Thermal Studies of Some Minerals, No. 2

For the purpose of discerning the inner structures of chlorite group from one another, thermal variations of the related specimens collected from a chromite deposit in serpentinite have been continuously traced during the heated states at various temperatures up to ca. 950°C kept respectively for long enough hours by means of X-ray diffractometer ac-companying the specific heating apparatus and a few data obtained through infra-red absorption have been added to for reference.今村外治教授退官記念特集

Suppression of HBV replication by the expression of nickase-and nuclease dead-Cas9

Kurihara, T., Fukuhara, T., Ono, C. et al. Suppression of HBV replication by the expression of nickase- and nuclease dead-Cas9. Sci Rep 7, 6122 (2017). https://doi.org/10.1038/s41598-017-05905-

Ultrasensitive detection of SARS-CoV-2 nucleocapsid protein using large gold nanoparticle-enhanced surface plasmon resonance

The COVID-19 pandemic has created urgent demand for rapid detection of the SARS-CoV-2 coronavirus. Herein, we report highly sensitive detection of SARS-CoV-2 nucleocapsid protein (N protein) using nanoparticle-enhanced surface plasmon resonance (SPR) techniques. A crucial plasmonic role in significantly enhancing the limit of detection (LOD) is revealed for exceptionally large gold nanoparticles (AuNPs) with diameters of hundreds of nm. SPR enhanced by these large nanoparticles lowered the LOD of SARS-CoV-2 N protein to 85 fM, resulting in the highest SPR detection sensitivity ever obtained for SARS-CoV-2 N protein

Intranasal immunization with an RBD-hemagglutinin fusion protein harnesses preexisting immunity to enhance antigen-specific responses

Kawai A., Tokunoh N., Kawahara E., et al. Intranasal immunization with an RBD-hemagglutinin fusion protein harnesses preexisting immunity to enhance antigen-specific responses. Journal of Clinical Investigation 133, e166827 (2023); https://doi.org/10.1172/JCI166827.Intranasal vaccines are anticipated to be powerful tools for combating many infectious diseases, including SARS-CoV-2, because they induce not only systemic immunity but also mucosal immunity at the site of initial infection. However, they are generally inefficient in inducing an antigen-specific immune response without adjuvants. Here, we developed an adjuvant-free intranasal vaccine platform that utilizes the preexisting immunity induced by previous infection or vaccination to enhance vaccine effectiveness. We made RBD-HA, a fusion of the receptor-binding domain (RBD) of spike derived from SARS-CoV-2 as a vaccine target with HA derived from influenza A virus (IAV) as a carrier protein. Intranasal immunization of previously IAV-infected mice with RBD-HA without an adjuvant elicited robust production of RBD-specific systemic IgG and mucosal IgA by utilizing both HA-specific preexisting IgG and CD4+ T cells. Consequently, the mice were efficiently protected from SARS-CoV-2 infection. Additionally, we demonstrated the high versatility of this intranasal vaccine platform by assessing various vaccine antigens and preexisting immunity associated with a variety of infectious diseases. The results of this study suggest the promising potential of this intranasal vaccine platform to address problems associated with intranasal vaccines

SARS-CoV-2 disrupts respiratory vascular barriers by suppressing Claudin-5 expression

臓器チップ技術を用いて新型コロナウイルスが血管へ侵入するメカニズムを解明 --Claudin-5発現抑制による呼吸器の血管内皮バリア破壊--. 京都大学プレスリリース. 2022-09-22.A study using an organ-on-a-chip reveals a mechanism of SARS-CoV-2 invasion into blood vessels --Disruption of vascular endothelial barrier in respiratory organs by decreasing Claudin-5 expression--. 京都大学プレスリリース. 2022-09-27.In the initial process of coronavirus disease 2019 (COVID-19), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects respiratory epithelial cells and then transfers to other organs the blood vessels. It is believed that SARS-CoV-2 can pass the vascular wall by altering the endothelial barrier using an unknown mechanism. In this study, we investigated the effect of SARS-CoV-2 on the endothelial barrier using an airway-on-a-chip that mimics respiratory organs and found that SARS-CoV-2 produced from infected epithelial cells disrupts the barrier by decreasing Claudin-5 (CLDN5), a tight junction protein, and disrupting vascular endothelial cadherin–mediated adherens junctions. Consistently, the gene and protein expression levels of CLDN5 in the lungs of a patient with COVID-19 were decreased. CLDN5 overexpression or Fluvastatin treatment rescued the SARS-CoV-2–induced respiratory endothelial barrier disruption. We concluded that the down-regulation of CLDN5 expression is a pivotal mechanism for SARS-CoV-2–induced endothelial barrier disruption in respiratory organs and that inducing CLDN5 expression is a therapeutic strategy against COVID-19

Baculovirus as a Tool for Gene Delivery and Gene Therapy

Based on its ability to express high levels of protein, baculovirus has been widely used for recombinant protein production in insect cells for more than thirty years with continued technical improvements. In addition, baculovirus has been successfully applied for foreign gene delivery into mammalian cells without any viral replication. However, several CpG motifs are present throughout baculoviral DNA and induce an antiviral response in mammalian cells, resulting in the production of pro-inflammatory cytokines and type I interferon through a Toll-like receptor (TLR)-dependent or -independent signaling pathway, and ultimately limiting the efficiency of transgene expression. On the other hand, by taking advantage of this strong adjuvant activity, recombinant baculoviruses encoding neutralization epitopes can elicit protective immunity in mice. Moreover, immunodeficient cells, such as hepatitis C virus (HCV)- or human immunodeficiency virus (HIV)-infected cells, are more susceptible to baculovirus infection than normal cells and are selectively eliminated by the apoptosis-inducible recombinant baculovirus. Here, we summarize the application of baculovirus as a gene expression vector and the mechanism of the host innate immune response induced by baculovirus in mammalian cells. We also discuss the future prospects of baculovirus vectors

Quantitative analysis of the formation of monodisperse cello-oligomers obtained by phosphoric acid hydrolysis

Hydrolysis of cellulose in concentrated phosphoric acid is known to give two distinctive mono-disperse cello-oligomers: the degree of polymerization (DP) of 7 and 15. To understand the formation mechanism of monodisperse cello-oligomers, the transition of DP during phosphoric hydrolysis was monitored by size-exclusion chromatography combined with multiangle laser-light scattering analyses (SEC/MALLS). The obtained results suggested that not the hydrolysis at a specific length but random hydrolysis was likely. The rate of hydrolysis slowed down when the DP reached around 40, and the pool of cello-oligomers appeared at the incubation of 35 days. Then, the mono-disperse cello-oligomers were recovered from the pool of cello-oligomers by fractionation based on the solubility difference