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Yellowfin tuna (Thunnus albacares) is a valuable pelagic migratory fish with potential for aquaculture. Despite this, there is limited understanding of the biological and physiological characteristics of this species, particularly regarding sex differences in growth performance. The liver, a crucial organ for digestion and metabolism, plays a significant role in regulating fish growth. This study aimed to compare liver enzyme activities and transcriptome profiles between female and male yellowfin tuna to uncover the molecular mechanisms underlying difference between the sexes. The results revealed that female yellowfin tuna exhibited higher amylase and lipid metabolism enzyme activities, while male yellowfin tuna showed higher glucose-6-phosphate dehydrogenase and antioxidant enzyme activities. Additionally, through Illumina sequencing technology, the study generated 37.74 Gb of clean data and identified 36,482 unique genes (UniGenes) in the liver transcriptome. A total of 2542 differentially expressed genes were found, with enriched Gene Ontology terms and pathways related to metabolic processes, particularly lipid metabolism and transport. These findings suggest that female yellowfin tuna have superior digestive enzyme activities and lipid metabolism, while male yellowfin tuna excel in sugar metabolism, ATP production, and antioxidant defense. This study provides valuable insights into sex differences in yellowfin tuna and could aid in advancing full-cycle aquaculture practices for this species. [ABSTRACT FROM AUTHOR]

In this study, nano- SiO2 was synthesized using the sol-gel method to modify the properties of fly ash-slag geopolymers (FASGs). FASGs with six contents of sol-type nano- SiO2 (0, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5%) and two alkali dosages (5% and 7% of Na2O) were prepared. The influences of sol-type nano- SiO2 and alkali content on the compressive strength, flexural strength, drying shrinkage, and microstructure of FASG were studied. The results demonstrated that the early-age compressive and flexure strength of FASG can be enhanced by sol-type nano- SiO2 due to the improved microstructure and the reaction products. The improvement effect of sol-type nano- SiO2 on mechanical properties was more significant for FASGs with lower alkali dosages. The optimized content of sol-type nano- SiO2 in FASG was 0.2% for the mechanical properties. The addition of the sol-type nano- SiO2 can mitigate the drying shrinkage of the FASG when the content is lower than 0.4%. The sol-type nano- SiO2 can promote the formation of reaction products in FASG and result in a denser microstructure of FASG. [ABSTRACT FROM AUTHOR]

The blotched snakehead Channa maculata is an important economical freshwater species in East Asia. However, there has been relatively little research conducted on the correlation between gender and gut microbes. In this study, 36 of 1000 blotched snakeheads were randomly selected for growth performance measurement and gut microbiota high-throughput sequencing. Results showed that microbial diversity, composition, and metabolic functions were altered by gender and growth performance except the microbial network. In our study, Proteobacteria were the most abundant phylum, with Fusobacteria showing enrichment in males and Bacteroidetes in females. Notably, phylum Deinococcus-Thermus was identified as a significant biomarker. The Cetobacterium was the most abundant genus-level taxon. Furthermore, gut microbes specializing in the production of gut-healthy substances, such as coenzymes and vitamins, were identified as biomarkers in the fast-growing group. Our investigation highlighted the impact of gender on the composition and abundance of gut microbial biomarkers in both males and females, thereby influencing differential growth performance through the modulation of specific metabolic functions. [ABSTRACT FROM AUTHOR]

The U6 promoter, a typical RNA polymerase III promoter, is widely used to transcribe small RNAs in vector-based siRNA systems. The RNAi efficiency is mainly dependent on the transcriptional activity of the U6 promoter. However, studies have found that U6 promoters isolated from some fishes do not work well in distantly related species. To isolate a U6 promoter with high transcriptional efficiency from fish, in this study, we cloned five U6 promoters in orange-spotted grouper, of which only the grouper U6-1 (GU6-1) promoter contains the OCT element in the distant region. Functional studies revealed that the GU6-1 promoter has high transcriptional ability, which could efficiently transcribe shRNA and result in target gene knockdown in vitro and in vivo. Subsequently, the deletion or mutation of the OCT motif resulted in a significant decrease in promoter transcriptional activity, demonstrating that the OCT element plays an important role in enhancing the grouper U6 promoter transcription. Moreover, the transcriptional activity of the GU6-1 promoter showed little species specificity. It not only works in the grouper but also possesses high transcriptional activity in the zebrafish. Knockdown of the mstn gene in zebrafish and grouper through shRNA driven by the GU6-1 promoter could promote fish growth, suggesting that the GU6-1 promoter can be used as a potential molecular tool in aquaculture practice. [ABSTRACT FROM AUTHOR]

Most grouper species are functional protogynous hermaphrodites, but the genetic basis and the molecular mechanisms underlying the regulation of this unique reproductive strategy remain enigmatic. In this study, we report a high‐quality chromosome‐level genome assembly of the representative orange‐spotted grouper (Epinephelus coioides). No duplication or deletion of sex differentiation‐related genes was found in the genome, suggesting that sex development in this grouper may be related to changes in regulatory sequences or environmental factors. Transcriptomic analyses showed that aromatase and retinoic acid are probably critical to promoting ovarian fate determination, and follicle‐stimulating hormone triggers the female‐to‐male sex change. Socially controlled sex‐change studies revealed that, in sex‐changing fish, the brain's response to the social environment may be mediated by activation of the phototransduction cascade and the melatonin synthesis pathway. In summary, our genomic and experimental results provide novel insights into the molecular mechanisms of sex differentiation and sex change in the protogynous groupers. [ABSTRACT FROM AUTHOR]

