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Abstract Background Global warming-induced environmental stresses have diverse effects on gene expression and regulation in the life processes of various aquatic organisms. N6 adenylate methylation (m6A) modifications are known to influence mRNA transcription, localization, translation, stability, splicing, and nuclear export, which are pivotal in mediating stress responses. Apostichopus japonicus is a significant species in aquaculture and a representative of benthic organisms in ecosystems, thus there is a growing need for research on its heat stress mechanism. Results In this study, m6A-modified whole transcriptome profiles of the respiratory tree tissues of A. japonicus in the control (T18) and high-temperature stress (T32) groups were obtained using MeRIP-seq technology. The results showed that 7,211 common m6A peaks, and 9,459 genes containing common m6A were identified in three replicates T18 and T32 groups. The m6A peaks were found to be highly enriched in the 3’ untranslated region, and the common sequence of the m6A peak was also enriched, which was shown as RRACH (R = G or A; H = A, C, or U). A total of 1,200 peaks were identified as significantly differentially enriched in the T32 group compared with the T18 group. Among them, 245 peaks were upregulated and 955 were downregulated, which indicated that high temperature stress significantly altered the methylation pattern of m6A, and there were more demethylation sites in the T32 group. Conjoint analysis of the m6A methylation modification and the transcript expression level (the MeRIP-seq and RNA-seq data) showed co-differentiated 395 genes were identified, which were subsequently divided into four groups with a predominant pattern that more genes with decreased m6A modification and up-regulated expression, including HSP70IV, EIF2AK1, etc. GO enrichment and KEGG analyses of differential m6A peak related genes and co-differentiated genes showed the genes were significantly associated with transcription process and pathways such as protein processing in the endoplasmic reticulum, Wnt signaling pathway, and mTOR signaling pathway, etc. Conclusion The comparisons of m6A modification patterns and conjoint analyses of m6A modification and gene expression profiles suggest that m6A modification was involved in the regulation of heat stress-responsive genes and important functional pathways in A. japonicus in response to high-temperature stress. The study will contribute to elucidate the regulatory mechanism of m6A modification in the response of A. japonicus to environmental stress, as well as the conservation and utilization of sea cucumber resources in the context of environmental changes.

Objective: Osteoarthritis (OA) is a chronic degenerative joint disease characterized by cartilage damage. In order to find a safer and more effective drug to treat OA, we investigated the role of quercetin-3-O-β-D-glucuronide (Q3GA) in OA. Methods: We used qRT-PCR and western blots to detect the effects of Q3GA on extracellular matrix (ECM) and inflammation related genes and proteins in interleukin-1β (IL-1β) induced chondrocytes. We determined the effect of Q3GA on the NF-κB pathway using western blots and immunofluorescence. Moreover, the effect of Q3GA on the Nrf2 pathway was evaluated through molecular docking, western blots, and immunofluorescence experiments and further validated by transfection with Nrf2 siRNA. Subsequently, we established a rat model of OA and injected Q3GA into the joint cavity for treatment. After 5 weeks of Q3GA administration, samples were obtained for micro-computed tomography scanning and histopathological staining to determine the effects of Q3GA on OA rats. Results: We found that Q3GA reduced the degradation of ECM and the expression of inflammatory related proteins and genes in primary chondrocytes of rats induced by IL-1β, as well as the expression of nitric oxide (NO) and reactive oxygen species (ROS). It inhibited the activation of the NF-κB pathway by increasing the expression of Nrf2 in the nucleus. In addition, Q3GA inhibited cartilage degradation in OA rats and promoted cartilage repair. Conclusion: Q3GA attenuates OA by inhibiting ECM degradation and inflammation via the Nrf2/NF-κB axis. The translational potential of this article: The results of our study demonstrate the promising potential of Q3GA as a candidate drug for the treatment of OA and reveal its key mechanisms.

