Feeding rhythm of the zoea larvae of Scylla paramamosain: The dynamic feeding rhythm is not completely synchronized with photoperiod.

The feeding rhythm is one of the key factors determining the success of artificial breeding of S. paramamosain. To understand the feeding rhythm of the different zoea larva developmental stages of S. paramamosain, the feeding rate, digestive enzyme activity, and expression of metabolism-related genes were investigated in the present study. The results showed that the S. paramamosain feeding rate has strong diurnal feeding rhythm, being significantly higher at 10:00-14:00 from stages ZI to ZIV. While the feeding rate peaked at 14:00 on Days 10 and 11, the peak shifted to 18:00 on Day 12. The activity of digestive enzymes amylase, pepsin and lipase decreased at night but increased in the daytime, showing a single-phase rhythm similar to that of the feeding rate, suggesting that the digestive enzyme activity was closely associated with the feeding rate during the larval development. Compared to pepsin and lipase, the activity of amylase was the most consistent with feeding rate. In particular, amylase activity peaked at 18:00 on Day 12. Due to its synchronicity with feeding activity, the activity of amylase could provide a potential reference for determining the best feeding time during zoea stages in S. paramamosain breeding. Moreover, the relative mRNA expression of metabolism-related genes SpCHH and SpFAS at most tested points was lower from 10:00 to 14:00, but higher at 18:00 to 6:00 of the next day. On the other hand, the expression patterns of SpHSL and SpTryp were converse to those of SpCHH and SpFAS. Our findings revealed that the S. paramamosain zoea has an obvious feeding rhythm, and the most suitable feeding time was 10:00-18:00 depending on different stages. The feeding rhythm is a critical aspect in aquaculture, influencing a series of physiological functions in aquatic animals. This study provides insights into the feeding rhythm during the zoea development of S. paramamosain, making a significant contribution to optimizing feeding strategy, improving aquafeed utilization, and reducing the impact of residual feed on water environment.

MGMT unmethylation and high levels of CD47 and TIGIT indicate a poor prognosis in adult diffuse gliomas.

Introduction: In 2021, the World Health Organization published a new classification system for central nervous system tumors. This study reclassified the adult diffuse glioma (ADG) into astrocytoma, oligodendroglioma, and glioblastoma (GBM) according to the new tumor classification. Methods: The association of TERT promoter (pTERT) mutation, MGMT methylation, and CD47/TIGIT expression with patient prognosis was investigated. Results: Immunohistochemical analysis showed that the expression levels of CD47 and TIGIT in tumor tissues were significantly higher than those in normal brain tissues. CD47 levels were higher in GBM and grade 4 astrocytoma tissues. TIGIT expression was also higher in patients with GBM. The high expressions of CD47, TIGIT, and CD47/TIGIT were positively correlated with MGMT unmethylation but not pTERT mutation. Moreover, MGMT unmethylation was associated with poor overall survival in astrocytoma. High CD47, TIGIT, and CD47/TIGIT levels were associated with significantly reduced survival in ADG and GBM. GBM, MGMT unmethylation, and high CD47 expression were independent prognostic factors for overall survival in ADG. Discussion: Collectively, these results showed that the MGMT unmethylation and high levels of CD47 and TIGIT are associated with a poor prognosis in ADG. Patients with high CD47 and TIGIT expression may benefit from anti-CD47 and TIGIT immunotherapy.

Temporal and Spatial Signatures of Scylla paramamosain Transcriptome Reveal Mechanistic Insights into Endogenous Ovarian Maturation under Risk of Starvation.

Variability in food availability leads to condition-dependent investments in reproduction. This study is aimed at understanding the metabolic response and regulatory mechanism of female Scylla paramamosain in response to starvation in a temporal- and tissue-specific manner. The mud crabs were starved for 7 (control), 14, 28, and 40 days for histological and biochemical analysis in the hepatopancreas, ovary, and serum, as well as for RNA sequencing on the hepatopancreas and ovary. We further highlighted candidate gene modules highly linked to physiological traits. Collectively, our observations suggested that starvation triggered endogenous ovarian maturation at the expense of hepatopancreas mass, with both metabolic adjustments to optimize energy and fatty acid supply from hepatopancreas to ovary in the early phase, followed by the activation of autophagy-related pathways in both organs over prolonged starvation. These specific adaptive responses might be considered efficient strategies to stimulate ovarian maturation of Scylla paramamosain under fasting stress, which improves the nutritional value of female mud crabs and other economically important crustaceans.

