Biology subjects

Sourisse, J. M.

Publications and source records attributed to Sourisse, J. M..

4 recordsLinked to original sources

bioRxiv2024

Parental thermal conditions affect the brain activity response to alarm cue in larval zebrafish

With temperature being a crucial factor affecting the physiology of ectothermic animals, global warming will likely impact neural mechanisms aquatic organisms use to perceive their environment over generations. However, exposure to elevated temperature during specific life stages and across generations may confer fish resilience through phenotypic plasticity. In this study, we investigate the effects of developmental and parental temperature on brain activity response to an olfactory cue in the larval zebrafish, Danio rerio. We exposed parents during reproduction and their offspring during development to control (28{degrees}C) or elevated temperature (30{degrees}C) and observed the response of the larval telencephalon to an alarm cue using live calcium imaging. Parental exposure to elevated temperature decreased the time till maximum brain activity response regardless of the offsprings developmental temperature, revealing that parental thermal conditions can affect the excitability of the offsprings neural circuitry. Furthermore, brain activity duration was affected by the interaction between parental and offspring thermal conditions, tending to last longer when either parents or offspring were exposed to elevated temperature, yet more similar to control when elevated temperature was experienced by both parents and offspring. This could represent an anticipatory parental effect influencing the offsprings brain response to match the parental environment, or an early developmental effect occurring within a susceptible short time window post-fertilization. Overall, our results suggest that future predicted warming can alter processes involved in brain transmission and show that parental conditions could aid in the preparation of their offspring to respond to olfactory stimuli in a changing environment.

physiology↗

bioRxiv2023

Warming affects routine swimming activity and novel odour molecular response in larval zebrafish

Temperature is a primary factor affecting the survival, development, and physiology of aquatic ectothermic animals and global warming of water bodies may therefore impact several biological levels of aquatic life. Understanding the effects of near-future predicted temperature changes on the behaviour and the underlying molecular mechanisms of aquatic animals is of particular importance, since behaviour mediates key interactions and, in turn, population dynamics. In this study, we investigate the effects of elevated developmental temperature on locomotor behaviour and olfactory learning in the zebrafish, Danio rerio. We exposed zebrafish from cleavage embryonic stage to either current day control (28{degrees}C) or predicted future elevated temperature (30{degrees}C) for seven days. Overall, warming reduced the total routine swimming distance and caused the upregulation of a small number of genes involved in metabolism and neuron development, suggesting accelerated development at elevated temperature. When fish were exposed to two different olfactory cues, namely catfish cue, a non-alarming but novel odour, and injured conspecifics alarm cue expected to cause a fear reaction, warming differently affected larvae response to the two cues. In particular, a large transcriptional reprogramming was observed at elevated temperature in response to novel odour exposure, with upregulation of cell signalling, neuron development and neuron functioning genes. As this response was coupled with downregulation of genes involved in protein translation and ATP metabolism, it indicates that novel odour recognition in future-predicted thermal conditions will require energetic trade-offs between expensive baseline processes and responsive functions. To also evaluate their learning abilities at both temperatures, 7 days post fertilization (dpf) zebrafish were conditioned with a mixture of injured conspecifics alarm cue and non-alarming catfish cue. Regardless of temperature, no behavioural (freezing) nor gene expression changes were detected, reinforcing our previous findings that warming mainly affects zebrafish molecular response to novel odours. Overall, our results show that future thermal conditions will likely impact developing stages, causing energy trade-offs following olfactory detection of novel substances in the environment.

molecular biology↗

bioRxiv2022

Long non-coding RNA as environmental regulator in a non-model fish

The majority of the transcribed genome does not have coding potential but is composed of non-coding transcripts that are involved in transcriptional and post-transcriptional regulation of protein-coding genes. Regulation of gene expression is important in determining the response of organisms to changes in the environment, and therefore their persistence as population or species under global change. However, long non-coding RNAs (lncRNAs) are scarcely studied especially in non-model organisms due to the lack of a reliable pipeline for their accurate identification and annotation. Here, we present a pipeline which uses a combination of alignment-dependent and independent methods for the identification of conserved and species-specific lncRNAs from RNA-Seq data. Validation of this pipeline was performed using existing RNA-Seq data from Acanthochromis polyacanthus brain tissue, identifying a total of 4,728 lncRNAs across the genome, the majority of which (3,272) are intergenic. To investigate the possible implications of these intergenic lncRNAs (lincRNAs), we estimated the expression changes of lincRNAs and coding genes in response to ocean acidification. We found lincRNAs which neighbour or possibly trans-regulate differentially expressed coding genes related to pH regulation, neural signal transduction and ion transport, which are known to be important in the response to ocean acidification in fish. Overall, this pipeline enables the use of existing RNA sequencing data to reveal additional underlying molecular mechanisms involved in the response to environmental changes by integrating the study of lncRNAs with gene expression.

molecular biology↗

bioRxiv2020

The gut microbiome stability of a butterflyfish is disrupted on severely degraded Caribbean coral reefs

Environmental degradation has the potential to alter key mutualisms that underline the structure and function of ecological communities. While it is well recognized that the global loss of coral reefs alters fish communities, the effects of habitat degradation on microbial communities associated with fishes remain largely unknown despite their fundamental roles in host nutrition and immunity. Using a gradient of reef degradation, we show that the gut microbiome of a facultative, coral-feeding butterflyfish (Chaetodon capistratus) is significantly more variable among individuals at degraded reefs with very low live coral cover (~0%) than reefs with higher coral cover (~30%), mirroring a known pattern of microbial imbalance observed in immunodeficient humans and other stressed or diseased animals. We demonstrate that fish gut microbiomes on severely degraded reefs have a lower abundance of Endozoicomonas and a higher diversity of anaerobic fermentative bacteria, which suggests a broader and less coral dominated diet. The observed shifts in fish gut bacterial communities across the habitat gradient extend to a small set of potentially beneficial host associated bacteria (i.e., the core microbiome) suggesting essential fish-microbiome interactions are vulnerable to severe coral degradation.

ecology↗