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The liverwort Marchantia polymorpha is equipped with a wide range of molecular and genetic tools and resources that have led to its wide use to explore the evo-devo aspects of land plants. Although its diverse transcriptome data are rapidly accumulating, there is no extensive yet user-friendly tool to exploit such a compilation of data and to summarize results with the latest annotations. Here, we have developed a web-based suite of tools, MarpolBase Expression (MBEX, https://marchantia.info/mbex/), where users can visualize gene expression profiles, identify differentially expressed genes, perform co-expression and functional enrichment analyses, and summarize their comprehensive output in various portable formats. Using oil body biogenesis as an example, we demonstrated that the results generated by MBEX were consistent with the published experimental evidence and also revealed a novel transcriptional network in this process. MBEX should facilitate the exploration and discovery of the genetic and functional networks behind various biological processes in M. polymorpha, and promote our understanding of the evolution of land plants.

Regeneration in land plants is accompanied by the establishment of new stem cells, which often involves reactivation of the cell division potential in differentiated cells. The phytohormone auxin plays pivotal roles in this process. In bryophytes, regeneration is enhanced by the removal of the apex and repressed by exogenously applied auxin, which has long been proposed as a form of apical dominance. However, the molecular basis behind these observations remains unexplored. Here, we demonstrate that in the liverwort Marchantia polymorpha, the level of endogenous auxin is transiently decreased in the cut surface of decapitated explants, and identify by transcriptome analysis a key transcription factor gene, LOW-AUXIN RESPONSIVE (MpLAXR), which is induced upon auxin reduction. Loss of MpLAXR function resulted in delayed cell cycle reactivation, and transient expression of MpLAXR was sufficient to overcome the inhibition of regeneration by exogenously applied auxin. Furthermore, ectopic expression of MpLAXR caused cell proliferation in normally quiescent tissues. Together, these data indicate that decapitation causes a reduction of auxin level at the cut surface, where, in response, MpLAXR is up-regulated to trigger cellular reprogramming. MpLAXR is an ortholog of Arabidopsis ENHANCER OF SHOOT REGENERATION 1/DORNRÖSCHEN, which has dual functions as a shoot regeneration factor and a regulator of axillary meristem initiation, the latter of which requires a low auxin level. Thus, our findings provide insights into stem cell regulation as well as apical dominance establishment in land plants.

A water solubilization technique using biocompatible polypeptides via a mechanochemical approach was developed for the issues in the pharmaceutical industry.

Polypeptides were used to solubilize functional hydrophobic molecules via a high-speed vibrational milling method.

In this study, we evaluated the dependence of magnetization of three-dimensional Dirac electrons in the quantum limit on the magnetic field and temperature. The magnetization was calculated by differentiating the free energy with respect to the magnetic field. The field and temperature dependence of the chemical potential were entirely considered under the canonical ensemble condition. The total magnetization M consisted of two contributions from the conduction M c and valence M v bands. M v was insensitive to temperature and exhibited sub-linear field dependence, which is consistent with the previous research on Dirac electrons. By contrast, M c was sensitive to both temperature and magnetic field, yielding a non-trivial contribution to the total M. As a result, the properties of total M changed at approximately k B T ≃ E F , where E F is the Fermi energy measured from the band bottom and k B is the Boltzmann constant. At low temperatures k B T ≲ E F , M exhibited sub-linear field dependence, whereas M exhibited super-linear field dependence at high temperatures k B T ≳ E F . This qualitative change in the field dependence of M will play a significant role in the magnetization of Dirac electrons with small E F .

Hydrogen sulfide (H2S) is a signaling molecule whose overexpression is identified in various cancers. Despite the flourishing research of H2S-responsive nanomaterials, the development of H2S-respon...

Sex determination is a central process for sexual reproduction and is often regulated by a sex determinant encoded on a sex chromosome. Rules that govern the evolution of sex chromosomes via specialization and degeneration following the evolution of a sex determinant have been well studied in diploid organisms. However, distinct predictions apply to sex chromosomes in organisms where sex is determined in the haploid phase of the life cycle: both sex chromosomes, female U and male V, are expected to maintain their gene functions, even though both are non-recombining. This is in contrast to the X-Y (or Z-W) asymmetry and Y (W) chromosome degeneration in XY (ZW) systems of diploids. Here, we provide evidence that sex chromosomes diverged early during the evolution of haploid liverworts and identify the sex determinant on the Marchantia polymorpha U chromosome. This gene, Feminizer, encodes a member of the plant-specific BASIC PENTACYSTEINE transcription factor family. It triggers female differentiation via regulation of the autosomal sex-determining locus of FEMALE GAMETOPHYTE MYB and SUPPRESSOR OF FEMINIZATION. Phylogenetic analyses of Feminizer and other sex chromosome genes indicate dimorphic sex chromosomes had already been established 430 mya in the ancestral liverwort. Feminizer also plays a role in reproductive induction that is shared with its gametolog on the V chromosome, suggesting an ancestral function, distinct from sex determination, was retained by the gametologs. This implies ancestral functions can be preserved after the acquisition of a sex determination mechanism during the evolution of a dominant haploid sex chromosome system., 半数体生物の性染色体上の性決定遺伝子を解明 --コケがもつ現生生物最古の起源の性染色体--. 京都大学プレスリリース. 2021-11-08.

