Wyniki wyszukiwania - BazTech

1

Influence of PEG-coated Bismuth Oxide Nanoparticles on ROS Generation by Electron Beam Radiotherapy

Sisin Noor Nabilah Talik, Anuar Muhammad Afiq, Dollah Norhayati, Razak Khairunisak Abdul, Algethami Merfat, Geso Moshi, Rahman Wan Nordiana

Polish Journal of Medical Physics and Engineering

|

2022

|

Vol. 28, Iss. 2

69--76

EN

Introduction: Nanoparticles (NPs) have been proven to enhance radiotherapy doses as radiosensitizers. The introduction of coating materials such as polyethylene glycol (PEG) to NPs could impact the NPs’ biocompatibility and their effectiveness as radiosensitizers. Optimization of surface coating is a crucial element to ensure the successful application of NPs as a radiosensitizer in radiotherapy. This study aims to investigate the influence of bismuth oxide NPs (BiONPs) coated with PEG on reactive oxygen species (ROS) generation on HeLa cervical cancer cell line. Material and methods: Different PEG concentrations (0.05, 0.10, 0.15 and 0.20 mM) were used in the synthesis of the NPs. The treated cells were irradiated with 6 and 12 MeV electron beams with a delivered dose of 3 Gy. The reactive oxygen species (ROS) generation was measured immediately after and 3 hours after irradiation. Results: The intracellular ROS generation was found to be slightly influenced by electron beam energy and independent of the PEG concentrations. Linear increments of ROS percentages over the 3 hours of incubation time were observed. Conclusions: Finally, the PEG coating might not substantially affect the ROS generated and thus emphasizing the functionalized BiONPs application as the radiosensitizer for electron beam therapy.

2

Inter-clutch egg differences and androgenesis in rainbow trout (Oncorhynchus mykiss, Walbaum 1792)

Polonis Marcin, Błaszczyk Agata, Jagiełło Krzysztof, Panasiak Ligia, Dobosz Stefan, Ocalewicz Konrad

Oceanological and Hydrobiological Studies

|

2021

|

Vol. 50, No. 2

160--168

EN

Ionizing radiation (IR) is applied to inactivate the nuclear genome in rainbow trout eggs during induced androgenetic development. However, IR-generated reactive oxygen species (ROS) may affect developmental potential of eggs and reduce the effectiveness of androgenesis. To verify this assumption, androgenetic development of rainbow trout was induced in eggs irradiated with 350 Gy of X-rays. Survival rates, pH of the ovarian fluid and activity of antioxidant enzymes, including SOD, CAT and GPx, were examined in non-irradiated and irradiated eggs originating from four females. Survival rates of androgenetic embryos developing in eggs produced by different females varied from 1% to 57% and these inter-clutch differences were significant. Eggs from female F4, which showed the highest developmental competence for androgenesis, also showed increased activities of SOD, CAT and GPx enzymes. The pH value of the ovarian fluid of each female was over 8 before and after irradiation, therefore it seems that radiation did not affect the ovarian fluid pH. Considering the above-mentioned inter-clutch differences, a strong maternal effect on the effectiveness of androgenesis can be assumed. Eggs with increased activity of antioxidant enzymes before irradiation should be expected to show increased developmental competence for androgenesis.

3

Activity of Antioxidant Enzymes under Induced Oxidative Stress

Deska Małgorzata

Journal of Ecological Engineering

|

2020

|

Vol. 21, nr 7

42--51

EN

Reactive oxygen species (ROS) include both oxygen free radicals and highly reactive oxygen compounds (such as ozone, singlet oxygen). They are formed in many metabolic processes, as well as under the influence of various environmental factors. Their impact on cells depends on their concentration and the duration of the process. Excessive level of ROS in a cell leads to oxidative stress. One of the defence mechanisms against ROS corresponds to antioxidant enzymes including SOD and CAT. This paper defines the changes in the activity of antioxidant enzymes caused by oxidative stress induced by nickel and paraquat in tissue of Acheta domesticus L, derived from various development lines. The obtained results defining the activity of SOD and CAT indicated the differences among individual tissues and the midgut showed the highest activity. Increased activity in relation to the control group results of CAT and SOD in the midgut and fat body of B-line individuals treated with pro-oxidant (particularly nickel) and inhibition of the CAT activity in the midgut of L-line crickets influenced by pro-oxidant indicate that the conducted screening changes the biochemical response to the stress factors. Moreover, the obtained results may indicate the relation of the activity of SOD and CAT with the lifespan of the tested insects.

