Molecular cloning and characterization of Pif gene from pearl mussel, Hyriopsis cumingii, and the gene expression analysis during pearl formation

Diversification of von Willebrand Factor A and Chitin-Binding Domains in Pif/BMSPs Among Mollusks

Pif is a shell matrix protein (SMP) identified in the nacreous layer of Pinctada fucata (Pfu) comprised two proteins, Pif97 and Pif 80. Pif97 contains a von Willebrand factor A (VWA) and chitin-binding domains, whereas Pif80 can bind calcium carbonate crystals. The VWA domain is conserved in the SMPs of various mollusk species; however, their phylogenetic relationship remains obscure. Furthermore, although the VWA domain participates in protein-protein interactions, its role in shell formation has not been established. Accordingly, in the current study, we investigate the phylogenetic relationship between PfuPif and other VWA domain-containing proteins in major mollusk species. The shell-related proteins containing VWA domains formed a large clade (the Pif/BMSP family) and were classified into eight subfamilies with unique sequential features, expression patterns, and taxa diversity. Furthermore, a pull-down assay using recombinant proteins containing the VWA domain of PfuPif 97 revealed that the VWA domain interacts with five nacreous layer-related SMPs of P. fucata, including Pif 80 and nacrein. Collectively, these results suggest that the VWA domain is important in the formation of organic complexes and participates in shell mineralisation.

The Application of Pearls in Traditional Medicine of China and Their Chemical Constituents, Pharmacology, Toxicology, and Clinical Research

Although pearls are well known by most people, their medicinal value has not been popularized. This article collates the medicinal history of pearls over 2,000 years in China, including the application of pearls in the traditional medicine of China and their various preparations, as well as the progress of their chemical constituents, pharmacology, toxicology, and clinical research. Pearls from three different sources are used as medical materiel by 9 nationalities and 251 prescription preparations in China. In addition, pearls contain various inorganic constituents, such as calcium carbonate, trace elements, and water, and organic constituents, such as amino acids. In terms of pharmacology, pearls have many effects such as calming, improving cognitive ability, being anti-epileptic, promoting bone growth and regeneration, promoting the proliferation and migration of human microvascular endothelial cells, protecting the heart, anti-hemolysis, and anti-oxidation. In terms of toxicology, pearls are safe to take for a long time without exerting obvious adverse reactions. In terms of clinical application, pearls have been used to treat many diseases and conditions, such as convulsions, epilepsy, palpitations, eye diseases, ulcer diseases, skin diseases, or skin lesions. This article provides a reference for the application and research of pearls in the future.

Molecular characterization of the nitric oxide synthase gene and its immunomodulation of nitric oxide production in the triangle shell mussel (Hyriopsis cumingii)

Nitric oxide synthase (NOS) is a critical enzyme that catalyzes nitric oxide biosynthesis and orchestrates various immunological responses mediated by nitric oxide (NO) in host animals. In this study, the NOS gene was identified in the triangle shell mussel (Hyriopsis cumingii) (HcNOS). HcNOS was highly conserved in the characteristic gene structures of NOS. Phylogenetic analysis suggested that HcNOS was a typical invertebrate NOS. Further gene expression analysis, NOS activity assays and nitric oxide content measurements demonstrated the inducibility of HcNOS in responses to lipopolysaccharide (LPS) challenge and during tissue transplantation. Of note, mantle grafting induced a prolonged HcNOS/NO response, suggesting that through the HcNOS/NO system, multiple immunomodulators may play decisive roles in tissue grafting in triangle shell mussels. Thus, HcNOS appears to be a crucial player in responding to both bacterial infection and tissue transplantation.

Apigetrin ameliorates streptozotocin-induced pancreatic β-cell damages via attenuating endoplasmic reticulum stress

The pathogenesis of diabetes is associated with dysfunction of pancreatic β-cells. To ameliorate the β-cell dysfunction, it has propelled great interest to search pharmacological agents from natural plants. This study explored the protective effect of apigetrin, a flavonoid present in natural plants, against streptozotocin (STZ)-induced cell damages in RINm5F cells and the potential mechanisms. Apigetrin was found to inhibit the elevation of intracellular reactive oxygen species levels, restore the impairment of antioxidant enzymes, and recover the disruption of redox homeostasis in the STZ-treated pancreatic β-cells. Moreover, treatment of apigetrin significantly suppressed the STZ-induced apoptosis in the analysis of apoptotic sub-G₁ population and the protein expressions of cleaved poly(ADP-ribose) polymerase and caspase-3. Furthermore, apigetrin attenuated STZ-induced endoplasmic reticulum (ER) stress, indicated by the reduction of ER stress biomarkers, including overloading of mitochondrial calcium, increase in glucose-regulated protein 78, phosphorylation of protein kinase RNA-like ER kinase and its downstream eukaryotic initiation factor 2α, cleavage of activating transcription factor 6 and caspase-12, up-regulation of CCAAT/enhancer binding protein homologous protein, and induction of spliced X-box binding protein 1. Additionally, pretreatment with 4-phenylbutyric acid, a classic ER stress inhibitor, augmented these beneficial effects of apigetrin. In conclusion, these results demonstrated that apigetrin could improve the STZ-induced pancreatic β-cell damages via mitigation of oxidative stress and ER stress and supported the application of apigetrin to developing the novel therapeutics of diabetes.

Molecular cloning of complement component C3 gene from pearl mussel, Hyriopsis cumingii and analysis of the gene expression in response to tissue transplantation

Complement component C3 is well recognized as the central mediator of complement system, whose activation is responsible for the immune surveillance and elimination of non-self-antigens. In this study, C3 gene (HcC3) from a pearl making mussel, Hyriopsis cumingii, was successfully identified. The putative HcC3 possessed the canonical domains and highly conserved functional residues of C3 family members. In phylogenetic analysis, HcC3 was also clustered into C3 subfamily and separated from α2 macroglobulin clade. HcC3 gene was constitutively expressed in a wide range of tissues of pearl mussels, among which the immune-related tissues like hemocytes got highest expression. After allograft surgery of mantle tissues for aquaculture pearl production, the gene expression of HcC3 exhibited a rapid upregulation on day 1, dropped back on day 3, peaked the value on day 7, and restored to the level similar to control samples on day 14 after mantle allograft. The biphasic expression within the two weeks post the surgery suggests the important roles for HcC3 in alloimmune responses and an intricate complement activation mechanism in mollusks during tissue allograft.