Organosulfur Materials for Rechargeable Batteries: Structure, Mechanism, and Application.

Lithium-ion batteries have received significant attention over the last decades due to the wide application of portable electronics and increasing deployment of electric vehicles. In order to further enhance the performance of the batteries and overcome the capacity limitations of inorganic electrode materials, it is imperative to explore new cathode and functional materials for rechargeable lithium batteries. Organosulfur materials containing sulfur-sulfur bonds as a kind of promising organic electrode materials have the advantages of high capacities, abundant resources, tunable structures, and environmental benignity. In addition, organosulfur materials have been widely used in almost every aspect of rechargeable batteries because of their multiple functionalities. This review aims to provide a comprehensive overview on the development of organosulfur materials including the synthesis and application as cathode materials, electrolyte additives, electrolytes, binders, active materials in lithium redox flow batteries, and other metal battery systems. We also give an in-depth analysis of structure-property-performance relationship of organosulfur materials, and guidance for the future development of organosulfur materials for next generation rechargeable lithium batteries and beyond.

Carbon disulfide: A redox mediator for organodisulfides in redox flow batteries.

Organodisulfides (RSSR) are a class of promising active materials for redox flow batteries (RFBs). However, their sluggish kinetics and poor cyclic stability remain a formidable challenge. Here, we propose carbon disulfide (CS2) as a unique redox mediator involving reversible C-S bond formation/breakage to facilitate the reduction reaction of organodisulfides in RFBs. In the discharge of RSSR, CS2 interacts with the negatively charged RSSR-• to promote cleavage of the S-S bond by reducing about one-third of the energy barrier, forming RSCS2Li. In the recharge, CS2 is unbonded from RSCS2Li while RSSR is regenerated. Meanwhile, the redox mediator can also be inserted into the molecular structure of RSSR to form RSCS2SR/RSCS2CS2SR, and these new active materials with lower energy barriers can further accelerate the reaction kinetics of RSSR. With CS2, phenyl disulfide exhibits an exceptional rate capability and cyclability of 500 cycles. An average energy efficiency of >90% is achieved. This strategy provides a unique redox-mediating pathway involving C-S bond formation/breakage with the active species, which is different from those used in lithium-oxygen or other batteries.

Mild Traumatic Brain Injury-Induced Augmented Postsurgical Pain Is Driven by Central Serotonergic Pain-Facilitatory Signaling.

BACKGROUND: Individuals recovering from mild traumatic brain injury (mTBI) have increased rates of acute and chronic pain. However, the mechanism through which mTBI triggers heightened pain responses and the link between mTBI and postsurgical pain remain elusive. Recent data suggest that dysregulated serotonergic pain-modulating circuits could be involved. We hypothesized that mTBI triggers dysfunction in descending serotonergic pain modulation, which exacerbates acute pain and delays pain-related recovery after surgery. METHODS: Using mouse models of mTBI and hindpaw incision for postsurgical pain in C57BL/6J mice, mechanical withdrawal thresholds were assessed throughout the postsurgical period. To determine whether mTBI leads to persistent alteration of endogenous opioid tone, mu-opioid receptors (MORs) were blocked with naloxone. Finally, the role of descending serotonergic signaling on postsurgical allodynia in animals with mTBI was examined using ondansetron (5-HT 3 receptor antagonist) or a serotonin-specific neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), to ablate descending serotonergic fibers. The treatment effects on withdrawal thresholds were normalized to baseline (percentage of maximum possible effect, MPE%), and analyzed using paired t -test or 2-way repeated-measures ANOVA with post hoc multiple comparisons. RESULTS: Post-mTBI mice demonstrated transient allodynia in hindpaws contralateral to mTBI, while no nociceptive changes were observed in sham-mTBI animals (mean difference, MD, MPE%, post-mTBI day 3: -60.9; 95% CI, -88.7 to -35.0; P < .001). After hindpaw incision, animals without mTBI exhibited transient allodynia, while mice with prior mTBI demonstrated prolonged postsurgical allodynia (MD-MPE% postsurgical day 14: -65.0; 95% CI, -125.4 to -4.5; P = .04). Blockade of MORs using naloxone transiently reinstated allodynia in mTBI animals but not in sham-mTBI mice (MD-MPE% post-naloxone: -69.9; 95% CI, -94.8 to -45.1; P < .001). Intrathecal administration of ondansetron reversed the allodynia observed post-mTBI and postincision in mTBI mice (compared to vehicle-treated mTBI mice, MD-MPE% post-mTBI day 3: 82.7; 95% CI, 58.5-106.9; P < .001; postsurgical day 17: 62.5; 95% CI, 38.3-86.7; P < .001). Both the acute allodynia after TBI and the period of prolonged allodynia after incision in mTBI mice were blocked by pretreatment with 5,7-DHT (compared to sham-mTBI mice, MD-MPE% post-mTBI day 3: 0.5; 95% CI, -18.5 to 19.5; P = .99; postsurgical day 14: -14.6; 95% CI, -16.7 to 45.9; P = .48). Similar behavioral patterns were observed in hindpaw ipsilateral to mTBI. CONCLUSIONS: Collectively, our results show that descending serotoninergic pain-facilitating signaling is responsible for nociceptive sensitization after mTBI and that central endogenous opioid tone opposes serotonin's effects. Understanding brain injury-related changes in endogenous pain modulation may lead to improved pain control for those with TBI undergoing surgery.