4

Hyperbaric oxygen treatment is associated with lipid inflammatory response assessed uding serum platelet activating factor

Eren Esin, Yıldırım Furkan, Giray Ozlem, Yilmaz Necat

Polish Hyperbaric Research

|

2019

|

nr 2(67)

103--108

EN

Hyperbaric oxygen (HBO) treatment is generally a relatively safe therapy for various conditions. However, there are some adverse side effects. For example HBO tratment has been reported to increase the production of free oxygen radicals(FRs). Furthermore, to our knowledge, no previous clinical research has been carried out to study the involvement of platelet-activating factor(PAF)as the lipid oxidative stressor in patients undergoing HBO treatment. A total of 45 patients included in this study were first given clinical assessment and laboratory measurements before starting HBO treatment and were named group baseline. After the HBO treatment, the same clinical and laboratory measurements from the same patients were repeated and this was named group sesion >20.As expected, long-term HBO treatment had no effect on oxLDL (oxidized low-density lipoprotein), a lipid oxidative stress(OS) marker. However, the mean PAF values in the second group showed a statistically significant increase compared to their pretreatment values, (P <0. 002).As this is a preliminary study, there is a need for more detailed investigations that demonstrate the association of HBO treatment with the lipid inflammatory response. Therefore, there is need for further clinical study for OS markers such as oxLDL in HBO treatment. Clinical prospective studies are required to confirm our laboratory findings.

PL

Leczenie tlenem hiperbarycznym (HBO) jest na ogół stosunkowo bezpieczną terapią stosowaną w różnych schorzeniach. Niemniej jednak możliwe jest wystąpienie pewnych niekorzystnych skutków ubocznych. Przykładowo, istnieją doniesienia mówiące o tym, że leczenie przy użyciu HBO zwiększa produkcję wolnych rodników tlenowych (free radicals, FR). Ponadto, zgodnie z naszą wiedzą, nie prowadzono wcześniejszych badań klinicznych w celu zbadania udziału czynnika aktywującego płytkki krwi (PAF) jako lipidowego stresora oksydacyjnego u pacjentów poddawanych leczeniu HBO. Łącznie 45 pacjentów objętych badaniem zostało poddanych ocenie klinicznej i pomiarom laboratoryjnym przed rozpoczęciem leczenia HBO, którym nadano nazwę grupy wyjściowej. Po leczeniu HBO powtórzono te same pomiary kliniczne i laboratoryjne u tych samych pacjentów i oznaczono je jako sesję grupową >20. Zgodnie z oczekiwaniami, długotrwałe leczenie HBO nie miało wpływu na marker oxLDL (utlenione lipoproteiny o małej gęstości), czy marker lipidowego stresu oksydacyjnego (OS). Jednakże, średnie wartości PAF w drugiej grupie wykazały statystycznie istotny wzrost w porównaniu z ich wartościami w leczeniu wstępnym (P <0,002). Istnieje zatem potrzeba dalszych badań klinicznych nad markerami OS, takimi jak oxLDL, w leczeniu HBO. Kliniczne badania prospektywne są konieczne w celu potwierdzenia wyników badań laboratoryjnych.

5

Białka błony zewnętrznej fusobacterium nucleatum jako potencjalny czynnik promocji nowotworu jelita grubego

Lesiów M. K., Krupa K., Komarnicka U. K., Walencik P. K.

Wiadomości Chemiczne

|

2018

|

[Z] 72, 7-8

585--596

EN

Fusobacterium nucleatum is a Gram-negative, anaerobic bacterium located in an oral cavity. This bacterium can migrate with blood to the different part of the human body e.g colon. The studies suggest participation of Fn in a colorectal cancer promotion, but a particular mechanism of this disease is still unclear. Colorectal cancer leads to million of new death cases each year. It is third in the worldwide in terms of mortality. The predictions for the coming years are not optimistic. The statistics encourage researchers to know the details of the mechanism of colorectal cancer. It is suggest, that outer membrane proteins of Fn are responsible for development of this disease. Transition metal ions such as Cu(I), Cu(II), Fe(II) can coordinate to proteins and generate free radicals by Fenton reaction. Reactive oxygen species (ROS) destroy important biological macromolecules such as DNA, proteins or lipids and cause different diseases. The paper presents characteristics of Fn and its outer membrane proteins, description of copper(II) complexes and their ability to ROS generation.

