Mineral acid-triggered multicolor room-temperature phosphorescence nanoprobes for time-resolved bioimaging.

We present a facile strategy to achieve color-tunability room-temperature phosphorescence (RTP) nanoprobes by doping mineral acids (i.e., boric acid and phosphoric acid) in an organic silicon scaffold through a cross-linking process. Such RTP nanoprobes exhibit inherent tunable phosphorescence (from 420-650 nm) with long lifetime (emission lasting for ∼5-15 s, RTP lifetime: ∼0.53-2.11 s) and high quantum yields (∼13.1-43.0%). Therefore, the as-prepared nanoprobes enable multiple imaging in live cells with a high signal-to-background ratio value of ∼52.

Analysis of protein kinase C (HcPKC) gene expression and single-nucleotide polymorphisms related to inner shell color traits in Hyriopsis cumingii.

BACKGROUND: Protein kinase C (PKC) is a multifunctional serine and PKC can phosphorylate serine residues in the cytoplasmic domain of tyrosinase, thereby regulating the activity of tyrosinase. Activated PKC is bound to the melanosome membrane, and unactivated PKC is free in the cytoplasm of melanocytes. In this study, we study the role of PKC gene in the melanin synthesis pathway and its effect on the color of the nacre of H. cumingii. RESULTS: In this study, a HcPKC gene in H. cumingii was cloned and its effects on melanin synthesis and nacre color were studied. HcPKC was expressed in both purple and white mussels, and the level of mRNA expression was higher in the purple mussels than in white mussels. Strong and specific mRNA signals were detected in the dorsal epithelial cells of the mantle pallial layer, indicating that HcPKC may be involved in nacre formation. After SNP association with inner shell color related traits, according to the principle that 0.25 < PIC < 0.5 is medium polymorphism and PIC < 0.25 is low polymorphism, the A + 332G site on the HcPKC gene was a site of moderate polymorphism, and the other four sites were low polymorphism sex sites. There was strong linkage disequilibrium among the five loci. A haplotype was constructed and it was found that the frequency of T1 (AGGAA)in the white population was significantly higher than that in the purple population (P < 0.05). CONCLUSION: The study found that HcPKC of H. cumingii can be used as a candidate gene related to inner shell color, and some of the SNP sites can be used for molecular-assisted breeding in the spinnaker mussel, providing a reference for cultivating high-quality freshwater pearls.

Cloning of a HcCreb gene and analysis of its effects on nacre color and melanin synthesis in Hyriopsis cumingii.

Creb (Cyclic AMP response element binding protein) is a nuclear regulatory factor that regulates transcription through autophosphorylation. In melanocytes, cAMP's corresponding elements bind to the Creb protein to autophosphorylation and activate MITF (Microphthalmia-associated transcription factor). MITF stimulates Tyrosine(tyr) to induce melanocytes to differentiate into eumelanin and pheomelanin. In this study, a HcCreb gene in Hyriopsis cumingii was cloned and its effects on melanin synthesis and nacre color were studied. HcCreb was expressed in both purple and white mussels, and there was a significant difference in expression between adductor muscle (p<0.01) and mantle tissue (p<0.05). Other tissues did not show significant differences (except for gill tissue), and in general, the level of mRNA expression was higher in purple mussels than in white mussels. In both white and purple mussels expression levels in gill tissue was the highest, followed by the mantle. Strong and specific mRNA signals were detected in the dorsal epithelial cells of the mantle pallial layer, indicating that HcCreb may be involved in nacre formation. After arbutin treatment, the expression of HcCreb decreased significantly. By further testing the changes in mantle melanin content it was found that the melanin content after arbutin treatment decreased significantly compared to the control group (p<0.05). It is speculated that the HcCreb gene plays a role in the process of melanin synthesis and nacre color formation in H. cumingii.

miR-4504 is involved in nacre color formation in Hyriopsis cumingii.

Pearl color is affected by the nacre color of shells in Hyriopsis cumingii, and is the primary indicator of its value. MicroRNAs (miRNAs) are endogenous small non-coding RNAs that play important roles in many biological processes, including pigmentation. In this study, we used a luciferase reporter assay to identify that miR-4504 can interact with the 3'-untranslated region of the MITF gene in H. cumingii (HcMitf). After injecting mussels with the miR-4504 antagomir, the expression of miR-4504 was inhibited. Upon miR-4505 silencing, the expression of HcMitf and its downstream gene, HcTyr, were simultaneously increased. Tyrosinase activity and melanin content were also increased. The collective findings indicated that miR-4504 was involved in melanin synthesis in H. cumingii. These findings also improve our understanding of the molecular mechanisms of nacre color formation in H. cumingii.

A mechanistic study of silica-etching by hot water.

The etching of colloidal silica by hot water provides a green chemistry method for the preparation of mesoporous silica. Nevertheless, the reaction mechanism of this etching process has not been elucidated and its reproducibility is often questionable, which has hindered its widespread application in the preparation of mesoporous silica materials. Herein, we present a systematic study on the hot-water etching of sol-gel derived silica shells coated on α-Fe2O3 particles. Transmission electron microscopy and infrared spectroscopy studies provide substantial evidence that colloidal silica with low hydrolysis and condensation degrees (or aging degrees) is preferentially etched by hot water. More importantly, we show that the aging degree of silica shells, which determines the etching rate, can be precisely tuned by controlling the sol-gel preparation time and the storage time in room-temperature water prior to hot-water etching. These results provide novel insights into the physicochemical properties of sol-gel derived colloidal silica and the mechanistic understanding of the reaction kinetics of silica etching by hot water.