Two IFNa3s mediate the regulation of IRF9 in the process of infection with Streptococcus iniae in yellowfin seabream, Acanthopagrus latus (Hottuyn, 1782)

IRF9 can play an antibacterial role by regulating the type I interferon (IFN) pathway. Streptococcus iniae can cause many deaths of yellowfin seabream, Acanthopagrus latus in pond farming. Nevertheless, the regulatory mechanism of type I IFN signalling by A. latus IRF9 (AlIRF9) against S. iniae remains elucidated. In our study, AlIRF9 has a total cDNA length of 3200 bp and contains a 1311 bp ORF encoding a presumed 436 amino acids (aa). The genomic DNA sequence of AlIRF9 has nine exons and eight introns, and AlIRF9 was expressed in various tissues, containing the stomach, spleen, brain, skin, and liver, among which the highest expression was in the spleen. Moreover, AlIRF9 transcriptions in the spleen, liver, kidney, and brain were increased by S. iniae infection. By overexpression of AlIRF9, AlIRF9 is shown as a whole-cell distribution, mainly concentrated in the nucleus. Moreover, the promoter fragments of -415 to +192 bp and -311 to +196 bp were regarded as core sequences from two AlIFNa3s. The point mutation analyses verified that AlIFNa3 and AlIFNa3-like transcriptions are dependent on both M3 sites with AlIRF9. In addition, AlIRF9 could greatly reduce two AlIFNa3s and interferon signalling factors expressions. These results showed that in A. latus, both AlIFNa3 and AlIFNa3-like can mediate the regulation of AlIRF9 in the process of infection with S. iniae.

Identification of the NOD-like receptor family of golden pompano and expression in response to bacterial and parasitic exposure reveal its key role in innate immunity

This study presents a genome-wide identification of NOD-like receptors (NLRs) in the golden pompano, key to its innate immunity. We identified 30 ToNLRs, analyzing their chromosomal positions, characteristics, evolutionary relationships, evidence of positive selection, and synteny with the yellowtail kingfish. Our findings categorize these NLRs into three main subgroups: NLRA, NLRC, and the distinct ToNLRX1. Post-exposure to Streptococcus agalactiae, most ToNLRs increased expression in the spleen, whereas NLRC3like13, NLRC3like16, and NLRC3like19 so in the kidneys. Upon Cryptocaryon irritans exposure, we categorized our groups based on the site of infection into the control group (BFS), the trophont-attached skin (TAS), and the nearby region skin (NRS). ToAPAF1 and ToNOD1 expressions rose in the NRS, in contrast to decreased expressions of ToNLRC5, ToNWD1 and ToCIITA. Other ToNLRs showed variable expressions in the TAS. Overall, this research lays the groundwork for further exploration of innate immunity in the golden pompano.

Genome-wide identification of heat shock protein gene family and their responses to pathogen challenge in Trachinotus ovatus

Heat Shock Proteins (HSPs) are a widely distributed family of proteins produced in response to heat and other stresses. To develop a deeper understanding of the mechanisms governing expression of HSPs in the bony fish Trachinotus ovatus, we carried out a whole genome analysis and identified 43 HSP genes. Based on their phylogenetic relationships with Danio rerio, Seriola dumerili, and Seriola lalandi, they were divided into four subfamilies: HSP20, HSP60, HSP70, and HSP90. We performed an analysis of the predicted physicochemical properties and subcellular localization of proteins encoded by these genes. The chromosomal localization results showed that the HSP genes are distributed across 20 chromosomes of T. ovatus.These genes were found to be expressed in different tissues, and they showed differential expression in the immune response against Streptococcus agalactiae. However, there was no significant differential expression in the different skin tissue locations of T. ovatus after infection by Cryptocaryon irritans Brown. This study provides basic information for further research on the evolution and structure and function of HSPs in teleosts.

Cryopreservation of black seabream (Acanthopagrus schlegelii) sperm

In recent years, biotechnology has had a significant impact on the aquaculture industry, particularly in the field of breeding. Molecular selection breeding has emerged as a novel approach to breeding. Reducing the cost of genetic information for individuals with desirable traits after breeding has become an important research direction. Cryopreservation technology allows bypassing time and space constraints in genetic breeding, simplifying broodstock management. This study presents a detailed cryopreservation method for black seabream sperm, evaluating extender type, glucose concentration, cryoprotectant type and concentration, sperm-dilution ratio, and cooling protocols. Sperm motility parameters were analyzed using computer-assisted sperm analysis (CASA) before and after two days of freezing. This involved using an RS solution with a glucose concentration of 15 g/L and adding a 5% final concentration of EG as the sperm cryoprotectant. After mixing the sperm and solution at a ratio of 1:2, we subjected it to 5 min fumigation at 5 cm above the liquid nitrogen surface before plunging it into the nitrogen. Sperm motility reached 85.46 ± 7.32% after two days. Various enzymatic activities showed changes over 20 days post-cryopreservation. This improved cryopreservation protocol for black seabream sperm is beneficial for genetic breeding and reproduction and provides reference for studying the cryodamage mechanisms of black seabream sperm.

Molecular characterization of TNF-β and IFN-γ in yellowfin seabream (Acanthopagrus latus, Hottuyn, 1782) and their immune responses to density stress during transport

The inflammatory cytokines TNF-β and IFN-γ are important mediators of the vertebrate inflammatory response and coordinators of the immune system in regard to NF-κB signalling pathways. In this study, the TNF-β and IFN-γ genes of yellowfin seabream, Acanthopagrus latus were identified, and the multiple sequence alignments, evolutionary relationships and gene expressions of the two genes were also determined. AlTNF-β contained a 762 bp open reading frame (ORF) encoding 253 amino acids, while AlIFN-γ contained a 582 bp ORF encoding 193 amino acids. An amino-acid sequence alignment analysis showed that these proteins have highly conserved transmembrane structural domains among teleosts. Moreover, AlTNF-β has a close affinity with TNF-β of yellowfin seabream while AlIFN-γ has a high evolutionary correlation with A. regius and Sparus aurata. In addition, the mRNAs of AlTNF-β and AlIFN-γ are widely expressed in various tissues. AlTNF-β is highly expressed in gill and intestinal tissues, and the mRNA levels of AlIFN-γ are higher in spleen, skin, and gill tissues than in other tissues. Under transportation density stress, the mRNA level of AlTNF-β was significantly elevated in the intestine of the high-density group, while AlTNF-β transcription in the gills did not vary significantly among the density groups. Furthermore, AlIFN-γ expression was increased in liver, intestinal, and gill tissues under high transportation density. The results of this study show that TNF-β and IFN-γ expression in yellowfin seabream is greatly affected by density stress. The density of 125 per bag for 4-5 cm fry or 1200 per bag for 1-2 cm fry is most suitable for the transportation of live fish. These results might provide a reference for further studies on the immunomodulatory response process and auxiliary function of immune stress of TNF and IFN genes in fish under density stress.

Genome-Wide Identification of Trachinotus ovatus Antimicrobial Peptides and Their Immune Response against Two Pathogen Challenges

Golden pompano, Trachinotus ovatus, as a highly nutritious commercially valuable marine fish, has become one of the preferred species for many fish farmers due to its rapid growth, wide adaptability, and ease of feeding and management. However, with the expansion of aquaculture scale, bacterial and parasitic diseases have also become major threats to the golden pompano industry. This study, based on comparative genomics, shows the possibility of preferential evolution of freshwater fish over marine fish by analyzing the phylogenetic relationships and divergence times of 14 marine fish and freshwater fish. Furthermore, we identified antimicrobial peptide genes from 14 species at the genomic level and found that the number of putative antimicrobial peptides may be related to species evolution. Subsequently, we classified the 341 identified AMPs from golden pompano into 38 categories based on the classification provided by the APD3. Among them, TCP represented the highest proportion, accounting for 23.2% of the total, followed by scolopendin, lectin, chemokine, BPTI, and histone-derived peptides. At the same time, the distribution of AMPs in chromosomes varied with type, and covariance analysis showed the frequency of its repeat events. Enrichment analysis and PPI indicated that AMP was mainly concentrated in pathways associated with disease immunity. In addition, our transcriptomic data measured the expression of putative AMPs of golden pompano in 12 normal tissues, as well as in the liver, spleen, and kidney infected with Streptococcus agalactiae and skin infected with Cryptocaryon irritans. As the infection with S. agalactiae and C. irritans progressed, we observed tissue specificity in the number and types of responsive AMPs. Positive selection of AMP genes may participate in the immune response through the MAPK signaling pathway. The genome-wide identification of antimicrobial peptides in the golden pompano provided a complete database of potential AMPs that can contribute to further understanding the immune mechanisms in pathogens. AMPs were expected to replace traditional antibiotics and be developed into targeted drugs against specific bacterial and parasitic pathogens for more precise and effective treatment to improve aquaculture production.