6

Reconstruction of Wetland Zones: Physiological and Biochemical Responses of Salix variegata to Winter Submergence — A Case Study from Water Level Fluctuation Zone of the Three Gorges Reservoir

Miao L., Xiao F., Xu W., Yang F.

Polish Journal of Ecology

|

2016

|

Vol. 64, nr 1

45--52

EN

The Salix variegata Franch. seedlings planted in the Three Gorges Reservoir (TGR) water level fluctuation zone (WLFZ) could survive after experiencing several seasons of winter submergence. We investigated the recovery mechanisms of S. variegata seedlings planted at the elevation of 168 m and 172 m in the TGR WLFZ after winter submergence. The results indicated that winter submergence caused some impacts on S. variegata seedlings with increases of hydrogen peroxide (H2O2), superoxide anions radical (O2-.), and malondialdehyde (MDA) levels, and decreases of antioxidant enzymatic systems during recovery stage after winter submergence. However, further analyses of relative water content (RWC), pigment content, proline content, carbohydrate content and several other antioxidant enzymatic activities (catalase (CAT), guaiacol peroxidase (G-POD), and glutathione peroxidase (GSH-POD)) showed that S. variegata seedlings were well recovered after winter submergence. These results indicate that S. variegata possesses strong winter submergence tolerance and adaptation to the specific hydrological environment in the TGR WLFZ. Therefore, S. variegata should be popularized as native tree species during the revegetation in the TGR WLFZ.

7

Effects of silver nanoparticles of different sizes on cytotoxicity and oxygen metabolism disorders in both reproductive and respiratory system cells

Zapór L.

Archives of Environmental Protection

|

2016

|

Vol. 42, no. 4

32--47

EN

Silver nanoparticles (AgNPs) are widely used in numerous industries and areas of daily life, mainly as antimicrobial agents. The particles size is very important, but still not suffi ciently recognized parameter infl uencing the toxicity of nanosilver. The aim of this study was to investigate the cytotoxic effects of AgNPs with different particle size (~ 10, 40 and 100 nm). The study was conducted on both reproductive and pulmonary cells (CHO-9, 15P-1 and RAW264.7). We tested the effects of AgNPs on cell viability, cell membrane integrity, mitochondrial metabolic activity, lipid peroxidation, total oxidative and antioxidative status of cells and oxidative DNA damage. All kinds of AgNPs showed strong cytotoxic activity at low concentrations (2÷13 μg/ml), and caused an overproduction of reactive oxygen species (ROS) at concentrations lower than cytotoxic ones. The ROS being formed in the cells induced oxidative damage of DNA in alkaline comet assay. The most toxic was AgNPs<10 nm. The results indicate that the silver nanoparticles, especially less than 10 nm, may be harmful to the organisms. Therefore, risk should be considered when using nanosilver preparations and provide appropriate protective measures when they are applied.

PL

Nanocząstki srebra (AgNPs), ze względu na silne właściwości bakteriobójcze, mają szerokie zastosowanie w wielu dziedzinach przemysłu, biomedycynie i produktach konsumenckich. Rozmiar cząstek jest istotnym, ale wciąż niewystarczająco zbadanym parametrem wpływającym na toksyczność nanosrebra. W pracy oceniono toksyczne działanie różnej wielkości cząstek srebra (~ 10, 40 i 100 nm) na komórki układu rozrodczego i oddechowego (CHO-9, 15P-1 i RAW264.7). Badano wpływ AgNPs na przeżywalność komórek, przepuszczalność błon komórkowych i aktywność metaboliczną komórek, zaburzenia metabolizmu tlenowego oraz odległe skutki działania w postaci uszkodzeń materiału genetycznego (DNA). Wszystkie badane AgNPs wykazywały silne działanie cytotoksyczne, w zakresie niskich stężeń (2÷13 μg/ml) oraz powodowały powstawanie stresu oksydacyjnego w komórkach w stężeniach niższych niż cytotoksyczne. Powstające w komórkach reaktywne formy tlenu powodowały oksydacyjne uszkodzenia DNA wykrywane w teście kometowym. Najsilniejsze działanie wykazywały cząstki o wielkości < 10 nm. Otrzymane wyniki wskazują, że nanocząstki srebra, zwłaszcza poniżej 10 nm, mogą stanowić zagrożenie dla organizmów. Dlatego też należy rozważyć ryzyko stosowania preparatów z nanosrebrem i zapewnić środki zapobiegające ich niekontrolowanemu uwalnianiu.

