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Nanomaterials have attracted much attention in the biomedical field. Black phosphorus quantum dots (BPQDs) have shown great potential in biomedical applications, but their potential risks to biosafety and environmental stability have not been fully evaluated. In the present study, zebrafish (Danio rerio) embryos were exposed to 0, 2.5, 5 and 10 mg/L BPQDs from 2 to 144 h post-fertilization (hpf) to explore developmental toxicity. The results showed that exposure to BPQDs for 96 h induced developmental malformations (tail deformation, yolk sac edema, pericardial edema, and spinal curvature) in zebrafish embryos. ROS and antioxidant enzyme activities (CAT, SOD, MDA and T-AOC) were substantially altered and the acetylcholinesterase (AChE) enzyme activity was significantly decreased in the BPQDs exposed groups. Locomotor behavior was inhibited after BPQDs exposure for 144 h in zebrafish larvae. A significant increase in 8-OHdG content indicates DNA oxidative damage in embryos. In addition, obvious apoptotic fluorescence signals were detected in the brain, spine, yolk sac and heart. At the molecular level, the mRNA transcript levels of key genes related to skeletal development (igf1, gh, MyoD and LOX), neurodevelopment (gfap, pomca, bdnf and Mbpa), cardiovascular development (Myh6, Nkx2.5, Myl7, Tbx2b, Tbx5 and Gata4) and apoptosis (p53, Bax, Bcl-2, apaf1, caspase-3 and caspase-9) were abnormal after BPQDs exposure. In conclusion, BPQDs induced morphological malformations, oxidative stress, locomotor behavior disorders, DNA oxidative damage and apoptosis in zebrafish embryos. This study provides a basis for further study on the toxic effects of BPQDs. [Display omitted] • BPQDs caused developmental toxicity in the zebrafish embryos. • BPQDs induced oxidative stress, oxidative DNA damage and apoptosis in zebrafish embryos. • BPQDs induced developmental neurotoxicity and decreased locomotor behavior. [ABSTRACT FROM AUTHOR]

Abstract Ionic liquids have garnered increasing attention due to their capacity for low vapor pressure, lack of flammability, designability, good stability, and as a asubstitute for conventional organic solvents. However, their toxicity to various organisms has caused growing concern in recent years. Our study aims to evaluate the toxicity of 1-hexadecyl-3-methylimidazolium chloride ([C 16 min]Cl) to human hepatocellular carcinoma (HepG2) cells, including cell viability, genotoxicity, oxidative stress, apoptosis, cell cycle, and apoptosis-related gene expression. Our results with HepG2 cells suggested that [C 16 min]Cl inhibited cellular growth, decreased cell viability, induced DNA damage and apoptosis, inhibited superoxide dismutase, decreased glutathione content, increased cellular malondialdehyde levels as well as altering the cell cycle. Moreover, the induction of [C 16 min]Cl altered the transcription of p53 , Bax and Bcl-2 , which are critical for controlling cell cycles progression and death, which suggests its involvement with cytotoxicity and apoptosis induced by [C 16 min]Cl in HepG2 cells. Taken together, these results revealed that [C 16 min]Cl exerted genotoxicity, oxidative stress and induced apoptosis in HepG2 cells; hence, it is not a healthy solvent. Highlights • [C 16 min]Cl is cytotoxic to HepG2 cells. • [C 16 min]Cl inhibits HepG2 cells growth and decreases their viabilities. • [C 16 min]Cl exerts genotoxicity, oxidative stress and induces apoptosis in HepG2 cells. [ABSTRACT FROM AUTHOR]

Ovary development is a complex process involving numerous genes; the molecular mechanism underlying the ovary development of carp is still unknown. Here we used Illumina HiSeq™ 2500 to explore the transcriptome of undifferentiated gland (PG), juvenile ovary (OJ) and adult ovary (OA) of Yellow River carp ( Cyprinus carpio ). A total of 58,749 unigenes were obtained, comprising 45,707 known genes and 13,042 new genes. We identified differentially-expressed genes (DEGs) during development and characterized the functional properties of DEGs by comparison with the gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes databases. qRT-PCR was used to analyze the expression of 22 DEGs and the results corresponded with those of RNA-Seq. Among DEGs between PG and OJ, some upstream regulators of gonad development were upregulated in PG, such as cyp19a and sox9 , while some oocyte-specific genes were upregulated in OJ, such as nobox, bmp15 and zp2 . Among DEGs between OJ and OA, many oocyte physiological function-related genes were upregulated in OA, such as fem-1 and foxl2 . GO analysis showed a higher number of DEGs from PG–OJ analysis were assigned to reproduction terms. Furthermore, our investigation has also revealed DEGs identified from PG–OJ analysis were enriched in several important functional pathways, such as Fanconi anemia and the notch signal pathway. These data suggested a dynamic shift in gene expression during ovary development, and DEGs between PG and OJ provided crucial candidate gene data for the study of ovarian differentiation. Additionally, a total of 1,776,769 single nucleotide polymorphisms and 157,279 INDEs were revealed from transcriptome data. This result will contribute to knowledge of ovary differentiation of Yellow River carp. [ABSTRACT FROM AUTHOR]