Genomic Characteristics and Functional Analysis of Brucella sp. Strain WY7 Isolated from Antarctic Krill.

Antarctic krill (Euphausia superba) is a key species of the Antarctic ecosystem whose unique ecological status and great development potential have attracted extensive attention. However, the genomic characteristics and potential biological functions of the symbiotic microorganisms of Antarctic krill remain unknown. In this study, we cultured and identified a strain of Brucella sp. WY7 from Antarctic krill using whole-genome sequencing and assembly, functional annotation, and comparative genomics analysis. First, based on 16S rDNA sequence alignment and phylogenetic tree analysis, we identified strain WY7 as Brucella. The assembled genome of strain WY7 revealed that it has two chromosomes and a plasmid, with a total genome length of 4,698,850 bp and an average G + C content of 57.18%. The DNA-DNA hybridization value and average nucleotide identity value of strain WY7 and Brucella anthropi ATCC® 49188TM, a type strain isolated from human clinical specimens, were 94.8% and 99.07%, respectively, indicating that strain WY7 is closely related to Brucella anthropi. Genomic island prediction showed that the strain has 60 genomic islands, which may produce HigB and VapC toxins. AntiSMASH analysis results showed that strain WY7 might produce many secondary metabolites, such as terpenes, siderophores and ectoine. Moreover, the genome contains genes involved in the degradation of aromatic compounds, suggesting that strain WY7 can use aromatic compounds in its metabolism. Our work will help to understand the genomic characteristics and metabolic potential of bacterial strains isolated from Antarctic krill, thereby revealing their roles in Antarctic krill and marine ecosystems.

Molecular characterization and transcriptional response to TiO2-GO nanomaterial exposure of two molt-related genes in the juvenile prawn, Macrobrachium rosenbergii.

In recent years, with the widespread use of TiO2-GO nanocomposite in industry, especially in the remediation of water environments, its toxic effects on aquatic organisms have received increasing attention. As molting is extremely important for crustaceans in their growth, in this study, we cloned the full-length cDNA sequences of two key genes related to molting, nuclear hormone receptor E75 (E75) and nuclear hormone receptor HR3 (HR3), in Macrobrachium rosenbergii, examined the gene expression profile, and investigated their toxicological effects on crustacean molting through nanomaterial exposure. The amino acid sequences for E75 and HR3 were respectively determined to encode 1138 and 363 acid residues. Sequence analysis showed that both E75 and HR3 contain a HOLI domain, with the E75 of M. rosenbergii being more closely related to the E75 of Palaemon carinicauda. These two genes were expressed at the highest levels in muscle, followed by hepatopancreas. The results showed that the expressions of E75 and HR3 in hepatopancreas and muscle tissues were significantly decreased after exposure to 0.1 mg/L of TiO2-GO composite nanoparticles (P < 0.05). This study will serve as a foundation for subsequent research into the evaluation of nanomaterial toxicity on crustacean species.

Insight of vitellogenesis patterns: A comparative analysis of the differences between the primary and secondary vitellogenesis period in the ovary, hepatopancreas, and muscle of mud crab, scylla paramamosain.

