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.

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.

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.

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.

Tissue-based transcriptomics of Chionodraco hamatus: Sequencing, de novo assembly, annotation and marker discovery.

Here, we explored the liver, heart and muscle tissue transcriptome of the haemoglobinless Antarctic fish Chionodraco hamatus using the Illumina paired-end RNA sequencing. A total of 114,028 unigenes with a mean length of 794.24 bp was produced. Annotation of these unigenes showed that 29.16% and 35.52% of them had hits in the nucleotide (Nt) and protein (Nr) databases, respectively. In addition, 29.10% and 35.28% unigenes were annotated in the SwissProt and TrEMBL databases while 23.27% and 21.08% of unigenes were annotated in the conserved domain (CCD) and protein family (PFAM) databases, respectively. The results of eukaryotic orthologous groups (KOG) classification analysis showed that around 21.36% of unigenes could be mapped. Differential gene expression analysis indicated that 16,331, 16,291 and 13,262 differentially expressed genes (DEG) could be screened between muscle and heart, muscle and liver and heart and liver, respectively. A significant enrichment analysis of these DEGs revealed their implication in important biological processes, molecular functions, cellular components and diverse pathways. Furthermore, a total of 24,455 simple sequence repeats (SSR) were detected from the generated tissue transcriptome. The transcriptome data produced in this study will constitute an important resource for improving our knowledge of C. hamatus functional genomics and will facilitate future studies regarding this species.

RNA-sequencing of the sturgeon Acipenser baeri provides insights into expression dynamics of morphogenic differentiation and developmental regulatory genes in early versus late developmental stages.

BACKGROUND: Acipenser baeri, one of the critically endangered animals on the verge of extinction, is a key species for evolutionary, developmental, physiology and conservation studies and a standout amongst the most important food products worldwide. Though the transcriptome of the early development of A. baeri has been published recently, the transcriptome changes occurring in the transition from embryonic to late stages are still unknown. The aim of this work was to analyze the transcriptomes of embryonic and post-embryonic stages of A. baeri and identify differentially expressed genes (DEGs) and their expression patterns using mRNA collected from specimens at big yolk plug, wide neural plate and 64 day old sturgeon developmental stages for RNA-Seq. RESULTS: The paired-end sequencing of the transcriptome of samples of A. baeri collected at two early (big yolk plug (T1, 32 h after fertilization) and wide neural plate formation (T2, 45 h after fertilization)) and one late (T22, 64 day old sturgeon) developmental stages using Illumina Hiseq2000 platform generated 64039846, 64635214 and 75293762 clean paired-end reads for T1, T2 and T22, respectively. After quality control, the sequencing reads were de novo assembled to generate a set of 149,265 unigenes with N50 value of 1277 bp. Functional annotation indicated that a substantial number of these unigenes had significant similarity with proteins in public databases. Differential expression profiling allowed the identification of 2789, 12,819 and 10,824 DEGs from the respective T1 vs. T2, T1 vs. T22 and T2 vs. T22 comparisons. High correlation of DEGs' features was recorded among early stages while significant divergences were observed when comparing the late stage with early stages. GO and KEGG enrichment analyses revealed the biological processes, cellular component, molecular functions and metabolic pathways associated with identified DEGs. The qRT-PCR performed for candidate genes in specimens confirmed the validity of the RNA-seq data. CONCLUSIONS: This study presents, for the first time, an extensive overview of RNA-Seq based characterization of the early and post-embryonic developmental transcriptomes of A. baeri and provided 149,265 gene sequences that will be potentially valuable for future molecular and genetic studies in A. baeri.

Two transcripts of HMG-CoA reductase related with developmental regulation from Scylla paramamosain: Evidences from cDNA cloning and expression analysis.

3-Hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductases (HMGRs), which catalyze the conversion of HMG-CoA to mevalonate, may have an important role in the synthesis of methyl farnesoate (MF). In this study, we obtained two HMGR cDNA sequences termed Sp-HMGR1 (membrane-bound form) and Sp-HMGR2 (soluble form), which encode 967 and 654 amino acids, respectively. The two cDNAs possess entirely identical sequences except that Sp-HMGR1 is 1,382 bp, which encodes a sterol-sensed domain (SSD; a membrane-bound domain) and was first found in crustacean HMGR, larger than Sp-HMGR2. Thus, it was deduced that these cDNAs might be derived from a single genomic DNA sequence. Sp-HMGRs have the typical features of the HMGR class of proteins. However, residue 844 in Sp-HMGR1, which is usually occupied by a Ser residue in other species, has an unusual Ala substitution. This Ser is thought to be involved in enzyme activity regulation by reversible phosphorylation. A putative "PEST" sequence that, until now, has only been found in crustacean species was also identified in the C-terminus of both transcripts, and a sterol-sensing domain, which was first found in crustacean species, was identified in Sp-HMGR1; these findings suggest that Sp-HMGR might function in some special regulatory mechanism. Furthermore, the quantitative real-time polymerase chain reaction results showed that the two transcripts have different expression patterns; Sp-HMGR2 was mainly expressed in the mandibular organ (MO) of adult crabs, whereas Sp-HMGR1 was mainly expressed in other tissues and fertilized eggs up until the fourth juvenile crab stage. The fluctuating gene expression seemed to suggest a relationship between Sp-HMGRs and the development of the crab, especially during the larval stage. Besides, the fluctuation of Sp-HMGR1 in ovary, brain, and thoracic ganglia during the ovary development seemed to have some correlation with the nutrition accumulation of ovaries, whether the SSD domain evolved in this process deserve further investigation. Moreover, it remains unclear whether the significant variation in ovary, brain, and thoracic ganglia during ovary development suggests that other tissues in addition to the MO could synthesize MF.

