Internet addiction and health-related quality of life in adolescents: The mediating role of sleep disturbance.

BACKGROUND: Internet addiction (IA) has emerged as a recognized risk factor associated with impaired health-related quality of life (HRQOL) in adolescents. However, the role of sleep disturbance in this association remains unclear. This study aimed to investigate the association of IA with HRQOL in Chinese adolescents and to evaluate the potential mediating role of sleep disturbance. METHODS: A cross-sectional study was conducted among adolescents attending six randomly selected middle schools in Guangzhou, China. Adolescents self-reported their internet use using the Young Diagnostic Questionnaire. HRQOL and sleep disturbance were assessed by the Pediatric Quality of Life Inventory version 4.0 and the Pittsburgh Sleep Quality Index, respectively. Multivariate linear regression analysis was employed to assess the association between IA and HRQOL. Baron and Kenny's causal steps method was used to examine the possible mediating role of sleep disturbance. RESULTS: Of the 6473 adolescents included, 23.5% had maladaptive internet use (MIU) and 16.6% had pathological internet use (PIU). Compared to adolescents with adaptive internet use (AIU), those with IA had significantly lower scores across all HRQOL dimensions and summary scales. Mediation analysis revealed that sleep disturbance was a significant mediator. Specifically, sleep disturbance mediated 34.55% of the effects of MIU and 34.06% of the effects of PIU on the HRQOL total scale score , respectively. CONCLUSIONS: IA was associated with poorer HRQOL, indicating the needs of preventing IA in Chinese adolescents. Additionally, our findings underscored the importance of enhancing sleep quality to mitigate the adverse impact of IA on adolescents' well-being.

Association between healthy lifestyle factors and health-related quality of life among Chinese adolescents: the moderating role of gender.

BACKGROUND: To examine the associations of the independent and combined healthy lifestyle factors with health-related quality of life (HRQOL) in adolescents, and to test the moderating role of gender. METHODS: This cross-sectional study included 5125 adolescents aged between 11 and 20 years. They provided self-reported data on six healthy lifestyle factors, including never smoking, never drinking, good sleep quality, sufficient sleep duration, appropriate Internet use, and adequate physical activity. Adolescents' HRQOL was evaluated using the Pediatric Quality of Life Inventory version 4.0. Linear regression models were conducted to explore the association of individual and combined healthy lifestyle factors with adolescents' HRQOL. We further performed stratified analyses and likelihood ratio test to explore the moderating role of gender in these associations. RESULTS: Of the included adolescents, the proportions with 0-2, 3, 4, and 5-6 healthy lifestyle factors were 13.6%, 26.4%, 44.3%, and 15.7%, respectively. Compared to adolescents with composite healthy lifestyle scores of 0-2, those with scores of 3, 4, or 5-6 had significantly higher HRQOL scores across all dimensions, summary scales, and total scale in both unadjusted and adjusted models. Specifically, adolescents with 5-6 healthy lifestyle factors had a total scale score that was 19.03 (95%CI: 17.76 to 20.30) points higher than their counterparts who only had 0-2 healthy lifestyle factors. Significant dose-response patterns were also observed in aforementioned associations. Gender was a significant moderator in the associations between composite healthy lifestyle groups and HRQOL scores, except for the social functioning dimension. CONCLUSIONS: Our results confirmed that combined healthy lifestyle factors were associated with improved HRQOL among adolescents, with a stronger association observed in girls. These findings underscore the necessity for education and healthcare authorities to design health-promoting strategies that encourage multiple healthy lifestyle factors in adolescents, with the objective of enhancing their overall health outcomes.

IL-1ß-mediated inflammatory responses in intervertebral disc degeneration: Mechanisms, signaling pathways, and therapeutic potential.

