Living in flowing water increases resistance to ultraviolet B radiation

Abstract

Ultraviolet B radiation (UV-B) is an important environmental driver that can affect locomotor performance negatively by inducing production of reactive oxygen species (ROS). Prolonged regular exercise increases antioxidant activities, which may alleviate the negative effects of UV-B-induced ROS. Animals naturally performing exercise, such as humans performing regular exercise or fish living in flowing water, may therefore be more resilient to the negative effects of UV-B. We tested this hypothesis in a fully factorial experiment, where we exposed mosquitofish (Gambusia holbrooki) to UV-B and control (no UV-B) conditions in flowing and still water. We show that fish exposed to UV-B and kept in flowing water had increased sustained swimming performance (U crit ), increased antioxidant defences (catalase activity and glutathione concentrations) and reduced cellular damage (lipid peroxidation and protein carbonyl concentrations) compared with fish in still water. There was no effect of UV-B or water flow on resting or maximal rates of oxygen consumption. Our results show that environmental water flow can alleviate the negative effects of UV-Binduced ROS by increasing defence mechanisms. The resultant reduction in ROS-induced damage may contribute to maintain locomotor performance. Hence, the benefits of regular exercise are 'transferred' to improve resilience to the negative impacts of UV-B. Ecologically, the mechanistic link between responses to different habitat characteristics can determine the success of animals. These dynamics have important ecological connotations when river or stream flow changes as a result of weather patterns, climate or human modifications.

Water flow and temperature interact to determine oxidative status, swimming performance, and dispersal of mosquitofish (Gambusia holbrooki)

“…In previous experiments (Ghanizadeh Kazerouni et al., 2017), we verified the efficacy of the flow treatment by filming tail beat frequencies of fish in flow and still water treatments. Tail beat frequency in the flow tanks was 7.87 ± 0.15 [ SE ] beats/s and in the still water treatment it was 0.75 ± 0.10 [ SE ] beats/s (Ghanizadeh Kazerouni et al., 2017). Animals were acclimated to the different flow and temperature conditions for 3–4 weeks.…”

“…We chose this acclimation period based on our previous experiments, which showed significant acclimation responses to temperature and flowing water in antioxidant responses, locomotor performance, and metabolism in G . holbrooki after 3 weeks of acclimation (Ghanizadeh Kazerouni et al., 2017; Seebacher et al., 2014). All fish were of similar size at the end of the acclimation treatments (flowing water, 18°C acclimation: mass = 0.16 ± 0.011 [ SE ] g, length = 21.13 ± 0.48 mm; flowing water, 28°C acclimation: mass = 0.16 ± 0.010 [ SE ] g, length = 21.15 ± 0.45 mm; still water, 18°C acclimation: mass = 0.16 ± 0.010 [ SE ] g, length = 21.58 ± 0.45 mm; still water, 28°C acclimation: mass = 0.16 ± 0.011 [ SE ] g, length = 21.17 ± 0.57 mm).…”

“…As a result, water flow may induce a training effect that alters muscle contractile function and metabolism and thereby locomotor capacity and behaviour (Simmonds & Seebacher, 2017; Sinclair et al., 2014). Additionally, consistent exercise stimulates anti‐oxidant defences (Steinbacher & Eckl, 2015), so that fish in flowing water may experience less damage from reactive oxygen species (ROS) than individuals from low flow or still water environments (Ghanizadeh Kazerouni et al., 2017). Oxidative damage has a negative impact on muscle function and exercise performance (Reid, 2016), and environmentally induced differences in oxidative status may thereby affect locomotor traits such as dispersal (Récapet et al., 2016).…”

“…The interactions between water flow and oxidative status are further modified by temperature. Locomotor performance and dispersal, and ROS production are sensitive to temperature changes (Ghanizadeh Kazerouni et al., 2017; Le Roy & Seebacher, 2018; Lushchak, 2011). Temperature affects physiological responses at different time scales.…”

Effects of Curcumin on the Renal Toxicity Induced by Ochratoxin A in Rats

“…These activities were expressed as unit for milligrams of proteins (U/mg of proteins). Malondialdehyde (MDA), a marker of lipid peroxidation, was calculated according to Ensiyeh Ghanizadeh-Kazeroun et al [26] and following the manufacturer's instructions. The optical density (OD) of the supernatants was read by a spectrophotometer at a wavelength of 532 nm and was expressed in nmoles of MDA for milligrams of proteins.…”