Yellowfin seabream Acanthopagrus latus is an important economic fish in Chinese coastal areas. Given its narrow distribution and overfishing, the genetic diversity of yellowfin seabream has been restricted for artificial breeding and reproduction. We performed full-length transcriptome sequencing and assembly of the genome of yellowfin seabream. A total of 68 086 unigenes were obtained, with an N50 of 3 391 bp on average length of 2 933 bp. A total number of 50 593 expressed sequence tags linked to simple sequence repeats (EST-SSR) were identified, among them dinucleotide repeats (40.6%) and AC/GT motifs (38.5%) were the most frequent. Of the 190 EST-SSRs for which PCR primer pairs were designed, 150 primer pairs successfully amplified target loci and 15 SSRs showed high polymorphism. The alleles per locus ranged 6–50 on average of 25.3. The expected and observed heterozygosity varied from 0.632 to 0.969 and from 0.519 to 0.953, respectively. The polymorphic index content (PIC) values of each locus ranged 0.587–0.966 on average of 0.851. Among six yellowfin seabream population samples preliminarily tested for genetic diversity and differentiation, the Fangchenggang (FCG) population in Guangxi Province had the highest mean observed heterozygosity (Ho) value (0.786), whereas the Zhangzhou (ZZ) population in Fujian Province had the lowest (0.678). The pairwise fixation index (Fst) values indicated significant population differentiation among six yellowfin seabream populations. This study provided evidence for the usefulness of the transcriptomic resource information and EST-SSR markers for natural resource conservation, population genetics, and breeding studies of yellowfin seabream in South China. [ABSTRACT FROM AUTHOR]

Egg storage for fertilization and seed production has great significance in aquaculture. Giant grouper(Epinephelus lanceolatus)is an economically important aquaculture species in China, and its fertilized eggs are much expensive. In this study, we tried to develop an in vitro egg storage system in this species. Storage conditions such as medium, temperature and pH were experimentally investigated. Results showed that eggs stored in L-15 medium(pH=8. 1)at 22 C for 2 h showed a relatively high fertilization rate(66. 4%) and a hatching rate(47. 9%). With supplementation of giant grouper serum and vitamin premix into L-15 medium, the storage time was prolonged and eggs still retained a relatively high viability. The fertilization and hatching rates from eggs stored for 8 h were 64. 4% and 44. 8%, respectively. This optimized short-term egg storage system would facilitate breeding practice and hatchery management in giant grouper. [ABSTRACT FROM AUTHOR]

During their breeding season, estrogen induces vitellogenin (VTG) production in the liver of teleost fish through estrogen receptors (ERs) that support oocyte vitellogenesis. There are at least three ER subtypes in teleost fish, but their roles in mediating E2-induced VTG expression have yet to be ascertained. In this study, we investigated the expression of vtgs and ers in the liver of orange-spotted grouper (Epinephelus coioides). Their expression levels were significantly increased in the breeding season and were upregulated by an estradiol (E2) injection in female fish, except for the expression of erβ1. The upregulation of vtgs, erα and erβ2 by E2 was also observed in primary hepatocytes, but these stimulatory effects could be abolished by ER antagonist ICI182780 treatment. Subsequent studies showed that ERβ antagonist Cyclofenil downregulated the E2-induced expression of vtg, erα, and erβ2, while the ERβ agonist DPN simulated their expression. Knockdown of erβ2 by siRNA further confirmed that ERβ2 mediated the E2-induced expression of vtgs and erα. To reveal the mechanism of ERβ2 in the regulation of erα expression, the erα promoter was cloned, and its activity was examined in cells. E2 treatment simulated the activity of the erα promoter in the presence of ERβ2. Deletions and site-directed mutations showed that the E2 up-regulated transcriptional activity of erα occurs through a classical half-estrogen response element- (ERE) dependent pathway. This study reveals the roles of ER subtypes in VTG expression in orange-spotted grouper and provides a possible explanation for the rapid and efficient VTG production in this species during the breeding season. [ABSTRACT FROM AUTHOR]

Simple Summary: C. sonnerati is an important marine fish species in coral reef ecosystems and has huge commercial value. This species serves as an excellent research model due to its complex social structures and behavior mechanisms. Nevertheless, owing to the lack of genomic resources, molecular genetic studies and genomic breeding remain unexplored in this species. Therefore, it is important to obtain more genome sequences of Cephalopholis grouper species for research on the classification, evolution, genetics, and biology of groupers. In the present study, we first assembled a high-quality, chromosome-level C.sonnerati genome, providing a valuable genome resource for further studies of the genetic conservation, resistance breeding, and evolution of C. sonnerati. The tomato hind, Cephalopholis sonnerati, is a bottom-dwelling coral reef fish, which is widely distributed in the Indo-Pacific and Red Sea. C. sonnerati also features complex social structures and behaviour mechanisms. Here, we present a high-quality, chromosome-level genome assembly for C. sonnerati that was derived using PacBio sequencing and Hi-C technologies. A 1043.66 Mb genome with an N50 length of 2.49 Mb was assembled, produced containing 795 contigs assembled into 24 chromosomes. Overall, 97.2% of the complete BUSCOs were identified in the genome. A total of 26,130 protein-coding genes were predicted, of which 94.26% were functionally annotated. Evolutionary analysis revealed that C. sonnerati diverged from its common ancestor with E. lanceolatus and E. akaara approximately 41.7 million years ago. In addition, comparative genome analyses indicated that the expanded gene families were highly enriched in the sensory system. Finally, we found the tissue-specific expression of 8108 genes. We found that these tissue-specific genes were highly enriched in the brain. In brief, the high-quality, chromosome-level reference genome will provide a valuable genome resource for studies of the genetic conservation, resistance breeding, and evolution of C. sonnerati. [ABSTRACT FROM AUTHOR]

