Polyester microplastic fibers induce mitochondrial damage, apoptosis and oxidative stress in Daphnia carinata, accompanied by changes in apoptotic and ferroptosis pathway.

With the widespread utilization of plastic products, microplastics (MPs) have merged as a newfound environmental contaminant in the United States, and the bulk of these MPs in the environment manifest as fibrous structures. Concerns have also been voiced regarding the potential hazards posed by microplastic fibers (MFs). However, research examining the toxicity of MFs, particularly in relation to planktonic organisms, remains severely limited. Meanwhile, polyester fiber materials find extensive applications across diverse industries. As a result, this investigation delved into the toxicology of polyester microplastic fibers (PET-MFs) with a focus on their impact on Daphnia carinata (D. carinata), a freshwater crustacean. Newly hatched D. carinata were subjected to varying concentrations of PET-MFs (0, 50, and 500 MFs/mL) to scrutinize the accumulation of PET-MFs within these organisms and their resultant toxicity. The outcomes revealed that D. carinata was capable of ingesting PET-MFs, leading to diminished rates of survival and reproduction. These effects were accompanied by mitochondrial impairment, heightened mitochondrial count, apoptosis, escalated generation of reactive oxygen species, augmented activity of antioxidant enzymes, and distinct patterns of gene expression. Interestingly, when comparing the group exposed to 50 MFs/mL with the one exposed to 500 MFs/mL, it was observed that the former triggered a more pronounced degree of mitochondrial damage, apoptosis, and oxidative stress. This phenomenon could be attributed to the fact that brief exposure to 500 MFs/mL resulted in greater mortality, eliminating individuals with lower adaptability. Those that survived managed to regulate elevated in vivo reactive oxygen species levels through an increase in glutathione S-transferase content, thereby establishing an adaptive mechanism. Low concentrations did not induce direct mortality, yet PET-MFs continued to inflict harm within the organism. RNA-seq analysis unveiled significant alterations in 279 and 55 genes in the 50 MFs/mL and 500 MFs/mL exposure groups, respectively. Functional enrichment analysis of the 50 MFs/mL group indicated involvement of the apoptosis pathway and ferroptosis pathway in the toxic effects exerted by PET-MFs on D. carinata. This study imparts valuable insights into the toxicological ramifications of PET-MFs on D. carinata, underscoring their potential risks within aquatic ecosystems.

Toxicity of benzethonium chloride and polyhexamethylene guanidine hydrochloride mixtures on Daphnia carinata: synergistic and antagonistic effects at specific ratios.

Throughout the coronavirus (COVID-19) pandemic, the sanitizing products benzethonium chloride (BEC) and polyhexamethylene guanidine hydrochloride (PHMG-H) were widely used; however, few studies have investigated their combined toxicity to organisms. In the present study, acute toxicity and genotoxicity of BEC, PHMG-H, and the combination of the two were investigated as endpoints using Daphnia carinata as the model organism. For individual reagents, PHMG-H was found to be more toxic than BEC in terms of both mortality and genotoxicity. DNA damage and survival rate were used as toxicity endpoints. The interaction was evaluated with the concentration addition (CA) model via toxic unit (TU) approach and additive index (AI) method in mixtures at different ratios in TU. Only the binary mixture BEC + PHMG-H at the ratio 1:9 in TU was regarded as synergistic, while all others indicated increased antagonistic effects as the proportion of BEC increased over the PHMG-H concentration. The findings here benefit understanding surrounding precisely how BEC and PHMG-H interact at different mixing ratios, and can assist with the evaluation of risk assessments for binary mixtures in aquatic ecosystems.

NF-κB Inhibitor Myrislignan Induces Ferroptosis of Glioblastoma Cells via Regulating Epithelial-Mesenchymal Transformation in a Slug-Dependent Manner.