Sox4 belonged to the SoxC subfamily of the Sox family, which play important roles in the development of the vertebrate gonad and nervous system. A Sox4 homologue was cloned from brain of Paramisgurnus dabryanus by using homologous cloning and rapid amplification of cDNA ends (RACE), designated as PdSox4 . The full-length cDNA was 2163bp, containing the 759bp 5'-untranslated region, 267bp 3'-untranslated region and encoding a putative protein of 378 amino acids with a characteristic high mobility group box (HMG-box) DNA-binding domain of 79 amino acids with the specific motif (RPMNAFMVW). Alignment and phylogenetic analyses indicated that PdSox4 shares highly identical sequence with Sox4 homologues from different species. The signal peptide analysis predicted that PdSox4 is a non-secretory protein. The hydropathy profile of PdSox4 protein revealed that this protein is hydrophilic in nature. The expression profiles of PdSox4 in different developmental stages and various adult tissues of sexs were analyzed by quantitative real-time RT-PCR (qRT-PCR) and In situ hybridization (ISH). The results showed that PdSox4 was ubiquitously expressed during embryogenesis and various adult tissues, especially in central nervous system. Tissue distribution analyses revealed that PdSox4 was expression in developing germ cells. Taken together, these preliminary findings suggested that PdSox4 is highly conserved during vertebrate evolution and involved in a wide range of developmental processes including embryogenesis, neurogenesis and gonad development. [ABSTRACT FROM AUTHOR]

Teleost fins can regenerate accurate position-matched structure and function after amputation. However, we still lack systematic transcriptional profiling and methodologies to understand the molecular basis of fin regeneration. After histological analysis, we established a suppression subtraction hybridization library containing 418 distinct sequences expressed differentially during the process of blastema formation and differentiation in caudal fin regeneration. Genome ontology and comparative analysis of differential distribution of our data and the reference zebrafish genome showed notable subcategories, including multi-organism processes, response to stimuli, extracellular matrix, antioxidant activity, and cell junction function. KEGG pathway analysis allowed the effective identification of relevant genes in those pathways involved in tissue morphogenesis and regeneration, including tight junction, cell adhesion molecules, mTOR and Jak-STAT signaling pathway. From relevant function subcategories and signaling pathways, 78 clones were examined for further Southern-blot hybridization. Then, 17 genes were chosen and characterized using semi-quantitative PCR. Then 4 candidate genes were identified, including F11r , Mmp9 , Agr2 and one without a match to any database. After real-time quantitative PCR, the results showed obvious expression changes in different periods of caudal fin regeneration. We can assume that the 4 candidates, likely valuable genes associated with fin regeneration, deserve additional attention. Thus, our study demonstrated how to investigate the transcript profiles with an emphasis on bioinformatics intervention and how to identify potential genes related to fin regeneration processes. The results also provide a foundation or knowledge for further research into genes and molecular mechanisms of fin regeneration. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) are members of humoral immunity and particpate in resisting microbial invasion. In this study, an AMP gene hepcidin was obtained from the oriental loach Misgurnus anguillicaudatus and named Ma-Hep. This Ma-Hep encodes a peptide of 90 amino acids, with a predicted active peptide segment (Ma-sHep) of 25 amino acids at C terminus. Stimulation by a bacterial pathogen Aeromonas hydrophila resulted in significant up-regulation of Ma-Hep transcripts in loach midgut, head kidney, and gill. Ma-Hep and Ma-sHep proteins were expressed in Pichia pastoris and their antibacterial activity was examined. Results showed that Ma-sHep possessed stronger antibacterial activity against various Gram-positive and Gram-negative bacteria, compared to Ma-Hep. Scanning electron microscopy showed that Ma-sHep might kill bacteria by destroying bacterial cell membranes. Moreover, we found that Ma-sHep had an inhibitory effect on blood cell apoptosis induced by A. hydrophila and facilitated the bacterial phagocytosis and clearance in loach. Histopathological analysis indicated Ma-sHep could protect liver and gut of loach from bacterial infection. Ma-sHep has high thermal stability and PH stability, which is conducive to further feed addition. Feed supplemented with Ma-sHep expressing yeast improved the intestinal flora of loach by increasing the dominant bacteria and decreasing the harmful bacteria. Feed supplemented with Ma-sHep expressing yeast also regulated the expression of inflammatory related factors in various tissues of loach and reduced the mortality of loach upon bacterial infection. These findings show that the antibacterial peptide Ma-sHep is involved in the antibacterial defense of loach and can be used as a candidate for new antimicrobial agents in aquaculture. • The Hepcidin from Misgurnus anguillicaudatus was cloned and identified. • Ma-sHep possessed strong antibacterial activity against various bacteria. • Ma-sHep had an inhibitory effect on blood cell apoptosis induced by A. hydrophila. • Ma-sHep could protect loach tissues from bacterial infection. • Feed supplemented with Ma-sHep expressing yeast enhance immune capacity of loach. [ABSTRACT FROM AUTHOR]

