Beyond the virus: a first look at coronavirus-themed Android malware.

As the COVID-19 pandemic emerged in early 2020, a number of malicious actors have started capitalizing the topic. Although a few media reports mentioned the existence of coronavirus-themed mobile malware, the research community lacks the understanding of the landscape of the coronavirus-themed mobile malware. In this paper, we present the first systematic study of coronavirus-themed Android malware. We first make efforts to create a daily growing COVID-19 themed mobile app dataset, which contains 4,322 COVID-19 themed apk samples (2,500 unique apps) and 611 potential malware samples (370 unique malicious apps) by the time of mid-November, 2020. We then present an analysis of them from multiple perspectives including trends and statistics, installation methods, malicious behaviors and malicious actors behind them. We observe that the COVID-19 themed apps as well as malicious ones began to flourish almost as soon as the pandemic broke out worldwide. Most malicious apps are camouflaged as benign apps using the same app identifiers (e.g., app name, package name and app icon). Their main purposes are either stealing users' private information or making profit by using tricks like phishing and extortion. Furthermore, only a quarter of the COVID-19 malware creators are habitual developers who have been active for a long time, while 75% of them are newcomers in this pandemic. The malicious developers are mainly located in the US, mostly targeting countries including English-speaking countries, China, Arabic countries and Europe. To facilitate future research, we have publicly released all the well-labelled COVID-19 themed apps (and malware) to the research community. Till now, over 30 research institutes around the world have requested our dataset for COVID-19 themed research.

The stimulatory effect of neuropeptide Y on growth hormone expression, food intake, and growth in olive flounder (Paralichthys olivaceus).

Neuropeptide Y (NPY) is a 36-amino acid peptide known to be a strong orexigenic (appetite-stimulating) factor in many species. In this study, we investigated the effect of NPY on food intake and growth in the olive flounder (Paralichthys olivaceus). Recombinant full-length NPY was injected intraperitoneally into olive flounder at the dose of 1 µg/g body weight; phosphate buffered saline was used as the negative control. In a long-term experiment, NPY and control groups were injected every fifth day over a period of 30 days. In a short-term experiment, NPY and control groups were given intraperitoneal injections and maintained for 24 h. Food intake and growth rates were significantly higher in fish injected with recombinant NPY than in the control fish (P < 0.05). Higher growth hormone (GH) and NPY mRNA transcript levels were observed in both experiments, indicating a stimulatory effect of NPY on GH release. These findings demonstrate that NPY is an effective appetite-stimulating factor in olive flounder with the potential to improve the growth of domestic fish species and enhance efficiency in aquaculture.

Characterization of pax3a and pax3b genes in artificially induced polyploid and gynogenetic olive flounder (Paralichthys olivaceus) during embryogenesis.

Although chromosome set manipulation techniques including polyploidy induction and gynogentic induction in flatfish are becoming increasingly mature, there exists a poor understanding of their effects on embryonic development. PAX3 plays crucial roles during embryonic myogenesis and neurogenesis. In olive flounder (Paralichthys olivaceus), there are two duplicated pax3 genes (pax3a, pax3b), and both of them are expressed in the brain and muscle regions with some subtle regional differences. We utilized pax3a and pax3b as indicators to preliminarily investigate whether chromosome set manipulation affects embryonic neurogenesis and myogenesis using whole-mount in situ hybridization. In the polyploid induction groups, 94 % of embryos in the triploid induction group had normal pax3a/3b expression patterns; however, 45 % of embryos in the tetraploid induction group showed abnormal pax3a/3b expression patterns from the tailbud formation stage to the hatching stage. Therefore, the artificial induction of triploidy and tetraploidy had a small or a moderate effect on flounder embryonic myogenesis and neurogenesis, respectively. In the gynogenetic induction groups, 87 % of embryos in the meiogynogenetic diploid induction group showed normal pax3a/3b expression patterns. However, almost 100 % of embryos in the gynogenetic haploid induction group and 63 % of embryos in the mitogynogenetic diploid induction group showed abnormal pax3a/3b expression patterns. Therefore, the induction of gynogenetic haploidy and mitogynogenetic diploidy had large effects on flounder embryonic myogenesis and neurogenesis. In conclusion, the differential expression of pax3a and pax3b may provide new insights for consideration of fish chromosome set manipulation.