The regulatory mechanisms of IRF7 mediated by the type I IFN signalling pathway against Streptococcus iniae in yellowfin seabream, Acanthopagrus latus (Hottuyn, 1782)

Interferon regulatory factor 7 (IRF7) regulates type I interferon (IFN) genes via combining to the ISRE region in the immune response against bacteria. Streptococcus iniae is one of the dominant pathogenic bacteria of yellowfin seabream, Acanthopagrus latus. However, the regulatory mechanisms of A. latus IRF7 (AlIRF7) mediated by the type I IFN signalling pathway against S. iniae was ambiguously. In the present study, IRF7, and two IFNa3s (IFNa3 and IFNa3-like) were authenticated from A. latus. The total length of AlIRF7 cDNA is 2142 bp, containing a 1314 bp open reading frame (ORF) encoding an inferred 437 amino acids (aa). Three typical regions, a serine-rich domain (SRD), a DNA-binding domain (DBD), and an IRF association domain (IAD), are conserved in AlIRF7. Furthermore, AlIRF7 is fundamentally expressed in various kinds of organs, with high levels in the spleen and liver. Additionally, S. iniae challenge promoted AlIRF7 expression in the spleen, liver, kidney, and brain. AlIRF7 is confirmed to be located at the nucleus and cytoplasm by overexpression of AlIRF7. Moreover, truncation mutation analyses shows that the regions, -821 bp to +192 bp and -928 bp to +196 bp, were known as core promoters from AlIFNa3 and AlIFNa3-like, respectively. The point mutation analyses and electrophoretic mobile shift assay (EMSA) verified that AlIFNa3 and AlIFNa3-like transcriptions are depended on the M2/5 and M2/3/4 binding sites with AlIRF7 regulation, respectively. Additionally, an overexpression experiment showed that AlIRF7 can dramatically decrease the mRNA levels of two AlIFNa3s and interferon signalling molecules. These results suggest that two IFNa3s may mediate the regulation of AlIRF7 in the immune responses of A. latus against S. iniae infection.

Transcriptomics Reveal the Effects of Breeding Temperature on Growth and Metabolism in the Early Developmental Stage of Platax teira

The growth, development, and survival of fish, especially in the early stages of development, is influenced by a complex of environmental factors, among which temperature is one of the most important. Although the physiological effects of environmental stress in fish have been extensively studied, the molecular mechanisms are poorly understood. However, recent advances in transcriptomic techniques have facilitated the study of the molecular mechanisms of environmental stress responses in aquatic species. Here, we aimed to elucidate the effects of breeding temperatures (21, 24, 27, and 30 °C) on the growth and nutrient metabolism in the early developmental stage of Platax teira, using transcriptomic techniques. Transcriptomic analysis identified 5492, 6937, and 4246 differentially expressed genes (DEGs) in the 21 vs. 24 °C, 27 vs. 24 °C, and 30 vs. 24 °C comparisons, respectively, most of which were involved in cell processes, single organism, metabolism, catalytic activity, and cell part, based on gene ontology (GO) functional annotations. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the DEGs were mainly enriched in pathways related to metabolism of matter and energy, protein digestion and absorption, and glucose and lipid metabolism. Additionally, the expression of genes related to energy, lipid, and glucose metabolism in the fish liver was upregulated under a low-temperature condition (21 °C), although increasing the temperature within the acceptable threshold improved nutrient metabolism and growth in the fish. Meanwhile, nutrient metabolism and growth were suppressed by an extremely high temperature (30 °C) owing to oxidative stress. Overall, it was shown that nutrient metabolism pathways were involved in thermal stress responses in P. teira, and the optimal breeding temperature range was 24-27 °C. Through transcriptomics, the regulatory mechanism of larval development in P. teira under different growth temperatures was elucidated, with the goal of establishing a theoretical basis for industrial breeding.

Characterization of the MMP9 Gene and Its Association with Cryptocaryon irritans Resistance Traits in Trachinotus ovatus (Linnaeus, 1758)

The MMPs are endogenous proteolytic enzymes that require zinc and calcium as cofactors. MMP9 is one of the most complex matrix metalloproteinases in the gelatinase family and has many biological functions. In mammals, mmp9 is thought to be closely associated with cancer. However, studies in fish have rarely been reported. In this study, to understand the expression pattern of the ToMMP9 gene and its association with the resistance of Trachinotus ovatus to Cryptocaryon irritans, the sequence of the MMP9 gene was obtained from the genome database. The expression profiles were measured by qRT-PCR, the SNPs were screened by direct sequencing, and genotyping was performed. The ToMMP9 gene contained a 2058 bp ORF encoding a putative amino acid sequence of 685 residues. The homology of the ToMMP9 in teleosts was more than 85%, and the genome structure of ToMMP9 was conserved in chordates. The ToMMP9 gene was expressed in different tissues of healthy individuals and was highly expressed in the fin, the gill, the liver and the skin tissues. The ToMMP9 expression in the skin of the infected site and its adjacent sites increased significantly after C. irritans infection. Two SNPs were identified in the ToMMP9 gene, and the SNP (+400A/G) located in the first intron was found to be significantly associated with the susceptibility/resistance to C. irritans. These findings suggest that ToMMP9 may play an important role in the immune response of T. ovatus against C. irritans.

Characteristics of microplastic pollution in golden pompano (Trachinotus ovatus) aquaculture areas and the relationship between colonized-microbiota on microplastics and intestinal microflora

Microplastic (MPs) pollution is a global marine environmental problem. The effects of MPs on the gut microbiota of aquatic organisms have received considerable attention. For example, microbes colonizing MPs in pond cultures alter the structure and function of the intestinal microbes of shrimp and fish. It was hypothesized that bacteria on MPs in natural mariculture areas also interact with the intestinal flora of golden pompano (Trachinotus ovatus) because biofilms can form on the surface of MPs during long-term floating in seawater. To our knowledge, this study is the first to investigate MPs pollution in T. ovatus aquaculture. DNA sequencing and bioinformatics analysis confirmed the effect of microbial colonization of MPs on the intestinal flora of T. ovatus. The MPs detected in the gut wet weight (w.w.) of golden pompano (546 ± 52 items/g) were mainly pellets and fragments of blue or green, whereas the sediment MPs dry weight (d.w.) (4765 ± 116 items/kg) were mainly black fibers. The MPs richness in the sediment gradually increased from the open-sea aquaculture area to the estuarine aquaculture area and was positively correlated with the MPs richness in the intestinal tract of golden pompano. MPs 20-200 μm were the most common in the gut and sediment. The intake of MPs increased the abundance of Proteobacteria and decreased that of Firmicutes in the intestinal flora. The functional compositions of MP-colonizing microbes and gut microbiota were similar, suggesting that the two communities influence each other. Network analysis further confirmed this and revealed that Vibrio plays a key role in the intestinal flora and surface microorganisms of MPs. Overall, the intake of MPs by aquatic animals not only affects the intestinal flora and intestinal microbial function, but also poses potential risks to aquaculture.

Baseline Findings of PreventE4: A Double-Blind Placebo Controlled Clinical Trial Testing High Dose DHA in APOE4 Carriers before the Onset of Dementia

INTRODUCTION

Lower blood levels of the omega-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) are correlated with worse cognitive functions, particularly among APOE ε4 carriers. Whether DHA supplementation in APOE ε4 carriers with limited DHA consumption and dementia risk factors can delay or slow down disease progression when started before the onset of clinical dementia is not known.

METHODS

PreventE4 is a double-blind, single site, randomized, placebo-controlled trial in cognitively unimpaired individuals with limited omega-3 consumption and dementia risk factors (n=368). Its objectives are to determine (1) whether carrying the APOE ε4 allele is associated with lower delivery of DHA to the brain; and (2) whether high dose DHA supplementation affects brain imaging biomarkers of AD and cognitive function.

RESULTS

365 cognitively unimpaired individuals between 55 and 80 (mean age 66) were randomized to 2 grams of DHA per day or identically appearing placebo for a period of 2 years. Half the participants were asked to complete lumbar punctures at baseline and 6-month visits to obtain cerebrospinal fluid (CSF). The primary trial outcome measure is the change in CSF DHA to arachidonic acid ratio after 6 months of the intervention (n=181). Secondary trial outcomes include the change in functional and structural connectivity using resting state functional MRI at 24 months (n=365). Exploratory outcomes include the change in Repeatable Battery of the Assessment of Neuropsychological Status at 24 months (n=365).

CONCLUSIONS

Findings from PreventE4 will clarify the brain delivery of DHA in individuals carrying the APOE ε4 allele with implications for dementia prevention strategies. Trial was registered as NCT03613844.

