Short daylight photoperiod alleviated alarm substance-stimulated fear response of zebrafish.

Photoperiod has been well-documented to be involved in regulating many activities of animals. However, whether photoperiod takes part in mood control, such as fear response in fish and the underlying mode(s) of action remain unclear. In this study, adult zebrafish males and females (Danio rerio) were exposed to different photoperiods, Blank (12 h light: 12 h dark), Control (12 h light: 12 h dark), Short daylight (SD, 6 h light: 18 h dark) and Long daylight (LD, 18 h light: 6 h dark) for 28 days. After exposure, fear response of the fish was investigated using a novel tank diving test. After alarm substance administration, the onset to higher half, total duration in lower half and duration of freezing in SD-fish were significantly decreased, suggesting that short daylight photoperiod is capable of alleviating fear response in zebrafish. In contrast, comparing with the Control, LD didn't show significant effect on fear response of the fish. Further investigation revealed that SD increased the levels of melatonin (MT), serotonin (5-HT) and dopamine (DA) in the brain while decreased the plasma level of cortisol comparing to the Control. Moreover, the expressions of genes in MT, 5-HT and DA pathways and HPI axis were also altered consistently. Our data indicated that short daylight photoperiod might alleviate fear response of zebrafish probably through interfering with MT/5-HT/DA pathways and HPI axis.

Chronic exposure to environmentally relevant concentrations of carbamazepine interferes with anxiety response of adult female zebrafish through GABA /5-HT pathway and HPI axis.

Carbamazepine (CBZ) is one of the widely distributed pharmaceutical residues in aquatic environments, yet few researches have addressed its chronic effect on the anxiety of fish, and the mechanisms possibly involved remained elusive. In this study, adult female zebrafish (Danio rerio) were exposed to environmental relevant concentrations of CBZ (CBZ-low, 10 µg/L; CBZ-high, 100 µg/L) for 28 days. After exposure, CBZ-high didn't affect the anxiety of fish. However, the onset time to the higher half of the tank was delayed and the total duration in the lower half of the tank was increased in CBZ-low fish, suggesting an increased anxiety. Further investigation indicated that CBZ-low significantly decreased the gamma-aminobutyric acid (GABA) level in the brain, while increased the serotonin (5-HT) level in the brain and cortisol level in plasma. Accordingly, the mRNA levels of genes in GABA (gad2, abat, gabrb2, gabrg2, gria1a and slc12a2) pathway and HPI (crha, actha, pc1 and pc2) axis were also altered. Despite the upregulation of tph2 was consistent with increased 5-HT level in the brain, significantly downregulated htr1aa and htr1b may indicate attenuated 5-HT potency. Although CBZ-high significantly reduced GABA level in the brain and increased cortisol level in plasma, the effects were dramatically alleviated than that of CBZ-low. Consistently, the expression of genes in HPI (crha, actha, pc1 and pc2) axis and GABA (gad2 and abat) pathway were also altered by CBZ-high, probably due to inconspicuous anxiety response of CBZ-high. Briefly, our data suggested that low concentration of CBZ disrupted zebrafish anxiety by interfering with neurotransmission and endocrine system, thereby bringing about adverse ecological consequences.

Small intestinal angiosarcoma on clinical presentation, diagnosis, management and prognosis: A case report and review of the literature.

BACKGROUND: Angiosarcoma is a highly malignant soft-tissue sarcoma derived from vascular endothelial cells that mainly occurs in the skin and subcutaneous tissues. Small-intestinal angiosarcomas are rare, and the prognosis is poor. CASE SUMMARY: We reported a case of primary multifocal ileal angiosarcoma and analyze previously reported cases to improve our understanding of small intestinal angiosarcoma. Small intestinal angiosarcoma is more common in elderly and male patients. Gastrointestinal bleeding, anemia, abdominal pain, weakness, and weight loss were the common symptoms. CD31, CD34, factor VIII-related antigen, ETS-related gene, friend leukemia integration 1, and von Willebrand factor are valuable immunohistochemical markers for the diagnosis of small-intestinal angiosarcoma. Small-intestinal angiosarcoma most commonly occurs in the jejunum, followed by the ileum and duodenum. Radiation and toxicant exposure are risk factors for angiosarcoma. After a definite diagnosis, the mean and median survival time was 8 mo and 3 mo, respectively. Kaplan-Meier survival analysis showed that age, infiltration depth, chemotherapy, and the number of small intestinal segments invaded by tumor lesions were prognostic factors for small intestinal angiosarcoma. Multivariate Cox regression analysis showed that chemotherapy and surgery significantly improved patient prognosis. CONCLUSION: Angiosarcoma should be considered for unexplained melena and abdominal pain, especially in older men and patients with a history of radiation exposure. Prompt treatment, including surgery and adjuvant chemotherapy, is essential to prolonging patient survival.