Glioblastoma (GBM) is the most common malignant tumor of the adult central nervous system. Aberrant regulation of cell death is an important feature of GBM, and investigating the regulatory mechanisms of cell death in GBM may provide insights into development of new therapeutic strategies. We demonstrated that myrislignan has ferroptosis-promoting activity. Myrislignan is a lignan isolated from Myristica fragrans Houtt and an inhibitor of NF-κB signaling pathway. Ferroptosis is an iron-dependent form of programmed cell death characterized by the accumulation of intracellular lipid peroxidation products. Interestingly, ferroptosis was associated with other biological processes in tumor cells such as autophagy and necroptosis. Recently, the crosstalk between epithelial-mesenchymal transition (EMT) and ferroptosis has also been reported, but the mechanisms underlying the crosstalk have not been identified. Our results indicated that myrislignan suppressed growth of GBM through EMT-mediated ferroptosis in a Slug-dependent manner. Myrislignan inhibited the activation of NF-κB signaling by blocking the phosphorylation of p65 protein and induced ferroptosis through the Slug-SLC7A11 signaling pathway in GBM cells. In addition, myrislignan suppressed the progression of GBM in xenograft mouse model. Hence, our findings contribute to the understanding of EMT-induced ferroptosis and provide targets for the development of targeted therapy against GBM.

Long-term BPA exposure leads to bone malformation and abnormal expression of MAPK/Wnt/FoxO signaling pathway genes in zebrafish offspring.

Bisphenol A (BPA) is one of the world's most widely used plasticizer, and its hazardous impacts have been well studied. However, few studies focused on the effects of parental long-term BPA exposure on the bone development of offspring. In the present study, the bone development of offspring was studied following long-term exposure of parental zebrafish to environmentally relevant 15 and 225 µg/L BPA. The results showed that BPA increased the mortality and deformity rate of offspring and caused craniofacial deformities characterized by changes in various cartilage angles and lengths. The alizarin red and calcein staining showed that BPA could delay bone mineralization and reduce bone mass accumulation. The results of acridine orange staining indicated that BPA induced apoptosis of the skull. The degree of harm of BPA presented a dose-dependent pattern. The results of the comparative transcriptome showed that there were 380 different expression genes (DEGs) in the 15 µg/L BPA group, and 645 DEGs in the 225 µg/L BPA group. MAPK/Wnt/FoxO signaling pathway-related genes were significantly down-regulated in the BPA-exposed groups. The present study demonstrates that long-term parental BPA exposure would severely affect cartilage development and bone mineralization of fish offspring, and MAPK/Wnt/FoxO signaling pathways may be involved in this process.

The toxic effects of polystyrene microplastics on freshwater algae Chlorella pyrenoidosa depends on the different size of polystyrene microplastics.

Microplastics (MPs) are persistent environmental contaminants. The toxic effects of MPs on aquatic organisms have raised increasing concerns, but their toxic effects on aquatic phytoplankton has not been thoroughly investigated. In the present study, the toxic effects of two sizes MPs (1 µm and 5 µm) on Chlorella pyrenoidosa at 2, 10, 50 mg/L were explored for 1, 5, 10 days. The growth ratio, photosynthetic pigments content, extracellular polymeric substances content, soluble protein content, MDA content and relative expression of genes related to photosynthesis and energy metabolism were measured. These results indicated that 1 µm MP could significantly inhibit the growth of C. pyrenoidosa. Compared with the control group, 1 µm MP significantly reduced the photosynthetic pigment content, induced oxidative stress and disrupted the cell membrane integrity of C. pyrenoidosa. At the molecular level, 1 µm MP altered the transcript levels of genes related to photosynthesis and energy metabolism. Scanning electron microscopy and fluorescent images showed that MPs aggregation with C. pyrenoidosa may be the main reason for the toxic effects of MPs. These results will provide new insight into the toxicity of different MPs on aquatic phytoplankton, and evaluate the risks caused by MPs in aquatic environments.

Body mass index change in relation to longitudinal systolic blood pressure: An age- and sex-matched and repeated measures study.

