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Skeletal muscle contusion is among the most common injuries in traumatology and clinics of sports medicine. The injured muscle is vulnerable to re-injury owing to fibrosis formation. Given that the bone marrow stromal cell-derived exosomes (BMSC-Exos) displayed promising therapeutic effect for various tissues, we used BMSC-Exos to treat skeletal muscle contusion and investigated its effects on muscle healing. In this study, the in vivo model of skeletal muscle contusion was established by subjecting the tibialis anterior of young male mice to hit injury, and the in vitro inflammation model was established by lipopolysaccharide treatment on macrophages. Macrophage depletion model was built by intraperitoneal injection with clodronate-containing liposomes. Exosomes were isolated and purified from the supernatant of BMSCs using gradient centrifugation. Nanoparticle tracking analysis, transmission electron microscope, and western blot were used to identify the exosomes. HE stain, Masson stain, immunofluorescence, and biomechanical testing were carried out on the muscle tissue. In addition, enzyme-linked immunosorbent assay (ELISA) assays, real-time qPCR, flow cytometry, and PKH67 fluorescence trace were conducted in vitro. Intramuscular injection of BMSC-Exos to mice after muscle contusion alleviated inflammation level, reduced fibrosis size, promoted muscle regeneration, and improved biomechanical property. After macrophages depletion, the effects of BMSC-Exos were inhibited. In vitro, PKH-67 fluorescence was internalized into macrophages. BMSC-Exos promoted M2 macrophages polarization both in vivo and in vitro. At the same time, BMSC-Exos reduced the production of inflammatory cytokines under the inflammatory microenvironment and upregulated anti-inflammatory factors expression. In conclusion, BMSC-Exos attenuated muscle contusion injury and promoted muscle healing in mice by modifying the polarization status of macrophages and suppressing the inflammatory reaction.

The reconstruction of a blood supply system and myocardial recovery from inflamamtory reactions in the infract zone remains a challenge in cardiac regeneration after myocardial infarction. Here, we observed that the local myocardial cells and the clotted blood cells undergo cellular remodeling via cytoplasmic exocytosis and nuclear reorganization in zebrafish hearts after resection of the ventricular apex. The subsequent tissue regeneration processes were visualized by detection of the spatiotemporal expression of three tissue specific genes (α-SMA which marks for vasculature/fibrogenesis, Flk1for angiogenesis/hematopoiesis, and Pax3a for remusculogensis), and two histone modification markers (H3K9Ac and H3K9Me3 for chromatin remodeling). By analyzing the composition of the blastema tissue fractions we found that Krt5 peptide could promote F-actin assembly, BMP4-pSmad2/5/8 signaling activity, and H3K9Me3-mediated chromatin accessibility at the blastema representative genes in the cultured zebrafish embryonic fibroblasts. Further in vivo tests demonstrated that Krt5 interacted with beta actin, and promoted Gata3 expression and Flk1-GFP marked blastema angiogenesis. These results proposed a new Krt5-cytoskeleton-BMP4 mechanotransduction mechanism in the epithelial-dependent and cell phenotype conversion-based tissue regeneration.

Artificial domestication during aquaculture practice has strongly shaped the physiological characteristics of Perca fluviatilis. Thus, revealing the genetic changes in domesticated P. fluviatilis will improve aquaculture and selective breeding. In this study, comparative analysis of the liver transcriptome, proteome, and physiological and biochemical indices of domesticated and wild P. fluviatilis was conducted. Our results indicated that the activity of lipase and the content of glucose were higher; however, the total antioxidant capacity and superoxide dismutase were lower in domesticated P. fluviatilis. Integrated analysis of "omics" data identified 174 and 127 genes and proteins that showed consistent upregulation and downregulation in domesticated P. fluviatilis, respectively. GO and KEGG enrichment of differentially expressed genes and proteins and the protein-protein interaction network indicated that energy metabolism (lipid and carbohydrate metabolism) was enhanced, and that signal transduction and the stress response were reduced in domesticated P. fluviatilis. This study revealed that artificial domestication may significantly shape the physiological changes in energy metabolism and stress resistance in domesticated P. fluviatilis, which makes them more adaptable to the artificial aquaculture environment, thereby promoting growth and development.