8

Zmiana aktywności enzymatycznej antyoksydantów biomarkerem stresu oksydacyjnego u organizmów żywych

Zakrzewski D., Zawisza-Raszka A.

Laboratorium - Przegląd Ogólnopolski

|

2014

|

nr 5-6

65--67

PL

Stres oksydacyjny u organizmów oddychających tlenowo związany jest z nadprodukcją w ich komórkach reaktywnych form tlenu (RFT), co może mieć szkodliwe i destabilizujące działanie w stosunku do struktur komórkowych, białek czy DNA. Obroną przeciw RFT są antyoksydanty, w tym enzymy takie jak: S-transferaza glutationowa, katalaza czy dysmutaza ponadtlenkowa, których zmiany aktywności mogą być biomarkerami stresu oksydacyjnego.

EN

For aerobic organisms the oxidative stress is a producing of high level reactive oxygen species (ROS) in cells. It is dangerous and harmful for cellular structures, proteins or DNA because it may to cause a destabilization of the structures. Defense against ROS are enzymatic antioxidants such as glutathione S-transferase, catalase or superoxide dismutase, which the changes of activity may be the biomarkers of oxidative stress.

9

Wpływ środowiska na barierę antyoksydacyjną człowieka

Bombolewska K., Dróżdż J., Koim-Puchowska B.

Journal of Ecology and Health

|

2013

|

R. 17, nr 4

175--178

PL

Tlen jest życiodajną substancją dla organizmów tlenowych na ziemi. Może powodować także uszkodzenia składników komórkowych, prowadząc do zaburzenia procesów fizjologicznych organizmu, rozwoju wielu schorzeń, a w konsekwencji nawet śmierci. Reaktywne formy tlenu (RFT) powstają zarówno w trakcie procesów zachodzących wewnątrz komórek, jak i pod wpływem działania zewnętrznych czynników środowiskowych, m.in.: zanieczyszczenie środowiska, dym tytoniowy, dieta, styl życia oraz metale ciężkie. Organizmy tlenowe wykształciły mechanizmy obronne przed działaniem szkodliwym RFT są to mechanizmy obrony antyoksydacyjnej: mechanizmy enzymatyczne (SOD, CAT), białka (ferrytyna, ceruloplazmina i haptoglobina.) oraz antyoksydanty niskocząsteczkowe: glutation, witamina E, witamina C, bilirubina, kwas moczowy. Zaburzenia równowagi pomiędzy powstawaniem reaktywnych form tlenu RFT a działaniem systemów obronnych organizmu, powodują stres oksydacyjny, który jest przyczyną poważnych zaburzeń metabolizmu komórkowego. Wzmożona produkcja RFT powoduje niszczenie białek, błon komórkowych i DNA. Uszkodzenia DNA prowadzą do mutacji, a te leżą u podłoża procesów nowotworowych.

EN

Oxygen is the life-giving substance for aerobic organisms on earth. On the other hand, it can damage cellular components, leading to abnormal physiological processes in the body, the development of many diseases, and consequently death. Reactive oxygen species (ROS) are formed both in the course of processes inside the cells, as well as under the influence of external environmental factors such as environmental pollution, tobacco smoke, diet, lifestyle and heavy metals. Aerobic organisms have evolved defenses against harmful ROS, and their antioxidant defense mechanisms are: enzymatic mechanisms (SOD, CAT), proteins (ferritin, ceruloplasmin, and haptoglobin.) and the low molecular weight antioxidants: glutathione, vitamin E, vitamin C, bilirubin, and uric acid. An imbalance between the generation of reactive oxygen species and the effects of ROS defense systems of the body causes oxidative stress, which is the cause serious disturbances in cellular metabolism. Increased production of ROS causes the destruction of proteins, cell membranes and DNA. DNA damage leads to mutations and those processes underlie cancer.

10

Quantifying Transient Psychological Stress Using a Novel Technique: Changes to PMA-Induced Leukocyte Production of ROS In Vitro

Shelton-Rayner G. K., Mian R., Chandler S., Robertson D., Macdonald D. W.

