Understanding the charge transfer effects of single atoms for boosting the performance of Na-S batteries.

The effective flow of electrons through bulk electrodes is crucial for achieving high-performance batteries, although the poor conductivity of homocyclic sulfur molecules results in high barriers against the passage of electrons through electrode structures. This phenomenon causes incomplete reactions and the formation of metastable products. To enhance the performance of the electrode, it is important to place substitutable electrification units to accelerate the cleavage of sulfur molecules and increase the selectivity of stable products during charging and discharging. Herein, we develop a single-atom-charging strategy to address the electron transport issues in bulk sulfur electrodes. The establishment of the synergistic interaction between the adsorption model and electronic transfer helps us achieve a high level of selectivity towards the desirable short-chain sodium polysulfides during the practical battery test. These finding indicates that the atomic manganese sites have an enhanced ability to capture and donate electrons. Additionally, the charge transfer process facilitates the rearrangement of sodium ions, thereby accelerating the kinetics of the sodium ions through the electrostatic force. These combined effects improve pathway selectivity and conversion to stable products during the redox process, leading to superior electrochemical performance for room temperature sodium-sulfur batteries.

Solvent-Free Reaction for Unsymmetrical Organodisulfides with High Purity and Application as Cathode-Active Materials.

Unsymmetrical disulfides, in which different organic groups are bonded to disulfide bonds, have been synthesized by cross-coupling reactions using thiols as substrates. However, due to the low-binding energy of unsymmetrical disulfides, its disproportionation occurs based on the side reactions with nucleophilic thiols, resulting in the impurity of symmetric disulfides. In this study, we developed a solvent-free synthesis method for unsymmetrical disulfides using thiosulfonates, thiols, and a base. This synthetic method enabled us to obtain highly pure diaryl-substituted unsymmetrical disulfides with particularly low-binding energy without control over the nucleophilicity and elimination properties of the substrate. Furthermore, it was observed that the disproportionation of unsymmetrical disulfides occurred in the solvent. This means that solvent-free condition is one of the factors to obtain unsymmetrical disulfides. As a new application of unsymmetrical disulfides, we applied unsymmetrical disulfides to cathode active materials of lithium batteries based on the reversible multi-electron redox activity of S-S bonds. The batteries using unsymmetrical disulfide cathode-active materials with a carbon nanotube exhibited initial capacities of 127 and 158 Ah/kg, equal to 42 and 53% of their theoretical ones. We demonstrated that unsymmetrical disulfides could be used as cathode-active materials for rechargeable batteries.

Polymorphism of Two-Dimensional Semiconducting Coordination Polymers: Impact of a Lead-Sulfur Network on Photoconductivity.

Sulfur-coordinated coordination polymers (S-CPs) have unique optoelectrical properties that originate from infinite M-S bond networks. In this study, we synthesized and characterized two polymorphs of a two-dimensional (2D) Pb(II) S-CP with a formula of [Pb(tzdt)(OAc)] (Htzdt=1,3-thiazolidine-2-thione, OAc=acetate). Our findings revealed that the thermodynamic product (KGF-26) possesses quasi-2D (-Pb-S-)n layers with weak nonbonded Pb-S bonds, whereas the kinetic product (KGF-27) has intrinsic 2D (-Pb-S-)n layers with Pb-S bonds. The results of time-resolved microwave conductivity measurements and first-principles calculations confirmed that KGF-27 exhibits higher photoconductivity than KGF-26, which establishes that the inorganic (-Pb-S-)n networks with Pb-S bonds are crucial for achieving high photoconductivity. This is the first experimental demonstration of the impact of the (-M-S-)n networks in S-CPs on photoconductivity through the comparison of crystal polymorphisms.

Stability Modification of Dye-sensitized Solar Cells by Ruthenium Dyes Embedded on Eggshell Membranes.