Effects of cysteine addition to low-fishmeal diets on the growth, anti-oxidative stress, intestine immunity, and Streptococcus agalactiae resistance in juvenile golden pompano (Trachinotus ovatus)

As the precursor of taurine, cysteine serves physiological functions, such as anti-oxidative stress and immune improvement. Investigation of cysteine and its derivatives has made positive progress in avian and mammalian species, yet the study and application of cysteine in aquatic animals are relatively rare. Therefore, we evaluated the effects of supplementing a low-fishmeal diet with various levels of cysteine on the growth, antioxidant capacity, intestine immunity, and resistance against Streptococcus agalactiae of the juvenile golden pompano (Trachinotus ovatus). According to our study, exogenous supplementation with 0.6-1.2% cysteine greatly increased the final body weight (FBW) and specific growth rate (SGR) of golden pompano compared to the control group. Under the present conditions, the optimum dietary cysteine supplementation level for golden pompano was 0.91% based on the polynomial regression analysis of SGR. Meanwhile, we found that the Nrf2/Keap1/HO-1 signaling pathway was notably upregulated with the increase of exogenous cysteine, which increased antioxidant enzyme activity in serum and gene expression in the intestine and reduced the level of reactive oxygen species (ROS) in the serum of golden pompano. In addition, morphological analysis of the midgut demonstrated that exogenous cysteine improved muscle thickness and villi length, which suggested that the physical barrier of the intestine was greatly strengthened by cysteine. Moreover, cysteine increased the diversity and relative abundance of the intestinal flora of golden pompano. Cysteine suppressed intestinal NF-κB/IKK/IκB signaling and pro-inflammatory cytokine mRNA levels. Conversely, intestinal anti-inflammatory cytokine gene expression and serum immune parameters were upregulated with the supplementary volume of cysteine and improved intestine immunity. Further, exogenous cysteine supplementation greatly reduced the mortality rate of golden pompano challenged with S. agalactiae. In general, our findings provide more valuable information and new insights into the rational use of cysteine in the culture of healthy aquatic animals.

Effects of exogenous taurine supplementation on the growth, antioxidant capacity, intestine immunity, and resistance against Streptococcus agalactiae in juvenile golden pompano (Trachinotus ovatus) fed with a low-fishmeal diet

Taurine has various biological functions in fish, playing an essential role in growth, resistance to oxidative stress, and intestine immunity. Here, we evaluated the effects of exogenous taurine added to low-fishmeal diets on the growth, anti-oxidative stress, intestine immunity, and Streptococcus agalactiae resistance in juvenile golden pompano (Trachinotus ovatus). Our study showed that exogenous taurine supplementation of 1.2% (T3 group) greatly enhanced the weight gain rate and specific growth rate (SGR) of juvenile golden pompano, significantly upregulating growth-related factor expression in the brain and liver, as well as the levels of growth-related parameters in the serum. Polynomial regression analysis using SGR estimated the optimal dietary taurine level for golden pompano at 1.18%. Moderate exogenous taurine also increased the muscular thickness and villus length within the intestine, maintained intestinal physical barrier stability, activated the Nrf2/Keap-1/HO-1 signaling pathway, increased intestinal antioxidant enzyme gene expression and antioxidant enzyme activity in the serum, and upregulated immunoglobulin and complement levels in parallel with declining reactive oxygen species (ROS) levels in the serum. Antioxidant factor expression was also upregulated in the intestine. Furthermore, supplementation suppressed NF-κB signaling and intestinal pro-inflammatory cytokine gene expression, increased anti-inflammatory cytokine gene expression, and improved intestine immunity. Finally, taurine supplementation improved the survival rate of golden pompano challenged with S. agalactiae. Overall, our findings provide additional information and support for the rational use of taurine in healthy aquatic animal farming.

Detection and identification of marine fish mislabeling in Guangzhou's supermarkets and sushi restaurants using DNA barcoding

In this study, DNA barcoding was applied to identify the distinct species of fish products in Guangzhou supermarkets and sushi restaurants in order to confirm whether products were correctly labeled. Samples were analyzed using mitochondrial cytochrome C oxidase subunit I (CO I) gene as the target. Our results showed that the CO I gene of all 139 samples examined was successfully amplified by PCR. When sequenced, 30 samples (21.58%) were mislabeled as the wrong species, 11 samples had insufficient information provided on the label to determine if the labeling was correct (7.91%), and four samples failed sequencing (2.88%). We also found that the use of proper labels for fish products in sushi restaurants was higher than that in supermarkets. As a simple, rapid, and efficient technology, DNA barcoding can be widely used for species identification of fish products. Our work shows that regulation of the labeling of fish products, as we evaluated in Guangzhou and other markets in China, is needed on a global scale.

Effects of acute ammonia exposure and recovery on the antioxidant response and expression of genes in the Nrf2-Keap1 signaling pathway in the juvenile golden pompano (Trachinotus ovatus)

Continuous exposure to high levels of ammonia can cause oxidative damage to fish tissues and organs. To date, the mechanism by which juvenile golden pompano (Trachinotus ovatus) are poisoned by ammonia exposure has not been thoroughly elucidated. although the mechanisms of ammonia toxicity are not well described for the pompano, many other studies presented these effects to other fish species. So an overview would be given. First, an acute ammonia nitrogen toxicity experiment on juvenile golden pompano obtained a 96-h half-lethal concentration (96 h LC50) of 26.9 mg/L. In the ammonia exposure experiment, fish were sampled at 0 h, 6 h, 12 h, 24 h, 48 h, 72 h and 96 h after exposure to ammonia water (26.93 mg/L). The results showed that with the prolonged ammonia nitrogen exposure, plasma cortisol (COR), total cholesterol (TC), glutamic-pyruvic transaminase (ALT), glutamic oxalacetic transaminase (AST) and malonaldehyde (MDA) levels continued to rise, while glucose (GLU) levels first increased and later gradually decreased after 12 h. The activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in the liver and the mRNA expression levels of antioxidant genes (SOD, CAT, and GPX) first increased and subsequently decreased with increasing exposure time. Through microscopic observation, it was found that the degree of liver damage increased with increasing stress time and was most serious at 96 h. In the post-poison recovery experiment, the fish exposed to ammonia were transferred to clean water, and samples were taken at 24 h, 48 h, 72 h and 96 h after recovery. The results showed that with the increasing recovery time, each index recovered to the initial level to varying degrees, but the recovery time of 96 h was not enough for the fish to return to the normal level. We also examined the regulation of the Nrf2-Keap1 signaling pathway by the molecular mechanism of the antioxidant defense system. The results of this analysis showed that there was a positive correlation between Nrf2 and liver antioxidant gene expression levels, while there was a negative correlation between Keap1 and liver antioxidant gene expression levels, which may be observed because Nrf2 plays a key role in inducing antioxidant genes, and Keap1 may hinder the response to Nrf2. These results may provide a deeper and more comprehensive understanding of the impact of ammonia exposure on fish and help to provide a foundation for managing the healthy reproduction of juvenile fish.

Gill oxidative damage caused by acute ammonia stress was reduced through the HIF-1α/NF-κb signaling pathway in golden pompano (Trachinotus ovatus)

This study aimed to investigate the intoxication mechanism of golden pompano (Trachinotus ovatus) exposed to high ammonia levels and the effects on the immune and antioxidant mechanisms of gills. Juvenile golden pompano was exposed to ammonia (total ammonia: 26.9 mg/L) to induce 96 h of ammonia stress, and a 96 h recovery experiment was performed after poisoning. Then, we evaluated hematological parameters, the histological structure and the expression of related genes. In this experiment, continuous exposure to high levels of ammonia led to a significant increase in plasma alkaline phosphatase (ALP), acid phosphatase (ACP) and lactate dehydrogenase (LDH) levels (P < 0.05), and the levels of triiodothyronine (T3) and tetraiodothyronine (T4) were significantly reduced (P < 0.05). Moreover, the expression of antioxidant genes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and inflammatory cytokines such as tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) increased (P < 0.05). These results indicate that ammonia activates the active osmotic regulatory mechanism of fish gills and participates in defense and immune responses. However, with prolonged exposure to ammonia, the balance of the defense system is disrupted, leading to oxidative damage and inflammation of the gill tissue. This research not only helps elucidate the intoxication mechanism of golden pompano by ammonia at the molecular level but also provides a theoretical basis for further research on detoxification mechanisms.