Phenotypic plasticity is a rapid response mechanism that enables organisms to acclimate and survive in changing environments. The Chinese mitten crab (

Vacuolar ATPase (V-ATPase) is a proton pump driven by ATP hydrolysis, and it plays an important role in numerous biological processes, such as protein degradation and synthesis, cell growth, and cell autophagy. The V-ATPase subunit B (VATB) is a conservative and regulatory subunit required for ATP hydrolysis during proton pumping. The VATB of Eriocheir sinensis (EsVATB), which includes an open reading frame (ORF) length of 1467 bp encoding 489 amino acids, was cloned to unveil the biological function of VATB during the molting process of crustaceans. Spatial and temporal expression profiles showed that EsVATB was highly expressed in the posterior gill accompanied with the highest osmotic pressure in the premolt (PrM) stage. Meanwhile, the highest expression level of EsVATB was identified in the hepatopancreas and heart during the postmolt stage and epidermis in the intermolt stage, indicating that EsVATB may perform diverse biological functions in different tissues during the molting process. The individual crabs in the interference group showed a high mortality rate (74%) and a low molting rate (26%) and failed to form a new epicuticle in the PrM stage. Meanwhile, a significant difference in osmotic pressure was identified between the interference and control groups. Our results indicate that EsVATB is an indispensable functional gene that may participate in osmoregulation and help with the new epicuticle formation during the molting process of E. sinensis., Summary: V-ATPase subunit B may participate in osmoregulation and help with the new epicuticle formation during the molting process of Chinese mitten crab Eriocheir sinensis.

Body color variation has long been a hot research topic in evolutionary and functional biology. Oujiang color common carp (Cyprinus carpio var. color) is a well-known economical and ornamental fish. Three main types of pigments and four distinct color patterns are typical characters of Oujiang color common carp, which makes it an excellent fish model to study body coloration. In this study, skin transcriptome assembly and comparisons were conducted in two Oujiang color common carp varieties: whole red and whole white. Transcriptome comparison revealed that more differentially expressed energy metabolism genes were upregulated in whole white compared to whole red. The results indicated that energy metabolism genes might be strongly associated with environmental adaption and growth performance and likely affect the red and white color formation in Oujiang color common carp. Our study provided direct guidance for the aquaculture industrials of Oujiang color common carp and presented valuable genetic resources for body color research in fish.

mTOR is a typical and conserved serine/threonine protein kinase that regulates cell growth and metabolism of organisms. Molting is a fundamental biological process in Chinese mitten crab (Eriocheir sinensis) and is monitored by a series of genes and pathways. The structural and functional characteristics of EsmTOR was investigated to determine the role of mTOR in the molting process of. The intact CDS of EsmTOR is 7449 bp in length and encodes a polypeptide consisting of 2482 amino acids. EsmTOR was expressed in all eight tissues examined during the three molting stages (postmolt, intermolt andpremolt), with levels fluctuating significantly during the molting. RNA interference of EsmTOR significantly delayed molting, indicating that mTOR may be involved in the molting process of E. sinensis. Meanwhile, a substantial downregulation was observed for the expression of upstream genes involved in amino acid transport (EsSLC7A5 and EsVATB) and downstream genes promoting ribosomal protein synthesis (EsS6K1) in the mTOR signaling pathway, as well as typical molt-related genes (EsMIH and EsEcR) after EsmTOR RNAi treatment. In addition, EsRheb, a molecular marker for tissue growth, was also significantly down-regulated. This study suggests that EsmTOR plays a fundamental role in molting regulation through the SLC7A5-V-ATPase-mTORC1 gene network.

White hepatopancreas is a syndrome that has recently emerged in aquaculture of Chinese mitten crab (Eriocheir sinensis). High lethality of the disease caused large economic loss, which drew considerable attention of fish farmers and scientific researchers. In this study, hepatopancreas reference transcriptome was de novo assembled and differential expression analysis was conducted between white hepatopancreas and normal (yellow) hepatopancreas of E. sinensis. A total of 90,687 transcripts were assembled, and 27,387 were annotated. Transcriptomic comparison revealed 69 differentially expressed genes between individuals featuring white hepatopancreas and yellow hepatopancreas. Genes associated with immune response and cell death, include thioredoxin-related transmembrane protein 1, hemocytin, methuselah-like 1, and E3 ubiquitin-protein ligase, and they were up-regulated, whereas titin and 5-formyltetrahydrofolate cyclo-ligase, which are genes related to cell proliferation, were down-regulated in E. sinensis with white hepatopancreas syndrome. Our study provides novel insights into genetic causes of formation and novel gene markers for detection of white hepatopancreas syndrome in aquaculture of E. sinensis.