Sustainable synthesis of Ni, Mn co-doped FePO4@C cathode material for Na-ion batteries.

Olivine FePO4 is widely regarded as an optimal cathode material for sodium-ion batteries due to its impressive theoretical capacity of 177.7 mAh g-1. Nonetheless, the material's limited application stems from its intrinsic low electronic and ionic conductivities and ion diffusion rate. Previously, most modifications of olivine FePO4 are conducted through electrochemical or ion exchange processes in organic solvents, which severely restricted its potential for large-scale applications. In this research, a novel water-based ion exchange method is proposed for the synthesis of Ni-doped, Mn-doped, and Ni, Mn co-doped FePO4@C, which is non-toxic, cost-effective, and demonstrating promising prospects for various applications. Fe2.7Mn0.2Ni0.1PO4@C (0.2Mn0.1Ni-FP@C) is synthesized by a straightforward ion exchange method in aqueous media. The material exhibits a discharge capacity of 154.4 mAh g-1 at 0.1C rate. After 300 cycles at 1C, the capacity retention rate remains at 70.7 %. Numerous tests and calculations conducted in this study demonstrate that 0.2Mn0.1Ni-FP@C, modified through Mn3+ and Ni3+ co-doping, exhibits superior electrochemical performance due to its enhanced electronic conductivity and ion diffusion rate.

Rapid mechanochemical synthesis of high-performance Na4Fe2.94Al0.04(PO4)2(P2O7)/C cathode material for sodium-ion storage.

Na4Fe3(PO4)2(P2O7) is regarded as a promising cathode material for sodium-ion batteries due to its affordability, non-toxic nature, and excellent structural stability. However, its electrochemical performance is hampered by its poor electronic conductivity. Meanwhile, most of the previous studies utilized spray-drying and sol-gel methods to synthesize Na4Fe3(PO4)2(P2O7), and the large-scale synthesis of the cathode material is still challenging. This study presents a composite cathode material, Na4Fe2.94Al0.04(PO4)2(P2O7)/C, prepared via a straightforward ball-milling technique. By substituting Al3+ minimally into the Fe2+ site of NFPP, Fe defects are introduced into the structure, hindering the formation of NaFePO4 and thereby enhancing Na-ion diffusion kinetics and conductivity. Additionally, the average length of AlO bonds (2.18 Å) is slightly smaller than that of FeO bonds (2.19 Å), contributing to the superior structural stability. The smaller ionic radii of Al3+ induce lattice contraction, further enhancing the structural stability. Moreover, the surface of material particles is coated with a thin layer of carbon, ensuring excellent electrical conductivity and outstanding structure stability. As a result, the Na4Fe2.94Al0.04(PO4)2(P2O7)/C cathode exhibits excellent electrochemical performance, leading to high discharge capacity (128.1 mAh g-1 at 0.2 C), outstanding rate performance (98.1 mAh g-1 at 10 C), and long cycle stability (83.7 % capacity retention after 3000 cycles at 10 C). This study demonstrates a low-cost, ultra-stable, and high-rate cathode material prepared by simple mechanical activation for sodium-ion batteries which has application prospects for large-scale production.

Surface engineered hollow Ni-Co-P@TiO2-x nanopolyhedrons as high performance anode material for sodium storage.