Pollution of microplastics (MPs) has become a global environmental issue due to the difficulty in its degradation and may cause unexpected ecological effects. Nevertheless, little is known about the potential effects of MPs on reproduction toxicity in aquatic species. In this study, adult loach (Paramisgurnus dabryanus, F0 generation) were exposed to two concentrations (1 and 10 mg/L) of polyethylene MPs (PE-MPs) for 15 or 30 days, and the toxic effects in parental loach and the offspring (F1 generation) were examined. Our results showed that PE-MPs exposure could change the indicators content of antioxidant system in the brain, liver, and gonad. PE-MPs can accumulate in the gonads, disrupt the transcription of HPG-axis related genes, alter sex hormone levels, increase cell apoptosis and gonadal pathological lesions, lead to the damage of biological characteristics of semen, and affect the reproduction in F0 generation. PE-MPs remaining in the parental gonads can be transferred to the F1 generation embryos and accumulated on the embryonic chorionic membrane, increasing mortality and malformation rates, accelerating hatching time, and decreasing hatching rate and body length. These results suggest that PE-MPs leads to a potential adverse influence on reproduction and serious impacts on population sustainability. This work provides a new perspective into the effects of MPs on reproductive damage and cross-generational effects in teleost fish, which have implications in fields of freshwater ecology and environmental toxicology. [Display omitted] • PE-MPs could remain in the gonads and destroyed the reproductive organs. • PE-MPs could disturb the antioxidant, immune and endocrine system. • PE-MPs caused germ cell apoptosis and gamete quality decline. • PE-MPs transferred to the embryo chorionic membrane by parental transmission. • Parental exposure resulted in developmental toxicity of F1 larvae. [ABSTRACT FROM AUTHOR]

The present investigation was aimed to assess the effects of imidacloprid on the survival, genetic materials, hepatic transaminase activity and histopathology of loach ( Misgurnus anguillicaudatus ). The values of LC 50 (24, 48, 72 and 96 h) of imidacloprid were 167.7, 158.6, 147.9 and 145.8 mg/L, respectively, and the safety concentration was 42.55 mg/L. The erythrocyte micronuclei assays and the comet assay results showed that imidacloprid had genetic toxic effect on the loach erythrocytes. To assess the physiological and biochemical damage caused by imidacloprid, the activities of hepatic glutamic-pyruvic transaminase (GPT) and glutamic-oxalacetic transaminase (GOT) were measured and their values declined in treatment groups. Histological examination of testis revealed that imidacloprid treatment resulted in disorganized lobules and cysts structures. In the present work, we also investigated the joint toxicity of pesticides commonly used in paddy fields (imidacloprid and lambda-cyhalothrin) on M. anguillicaudatus , and confirmed that a synergistic effect existing in the binary mixtures. The results of our study provide relevant and comparable toxicity information that are useful for safety application of pesticides. [ABSTRACT FROM AUTHOR]