Intervertebral disc degeneration (IDD) has been widely recognized as the primary cause of low back pain and is one of the major chronic diseases imposing a severe socioeconomic burden worldwide. IDD is a degenerative process characterized by inflammatory responses, and its underlying pathological mechanisms remain complex. Genetic, developmental, biochemical, and biomechanical factors contribute to the development of IDD. There is a pressing need for an effective non-surgical treatment, mainly due to the lack of comprehensive understanding of the specific mechanisms involved and the effective therapeutic targets for IDD. Recently, interleukin (IL)-1ß has been recognized as an essential inflammatory factor and a key mediator of the inflammatory process in IDD. Current studies have found that IL-1ß is mainly involved in IDD by affecting the metabolism of the extracellular matrix and regulating cell death (RCD), such as apoptosis, pyroptosis, and ferroptosis (a new form of RCD). Although analysis of clinical samples from different laboratories confirmed how IL-1ß is induced in IDD, its specific signal transduction pathway, and the inflammatory role mediated in IDD remains unclear. This review describes the molecules and mechanisms involved in IL-1ß-mediated inflammatory responses, and their roles in resolving the inflammatory process in IDD. Understanding the signaling pathways involved in IL-1ß may lead to a new class of targets that promote remission for IDD patients. This review aims to provide a framework for the treatment of IDD by analyzing the signaling mechanism and function related to IL-1ß, especially in terms of inflammation, matrix metabolism, and cell death regulation.

The mechanisms and functions of TGF-ß1 in tendon healing.

Tendon injury accounts for 30% of musculoskeletal diseases and often leads to disability, pain, healthcare cost, and lost productivity. Following injury to tendon, tendon healing proceeds via three overlapping healing processes. However, due to the structural defects of the tendon itself, the tendon healing process is characterized by the formation of excessive fibrotic scar tissue, and injured tendons rarely return to native tendons, which can easily contribute to tendon reinjury. Moreover, the resulting fibrous scar is considered to be a precipitating factor for subsequent degenerative tendinopathy. Despite this, therapies are almost limited because underlying molecular mechanisms during tendon healing are still unknown. Transforming Growth Factor-ß1 (TGF-ß1) is known as one of most potent profibrogenic factors during tendon healing process. However, blockage TGF-ß1 fails to effectively enhance tendon healing. A detailed understanding of real abilities of TGF-ß1 involved in tendon healing can bring promising perspectives for therapeutic value that improve the tendon healing process. Thus, in this review, we describe recent efforts to identify and characterize the roles and mechanisms of TGF-ß1 involved at each stage of the tendon healing and highlight potential roles of TGF-ß1 leading to the fibrotic response to tendon injury.

From fetal tendon regeneration to adult therapeutic modalities: TGF-ß3 in scarless healing.

Tendon injuries are common disorders that can significantly impact people's lives. Unfortunately, the limited regenerative ability of tendons results in tissue healing in a scar-mediated manner. The current therapeutic strategies fail to fully recover the functions of the injured tendons, and as such, the conception of 'scarless healing' has gained prominent attention in the field of regenerative medicine. Interestingly, injured fetal tendons possess the capability to heal through regeneration, which builds an ideal blueprint for adult tendon regeneration. Studies have shown that fetal biochemical cues have the potential to improve adult tendon healing. Here we review the biological factors that contribute to fetal tendon regeneration and how manipulation of these biochemical cues in the adult tendon healing process could achieve regeneration.

We reviewed the biological factors that contribute to fetal tendon regeneration and how manipulation of these biochemical cues in the adult tendon healing process could achieve regeneration. The results showed that inflammation and TGF-ß level are the main elements involved in fetal tendon regeneration. Experimental manipulation of these biochemical cues in the adult tendon healing process demonstrated that although the blockade of TGF-ß1, TGF-ß2 and inflammation reduced scar tissue in adult tendon healing, this inhibition also destroyed the mechanical properties of the tendons. An effective alternative is regulating the specific downstream profibrotic effectors of both TGF-ß1 and inflammation, which is preferable to those that completely inhibit these factors. Finally, TGF-ß3 is a master regulator allowing a shift from adult scar healing to scarless healing, and the administration of TGF-ß3 is a viable strategy to promote adult regenerative healing. In terms of mechanisms, TGF-ß3 can activate Smad7 and inhibit the JNK/c-Jun signaling pathway to promote tendon regenerative healing.

Maternal adverse childhood experiences and behavioral problems in preschool offspring: the mediation role of parenting styles.