International Journal of Occupational Safety and Ergonomics

|

2011

|

Vol. 17, No. 1

3--13

EN

Although much work has been conducted to quantify the long-term physiological effects of psychological stress, measures of short-term, low-level stress have been more elusive. This study assessed the effect of exposure of volunteers to a mild, brief, psychologically stressful event, on the functional ability of leukocytes in whole blood to respond to phorbol 12-myristate 13-acetate (PMA) in vitro. Volunteers operated a car electric window and adjusted it to 4 pre-determined positions. Between each operation the mechanism’s polarity was covertly altered (group B) or remained unaltered (group A). For each treatment group 10 different subjects provided capillary blood samples pre- and post-stressor. Using a chemiluminescent technique termed leukocyte coping capacity, the ability of leukocytes to produce reactive oxygen species (ROS) in vitro was assessed. ROS release differed significantly at 10 min post-stressor between treatment groups, suggesting exposure to acute psychological stress leads to a reduced ability to respond to bacterial challenge.

11

An image segmentation method to reveal regions of stress manifestation in stained cucurbits' leaves using LVQ neural network

Gocławski J., Sekulska-Nalewajko J.

Automatyka / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

|

2011

|

T. 15, z. 3

105-118

EN

In the paper an image segmentation method has been presented, which enables to detect cucurbits' leaves stress manifestation featured by the accumulation of reactive oxygen species (ROS) like hydrogen peroxide (H2O2) or superoxide anion radical (O2 ). After specific leaf staining the regions can be distinguished in colour space from the intact leaf parts. The proposed algorithm, developed in MATLAB environment, includes the segmentation of scanned leaf images with selected background, the exclusion of certain leaf parts and the classification of reminded leaf blade image pixels in H, S (hue, saturation) colour space. The classification is based on LVQ type neural network with several neurons in an internal layer and two neurons in an output layer, which represent image pixels of stained and unstained tissue respectively. The network learning process uses representative leaf image pixel data and binary template images of stress manifestation regions prepared manually by specialists. The classifier was 5-fold cross validated with the pixel H, S data of learned image and validated with the data of other images (with templates). The computed classification errors have been included. The experiments of stress regions detection carried out for the series of 12 images gave a few percent errors compared to manual classification.

PL

W artykule przedstawiono metodę segmentacji obrazów, która pozwala wykrywać obszary ujawniania się stresu na liściach roślin dyniowatych charakteryzujących się akumulacją reaktywnych form tlenu (ROS), takich jak woda utleniona (H2O2) lub anionorodnik ponadtlenkowy (O2). W następstwie specyficznego wybarwiania obszary te dają się odróżnić od nietkniętych części liścia w przestrzeni koloru. Proponowany algorytm, opracowany w środowisku MATLAB, obejmuje segmentację obrazów liści zeskanowanych na wybranym tle, wyłączanie pewnych partii liścia z dalszej analizy i klasyfikację pozostałych pikseli obrazu blaszki liścia w przestrzeni H, S (odcień, nasycenie). Klasyfikacja bazuje na sieci neuronowej typu LVQ z kilkoma neuronami w warstwie wewnętrznej i dwoma neuronami warstwy wyjściowej, reprezentującymi piksele obrazu odpowiadające wybarwionej i niewybarwionej tkance liścia. Proces uczenia się sieci wykorzystuje dane pikseli reprezentatywnych obrazów i binarne wzorce klasyfikacji obszarów ujawniania stresu przygotowane manualnie przez specjalistów. Klasyfikator poddano 5-krotnej ocenie krzyżowej dla danych H, S obrazu podlegającego uczeniu się i oceniono dla danych z innych obrazów (mających wzorce). Dołączono obliczone błędy klasyfikacji. Eksperymenty wykrywania obszarów stresu przeprowadzone dla serii 12 obrazów dały kilkuprocentowe błędy w porównaniu z klasyfikacją manualną.

12

5',8-cyklo-2'-deoksyadenozyna. Podwójne uszkodzenie w obrębie pojedynczego nukleozydu/nukleotydu

Karwowski B.T.

