Genomic surveillance of Neisseria gonorrhoeae to investigate the distribution and evolution of antimicrobial-resistance determinants and lineages

The first extensively drug resistant (XDR) Neisseria gonorrhoeae strain with high resistance to the extended-spectrum cephalosporin ceftriaxone was identified in 2009 in Japan, but no other strain with this antimicrobial-resistance profile has been reported since. However, surveillance to date has been based on phenotypic methods and sequence typing, not genome sequencing. Therefore, little is known about the local population structure at the genomic level, and how resistance determinants and lineages are distributed and evolve. We analysed the whole-genome sequence data and the antimicrobial-susceptibility testing results of 204 strains sampled in a region where the first XDR ceftriaxone-resistant N. gonorrhoeae was isolated, complemented with 67 additional genomes from other time frames and locations within Japan. Strains resistant to ceftriaxone were not found, but we discovered a sequence type (ST)7363 sub-lineage susceptible to ceftriaxone and cefixime in which the mosaic penA allele responsible for reduced susceptibility had reverted to a susceptible allele by recombination. Approximately 85 % of isolates showed resistance to fluoroquinolones (ciprofloxacin) explained by linked amino acid substitutions at positions 91 and 95 of GyrA with 99 % sensitivity and 100 % specificity. Approximately 10 % showed resistance to macrolides (azithromycin), for which genetic determinants are less clear. Furthermore, we revealed different evolutionary paths of the two major lineages: single acquisition of penA X in the ST7363-associated lineage, followed by multiple independent acquisitions of the penA X and XXXIV in the ST1901-associated lineage. Our study provides a detailed picture of the distribution of resistance determinants and disentangles the evolution of the two major lineages spreading worldwide

The potential role of temperate Japanese regions as refugia for the coral Acropora hyacinthus in the face of climate change

As corals in tropical regions are threatened by increasing water temperatures, poleward range expansion of reef-building corals has been observed, and temperate regions are expected to serve as refugia in the face of climate change. To elucidate the important indicators of the sustainability of coral populations, we examined the genetic diversity and connectivity of the common reef-building coral Acropora hyacinthus along the Kuroshio Current, including recently expanded (<50 years) populations. Among the three cryptic lineages found, only one was distributed in temperate regions, which could indicate the presence of Kuroshio-associated larval dispersal barriers between temperate and subtropical regions, as shown by oceanographic simulations as well as differences in environmental factors. The level of genetic diversity gradually decreased towards the edge of the species distribution. This study provides an example of the reduced genetic diversity in recently expanded marginal populations, thus indicating the possible vulnerability of these populations to environmental changes. This finding underpins the importance of assessing the genetic diversity of newly colonized populations associated with climate change for conservation purposes. In addition, this study highlights the importance of pre-existing temperate regions as coral refugia, which has been rather underappreciated in local coastal management

Photoinduced swing of a diarylethene thin broad sword shaped crystal:a study on the detailed mechanism

We report a swinging motion of photochromic thin broad sword shaped crystals upon continuous irradiation with UV light. By contrast in thick crystals, photosalient phenomena were observed. The bending and swinging mechanisms are in fact due to molecular size changes as well as phase transitions. The first slight bending away from the light source is due to photocyclization-induced surface expansion, and the second dramatic bending toward UV incidence is due to single-crystal-to-single-crystal (SCSC) phase transition from the original phase I to phase IIUV. Upon visible light irradiation, the crystal returned to phase I. A similar SCSC phase transition with a similar volume decrease occurred by lowering the temperature (phase IIItemp). For both photoinduced and thermal SCSC phase transitions, the symmetry of the unit cell is lowered; in phase IIUV the twisting angle of disordered phenyl groups is different between two adjacent molecules, while in phase IIItemp, the population of the phenyl rotamer is different between adjacent molecules. In the case of phase IIUV, we found thickness dependent photosalient phenomena. The thin broad sword shaped crystals with a 3 mu m thickness showed no photosalient phenomena, whereas photoinduced SCSC phase transition occurred. In contrast, large crystals of several tens of mu m thickness showed photosalient phenomena on the irradiated surface where SCSC phase transition occurred. The results indicated that the accumulated strain, between isomerized and non-isomerized layers, gave rise to the photosalient phenomenon