Characterization of 40 single nucleotide polymorphism (SNP) via Tm-shift assay in the mud crab (Scylla paramamosain).

In this study, single nucleotide polymorphism (SNP) were identified, confirmed and genotyped in the mud crab (Scylla paramamosain) using Tm-shift assay. High quality sequences (13, 311 bp long) were obtained by re-sequencing that contained 91 SNPs, with a density of one SNP every 146 bp. Of all 91 SNPs, 40 were successfully genotyped and characterized using 30 wild specimens by Tm-shift assay. The minor allele frequency per locus ranged from 0.017 to 0.500. The observed and expected heterozygosity, and polymorphism information content (PIC) ranged from 0.000 to 0.600, from 0.033 to 0.509, and from 0.033 to 0.375, respectively, with an average of 0.142, 0.239 and 0.198 per locus. Seventeen SNPs were significantly deviated from Hardy-Weinberg equilibrium. No significant linkage disequilibrium between pairs of loci was detected after sequential Bonferroni correction (P > 0.00125). Seventeen SNPs were related with known function genes. This study provided new molecular markers for investigation of population genetic diversity, construction of genetic linkage maps and molecular marker-assisted selection in this important crustacean species.

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.

Multiplex immune-related genes expression analysis response to bacterial challenge in mud crab, Scylla paramamosain.

Crabs lack an acquired adaptive immune system and host defense is believed to depend entirely on innate, non-adaptive mechanisms to resist invasion by pathogens. Discovery of immune-related factors are helpful for understanding the molecular response of crabs to pathogens. The mud crab Scylla paramamosain is an important marine species for aquaculture in China because of its high nutritional value for humans. In recent years, the crab is prone to being infected by microbes with the enlargement of breeding scale. In this study, eight immune-related genes were analyzed by multiplex genes expression analysis using the GenomeLab GeXP analysis system (Beckman Coulter). The expression levels of all the detected genes rose after challenged by the live bacteria, but the levels of only four genes (C-type lectin, alpha 2-macroglobulin, HSP70 and thioredoxin 1) increased after challenge in heat-killed bacteria group. So the live bacteria were more effective in motivating expressions of immune factors than heat-killed bacteria. However, the transcript of C-type lectin firstly increased at 1 h after challenge in both heat-killed and live bacteria group. This indicated that C-type lectin was a quite susceptive immune factor responding to external pathogen. In group challenged by live bacteria, the genes of alpha 2-macroglobulin, HSP40, thioredoxin 1 and prophenoloxidase activating factor (PPAF) showed response earlier than the other genes. The rise of PPAF expression preceded prophenoloxidase (proPO), which suggested that PPAF might trigger production of proPO transcripts in the early stage of phenoloxidase reaction system. C-type lectin, proPO, thioredoxin 1, HSP40, and alpha 2-macroglobulin are very important immunity factors in response to bacterial infection. According to the result of heat-killed group, HSP70 is a sensitively inductive factor to foreign stimulus compared with the other genes. The multi-gene analysis presented an alternative approach for screening of immune-related genes, and provided a more global overview of genes transcript alteration in response to bacterial challenge.

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.

High genetic diversity and low differentiation in mud crab (Scylla paramamosain) along the southeastern coast of China revealed by microsatellite markers.

The mud crab (Scylla paramamosain) is a carnivorous portunid crab, mainly distributed along the southeastern coast of China. Mitochondrial DNA analysis in a previous study indicated a high level of genetic diversity and a low level of genetic differentiation. In this study, population genetic diversity and differentiation of S. paramamosain were investigated using nine microsatellite markers. In total, 397 wild specimens from 11 locations on the southeastern coast of China were sampled and genotyped. A high level of genetic diversity was observed, with the number of alleles, and the observed and expected heterozygosity per location in the range 7.8-9.6, 0.62-0.77 and 0.66-0.76, respectively. AMOVA analysis indicated a low level of genetic differentiation among the 11 locations, despite the fact that a statistically significant fixation index (F(ST)) value was found (F(ST)=0.0183, P<0.05). Out of 55 pairwise location comparisons, 39 showed significant F(ST) values (P<0.05), but all of them were lower than 0.05, except for one between Sanmen and Shantou locations. No significant deficiency of heterozygotes (inbreeding coefficient F(IS)=0.0007, P>0.05) was detected for all locations except Sanmen and Zhanjiang. Cluster analysis using UPGMA showed that all locations fell into one group except Sanmen. Significant association was found between genetic differentiation in terms of F(ST)/(1-F(ST)) and the natural logarithm of geographical distance (r(2)=0.1139, P=0.02), indicating that the genetic variation pattern closely resembled an isolation by distance model. This study supports the proposal of high genetic diversity and low genetic differentiation in S. paramamosain along the southeastern coast of China.

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.

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.

Development of eighteen polymorphic microsatellite markers in Scylla paramamosain by 5' anchored PCR technique.

The mud crab Scylla paramamosain plays a significant role in fishery resources in China. In this study, we developed 18 polymorphic microsatellite markers in this important crab by 5' anchored PCR technique. A total of 125 alleles were detected in a single population of 32 individuals of S. paramamosain. The number of alleles per locus ranged from five to nine, with the allele size ranging from 166 to 316 bp. The polymorphism information content (PIC), observed and expected heterozygosity ranged from 0.39 to 0.88, from 0.33 to 0.92 and from 0.42 to 0.86, respectively. Three loci (Scypa13, Scypa14 and Scypa15) deviated significantly from Hardy-Weinberg equilibrium (HWE) after Bonferroni correction (P < 0.0028), and no linkage disequilibrium was found between loci pairs. These polymorphic microsatellite markers will be useful for the study of population genetic structure, construction of genetic linkage maps and mapping of economically quantitative trait loci (QTL) in S. paramamosain.

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.

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.