BACKGROUND AND AIMS: The positive association between mean systolic blood pressure (SBP) and body mass index (BMI) diminished or reversed over the past four decades. The primary aim of this study was to evaluate effects of BMI change on longitudinal SBP. METHODS AND RESULTS: A total of 3638 participants who had annual health examination from 2015 to 2019 were included and matched by age and sex according to BMI levels. BMI and SBP were measured annually and their association were assessed by a linear mixed-effects regression model. The normal weight participants had a sustained weight gain as well as SBP increase during the study period (all Ptrend <0.001). The obese participants had a sustained weight loss but SBP did not decrease simultaneously. If BMI change was considered, the obese participants with BMI loss had a significant decrease of SBP during the study period (Ptrend = 0.0012). Mixed-effects models showed that weight gain was more influential on longitudinal SBP in the normal weight participants and weight loss was in the obese participants. The obese group with BMI loss had a decrease of SBP by 5.01 mmHg (95% confidence interval: 2.56 mmHg, 7.46 mmHg) compared to their counterparts with BMI maintenance from 2015 to 2019. CONCLUSIONS: The effect of weight change on longitudinal SBP was varied among BMI groups. With the increase of baseline BMI level, the positive effect of weight loss on SBP became greater and the negative effect of weight gain on SBP were attenuated.

Transcriptome profiles of red swamp crayfish Procambarus clarkii hematopoietic tissue in response to WSSV challenge.

The crayfish Procambarus clarkii could achieve a high cumulative mortality after WSSV infections. To better understand the immune response to WSSV in hematopoietic tissue, the present study investigated the immunological response of P. clarkii and analyzed the expression of some hematopoietic cytokines. After assembly, there was an average of 47,712,411 clean reads were obtained in control and treatment groups. A total of 35,945 unigenes were discovered with N50 length of 1554 bp. Under functional classification, enrichment, and pathway analysis using different database, there were about 257 differentially expressed genes (DEGs) identified, of which 139 were up-regulated and 118 were down-regulated. The GO function analysis of these DEGs were mostly participated in activation of immune response, complement activation, complement binding, negative regulation of humoral immune response and secretory granule membrane. Under KEGG analysis, these DEGs were involved in ECM-receptor interaction, HIF-1 signaling pathway, Glycolysis/Gluconeogenesis, Thyroid hormone signaling pathway and Glucagon signaling pathway. The real-time quantitative PCR (RT-qPCR) analysis of 9 selected genes confirmed the reliability of RNA-Seq results. The present research provide for the first time the transcriptomic profile of P. clarkii hematopoietic tissue in response to WSSV infection and reveals the astakines may play important roles in antiviral immune response. The results of the present study will further enrich the theoretical basis of the crayfish immune system and provide new ideas for disease prevention and control.

Bisphenol A disturbs hepatic apolipoprotein A1 expression and cholesterol metabolism in rare minnow Gobiocypris rarus.

Bisphenol A (BPA) is a well-known plasticizer, which is widely distributed in the aquatic environment. Lots of studies showed that BPA could lead to lipid metabolism disorder in fish, but few studies studied the mechanism from the perspective of lipid transport. Apolipoprotein A1 (ApoA1) is the main component of high-density lipoprotein (HDL), and plays important roles in reverse cholesterol transport (RCT). In this study, we investigated the effect and molecular mechanism of BPA on ApoA1 and its effect on cholesterol in adult male rare minnow. Results showed that BPA could disturb hepatic ApoA1 expression through regulating Esrrg recruitment and DNA methylation in its promoter region, and ultimately up-regulated ApoA1 protein levels. The increased hepatic ApoA1 improved HDL-C levels, enhanced RCT, and disrupted cholesterol levels. The present study reveals the effect and mechanism of BPA on fish cholesterol metabolism from the perspective of cholesterol transport.

Bisphenol A disrupts apolipoprotein E expression through estrogen-related receptor gamma and DNA methlylation in the liver of male rare minnow Gobiocypris rarus.

