Intra-annual fluctuation in morphology and microfibril angle of tracheids revealed by novel microscopy-based imaging

Woody cells, such as tracheids, fibers, vessels, rays etc., have unique structural characteristics such as nano-scale ultrastructure represented by multilayers, microfibril angle (MFA), micro-scale anatomical properties and spatial arrangement. Simultaneous evaluation of the above indices is very important for their adequate quantification and extracting the effects of external stimuli from them. However, it is difficult in general to achieve the above only by traditional methodologies. To overcome the above point, a new methodological framework combining polarization optical microscopy, fluorescence microscopy, and image segmentation is proposed. The framework was tested to a model softwood species, Chamaecyparis obtusa for characterizing intra-annual transition of MFA and tracheid morphology in a radial file unit. According our result, this framework successfully traced the both characteristics tracheid by tracheid and revealed the high correlation (|r| > 0.5) between S2 microfibril angles and tracheidal morphology (lumen radial diameter, tangential wall thickness and cell wall occupancy). In addition, radial file based evaluation firstly revealed their complex transitional behavior in transition and latewood. The proposed framework has great potential as one of the unique tools to provide detailed insights into heterogeneity of intra and inter-cells in the wide field of view through the simultaneous evaluation of cells’ ultrastructure and morphological properties

Construction of Tertiary Chiral Centers by Pd-catalyzed Asymmetric Allylic Alkylation of Prochiral Enolate Equivalents

The palladium-catalyzed decarboxylative allylic alkylation of enol carbonates derived from lactams and ketones is described. Employing these substrates with an electronically tuned Pd catalyst system trisubstituted chiral centers are produced. These stereocenters have been previously challenging to achieve using Pd complex/chiral P–N ligand systems

Chiral Soliton Lattice Formation in Monoaxial Helimagnet Yb(Ni1−x_{1-x}Cux_x)3_3Al9_9

Helical magnetic structures and its responses to external magnetic fields in Yb(Ni$_x$Cu$_{1-x}$)$_3$Al$_9$, with a chiral crystal structure of the space group $R32$, have been investigated by resonant X-ray diffraction. It is shown that the crystal chirality is reflected to the helicity of the magnetic structure by a one to one relationship, indicating that there exists an antisymmetric exchange interaction mediated via the conduction electrons. When a magnetic field is applied perpendicular to the helical axis ($c$ axis), the second harmonic peak of $(0, 0, 2q)$ develops with increasing the field. The third harmonic peak of $(0, 0, 3q)$ has also been observed for the $x$=0.06 sample. This result provides a strong evidence for the formation of a chiral magnetic soliton lattice state, a periodic array of the chiral twist of spins, which has been suggested by the characteristic magnetization curve. The helical ordering of magnetic octupole moments, accompanying with the magnetic dipole order, has also been detected.Comment: 13 pages, 18 figures, accepted for publication in J. Phys. Soc. Jp

Solution properties of amylose tris(3,5-dimethylphenylcarbamate) and amylose tris(phenylcarbamate): Side group and solvent dependent chain stiffness in methyl acetate, 2-butanone, and 4-methyl-2-pentanone

Five amylose tris(3,5-dimethylphenylcarbamate) (ADMPC) samples ranging in weightaverage molecular weight M w from 1.7 × 10 4 to 3.4 × 10 5 were studied by light and small-angle X-ray scattering, sedimentation equilibrium, and viscometry in methyl acetate (MEA), 2-butanone (MEK), and 4-methyl-2-pentanone (MIBK) at 25 °. Seven amylose tris(phenylcarbamate) (ATPC) samples whose M w ranges between 2 × 10 4 and 3×10 6 were also investigated in MEK at 25 °. The radii of gyration, particle scattering functions, and intrinsic viscosities determined as a function of M w were analyzed in terms of the cylindrical wormlike chain model mainly to determine the Kuhn segment length λ -1 and the contour length h (or the helix pitch) per residue. While the obtained h values (0.36-0.38 nm) of ADMPC are quite insensitive to the solvents, the λ -1 value not only is 1.5-3 times larger than that of ATPC in the corresponding solvent but also significantly increases with an increase of the molar volume of the solvent, and it reaches 73 nm in MIBK, which is the highest value for previously investigated phenylcarbamate derivatives of polysaccharides. This high stiffness is most likely due to the steric hindrance of the solvent molecules H-bonding with the NH groups of the polymer. © 2010 American Chemical Society.Tsuda M., Terao K., Nakamura Y., et al. Solution properties of amylose tris(3,5-dimethylphenylcarbamate) and amylose tris(phenylcarbamate): Side group and solvent dependent chain stiffness in methyl acetate, 2-butanone, and 4-methyl-2-pentanone. Macromolecules, 43(13), 5779-5784, June 11, 2010. Copyright © 2010, American Chemical Society. https://doi.org/10.1021/ma1006528

