Photodynamic therapy (PDT) is a clinically approved, minimally invasive therapeutic technique that can induce the regression of targeted lesions via generating excess cytotoxic reactive oxygen species. However, due to the limited penetration depth of visible excitation light and the intrinsic hypoxia microenvironment of solid tumors, the efficacy of PDT in the treatment of cancer, especially deep-seated or large tumors, is unsatisfactory. Herein, we developed an efficient in vivo PDT system based on a nanomaterial, dihydrolipoic acid coated gold nanocluster (AuNC@DHLA), that combined the advantages of large penetration depth in tissue, extremely high two-photon (TP) absorption cross section (σ 2 ∼ 10 6 GM), efficient ROS generation, a type I photochemical mechanism, and negligible in vivo toxicity. With AuNC@DHLA as the photosensitizer, highly efficient in vivo TP-PDT has been achieved.
A major hallmark of prion diseases is the cerebral amyloid accumulation of the pathogenic PrP(Sc), an abnormally misfolded, protease-resistant, and beta-sheet rich protein. PrP106-126 is the key domain responsible for the conformational conversion and aggregation of PrP. It shares important physicochemical characteristics with PrP(Sc) and presents similar neurotoxicity as PrP(Sc). By combination of fluorescence polarization, dye release assay and in situ time-lapse atomic force microscopy (AFM), we investigated the PrP106-126 amide interacting with the large unilamellar vesicles (LUVs) and the supported lipid bilayers (SLBs). The results suggest that the interactions involve a poration-mediated process: firstly, the peptide binding results in the formation of pores in the membranes, which penetrate only half of the membranes; subsequently, PrP106-126 amide undergoes the poration-mediated diffusion in the SLBs, represented by the formation and expansion of the flat high-rise domains (FHDs). The possible mechanisms of the interactions between PrP106-126 amide and lipid membranes are proposed based on our observations.
Porcine deltacoronavirus (PDCoV) has recently emerged as an enteric pathogen that can cause serious vomiting and diarrhea in suckling piglets. The first outbreak of PDCoV occurred in the United States in 2014 and was followed by reports of PDCoV in South Korea, China, Thailand, Lao People's Democratic Republic, and Vietnam, leading to economic losses for pig farms and posing a considerable threat to the swine industry worldwide. Our previous studies have shown that PDCoV encodes three accessory proteins, NS6, NS7, and NS7a, but the functions of these proteins in viral replication, pathogenesis, and immune regulation remain unclear. Here, we found that ectopic expression of accessory protein NS6 significantly inhibits Sendai virus-induced interferon beta (IFN-) production as well as the activation of transcription factors IRF3 and NF-B. Interestingly, NS6 does not impede the IFN- promoter activation mediated via key molecules in the RIG-I-like receptor (RLR) signaling pathway, specifically RIG-I, MDA5, and their downstream molecules MAVS, TBK1, IKK, and IRF3. Further analyses revealed that NS6 is not an RNA-binding protein; however, it interacts with RIG-I/MDA5. This interaction attenuates the binding of double-stranded RNA by RIG-I/MDA5, resulting in the reduction of RLR-mediated IFN- production. Taken together, our results demonstrate that ectopic expression of NS6 antagonizes IFN- production by interfering with the binding of RIG-I/MDA5 to double-stranded RNA, revealing a new strategy employed by PDCoV accessory proteins to counteract the host innate antiviral immune response.IMPORTANCE Coronavirus accessory proteins are species specific, and they perform multiple functions in viral pathogenicity and immunity, such as acting as IFN antagonists and cell death inducers. Our previous studies have shown that PDCoV encodes three accessory proteins. Here, we demonstrated for the first time that PDCoV accessory protein NS6 antagonizes IFN- production by interacting with RIG-I and MDA5 to impede their association with double-stranded RNA. This is an efficient strategy of antagonizing type I IFN production by disrupting the binding of host pattern recognition receptors (PRRs) and pathogen-associated molecular patterns (PAMPs). These findings deepen our understanding of the function of accessory protein NS6, and they may direct us toward novel therapeutic targets and lead to the development of more effective vaccines against PDCoV infection.
Algal-bloom control is an important issue for water environment protection as it induces several negative impacts on the lives of aquatic organisms, aquaculture, landscaping, and human health. The development of an environment-friendly, cost-effective, and convenient alternative for controlling algal bloom has gained much concern. Using the allelopathy of aquatic macrophytes as a novel and safe method for algal-bloom control is a promising alternative. This paper reviews the development and potential application about allelopathy of aquatic plants on algae, including the allelopathic research history, the potential research problems, the research methodology, and the reported aquatic macrophytes and their inhibitory allelochemicals. Potential modes of inhibition action of allelochemicals on algae, possible ways for application, and future development directions of research on algal-bloom control by aquatic macrophytes were also presented.
In recent years, silica coating has been extensively investigated to fabricate the biocompatible interface of quantum dots (QDs) for biomedical applications. We here describe a facile and efficient method of synthesizing high-quality silica-coated CdSeS QDs (CdSeS QD/SiO(2)), where an immediate photoluminescence-favorable microenvironment is first created by assembling amphiphilic molecules around the CdSeS core, and a thin silica shell is further introduced to protect this hydrophobic interlayer. The prepared CdSeS QD/SiO(2) exhibits excellent properties such as good water solubility, low cytotoxicity, and high quantum yield (QY, up to 0.49) as well as the resistance of photobleaching in aqueous solution. Also, the CdSeS QD/SiO(2) nanoparticles homogeneously comprise single CdSeS cores and hold a comparatively small size up to about 11 nm in diameter. Particularly, this method leads to a significant increase in QY as compared to the uncoated CdSeS QDs ( approximately 109% of the initial QY), though only thin silica shells formed in the CdSeS QD/SiO(2) structure. By coupling with folic acids, the CdSeS QD/SiO(2) conjugates were successfully used for tumor cell labeling. Our results demonstrated a robust hydrophobic QDs-based approach for preparing highly photoluminescent, biocompatible QD/SiO(2) through creation of a stable hydrophobic interlayer surrounding the QD cores, which could be also suitable for silica coating of other kinds of hydrophobic nanoparticles.
Porcine deltacoronavirus (PDCoV) is an emerging swine enteric coronavirus. Bioinformatics predicts that PDCoV encodes two accessory proteins (NS6 and NS7), the species-specific proteins for coronavirus. In this study, four mAbs against the predicted NS7 were prepared by using the purified recombinant NS7 protein. Indirect immunofluorescence assay demonstrated that all mAbs recognized cells transfected with an NS7 expression construct or infected with PDCoV. Western blot showed that NS7-specific mAbs recognized an additional protein band of about 12 kDa from PDCoV-infected cell lysates but not from cells with the ectopic expression of NS7. Detailed analysis suggested that this additional protein band represented a novel accessory protein, termed NS7a, a 100 amino acid polypeptide identical to the 3' end of NS7. Moreover, NS7a is encoded by a separate subgenomic mRNA with a non-canonical transcription regulatory sequence. In summary, our results identified a third accessory protein encoded by PDCoV, which will enhance our understanding of PDCoV.
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