Directional Migration and Rapid Coalescence of Au Nanoparticles on Anisotropic ReS2.

Interfacial atomic configuration and its evolution play critical roles in the structural stability and functionality of mixed zero-dimensional (0D) metal nanoparticles (NPs) and two-dimensional (2D) semiconductors. In situ observation of the interface evolution at atomic resolution is a vital method. Herein, the directional migration and structural evolution of Au NPs on anisotropic ReS2 were investigated in situ by aberration-corrected transmission electron microscopy. Statistically, the migration of Au NPs with diameters below 3 nm on ReS2 takes priority with greater probability along the b-axis direction. Density functional theory calculations suggest that the lower diffusion energy barrier enables the directional migration. The coalescence kinetics of Au NPs is quantitatively described by the relation of neck radius (r) and time (t), expressed as r2=Kt. Our work provides an atomic-resolved dynamic analysis method to study the interfacial structural evolution of metal/2D materials, which is essential to the study of the stability of nanodevices based on mixed-dimensional nanomaterials.

Understanding the interaction of nucleotides with UVC light: an insight from quantum chemical calculation-based findings.

Short-wave ultraviolet (also called UVC) irradiation is a well-adopted method of viral inactivation due to its ability to damage genetic material. A fundamental problem with the UVC inactivation method is that its mechanism of action on viruses is still unknown at the molecular level. To address this problem, herein we investigate the response mechanism of genome materials to UVC light by means of quantum chemical calculations. The spectral properties of four nucleotides, namely, adenine, cytosine, guanine, and uracil, are mainly focused on. Meanwhile, the transition state and reaction rate constant of uracil molecules are also considered to demonstrate the difficulty level of adjacent nucleotide reaction without and with UVC irradiation. The results show that the peak wavelengths are 248.7 nm, 226.1 nm (252.7 nm), 248.3 nm, and 205.8 nm (249.2 nm) for adenine, cytosine, guanine, and uracil nucleotides, respectively. Besides, the reaction rate constants of uracil molecules are 6.419 × 10-49 s-1 M-1 and 5.436 × 1011 s-1 M-1 for the ground state and excited state, respectively. Their corresponding half-life values are 1.56 × 1048 s and 1.84 × 10-12 s. This directly suggests that the molecular reaction between nucleotides is a photochemical process and the reaction without UVC irradiation almost cannot occur.

Bi2[B2(SeO3)6]: A Metal Boroselenite with a Unique Zero-Dimensional [B2(SeO3)6]6- Anionic Group and Large Birefringence.

Explorations of new types of borates are important because of their promising application in diverse fields. A new bismuth-containing boroselenite, Bi2[B2(SeO3)6], has been obtained through high-temperature solid-state reaction in a closed system. Bi2[B2(SeO3)6] possesses a zero-dimensional [B2(SeO3)6]6- anionic group that does not belong to any types of reported boroselenites. Besides, Bi2[B2(SeO3)6] is the first boroselenite with lone-pair electrons containing a metal ion as the countercation. More interestingly, on the basis of the first-principles calculations, this compound displays a large birefringence (0.090) at 1064 nm.

OsMADS32 interacts with PI-like proteins and regulates rice flower development.

OsMADS32 is a monocot specific MIKC(c) type MADS-box gene that plays an important role in regulating rice floral meristem and organs identity, a crucial process for reproductive success and rice yield. However, its underlying mechanism of action remains to be clarified. Here, we characterized a hypomorphic mutant allele of OsMADS32/CFO1, cfo1-3 and identified its function in controlling rice flower development by bioinformatics and protein-protein interaction analysis. The cfo1-3 mutant produces defective flowers, including loss of lodicule identity, formation of ectopic lodicule or hull-like organs and decreased stamen number, mimicking phenotypes related to the mutation of B class genes. Molecular characterization indicated that mis-splicing of OsMADS32 transcripts in the cfo1-3 mutant resulted in an extra eight amino acids in the K-domain of OsMADS32 protein. By yeast two hybrid and bimolecular fluorescence complementation assays, we revealed that the insertion of eight amino acids or deletion of the internal region in the K1 subdomain of OsMADS32 affects the interaction between OsMADS32 with PISTILLATA (PI)-like proteins OsMADS2 and OsMADS4. This work provides new insight into the mechanism by which OsMADS32 regulates rice lodicule and stamen identity, by interaction with two PI-like proteins via its K domain.