The mud crab, Scylla paramamosain, has abundant nutrients in its edible parts, ovary, hepatopancreas, and muscle during the ovarian maturation stage. The ovary of S. paramamosain can re-mature after spawning during the secondary ovarian maturation period. We aimed to analyze the characteristics of the first vitellogenesis period (FVP) and second vitellogenesis period (SVP) of S. paramamosain during ovarian maturation to understand the differences in vitellogenesis patterns between the first and second ovarian maturation periods. Accordingly, the gonadosomatic index (GSI) and hepatopancreatic index (HSI), the external and histological characteristics of the ovary and hepatopancreas, the Sp-Vg (vitellogenin, Vg) expression levels in the hepatopancreas and ovary, and the dynamics of the biochemical components in the ovary, hepatopancreas, and muscle were determined. Based on the results, the GSI was significantly positively correlated with HSI during the FVP and significantly negatively correlated with HSI from stage Ⅳ to stage Ⅴ of the SVP. A significant difference was found between the FVP and SVP in the hepatopancreas. Notably, the hepatopancreas displayed a gradual degeneration trend during the SVP. The expression level of Sp-Vg was significantly higher in the hepatopancreas than that in the ovary during the FVP and SVP. Seventeen amino acids were detected in the hepatopancreas, ovary, and muscle during the FVP and SVP, with glutamate as the predominant amino acid. During the FVP and SVP, the C16:0 and C18:1n9c were the dominant fatty acids in the hepatopancreas and ovary, the MUFA gradually increased in the ovary and hepatopancreas, and a significant difference was found in the dynamic trend of the HUFA and SFA contents from stage Ⅳ to stage Ⅴ between the FVP and SVP. These findings indicate that the ovary can re-mature after spawning in S. paramamosain and can maintain the status of the first ovarian maturation; however, the hepatopancreas gradually degenerate during the SVP.

Identification and Evolution Analysis of the Complete Methyl Farnesoate Biosynthesis and Related Pathway Genes in the Mud Crab, Scylla paramamosain.

The sesquiterpenoid hormone methyl farnesoate (MF) plays a vital role during crustacean development, which is mainly evidenced by its varied titers during different developmental stages. However, the biosynthesis pathways of MF remain obscure to some extent. In this study, we identified the complete MF biosynthesis and related pathway genes in Scylla paramamosain, including three involved in acetyl-CoA metabolism, eight in the mevalonate pathway, five in the sesquiterpenoids synthesis pathway, and five in the methionine cycle pathway. Bioinformatics, genomic structure, and phylogenetic analysis indicated that the JH biosynthesis genes might have experienced evolution after species differentiation. The mRNA tissue distribution analysis revealed that almost all genes involving in or relating to MF syntheses were highly expressed in the mandibular organ (MO), among which juvenile hormone acid methyltransferase was exclusively expressed in the MO, suggesting that most of these genes might mainly function in MF biosynthesis and that the methionine cycle pathway genes might play a crucial regulatory role during MF synthesis. In addition, the phylogenetic and tissue distribution analysis of the cytochrome P450 CYP15-like gene suggested that the epoxidized JHs might exist in crustaceans, but are mainly synthesized in hepatopancreas rather than the MO. Finally, we also found that betaine-homocysteine S-methyltransferase genes were lost in insects while methionine synthase was probably lost in most insects except Folsomia candida, indicating a regulatory discrepancy in the methionine cycle between crustaceans and insects. This study might increase our understanding of synthetic metabolism tailored for sesquiterpenoid hormones in S. paramamosain and other closely related species.

Comparative Metabolomics and Lipidomics of Four Juvenoids Application to Scylla paramamosain Hepatopancreas: Implications of Lipid Metabolism During Ovarian Maturation.

This study was the first to evaluate multiple hormonal manipulations to hepatopancreas over the ovarian development stages of the mud crab, Scylla paramamosain. A total of 1258 metabolites in 75 hepatopancreas explants from five female crabs were induced by juvenile hormone III (JH III), methyl farnesoate (MF), farnesoic acid (FA) and methoprene (Met), as identified from combined metabolomics and lipidomics (LC-MS/MS). 101 significant metabolites and 47 significant pathways were selected and compared for their comprehensive effects to ovarian maturation. While MF played an extensive role in lipid accumulation, JH III and Met shared similar effects, especially in the commonly and significantly elevated triglycerides and lysophospholipids (fold change≥2 and ≤0.5, VIP≥1). The significant upregulation of ß-oxidation and key regulators in lipid degradation by FA (P ≤ 0.05) resulted in less lipid accumulation from this treatment, with a shift toward lipid export and energy consumption, unlike the effects of MF, JH III and Met. It was possible that MF and FA played their own unique roles and acted in synergy to modulate lipid metabolism during crab ovarian maturation. Our study yielded insights into the MF-related lipid metabolism in crustacean hepatopancreas for the overall regulation of ovarian maturation, and harbored the potential use of juvenoids to induce reproductive maturity of this economic crab species.

