzed water samples clearly increased in day-time hours and was different in May, July and October. The highest natural concentration of H2O2 (700 nM) was observed in SM water in summer in afternoon hours. During that period, 100% of bacterial populations found in SM water produced catalase. The experiments confirmed that environmental concentrations of H2O2 caused no considerable decrease in survivorship of culturable bacteria, while concentrations exceeding 1000 nM were lethal for the majority of catalasenegative bacteria, but not for catalase-positive bacteria.

16

Antioxidative defense to lead stress in subcellular compartments of pea root cells.

63%

Małecka A. , Jarmuszkiewicz W. , Tomaszewska B.

Acta Biochimica Polonica

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2001

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tom 48

|

nr 3

687-698

EN

Lead, similar to other heavy metals and abiotic factors, causes many unfavorable changes at the subcellular and molecular levels in plant cells. An increased level of superoxide anion in Pisum sativum root cells treated with 1 mM Pb(NO3)2 evidenced oxidative stress conditions. We found increased activities of enzymatic components of the antioxidative system (catalase and superoxide dismutase) in the cytosol, mitochondrial and peroxisomal fractions isolated from root cells of Pisum sativum grown in modified Hoagland medium in the presence of lead ions (0.5 or 1 mM). Two isoenzyme forms of superoxide dismutase (Cu,Zn-SOD and Mn-SOD) found in different subcellular compartments of pea roots were more active in Pb-treated plants than in control. Increased amount of alternative oxidase accompanied by an increased activity of this enzyme was found in mitochondria isolated from lead-treated roots. These results show that plants storing excessive amounts of lead in roots defend themselves against the harmful oxidative stress caused by this heavy metal.

17

Generation of ·OH initiated by interaction of Fe2+ and Cu+ with dioxygen; comparison with the Fenton chemistry.

63%

Urbański N. K. , Beręsewicz A.

Acta Biochimica Polonica

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2000

|

tom 47

|

nr 4

951-962

EN

Iron and copper toxicity has been presumed to involve the formation of hydroxyl radical (·OH) from H2O2 in the Fenton reaction. The aim of this study was to verify that Fe2+-O2 and Cu+-O2 chemistry is capable of generating ·OH in the quasi physiological environment of Krebs-Henseleit buffer (KH), and to compare the ability of the Fe2+-O2 system and of the Fenton system (Fe2+ + H2O2) to produce ·OH. The addition of Fe2+ and Cu+ (0-20 μM) to KH resulted in a concentration-dependent increase in ·OH formation, as measured by the salicylate method. While Fe3+ and Cu2+ (0-20 μM) did not result in ·OH formation, these ions mediated significant ·OH production in the presence of a number of reducing agents. The ·OH yield from the reaction mediated by Fe2+ was increased by exogenous Fe3+ and Cu2+ and was prevented by the deoxygenation of the buffer and reduced by superoxide dismutase, catalase, and desferrioxamine. Addition of 1 μM, 5 μM or 10 μM Fe2+ to a range of H2O2 concentrations (the Fenton system) resulted in a H2O2-concentration-dependent rise in ·OH formation. For each Fe2+ concentration tested, the ·OH yield doubled when the ratio [H2O2]:[Fe2+] was raised from zero to one. In conclusion: (i) Fe2+-O2 and Cu+-O2 chemistry is capable of promoting ·OH generation in the environment of oxygenated KH, in the absence of pre-existing superoxide and/or H2O2, and possibly through a mechanism initiated by the metal autoxidation; (ii) The process is enhanced by contaminating Fe3+ and Cu2+; (iii) In the presence of reducing agents also Fe3+ and Cu2+ promote the ·OH formation; (iv) Depending on the actual [H2O2]:[Fe2+] ratio, the efficiency of the Fe2+-O2 chemistry to generate ·OH is greater than or, at best, equal to that of the Fe2+-driven Fenton reaction.

18

Reactions of Pseudomonas aeruginosa pyocyanin with reduced glutathione

63%

Cheluvappa R. , Shimmon R. , Dawson M. , Hilmer S. N. , Le Couteur D. G.

Acta Biochimica Polonica

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2008

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tom 55

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nr 3

571-580

EN

Pseudomonas aeruginosa is the most common cause of chronic and recurrent lung infections in patients with cystic fibrosis (CF) whose sputa contain copious quantities of P. aeruginosa toxin, pyocyanin. Pyocyanin triggers tissue damage mainly by its redox cycling and induction of reactive oxygen species (ROS). The reactions between reduced glutathione (GSH) and pyocyanin were observed using absorption spectra from spectrophotometry and the reaction products analysed by nuclear magnetic resonance imaging. Pyocyanin reacted with GSH non-enzymatically at 37°C resulting in the production of red-brown products, spectophotometrically visible as a 480 nm maximum absorption peak after 24 h of incubation. The reaction was concentration-dependent on reduced glutathione but not on pyocyanin. Minimizing the accessibility of oxygen to the reaction decreased its rate. The anti-oxidant enzyme catalase circumvented the reaction. Proton-NMR analysis demonstrated the persistence of the original aromatic ring and the methyl-group of pyocyanin in the red-brown products. Anti-oxidant agents having thiol groups produced similar spectophotometrically visible peaks. The presence of a previously unidentified non-enzymatic GSH-dependent metabolic pathway for pyocyanin has thus been identified. The reaction between pyocyanin and GSH is concentration-, time-, and O2-dependent. The formation of H2O2 as an intermediate and the thiol group in GSH seem to be important in this reaction.