Effect of acute cadmium exposure on oxidative stress and antioxidant system of the scallop Aequipecten tehuelchus.

This study aimed to assess the impact of acute exposure (96 h) to Cd in gills, digestive gland and muscle of the Tehuelche scallop Aequipecten tehuelchus from San José gulf in Patagonia, Argentina. Scallops were exposed to Cd concentrations of 0, 25, 50, 100, 150, 204, 275, 371, and 500 μg/L, and mortality rates were recorded after 96 h of exposure. Surviving organisms were analyzed for the biochemical response through reactive oxygen and nitrogen species (RONS), activities of catalase (CAT) and glutathione-S-transferase (GST), metallothioneins (MT), lipid peroxidation (LPO) and liposoluble antioxidants α-tocopherol (α-T) and β-carotene (β-C).

Biochemical response and tissue-specific accumulation of scallop Aequipecten tehuelchus from Patagonia, Argentina after exposure to inorganic arsenic.

This study investigates the effects of different inorganic arsenic (As III) concentrations (0, 125, 500 and 1000 μg As/L) following two exposure times (7 and 14 days) on gills, digestive gland and muscle of scallop Aequipecten tehuelchus from Patagonia, Argentina. A biochemical approach was used to investigate oxidative stress-related parameters after different As concentrations and exposure times. Although the accumulation of As was of the same order of magnitude in all tissues, the results showed distinct tissue-specific oxidative responses to this metalloid.

Evidences of metabolic alterations and cellular damage in different tissues of scallops Aequipecten tehuelchus exposed to cadmium.

Scallops Aequipecten tehuelchus (Patagonia, Argentina) were exposed to 0, 2, 5 and 12 μg Cd/L for 7 and 14 days, causing in digestive gland a significant production of reactive oxygen and nitrogen species (RONS), induction of catalase (CAT) and glutathione S-transferase (GST) activities and metallothioneins (MT) synthesis. In gills, there was inhibition of GST and induction of CAT, MT and α-tocopherol (α-Toc). In muscle, a significant increment of MT was also registered and inhibition of CAT.

Changes in the oxidative status and damage by non-essential elements in the digestive gland of the gastropod .

The freshwater gastropod fulfills the ideal conditions of a bioindicator species since its digestive gland bioconcentrates elements toxic for human and ecosystems health. The aim of this work was to study the balance between production of free radicals and antioxidant defenses, and the generation of oxidative damage in the digestive gland of this mollusk after exposure (96 h) to three elements with differential affinities for functional biological groups: mercury (5.5 μg/L of Hg as HgCl), arsenic [500 μg/L of (AsO) as NaAsO7HO], or uranium [700 μg/L of (UO) as UO(CHCOOH)].

Ocean acidification and seasonal temperature extremes combine to impair the thermal physiology of a sub-Antarctic fish.

To predict the potential impacts of climate change on marine organisms, it is critical to understand how multiple stressors constrain the physiology and distribution of species. We evaluated the effects of seasonal changes in seawater temperature and near-future ocean acidification (OA) on organismal and sub-organismal traits associated with the thermal performance of Eleginops maclovinus, a sub-Antarctic notothenioid species with economic importance to sport and artisanal fisheries in southern South America. Juveniles were exposed to mean winter and summer sea surface temperatures (4 and 10 °C) at present-day and near-future pCO levels (~500 and 1800 μatm).

Physiological responses and specific fatty acids composition of Microcystis aeruginosa exposed to total solar radiation and increased temperature.

The combined effects of increased temperature and solar ultraviolet radiation (UVR, 280-400 nm) on M. aeruginosa cultures was analyzed in terms of cell abundance, reactive oxygen and nitrogen species (ROS/RNS), antioxidant activity of catalase (CAT), superoxide dismutase (SOD), glutathione S transferase (GST), fatty acids (FA) content and lipid damage. After 12 days exposure to high temperature (29 °C), cells were exposed to solar UVR (4 h).

Differential sensitivity of fatty acids and lipid damage in Microcystis aeruginosa (cyanobacteria) exposed to increased temperature.

Changes in fatty acid (FA) composition can mean a mechanism of acclimation of Cyanobacteria to climate change. The objective of the present study was to evaluate the effects of increased temperature on M. aeruginosa cultures in terms of FA content, lipid damage, biomass and reactive oxygen species (ROS).

Assessment of oxidative balance in hydrophilic cellular environment in Chlorella vulgaris exposed to glyphosate.

The studied hypothesis is that glyphosate (GLY) can affect the oxidative balance in the hydrophilic intracellular medium in non-target Chlorella vulgaris cells. Analytical GLY (5 μM) and a commercial product (RUP) (5 μM) supplementation, did not affect the growth profile. Neither in latent (Lag) nor in exponential (Exp) phase of development, there were significant differences in the cellular abundance, evaluated as cell number, after the supplementation with GLY or RUP.

Multiple-Biomarker Approach in a Commercial Marine Scallop from San Jose gulf (Patagonia, Argentina) for Health Status Assessment.

The health status of the commercial Tehuelche scallop Aequipecten tehuelchus from San Román and El Riacho in San José gulf (Patagonia, Argentina) was evaluated through biomarkers widely used in ecotoxicological applications. Natural levels of arsenic (As) and cadmium (Cd) were measured to determine their potential relationships with fluctuations of several oxidative stress biomarkers in the scallop. Oxidative biomarkers, such as catalase (CAT), glutathione S-transferase (GST), superoxide dismutase (SOD), metallothioneins (MT), reactive oxygen species (ROS), α-tocopherol (α-T), and lipid peroxidation (LPO) through thiobarbituric acid reactive substances (TBARS) and lipid radical (LR), were measured in gills, digestive gland, and muscle of Tehuelche scallop in winter (August 2015) and summer (January 2016).

