Ethylenediurea (EDU) is the most common chemical used to prevent ozone (O3) injury on vegetation. Despite considerable research, its mode of action remains elusive and gene expression has not been studied. Transcripts of major antioxidant enzymes (catalase, glutathione reductase, glutathione peroxidase) were measured for the first time in a model plant (Phaseolus vulgaris cv S156) after short-term O3 exposure (0 or 90 ppb, 5 h/d, 4 days) and a single spray with EDU (0 or 300 ppm). Visible, physiological and biochemical parameters were assessed as indices of O3-induced stress. In O3-exposed EDU-protected plants, levels of transcript, enzyme activity, H2O2 accumulation, gas exchange and foliar visible injury were similar to those in control plants. These results suggest that EDU may halt the O3-induced ROS generation within 24 h from the exposure, and thus the downstream cascade mechanisms leading to increased H2O2 production, impaired gas exchange, and occurrence of leaf lesions.

The effect of different concentrations of NaCl, 0, 100, 200, 300 and 400mM, on the anatomical features and physiology of Myoporum bontioides was investigated. The photosynthetic rates (Pn) were significantly reduced by salt stress, with the lowest values at 400mM NaCl. The content of malondialdehyde (MDA), proline and soluble sugar, as well as the activities of peroxidase (POD) and catalase (CAT) increased at the beginning, but became similar to the control as the experiment proceeded. The NaCl effect on superoxide dismutase (SOD) was different from the other parameters, with a significant reduction at 400mM NaCl at Day 7. Salt glands were found in both upper and lower epidermis, and the ratios of the thickness of palisade to spongy mesophyll tissues increased with NaCl concentrations. The medullary ray was clearly damaged by NaCl at levels of 200 and 300mM. These results demonstrated that M. bontioides could adapt to a relatively low salinity, and was not a halophilous species.

The effects of BDE-47 on the growth and antioxidative responses of the seedlings of Kandelia obovata (Ko) and Avicennia marina (Am) were compared in an 8-week hydroponic culture spiked with different levels of BDE-47, 0.1, 1, 5 and 10mgl−1. The two highest BDE-47 levels significantly suppressed the growth and increased the activities of three antioxidative enzymes, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), of Ko in week 1. However, SOD and POD activities at high levels of BDE-47 became lower than the control in week 8. On the contrary, growth of Am was not affected at all contamination levels, and the activities of three enzymes were enhanced by BDE-47 in weeks 1 and 4, but such stimulatory effect became insignificant in week 8. Avicennia was more tolerant to BDE-47 toxicity than Kandelia, as its antioxidative enzymes could better counter-balance the oxidative stress caused by BDE-47.

By measuring a battery of cytological and biochemical biomarkers in adult female perch (Perca fluviatilis), the city of Stockholm (Sweden) was investigated as a point source of anthropogenic aquatic pollution. The investigation included both an upstream gradient, 46km westwards through Lake Mälaren, and a downstream gradient, 84km eastwards through the Stockholm archipelago. Indeed, there was a graded response for most of the biomarkers and for the muscle concentrations of ΣPBDE, four organotin compounds and PFOS in the perch. The results indicated severe pollution in central Stockholm, with poor health of the perch, characterised by increased frequency of micronucleated erythrocytes, altered liver apoptosis, increased liver catalase activity, decreased brain aromatase activity, and decreased liver lysosomal membrane stability. Some biomarker responses were lowest in the middle archipelago and increased again eastwards, indicating a second, partly overlapping, gradient of toxic effects from the Baltic Sea.

In order to assess the environmental quality of the Bizerte lagoon (Tunisia), biomarker and contaminant levels were measured in Mediterranean mussels (Mytilus galloprovincialis) from five selected sites. Persistent organic pollutants (POPs) were quantified in whole body and enzyme activities such as acetylcholinesterase (AChE), catalase (CAT) and glutathione S-transferase (GST) in gills. Despite the relatively low levels of organic contaminants, the selected biomarkers responded differently according to the pollution level at the different sites. GST and AChE activities were correlated with the amount of DDTs in mussel tissues. These two enzymatic activities were also correlated to temperature and pH. No significant difference was observed for CAT activity. Principal component analysis showed a clear separation of sampling sites in three different assemblages which is consistent with POP body burden in mussels. Our results confirmed the usefulness of combining biomarker and chemical analyses in mussels to assess chemical pollution in the Bizerte lagoon.

Perfluorinated chemicals (PFCs) are extremely persistent and have been found extensively in the environment and wildlife. Oceans are the final sink for many persistent organic pollutants (POPs) including PFCs. However, to date, there has been a lack of studies that investigated the environmental consequences of PFCs on marine organisms. To fill in this gap, environmental toxicity of two dominant PFCs, perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), was examined in a sentinel species, green mussel Perna viridis, using a series of biomarkers corresponding to different biological levels (molecular, cellular, and physiological). Correlations among these biomarkers were also investigated. The results showed that the tested compounds can induce a series adverse effect at different biological levels, including oxidative stress, DNA damage, membrane instability, suppressed filtration rate, and reduced body weight. Correlation analysis revealed that excess production of reactive oxygen species could be the major toxic pathway. An indirect mode of toxic action was also explored where adverse impacts could be secondary effects of PFC exposure. The joint analysis of biomarkers from multiple biological levels resulted in a comprehensive understanding of how PFC exposure can influence the health of organisms. The correlations of these biomarkers also provided a new perspective of the ecological consequences of PFCs.