The reaction pressure in the photocatalytic conversion of CO 2 into fuels is optimized between 0 and 0.80 MPa under CO 2 and moisture. The higher reactivity of water than H 2 was observed at higher pressure and the reason was clarified using several ∼10-μm-thick semiconductor-based photocatalysts. The best Pd/TiO 2 photocatalyst produces methane with a reaction order of 0.39. The sum of independent total formation rates of C-containing compounds under UV and visible light does not account for that under UV–visible light, demonstrating synergetic reaction mechanism on Pd for CO 2 reduction by excited electrons via surface plasmon resonance and on TiO 2 for water oxidation. Active metallic Pd and O vacancy sites due to O 2 formation from H 2 O are confirmed by in situ monitoring of EXAFS [ N (Pd–Pd) = 5.9–6.2; N (Ti–O) = 5.2–3.5] and the decrease of the H-bound and bi/tri-coordinated OH peaks in FTIR. Effective redox-site separation explains the higher reactivity of water than H 2 .

Photocatalytic conversion of CO 2 into fuels could mitigate global warming and energy shortage simultaneously. In this study, the reaction pressure was optimized for CO 2 reduction by H 2 . The major products were methane, CO, and methanol, and the observed catalytic activity order was Cu or Pd on TiO 2 ≫ Ag/ZrO 2 ∼ g-C 3 N 4 > Ag/Zn 3 Ga-layered double hydroxide ∼ BiOCl. Hot/excited electrons due to surface plasmon resonance could be transferred to CO 2 -derived species and the remaining positive charge could combine with excited electrons in the semiconductor. As the levels of hot/excited electrons became more negative, the catalysts became more active, except for Ag/ZrO 2 and Ag/Zn 3 Ga-LDH, probably due to lower charge separation efficiency for intrinsic semiconductors or hydroxides. The reaction order was controlled by the partial pressure of H 2 , demonstrating preferable adsorption of H on Pd. The photoconversion of CO 2 into methane was optimum at P H2 = 0.28 MPa and P CO2 = 0.12 MPa, but the rates gradually dropped at higher partial pressures due to adsorption of CO 2 being hindered by H.

a b s t r a c t In the search for novel efficient photocatalysts for the conversion of CO2 into fuels, plasmonic photocata- lysts based on the self-assemblies of silver or gold nanoparticles with (Zn3Ga(OH)8)2CO3·mH2O layered double hydroxide (Zn3Ga|CO3 LDH) were prepared and tested for the photoreduction of CO2 by H2 under irradiation with UV-visible light. Ag and Au nanoparticles were obtained directly on the LDHs via the ion-exchange method or the reconstruction method of the LDHs. The catalysts exhibited intense surface plasmon resonance (SPR) effect at 411 and 555 nm attributable to Ag and Au nanoparticles, respectively. The rate of CO2 photoreduction on Ag/Zn3Ga|CO3 increased by a factor of 1.69 than that of Zn3Ga|CO3 while the methanol selectivity also increased from 39 to 54 mol%. On Au/Zn3Ga|CO3, the reduction rate of CO2 was 1.78 times higher than on Zn3Ga|CO3 LDH whereas the methanol selectivity decreased from 39 to 13 mol%. Electron microscopy and UV-visible and X-ray spectroscopy detected particular interactions of the cationic layers of Zn3Ga|CO3 with Ag and Au nanoparticles. Results show that for Ag/Zn3Ga|CO3 cat- alysts, CO2 photoreduction by H2 under visible light was promoted by the SPR effect of Ag nanoparticles while for Au/Zn3Ga|CO3 catalysts Au nanoparticles might act as electron-trapping active sites.