A chromosome-level genome assembly of the yellowfin seabream (Acanthopagrus latus; Hottuyn, 1782) provides insights into its osmoregulation and sex reversal

The yellowfin seabream Acanthopagrus latus is the economically most important Sparidae fish in the northern South China Sea. As euryhaline fish, they are perfect model for investigating osmoregulatory mechanisms in teleosts. Moreover, the reproductive biology of hermaphrodites has long been intriguing; however, little information is known about the molecular pathways underlying their sex change. Here, we report a chromosome level reference genome of A. latus generated by employing the PacBio single molecule sequencing technique (SMRT) and high-throughput chromosome conformation capture (Hi-C) technologies. The draft genome of yellowfin seabream was 806 Mb, with 732 Mb scaffolds anchored on 24 chromosomes. The contig N50 and scaffold N50 were 2.6 Mb and 30.17 Mb, respectively. The assembly is of high integrity and includes 92.23% universal single-copy orthologues based on benchmarking universal single-copy orthologs (BUSCO) analysis. A total of 19,631 protein-coding genes were functionally annotated in the reference genome. Moreover, ARRDC3 and GSTA gene families which related to osmoregulation underwent an extensive expansion in two euryhaline sparids fish genomes compared to other teleost genomes. Moreover, integrating sex-specific transcriptome analyses, several genes related to the transforming growth factor beta (TGF-β) signalling pathway involved in sex differentiation and development. This genomic resource will not only be valuable for studying the osmoregulatory mechanisms in estuarine fish and sex determination in hermaphrodite vertebrate species, but also provide useful genomic tools for facilitating breeding of the yellowfin seabream.

Functional characterization, tissue distribution and nutritional regulation of the Elovl4 gene in golden pompano, Trachinotus ovatus (Linnaeus, 1758)

The elongases of very long-chain fatty acids (Elovls) are involved in the rate-limiting of the carbon chain elongation reaction in fatty acid (FA) biosynthesis in vertebrates. One member of the Elovls family, Elovl4, has been regarded as a critical enzyme involved in the biosynthesis pathway of polyunsaturated fatty acids (PUFAs). To explore the role of Elovl4 in PUFA synthesis in Trachinotus ovatus, the cDNA of the Elovl4b gene is cloned from T. ovatus (ToElovl4b). The ORF of ToElovl4b was 918 bp and encoded 305 amino acid (aa) protein sequences. Sequence alignment showed that the deduced amino acids contained significant structural features of the Elovl4 family, such as a histidine box motif (HXXHH), multiple transmembrane domains and an endoplasmic reticulum (ER) retention signal. Moreover, phylogenetic analysis revealed that ToElovl4b was highly conserved with that of Rachycentron canadum Elovl4b. Moreover, heterologous expression in yeast demonstrated that ToElovl4b could efficiently elongate 18:2n-6, 18:3n-6 and 20:5n-3 FAs up to 20:2n-6, 20:3n-6 and 22:5n-3, respectively. Furthermore, the tissue expression profile indicated that mRNA expression of ToElovl4b was higher in the gonads and brain than in other tissues. Additionally, nutritional regulation suggested the highest mRNA levels of ToElovl4b in liver and brain were under feeding with 1:1 FO-SO (fish oil, FO; soybean oil, SO) and 1:1 FO-CO (corn oil, CO)), respectively. These new insights were useful for understanding the molecular basis and regulation of LC-PUFA biosynthesis in fish.

Characterization and functional analysis of liver-expressed antimicrobial peptide-2 (LEAP-2) from golden pompano Trachinotus ovatus (Linnaeus 1758)

The liver-expressed antimicrobial peptide-2 (LEAP-2) is an important component of the innate immune defense system and plays an important role in resisting the invasion of pathogenic microorganisms. In this study, LEAP-2 from golden pompano (Trachinotus ovatus) was characterized and its expression in response to Photobacterium damselae was investigated. The full-length LEAP-2 cDNA was 1758 bp, which comprised a 5'-UTR of 250 bp, an ORF of 321 bp, and a 3'-UTR of 1187 bp, encoding 106 amino acids. LEAP-2 consisted of a conserved saposin B domain and four conserved cysteines that formed two pairs of disulphide bonds. The genomic organization of LEAP-2 was also determined and shown to consisted of three introns and two exons. The predicted promoter region of ToLEAP-2 contained several putative transcription factor binding sites. Quantitative real-time (qRT-PCR) analysis indicated that LEAP-2 was ubiquitously expressed in all examined tissues, with higher mRNA levels observed in the muscle, liver, spleen, and kidney. After P. damselae stimulation, the expression level of LEAP-2 mRNA was significantly upregulated in various tissues of golden pompano. In addition, SDS-PAGE showed that the molecular mass of recombinant LEAP-2 expressed in pET-32a was approximately 23 kDa. The purified recombinant protein showed antibacterial activity against Gram-positive and Gram-negative bacteria. Luciferase reporters were constructed for five deletion fragments of different lengths from the promoter region (-1575 bp to +251 bp), and the results showed that L3 (-659 bp to +251 bp) presented the highest activity, and it was therefore defined as the core region of the LEAP-2 promoter. The seven predicted transcription factor binding sites were deleted by using PCR technology, and the results showed that the mutation of the USF transcription factor binding site caused the activity to significantly decrease. The results indicate that golden pompano LEAP-2 potentially exhibits antimicrobial effects in fish innate immunity.

Functional analysis of two MyoDs revealed their role in the activation of myomixer expression in yellowfin seabream (Acanthopagrus latus) (Hottuyn, 1782)

Myoblast determination protein (MyoD), a muscle-specific basic helix-loop-helix (bHLH) transcription factor, plays a pivotal role in regulating skeletal muscle growth and development. However, the regulation mechanism of MyoD has not been determined in marine fishes. In the present study, we isolated the MyoD1 (AlMyoD1) and MyoD2 (AlMyoD2) genomic sequences and analyzed the expression patterns in different tissues of yellowfin seabream (Acanthopagrus latus). The open reading frame (ORF) sequences of AlMyoD1 and AlMyoD2 encoded 297 and 271 amino acids possessing three common characteristic domains, respectively, containing a myogenic basic domain, a bHLH domain, and a ser-rich region (helix III). Phylogenetic and genome structure analyses exhibited classic phylogeny and highly conserved exon/intron architecture. Furthermore, the AlMyoD1 and AlMyoD2 transcription levels were higher in white muscle than in the other tissues. In order to further study AlMyoD function in muscle, promoter sequence analysis found that several E-box binding sites were present. Additionally, binding sites of Almyomixer involved in mammal myoblast fusion, which expression was also the highest in white muscle, were found in the promoter of AlMyoD. Pomoter activity assays further confirmed that both AlMyoD1 and AlMyoD2 can dramatically activate Almyomixer expression, and the AlMyoD1 M2 and AlMyoD2 M5 E-box binding sites were functionally important for Almyomixer transcription based on mutation analysis and electrophoretic mobile shift assays (EMSA). In summary, two MyoDs play a core role in Almyomixer regulation and may promote myofibre formation during muscle development and growth by regulating Almyomixer expression.

Functional characterization of NK-lysin in golden pompano Trachinotus ovatus (Linnaeus 1758)

NK-lysin is an important part of the innate immune defence system and plays an important role in resisting the invasion of pathogenic microorganisms. In this study, NK-lysin from golden pompano (Trachinotus ovatus) was characterized and its expression in response to Photobacterium damselae was investigated. The full-length NK-lysin cDNA was 731 bp, which comprised a 5'-UTR of 63 bp, an ORF of 444 bp, and a 3'-UTR of 224 bp, and encoded 147 amino acids; NK-lysin consisted of a conserved saposin B domain and six conserved cysteines that formed three pairs of disulfide bonds. The genomic organization of NK-lysin was also determined and the gene consisted of four introns and five exons. The predicted promoter region of ToNK-lysin contained several putative transcription factor binding sites. Quantitative real-time (qRT-PCR) analysis indicated that ToNK-lysin was ubiquitously expressed in all examined tissues; the highest mRNA levels were observed in the skin, kidney and intestine, while the lowest expression level was detected in the stomach. After P. damselae stimulation, the expression level of NK-lysin mRNA was significantly upregulated in various tissues of golden pompano. In addition, SDS-PAGE showed that the molecular mass of recombinant NK-lysin expressed in pGEX-6P-1 was approximately 37 kDa. The purified recombinant protein showed antibacterial activity against gram-positive and gram-negative bacteria. The results indicate that golden pompano NK-lysin has potential antimicrobial roles in fish innate immunity.

MultiplexSSR: A pipeline for developing multiplex SSR-PCR assays from resequencing data

Next-generation sequencing has greatly promoted the investigation of single nucleotide polymorphisms, while studies of simple sequence repeats are sharply decreasing. However, simple sequence repeats still present some advantages in conservation genetics. In this study, an end-to-end pipeline referred to as MultiplexSSR was established to develop multiplex PCR assays in batches with highly polymorphic simple sequence repeats for capillary platforms from resequencing data. The distribution of single sequence repeats in the genome, the error profiles of genotypes and allelotypes, and the increase in the allele length range depending on the number of individuals were investigated. A total of 98% of single sequence repeats presented lengths of less than 100 bp. The error rate of the genotyping and allelotyping of dimeric patterns was ten times higher than those for other patterns. The error rate of allelotyping was less than that of genotyping. The allele length range reached approximate saturation with 10 individuals. This pipeline uses allele numbers to select highly polymorphic loci, masks loci with variation, and applies in silico PCR to improve primer specificity. The application of the developed multiplex SSR-PCR assays validated the pipeline's robustness, showing higher polymorphism and stability for the developed simple sequence repeats and a lower cost for genotyping and providing low-depth resequencing data from less than a dozen individuals for the development of markers. This pipeline fills the gap between next-generation sequencing and multiplex SSR-PCR.

