Membrane progesterone receptor γ (paqr5b) is essential for the formation of neurons in the zebrafish olfactory rosette.

Paqr5b is a gene encoding membrane progesterone receptor γ (mPRγ), which is one of five mPR subtypes. Paqr5b belongs to the progestin and adipoQ receptor (PAQR) family, which consists of 11 genes. To elucidate the physiological functions of the mPR subtypes, we established gene knockout (KO) zebrafish strains by genetically editing seven paqr genes and analyzed their phenotypes. The null-mutant strain of paqr5b (paqr5b-/-) that we established in this study showed low fecundity, reduced chorion elevation and a high percentage of abnormal embryos. Embryos showed curvature of the spine and an abnormal head morphology. Individuals with abnormal head morphology continued to develop a phenotype of markedly abnormal palatine bone. The length of the brain of paqr5b-/- zebrafish was short, and the position of the cerebellum moved to the front and overlapped with that of the midbrain. Micro-CT scans revealed that the olfactory rosettes (ORs) were so shrunken that they were difficult to identify and connected with the olfactory bulbs (OBs) by thread-like structures. Immunohistochemical staining of OR with an anti-Paqr5b antibody revealed that Paqr5b was extensively expressed in neurons in the OR in wild-type zebrafish, whereas signals were not detected in paqr5b-/- zebrafish. In histological sections, the neurons disappeared, and the lamellar layer of the OR became thinner. These results indicate that Paqr5b is required for the formation of neurons in the OR. This is the first report demonstrating a distinct role for the mPR gene.

Physicochemical characterization and determination of trace metals in different edible fats and oils in Bangladesh: Nexus to human health.

The study assessed the quality of four different edible fats and oils using standard analytical techniques. The presence of potentially toxic elements was determined using atomic absorption spectrometry. This study reveals that edible oils function admirably in terms of physical traits such as moisture content, boiling point, melting point, density, and specific gravity. Some edible fats and oils exceeded the standard limit of moisture, acid value, and peroxide value and these values were found in the range of 0.120-0.760 %, 0.220-2.45 mg KOH/g, and 1.23-21.7 meq/kg respectively. The iodine value for fats showed satisfactory results but for oils observed lower than the standard value varied from 68.2 to 104 g/100 g. The results of saponification value for most of the oils and fats were found satisfactory but others were lower than recommended limits and detected results were in the range of 167-224 mg KOH/g. Trace metals viz. Fe, Mn, Ni, Pb, Cd, Cu, and Co were measured in all samples and the concentration ranged from 0.070 to 47.0, 0.120-2.44, 0.540-27.1, 0.030-1.87, 0.010-4.63 and 0.060-8.39 ppm for iron, manganese, nickel, lead, copper, and cobalt respectively. The study found high levels of Fe, Mn, Ni, Cu, and Co in edible fats and oils in Bangladesh. No Cd was found, and Pb was not present in over half of the samples, which included the majority of mustard oils. The levels of Fe and Ni were higher than advised, but there was no discernible toxicological danger from Cd or Pb. The results of the health risk assessment indicated that there was no risk to children's health and possible hazards to adults' health.

Improving the thermal performance of vertical ground heat exchanger by modifying spiral tube geometry: A numerical study.

Ground heat exchanger (GHE) is the most crucial element of a ground source heat pump (GSHP) system for building cooling and heating by the utilization of geothermal energy. Therefore, intending to enhance the performance of GHE, the present study conducts a computational investigation of the thermal performance of modified spiral tube vertical GHEs. Several modifications of uniform-pitched spiral GHE are made to increase its thermal performance. Some modifications are introduced as variable-pitched spiral tube GHE where spiral inlet pipes are densified in the lower part of GHEs by reducing pitch distance. Conversely, in some modifications, the position of the outlet straight pipe is changed. Water is considered as the working fluid and the inlet temperature of the water is maintained fixed at 300.15 K. After extensive analysis, it is evident that, when the outlet pipe is placed outside of the spiral coil, there is a 7.67 % enhancement in the thermal performance than a traditional uniform-pitched spiral tube GHE. However, modifications like variable-pitched spiral tube GHEs are not significant to improve the thermal performance due to the quick saturation of the ground soil temperature around the GHE pipes. To have a balance between heat transfer rate and pressure drop, thermal performance capability (TPC) and coefficient of performance improvement (COP imprvt ) criterion were evaluated and it is found that the uniform-pitched spiral tube GHE along with the outlet pipe at the outside of the spiral provides maximum thermal performance with a maximum TPC value of 1.062 and provides the positive value of COP imprvt criterion. The positive values of COP imprvt indicate that the spiral tube GHEs are energy efficient based on heat transfer and pressure drop. Moreover, spiral GHE with high-density polyethylene (HDPE), concrete pile, and sandy clay outperform the other materials for pipe, backfill, and soil, respectively. Specifically, HDPE pipe, concrete backfill, and sandy clay as soil offer around 7 %, 5 %, and 7.8 % higher thermal performance compared to polyethylene, sand silica, and clay, respectively.

