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The sea cucumber Apostichopus japonicus is an economically important marine species in China, and understanding the mechanisms underlying its gonad development is crucial for successful reproduction and breeding. In this study, we performed transcriptome comparisons and analyses of A. japonicus gonadal and non-gonadal tissues to identify genes and molecular pathways associated with gonadal development. We also supplemented the annotation of the A. japonicus genome. Collectively, results revealed a total of 941 ovary-specific genes and 2499 testis-specific genes through different expression analysis and WGCNA analysis. The most enriched pathways in ovary and testis were "DNA replication" and "purine metabolism", respectively. Additionally, we identified key candidate gene modules that control gonad development and germ cell maturation, with CDT1 and DYNC2LI1 serving as hub genes. Our findings provide important insights into the gonadal development system of A. japonicus and offer valuable references for further research on reproductive biology in this marine invertebrate species. [Display omitted] • Comparative analyses of gene expression in sea cucumber gonadal and non-gonadal tissues • Key candidate gene modules specifically expressed by females and males gonad were screened. • The ovarian module with CDT1 as the core gene may affect ovarian development through the pre-replication complex. [ABSTRACT FROM AUTHOR]

Background/Aims: Spinal cord injury (SCI) is a serious global problem that leads to permanent motor and sensory deficits. This study explores the anti-apoptotic and neuroprotective effects of the natural extract β-elemene in vitro and in a rat model of SCI. Methods: CCK-8 assay was used to evaluate cell viability and lactate dehydrogenase assay was used to evaluate cytotoxicity. A model of cell injury was established using cobalt chloride. Apoptosis was evaluated using a fluorescence-activated cell sorting assay of annexin V-FITC and propidium iodide staining. A rat SCI model was created via the modified Allen’s method and Basso, Beattie, and Bresnahan (BBB) scores were used to assess locomotor function. Inflammatory responses were assessed via enzyme-linked immunosorbent assay (ELISA). Apoptotic and surviving neurons in the ventral horn were respectively observed via terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and Nissl staining. Western blotting was used to measure protein expression. Results: β-elemene (20 μg/ml) promoted cell viability by activating phosphorylation of the PI3K-AKT-mTOR pathway. β-elemene reduced CoCl2-induced cellular death and apoptosis by suppressing the expression levels of CHOP, cleaved-caspase 12, 78-kilodalton glucose-regulated protein, cleaved-caspase 3, and the Bax/Bcl-2 ratio. In the rat model of SCI, Nissl and TUNEL staining showed that β-elemene promoted motor neuron survival and reduced neuronal apoptosis in the spinal cord ventral horn. BBB scores showed that β-elemene significantly promoted locomotor behavioral recovery after SCI. In addition, β-elemene reduced the ELISA-detected secretion of interleukin (IL)-6 and IL-1β. Conclusion: β-elemene reduces neuronal apoptosis by alleviating endoplasmic reticulum stress in vitro and in vivo. In addition, β-elemene promotes locomotor function recovery and tissue repair in SCI rats. Thus, our study provides a novel encouraging strategy for the potential treatment of β-elemene in SCI patients. [ABSTRACT FROM AUTHOR]

Sea cucumber Apostichopus japonicus displays the typical circadian rhythms. This present study investigated the molecular regulation of clock genes, as well as monoamines and melatonin, in multiple tissues of A. japonicus , responding to the photoperiod. In order to determine their pivotal role in circadian rhythms, the crucial clock genes, namely AjClock , AjArnt1 , AjCry1 , and AjTimeless , were identified and a comprehensive analysis of their expressions across various tissues in adult A. japonicus was conducted, revealing the potential existence of central and peripheral oscillators. Results demonstrated that the tissues of polian vesicle and nerve ring exhibited significant clock gene expression associated with the orchestration of circadian regulation, and that environmental light fluctuations exerted influence on the expression of these clock genes. However, a number of genes, such as AjArnt1 and AjCry1 , maintained their circadian rhythmicity even under continuous light conditions. Moreover, we further investigated the circadian patterns of melatonin (MT), serotonin (5-HT), and dopamine (DA) secretion in A. japonicus , data that underscored the tissue-specific regulatory differences and the inherent adaptability to dynamic light environments. Collectively, these findings will provide the molecular mechanisms controlling the circadian rhythm in echinoderms and the candidate tissues playing the role of central oscillators in sea cucumbers. [Display omitted] • The molecular circadian system was identified in Apostichopus japonicus. • The polian vesicle and nerve ring were determined with roles as circadian oscillators. • A. japonicus circadian system exhibits stability. • The rhythmicity of molecular circadian system can be affected by photoperiods. [ABSTRACT FROM AUTHOR]