Structural and expression analysis of golden pompano Trachinotus ovatus IRF5 and its role in regulation of type I IFN

The interferon regulatory factor 5 (IRF5) is a mediator of the type I IFN signalling pathways, thereby playing a key role in innate immunity. However, the detailed mechanism through which IRF5 regulates type I IFN in fish remains unclearly. In the present study, we first describe the identification of IRF5 (ToIRF5) from golden pompano (Trachinotus ovatus) and its features at the genomic sequence and expression level. The genomic DNA sequence consists of eight exons and seven introns. The full-length ToIRF5 cDNA is composed of 2, 059 bp and encodes for 499 amino acid polypeptides. The putative protein sequence shares 66.3%-82.9% identity to fish IRF5 and possesses three representative conserved domains (a DNA-binding domain (DBD) at the N-terminus, an IRF-associated domain (IAD), and a virus-activated domain (VAD) at the C-terminus) and one highly variable domain (middle region (MR)). Furthermore, the ToIRF5 transcript is constitutively expressed in all examined tissues, with higher levels observed in the immune relevant tissues. The mRNA levels of ToIRF5 are increased by polyinosinic: polycytidylic acid [poly (I: C)], lipopolysaccharide (LPS) and flagellin stimulation in the immune- and nonimmune-related tissues. The subcellular localization indicates that ToIRF5 is mainly localized in the cytoplasm with or without poly (I: C) induction. In addition, to explore whether ToIRF5 is a modulator of ToIFNa3, promoter analysis is performed. The region from -200 bp to +1 bp is identified as the core promoter by different truncated mutants of ToIFNa3. Mutation analyse declares that the activity of the ToIFNa3-5 promoter significantly decreases after targeted mutation of M2 binding sites. Moreover, overexpression of ToIRF5 in vitro memorably aggrandizes the expression of some IFN/IRF-based signalling pathway genes. These results provide new insights into the roles of teleost IRF5 in transcriptional mechanisms of type I IFN in the immunity process.

Interferon regulatory factor 2 plays a positive role in interferon gamma expression in golden pompano, Trachinotus ovatus (Linnaeus 1758)

In fish, interferon (IFN) regulatory factor 2 (IRF2) is a regulator of the type I IFN-dependent immune response, thereby playing a crucial role in innate immunity. However, the specific mechanism by which IRF2 regulates type II IFN in fish remains unclear. In the present study, first, to analyse the potential role of golden pompano (Trachinotus ovatus) IRF2 (ToIRF2) in the immune response, the mRNA level of ToIRF2 was detected by quantitative real-time polymerase chain reaction (qRT-PCR) after parasite infection. ToIRF2 was upregulated at early time points in both local infection sites (skin and gill) and system immune tissues (liver, spleen, and head-kidney) after stimulation with Cryptocaryon irritans. Second, to investigate the modulation effect of ToIRF2 on type II IFN (interferon gamma, IFNγ) expression, a promoter analysis was performed using progressive deletion mutations of ToIFNγ. The expression level of IFNγ-5 was highest among the five truncated mutants in response to ToIRF2, indicating that the core promoter region was located from -189 bp to +120 bp, which included the IRF2 binding sites. Mutation analyses showed that the activity of the ToIFNγ promoter dramatically decreased after the targeted mutation of the M1, M2 or M3 binding sites. Additionally, electrophoretic mobile shift assay (EMSA) confirmed that IRF2 interacted with the M1 binding site in the ToIFNγ promoter region to dominate ToIFNγ expression. Finally, overexpressing ToIRF2 in vitro notably increased ToIFNγ and the transcription of several type II IFN/IRF-based signalling pathway genes. These results suggested that ToIRF2 might be involved in the host defence against C. irritans infection and contribute to a better understanding of the transcriptional mechanisms by which ToIRF2 regulates type II IFN in fish.

Growth, physiological, and molecular responses of golden pompano Trachinotus ovatus (Linnaeus, 1758) reared at different salinities

Golden pompano (Trachinotus ovatus) is a commercially important marine fish and is widely cultured in the coastal area of South China. Salinity is one of the most important environmental factors influencing the growth and survival of fish. The aims of this study are to investigate the growth, physiological, and molecular responses of juvenile golden pompano reared at different salinities. Juveniles reared at 15 and 25‰ salinity grew significantly faster than those reared at the other salinities. According to the final body weights, weight gain rate, and feed conversion ratio, the suitable culture salinity range was 15-25‰ salinity. The levels of branchial NKA activity showed a typical "U-shaped" pattern with the lowest level at 15‰ salinity, which suggested a lower energy expenditure on osmoregulation at this level of salinity. The results of this study showed that the alanine aminotransferase, aspartate aminotransferase, and cortisol of juveniles at 5‰ were higher than those of other salinity groups. Our results showed that glucose-6-phosphate dehydrogenase significantly increased at 5‰ and 35‰ salinity. Our study showed that osmolality had significant differences in each salinity group. GH, GHR1, and GHR2 had a wide range of tissue expression including the liver, intestine, kidneys, muscle, gills and brain. The expression levels of GH, GHR1 and GHR2 in the intestine, kidneys, and muscle at 15‰ salinity were significantly higher than those in other three salinity groups. Based on the growth parameters and physiological and molecular responses, the results of the present study indicated that the optimal salinity for rearing golden pompano was 21.36‰ salinity.

Functional characterization of IRF8 regulation of type II IFN in golden pompano (Trachinotus ovatus)

Interferon regulatory factor 8 (IRF8) increases type I IFN transcription levels by binding to IFN promoters, thereby playing a role in innate immunity. Nevertheless, the detailed mechanism through which IRF8 regulates type II IFN in fish remains ambiguous. In the present study, two genes from the golden pompano (Trachinotus ovatus), IRF8 (ToIRF8) and IFN gamma (ToIFNγ), were identified in the IFN/IRF-based signalling pathway. The full-length ToIRF8 cDNA was composed of 2,141 bp and encoded a 421 amino acid polypeptide; the genomic DNA was 2,917 bp in length and consisted of 8 exons and 7 introns. The putative protein showed the highest sequence identity (90-92%) with fish IRF8 and possessed a DNA-binding domain (DBD), an IRF-association domain (IAD) and a nuclear localization signal (NLS) motif consistent with those of IRF8 in other vertebrates. Furthermore, the ToIRF8 transcripts were expressed in all examined tissues of healthy fish, with higher levels observed in the central nervous and immune relevant tissues. They were upregulated by polyinosinic acid: polycytidylic acid [poly (I: C)], lipopolysaccharide (LPS) and flagellin treatments in the blood, liver, intestine and kidney. The results from assays of subcellular localization showed that ToIRF8 was localized to the cytoplasm. Moreover, to investigate whether ToIRF8 was a regulator of ToIFNγ, a promoter analysis was performed using progressive deletion mutations of ToIFNγ. The results indicated that the region from -601 bp to -468 bp includes the core promoter. Mutation analyses indicated that the activity of the ToIFNγ promoter significantly decreased after the targeted mutation of the M1-M3 binding sites. Additionally, overexpressed ToIRF8 in vitro notably increased the expression of several IFN/IRF-based signalling pathway genes. These results suggest that IRF8 is vital in the defence of T. ovatus against bacterial infection and contributes to a better understanding of the transcriptional mechanisms of ToIRF8 on type II IFN in fish.

The complete mitochondrial genome of Cheilinus oxycephalus (Perciformes: Labridae)

Cheilinus oxycephalus is a marine fish species, belonging to the family Labridae and naturally distributed in Indo-Pacific waters. We obtained the first complete mitochondrial genome of this species using next-generation sequencing technology. This genome is 17,698 bp, and contains 13 protein-coding genes, 2 rRNAs, 22 tRNAs, and a D-loop region. These genes are mostly encoded on the heavy strand except for ND6 and eight tRNA genes. The AT content is 52.32%. These characteristics are similar to other bony fish. This mitochondrial genome would be used as a resource for phylogenetic reconstruction.