Wiadomości Chemiczne

|

2010

|

[Z] 64, 11-12

1013-1052

EN

Free radicals can react with different biomolecules present in the cells such as lipids, sugars or nucleic acid peptides. These free radicals initiate reactions with DNA or RNA molecules and then can lead to changes in the genome sequence. These mutations are most probably responsible for a number of different diseases (involving a change in the genome sequence) or, at least, can accompany them. Reactive oxygen species and more specifically - hydroxyl radical can react with DNA molecules and lead to changes in their structures. Formation of radicals at C5' and C8 atoms of 2'-deoxyadenosine leads, through intramolecular cyclisation, to 5',8-cyclo-2'-deoxyadenosine (cdA) derivatives. Frequency of DNA damage occurrence surges with an increase of an ionizing radiation dose. Different repair systems are however present in cellular machinery: BER, which exploits glycosylase and NER - a more complex process involving the removal of damaged oligonucleotides. The later is the basic mechanism for removal the 5',6-cyclo-2'-deoxynucleosides and 5',8-cyclo-2'-deoxynucleosides like cdA. Their defective activity may be responsible for many types of diseases, such as Parkinson, Alzheimer, chronic hepatitis, HCV, atopic dermatitis and different types of cancer. The mechanistic, structural and biochemical studies presented in this work produce quite clear answer as to the approximate range level of the (5'R)-cdA and (5'S)-cdA accumulation in the genome after the lesion period. Using quantum chemistry methods (DFT) paths of the cyclisation reaction have been determined. From the structural analysis point of view, it has been demonstrated that the covalent bond between C(5') and C(8) in nucleoside induces an unusual West conformation of the furanose ring. Based on the NMR data analysis it can be postulated that the rigid and fixed structure of cdA can strongly influence the global geometry of oligonucleosides. Moreover, using the quantum mechanic study of double strand DNA it has been demonstrated that the presence of (5'S)-cdA provokes a "domino effect" extending towards the 5'-end of the strand with this lesion. No domino effect is observed for the 3'-end. The obtained biological results indicate that the presence of (5'S)-cdA in the complementary strand to the strand under repair on the 5'-end side is the critical factor for the inhibition of the BER process of DNA.

13

Effect of non-modified and modified nanodiamond particles by Fenton reaction on human endothelial cells

Solarska K., Gajewska A., Skolimowski J., Woś R., Bartosz G., Mitura K.

Journal of Achievements in Materials and Manufacturing Engineering

|

2010

|

Vol. 43, nr 2

603--607

EN

Purpose: The use of carbon nanoparticles in medicine is increasing due to their high biocompatibility. Nanopowders are one of the best materials which can be used in medicine on medical implants and surgical tools. DPP (Diamond Powder Particles) obtained by different methods which can be expected to affect their properties, including biocompatibility, were compared. The aim of the present study was to compare the biocompatibility of Diamond Powder Particles (DPP) obtained by detonation method and graphite on the basis of their interactions with human endothelial cells. Design/methodology/approach: The effect of nanodiamonds on cell proliferation HUVEC-ST and production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) was studied. We used FT-IR Spectroscopy attributive chemical function groups. Findings: In this subject the material characterization of nanodiamond powders and influence on endothelial cells. Practical implications: Biological research with endothelial cells and nanodiamond powder are the introduction to application in human’s treatment. Originality/value: Nanodiamond powders with chemical modified surface.

14

Molecular Perspective Review of Biochemical Role of Nucleobases Modified by Oxidative Stress

Cysewski P.

Computational Methods in Science and Technology

|

2010

|

Vol. 16, No. 1

51-72

EN

Numerous damages to cellular DNA are imposed by oxidative stress. Formation of stable products resulting from oxidation of nucleobases is one of many observed consequences. The oxidized species constitute a class of heterocyclic compounds with great diversities of physicochemical properties. Modified nucleosides significantly differ from their canonical protoplasts by tautomeric equilibriums, protolytic properties in the gas phase and water solution, they have altered oxidative susceptibility and N-glycosidic bond stabilities. However, what is most important, they have overwhelmingly altered pairing properties, which are directly responsible for observed cytotoxic properties of these lesions. Besides, since many analogues are structurally different with respect to canonical bases their presence in DNA must impose many energetic, structural and dynamic modifications. These aspect are reviewed as fruits of project no 39 supported by computational grant in Poznań Supercomputing and Networking Center (PSNC, Poland).

15

Photosynthetic and physiological responses of Swida hemsleyi (C.K. Schneid. et Wangerin) Sojak (Cornaceae) subjected to enhanced UV-B radiation and to nitrogen supply

Yao X., Liu Q.