Safflower polysaccharide ameliorates acute ulcerative colitis by regulating STAT3/NF-κB signaling pathways and repairing intestinal barrier function.

This study is to investigate the effect of SPS on the UC model. An animal model of UC induced by DSS was developed using C57BL/6 mice. The body weight was recorded every day, and the symptoms related to UC were detected. H&E staining, AB-PAS staining and PSR staining were used to evaluate the histopathological changes of the colon. Inflammation and mucosal barrier indicators were detected by qRT-PCR, and the 16 S rRNA sequence was used to detect the intestinal flora. SPS can significantly prevent and treat DSS-induced ulcerative colitis in animals. SPS significantly improved clinical symptoms, alleviated pathological damage, inhibited the infiltration of intestinal inflammatory cells. SPS treatment can protect goblet cells, enhance the expression of tight junction proteins and mucins, inhibit the expression of antimicrobial peptides, thereby improving intestinal barrier integrity. The prevention and treatment mechanism of SPS may be related to the inhibition of STAT3/NF-κB signaling pathway to regulate intestinal barrier function. In particular, SPS also significantly adjusted the structure of intestinal flora, significantly increasing the abundance of Akkermansia and Limosilactobacillus and inhibiting the abundance of Bacteroides. Overall, SPS has a significant therapeutic effect on ulcerative colitis mice, and is expected to play its value effectively in clinical treatment.

Alocasia macrorrhiza rhizome lectin inhibits growth of pathogenic bacteria and human lung cancer cell in vitro and Ehrlich ascites carcinoma cell in vivo in mice.

Cancer and antibiotic resistance represent significant global challenges, affecting public health and healthcare systems worldwide. Lectin, a carbohydrate-binding protein, displays various biological properties, including antimicrobial and anticancer activities. This study focused on anticancer and antibacterial properties of Alocasia macrorrhiza lectin (AML). AML, with a molecular weight of 11.0 ± 1.0 kDa was purified using Ion-exchange chromatography, and the homotetrameric form was detected by gel-filtration chromatography. It agglutinates mouse erythrocytes, that was inhibited by 4-Nitrophenyl-α-d-mannopyranoside. Maximum hemagglutination activity was observed below 60 °C and within a pH range from 8 to 11. Additionally, it exhibited moderate toxicity against brine shrimp nauplii with LD50 values of 321 µg/ml and showed antibacterial activity against Escherichia coli and Shigella dysenteriae. In vitro experiments demonstrated that AML suppressed the proliferation of mice Ehrlich ascites carcinoma (EAC) cells by 35 % and human lung cancer (A549) cells by 40 % at 512 µg/ml concentration. In vivo experiments involved intraperitoneal injection of AML in EAC-bearing mice for five consecutive days at doses of 2.5 and 5.0 mg/kg/day, and the results indicated that AML inhibited EAC cell growth by 37 % and 54 %, respectively. Finally, it can be concluded that AML can be used for further anticancer and antibacterial studies.

Hydrothermal Synthesis, Phase Analysis, and Magneto-Electronic Characterizations of Lead-Free Ferroelectric BM2+(Zn, Ca, Mg)T-BFO System.