eDNA reveals spatial homogenization of fish diversity in a mountain river affected by a reservoir cascade.

One of the main reasons for the decline in global freshwater biodiversity can be attributed to alterations in hydrological conditions resulting from dam construction. However, the majority of current research has focused on single or limited numbers of dams. Here, we carried out a seasonal fish survey, using environmental DNA (eDNA) method, on the Wujiang River mainstream (Tributaries of the Yangtze River, China) to investigate the impact of large-scale cascade hydropower development on changes in fish diversity patterns. eDNA survey revealed that native fish species have decreased in contrast to alien fish. There was also a shift in fish community structure, with declines of the dominant rheophilic fish species, an increase of the small-size fish species, and homogenization of species composition across reservoirs. Additionally, environmental factors, such as temperature, dissolved oxygen and reservoir age, had a significant effect on fish community diversity. This study provides basic information for the evaluation of the impact of cascade developments on fish diversity patterns.

Diagnostic performance of a novel automated CT-derived FFR technology in detecting hemodynamically significant coronary artery stenoses: A multicenter trial in China.

BACKGROUND AND AIMS: Computed tomography-derived fractional flow reserve (CT-derived FFR) algorithms have emerged as promising noninvasive methods for identifying hemodynamically significant coronary artery disease (CAD). However, its broad adaption is limited by the complex workflow, slow processing, and supercomputer requirement. Therefore, CT-derived FFR solutions capable of producing fast and accurate results could help deliver time-sensitive results rapidly and potentially alter patient management. The current study aimed to determine the diagnostic performance of a novel CT-derived FFR algorithm, esFFR, on patients with CAD was evaluated. METHODS: 329 patients from 6 medical centers in China were included in this prospective study. CT-derived FFR calculations were performed on 350 vessels using the esFFR algorithm using patients' presenting coronary computed tomography angiography (CCTA) images, and results and processing speed were recorded. Using invasive FFR measurements from direct coronary angiography as the reference standard, the diagnostic performance of esFFR and CCTA in detecting hemodynamically significant lesions were compared. Post-hoc analyses were performed for patients with calcified lesions or stenoses within the CT-derived FFR diagnostic "gray zone." RESULTS: The esFFR values correlated well with invasive FFR. The sensitivity, specificity, accuracy, positive and negative predictive value for esFFR were all above 90%. The overall performance of esFFR was superior to CCTA. Coronary calcification had minimal effects on esFFR's diagnostic performance. It also maintained 85% of diagnostic accuracy for "gray zone" lesions, which historically was <50%. The average esFFR processing speed was 4.6 ± 1.3 minutes. CONCLUSIONS: The current study demonstrated esFFR had high diagnostic efficacy and fast processing speed in identifying hemodynamically significant CAD.

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.

Thiuram Monosulfide with Ultrahigh Redox Activity Triggered by Electrochemical Oxidation.

