Excessive immunosuppression by regulatory T cells antagonizes T cell response to schistosome infection in PD-1-deficient mice.

Schistosomiasis is caused by parasitic flatworms known as schistosomes and affects over 200 million people worldwide. Prevention of T cell exhaustion by blockade of PD-1 results in clinical benefits to cancer patients and clearance of viral infections, however it remains largely unknown whether loss of PD-1 could prevent or cure schistosomiasis in susceptible mice. In this study, we found that S. japonicum infection dramatically induced PD-1 expression in T cells of the liver where the parasites chronically inhabit and elicit deadly inflammation. Even in mice infected by non-egg-producing unisex parasites, we still observed potent induction of PD-1 in liver T cells of C57BL/6 mice following S. japonicum infection. To determine the function of PD-1 in schistosomiasis, we generated PD-1-deficient mice by CRISPR/Cas9 and found that loss of PD-1 markedly increased T cell count in the liver and spleen of infected mice. IL-4 secreting Th2 cells were significantly decreased in the infected PD-1-deficient mice whereas IFN-γ secreting CD4+ and CD8+ T cells were markedly increased. Surprisingly, such beneficial changes of T cell response did not result in eradication of parasites or in lowering the pathogen burden. In further experiments, we found that loss of PD-1 resulted in both beneficial T cell responses and amplification of regulatory T cells that prevented PD-1-deficient T cells from unleashing anti-parasite activity. Moreover, such PD-1-deficient Tregs exert excessive immunosuppression and express larger amounts of adenosine receptors CD39 and CD73 that are crucial for Treg-mediated immunosuppression. Our experimental results have elucidated the function of PD-1 in schistosomiasis and provide novel insights into prevention and treatment of schistosomiasis on the basis of modulating host adaptive immunity.

One-step sintering construction of electromagnetic synergistic Co7Fe3/Co@CBC nanocomposites for enhanced microwave absorption properties.

Based on the synergistic modulation of electromagnetic parameters and microstructure design, multidimensional porous magnetic carbon-based nanocomposites have become ideal materials with efficient absorption properties. What's more, a carbon-magnetic alloy composite is a commonly used and efficient microwave absorber. In this paper, Co7Fe3/Co@CBC (CFCC) nanocomposites with strong magnetism, a three-phase composition, and a three-dimensional porous structure were synthesized by reducing Fe2+ and Co2+ using chestnut-shell biomass carbon (CBC). Biomass carbon with a higher specific surface area provides numerous active sites for Co7Fe3 nanosheets and Co nanospheres to form three-dimensional ping-pong chrysanthemum-like nanocomposites, which generate rich heterogeneous interfaces and conductive network structures. By adjusting the amount of added biomass, the electromagnetic parameters can be effectively regulated to achieve efficient microwave absorption properties. When the amount of biomass added varies within the range of 1.0 to 2.5 g, all samples exhibit a favorable effective absorption bandwidth (EAB) of over 5.88 GHz. In particular, the CFCC-2.0 composite exhibits optimal microwave absorption properties, with a minimum reflection loss (RLmin) value of -59.25 dB and an EAB of 6.34 GHz at a thickness of 2.8 mm. The simulation and modeling analysis results of radar cross section (RCS) further confirm the exceptional attenuation capability of composite materials at multiple incident angles. The exceptional microwave absorption properties and stability of EAB for the Co7Fe3/Co@CBC nanocomposite make it a promising candidate in the field of absorbing materials. This work also provides some feasible ideas for designing stable broadband wave-absorbing materials.

PRMT1 inhibition promotes ferroptosis sensitivity via ACSL1 upregulation in acute myeloid leukemia.