With the proposal of carbon peaking and carbon neutrality goals, clean energy storage is attracting more and more attentions. In view of the lack of lithium resource in our earth, sodium-ion batteries are considered as the emerging and promising next-generation energy storage devices. Appropriate high-performance anode materials play a vital role in the development of sodium-ion batteries. Here, a core-shell hollow Ni-Co-P nanopolyhedron interconnected by oxygen defect TiO2 (Ni-Co-P@TiO2-x) is reported, which is synthesized by ion etching-hydrolysis and subsequent phosphatization/hydrogenation treatment using ZIF-67 as template and hybrid carbon source. The achieved Ni-Co-P@TiO2-x material has several distinct advantages including hollow core-shell structure, flexible conductive carbon matrix, stable electroactive coating layer, and efficient pseudocapacitive behavior, resulting in high reversible capacities, remarkable rate capability and excellent cycle stability. The synergetic battery-capacitor characteristic of Ni-Co-P@TiO2-x material makes it become a promising anode for sodium-ion batteries.

Earning Extra Performance From Restrictive Feedbacks.

Many machine learning applications encounter situations where model providers are required to further refine the previously trained model so as to gratify the specific need of local users. This problem is reduced to the standard model tuning paradigm if the target data is permissibly fed to the model. However, it is rather difficult in a wide range of practical cases where target data is not shared with model providers but commonly some evaluations about the model are accessible. In this paper, we formally set up a challenge named Earning eXtra PerformancE from restriCTive feEDdbacks (EXPECTED) to describe this form of model tuning problems. Concretely, EXPECTED admits a model provider to access the operational performance of the candidate model multiple times via feedback from a local user (or a group of users). The goal of the model provider is to eventually deliver a satisfactory model to the local user(s) by utilizing the feedbacks. Unlike existing model tuning methods where the target data is always ready for calculating model gradients, the model providers in EXPECTED only see some feedbacks which could be as simple as scalars, such as inference accuracy or usage rate. To enable tuning in this restrictive circumstance, we propose to characterize the geometry of the model performance with regard to model parameters through exploring the parameters' distribution. In particular, for deep models whose parameters distribute across multiple layers, a more query-efficient algorithm is further tailor-designed that conducts layerwise tuning with more attention to those layers which pay off better. Our theoretical analyses justify the proposed algorithms from the aspects of both efficacy and efficiency. Extensive experiments on different applications demonstrate that our work forges a sound solution to the EXPECTED problem, which establishes the foundation for future studies towards this direction.

An interwoven carbon nanotubes/cerium dioxide electrocatalyst accelerating the conversion kinetics of lithium sulfide toward high-performance lithium-sulfur batteries.

Rechargeable lithium-sulfur (Li-S) batteries with environmental friendliness, low price, high specific capacity and energy density could be promising alternatives to a larger scope of energy storage in the near future. However, the practical application is impeded by the intrinsic insulation of sulfur and the fatal shuttle effect during the (dis)charging process. Herein, we report a strategy to address the drawbacks of Li-S batteries by inserting an interwoven carbon nanotubes/cerium dioxide electrocatalyst interlayer material (CNTs@CeO2) between the sulfur cathode and the separator. In the CNTs@CeO2 composite, the conductive network interwoven by CNTs facilitates electron transportation, and the abundant active sites in CeO2 cavities ensuring the adsorption-catalytic conversion of lithium polysulfides as well as the hollow structure of CeO2 is conducive to rapid electrolyte penetration and lithium ion migration. Benefiting from such multifunction, the battery with a CNTs@CeO2 interlayer exhibits superior rate performance, delivering a high discharge specific capacity of 1040.6 mAh g-1 at 0.2C and 652.5 mAh g-1 at 4C, respectively. Moreover, the battery shows excellent cycling stability with a capacity decay rate of 0.064% per cycle at 1C over 1000 cycles. These promising results demonstrate the potential application of CeO2-based electrocatalysts for high energy density Li-S batteries.

Sphere-in-fiber hybrid of N-doped carbon/cerium dioxide as an interlayer material with superior electrocatalytic performance for lithium sulfide precipitation and conversion.

