Comp Biochem Physiol A Mol Integr Physiol
October 2024
Animals routinely encounter environmental (e.g., high temperatures and hypoxia) as well as physiological perturbations (e.
View Article and Find Full Text PDFOxygen (O2) is required for aerobic energy metabolism but can produce reactive oxygen species (ROS), which are a wide variety of oxidant molecules with a range of biological functions from causing cell damage (oxidative distress) to cell signalling (oxidative eustress). The balance between the rate and amount of ROS generated and the capacity for scavenging systems to remove them is affected by several biological and environmental factors, including oxygen availability. Ectotherms, and in particular hypoxia-tolerant ectotherms, are hypothesized to avoid oxidative damage caused by hypoxia, although it is unclear whether this translates to an increase in ecological fitness.
View Article and Find Full Text PDFLaboratory-based research dominates the fields of comparative physiology and biomechanics. The power of lab work has long been recognized by experimental biologists. For example, in 1932, Georgy Gause published an influential paper in Journal of Experimental Biology describing a series of clever lab experiments that provided the first empirical test of competitive exclusion theory, laying the foundation for a field that remains active today.
View Article and Find Full Text PDFDuring the century of Journal of Experimental Biology's existence, science communication has established itself as an interdisciplinary field of theory and practice. Guided by my experiences as a scientist and science writer, I argue that science communication skills are distinct from scientific communication skills and that engaging in science communication is particularly beneficial to early-career researchers; although taking on these dual roles is not without its difficulties, as I discuss in this Perspective. In the hope of encouraging more scientists to become science communicators, I provide: (i) general considerations for scientists looking to engage in science communication (knowing their audience, storytelling, avoiding jargon) and (ii) specific recommendations for crafting effective contributions on social media (content, packaging, engagement), an emerging, accessible and potentially impactful mode of science communication.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
November 2023
Following the parasitic juvenile phase of their life cycle, sea lamprey (Petromyzon marinus) mature into a reproductive but rapidly aging and deteriorating adult, and typically die shortly after spawning in May or June. However, pre-spawning upstream migrant sea lamprey can be maintained for several months beyond their natural lifespan when held in cold water (∼4-8 °C) under laboratory conditions. We exploited this feature to investigate the interactions between senescence, oxidative stress, and metabolic function in this phylogenetically ancient fish.
View Article and Find Full Text PDFShallow or near-shore environments, such as ponds, estuaries and intertidal zones, are among the most physiologically challenging of all aquatic settings. Animals inhabiting these environments experience conditions that fluctuate markedly over relatively short temporal and spatial scales. Living in these habitats requires the ability to tolerate the physiological disturbances incurred by these environmental fluctuations.
View Article and Find Full Text PDFInvasive sea lampreys in the Laurentian Great Lakes are controlled by applying TFM (3-trifluoromethyl-4-nitrophenol) and niclosamide to streams infested with their larvae. Both agents uncouple oxidative phosphorylation in the mitochondria, but TFM specifically targets lampreys, which have a lower capacity to detoxify the lampricide. Niclosamide lacks specificity and is more potent than TFM.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
November 2021
We investigated whether fish can make dynamic haematological adjustments to support aerobic metabolism during repeated cycles of hypoxia-reoxygenation. Killifish were acclimated to normoxia, constant hypoxia (2 kPa O), or intermittent cycles of nocturnal hypoxia (12 h of normoxia: 12 h of 2 kPa O hypoxia) for 28 days. Normoxia-acclimated fish were sampled in the daytime in normoxia and after exposure to a single bout of nocturnal hypoxia.
View Article and Find Full Text PDFHypoxia is common in aquatic environments, and exposure to hypoxia followed by re-oxygenation is often believed to induce oxidative stress. However, there have been relatively few studies of reactive oxygen species (ROS) homeostasis and oxidative status in fish that experience natural hypoxia-re-oxygenation cycles. We examined how exposure to acute hypoxia (2 kPa O) and subsequent re-oxygenation (to 20 kPa O) affects redox status, oxidative damage and anti-oxidant defenses in estuarine killifish (), and whether these effects were ameliorated or potentiated by prolonged (28 days) acclimation to either constant hypoxia or intermittent cycles of nocturnal hypoxia (12 h:12 h normoxia:hypoxia).