Atrial fibrillation (AF) affects30 million individuals worldwide. However, no genetic mutation from human patients with AF has been linked to inflammation. Here, we show that AF-associated human variant p.Ile138Thr in natriuretic peptide A (

Mitochondria maintain a distinct pool of ribosomal machinery, including tRNAs and tRNAs activating enzymes, such as mitochondrial tyrosyl-tRNA synthetase (YARS2). Mutations in YARS2, which typically lead to the impairment of mitochondrial protein synthesis, have been linked to an array of human diseases including optic neuropathy. However, the lack of YARS2 mutation animal model makes us difficult to elucidate the pathophysiology underlying YARS2 deficiency. To explore this system, we generated YARS2 knockout (KO) HeLa cells and zebrafish using CRISPR/Cas9 technology. We observed the aberrant tRNATyr aminoacylation overall and reductions in the levels in mitochondrion- and nucleus-encoding subunits of oxidative phosphorylation system (OXPHOS), which were especially pronounced effects in the subunits of complex I and complex IV. These deficiencies manifested the decreased levels of intact supercomplexes overall. Immunoprecipitation assays showed that YARS2 bound to specific subunits of complex I and complex IV, suggesting the posttranslational stabilization of OXPHOS. Furthermore, YARS2 ablation caused defects in the stability and activities of OXPHOS complexes. These biochemical defects could be rescued by the overexpression of YARS2 cDNA in the YARS2KO cells. In zebrafish, the yars2KO larva conferred deficient COX activities in the retina, abnormal mitochondrial morphology, and numbers in the photoreceptor and retinal ganglion cells. The zebrafish further exhibited the retinal defects affecting both rods and cones. Vision defects in yars2KO zebrafish recapitulated the clinical phenotypes in the optic neuropathy patients carrying the YARS2 mutations. Our findings highlighted the critical role of YARS2 in the stability and activity of OXPHOS and its pathological consequence in vision impairments.

Fertility and endocrine function rely on a tightly regulated synchronicity within the hypothalamic–pituitary–gonadal axis, for which the sex gonad serves as the primary source of sex steroid hormones and germ cells. To maintain hormonal stasis and fertility throughout the lifespan, inducing gonadal stem cell renewal is an attractive strategy. The follicle-stimulating hormone/cAMP/MAPK/Sox9 signaling axis and its regulated specific miRNAs are thought to regulate vertebrate gonadal development and sex differentiation, yet the regulatory networks are largely unknown. By genome-wide transcriptome mining and gonadal microinjections, we identify two G protein-coupled receptor (GPCR)-regulatory circuits: miR430a-Sox9a in the testis and miR218a-Sox9b in the ovary. Coinjection of a Sox9a-miR430a mixture promotes spermatogenesis, whereas Sox9b-miR218a mixture increases primordial ovarian follicles. Coimmunoprecipitation and mass spectrometry indicate that the two mixtures differentially modulate Sox9a/Sox9b multiple covalent modifications. We further reveal that miR430a and Sox9a synergistically activate testicular protein kinase C (PKC)/Akt signaling, whereas the miR218a and Sox9b mixture constrains ovary PKC/Akt signaling. pMIR-GFP reporter assay demonstrate that miR430a and miR218a target the 3′ untranslated region (UTR) of four GPCR targets (lgr4, grk5l, grk4, and grp157). Knockdown of these GPCR genes or two Sox9 genes alters miR430a and miR218a regulation in the above gonad-specific PKC and Akt signaling pathways. These results establish two specific miRNA-GPCR-Sox9 networks and provide mechanistic insight into gonadal differentiation and rejuvenation. Stem Cells 2019;37:1189–1199