In this study, lead-free BiM2+(Zn, Ca, Mg)Ti-BiFeO3 ceramics are fabricated under eco-friendly hydrothermal reaction conditions at 250 °C. XRD patterns show that all the synthesized compounds exhibit a phase coexistence of monoclinic and tetragonal perovskite-type structures with a morphotropic phase boundary at x = 0.4, with minimum impurity. The calculated average crystallite/grain size of the samples was close to 50 nm at full width at half-maximum of the main peak. The corresponding bonds of the constituent elements were observed by FTIR analysis, which further supports the formation of the local structure. EDS analyses detect all of the elements, their quantities, and compositional homogeneity. SEM data show agglomerated and nearly spherical morphology with an average particle size of about 128 nm. All synthesized ceramic powders revealed thermal stability with trivial mass loss up to investigated high temperatures (1000 οC). The dielectric constant reached its maximum at 38.7 MHz and finally remained constant after 80 MHz for all nanoceramics. Because of the complementary impact of different compositions, the most effective piezoelectric characteristics of d33 = 136 pCN-1, Pr = 8.6 pCN-1 cm-2, and kp = 11% at 30 °C were attained at x = 0.4 content for 0.4BiCaTi-0.6BiFeO3 ceramic. The measured magnetic hysteresis data (M-H curve) showed a weak ferromagnetic nature with the highest moment of ∼0.23 emu/g for 0.4BiCaTi-0.6BiFeO3, and other samples exhibited negligible ferromagnetic to diamagnetic transition. The optical response study shows that the 0.4BiMgTi-0.6BiFeO3 sample yielded the maximal transmittance (50%), whereas the 0.4BiCaTi-0.6BiFeO3 compound exhibited the highest refractive index. The calculated large band gap shows a high insulating or dielectric nature. Our findings demonstrate that the BiM2+Ti-BiFeO3 system, which was fabricated using a low-temperature hydrothermal technique, is an excellent lead-free piezoelectric and multiferroic nanoceramic.

Harnessing the potential of CsPbBr3-based perovskite solar cells using efficient charge transport materials and global optimization.

Perovskite solar cells (PSCs) have become a possible alternative to traditional photovoltaic devices for their high performance, low cost, and ease of fabrication. Here in this study, the SCAPS-1D simulator numerically simulates and optimizes CsPbBr3-based PSCs under the optimum illumination situation. We explore the impact of different back metal contacts (BMCs), including Cu, Ag, Fe, C, Au, W, Pt, Se, Ni, and Pd combined with the TiO2 electron transport layer (ETL) and CFTS hole transport layer (HTL), on the performance of the devices. After optimization, the ITO/TiO2/CsPbBr3/CFTS/Ni structure showed a maximum power conversion efficiency (PCE or η) of 13.86%, with Ni as a more cost-effective alternative to Au. After the optimization of the BMC the rest of the investigation is conducted both with and without HTL mode. We investigate the impact of changing the thickness and the comparison with acceptor and defect densities (with and without HTL) of the CsPbBr3 perovskite absorber layer on the PSC performance. Finally, we optimized the thickness, charge carrier densities, and defect densities of the absorber, ETL, and HTL, along with the interfacial defect densities at HTL/absorber and absorber/ETL interfaces to improve the PCE of the device; and the effect of variation of these parameters is also investigated both with and without HTL connected. The final optimized configuration achieved a VOC of 0.87 V, JSC of 27.57 mA cm-2, FF of 85.93%, and PCE of 20.73%. To further investigate the performance of the optimized device, we explore the impact of the temperature, shunt resistance, series resistance, capacitance, generation rate, recombination rate, Mott-Schottky, JV, and QE features of both with and without HTL connected. The optimized device offers the best thermal stability at a temperature of 300 K. Our study highlights the potential of CsPbBr3-based PSCs and provides valuable insights for their optimization and future development.

High efficiency Cu2MnSnS4 thin film solar cells with SnS BSF and CdS ETL layers: A numerical simulation.

