Browsing by Author "Molina, Alfredo"

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    Gills de novo assembly reveals oxidative stress, unfolded protein, and immune response on red cusk-eel ( Genypterus chilensis ) under thermal stress
    (2024) Dettleff, Phillip; Toloza, Carla; Fuentes, Marcia; Aedo, Jorge; Zuloaga, Rodrigo; Estrada, Juan Manuel; Molina, Alfredo; Valdes, Juan Antonio
    The heat waves on the South Pacific coast could lead to thermal stress in native fish. The red cusk-eel ( Genypterus chilensis ) is relevant for Chilean artisanal fisheries and aquaculture diversification. This study examined the effect of high-temperature stress in the gills of G. chilensis in control (14 degrees C) and high-temperature stress (19 degrees C) conditions. High-temperature stress induces a significant increase in gills cortisol levels. Additionally, oxidative damage was observed in gills (protein carbonylation and lipoperoxidation). RNA-seq data was used to build the first transcriptome assembly of gills in this species (23,656 annotated transcripts). A total of 1138 downregulated and 1531 up-regulated transcripts were observed in response to high-temperature stress in gills. The enrichment analysis showed immune response and replication enriched processes (on down-regulated transcripts), and processes related to the folding of proteins, endoplasmic reticulum, and transporter activity (on upregulated transcripts). The present study showed how gills could be affected by high-temperature stress.
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    High-Temperature Stress Effect on the Red Cusk-Eel (Geypterus chilensis) Liver: Transcriptional Modulation and Oxidative Stress Damage
    (MDPI, 2022) Dettleff, Phillip; Zuloaga, Rodrigo; Fuentes, Marcia; Gonzalez, Pamela; Aedo, Jorge; Manuel Estrada, Juan; Molina, Alfredo; Antonio Valdes, Juan
    Simple Summary The red cusk-eel (Genypterus chilensis) is a native Chilean species important for aquaculture diversification in Chile. The effect of high-temperature stress on the liver, a key organ for fish metabolism, is unknown. In this study we determined for the first time the effects of high-temperature stress on the liver of red cusk-eel. The results showed that high-temperature stress increased hepatic enzyme activity in the plasma of stressed fish. Additionally, this stressor generated oxidative damage in liver, and generated a transcriptional response with 1239 down-regulated and 1339 up-regulated transcripts associated with several processes, including unfolded protein response, heat shock response and oxidative stress, among others. Together, these results indicate that high-temperature stress generates a relevant impact on liver, with should be considered for the aquaculture and fisheries industry of this species under a climate change scenario. Environmental stressors, such as temperature, are relevant factors that could generate a negative effect on several tissues in fish. A key fish species for Chilean aquaculture diversification is the red cusk-eel (Genypterus chilensis), a native fish for which knowledge on environmental stressors effects is limited. This study evaluated the effects of high-temperature stress on the liver of red cusk-eel in control (14 degrees C) and high-temperature (19 degrees C) groups using multiple approaches: determination of plasmatic hepatic enzymes (ALT, AST, and AP), oxidative damage evaluation (AP sites, lipid peroxidation, and carbonylated proteins), and RNA-seq analysis. High-temperature stress generated a significant increase in hepatic enzyme activity in plasma. In the liver, a transcriptional regulation was observed, with 1239 down-regulated and 1339 up-regulated transcripts. Additionally, high-temperature stress generated oxidative stress in the liver, with oxidative damage and transcriptional modulation of the antioxidant response. Furthermore, an unfolded protein response was observed, with several pathways enriched, as well as a heat shock response, with several heat shock proteins up regulated, suggesting candidate biomarkers (i.e., serpinh1) for thermal stress evaluation in this species. The present study shows that high-temperature stress generated a major effect on the liver of red cusk-eel, knowledge to consider for the aquaculture and fisheries of this species.
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    High-Temperature Stress Induces Autophagy in Rainbow Trout Skeletal Muscle
    (2023) Molina, Alfredo; Dettleff, Phillip; Valenzuela-Munoz, Valentina; Gallardo-Escarate, Cristian; Valdes, Juan Antonio
    Ectothermic animals, such as teleosts, have increasingly been exposed to stressful high-temperature events due to global warming. Currently, the effects of thermal stress on skeletal muscle, a key tissue for fish growth, are unknown. This study examined the impact of high-temperature stress on the skeletal muscle transcriptome of rainbow trout (Oncorhynchus mykiss) in control (15 & DEG;C) and high-temperature (20 & DEG;C) conditions. Additionally, we examined the plasmatic levels of cortisol, glucose, and creatine kinase activity, and examined oxidative damage and autophagy activation in skeletal muscle. High-temperature stress induced significant increases in cortisol and glucose plasmatic levels. Nevertheless, no changes were observed in creatine kinase activity in plasma and skeletal muscle oxidation. Skeletal muscle RNA was isolated and sequenced using the HiSeq Illumina platform. A total of 383,796,290 reads were mapped onto the reference rainbow trout genome. The transcriptomic analysis showed that 293 genes were upregulated in the high-temperature group, mainly associated with autophagosome assembly, amino acid transport, and the glutamine metabolic process. On the other hand, 119 genes were downregulated in the high-temperature group, mainly associated with digestion, proteolysis, and the muscle contraction process. In addition, RT-qPCR of differentially expressed representative genes and Western blot analysis of LC3-II/LC3-I levels confirmed skeletal muscle autophagy induced by high temperature. This study sheds light on intriguing facets of the adaptive response of rainbow trout skeletal muscle to high-temperature stress and provides significant insights into the physiology of autophagy in teleosts.
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    Thermal stress generate oxidative damage in black cusk-eel embryos (Genypterus maculatus)
    (WILEY, 2021) Dettleff, Phillip; Zuloaga, Rodrigo; Godoy, Camila; Palomino, Jaime; Molina, Alfredo; Antonio Valdes, Juan
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    Trends in obesity and diabetes prevalence in a Chilean urban population: 1993-2001
    (2008) Cuevas, Ada; Molina, Alfredo; Rigotti Rivera, Attilio; Miquel P., Juan Francisco; Marshall Rivera, Guillermo; Reyes, Soledad; Nervi, Flavio