Background Sexual precocity is a common biological phenomenon in animal species. A large number of precocity individuals were identified in Chinese mitten crab Eriocheir sinensis, which caused huge economic loss annually. However, the underlying genetic basis of precocity in E. sinensis remains unclear to date. Results In this study, morphological and histological observation and comparative transcriptome analysis were conducted among different stages of precocious one-year-old and normal two-year-old sexually mature E. sinensis. The expression profiles of the ovary, hepatopancreas, and eyestalk tissues were presented and compared. Genes associated with lipid metabolic process, lipid transport, vitelline membrane formation, vitelline synthesis, and neuropeptide hormone-related genes were upregulated in the ovary, hepatopancreas, and eyestalk of precocious E. sinensis. Our results indicated that the eyestalk was involved in the neuroendocrine system providing neuropeptide hormones that may induce vitellogenesis in the hepatopancreas and further stimulate ovary development. The hepatopancreas is a site for energy storage and vitellogenin synthesis, and it may assist oogenesis through lipid transport in precocious E. sinensis. Conclusion We provided not only an effective and convenient phenotype measurement method for the identification of potential precocious E. sinensis detection but also valuable genetic resources and novel insights into the molecular mechanism of precocity in E. sinensis. The genetic basis of precocity in E. sinensis is an integrated gene regulatory network of eyestalk, hepatopancreas, and ovary tissues. Electronic supplementary material The online version of this article (10.1186/s12863-019-0716-1) contains supplementary material, which is available to authorized users.

Chinese mitten crab (Eriocheir sinensis) is an important aquaculture species in Crustacea. Functional analysis, although essential, has been hindered due to the lack of sufficient genomic or transcriptomic resources. In this study, transcriptome sequencing was conducted on 59 samples representing diverse developmental stages (fertilized eggs, zoea, megalopa, three sub-stages of larvae, juvenile crabs, and adult crabs) and different tissues (eyestalk, hepatopancreas, and muscle from juvenile crabs, and eyestalk, hepatopancreas, muscle, heart, stomach, gill, thoracic ganglia, intestine, ovary, and testis from adult crabs) of E. sinensis. A comprehensive reference transcriptome was assembled, including 19,023 protein-coding genes. Hierarchical clustering based on 128 differentially expressed cuticle-related genes revealed two distinct expression patterns during the early larval developmental stages, demonstrating the distinct roles of these genes in "crab-like" cuticle formation during metamorphosis and cuticle calcification after molting. Phylogenetic analysis of 1406 one-to-one orthologous gene families identified from seven arthropod species and Caenorhabditis elegans strongly supported the hypothesis that Malacostraca and Branchiopoda do not form a monophyletic group. Furthermore, Branchiopoda is more phylogenetically closely related to Hexapoda, and the clade of Hexapoda and Branchiopoda and the clade of Malacostraca belong to the Pancrustacea. This study offers a high-quality transcriptome resource for E. sinensis and demonstrates the evolutionary relationships of major arthropod groups. The differentially expressed genes identified in this study facilitate further investigation of the cuticle-related gene expression networks which are likely associated with "crab-like" cuticle formation during metamorphosis and cuticle calcification after molting.

Alternative splicing is an essential molecular mechanism that increase the protein diversity of a species to regulate important biological processes. Ecdysone receptor (EcR), an essential nuclear receptor, is essential in the molting, growth, development, reproduction, and regeneration of crustaceans. In this study, the whole sequence of EcR gene from Eriocheir sinensis was obtained. The sequence was 45,481 bp in length with 9 exons. Moreover, four alternatively spliced EcR isoforms (Es-EcR-1, Es-EcR-2, Es-EcR-3 and Es-EcR-4) were identified. The four isoforms harbored a common A/B domain and a DNA-binding region but different D domains and ligand-binding regions. Three alternative splicing patterns (alternative 5′ splice site, exon skipping, and intron retention) were identified in the four isoforms. Functional studies indicated that the four isoforms have specific functions. Es-EcR-3 may play essential roles in regulating periodic molting. Es-EcR-2 may participate in the regulation of ovarian development. Our results indicated that Es-EcR has broad regulatory functions in molting and development and established the molecular basis for the investigation of ecdysteroid signaling related pathways in E. sinensis.