Functional characterization of interferon regulatory factor 2 and its role in the transcription of interferon a3 in golden pompano Trachinotus ovatus (Linnaeus 1758)

Similar to mammals, fish possess interferon (IFN) regulatory factor 2 (IRF2)-dependent type I IFN responses. Nevertheless, the detailed mechanism through which IRF2 regulates type I IFNa3 remains largely unknown. In the present study, we first identified two genes from golden pompano (Trachinotus ovatus), IRF2 (ToIRF2) and IFNa3 (ToIFNa3), in the IFN/IRF-based signalling pathway. The open reading frame (ORF) sequence of ToIRF2 encoded 335 amino acids possessing four typical characteristic domains, including a conserved DNA-binding domain (DBD), an interferon association domain 2 (IAD2), a transcriptional activation domain (TAD), and a transcriptional repression domain (TRD). Furthermore, transcripts of ToIRF2 were significantly upregulated after stimulation by polyinosinic: polycytidylic acid [poly (I:C)], lipopolysaccharide (LPS) and flagellin in immune-related tissues (blood, liver, and head-kidney). Moreover, to investigate whether ToIRF2 was a regulator of ToIFNa3, promoter analysis was performed. The results showed that the region from -896 bp to -200 bp is defined as the core promoter using progressive deletion mutations of IFNa3. Additionally, ToIRF2 overexpression led to a clear time-dependent enhancement of ToIFNa3 promoter expression in HEK293T cells. Mutation analyses indicated that the activity of the ToIFNa3 promoter significantly decreased after targeted mutation of M4/5 binding sites. Electrophoretic mobile shift assays (EMSAs) verified that IRF2 interacted with the binding site of the ToIFNa3 promoter region to regulate ToIFNa3 transcription. Last, the promoter activity of ToIFNa3-2 was more responsive to treatment with poly (I:C) than LPS and flagellin. Furthermore, overexpression of ToIRF2 in vitro obviously increased the expression of several IFN/IRF-based signalling pathway genes after poly (I:C) abduction. In conclusion, the present study provides the first evidence of the positive regulation of ToIFNa3 transcription by ToIRF2 and contributes to a better understanding of the transcriptional mechanisms of ToIRF2 in fish.

Characterization of the complete mitochondrial genome sequence of orangeline wrasse Halichoeres hartzfeldii (Bleeker, 1852) with the phylogenetic relationships within the Labridae species

The mitogenome of Halichoeres hartzfeldii is 16,481 bp in length. It consists of 37 typical vertebrate mitochondrial genes including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA), 2 ribosomal RNA (rRNA) genes, and a control region (D-loop). The orientation and arrangement of these genes is similar to that of the other sequenced Labridae mitogenome. The overall base composition of the mitogenome of H. hartzfeldii is biased towards A +T content at 52.9%. Phylogenetic analysis based on 13 concatenated PCGs nucleotide sequences indicated that the genome of H. hartzfeldii is closely related to the genus Halichoeres.

Characterization of the complete mitochondrial genome of Squalus brevirostris (Squaliformes, Squalidae)

The complete mitochondrial genome sequence of Squalus brevirostri was determined using next-generation sequencing. The whole circular genome is 16,734 bp in length. It contains 37 genes including13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA genes (tRNA), and a control region (D-Loop). The overall nucleotide composition is A: 30.38%, T: 30.73%, G: 24.61%, and C: 14.27%, with an A + T content of 61.11%. The phylogenetic analysis suggested that S. brevirostris was closely related to Squalus montalbani.

A High-Density Genetic Linkage Map and QTL Mapping for Sex in Black Tiger Shrimp (Penaeus monodon)

The black tiger shrimp, Penaeus monodon, is important in both fishery and aquaculture and is the second-most widely cultured shrimp species in the world. However, the current strains cannot meet the market needs in various cultural environments, and the genome resources for P. monodon are still lacking. Restriction-site associated DNA sequencing (RADseq) has been widely used in genetic linkage map construction and in quantitative trait loci (QTL) mapping. We constructed a high-density genetic linkage map with RADseq in a full-sib family. This map contained 6524 single nucleotide polymorphisms (SNPs) and 2208 unique loci. The total length was 3275.4 cM, and the genetic distance was estimated to be 1.1 Mb/cM. The sex trait is a dichotomous phenotype, and the same interval was detected as a QTL using QTL mapping and genome-wide association analysis. The most significant locus explained 77.4% of the phenotype variance. The sex locus was speculated to be the same in this species based on the sequence alignments in Mozambique, India, and Hawaii populations. The constructed genetic linkage map provided a valuable resource for QTL mapping, genome assembly, and genome comparison for shrimp. The demonstrated common sex locus is a step closer to locating the underlying gene.

Molecular characterization of toll-like receptor 14 from golden pompano Trachinotus ovatus (Linnaeus, 1758) and its expression response to three types of pathogen-associated molecular patterns

Toll-like receptors (TLRs) play crucial roles in the host immune system, including recognizing invading pathogenic microbes and triggering immune reactions. Toll-like receptor 14 (TLR14) has been identified in several fish species, but its function requires further study. In this study, TLR14 (designed as ToTLR14) from golden pompano (Trachinotus ovatus), was characterized and investigated its expression responses to three types of pathogen-associated molecular patterns. The full-length ToTLR14 cDNA was 3191 bp, and the deduced protein consisted of 876 amino acids. The ToTLR14 protein included 5 leucine rich repeat (LRR) domains, a C-terminal LRR domain in the extracellular region, a transmembrane domain and a Toll/interleukin (IL)-1 receptor (TIR) domain in the cytoplasmic region, which fits with the typical TLR domain architecture. The genomic organization of ToTLR14 was also identified and consisted of four introns and five exons. The predicted promoter region of ToTLR14 contained several putative transcription factor binding sites. Phylogenetic analysis showed that ToTLR14 was clustered into the TLR1 subfamily clade. Quantitative real-time (qRT-PCR) analysis indicated that ToTLR14 were ubiquitously expressed in all examined tissues, with higher mRNA levels observed in the skin, kidney and intestine, while the lowest level was detected in the stomach. After injection with polyinosinic:polycytidylic acid [poly(I:C)], flagellin or lipopolysaccharides (LPS), the expression level of ToTLR14 mRNA were significantly upregulated in various tissues of golden pompano. These results indicate that ToTLR14 may play an important role in systemic as well as mucosal defence after viral and bacterial stimulation.

Identification of Fatty Acid Desaturase 6 in Golden Pompano Trachinotus Ovatus (Linnaeus 1758) and Its Regulation by the PPARαb Transcription Factor

Fatty acid desaturases are rate-limiting enzymes in long-chain polyunsaturated fatty acid biosynthesis. The transcription factor peroxisome proliferator-activated receptor alpha b (PPARαb) regulates lipid metabolism in mammals, however, the mechanism whereby PPARαb regulates fatty acid desaturases is largely unknown in fish. In this study, we report the full length cDNA sequence of Trachinotus ovatus fatty acid desaturase, which encodes a 380 amino acid polypeptide, possessing three characteristic histidine domains. Phylogenetic and gene exon/intron structure analyses showed typical phylogeny: the T. ovatus fatty acid desaturase contained a highly conserved exon/intron architecture. Moreover, functional characterization by heterologous expression in yeast indicated that T. ovatus desaturase was a fatty acid desaturase, with Δ4/Δ5/Δ8 Fad activity. Promoter activity assays indicated that ToFads6 desaturase transcription was positively regulated by PPARαb. Similarly, PPARαb RNA interference decreased ToPPARαb and ToFads6 expression at the mRNA and protein levels in a time-dependent manner. Mutation analyses showed that the M2 binding site of PPARαb was functionally important for protein binding, and transcriptional activity of the ToFads6 promoter was significantly decreased after targeted mutation of M2. Electrophoretic mobile shift assays confirmed that PPARαb interacted with the binding site of the ToFads6 promoter region, to regulate ToFads6 transcription. In summary, PPARαb played a vital role in ToFads6 regulation and may promote the biosynthesis of long-chain polyunsaturated fatty acids by regulating ToFads6 expression.

The Transcriptional Factor PPARαb Positively Regulates Elovl5 Elongase in Golden Pompano Trachinotus ovatus (Linnaeus 1758)

The nuclear peroxisome proliferator-activated receptors (PPARs) regulate the transcription of elongases of very long-chain fatty acids (Elovl), which are involved in polyunsaturated fatty acid (PUFA) biosynthesis in mammals. In the present study, we first characterized the function of Elovl5 elongase in Trachinotus ovatus. The functional study showed that ToElovl5 displayed high elongation activity toward C18 and C20 PUFA. To investigate whether PPARαb was a regulator of Elovl5, we also reported the sequence of T. ovatus PPARαb (ToPPARαb). The open reading frame (ORF) sequence encoded 469 amino acids possessing four typical characteristic domains, including an N-terminal hypervariable region, a DNA-binding domain (DBD), a flexible hinge domain and a ligand-binding domain (LBD). Thirdly, promoter activity experiments showed that the region from PGL3-basic-Elovl5-5 (-146 bp to +459 bp) was defined as the core promoter by progressive deletion mutation of Elovl5. Moreover, PPARαb overexpression led to a clear time-dependent enhancement of ToElovl5 promoter expression in HEK 293T cells. Fourth, the agonist of PPARαb prominently increased PPARαb and Elovl5 expression, while PPARαb depletion by RNAi or an inhibitor was correlated with a significant reduction of Elovl5 transcription in T. ovatus caudal fin cells (TOCF). In conclusion, the present study provides the first evidence of the positive regulation of Elovl5 transcription by PPARαb and contributes to a better understanding of the transcriptional mechanism of PPARαb in fish.

