Identification and characterization of phosphoproteins in the striated and smooth adductor muscles of Yesso scallop Patinopecten yessoensis

Controlling the quality of Patinopecten yessoensis from the perspective of the ultrasound and ferulic acid influences

In this study, the effects of ultrasound combined with ferulic acid (FA) on the quality of the Yesso scallop (Patinopecten yessoensis) adductor muscles (SAM) during refrigerated storage were investigated. The results demonstrated that the combined treatment with 350 W ultrasound and FA (UFA) significantly delayed enzyme activities and microbial growth in SAM tissues compared to FA treatment alone. After 6 days of cold storage, samples treated with UFA exhibited higher hardness (2850 g), lower thiobarbituric acid reactive substances (TBARS = 9.35 MDA mg/g SAM), and lower total volatile basic nitrogen (TVB-N = 19.75 mg/100 g SAM) values compared to control and FA-treated samples. Consequently, UFA treatment prolonged the shelf life of SAM by 3 days during storage at 4°C. Based on scanning electron microscopy and low-field nuclear magnetic resonance data, these findings are attributed to UFA treatment not only reducing the degradation of SAM tissue network structure but also minimizing water loss. PRACTICAL APPLICATION: Scallop adductor muscle (SAM) is commonly considered a delicacy owing to its unique mouthfeel and delicious taste. However, owing to its high moisture content and high levels of various nutrients, SAM has a short shelf life. In this work, a combination of ultrasound with ferulic acid (UFA) has been found to have effective preservation effects on SAM during refrigerated storage. Our study findings pave the way for a potential approach to maintain scallop quality during processing and storage. Moreover, our study also provides some theoretical basis for using and promoting these technologies in aquatic products.

Phosphoproteomics changes due to allograft-induced stress responses of Pinctada fucata martensii

Protein phosphorylation modifications are post-translational modifications (PTMs) that play important roles in signal transduction and immune regulation. Implanting a spherical nucleus into a recipient shellfish is critical in marine pearl aquaculture. Protein phosphorylation may be important in the immune responses of Pinctada fucata martensii after nucleus implantation, but their involvement in regulation remains unclear. Here, phosphoproteomics of P. f. martensii gill tissues was conducted 12 h after nuclear implantation using label-free data-independent acquisition (DIA) with LC-MS/MS. Among the 4024 phosphorylated peptides with quantitative information, 181 were up-regulated and 148 were down-regulated. Functional enrichment analysis of these differentially expressed phosphorylated proteins (DEPPs) revealed significant enrichment in functions related to membrane trafficking, exosomes, cytoskeleton, and signal transduction mechanisms. Further, 16 conserved motifs were identified among the DEPPs, including the RSphP, SphP, RSphA, RSphE, PTphP, and ATphP motifs that were significantly conserved, and which may be related to specific kinase recognition. Parallel response monitoring (PRM) analysis validated the abundances of 12 DEPPs from the proteomics, indicating that the phosphoproteomics analyses were robust. 12 DEPPs were selected from the proteomics results through Quantitative real-time PCR (qPCR) technology, and verification analysis was conducted at the gene level. The study suggests that kinases such as MAPKs, Akt, and CK2 may regulate the phosphorylation of related proteins following nuclear implantation. Furthermore, the important signaling pathways of Rap 1, IL-17A, and NF-κB, which are influenced by phosphorylated or dephosphorylated proteins, are found to be involved in this response. Overall, this study revealed the protein phosphorylation responses after nucleus implantation in P. f. martensii, helping to elucidate the characteristics and mechanisms of immune regulation responses in P. f. martensii, in addition to promoting a further understanding of protein phosphorylation modification functions in P. f. martensii.

MicroRNA expression signature in the striated and smooth adductor muscles of Yesso scallop Patinopecten yessoensis

Increasing evidences point to the potential role of microRNAs (miRNAs) in muscle growth and development in animals. However, knowledge on the identity of miRNAs and their targets in molluscs remains largely unknown. Scallops have one large adductor muscle, composed of fast (striated) and slow (smooth) muscle types, which display great differences in muscle fibers, meat quality, cell types and molecular components. In the present study, we performed a comprehensive investigation of miRNA transcriptomes in fast and slow adductor muscles of Yesso scallop Patinopecten yessoensis. As a result, 47 differentially expressed miRNAs representing ten miRNA families were identified between the striated and smooth adductor muscles. The KEGG enrichment analysis of their target genes were mainly associated with amino acid metabolism, energy metabolism and glycan biosynthesis. The target genes of miR-133 and miR-71 were validated by the dual-luciferase reporter assays and miRNA antagomir treatment in vivo. The identification and functional validation of these different miRNAs in scallops will greatly help our understanding of miRNA regulatory mechanism that achieves the unique muscle phenotypes in scallops. The present findings provide the direct evidences for muscle-specific miRNAs involved in muscle growth and differentiation in molluscs.

Molecular Characterization and Expression Pattern of Paramyosin in Larvae and Adults of Yesso Scallop

Simple Summary

Paramyosin is an important myofibrillar protein in smooth muscle in molluscs that is not present in vertebrate muscles. This study characterized its sequence feature and expression patterns in Yesso scallop Patinopecten yessoensis and revealed the unique phosphorylation sites in scallops. The mRNA and protein expression of paramyosin was mainly found in foot and smooth adductor muscle. At late larval stages, strong paramyosin mRNA signals were detected in the symmetric positions of anterior and posterior adductor muscles. The present findings support that paramyosin may serve as the most important component of smooth muscle assembly during muscle development and catch regulation in scallops.

Abstract

Paramyosin is an important myofibrillar protein in molluscan smooth muscle. The full-length cDNA encoding paramyosin has been identified from Yesso scallop Patinopecten yessoensis. The length of paramyosin molecule has been found to be 3715 bp, which contains an open reading frame (ORF) of 2805 bp for 934 amino acid residues. Characterization of P. yessoensis paramyosin reveals the typical structural feature of coiled-coil protein, including six α-helix (α1-α6) and one coil (η) structures. Multiple phosphorylation sites have been predicted at the N-terminus of paramyosin, representing the unique phosphorylation sites in scallops. The highest levels of mRNA and protein expression of paramyosin have been found in foot and the smooth adductor muscle. According to whole-mount in situ hybridization (WISH), strong paramyosin mRNA signals were detected in the symmetric positions of anterior and posterior adductor muscles at late larval stages. These findings support that paramyosin may serve as the most important components for myogenesis and catch regulation in scallops. The present findings will not only help uncover the potential function of myofibrillar proteins in molluscs but also provide molecular evidence to infer evolutionary relationships among invertebrates.