The inferior conductivity and infamous "shuttle effect" of lithium-sulfur (Li-S) batteries lead to low sulfur utilization and undesired cycle stability, which both seriously affect their practical application. Here, a multifunctional nanofiber material based on cerium dioxide spheres embedded inside nitrogen-doped carbon fibers (denoted as NCF@CeO2) fabricated by electrospinning technology is used as an interlayer for high-performance Li-S batteries. The nitrogen-doped carbon fiber skeleton matrix provides a through-conducting grid to accelerate electron transfer at the interface of the nitrogen-doped carbon and the CeO2, and the large specific surface area guarantees a sufficient interfacial fast-redox reaction for sulfur species. CeO2 with a hollow structure provides strong physicochemical adsorption of lithium polysulfides (LiPSs) to weaken the migration behavior, and abundant oxygen defects as catalytic active sites are conducive to lithium sulfide conversion. The "sphere in fiber" construction minimizes the direct contact between the catalyst and electrolyte, effectively avoiding side reactions. Based on the multiple functions of nitrogen-doped carbon fibers and CeO2, Li-S batteries with NCF@CeO2 interlayers exhibit superior electrochemical performances, including a high discharge specific capacity of 1072.9 mAh g-1 at 0.2 C and a low capacity decay rate of only 0.063% per cycle after 1000 cycles. Moreover, the mechanisms of LiPSs adsorption-conversion and the quantification of the catalytic ability are elaborately clarified.

A pre-oxidation strategy to improve architecture stability and electrochemical performance of Na2MnPO4F particles-embedded carbon nanofibers.

The rational design of an excellent architecture for active materials combined with carbon matrix is of particular importanceto obtain flexible electrode material with high electrochemical properties. Well-designed nanofibers possess unique 3D network structure, which can significantly improve the electron/ion transportation and supplies sufficient active sites for Li+/Na+ insertion. Electrospinning-carbonization technology is a popular strategy to prepare nanofibers with active material embedded in carbon. It is found that the architecture of nanofibers tended to be wrecked and destroyed during the carbonization process without pre-oxidation treatment. In this study, we prepared Na2MnPO4F particles embedded in carbon nanofibers (Na2MnPO4F/C) using PVP as carbon source and investigated the strengthen mechanism of pre-oxidation on their architecture. The experiment and simulation results demonstrate that, without pre-oxidation, the main chain of PVP is severely ruptured during the carbonization procedure, consequently leads to fractured architecture of Na2MnPO4F/C nanofibers. In contrast, with pre-oxidation treatment, a long-chain and heat-resistance structured carbon matrix formed, and Na2MnPO4F/C nanofibers with stable architecture and improved electrochemical performance can be achieved. This study demonstrates a promising guide to construct carbon based nanofiber electrodes with stable architecture and high electrochemical performance.

Mn3O4 anchored polypyrrole nanotubes as an efficient sulfur host for high performance lithium-sulfur batteries.

Lithium-sulfur batteries have attracted numerous attentions owing to their high theory discharge specific capacity and energy density. However, sulfur cathode usually suffers from poor cycle stability and slow reaction kinetics, caused by its poor conductivity, excessive volume changes during charge/discharge processes, complex sulfur species conversion reaction and the dissolution of polysulfide intermediates. Here, we present a free-standing framework of Mn3O4 nanoparticles combine with polypyrrole (PPy) nanotubes as host materials for lithium-sulfur batteries to overcome these issues. In this construction, PPy nanotubes serve as the excellent container of sulfur and physical barrier for the excessive volume expansion of sulfur during electrochemical reaction processes, and the nanotubes also provide an efficient conductive network for the rapid transmission of electrons and ions, while Mn3O4 nanoparticles facilitate trapping lithium polysulfides. The coordination of PPy nanotubes and Mn3O4 effectively alleviate the shuttle effect as well as enhance the utilization of sulfur. The obtained PPy@Mn3O4-S sample shows high capacities of 1419.9 and 925.5 mAh g-1 at 0.1 C and 1 C rate, respectively, and exhibits a low capacity fading rate of 0.062% per cycle for 800 cycles at 1 C rate. This work provides a new and effective way for the design of lithium-sulfur batteries with both high rate performance and long cycle stability.