The common carp, Cyprinus carpio, is one of the most important cyprinid species and globally accounts for 10% of freshwater aquaculture production. Here we present a draft genome of domesticated C. carpio (strain Songpu), whose current assembly contains 52,610 protein-coding genes and approximately 92.3% coverage of its paleotetraploidized genome (2n = 100). The latest round of whole-genome duplication has been estimated to have occurred approximately 8.2 million years ago. Genome resequencing of 33 representative individuals from worldwide populations demonstrates a single origin for C. carpio in 2 subspecies (C. carpio Haematopterus and C. carpio carpio). Integrative genomic and transcriptomic analyses were used to identify loci potentially associated with traits including scaling patterns and skin color. In combination with the high-resolution genetic map, the draft genome paves the way for better molecular studies and improved genome-assisted breeding of C. carpio and other closely related species.

Nile tilapia (Oreochromis niloticus), one of the most important groups of food fishes in the world, has frequently suffered from serious challenge from pathogens in recent years. Immune responses of Nile tilapia should be understood to protect the aquaculture industry of this fish. The complement system has an important function in recognizing bacteria, opsonizing these pathogens by phagocytes, or killing them by direct lysis. In this study, two Nile tilapia complement component genes, complement component 1 inhibitor (C1INH) and complement component 8β subunit (C8β), were cloned and their expression characteristics were analyzed. C1INH cDNA was found containing a 1791 bp open reading frame (ORF) encoding a putative protein with 597 amino acids, a 101 bp 5′-untranslated region (UTR) and a 236 bp 3′-UTR. The predicted protein structure for this gene consisted of two Ig-like domains and glycosyl hydrolase family-9 active site signature 2. The C8β cDNA consisted of a 1761 bp ORF encoding 587 amino acids, a 15 bp 5′-UTR and a 170 bp 3′-UTR. The predicted protein of C8β contained three motifs, thrombospondin type-1 repeat, membrane attack complex/perforin domain, and LDL-receptor class A. Expression analysis revealed that these two complement genes were highly expressed in the liver, however, were weakly expressed in the gill, heart, brain, kidney, intestine, spleen and dorsal muscle tissues. The present study provided insights into the complement system and immune functions of Nile tilapia.

Domestication has altered a variety of traits within the Eurasian perch (Perca fluviatilis), including phenotypic, physiological and behavioral traits of Eurasian perch (Perca fluviatilis). Little is known, however, about the genetic changes between domesticated and wild Eurasian perch. In this study, we assembled a high-quality de novo reference transcriptome and identified differentially expressed genes between wild and domesticated Eurasian perch. A total of 113,709 transcripts were assembled, and 58,380 transcripts were annotated. Transcriptomic comparison revealed 630 differentially expressed genes between domesticated and wild Eurasian perch. Within domesticated Eurasian perch there were 412 genes that were up-regulated including MHCI, MHCII, chia, ighm within immune system development. There were 218 genes including try1, ctrl, ctrb, cela3b, cpa1 and cpb1, which were down-regulated that were associated with digestive processes. Our results indicated domestication drives the changes of immune and digestive system of Eurasian perch. Our study not only provide valuable genetic resources for further studies in Eurasian perch, but also provide novel insights into the genetic basis of physiological changes in Eurasian perch during domestication process.

The black carp Mylopharyngodon piceus (Cyprinidae), native to eastern Asian, is a large, commercially important fish, and has been introduced to many other countries for variable reasons. In this study, the complete mitochondrial genome sequences from three specimens of black carp were first determined and were used to evaluate the sister relationship between black carp and grass carp (Ctenopharyngodon idellus). Two individuals had a mitogenome of 16,609 bp, while the other was 16,611 bp in length. Similar to most vertebrates, the black carp contains the same gene order and an identical number of genes or regions, including 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and 1 putative control region. Phylogenetic analyses using three different computational algorithms (Maximum Parsimony, Maximum Likelihood, and Bayesian analysis) revealed two distinct clades in subfamily Leuciscinae. However, the sister taxonomic relationship of black carp and grass carp was not observed using sequences of nearly complete mitochondrial genomes, which suggests more nuclear gene markers are needed to resolve the phylogenetic relationship between black carp and grass carp.

