Comparative Biochemistry and Physiology C-toxicology & Pharmacology最新文献

The effects of plastic pollution on marine organisms is of growing concern. The hydrophobic surface of plastics adsorbs organic contaminants and can alter the rate of chemical uptake in fishes. Per-fluorinated organic chemicals such as Perfluorooctanoic acid (PFOA) are highly hydrophobic toxic chemicals that adsorb to hydrophobic surfaces. We hypothesized that the presence of nano-sized plastic particles adsorbs PFOA and alter both the physical-chemical properties of the plastics and also enhance PFOA uptake into organisms. Using radiolabelled ¹⁴C-PFOA, we measured direct unidirectional uptake of PFOA in juvenile Pacific Oysters (Magallana gigas) at different (0.025, 0.50, and 0.100 mg/L) concentrations, for different exposure periods (1, 2, 4, and 6 h) and investigated whether varying concentrations (0.1, 0.5, 1 mg/L) of either 500 nm or 20 nm polystyrene nanoparticles (PS-NPs) differentially altered the uptake rate of PFOA. Our results demonstrate that PFOA adsorbs to the surface of PS-NPs, altering PS-NP behaviour in solution and significantly increases the rate of uptake of PFOA in exposed Pacific oysters. PFOA uptake at 0.1 mg/L was increased 2.3-fold in the presence of 1 mg/L 500 nm PS-NP and 3.2-fold in the presence of 1 mg/L 20 nm PS-NP. In a separate study to examine if PS NPs potentiate the biochemical response to PFOA, both 500 and 20 nm PS-NP at 100 mg/L increased the 1 mg/L PFOA-induced oxidative stress by 2.5-fold and 3-fold respectively. These findings demonstrate that nanoplastics as co-contaminants in marine systems are able to adsorb PFOA and significantly potentiate its uptake and toxicity.

Due to its high concentration and persistence, microplastic (MP) pollution is a major threat to marine environments. Expanded polystyrene (EPS) particles are the most abundant MP type in Asian regions, including the Korean coastal region. Although many previous studies have reported the toxicity of MPs to marine biota, the toxicity of environmentally relevant MPs to coastal organisms is not well understood. Thus, we investigated the toxicity of EPS on the growth and energy metabolism of the juvenile marine isopods, Ligia cinerascens, obtained from a population that has been exposed to EPS through multiple generations. After 14 and 21 days of dietary EPS exposure, body weight and molting of L. cinerascens were unaffected. However, the energy reserves (carbohydrates, proteins, and lipids) were significantly reduced, resulting in a decrease in the total energy budget (E_a) by dietary EPS exposure. The transcriptional modulation patterns of genes related to energy metabolism suggested that dietary EPS exposure may increase the digestion of non-carbohydrate sources, such as proteins and lipids, to compensate for increased energy expenditure. Our findings suggest that dietary EPS exposure, although no toxic at the individual level, can reduce the energy status of juvenile marine isopods, which provides useful information on the toxic effects of environmentally relevant MPs to coastal ecosystem.

Cathelicidin is a family of antimicrobial peptides in vertebrates that plays an important role in resistance and immunization against pathogenic microorganisms. In the present study, the full-length cDNA sequences of four novel cathelicidins (cathelicidin-1 to cathelicidin-4) in the tiger frog Hoplobatrachus rugulosus, encoding 153, 188, 132, and 160 amino acids, respectively, were firstly cloned by rapid amplification of the cDNA ends (RACE) technique. Sequence comparison and phylogenetic tree analysis indicated that the structures of the four cathelicidins are highly diverse. Afterwards, the tissue distribution profiles and antimicrobial patterns of cathelicidins in H. rugulosus were determined by real-time PCR. The four cathelicidins showed tissue-specific distribution patterns in the healthy frogs, and the transcriptional levels of cathelicidins exhibited a tissue- and time-dependency profile in the frogs challenged with pathogenic bacteria Aeromonas hydrophila for 72 h. The synthetic peptides of cathelicidin-1 and cathelicidin-2 exhibited broad-spectrum in vitro antimicrobial activity, and cathelicidins exerted antimicrobial activities through excessive induction of reactive oxygen species and direct disruption of the microbial membrane structure. In addition, the intraperitoneal injection of cathelicidin proteins significantly increased the marine medaka Oryzias melastigma resistance to bacterial challenges. The existence of multiple cathelicidins, their distinct tissue distribution patterns, and the inducible expression profiles suggest a sophisticated, highly redundant, and multilevel network of antimicrobial defense mechanisms in tiger frogs. This study provides evidence that cathelicidins have antimicrobial and immunomodulatory activities, and cathelicidins derived from H. rugulosus have potential therapeutic applications against pathogenic infections in aquaculture.

