Shantou University

As multiple imaging modalities cannot reliably diagnose cardiac tumors, the molecular approach offers alternative ways to detect rare ones. One such molecular approach is CRISPR-based diagnostics (CRISPR-Dx). CRISPR-Dx enables visual readout, portable diagnostics, and rapid and multiplex detection of nucleic acids such as microRNA (miRNA). Dysregulation of miRNA expressions has been associated with cardiac tumors such as atrial myxoma and angiosarcoma. Diverse CRISPR-Dx systems have been developed to detect miRNA in recent years. These CRISPR-Dx systems are generally classified into four classes, depending on the Cas proteins used (Cas9, Cas12, Cas13, or Cas12f). CRISPR/Cas systems are integrated with various isothermal amplifications to detect low-abundance miRNAs. Amplification-free CRISPR-Dx systems have also been recently developed to detect miRNA directly. Herein, we critically discuss the advances, pitfalls, and future perspectives for these CRISPR-Dx systems in detecting miRNA, focusing on the diagnosis and prognosis of cardiac tumors.

The complex and diverse sexual reproduction patterns and multiple sex types of mollusks make it important to elucidate their sex mechanisms. Recent studies have demonstrated the crucial roles of Dmrt, STAT, and Sox genes in animal sex determination/differentiation. However, the comprehensive comparison of these genes in different bivalves is limited. In this study, 33 bivalves were analyzed to investigate the sequence characteristics, phylogenetic relationships, and expression profiles of these genes. Total of 112 Dmrt genes, 88 STAT genes and 229 Sox genes were identified in 33 bivalves. Phylogenetic analysis grouped the Dmrt, STAT, and Sox genes into 4, 3, and 7 groups, respectively. By comparing gene family number and sequence differences, we observed expansion and contraction in the Dmrt and STAT family genes, as well as sequence variations in Dmrt-01 and SoxH among different bivalves, suggesting their molecular adaptations to diverse sexual mechanisms. Expression profiles of these genes in noble scallop Chlamys nobilis revealed that CnDmrt-01 and CnSox-07 (SoxH) is predominantly expressed in testis, suggesting their male-specific role in gonad development and maturation. A higher expression level of CnSox-01/03 (Sox-B1/C) in ovary suggest their essential role in ovary development. These genes also showed significantly higher expression level during sex reversal, suggesting their crucial roles in this process. Additionally, transcriptome data from other bivalves further support that the sexual expression patterns of Dmrt-01 and Sox-B1/C/H are conserved across most bivalves. The results of this study will provide insights into these sex-related genes and useful information to better understand mechanisms of gonad development and sex reversal in mollusc.

Mollusks are the second Phylum in the Kingdom Animalia, which provide not only high-quality protein but also serves as a viewing function for humans due to the polymorphism in shell colors. However, the mechanisms of the differences in shell colors, especially on scallops, have rarely been studied. In this study, the shell and mantle of two different shell colors (golden and brown) of the noble scallops Chlamys nobilis were analyzed, including their microstructure, pigment content, and gene expression. The results showed that the golden scallop shell is golden from the outside to the inside, while the prismatic and nacreous layers in the brown scallop are lighter in color than the periostracum. Unlike the golden scallop, there was a layer of melanin vesicles at the edge of the brown scallop mantle. The total carotenoids content (TCC) in the mantle and shell of the golden scallop was significantly higher than that of the brown scallops (P < 0.05), but the melanin content was significantly lower than that of the brown scallop (P < 0.05). Candidate genes such as BCDO1, CYP5A, CYP2J, CYBA, EP300, and GNAO were screened from the differentially expressed genes (DEGs), and their differential expression may explain the differences in melanin and carotenoid content between the golden and brown scallops. These findings will help to understand the color polymorphism of noble scallops and provide a basis for further research on the inheritance of noble scallops.