Acute myeloid leukemia (AML) is a hematological malignancy with an alarming mortality rate. The development of novel therapeutic targets or drugs for AML is urgently needed. Ferroptosis is a form of regulated cell death driven by iron-dependent lipid peroxidation. Recently, ferroptosis has emerged as a novel method for targeting cancer, including AML. Epigenetic dysregulation is a hallmark of AML, and a growing body of evidence suggests that ferroptosis is subject to epigenetic regulation. Here, we identified protein arginine methyltransferase 1 (PRMT1) as a ferroptosis regulator in AML. The type I PRMT inhibitor GSK3368715 promoted ferroptosis sensitivity in vitro and in vivo. Moreover, PRMT1-knockout cells exhibited significantly increased sensitivity to ferroptosis, suggesting that PRMT1 is the primary target of GSK3368715 in AML. Mechanistically, both GSK3368715 and PRMT1 knockout upregulated acyl-CoA synthetase long-chain family member 1 (ACSL1), which acts as a ferroptosis promoter by increasing lipid peroxidation. Knockout ACSL1 reduced the ferroptosis sensitivity of AML cells following GSK3368715 treatment. Additionally, the GSK3368715 treatment reduced the abundance of H4R3me2a, the main histone methylation modification mediated by PRMT1, in both genome-wide and ACSL1 promoter regions. Overall, our results demonstrated a previously unknown role of the PRMT1/ACSL1 axis in ferroptosis and suggested the potential value and applications of the combination of PRMT1 inhibitor and ferroptosis inducers in AML treatment.

Acteoside protects podocyte against apoptosis through regulating AKT/GSK-3ß signaling pathway in db/db mice.

BACKGROUND: Podocyte apoptosis is one of the important pathological mechanisms of diabetic kidney disease (DKD). Acteoside (Act), a major active component of Rehmannia glutinosa leaves total glycoside, has a strong renoprotective action. Our study aims to demonstrate Act's renoprotective actions in db/db mice. METHODS: We adopted C57BLKS/J db/db mice as DKD animal models. After 8 weeks of Act administration, the 24-hour urine albumin, renal function index, and blood lipid levels were quantified using matching kits. Renal pathology was evaluated by HE and PAS staining. The podocyte damage and apoptosis-related signaling pathway were observed by using immunohistochemistry, western blot, and TUNEL staining. RESULTS: The albuminuria of db/db mice was reduced from 391 ug/24 h to 152 ug/24 h, and renal pathology changes were alleviated after Act administration. The western blot and immunohistochemistry showed that Act treatment upregulated the synaptopodin and podocin expression compared with db/db mice, while the TUNEL staining indicated podocyte apoptosis was inhibited. The B-cell lymphoma-2 (Bcl-2) level was upregulated in the Act group, but cleaved caspase-3 and Bcl-2 associated X protein (Bax) expression declined, while the protein kinase B/glycogen synthase kinase-3ß (AKT/GSK-3ß) signaling pathway was repressed. CONCLUSIONS: By inhibiting the AKT/GSK-3ß signaling pathway, Act protected podocytes from apoptosis, decreasing the urine albumin of db/db mice and delaying the course of DKD.

Alternating chimera states in complex networks with modular structures.

Chimera, the coexistence state of synchronization and non-synchronization, widely exists in complex networks. It has a great potentially explanatory power for the unihemispheric sleep of birds and some mammals, in which the synchronizations of the hemispheres of the cerebral cortex are evolving alternately. In this study, a coupled nonlinear oscillator system with a topology of the modular complex network was constructed to simulate the left and right hemispheres of the brain. The results showed that a stable chimera, an alternating chimera, and a breathing chimera were produced when the coupling strength and connection probability of the left and right hemispheres were changed. Further, we studied the effect of noise on rich synchronous patterns and found that the alternating chimera was robust to Gaussian white noise when the strength was not very large. Finally, our study was extended to a complex network with three sub-networks, and an alternating chimera could exist in two or three sub-networks. Our research provides a deeper insight into the mechanism of brain function like unihemispheric sleep.

Network modeling-based identification of the switching targets between pyroptosis and secondary pyroptosis.