Pathogenic infections significantly limit the culture of marine organisms, such as cephalopods. However, there is a lack of immune information regarding cephalopods to address pathogen problems. Polyriboinosinic polyribocytidylic acid (Poly I:C), a synthetic virus-like molecule, can be recognized by the immune cells as pathogen-associated molecular patterns (PAMPs), and this process is often used to simulate the invasion of viruses. The white body is an immune and hematopoietic organ, and its RNA-seq information obtained from Amphioctopus fangsiao stimulated by Poly I:C is essential for understanding the antiviral immune response in this species. In this research, we performed transcriptome sequencing and bioinformatics analysis of A. fangsiao white body tissue within 24 h stimulated by Poly I:C. A large number of differentially expressed genes (DEGs) were detected in this study, including 2,613 and 8 DEGs at 6 h and 24 h, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used for searching immune-related terms and genes. A protein–protein interaction (PPI) network was constructed to identify the relationship between immune genes. Finally, the 20 hub genes including RAC1, MAPK14, PIK3CA and other seventeen hub genes were identified based on the network and pathway analyses, and we validated the accuracy of 20 hub genes using qRT-PCR. These hub genes mainly participated in PI3K-Akt signaling pathway, Chemokine signaling pathway and other signaling pathways, in addition to the ubiquitin family. These research results provided a valuable theoretical basis for researching A. fangsiao white body immunity and significantly improved our cognition about innate immunity of cephalopods.

Sepia esculenta is a tasty and nutritious cephalopod. But the trend toward global warming is accelerating with massive emissions of greenhouse gases. An increase in seawater temperature and a decrease in pH are a great challenge for artificial breeding and culture of S. esculenta. In this study, we investigated the contingency mechanism of S. esculenta larvae under both high temperature and low pH conditions by transcriptome analysis. A total of 1235 DEGs were identified. functional enrichment analysis results suggest that high temperature and low pH conditions led to malignant proliferation in exceptional cells of S. esculenta larvae. A comprehensive analysis of the KEGG signaling pathway and protein-protein interaction network (PPI) identified sixteen key genes under both high temperature and low pH conditions. The three genes with the highest quantities of interactions or involved in more KEGG signaling pathways were identified as hub genes affecting normal physiological processes in S. esculenta. In this study, the effects of global warming and ocean acidification on the metabolism and immunity of S. esculenta larvae were preliminarily investigated to provide necessary help for S. esculenta captive breeding in the face of global climate change.

Spermatogenesis is the production of spermatozoa by the testes, a process that is associated with reproduction in males. Amphioctopus fangsiao is an economically important species from the northern coast of China, and little research has been done on spermatogenesis in this species. In this study, we performed transcriptome analysis of testis and other somatic tissues. The maturing stage of testis development was selected, in which the emergence of spermatozoa was observed. A total of 15,773 differentially expressed genes were identified, including 8,922 upregulated genes and 6,851 downregulated genes. GO and KEGG enrichment analyses were performed to explore the functions of genes related to spermatogenesis, and the interactions between genes were examined by constructing protein interaction networks. Pathways and genes related to spermatogenesis were identified, including the oxytocin signaling pathway, the calcium signaling pathway, the FOXO signaling pathway, the DNAH family, and other key genes. The expression levels of 25 key genes were verified by qRT-PCR. The results for spermatogenesis-related genes will provide insights into the processes of spermatogenesis and testis development in A. fangsiao.

Marine mollusks, including oysters, are highly tolerant to high levels of cadmium (Cd), but the molecular mechanisms underlying their molecular response to acute Cd exposure remain unclear. In this study, the Pacific oyster Crassostrea gigas was used as a biological model, exposed to acute Cd stress for 96 h. Transcriptomic analyses of their gills were performed, and metabolomic analyses further validated these results. In our study, a total of 111 differentially expressed metabolites (DEMs) and 2108 differentially expressed genes (DEGs) were identified under acute Cd exposure. Further analyses revealed alterations in key genes and metabolic pathways associated with heavy metal stress response. Cd exposure triggered physiological and metabolic responses in oysters, including enhanced oxidative stress and disturbances in energy metabolism, and these changes revealed the biological response of oysters to acute Cd stress. Moreover, oysters could effectively enhance the tolerance and detoxification ability to acute Cd exposure through activating ABC transporters, enhancing glutathione metabolism and sulfur relay system in gill cells, and regulating energy metabolism. This study reveals the molecular mechanism of acute Cd stress in oysters and explores the molecular mechanism of high tolerance to Cd in oysters by using combined metabolomics and transcriptome analysis.