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To investigate the ion regulation of large yellow croaker (Larimichthys crocea) under hypoxia and acidification stresses, we investigated the effects of hypoxia (dissolved oxygen DO 3.5 mg·L-1, pH 8.1), acidification (DO 7.0 mg·L-1, pH 7.35) and combined stresses of hypoxia and acidification (DO 3.5 mg·L-1, pH 7.35) on gill tissue structure and physiological indices related to ion regulation of juvenile L. croaker. The results showed that, under hypoxia stress, gill Na+/K+-ATPase activity, serum Na+, Ca2+ and Cl- contents of juvenile L. croaker decreased first and then increased. Under acidification stress, gill Ca2+-ATPase activity, serum Na+ and Ca2+ contents of juvenile L. croaker increased first and then decreased. Under the combined stresses of hypoxia and acidification, Na+/K+-ATPase activity and Na+, K+ and Ca2+ contents increased first and then decreased, while Ca2+-ATPase activity and Cl- content decreased first and then increased. The results of gill histology showed that hypoxia and acidification stresses led to the detachment of gill epithelial cells, and the combined stresses of hypoxia and acidification led to proliferation, hypertrophy and swelling of gill epithelial cells. Comprehensive analysis showed that hypoxia and acidification stress affected the activities of major ion regulatory enzymes in juvenile L. croaker and caused different degrees of damage to gill tissue, resulting in imbalanced ion regulation in juvenile L. croaker.

Environmental risk characteristics of bacterial antibiotic resistome in Antarctic krill.

Antibiotic resistance genes (ARGs) are ubiquitous in nature, especially in the current era of antibiotic abuse, and their existence is a global concern. In the present study, we discovered that Antarctic krill-related culturable bacteria are resistant to ß-lactam, tetracyclines, aminoglycosides, and sulphamethoxazole/trimethoprim based on the antibiotic efflux mechanism. In addition, the co-occurrence of ARGs with insertion sequence (IS) (tnpA, IS91) and Intl1 on the isolates and the phylogenetic analysis results of the whole-genome revealed low-frequency ARG transfer events, implying the transferability of these ARGs. These findings provide an early warning for the wide assessment of Antarctic microbiota in the spread of ARGs. Our work provides novel insights into understanding ARGs in culturable host-associated microorganisms, and their ecological risks and has important implications for future risk assessments of antibiotic resistance in extreme environments.

The Role of Flagellin B in Vibrio anguillarum-Induced Intestinal Immunity and Functional Domain Identification.

Vibrio anguillarum, an opportunistic pathogen of aquatic animals, moves using a filament comprised of polymerised flagellin proteins. Flagellins are essential virulence factors for V. anguillarum infection. Herein, we investigated the effects of flagellins (flaA, flaB, flaC, flaD and flaE) on cell apoptosis, TLR5 expression, and production of IL-8 and TNF-α. FlaB exhibited the strongest immunostimulation effects. To explore the functions of flaB in infection, we constructed a flaB deletion mutant using a two-step recombination method, and in vitro experiments showed a significant decrease in the expression of TLR5 and inflammatory cytokines compared with wild-type cells. However in the in vivo study, expression of inflammatory cytokines and intestinal mucosal structure showed no significant differences between groups. Additionally, flaB induced a significant increase in TLR5 expression based on microscopy analysis of fluorescently labelled TLR5, indicating interactions between the two proteins, which was confirmed by native PAGE and yeast two-hybrid assay. Molecular simulation of interactions between flaB and TLR5 was performed to identify the residues involved in binding, revealing two binding sites. Then, based on molecular dynamics simulations, we carried out thirteen site-directed mutations occurring at the amino acid sites of Q57, N83, N87, R91, D94, E122, D152, N312, R313, N320, L97, H316, I324 in binding regions of flaB protein by TLR5, respectively. Surface plasmon resonance (SPR) was employed to compare the affinities of flaB mutants for TLR5, and D152, D94, I324, N87, R313, N320 and H316 were found to mediate interactions between flaB and TLR5. Our comprehensive and systematic analysis of V. anguillarum flagellins establishes the groundwork for future design of flagellin-based vaccines.

