The widespread use of sunscreens has contaminated aquatic environments with UV filters like oxybenzone (BP-3), which act as endocrine disruptors in aquatic organisms and exhibit enhanced toxicity under UV radiation. This study employed a multi-omics approach integrating responses from genes to whole organisms to investigate UVB-potentiated toxicity of BP-3 in embryos of the marine fish Mugilogobius chulae. Results demonstrated that UVB significantly amplified BP-3 toxicity, reducing LC₅₀ from 5674 μg L⁻¹ to 3653 μg L⁻¹ and impairing key developmental endpoints: spontaneous movement, heart rate, and body length. Notably, BP-3 exhibited moderate binding affinity to ERs of M. chulae, and disrupted estrogen signaling, concurrently driving energy dysregulation via the PI3K/Akt-TOR-FoxO signaling axis under combined exposure. Specifically, PI3K/Akt downregulation reduced energy supply, triggering lipid accumulation; indeed, TOR upregulation exacerbated metabolic burden through abnormal reprogramming. The suppression of autophagy genes hindered the clearance of lipid droplets and organelles, fueling metabolic dysfunction and oxidative stress. ROS accumulation, along with neural disruptions like elevated AChE activity, compromised neural function, ultimately exhibited a decrease in swimming distance, speed, and activity duration. These findings established that UVB and BP-3 co-exposure drove metabolic dysregulation, oxidative damage, and neurotoxicity-highlighting the growing ecotoxicological risks of UV filters in aquatic ecosystems under climate-driven UV intensification.

Reliable normalization is essential for accurate quantitative real-time PCR (qRT-PCR) analysis, yet suitable reference genes have not been systematically evaluated in Mugilogobius chulae, an emerging marine experimental fish used in physiological and environmental research. In this study, 17 candidate reference genes were evaluated in five tissues (brain, gill, gonad, intestine, and liver) of sexually mature male and female M. chulae under solvent control (DMSO), bisphenol A (BPA), cadmium (Cd), and sulfamethazine (SMX) treatment conditions. Gene-expression stability was assessed using the comparative ΔCt method, NormFinder, geNorm, BestKeeper, and the integrated RefFinder ranking. The results showed that reference-gene stability was strongly tissue-specific and analysis-dependent. The integrated RefFinder analysis identified eif3h, rpl7, rps4x, stau1, and ef1y as the most stable genes in the pooled dataset, whereas ube2, hprt1l, and aldob were the least stable. geNorm analysis indicated that two reference genes were sufficient for brain, gill, intestine, and liver, whereas four were required for the gonad and six for cross-tissue comparisons. These findings provide the first systematic basis for reference-gene selection in M. chulae and establish an important methodological foundation for future qRT-PCR studies in this species, particularly in research on endocrine disruption, reproductive physiology, and marine ecotoxicology.

The Mugilogobius myxodermus is an endemic freshwater fish in china. Herein, we sequenced and assembled the first complete mitogenome of M. myxodermus. The total length of the mitogenome is 16,495 bp, containing 13 protein-coding genes, two ribosomal RNAs (rRNA), two non-coding regions (control region and origin of light-strand replication), and 22 transfer RNAs (tRNA). The overall base composition of M. myxodermus is 26.76% T, 28.97% C, 27.81% A, and 16.45% G, respectively. A phylogenetic tree showed that M. myxodermus clustered closest to M. abei. The complete mitogenome of M. myxodermus provides a resource for studies on biogeography and evolution of this gobiid fish.