Chain dimensions and hydration behavior of collagen model peptides in aqueous solution: [Glycyl-4(R)-hydroxyprolyl-4(R)-hydroxyproline]n, [Glycylprolyl-4(R)-hydroxyproline]n, and some related model peptides

Terao K., Mizuno K., Murashima M., et al. Chain dimensions and hydration behavior of collagen model peptides in aqueous solution: [Glycyl-4(R)-hydroxyprolyl-4(R)-hydroxyproline]n, [Glycylprolyl-4(R)-hydroxyproline]n, and some related model peptides. Macromolecules, 41(19), 7203-7210, September 4, 2008. Copyright © 2008, American Chemical Society. https://doi.org/10.1021/ma800790w

Dual CRISPR-Cas3 system for inducing multi-exon skipping in DMD patient-derived iPSCs

DMD患者さん由来iPS細胞で複数のエクソンスキッピングを誘導するデュアルCRISPR-Cas3システムの開発. 京都大学プレスリリース. 2023-08-25.Exploring New Avenues in DMD Treatment: CRISPR-Cas3's Multi-Exon Skipping Approach. 京都大学プレスリリース. 2023-08-28.To restore dystrophin protein in various mutation patterns of Duchenne muscular dystrophy (DMD), the multi-exon skipping (MES) approach has been investigated. However, only limited techniques are available to induce a large deletion to cover the target exons spread over several hundred kilobases. Here, we utilized the CRISPR-Cas3 system for MES induction and showed that dual crRNAs could induce a large deletion at the dystrophin exon 45–55 region (∼340 kb), which can be applied to various types of DMD patients. We developed a two-color SSA-based reporter system for Cas3 to enrich the genome-edited cell population and demonstrated that MES induction restored dystrophin protein in DMD-iPSCs with three distinct mutations. Whole-genome sequencing and distance analysis detected no significant off-target deletion near the putative crRNA binding sites. Altogether, dual CRISPR-Cas3 is a promising tool to induce a gigantic genomic deletion and restore dystrophin protein via MES induction

Synthesis of single-phase L10-FeNi magnet powder by nitrogen insertion and topotactic extraction

Tetrataenite (L10-FeNi) is a promising candidate for use as a permanent magnet free of rare-earth elements because of its favorable properties. In this study, single-phase L10-FeNi powder with a high degree of order was synthesized through a new method, nitrogen insertion and topotactic extraction (NITE). In the method, FeNiN, which has the same ordered arrangement as L10-FeNi, is formed by nitriding A1-FeNi powder with ammonia gas. Subsequently, FeNiN is denitrided by topotactic reaction to derive single-phase L10-FeNi with an order parameter of 0.71. The transformation of disordered-phase FeNi into the L10 phase increased the coercive force from 14.5 kA/m to 142 kA/m. The proposed method not only significantly accelerates the development of magnets using L10-FeNi but also offers a new synthesis route to obtain ordered alloys in non-equilibrium states

Parental legacy and regulatory novelty in Brachypodium diurnal transcriptomes accompanying their polyploidy

Polyploidy is a widespread phenomenon in eukaryotes that can lead to phenotypic novelty and has important implications for evolution and diversification. The modification of phenotypes in polyploids relative to their diploid progenitors may be associated with altered gene expression. However, it is largely unknown how interactions between duplicated genes affect their diurnal expression in allopolyploid species. In this study, we explored parental legacy and hybrid novelty in the transcriptomes of an allopolyploid species and its diploid progenitors. We compared the diurnal transcriptomes of representative Brachypodium cytotypes, including the allotetraploid Brachypodium hybridum and its diploid progenitors Brachypodium distachyon and Brachypodium stacei. We also artificially induced an autotetraploid B. distachyon. We identified patterns of homoeolog expression bias (HEB) across Brachypodium cytotypes and time-dependent gain and loss of HEB in B. hybridum. Furthermore, we established that many genes with diurnal expression experienced HEB, while their expression patterns and peak times were correlated between homoeologs in B. hybridum relative to B. distachyon and B. stacei, suggesting diurnal synchronization of homoeolog expression in B. hybridum. Our findings provide insight into the parental legacy and hybrid novelty associated with polyploidy in Brachypodium, and highlight the evolutionary consequences of diurnal transcriptional regulation that accompanied allopolyploidy