Mandarin fish (Siniperca chuatsi) is an economically important freshwater fish cultured in China. In this species, females grow faster than males. However, due to the lack of available genomic and transcriptome information, the mechanisms of sex differentiation remain poorly understood. In this study, Illumina high-throughput sequencing technology was used to sequence four cDNA libraries; the tissues examined included hypothalamus, pituitary gland, ovary, and testis. A total of 134 124 high-quality unigenes were obtained on average length of 1 361 bp and N50 of 3 312 bp. A search of all-unigene sequences against NR, NT, SwissProt, KOG, KEGG, GO, and InterPro databases resulted in 59 688 (44.50%), 76 329 (56.91%), 50 432 (37.60%), 45 741 (34.10%), 48 760 (36.35%), 5 241 (3.91%), and 46 099 (34.37%) annotations, respectively. In a comparison of ovarian and testicular libraries, 15 289 ovary-biased genes and 10 035 testis-biased genes were identified, including a series of genes related to sex determination and differentiation, such as cyp19a1a, foxl2, sox9, dmrtl, amh, and others. In addition, 49 495 SSRs and 85 899 SNPs were detected in transcriptome data. Quantitative real-time PCR results of 15 sex-related functional genes indicated that RNA-seq data was reliable. This study will contribute to a better understanding of the molecular mechanisms of sex differentiation and development in Mandarin fish. [ABSTRACT FROM AUTHOR]

In order to satisfy heating, cooling and domestic hot water demand and energy conversion in luxury hotels, a feasible and novel multi-generation system taking advantage of the two-stage compressor was proposed and analyzed. The feature of this novel system is that the compressing power can be reduced and domestic water can be generated at the same time by adopting two-stage compressors instead of conventional one-stage compressor with a high compressing ratio. The energy-saving mechanism and two operating modes were introduced in detail. In a further way, the thermodynamic performance was calculated by Aspen Plus so as to make a better understanding of this novel system. And the calculation results showed that, in summer and transition seasons operating mode, the system can obtain COP (Coefficient of Performance) 7.3, and 60°C domestic hot water, when evaporating temperature is 4°C; while, in winter season operating mode, the system can obtain COP 3.1, and 58°C domestic hot water, when evaporating temperature is ‒24°C. Compared with the conventional independent systems, this system can achieve higher energy-efficient, higher waste heat recovery, reduce energy consumption, and meet multiple energy demands simultaneously. [ABSTRACT FROM AUTHOR]

Sex change in teleost fishes is commonly regulated by social factors. In species that exhibit protogynous sex change, such as the orange‐spotted grouper Epinephelus coioides, when the dominant males are removed from the social group, the most dominant female initiates sex change. The aim of this study was to determine the regulatory mechanisms of socially controlled sex change in E. coioides. We investigated the seasonal variation in social behaviours and sex change throughout the reproductive cycle of E. coioides, and defined the behaviour pattern of this fish during the establishment of a dominance hierarchy. The social behaviours and sex change in this fish were affected by season, and only occurred during the prebreeding season and breeding season. Therefore, a series of sensory isolation experiments was conducted during the breeding season to determine the role of physical, visual and olfactory cues in mediating socially controlled sex change. The results demonstrated that physical interactions between individuals in the social groups were crucial for the initiation and completion of sex change, whereas visual and olfactory cues alone were insufficient in stimulating sex change in dominant females. In addition, we propose that the steroid hormones 11‐ketotestosterone and cortisol are involved in regulating the initiation of socially controlled sex change. [ABSTRACT FROM AUTHOR]

Growth hormone–releasing hormone (GHRH) is a neuropeptide that controls growth hormone (GH) synthesis and release. In this study, the full-length cDNA of Mastacembelus armatus ghrh was obtained by rapid amplification of cDNA ends method. Sequence analysis showed that the cloned sequence is 1090 bp in length, containing an open reading frame (ORF) of 429 bp that encodes a precursor protein of 142 amino acids. Sequence alignment revealed that the 27-amino acid mature peptide of Ghrh in M. armatus is conserved. Real-time PCR showed that ghrh is highly expressed in the brain, with very low or no expression in other tissues. During embryonic and larval development, ghrh expression was low in embryos but increased gradually in the stages of larval development. The biological function of Ghrh peptide was further investigated in vivo. Ghrh injection could significantly upregulate the mRNA expression of growth hormone (gh) and insulin-like growth factor-1/2 (igf-1/2) in M. armatus. Our data indicate that Ghrh is able to activate the GH-IGFs axis in M. armatus. [ABSTRACT FROM AUTHOR]

Sexual patterns of teleosts are extremely diverse and include both gonochorism and hermaphroditism. As a protogynous hermaphroditic fish, all orange‐spotted groupers (Epinephelus coioides) develop directly into females, and some individuals change sex to become functional males later in life. This study investigated gonadal restructuring, shifts in sex hormone levels and gene profiles of cultured mature female groupers during the first (main) breeding season of 2019 in Huizhou, China (22° 42′ 02.6″ N, 114° 32′ 10.1″ E). Analysis of gonadal restructuring revealed that females with pre‐vitellogenic ovaries underwent vitellogenesis, spawning and regression and then returned to the pre‐vitellogenic stage in the late breeding season, at which point some changed sex to become males via the intersex gonad stage. A significant decrease in the level of serum 17β‐estradiol (E2) was observed during ovary regression but not during sex change, whereas serum 11‐ketotestosterone (11‐KT) concentrations increased significantly during sex change with the highest concentration in newly developed males. Consistent with serum hormone changes, a significant decrease in cyp19a1a expression was observed during ovary regression but not during sex change, whereas the expression of cyp11c1 and hsd11b2 increased significantly during sex change. Interestingly, hsd11b2 but not cyp11c1 was significantly upregulated from the pre‐vitellogenic ovary stage to the early intersex gonad stage. These results suggest that a decrease in serum E2 concentration and downregulation of cyp19a1a expression are not necessary to trigger the female‐to‐male transformation, whereas increased 11‐KT concentration and upregulation of hsd11b2 expression may be key events for the initiation of sex change in the orange‐spotted grouper. [ABSTRACT FROM AUTHOR]

