In-Depth Investigation of the Mechanism of Dehydration-Induced Phase Transformation from Nb3O7(OH) to H-Nb2O5: A Theoretical and Experimental Approach.

H-Nb2O5 is a promising energy material, which can be typically obtained from any other polymorph after conducting high temperature calcination (∼1273 K). Recently, a low-temperature dehydration from Nb3O7(OH) was employed to prepare H-Nb2O5 at 723 K for 2 h, and yet the transformation mechanism has remained unclear in the literature. Here, the dehydration kinetic and phase transformation mechanism of the Nb3O7(OH) were investigated for the first time by experiments, density functional theory, and molecular dynamics calculations. After dehydration, the orthorhombic Nb3O7(OH) initially transformed into an intermediate Nb-O compound with dislocations, preserving parent structure, and subsequently transformed into monoclinic H-Nb2O5. The activation energy for the transformation from Nb3O7(OH) to H-Nb2O5 was as low as 1.35 eV, compared to that of T-Nb2O5 to H-Nb2O5 (3.60 eV). Furthermore, the defect-rich H-Nb2O5 obtained from Nb3O7(OH), does not exhibit pristine bound exciton state due to severe recombination of photogenerated carriers, resulting in poor photocatalytic activity.

Transcriptome analysis of immune-related gene expression in Yellow River carp (Cyprinus carpio var.) after challenge with Flavobacterium columnare.

Yellow River carp (Cyprinus carpio) is an economically-important freshwater fish. It is the common host of the epizootic bacterium Flavobacterium columnare, a common fish pathogen that causes columnaris disease resulting in aquacultural losses. However, information on the functions and mechanisms of the immune system of Yellow River carp infected with F. columnare is limited. Therefore, the aim of this study is to evaluate the genetic and histopathological effects of an experimentally-induced F. columnare infection in Yellow River carp. Sixty fish were divided into control (CT group) and challenged groups. The gills were collected for histological and transcriptome analysis to understand the host immune response after challenge with F. columnare. The infected fish of the IF group presented typical columnaris disease symptoms and higher mortality, as well as histological changes. However, some challenged fish showed asymptomatic infection (IC group). Additionally, there were 1776 significant differentially-expressed genes (DEGs) between the IC and CT groups, 1853 DEGs between the IF and CT groups, and 1836 DEGs between the IF and IC groups, All the DEGs were classified into three gene ontology categories, which were allocated to 158 KEGG pathways. Moreover, immune-related genes were confirmed by qRT-PCR. we quantified the level of IL-1, IL-6, TNF-α and IL-8 by ELISA. The results showed the highest expression levels of inflammatory cytokines as well as stress proteins and the adhesion molecules in the lF group, which may contribute to severe infection, and a higher case fatality rate, while the high expression of chemokines, costimulatory molecules and the up regulation of antigen presentation function could help the carp resist F. columnare infection.

Identification of suh gene and evidence for involvement of notch signaling pathway on gonadal differentiation of Yellow River carp (Cyprinus carpio).

The suh gene is crucial in Notch pathway and regulates mammalian gonad development. In this study, the sequences of suh1 and suh2 genes in Yellow River carp (Cyprinus carpio) were verified. The partial 5'-flanking regions of suh1 and suh2 were analyzed and several potential transcription factor-binding sites were identified. Phylogenetic, gene structure, and chromosome synteny analyses revealed that carp suh1 and suh2 were orthologs and homologous to vertebrate suh. Investigation of the expression profiles of suh1 and suh2 with qPCR showed that these genes were abundant in the brain and gonad of carp, with suh1 exhibiting sexual dimorphism expression pattern in gonad. To study the relationship between gonad differentiation and Notch signaling, primordial gonads were exposed to DAPT, an inhibitor of Notch signaling, in vitro and in vivo. The results revealed a significant downregulation of suh1 and other Notch genes in vitro. In addition, expression of male-biased genes, such as amh, dmrt1, etc., was downregulated, whereas that of female-biased genes, such as foxl2, gdf9, etc., was upregulated. When the primordial gonads were subjected to long-term DAPT exposure, an increased proportion of ovary and delay in testis development were observed. These results suggest that suh gene may have a conservative function between teleosts and mammals. Furthermore, Notch signaling was found to be involved in gonad differentiation in Yellow River carp, and DAPT was noted to inhibit and enhance the expression of male- and female-biased genes, respectively, and induce the increase in number of females.