Real-time Observation of Deep Lithiation of Tungsten Oxide Nanowires by In†Situ Electron Microscopy.

An in-depth mechanistic understanding of the electrochemical lithiation process of tungsten oxide (WO3 ) is both of fundamental interest and relevant for potential applications. One of the most important features of WO3 lithiation is the formation of the chemically flexible, nonstoichiometric Lix WO3 , known as tungsten bronze. Herein, we achieved the real-time observation of the deep electrochemical lithiation process of single-crystal WO3 nanowires by constructing in situ transmission electron microscopy (TEM) electrochemical cells. As revealed by nanoscale imaging, diffraction, and spectroscopy, it is shown that the rapid and deep lithiation of WO3 nanowires leads to the formation of highly disordered and near-amorphous Lix WO3 phases, but with no detectable traces of elemental W and segregated Li2 O phase formation. These results highlight the remarkable chemical and structural flexibility of the Lix WO3 phases in accommodating the rapid and deep lithiation reaction.

Chitosan Oligosaccharide Laser Lithograph: A Facile Route to Porous Graphene Electrodes for Flexible On-Chip Microsupercapacitors.

In this study, a convenient chitosan oligosaccharide laser lithograph (COSLL) technology was developed to fabricate laser-induced graphene (LIG) electrodes and flexible on-chip microsupercapacitors (MSCs). With a simple one-step CO2 laser, the pyrolysis of a chitosan oligosaccharide (COS) and in situ welding of the generated LIGs to engineering plastic substrates are achieved simultaneously. The resulting LIG products display a hierarchical porous architecture, excellent electrical conductivity (6.3 Ω sq-1), and superhydrophilic properties, making them ideal electrode materials for MSCs. The pyrolysis-welding coupled mechanism is deeply discussed through cross-sectional analyses and finite element simulations. The MSCs prepared by COSLL exhibit considerable areal capacitance of over 4 mF cm-2, which is comparable to that of the polyimide-LIG-based counterpart. COSLL is also compatible with complementary metal-oxide-semiconductor (CMOS) and micro-electro-mechanical system (MEMS) processes, enabling the fabrication of LIG/Au MSCs with comparable areal capacitance and lower internal resistance. Furthermore, the as-prepared MSCs demonstrate excellent mechanical robustness, long-cycle capability, and ease of series-parallel integration, benefiting their practical application in various scenarios. With the use of eco-friendly biomass carbon source and convenient process flowchart, the COSLL emerges as an attractive method for the fabrication of flexible LIG on-chip MSCs and various other advanced LIG devices.

Proteomics-Guided Mining and Characterization of Epoxidase Involved in Camptothecin Biosynthesis from Camptotheca acuminata.

The detailed metabolic map for camptothecin (CPT) biosynthesis in Camptotheca acuminata has been proposed according to our combined omics results. However, the CYP450-mediated epoxidation step in CPT biosynthesis remains unexplored. A proteomics-guided approach was used to identify and annotate the proteins enriched during the vigorous CPT metabolism period in mature C. acuminata and seedlings. Comparative analyses revealed that the CPT and flavonoid biosyntheses were vigorous in stems and all of the samples except the leaves, respectively. The CYP71BE genes were screened based on their enrichment patterns at the transcriptomic-proteomic level and biochemically characterized in Saccharomyces cerevisiae WAT11. Four CYP71BE proteins exhibited in vitro isoliquiritigenin epoxidase activity. Additionally, CYP71BE206 showed epoxidase activity toward strictosamide, the critical precursor for CPT biosynthesis, both in vitro and in Nicotiana benthamiana. In planta functional verification suggested that CYP71BE206 is involved in CPT biosynthesis. Their catalytic conditions were optimized, and the enzymatic parameters were determined. This study provides valuable insight into the CYP71BE-mediated epoxidation step for CPT biosynthesis and offers evidence to verify that the newly characterized epoxidase (CYP71BE206) is simultaneously responsible for the biosynthesis of CPT and the flavonoid in this plant. An evolution event probably happened on ancestral CYP71BE, resulting in the neofunctionalization of CYP71BE206.