SpSR-B2 functions as a potential pattern recognition receptor involved in antiviral and antibacterial immune responses of mud crab Scylla paramamosain.

Although class B scavenger receptors (SR-Bs) in mammals are multifunctional molecules, the functions of SR-Bs in invertebrates remain largely unknown. In this study, we characterized an SR-B homolog, namely SpSR-B2, from Scylla paramamosain. SpSR-B2 shared high similarity with mammalian SR-Bs, and exhibited specific binding activity to ac-LDL, indicating that it may be a new member of SR-B class in invertebrates. SpSR-B2 was upregulated after challenge with white spot syndrome virus (WSSV) or bacteria. Binding assays showed that SpSR-B2 specifically interacted with WSSV envelope protein VP24. Besides, SpSR-B2 could bind to all tested bacterial cells and agglutinate these bacteria. SpSR-B2 also exhibited a strong binding activity to LPS but weak binding activities to other tested polysaccharides. These findings indicated that SpSR-B2 was a potential recognition molecule for viral protein VP24 and bacterial LPS. Knockdown of SpSR-B2 resulted in dramatically decreased expressions of certain antimicrobial peptides (AMPs), and overexpression of SpSR-B2 led to the increased expression of the AMP of SpALF2, suggesting that SpSR-B2 could regulate the expression of AMPs. Taken together, this study revealed that SpSR-B2 functioned as a potential pattern recognition receptor participating in antiviral and antibacterial immunity, and provided new insights into the immune functions of invertebrate SR-Bs.

Associations between TG/HDL ratio and insulin resistance in the US population: a cross-sectional study.

BACKGROUND: Clinical data on the relationship between triglycerides (TG)/HDL ratio and insulin resistance (IR) suggest that TG/HDL ratio may be a risk factor for IR. However, there is evidence that different races have different risk of developing IR. The relationship on TG/HDL ratio and IR in various populations needs to be improved. Therefore, we investigated whether TG/HDL ratio was linked to IR in different groups in the United States after controlling for other covariates. METHODS: The current research was conducted in a cross-sectional manner. From 2009 to 2018, the National Health and Nutrition Examination Survey (NHANES) had a total of 49,696 participants, all of whom were Americans. The target-independent variable was TG/HDL ratio measured at baseline, and the dependent variable was IR. Additionally, the BMI, waist circumference, education, race, smoking, alcohol use, alanine transaminase, aspartate transaminase, and other covariates were also included in this analysis. RESULTS: The average age of the 10,132 participants was 48.6 ± 18.4 years, and approximately 4936 (48.7%) were males. After correcting for confounders, fully adjusted logistic regression revealed that TG/HDL ratio was correlated with IR (odds ratio = 1.51, 95% CI 1.42-1.59). A nonlinear interaction between TG/HDL ratio and IR was discovered, with a point of 1.06. The impact sizes and CIs on the left and right sides of the inflection point were 6.28 (4.66-8.45) and 1.69 (1.45-1.97), respectively. According to subgroup analysis, the correlation was strong in females, alcohol users, and diabetes patients. Meanwhile, the inverse pattern was observed in the aged, obese, high-income, and smoking populations. CONCLUSION: In the American population, the TG/HDL ratio is positively associated with IR in a nonlinear interaction pattern.

Whole genome sequencing and comparative genomic analyses of Planococcus alpniumensis MSAK28401T, a new species isolated from Antarctic krill.