The newly identified cell death type, pyroptosis plays crucial roles in various diseases. Most recently, mounting evidence accumulates that pyroptotic signaling is highly correlated with coronavirus disease 2019 (COVID-19). Thus, understanding the induction of the pyroptotic signaling and dissecting the detail molecular control mechanisms are urgently needed. Based on recent experimental studies, a core regulatory model of the pyroptotic signaling is constructed to investigate the intricate crosstalk dynamics between the two cell death types, i.e., pyroptosis and secondary pyroptosis. The model well reproduces the experimental observations under different conditions. Sensitivity analysis determines that only the expression level of caspase-1 or GSDMD has the potential to individually change death modes. The decrease of caspase-1 or GSDMD level switches cell death from pyroptosis to secondary pyroptosis. Besides, eight biochemical reactions are identified that can efficiently switch death modes. While from the viewpoint of bifurcation analysis, the expression level of caspase-3 is further identified and twelve biochemical reactions are obtained. The coexistence of pyroptosis and secondary pyroptosis is predicted to be observed not only within the bistable range, but also within proper monostable range, presenting two potential different control mechanisms. Combined with the landscape theory, we further explore the stochastic dynamic and global stability of the pyroptotic system, accurately quantifying how each component mediates the individual occurrence probability of pyroptosis and secondary pyroptosis. Overall, this study sheds new light on the intricate crosstalk of the pyroptotic signaling and uncovers the regulatory mechanisms of various stable state transitions, providing potential clues to guide the development for prevention and treatment of pyroptosis-related diseases.

Tristability in mitochondrial permeability transition pore opening.

Mitochondrial permeability transition pore (PTP), a key regulator of cell life and death processes, is triggered by calcium ions (Ca2+) and potentiated by reactive oxygen species (ROS). Although the two modes of PTP opening, i.e., transient and persistent, have been identified for a long time, its dynamical mechanism is still not fully understood. To test a proposed hypothesis that PTP opening acts as a tristable switch, which is characterized by low, medium, and high open probability, we develop a three-variable model that focused on PTP opening caused by Ca2+ and ROS. For the system reduced to two differential equations for Ca2+ and ROS, both the stability analysis and the potential landscape feature that it exhibits tristability under standard parameters. For the full system, the bifurcation analysis suggests that it can achieve tristability over a wide range of input parameters. Furthermore, parameter sensitivity analysis demonstrates that the existence of tristability is a robust property. In addition, we show how the deterministic tristable property can be understood within a stochastic framework, which also explains the PTP dynamics at the level of a single channel. Overall, this study may yield valuable insights into the intricate regulatory mechanism of PTP opening.

Cell death modes are specified by the crosstalk dynamics within pyroptotic and apoptotic signaling.

The crosstalk between pyroptosis and apoptosis pathways plays crucial roles in homeostasis, cancer, and other pathologies. However, its molecular regulatory mechanisms for cell death decision-making remain to be elucidated. Based on the recent experimental studies, we developed a core regulatory network model of the crosstalk between pyroptosis and apoptosis pathways. Sensitivity analysis and bifurcation analysis were performed to assess the death mode switching of the network. Both the approaches determined that only the level of caspase-1 or gasdermin D (GSDMD) has the potential to individually change death modes. The decrease of caspase-1 or GSDMD switches cell death from pyroptosis to apoptosis. Seven biochemical reactions among the 21 reactions in total that are essential for determining cell death modes are identified by using sensitivity analysis. While with bifurcation analysis of state transitions, nine reactions are suggested to be able to efficiently switch death modes. Monostability, bistability, and tristability are observed under different conditions. We found that only the reaction that caspase-1 activation induced by stimuli can trigger tristability. Six and two of the nine reactions are identified to be able to induce bistability and monostability, respectively. Moreover, the concurrence of pyroptosis and apoptosis is observed not only within proper bistable ranges, but also within tristable ranges, implying two potentially distinct regulatory mechanisms. Taken together, this work sheds new light on the crosstalk between pyroptosis and apoptosis and uncovers the regulatory mechanisms of various stable state transitions, which play important roles for the development of potential control strategies for disease prevention and treatment.