Physiological responses and toxin production of Microcystis aeruginosa in short-term exposure to solar UV radiation.

The aim of this study was to evaluate the effects of short-term (hours) exposure to solar UV radiation (UVR, 280-400 nm) on the physiology of Microcystis aeruginosa. Three solar radiation treatments were implemented: (i) PAR (PAR, 400-700 nm), (ii) TUVA (PAR + UVAR, 315-700 nm) and (iii) TUVR (PAR + UVAR + UVBR, 280-700 nm). Differential responses of antioxidant enzymes and the reactive oxygen species (ROS) production to UVR were observed.

Free radical production and antioxidant status in brain cortex non-synaptic mitochondria and synaptosomes at alcohol hangover onset.

Alcohol hangover (AH) is the pathophysiological state after a binge-like drinking. We have previously demonstrated that AH induced bioenergetics impairments in a total fresh mitochondrial fraction in brain cortex and cerebellum. The aim of this work was to determine free radical production and antioxidant systems in non-synaptic mitochondria and synaptosomes in control and hangover animals.

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

Microcystis are known for their potential ability to synthesize toxins, mainly microcystins (MCs). In order to evaluate the effects of temperature on chlorophyll a (Chl a), growth, physiological responses and toxin production of a native Microcystis aeruginosa, we exposed the cells to low (23°C) and high (29°C) temperature in addition to a 26°C control treatment. Exponential growth rate was significantly higher at 29°C compared to 23°C and control, reaching 0.

Metals from mine waste as potential cause of oxidative stress in burrowing crab Neohelice granulata from San Antonio bay.

The Natural Protected Area San Antonio bay is of particular importance for its congregation of migratory shorebirds and it has been declared one of the Western Hemisphere Shorebird Reserve Network International site (WHSRN). Present study represents the first assessment of variation on oxidative stress biomarkers in male crab Neohelice granulata from San Antonio bay (Río Negro, Argentina) under field conditions, associated mainly to metal contamination coming from passive mining wastes. Three sites were sampled once every three months from November 2012 to August 2013 within this sea inlet (Pile, Fishery and Port) and a control site at the southeast of the bay (Punta Perdices).

Biomarkers of environmental stress in gills of ribbed mussel Aulacomya atra atra (Nuevo Gulf, Northern Patagonia).

In this study, we assessed in gills of native ribbed mussels Aulacomya atra atra from three sites within Nuevo Gulf (Northern Patagonia) several biomarkers such as reactive oxygen species (ROS), lipid radicals (LR), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST) and metallothionein (MT). Furthermore, concentrations of main trace metals (Fe, Al, Zn, Cu, Cd and Pb) were quantified in mussel tissue. Results showed significant induction of SOD, GST, MT and MDA, as well as, higher concentration of Fe, Al and Cd in winter than in summer.

Electronic paramagnetic resonance (EPR) for the study of ascorbyl radical and lipid radicals in marine organisms.

Electron paramagnetic resonance (EPR) spectroscopy detects the presence of radicals of biological interest, such as ascorbyl radical (A(•)) and lipid radicals. A(•) is easily detectable by EPR even in aqueous solution at room-temperature. Under oxidative conditions leading to changes in total ascorbate (AH(-)) content, the A(•)/AH(-) ratio could be used to estimate early oxidative stress in the hydrophilic milieu.

Assessment of antioxidant responses and trace metal accumulation by digestive gland of ribbed mussel Aulacomya atra atra from Northern Patagonia.

Seasonal and spatial variability of trace metal concentrations and of a battery of antioxidant parameters were evaluated in digestive gland of the ribbed mussel Aulacomya atra atra. Fe, Al and Cu accumulated in tissue exhibited maximum values in winter, coinciding partially with the highest labile concentrations of Fe and Cu in sediment. Metals, as other pollutants, are known to influence the oxidative status of organisms and antioxidant enzymes have been often proposed as biomarkers of contaminant effects.

New insights on dimethylaminoethanol (DMAE) features as a free radical scavenger.

Recently, a number of synthetic drugs used in a variety of therapeutic indications have been reported to have antiaging effects. Among them, Dimethylaminoethanol (DMAE), an anologue of dietylaminoethanol, is a precursor of choline, which in turn allows the brain to optimize the production of acetylcholine that is a primary neurotransmitter involved in learning and memory. The data presented here includes new information on the ability of the compound to scavenge specific free radicals, assessed by Electron Spectroscopic Resonance (EPR), to further analyze the role of DMAE as an antioxidant.

Seasonal and pollution-induced variations in biomarkers of transplanted mussels within the Beagle Channel.

The occurrence of biomarker variations linked to environmental factors makes it difficult to distinguish the effect of pollution. In an attempt to evaluate spatial and seasonal effects of environmental parameters on biomarker responses, mussels Mytilus edulis chilensis coming from an aquaculture farm were transplanted to several points within Ushuaia Bay (Beagle Channel) for 6 weeks in summer and winter. Activities of superoxide dismutase, catalase, glutathione-S-transferase and levels of lipid peroxidation were measured in gills and digestive gland.

The effect of seasonality on oxidative metabolism in Nacella (Patinigera) magellanica.

We studied the seasonal variation on aerobic metabolism and the response of oxidative stress parameters in the digestive glands of the subpolar limpet Nacella (P.) magellanica. Sampling was carried out from July (winter) 2002 to July 2003 in Beagle Channel, Tierra del Fuego, Argentina.

Oxidative stress in limpets exposed to different environmental conditions in the Beagle Channel.

The aim of this work was to study the oxidative profile of digestive glands of two limpets species (Nacella (Patinigera) magellanica and Nacella (Patinigera) deaurata) exposed to different environmental conditions. The intertidal population of N. (P.