Newswise \u2014 By identifying and characterizing three key autophagy genes and tracking their responses under environmental stress, the study could help improve fish health management and support sustainable aquaculture.<\/p>\n
Human activities and climate deterioration are increasingly altering aquatic ecosystems, leading to frequent disease outbreaks and heavy economic losses in fish farming.\u00a0Takifugu fasciatus\u00a0is prized for its high nutritional value and medicinal compounds, including tetrodotoxin and collagen. However, the species is highly sensitive to copper contamination and cold stress. Copper concentrations in summer waters can reach levels harmful to growth and survival, while temperatures below 16 \u00b0C suppress feeding and can cause mass mortality. Autophagy is a conserved cellular process that allows cells to recycle damaged components and maintain internal balance under stress. A specialized form\u2014mitochondrial autophagy\u2014targets dysfunctional mitochondria, preventing cellular damage. Three genes,\u00a0lc3,\u00a0beclin-1, and\u00a0p62, serve as core markers of this process, yet their roles in environmental stress responses in T. fasciatus remained largely unexplored.<\/p>\n
A\u00a0study\u00a0(DOI: 10.48130\/animadv-0025-0033)<\/a><\/strong>\u00a0published in\u00a0Animal Advances<\/a><\/strong>\u00a0on 09 January 2026\u00a0by Tao Wang\u2019s team, Nanjing Normal University, elucidates the molecular basis of mitochondrial autophagy in\u00a0Takifugu fasciatus\u00a0under copper and low-temperature stress, providing critical insights for understanding stress adaptation mechanisms and developing strategies to enhance resilience in aquaculture species.<\/p>\n In this study, a combination of molecular cloning, bioinformatic analysis, phylogenetic comparison, quantitative gene expression assays, and protein immunoassays was employed to systematically investigate the characteristics and stress responses of three mitochondrial autophagy\u2013related genes (lc3,\u00a0beclin-1, and\u00a0p62) in Takifugu fasciatus. First, full-length cDNAs were cloned and subjected to sequence analysis to determine molecular weight, amino acid length, isoelectric point, subcellular localization, conserved motifs, and chromosomal distribution. The results showed that\u00a0LC3,\u00a0Beclin-1,\u00a0and\u00a0p62\u00a0proteins had relative molecular weights of 14.72, 51.23, and 45.49 kDa, respectively, with lengths ranging from 125 to 447 amino acids and predicted cytoplasmic localization. Conserved motif analysis revealed that\u00a0LC3\u00a0contained two core motifs, whereas\u00a0Beclin-1\u00a0and\u00a0p62\u00a0harbored multiple conserved domains, and chromosomal mapping demonstrated that the three genes were distributed on different chromosomes, suggesting distinct genomic roles. Phylogenetic analysis using MEGAX and the neighbor-joining method, together with cross-species sequence alignment, showed that all three proteins were highly conserved among teleosts, exhibiting up to 99\u2013100% similarity with Takifugu rubripes and moderate to high homology with mammals and amphibians. Next, qRT-PCR was applied to assess tissue-specific expression patterns, revealing ubiquitous expression of all three genes, with particularly high levels in the liver;\u00a0lc3\u00a0was also strongly expressed in the brain, while\u00a0beclin-1\u00a0showed elevated expression in the liver, heart, and intestine, and\u00a0p62\u00a0was most abundant in the liver. Finally, qRT-PCR and protein immunoassays were used to evaluate hepatic responses under copper (Cu\u00b2\u207a) exposure and low-temperature stress. At the transcriptional level, Cu\u00b2\u207a and cold stress significantly induced\u00a0lc3,\u00a0beclin-1, and\u00a0p62\u00a0expression, with\u00a0beclin-1\u00a0showing the greatest sensitivity. At the protein level, LC3 and Beclin-1 were markedly upregulated under stress, whereas p62 protein levels decreased, indicating active autophagic flux. Collectively, these methodologically integrated results demonstrate that copper and low-temperature stress robustly activate mitochondrial autophagy in the liver of\u00a0T. fasciatus.<\/p>\n The findings provide a molecular framework for understanding how fish respond to environmental stress at the cellular level. Identifying\u00a0beclin-1\u00a0as a particularly sensitive stress marker opens opportunities for developing early diagnostic indicators of environmental stress in aquaculture systems. In the long term, these autophagy-related genes could serve as molecular markers in selective breeding programs aimed at producing more stress-resilient fish strains.<\/p>\n ###<\/p>\n References<\/p>\n DOI<\/strong><\/p>\n 10.48130\/animadv-0025-0033<\/a><\/p>\n Original Source URL<\/strong><\/p>\n https:\/\/doi.org\/10.48130\/animadv-0025-0033<\/a><\/p>\n Funding information<\/strong><\/p>\n This work was supported by the National Natural Science Foundation of China (No. 32473131), the ‘JBGS’ Project of Seed Industry Revitalization in Jiangsu Province [JBGS(2021)034], Jiangsu Agriculture Science and Technology Innovation Fund [CX(22)2029], Jiangsu Province ‘333 High-level Talents Cultivating Project’.<\/p>\n About\u00a0Animal Advances<\/a><\/strong><\/p>\n