Organosulfides are promising cathodes for lithium batteries but often suffer from sluggish kinetics and low cycle stability. Herein, we report an electron-deficient organosulfide (ED-OS), which is formed via electrochemical oxidation of thiuram monosulfide, a low-cost sustainable material. The ED structure of (dimethylcarbamothioyl)thio can stretch the electron cloud of the adjacent C═S bond forming an S radical and lead to the cleavage of the S-C bond on the other side forming another S radical. The two (dimethylcarbamothioyl)thio radicals can form S-S bonds individually with low energy barriers, which thus are easy to break and could accommodate lithium ions with ultrafast reaction kinetics. It exhibits an ultralong cyclability of over 8000 cycles with a low capacity-fade rate of 0.0038% per cycle at a high rate of 10C in a lithium cell. In addition, we demonstrate that the same electrochemical oxidation can be applied to other thiuram compounds. This work provides new opportunities in developing ultrahigh-redox-activity organic electrode materials which can be started as needed.

Exploration of a Brain-Liver-Communication-Related Mechanism Involved in the Experimental Perimenopausal Depression Rat Model using Chaihu-Shugan-San.

Existing research suggests the involvement of a brain-liver-communication-related mechanism in the occurrence of depression. In this study, we selected Chaihu-Shugan-San (CSS), a traditional Chinese herbal medicine that can simultaneously affect liver and depression, as a probe to investigate the involvement of the brain-liver-communication-related mechanism in perimenopausal depression. A total of 50 experimental perimenopausal depression rat models were established by ovariectomy surgery (PMS) followed by chronic unpredictable mild stress (CUMS) processes. Animals underwent CSS treatment or treatments with CSS + Ly294002, an inhibitor of the PI3K/Akt signalling pathway. We observed the behavioural performances of depression and anxiety, serum concentrations of biochemical indices, serum estrogen two levels, hippocampal 5-HT and NE levels and the morphological changes in liver tissues. The protein and mRNA expressions of PI3K and Akt were also evaluated. CSS treatment significantly ameliorated the behavioural performance, partial biochemical indices and the morphological changes in the liver tissues of PMS + CUMS rats. Ly294002 partially inhibited the CSS effects. The expressions of PI3K and Akt were significantly downregulated by PMS + CUMS processes but upregulated by CSS treatment, which could be significantly suppressed by Ly294002. A brain-liver-communication-related mechanism may be involved in perimenopausal depression, where the PI3K/Akt signalling pathway plays a vital role.

The Molecular Basis and Pathophysiology of Trigeminal Neuralgia.

Trigeminal neuralgia (TN) is a complex orofacial pain syndrome characterized by the paroxysmal onset of pain attacks in the trigeminal distribution. The underlying mechanism for this debilitating condition is still not clearly understood. Decades of basic and clinical evidence support the demyelination hypothesis, where demyelination along the trigeminal afferent pathway is a major driver for TN pathogenesis and pathophysiology. Such pathological demyelination can be triggered by physical compression of the trigeminal ganglion or another primary demyelinating disease, such as multiple sclerosis. Further examination of TN patients and animal models has revealed significant molecular changes, channelopathies, and electrophysiological abnormalities in the affected trigeminal nerve. Interestingly, recent electrophysiological recordings and advanced functional neuroimaging data have shed new light on the global structural changes and the altered connectivity in the central pain-related circuits in TN patients. The current article aims to review the latest findings on the pathophysiology of TN and cross-examining them with the current surgical and pharmacologic management for TN patients. Understanding the underlying biology of TN could help scientists and clinicians to identify novel targets and improve treatments for this complex, debilitating disease.

Remodeling of Arctic char (Salvelinus alpinus) lipidome under a stimulated scenario of Arctic warming.