Near-infrared spectroscopy (NIR) has become an essential tool for non-destructive analysis in various fields, including aquaculture. This study presents a pioneering application of portable NIR spectrometers to analyze glycogen content in the gonadal tissues of the Pacific oyster (Crassostrea gigas), marking the first instance of developing quantitative models for glycogen in tetraploid C. gigas. The research also provides a comparative analysis with models for diploid and triploid oysters, underscoring the innovative use of portable NIR technology in aquaculture. Two portable NIR spectrometers were employed: the Micro NIR 1700 (908–1676 nm) and the Micro PHAZIR RX (1624–2460 nm). Near-infrared spectra were acquired from the gonadal tissues of diploid, triploid, and tetraploid C. gigas. Quantitative models for glycogen content were developed and validated using cross-validation methods. Additionally, qualitative models for different ploidies and genders were established. For the Micro NIR 1700, the cross-validation correlation coefficients (Rcv) and cross-validation relative predictive errors (RPDcv) for glycogen were 0.949 and 3.191 for diploids, 0.915 and 2.498 for triploids, and 0.902 and 2.310 for tetraploids. The Micro PHAZIR RX achieved Rcv and RPDcv values of 0.781 and 2.240 for diploids, 0.839 and 2.504 for triploids, and 0.717 and 1.851 for tetraploids. The Micro NIR 1700 demonstrated superior quantitative performance, with RPD values exceeding 2, indicating its effectiveness in predicting glycogen content across different ploidy levels. Qualitative models showed a performance index of 91.6 for diploid and 95 for tetraploid genders using the Micro NIR 1700, while the Micro PHAZIR RX achieved correct identification rates of 99.79% and 100% for diploid and tetraploid genders, respectively. However, differentiation of ploidies was less successful with both instruments. This study’s originality lies in establishing the first quantitative models for glycogen content in tetraploid C. gigas using portable NIR spectrometers, highlighting the significant advancements in non-destructive glycogen analysis. The applicability of these findings is substantial for oyster breeding programs focused on enhancing meat quality traits. These models provide a valuable phenotyping tool for selecting oysters with optimal glycogen content, demonstrating the practical utility of portable NIR technology in aquaculture.

Over the years, oysters have faced recurring mass mortality issues during the summer breeding season, with Vibrio infection emerging as a significant contributing factor. Tubules of gill filaments were confirmed to be in the hematopoietic position in Crassostrea gigas, which produce hemocytes with immune defense capabilities. Additionally, the epithelial cells of oyster gills produce immune effectors to defend against pathogens. In light of this, we performed a transcriptome analysis of gill tissues obtained from C. gigas infected with Vibrio alginolyticus for 12 h and 48 h. Through this analysis, we identified 1024 differentially expressed genes (DEGs) at 12 h post-injection and 1079 DEGs at 48 h post-injection. Enrichment analysis of these DEGs revealed a significant association with immune-related Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. To further investigate the immune response, we constructed a protein–protein interaction (PPI) network using the DEGs enriched in immune-associated KEGG pathways. This network provided insights into the interactions and relationships among these genes, shedding light on the underlying mechanisms of the innate immune defense mechanism in oyster gills. To ensure the accuracy of our findings, we validated 16 key genes using quantitative RT-PCR. Overall, this study represents the first exploration of the innate immune defense mechanism in oyster gills using a PPI network approach. The findings provide valuable insights for future research on oyster pathogen control and the development of oysters with enhanced antimicrobial resistance.

