Reactive oxygen species and theAntarctic macroalgal wound response

Abstract

Reactive oxygen species (ROS) are commonly produced by algal, vascular plant, and animal cells involved in the innate immune response as cellular signals promoting defense and healing and/or as a direct defense against invading pathogens. The production of reactive species in macroalgae upon injury, however, is largely uncharacterized. In this study, we surveyed 13 species of macroalgae from the Western Antarctic Peninsula and show that the release of strong oxidants is common after macroalgal wounding. Most species released strong oxidants within 1 min of wounding and/or showed cellular accumulation of strong oxidants over an hour post-wounding. Exogenous catalase was used to show that hydrogen peroxide was a component of immediate oxidant release in one of five species, but was not responsible for the entire oxidative wound response as is common in vascular plants. The other component(s) of the oxidant cocktail released upon wounding are unknown. We were unable to detect protein nitration in extracts of four oxidant-producing species flash frozen 30 s after wounding, but a role for reactive nitrogen species such as peroxynitrite cannot be completely ruled out. Two species showed evidence for the production of a catalase-activated oxidant, a mechanism previously known only from the laboratory and from the synthetic drug isoniazid used to kill the human pathogen Mycobacterium tuberculosis. The rhodophyte Palmaria decipiens, which released strong oxidants after wounding, also produced strong oxidants upon grazing by a sympatric amphipod, suggesting that oxidants are involved in the response to grazing.

The immediate wound‐induced oxidative burst of Saccharina latissima depends on light via photosynthetic electron transport

“…Although light‐dependence of wound‐induced DCFH oxidation was only quantified in these two species of Antarctic macroalgae, we also observed this light‐dependence (R. McDowell, unpublished observations) in all 13 Antarctic species previously surveyed for a wound‐induced oxidative burst (McDowell et al. ). S. latissima , A. mirabilis , and P. decipiens are species widely separated both geographically and phylogenetically.…”

“…However, without the use of catalase or other ROS "controls" the light-dependent fluorescence cannot be conclusively linked to ROS rather than direct oxidation by components of the electron transport chain. Although light-dependence of wound-induced DCFH oxidation was only quantified in these two species of Antarctic macroalgae, we also observed this lightdependence (R. McDowell, unpublished observations) in all 13 Antarctic species previously surveyed for a wound-induced oxidative burst (McDowell et al 2014a). S. latissima, A. mirabilis, and P. decipiens are species widely separated both geographically and phylogenetically.…”

Bioinspired nanocoatings for biofouling prevention by photocatalytic redox reactions

“…Several reports have focused on developing bio-inspired eco-friendly AF surfaces 13, 14 . Certain algal species defend themselves from biofouling by producing reactive oxygen species (ROS) such as hydroxyl radicals and peroxides 15–17 . This mechanism is in fact similar to the working of a photocatalytic material 18 , which led us to investigate the antifouling capabilities of nanostructured semiconductor oxides with considerable success (under visible light excitation) in both a laboratory and mesocosm settings 18, 19 .…”

Growth, toxin production, active oxygen species and catalase activity of Microcystis aeruginosa (Cyanophyceae) exposed to temperature stress

“…The membrane-permeable non-fluorescent DCFH-DA oxidation has been used for detecting several ROS in biological media (McDowell et al, 2013). Cellular esterases hydrolyze the probe to the nonfluorescent 2′,7′-dichlorodihydrofluorescein (H 2 DCF).…”