[Display omitted] • The toxicity effects of mixture and MCPA-Na were compared. • The herbicide mixtures caused a more serious lethal effect and teratogenicity. • The herbicide mixtures produced synergistic effect among embryos. • Explored the potential mechanism of synergistic effect caused by herbicide mixtures. Herbicides may pose considerable danger to non-target aquatic organisms and further threaten human health. The present investigation was aimed to assess the effects of 2-methyl-4-chlorophenoxy acetic acid (MCPA-Na) on Cyprinus carpio embryos. Embryos were exposed to six concentrations of MCPA-Na (0, 52, 54, 56, 58 and 60 mg/L) for 96 h. A series of symptoms were observed in developmental embryos during MCPA-Na exposure, including increased death, hatching inhibited and morphological deformities. Further, MCPA-Na exposure leading to a series of morphological changes (pericardial edema, tail deformation, and spine deformation) in embryos, which were consistent with modifications in the associated genes. In this work, we also investigated the joint toxicity of herbicides (MCPA-Na and cyhalofop-butyl) commonly used in paddy fields on carp embryos, using the 96 h-LC 50 of herbicides (59.784 mg/L MCPA-Na and 1.472 mg/L cyhalofop-butyl) and confirmed that a synergistic effect existing in the binary mixtures. [ABSTRACT FROM AUTHOR]

Dechlorane Plus (DP) is a widely used chlorinated flame retardant, which has been extensively detected in the environment. Although DP content in the surface water is low, it can pose a continuous exposure risk to aquatic organisms due to its strong bioaccumulation. Considering that the related studies on the toxicity mechanism of DP exposure are limited, the effect of DP on carp embryo development was evaluated. In the present work, carp embryos were exposed to different concentrations (0, 30, 60, and 120 μg/L) of DP at 3 h post-fertilization (hpf). The expression levels of neural and skeletal development-associated genes, such as sox2, sox19a, Mef2c and BMP4 , were detected with quantitative PCR, and the changes in different developmental toxicity endpoints were observed. Our results demonstrated that the expression levels of sox2, sox19a, Mef2c and BMP4 were significantly altered and several developmental abnormalities were found in DP-exposed carp embryos, such as DNA damage, increased mortality rate, delayed hatching time, reduced hatching rate, decreased body length, and increased morphological deformities. In addition, the activities of reactive oxygen species and malondialdehyde were remarkably higher in 60 and 120 μg/L DP exposure groups than in control group. These results suggest that DP can exhibit a unique modes of action, which lead to aberration occurrence in the early development stage of common carps, which may be related to some gene damage and oxidative stress. Besides, the parameters evaluated here can be used as tools to access the environmental risk for biota and humans exposed to DP. Image 1 • DP has embryotoxic effects on common carp. • DP could delay embryo development and even cause embryo death. • DP exposure could induce DNA damage and oxidative stress. • ROS and MDA may play an important role in DP-induced developmental deformity. [ABSTRACT FROM AUTHOR]

The occurrence and accumulation of microplastics in wildlife and humans have become a serious global scale concern over the last decade. To evaluate the potential toxic effects of PVC (polyvinyl chloride) microplastics in freshwater fish larvae, we conducted chronic 30-day and 60-day dietary exposure using Cyprinus carpio var. larvae. We exposed the larvae to four treatments with different microplastic concentrations (10%, 20%, and 30%) using food rationed diets, in conjunction with a non-plastic control. The results indicated that microplastics significantly inhibited weight gain and growth under all PVC treatments, compared to the control group. SOD (superoxide dismutase) and CAT (catalase) activities were analyzed, and an inverse relationship between them was observed. The activities of GPx (glutathione peroxidase) initially ascended and then descended with increased PVC concentrations following 30 days of exposure. A dose dependent downtrend was observed after 60 days of exposure. Malondialdehyde (MDA) levels were significantly reduced upon exposure to different concentrations of microplastics in various tissues. Altered antioxidant-related gene expression was observed in the livers of larvae exposed to the PVC microplastics. The transcription of CYP1A and GSTa initially increased, and then decreased under higher microplastics concentrations following 30 days of exposure. Furthermore, histological studies revealed cytoplasmic vacuolation in the liver under exposure to 20% and 30% microplastics. This investigation provided basic toxicological data toward elucidating and quantifying the impacts of PVC microplastics on freshwater organisms. Unlabelled Image • PVC microplastics inhibited weight gain and body length growth of carp larvae. • Antioxidant activities were altered following PVC microplastics exposure. • PVC microplastics influenced the expression levels of CYP1A , GSTpi , and GSTa. • Histological changes occurred in the livers of fish exposed to PVC microplastics. [ABSTRACT FROM AUTHOR]