BACKGROUND: Maternal history of adverse childhood experiences (ACEs) has been found to be associated with children's health outcomes. However, the underlying mechanisms were unclear. This study aimed to examine the association between maternal ACEs and behavioral problems in their preschool offspring and to explore the potential mediating role of maternal parenting styles in the association. METHODS: A cross-sectional study was conducted involving 4243 mother-child dyads in Chengdu, China. Mothers completed the Adverse Childhood Experiences-International Questionnaire (ACE-IQ) to assess their history of ACEs (i.e., physical abuse, emotional abuse, physical neglect, emotional neglect, witnessing domestic violence, household substance abuse, household mental illness, incarcerated household member, parental separation or divorce, parental death, bullying, and community violence), the short Egna Minnen Beträffande Uppfostran Parent Form (S-EMBU-P) to evaluate their parenting styles (i.e., emotional warmth, rejection, and overprotection), and the 48-item Conners' Parent Rating Scale (CPRS-48) to measure behavioral problems in their children. Logistic regression models were established to examine the association between cumulative number of maternal ACEs and children's behavioral problems. The mediating role of parenting styles in this association was explored by generalized structural equation models (GSEM). RESULTS: Of the participating mothers, 85.8% (n = 3641) reported having experienced at least one type of ACE. Children of mothers with ≥2 ACEs showed a significantly increased risk of behavioral problems across all dimensions, including conduct problems, learning problems, psychosomatic problems, impulsive-hyperactive, anxiety, and hyperactivity index, in both crude and adjusted models (all p-values < 0.05). Dose-response patterns were also observed between the cumulative number of maternal ACEs and children's behavioral problems. In addition, maternal parenting styles of rejection emerged as a significant mediator, accounting for approximately 8.4-15.0% of the associations. CONCLUSIONS: Our findings indicated an intergenerational association of maternal ACEs with behavioral problems in preschool offspring, which was mediated by maternal parenting styles of rejection. Early screening and targeted intervention strategies are critical to mitigate the downstream consequences of maternal ACEs on young children's outcomes. Providing support and resources to improve parenting skills may prove beneficial.

Adverse childhood experiences, problematic internet use, and health-related quality of life in Chinese adolescents.

Background: The influence of adverse childhood experiences (ACEs) on an individual's health is substantial. However, the associations between ACEs, problematic internet use (PIU), and health-related quality of life (HRQOL) in adolescents remain underexplored.Objective: To assess the association between ACEs and HRQOL in Chinese adolescents and to evaluate the mediating role of PIU in this association.Method: A sample of 6,639 adolescents (3,457 boys and 3,182 girls) aged between 11-20 years (mean [SD] age: 14.5 [1.6] years) were recruited from 6 junior and senior middle schools using a proportional sampling approach in a cross-sectional study. Data on ACE exposure was collected through the short form of Childhood Trauma Questionnaire, the ACE-International Questionnaire, and two additional questions. HRQOL was assessed by the Pediatric Quality of Life Inventory version 4.0. The associations between ACEs and HRQOL were estimated using linear regression models. Mediation analysis was further conducted to explore the possible mediating role of PIU in the association between ACEs and HRQOL.Results: Our study collected 13 different ACEs. We found that adolescents exposed to any ACE had significantly lower scores in all HRQOL dimensions, psychosocial health summary scale, and total scale, than those without such exposure. Specifically, adolescents with ≥ 3 ACE exposure had a total scale score that was 14.70 (95%CI: 15.53 to 13.87) points lower than their non-exposed counterparts. Mediation analysis identified PIU as a significant mediator, with the proportion of the total effect attributable to PIU ranging from 14.38% for social functioning to 17.44% for physical functioning.Conclusions: Exposure to ACEs was associated with poorer HRQOL in Chinese adolescents, underscoring the importance to prevent ACEs and their negative impacts on adolescent well-being. These findings also highlighted the need of promoting appropriate internet use among adolescents exposed to ACEs, in order to avert potential impairment in their HRQOL.HIGHLIGHTSAdolescents with adverse childhood experiences have poorer health-related quality of life.The association between adverse childhood experiences and health-related quality of life shows a dose-response pattern.Problematic internet use partially mediates the associations between adverse childhood experiences and health-related quality of life in adolescents.