Beta-hydroxysteroid dehydrogenases (β-HSDs) are a group of steroidogenic enzymes that are involved in steroid biosynthesis and metabolism, and play a crucial role in mammalian physiology and development, including sex determination and differentiation. In the present study, a genome-wide analysis identified the numbers of β -hsd genes in orange-spotted grouper (Epinephelus coioides) (19), human (Homo sapiens) (22), mouse (Mus musculus) (24), chicken (Gallus gallus) (16), xenopus (Xenopus tropicalis) (24), coelacanth (Latimeria chalumnae) (17), spotted gar (Lepisosteus oculatus) (14), zebrafish (Danio rerio) (19), fugu (Takifugu rubripes) (19), tilapia (Oreochromis niloticus) (19), medaka (Oryzias latipes) (19), stickleback (Gasterosteus aculeatus) (17) and common carp (Cyprinus carpio) (27) samples. A comparative analysis revealed that the number of β -hsd genes in teleost fish was no greater than in tetrapods due to gene loss followed by a teleost-specific whole-genome duplication event. Based on transcriptome data from grouper brain and gonad samples during sex reversal, six β -hsd genes had relatively high expression levels in the brain, indicating that these genes may be required for neurogenesis or the maintenance of specific biological processes in the brain. In the gonad, two and eight β -hsd genes were up- and downregulated, respectively, indicating their important roles in sex reversal. Our results demonstrated that β -hsd genes may be involved in the sex reversal of grouper by regulating the synthesis and metabolism of sex steroid hormones. [ABSTRACT FROM AUTHOR]

The tunnel muck has a great potential to be used as a recyclable engineering material in transit and other civil work projects instead of being deposited as construction waste. In this work, the geopolymer is generated by alkali-activated fly ashes, which act as cementitious materials to strengthen the tunnel muck. The tunnel muck has to be dehydrated, grinded, and screened before being treated by alkali-activated fly ash. The effect of the mass ratio between fly ash and tunnel muck (Mfa/Mtm), the mass ratio between Na2SiO3 solution and NaOH solution ( M Na 2 SiO 3 / M NaOH ), the ratio between liquid and solid (Mliquid/Msolid), and molarity of NaOH on the strength of geopolymer were systematically studied by conducting the uniaxial compression experiments. The experimental results indicate that the liquid-to-solid ratio is the most important parameter to the geopolymer strength after the alkali-activated fly ash treatment. On the contrary, molarity of NaOH is less effective on the geopolymer strength. Moreover, the optimum scheme is concluded according to the experimental results as follows: the mass ratio between tunnel muck and fly ash, the mass ratio between Na2SiO3 solution and NaOH solution, the ratio between liquid and solid, and molarity of NaOH are 1 : 2, 1.8, 0.18, and 10 mol/L, respectively. Meanwhile, the SEM images indicate that flocculence from the active substance in fly ash is a crucial component as the cementing material. [ABSTRACT FROM AUTHOR]

In this study, we injected cortisol into the protogynous orange-spotted grouper (Epinephelus coioides) to investigate the role of this hormone in sex change. Following injection, we evaluated gonadal changes, serum levels of steroid hormones, and sex-related gene expression during the processes of cortisol-induced sex change and cortisol withdrawal in the orange-spotted grouper. Cortisol treatment caused the degeneration of oocytes and induced sex change in a dose-dependent manner. Over the long-term, we observed a significant increase in serum 11-ketotestosterone (11-KT) levels in all cortisol-treated groups, although levels of 17β-estradiol did not change significantly. Consistent with the elevation of serum 11-KT levels, the expression of genes related to testicular development was also significantly up-regulated in the cortisol-treated groups. Based on our results, we propose that cortisol may trigger masculinization by inducing the synthesis of 11-KT and by directly activating the expression of sex-related genes. Furthermore, we found that cortisol-induced sex change was not permanent and could be reversed after the withdrawal of cortisol treatment. [ABSTRACT FROM AUTHOR]

Background: Spermatogenesis is an intricate process regulated by a finely organized network. The orange-spotted grouper (Epinephelus coioides) is a protogynous hermaphroditic fish, but the regulatory mechanism of its spermatogenesis is not well-understood. In the present study, transcriptome sequencing of the male germ cells isolated from orange-spotted grouper was performed to explore the molecular mechanism underlying spermatogenesis. Results: In this study, the orange-spotted grouper was induced to change sex from female to male by 17alpha-methyltestosterone (MT) implantation. During the spermatogenesis, male germ cells (spermatogonia, spermatocytes, spermatids, and spermatozoa) were isolated by laser capture microdissection. Transcriptomic analysis for the isolated cells was performed. A total of 244,984,338 clean reads were generated from four cDNA libraries. Real-time PCR results of 13 genes related to sex differentiation and hormone metabolism indicated that transcriptome data are reliable. RNA-seq data showed that the female-related genes and genes involved in hormone metabolism were highly expressed in spermatogonia and spermatozoa, suggesting that these genes participate in the spermatogenesis. Interestingly, the expression of zbtb family genes showed significantly changes in the RNA-seq data, and their expression patterns were further examined during spermatogenesis. The analysis of cellular localization of Eczbtb40 and the co-localization of Eczbtb40 and Eccyp17a1 in different gonadal stages suggested that Eczbtb40 might interact with Eccyp17a1 during spermatogenesis. Conclusions: Our study, for the first time, investigated the transcriptome of the male germ cells from orange-spotted grouper, and identified functional genes, GO terms, and KEGG pathways involved in spermatogenesis. Furthermore, Eczbtb40 was first characterized and its role during spermatogenesis was predicted. These data will contribute to future studies on the molecular mechanism of spermatogenesis in teleosts. [ABSTRACT FROM AUTHOR]