The quaternary compound copper manganese tin sulfide Cu2MnSnS4 is a potential absorber semiconductor material for fabricating thin film solar cells (TFSC) thanks to their promising optoelectronic parameters. This article numerically investigated the performance of Cu2MnSnS4 (CMTS)-based TFSC without and with tin sulphide (SnS) back surface field (BSF) thin-film layer. First, the impact of several major influential parameters such as the active material's thickness, doping concentration of photoactive materials, density of bulk and interface defect, working temperature, and metal contact, were studied systematically without a BSF layer. Thereafter, the photovoltaic performance of the optimized pristine cell was further investigated with an SnS as BSF inserted between the absorber (CMTS) with a Platinum back metal of an optimized heterostructure of Cu/ZnO:Al/i-ZnO/n-CdS/p-Cu2MnSnS4/Pt. Thus, the photoconversion efficiency (PCE) of 25.43% with a J SC of 34.41nullmA/cm2 and V OC of 0.883 V was achieved under AM1.5G solar spectrum without SnS BSF layer. Furthermore, an improved PCE of 31.4% with a J SC of 36.21nullmA/cm2 and V OC of 1.07 V was achieved with a quantum efficiency of over 85% in the wavelengths of 450-1000 nm by the addition of SnS BSF layer. Thus, this obtained systematic and consistent outcomes reveal immense potential of CMTS with SnS as absorber and BSF, respectively and provide imperious guidance for fabricating highly a massive potential efficient solar cell.

Performance Enhancement of an MoS2-Based Heterojunction Solar Cell with an In2Te3 Back Surface Field: A Numerical Simulation Approach.

Researchers are currently showing interest in molybdenum disulfide (MoS2)-based solar cells due to their remarkable semiconducting characteristics. The incompatibility of the band structures at the BSF/absorber and absorber/buffer interfaces, as well as carrier recombination at the rear and front metal contacts, prevents the expected result from being achieved. The main purpose of this work is to enhance the performance of the newly proposed Al/ITO/TiO2/MoS2/In2Te3/Ni solar cell and investigate the impacts of the In2Te3 BSF and TiO2 buffer layer on the performance parameters of open-circuit voltage (V OC), short-circuit current density (J SC), fill factor (FF), and power conversion efficiency (PCE). This research has been performed by utilizing SCAPS simulation software. The performance parameters such as variation of thickness, carrier concentration, the bulk defect concentration of each layer, interface defect, operating temperature, capacitance-voltage (C-V), surface recombination velocity, and front as well as rear electrodes have been analyzed to achieve a better performance. This device performs exceptionally well at lower carrier concentrations (1 × 1016 cm-3) in a thin (800 nm) MoS2 absorber layer. The PCE, V OC, J SC, and FF values of the Al/ITO/TiO2/MoS2/Ni reference cell have been estimated to be 22.30%, 0.793 V, 30.89 mA/cm2, and 80.62% respectively, while the PCE, V OC, J SC, and FF values have been determined to be 33.32%, 1.084 V, 37.22 mA/cm2, and 82.58% for the Al/ITO/TiO2/MoS2/In2Te3/Ni proposed solar cell by introducing In2Te3 between the absorber (MoS2) and the rear electrode (Ni). The proposed research may give an insight and a feasible way to realize a cost-effective MoS2-based thin-film solar cell.

Isoliquiritigenin alleviates the development of alcoholic liver fibrosis by inhibiting ANXA2.

The study aimed to investigate the effect of isoliquiritigenin (ISL) on model of alcoholic liver fibrosis (ALF). C57BL/6 mice were used to establish animal model of ALF, HSC-T6 cells were used to establish alcohol-activated cell model, and tandem mass tag (TMT) assays were used to analyze the proteome. The results showed that ISL obviously alleviated hepatic fibrosis in model mice. ISL visually improved the area of liver pathological stasis and deposition of fibrillar collagen (Sirius Red staining, Masson staining), inhibited the mRNA expression levels of interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and interleukin 1ß (IL-1ß) in liver tissues. ISL down-regulated the mRNA expression levels of IL-6 and transforming growth factor-ß1(TGF-ß1) in activated hepatic stellate cells (HSCs). And ISL significantly reduced annexin A2 (ANXA2) in vitro detected by TMT proteomics technology. Interestingly, it was found for the first time that ISL could inhibit ANXA2 expression both in vivo and in vitro, block the sphingosine kinases (SPHKs)/sphingosine-1-phosphate (S1P)/interleukin 17 (IL-17) signaling pathway and regulate the expression of α-smooth muscle actin (α-SMA) by inhibiting the phosphorylation of signal transducer and activator of transcription 3 (STAT3) at the downstream signal to finally reverse HSCs activation and hepatic fibrosis. Thus, we demonstrated that ISL is a drug monomer with notable anti-hepatic fibrosis activity.

