Rainbow trout (Oncorhynchus mykiss) is a globally cultured cold-water salmonid, yet triploid larvae often develop spinal ventral lordosis and conjoined twin malformations with unclear molecular mechanisms. Here, RNA-seq of 15 dph normal (N), spinal-deformed (SD) and conjoined (CT) triploid larvae yielded 54.13 Gb of valid data, identifying 4292, 3601 and 2699 DEGs for SD vs. N, CT vs. SD and CT vs. N groups, respectively. Five shared disrupted cascades (cell adhesion, neuroactive ligand-receptor interaction, phagosome, cytokine-receptor interaction, and PI3K-Akt signaling) were identified, while potential calcium/MAPK and steroid-biosynthesis-related pathways were predominantly perturbed in SD and CT larvae, respectively. Filtered PPI sub-networks displayed distinct predicted topological phenotype-associated candidate transcripts, with coagulation and complement transcripts forming core hubs in SD larvae and steroid-related transcripts showing weak connectivity in CT groups. Three discriminative transcripts with inverse expression patterns were screened. This study reveals conserved and phenotype-specific transcriptional phenotype-associated candidate transcripts of the two malformations and provides candidate phenotype-associated transcripts for subsequent functional verification of larval malformations. It should be noted that all transcriptomic data originate from whole-larval homogenates; expression signatures of conjoined-twin larvae may be confounded by altered tissue-type proportions rather than malformation-exclusive regulatory mechanisms.

Marine biofouling by sessile invertebrates such as Diadumene lineata poses a persistent threat to marine infrastructure, and antifouling agents are critical for mitigating this issue, yet their molecular mechanisms of action on fouling cnidarians remain poorly understood. In this study, acute toxicity tests and 24 h attachment inhibition assays were conducted, followed by transcriptomic sequencing of pedal disc tissue from D. lineata exposed to N-oleyl-1,3-propanediamine. The 96 h-LC₅₀ of the agent was determined to be 38.66 mg/L, and exposure to 70 mg/L agent achieved complete 24 h attachment inhibition. Transcriptomic analysis identified extensive transcriptional perturbations across four core physiological systems: metabolic reprogramming via activated PPAR signaling, immune dysregulation characterized by impaired antigen processing and DAMP-mediated inflammation, disrupted post-transcriptional regulation and proteostasis, and compromised axon regeneration with decoupled damage sensing and repair. Collectively, these interconnected disruptions synergistically impaired the structural integrity, energy supply, and stress adaptation capacity of pedal disc cells, ultimately leading to adhesion inhibition in D. lineata. This study clarifies the multi-pathway toxic mechanism of antifouling agents in fouling sea anemones, providing a foundational molecular framework for future research.

This study evaluated the acute toxicity and attachment inhibition effects of five novel nonoxidizing circulating water treatment agents on key marine fouling organisms, namely Crassostrea gigas eyed larvae and Mytilus edulis spat, aiming to screen ecofriendly and efficient antifouling agents for nuclear power cooling systems. A 96 h semistatic acute toxicity assay was adopted combined with byssal secretion parameter determination, and data were analyzed using probit analysis, independent samples t-tests, and ANOVA. The test organisms, C. gigas eyed larvae (shell length ≈ 200 μm, actively swimming) and M. edulis spat (shell length 1–2 cm, intact shell, healthy), were acclimated under controlled conditions (25 ± 0.5 °C, salinity 20 ± 1, DO ≥ 6 mg/L, 12L:12D photoperiod). Five agents containing different alkylamine and polyoxyethylene ether components were tested at gradient concentrations (0–1.92 mg/L for C. gigas larvae and 0–18 mg/L for M. edulis spat), with 50% test solution renewal every 24 h. The measured indicators included 96 h LC₅₀, safe concentrations, attachment inhibition rates, and M. edulis byssal secretion parameters (number, total length, diameter of byssal threads, and shedding frequency). All agents showed significant dose dependent toxicity ( P < 0.05). For C. gigas larvae, the toxicity was ranked as Agent 4 > Agent 2 > Agent 5 > Agent 3 > Agent 1, with 96 h LC₅₀ ranging from 0.13 to 1.00 mg/L, while for M. edulis spat, the toxicity was ranked as Agent 3 > Agent 2 > Agent 5 > Agent 1 > Agent 4, with 96 h LC₅₀ ranging from 7.65 to 9.74 mg/L. Agent 3 significantly reduced the number, length, and diameter of M. edulis byssal threads and increased shedding frequency ( P < 0.05) through a dual inhibition mechanism by interfering with byssal protein synthesis and substrate adhesion. Overall, Agent 3 exhibited balanced antifouling efficacy and environmental safety, and is recommended at 15 mg/L for biofouling control in nuclear power cooling systems to avoid the toxic byproducts of traditional oxidizing agents.