Photocatalytic conversion of CO2 into fuels is an attractive option in terms of both reducing the increased concentration of atmospheric CO2 as well as generating renewable hydrocarbon fuels. It is necessary to investigate good catalysts for CO2 conversion and to clarify the mechanism irradiated by natural light. Layered Double Hydroxides (LDH) have been attracting attention for CO2 photoreduction with the expectation of sorption capacity for CO2 in the layered space and tunable semiconductor properties as a result of the choice of metal cations. This study first clarifies the effects of Cu doping to LDH comprising Zn and Al or Ga. Cu could be incorporated in the cationic layers of LDH as divalent metal cations and/or interlayer anions as Cu(OH)4 2− . The formation rates of methanol and CO were optimized for [Zn1.5 Cu1.5 Ga(OH)8 ]+ 2 Cu(OH)4 2− ·mH2 O at a total rate of 560 nmol h−1 gcat −1 irradiated by UV–visible light. Cu phthalocyanine tetrasulfonate hydrate (CuPcTs4− ) and silver were effective as promoters of LDH for CO2 photoreduction. Especially, the total formation rate using CuPcTs-[Zn3 Ga(OH)8 ]+ 2 CO3 2− ·mH2 O irradiated by visible light was 73% of that irradiated by UV–visible light. The promotion was based on HOMO–LUMO excitation of CuPcTs4− by visible light. The LUMO was distributed on N atoms of pyrrole rings bound to central Cu2+ ions. The photogenerated electrons diffused to the Cu site would photoreduce CO2 progressively in a similar way to inlayer and interlayer Cu sites in the LDH in this study.

Solar cells and fuel cells have been extensively investigated. However, the need for sustainability, durability, and an electromotive force greater than 1.5 V per cell has not yet been fully realized. Herein, a photofuel cell (PFC) comprising two photocatalysts TiO2 and BiOCl that uses acidic water as a fuel is described. The PFC is designed such that water can be regenerated from the photogenerated O2 in the cell, and the electromotive force is as high as the difference between the conduction band minimum of TiO2 and the valence band maximum of BiOCl (theoretical: 2.75 V, experimental: 1.76 V). The photocurrents were in accordance with a kinetic model based on the combination of the excited electron concentration at TiO2 and the hole concentration at BiOCl. The reaction between the surface sites of O and/or Cl-deficient BiO1−xCl1−y species formed by ultraviolet-visible light irradiation with O2 was in situ monitored using Bi L3-edge extended X-ray absorption fine structure and X-ray photoelectron spectroscopy supported by Raman and UV-visible spectroscopy and could be involved in the cathodic O2 photoreduction in the PFC. Furthermore, amorphous-like BiO1−xCl species were observed on the surface of the BiOCl crystallites in high-resolution transmission electron microscopy. Importantly, this PFC that comprises TiO2 and BiOCl is sustainable, recyclable, and has a series resistance that can be controlled by adjusting the BiOCl particle size, and exhibits a more efficient charge flow because of band bending than that of a previously reported PFC based on the rectification of the Schottky barrier.

The phenomena of the photocatalytic oxidation of water and photocatalytic reduction of CO2 were combined using reverse photofuel cells, in which the two photocatalysts, WO3 and layered double hydroxide (LDH), were separated by a polymer electrolyte (PE) film. WO3 was used for the photooxidation of water, whereas LDH, comprising Zn, Cu, and Ga, was used for the photoreduction of CO2. For this process, photocatalysts pressed on both sides of the PE film were irradiated with UV-visible light through quartz windows and through the space in carbon electrode plates and water-repellent carbon paper for both gas flow and light transmission. 45% of the photocatalyst area was irradiated through the windows. The protons and electrons, which were formed on WO3 under the flow of helium and moisture, transferred to the LDH via the PE and external circuit, respectively. Methanol was the major product from the LDH under the flow of CO2 and helium. The observed photoreduction rates of CO2 to methanol accounted for 68%–100% of photocurrents. This supports the effectiveness of the combined photooxidation and photoreduction mechanism as a viable strategy to selectively produce methanol. In addition, we tested reverse photofuel cell-2, which consisted of a WO3 film pressed on C paper and LDH film pressed on Cu foil. The photoelectrodes were immersed in acidic solutions of pH 4, with the PE film distinguishing the two compartments. Both the photoelectrodes were completely irradiated by UV-visible light through the quartz windows. Consequently, the photocurrent from the LDH under CO2 flow to WO3 under N2 flow was increased by 2.4–3.4 times in comparison to photofuel cell-1 tested under similar conditions. However, the major product from the LDH was H2 rather than methanol using photofuel cell-2. The photogenerated electrons in the irradiated area of the photocatalysts were obliged to diffuse laterally to the unirradiated area of photocatalysts in contact with the C papers in photofuel cell-1. This lateral diffusion reduced the photocatalytic conversion rates of CO2, despite the advantages of photofuel cell-1 in terms of selective formation and easy separation of gas-phase methanol.