An increasing number of studies show that bisphenol A (BPA) can cause lipid metabolism disorder. However, few studies focused on the effect of BPA on lipid transport. Apolipoprotein E (ApoE) plays important roles in triglyceride (TG) transportation. Our previous study found that ApoE was a sensitive gene in response to BPA exposure in male rare minnow. To investigate the effect and mechanism of BPA on hepatic ApoE, adult male rare minnow Gobiocypris rarus were exposed to environmentally relevant concentrations of BPA (15 µg/L) for 1, 3 and 5 weeks. Results showed that BPA inhibited ApoE expression at week 1 and 5, while induced its expression at week 3. A positive estrogen-related receptor gamma (Esrrg) response element was identified in the promoter region of ApoE. The change of the Esrrg recruitment was consistent with ApoE mRNA expression. Moreover, the methylation status of the CpG sites near and on the Esrrg binding sites changed opposite to the ApoE mRNA level, which may be the main cause for the change in Esrrg recruitment. The expression of ApoE protein was significantly enhanced following long-term BPA exposure. Consistently, the TG accumulation was significantly increased in the plasma. The present study demonstrates that BPA could affect rare minnow ApoE expression, which is probably one of the ways for BPA disturbing fish lipid metabolism.

Bisphenol A regulates apolipoprotein A1 expression through estrogen receptors and DNA methlylation and leads to cholesterol disorder in rare minnow testis.

Bisphenol A (BPA) is a well-known plasticizer that widely distributed in the aquatic environment. BPA has many adverse effects on reproduction. However, few studies have investigated the mechanism of BPA affecting reproduction from the perspective of lipid metabolism. Apolipoprotein A1 (ApoA1) is the major component of high-density lipoprotein (HDL), and plays critical roles in reverse cholesterol transport (RCT). In this study, in order to investigate the effect and molecular mechanism of BPA on testicular ApoA1 and the role of ApoA1 in BPA induced abnormal spermatogenesis, adult male rare minnow Gobiocypris rarus were exposed to 15 µg/L of BPA for 1, 3 and 5 weeks. Results showed that BPA could significantly affect testicular ApoA1 mRNA and protein levels, testicular cholesterol levels, plasmatic sex hormone levels and the integrity of sperm head membrane. The main mechanism of BPA regulating ApoA1 expression is to alter Esr recruitment and CpG sites DNA methylation in ApoA1 promoter. The induced ApoA1 up-regulated high density lipoprotein cholesterol levels and enhanced RCT, and finally decreased the testicular free cholesterol levels. This is likely a key mechanism by which BPA induces sex hormone disorder and sperm head membrane damage. The present study reveals the mechanism by which BPA interferes with spermatogenesis from the perspective of cholesterol transport.

Single and binary-combined toxic effects of acetochlor and Cu2+ on goldfish (Carassius auratus) larvae.

Acetochlor and copper are common freshwater pollutants and pose a severe threat to aquatic animals. The toxicity of acetochlor (Ac) and Cu2+ toward goldfish larvae was investigated by subjecting the larvae to different concentrations of acetochlor, Cu2+, and mixed solutions for 1, 3, and 7 days. The length of goldfish larvae exposed to the 100 µg/L Ac + 100 µg/L Cu2+ mixed solution was considerably lower than that of the control on day 3, but there were no significant differences among the other groups. The heart rates of the larvae in 100 µg/L Ac + 100 µg/L Cu2+ mixed solution were higher than those of the control group on days 3 and 7. Acetochlor and Cu2+ also caused severe damage to the liver and intestine of the larvae, especially in the 100 µg/L Ac + 100 µg/L Cu2+ mixed solution group. Indicators related to oxidative stress (hydrogen peroxide, catalase, glutathione peroxidase, and total superoxide dismutase) that could potentially be induced by acetochlor or Cu2+ began to increase on day 7, and the enzyme activities of the larvae in the mixed groups were significantly lower than those in the control group. In contrast, the expression levels of the genes related to antioxidant stress were rapidly down-regulated in all groups on the 7th day after exposure. Briefly, the combined toxicity of acetochlor and Cu2+ was stronger than that of the single toxicity treatments. Furthermore, toxicity toward larvae in the mixed solution group (100 µg/L Ac + 100 µg/L Cu2+) was more obvious.