Identification and profiling of Cyprinus carpio microRNAs during ovary differentiation by deep sequencing.

BACKGROUND: MicroRNAs (miRNAs) are endogenous small non-coding RNAs that regulate gene expression by targeting specific mRNAs. However, the possible role of miRNAs in the ovary differentiation and development of fish is not well understood. In this study, we examined the expression profiles and differential expression of miRNAs during three key stages of ovarian development and different developmental stages in common carp Cyprinus carpio. RESULTS: A total of 8765 miRNAs were identified, including 2155 conserved miRNAs highly conserved among various species, 145 miRNAs registered in miRBase for common carp, and 6505 novel miRNAs identified in common carp for the first time. Comparison of miRNA expression profiles among the five libraries identified 714 co-expressed and 2382 specific expressed miRNAs. Overall, 150, 628, and 431 specifically expressed miRNAs were identified in primordial gonad, juvenile ovary, and adult ovary, respectively. MiR-6758-3p, miR-3050-5p, and miR-2985-3p were highly expressed in primordial gonad, miR-3544-5p, miR-6877-3p, and miR-9086-5p were highly expressed in juvenile ovary, and miR-154-3p, miR-5307-5p, and miR-3958-3p were highly expressed in adult ovary. Predicted target genes of specific miRNAs in primordial gonad were involved in many reproductive biology signaling pathways, including transforming growth factor-ß, Wnt, oocyte meiosis, mitogen-activated protein kinase, Notch, p53, and gonadotropin-releasing hormone pathways. Target-gene prediction revealed upward trends in miRNAs targeting male-bias genes, including dmrt1, atm, gsdf, and sox9, and downward trends in miRNAs targeting female-bias genes including foxl2, smad3, and smad4. Other sex-related genes such as sf1 were also predicted to be miRNA target genes. CONCLUSIONS: This comprehensive miRNA transcriptome analysis demonstrated differential expression profiles of miRNAs during ovary development in common carp. These results could facilitate future exploitation of the sex-regulatory roles and mechanisms of miRNAs, especially in primordial gonads, while the specifically expressed miRNAs represent candidates for studying the mechanisms of ovary determination in Yellow River carp.

Transmission Mechanism and Logical Operation of Graphene-Doped Poly(vinyl alcohol) Composite-Based Memristor.

Memristors are considered the best candidates for nonvolatile memory and advanced computing technologies, and polymer and two-dimensional (2D) materials have been developed as functional layer materials in memristors with high-performance resistive switching characteristics. In this work, a polymer memristor with a graphene (Gr)-doped poly(vinyl alcohol) (PVA) composite acting as the functional layer was prepared. The memristor device exhibited superior performance with good retention and a comparatively large ON/OFF ratio at room temperature. Additionally, excellent logic operations were achieved. These satisfactory properties can be attributed to trap-induced carrier trapping and detrapping. In addition, the device exhibited stable bipolar resistive switching behavior over a moderate temperature range. This work provides insight into the transmission mechanism of polymer-based memristors and the reasons why they become unstable at high temperatures, demonstrating the potential applications of PVA-Gr-based polymer memristors as logic circuit units in integrated chips and artificial intelligence.

Oxygen-Vacancy-Mediated Large Binding Energy Exciton Dissociation in Nb3O7(OH) Nanorods with High Electron Mobility for CO2 Photoreduction.

Despite the excellent performance of Nb3O7(OH) in dye-sensitized solar cells and catalysis, its charge separation, transport, and structural properties remain poorly understood. Herein, the Nb3O7(OH) nanorods were prepared, and their structural characteristics, optoelectronic properties, and carrier mobility were also analyzed and investigated through a series of complex characterizations. Theoretical prediction suggested that the exciton binding energy of Nb3O7(OH) could be as high as 100.49 meV. The temperature-dependent photoluminescence (PL) of Nb3O7(OH) nanorods revealed two activation energies, and a higher proportion of long-lived components observed in the photoluminescence decay indicated effective electron trapping. That is, two energy states were present, hindering photogenerated charge recombination and promoting photocatalytic action. Current-voltage characteristics of the Nb3O7(OH) nanorod film were analyzed, revealing an ultrahigh carrier mobility of ∼310 cm2/V·s, ensuring fast and efficient electron transfer. Furthermore, Nb3O7(OH) nanorods were employed to reduce CO2, resulting in the effective production of CO and CH4. Overall, considering the presence of hydroxyl pairs on the surface of Nb3O7(OH), which facilitate the formation of the frustrated Lewis acid-base pairs and the activation of CO2, together with its effective electron trapping and charge transport, give Nb3O7(OH) nanorods a promising potential for CO2 reduction.

