Infrared spectroscopy analysis determining secondary structure change in albumin by cerium oxide nanoparticles

Cerium oxide (CeO2) nanoparticles are expected to have applications in the biomedical field because of their antioxidative properties. Inorganic nanoparticles interact with proteins at the nanoparticle surface and change their conformation when administered; however, the principle underlying this interaction is still unclear. This study aimed to investigate the secondary structural changes occurring in bovine serum albumin (BSA) mixed with CeO2 nanoparticles having different surface modifications using Fourier transform infrared spectroscopy. CeO2 nanoparticles (diameter: 240 nm) were synthesized from an aqueous cerium (III) nitrate solution using a homogeneous precipitation method. The surfaces of the nanoparticles were modified by the catechol compounds dopamine and 3,4-dihydroxyhydrocinnamic acid (DHCA). In the presence of these CeO2 nanoparticles (0.11–0.43 mg/mL), β-sheet formation of BSA (30 mg/mL) was promoted especially on the amine-modified (positively charged) nanoparticles. The local concentration of BSA on the surface of the positively charged nanoparticles may have resulted in structural changes due to electrostatic and other interactions with BSA. Further investigations of the interaction mechanism between nanoparticles and proteins are expected to lead to the safe biomedical applications of inorganic nanoparticles

p62 Plays a Specific Role in Interferon-γ-Induced Presentation of a Toxoplasma Vacuolar Antigen

Also known as Sqstm1, p62 is a selective autophagy adaptor with a ubiquitin-binding domain. However, the role of p62 in the host defense against Toxoplasma gondii infection is unclear. Here, we show that interferon γ (IFN-γ) stimulates ubiquitin and p62 recruitment to T. gondii parasitophorous vacuoles (PVs). Some essential autophagy-related proteins, but not all, are required for this recruitment. Regardless of normal IFN-γ-induced T. gondii clearance activity and ubiquitination, p62 deficiency in antigen-presenting cells (APCs) and mice diminishes the robust IFN-γ-primed activation of CD8+ T cells that recognize the T. gondii-derived antigen secreted into PVs. Because the expression of Atg3 and Irgm1/m3 in APCs is essential for PV disruption, ubiquitin and p62 recruitment, and vacuolar-antigen-specific CD8+ T cell activation, IFN-γ-mediated ubiquitination and the subsequent recruitment of p62 to T. gondii are specifically required for the acquired immune response after PV disruption by IFN-γ-inducible GTPases

Piperidinium-Based Ionic Liquids as an Electrolyte Solvent for Li-Ion Batteries: Effect of Number and Position of Oxygen Atom in Cation Side Chain on Electrolyte Property

ArticleJournal of The Electrochemical Society. 167(7): 174101 (2019)journal articl

Pb/s, homogeneous, single-mode, multi-core fiber systems

We discuss multi Pb/s transmission using homogeneous, single-mode, multi-core fibers. We outline the key components of a recent high capacity demonstration, the consequences of fiber properties and the potential for enhanced efficiency from spatial-super-channel transmission

Characterization of a Fiber-Coupled 36-Core 3-Mode Photonic Lantern Spatial Multiplexer

A fiber-coupled 108-port photonic lantern spatial-MUX is characterized with a spatially-diverse optical vector network analyzer. Insertion loss, mode-dependent losses, and time response are measured, showing significant mode mixing at a fiber splice

Analysis of Few-Mode Multi-Core Fiber Splice Behavior Using an Optical Vector Network Analyzer

The behavior of splices in a 3-mode 36-core fiber is analyzed using optical vector network analysis. Time-domain response analysis confirms splices may cause significant mode-mixing, while frequency-domain analysis shows splices may affect system level mode-dependent loss both positively and negatively

Measurement of modal dispersion and group delay in a large core count few-mode multi-core fiber

\u3cp\u3eIn this work, the impulse response of a 39-core 3-mode fiber is measured and analyzed, finding durations of 0.6 ns-3.0 ns, with total group delay varying by 17 ns between cores and observing largely different modal dispersion and wavelength dependence of propagation delay.\u3c/p\u3

CHANGES IN THE SECONDARY STRUCTURE AND ASSEMBLY OF PROTEINS ON FLUORIDE CERAMIC (CEF3) NANOPARTICLE SURFACES

Fluoride nanoparticles (NPs) are materials utilized in the biomedical field for applications including imaging of the brain. Their interactions with biological systems and molecules are being investigated, but the mechanism underlying these interactions remains unclear. We focused on possible changes in the secondary structure and aggregation state of proteins on the surface of NPs and investigated the principle underlying the changes using the amyloid β peptide (Aβ16−20) based on infrared spectrometry. CeF3 NPs (diameter 80 nm) were synthesized via thermal decomposition. Infrared spectrometry showed that the presence of CeF3 NPs promotes the formation of the β-sheet structure of Aβ16−20. This phenomenon was attributed to the hydrophobic interaction between NPs and Aβ peptides in aqueous environments, which causes the Aβ peptides to approach each other on the NP surface and form ordered hydrogen bonds. Because of the coexisting salts on the secondary structure and assembly of Aβ peptides, the formation of the β-sheet structure of Aβ peptides on the NP surface was suppressed in the presence of NH4 + and NO3 − ions, suggesting the possibility that Aβ peptides were adsorbed and bound to the NP surface. The formation of the β-sheet structure of Aβ peptides was promoted in the presence of NH4 + , whereas it was suppressed in the presence of NO3 − because of the electrostatic interaction between the lysine residue of the Aβ peptide and the ions. Our findings will contribute to comparative studies on the effect of different NPs with different physicochemical properties on the molecular state of proteins

In-Orbit Demonstration of Propellant-Less Formation Flight with Momentum Exchange of Jointed Multiple CubeSats in the MAGNARO Mission

Recently, small satellites such as CubeSats have been applied to a variety of missions such as scientific observations and remote sensing. One of attractive applications that can be relatively easily achieved by small satellites are multi-satellite missions such as formation flight and constellation. As a new method to realize these multi-satellite missions, we propose a method to separate jointed multiple satellite magnetically to generate ΔV without thrusters. To demonstrate the proposed method, we are developing a 3U sized CubeSat called MAGNARO (MAGnetically separating NAnosatellite with Rotation for Orbit control)