Correlation Between IVIM-DWI Parameters and Pathological Classification of Idiopathic Orbital Inflammatory Pseudotumors: A Preliminary Study.

Objective: To investigate the correlation between intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and the pathological classification of idiopathic orbital inflammatory pseudotumors (IOIPs). Methods: Nineteen patients who were diagnosed with IOIPs (a total of 24 affected eyes) between November 2018 and December 2020 were included in the study. All the patients underwent magnetic resonance imaging orbital plain scans and IVIM-DWI multiparameter scans before an operation. The true diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) values were obtained. Based on histopathology, the lesions were divided into three types: lymphocytic infiltration, fibrosclerotic, and mixed. The correlation between IVIM-DWI parameters and pathological classification was tested with the histopathological results as the gold standard. The data were analyzed using SPSS version 17.0, with P < 0.05 defined as significant. Results: Among the 19 patients (24 eyes) affected by IOIP, there were no significant differences between IOIP pathological classification and gender or age (P > 0.05). There were statistically significant differences between the D and f values for different pathological types of IOIP and IVIM parameters (P < 0.05), and there was no significant difference in D* value between the different pathological types (P > 0.05). Conclusion: The D and f values showed correlation with different types of IOIP, and the sensitivity of the D value was higher than that of the f value. The D* value showed no significant distinction between pathological types of IOIP.

SARS-CoV-2 spike spurs intestinal inflammation via VEGF production in enterocytes.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) can cause gastrointestinal (GI) symptoms that often correlate with the severity of COVID-19. Here, we explored the pathogenesis underlying the intestinal inflammation in COVID-19. Plasma VEGF level was particularly elevated in patients with GI symptoms and significantly correlated with intestinal edema and disease progression. Through an animal model mimicking intestinal inflammation upon stimulation with SARS-CoV-2 spike protein, we further revealed that VEGF was over-produced in the duodenum prior to its ascent in the circulation. Mechanistically, SARS-CoV-2 spike promoted VEGF production through activating the Ras-Raf-MEK-ERK signaling in enterocytes, but not in endothelium, and inducing permeability and inflammation. Blockage of the ERK/VEGF axis was able to rescue vascular permeability and alleviate intestinal inflammation in vivo. These findings provide a mechanistic explanation and therapeutic targets for the GI symptoms of COVID-19.

Tributyltin enhanced anxiety of adult male zebrafish through elevating cortisol level and disruption in serotonin, dopamine and gamma-aminobutyric acid neurotransmitter pathways.

Tributyltin (TBT), a widely and persistently distributed organontin, has been well documented to disrupt reproduction and behaviors in animals due to its anti-aromatase activity. TBT has been also reported to enhance anxiety in several fish species, whereas the mechanism underlying remains largely unknown. To investigate the disruption of TBT on fish anxiety and the mechanisms possibly involved, adult male zebrafish (Danio rerio) were treated with TBT (100 and 500 ng/L) for 28 days and anxiety behavior was further investigated using a novel tank dive test. Result showed that TBT treatment significantly enhanced the total time of the fish spent in the lower half, delayed the onset time to the higher half of the tank and increased the total duration of freezing of the fish, indicating an enhanced anxiety in TBT-treated fish. Accordingly, TBT sharply elevated the cortisol levels in plasma in a concentration-dependent manner, suggesting that the elevated cortisol level might be involved in the enhanced anxiety. Although the expression of crha was significantly increased and crhbp was significantly decreased in the brain of TBT-treated fish which is consistent to the elevated cortisol level, the expressions of actha and acthb were sharply down-regulated. In contrast, the expressions of genes responsible for the synthesis and action of serotonin (5-HT) (pet1, thp2 and htr1aa), dopamine (DA) (th1, slc6a3, drd2a and drd2b) and gamma-aminobutyric acid (GABA) (gad2 and gabrg2) were all significantly inhibited. The down-regulation of these pivotal genes acting in 5-HT, DA and GABA neurotransmitter systems in response to TBT corresponded well with the TBT-enhanced anxiety in fish. It was thus strongly suggested that these neurotransmitters might be also involved in TBT-enhanced anxiety in adult male zebrafish. The present study extended our understanding of the neurotoxicity of TBT on the anxiety control and behavioral modulation in fish.