Aiming at the serious heat and cold loss of the building glass curtain wall in the field of amusement and tourism, and the need to meet the landscape requirements of the building facade, this paper put forward the idea of integrating the shading and consumption reduction of glass curtain wall with the landscape requirements, that is, the water curtain was set outside the glass curtain wall to form a landscape energy-saving integrated water curtain wall system, while meeting the needs of landscape and shading. By establishing the numerical calculation model of the system, the corresponding relationship between the thickness of water film and the weakening of solar radiation intensity was revealed, as well as the influence of wind speed and wind direction on the nozzle exit angle and velocity selection; and the synergistic law of air flow rate and air temperature drop amplitude. The results showed that the water film thickness at 3–4 cm can reduce the solar radiation by 65%–80%. The temperature of the air layer between the water film and the curtain wall decreased as the air flow rate decreased, when the thickness of water film was 2 cm and the air velocity was 0.5–1.5 m/s, the air temperature dropped to 2.47–3.6°C. Finally, through the analysis of the actual project—ICE World & WATER Park, the system can reduce 66.8% of solar radiation, and reduce the air layer temperature by 3.9°C. [ABSTRACT FROM AUTHOR]

Oocyte maturation and hydration are regulated by a complex interplay of various hormones and local factors. We have investigated the morphological changes of follicles and serum steroid levels during the HCG (human choionic gonadotophin)-induced oocyte maturation in the orange-spotted grouper. For the first time, a large-scale transcriptomic analysis of follicles during the maturation has been conducted in a fish species which produce pelagic oocytes. Eight cDNA libraries of follicle samples, from full-grown immature follicles to mature follicles, were constructed. A total of 402,530,284 high-quality clean reads were obtained after filtering, 79.66% of which perfectly mapped to the orange-spotted grouper genome. Real-time PCR results of 12 representative genes related to oocyte maturation and hydration verified the reliability of the RNA-seq data. A large number of genes related to oocyte maturation and hydration were identified in the transcriptome dataset. And the transcriptomic analysis revealed the dynamic changes of the steroid synthesis pathway and the pathway of hydration during oocyte maturation. The present study will facilitate future study on the oocyte maturation and hydration in the orange-spotted grouper and other marine pelagic egg spawner. [ABSTRACT FROM AUTHOR]

Follicle-stimulating hormone (FSH) signaling is considered to be essential for early gametogenesis in teleosts, but its functional roles during sex differentiation are largely unknown. In this study, we investigated the effects of long-term and short-term FSH injection on sex differentiation in the protogynous orange-spotted grouper (Epinephelus coioides). Long-term FSH treatment initially promoted the formation of ovaries but subsequently induced a male fate. The expression of female pathway genes was initially increased but then decreased, whereas the expression of male pathway genes was up-regulated only during long-term FSH treatment. The genes related to the synthesis of sex steroid hormones, as well as serum 11-ketotestosterone and estradiol, were also up-regulated during long-term FSH treatment. Short-term FSH treatment activated genes in the female pathway (especially cyp19a1a) at low doses but caused inhibition at high doses. Genes in the male pathway were up-regulated by high concentrations of FSH over the short term. Finally, we found that low, but not high, concentrations of FSH treatment activated cyp19a1a promoter activities in human embryonic kidney (HEK) 293 cells. Overall, our data suggested that FSH may induce ovarian differentiation or a change to a male sex fate in the protogynous orange-spotted grouper, and that these processes occurred in an FSH concentration-dependent manner. [ABSTRACT FROM AUTHOR]

Sex differentiation in teleost fishes occurs in response to sex determination signals, which induce the gonad to develop as either an ovary or testis. However, sex differentiation mechanisms in fishes are diverse, and information on gonad differentiation in sex changing fishes remains limited. The orange-spotted grouper (Epinephelus coioides) is a protogynous hermaphroditic fish that provides an ideal model for investigating gonad differentiation in vertebrates. In this study, Transcriptome data showed that expression levels of amh and amhrII in gonads were increased during sex differentiation. Then we investigated the effect of overexpression anti-Müllerian hormone (Amh) on gonad development in juvenile orange-spotted groupers. Expression levels of female-related genes and serum 17β-estradiol levels were decreased, while expression of male-related genes and serum 11-ketotestosterone levels were increased in fish fed with amh -plasmid. Overexpression of Amh was also promoted the spermatogonia proliferation and induced the development of male gonads in undifferentiated orange-spotted groupers, but that this male tendency was preceded by female differentiation. In summary, these results illustrated that Amh overexpression by amh -plasmid feeding induced male gonad development in undifferentiated groupers. [ABSTRACT FROM AUTHOR]

Socially controlled sex change in teleosts is a dramatic example of adaptive reproductive plasticity. In many cases, the occurrence of sex change is triggered by a change in the social context, such as the disappearance of the dominant individual. The orange‐spotted grouper Epinephelus coioides is a typical protogynous hermaphrodite fish that changes sex from female to male and remains male throughout its life span. In this study, male‐to‐female sex reversal in male Epinephelus coioides was successfully induced by social isolation. The body length and mass, gonadal change, serum sex steroid hormone levels and sex‐related gene expression patterns during the process of socially controlled male‐to‐female sex reversal in E. coioides were systematically examined. This report investigates the physiological mechanisms of the socially controlled male‐to‐female sex reversal process in a protogynous hermaphrodite grouper species. The results enable us to study the physiological control of sex change, not only from female to male, but also from male to female. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the gonadal development of 10‐ to 43‐mo‐old diploid and triploid orange‐giant grouper hybrids, Epinephelus coioides♀ × Epinephelus lanceolatus♂, was investigated. The diploid hybrid groupers exhibited normal gonadal development and experienced vitellogenesis at 43 mo of age. In contrast, the triploid gonad was masculinized and gradually filled with spermatogenic cysts. Radioimmunoassays revealed that the diploid hybrids showed high serum E2 levels at 10 and 43 mo and high T levels at 43 mo, while the triploid hybrids showed high E2 levels at 18 and 30 mo and high T levels at 18 mo. Furthermore, the messenger RNA (mRNA) expression of genes related to reproductive regulation was examined in these hybrids. The mRNA levels of fshb, fshr, lhb, lhr, dmrt1, and sox9 varied significantly during gonadal development. Interestingly, the expression levels of fshr, lhr, dmrt1, and sox9 were higher in triploid hybrids than in diploid hybrids. The hyperactive expression of these genes may be associated with the gonadal masculinization of triploid hybrids. [ABSTRACT FROM AUTHOR]