Dye-sensitized solar cells (DSSCs) have been one of the most promising technologies to convert sunlight into electricity repeatedly based on the mechanism that dyes inject/accept electron into the metal oxides/from redox mediator. Specifically, N719 ([RuL2(NCS)2], L: 4,4'-dicarboxy-2,2'-bipyridine), immobilized on TiO2 through the interaction between its ligands (-COO- and -NCS) and the oxygen on the TiO2 surface, has been used as a conventional DSSC dye with high voltage. Nevertheless, -NCS ligands have been removed from Ru2+ in N719 due to UV irradiation and exchanged with H2O or OH- in electrolyte, resulting in voltage drop. In this work, we developed the first DSSC using the N719-adsorbed Eggshell (ESM)-TiO2 composite to maintain the immobilization of N719 on TiO2 through electrostatic interaction between the protein of ESM and N719. The DSSC using the composite maintained the voltage even after 12 h light irradiation, although the voltage of DSSC without ESM dropped drastically. It means that the ESM contributed to stable photovoltaic performances of DSSCs through the protection of NCS ligands of N719.

yaaJ, the tRNA-Specific Adenosine Deaminase, Is Dispensable in Bacillus subtilis.

Post-transcriptional modifications of tRNA are crucial for their core function. The inosine (I; 6-deaminated adenosine) at the first position in the anticodon of tRNAArg(ICG) modulates the decoding capability and is generally considered essential for reading CGU, CGC, and CGA codons in eubacteria. We report here that the Bacillus subtilis yaaJ gene encodes tRNA-specific adenosine deaminase and is non-essential for viability. A ß-galactosidase reporter assay revealed that the translational activity of CGN codons was not impaired in the yaaJ-deletion mutant. Furthermore, tRNAArg(CCG) responsible for decoding the CGG codon was dispensable, even in the presence or absence of yaaJ. These results strongly suggest that tRNAArg with either the anticodon ICG or ACG has an intrinsic ability to recognize all four CGN codons, providing a fundamental concept of non-canonical wobbling mediated by adenosine and inosine nucleotides in the anticodon. This is the first example of the four-way wobbling by inosine nucleotide in bacterial cells. On the other hand, the absence of inosine modification induced +1 frameshifting, especially at the CGA codon. Additionally, the yaaJ deletion affected growth and competency. Therefore, the inosine modification is beneficial for translational fidelity and proper growth-phase control, and that is why yaaJ has been actually conserved in B. subtilis.

Assessment of Dye-Absorbed Eggshell Membrane Composites as Solid Polymer Electrolyte of Fuel Cells.

Recently, polymer electrolytes have been developed for high-performance and eco-friendly fuel cells. Among the candidates, eggshell membrane (ESM) has been promising because of its abundance to assemble various energy devices with low cost and its absorption ability of organic materials. In this work, we investigated fuel cells that included ESM-absorbing xanthene-, triphenylmethane-, and azo-type tar dye, which contained abundant hydrophilic groups, as polymer electrolytes. We found out two points: (1) that the fuel cells that included ESM-absorbing xanthene-type dye generated the highest I-V performance, and (2) the basic molecular structures of the tar dyes determined the correlation of the maximum power and proton conductivities.

Ultra-High-Capacity Lithium Metal Batteries Based on Multi-Electron Redox Reaction of Organopolysulfides including Conductive Organic Moieties.

Recently, organic polysulfides have been synthesized as cathode active materials exceeding the battery performance of sulfur. However, the conventional organic polysulfides have exhibited capacities lower than the theoretical capacity of sulfur because the π-organic moieties do not conjugate with the sulfur chains. In this work, the organopolysulfides, synthesized via inverse vulcanization using disulfide compounds, exhibited higher capacities equal to the theoretical capacity of sulfur because of enhanced electronic conductivity based on the conjugation between organic moieties and sulfur chains. Furthermore, the organopolysulfide including 1,3-dhitiol-2-thione moiety exhibited the highest capacity because of the enhanced electronic conductivity. This finding will pave the way to develop next-generation rechargeable batteries.

Class II LitR serves as an effector of "short" LOV-type blue-light photoreceptor in Pseudomonas mendocina.