Genome comparison has shed light on many fields of both basic and applied research, including the study of species phylogeny. Grass carp (Ctenopharyngodon idella) belongs to Cyprinidae, the largest freshwater fish family; but which subfamily it belongs to remains a controversial issue. In this study, the complete mitochondrial genome (mitogenome) sequence of grass carp was determined and phylogenetic analyses of all mitochondrial protein-coding genes and a nuclear gene (RAG 2) were conducted to explore the evolutionary relationship of grass carp with other cyprinid species. The mitogenome of grass carp is 16,609 bp in length. As with most other vertebrates, it contains the same gene order and an identical number of genes or regions, including 13 protein-coding genes, two rRNA genes, 22 tRNA genes and one putative control region. Phylogenetic analyses using two different datasets (mitochondrial and nuclear) and three different computational algorithms (Bayesian, MP and ML) all revealed two distinct groups with high statistical support, indicating that Cyprininae and Leuciscinae are two separate, valid subfamilies. Importantly, our phylogenetic result provides strong molecular evidence in support of the placement of Ctenopharyngodon in Leuciscinae rather than in Cyprininae.

Molting is a critical developmental process for crustaceans, yet the underlying molecular mechanism is unknown. In this study, we used RNA-Seq to investigate transcriptomic profiles of the hepatopancreas and identified differentially expressed genes at four molting stages of Chinese mitten crab (Eriocheir sinensis). A total of 97,398 transcripts were assembled, with 31,900 transcripts annotated. Transcriptomic comparison revealed 1,189 genes differentially expressed amongst different molting stages. We observed a pattern associated with energy metabolism and physiological responses during a molting cycle. In specific, differentially expressed genes enriched in postmolt were linked to energy consumption whereas genes enriched in intermolt were related to carbohydrates, lipids metabolic and biosynthetic processes. In premolt, a preparation stage for upcoming molting and energy consumption, highly expressed genes were enriched in response to steroid hormone stimulus and immune system development. The expression profiles of twelve functional genes detected via RNA-Seq were corroborated through real-time RT-PCR assay. Together, our results, including assembled transcriptomes, annotated functional elements and enriched differentially expressed genes amongst different molting stages, provide novel insights into the functions of the hepatopancreas in energy metabolism and biological processes pertaining to molting in crustaceans.

The complete mitochondrial genome of Oujiang color carp was determined to be 16,581 bp in length accurately using the next generation sequencing technology and bioinformatics tools. The complete mitochondrial genome of Oujiang color carp shows typical circular molecule structure of vertebrate's mitochondrial genome, which consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region. The whole genome base composition was estimated to be 31.89% A, 27.53% C, 15.76% G, and 24.82% T with A/T bias of 56.71%. The complete mitochondrial genome of Oujiang color carp provides the basis for genetic breeding and conservation studies.

The Redhead cichlid (Vieja synspila) is an important aquarium fish and a useful phylogenetic organism of the Cichlidae family. In this study, we sequenced the mitochondrial genome of the Redhead cichlid for the first time. The mitogenome (16,543 bp) had the typical mitochondrial characteristics of other cichlid fish, including 13 protein-coding, 22 tRNA, two rRNA genes and one putative control region. This sequence will be helpful in studying the phylogenetic relationships between cichlid fish.

BACKGROUND: Body color and coloration patterns are important phenotypic traits to maintain survival and reproduction activities. The Oujiang color varieties of common carp (Cyprinus carpio var. color), with a narrow distribution in Zhejiang Province of China and a history of aquaculture for over 1,200 years, consistently exhibit a variety of body color patterns. The molecular mechanism underlying diverse color patterns in these variants is unknown. To the practical end, it is essential to develop molecular markers that can distinguish different phenotypes and assist selective breeding. METHODOLOGY/PRINCIPAL FINDINGS: In this exploratory study, we conducted Roche 454 transcriptome sequencing of two pooled skin tissue samples of Oujiang common carp, which correspond to distinct color patterns, red with big black spots (RB) and whole white (WW), and a total of 737,525 sequence reads were generated. The reads obtained in this study were co-assembled jointly with common carp Roche 454 sequencing reads downloaded from NCBI SRA database, resulting in 43,923 isotigs and 546,676 singletons. Over 31 thousand (31,445; 71.6%) isotigs were found with significant BLAST matches (E