Ameliorative effects of epigallocatechin-3-gallate nanoparticles on 2,4-dinitrochlorobenzene induced atopic dermatitis: A potential mechanism of inflammation-related necroptosis.

Atopic dermatitis (AD) is a common autoimmune and chronic inflammatory cutaneous disease with a relapsing-remitting course. Necroptosis is a regulated necrotic cell death mediated by receptor-interacting protein 1 (RIP1), receptor-interacting protein 3 (RIP3), and mixed lineage kinase domain-like pseudokinase (MLKL), which is activated by tumor necrosis factor-α (TNF-α). However, the mechanism and the role of necroptosis have not been delineated in AD progression. (-)-Epigallocatechin-3-gallate (EGCG), the main biological activity of tea catechin, is well known for its beneficial effects in the treatment of skin diseases. Here, PEG-PLGA-EGCG nanoparticles (EGCG-NPs) were formulated to investigate the bioavailability of EGCG to rescue cellular injury following the inhibition of necroptosis after AD. 2,4-dinitrochlorobenzene (DNCB) was used to establish AD mouse models. As expected, topically applied EGCG-NPs elicited a significant amelioration of AD symptoms in skin lesions, including reductions in the ear and skin thickness, dermatitis score, and scratching behavior, which was accompanied by redox homeostasis restored early in the experiment. In addition, EGCG-NPs significantly decreased the expression of inflammatory cytokines like TNF-α, interferon-γ (IFN-γ), interleukin-4 (IL-4), interleukin-6 (IL-6), and interleukin-17A (IL-17A) in a time-dependent manner than those of in AD group. As a result, the overexpression of RIP1, RIP3, and MLKL in the entire epidermis layers was dramatically blocked by EGCG-NPs, as well as the expression ofphosphorylated p38 (p-p38), extracellular signal-regulated kinase 1 (ERK1), and extracellular signal-regulated kinase 2 (ERK2). These findings promote that EGCG-NPs formulation represents a promising drug-delivery strategy for the treatment of AD by maintaining the balance of Th1/Th2 inflammation response and targeting necroptosis.

Identification, molecular characterization and analysis of the expression pattern of SoxF subgroup genes the Yellow River carp, Cyprinus carpio.

Sox7, Sox17 and Sox18 are the members of the Sry-related high-mobility group box family (SoxF) of transcription factors. SoxF factors regulate endothelial cell fate as well as development and differentiation of blood cells and lymphatic vessels. There is very less information about the functions of these genes in fish. We obtained the full-length cDNA sequence of SoxF genes including Sox7, Sox17 and Sox18 in Cyprinus carpio, where Sox7 and Sox18 had two copies. The construction of a phylogenetic tree showed that these genes were homologous to the genes in other species. Chromosome synteny analysis indicated that the gene order of Sox7 and Sox18 was highly conserved in fish. However, immense change in genomic sequences around Sox17 had taken place. Numerous putative transcription factor binding sites were identified in the 5_ flanking regions of SoxF genes which may be involved in the regulation of the nervous system, vascular epidermal differentiation and embryonic development. The expression levels of SoxF genes were highest in gastrula, and was abundantly expressed in the adult brain.We investigated the expression levels of SoxF genes in five specific parts of the brain. The expression levels of Sox7 and Sox18 were highest in the mesencephalon, while the expression level of Sox17 was highest in the epencephalon. In carp, the expression patterns of SoxF genes indicated a potential function of these genes in neurogenesis and in vascular development. These results provide new information for further studies on the potential functions of SoxF genes in carp.

Transcriptome analysis of three critical periods of ovarian development in Yellow River carp (Cyprinus carpio).