Marine biofouling remains a persistent challenge to maritime industries and marine ecosystems worldwide. In this study, we systematically evaluated the acute toxicity, settlement inhibitory efficacy, and underlying molecular mechanisms of an N-oleyl-1,3-propanediamine-based antifouling agent using pediveliger larvae of the Pacific oyster Crassostrea gigas. The 96 h-LC50 of the agent was determined to be 0.81 mg/L, and exposure to 1.68 mg/L achieved complete larval settlement inhibition without inducing significant acute toxicity. Transcriptomic analysis identified 791 differentially expressed genes, dominated by downregulated genes associated with ribosomal function, translation, cell adhesion, and cytoskeletal organization. The agent exerts its inhibitory effect primarily through the global suppression of protein synthesis, disruption of cell-substrate adhesion and cytoskeletal integrity, and induction of proteotoxic stress responses. These findings reveal a multi-pathway molecular mechanism underlying antifouling agent-induced settlement inhibition in oyster larvae and provide key molecular biomarkers to support the development of eco-friendly antifouling technologies.

The kinetic parameters of No.0 fuel oil and Pinghu crude oil water-accommodated fractions (WAFs) during accumulation and elimination in Exopalaemon carinicauda were quantified using a semi-static two-compartment kinetic model. The accumulation phase data were analyzed via nonlinear regression to obtain kinetic parameters, yielding critical values including the uptake rate constant (k₁), elimination rate constant (k₂), bioconcentration factor (BCF), equilibrium body burden (C_Amax), and biological half-life (B_1/2). Modeling results demonstrated distinct kinetic parameters for the two oils. For No.0 fuel oil, the average values were k₁ = 5.21; k₂ = 0.1105; BCF = 48.98; C_Amax = 2.95 mg/kg; and B_1/2 = 6.40 days. For Pinghu crude oil, the averages were k₁ = 10.25; k₂ = 0.1044; BCF = 98.15; C_Amax = 8.48 mg/kg; and B_1/2 = 6.64 days. The uptake rate constant (k₁) and BCF generally decreased with increasing petroleum hydrocarbon exposure concentrations in ambient seawater, while the elimination rate constant (k₂) remained relatively constant across different concentrations. C_Amax increased proportionally with the petroleum hydrocarbon exposure concentration. Goodness-of-fit tests confirmed that the petroleum hydrocarbon concentrations in the experimental data were well described by the semi-static two-compartment model. Throughout the testing period, the concentration of No.0 fuel oil in Exopalaemon carinicauda remained lower than that of Pinghu crude oil.

This study combined acute toxicity assays, phenotypic quantification, and transcriptomic profiling to systematically investigate the inhibitory effects and molecular regulatory mechanisms of a novel alkylamine-based antifouling agent on survival, byssus secretion, and attachment behavior of juvenile Mytilus edulis. The 96 h-LC50 of the agent to juvenile M. edulis was 8.84 mg/L, and 10 mg/L of the agent completely inhibited mussel attachment within 24 h, significantly reducing byssal thread number, length, and diameter while increasing detachment frequency, resulting in irreversible attachment failure. Transcriptomic analysis identified 2746 differentially expressed genes, which were mainly enriched in pathways including signal transduction, immune defense, stress response, cytoskeleton organization, and protein binding. KEGG and GSEA enrichment revealed that the antifouling agent activated the MAPK stress signaling pathway, disturbed transcriptional regulation, and impaired intracellular homeostasis and cytoskeletal stability, thereby synergistically suppressing the expression of key byssal protein genes including mfp-1 and mfp-3 and ultimately blocking byssus synthesis and adhesion. This study clarifies the multi-pathway molecular mechanism underlying antifouling agent-induced attachment inhibition in M. edulis, and provides core molecular targets and theoretical support for developing efficient, low-toxicity, and eco-friendly marine antifouling technologies.