The emergence of triploid oysters has freed the oyster market from the problem of interruptions in the breeding season, allowing for year-round availability. However, according to recent statistics, the phenomenon of fertility in triploid oysters has been increasing yearly, perhaps eventually leading to the loss of the sterility characteristic. This has in turn affected the oyster farming industry. Therefore, we attempted to mine key genes through transcriptomics to find the causes of triploid fertility. During our surveys and sampling, we found that most of the fertile triploid Crassostrea gigas were females, with a much smaller percentage of males. Therefore, the main objective of this study was to analyze the differences between fertile and sterile triploid female C. gigas. We performed transcriptome analysis of fertile female triploid C. gigas and sterile female triploid C. gigas and identified 2361 up-regulated differentially expressed genes (DEGs) and 1541 down-regulated DEGs, respectively. Enrichment analysis of these DEGs revealed that most GO terms and KEGG pathways were associated with mitosis. We then created a protein–protein interaction (PPI) network using genes enriched in mitosis-associated KEGG pathways. Finally, we screened and validated 26 key genes by quantitative RT-PCR and all were found to be downregulated in expression in sterile female triploids. The main cause of sterility is the suppression of the expression of genes that control the process of germ cell proliferation, the failure of the mitotic cycle to proceed smoothly, and the inability to produce an oogonium. These results can be used to explore ways to reduce the fertility of triploid C. gigas and to promote the breeding of higher quality triploid oysters.

This paper proposes an improved Sparrow Search Algorithm based on the self-avoiding random walk strategy as a fuzzy control method (SAWS-SSA) for rig winch motors in the complex oil rig electric control industry. The SAWS-SSA aims to accurately describe the system dynamics and improve the motor performance despite the large number of control-winch variables. During the startup of the three-phase asynchronous motor of the winch, the error value between the current feedback and thyristor trigger angle coupled with the periodic change rate was used as the input for the fuzzy control start. The fuzzy rules progressively reduce the components of the excitation current and iteratively calculate the difference between the input and feedback of the active power until the motor speed and torque are stabilized. To reduce the evaluation time of the optimization search, we optimized the heuristic affiliation function variables using an improved sparrow search algorithm equipped with a self-avoidance random walks strategy. Experimental verification confirms that SAWS-SSA outperforms other control algorithms in terms of the statistical error in the instantaneous dynamic response of the oil rig winch under a constant load and at different speeds.

Sperm storage is an important reproductive strategy in Amphioctopus fangsiao. Sperm can be stored in the oviducal glands up to eight months before fertilization. However, studies on the underlying storage mechanisms remain limited. In this study, the morphological structures of the oviductal glands and the changes adapted for sperm storage and fertilization were investigated by Hematoxylin eosin (HE) staining, transmission electron microscopy (TEM), and Alcian blue periodic acid Schiff (AB-PAS) staining. Results revealed that the nucleo-cytoplasmic ratio of the peripheral gland cells decreased and the eosinophilic secretory granules (glycoproteins) appeared in the cytoplasm and lumen during sperm storage. The cytoplasm of the central gland appeared vacuolated and AB pH 2.5 (+) secretions (acid mucins) were dispersed in the cells. These secretions may pass through the central cavity into the oviducts and be involved in zygote packaging. The spermathecae are composed of columnar epithelial ciliated cells with secretory functions. PAS (+) glycoproteins were found in the lumen, providing a microenvironment conducive to sperm survival. Cilia in the oviducts, central cavity, and spermathecae may help with sperm delivery, storage, and release, and egg transport. This study enhances our understanding of the biological reproduction process in A. fangsiao.

Sea cucumber Apostichopus japonicus, an important marine benthic animal, is particularly sensitive to environmental temperature stress, which affected the growth, metabolism, and reproduction even survival. In this study, we used whole genome bisulfite sequencing (WGBS) to perform a comprehensive comparative analysis of the DNA methylation profiles of A. japonicus at three temperatures: normal (20 °C), aestivation (26 °C), and lethal (32 °C). The results showed that the total methylation level was highest in group T26 and lowest in group T32. Most of the DNA methylation occurred on the C bases of the CG type, and the degree of DNA methylation on the CG-type C bases was 13.32–14.99%, reflecting a moderate level of DNA methylation. Comparison of differentially methylated regions (DMRs) in the CG sequence context, we identified 17,174 DMRs in group T26_vs_T20 and 16,216 DMRs in group T32_vs_T26. There were more hypermethylated regions than hypomethylated regions, and this difference was more obvious in group T32_vs_T26. DMRs analysis of the promoter regions and the gene body regions identified more DMR-related genes in the gene body region than in the promoter region in both comparison groups (T26_vs_T20 and T32_vs_T26). GO and KEGG analysis showed that pathways such as protein processing in the endoplasmic reticulum, ubiquitin mediated proteolysis, and endocytosis, etc., were highly enriched in the DMR-related genes in the comparison groups. Some of these pathways that were significantly enriched in the hypermethylated genes in group T26_vs_T20 but were enriched in the hypomethylated genes in group T32_vs_T26. Enrichment analysis of genes both differentially methylated and differentially expressed showed that downregulated genes in group T32_vs_T26 that were also hypomethylated in the gene body region were significantly enriched in the metabolic and the antioxidant-related glutathione metabolism pathway. Our results suggested that DNA methylation develop a lot of variation in the regulation of the response of A. japonicus to two levels of heat stress: at aestivation temperature and at lethal temperature, and there are many differences between the two. The results of this study provide important insights into the epigenetic mechanisms underlying the response of A. japonicus to the pressure of environmental temperature.