Ovary development is a complex process involving numerous genes; the molecular mechanism underlying the ovary development of carp is still unknown. Here we used Illumina HiSeq™ 2500 to explore the transcriptome of undifferentiated gland (PG), juvenile ovary (OJ) and adult ovary (OA) of Yellow River carp (Cyprinus carpio). A total of 58,749 unigenes were obtained, comprising 45,707 known genes and 13,042 new genes. We identified differentially-expressed genes (DEGs) during development and characterized the functional properties of DEGs by comparison with the gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes databases. qRT-PCR was used to analyze the expression of 22 DEGs and the results corresponded with those of RNA-Seq. Among DEGs between PG and OJ, some upstream regulators of gonad development were upregulated in PG, such as cyp19a and sox9, while some oocyte-specific genes were upregulated in OJ, such as nobox, bmp15 and zp2. Among DEGs between OJ and OA, many oocyte physiological function-related genes were upregulated in OA, such as fem-1 and foxl2. GO analysis showed a higher number of DEGs from PG-OJ analysis were assigned to reproduction terms. Furthermore, our investigation has also revealed DEGs identified from PG-OJ analysis were enriched in several important functional pathways, such as Fanconi anemia and the notch signal pathway. These data suggested a dynamic shift in gene expression during ovary development, and DEGs between PG and OJ provided crucial candidate gene data for the study of ovarian differentiation. Additionally, a total of 1,776,769 single nucleotide polymorphisms and 157,279 INDEs were revealed from transcriptome data. This result will contribute to knowledge of ovary differentiation of Yellow River carp.

Identification of differentially-expressed genes in early developmental ovary of Yellow River carp (Cyprinus carpio var) using Suppression Subtractive Hybridization.

Ovary development appears to be under polygenic control, and is influenced by multiple genetic factors that may vary from organism to organism. To gain a better insight into the molecular mechanisms of carp ovary development, Suppression Subtractive Hybridization (SSH) DNA libraries in two species of Yellow River carp were analyzed. Primordial gonads and stage II ovaries were used as testers, and adult ovaries as drivers. One hundred and fifty differentially-expressed candidate genes were examined by Southern blot microarray hybridization. We identified 41 differentially-expressed genes in the PG (Primordial gonad) library and 37 in the stage II ovary library. Gene Ontology Biological Pathway analysis showed the genes were involved in signal transduction, proteolysis process, cell differentiation, TGF-ß signal and other biological responses. Twenty-two candidate genes were selected and further characterized using qRT-PCR. Pvalb, epd, and MYH were found specifically expressed in PG, while bmp2b, desmin and fp1 were specifically expressed in stage II ovary. Our results indicate that these genes could be used as biomarkers of the early development of carp ovary. This finding will provide a basis for further understanding of the complex gonad developmental molecular mechanisms in Yellow River carp.

Role of human DNA2 (hDNA2) as a potential target for cancer and other diseases: A systematic review.

DNA nuclease/helicase 2 (DNA2), a multi-functional protein protecting the high fidelity of genomic transmission, plays critical roles in DNA replication and repair processes. In the maturation of Okazaki fragments, DNA2 acts synergistically with other enzymes to cleave the DNA-RNA primer flaps via different pathways. DNA2 is also involved in the stability of mitochondrial DNA and the maintenance of telomeres. Moreover, DNA2 potentially participates in controlling the cell cycle by repairing the DNA replication faults at main checkpoints. In addition, previous evidences demonstrated that DNA2 also functions in the repair process of DNA damages, such as base excision repair (BER). Currently, large studies revealed the structures and functions of DNA2 in prokaryotes and unicellular eukaryotes, such as bacteria and yeast. However, the studies that highlighted the functions of human DNA2 (hDNA2) and the relationships with other multifunctional proteins are still elusive, and more precise investigations are immensely needed. Therefore, this review mainly encompasses the key functions of DNA2 in human cells with various aspects, especially focusing on the genome integrity, and also generalizes the recent insights to the mechanisms related to the occurrence of cancer and other diseases potentially linked to the mutations in DNA2.

The Effects of Disturbance on Hypothalamus-Pituitary-Thyroid (HPT) Axis in Zebrafish Larvae after Exposure to DEHP.