Perfluorooctanesulfonic acid (PFOS) and sodium nitrite may have complex adverse effects on aquatic animals. This study assessed the interactive effects of PFOS and sodium nitrite on Chinese mitten crab (Eriocheir sinensis). A 2 × 3 factorial experiment with 0, 0.1, and 5 mg/L PFOS and 0, 3.50 mg/L sodium nitrite evaluated impacts on growth, behavior, oxygen consumption, health, energy metabolism, and hepatopancreas transcriptome. PFOS <0.1 mg/L with 3.50 mg/L nitrite significantly decreased PFOS accumulation in the hepatopancreas and improved feeding rates and hepatopancreas structure (P < 0.05). Under 5 mg/L PFOS and nitrite, survival, weight gain, hepatosomatic index, and feeding rate significantly decreased (P < 0.05). PFOS (0.1 mg/L) with nitrite significantly prolonged righting response time and increased locomotion speed (P < 0.05). PFOS (5 mg/L) significantly decreased serum triglyceride and lactate levels, while PFOS and nitrite decreased glucose, triglyceride, and glycogen levels and increased lactate in hepatopancreas (P < 0.05). Transcriptomic analysis indicated that PFOS affects p53 signaling, cell cycle and neurotransmission pathways, with notable changes in cell proliferation genes (pcna, ccna, cdk1, cdk2, rbx1) primarily downregulated by PFOS. Overall, PFOS disrupts neurotransmitter regulation and causes hepatopancreatic damage, while nitrite can reduce the toxicity of PFOS by decreasing its hepatopancreas accumulation. However, high levels of PFOS combined with sodium nitrite exacerbate toxicity, emphasizing the need for comprehensive assessment of environmental pollutant interactions.

Cyantraniliprole (CYA), widely recognized as a highly effective solution, is widely used in pest management. It has been broadly utilized to manage diverse pests, among which Aphis gossypii Glover (Hemiptera: Aphididae) is a prominent agricultural pest that leads to significant crop damage worldwide. Studies suggest that the sublethal effect of insecticides might contribute to the resurgence of A. gossypii. Therefore, in this study, A. gossypii were exposed to sublethal doses of CYA (LC₁₅ and LC₃₀ values of 1.43 and 2.93 mg/L, respectively) for 48 h then employed life table parameters and RT-qPCR were used to estimate the sublethal and cross-generational impacts. Treatments with sublethal doses of CYA notably reduced the survival and reproduction of the F₀A. gossypii and CYA at LC₃₀ significantly increased the fecundity and population growth parameters (R₀, r, λ, and GRR) of F₁ and reduced in the pre-adult stage. Furthermore, gene expression analysis indicated a significant downregulation of juvenile hormone-binding protein (JHBP) in F₀. Conversely, the F₁ generation exhibited an upregulation of vitellogenin (Vg), insulin receptor substrate 1 (InS1), ecdysone receptor (EcR), and ultraspiracle protein (USP). The funding not only enhance the comprehension of the sublethal effects of CYA on A. gossypii but also provide valuable guidance for the effective utilization of insecticides in managing the pest.

Zearalenone (ZEA), a common mycotoxin, poses significant environmental and health risks. While its toxicological effects are well-studied, its impact on regeneration remains unclear. This study explored ZEA's effects on zebrafish (Danio rerio) larvae, focusing on developmental toxicity, immunotoxicity, and tissue regeneration. Embryos were exposed to 0, 0.5, 1, and 1.5 μM ZEA from 6 to 72 h post-fertilization (hpf). Although hatching and survival rates remained unaffected, malformations, including body axis bending and pericardial edema, increased dose-dependently, with 4.44 % abnormalities observed at 1.5 μM (p = 0.01). Heart rates also declined significantly at 1.5 μM (75.40 vs. 72.53 beats/30s, p = 0.0054). Immunotoxicity was assessed using Tg(mpx: eGFP) zebrafish to monitor neutrophil responses post-injury. ZEA exposure led to increased neutrophil counts (229.87 vs. 330.80, p < 0.0001) and chemotaxis (21.15 % vs. 34.57 %, p < 0.0001). RNA sequencing of 0 and 1.5 μM groups revealed disrupted redox balance and oxygen transport, with down-regulation of hbae1, hbbe2, and hbae3 and up-regulation of hif1a, indicating hypoxia involvement. Elevated reactive oxygen species (ROS), reduced antioxidant enzyme activity, and increased apoptosis were also observed. Tail fin regeneration assays showed delayed regeneration at 1 and 1.5 μM ZEA, linked to impaired immune function and oxidative stress. These findings highlight ZEA's adverse effects on developmental and regenerative processes, underscoring its environmental and health implications and the need for further research.