Associations between maternal parenting styles and preschool children s quality of life in Chengdu / 中国学校卫生

Objective@#To investigate the association between maternal parenting styles and quality of life among preschools，to provide a scientific theoretical basis for interventions targeting at prmoting early life health.@*Methods@#From May to July, 2021, a stratified cluster sampling method was used to enroll 4 233 child mother dyads from 14 preschools in Chengdu. An online questionnaire survey was administered to collect socio demographic information, maternal parenting styles, and children s quality of life.@*Results@#The overall score of quality of life was (80.17±9.81) among preschool children in Chengdu. In the multivariate linear regression models, maternal emotional warmth were significantly associated with higher scores in emotional functioning, social functioning, school functioning, psychosocial health summary score, and total scores ( β coefficients in the high level group were 2.63 , 4.95 , 12.05, 6.54,4.88, P <0.05). In contrast, both maternal rejection and overprotection were significantly associated with lower scores in physical functioning, emotional functioning, social functioning, school functioning, psychosocial health summary score, and the total scores of children s quality of life (for rejection: β coefficients in the high level group were -9.39, -10.82, -7.12 , -6.04 , -8.00, and -8.35 , respectively; for overprotection: β coefficients in the high level group were -6.71, -5.85, -3.08 , -2.39 , -3.77, and - 4.51 , respectively， P <0.05). The associations between high level of maternal rejection and children s emotional functioning showed significant gender differences( β =-3.23, P <0.05).@*Conclusion@#Maternal parenting style has a significant impact on children s quality of life. Interventions targeting at maternal parenting styles may be beneficial to improve the quality of life in preschool children.

Association between maternal intimate partner violence and health-related quality of life in their preschool children: The mediating role of maternal parenting styles.

Background: Although intimate partner violence (IPV) against women is a public health issue around the world, there is a lack of evidence regarding the impact of maternal IPV on preschool children's health-related quality of life (HRQOL). Therefore, the aim of this study was to investigate the association between maternal IPV and HRQOL among Chinese preschool children, as well as the mediating role of maternal parenting styles. Methods: A cross-sectional study was conducted with 4,243 mother-child dyads who attended preschools. Mothers self-reported their parenting styles and experience of IPV. Children's HRQOL was collected through mother-proxy report with the Pediatric Quality of Life Inventory version 4.0 (PedsQL 4.0). Multivariate linear regression analysis was conducted to evaluate the association between maternal IPV and children's HRQOL. Mediation models were further applied to explore the possible mediating role of maternal parenting styles. Results: Of the included mothers, 7.4% had experience of IPV. Compared to children of mothers without any IPV exposure, those of mothers with experience of IPV had significantly lower scores in all HRQOL dimensions and summary scales. After adjustment for covariates, maternal IPV was significantly associated with children's lower physical health summary score, psychosocial health summary score, and total scale score. Mediation analysis showed that both rejection and overprotection mediated such associations, but not for the emotional warmth. Conclusion: Our findings indicated the need to screen maternal IPV supplemented with targeted interventions focusing on parenting styles, in order to mitigate the negative impact of maternal IPV on children's HRQOL.

Genetics Responses to Hypoxia and Reoxygenation Stress in Larimichthys crocea Revealed via Transcriptome Analysis and Weighted Gene Co-Expression Network.

The large yellow croaker (Larimichthys crocea) is an important marine economic fish in China; however, its intolerance to hypoxia causes widespread mortality. To understand the molecular mechanisms underlying hypoxia tolerance in L. crocea, the transcriptome gene expression profiling of three different tissues (blood, gills, and liver) of L. crocea exposed to hypoxia and reoxygenation stress were performed. In parallel, the gene relationships were investigated based on weighted gene co-expression network analysis (WGCNA). Accordingly, the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that several pathways (e.g., energy metabolism, signal transduction, oxygen transport, and osmotic regulation) may be involved in the response of L. crocea to hypoxia and reoxygenation stress. In addition, also, four key modules (darkorange, magenta, saddlebrown, and darkolivegreen) that were highly relevant to the samples were identified by WGCNA. Furthermore, some hub genes within the association module, including RPS16, EDRF1, KCNK5, SNAT2, PFKL, GSK-3ß, and PIK3CD, were found. This is the first study to report the co-expression patterns of a gene network after hypoxia stress in marine fish. The results provide new clues for further research on the molecular mechanisms underlying hypoxia tolerance in L. crocea.

Hif-1α/Hsf1/Hsp70 signaling pathway regulates redox homeostasis and apoptosis in large yellow croaker ( Larimichthys crocea) under environmental hypoxia.