On the Formation Mechanism of Column Damage Within Modular Taper Junctions.

BACKGROUND: Column damage is a unique degradation pattern observed in cobalt-chromium-molybdenum (CoCrMo) femoral head taper surfaces that resemble column-like troughs in the proximal-distal direction. We investigate the metallurgical origin of this phenomenon. METHODS: Thirty-two severely damaged CoCrMo femoral head retrievals from 7 different manufacturers were investigated for the presence of column damage and chemical inhomogeneities within the alloy microstructure via metallographic evaluation of samples sectioned off from the femoral heads. RESULTS: Column damage was found to affect 37.5% of the CoCrMo femoral heads in this study. All the column-damaged femoral heads exhibited chemical inhomogeneities within their microstructures, which comprised of regions enriched or depleted in molybdenum and chromium. Column damage appears as a dissolution of the entire surface with preferential corrosion along the molybdenum and chromium depleted regions. CONCLUSION: Molybdenum and chromium depleted zones serve as initiation sites for in vivo corrosion of the taper surface. Through crevice corrosion, the degradation spreads to the adjacent non-compositionally depleted areas of the alloy as well. Future improved alloy and processing recipes are required to ensure no chemical inhomogeneity due to segregation of solute elements are present in CoCrMo femoral heads.

Diagnostic value of 2017 ACR Thyroid Imaging Reporting and Data System (TI-RADS) combined with fine needle aspiration biopsy in thyroid nodules.

OBJECTIVE: To evaluate diagnostic value of Thyroid Imaging Reporting and Data System published by American College of Radiology (ACR TI-RADS) in 2017, ultrasound-guided fine-needle aspiration (US-FNA), and the combination of both methods in differentiation between benign and malignant thyroid nodules. METHODS: The data of US-FNA and ACR TI-RADS are collected from 159 patients underwent thyroid surgery in our hospital, which include a total of 178 thyroid nodules. A Bethesda System for Reporting Thyroid Cytopathology category of ≥IV and an ACR TI-RADS category ≥4 are regarded as diagnosis standards for malignancy in US-FNA and ACR TI-RADS, respectively. The pathological results after surgery are considered as the gold standard. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of the ACR TI-RADS, US-FNA and the combination of both methods for the differential diagnosis of thyroid nodules are calculated, respectively. RESULTS: The sensitivity, specificity and accuracy of ACR TI-RADS are 85.4%, 37.5%and 72.5%, respectively. The sensitivity, specificity and accuracy of US-FNA are 70.0%, 100%and 78.1%, respectively. After combining these two methods, the sensitivity, specificity and accuracy increase to 99.23%, 37.50%and 82.58%, respectively. The sensitivity of ACR TI-RADS is higher than that of US-FAN, and the sensitivity of combining these two methods is also higher than that of using ACR TI-RADS and US-FNA alone. CONCLUSION: The established ACR TI-RADS can help in selecting the target during nodule puncture, while the combination of ACR TI-RADS and US-FAN can further improve diagnostic ability for detecting malignant thyroid nodules.

Giant Mesenteric Mixed Hemangioma Misdiagnosed as Ovarian Cyst: A Case Report and a Literature Review.

Hemangiomas are congenital vascular disorders that occur primarily in the face and neck, extremely rare in the mesentery. Here, we report a rare small mesenteric mixed hemangioma. A 34-year-old woman was admitted to the gynecology department for an extended menstrual cycle. A cystic multi-atrial mass at the right anterior of uterus was observed by ultrasound examination, which was about 12.5 × 9.5 × 14.9 cm in size. The gynecologist mostly considered the possibility of the ovarian cyst. However, there was a huge multi-atrial cyst in the small intestine mesentery without the right ovarian cyst in the surgical exploration. The grape-like cystic mass about 15 cm in diameter adhered to the mesenteric root of the small intestine. The cyst was diagnosed as the mesenteric mixed hemangioma in the final histopathology.

