Fluorescent ferritin nanoparticles and application to the aptamer sensor

We synthesized fluorescent ferritin nanoparticles (FFNPs) through bacterial expression of the hybrid gene consisting of human ferritin heavy chain (hFTN-H), spacer (glycine-rich peptide), and enhanced green (or red) fluorescent protein [eGFP (or DsRed)] genes. The self-assembly activity of hFTN-H that leads to the formation of nanoparticles (12 nm in diameter), the conformational flexibility of the C-terminus of hFTN-H, and the glycine-rich spacer enabled eGFPs (or DsReds) to be well displayed on the surface of each ferritin nanoparticle, resulting in the construction of green (or red) FFNPs [gFFNPs (or rFFNPs)]. As compared to eGFP (or DsRed) alone, it is notable that the developed FFNPs showed significantly amplified fluorescence intensity and also enhanced stability. DNA aptamers were chemically conjugated to gFFNP via each eGFP's cysteine residue that was newly introduced through site-directed mutagenesis (Ser175Cys). The DNA-aptamer-conjugated gFFNPs were used as a fluorescent reporter probe in the aptamer-based "sandwich" assay of a cancer marker [i.e., platelet-derived growth factor B-chain homodimer (PDGF-BB)] in phosphate-buffered saline buffer or diluted human serum. This is a simple two-step assay without any additional steps for signal amplification, showing that compared to the same aptamer-based assays using eGFP alone or Cy3, the detection signals, affinity of the reporter probe to the cancer marker, and assay sensitivity were significantly enhanced; i.e., the limit of detection was lowered to the 100 fM level. Although the PDGF-BB assay is reported here as a proof-of-concept, the developed FFNPs can be applied in general to any aptamer-based sandwich assays.     

Total oxidation of propane over Cu-Mn mixed oxide catalysts prepared by co-precipitation method

The catalytic activity of Cu-Mn mixed oxides with varying Cu/Mn ratios prepared by co-precipitation method was examined for the total oxidation of propane. The nature and phase of the metal oxide species formed were characterized by various methods such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H₂ temperature-programmed reduction (TPR) as well as BET surface area measurement. The co-precipitation method provides highly interdispersed copper and manganese metallic elements forming Cu-Mn mixed oxide of spinel structure (Cu_1.5 Mn_1.5O₄). Besides the spinel-type Cu-Mn mixed oxide, CuO or Mn₂O₃ phases could be formed depending on the Cu/Mn molar ratio of their precursors. The catalytic activity of Cu-Mn mixed oxide catalyst for propane oxidation was much higher than those of single metal oxides of CuO and Mn₂O₃. The higher catalytic activity likely originates from a synergic effect of spinel-type Cu-Mn mixed oxide and CuO. The easier reducibility and BET surface area seems to be partially responsible for the high activity of Cu-Mn mixed oxide for total oxidation of propane.     

Enzyme-derived deer velvet extract activate the immune response in cyclophosphamide-induced immunosuppressive mice

Deer velvet (DV) is an oriental traditional medicine used to treat various diseases. The present study examined the effect of flavourzyme-derived DV extract (YC-1101) on macrophages and an immunosuppressed mouse model. YC-1101 induced activation of macrophages as measured by nitric oxide production, cell proliferation, and cytokine release via concentration-dependent phosphorylation of c-Jun N-terminal kinase, extracellular signal-regulated kinase, and AKT, and nuclear translocation of p65 in macrophages. In addition, oral YC-1101 administration significantly increased splenocyte proliferation and natural killer cell activity in the immunosuppressed mouse model. Moreover, the levels of immune-related cytokines such as tumor necrotic factor-α, interferon-γ, and interleukin-2 were significantly increased by YC-1101 treatment comparable to the control group. Thus, these results suggest that YC-1101 is an efficient natural ingredient that has an immune-enhancing effect, and it might be a potential functional food for improving immunity.

     

Effects and Mechanism of Particulate Matter on Tendon Healing Based on Integrated Analysis of DNA Methylation and RNA Sequencing Data in a Rat Model

Exposure to particulate matter (PM) has been linked with the severity of various diseases. To date, there is no study on the relationship between PM exposure and tendon healing. Open Achilles tenotomy of 20 rats was performed. The animals were divided into two groups according to exposure to PM: a PM group and a non-PM group. After 6 weeks of PM exposure, the harvest and investigations of lungs, blood samples, and Achilles tendons were performed. Compared to the non-PM group, the white blood cell count and tumor necrosis factor-alpha expression in the PM group were significantly higher. The Achilles tendons in PM group showed significantly increased inflammatory outcomes. A TEM analysis showed reduced collagen fibrils in the PM group. A biomechanical analysis demonstrated that the load to failure value was lower in the PM group. An upregulation of the gene encoding cyclic AMP response element-binding protein (CREB) was detected in the PM group by an integrated analysis of DNA methylation and RNA sequencing data, as confirmed via a Western blot analysis showing significantly elevated levels of phosphorylated CREB. In summary, PM exposure caused a deleterious effect on tendon healing. The molecular data indicate that the action mechanism of PM may be associated with upregulated CREB signaling.     

Quality characteristics of fermented sausage prepared with soy sauce

Food Science and Biotechnology - The contributions of soy sauce to the quality characteristics of fermented sausages were investigated. The number of lactic acid bacteria in sausages prepared with...     

Synthesis of silver nanostructures on polytetrafluoroethylene (PTFE) using electron beam irradiation for antimicrobacterial effect

Polytetrafluoroethylene (PTFE, Teflon), a frequently utilized polymer for the fabrication of synthetic vascular graft, was surface-modified by electron beam irradiation. At the same time, the silver nanostructures were obtained on PTFE surface when exposed to an electron beam in silver ion solution. Results from FE-SEM characterization revealed that morphologies of the prepared silver nanostructures were in different shapes and sizes. The effect of electron beam current and the irradiation time on silver nanostructures formations were also investigated. In addition, we found that these prepared silver nanostructures on PTFE surface exhibited antimicrobial effect through qualitative evaluation method against Escherichia coli (ATCC 8739). This approach offered a new route for preparing silver nanostructures under electron beam irradiation, and the resulting PTFE vascular graft could be used as biocidal medical device.     

Formation behavior of anodic TiO2 nanombes in fluoride containing electrolytes

TiO₂ nanotube layers can be formed with titanium in the electrolytes containing fluoride by electrochemical method. The role of fluoride ion, the crystallinity of the anodic oxide, and the chemical state were investigated. The results show the anodic film is composed of oxide and a little amount of hydroxide. The presence of F⁻ ions leads to chemical dissolution of Ti oxide layer and prevents hydroxide precipitation. Consequently, chemical dissolution rate increases with increasing the fluoride content in the range of 0–2% (in mass fraction) because F⁻ ions in electrolyte attack the interface and allow the ions of the electrolyte to easily penetrate into the interface. The as-anodized TiO₂ nanotubes exhibit an amorphous structure. Thermally treated nanotubes are composed of mixtures of the anatase and rutile phases.     

A GC-MS based metabolic profiling of fermented sausage supplemented with pineapple

Food Science and Biotechnology - A GC-MS based metabolomic study was performed to understand metabolic changes during sausage fermentation and to investigate how the incorporation of pineapple...