Warming During Embryogenesis Induces a Lasting Transcriptomic Signiture in Fishes
Ontology highlight
ABSTRACT: RNA-seq of ventricles from 6 Scyliorhinus canicula juveniles (~5 months old) that underwent embryogenesis at 15C or 20C and were held at 15C post-hatching.
Project description:Gene expression profiling of pooled late stage embryos from Leucoraja erinacea, Scyliorhinus canicula and Callorhinchus milii show that HOXC cluster genes are not expressed in the two elasmobranch fishes, L. erinacea and S. canicula. This finding supports the observations that these genes are not found in whole genome shotgun sequencing of L. erinacea or genomic clones from S. canicula. Profile gene expression in pooled late stage embryos from three species (L. erinacea, S. canicula and C. milii)
Project description:Gene expression profiling of pooled late stage embryos from Leucoraja erinacea, Scyliorhinus canicula and Callorhinchus milii show that HOXC cluster genes are not expressed in the two elasmobranch fishes, L. erinacea and S. canicula. This finding supports the observations that these genes are not found in whole genome shotgun sequencing of L. erinacea or genomic clones from S. canicula.
Project description:Transcriptome analyses on seeds developed in different parental conditions investigating the effect of the parental environment on the transcriptome of dry seeds of three different genotypes RNA isolated from freshly harvested dry seed of three genotypes, the near isogenic line of DELAY OF GEMRMINATION 1 (DOG1), DOG3 and DOG6, grown in 15°C, 20°, low nitrate (N0), low light (LL) and SL (standard light). Please note that SL (standard light) is the control for the LL (low light), and 20C is the control for both 15C and low nitrate (N0).
Project description:Climate change poses a significant threat to global biodiversity, but freshwater fishes have been largely ignored in climate change assessments. Here, we assess threats of future flow and water temperature extremes to ~11,500 riverine fish species. In a 3.2 °C warmer world (no further emission cuts after current governments' pledges for 2030), 36% of the species have over half of their present-day geographic range exposed to climatic extremes beyond current levels. Threats are largest in tropical and sub-arid regions and increases in maximum water temperature are more threatening than changes in flow extremes. In comparison, 9% of the species are projected to have more than half of their present-day geographic range threatened in a 2 °C warmer world, which further reduces to 4% of the species if warming is limited to 1.5 °C. Our results highlight the need to intensify (inter)national commitments to limit global warming if freshwater biodiversity is to be safeguarded.
Project description:Declining body size has been suggested to be a universal response of organisms to rising temperatures, manifesting at all levels of organization and in a broad range of taxa. However, no study to date evaluated whether deforestation-driven warming could trigger a similar response. We studied changes in fish body size, from individuals to assemblages, in streams in Southeastern Amazonia. We first conducted sampling surveys to validate the assumption that deforestation promoted stream warming, and to test the hypothesis that warmer deforested streams had reduced fish body sizes relative to cooler forest streams. As predicted, deforested streams were up to 6 °C warmer and had fish 36% smaller than forest streams on average. This body size reduction could be largely explained by the responses of the four most common species, which were 43-55% smaller in deforested streams. We then conducted a laboratory experiment to test the hypothesis that stream warming as measured in the field was sufficient to cause a growth reduction in the dominant fish species in the region. Fish reared at forest stream temperatures gained mass, whereas those reared at deforested stream temperatures lost mass. Our results suggest that deforestation-driven stream warming is likely to be a relevant factor promoting observed body size reductions, although other changes in stream conditions, like reductions in organic matter inputs, can also be important. A broad scale reduction in fish body size due to warming may be occurring in streams throughout the Amazonian Arc of Deforestation, with potential implications for the conservation of Amazonian fish biodiversity and food supply for people around the Basin.
Project description:In the present study, we were interested in gene expression changes in the pectoralis muscle of juvenile king penguins during the transition from terrestrial to marine life. Strictly terrestrial during their first year after hatching, king penguin chicks must then depart to sea to reach nutritional emancipation and pectoralis muscle is largely involved in penguin adaptation to the marine environment. To compare these transcriptomic profiles, we realized heterologous hybridization on Affymetrix GeneChip Chicken Genome Arrays, as the chicken is the closest model species for which microarrays are available. The development of a new algorithm, MaxRS, allow us to determine differentially expressed genes implicated in energetic metabolism or involved in cellular defense against reactive oxygen species and associated injuries. We compared muscle sample biopsy from 4 penguin juveniles captured just before they undergone their first immersion to cold water (named NI for Never Immersed) and 3 penguin juveniles that had completly accomplished their acclimation to marine life (named SA for Sea Acclimated).
Project description:Most marine fish species express life-history changes across temperature gradients, such as faster growth, earlier maturation, and higher mortality at higher temperature. However, such climate-driven effects on life histories and population dynamics remain unassessed for most fishes. For 332 Indo-Pacific fishes, we show positive effects of temperature on body growth (but with decreasing asymptotic length), reproductive rates (including earlier age-at-maturation), and natural mortality for all species, with the effect strength varying among habitat-related species groups. Reef and demersal fishes are more sensitive to temperature changes than pelagic and bathydemersal fishes. Using a life table, we show that the combined changes of life histories upon increasing temperature tend to facilitate population growth for slow life-history populations, but reduce it for fast life-history ones. Within our data, lower proportions (25-30%) of slow life-history fishes but greater proportions of fast life-history fishes (42-60%) show declined population growth rates under 1 °C warming. Together, these findings suggest prioritizing sustainable management for fast life-history species.
Project description:In this work, we describe the transcriptional profiles of adapted and non-adapted one-month-old Baikal whitefish juveniles after heat shock exposure. Preadapted fish were exposed to a repeated thermal rise of 6 °C above control temperature every 3 days throughout embryonic development. One month after hatching, preadapted and non-adapted larvae were either maintained at control temperatures (12 °C) or exposed to an acute thermal stress (TS) of 12 °C above control temperature. The information on transcriptional profiles will contribute to further understanding of the mechanisms of adaptation of whitefish to the environment.
Project description:We investigated whether fatigue from sustained aerobic swimming provides a sub-lethal endpoint to define tolerance of acute warming in fishes, as an alternative to loss of equilibrium (LOE) during a critical thermal maximum (CTmax) protocol. Two species were studied, Nile tilapia (Oreochromis niloticus) and pacu (Piaractus mesopotamicus). Each fish underwent an incremental swim test to determine gait transition speed (UGT), where it first engaged the unsteady anaerobic swimming mode that preceded fatigue. After suitable recovery, each fish was exercised at 85% of their own UGT and warmed 1°C every 30 min, to identify the temperature at which they fatigued, denoted as CTswim Fish were also submitted to a standard CTmax, warming at the same rate as CTswim, under static conditions until LOE. All individuals fatigued in CTswim, at a mean temperature approximately 2°C lower than their CTmax Therefore, if exposed to acute warming in the wild, the ability to perform aerobic metabolic work would be constrained at temperatures significantly below those that directly threatened survival. The collapse in performance at CTswim was preceded by a gait transition qualitatively indistinguishable from that during the incremental swim test. This suggests that fatigue in CTswim was linked to an inability to meet the tissue oxygen demands of exercise plus warming. This is consistent with the oxygen and capacity limited thermal tolerance (OCLTT) hypothesis, regarding the mechanism underlying tolerance of warming in fishes. Overall, fatigue at CTswim provides an ecologically relevant sub-lethal threshold that is more sensitive to extreme events than LOE at CTmax.