The primary influencer of aquaculture quality in Amphioctopus fangsiao is pathogen infection. Both lipopolysaccharides (LPS) and polyinosinic:polycytidylic acid (Poly I:C) are recognized by the pattern recognition receptor (PRR) within immune cells, a system that frequently serves to emulate pathogen invasion. Hemolymph, which functions as a transport mechanism for immune cells, offers vital transcriptome information when A. fangsiao is exposed to pathogens, thereby contributing to our comprehension of the species’ immune biological mechanisms. In this study, we conducted analyses of transcript profiles under the influence of LPS and Poly I:C within a 24 h period. Concurrently, we developed a Weighted Gene Co-expression Network Analysis (WGCNA) to identify key modules and genes. Further, we carried out Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses to investigate the primary modular functions. Co-expression network analyses unveiled a series of immune response processes following pathogen stress, identifying several key modules and hub genes, including PKMYT1 and NAMPT. The invaluable genetic resources provided by our results aid our understanding of the immune response in A. fangsiao hemolymph and will further our exploration of the molecular mechanisms of pathogen infection in mollusks.

Cu and Cd, as common heavy metals occurring in the oceans, can induce oxidative stress and toxic responses in marine organisms. Important economic cephalopods inhabit the eastern coastal areas of China, and exposure to Cu and Cd poses a threat to their normal physiological activities, resulting in serious inhibition of their growth. However, the underlying toxicological mechanisms affecting these cephalopods’ larval stages remain to be elucidated. Here, indicators of oxidative stress and transcriptomics were employed to analyze the toxicological mechanisms of S. esculenta larvae exposed to Cd and Cu. GO and KEGG analysis results indicated that material transport, cellular processes, DNA replication, and other processes were inhibited. A comprehensive analysis of a protein–protein interaction network and KEGG pathways was used to explore the mechanism underlying the toxicity of co-exposure to Cu and Cd toward S. esculenta larvae. We found that Cu and Cd induce significant damage and oxidative stress. The results showed that among 20 identified key genes, ITGA4, LAMA1, and LAMC1, which are involved in the adhesion and connection between cells and the extracellular matrix; COL6A1, COL6A3, COL6A4, and COL6A6, which maintain the integrity of the extracellular matrix; and ABCA1, ABCC5, and ABCC7, which regulate the transmembrane transport of Cu and Cd were involved in the mechanism of toxicity. We suggest that co-exposure to the metals primarily inhibits the connection and adhesion between the cells of the larvae and disrupts the structure and function of the extracellular matrix. The results provide a foundation for understanding the toxicological mechanism of S. esculenta and should be of benefit to artificial breeding programs.

As the quality of life improves, there is an increasing demand for nutrition-rich marine organisms like fish, shellfish, and cephalopods. To address this, artificial cultivation of these organisms is being explored along with ongoing research on their growth and development. A case in point is Amphioctopus fangsiao, a highly valued cephalopod known for its tasty meat, nutrient richness, and rapid growth rate. Despite its significance, there is a dearth of studies on the A. fangsiao growth mechanism, particularly of its larvae. In this study, we collected A. fangsiao larvae at 0, 4, 12, and 24 h post-hatching and conducted transcriptome profiling. Our analysis identified 4467, 5099, and 4181 differentially expressed genes (DEGs) at respective intervals, compared to the 0 h sample. We further analyzed the expression trends of these DEGs, noting a predominant trend of continuous upregulation. Functional exploration of this trend entailed GO and KEGG functional enrichment along with protein–protein interaction network analyses. We identified GLDC, DUSP14, DPF2, GNAI1, and ZNF271 as core genes, based on their high upregulation rate, implicated in larval growth and development. Similarly, CLTC, MEF2A, PPP1CB, PPP1R12A, and TJP1, marked by high protein interaction numbers, were identified as hub genes and the gene expression levels identified via RNA-seq analysis were validated through qRT-PCR. By analyzing the functions of key and core genes, we found that the ability of A. fangsiao larvae to metabolize carbohydrates, lipids, and other energy substances during early growth may significantly improve with the growth of the larvae. At the same time, muscle related cells in A. fangsiao larvae may develop rapidly, promoting the growth and development of larvae. Our findings provide preliminary insights into the growth and developmental mechanism of A. fangsiao, setting the stage for more comprehensive understanding and broader research into cephalopod growth and development mechanisms.