Polish Journal of Ecology

|

2009

|

Vol. 57, nr 3

483-494

EN

Atmospheric ozone remains depleted which in turn leads to the increase of UV-B radiation reaching the surface of the earth and in the same time more and more nitrogen will be imported into the terrestrial ecosystems through nitrogen deposition. These two factors will operate simultaneously. The photosynthetic and physiological responses of deciduous broad leaved species Swida hemsleyi occurring commonly at 1350-3700 m a.s.l. subjected to enhanced UV-B and to nitrogen supply were studied. The experimental design included two levels of UV-B treatments (ambient UV-B, 11.02 KJ m[^-2] day[^-1] and enhanced UV-B, 14.33 KJ m[^-2] day[^-1] and two nitrogen levels (without supplemental nitrogen supply and with supplemental nitrogen supply). An experiment was conducted in open semi-field condition in Maoxian Ecological Station of Chinese Academy of Sciences, Sichuan province, China at 1820 m a.s.l. Enhanced UV-B caused a marked decline in growth parameters, net photosynthetic rate, stomatal conductance to water vapour, chlorophyll pigments, whereas it induced an increase in rate of reactive oxygen species (ROS) production and ROS accumulation and malondialdehyde (MDA) content. Enhanced UV-B also induced an increase in leaf thickness and antioxidant compounds content, such as carotenoids and proline content. On the other hand, nitrogen supply caused an increase in some growth parameters, chlorophyll pigments and antioxidant compounds, and reduced ROS accumulation. However, nitrogen supply did not affect MDA content under enhanced UV-B, though it increased antioxidant compounds content and reduced the rate of ROS production and ROS accumulation. These results implied that enhanced UV-B brought harmful effects on Swida hemsleyi seedlings and supplemental nitrogen supply could alleviate the adverse effects of UV-B radiation on plants to some extent.

16

Rola reaktywnych form tlenu w powstawaniu chorób

Jaźwińska-Kuliś J.

Laboratorium - Przegląd Ogólnopolski

|

2007

|

nr 4

47

PL

W systemach biologicznych najbardziej znaczącym akceptorem elektronów jest tlen cząsteczkowy, który z łatwością przyjmuje niesparowane elektrony, dając grupę częściowo zredukowanych cząstek powszechnie znanych jako reaktywne formy tlenu (RFT). Należą do nich anionorodnik ponadtlenkowy (O2 ·), nadtlenek wodoru (H202) oraz najbardziej reaktywny rodnik hydroksylowy (OH·). Formy te indukują rozwój całego szeregu reaktywnych cząstek zwanych wolnymi rodnikami. Są one stale produkowane w żywym organizmie jako część normalnego metabolizmu komórek oraz w odpowiedzi na działanie wielu szkodliwych czynników. RFT mogą inicjować łańcuch reakcji wolnorodnikowych groźnych dla wieku struktur komórkowych.

EN

The most important electron acceptor in biological systems is molecular oxygen, which readily accepts unpaired electrons to give rise to a family of partially reduced species commonly known as a reactive oxygen species (ROS). The oxygen derived radicals include species such as superoxide (O2 ·), hydrogen peroxide (H202) and the most reactive hydroxyl radical (OH·). These forms induce the development of the whole range of reactive species labeled free radicals. Free radical are constantly produced in the body as a part of normal cell metabolism, and in response to exposure to many of damaging agents. ROS may be involved in the initiation of free radicals chain reactions, which are highly damaging to cell components.

17

Metody oznaczania oraz identyfikacji związków przeciwutleniających

Tarko T., Duda-Chodak A.

Laboratorium - Przegląd Ogólnopolski

|

2007

|

nr 3

32--37

PL

Przeciwutleniacz to substancja, która obecna w niskim stężeniu, opóźnia bądź eliminuje reakcje utleniania. Zewzględu na duże zróżnicowanie w budowie i funkcji tych związków istnieje wiele metod ich oznaczania i identyfikacji. Większość badań opiera się na ocenie aktywności antyoksydacyjnej, będącej sumą właściwości poszczególnych składników zawartych w badanym materiale. Najczęściej wykorzystuje się metody spektrofometryczne i kolorometryczne, ale także elektrochemiczne. Do identyfikacji związków o charakterze przeciwutleniającym służą techniki chromatograficzne, głównie HPLC.

EN

Antioxidant is a substance that in low concentration delays or inhibits oxidation. There are many methods of antioxidants determination and identyfication due to the diversification of their structure and function. Majority of investigations are based on evaluation of antioxidant activity, which equals the sum of the particular components properties in a sample. Spectrophotometric and colorometric methods are used most often, as well as electrochemical ones. The chromatograohis techniques , mainly HPLC, are used for identification of antioxidants.

