Biology subjects

Manzon, R.

Publications and source records attributed to Manzon, R..

5 recordsLinked to original sources

bioRxiv2024

Elevated temperature during rearing diminishes swimming and disturbs the metabolism of yellow perch larvae

Temperate waters, such as the Great Lakes, are predicted to increase by 1{degrees}C every decade. Poikilothermic fish thermoregulate behaviourally, moving to more suitable thermal environments. Embryos are incapable of locomotion and may be exposed to non-optimal temperatures during development. Increased temperature alters the normal development of the yellow perch (Perca flavescens), however, whether altered incubation temperature influences the development of metabolism and function in these fish remains unknown. We hypothesized that increased embryonic incubation temperature would disturb cardiac and metabolic function and the behaviour of yellow perch larvae. We reared yellow perch embryos at 12{degrees}C, 15{degrees}C, or 18{degrees}C until hatching; after hatching, the temperature was raised to a common garden 18{degrees}C, their preferred post-hatch temperature. We assessed exploratory behaviour, metabolism (oxygen consumption), and cardiac performance throughout early development. At hatch, 12{degrees}C fish exhibited the greatest swimming activity, with 18{degrees}C fish consuming the least oxygen and possibly experiencing mitochondrial dysfunction. Cardiac development was more advanced at hatch in 18{degrees}C fish. Yet, warmer incubated fish had diminished movement and increased oxygen consumption at 20 days post-hatch, demonstrating long-term disruptions of increased temperature in the embryonic environment. Overall, elevations in rearing temperature may cause metabolic dysfunction and behavioural alterations, potentially impacting the survival of yellow perch.

developmental biology↗

bioRxiv2023

Differences in the transcriptome response in the gills of sea lamprey acutely exposed to 3-trifluoromethyl-4-nitrophenol (TFM), niclosamide or a TFM:niclosamide mixture

Sea lamprey (Petromyzon marinus) control in the Laurentian Great Lakes of North America makes use of two pesticides: 3-trifluoromethyl-4-nitrophenol (TFM) and niclosamide, which are often co-applied. Sea lamprey appear to be vulnerable to these agents resulting from a lack of detoxification responses with evidence suggesting that lampricide mixtures produce a synergistic effect. However, there is a lack of information pertaining to the physiological responses of sea lamprey to niclosamide and TFM:niclosamide mixtures. Here, we characterized the transcriptomic responses of the sea lamprey to TFM, niclosamide, and a TFM:niclosamide (1.5%) mixture in the gill. Along with a control, larval sea lamprey were exposed to each treatment for 6 h, after which gill tissues were extracted for measuring whole-transcriptome responses using RNA sequencing. Differential gene expression patterns were summarized, which included identifying the broad roles of genes and common expression patterns among the treatments. While niclosamide treatment resulted in no differentially expressed genes, TFM- and mixture-treated fish had several differentially expressed genes that were associated with the cell cycle, DNA damage, metabolism, immune function, and detoxification. However, there was no common differential expression among treatments. For the first time, we characterized the transcriptomic response of sea lamprey to niclosamide and a TFM:niclosamide mixture and identified that these agents impact mRNA transcript abundance of genes associated with the cell cycle and cellular death, and immune function, which are likely mediated through mitochondrial dysregulation. These results may help to inform the production of more targeted and effective lampricides in sea lamprey control efforts.

genomics↗

bioRxiv2023

Transcriptomic impacts and potential routes of detoxification in a lampricide-tolerant teleost exposed to TFM and niclosamide

Sea lamprey (Petromyzon marinus) control in the Laurentian Great Lakes of North America often relies on the application of 3-trifluoromethyl-4-nitrophenol (TFM) and niclosamide mixtures to kill larval sea lamprey. Selectivity of TFM against lampreys appears to be due to differential detoxification ability in these jawless fishes compared to bony fishes, particularly teleosts. However, the proximate mechanisms of tolerance to the TFM and niclosamide mixture and the mechanisms of niclosamide toxicity on its own are poorly understood, especially among non-target fishes. Here, we used RNA sequencing to identify specific mRNA transcripts and functional processes that responded to niclosamide or a TFM:niclosamide mixture in bluegill (Lepomis macrochirus). Bluegill were exposed to niclosamide or TFM:niclosamide mixture, along with a time-matched control group, and gill and liver tissues were sampled at 6, 12, and 24 h. We summarized the whole-transcriptome patterns through gene ontology (GO) term enrichment and through differential expression of detoxification genes. The niclosamide treatment resulted in an upregulation of several transcripts associated with detoxification (cyp, ugt, sult, gst), which may help explain the relatively high detoxification capacity in bluegill. Conversely, the TFM:niclosamide mixture resulted in an enrichment of processes related to arrested cell cycle and growth, and cell death alongside a diverse detoxification gene response. Detoxification of both lampricides likely involves the use of phase I and II biotransformation genes. Our findings strongly suggest that the unusually high tolerance of bluegill to lampricides is due to these animals having an inherently high capacity and flexible detoxification response to such compounds.

genomics↗

bioRxiv2021

Variation in the transcriptome response and detoxification gene diversity drives pesticide tolerance in fishes

Pesticides are critical for invasive species management, but often have negative effects on non-target native biota. Tolerance to pesticides should have an evolutionary basis, but this is poorly understood. Invasive sea lamprey (Petromyzon marinus) populations in North America have been controlled with a pesticide lethal to them at lower concentrations than native fishes. We addressed how interspecific variation in gene expression and detoxification gene diversity confer differential pesticide sensitivity in two fish species. We exposed sea lamprey and bluegill (Lepomis macrochirus), a tolerant native species, to TFM, a pesticide commonly used in sea lamprey control, and used whole-transcriptome sequencing of gill and liver to characterize the cellular response. Comparatively, bluegill exhibited a larger number of detoxification genes expressed and a larger number of responsive transcripts overall, which likely contributes to greater tolerance to TFM. Understanding the genetic and physiological basis for pesticide tolerance is crucial for managing invasive species.

genomics↗

bioRxiv2020

Evaluating tank acclimation and trial length for shuttle box temperature preference assays

Thermal preferenda are largely defined by optimal growth temperature for a species and describe the range of temperatures an organism will occupy when given a choice. Assays for thermal preferenda require at least 24 hours, which includes a long acclimation to the tank, limits throughput and thus impacts replication in the study. Three different behavioral assay experimental designs were tested to determine the effect of tank acclimation and trial length (12:12, 0:12, 2:2; hours of tank acclimation: behavioral trial) on the temperature preference of juvenile lake whitefish, using a shuttle box system. Average temperature preferences for the 12:12, 0:12, and 2:2 experimental designs were 16.10 {+/-} 1.07 {degrees}C, 16.02 {+/-} 1.56 {degrees}C, 16.12 {+/-} 1.59{degrees}C respectively, with no significant differences between the experimental designs (p= 0.9337). Ultimately, length of acclimation time and trial length had no significant impact, suggesting that all designs were equally useful for studies of temperature preference.

physiology↗