Image_2_Increased histone H3 acetylation inhibit the inflammatory response and activate the serum immunity of Pearl oyster Pinctada fucata martensii.tif

To produce cultured pearls, a mantle graft with a nucleus is transplanted into a host pearl oyster, this process is called “transplantation”. The immune response of pearl oyster after transplantation is a major factor that leads to nucleus rejection and death. Butyrate is a histone deacetylase (HDAC) inhibitor which can inhibit the deacetylation process of histones and effectively reduce the inflammatory response. To clarify the function of histone acetylation in immune response after transplantation, butyrate (10 mmol/L) was used for the treatment of pearl oysters before transplantation. Results showed that the proportion of histone H3 acetylation of the hemocytes was significantly increased after butyrate treatment before transplantation (BH group) compared with the control group at 6–24 h. Transcriptome analysis showed that butyrate treatment activated the “lysosome”, inhibited cell migration and cell proliferation at 6 and 12 h, respectively, and activated the intracellular immune recognition response of pearl oyster at 24 h after transplantation. The apoptosis detection revealed no significant difference in the proportion of apoptotic cells between the control and BH group. Moreover, butyrate treatment increased the activity of some immune-related enzymes in the serum of pearl oyster after transplantation.</p

Image_1_Increased histone H3 acetylation inhibit the inflammatory response and activate the serum immunity of Pearl oyster Pinctada fucata martensii.tif

To produce cultured pearls, a mantle graft with a nucleus is transplanted into a host pearl oyster, this process is called “transplantation”. The immune response of pearl oyster after transplantation is a major factor that leads to nucleus rejection and death. Butyrate is a histone deacetylase (HDAC) inhibitor which can inhibit the deacetylation process of histones and effectively reduce the inflammatory response. To clarify the function of histone acetylation in immune response after transplantation, butyrate (10 mmol/L) was used for the treatment of pearl oysters before transplantation. Results showed that the proportion of histone H3 acetylation of the hemocytes was significantly increased after butyrate treatment before transplantation (BH group) compared with the control group at 6–24 h. Transcriptome analysis showed that butyrate treatment activated the “lysosome”, inhibited cell migration and cell proliferation at 6 and 12 h, respectively, and activated the intracellular immune recognition response of pearl oyster at 24 h after transplantation. The apoptosis detection revealed no significant difference in the proportion of apoptotic cells between the control and BH group. Moreover, butyrate treatment increased the activity of some immune-related enzymes in the serum of pearl oyster after transplantation.</p

Table_1_Lipidomic insights into the immune response and pearl formation in transplanted pearl oyster Pinctada fucata martensii.docx

During pearl culture, the excess immune responses may induce nucleus rejection and death of pearl oysters after transplantation. To better understand the immune response and pearl formation, lipidomic analysis was applied to investigate changes in the serum lipid profile of pearl oyster Pinctada fucata martensii following transplantation. In total, 296 lipid species were identified by absolute quantitation. During wound healing, the content of TG and DG initially increased and then decreased after 3 days of transplantation with no significant differences, while the level of C22:6 decreased significantly on days 1 and 3. In the early stages of transplantation, sphingosine was upregulated, whereas PC and PUFAs were downregulated in transplanted pearl oyster. PI was upregulated during pearl sac development stages. GP and LC-PUFA levels were upregulated during pearl formation stage. In order to identify enriched metabolic pathways, pathway enrichment analysis was conducted. Five metabolic pathways were found significantly enriched, namely glycosylphosphatidylinositol-anchor biosynthesis, glycerophospholipid metabolism, alpha-linolenic acid metabolism, linoleic acid metabolism and arachidonic acid metabolism. Herein, results suggested that the lipids involved in immune response, pearl sac maturation, and pearl formation in the host pearl oyster after transplantation, which might lead to an improvement in the survival rate and pearl quality of transplanted pearl oyster.</p

DataSheet_1_Lipidomic insights into the immune response and pearl formation in transplanted pearl oyster Pinctada fucata martensii.docx

During pearl culture, the excess immune responses may induce nucleus rejection and death of pearl oysters after transplantation. To better understand the immune response and pearl formation, lipidomic analysis was applied to investigate changes in the serum lipid profile of pearl oyster Pinctada fucata martensii following transplantation. In total, 296 lipid species were identified by absolute quantitation. During wound healing, the content of TG and DG initially increased and then decreased after 3 days of transplantation with no significant differences, while the level of C22:6 decreased significantly on days 1 and 3. In the early stages of transplantation, sphingosine was upregulated, whereas PC and PUFAs were downregulated in transplanted pearl oyster. PI was upregulated during pearl sac development stages. GP and LC-PUFA levels were upregulated during pearl formation stage. In order to identify enriched metabolic pathways, pathway enrichment analysis was conducted. Five metabolic pathways were found significantly enriched, namely glycosylphosphatidylinositol-anchor biosynthesis, glycerophospholipid metabolism, alpha-linolenic acid metabolism, linoleic acid metabolism and arachidonic acid metabolism. Herein, results suggested that the lipids involved in immune response, pearl sac maturation, and pearl formation in the host pearl oyster after transplantation, which might lead to an improvement in the survival rate and pearl quality of transplanted pearl oyster.</p

Table_1_Long non-coding RNA LncMPEG1 responds to multiple environmental stressors by affecting biomineralization in pearl oyster Pinctada fucata martensii.docx

Marine environmental change directly affects bivalve growth and survival. Exoskeleton formation, the main energy dissipation in the physiological metabolism, typically reflects the body growth of the bivalve. However, how bivalves regulate the biomineralization of the exoskeleton under environmental stressors is not yet clear. Long non-coding RNA regulates various life processes through complex mechanisms in vertebrates and invertebrates. In this research, we cloned the complete sequence of a mantle-specific expressed long non-coding RNA (designated as LncMPEG1) from a pearl oyster, Pinctada fucata martensii. A quantitative real-time PCR analysis showed that LncMPEG1 expression was significantly high in early umbo larvae and juveniles, which would be the critical periods of shell development. LncMPEG1 was identified in the outer epithelium of the middle fold from the mantle edge, mantle pallial, and mantle center by using in situ hybridization. Additionally, the expression of LncMPEG1 was stimulated by shell damage, alien invasion, heat and cold temperature stress, and hypoxia stress. In the mantle, a decreased in LncMPEG1 expression was detected by RNA interference, which can cause the irregular growth of crystals on the inner surface of the prismatic layer and nacre in the shells. Therefore, we propose that LncMPEG1 could be a key regulator in biomineralization and responds to environmental stress in the mantle .</p