[Study on female doctors in Xin'an District in the Ming and Qing Dynasties]

The Xin'an female doctors in the Ming and Qing Dynasties could be divided into 4 categories: viz., those who provide general medical services for women patients; those who provide supplementary services for delivery women; those who serve as an assistant of their practicing husband; and those who continued to practice medicine after their husband's death. Although the latter two types could be respected by their families and praised by the society, these female medical practitioners were undervalued and overlooked generally in the society where males were the main body of the medical circle and, moreover, they were not well educated, as well as the influence of Confucianist thoughts of "honorable men and humble women" , hence, their deeds were rarely seen in historical records. However, the emergence of female doctors had certain social causes, and their contributions to local health care should not be ignored.

[Analysis of Xin'an imperial medical officials in the Ming and Qing Dynasties]

Xin'an imperial medical officials of the Ming and Qing Dynasties was a special group of Xin'an doctors. It had exerted a positive and active impact on the development of traditional Chinese medicine. Rooted in the Xin'an region, with higher literacy and noble medical ethics and medical knowhow, through the imperial enlistment, examination, and other ways to enter the palace as imperial medical officials. During their tenure, they wrote books and communicated and merged with the folk medicine actively. After retiring, they were still involved actively in folk medicine activities, thus promoting and influencing the development of local medicine. The formation of Xin'an community of imperial medical officials in the Ming and Qing Dynasties was closely related to the prosperity of regional culture and commerce, and the development of medicine in Xin'an region.

[Clinical research on the treatment for benign lesions in maxillary sinus by endoscopic prelacrimal duct recess approach]

Objective:To explore thecomplication and clinical effects of treatment for benign lesions in maxillary sinusby endoscopic prelacrimal duct recess approach. Method:A retrospective analysis of 82 patients with benign lesions in maxillary sinus.Among them there were 37 cases of inverted papilloma，45 cases of maxillary cyst. According to surgical approaches，they were divided into observation group in which 39 cases were treated by combined middle meatus and prelacrimal duct recess approachunder endoscope,contrast group1in which 22 cases were treated by combined middle meatus and inferior meatus approach and contrast group 2 in which 21 cases were treated bycombined middle meatus and Caldwell-Luc approach. Operation time, amount of bleeding during operation, length of hospitalization, postoperative complications and postoperative curative effect,were observed, recorded and compared among the three groups．Result:The 82 patiengs were successfully treated by surgery and followed up of 3 months to 24 months.There were no significant difference between observation group and contrast group1 in operation time, amount of bleeding during operation,length of hospitalization（P >0.05）, there were statistical difference in post-operative complicationand recurrence rate(P <0.05).There were statistical difference between observation group and contrast group 2 in operation time, amount of bleeding during operation,length of hospitalization andpost-operative complication(P <0.05),there were no significant difference in recurrence rate(P >0.05).Conclusion:Anterior lacrimal recess with the nasal endoscopyis is useful to the lesions of maxillary sinus anterior wall, anterior lower internal wall, anterior lacrimal recess and alveolar crypt. Theoperation time, bleeding and surgical injuries are less. Patients recover fast with less recurrence. Thus, this method is an idealoperation method to deal with benign diseasesin maxillary sinus.

First Report of Leaf Blotch Caused by Pestalotiopsis clavispora on Rosa chinensis in China

Rosa chinensis Jacq, a traditional Chinese ornamental flower, is an important landscaping plant in northern China. Since July 2013, leaf blotch symptoms were observed in the Tianjin flower nursery (117°09' E 39°17' N). The garden exhibited 40% disease incidence with observable symptoms on basal leaves that were yellowed from the edge to the inside area on infected leaves, in the shape of a V. Yellow lesions covered one third to one half of the leaf. Yellow halos were observed at the junction of the healthy and diseased tissues. Small tissue pieces from the edges of lesions were disinfected in 70% ethyl alcohol for 30 s and 1% hypochlorite for 1 min, rinsed thrice in sterile water, plated on potato dextrose agar (PDA), and incubated at 25°C in lighted incubator for 4 days. Fungal colonies that developed on PDA were white and cottony with concentric rings. Black and globular acervuli appeared after 10 days at 25°C. Conidia (n = 20), which were fusiform, were 9.20 to 31.31 (avg. 26.5) × 4.83 to 9.11 (avg. 6.9) μm. Conidia of all isolates were five celled. Apical and basal cells were colorless, while the three median cells were dark brown. The single basal appendage of conidia was 2.85 to 16.05 μm in length and the two to three apical appendages were 5.93 to 36.23 μm in length. According to colony and conidia morphology (number of cells, number of appendages), the isolates were initially identified as Pestalotiopsis spp (2). A 525-bp band was produced in a conventional PCR assay. Primers ITS1 (5'TCCGTAGGTGAACCTGCGC3') and ITS4 (5'TCCTCCGCTTATTGATATGC3') were used to amplify and sequence the internal transcribed spacer region of rDNA. A BLAST search of the NCBI databases showed that isolate YJYK-1 had 99% homology with Pestalotiopsis clavispora isolate hz-067 (Accession No. FJ517545.1). Pathogenicity tests of the novel isolate YJYK-1 were conducted by placing agar plugs (5 mm in diameter) from an actively growing colony on PDA on surface-disinfected (70% ethyl alcohol, 30 s) leaves (1). Control leaves were inoculated with sterile PDA plugs. Plants with inoculated leaves (five per treatment) were placed in lighted growth chambers at 25°C for 10 days and watered as needed. Symptoms on inoculated leaves were similar to those previously described in the nursery. Black acervuli were easily found on the necrotic tissues. Control plants did not show any symptoms. Cultures isolated from the lesions were similar to those isolated previously from leaves in the nursery. Koch's postulates were confirmed after re-isolation. Although the diversity of endophytic Pestalotiopsis species and its distribution was investigated and the host plants were also listed in China (3), to our knowledge, this is the first report of P. clavispora causing leaf blotch on rose R. chinensis in China. References: (1) M. I. Ahmed et al. Eur. J. Plant Pathol. 135:619, 2013. (2) J. Y. Lu. Diagnosis of plant diseases. Page 194 in: Pestalotiopsis. J. Y. Lu et al., eds. China Agriculture Press, Beijing, 1995. (3) J. G. Wei et al. Mycosystema 24:481, 2005.

(18)O(2) label mechanism of sulfur generation and characterization in properties over mesoporous Sm-based sorbents for hot coal gas desulfurization

Using a sol-gel method, SmMeOx/MCM-41 or SBA-15 (Me=Fe, Co and Zn) and corresponding unsupported sorbents were prepared. The desulfurization performance of these sorbents was evaluated over a fixed-bed reactor and the effects of reaction temperature, feed and sorbent composition on desulfurization performance were studied. Samarium-based sorbents used to remove H2S from hot coal gas were reported for the first time. The results of successive sulfidation/regeneration cycles revealed that SmFeO3/SBA-15 sorbent was suitable for desulfurization of hot coal gas in the chemical industry. The formation of elemental sulfur during both sulfidation and regeneration processes depended strongly on the catalytic action of Sm2O2S species, which was confirmed for the first time via high sensitive time of flight mass spectrometer (TOF-MS) using 6%vol(18)O2/Ar regeneration gas and can reduce markedly procedural complexity. The sorbents were characterized using N2-adsorption, high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), temperature-programmed reduction of H2 (H2-TPR), thermogravimetry (TG) and time-of-flight mass spectrometry (TOF-MS) techniques.

