Oxidative Stress in Sulfidic Habitats

Joyner-Matos, Joanna; Julian, David

doi:10.1002/9781444345988.ch7

Cited by 1 publication

(2 citation statements)

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“…Indeed, the presence of sulphide in the alvinellid environm ent can also affect the respiration process by inhibiting the complex IV cytochrome oxidase, potentially leading to an increase in endogenous ROS production, as previously observed in the shallow-w ater annelids Arenicola marina and Glyc era dibranchiate (Abele-Oeschger 1996, Völkel & G rieshaber 1997, Julian et al 2005, Joyner-M atos & Julian 2011. The possible im pact of high endogen ous ROS production by cellular respiration on the expression of antioxidant enzymes has not yet been considered in hydrotherm al vent organisms.…”

Section: Introductionmentioning

confidence: 78%

“…O ther sources of 0 2'~, not directly associated with the respiratory chain, m ight thus be responsible for set ting the expression level of SOD betw een tissues. High SOD activities are often linked to the presence of haem oglobin in invertebrates, possibly reflecting the tendency of these respiratory pigm ents to form 0 2'~ via autoxidation (Abele-Oeschger & O eschger 1995, A bele-O eschger 1996, Joyner & Julian, 2011. It is thus possible that high SOD activity could be re quired for neutralising superoxide associated with the oxidation of haemoglobin, particularly abundant in alvinellids.…”

Section: A Ntioxidant Abilities Of a Lvinella Pom Pejanamentioning

confidence: 99%

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Living in a hot redox soup: antioxidant defences of the hydrothermal worm Alvinella pompejana

Genard¹,

Marie²,

Loumaye³

et al. 2013

Aquat. Biol.

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T his authors' personal cop y m ay not be publicly o r syste m a tica lly copied or distributed, o r posted on the O pen W eb, exce pt w ith w ritten perm ission o f th e co p yrig h t holder(s). It m ay be distributed to interested individuals on request. ABSTRACT: The hydrotherm al Pompeii worm Alvinella pom pejana lives very close to the walls of black smokers and is therefore exposed to high-tem perature venting fluid containing high con centrations of sulphides and metals. The highly aerobic m etabolism of these annelids, together with these extrem e physico-chemical conditions, theoretically accelerates redox processes in and around the worm, potentially increasing oxidative threat by reactive oxygen species (ROS). This prom pted us to analyse activity of antioxidant enzymes in A. pom pejana tissues and investigate w hether they are adjusted to the endogenous production of ROS by oxidative phosphorylations and/or to the environm ental conditions. This was investigated by com paring antioxidant and m etabolic enzyme activities in gills, head, body wall, pygidium and guts of A. pom pejana col lected at different vent sites of the East Pacific Rise. The antioxidant defence arsenal of A. p o m p e jana is peculiar, showing very low catalase (CAT) activity and very high superoxide dism utase (SOD) activity in most tissues. It is very likely that CAT is not expressed in A. pom pejana, as this haem ic enzyme could be inhibited by the high sulphide concentrations prevailing in the worm's environm ent. A. pom pejana does not com pensate for the low hydrogen peroxide scavenging activity of CAT by higher glutathione peroxidase (GPX) activity levels. This latter enzyme corre lates well with cytochrome c oxidase and citrate synthase in most tissues, suggesting that oxida tive m etabolism represents the m ain source of peroxides m anaged by GPX. On the contrary, SOD shows no correlation with any metabolic enzyme and is likely adjusted to respiration-independent ROS generation. Source variations in enzyme activities are mainly observed in the anim al's gills and gut, possibly reflecting differences in the vent fluid therm al regim e and/or chemistry.

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Section: Introductionmentioning

confidence: 78%

Section: A Ntioxidant Abilities Of a Lvinella Pom Pejanamentioning

confidence: 99%