PmlR2, a class II LitR/CarH family transcriptional regulator, and PmSB-LOV, a "short" LOV-type blue light photoreceptor, are adjacently encoded in Pseudomonas mendocina NBRC 14162. An effector protein for the "short" LOV-type photoreceptor in Pseudomonas has not yet been identified. Here, we show that PmlR2 is an effector protein of PmSB-LOV. Transcriptional analyses revealed that the expression of genes located near pmlR2 and its homolog gene, pmlR1, was induced in response to illumination. In vitro DNA-protein binding analyses showed that recombinant PmlR2 directly binds to the promoter region of light-inducible genes. Furthermore PmSB-LOV exhibited a typical LOV-type light-induced spectral change. Gel-filtration chromatography demonstrated that the illuminated PmSB-LOV was directly associated with PmlR2, whereas non-illuminated proteins did not interact. The inhibition of PmlR2 function following PmSB-LOV binding was verified by surface plasmon resonance: the DNA-binding ability of PmlR2 was specifically inhibited in the presence of blue light-illuminated-PmSB-LOV. An In vitro transcription assay showed a dose-dependent reduction in PmlR2 repressor activity in the presence of illuminated PmSB-LOV. Overall, evidence suggests that the DNA-binding activity of PmlR2 is inhibited by its direct association with blue light-activated PmSB-LOV, enabling transcription of light-inducible promoters by RNA polymerase.

Data-driven efficient synthetic exploration of anionic lanthanide-based metal-organic frameworks.

The synthesis of lanthanide metal-organic frameworks with terephthalate (Ln-BDC-MOFs) was investigated using a data-driven approach. Visually mapping the previously reported synthetic conditions suggested the existence of unexplored search spaces for novel Ln-BDC-MOFs. By focusing on the unexplored chemical reaction space, we successfully synthesized a series of new anionic Ln-BDC-MOFs, KGF-15, which demonstrated potential as luminescent sensors for Cu2+ ions. This synthetic exploration approach can significantly reduce the experimental effort required to discover new materials.

Azo Compounds as Active Materials of Energy Storage Systems.

The rapid evolution of electrical devices and the increasing demand for the supply of sustainable energy necessitate the development of high-performance energy storage systems such as rechargeable and redox flow batteries. However, these batteries typically contain inorganic active materials, which exhibit several critical drawbacks hindering further development. In this regard, azo compounds are promising alternatives, offering the benefits of fast kinetics, multi-electron redox reactions, and tunable (via structural adjustment) battery performance. Herein, we review the use of azo compounds as the active materials of rechargeable and redox flow batteries, discuss certain aspects of material design and electrochemical reaction mechanisms, and summarize the corresponding perspectives and research directions to facilitate further progress in this field.

Novel heat shock response mechanism mediated by the initiation nucleotide of transcription.

Among SigA-dependent promoters in Bacillus subtilis, we compared the nucleotide sequences of heat shock responding and non-responding promoters. Chimeric promoter experiments revealed that the heat shock response could be ascribed to the initiation nucleotide (iNTP) of the transcription. Our in vivo reporter assay results indicated that a full response was achieved using GTP, a reduced response was observed using ATP, and no additional expression was observed using UTP or CTP. We then investigated the in vitro transcription assay in more detail. Enhanced transcription that was dependent upon the iNTP was observed when heat treatment was administered during the pre-initiation period. We next analyzed the efficiency of open complex formation using potassium permanganate footprinting, and our results revealed an increase in the ratio of open complex formation at elevated temperatures. Based on this, we suggest that the overall intensification of transcription at high temperatures was derived from the high efficiency of open complex formation together with the high affinity of RNA polymerase (RNAP) for the initiation nucleotide GTP. To determine if this mechanism observed in B. subtilis RNAP is common among bacterial species, we performed similar experiments using Escherichia coli RNAP. Our results indicated that E. coli RNAP also exhibited both temperature- and iNTP-dependent enhancement of transcription. Although the temperature ranges and the ratios of enhancement are somewhat different, the overall heat shock response mechanism mediated by the iNTP of transcription appears to be conserved among bacterial RNAP.

Evolutionary Adaptation by Repetitive Long-Term Cultivation with Gradual Increase in Temperature for Acquiring Multi-Stress Tolerance and High Ethanol Productivity in Kluyveromyces marxianus DMKU 3-1042.