Catalytic conversion of acetylene to polycyclic aromatic hydrocarbons over particles of pyroxene and alumina

Polycyclic aromatic hydrocarbons (PAHs) are known to be present in many astrophysical objects and environments, but our understanding of their formation mechanism(s) is far from satisfactory. In this paper, we describe an investigation of the catalytic conversion reaction of acetylene gas to PAHs over pyroxene and alumina. Crystalline silicates such as pyroxenes (with general formula [Mg, Fe]SiO₃) and alumina (Al₂O₃) are observed astrophysically through their infrared spectra and are likely to promote grain surface chemical reactions. In the experiments reported here, gas-phase PAHs were produced by the catalytic reaction of acetylene over crystalline silicates and alumina using a pulsed jet expansion technique and the gaseous products detected using time-of-flight mass spectrometry. In a separate experiment, the catalytic formation of PAHs from acetylene was further confirmed with acetylene gas at atmospheric pressure flowing continuously through a fixed-bed reactor. The gas effluent and carbonaceous compounds deposited on the catalysts were dissolved separately in dichloromethane and analysed using gas chromatography-mass spectrometry. Among the samples studied, alumina showed higher activity than the pyroxene-type grains for the acetylene reaction. It is proposed that formation of the PAHs relies on the Mg²⁺ ions in the pyroxenes and Al³⁺ ions in alumina, where these ions act as Lewis acid sites. X-ray diffraction, Fourier transform infrared and high-resolution transmission electron microscopy techniques were used to characterize the structure and physical properties of the pyroxene and alumina samples.

Formation of (FexMn(2-x))O3 solid solution and high sulfur capacity properties of Mn-based/M41 sorbents for hot coal gas desulfurization

Several MCM-41 materials were synthesized at different conditions by hydrothermal procedure using cheap and easily available industrial water glass as silica source. Fe doped manganese-based oxide/MCM-41 sorbents were prepared by a sol-gel method. The effects of loadings of metal oxide, Fe/Mn molar ratios over MCM-41 and reaction temperature on the performance of sorbent for hot coal gas desulfurization were investigated. Various techniques such as BET, XRD, XPS, LRS and HRTEM were used to characterize the sorbents. The result indicated Fe(3+) ions could occupy a position of Mn(3+) in cubic lattice of Mn2O3 and the (FexMn2-x)O3 solid solution is mainly active phase of sorbent. Moreover, the result of nine successive sulfurization-regeneration cycles of sorbent showed high sulfur adsorption capacity and endurable stability of FeMn4Ox/MCM-41 for H2S removal.

Production of ultra-low-sulfur gasoline: an equilibrium and kinetic analysis on adsorption of sulfur compounds over Ni/MMS sorbents

High performance nickel-based micro-mesoporous silica (Ni/MMS) sorbent was prepared by incipient wetness impregnation with ultrasonic aid (IWI-u) for adsorptive desulfurization (ADS) of commercial gasoline and simulated fuels. The sorbents were characterized with BET, XRD, TPR, SEM, HRTEM and TG/DTG. These results show that 20 wt%Ni/MMS (IWI-u) can still retain the framework of MMS and nickel particles were homogeneously distributed in the MMS channels without any aggregation, which improved significantly the ADS performance of the sorbents. The studies on the ADS kinetics indicate that the adsorption behavior of thiophene (T), benzothiophene (BT) and dibenzothiophene (DBT) over 20 wt%Ni/MMS (IWI-u) can be described appropriately by pseudo second-order kinetic model. The intraparticle diffusion model verified that the steric hindrance and intraparticle diffusion were the rate controlling step of the adsorption process of DBT molecules. Langmuir model can be used to describe the adsorption isotherms for T, BT and DBT due to low coverage. The regeneration sorbent maintains the sulfur removal efficiency of 85.9% for 6 cycles.

Highly stable and regenerable Mn-based/SBA-15 sorbents for desulfurization of hot coal gas

A series of mesoporous xCuyMn/SBA-15 sorbents with different Cu/Mn atomic ratios were prepared by wet impregnation method and their desulfurization performance in hot coal gas was investigated in a fixed-bed quartz reactor in the range of 700-850°C. The successive nine desulfurization-regeneration cycles at 800°C revealed that 1Cu9Mn/SBA-15 presented high performance with durable regeneration ability due to the high dispersion of Mn(2)O(3) particles incorporated with a certain amount of copper oxides. The breakthrough sulfur capacity of 1Cu9Mn/SBA-15 observed 800°C is 13.8 g S/100g sorbents, which is remarkably higher than these of 40 wt%LaFeO(3)/SBA-15 (4.8 g S/100g sorbents) and 50 wt%LaFe(2)O(x)/MCM-41 (5.58 g S/100g sorbents) used only at 500-550°C. This suggested that the loading of Mn(2)O(3) active species with high thermal stability to SBA-15 support significantly increased sulfur capacity at relatively higher sulfidation temperature. The fresh and used xCuyMn/SBA-15 sorbents were characterized by means of BET, XRD, XPS, XAES, TG/DSC and HRTEM techniques, confirmed that the structure of the sorbents remained intact before and after hot coal gas desulfurization.

Interaction of Xestia c-nigrum granulovirus with peritrophic matrix and Spodoptera litura nucleopolyhedrovirus in Spodoptera litura

Xestia c-nigrum granulovirus (XcGV) was tested for its ability to increase Spodoptera litura nucleopolyhedrovirus (SINPV) infection in larvae of S. litura (F.). The interaction of XcGV with peritrophic matrix and SINPV in S. litura also was studied to account for the synergism. In dose-response bioassays with a constant XcGV concentration of 5-mg/ ml capsules and SINPV concentration that varied from 10(3) to 10(7) polyhedral inclusion bodies (PIB) per larva, XcGV increased the virulence of SINPV infection in fifth instars of S. litura. The lethal concentration of 50% individuals (LC50) of SINPV combined with XcGV was 3.35 x 10(5)PIB/ml, which was significantly lower than that of SINPV alone (2.17 x 10(6)). Compared with 10(7) PIB/ml SINPV alone, the lethal time of 50% individuals (LT50) of 10(7) PIB/ml SINPV combined with XcGV was not significantly shortened. In addition, no significant improvement in the activity and killing speed of SINPV progeny was noted after propagation with XcGV, indicating that native characters of SINPV associated with viral potency were not altered by XcGV. Investigation via environmental scanning electronic microscopy showed that the peritrophic matrix (PM) of S. litura exposed to XcGV or XcGV enhancin, or the combination treatment, was markedly disrupted. The outer surface of the PM was loose, or ruptured, which potentially facilitated the passage of virions through the PM. Therefore, it is reasonable to conclude that the synergy between XcGV and SINPV was closely associated with the disruption of the PM in S. litura.

[Molecular tagging of a major powdery mildew resistance gene MlG in wheat derived from wild Emmer by using microsatellite marker]

Powdery mildew caused by Erysiphe graminis f. sp. tritici is one of the most important wheat diseases in many regions of the world. Breeding for resistant cultivars has been proved to be an effective and environmentally safe method to control diseases in wheat production. It is necessary to search for more resistance genes for the diversification of resistance genes in wheat breeding. An Isreali wild emmer wheat (Triticum dicoccoides) accession "G-305-M" was found resistant to the prevailing E. graminis f. sp. tritici isolate Race No. 15 in Beijing region. The powdery mildew resistance has been transferred from G-305-M into common wheat by crossing and backcrossing (G-305-M/781//Jing 411* 3). Genetic analysis showed that the resistance was controlled by a single dominant gene at the seedling stage. A segregating BC2F3 family of the cross "G-305-M/781//Jing 411* 3" with 167 plants was chosen for SSR analysis. Totally 96 wheat microsatellite primer pairs were screened, only one primer pair WMS570 could generate polymorphic DNA fragments between the resistant and susceptible plants. After evaluating this polymorphic marker in the segregating population, the microsatellite locus Xgwm570 mapped on chromosome 6AL was found to be linked to the resistance gene, with the estimated genetic distance of 14.9 +/- 3.0 cM. Based on the origin and chromosomal location of the gene, it is suggested that the resistance gene derived from G-305-M should be a novel Pm gene and is temporarily designated MlG.

[A clinical analysis of pupillary membrane formation after intraocular lens implantation]

In 540 cases having undertaken extracapsular cataract extraction and intraocular lens implantation, a pupillary membrane developed in 76 cases, the rate of occurrence being 14%. Generally, the membrane appears on the fifth post-operative day and corticosteroids are effective in its treatment. After treatment no significant sequela is left and the corrected postoperative visual acuity is not affected. The pathogenesis, treatment and prognosis of the pupillary membrane are briefly discussed in the report.

Crystal structure of an engrailed homeodomain-DNA complex at 2.8 A resolution: a framework for understanding homeodomain-DNA interactions

The crystal structure of a complex containing the engrailed homeodomain and a duplex DNA site has been determined at 2.8 A resolution and refined to a crystallographic R factor of 24.4%. In this complex, two separate regions of the 61 amino acid polypeptide contact a TAAT subsite. An N-terminal arm fits into the minor groove, and the side chains of Arg-3 and Arg-5 make contacts near the 5' end of this "core consensus" binding site. An alpha helix fits into the major groove, and the side chains of IIe-47 and Asn-51 contact base pairs near the 3' end of the TAAT site. This "recognition helix" is part of a structurally conserved helix-turn-helix unit, but these helices are longer than the corresponding helices in the lambda repressor, and the relationship between the helix-turn-helix unit and the DNA is significantly different.