The toxic effects of long-term exposure to low doses of chlorpyrifos (CPF) on Eriocheir sinensis were evaluated using acute toxicity tests, transcriptome analyses, and metabolome profiling. Four groups (three replicates per group, 60 crabs)-control (no CPF exposure), high exposure (0.12 mg/L CPF), medium exposure (0.036 mg/L), and low exposure (0.012 mg/L)-were subjected to CPF for 21 days. Tissue damage, antioxidant enzyme activity, transcriptional changes, and metabolic alterations in E. sinensis were analyzed. The results demonstrated that CPF disrupted the regulatory networks of transcription and metabolism in crabs under the experimental concentration conditions, with the severity of effects increasing as the duration of exposure lengthened despite the crabs' efforts to activate key defense mechanisms, such as upregulation of cholinesterase 1-like gene expression, to counteract organophosphorus toxicity and adapt to CPF presence in their environment. Even at low concentrations (0.012 mg/L), neurobehavioral development and the antioxidant kinase system in crabs were impaired, leading to hepatopancreatic tissue lesions that negatively affect their growth and survival rates. Additionally, E. sinensis accumulates significant levels of CPF, which may pose food safety concerns when humans consume them. Therefore, ensuring the rational use of CPF requires maintaining appropriate water concentrations to minimize direct harm to aquatic organisms and indirect impacts on food safety associated with this pesticide.

Perfluorooctanoic acid (PFOA) and its substitute, hexafluoropropylene oxide dimer acid (GenX), are widely used perfluorinated compounds (PFCs) that pose significant risks to marine ecosystems. However, the specific impacts of these contaminants on marine invertebrates, particularly echinoderms, remain poorly understood. Strongylocentrotus intermedius, a globally significant benthic aquacultural species, may be potentially affected by PFCs. This study aimed to assess the reproductive toxicity of PFOA and GenX in S. intermedius. After exposing S. intermedius to either PFOA or GenX for 7 or 14 days, it was observed that even at environmentally relevant concentrations (2 μg/L), both compounds inhibited normal growth and gonadal development in S. intermedius, with effects becoming more pronounced over time. Further analysis revealed that prolonged exposure to PFCs resulted in a significant reduction in energy reserves (glycogen, lipids, and proteins) and caused abnormal changes in metabolic enzyme activities, with PFOA exhibiting more pronounced effects compared to GenX. At the genetic level, the expression of genes related to gonadal development initially increased and then decreased as the concentrations of the compounds rose. Additionally, integrated biomarker response analysis indicated that PFOA had greater reproductive toxicity than GenX, in terms of both concentration and exposure duration. These results provided a preliminary evaluation of the impact of PFCs on marine invertebrates, offering a foundation for further research into their ecological risks and contributing to the development of more comprehensive environmental risk assessments for these contaminants.

Perfluorononanoic acid (PFNA) is a perfluoroalkyl acid containing nine carbon chains, with an additional carbon‑fluorine bond that makes it more stable and toxic. Studies have shown that PFNA can harm the reproductive, immune, and nervous systems, as well as many organs, which can increase the risk of cancer. In this study, zebrafish embryos were treated with 0 and 100 μM PFNA for 72 and 96 hpf, and their angiogenesis and haematopoiesis were observed under laser confocal microscopy using Tg (fli1:EGFP) and Tg (gata1:DsRed) transgenic zebrafish. The data showed that PFNA exposure decreased heart rate and slowed blood flow in zebrafish. PFNA was found to inhibit erythropoiesis by O-dianisidine staining. RNA-seq analysis was used to compare gene expression changes in zebrafish from control and 100 μM PFNA-exposed groups at 72 hpf. KEGG results showed significant enrichment of PPAR signaling pathway, fatty acid metabolism, steroid biosynthesis and apoptosis. The RNA-seq results were validated by real-time fluorescence quantitative PCR (RT-qPCR). Oil red O staining and Filipin staining showed increased lipid accumulation after PFNA exposure, and TUNEL staining showed that PFNA exposure led to apoptosis. In conclusion, exposure to PFNA may cause toxic effects in zebrafish by affecting cardiovascular development, causing lipid accumulation and promoting apoptosis.

Numerous environmental pollutants exhibit ototoxicity and cause damage to the lateral line structures in fish, including the neuromast and its hair cells. The lateral line is used to detect hydrodynamic changes and is thought to play a significant role in aggressive interactions. Fighting behaviors in fish are crucial for establishing social hierarchy and obtaining limited resources. In this study, we ablated the function of hair cells using a commonly used ototoxin, neomycin, to evaluate the impact of this ototoxic pollutant on fighting behavior through damaging the lateral line. Our results showed that the number of wins and the duration of dyadic fight behavior decreased in zebrafish with lateral line ablation. These zebrafish also exhibited increased anxiety and biting frequencies. On the other hand, social preferences and fitness were not affected in lateral line-ablated zebrafish. In conclusion, the lateral line mechanosensory system is crucial for fish to gather sufficient information and make correct decisions during conflicts and fighting behaviors. Impairment of hair cell function can affect aggressive behaviors and decision-making in fish, subtly altering their behavioral patterns and leading to significant impacts on the aquatic ecosystem.