Arctic warming associated with global climate change poses a significant threat to populations of wildlife in the Arctic. Since lipids play a vital role in adaptation of organisms to variations in temperature, high-resolution mass-spectrometry-based lipidomics can provide insights into adaptive responses of organisms to a warmer environment in the Arctic and help to illustrate potential novel roles of lipids in the process of thermal adaption. In this study, we studied an ecologically and economically important species-Arctic char (Salvelinus alpinus)-with a detailed multi-tissue analysis of the lipidome in response to chronic shifts in temperature using a validated lipidomics workflow. In addition, dynamic alterations in the hepatic lipidome during the time course of shifts in temperature were also characterized. Our results showed that early life stages of Arctic char were more susceptible to variations in temperature. One-year-old Arctic char responded to chronic increases in temperature with coordinated regulation of lipids, including headgroup-specific remodeling of acyl chains in glycerophospholipids (GP) and extensive alterations in composition of lipids in membranes, such as less lyso-GPs, and more ether-GPs and sphingomyelin. Glycerolipids (e.g., triacylglycerol, TG) also participated in adaptive responses of the lipidome of Arctic char. Eight-week-old Arctic char exhibited rapid adaptive alterations of the hepatic lipidome to stepwise decreases in temperature while showing blunted responses to gradual increases in temperature, implying an inability to adapt rapidly to warmer environments. Three common phosphatidylethanolamines (PEs) (PE 36:6|PE 16:1_20:5, PE 38:7|PE 16:1_22:6, and PE 40:7|PE 18:1_22:6) were finally identified as candidate lipid biomarkers for temperature shifts via machine learning approach. Overall, this work provides additional information to a better understanding of underlying regulatory mechanisms of the lipidome of Arctic organisms in the face of near-future warming.

Life Cycle Exposure to Environmentally Relevant Concentrations of Diphenyl Phosphate (DPhP) Inhibits Growth and Energy Metabolism of Zebrafish in a Sex-Specific Manner.

Due to commercial uses and environmental degradation of aryl phosphate esters, diphenyl phosphate (DPhP) is frequently detected in environmental matrices and is thus of growing concern worldwide. However, information on potential adverse effects of chronic exposure to DPhP at environmentally realistic concentrations was lacking. Here, we investigated the effects of life cycle exposure to DPhP on zebrafish at environmentally relevant concentrations of 0.8, 3.9, or 35.6 µg/L and employed a dual-omics approach (metabolomics and transcriptomics) to characterize potential modes of action. Exposure to DPhP at 35.6 µg/L for 120 days resulted in significant reductions in body mass and length of male zebrafish, but did not cause those same effects to females. Predominant toxicological mechanisms, including inhibition of oxidative phosphorylation, down-regulation of fatty acid oxidation, and up-regulation of phosphatidylcholine degradation, were revealed by integrated dual-omics analysis and successfully linked to adverse outcomes. Activity of succinate dehydrogenase and protein content of carnitine O-palmitoyltransferase 1 were significantly decreased in livers of male fish exposed to DPhP, which further confirmed the proposed toxicological mechanisms. This study is the first to demonstrate that chronic, low-level exposure to DPhP can retard growth via inhibiting energy output in male zebrafish.

Efficacy and Safety of Awake Computed Tomography-Guided Percutaneous Balloon Compression of Trigeminal Ganglion for Trigeminal Neuralgia.

OBJECTIVES: To describe the method and clinical efficacy of awake computed tomography (CT)-guided percutaneous balloon compression (PBC) as a treatment for trigeminal neuralgia (TN). DESIGN: In this case series, patients with TN were treated with awake CT-guided PBC and followed up for treatment efficacy and complications for 12 months. SETTING: A single-center study. SUBJECTS: A total of 66 patients with medical treatment-refractory TN were recruited for the study. METHODS: The procedure was performed under moderate sedation. A balloon catheter was inserted through a trocar needle to reach Meckel's cavity under CT guidance. The position and optimal shape of the contrast-filled balloon were confirmed with CT three-dimensional reconstruction. Compression of the trigeminal ganglion was considered complete when the patient notified operators about facial hypoesthesia or the resolution of TN symptoms. All patients were followed up monthly for 12 months to monitor treatment efficacy and complications. RESULTS: The average trigeminal ganglion compression time was 272 ± 81 seconds, at which point the patients reported significant facial hypoesthesia compared with the contralateral side or resolution of triggered pain in the affected area. All patients had resolution of TN symptoms for 6 months, with a 1-year recurrence rate of 13%. The overall safety profile was improved with the technique described in this study. Side effects, such as hypoesthesia and mastication weakness, were overall mild and did not impact patients' quality of life. Some complications that historically have been associated with PBC, such as diplopia and keratitis, were not present. CONCLUSIONS: This new awake CT-guided PBC technique produces better outcomes than the traditional PBC under fluoroscopy guidance and general anesthesia.