The antagonistic activity of Padina arborescens extracts on mPRα.

The current study attempted to evaluate the antagonistic activity of compounds isolated and purified from the marine algae Padina arborescens during cultivation. The compounds were collected on a filter, concentrated on ODS columns and separated by HPLC. Two peaks that showed competitive progesterone binding activity with membrane progesterone receptor α (mPRα) were purified. Their physiological activity was further uncovered by in vitro and in vivo oocyte maturation and ovulation-inducing assays using zebrafish. The compounds inhibited the induction of oocyte maturation and ovulation. Moreover, the results showed that the compounds have antagonistic activity against mPRα. The purified compounds with antagonistic activity against mPRα would be considered as new pharmaceutical candidate.

Concurrent investigation of antimony chalcogenide (Sb2Se3 and Sb2S3)-based solar cells with a potential WS2 electron transport layer.

Antimony (Sb) chalcogenides such as antimony selenide (Sb2Se3) and antimony sulfide (Sb2S3) have distinct properties to be used as absorber semiconductors for harnessing solar energy including high absorption coefficient, tunable bandgap, low toxicity, phase stability. The potentiality of Sb2Se3 and Sb2S3 as absorber material in Al/FTO/Sb2Se3(or Sb2S3)/Au heterojunction solar cells (HJSCs) with 2D tungsten disulfide (WS2) electron transport layer (ETL) layer has been investigated numerically using SCAPS-1D solar simulator. A systematic investigation of the impact of physical properties of each active material of Sb2Se3, Sb2S3, and WS2 on photovoltaic parameters including layer thickness, carrier doping concentration, bulk defect density, interface defect density, carrier generation, and recombination. This study emphasizes the exploration of causes of low performance of actual devices and demonstrates the individual variation in the open-circuit voltage (VOC), short-circuit current density (JSC), fill factor (FF), power conversion efficiency (PCE) and quantum efficiency (QE). Thereby, highly potential heterostructures of Al/FTO/WS2/absorber (Sb2Se3 or Sb2S3)/Au proposed, in which, the PCE over 28.20 and 26.60% obtained with V OC of 850 and 1230 mV, J sc of 38.0 and 24.0 mA/cm2, and FF of 86.0 and 89.0% for Sb2Se3 and Sb2S3 absorber, respectively. These detailed findings revealed that the Sb-chalcogenide heterostructure with potential WS2 ETL can be used to realize the fabrication of feasible thin film solar cells and thus the design of high-efficiency high-current (HEHC) and high-efficiency high-voltage (HEHV) solar panels.

Synthesis and Characterization of Eco-Friendly Bio-Composite from Fenugreek as a Natural Resource.

The present study show the usability of starch (tamarind) based-bio-composite film reinforced by fenugreek by various percentages to replace the traditional petrochemical plastics. The prepared bio-composite films were systematically characterized using the universal testing machine (UTM), soil degradation, scanning electron microscope (SEM), X-ray diffraction (XRD), thermogravimetric analyzer (TGA), and antibacterial tests. The experiments showed that a lower percentage of fenugreek improves biodegradation and mechanical strength. More than 60% of biodegradation occurred in only 30 days. Almost 3 N/mm2 tensile strength and 6.5% tensile strain were obtained. The presence of micropores confirmed by SEM images may accelerate the biodegradation process. Antibacterial activity was observed with two samples of synthesized bio-composite, due to photoactive compounds confirmed by FTIR spectra. The glass transition temperature was shown to be higher than the room temperature, with the help of thermal analysis. The prepared bio-composite containing 5% and 10% fenugreek showed antibacterial activities.

Transgenerational effects of bisphenol A on zebrafish reproductive tissues and sperm motility.