Rapid Fabrication of High-Performance Flexible Pressure Sensors Using Laser Pyrolysis Direct Writing.

The fabrication of flexible pressure sensors with low cost, high scalability, and easy fabrication is an essential driving force in developing flexible electronics, especially for high-performance sensors that require precise surface microstructures. However, optimizing complex fabrication processes and expensive microfabrication methods remains a significant challenge. In this study, we introduce a laser pyrolysis direct writing technology that enables rapid and efficient fabrication of high-performance flexible pressure sensors with a micro-truncated pyramid array. The pressure sensor demonstrates exceptional sensitivities, with the values of 3132.0, 322.5, and 27.8 kPa-1 in the pressure ranges of 0-0.5, 0.5-3.5, and 3.5-10 kPa, respectively. Furthermore, the sensor exhibits rapid response times (loading: 22 ms, unloading: 18 ms) and exceptional reliability, enduring over 3000 pressure loading and unloading cycles. Moreover, the pressure sensor can be easily integrated into a sensor array for spatial pressure distribution detection. The laser pyrolysis direct writing technology introduced in this study presents a highly efficient and promising approach to designing and fabricating high-performance flexible pressure sensors utilizing micro-structured polymer substrates.

Discovery of unique CYP716C oxidase involved in pentacyclic triterpene biosynthesis from Camptotheca acuminata.

Dozens of triterpenes have been isolated from Camptotheca acuminata, however, triterpene metabolism in this plant remains poorly understood. The common C28 carboxy located in the oleanane-type and ursane-type triterpenes indicates the existence of a functionally active triterpene, C28 oxidase, in this plant. Thorough mining and screening of the CYP716 genes were initiated using the multi-omics database for C. acuminata. Two CYP716A (CYP716A394 and CYP716A395) and three CYP716C (CYP716C80-CYP716C82) were identified based on conserved domain analyses and hierarchical cluster analyses. CYP716 microsomal proteins were prepared and their enzymatic activities were evaluated in vitro. The CYP716 classified into the CYP716C subfamily displays ß-amyrin oxidation activity, and CYP716A displays α-amyrin and lupeol oxidation activity, based on gas chromatography-mass spectrometry analyses. The oxidation products were determined based on their mass and nuclear magnetic resonance spectrums. The optimum reaction conditions and kinetic parameters for CYP716C were determined, and functions were verified in Nicotiana benthaminana. Relative quantitative analyses revealed that these CYP716C genes were enriched in the leaves of C. acuminata plantlets after 60 d. These results indicate that CYP716C plays a dominant role in oleanane-type triterpene metabolism in the leaves of C. acuminata via a substrate-specific manner, and CYP716A is responsible for ursane- and lupane-type triterpene metabolism in fruit. This study provides valuable insights into the unique CYP716C-mediated oxidation step of pentacyclic triterpene biosynthesis in C. acuminata.

Hydrogenated Boron Phosphide THz-Metamaterial-Based Biosensor for Diagnosing COVID-19: A DFT Coupled FEM Study.

Recent reports focus on the hydrogenation engineering of monolayer boron phosphide and simultaneously explore its promising applications in nanoelectronics. Coupling density functional theory and finite element method, we investigate the bowtie triangle ring microstructure composed of boron phosphide with hydrogenation based on structural and performance analysis. We determine the carrier mobility of hydrogenated boron phosphide, reveal the effect of structural and material parameters on resonance frequencies, and discuss the variation of the electric field at the two tips. The results suggest that the mobilities of electrons for hydrogenated BP monolayer in the armchair and zigzag directions are 0.51 and 94.4 cm2·V-1·s-1, whereas for holes, the values are 136.8 and 175.15 cm2·V-1·s-1. Meanwhile, the transmission spectra of the bowtie triangle ring microstructure can be controlled by adjusting the length of the bowtie triangle ring microstructure and carrier density of hydrogenated BP. With the increasing length, the transmission spectrum has a red-shift and the electric field at the tips of equilateral triangle rings is significantly weakened. Furthermore, the theoretical sensitivity of the BTR structure reaches 100 GHz/RIU, which is sufficient to determine healthy and COVID-19-infected individuals. Our findings may open up new avenues for promising applications in the rapid diagnosis of COVID-19.

Structure-based identification and pathway elucidation of flavonoids in Camptotheca acuminate.