Semicarbazide (SMC), also known as carbamoyl hydrazide, is a key intermediate for the organic synthesis of drugs, pesticides, and a panoply of other applications. It is also regarded as a landmark metabolite of nitrofurazone, a banned veterinary drug. SMC produced in different ways will eventually enter the ocean and become an emerging marine pollutant, affecting the physiological metabolism, behavioral activities, and even survival of aquatic organisms. Sea cucumbers are sediment-feeding organisms, and their risk of exposure to pollutants has attracted increasing attention. In this study, an integrated proteomic and metabolomic approach was used to investigate the responses of Apostichopus japonicus treated with SMC (3.72 g/L) for 72 h. After SMC treatment, the proteins and metabolites of A. japonicus intestine changed significantly. The results showed that 342 differentially expressed proteins were identified, of which 174 were upregulated, 168 were downregulated, and 74 differentially expressed metabolites, of which 62 were upregulated and 12 were downregulated. These differential proteins and metabolites were primarily involved in energy metabolism, lipid metabolism, signal transduction, immune regulation, autophagy, and apoptosis. On the basis of a combination of proteomic and metabolomic data, a hypothetical network of proteins, metabolites, and pathways in sea cucumbers was also described; the resulting network indicated several significant biological activities in response to SMC. This work offers a thorough analysis of the intricate mechanisms by which sea cucumbers respond to SMC stress and indicates numerous possible indicators for further research on creatures exposed to SMC. Further, our results provide scientific guidance for pollution control of Apostichopus japonicus culture to ensure healthy breeding.

Sepia esculenta is an economically important mollusk distributed in the coastal waters of China. Juveniles are more susceptible to stimulation by the external environment than mature individuals. The ocean salinity fluctuates due to environmental changes. However, there is a lack of research on the salinity adaptations of S. esculenta. Therefore, in this study, we investigated the differential expression of genes in S. esculenta larvae after stimulation by low salinity. RNA samples were sequenced and 1039 differentially expressed genes (DEGs) were identified. Then, enrichment analysis was performed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Finally, a protein–protein interaction network (PPI) was constructed, and the functions of key genes in S. esculenta larvae after low-salinity stimulation were explored. We suggest that low salinity leads to an excess proliferation of cells in S. esculenta larvae that, in turn, affects normal physiological activities. The results of this study can aid in the artificial incubation of S. esculenta and reduce the mortality of larvae.

In this study, diploid, triploid, and tetraploid Crassostrea gigas samples were subjected to gas chromatography and ion mobility (GC-IMS) to identify and analyze volatile compounds and flavor fingerprints under conditions of high-temperature incubation. The GC-IMS technology identified a total of 54 volatile components in C. gigas. The contents of 1-octen-3-ol, butyl pentanoate, p-methyl anisole, and 2-methyl-2-hepten-6-one in male oysters were significantly higher than in females, while the contents of phenylacetaldehyde, benzaldehyde, 2-ethyl-3-methylpyrazine, 2-ethylfuran, and 2,4-hexadienal in female oysters were significantly higher than in males. The contents of non-3-en-2-one-M and 1-pentanol in diploids were significantly higher than in triploids and tetraploids, while the content of 2,4-hexadienal in tetraploids was significantly higher than in diploids and tetraploids. The contents of ethyl acetate, ethyl-2-butenoate, and butanal in tetraploids were significantly higher than those in diploids and triploids. The results of a principal components analysis showed that different samples were relatively independently clustered, allowing the ability to distinguish different oyster samples. The chemical fingerprints of volatile compounds of C. gigas with different ploidy and gender under high-temperature incubation were established, and the volatile substance contours of C. gigas were visualized. The results provide a reference for distinguishing the ploidy and gender of C. gigas under conditions of high-temperature incubation.

