Introduction to Oxidative Stress in Aquatic Ecosystems

Abstract

A quatic ecosystems house a large biosphere of marine and freshwater organisms, highly diverse in their tolerance of fluctuations in P O 2 and temperature, two major modulators of metabolism. Often, both factors act in concert, and some of the most hypoxia-tolerant fish and molluskan species are indeed from cold-water environments. Other marine invertebrate and fish specialists thrive in the mixed waters at hydrothermal vent sites, underwater volcanic outflows where warm and hydrogen-sulfide-enriched, deoxygenated vent waters mix with colder and oxygenated oceanic waters, and temperatures and oxygen concentrations are extremely variable. Many vent species can even deal with toxic hydrogen sulfide that threatens to inhibit their mitochondrial electron transporters. More than 700 Myr of aquatic evolution have fostered a huge variety of ectothermic life-forms that can deal with the most extreme and fluctuating environmental conditions. The discovery of many fascinating underwater biota has raised an interest in the respiratory capacities of aquatic organisms and in how they deal with, from our air breathing perspective,

Proteomic responses to environmentally induced oxidative stress

“…While a proteomic approach comes with its own limitations, together these proteomic studies generate novel insights about the response of the cell to ROS from a systems perspective, the plasticity of the antioxidant proteome and the evolutionary variation of the stress proteome. For example, while early work on the enzymatic responses to oxidative stress in marine organisms mainly focused on superoxide dismutase (SOD), catalase and the glutathione system (Abele and Puntarulo, 2004;Abele et al, 2012), the proteomic analyses reviewed herein point to an important role for the thioredoxinperoxiredoxin (Trx-Prx) system, in accordance with the finding that, depending on tissue and protein concentrations, up to 90% of the ROS produced in the mitochondria are scavenged through the reactions of Prx (Cox et al, 2010).…”

“…metabolic depression, as a response to environmental stress has received some attention (Podrabsky and Hand, 2015), the response of the specific biochemical reactions producing ROS to stress have not been the focus of many studies to date. In contrast, both the enzymatic and non-enzymatic ROSscavenging systems of mitochondria have been the focus of numerous studies investigating the effect of stress (Abele et al, 2012;Halliwell and Gutteridge, 2007). Here, I will first give some background for both ROS-producing and -scavenging reactions.…”

“…ROS and antioxidant proteins (for an excellent collection of reviews, see Abele et al, 2012). While these approaches were successful in highlighting the common occurrence of the increased production of ROS with environmental stress, a systems perspective, using transcriptomic, proteomic or metabolomic approaches, which can take a broader range of transcripts, proteins or metabolites into account, possibly provides novel insights into several questions.…”

“…Furthermore, other antioxidant defenses, e.g. non-enzymatic antioxidants, also contribute to the cellular response to oxidative stress, but will not be the focus of this review, with the exception of the glutathione system (Abele et al, 2012;Estevez et al, 2002). While this review focuses on the proteomic responses in regard to oxidative stress, for a general overview of recent studies on proteomic changes in response to environmental stress, I refer to other reviews (Tomanek, 2011(Tomanek, , 2014.…”

Role of Cyclonic Storm as Natural Disaster and other Factors on Vulture Mortality in India

“…Other factors, such as problems with vulture habits and habitats, food, diseases, breeding, and natural disasters may also contribute to mortality. These external and internal factors affect the normal physiology of animals and can lead to metabolic depression and eventually to death [20]. One of the important cellular responses that create metabolic depression in animals is oxidative stress (OS), which is resulted due to the oxidation of biological macro-molecules by the overproduced reactive oxygen species (ROS) [21].…”