In a previous study, we demonstrated the next-generation effects and further transgenerational adverse effects of bisphenol A (BPA) in zebrafish. The adverse effects on reproductive factors, such as gonadal activity, fertility, hatching rate and malformation of embryo caused by the dietary administration on initial generation (F0) male and female zebrafish were continued until third filial (F3) generation. In this study, we examined how much amount of BPA contained in the diet was taken up by the zebrafish. We showed that only about 3.5-6.8% of BPA in the diet was taken into fish body. Also, we confirmed the transgenerational effects caused by 100 times lower amount of BPA than previous study. Even a low amount of BPA (1 µg/g diet) administered to F0 not only caused retraction of the ovaries and testes but also lowered the survival rate and increased the rate of malformation in the offspring. The effects were continued to F3 generation as previously described. Moreover, the sperm motility of the offspring of the BPA-treated ancestral animals was significantly lower, and this adverse effect was continued to F2 generations. These findings demonstrated that BPA at levels comparable to those ingested by humans can cause transgenerational adverse effects on fish reproduction.

Establishment of a steroid binding assay for membrane progesterone receptor alpha (PAQR7) by using graphene quantum dots (GQDs).

Currently, semiconductor nanoparticles known as quantum dots (QDs) have attracted interest in various application fields such as those requiring sensing properties, binding assays, and cellular imaging and are the very important in the acceleration of drug discovery due to their unique photophysical properties. Here, we applied graphene quantum dots (GQDs) for the binding assay of membrane progesterone receptor alpha (mPRα), one of the probable membrane receptors that have potential in drug discovery applications. By coupling the amino groups of mPRα with GQDs, we prepared fluorogenic GQD-conjugated mPRα (GQD-mPRα). When mixed with a progesterone-BSA-fluorescein isothiocyanate conjugate (P4-BSA-FITC) to check the ligand receptor binding activity of GQD-mPRα, fluorescence at 520 nm appeared. The fluorescence at 520 nm was reduced by the addition of free progesterone into the reaction mixture. GQD-coupled BSA (GQD-BSA) did not show a reduction in fluorescence at 520 nm. The results demonstrated the formation of a complex of GQD-mPRα and P4-BSA-FITC with ligand receptor binding. We established a ligand binding assay for membrane steroid receptors that is applicable for high-throughput assays.

Zebrafish stm is involved in the development of otoliths and of the fertilization envelope.

Using an in vivo assay, we selected 11 genes that were highly upregulated during the induction of ovulation in zebrafish using microarray analysis and RNA sequencing. The starmaker gene (stm) was one of these genes. Although stm has been previously reported to be involved in otolith formation during the early development of zebrafish, we detected its expression in eggs and showed that stm was related to fertilization by establishing an stm gene knockout strain using the CRISPR/Cas9 system. Further phenotypic analysis of stm knockout fish was conducted in this study. With a higher nonfertilization rate, the stm mutant strain showed an extremely low survival rate. Otoliths of stm homozygous mutant zebrafish showed abnormal morphology in embryos and adult fish. However, fish did not show any abnormalities in swimming behaviour in either embryos or adults. Stm proteins were detected on the chorion of ovulated eggs before spawning. Fibre-supported knob-like structures on the fertilization envelope (FE) also showed abnormal structures in stm mutants. The Stm protein is necessary for otolith formation, and a lack of Stm causes abnormal otolith formation. The partial defect of otolith formation does not cause defects in swimming behaviour. The Stm protein is expressed in the chorion and is responsible for the formation of fibre-supported knob-like structures on the FE. It was suggested that a lack of Stm caused a lower fertilization rate due to inadequate formation of the FE. LAY SUMMARY: In zebrafish, the protein Starmaker (Stm) was identified as having a role in ovulation. Stm is also known to be required for the formation of ear stones (otoliths) which are needed to keep the body in balance. Zebrafish lacking Stm were produced by genome editing. As expected, Stm-deficient fish formed abnormal otoliths. To investigate the role of Stm in ovulation, fertilization and early development, we tried mating of Stm mutants and observed their juveniles. Although no problem found in ovulation, we found low fertilization rate and abnormal structure of knob-like structure (small pit) on the egg membrane. Survival rate of embryos with abnormal egg membrane was extremely low. It was demonstrated that Stm protein is necessary to form the functional egg membrane to protect embryos from the outside environment.

Pax2a is expressed in oocytes and is responsible for early development and oogenesis in zebrafish.