Sepia esculenta is a popular economic cephalopod with high yield, delicious meat, and rich nutrition. With the rapid development of heavy industry and medical industry, a large amount of waste has been released into the ocean recklessly in recent years, inducing a significant increase in the content of heavy metals, especially cadmium (Cd) and copper (Cu), in the ocean. This phenomenon significantly affects the growth and development of S. esculenta, causing a serious blow to its artificial breeding. In this study, transcriptome analysis is used to initially explore immune response mechanisms of Cd and Cu co-exposed juvenile S. esculenta. The results show that 1,088 differentially expressed genes (DEGs) are identified. And DEGs functional enrichment analysis results suggests that co-exposure may promote inflammatory and innate immune responses in juvenile S. esculenta. Fifteen key genes that might regulate the immunity of S. esculenta are identified using protein-protein interaction (PPI) network and KEGG enrichment analyses, of which the three genes with the highest number of interactions or involve in more KEGG pathways are identified as hub genes that might significantly affect the immune response processes. Comprehensive analysis of PPI network and KEGG signaling pathway is used for the first time to explore co-exposed S. esculenta juvenile immune response processes. Our results preliminarily reveal immune response mechanisms of cephalopods exposed to heavy metals and provide a valuable resource for further understanding of mollusk immunity.

Mass mortalities of oysters during the summer have been reported for years. Among the biological factors causing oyster death in summer, Vibrio infection is considered to be the most important factor. Vibrio alginolyticus is one of the main pathogens causing oyster diseases. V. alginolyticus can cause disease and death of fish, shrimp, shellfish, and other aquatic products. Human infection with V. alginolyticus can also cause skin infections, external ear canal infections, and other diseases. Hemocytes in the blood of Crassostrea gigas resemble vertebrate macrophages and play an important role in the immune regulation of organisms. Therefore, it is of great significance to analyze the blood transcriptome to study the anti-pathogen mechanism of the C. gigas. In our study, we performed a transcriptome profile of gene expression on C. gigas infected with V. alginolyticus at 12 and 48 hours, and identified 2,494 and 1,165 differentially expressed genes (DEGs) at two sampling time points. Then, the functions of DEGs were identified using GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) functional enrichment analysis, revealing that there were multiple significantly enriched GO terms and KEGG signaling pathways related to immunity. And a protein-protein interaction (PPI) network was construct using DEGs enriched in significant enriched immune-related KEGG signaling pathways. At last, we screened and validated 12 key genes with multiple protein interaction numbers or involved in more KEGG signaling pathways, and verified their expression changes by quantitative RT-PCR (qRT-PCR). For the first time, we studied the immune defense mechanism of C. gigas blood based on protein-protein interaction network, which explains how C. gigas lacking specific immunity survive in a pathogen-rich environment. This research provides reference for solving the problem of high mortality of C. gigas and other mollusks in summer, and provides reference for the future production of some disease-resistant C. gigas.

As a common and high-concentration heavy metal in the ocean, Cu can induce metal toxicity and significantly affect the metabolic function of marine organisms. Sepia esculenta is an important economic cephalopod found along the east coast of China, the growth, movement, and reproduction of which are all affected by heavy metals. Hitherto, the specific metabolic mechanism of heavy-metal exposure in S. esculenta is still unclear. In this study, we identified 1131 DEGs through transcriptome analysis of larval S. esculenta within 24 h of Cu exposure. GO and KEGG functional enrichment analysis results indicated that Cu exposure may affect purine metabolism, protein digestion and absorption, cholesterol metabolism, and other metabolic processes in S. esculenta larvae. It is worth noting that in this study we explore metabolic mechanism of Cu-exposed S. esculenta larvae through the comprehensive analysis of protein–protein interaction network and KEGG enrichment analysis for the first time and find 20 identified key and hub genes such as CYP7A1, CYP3A11, and ABCA1. Based on their expression, we preliminarily speculate that Cu exposure may inhibit multiple metabolic processes and induce metabolic disorders. Our results lay a foundation for further understanding the metabolic mechanism of S. esculenta against heavy metals and provide theoretical help for S. esculenta artificial breeding.