Forkhead Box M1 Transcriptionally Regulates the Expression of Long Noncoding RNAs Snhg8 and Gm26917 to Promote Proliferation and Survival of Muscle Satellite Cells.

Multiple functions have been proposed for transcription factor FoxM1, including the regulation of cell proliferation, differentiation, senescence, apoptosis, and tissue homeostasis. However, the role of FoxM1 in muscle satellite cells (SCs) remains unclear. In the present study, we demonstrated that FoxM1 was essential for the proliferation and survival of SCs. Crucially, we found that long noncoding RNAs (lncRNAs) Snhg8 and Gm26917 significantly regulated the proliferation and apoptosis of SCs, respectively, and these lncRNAs were directly regulated by FoxM1 in SCs. Mechanistically, Snhg8 sustained SCs proliferation by promoting the transcription of ribosomal proteins, while Gm26917 acted as a competing endogenous RNA for microRNA-29b, which accelerated apoptosis of SCs. In mice, conditional knockout of FoxM1 in skeletal muscle resulted in decreased proliferation and increased apoptosis of SCs. Thus, our studies revealed a previously unrecognized role of FoxM1 in SCs and uncovered two lncRNAs, Snhg8 and Gm26917, which function as novel targets of FoxM1 in the regulation of SCs proliferation and survival. Stem Cells 2018;36:1097-1108.

CRISPR/Cas9-induced disruption of wt1a and wt1b reveals their different roles in kidney and gonad development in Nile tilapia.

Wilms tumor 1 (Wt1) is an essential factor for urogenital system development. Teleosts have two wt1s, named as wt1a and wt1b. In this study, the expression pattern of wt1a and wt1b and their functions on the urogenital system were analyzed by in situ hybridization and CRISPR/Cas9. wt1a was found to be expressed in the glomerulus at 3 dah (days after hatching), earlier than wt1b. wt1a and wt1b were simultaneously expressed in the somatic cells of gonads at 3 dah, while their cell locations were similar, but not identical in adult fish gonads. The wt1a-/- fish displayed pericardial edema and yolk sac edema at 3 dah and subsequently expanded as general body edema at 6 dah, failed to develop glomerulus and died during 6-10 dah, whereas the wt1b-/- fish were phenotypically normal. Immunohistochemical analyses revealed that the germ cell marker Vasa was expressed, while somatic cell genes Cyp19a1a, Amh, Gsdf and Dmrt1 were not expressed in the wt1a-/- gonads at 6 dah. The sex phenotypes of XX and XY in the wt1b-/- fish were not affected. Real-time PCR revealed that the ovarian cyp19a1a expression was up-regulated in XX wt1b-/- fish, compared with XX control at 90 dah. Serum estradiol-17ß level was also up-regulated in XX wt1b-/- fish at 90 and 180 dah. The XY wt1b-/- fish had normal serum estradiol-17ß and 11-ketotestosterone levels and remained fertile. These results suggest that Wt1a and Wt1b have different functions in the kidneys and gonads of tilapia.

Total Synthesis and Structure Revision of Palmarumycin B6.

Palmarumycin B6 and its regioisomer were synthesized via 7- and 13-step routes using 2-chlorophenol and 4-chlorophenyl methyl ether as the starting materials in overall yields of 2.7% and 12%, respectively. Their structures were characterized by 1H and 13C NMR, HRESIMS, and X-ray diffraction data. The structure of palmarumycin B6 was revised as 6-chloropalmarumycin CP17. The bioassay results showed that the larvicidal activity of palmarumycin B6 with an LC50 value of 32.7 µM was significantly higher than that of its 8-chloro isomer, with an LC50 value of 227.3 µM.