The present study investigated the influence of the cigarette smoke extract (CSE) on mammalian thioredoxin reductase (TrxR) activity. TrxR is a selenoenzyme with a selenocysteine (Sec) residue exposed on the enzyme’s surface. This unique Sec residue is particularly susceptible to modification by numerous types of electrophiles, leading to inactivation of TrxR and consequent cytotoxicity. Cigarette smoke contains various electrophiles, and the present study showed that CSE could inhibit intracellular TrxR through causing crosslinking and alkylation of TrxR1. TrxR inhibitory capacities of various CSEs were evaluated by using mouse-liver homogenate. Among the CSEs prepared from 18 commercial cigarette brands, TrxR inhibitory capacities of the maximum and the minimum had a 2.5-fold difference. Importantly, CSE’s inhibitory capacity greatly paralleled its cytotoxic potency in all cell lines used. Compared to cytotoxic assays, which have been widely used for evaluating cigarette toxicity but are not suitable for simultaneously examining a large number of cigarette samples, the present method was simple and rapid with a high-throughput feature and thus could be used as an auxiliary means to predict the cytotoxicity of a large number of cigarette samples, making it possible to extensively screen numerous agricultural and industrial measures that potentially affect cigarette safety.

Kashgarian loach, Triplophysayarkandensis (Day, 1877), a native species in the Tarim River of Northwest China, has been dramatically declined in population size in recent years. In this article, the mitochondrial genome of Kashgarian loach was first determined. The whole mtDNA sequence was 16,574 bp in length, which is similar to other bony fishes in gene order, including 2rRNA genes, 22tRNA, 13 protein-coding and 1 putative control region.

Grass carp (Ctenopharyngodon idella), a freshwater species native to China, has been introduced to about 100 countries/regions and poses both biological and environmental challenges to the receiving ecosystems. In this study, we analyzed genetic variation in grass carp from three introduced river systems (Mississippi River Basin in US, Danube River in Hungary, and Tone River in Japan) as well as its native ranges (Yangtze, Pearl, and Amur Rivers) in China using 21 novel microsatellite loci. The allelic richness, observed heterozygosity, and within-population gene diversity were found to be lower in the introduced populations than in the native populations, presumably due to the small founder population size of the former. Significant genetic differentiation was found between all pairwise populations from different rivers. Both principal component analysis and Bayesian clustering analysis revealed obvious genetic distinction between the native and introduced populations. Interestingly, genetic bottlenecks were detected in the Hungarian and Japanese grass carp populations, but not in the North American population, suggesting that the Mississippi River Basin grass carp has experienced rapid population expansion with potential genetic diversification during the half-century since its introduction. Consequently, the combined forces of the founder effect, introduction history, and rapid population expansion help explaining the observed patterns of genetic diversity within and among both native and introduced populations of the grass carp.

The midas cichlid (Amphilophus citrinellus) is an important aquarium fish that has served as a model organism for studying sympatric speciation. In this study, we sequenced the complete mitochondrial genome of the midas cichlid. We report that the cichlid’s mitochondrial genome is a circular DNA double strand of 16,521 bp length, which contains 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and 1 control region. The overall-base compositions of the H-strand are as follows: A, 28.56%; C, 30.69%; G, 15.11%; T, 25.64%. This study provides important genomic data to further the research of the genetic evolution of cichlids.

Cichlid fishes have played an important role in evolutionary biology and aquaculture industry. Nile tilapia (Oreochromis niloticus), blue tilapia (Oreochromis aureus) and Mozambique tilapia (Oreochromis mossambicus), the useful models in studying evolutionary biology within Cichlid fishes, are also mainly cultured species in aquaculture with great economic importance. In this paper, the complete nucleotide sequence of the mitochondrial genome for O. niloticus and O. aureus were determined and phylogenetic analyses from mitochondrial protein-coding genes were conducted to explore their phylogenetic relationship within Cichlids. The mitogenome is 16,625 bp for O. niloticus and 16,628 bp for O. aureus, containing the same gene order and an identical number of genes or regions with the other Cichlid fishes, including 13 protein-coding genes, two rRNA genes, 22 tRNA genes and one putative control region. Phylogenetic analyses using three different computational algorithms (maximum parsimony, maximum likelihood and Bayesian method) show O. niloticus and O. mossambicus are closely related, and O. aureus has remotely phylogenetic relationship from above two fishes.