Phylogenetic perspective on the relationships and evolutionary history of the Acipenseriformes.

The Acipenseriformes, as one of the earliest extant vertebrates, plays an important role in the evolution of fishes and even the whole vertebrates. Here we collected and analyzed all complete mitochondrial genomes of Acipenseriformes species. Phylogenetic analyses demonstrated that the polytomous branch included Acipenseridae and Polyodontidae formed five clades. The Polyodontidae clade and the Scaphirhynchus clade both were monophyletic group, whereas the Acipenser species and the Huso species both were polyphyletic group. The Bayesian divergence times showed that the origin time for Acipenseriformes was at 318.0 Mya, which was similar to the some previous results of 312.1 Mya, 346.9 Mya and 389.7 Mya. The result was in good consistent with the paleontological data available and the split time of the Pacific and Atlantic Oceans from the Jurassic to the Cretaceous (Laurasia splits in North America and Eurasia). The dN/dS ratios showed the evolutionary rates gradually slow down in five major Acipenseriformes clades from the Clade A (the Pacific sturgeons species) to Clade C (the genus Scaphirhynchus), which was related to the process of geographical formation.

Plasticity in the Link between Pain-Transmitting and Pain-Modulating Systems in Acute and Persistent Inflammation.

There is strong evidence that spinoparabrachial neurons in the superficial dorsal horn contribute to persistent pain states, and that the lateral parabrachial complex (PB) conveys relevant nociceptive information to higher structures. The role of PB itself in hyperalgesia and how it recruits descending facilitation has nevertheless received significantly less attention. The current study is a first step toward delineating the functional dynamics of PB and its link to descending control in acute and persistent inflammatory pain. In lightly anesthetized rats, we recorded behavioral withdrawal evoked by mechanical stimulation of the hindpaw and, simultaneously, the activity of identified pain-modulating neurons, "ON-cells" and "OFF-cells," in the rostral ventromedial medulla (RVM). This was done before and after the inactivation of PB, contralateral or ipsilateral to an inflamed paw [1 h, 1 d, or 5-6 d after intraplantar injection of Complete Freund's Adjuvant (CFA)]. The inactivation of contralateral, but not ipsilateral, PB interfered with nociceptive input to RVM under basal conditions, as well as in acute inflammation. By contrast, blocking ipsilateral, but not contralateral, PB in established inflammation interfered with behavioral hyperalgesia and ON-cell and OFF-cell responses. The lesioning of contralateral PB before CFA injection prevented this recruitment of ipsilateral PB in persistent inflammation. These experiments show that contralateral PB is required to initiate hyperalgesia, which is then maintained by ipsilateral PB, most likely in both cases via the engagement of pain-modulating neurons of the RVM.SIGNIFICANCE STATEMENT The lateral parabrachial complex (PB) relays nociceptive information to brain circuits that are important for the transmission and modulation of pain, but its specific role in persistent pain and engagement of descending control mechanisms has received relatively little attention. We show here that PB contralateral and ipsilateral to an inflammatory insult demonstrate different functions as inflammation persists, likely by engaging pain-facilitating neurons of the rostral ventromedial medulla. While the contralateral PB, the target of the major spinoparabrachial pathway, relays acute nociceptive information, the ipsilateral PB is recruited or unmasked in persistent inflammation to maintain hyperalgesia. These data point to plasticity in the PB itself or its direct and indirect connections with pain-modulating systems as central to the development and maintenance of persistent pain.

Role of fragile X mental retardation protein in chronic pain.

Chronic pain has detrimental effects on one's quality of life. However, its treatment options are very limited, and its underlying pathogenesis remains unclear. Recent research has suggested that fragile X mental retardation protein is involved in the development of chronic pain, making it a potential target for prevention and treatment. The current review of literature will examine the function of fragile X mental retardation protein and its associated pathways, through which we hope to gain insight into how fragile X mental retardation protein may contribute to nociceptive sensitization and chronic pain.

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.

Descending Control Mechanisms and Chronic Pain.