Identification and Evolution of TGF-ß Signaling Pathway Members in Twenty-Four Animal Species and Expression in Tilapia.

Transforming growth factor ß (TGF-ß) signaling controls diverse cellular processes during embryogenesis as well as in mature tissues of multicellular animals. Here we carried out a comprehensive analysis of TGF-ß pathway members in 24 representative animal species. The appearance of the TGF-ß pathway was intrinsically linked to the emergence of metazoan. The total number of TGF-ß ligands, receptors, and smads changed slightly in all invertebrates and jawless vertebrates analyzed. In contrast, expansion of the pathway members, especially ligands, was observed in jawed vertebrates most likely due to the second round of whole genome duplication (2R) and additional rounds in teleosts. Duplications of TGFB2, TGFBR2, ACVR1, SMAD4 and SMAD6, which were resulted from 2R, were first isolated. Type II receptors may be originated from the ACVR2-like ancestor. Interestingly, AMHR2 was not identified in Chimaeriformes and Cypriniformes even though they had the ligand AMH. Based on transcriptome data, TGF-ß ligands exhibited a tissue-specific expression especially in the heart and gonads. However, most receptors and smads were expressed in multiple tissues indicating they were shared by different ligands. Spatial and temporal expression profiles of 8 genes in gonads of different developmental stages provided a fundamental clue for understanding their important roles in sex determination and reproduction. Taken together, our findings provided a global insight into the phylogeny and expression patterns of the TGF-ß pathway genes, and hence contribute to the greater understanding of their biological roles in the organism especially in teleosts.

Bioinformatic analyses of zona pellucida genes in vertebrates and their expression in Nile tilapia.

Zona pellucida (ZP) genes encode ZP glycoproteins which constitute the coat surrounding oocytes and early embryos. Genome-wide identification of ZP genes is still lacking in vertebrates, especially in fish species. Herein, we conducted bioinformatic analyses of the ZP genes of the Nile tilapia and other vertebrates. Totally 16, 9, 17, 27, 21, 20, 26, 19, 14,11, 24, 17, 9, 18, 8, 11, 9, 8, 5, and 4 ZP genes belonging to 5 subfamilies (ZPA, ZPB, ZPC, ZPD, and ZPAX) were found in the sea lamprey, elephant shark, coelacanth, spotted gar, zebrafish, medaka, stickleback, Nile tilapia, Amazon molly, platyfish, seahorse, Northern snakehead, cavefish, tetraodon, clawed frog, turtle, chicken, platypus, kangaroo rat, and human genomes, respectively. The expansion of ZP genes in basal vertebrates was mainly achieved by gene duplication of ZPB, ZPC, and ZPAX subfamilies, while the shrink of ZP gene number in viviparous mammals was achieved by keeping only one copy of the ZP genes in each subfamily or even secondary loss of some subfamilies. The number of ZP gene is related to the environment where the eggs are fertilized and the embryos develop in vertebrates. Transcriptomic analysis showed that 14 ZP genes were expressed in the ovary of Nile tilapia, while two (ZPB2b and ZPC2) were highly expressed in the liver. On the other hand, ZPB1a and ZPB2c were not found to be expressed in any tissue or at any developmental stage of the gonads examined. In the ovary, the expression of ZP genes started from 30 dah (days after hatching), significantly upregulated at 90 dah and maintained this level at 180 dah. The expression of ZPC2 in the liver and ZPC5-2 and ZPAX1 in the ovary was confirmed by in situ hybridization. The ovary- and liver-expressed ZP genes are expressed coordinately with oocyte growth in tilapia.

Superconductivity above 100 K in single-layer FeSe films on doped SrTiO3.