Tributyltin impaired spermatogenesis and reproductive behavior in male zebrafish.

Tributyltin (TBT) was reported to affect sexual behavior and gametogenesis in fish. However, the modes of action involved are largely unclear. In order to elucidate the toxicological mechanisms of TBT in reproduction, zebrafish (Danio rerio) males were exposed to TBT at concentrations of 100 and 500 ng/L for 28 days. After exposure, the sperm count of the treated fish was sharply decreased though the testis weight and gonadosomatic index remained unchanged. Moreover, reduced number of spermatogonia and spermatozoa and increased spermatocytes were observed in TBT-treated fish by histological observation and PCNA-immunostaining. Increased number of apoptotic-positive spermatocytes was also present in TBT-treated fish, indicating an enhanced apoptosis in these cells. Consistent to decreased number of spermatogonia, down-regulated expressions of genes responsible for germ cell proliferation (cyclind1 and pcna) were observed in TBT-treated fish. In contrast, TBT elevated the expressions of genes involved in meiotic entry and maintenance (aldhla2, sycp3 and dmc1) while suppressed the mRNA level of gene responsible for terminus of meiotic entry (cyp26a1), in agreement with arrested meiosis and reduced sperm count. Furthermore, TBT significantly elevated the ratios of bax/bcl-2 and tnfrsf1a/tnfrsf1b in testis, which are markers for intrinsic- and extrinsic-apoptotic pathways, consistent with the enhanced TUNEL positive signals in spermatocytes. Moreover, TBT also significantly affected the parameter of reproductive behaviors in treated fish (reflected by decreased frequency of meeting, visits and time spent in spawning area). Consistently, the expressions of genes responsible for the modulation of reproductive behaviors in brain (such as cyp19a1b, kiss2, gnrh3 and ompb) were significantly down-regulated in treated-fish. Interestingly, disrupted reproductive behaviors of untreated female fish were also observed in the present study. The present study indicated that TBT might affect the reproduction of zebrafish male by disrupting the spermatogenesis and reproductive behavior of the fish.

Mechanisms involved in tributyltin-enhanced aggressive behaviors and fear responses in male zebrafish.

Tributyltin (TBT), an aromatase inhibitor, has been found to disrupt gametogenesis and reproductive behavior in several fish species. However, whether TBT is capable of affecting other behaviors such as aggressive behavior and fear response in fish and the underlying mode(s) of action remain unclear. To study aggressive behavior, adult zebrafish (Danio rerio) males were continuously exposed to two nominal concentrations of TBT (TBT-low, 100 ng/L and TBT-high, 500 ng/L) for 28 days. To study the fear response, the fish were divided into four groups (Blank and Control, 0 ng/L TBT; TBT-low, 100 ng/L; and TBT-high, 500 ng/L). The fish were then treated with DW (Blank) or with alarm substance (AS) (Control, TBT-low and TBT-high). After exposure, the aggressive behavior of the fish was tested using the mirror test (mirror-biting frequency, approaches to the mirror and duration in approach zone).and fighting test (fish-biting frequency) The mirror-biting frequency, approaches to the mirror, duration in approach zone and fish-biting frequency of the TBT-exposed fish increased significantly compared to those of the control fish, indicating enhanced aggressive behavior. The fear response parameters tested using the novel tank dive test (onset time to the higher half, total duration in the lower half and the frequency of turning) of the TBT-exposed fish were also significantly increased after AS administration, suggesting an enhanced fear response. Further investigation revealed that TBT treatment elevated the plasma level of 11-ketotestosterone (11-KT) and decreased the plasma level of estradiol (E2) in a concentration-dependent manner. Moreover, TBT up-regulated the mRNA levels of ar, c-fos and bdnf1, and suppressed the expression of btg-2 in fish. In addition, exposure to AS increased the plasma level of cortisol and down-regulated the mRNA expression levels of genes involved in 5-HT synthesis (such as tph1b and pet1) in both control and TBT-treated fish. AS significantly suppressed the mRNA level of tph1b, tph2, pet1 and npy in the TBT-high group compared to the control fish. The present study demonstrates that TBT enhances aggressive behavior and fear responses in male zebrafish probably through altering plasma levels of 11-KT, E2 and cortisol and altering the expression of genes involved in the regulation of aggressive behavior (ar, c-fos, bdnf1 and btg-2) and fear responses (tph1b, tph2, pet1 and npy). The present study greatly extends our understanding of the behavioral toxicity of TBT to fish.