Study on xLiVPO4F·yLi3V2(PO4)3/C Composite for High-Performance Cathode Material for Lithium-Ion Batteries.

Cathode materials made of xLiVPO4F·yLi3V2(PO4)3/C (x:y = 1:0, 2:1, 0:1) are synthesized via a feasible sol-gel method for high-performance lithium-ion batteries. The structures, morphology, and electrochemical properties of the composites are thoroughly investigated. The results show that LiVPO4F/C, Li3V2(PO4)3/C, and 2LiVPO4F·Li3V2(PO4)3/C can be synthesized under 750°C without the formation of impurities. Meanwhile, the unique morphology of the 2LiVPO4F·Li3V2(PO4)3/C composite, which is porous, with nanoflakes adhering to the surface, is revealed. This composite integrates the advantages of LiVPO4F and Li3V2(PO4)3. There are four discharge plateaus near 4.2, 4.1, 3.7, and 3.6 V, and the cathode material delivers high capacities of 143.4, 141.6, 133.2, 124.1, and 117.6 mAh g-1 at rates of 0.1, 0.2, 0.5, 1, and 2 C, respectively. More importantly, the discharge capacity can be almost fully recovered when the discharge rate returns to 0.1 C. The study is highly promising for the development of cathode material for LIBs.

A Comparative Study on Na2Fe0.6Mn0.4PO4F/C Cathode Materials Synthesized With Various Carbon Sources for Na-ion Batteries.

Na2Fe0.6Mn0.4PO4F/C composite materials are synthesized with various carbon sources via a simple spray-drying method in this study, and the effect of carbon sources on structure, morphology, and electrochemical properties of Na2Fe0.6Mn0.4PO4F/C materials are investigated in detail. XRD and SEM results indicate that the reduction ability of carbon sources has a key impact on the structure and morphology of Na2Fe0.6Mn0.4PO4F/C composite materials. Among these Na2Fe0.6Mn0.4PO4F/C materials, the sample prepared with ascorbic acid presents a uniform hollow spherical architecture. Electrochemical analysis demonstrates that the Na2Fe0.6Mn0.4PO4F/C sample prepared with ascorbic acid has optimal electrochemical performance. The sample shows high discharge capacities of 95.1 and 48.1 mAh g-1 at 0.05C and 1C rates, respectively, and it exhibits an improved cycle stability (91.7% retention after 100 cycles at 0.5C), which are superior to Na2Fe0.6Mn0.4PO4F/C materials prepared with other carbon sources. This study demonstrates that the reduction ability of carbon sources significantly influences the electrochemical properties of fluorophosphate/C composite materials. This work also provides a promising strategy to obtain high performance cathode materials for sodium-ion batteries.

Muscle fibre type composition in the lateral muscle of olive flounder Paralichthys olivaceus.

In this paper, a combined-method study has been made on the lateral muscle of the teleost olive flounder Paralichthys olivaceus in just-hatched and adult stages. In just-hatched stage, both slow and fast muscle fibres were detected: (1) in situ hybridization analysis indicated that slow and fast myosin heavy chain genes were specifically expressed in the superficial and deep part of the myotomal muscle, respectively; (2) immunohistochemistry analysis showed that fibres in the deep part reacted with anti-fast myosin antibody F310; (3) western blot analysis detected a weak expression of slow myosin and a strong expression of fast myosin. In adult stage, the slow and fast muscle fibres had their own distribution characteristics: (1) hematoxylin/eosin staining showed the histological characteristics of the muscle fibre composition; (2) histochemical observations showed that the deep muscle fibres, and some fibres near the epidermis, contain alkali-stable myofibrillar ATPase activity; (3) immunohistochemistry analysis indicated that all the deep muscle fibres reacted with F310 antibody and some fibres in the superficial layer of muscle also reacted with F310; (4) western blot analysis showed that fast myosin was expressed both in the blended muscles (the mix of superficial and deep muscles) and deep muscles, while slow myosin was mainly expressed in the blended muscles. These findings suggested that both slow and fast muscle fibres existed in the musculature of the olive flounder in just-hatched and adult stages. Notably, the adult fast fibres also exist in the superficial layer of the muscle.