Recent experiments on FeSe films grown on SrTiO3 (STO) suggest that interface effects can be used as a means to reach superconducting critical temperatures (Tc) of up to 80 K (ref. ). This is nearly ten times the Tc of bulk FeSe and higher than the record value of 56 K for known bulk Fe-based superconductors. Together with recent studies of superconductivity at oxide heterostructure interfaces, these results rekindle the long-standing idea that electron pairing at interfaces between two different materials can be tailored to achieve high-temperature superconductivity. Subsequent angle-resolved photoemission spectroscopy measurements of the FeSe/STO system revealed an electronic structure distinct from bulk FeSe (refs , ), with an energy gap vanishing at around 65 K. However, ex situ electrical transport measurements have so far detected zero resistance-the key experimental signature of superconductivity-only below 30 K. Here, we report the observation of superconductivity with Tc above 100 K in the FeSe/STO system by means of in situ four-point probe electrical transport measurements. This finding confirms FeSe/STO as an ideal material for studying high-Tc superconductivity.

Retinoic acid triggers meiosis initiation via stra8-dependent pathway in Southern catfish, Silurus meridionalis.

Existing studies demonstrated that retinoic acid (RA) regulates meiotic initiation via stra8-independent pathway in teleosts which lack stra8 in their genomes. However, stra8 was recently identified from several fish species including Southern catfish (Silurus meridionalis). To explore the existence of stra8-dependent pathway in RA mediated meiotic initiation in fishes, in the present study, the genes encoding RA synthase aldh1a2 and catabolic enzyme cyp26a1 and cyp26b1 were cloned from the Southern catfish. By immunohistochemistry, Aldh1a2 signal was observed in gonads of both sexes during the meiotic initiation period. By real-time PCR, differentially expressed gene was observed for cyp26a1, but not for cyp26b1, in gonads during the meiotic initiation. Administration of exogenous RA or inhibition of endogenous RA degradation by either KET (RA catabolic enzyme inhibitor) or cyp26a1 knockdown using CRISPR/Cas9 induced advanced meiotic initiation in the ovaries as demonstrated by increased Stra8/stra8 expression and appearance of oocytes. In contrast, treatment with RA synthase inhibitor DEAB resulted in delayed meiotic initiation and Stra8/stra8 expression in the ovaries, which was rescued by exogenous RA administration. These results indicated that (1) RA triggers the onset of meiosis via stra8-dependent pathway in stra8 existing teleosts, as it does in tetrapods; (2) exogenous RA can rescue the endogenous RA deficiency; (3) Cyp26a1, instead of Cyp26b1, is the key catabolic enzyme involved in meiosis initiation in teleosts. Taken together, RA might trigger meiotic initiation via stra8-dependent and -independent pathway in different teleosts.

Insecticidal Potential of Clove Essential Oil and Its Constituents on Cacopsylla chinensis (Hemiptera: Psyllidae) in Laboratory and Field.

Cacopsylla chinensis (Yang and Li) (Hemiptera: Psyllidae) is an important pest of pear in China. As an alternative to conventional chemical pesticides, botanicals including essential oils and their constituents could provide an eco-friendly and nonhazardous control method. In this study, the essential oil of clove buds (Syzygium aromaticum) was obtained by hydrodistillation. Five constituents, accounting for 99.89% of the oil, were identified by gas chromatography-mass spectrometry, and the major constituents were eugenol (88.61%) and eugenol acetate (8.89%), followed by ß-caryophyllene (1.89%). In a laboratory bioassay, clove essential oil, commercial eugenol (99.00%) and ß-caryophyllene (98.00%) exhibited strong contact toxicity against the summerform adults of C. chinensis with LD50 values of 0.730, 0.673, and 0.708 µg/adult, and against the nymphs with LD50 values of 1.795, 1.668, and 1.770 µg/nymph, respectively. In contrast, commercial eugenol acetate (98%) had LD50 values of 9.266 µg/adult and 9.942 µg/nymph. In a field trial, clove essential oil caused significant population reductions of 73.01% (4.80 mg/ml), 66.18% (2.40 mg/ml) and 46.56% (1.20 mg/ml), respectively. Our results demonstrated that clove essential oil and its constituents have potential as a source of natural insecticides.