Oxygen is an essential molecule for animal respiration, growth, and survival. Unlike in terrestrial environments, contamination and climate change have led to the frequent occurrence of hypoxia in aquatic environments, thus impacting aquatic animal survival. However, the adaptative mechanisms underlying fish responses to environmental hypoxia remain largely unknown. Here, we used large yellow croaker ( Larimichthys crocea) and large yellow croaker fry (LYCF) cells to investigate the roles of the Hif-1α/Hsf1/Hsp70 signaling pathway in the regulation of cellular redox homeostasis, and apoptosis. We confirmed that hypoxia induced the expression of Hif-1α, Hsf1, and Hsp70 in vivo and in vitro. Genetic Hsp70 knockdown/overexpression indicated that Hsp70 was required for maintaining redox homeostasis and resisting oxidative stress in LYCF cells under hypoxic stress. Hsp70 inhibited caspase-dependent intrinsic apoptosis by maintaining normal mitochondrial membrane potential, enhancing Bcl-2 mRNA and protein expression, inhibiting Bax and caspase3 mRNA expression, and suppressing caspase-3 and caspase-9 activation. Hsp70 suppressed caspase-independent intrinsic apoptosis by inhibiting nuclear translocation of apoptosis-inducing factor (AIF) and disturbed extrinsic apoptosis by inactivating caspase-8. Genetic knockdown/overexpression of Hif-1α and dual-luciferase reporter assay indicated that Hif-1α activated the Hsf1 DNA promoter and enhanced Hsf1 mRNA transcription. Hsf1 enhanced Hsp70 mRNA transcription in a similar manner. In summary, the Hif-1α/Hsf1/Hsp70 signaling pathway plays an important role in regulating redox homeostasis and anti-apoptosis in L. crocea under hypoxic stress.

Scavenging reactive oxygen species is a potential strategy to protect Larimichthys crocea against environmental hypoxia by mitigating oxidative stress.

The large yellow croaker (Larimichthys crocea), which is an economically important mariculture fish in China, is often exposed to environmental hypoxia. Reactive oxygen species (ROS) homeostasis is essential for the maintenance of normal physiological conditions in an organism. Direct evidence that environmental hypoxia leads to ROS overproduction is scarce in marine fish. Furthermore, the sources of ROS overproduction in marine fish under hypoxic stress are poorly known. In this study, we investigated the effects of hypoxia on redox homeostasis in L. crocea and the impact of impaired redox homeostasis on fish. We first confirmed that hypoxia drove ROS production mainly via the mitochondrial electron transport chain and NADPH oxidase complex pathways in L. crocea and its cell line (large yellow croaker fry (LYCF) cells). We subsequently detected a marked increase in the antioxidant systems of the fish. However, imbalance between the pro-oxidation and antioxidation systems ultimately led to excessive ROS and oxidative stress. Cell viability showed a remarkable decrease while oxidative indicators, such as malondialdehyde, protein carbonylation, and 8-hydroxy-2 deoxyguanosine, showed a significant increase after hypoxia, accompanied by tissue damage. N-acetylcysteine (NAC) reduced ROS levels, alleviated oxidative damage, and improved cell viability in vitro. Appropriate uptake of ROS scavengers (e.g., NAC and elamipretide Szeto-Schiller-31) and inhibitors (e.g., apocynin, diphenylene iodonium, and 5-hydroxydecanoate) may be effective at overcoming hypoxic toxicity. Our findings highlight previously unstudied strategies of hypoxic toxicity resistance in marine fish.

Ultrastructure evidence for vesicles and double-membrane structures involved in cytoplasmic elimination during spermiogenesis in large yellow croaker, Larimichthys crocea (Teleostei, Perciformes, Scienidae).

Spermatids eliminate excess cytoplasm to form streamlined sperm during spermiogenesis, which mechanism is insufficiently elucidated in fish. In this study, we investigated the cytoplasmic elimination procedure in spermatid during spermiogenesis in the large yellow croaker (Larimichthys crocea) using transmission electron microscopy. The early spermatid is subrotund with a centrally located nucleus. With further development, nucleus polarizes into one side of the cell while the cytoplasm with numerous vesicles near the membrane migrates to the caudal region. Furthermore, exocytosis-like structures were detected in middle spermatid. In late spermatid, the vesicles are reduced and rarely observed. These findings indicate that vesicles may be involved in cytoplasmic elimination possibly via exocytosis. In the later spermatid, a double-membrane, autophagosome-like structure envelopes the cytoplasm, which may develop into a single-membrane structure, and gets discarded from the cell as a residual body from the caudal region. This suggests its potential functions in the formation of residual body and cytoplasmic elimination. Overall, our results revealed that polarized development of spermatid causes polarized distribution of cytoplasm necessary for cytoplasmic elimination. Moreover, they provide ultrastructure evidence for vesicles and double-membrane structures involved in discarding spermatid cytoplasm in large yellow croaker, thus offering novel insights into cytoplasmic elimination during spermiogenesis in fish.