The metabolic processes of organisms are very complex. Each process is crucial and affects the growth, development, and reproduction of organisms. Metabolism-related mechanisms in Octopus ocellatus behaviors have not been widely studied. Brood-care is a common behavior in most organisms, which can improve the survival rate and constitution of larvae. Octopus ocellatus carried out this behavior, but it was rarely noticed by researchers before. In our study, 3,486 differentially expressed genes (DEGs) were identified based on transcriptome analysis of O. ocellatus. We identify metabolism-related DEGs using GO and KEGG enrichment analyses. Then, we construct protein–protein interaction networks to search the functional relationships between metabolism-related DEGs. Finally, we identified 10 hub genes related to multiple gene functions or involved in multiple signal pathways and verified them using quantitative real-time polymerase chain reaction (qRT-PCR). Protein–protein interaction networks were first used to study the effects of brood-care behavior on metabolism in the process of growing of O. ocellatus larvae, and the results provide us valuable genetic resources for understanding the metabolic processes of invertebrate larvae. The data lay a foundation for further study the brood-care behavior and metabolic mechanisms of invertebrates.

Glycogen content is a quantitative trait, its phenotype differences are found between individual oysters due to genetic effects and environmental factors which were including food, water temperature, salinity, and so on. In this study, a full sibling family of Pacific oyster Crassostrea gigas showed different phenotypes with high and low glycogen content between South Huanghai Sea (Rizhao offshore area, RZ) and North Huanghai Sea (Kongtong Dao area, KTD), respectively. At the same time, the content of 11 glucogenic amino acids and 13 fatty acids were also significant differences between RZ and KTD. RNA-seq and small RNA-seq technologies were used for transcriptome sequencing and functional enrichment analysis of differentially expressed RNA were used by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. A total of 2,084 mRNAs, 1,080 long non-coding RNAs (lncRNAs), 34 circular RNAs (circRNAs), and 7 microRNAs (miRNAs) were differentially expressed. Based on these differentially expressed genes (DEGs), miRNA target interactions (lncRNA/circRNA–miRNA pairs and miRNA–mRNA pairs) were predicted using the miRanda software. The differentially expressed mRNAs in this network were mainly shown to be involved in calcium signaling pathway and insulin signaling pathway. These findings could help to speculate that environmental factors may be epigenetically regulated by non-coding RNA in C. gigas, thereby further affecting glycogen content.

Immune defense systems are indispensable for living organisms. Within an immune network, problems with any given link can impact the normal life activities of an organism. Amphioctopus fangsiao is a cephalopod that exists widely throughout the world’s oceans. Because of its nervous system and locomotive organs, it has become increasingly studied in recent years. Vibrio anguillarum is one of the most common pathogenic bacteria in aquaculture organisms. It is highly infectious and can infect almost all aquaculture organisms. V. anguillarum infection can cause many adverse biological phenomena, including tissue bleeding. Study the immune response after V. anguillarum infection would help us to understand the molecular mechanisms of immune response in aquaculture organisms. In this research, we infected the primary incubation A. fangsiao with V. anguillarum for 24 h. We analyzed gene expression in A. fangsiao larvae via transcriptome profiles at 0, 4, 12, and 24 h after hatching, and 1,385, 734, and 6,109 differentially expressed genes (DEGs) were identified at these three time points. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to identify immune-related DEGs. Protein–protein interaction networks were constructed to examine interactions between immune-related genes. Twenty hub genes involved in multiple KEGG signaling pathways or with multiple protein–protein interaction relationships were identified, and their differential expression verified by quantitative RT-PCR. We first studied V. anguillarum infection of A. fangsiao larvae by means of protein–protein interaction networks. The results provide valuable genetic resources for understanding immunity in molluscan larvae. These data serve as a theoretical basis for the artificial breeding of A. fangsiao.