View Article and Find Full Text PDFThe decision of where to rear young is influenced by both the needs of offspring and the costs parents incur in certain rearing environments. Plainfin midshipman fish () provide extended paternal care in rocky intertidal zones, where they experience regular bouts of aquatic hypoxia and air exposure during low-tide events. We investigated the physiological responses of plainfin midshipman males to three conditions for 6 h that simulate what these fish naturally experience during tidal cycles while nesting: normoxia, progressive hypoxia, or air exposure.
View Article and Find Full Text PDFHypoxia is a pervasive stressor in aquatic environments, and both phenotypic plasticity and evolutionary adaptation could shape the ability to cope with hypoxia. We investigated evolved variation in hypoxia tolerance and the hypoxia acclimation response across fundulid killifishes that naturally experience different patterns of hypoxia exposure. We compared resting O consumption rate ( ), and various indices of hypoxia tolerance [critical O tension (), regulation index (RI), O tension ( ) at loss of equilibrium () and time to LOE () at 0.
View Article and Find Full Text PDFComp Biochem Physiol C Toxicol Pharmacol
October 2019
Effluent from wastewater treatment plants (WWTP) contains a complex mixture of contaminants and is a major worldwide source of aquatic pollution. We examined the effects of exposure to treated effluent from a municipal WWTP on the metabolic physiology of bluegill sunfish (Lepomis macrochirus). We studied fish that were wild-caught or experimentally caged (28 d) downstream of the WWTP, and compared them to fish that were caught or caged at clean reference sites.
View Article and Find Full Text PDFMany fish experience daily cycles of hypoxia in the wild, but the physiological strategies for coping with intermittent hypoxia are poorly understood. We examined how killifish adjust O supply and demand during acute hypoxia, and how these responses are altered after prolonged acclimation to constant or intermittent patterns of hypoxia exposure. We acclimated killifish to normoxia (∼20 kPa O), constant hypoxia (2 kPa) or intermittent cycles of nocturnal hypoxia (12 h:12 h normoxia:hypoxia) for 28 days, and then compared whole-animal O consumption rates ( ) and tissue metabolites during exposure to 12 h of hypoxia followed by reoxygenation in normoxia.
View Article and Find Full Text PDFThe aim of the present study was to determine the roles of externally versus internally oriented CO/H-sensitive chemoreceptors in promoting cardiorespiratory responses to environmental hypercarbia in the facultative air-breathing fish, Chitala ornata (the clown knifefish). Fish were exposed to environmental acidosis (pH ~ 6.0) or hypercarbia (≈ 30 torr PCO) that produced changes in water pH equal to the pH levels of the acidotic water to distinguish the relative roles of CO versus H.
View Article and Find Full Text PDFAnimals are bombarded with information about their environment and must select and interpret the relevant cues to make behavioral adjustments critical to survival. How animals integrate and balance the many signals they receive about their environment is rarely assessed. We investigated how signals from the social and physical environment interact to influence environmental preferences in the endemic Tanganyikan cichlid Neolamprologus pulcher.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
August 2016
Hypoxia tolerance is a plastic trait, and can vary between species. We compared hypoxia tolerance (hypoxic loss of equilibrium, LOE, and critical O2 tension, Pcrit) and traits that dictate O2 transport and metabolism in pumpkinseed (Lepomis gibbosus), bluegill (L. macrochirus), and the naturally occurring hybrid in different acclimation environments (wild versus lab-acclimated fish) and at different temperatures.
View Article and Find Full Text PDFMany fish encounter hypoxia in their native environment, but the role of mitochondrial physiology in hypoxia acclimation and hypoxia tolerance is poorly understood. We investigated the effects of hypoxia acclimation on mitochondrial respiration, O2kinetics, emission of reactive oxygen species (ROS), and antioxidant capacity in the estuarine killifish ( ITALIC! Fundulus heteroclitus). Killifish were acclimated to normoxia, constant hypoxia (5 kPa O2) or intermittent diel cycles of nocturnal hypoxia (12 h:12 h normoxia:hypoxia) for 28-33 days and mitochondria were isolated from liver.
View Article and Find Full Text PDFMany fish encounter hypoxia on a daily cycle, but the physiological effects of intermittent hypoxia are poorly understood. We investigated whether acclimation to constant (sustained) hypoxia or to intermittent diel cycles of nocturnal hypoxia (12 h normoxia:12 h hypoxia) had distinct effects on hypoxia tolerance or on several determinants of O2 transport and O2 utilization in estuarine killifish. Adult killifish were acclimated to normoxia, constant hypoxia, or intermittent hypoxia for 7 or 28 days in brackish water (4 ppt).
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