Magnetic interaction in superparamagnetic Co-Pt nanoparticles synthesized in protein crystal

We synthesized Co-Pt nanoparticles in a crystal composed of proteins with a cage structure (i.e., Pyrococcus furiosus virus-like particle (PfV)) and investigated their magnetic interactions. When the soaking concentrations of metal, Co, and Pt ions in the PfV crystal were below 5.5 mM, isolated Co-Pt nanoparticles were formed. The size of the primary particles was 2-3 nm, which was smaller than the inner core size of the cage structure. When the soaking concentrations increased above 11 mM, the Co-Pt nanoparticles formed aggregates exceeding 30 nm in size. The synthesized nanoparticles showed superparamagnetic behavior at 300 K, independent of the soaking concentration. The temperature dependence of the AC magnetic susceptibility and remanent magnetization curve verified the occurrence of magnetic interactions between the Co-Pt nanoparticles. These measurements revealed that the dipolar-dipolar interaction was significant in the closely packed isolated nanoparticles, whereas it was weaker in the aggregated Co-Pt nanoparticles, probably due to the increased distance between the particles.Tagata K., Kanda D., Kobayashi N., et al. Magnetic interaction in superparamagnetic Co-Pt nanoparticles synthesized in protein crystal. IEEE Transactions on Magnetics , (2023); https://doi.org/10.1109/TMAG.2023.3290367

Accuracy management survey of nucleic acid amplification tests using inactivated SARS-CoV-2 in Hiroshima Prefecture

At the beginning of 2020, the number of laboratories performing SARS-CoV-2 testing increased with the rapid expansion of COVID-19 in Hiroshima Prefecture. Thus, it is necessary to compare and verify the validity of the test results among local laboratories. In this study, we distributed the same standard samples to laboratories that performed COVID-19 testing using the nucleic acid amplification method and confirmed the accuracy of the tests. The SARS-CoV-2 strain distributed by the National Institute of Infectious Diseases (NIID), Japan, was used for testing. As measured by RT-qPCR, a specific amount of the virus was inactivated by ethanol and dried as specimens for distribution. This study included 27 tests performed at 15 laboratories conducting or planning to conduct nucleic acid amplification tests (RT-qPCR and LAMP methods) for SARSCoV-2. The detection limit of each test method was set at the value provided by the NIID. The accuracy of the tests was examined to determine whether they met the required accuracy criteria. SARS-CoV-2 genomic RNA was reliably detected in all 27 tests. The inactivated specimens used in this study were safe to distribute and could be used as positive controls for all methods.This study was supported by a grant from the Government-Academia Collaboration of Hiroshima Prefecture and by a research grant for COVID-19 from AMED, Japan under Grant Number 20he0622011h0001(to J. T.)

Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source

Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a wellcharacterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 mu m diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 angstrom ngstrom were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here.11Ysciescopu

Characterisation of a diazinon-metabolising glutathione S-transferase in the silkworm Bombyx mori by X-ray crystallography and genome editing analysis

Abstract Previously, we found an unclassified glutathione S-transferase 2 (bmGSTu2) in the silkworm Bombyx mori that conjugates glutathione to 1-chloro-2,4-dinitrobenzene and also metabolises diazinon, an organophosphate insecticide. Here, we provide a structural and genome-editing characterisation of the diazinon-metabolising glutathione S-transferase in B. mori. The structure of bmGSTu2 was determined at 1.68 Å by X-ray crystallography. Mutation of putative amino acid residues in the substrate-binding site showed that Pro13, Tyr107, Ile118, Phe119, and Phe211 are crucial for enzymatic function. bmGSTu2 gene disruption resulted in a decrease in median lethal dose values to an organophosphate insecticide and a decrease in acetylcholine levels in silkworms. Taken together, these results indicate that bmGSTu2 could metabolise an organophosphate insecticide. Thus, this study provides insights into the physiological role of bmGSTu2 in silkworms, detoxification of organophosphate insecticides, and drug targets for the development of a novel insecticide

Magnetic interaction in superparamagnetic Co-Pt nanoparticles synthesized in protein crystal

Tagata K., Kanda D., Kobayashi N., et al. Magnetic interaction in superparamagnetic Co-Pt nanoparticles synthesized in protein crystal. IEEE Transactions on Magnetics , (2023); https://doi.org/10.1109/TMAG.2023.3290367.We synthesized Co-Pt nanoparticles in a crystal composed of proteins with a cage structure (i.e., Pyrococcus furiosus virus-like particle (PfV)) and investigated their magnetic interactions. When the soaking concentrations of metal, Co, and Pt ions in the PfV crystal were below 5.5 mM, isolated Co-Pt nanoparticles were formed. The size of the primary particles was 2-3 nm, which was smaller than the inner core size of the cage structure. When the soaking concentrations increased above 11 mM, the Co-Pt nanoparticles formed aggregates exceeding 30 nm in size. The synthesized nanoparticles showed superparamagnetic behavior at 300 K, independent of the soaking concentration. The temperature dependence of the AC magnetic susceptibility and remanent magnetization curve verified the occurrence of magnetic interactions between the Co-Pt nanoparticles. These measurements revealed that the dipolar-dipolar interaction was significant in the closely packed isolated nanoparticles, whereas it was weaker in the aggregated Co-Pt nanoparticles, probably due to the increased distance between the particles

Structural Evolution of Reoviridae Revealed by Oryzavirus in Acquiring the Second Capsid Shell▿

The conservation of the core structure and diversification of the external features among the turreted reoviruses appear to be relevant to structural evolution in facilitating the infection of diverse host species. The structure of Rice ragged stunt virus (RRSV), in the genus Oryzavirus of the family Reoviridae, is determined to show a core composed of capsid shell, clamps, and long turrets. The RRSV core structure is equivalent to the core structure of Orthoreovirus and the virion structure of Cytoplasmic polyhedrosis virus (CPV). In RRSV, five peripheral trimers surround each long turret and sit at the Q trimer position in the T=13l icosahedral symmetry, a structural feature unique to turreted reoviruses. That is, the core of RRSV is partially covered by 60 copies of the peripheral trimer. In contrast, the core of Orthoreovirus is covered by 200 copies of the trimer that sit at the Q, R, S, and T trimer positions. Our results suggest that among the three viruses, RRSV has a structure intermediate between that of Orthoreovirus and the CPV virion. This conclusion coincides with the results of the phylogenetic analysis of amino acid sequences of RNA-dependent RNA polymerases