Cloning, Functional Characterization and Response to Cadmium Stress of the Thioredoxin-like Protein 1 Gene from Phascolosoma esculenta.

Cadmium (Cd) is a heavy metal toxicant and is widely distributed in aquatic environments. It can cause excessive production of reactive oxygen species (ROS) in the organism, which in turn leads to a series of oxidative damages. Thioredoxin (Trx), a highly conserved disulfide reductase, plays an important role in maintaining the intracellular redox homeostasis in eukaryotes and prokaryotes. Phascolosoma esculenta is an edible marine worm, an invertebrate that is extensively found on the mudflats of coastal China. To explore the molecular response of Trx in mudflat organisms under Cd stress, we identified a new Trx isoform (Trx-like protein 1 gene) from P. esculenta for the first time, designated as PeTrxl. Molecular and structural characterization, as well as multiple sequence and phylogenetic tree analysis, demonstrated that PeTrxl belongs to the Trx superfamily. PeTrxl transcripts were found to be ubiquitous in all tissues, and the highest expression level occurred in the coelomic fluid. Exposure to three sublethal concentrations of Cd resulted in the upregulation and then downregulation of PeTrxl expression levels over time in coelomic fluid of P. esculenta. The significant elevation of PeTrxl expression after 12 and 24 h of Cd exposure at 6 and 96 mg/L, respectively, might reflect its important role in the resistance to Cd stress. Recombinant PeTrxl (rPeTrxl) showed prominent dose-dependent insulin-reducing and ABTS free radical-scavenging abilities. After exposure to 96 mg/L Cd for 24 h, the ROS level increased significantly in the coelomic fluid, suggesting that Cd induced oxidative stress in P. esculenta. Furthermore, the injection of rPeTrxl during Cd exposure significantly reduced the ROS in the coelomic fluid. Our data suggest that PeTrxl has significant antioxidant capacity and can protect P. esculenta from Cd-induced oxidative stress.

Developmental and mRNA transcript relative abundance pattern of vitellogenin receptors, LR8-/Lrp13, during ovarian development in the large yellow croaker (Larimichthys crocea).

For vitellogenin (Vtg) absorption to occur, there needs to binding of the glycolipophosphoproteins to the oocyte membrane in oviparous species, including teleosts. The cDNAs encoding homologous Vtg receptors (VgRs) LR8- and Lrp13 were cloned from ovaries of the large yellow croaker (Larimichthys crocea), an economically important species in Chinese aquaculture. The full-length Lc-lr8-/lrp13 cDNAs contained 4266/3760 base pairs (bp) and the deduced Lc-LR8-/Lrp13 proteins had 844/1218 amino acids, respectively. The VgRs comprised a ligand-binding domain, an epidermal growth factor precursor homology domain, YWXD motifs forming a ß-propeller structure, and transmembrane and cytoplasmic domains. There was a marked relative abundance of Lc-lr8-/lrp13 transcripts in the tissues that were evaluated, with the largest abundance in the ovaries at Stage II of development. Furthermore, there was a lesser relative abundance of Lc-lr8-/lrp13 mRNA transcript during ovarian development (Stages II to IV). In situ hybridization technology was used to analyze decreasing relative abundance pattern of Lc-lr8-/lrp13 mRNA transcript during oogenesis in Stage II to IV of ovarian development. By combining mRNA relative abundance with morphological results, a model was developed to explain the reduction in Lc-lr8-/lrp13 mRNA transcript relative abundance during ovarian development. During the early developmental stages, transcription, translation, and differential accumulation of VgRs in previtellogenic and vitellogenic oocytes may occur and result in Vtg absorption in teleost oocytes. Overall, there is preliminary evidence indicating that at least two VgRs (Lc-LR8-/Lrp13) are present in the large yellow croaker and may be important for Vtg transport from the blood into the oocyte during ovarian development.

Transcriptome and physiology analysis identify key metabolic changes in the liver of the large yellow croaker (Larimichthys crocea) in response to acute hypoxia.