Long-term exposure of xenoestrogens with environmental relevant concentrations disrupted spermatogenesis of zebrafish through altering sex hormone balance, stimulating germ cell proliferation, meiosis and enhancing apoptosis.

Environmental estrogens are capable of interfering with the spermatogenesis and fertility of fish. However in natural waters, these chemicals are more likely to occur as a combination rather than a single stressor. Whether and how the mixture of xenoestrogens with environmental relevant concentrations may affect fish spermatogenesis remains largely unknown. In this study, male zebrafish adults were administered to 17alpha-ethinylestradiol (EE2) and a mixture of xenoestrogens (Mix (E2, EE2, DES, 4-t-OP, 4-NP and BPA)), with the estrogenic potency equivalent to EE2. After a 60-day exposures, elevated mRNA levels of vitellogenin 1 (vtg1) and estrogen receptor 1 (esr1) in the liver of fish in both treated groups were observed. Moreover, the plasma level of E2 declined significantly in the Mix group and the ratio of 11-KT/E2 was significantly elevated in both treated groups. Consistently, the mRNA level of P450 side-chain cleavage (scc) in the EE2 group and ovarian type aromatase (cyp19a1a) in the Mix group was significantly suppressed. In addition, decreased gonadosomatic index and sperm count in the fish of Mix group were present. Furthermore, increased number of the proliferating germ cells (such as spermatogonia and spermatocytes) was observed in the fish of both groups, suggesting a stimulated germ cell proliferation and meiosis. Accordingly, both exposures significantly up-regulated the mRNA levels of genes in mitosis (cyclinb1) and meiosis (cyp26a1 in EE2 group, aldh1a2, cyp26a1, sycp3 and spo11 in Mix). In addition, decreased number of spermatozoa and increased number of TUNEL-positive signals were present in the testis of fish in the Mix group, indicating an enhanced apoptosis. Further analyses demonstrated the significant elevated expressions of tnfrsf1a and the ratio of tnfrsf1a/tnfrsf1b in the Mix group, suggesting an elevated apoptosis in the testis of fish in the Mix group via extrinsic pathway. The present study greatly extends our understanding of the underlying mechanisms of the reproductive toxicity of xenoestrogens on fish.

Tributyltin impaired reproductive success in female zebrafish through disrupting oogenesis, reproductive behaviors and serotonin synthesis.