Interspecies hybridization is widely used in aquaculture as a beneficial strategy. Diploid and triploid hybrids have been detected from the interspecies hybridization of Epinephelus coioides ♀ × Epinephelus lanceolatus ♂. This is the first report of triploidization through hybridization in grouper. Confirmation has been obtained through flow cytometry, karyotyping and erythrocyte nuclei measurement. The chromosome numbers of E. coioides, E. lanceolatus, diploid hybrid grouper are 48 and triploid hybrid grouper are 72. Measurements of erythrocyte nuclei indicate that triploid fish have a larger nuclear surface than the diploid groupers, and the average ratio of triploid to diploid surface area is 1.59. During the first 1.5 years, triploid hybrid groupers grow faster than diploid hybrid groupers or either parent species. The average growth rate of triploid hybrids is 1.61 times greater than that of diploid hybrids at 6 months of age and 1.43 times greater at 18 months of age. The triploid hybrid groupers are inferior in gonadal development, with no primary-growth-stage oocytes appearing in the gonads at 18 months of age. Morphological studies indicate that triploid hybrid groupers have distinctive differences in snout length, eye diameter, body trunk shape, and tail shape development compared with diploid hybrid groupers. Triploid hybrid groupers have an advantage in growth ability, and artificial breeding of triploid groupers might be of great potential use in the grouper aquaculture industry. [ABSTRACT FROM AUTHOR]

The giant grouper ( Epinephelus lanceolatus) is a coral fish with high commercial value in Southeast Asia. In the present study, we isolated 11 microsatellite DNA markers, and analysed the genetic diversity and differentiation between cultured stocks and wild populations of the giant grouper originating from the South China Sea. A total of 390 alleles at 11 microsatellite loci were detected in 130 individuals from five different populations. The expected heterozygosity varied from 0.131 to 0.855 with a mean value of 0.623 and the observed heterozygosity varied from 0.145 to 0.869 with a mean value of 0.379. The allelic richness and heterozygosity studies revealed that the genetic diversity of the cultured population was significantly reduced when compared with that of the wild population. The F , pairwise F values, analysis of molecular variance (AMOVA), three-dimensional factorial correspondence analysis and structure analysis revealed significant population differentiation between the cultured stocks and the wild populations, among the three cultured populations and between the two wild populations. These differences may be caused by random genetic drift, the effects of artificial selection and founder effects. Our results will be useful in the management of cultured stocks and conservation of wild populations of the giant grouper. [ABSTRACT FROM AUTHOR]

We present the complete mitochondrial genome ofEpinephelus coioidesin this study. The mitochondrial genome is 16,458 bp in length, containing 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. All of them are encoded on the heavy strand except ND6 and 8 tRNA genes on the light strand. The nucleotide compositions of the light strand are 28.88% of G, 28.75% of T, 26.58% of A and 15.80% of C. All the protein-coding genes share ATG initiation codon except ATP6 with CTG and COXI with GTG, and four types of inferred termination codons are T (ND2, COXII, ND3, ND4 and Cytb), TA (COXIII), TAA (ND1, ATP8, ND4L, ND5, ATP6 and COXI) and TAG (ND6). There are 10 intergenic spacers, 5 gene overlaps and no tandem repeat sequence. Gene arrangement and distribution are consistent with the typical vertebrates. [ABSTRACT FROM PUBLISHER]

The complete mitochondrial genome of theEpinephelus tukulawas presented in this study. The mitochondrial genome is 16,503 bp long and consists of 13 protein-coding genes, two rRNA genes, 22 tRNA genes and a control region. The gene order and composition ofEpinephelus tukulamitochondrial genome was similar to that of most other vertebrates. The nucleotide compositions of the light strand are 28.37% of A, 29.00% of C, 26.36% of T and 16.26% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and seven tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM AUTHOR]

In this study, we have sequenced the complete mitochondrial genome of theParastromateus niger. The mitochondrial genome is 16,561 bp long and contains 13 protein-coding genes, two rRNA genes, 22 tRNA genes and a control region. The gene order and composition ofParastromateus nigermitochondrial genome is similar to that of most other vertebrates. The nucleotide compositions of the light strand are 28.23% of A, 29.51% of C, 26.01% of T and 16.16% of G. With the exception of five tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM AUTHOR]

We present the complete mitochondrial genome of the Trachinotus ovatus in this study. The mitochondrial genome is 16,563 bp long and consists of 13 protein-coding genes, two rRNA genes, 22 tRNA genes and a control region. The gene order and composition of T. ovatus mitochondrial genome was similar to that of most other vertebrates. The nucleotide compositions of the light strand are 29.03% of A, 28.86% of C, 26.23% of T and 15.88% of G. With the exception of ND6 and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. Two copies of tandem repeat sequence (56 bp) was observed in the 5′ end of the control region. [ABSTRACT FROM AUTHOR]