Eleven genes, including pax2a, were selected as candidate ovulation-inducing genes on the basis of microarray analysis and RNA sequencing in our previous study. The purpose of this study was to investigate the role of the pax2a gene in the ovulation-inducing process. F2 pax2a homozygous mutant zebrafish possessing a deletion of 6 nucleotides were established in this study. However, the deletion included the start codon (ATG) of the pax2a gene, and the Pax2a protein was still detected, which indicated that the deletion caused a shift in the start codon to the next ATG, resulting in a 12-amino acid deletion. F2 pax2a homozygous mutant zebrafish showed ovulation. However, the embryos showed an abnormal oval shape at the epiboly stage that resulted in yolk and tail formation abnormalities and heart edema. The surviving F3 homozygous mutants did not develop ovaries. Pax2a was detected in oocytes and eggs but not after the Prim-22 stage. It is suggested that pax2a is expressed as a maternal gene in oocytes and is necessary for oogenesis and early development.

An agonist for membrane progestin receptor (mPR) induces oocyte maturation and ovulation in zebrafish in vivo.

The maturation and ovulation of fish oocytes are well-characterized biological processes induced by progestins via coordination of nongenomic actions and genomic actions. Previously, we established a procedure that enables the induction of oocyte maturation and ovulation in live zebrafish by simple administration of the natural teleost maturation-inducing hormone 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17,20ß-DHP) into the surrounding water. By this in vivo assay, the potencies of chemicals in inducing or preventing oocyte maturation and ovulation can be evaluated. The potencies of compounds in inducing ovulation of zebrafish oocytes also can be evaluated in vivo with improved in vitro assays. Here, we attempted to evaluate the effect of Org OD 02-0 (Org OD 02), a selective agonist for membrane progestin receptor (mPR), on fish oocyte maturation and ovulation with in vitro and in vivo assays. As reported previously, Org OD 02 triggered oocyte maturation in vitro. The same Org OD 02 triggered oocyte maturation within several hours in vivo. Surprisingly, Org OD 02 even induced ovulation both in in vivo and in vitro. Eggs from Org OD 02-induced ovulation could be fertilized by artificial insemination. The juveniles developed normally. These results indicated that Org OD 02 triggered physiological ovulation in live zebrafish. In summary, we have demonstrated the effect of Org OD 02 on fish oocyte maturation and ovulation in vitro and in vivo. The results suggested that Org OD 02 acted as an agonist not only of mPR but also of nuclear progesterone receptor (nPR).

Two-Step Mechanism of Cyclin B Degradation Initiated by Proteolytic Cleavage with the 26 S Proteasome in Fish.

To complete meiosis II, cyclin B is degraded in a short period by the inactivation of M-phase promoting factor (MPF). Previously, we showed that the destruction of cyclin B was initiated by the ubiquitin-independent proteolytic activity of the 26 S proteasome through an initial cut in the N-terminus of cyclin (at K57 in the case of goldfish cyclin B). We hypothesized that this cut allows cyclin to be ubiquitinated for further destruction by the ubiquitin-dependent proteolytic pathway, which leads to MPF inactivation. In this study, we aimed to identify the ubiquitination site for further degradation. The destruction of cyclin B point mutants in which lysine residues in a lysine-rich stretch following the cut site of cyclin B had been mutated was analyzed. All the lysine point mutants except K57R (a point mutant in which K57 was substituted with arginine) were susceptible to proteolytic cleavage by the 26 S proteasome. However, the degradation of the K77R and K7677R mutants in Xenopus egg extracts was significantly slower than the degradation of other mutants, and a 42 kDa truncated form of cyclin B was detected during the onset of the degradation of these mutants. The truncated form of recombinant cyclin B, an N-terminal truncated cyclin BΔ57 produced as cut by the 26 S proteasome, was not further cleaved by the 26 S proteasome but rather degraded in Xenopus egg extracts. The injection of the K57R, K77R and K7677R cyclin B proteins stopped cleavage in Xenopus embryos. From the results of a series of experiments, we concluded that cyclin B degradation involves a two-step mechanism initiated by initial ubiquitin-independent cleavage by the 26 S proteasome at lysine 57 followed by its ubiquitin-dependent destruction by the 26 S proteasome following ubiquitination at lysine 77.