Tributyltin (TBT), an organotin acting as aromatase (Cyp19a1) inhibitor, has been found to disrupt gametogenesis and reproductive behaviors in several fish species. However, few studies addressing the mechanisms underlying the impaired gametogenesis and reproduction have been reported. In this study, female adults of zebrafish (Danio rerio) were continuously exposed to two nominal concentrations of TBT (100 and 500 ng/L, actual concentrations: 90.8 ±â€¯1.3 ng/L and 470.3 ±â€¯2.7 ng/L, respectively) for 28 days. After exposures, TBT decreased the total egg number, reduced the hatchability and elevated the mortality of the larvae. Decreased gonadosomatic index (GSI) and altered percentages of follicles in different developmental stages (increased early-stage follicles and reduced mid/late-stage follicles) were also observed in the ovary of TBT-treated fish. TBT also lowered the plasma level of 17ß-estradiol and suppressed the expressions of cyp19a1a in the ovary. In treated fish, up-regulated expressions of aldhla2, sycp3 and dmc1 were present in the ovary, indicating an enhanced level of meiosis. The mRNA level of vtg1 was dramatically suppressed in the liver of TBT-treated fish, suggesting an insufficient synthesis of Vtg protein, consistent with the decreased percentage of mid/late-stage follicles in the ovaries. Moreover, TBT significantly suppressed the reproductive behaviors of the female fish (duration of both sexes simultaneously in spawning area, the frequency of meeting and the visit in spawning area) and down-regulated the mRNA levels of genes involved in the regulation of reproductive behaviors (cyp19a1b, gnrh-3 and kiss 2) in the brain. In addition, TBT significantly suppressed the expressions of serotonin-related genes, such as tph2 (encoding serotonin synthase), pet1 (marker of serotonin neuron) and kiss 1 (the modulator of serotonin synthesis), suggesting that TBT might disrupt the non-reproductive behaviors of zebrafish. The present study demonstrated that TBT may impair the reproductive success of zebrafish females probably through disrupting oogenesis, disturbing reproductive behaviors and altering serotonin synthesis. The present study greatly extends our understanding on the reproductive toxicity of TBT on fish.

Diethylstilbestrol arrested spermatogenesis and somatic growth in the juveniles of yellow catfish (Pelteobagrus fulvidraco), a fish with sexual dimorphic growth.

In fish, spermatogenesis and somatic growth are mainly regulated by hypothalamic-pituitary-gonadal (HPG) and hypothalamic-pituitary-somatic (HPS) axes, respectively. Xenoestrogens have been reported to impair spermatogenesis in some fishes, and arrest somatic growth in some others, whereas, whether xenoestrogens are capable of disrupting spermatogenesis and somatic growth simultaneously in fish that exhibits sexual dimorphic growth is little known, and the underlying mechanisms remain poorly understood. In this study, male juveniles of yellow catfish (Pelteobagrus fulvidraco), which exhibits a sexual dimorphic growth that favors males, were exposed to diethylstilbestrol (DES) for 28 days. After exposure, DES significantly disrupted the spermatogenesis (decreased gonadal-somatic index (GSI) and germ cell number) and arrested the somatic growth (declined body weight) of the catfish juveniles. Gene expression and plasma steroid analyses demonstrated the suppressed mRNA levels of genes in HPG axis (gnrh-II, fshß, and lhß in the brain and dmrt1, sf1, fshr, cyp17a1, cyp19a1a, and cyp11b2 in the testis) and decreased 17ß-estrodial (E2) and 11-ketotestosterone (11-KT) levels in plasma. Further analysis revealed the arrested germ cell proliferation (cyclin d1), meiosis (dmc1, sycp3), and enhanced apoptosis (decreased bcl-2 and elevated bax/bcl-2 ratio) in the testis. Besides, DES also suppressed the mRNA levels of genes in HPS axis (ghrh, gh, and prl in the brain and ghr, igf1, igf2a, and igf2b in the liver). The suppressed HPG and HPS axes were thus supposed to disturb spermatogenesis and arrest somatic growth in yellow catfish. The present study greatly extended our understanding on the mechanisms underlying the toxicity of DES on spermatogenesis and somatic growth of fish.

Functional polymorphism rs3783553 in the 3'-untranslated region of IL-1A increased the risk of ischemic stroke: A case-control study.

