Pathway bias and emergence of quasi-irreversibility in reversible reaction networks: Extension of Curtin-Hammett principle

可逆な化学反応ネットワークにおける経路選択の原理 --準不可逆性の発現--. 京都大学プレスリリース. 2023-07-21.The Curtin-Hammett principle, which works in a reaction sequence where slow irreversible reactions are connected to a fast reversible reaction, determines the product distribution depending only on the relative energy barriers of the two irreversible reactions, resulting in kinetic pathway selection. A basic question is how the reaction pathway is selected in reaction networks composed of reversible reactions to generate a metastable state. Numerical simulations of model systems where reversible elementary reactions are connected linearly to an initial reversible reaction demonstrate that a metastable state far from equilibrium is transiently produced and that its lifetime is prolonged by increasing the number of connected reversible reactions. The pathway selection in the model systems originates from quasi-irreversibility, and a similar behavior was also observed in the molecular self-assembly of a Pd₆L₄ truncated tetrahedron, which supports the idea that the emergence of quasi-irreversibility is a key general concept underlining kinetic control in reversible reaction networks

A new allele of flower color gene W1 encoding flavonoid 3'5'-hydroxylase is responsible for light purple flowers in wild soybean Glycine soja

<p>Abstract</p> <p>Background</p> <p><it>Glycine soja </it>is a wild relative of soybean that has purple flowers. No flower color variant of <it>Glycine soja </it>has been found in the natural habitat.</p> <p>Results</p> <p>B09121, an accession with light purple flowers, was discovered in southern Japan. Genetic analysis revealed that the gene responsible for the light purple flowers was allelic to the <it>W1 </it>locus encoding flavonoid 3'5'-hydroxylase (F3'5'H). The new allele was designated as <it>w1-lp</it>. The dominance relationship of the locus was <it>W1 </it>><it>w1-lp </it>><it>w1</it>. One F₂plant and four F₃plants with purple flowers were generated in the cross between B09121 and a Clark near-isogenic line with <it>w1 </it>allele. Flower petals of B09121 contained lower amounts of four major anthocyanins (malvidin 3,5-di-<it>O</it>-glucoside, petunidin 3,5-di-<it>O</it>-glucoside, delphinidin 3,5-di-<it>O</it>-glucoside and delphinidin 3-<it>O</it>-glucoside) common in purple flowers and contained small amounts of the 5'-unsubstituted versions of the above anthocyanins, peonidin 3,5-di-<it>O</it>-glucoside, cyanidin 3,5-di-<it>O</it>-glucoside and cyanidin 3-<it>O</it>-glucoside, suggesting that F3'5'H activity was reduced and flavonoid 3'-hydroxylase activity was increased. F3'5'H cDNAs were cloned from Clark and B09121 by RT-PCR. The cDNA of B09121 had a unique base substitution resulting in the substitution of valine with methionine at amino acid position 210. The base substitution was ascertained by dCAPS analysis. The polymorphism associated with the dCAPS markers co-segregated with flower color in the F₂population. F₃progeny test, and dCAPS and indel analyses suggested that the plants with purple flowers might be due to intragenic recombination and that the 65 bp insertion responsible for gene dysfunction might have been eliminated in such plants.</p> <p>Conclusions</p> <p>B09121 may be the first example of a flower color variant found in nature. The light purple flower was controlled by a new allele of the <it>W1 </it>locus encoding F3'5'H. The flower petals contained unique anthocyanins not found in soybean and <it>G. soja</it>. B09121 may be a useful tool for studies of the structural and functional properties of F3'5'H genes as well as investigations on the role of flower color in relation to adaptation of <it>G. soja </it>to natural habitats.</p

Microstructured organic cavities with high-reflective flat reflectors fabricated by using a nanoimprint-bonding process

The integration of photonic microstructure into organic microcavities represents an effective strategy for manipulating eigenstates of cavity or polariton modes. However, well-established fabrication processes for microstructured organic microcavities are still lacking. In this study, we propose a nanoimprint-bonding process as a novel fabrication method for microstructured organic microcavities. This process relies on a UV nanoimprint technique utilizing two different photopolymer resins, enabling the independent fabrication of highly reflective reflectors and photonic microstructures without compromising the accuracy of each. The resulting organic microcavities demonstrate spatially localized photonic modes within dot structures and their nonlinear responses on the pumping fluence. Furthermore, a highly precise photonic band is confirmed within a honeycomb lattice structure, which is owing to the high quality factor of the cavity achievable with the nanoimprint-bonding process. Additionally, a topological edge state is also observable within a zigzag lattice structure. These results highlight the significant potential of our fabrication method for advancing organic-based photonic devices, including lasers and polariton devices

ASSOCIATIONS BETWEEN EXERCISE-INDUCED FLATTENING OF FOOT ARCH AND FATIGUE OF EXTRINSIC AND INTRINSIC FOOT MUSCLES

We aimed to examine the associations between exercise-induced flattening of the foot arch and fatigue of extrinsic and intrinsic foot muscles. Fifteen male participants repeated 100 hops/set until they could no longer maintain the hop frequency or had completed 30 sets. The sagittal plane range of motion (ROM) of the midfoot during stance phase significantly decreased at the final set compared to the initial set (-8.8°). After the fatigue task, MRI T2 relaxation time in all measured extrinsic and intrinsic foot muscles significantly increased (17.2‒37.4%); however, only its increase in the tibialis posterior (TP) correlated with the relative change in midfoot ROM (r = 0.684). These results suggest that fatigue of TP is associated with the occurrence of flattening of the foot arch. This study provides a clinical implication that monitoring midfoot kinematics can be used to assess the condition of TP

Allelic variation of soybean flower color gene W4 encoding dihydroflavonol 4-reductase 2

BACKGROUND: Flower color of soybean is primarily controlled by six genes, viz., W1, W2, W3, W4, Wm and Wp. This study was conducted to investigate the genetic and chemical basis of newly-identified flower color variants including two soybean mutant lines, 222-A-3 (near white flower) and E30-D-1 (light purple flower), a near-isogenic line (Clark-w4), flower color variants (T321 and T369) descended from the w4-mutable line and kw4 (near white flower, Glycine soja). RESULTS: Complementation tests revealed that the flower color of 222-A-3 and kw4 was controlled by the recessive allele (w4) of the W4 locus encoding dihydroflavonol 4-reductase 2 (DFR2). In 222-A-3, a single base was deleted in the first exon resulting in a truncated polypeptide consisting of 24 amino acids. In Clark-w4, base substitution of the first nucleotide of the fourth intron abolished the 5′ splice site, resulting in the retention of the intron. The DFR2 gene of kw4 was not expressed. The above results suggest that complete loss-of-function of DFR2 gene leads to near white flowers. Light purple flower of E30-D-1 was controlled by a new allele at the W4 locus, w4-lp. The gene symbol was approved by the Soybean Genetics Committee. In E30-D-1, a single-base substitution changed an amino acid at position 39 from arginine to histidine. Pale flowers of T369 had higher expression levels of the DFR2 gene. These flower petals contained unique dihydroflavonols that have not yet been reported to occur in soybean and G. soja. CONCLUSIONS: Complete loss-of-function of DFR2 gene leads to near white flowers. A new allele of the W4 locus, w4-lp regulates light purple flowers. Single amino acid substitution was associated with light purple flowers. Flower petals of T369 had higher levels of DFR2 gene expression and contained unique dihydroflavonols that are absent in soybean and G. soja. Thus, mutants of the DFR2 gene have unique flavonoid compositions and display a wide variety of flower color patterns in soybean, from near white, light purple, dilute purple to pale