18

Nanokrystaliczny diament (NCD) - nowy i obiecujący materiał do zastosowań medycznych

Walkowiak B., Okrój W., Przybyszewska I., Pirek M., Szymański W., Kosęda P., Jakubowski W.

Inżynieria Biomateriałów

|

2004

|

R. 7, nr 35-36

62-67

PL

Nanokrystaliczny diament (NCD) przejawia szereg interesujących właściwości. Niektóre z nich mogą być atrakcyjne w zastosowaniach biomedycznych. Niniejsze opracowanie dotyczy badań nad anty-oksydacyjnymi właściwościami NCD, jego tombozgodnością oraz odpornością na powstawanie biofilmu. Badania zrealizowano stosując następujące metody: 1. Obserwacja luminolo-zależnej luminescencji, wywoływanej przez reaktywną formę tlenu (kwas podchlorawy) generowaną przez chloraminę T w osoczu krwi, w obecności proszków diamentowych. Intensywność mierzonej luminescencji jest wprost proporcjonalna do ilości reaktywnych form tlenu w badanym układzie. Stwierdzono, że obecność proszków diamentowych znamiennie i w sposób zależny od ich koncentracji wpływa na obniżenie ilości kwasu podchlorawego. 2. Obserwacja adhezji płytek krwi do badanych powierzchni z użyciem skaningowego mikroskopu elektronowego. Wykazano, że płytki krwi tylko w niewielkiej ilości, w porównaniu z powierzchnią stali medycznej, przylegały do powierzchni NCD. Jednak skazy powierzchni NCD były miejscem intensywnej adhezji płytek krwi. 3. Obserwacja zasiedlania badanych powierzchni przez komórki E.coli, z zastosowaniem mikroskopu fluorescencyjnego. Pokazano, że bakterie najchętniej kolonizowały powierzchnię stali medycznej 316L. Znacznie słabiej powierzchnię stopu tytanu Ti6Al4V. Najbardziej oporna na kolonizację komórkami E.coli była powierzchnia NCD. Uzyskane wyniki wskazują również na wzrost podatności na kolonizację przez mikroby powierzchni opłaszczonej białkami.

EN

Nanocrystalline diamond (NCD) exhibits several interesting properties. Some of them can be attractive in biomedical applications. This study concerns of research on anti-oxidative properties of NCD, its thrombocompatibility, as well as its resistance to bacterial biofilm formation. Results were obtained using following methods: 1. Observation of luminal-depend luminescence caused by reactive oxygen species (hypochlorous acid) generated by chloramines T in blood plasma, in the presence of diamond powders. The intensity of measured luminescence is directly proportional to the amount of reactive oxygen species in the system. We have found, that presence of diamond powder particles (DPP) significantly and concentration-dependently causes decrease in hypochlorous acid amount. 2. Observation of platelets adhesion to examined surface with use of scanning electron microscopy (SEM). It was proved, that blood platelets adhered to NCD surface only in a very small amount when compared to medical steel surface. However, defects of the NCD surface were the place of intensive platelet adhesion. 3. Observation of colonization of examined surfaces by E.coli cells, was performed with use of fluorescence microscope. It was shown that bacteria colonized predominantly medical steel 316L surface whereas titanium alloy Ti6Al4V surface was colonized considerably less. NCD surface was the most resistant to E.coli cells colonization. The received results also point higher susceptibility to microbial colonization of surface coated by proteins.

19

The bystander effect: is reactive oxygen species the driver?

Szumiel I.

Nukleonika

|

2003

|

Vol. 48, nr 3

113-120

EN

The paper reviews selected examples of the bystander effect, such as clonogenic survival decrease, chromosomal aberrations and mutations. The similarities and differences between the biological effects in directly targeted and bystander cells are briefly discussed. Also reviewed are the experimental data which support the role of reactive oxygen species (ROS), especially *O2-, as mediators of the bystander effect. Endogenously generated ROS, due to activation of NAD(P)H oxidases, play a key role in the induction of DNA damage in bystander cells. All the observed effects in bystander cells, such as alterations in gene expression patterns, chromosomal aberrations, sister chromatid exchanges, mutations, genome instability, and neoplastic transformation are the consequence of DNA damage.