Accumulating evidence indicates interleukin-1 (IL-1) is a critical mediator of inflammatory responses in ischemic stroke (IS). The aim of this study was to investigate whether rs3783553 in the 3'-untranslated region of IL-1A was associated with the risk of IS. In this hospital-based case-control study, we genotyped the rs3783553 using polymerase chain reaction in 316 patients with IS and 332 age, sex, and ethnicity-matched controls. Plasma level of IL-1α was measured by enzyme-linked immunosorbent assay. The relative luciferase activities were measured by the Dual Luciferase assay system. The presence of ins/ins genotype was associated with higher odds ratios (ORs) of IS compared with del/del genotype (ins/ins vs del/del: adjusted OR 1.77, 95% confidence interval [CI] 1.06-2.98; recessive model: adjusted OR 1.69, 95% CI 1.06-2.70). The higher risk of IS was also observed in allele comparison (adjusted OR 1.29, 95% CI 1.00-1.65). Multivariate logistic regression analysis showed that age, hypertension, total cholesterol, triglyceride, low-density lipoprotein, and rs3783553ins/ins genotypes were independent risk factors for IS. Plasma level of IL-1α was higher among IS patients compared with controls (P = .03). Notably, IS patients with the TTCA/TTCA genotype had a higher level of IL-1α compared with those with the del/del genotype (P = .01). Luciferase reporter assay showed that the vector containing the TTCA del allele exhibited a reduced transcriptional activity in the presence of miR-122 and miR-378. These findings indicate that IL-1A rs3783553 ins/ins genotype may increase the susceptibility to IS, possibly by interrupting the binding site of miR-122 and miR-378.

Sex-dependent effects of subacute mercuric chloride exposure on histology, antioxidant status and immune-related gene expression in the liver of adult zebrafish (Danio rerio).

Mercury (Hg) is a global pollutant that causes negative health effects. In order to assess Hg-induced hepatotoxicity in fish and examine whether gender differences existed in response to Hg exposure, adult zebrafish were exposed to 0, 15 and 30 µg L-1 Hg2+ for 30 days, and histology, antioxidant status and the transcription levels of several immune-related genes were examined in the liver. Hg2+ exposure caused a dose-dependent increase in histopathological lesions of the liver, including vacuolization, parenchyma disorganization and pyknotic nucleus, and these lesions were more severe in males than in females. In females, Hg2+ exposure decreased CAT activity and its mRNA levels, while increased GSH content and the expressions of sod1, gpx1a, gstr and keap1. In males, the decrease in cat1 expression and the increase in GST activity, GSH and MDA contents as well as gpx1a, gstr, nrf2 and keap1 mRNA levels were observed in Hg2+-exposed groups, but the activities of CAT, SOD and GPX were only stimulated in the 15 µg L-1 Hg2+ group. Moreover, both in females and males, Hg2+ exposure down-regulated il-8 expression while up-regulated il-10 and lyz mRNAs. However, the down-regulation of il-1ß and tnfα was detected only in males under Hg2+ treatments. Thus, our results indicated that HgCl2 exposure induced histopathological damage, oxidative stress and immunotoxicity in the liver of zebrafish. Different response patterns of histology, antioxidant status and immune defenses to Hg2+ between females and males suggested sex-dependent effects of Hg, and males showed more vulnerable to Hg2+ exposure than females.

Diethylstilbestrol, flutamide and their combination impaired the spermatogenesis of male adult zebrafish through disrupting HPG axis, meiosis and apoptosis.

Both diethylstilbestrol (DES, an environmental estrogen) and flutamide (FLU, an anti-androgen) are found to impair spermatogenesis by disrupting hypothalamic-pituitary-gonadal (HPG) axis and altering androgen levels through different mechanisms/modes of action in fish with poorly understood underlying mechanisms. Furthermore, it is not known whether and how a combined exposure of DES and FLU has a stronger effect than the compounds alone. In this study, male zebrafish adults were exposed to DES, FLU and their combination (DES+FLU) for 30days, and their effects on histological structure and sperm count in testis, androgen level in plasma, as well as the mRNA levels of genes involved in HPG axis, meiotic regulation and apoptosis were analyzed. After exposure, DES and FLU disrupted spermatogenesis in zebrafish, and their combination resulted in even more severe impairment, indicating the inhibitory roles of these chemicals on spermatogenesis and their additive effects on zebrafish. The different regulation of vtg1 expression in the liver in response to DES and FLU further confirmed the different modes of action of these drugs. Gene expression and plasma steroid level analyses demonstrated the suppressed mRNA levels of the key genes (such as gnrh3, fshß and lhß in brain and dmrt1, sf1, cyp17a1 and cyp11b2 in testis) in HPG axis and decreased 11-ketotestosterone (11-KT) levels in plasma. The declined level of 11-KT was thus supposed to be closely related to the down-regulation of cyp26a1 (encoding the catabolic enzyme of retinoic acid) and suppression of genes involved in meiotic regulation (nanos1, dmc1 and sycp3). In fish exposed to DES and DES+FLU, enhanced apoptosis (elevated bax/bcl-2 expression ratio) was also observed. The suppression of meiotic regulation in response to all the exposures and enhanced apoptosis in response to DES were thus supposed to result in the spermatogenic impairment in zebrafish. The present study greatly extends our understanding on the mechanisms underlying of reproductive toxicity of environment estrogens and anti-androgens in fish.

