Exposure to contaminants exacerbates oxidative stress in amphipod Monoporeia affinis subjected to fluctuating hypoxia

Gorokhova, E.; Lof, M.; Reutgard, M.; Lindstrom, M.; Sundelin, B.
2013 | Aquat. Toxicol. | 127 (46-53)

Fitness and survival of an organism depend on its ability to mount a successful stress response when challenged by exposure to damaging agents. We hypothesized that co-exposure to contaminants may exacerbate oxidative stress in hypoxia-challenged benthic animals compromising their ability to recover upon reoxygenation. This was tested using the amphipod Monoporeia affinis exposed to hypoxia followed by reoxygenation in sediments collected in polluted and pristine areas. In both sediment types, oxygen radical absorbance capacity (ORAC) and antioxidant enzyme activities [superoxide dismutase (SOD) and catalase (CAT)] increased during hypoxia, suggesting that M. affinis has a strategy of preparation for oxidative stress that facilitates recovery after a hypoxic episode. Exposure to contaminants altered this anticipatory response as indicated by higher baselines of ORAC and SOD during hypoxia and no response upon reoxygenation. This coincided with significantly elevated oxidative damage evidenced by a marked reduction in glutathione redox status (ratio of reduced GSH/oxidized GSSG) and an increase in lipid peroxidation (TSARS levels). Moreover, RNA:DNA ratio, a proxy for protein synthetic activity, decreased in concert with increased TBARS, indicating a linkage between oxidative damage and fitness. Finally, inhibited acetylcholinesterase (AChE) activity in animals exposed to contaminated sediments suggested a neurotoxic impact, whereas significant correlations between AChE and oxidative biomarkers may indicate connections with redox state regulation. The oxidative responses in pristine sediments suggested a typical scenario of ROS production and removal, with no apparent oxidative damage. By contrast, co-exposure to contaminants caused greater increase in antioxidants, lipid peroxidation, and slowed recovery from hypoxia as indicated by CAT, GSH/GSSG, TBARS and AChE responses. These results support the hypothesized potential of xenobiotics to hamper ability of animals to cope with fluctuating hypoxia. They also emphasize the importance of understanding interactions between antioxidant responses to different stressors and physiological mechanisms of oxidative damage. (c) 2012 Elsevier B.V. All rights reserved.

Perfluorooctane sulfonate accumulation and parasite infestation in a field population of the amphipod

Jacobson, T.; Holmström, K.; Yang, G.; Ford, A.T.; Berger, U.; Sundelin, B.
2010 | Aquat. Toxicol. | 98 (99-106)

Single and combined effects of hypoxia and contaminated sediments on the amphipod Monoporeia affinis in laboratory toxicity bioassays based on multiple biomarkers

Gorokhova, E; Löf, M; Halldorsson, HP; Tjärnlund, U; Lindström, M; Elfwing, T; Sundelin, B
2010 | Aquat. Toxicol. | 99 (2) (263-274)
acetylcholinesterase activity , ache , antioxidant enzyme-activities , antioxidant enzymes , baltic sea , comet assay , contaminated sediments , dna strand breaks , hypoxia , lipid-peroxidation , long-term changes , multivariate analysis , mytilus edulis , oxidative stress , oxidative stress biomarkers , oxygen depletion , pontoporeia-femorata

In estuaries, hypoxic conditions and pollution are among the major factors responsible for the declines in habitat quality, yet little is known about their combined effects on estuarine organisms. In this study, to investigate single and combined effects of hypoxia and contaminated sediment, the Baltic amphipod Monoporeia affinis was exposed for 5-9 days to four different combinations of oxygen conditions (moderate hypoxia vs. normoxia) and contamination (polluted vs. unpolluted sediments) at environmentally realistic levels. To detect oxidative stress, a suite of biomarkers was used - antioxidant enzymes [superoxide dismutases (SOD), catalase (CAT), and glutathione S-transferases (GST)], acetylcholinesterase (AChE), lipid peroxidation status (TBARS concentration), protein carbonyl content (PCC), and DNA strand breakage (DNA-SB). To assay effects at the organism level, we used RNA:DNA ratio as a proxy for growth and metabolic rate and mortality. There were significant increases in CAT and SOD activities and TBARS levels in response to both moderate hypoxia and contaminated sediment, while GST increased and AChE decreased in response to the contamination only. Significant positive correlations were observed among the antioxidant enzymes and between the enzyme activities and TBARS concentration, suggesting a complex response to the oxidative stress. No significant changes in PCC were recorded in any of the treatments. Furthermore, the negative effect of hypoxia on DNA integrity was significant; with frequency of DNA-SB increasing in animals exposed to hypoxia in contaminated sediment. Despite clear effect at the cellular and biochemical levels, no responses at the organism level were observed. Multivariate analyses of the dataset have allowed us to link exposure factors to individual biomarker responses. Of the potential biomarkers assessed in this study, CAT activity was found to be associated with hypoxia, while SOD, GST and AChE activities appear to predict best the effects of exposure to sediments containing several contaminants (e.g. heavy metals, PCBs and PAHs), and TBARS concentration is particularly indicative of combined effects of hypoxia and contamination. In addition to providing new knowledge on the combined effects of multiple stressors on estuarine organisms, the findings of the present study are also important to understand data from biomonitoring studies in the Baltic Sea and in other regions where multiple stress factors co-occur. (C) 2010 Elsevier B.V. All rights reserved.

Combined effects of temperature and a pesticide on the Baltic amphipod Monoporeia affinis

Jacobson, T.; Prevodnik, A.; Sundelin, B.
2008 | Aquat Biol | 1 (269-276)

Reproduction disorders in the benthic amphipod Monoporeia affinis: an effect of low food resources

2008 | Aquat Biol | 2 (179-190)

Uptake of diatoms in Baltic Sea macrozoobenthos during short-term exposure to severe and moderate hypoxia

Ejdung, G.; Byrén, L.; Eriksson Wiklund, A.-K.; Sundelin, B.
2008 | Aquat Biol | 3 (89-99)

Biological effects of contaminants: The use of embryo aberrations in amphipod crustaceans for measuring effects of environmental stressors

2008 | 41 (1-23) | ISBN: 978-87-7482-013-0

Population decline of amphipod Monoporeia affinis in Northern Europe: consequence of food shortage and competition?

2008 | J. Exp. Mar. Biol. Ecol. | 367 (81-90)

Genetic diversity in the Baltic Sea amphipod Monoporeia affinis

Löf, M.; Gardeström, J.; Henriksson, O.; Sundelin, B.
2007

Interactions between climate change and contaminants

Schiedek, D.; Sundelin, B.; Readman, J.W.; Macdonald, R.W.
2007 | Mar. Pollut. Bull. | 54

Assessing anthropogenic/hypoxia stress – a battery of biomarkers and bioindicator for marine environmental testing

Sundelin, B.; Ghorokova, E.; Jacobson, T.; Löf, M.; Lindtrsöm, M.; Halldorsson, H.; Lilja, K.; Elfwing
2007

42nd European Marine Biologists, Kiel 2007 | September 19, 2019

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