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Oxidative Effects (oxidative + effects)
Selected AbstractsOxidative effects in uninfected tissue in leaves of French bean (Phaseolus vulgaris) containing soft rots caused by Botrytis cinereaJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2003Ingo Muckenschnabel Abstract Several markers of oxidative processes have been measured in leaves of Phaseolus vulgaris infected with Botrytis cinerea, with the specific objective of investigating changes induced by this necrotrophic pathogen in tissue remote from the lesion. There was a progressive decrease with time in the contents of ascorbic acid (AA) in apparently healthy tissues from infected plants and non-inoculated plants grown under identical high-humidity conditions (abiotically stressed controls), and for periods >48 h this decrease was greater in the infected plants. This decline in AA content was accompanied by an elevation in the intensity of the electron paramagnetic resonance (EPR) signal from adducts of the spin trap ,-(4-pyridyl-1-oxide)- N - t -butylnitrone (POBN), a destabilisation of the (monodehydro) ascorbate radical (Asc·) signal in the presence of POBN, and an increase in the ratio of Asc· to AA in samples studied in the absence of the spin trap. These results are consistent with a shift in redox status to more oxidising conditions in apparently healthy tissue of infected plants and indicate the prevalence of chemical processes that are distinctly different from those in uninfected plants. However, no differences in lipid peroxidation products or the single-peak free radical and Fe(III) (g = 4.27) EPR signals were observed between these tissues distant from the lesions and those from abiotically stressed controls. In addition, the pathogen-derived sesquiterpene toxin botrydial and a second Mn(II) EPR signal, both of which are associated with Botrytis infection, were not detected in these ,apparently healthy' tissues. Copyright © 2003 Society of Chemical Industry [source] Attenuating effects of natural organic matter on microcystin toxicity in zebra fish (Danio rerio) embryos,benefits and costs of microcystin detoxicationENVIRONMENTAL TOXICOLOGY, Issue 1 2006Jimena Cazenave Abstract To contribute to the understanding of joined factors in the environment, impact of pure microcystins (-RR and -LF) on zebra fish (Danio rerio) embryos were investigated individually and in combination with a natural organic matter (NOM). The applied NOM was a reverse osmosis isolate from Lake Schwarzer See (i.e., Black Lake, BL-NOM). Teratogenic effects were evaluated through changes in embryonic development within 48 h of exposure. Detoxication activities were assessed by the activities of phase II biotransformation enzymes, soluble and microsomal glutathione S -transferase (s, mGST). Oxidative stress was assessed by determining both the production of hydrogen peroxide and by analyzing the activities of the antioxidative enzymes, guajacol peroxidase (POD), catalase (CAT), glutathione peroxidase (GPx), and the glutathione restoring enzyme glutathione reductase (GR). Energetic costs were evaluated by determining contents of fat, carbohydrates, and proteins in both exposed and control embryos. BL-NOM attenuated toxic effects of MC-LF and MC-RR verified by less pronounced teratological effects within 24 h, in particular, as well as less rise in the activity of s-GST, when compared with embryos exposed to either pure toxins or in combination with organic matter. BL-NOM also diminished oxidative effects caused by MC-LF; however, it failed to attenuate oxidative stress caused by MC-RR. Content of lipids was significantly reduced in exposed embryos following a trend similar to that obtained with teratological and enzymatic assays confirming the attenuating effect of BL-NOM. Physiological responses to microcystins and NOM required energetic costs, which were compensated to the expense of the energy resources of the yolk, which in turn might affect the normal development of embryos. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 22,32, 2006. [source] Microbiological Benefits of Removing Foam Formed After UV-Enhanced Ozonation of Poultry-Processing Chiller Water for RecyclingJOURNAL OF FOOD SCIENCE, Issue 3 2002M.E. Diaz ABSTRACT: Prior experiments using 250 mL samples of unscreened poultry overflow chiller water evaluated the beneficial bactericidal and oxidative effects of 4 different treatments (namely, O2/O3,O2/UV, O2/O3/UV, and O2 as the control) for improving microbiological safety, turbidity, and water-use efficiency allowing its reconditioning for reuse. When excluding foam as in this present study, synergistic reductions > 1.5 log CFU/mL for aerobic plate counts (APC) were additionally achieved after 4 min for all O3/UV treatment combinations as compared to serially applied treatments of O3 and UV acting separately. With foam present, 16-min O3/UV treatments were required to achieve similar results. We now report these additional benefits achieved by removing the foam formed by the advanced oxidation process of ultraviolet-photon enhanced ozonation. Furthermore, foam microbial and general physical content were analyzed to determine suitability as an additive in rendering-type processes. Treatment of the wastewater resulted in total plate counts between 2 to 4 Log CFU/mL in the foam after 8 min. Fat and protein constituted 89% of the solids collected (384 mg/L or 14% of the foam) with trace amounts of metal elements (for example, Ca, Na, K, Fe, Cu) present. Irradiating had negligible effect on foam characteristics yet decreased the amount of solids collected. [source] Photodynamic Action of Benzo[a]pyrene in K562 CellsPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2007Daza De Moraes Vaz Batista Filgueira Benzo[a]pyrene (BaP) is ubiquitously distributed in the environment, being considered the most phototoxic element among polycyclic aromatic hydrocarbon (PAHs). In presence of oxygen, PAHs can act as a photosensitizer by means of promoting photo-oxidation of biological molecules (photodynamic action, PDA). Thus, the present study analyzed the photodynamic action of BaP under UVA irradiation (BaP + UVA) and its oxidative effects on K562 cells. The evaluation of BaP kinetics showed that the highest intracellular concentration occurred after 18 h of incubation. Cell viability, reactive oxygen species (ROS) generation, lipid peroxidation, DNA damage (breaks and DNA,protein cross-link [DNAPC]) were assessed after exposure to BaP, UVA and BaP plus UVA irradiation (BaP + UVA). Cell viability was decreased just after exposure to BaP + UVA. Lipid peroxidation and DNA breaks increased after BaP + UVA exposure, while the DNAPC increased after BaP, UVA and BaP + UVA exposure, suggesting that BaP + UVA effects were a consequence of both type II (producing mainly singlet oxygen) and type I (producing others ROS) mechanisms of PDA. [source] | ||||||||||