骨芽細胞系列細胞のビタミンD受容体は、in vivo において1α,25(OH)2D3の骨吸収促進活性に必須である

要旨我々は以前、活性型ビタミンD3 [1α,25(OH)2D3]製剤であるエルデカルシトールの薬用量の投与は、骨吸収を抑制することで、骨量を増加させることを報告した。この骨吸収抑制効果は、骨芽細胞系列細胞のビタミンD受容体（VDR）を介することを明らかにした。本研究において我々は、骨芽細胞系列細胞特異的VDR欠損（Ob-VDR-cKO）マウスを用いて、1α,25(OH)2D3の大量投与によって誘導される骨吸収促進が骨芽細胞系列細胞のVDRを介するか否かを調べた。4日間の野生型マウスへの1α,25(OH)2D3（5 µg/kg体重/日）投与は、骨における破骨細胞数を増加させ、骨吸収マーカーであるI型コラーゲンC末端テロペプチド（C-terminal crosslinked telopeptide of type I collagen, CTX-I）の血清濃度を上昇させた。骨吸収促進は、血清カルシウム（Ca）値、線維芽細胞増殖因子23（Fibroblast Growth Factor, FGF-23）値の上昇と、体重の減少を伴っていた。このことは、中毒量の1α,25(OH)2D3は、骨吸収促進と高Ca血症を誘導することを示している。対照的に、野生型マウスへの抗Receptor Activator of NF-κB Ligand（RANKL）中和抗体前投与は、1α,25(OH)2D3が誘導する血清CTX-I, CaおよびFGF23値の上昇を抑制した。また、抗RANKL中和抗体前投与は、1α,25(OH)2D3が誘導する体重減少を抑制した。抗RANKL中和抗体前投与マウスの所見と一致して、1α,25(OH)2D3をOb-VDR-cKOマウスに大量投与しても、破骨細胞数、血清CTX-I値、血清Ca値、血清FGF-23値は、有意に上昇せず、また体重も減少しなかった。以上、本研究において、1α,25(OH)2D3の大量投与による骨吸収促進、血清Ca値上昇および毒性作用は、骨芽細胞系列細胞のVDRを介して発揮されることを明らかにした。2020博士（歯学）松本歯科大

Cloning and Characterization of the Antiviral Activity of Feline Tetherin/BST-2

Human Tetherin/BST-2 has recently been identified as a cellular antiviral factor that blocks the release of various enveloped viruses. In this study, we cloned a cDNA fragment encoding a feline homolog of Tetherin/BST-2 and characterized the protein product. The degree of amino acid sequence identity between human Tetherin/BST-2 and the feline homolog was 44.4%. Similar to human Tetherin/BST-2, the expression of feline Tetherin/BST-2 mRNA was inducible by type I interferon (IFN). Exogenous expression of feline Tetherin/BST-2 efficiently inhibited the release of feline endogenous retrovirus RD-114. The extracellular domain of feline Tetherin/BST-2 has two putative N-linked glycosylation sites, N79 and N119. Complete loss of N-linked glycosylation by introduction of mutations into both sites resulted in almost complete abolition of its antiviral activity. In addition, feline Tetherin/BST-2 was insensitive to antagonism by HIV-1 Vpu, although the antiviral activity of human Tetherin/BST-2 was antagonized by HIV-1 Vpu. Our data suggest that feline Tetherin/BST-2 functions as a part of IFN-induced innate immunity against virus infection and that the induction of feline Tetherin/BST-2 in vivo may be effective as a novel antiviral strategy for viral infection