The mitten crab, Eriocheir sensu stricto, is economically important in East Asia, although it is an invasive species in Europe and North America. Little is known about its population structure and historical demography in its native range, especially along the Pacific coast of China. We collected mitochondrial cytochrome oxidase subunit II and cytochrome b sequences from 154 individuals distributed in the rivers along the Chinese coast and 15 individuals from Japan. Phylogenetic analysis resulted in three major monophyletic groups: northern China, southern China and Japan. Negligible migration was detected among those groups by coalescent analysis. Hence, we support the recognition of three species: Eriocheir hepuensis in southern China, Eriocheir sinensis in northern China and Eriocheir japonica in Japan. The populations in the middle (the Oujiang and Minjiang Rivers) possess a mixture of haplotypes similar to either the northern or the southern haplotypes. We believe that secondary intergradation as the most likely cause of the clinal variation based on examining the genetic variation in the latitudinal space. The estimated divergence time between E. sinensis and E. hepuensis is 2.24 million years ago (Ma), while the divergence time between E. japonica and E. sinensis is 1.83 Ma. Both are in the late Pliocene, suggesting that land bridges associated with low sea level during that time might have severed as vicariant barriers for speciation. The divergence of the northern population and the 'northern haplotypes' in the middle population was estimated at 0.12 Ma, while the time separating the southern population and the 'southern haplotypes' in the middle populations was estimated as 0.16 Ma, implicating possible secondary contact in the late Pleistocene.

Glass red common carp (Cyprinus carpio var. wananensis) were occasionally found among wild common carp (Cyprinus carpio) 50 years ago. In this paper, we determined the complete sequences of Glass red common carp and wild common carp mitogenomes. Both mitogenomes exhibited the same length of 16,581 bp, order in 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and 1 control region. The sequence similarity between them reached 99.62% and 100% in 21 tRNA genes (excluding tRNA(Ser)) and 2 protein-coding genes (ATP8 and ND4L), respectively. The two mitogenomes will be useful in elucidating the evolutional relationship of the common carp.

In almost all vertebrates, the downstream of the sox9 signaling axis is well conserved for testis differentiation. The upstream genes of this pathway vary from species to species during evolution. Yet, little is known about how these signaling cascades are regulated and what cellular processes are dominant in ovary–testis transformation in juvenile zebrafish. In this study, we find that the transforming gonads undergo activation of sox9a-expressing stromal cells with increased deposition of extracellular matrix and formation of degenerative compartments. This leads to follicle disassembly, oocyte degeneration, follicle cell-cyp19a1a-amh conversions, and, eventually, formation of the testis cord. In vitro primary culture of juvenile ovary tissue in gonadotropins increases cytoplasmic accumulation of sox9a and p-Erk1/2, and induces mesenchymal morphology. MAPK inhibitors (MKI), a mixture of PD98059 and U0216, eliminate the cytoplasmic distribution but do not eradicate nuclear localization of sox9a and p-Erk1/2. Nuclear p53 are relatively increased in MKI-treated cells that exhibit less spreading and reduced proliferation. Despite uniform nuclear condensation, only a fraction of cells displayed the apoptotic phenotype. These results suggest that high levels of cytoplasmic sox9a and p-Erk1/2 activity activate stromal cells and enhance the production of extracellular matrix required for testis cord formation, whereas deregulation and translocation of sox9a and p-Erk1/2 induce follicle disassembly and incomplete apoptosis associated with nuclear p53. Together with the established FSH/cAMP/MAPK/AMH pathway in mammalian granulosa and Sertoli cells, we demonstrated that the sox9 axis signaling that determines testis formation in mammals also induces zebrafish ovary–testis transition, and adds to its conserved role in sex reversal.

Summary MicroRNAs (miRNAs) are endogenous small non-coding RNAs that play crucial roles in numerous biological processes. However, the role of miRNAs in skin color determination in fish has not been completely determined. Here, we identified that 13 miRNAs are differentially expressed between red and white skin. The analysis of miRNA spatial and temporal expression patterns suggests that miR-429 is a potential regulator of skin pigmentation. miR-429 silencing results in an obvious change in skin pigmentation. Bioinformatics analysis and a luciferase reporter assay show that miR-429 directly regulates expression of Foxd3 by targeting its 3′-untranslated (3′-UTR) region. miR-429 silencing leads to a substantial increase in the expression of Foxd3 in vivo, thereby repressing the transcription of MITF and its downstream genes, such as TYR, TYRP1 or TYRP2. These findings would provide a novel insight into the determination of skin color in fish.