Exposure to mercuric chloride induces developmental damage, oxidative stress and immunotoxicity in zebrafish embryos-larvae.

Mercury (Hg) is a widespread environmental pollutant that can produce severe negative effects on fish even at very low concentrations. However, the mechanisms underlying inorganic Hg-induced oxidative stress and immunotoxicity in the early development stage of fish still need to be clarified. In the present study, zebrafish (Danio rerio) embryos were exposed to different concentrations of Hg2+ (0, 1, 4 and 16µg/L; added as mercuric chloride, HgCl2) from 2h post-fertilization (hpf) to 168hpf. Developmental parameters and total Hg accumulation were monitored during the exposure period, and antioxidant status and the mRNA expression of genes related to the innate immune system were examined at 168hpf. The results showed that increasing Hg2+ concentration and time significantly increased total Hg accumulation in zebrafish embryos-larvae. Exposure to 16µg/L Hg2+ caused developmental damage, including increased mortality and malformation, decreased body length, and delayed hatching period. Meanwhile, HgCl2 exposure (especially in the 16µg/L Hg2+ group) induced oxidative stress affecting antioxidant enzyme (CAT, GST and GPX) activities, endogenous GSH and MDA contents, as well as the mRNA levels of genes (cat1, sod1, gstr, gpx1a, nrf2, keap1, hsp70 and mt) encoding antioxidant proteins. Moreover, the transcription levels of several representative genes (il-1ß, il-8, il-10, tnfα2, lyz and c3) involved in innate immunity were up-regulated by HgCl2 exposure, suggesting that inorganic Hg had the potential to induce immunotoxicity. Taken together, the present study provides evidence that waterborne HgCl2 exposure can induce developmental impairment, oxidative stress and immunotoxicity in the early development stage of fish, which brings insights into the toxicity mechanisms of inorganic Hg in fish.

Reproductive toxicity of inorganic mercury exposure in adult zebrafish: Histological damage, oxidative stress, and alterations of sex hormone and gene expression in the hypothalamic-pituitary-gonadal axis.

Mercury (Hg) is a prominent environmental contaminant that causes a variety of adverse effects on aquatic organisms. However, the mechanisms underlying inorganic Hg-induced reproductive impairment in fish remains largely unknown. In this study, adult zebrafish were exposed to 0 (control), 15 and 30µg Hg/l (added as mercuric chloride, HgCl2) for 30days, and the effects on histological structure, antioxidant status and sex hormone levels in the ovary and testis, as well as the mRNA expression of genes involved in the hypothalamic-pituitary-gonadal (HPG) axis were analyzed. Exposure to Hg caused pathological lesions in zebrafish gonads, and changed the activities and mRNA levels of antioxidant enzymes (catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx)) as well as the content of glutathione (GSH) and malondialdehyde (MDA). In females, although ovarian 17ß-estradiol (E2) content remained relatively stable, significant down-regulation of lhß, gnrh2, gnrh3, lhr and erα were observed. In males, testosterone (T) levels in the testis significantly decreased after Hg exposure, accompanied by down-regulated expression of gnrh2, gnrh3, fshß and lhß in the brain as well as fshr, lhr, ar, cyp17 and cyp11b in the testis. Thus, our study indicated that waterborne inorganic Hg exposure caused histological damage and oxidative stress in the gonads of zebrafish, and altered sex hormone levels by disrupting the transcription of related HPG-axis genes, which could subsequently impair the reproduction of fish. Different response of the antioxidant defense system, sex hormone and HPG-axis genes between females and males exposed to inorganic Hg indicated the gender-specific regulatory effect by Hg. To our knowledge, this is the first time to explore the effects and mechanisms of inorganic Hg exposure on reproduction at the histological, enzymatic and molecular levels, which will greatly extend our understanding on the mechanisms underlying of reproductive toxicity of inorganic Hg in fish.