PURPOSE OF REVIEW: The goal of the review was to highlight recent advances in our understanding of descending pain-modulating systems and how these contribute to persistent pain states, with an emphasis on the current state of knowledge around "bottom-up" (sensory) and "top-down" (higher structures mediating cognitive and emotional processing) influences on pain-modulating circuits. RECENT FINDINGS: The connectivity, physiology, and function of these systems have been characterized extensively over the last 30 years. The field is now beginning to ask how and when these systems are engaged to modulate pain. A recent focus is on the parabrachial complex, now recognized as the major relay of nociceptive information to pain-modulating circuits, and plasticity in this circuit and its connections to the RVM is marked in persistent inflammatory pain. Top-down influences from higher structures, including hypothalamus, amygdala, and medial prefrontal areas, are also considered. The challenge will be to tease out mechanisms through which a particular behavioral context engages distinct circuits to enhance or suppress pain, and to understand how these mechanisms contribute to chronic pain.

Diethylstilbestrol impaired oogenesis of yellow catfish juveniles through disrupting hypothalamic-pituitary-gonadal axis and germ cell development.

Diethylstilbestrol (DES), a non-steroidal estrogen, has been found to cause altered germ cell development and disordered ovarian development in fish females. However, the mechanisms that might be involved are poorly understood. In this study, female juveniles of yellow catfish (Pelteobagrus fulvidraco) (120 days post-hatching) were exposed to two doses (10 and 100 ng l-1 ) of DES for 28 days. After the endpoint of exposure, decreased ovary weight and gonadosomatic index, as well as various ovarian impairments were observed in response to DES. Besides, DES elevated the mRNA levels of vitellogenin 1 (vtg 1) and estrogen receptor 1 (esr 1) in liver and decreased 17ß-estradiol level in plasma. Correspondingly, suppressed mRNA levels of the key genes in the hypothalamic-pituitary-gonadal axis (such as cyp19a1b, gnrh-II, fshß and lhß in brain and fshr, lhr and cyp19a1a in ovary) after DES exposure were also observed. The declined level of plasma 17ß-estradiol and altered gene expressions of genes in the hypothalamic-pituitary-gonadal axis were thus supposed to be closely related to the disrupted oogenesis in DES-treated fish. Analyses further demonstrated that, higher concentration of DES elevated the expression ratio of bax/bcl-2, indicating the enhanced apoptosis occurred in ovary. Moreover, DES upregulated the expressions of genes involved in proliferation (cyclin d1 and pcna), meiotic entry (cyp26a1 and scp3) and meiotic maintenance (dmc1), resulting in arrested oogenesis in catfish. The present study greatly extended our understanding on the mechanisms underlying of reproductive toxicity of DES on fish oogenesis.

Effects of inorganic mercury exposure on histological structure, antioxidant status and immune response of immune organs in yellow catfish (Pelteobagrus fulvidraco).

Mercury (Hg) is well recognized as a highly toxic substance to fish. Nevertheless, little is known about the toxic effects of Hg on immune organs. In this study, we investigated histology, antioxidant status and immune response of the spleen and head kidney in yellow catfish following 6 weeks of exposure to environmentally relevant concentrations of inorganic Hg (2 and 10 µg l-1 Hg2+ ). As expected, Hg accumulation and histological injury in both tissues were observed. Meanwhile, Hg2+ exposure induced oxidative stress, which increased antioxidant enzyme (superoxide dismutase, catalase and glutathione peroxidase) activities, glutathione content, anti-hydroxyl radical capacity and the expression of genes associated with antioxidant (sod1, cat, gpx1, nrf2 and mt) and stress (hsp70) responses in dose- and tissue-specific manners. In the spleen, the mRNA levels of immune-related genes (il-1ß, il-8, tnf-α, il-10, tgf-ß, lys and c3) were upregulated by Hg2+ exposure. However, in the head kidney, upregulation of tnf-α, il-10 and tgf-ß mRNAs and downregulation of il-1ß and lys expressions were observed, while transcriptions of il-8 and c3 were remarkably upregulated only in the 2 µg l-1 group. Overall, our study indicated that Hg2+ exposure could result in Hg accumulation and thereby induced histological impairment, oxidative stress and immunotoxicity in immune organs of yellow catfish, but some enzymes and/or genes involved in antioxidant and immune systems would be activated to resist Hg2+ -induced damage.