The large yellow croaker (Larimichthys crocea) is one of the most important marine economic fish in the southeast coast of China. However, hypoxia stress become a major obstacle to the benign development of L. crocea industry. To understand the energy metabolism mechanism adapted to hypoxia, we analyzed the transcriptome and physiology of L. crocea liver in response to hypoxia stress for different durations. We obtained 243,756,080 clean reads, of which 83.38% were successfully mapped to the reference genome of L. crocea. The heat map analysis showed that genes encoding enzymes involved in glycolysis/gluconeogenesis were significantly upregulated at various time points. Moreover, genes encoding enzymes related to the citrate cycle, oxidative phosphorylation, and amino acid metabolism were significantly downregulated at 6 and 24 h, but upregulated at 48 and 96 h. The change of liver in physiology processes, including respiratory metabolism, and activities of the carbohydrate metabolism enzymes showed a similar trend. The results revealed that the respiratory metabolism of L. crocea was mainly anaerobic within 24 h of hypoxia stress, and aerobic metabolism was dominant after 24 h. Carbohydrate metabolism plays a crucial role in energy supply and amino acid metabolism is an important supporting character to cope with acute hypoxia stress. There was no significant change in lipid utilization under short-term acute stress. This study increases our understanding of the energy metabolism mechanism of the hypoxia response in fish and provides a useful resource for L. crocea genetics and breeding.

Transcriptome Sequencing Reveals the Traits of Spermatogenesis and Testicular Development in Large Yellow Croaker (Larimichthys crocea).

Larimichthys crocea is an economically important marine fish in China. To date, the molecular mechanisms underlying testicular development and spermatogenesis in L. crocea have not been thoroughly elucidated. In this study, we conducted a comparative transcriptome analysis between testes (TES) and pooled multiple tissues (PMT) (liver, spleen, heart, and kidney) from six male individuals. More than 54 million clean reads were yielded from TES and PMT libraries. After mapping to the draft genome of L. crocea, we acquired 25,787 genes from the transcriptome dataset. Expression analyses identified a total of 3853 differentially expressed genes (DEGs), including 2194 testes-biased genes (highly expressed in the TES) and 1659 somatic-biased genes (highly expressed in the PMT). The dataset was further annotated by blasting with multi-databases. Functional genes and enrichment pathways involved in spermatogenesis and testicular development were analyzed, such as the neuroactive ligand-receptor interaction pathway, gonadotropin-releasing hormone (GnRH) and mitogen-activated protein kinase (MAPK) signaling pathways, cell cycle pathway, and dynein, kinesin, myosin, actin, heat shock protein (hsp), synaptonemal complex protein 2 (sycp2), doublesex- and mab-3-related transcription factor 1 (dmrt1), spermatogenesis-associated genes (spata), DEAD-Box Helicases (ddx), tudor domain-containing protein (tdrd), and piwi genes. The candidate genes identified by this study lay the foundation for further studies into the molecular mechanisms underlying testicular development and spermatogenesis in L. crocea.

Transcriptional response to low temperature in the yellow drum (Nibea albiflora) and identification of genes related to cold stress.

The yellow drum (Nibea albiflora) is an economically important maricultured fish in China, but the aquaculture of this species is severely affected by overwinter mortality associated with cold stress. Characterization of the molecular mechanisms underlying the susceptibility of the yellow drum to cold might increase our understanding of how this fish adapts to environmental challenges. Here, the transcriptional response of the yellow drum to cold stress (7.5 °C) was investigated with RNA-Seq analysis. We compared brain and muscle transcriptomes among cold-tolerant (Tol) fish that survived the cold treatment, cold-sensitive (Sen) fish that were killed by the cold treatment, and control (Con) fish that were not subjected to cold. Our analysis recovered 233,245 unigenes. The genes (DEGs) differentially expressed in the brain and muscle of the Tol versus Con group, the Sen versus Con group, and the Tol versus Sen group had tissue-specific expression patterns. Gene ontology, enrichment, and pathway analyses indicated the most highly enriched pathways in the DEGs were signaling molecules and interaction, signal transduction, carbohydrate metabolism, lipid metabolism, digestive system, and endocrine system pathways. These pathways were all associated with biological functions relevant to cold adaptation in the yellow drum, including transduction of stress signals, energy metabolism, and stress-induced cell membrane changes. We identified genes likely to be involved in cold-susceptibility and -tolerance as those differentially expressed in the Tol group as compared to the Sen group. Further investigation and characterization of these candidate genes might improve our understanding of the mechanisms underlying cold adaptation in the yellow drum.