Flavonoid metabolism in Camptotheca acuminate remained an untapped area for years. A tandem MS approach was used and focused on the mining and characterizing of flavonoids in mature C. acuminate. Fifteen new flavonoids and forty-three known flavonoids, including fifteen flavone analogs, sixteen flavonol analogs, seven flavanone analogs, six chalcone analogs, four xanthone analogs, ten flavane analogs were mined and identified based on their MS/MS fragments. Fifty-three of them were firstly characterized in C. acuminate. Eight biosynthetic precursors for these flavonoids were also identified. We constructed a specific metabolic map for flavonoids according to their relative contents in the flowers, fruits, stems, and leaves of C. acuminate. Furthermore, the most probable genes involved in chalcone biosynthesis, flavonoid hydroxylation, methylation, and glycosylation were further mined and fished in the gene reservoir of C. acuminate according to their conserved domains and co-expression analysis. These findings enable us to acquire a better understanding of versatile flavonoid metabolism in C. acuminate.

Integrative Analysis of Elicitor-Induced Camptothecin Biosynthesis in Camptotheca acuminata Plantlets Through a Combined Omics Approach.

Treatments with abiotic elicitors can efficiently induce the accumulation of specialized metabolites in plants. We used a combined omics approach to analyze the elicitation effects of MeJa, AgNO3, and PEG on camptothecin (CPT) biosynthesis in Camptotheca acuminata plantlets. Untargeted analyses revealed that treatments with MeJa, AgNO3, and PEG significantly inhibited the photosynthetic pathway and promoted carbon metabolism and secondary metabolic pathways. The CPT levels increased by 78.6, 73.3, and 50.0% in the MeJa, AgNO3, and PEG treatment groups, respectively. Using C. acuminata plantlets after elicitation treatment, we mined and characterized 15 new alkaloids, 25 known CPT analogs and precursors, 9 iridoid biosynthetic precursors, and 15 tryptamine biosynthetic precursors based on their MS/MS fragmentation spectra. Using 32 characterized genes involved in CPT biosynthesis as bait, we mined 12 prioritized CYP450 genes from the 416 CYP450 candidates that had been identified based on co-expression analysis, conserved domain analysis, and their elicitation-associated upregulation patterns. This study provides a comprehensive perspective on CPT biosynthesis in C. acuminata plantlets after abiotic elicitation. The findings enable us to elucidate the previously unexplored CYP450-mediated oxidation steps for CPT biosynthesis.

Temperature-dependent selective purification of plasmid DNA using magnetic nanoparticles in an RNase-free process.

Carboxyl group-functionalized magnetic nanoparticles were used to develop an RNase-free method for plasmid DNA (pDNA) purification directly from RNA-containing crude Escherichia coli lysates. This method takes advantage of differing adsorption behaviors of pDNA and RNA onto magnetic nanoparticle surfaces at different temperatures. Pure pDNA can be isolated between 70 and 80°C without sacrificing DNA quality and quantity, as evidenced by comparison with that obtained using organic solvents or commercial kits. This RNase-free method is rapid, simple, cost-effective, and environmentally friendly, and it can be easily scaled up for the production of pharmacological-grade pDNA.

Ganodermasides C and D, two new anti-aging ergosterols from spores of the medicinal mushroom Ganoderma lucidum.

Two new anti-aging compounds, ganodermasides C and D, were isolated and their structures elucidated. They are novel ergosterols possessing a 4,6,8(14),22-tetraene-3-one unit with unique hydroxylation at C-9. Both of them significantly extended the replicative lifespan of the K6001 yeast strain. Ganodermasides C and D regulated the expression of the gene for UTH1 to prolong the replicative lifespan of yeast.

New neuritogenic steroidal saponin from Ophiopogon japonicus (Thunb.) Ker-Gawl.

A new steroidal saponin was isolated from Ophiopogon japonicus. This saponin possesses a modification by 2-hydroxy-3-methylvalerylation of the hydroxyl group at C-4' of the sugar, linked to C-1 of the aglycone. It exhibited significant neuritogenic activity for PC12 cells. The structure-activity relationship revealed the aglycone, rather than the sugar moieties and acylation, to be important for the neuritogenic activity.

[A neuritogenic compound from Tremella fuciformis].