The spotted scat (Scatophagus argus) is an economically important cultured marine fish that exhibits a typical sexual size dimorphism (SSD). SSD has captivated considerable curiosity for farmed fish production; however, up till now the exact underlying mechanism remains largely unclear. As an important digestive and metabolic organ, the liver plays key roles in the regulation of fish growth. It is necessary to elucidate its significance as a downstream component of the hypothalamic-pituitary-liver axis in the formation of SSD. In this study, the liver physiological differences between the sexes were evaluated in S. argus, and the activity of several digestive and metabolic enzymes were affected by sex. Females had higher amylase, protease, and glucose-6-phosphate dehydrogenase activities, while males exhibited markedly higher hepatic lipase and antioxidant enzymes activities. A comparative transcriptomics was then performed to characterize the responsive genes. Illumina sequencing generated 272.6 million clean reads, which were assembled into 79,115 unigenes. A total of 259 differentially expressed genes were identified and a few growth-controlling genes such as igf1 and igfbp1 exhibited female-biased expression. Further analyses showed that several GO terms and pathways associated with metabolic process, particularly lipid and energy metabolisms, were significantly enriched. The male liver showed a more active mitochondrial energy metabolism, implicating an increased energy expenditure associated with reproduction. Collectively, the female-biased growth dimorphism of S. argus may be partially attributed to sexually dimorphic metabolism in the liver. These findings would facilitate further understanding of the nature of SSD in teleost fish. [ABSTRACT FROM AUTHOR]

Chromatin structure plays a pivotal role in maintaining the precise regulation of gene expression. Accessible chromatin regions act as the binding sites of transcription factors (TFs) and cis-elements. Therefore, information from these open regions will enhance our understanding of the relationship between TF binding, chromatin status and the regulation of gene expression. We employed an assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and RNA-seq analyses in the gonads of protogynous hermaphroditic orange-spotted groupers during sex reversal to profile open chromatin regions and TF binding sites. We focused on several crucial TFs, including ZNF263, SPIB, and KLF9, and analyzed the networks of TF-target genes. We identified numerous transcripts exhibiting sex-preferred expression among their target genes, along with their associated open chromatin regions. We then investigated the expression patterns of sex-related genes as well as the mRNA localization of certain genes during sex reversal. We found a set of sex-related genes that—upon further study—might be identified as the sex-specific or cell-specific marker genes that trigger sex reversal. Moreover, we discovered the core genes (gnas, ccnb2, and cyp21a) of several pathways related to sex reversal that provide the guideposts for future study. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of the hybrid grouper Epinephelus coioides ♀ × Epinephelus akaara ♂ is presented in this study. The mitochondrial genome is 16,458bp long and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. The gene order and composition of the hybrid grouper mitochondrial genome was similar to that of most other vertebrates. The nucleotide compositions of the light strand in descending order is 28.87% of G, 28.26% of T, 26.58% of A and 15.79% of C. With the exception of the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. The phylogenetic analysis by maximum-likelihood (ML) method showed that the hybrid grouper has the closer relationship to the hybrid grouper Epinephelus coioides ♀ × Epinephelus lanceolatus ♂. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of the hybrid grouperEpinehelus moara ♀×Epinephelus lanceolatus ♂is presented in this study. The mitochondrial genome is 16,418 bp long and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. The gene order and composition of the hybrid grouper mitochondrial genome were similar to that of most other vertebrates. The nucleotide compositions of the light strand in descending order was 28.86% of G, 28.61% of T, 26.46% of A and 16.08% of C. With the exception of the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. The phylogenetic analysis by maximum-likelihood (ML) method shows that the hybrid grouper has closer relationship toEpinehelus moaraandEpinehelus bruneus. [ABSTRACT FROM PUBLISHER]

The complete mitochondrial genome of theEpinephelus awoarawas presented in this study. The mitochondrial genome is 16 798-bp long and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region. The gene order and composition ofEpinephelus awoaramitochondrial genome was similar to that of most other vertebrates. The nucleotide compositions of the light strand in descending order is 27.35% of A, 16.53% of C, 28.44% of T, and 27.69% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. The phylogenetic analysis by maximum-likelihood (ML) method shows that theEpinephelus awoarawas closer toEpinephelus fasciatomaculosusin the phylogenetic relationship. [ABSTRACT FROM AUTHOR]

We presented the complete mitochondrial genome of theEpinephelus corallicolain this study. The mitochondrial genome is 16,647 bp long and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. The gene order and composition ofEpinephelus corallicolamitochondrial genome was similar to that of most other vertebrates. The nucleotide compositions of the light strand are 26.60% of A, 15.89% of C, 28.66% of T and 28.85% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of the hybrid grouper (Epinephelus coioides♀ × Epinephelus lanceolatus♂) was presented in this study. The mitochondrial genome is 16,743 bp long and consists of 13 protein-coding genes, two rRNA genes, 22tRNAgenes, and a control region. The gene order and the composition of the hybrid grouper mitochondrial genome were similar to that of most other vertebrates. The nucleotide compositions of the light strand are 26.56% of A, 15.79% of C, 28.74% of T, and 28.91% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of theEpinephelus fuscoguttatuswas presented in this study. The mitochondrial genome is 16,648 bp long and consists of 13 protein-coding genes, two rRNA genes, 22 tRNA genes, and a control region. The gene order and the composition ofE. fuscoguttatusmitochondrial genome were similar to that of most other vertebrates. The nucleotide compositions of the light strand are 26.91% of A, 15.58% of C, 29.19% of T, and 28.32% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM AUTHOR]

The red-spotted grouper (Epinephelus akaara) is one of the most commercially important aquatic species in China. However, its seedstock has low larval survival rates, and its stability is confronted with the danger of overexploitation. In this study, a high-density genetic map was constructed using 3435 single nucleotide polymorphisms (SNPs) from 142 first generation (F1) full-sib offspring and two parents of a red-spotted grouper population. The total genetic length of the map was 2300.12 cM with an average intermarker distance of 0.67 cM. Seventeen genome-wide significant quantitative trait loci (QTLs) for growth-related traits were detected on 24 linkage groups, including 5 QTLs for full length, 7 QTLs for body length, and 5 QTLs for body weight. The contribution values of explained phenotypic variance ranged from 10.7% to 12.9%. Moreover, 13 potential candidate genes for growth-related traits were identified. Collectively, these findings will be useful for conducting marker-assisted selection of the red-spotted grouper in future studies. [ABSTRACT FROM AUTHOR]

