Project description:Abstract Ocean warming elevates metabolic rates in marine ectotherms but often constrains energetic resources, causing an imbalance between supply and demand. Transient hypoxia is near-ubiquitous across the world’s coral reefs and may exacerbate this imbalance, yet its effects on the energetics of reef fishes remain poorly understood. In this study, we assess the metabolic costs incurred by a cryptobenthic reef fish exposed to oxygen fluxes measured on the world’s hottest coral reefs in the Arabian/Persian Gulf. Hypoxia-exposure induced an 8.67% increase in aerobic metabolic rate over the six hours following reoxygenation, and resulted in an estimated 2.87% increase in total daily metabolic rate (mg O2 kg -1 day-1). This energetic cost did not coincide with detectable changes in anaerobic metabolism but was accompanied by increased activity during reoxygenation and a strong, acute transcriptomic response in genes related to oxygen-sensing. Oxygen availability on the reefs declined below the threshold for inducing such energetic costs on over half (56.04%) of the days throughout the summer, potentially leading to substantial cumulative costs. Such energetic costs represent an additional and previously under-appreciated consequence of hypoxia in coral reef environments that may exacerbate the temperature-induced mismatches between energy supply and demand, a key balance affecting growth and fitness.
Project description:Aging is a multifactorial process that results in progressive loss of regenerative capacity and tissue function while simultaneously favoring the development of a large array of age-related diseases. Evidence suggests that the accumulation of senescent cells in tissue promotes both normal and pathological aging. Oxic stress is a key driver of cellular senescence. Because symbiotic long-lived reef corals experience daily hyperoxic and hypoxic transitions, we hypothesized that these long-lived animals have developed specific longevity strategies in response to light. We analyzed transcriptome variation in the reef coral Stylophora pistillata during the day–night cycle and revealed a signature of the FoxO longevity pathway. We confirmed this pathway by immunofluorescence using antibodies against coral FoxO to demonstrate its nuclear translocation. Among genes that were specifically up- or downregulated on exposure to light, human orthologs of two “light-up” genes (HEY1 and LONF3) exhibited anti-senescence properties in primary human fibroblasts. Therefore, these genes are interesting candidates for counteracting skin aging. We propose a large screen for other light-up genes and an investigation of the biological response of reef corals to light (e.g., metabolic switching) to elucidate these processes and identify effective interventions for promoting healthy aging in humans.