Contrasting effects of silicates on cadmium uptake by three dicotyledonous crops grown in contaminated soil.

The effects of several silicates (talcum powder (TP), calcium silicate (CS), sodium silicate (SS), and potassium silicate (PS)), in comparison with other amendments (quicklime (QL) and potassium dihydrogen phosphate (PDP)) on cadmium (Cd) uptake by three dicotyledonous crops (Amaranthus hypochondriacus L. Cv. 'K112', Amaranthus tricolor L., and Brassica oleracea var. albiflora Kuntze) were investigated in Cd-contaminated soil. The effects of both application methods of amendments (singly and combined) and timing of application were also evaluated. Sodium silicate was the most effective in reducing crop Cd uptake and translocation, which was diminished by 51% in roots, 53% in stems, and 72% in leaves on average. Application of CS amendment showed greater efficiency than PDP amendment in decreasing Cd uptake by crops and resulted in increased biomass. Potassium silicate only slightly decreased shoot Cd concentration. Combination of PDP and SS was able to overcome the inhibitory effect of SS on crop yield while decreasing Cd concentrations in roots, stems and leaves of the tested crops by average rates of 52, 65, and 68% respectively. Applications of SS and PS significantly reduced the root-to-shoot Cd transfer factor. We found that Si accumulation in crops was not associated with lower Cd concentration, indicating that Si in crops may play a major role in alleviating metal stress rather than inhibiting crop Cd accumulation. We suggested that the inhibitive effect of silicates on crops Cd uptake was majorly attributed to the properties of the silicates, those were their specific effects on soil pH and cations, which increased Cd adsorption by soil and suppressed Cd uptake from soil solution by increasing the relative dissolved concentrations of competing cations.

The mitogenome of Liobagrus marginatoides (Teleostei, Siluriformes:Amblycipitidae).

Liobagrus marginatoides is endemic to southwest China (Ding, 1994), according to morphological taxonomy, and it is very similar to Liobagrus nigricauda, but its population is much smaller. In this study, the complete mitochondrial genome sequence of L. Marginatoides has been obtained with polymerase chain reaction (PCR), which contains 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a non-coding control region with the total length of 16,498 bp. The gene arrangement and composition are similar to that of other vertebrates. Most of the genes are encoded on heavy strand, except for eight tRNA and ND6 genes. Just like most other vertebrates, the against bias of G has a universality in different statistics results. The complete mitochondrial genome sequence of L. Marginatoides would contribute to better understand population genetics and protect its genetic diversity.

The mitogenome of Liobagrus nigricauda (Teleostei, Siluriformes: Amblycipitidae).

Liobagrus nigricauda is endemic to the Yangtze River system (Ding 1994, The fishes of Sichuan province. pp. 470-78) and listed as an endangered species (IUCN 2012, Red list of threatened species. http://www.iucnredlist.org ). In this study, the complete mitochondrial genome sequence of L. nigricauda has been obtained with polymerase chain reaction (PCR), which contains 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a noncoding control region with the total length of 16,512 bp. The gene arrangement and composition are similar to that of other vertebrates. Most of the genes are encoded on heavy strand, except for eight tRNA and ND6 genes. Just like most other vertebrates, the bias against G has a universality in different statistics results. The mitogenome sequence of L. nigricauda would contribute to better understand population genetics and to protect its genetic diversity.

The complete mitochondrial genome of Liobagrus kingi (Teleostei, Siluriformes: Amblycipitidae).

Liobagrus kingi is endemic to southwest China and listed as endangered species (IUCN 2012). Genetic diversity is necessary for conservation issue. In studying this, the complete mitochondrial genome sequence of L. kingi has been obtained with PCR, which contains 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a non-coding control region with the total length of 16,483 bp. The gene arrangement and composition are similar to that of other vertebrates. Most of the genes are encoded on heavy strand, except for eight tRNA and ND6 genes. Just like most other vertebrates, the against bias of G has a universality in different statistical results. The complete mitochondrial genome sequence of L. kingi would contribute to better understand population genetics and protect its genetic diversity.