OBJECTIVE: To search for low-molecular-weight neuritogenic compounds from the traditional Chinese medicine (TCM). METHOD: An extract library of TCM was prepared. Targeted isolation guided by biological screening led to the discovery of compound 1, and its structure was elucidated by analysis of spectroscopic methods and comparison of spectroscopic data with these reported from the literature. RESULT: A neuritogenic compound 1, 3-O-beta-D-glucopyranosyl-22E, 24R-5alpha, 8alpha-epidioxyergosta-6, 22-diene, was isolated and identified from the methanol extract of T. fuciformis. This compound showed a significant neuritogenic activity against PC12 cells at 3 micromol x L(-1)). CONCLUSION: Methonal extract of T. fuciformis and targeted compound 1 both showed significant neuritogenic activity against PC12 cells. These results suggested that the extract and compound 1 might be used to prevent and treat neurodegenerative disease such as Alzheimer's disease.

Ba2[FeF4(IO3)2]IO3: a promising nonlinear optical material achieved by chemical-tailoring-induced structure evolution.

A new noncentrosymmetric iron-iodate-fluoride Ba2[FeF4(IO3)2]IO3 was ingeniously obtained based on the centrosymmetric Ba[FeF4(IO3)] through chemical tailoring. Ba2[FeF4(IO3)2]IO3 exhibits a strong phase-matchable second-harmonic generation effect, a large band gap, and a wide mid-infrared transparent window. The chemical tailoring design based on oxide-fluoride anions affords a feasible approach to design nonlinear optical materials.

[GaF(H2O)][IO3F]: a promising NLO material obtained by anisotropic polycation substitution.

A novel salt-inclusion fluoroiodate [GaF(H2O)][IO3F] derived from CsIO2F2 was ingeniously obtained through anisotropic polycation substitution. Because the catenulate [GaF(H2O)]2+ framework serves as a template for the favorable assembly of the polar [IO3F]2- groups and contributes to the nonlinear coefficient, [GaF(H2O)][IO3F] exhibits a greatly improved second-harmonic generation (SHG) effect of 10 times that of KH2PO4 (KDP) and a considerable band gap of 4.34 eV compared to the parent compound CsIO2F2 (3 × KDP, 4.5 eV). Particularly, to the best of our knowledge, [GaF(H2O)][IO3F] has the largest laser-induced damage threshold (LDT) of 140 × AgGgS2 of the reported iodates. All these results signify that [GaF(H2O)][IO3F] is a promising nonlinear optical (NLO) crystal. This work also proposes that anisotropic polycation substitution is an effective approach to optimize the SHG effect and develop excellent NLO materials.

Bacteria capture, lysate clearance, and plasmid DNA extraction using pH-sensitive multifunctional magnetic nanoparticles.

A multifunctional magnetic nanoparticle (MNP)-assisted bioseparation method was developed to isolate plasmid DNA (pDNA) from Escherichia coli culture. Using the pH-sensitive carboxyl-modified magnetic nanoparticles, both cell capture and the subsequent removal of genomic DNA/protein complex after lysis can be achieved simply by magnetic separation. Furthermore, the yield and purity of pDNA extracted by MNPs are comparable to those obtained using organic solvents or commercial kits. This time- and cost-effective protocol does not require centrifugation or precipitation steps and has the potential for automated DNA extraction, especially within miniaturized lab chip applications.

Ganodermasides A and B, two novel anti-aging ergosterols from spores of a medicinal mushroom Ganoderma lucidum on yeast via UTH1 gene.

Two novel ergosterol derivatives, ganodermasides A and B, hydroxylated at C-15 were isolated from the methanol extract of spores of a medicinal mushroom, Ganoderma lucidum, showed to extend the replicative life span of Saccharomyces cerevisiae, a yeast of K6001 strain. The stereostructures of ganodermasides A and B were determined based on the spectroscopic analysis and comparison of spectroscopic data. These new sterols have a 4, 6, 8(14), 22-tetraene-3-one unit with a unique hydroxylation at C-15. The anti-aging activity of these compounds on yeast is comparable to a well-known substance, resveratrol. Based on results of the investigation of the mechanism of biological activity, ganodermasides A and B regulated UTH1 expression in order to extend the replicative life span of yeast.