During ethanol fermentation, yeast cells are exposed to various stresses that have negative effects on cell growth, cell survival, and fermentation ability. This study, therefore, aims to develop Kluyveromyces marxianus-adapted strains that are multi-stress tolerant and to increase ethanol production at high temperatures through a novel evolutionary adaptation procedure. K. marxianus DMKU 3-1042 was subjected to repetitive long-term cultivation with gradual increases in temperature (RLCGT), which exposed cells to various stresses, including high temperatures. In each cultivation step, 1% of the previous culture was inoculated into a medium containing 1% yeast extract, 2% peptone, and 2% glucose, and cultivation was performed under a shaking condition. Four adapted strains showed increased tolerance to ethanol, furfural, hydroxymethylfurfural, and vanillin, and they also showed higher production of ethanol in a medium containing 16% glucose at high temperatures. One showed stronger ethanol tolerance. Others had similar phenotypes, including acetic acid tolerance, though genome analysis revealed that they had different mutations. Based on genome and transcriptome analyses, we discuss possible mechanisms of stress tolerance in adapted strains. All adapted strains gained a useful capacity for ethanol fermentation at high temperatures and improved tolerance to multi-stress. This suggests that RLCGT is a simple and efficient procedure for the development of robust strains.

Analysis of cell death in Bacillus subtilis caused by sesquiterpenes from Chrysopogon zizanioides (L.) Roberty.

Recently, the antibacterial effects of essential oils have been investigated in addition to their therapeutic purposes. Owing to their hydrophobic nature, they are thought to perturb the integrity of the bacterial cell membrane, leading to cell death. Against such antibiotic challenges, bacteria develop mechanisms for cell envelope stress responses (CESR). In Bacillus subtilis, a gram-positive sporulating soil bacterium, the extracytoplasmic function (ECF) sigma factor-mediated response system plays a pivotal role in CESR. Among them, σM is strongly involved in response to cell envelope stress, including a shortage of available bactoprenol. Vetiver essential oil, a product of Chrysopogon zizanioides (L.) Roberty root, is also known to possess bactericidal activity. σM was exclusively and strongly induced when the cells were exposed to Vetiver extract, and depletion of multi-ECF sigma factors (ΔsigM, ΔsigW, ΔsigX, and ΔsigV) enhanced sensitivity to it. From this quadruple mutant strain, the suppressor strains, which restored resistance to the bactericidal activity of Vetiver extract, emerged, although attempts to obtain resistant strains from the wild type did not succeed. Whole-genome resequencing of the suppressor strains and genetic analysis revealed inactivation of xseB or pnpA, which code for exodeoxyribonuclease or polynucleotide phosphorylase, respectively. This allowed the quadruple mutant strain to escape from cell death caused by Vetiver extract. Composition analysis suggested that the sesquiterpene, khusimol, might contribute to the bactericidal activity of the Vetiver extract.

Assessment of Eggshell Membrane as a New Type of Proton-Conductive Membrane in Fuel Cells.

Polymer electrolyte membrane fuel cells have recently attracted considerable attention as sustainable and eco-friendly electricity generation devices from the viewpoint of carbon neutrality. This study focuses on new discoveries related to the application of eggshell membranes to polymer electrolytes in the development of cheaper, more eco-friendly fuel cells. We observed the electricity generation of the fuel cells using an eggshell membrane as a proton-conductive material and a general carbonic acid aqueous solution. This new fuel cell will contribute to the continued improvement of available fuel cells at lower costs.

Orthologs of Saccharomyces cerevisiae SFH2, genes encoding Sec14 family proteins, implicated in utilization of n-alkanes and filamentous growth in response to n-alkanes in Yarrowia lipolytica.