Giant groupers, the largest grouper type in the world, are of economic importance in marine aquaculture for their rapid growth. At the same time, bacterial and viral diseases have become the main threats to the grouper industry. Here, we report a high-quality genome of a giant grouper sequenced by an Illumina HiSeq X-Ten and PacBio Bioscience Sequel platform. A total of 254 putative antimicrobial peptide (AMP) genes were identified, which can be divided into 34 classes according to the annotation of the Antimicrobial Peptides Database (APD3). Their locations in pseudochromosomes were also determined. Thrombin-, lectin-, and scolopendin-derived putative AMPs were the three largest parts. In addition, expressions of putative AMPs were measured by our transcriptome data. Two putative AMP genes (gapdh1 and gapdh2) were involved in glycolysis, which had extremely high expression levels in giant grouper muscle. As it has been reported that AMPs inhibit the growth of a broad spectrum of microbes and participate in regulating innate and adaptive immune responses, genome sequencing of this study provides a comprehensive cataloging of putative AMPs of groupers, supporting antimicrobial research and aquaculture therapy. These genomic resources will be beneficial to further molecular breeding of this economically important fish. [ABSTRACT FROM AUTHOR]

We presented the complete mitochondrial genome of theEpinephelus moarain this study. The mitochondrial genome is 16,696 bp long and consists of 13 protein-coding genes, two rRNA genes, 22 tRNA genes and a control region. The gene order and composition ofEpinephelus tukulamitochondrial genome was similar to that of most other vertebrates. The nucleotide compositions of the light strand are 26.45% of A, 16.09% of C, 28.60% of T and 28.86% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM PUBLISHER]

The complete mitochondrial genome of theEpinephelus akaarawas presented in this study. The mitochondrial genome is 16,743 bp long and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. The gene order and composition ofEpinephelus akaaramitochondrial genome was similar to that of most other vertebrates. The nucleotide compositions of the light strand are 27.31% of A, 16.20% of C, 28.68% of T and 27.81% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM PUBLISHER]

The complete mitochondrial genome of theEpinephelus lanceolatuswas presented in this study. The mitochondrial genome is 16,743 bp long and consists of 13 protein-coding genes, two rRNA genes, 22 tRNA genes and a control region. The gene order and composition ofE. lanceolatusmitochondrial genome was similar to that of most other vertebrates. The nucleotide compositions of the light strand are 26.55% of A, 15.02% of C, 29.67% of T and 28.76% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM PUBLISHER]

The complete mitochondrial genome of theDrepane punctatawas presented in our study. The mitochondrial genome is 16,397 bp long and consists of 13 protein-coding genes, two rRNA genes, 16 tRNA genes and a control region. The gene order and composition ofD. punctatamitochondrial genome was different from that of most other vertebrates. The nucleotide compositions of the light strand are 24.56% of A, 16.02% of C, 27.81% of T and 31.61% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and five tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM PUBLISHER]

The complete mitochondrial genome of theRhabdosargus sarbawas presented in our study. The mitochondrial genome is 16,644 bp long and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. The gene order and composition ofR. sarbamitochondrial genome was similar to that of most other vertebrates. The nucleotide compositions of the light strand are 27.01% of A, 17.96% of C, 26.02% of T and 29.01% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM PUBLISHER]

The complete mitochondrial genome of thePiaractus brachypomusis described in the present study. The mitochondrial genome is 16,561 bp long and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. TheP. brachypomusmitochondrial genome shows the similar gene order and composition with those of most other vertebrates. The nucleotide compositions of the light strand in descending order is 31.57% of A, 26.19% of C, 26.18% of T and 16.06% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of thePampus nozawaewas presented in this study. The mitochondrial genome is 16,556 bp long and consists of 13 protein-coding genes, two rRNA genes, 22 tRNA genes and a control region. The gene order and composition ofPampus nozawaemitochondrial genome was similar to that of most other vertebrates. The nucleotide compositions of the light strand are 30.01% of A, 27.51% of C, 27.29% of T and 15.18% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and seven tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM AUTHOR]

We presented the complete mitochondrial genome of thePlatax teirain this study. The mitochondrial genome is 16,561 bp long and consists of 13 protein-coding genes, two rRNA genes, 22 tRNA genes and a control region. The gene order and composition ofEpinephelus tukulamitochondrial genome was similar to that of most other vertebrates. The nucleotide compositions of the light strand are 28.80% of A, 31.16% of C, 24.44% of T and 15.60% of G. With the exception of the NADH dehydrogenase subunit 6 (ND6) and seven tRNA genes, all other mitochondrial genes are encoded on the heavy strand. [ABSTRACT FROM AUTHOR]

In this study, we systematically investigated the process of sex reversal induced by 17-methyltestosterone (MT) feeding and MT-feeding withdrawal at the ovary differentiation stage in orange-spotted groupers, Epinephelus coioides. Gonadal histology showed that MT feeding induced a precocious sex reversal from immature ovaries to testes, bypassing the formation of an ovarian cavity, and MT-feeding withdrawal led to an ovarian fate. In both the MT feeding and MT-feeding withdrawal phases, cytochrome P450 family 11 subfamily B (cyp11b) gene expression and serum 11-KT levels were not significantly changed, suggesting that the MT-treated fish did not generate endogenous steroids, even though active spermatogenesis occurred. Finally, by tracing doublesex-expressing and Mab-3-related transcription factor 1 (dmrt1)-expressing cells and TUNEL (terminal deoxynucleotidyl transferase 2-deoxyuridine, 5-triphosphate nick end labeling) assays, we found that the efferent duct formed first, and then, the germ cells and somatic cells of the testicular tissue were generated around the efferent duct during MT-feeding-induced precocious sex reversal. Collectively, our findings provide insights into the molecular and cellular mechanisms underlying sex reversal induced by exogenous hormones during sex differentiation in the protogynous orange-spotted grouper. [ABSTRACT FROM AUTHOR]