The scope of this study was to investigate the uptake of chromium and nickel by onions (Allium cepa) and potatoes (Solanum tuberosum) and their impact on plant enzymes catalase (CAT, E.C. 1.11.1.6) and peroxidase (POX, E.C. 1.11.1.7). A greenhouse experiment was conducted, simulating the irrigating conditions existing in the two biggest tuber-producing regions of Greece (Asopos and Messapia). Plants were cultivated for 4 months in six irrigation lines, each one supplied by an aqueous solution, containing levels of Cr(VI) and Ni(II) ranging from 0 μg/L (control) to 1,000 μg/L. Significant statistical correlations were observed between (i) the levels of heavy metals in plants, (ii) the levels of heavy metals in plants and in irrigation water, and (iii) the levels of heavy metals and the enzymatic activities in plants. The existing EU legislation has no legal limits for Ni and Cr in food, and the nutritional implications of this study are discussed.

It now is widely recognised that the global temperature is rising, a phenomenon which could alter the effects of pollution on wildlife. In order to assess the role of temperature and exposure to chlorine due to cooling water discharges, a battery of metabolic, oxidative stress and histological parameters were evaluated in Mytilus galloprovincialis after 15 and 30 days at 15 °C and at two increased temperatures (+5 and +10 °C). Diverse gill pathologies such as haemolymphatic sinus dilatation, an increased number of mucocytes and granulocytes as well as a lower number of cilia were observed after 30 days exposure at higher temperatures. Protein, amino acid, triglyceride and fatty acid levels decreased when the temperature increased, as a consequence of higher energetic demand. Similarly, acetylcholinesterase, catalase and glutathione S-transferase activities showed an inhibition at higher temperatures, although gill lipid peroxidation levels remained unaffected. Our results suggest that increased temperatures induce deterioration in the health status of the mussels and in their defensive capacity against a polluted environment.

Cadmium is a toxic element for living organisms. This metal causes different damages to the cell, generating oxidative stress. In order to elucidate cadmium tolerance mechanism and increase tomato plant tolerance by inoculating a Cd-tolerant Burkholderia strain, we analyzed malondialdehyde, hydrogen peroxide content, and the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione S-transferase of two strains, one isolated from a soil contaminated with Cd (strain SCMS54) and the other from a soil without Cd (strain SNMS32). Strains SNMS32 and SCMS54 exhibited different SOD, CAT, and GR isoenzyme profiles in non-denaturing polyacrylamide gel electrophoresis analysis, with strain SCMS54 exhibiting an extra isoenzyme for all enzymes (Mn-SOD, CAT I, and GR IV, respectively). Despite accumulating more Cd, strain SCMS54 did not increase peroxide hydrogen and presented a fast antioxidant response (increasing SOD and CAT after 5 h of Cd exposure). In this way, strain SCMS54 exhibited a higher metabolic diversity and plasticity when compared to strain SNMS32, so it was selected for Cd–Burkholderia–tomato interaction studies. Inoculated tomato plants in the presence of Cd grew more than non-inoculated plants with Cd indicating that the SCMS54 increased tomato Cd tolerance. It appears that the strain isolated from Cd-contaminated soil (SCMS54) triggers a global stress response in tomato increasing plant tolerance, which may enable plants to be cultivated in Cd-contaminated soils.

Effects of perchlorate stress on the growth and physiological characteristics of rice (Oryza sativa L.) were studied in controlled water culture experiments. Perchlorate stress resulted in varied patterns of biomass allocation to O. sativa organs (roots, stems, and leaves). When stressed with higher perchlorate concentrations, the proportion of root biomass was higher, stem biomass was invariant, while leaf biomass was lower. Coefficients of variation in biomass of different organs followed the order leaf > stem > root, indicating that leaf growth has a higher sensitivity to perchlorate. Compared to the control, the chlorophyll and protein content of leaves and root vigor were lower, whereas malondialdehyde (MDA) content and catalase (CAT) activity were higher and related to perchlorate concentration and duration of stress. Superoxide dismutase (SOD) activity was initially high and then decreased markedly during the experiment, while peroxidase (POX) activity in perchlorate-treated rice was always higher than the POX activity of the control. POX was the most sensitive antioxidant enzyme to perchlorate stress. Correlation analysis showed a positive correlation between SOD activity and the fresh weight of the whole plant, and negative correlation with MDA content. The results suggest that perchlorate could induce oxidative stress and oxidative damage may be the main cause of physiological damage and growth inhibition in rice plants under perchlorate stress.