Facile One-Step Hydrothermal Synthesis of Na3V2(PO4)2F3@C/CNTs Tetragonal Micro-Particles as High Performance Cathode Material for Na-Ion Batteries.

In this paper, we report a facile one-step hydrothermal method to synthesize tetragonal Na3V2(PO4)2F3@C particles which are connected by carbon nanotubes (CNTs) networks, using water as hydrothermal solvents. In this strategy, the reduction and crystallization of materials are carried out in the hydrothermal process (180°C, 12 h), no additional heat treatment is required. The well-crystallized Na3V2(PO4)2F3 tetragonal grains (5-10 µm) are coated with amorphous nano-carbon and connected by highly conductive CNTs. The addition of CNTs can not only improve the conductivity of materials but also effectively inhibit the Na3V2(PO4)2F3 grains over growth. The Na3V2(PO4)2F3@C/CNTs composite possesses very flat charge/discharge platforms of 3.6 and 4.1 V. The sample exhibits an initial discharge specific capacity of 120.2 and 74.3 mAh g-1 at 0.1 and 10 C rate, respectively, and shows excellent cyclical stability. The composite owns excellent electrochemical performances owing to the three-dimensional highly conductive network which is co-constructed by the CNTs and nano-carbon coating layer.

Spray-Drying Synthesis of LiFeBO3/C Hollow Spheres With Improved Electrochemical and Storage Performances for Li-Ion Batteries.

LiFeBO3/C cathode material with hollow sphere architecture is successfully synthesized by a spray-drying method. SEM and TEM results demonstrate that the micro-sized LiFeBO3/C hollow spheres consist of LiFeBO3@C particles and the average size of LiFeBO3@C particles is around 50-100 nm. The thickness of the amorphous carbon layer which is coated on the surface of LiFeBO3 nanoparticles is about 2.5 nm. LiFeBO3@C particles are connected by carbon layers and formed conductive network in the LiFeBO3/C hollow spheres, leading to improved electrical conductivity. Meanwhile, the hollow structure boosts the Li+ diffusion and the carbon layers of LiFeBO3@C particles protect LiFeBO3 from moisture corrosion. Consequently, synthesized LiFeBO3/C sample exhibits good electrochemical properties and storage performance.

Controllable Synthesis of Na3V2(PO4)3/C Nanofibers as Cathode Material for Sodium-Ion Batteries by Electrostatic Spinning.

Na3V2(PO4)3/C nanofibers are prepared by a pre-reduction assisted electrospinning method. In order to maintain the perfect fibrous architecture of the Na3V2(PO4)3/C samples after calcining, a series of heat treatment parameters are studied in detail. It is found that the heat treatment process shows important influence on the morphology and electrochemical performance of Na3V2(PO4)3/C composite nanofibers. Under the calcining conditions of 800°C for 10 h with a heating rate of 2.5°C min-1, the well-crystallized uniform Na3V2(PO4)3/C nanofibers with excellent electrochemical performances are successfully obtained. The initial discharge specific capacities of the nanofibers at 0.05, 1, and 10C are 114.0, 106.0, and 77.9 mAh g-1, respectively. The capacity retention still remains 97.0% after 100 cycles at 0.05C. This smooth, uniform, and continuous Na3V2(PO4)3/C composite nanofibers prepared by simple electrospinning method, is expected to be a superior cathode material for sodium-ion batteries.