BACKGROUND: Extremophiles have attracted much attention in the last few decades, as they possess different properties by producing certain useful metabolites. However, the secondary metabolism of the extremophiles of Antarctic krill has received little attention. RESULTS: In this study, a new bacterial strain MSAK28401T from Antarctic krill was isolated and identified. The results of analysis on phenotypic, chemotaxonomic, and genomic characteristics showed that the strain MSAK28401T belongs to the genus Planococcus. Cells of this strain were coccoid (0.89-1.05 µm) and aerobic. The majority of the fatty acid content was C15:0 anteiso (37.67 ± 0.90%) followed by C16:1 ω7c alcohol (10.37 ± 1.22%) and C16:0 iso (9.36 ± 0.71%). The calculated average nucleotide identity and DNA-DNA hybridization values between the strain MSAK28401T and type strains P. citreus DSM 20549T and P. rifietoensis M8T were lower than 91 and 70%, respectively. The strain MSAK28401T (=KCTC 43283T and MCCC 1k05448T) represented a new member of the genus Planococcus and was named P. alpniumensis sp. nov. Moreover, genes involved in the degradation of aromatic compounds (e.g., salicylate, gentisate, and quinate) were found in the genome, implying that strain MSAK28401T has an aromatic compound as its potential metabolite. This work will help us understand the genomic characteristics and potential metabolic pathway of Planococcus from Antarctic krill. CONCLUSIONS: This study reported the genomic information and phenotypic characteristics of the new strain P. alpniumensis MSAK28401T isolated from Antarctic krill, and provided the genome information of Planococcus strains for further studying the function roles in aromatic compound metabolism.

Genetic diversity and population structure analysis of Lateolabrax maculatus from Chinese coastal waters using polymorphic microsatellite markers.

In order to provide valuable guidelines for the conservation of germplasm of Lateolabrax maculatus, the genetic diversity and population structure analysis were evaluated for eight geographic populations along coastal regions of China, using 11 microsatellite DNA markers. The genetic parameters obtained showed that, eight populations can be clustered into two groups, the Northern group and the Southern group, concordant with their geographical positions. The UPGMA tree constructed according to the Nei's genetic distance along with the structure analysis and discriminant analysis of principal component also supported this result. This might be explained by the geographic separation and the divergent environmental conditions among the populations. It's worth noting that, QD (Qingdao) population from northern area was assigned to the Southern group and showed a close genetic relationship and similar genetic constitution with the southern populations. We speculated that large scales of anthropogenic transportation of wild fries from QD populations to the southern aquaculture areas in history should be the primary cause. The populations from GY (Ganyu), RD (Rudong) and BH (Binhai) had higher genetic diversity and showed limited genetic exchange with other populations, indicating better conservation of the natural resources in these regions. All populations were indicated to have experienced bottleneck events in history.

Alternations in the liver metabolome, skin and serum antioxidant function of silver pomfret (Pampus Argenteus) is induced by jellyfish feeding.

Many fish species are known to feed on jellyfish. Herein, we observed the effects of jellyfish feeding on silver pomfret using gas chromatography tandem time-of-flight mass spectrometry (GC-TOF-MS) based on metabolomics. We studied the effects of feeding on jellyfish on skin and serum immune of silver pomfret. Healthy silver pomfret (initial weight, 13.40 ± 1.565 g) was divided into two groups: control and feeding. The pomfrets were fed jellyfish at 2, 6, 12, 24, and 72 h, and samples were obtained. Statistical analysis revealed that after jellyfish feeding, most serum immune indicators did not show a significant change; however, skin immune indicators indicated that silver pomfret elicit a stress response on encountering jellyfish, gradually adapting to their presence. We therefore conducted further experiments involving two groups: group A, which was not fed any extra jellyfish, and group B, which was fed extra jellyfish (approximately 10% weight of silver pomfret) every day for 60 days. Orthogonal partial least squares discriminant analysis led to the identification of stronger biomarkers, with the liver metabolome showing obvious variations between the groups (group B vs. A). After feeding jellyfish by silver pomfret, some amino acids, amines, and unsaturated fatty acids in the liver tissue showed a significant increase. Our results, thus, not only reveal changes in physiological indices of silver pomfret after feeding on jellyfish but also provide a new idea for further optimizing the feed formula for silver pomfret culture.

A chromosome-level genome of the mud crab (Scylla paramamosain estampador) provides insights into the evolution of chemical and light perception in this crustacean.