Complete mitochondrial genome of Bosmina fatalis (Cladocera: Bosminidae) and its phylogenetic analysis.

Bosmina is a globally distributed zooplankton that adapts to a eutrophic environment. In this study, we cultivated monoclonal Bosmina fatalis and determined its complete mitochondrial gene sequence using the Illumina HiSeq 4000 platform. It was 15,209 bp in length, including 13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes, with the A + T content (69.2%) significantly higher than the G + C content (30.9%). All 22 typical tRNA genes had a classical cloverleaf structure, except for tRNAIle. The complete mitochondrial genome of nine other cladoceran species was used to reconstruct a phylogenetic tree, showing that B. fatalis has a closer relationship with Daphnia than other cladocerans.

Herbicide atrazine exposure induce oxidative stress, immune dysfunction and WSSV proliferation in red swamp crayfish Procambarus clarkii.

Atrazine is considered as a potential environmental endocrine disruptors and exhibits various toxic effects on animals. It has a great impact in the aquatic ecosystems, but there are few studies on its immunotoxicity in crustaceans. In the present study, the Procambarus clarkii were utilized to assess the immune toxicity after 0.5 mg/L and 5 mg/L atrazine exposure. A significant decrease in total hemocytes count (THC) was observed at 5 mg/L atrazine exposure throughout the experiment. The activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were significantly inhibited, but the content of reactive oxygen species (ROS) and malondialdehyde (MDA) were up-regulated, indicating the potential oxidative stress. The analysis of the integrated biomarker response (IBR) showed the induction of oxidative stress biomarkers and the inhibition of antioxidants. After 5 mg/L atrazine exposure for 144 h, the integrity of crayfish hepatopancreas was destroyed with disappeared connections between tubules and increased liver tubules vacuoles. The relative expression levels of different immune genes in hepatopancreas after atrazine exposure were measured. Most of these genes were suppressed and exhibited a certain dose-dependent effect. The results of crayfish white spot syndrome virus (WSSV) replication shown the amount of virus in muscle was significantly higher and exhibited a higher mortality rate at 5 mg/L group than other groups. The present study determined the impact of atrazine exposure on WSSV outbreaks, and also provide an important basis for further assessing the occurrence of pesticides on diseases of P. clarkii.

The identification of a nuclear factor Akirin with regulating the expression of antimicrobial peptides in red swamp crayfish (Procambarus clarkii).

Akirin is a highly conserved nuclear factor among different species. It is closely related to skeletal muscle development, innate immune response, and tumorigenesis in a variety of animals. In invertebrates, Akirin is mainly involved in gene transcription and NF-κB dependent natural immune response. In the present study, a nuclear factor Akirin was identified from Procambarus clarkii. The Akirin protein of crayfish consists of 204 amino acids and is conserved among its family members, especially the nuclear localization signal peptide motif (KRRR). PcAkirin was highly expressed in stomach, intestines, and hepatopancreas. After A. hydrophila challenge, the transcription level of Akirin significantly increased in hemocyte and hepatopancreas. In addition, the recombinant Akirin protein was produced successfully and helpful to resist WSSV infection by increasing the expression level of some immune related genes. On the contrary, after interfering with Akirin gene by dsRNA, the crayfish increased the sensitivity to A. hydrophila and WSSV infections. The results are more obvious in the accumulated mortality of P. clarkii infected with A. hydrophila and WSSV. All these results suggested that Akirin played a significant role in innate immune responses and protected it from WSSV and bacterial infection in crayfish.