The dimorphic yeast Yarrowia lipolytica has an ability to assimilate n-alkanes as carbon and energy sources. In this study, the roles of orthologs of Saccharomyces cerevisiae SEC14 family gene SFH2, which we named SFH21, SFH22, SFH23 and SFH24, of Y. lipolytica were investigated. The transcript levels of SFH21, SFH22 and SFH23, determined by RNA-seq analysis, qRT-PCR analysis and northern blot analysis, were found to increase in the presence of n-alkanes. The deletion mutant of SFH21, but not that of SFH22, SFH23 or SFH24, showed defects in growth in the media containing n-alkanes and in filamentous growth on the solid media containing n-alkanes. Additional deletions of SFH22 and SFH23 significantly exaggerated the defect in filamentous growth of the deletion mutant of SFH21, and expression of SFH22 or SFH24 using the SFH21 promoter partially suppressed the growth defect of the deletion mutant of SFH21 on n-alkanes. These results suggest that SFH2 orthologs are involved in the utilization of n-alkanes and filamentous growth in response to n-alkanes in Y. lipolytica.

Failure-Experiment-Supported Optimization of Poorly Reproducible Synthetic Conditions for Novel Lanthanide Metal-Organic Frameworks with Two-Dimensional Secondary Building Units.

Invited for the cover of this issue are Daisuke Tanaka at Kwansei Gakuin University and co-workers at Kwansei Gakuin University, Hokkaido University, Kyoto University, Japan and KU Leuven, Belgium. The image is a depiction of exploring the desired crystal by decision tree analysis. Read the full text of the article at 10.1002/chem.202102404.

Genome sequencing of the NIES Cyanobacteria collection with a focus on the heterocyst-forming clade.

Cyanobacteria are a diverse group of Gram-negative prokaryotes that perform oxygenic photosynthesis. Cyanobacteria have been used for research on photosynthesis and have attracted attention as a platform for biomaterial/biofuel production. Cyanobacteria are also present in almost all habitats on Earth and have extensive impacts on global ecosystems. Given their biological, economical, and ecological importance, the number of high-quality genome sequences for Cyanobacteria strains is limited. Here, we performed genome sequencing of Cyanobacteria strains in the National Institute for Environmental Studies microbial culture collection in Japan. We sequenced 28 strains that can form a heterocyst, a morphologically distinct cell that is specialized for fixing nitrogen, and 3 non-heterocystous strains. Using Illumina sequencing of paired-end and mate-pair libraries with in silico finishing, we constructed highly contiguous assemblies. We determined the phylogenetic relationship of the sequenced genome assemblies and found potential difficulties in the classification of certain heterocystous clades based on morphological observation. We also revealed a bias on the sequenced strains by the phylogenetic analysis of the 16S rRNA gene including unsequenced strains. Genome sequencing of Cyanobacteria strains deposited in worldwide culture collections will contribute to understanding the enormous genetic and phenotypic diversity within the phylum Cyanobacteria.

Failure-Experiment-Supported Optimization of Poorly Reproducible Synthetic Conditions for Novel Lanthanide Metal-Organic Frameworks with Two-Dimensional Secondary Building Units*.

Novel metal-organic frameworks containing lanthanide double-layer-based secondary building units (KGF-3) were synthesized by using machine learning (ML). Isolating pure KGF-3 was challenging, and the synthesis was not reproducible because impurity phases were frequently obtained under the same synthetic conditions. Thus, dominant factors for the synthesis of KGF-3 were identified, and its synthetic conditions were optimized by using two ML techniques. Cluster analysis was used to classify the obtained powder X-ray diffractometry patterns of the products and thus automatically determine whether the experiments were successful. Decision-tree analysis was used to visualize the experimental results, after extracting factors that mainly affected the synthetic reproducibility. Water-adsorption isotherms revealed that KGF-3 possesses unique hydrophilic pores. Impedance measurements demonstrated good proton conductivities (σ=5.2×10-4  S cm-1 for KGF-3(Y)) at a high temperature (363 K) and relative humidity of 95 % RH.

Application of µ-Nitrido- and µ-Carbido-Bridged Iron Phthalocyanine Dimers as Cathode-Active Materials for Rechargeable Batteries.

µ-Nitrido- and µ-carbido-bridged iron phthalocyanine dimers, when used as cathode-active materials for rechargeable lithium batteries, showed four stable redox waves in cyclic voltammetry studies in solution and a stable discharge capacity of approximately 60 mAh g-1 after 200 cycles. These results indicate that µ-heteroatom-bridged iron phthalocyanine dimers are good platforms for designing novel phthalocyanine-based electrode-active materials.