Mud crabs, found throughout the Indo-Pacific region, are coastal species that are important fisheries resources in many tropical and subtropical Asian countries. Here, we present a chromosome-level genome assembly of a mud crab (Scylla paramamosain). The genome is 1.55 Gb (contig N50 191 kb) in length and encodes 17,821 proteins. The heterozygosity of the assembled genome was estimated to be 0.47%. Effective population size analysis suggested that an initial large population size of this species was maintained until 200 thousand years ago. The contraction of cuticle protein and opsin genes compared with Litopenaeus vannamei is assumed to be correlated with shell hardness and light perception ability, respectively. Furthermore, the analysis of three chemoreceptor gene families, the odorant receptor (OR), gustatory receptor (GR) and ionotropic receptor (IR) families, suggested that the mud crab has no OR genes and shows a contraction of GR genes and expansion of IR genes. The numbers of the three gene families were similar to those in three other decapods but different from those in two nondecapods and insects. In addition, IRs were more diversified in decapods than in nondecapod crustaceans, and most of the expanded IRs in the mud crab genome were clustered with the antennal IR clades. These findings suggested that IRs might exhibit more diverse functions in decapods than in nondecapods, which may compensate for the smaller number of GR genes. Decoding the S. paramamosain genome not only provides insight into the genetic changes underpinning ecological traits but also provides valuable information for improving the breeding and aquaculture of this species.

Population genetic diversity of mud crab (Scylla paramamosain) from southeast coastal regions of China based on mitochondrial COI gene sequence.

Mud crab (Scylla paramamosain) is a native and economically important species in East Asia. In order to provide a comprehensive genetic background for the resource protection and management in this species, the genetic diversity and population structure of S. paramamosain were analyzed based on mitochondrial cytochrome oxidase subunit I (COI) gene sequence. Totally, 599 individuals were sampled from 20 populations, including 18 wild and two cultured populations from five provinces along southeastern coast of China. After the sequencing of a 638 bp fragment of COI gene, 84 variable sites were found and no insertion or deletion was detected. The H2 (haplotype 2) was the dominant hapolotye shared by 301 individuals (50.3% of all individuals) and existed in all localities. In addition, a high percent of unique haplotypes (53 of 93 haplotyoes) was found. The average nucleotide diversity (π) of all populations was 0.00194, ranging from 0.00010 (NHF1) to 0.00305 (SHCM). The haplotype diversity (h) ranged from 0.067 (NHF1) to 0.876 (CM) with an average 0.738. All of the populations showed high h (>0.5) except NHF1. Genetic distance ranged from 0.00063 to 0.00337 between populations and from 0.00010 to 0.00374 within populations. The molecular variance analysis (AMOVA) showed that the total genetic variation mainly occurred within populations (99.68%) and only 0.32% was contributed by among populations variation. No significant genetic differentiation was observed among all wild populations except that between BA and SHCM (Fst = 0.0.05707, P < 0.05), indicating a low level of genetic differentiation among localities. It is worth to note that two progeny population (HNF1 and NHF1) showed significantly different genetic variation, which suggested that a large quantity of parents could help to improve the genetic diversity of progeny populations.

Molecular characterization of TLR3 and TRIL in silvery pomfret (Pampus argenteus) and their expression profiles in response to bacterial components.

Toll-like receptors (TLRs) play important roles in the innate system by recognizing pathogen-associated molecular patterns derived from various microbes. In this study, we reported the cloning and identification of paTLR3 and paTLR4 interactor with leucine rich repeats (TRIL) cDNA from silvery pomfret (Pampus argenteus). The full-length paTLR3 and paTRIL cDNA were 2996 and 3163 bp long, respectively. Both of the two proteins contained many LRR domains, one LRR-C terminal domain and one transmembrane region, which fits with the characteristic TLR and its analogue domain architecture. Phylogenetic analyses revealed that paTLR3 and paTRIL shared the closest relationship with Lateolabrax japonicas and Notothenia coriiceps, respectively. The expression levels of paTLR3 and paTRIL varied greatly among the examined tissues with the highest expression both in liver. Following exposure to V. anguillarum flagellin, A. hydrophila lipopolysaccharide (LPS) and L. plantarum lipoteichoic acid (LTA), paTLR3 and paTRIL were all up-regulated. V. anguillarum flagellin induced the highest expression levels of paTLR3 and paTRIL. A. hydrophila flagellin and A. hydrophila LPS induced the highest expression levels of IL-1ß and IL-8, respectively. The present results will provide the valuable information for understanding the structure, function and the immune defense process of paTLR3 and paTRIL in silvery pomfret.