Gut microbiomes of bigheaded carps and hybrids provide insights into invasion: A hologenome perspective.

Gut microbiomes play an essential role in host survival and local adaptation and thus can facilitate the invasion of host species. Biological invasions have been shown to be linked to the genetic properties of alien host species. It is thus plausible that the holobiont, the host, and its associated microbiome act as an entity to drive invasion success. The bighead carp and silver carp (bigheaded carps), invasive species that exhibit extensive hybridization in the Mississippi River Basin (MRB), provided a unique model to test the holobiont hypothesis of invasion. Here, we investigated the microbiomes of foreguts and hindguts in bigheaded carps and their reciprocal hybrids reared in aquaculture ponds using 16S amplicons and the associated gene prediction. We found an admixed pattern in the gut microbiome community in bigheaded carp hybrids. The hybrid gut microbiomes showed special characteristics such as relatively high alpha diversity in the foregut, an increasing dissimilarity between foreguts and hindguts, and a remarkable proportion of genes coding for putative enzymes related to their digestion of main food resources (Cyanobacteria, cellulose, and chitin). The pond-reared hybrids had advantageous features in genes coding for putative enzymes related to their diet. The above results collectively suggested that the gut microbiomes of hybrids could be beneficial to their local adaptation (e.g., food resource utilization), which might have facilitated their invasion in the MRB. The gut microbial findings, along with the intrinsic genomic features likely associated with life-history traits revealed in our recent study, provide preliminary evidence supporting the holobiont hypothesis of invasion.

Bisphenol A induces hepatic triglyceride level in adult male rare minnow Gobiocypris rarus.

Bisphenol A (BPA), an endocrine disruptor, exist in almost all waters. In the present study, we expose adult male Gobiocypris rarus rare minnow to 15 µg/L BPA to study the effect BPA on fish hepatic lipid metabolism. Following 1, 3 and 5 weeks exposure, the liver tissue of rare minnow was separated. The change of the hepatic morphology, hepatosomatic index, lipid composition and expression of lipid metabolism related genes were analyzed through paraffin section, oil red O staining, lipidomic analysis, and quantitative real-time PCR. BPA can cause significant hepatic lipid deposition in male rare minnow, leading to an increase in triglyceride (TG) level (1.84-22.87-fold), but it is also accompanied by a decrease in diglyceride level (1.67-4.78-fold). The expression of lipid metabolism related genes showed that BPA exposure can up-regulate TG synthesis related genes expression, and down-regulate TG degradation genes expression. Expression of TG transport related genes were also disrupted by BPA. It suggests that BPA can up-regulate rare minnow hepatic TG level through multi-path, and ultimately lead to lipid accumulation in the liver. The results of the present study enrich the mechanisms of environmental endocrine disruptors affecting lipid accumulation in fish.

A trypsin-like serine protease domain of masquerade gene in crayfish Procambarus clarkii could activate prophenoloxidase and inhibit bacterial growth.

Masquerade (Mas) is a secreted trypsin-like serine protease (SPs) and involved in immune response in some arthropods. However, according to previous studies, Mas presents different functional activities. In the present study, the functional mechanisms of Mas in crayfish Procambarus clarkii immune defense were studied. A fragment cDNA sequence of PcMas was identified and characterized. From the structural analysis, it contains a trypsin-like serine protease domain. The highest expression level of PcMas was detected in hepatopancreas. The infection of A. hydrophila could induce the expression of PcMas, while the WSSV infection did not cause changes in the expression of PcMas. Through the prokaryotic expression system, the PcMas protein was expressed in E. coli. It was verified that PcMas can bind to bacteria in vitro and inhibit the growth of the bacteria. By dsRNA interference with the expression of PcMas, the decrease expression of PcMas led to a decrease in the activity of phenoloxidase in hemolymph and an increase of mortality caused by A. hydrophila infection. The injection of recombinant protein can enhance the activity of phenoloxidase and reduce mortality caused by A. hydrophila infections. Therefore, the present study confirmed that PcMas could improve the body's immune response to eliminate bacterial pathogens by binding with bacteria and activating the prophenoloxidase system. The results will enrich the molecular mechanisms of crustaceans immune defense.