A novel process for preparation of titanium dioxide from Ti-bearing electric furnace slag: NH4HF2-HF leaching and hydrolyzing process.

A novel process to prepare titanium dioxide from Ti-bearing electric furnace slag by NH4HF2-HF leaching and hydrolyzing process has been developed. In this present study, the effects of [NH4+]/[F] mXolar ratio, leaching temperature, [F] concentration, liquid/solid mass ratio, leaching time on the Ti extraction, and the phase transformations have been investigated to reveal the leaching mechanism of Ti-bearing electric furnace slag in NH4HF2-HF solution. In the NH4HF2-HF leaching process, the MgTi2O5 and Al2TiO5 are converted to TiF62- and Mg-Al-bearing precipitate. Ti extraction rate reached 98.84% under the optimal conditions. In addition, 98.25% iron ions can be removed in the presence of NaCl prior to hydrolysis process. The effects of pH and temperature on the selective hydrolysis of TiF62- during hydrolysis process were also studied. In the hydrolysis process, the TiF62- is converted to (NH4)2TiOF4. By calcination, high grade TiO2 powder with its purity of 99.88% was obtained, using which the products, well crystallized anatase and rutile, were obtained through roasting at 800°C and 1000°C, respectively.

Conserved elements in the nanos3 3'UTR of olive flounder are responsible for the selective retention of RNA in germ cells.

In teleost fish, primordial germ cells (PGCs) are specified very early during embryogenesis and migrate to the site that gonads are formed. A previous study indicated that nanos3 is specifically expressed in PGCs, and the 3' untranslated region (UTR) of nanos3 is responsible for the localization of mRNA in these cells. In this study, we aimed to investigate the functional regions of nanos3 3'UTR in olive flounder using truncated and mutated nanos3 3'UTRs fused to chimeric RNAs and microinjected into fertilized zebrafish eggs. The results indicated that a 68-bp functional element in the nanos3 3'UTR of olive flounder played important roles in the protection and degradation of RNA. Within this element, a U-rich region was identified to be responsible for the protection of RNA in PGCs and two GCAC sites for the degradation of RNA in somatic cells. The first GCAC was located adjacently to the U-rich region and the second GCAC within the U-rich region. Overall, we concluded that the two GCACs were the binding sites of miR-430, a microRNA that suppresses translation, whereas the U-rich region was the binding site of Dnd, a protein that antagonizes the miR-430-mediated silencing of mRNA.

The duplicated paired box protein 7 (pax7) genes differentially transcribed during Japanese flounder (Paralichthys olivaceus) embryogenesis.

PAX are important regulators of developmental processes. PAX7 plays crucial roles in patterning of the dorsal central nervous system (CNS), neural crest (NC), and skeletal muscle. Here, we identified six spliced isoforms of pax7a and one pax7b and characterized their expression patterns. All of flounder Pax7a-1, Pax7a-2, Pax7a-3, and Pax7b contain a conserved paired domain (PD), an octapeptide motif (OP), and a paired type homeodomain (HD). However, the PD of Pax7a-4 and the HD of Pax7a-5 are not intact, and there is no HD in Pax7a-4 and Pax7a-6. pax7a and pax7b show distinct spatiotemporal expression patterns during embryogenesis. Whole-mount in situ hybridization demonstrates that the expression patterns of pax7a and pax7b are overlapping but distinguishable in the dorsal central nervous system. pax7a is expressed in most part of the brain and the neural tube, while pax7b is expressed exclusively in the diencephalon and the midbrain. In addition, pax7a is also expressed in the cranial NC and the trunk NC. RT-PCR results show that there were different expression patterns between the different isoforms. These results indicate subfunction partitioning of the duplicated pax7 genes. The duplicated pax7 may provide additional flexibility in fine-tuning neurogenesis and somitogenesis.