A novel gill cell line from pearl gentian grouper (Epinephelus lanceolatus♂×Epinephelus fuscoguttatus♀, PGGG cell line) was established, its application in cadmium (Cd) toxicology was demonstrated in this study. Primary cultures and PGGG subcultures were carried out at 25 °C in Dulbecco’s Modified Eagle medium/F12 medium (1:1; pH 7.2) supplemented with 15% fetal bovine serum (FBS). Primary PGGG cells were spindle-shaped, proliferated into a confluent monolayer within two weeks and were continuously subcultured over passage 60. The growth of cells at passages 20, 40, and 60 was examined. Chromosome analysis revealed that the chromosomal number of normal PGGG cells was 48, but the number of cells with the normal chromosomes number decreased during the passaging process. Cadmium is one of the most toxic metals in aquatic systems and has been associated with multiple animal and human health problems. To interpret the cytotoxicity and related mechanisms of cadmium, PGGG cells were used as an in vitro model. After treatment with cadmium at concentrations ranging from 1 µM to 500 µM, PGGG cells demonstrated dose- and time-dependent cytotoxicity, manifested as morphological abnormalities and a viability decline. Further, it was found that the reactive oxygen species (ROS) and malondialdehyde (MDA) levels were elevated following cadmium exposure, and related genes involved in the antioxidant system, including those encoding catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and Kelch-like- ECH-associated protein 1 (Keap1), were regulated differently. In addition, PGGG cells treated with cadmium had the typical features associated with apoptosis, including phosphatidylserine (PS) externalization; upregulated expression of caspase-3, −8, and −9; and apoptotic body formation. In general, the PGGG cell line may serve as a useful tool for studying the toxic mechanisms of cadmium or other toxicants or for toxicity testing and environment monitoring.

The article presents a study which developed and described a set of EST-simple sequence repeats (SSRs) for the Pacific oyster, Crassotreat gigas. A total of 23,816 Crassotreat gigas ESTs from Genebank were downloaded and assembled. Sequence assembly produced 14,883 potential unigenes which contain contigs and singletons from all EST sequences. It was found that SSRs were developed successfully from EST in the Pacific oyster.

DNA barcoding is a promising tool for the rapid and unambiguous identification of species. Some arcoid species are particularly difficult to distinguish with traditional morphological identification owing to phenotypic variation and the existence of closely related taxa. Here, we apply DNA barcoding based on mitochondrial cytochrome c oxidase I gene (COI) to arcoid species collected from the coast along China. Combining morphology with molecular data indicates the 133 specimens of Arcoida could be assigned to 24 species. Because of the deep genetic divergence within Tegillarca granosa, there was an overlap between genetic variation within species and variation between species. Nevertheless, NJ and Bayesian trees showed that all species fell into reciprocally monophyletic clades with high bootstrap values. Our results evidence that the COI marker can efficiently identify species, correct mistakes caused by morphological identification and reveal genetic differentiation among populations within species. This study provides a clear example of the usefulness of barcoding for arcoid identification. Furthermore, it also lays a foundation for other biological and ecological studies of Arcoida. [ABSTRACT FROM AUTHOR]

DNA sequence data enable not only the inference of phylogenetic relationships but also provide an efficient method for species-level identifications under the terms DNA barcoding or DNA taxonomy. In this study, we have sequenced partial sequences of mitochondrial COI and 16S rRNA genes from 63 specimens of 8 species of Pectinidae to assess whether DNA barcodes can efficiently distinguish these species. Sequences from homologous regions of four other species of this family were gathered from GenBank. Comparisons of within and between species levels of sequence divergence showed that genetic variation between species exceeds variation within species. When using neighbour-joining clustering based on COI and 16S genes, all species fell into reciprocally monophyletic clades with high bootstrap values. These evidenced that these scallop species can be efficiently identified by DNA barcoding. Evolutionary relationships of Pectinidae were also examined using the two mitochondrial genes. The results are almost consistent with Waller's classification, which was proposed on the basis of shell microstructure and the morphological characteristics of juveniles. [ABSTRACT FROM AUTHOR]