Acetochlor affects zebrafish ovarian development by producing estrogen effects and inducing oxidative stress.

Acetochlor is one of the most widely used pesticides worldwide and widely distributed in the water environment. However, studies on the reproductive influence of acetochlor are still limited. To investigate the impact and potential mechanism of acetochlor on fish ovarian development, zebrafish were utilized as experiment models. The ovarian histology, ovarian development-related genes, and plasma oxidative stress-related indexes were investigated following acetochlor (at nominal concentration 1, 10, and 100 µg/L) exposure for 7 and 21 days. Results showed that low-dose acetochlor had estrogen effect and induced zebrafish estradiol (E2) and ovarian vitellogenin (Vtg) synthesis and promoted ovarian development, while long-term exposure to higher doses of acetochlor reduced the ability of ovarian resistance to oxidative stress and destroyed the development of the ovary. Moreover, bone morphogenetic protein 15 (bmp15) and growth differentiation factor 9 (gdf9) were also involved in the influence of acetochlor on the ovarian development of zebrafish.

Acute BPA exposure-induced oxidative stress, depressed immune genes expression and damage of hepatopancreas in red swamp crayfish Procambarus clarkii.

Bisphenol A is a typical endocrine disrupting chemicals (EDCs) and produce various toxic effects on animals due to its potential endocrine disruption, oxidative damage effect, mutagenic effect and hypomethylation. To study its effect on the immune system of crustaceans, the Procambarus clarkii were utilized to detect the immune related indicators after 225 µg/L BPA exposure for 1 week. Hepatopancreatic histology and ultrastructure analysis showed that the brush border disappeared, the lumen increased, and the connection between the hepatic tubules fade away in BPA treated group. BPA could significantly increase the level of ROS, inhibit the activities of antioxidant-related enzymes (SOD, POD, and CAT), and thereby cause the oxidative stress. The enzyme activities of AKP, ACP and lysozyme in hepatopancreas after BPA exposure were also depressed even after Aeromonas hydrophila infections. The relative expression profiles of immune-related genes after BPA exposure and bacterial infection showed suppressed trends of most selected genes. Under A. hydrophila infections, the cumulative mortality of 225 µg/L BPA-treated crayfish was significantly higher than other groups. All these results indicated that BPA exposure had adverse effects on the immune ability of P. clarkii. The present study will provide an important foundation for further understanding the effects of EDCs on crustacean immune functions.

Toxicity comparison of nano-sized and micron-sized microplastics to Goldfish Carassius auratus Larvae.

Plastic pollution is one of the most serious environmental issues worldwide. The negative influence of plastics on aquatic organisms has increasingly concerned, especially the influence of microplastic (MPs). In the present study, the toxicology of nano-sized MPs (nMPs) and micron-sized MPs (mMPs) were comparatively studied. Goldfish larvae were exposed to 10, 100 and 1000 µg/L nMPs and mMPs for 1, 3 and 7 days. The enrichment of MPs, body length, heart rate, motor ability, microscopic and ultrastructure of intestine, liver, gill and muscle tissue, as well as the oxidative stress were analyzed. Results showed that both 70 nm and 50 µm MPs were accumulated in the digestive tract of larvae. MPs at high concentrations could induce oxidative stress, destroy intestine, liver and gill tissues, increase heart rate, and inhibit growth and swimming speed of the larvae. The most important finding was that nMPs could enter into the muscle tissue through the epidermis of the larvae. It could cause damage to muscle tissue, destroy nerve fibers, inhibit acetylcholinase (AchE) activity, and show great adverse effects on larval movement than mMPs. In conclusion, both nMPs and mMPs at higher concentrations can cause damage to fish larvae and nMPs are potentially more hazardous.