Di-(2-ethylhexyl) phthalate (DEHP) has the potential to disrupt the thyroid endocrine system, but the underlying mechanism is unknown. In this study, zebrafish (Danio rerio) embryos were exposed to different concentrations of DEHP (0, 40, 100, 200, 400 µg/L) from 2 to 168 hours post fertilization (hpf). Thyroid hormones (THs) levels and transcriptional profiling of key genes related to hypothalamus-pituitary-thyroid (HPT) axis were examined. The result of whole-body thyroxine (T4) and triiodothyronine (T3) indicated that the thyroid hormone homeostasis was disrupted by DEHP in the zebrafish larvae. After exposure to DEHP, the mRNA expressions of thyroid stimulating hormone (tshß) and corticotrophin releasing hormone (crh) genes were increased in a concentration dependent manner, respectively. The expression level of genes involved in thyroid development (nkx2.1 and pax8) and thyroid synthesis (sodium/iodide symporter, nis, thyroglobulin, tg) were also measured. The transcripts of nkx2.1 and tg were significantly increased after DEHP exposure, while those of nis and pax8 had no significant change. Down-regulation of uridinediphosphate-glucuronosyl-transferase (ugt1ab) and up-regulation of thyronine deiodinase (dio2) might change the THs levels. In addition, the transcript of transthyretin (ttr) was up-regulated, while the mRNA levels of thyroid hormone receptors (trα and trß) remained unchanged. All the results demonstrated that exposure to DEHP altered the whole-body thyroid hormones in the zebrafish larvae and changed the expression profiling of key genes related to HPT axis, proving that DEHP induced the thyroid endocrine toxicity and potentially affected the synthesis, regulation and action of thyroid hormones.

Identification and comparison of gonadal transcripts of testis and ovary of adult common carp Cyprinus carpio using suppression subtractive hybridization.

The limited number of gonad-specific and gonad-related genes that have been identified in fish represents a major obstacle in the study of fish gonad development and sex differentiation. In common carp Cyprinus carpio from China's Yellow River, the ovary and testis differ in volume and weight in adult fish of the same age. Comparing sperm, egg, and somatic cell transcripts in this carp may provide insight into the mechanisms of its gonad development and sex differentiation. In the present work, gene expression patterns in the carp ovary and testis were compared using suppression subtractive hybridization. Two bidirectional subtracted complementary DNA (cDNA) libraries were analyzed in parallel using testis or ovary as testers. Eighteen nonredundant clones were identified in the male library, including 15 known cDNAs. The expression patterns of selected genes in testis and ovary were analyzed using reverse transcriptase polymerase chain reaction. Tektin-1, GAPDS, FGFIBP, IGFBP-5, and an unknown gene from the Ccmg4 clone were observed to be expressed only in testis. GSDF, BMI1b, Wt1a, and an unknown gene from the Ccme2 clone were expressed at higher levels in testis than in ovary at sexual maturity. Thirty functional expressed sequence tags (ESTs) were identified in 43 sequenced clones in the female library, including 28 known cDNAs, one uncharacterized cDNA (EST clone), and one novel sequence. Eight identified ESTs showed significant differences in expression between the testis and the ovary. ZP3C and Psmb2 were expressed exclusively in ovary, whereas the expression levels of IFIPGL-1, Setd6, ATP-6, CDC45, AIF-1, and an unknown gene from the Ccfh2 clone were more strongly expressed in ovary than in testis. In addition, the expression of ZP3C, Wt1a, and Setd6 was analyzed in male and female gonads, heart, liver, kidney, and brain. ZP3C was expressed only in ovary. Setd6 expression was significantly stronger in female tissues than that in the male, except in the liver, and Wt1a expression showed sexual dimorphism in the kidney and liver. Results suggest that these genes could play key roles during carp growth, both in the gonad and other tissues. The results provide a resource for further investigation of molecular mechanisms responsible for gonad development and sex differentiation in Yellow River common carp.

Zebrafish as a model system to study toxicology.

Monitoring and assessing the effects of contaminants in the aquatic eco-environment is critical in protecting human health and the environment. The zebrafish has been widely used as a prominent model organism in different fields because of its small size, low cost, diverse adaptability, short breeding cycle, high fecundity, and transparent embryos. Recent studies have demonstrated that zebrafish sensitivity can aid in monitoring environmental contaminants, especially with the application of transgenic technology in this area. The present review provides a brief overview of recent studies on wild-type and transgenic zebrafish as a model system to monitor toxic heavy metals, endocrine disruptors, and organic pollutants for toxicology. The authors address the new direction of developing high-throughput detection of genetically modified transparent zebrafish to open a new window for monitoring environmental pollutants.