Acyl carrier protein OsMTACP2 confers rice cold tolerance at the booting stage.

Low temperatures occurring at the booting stage in rice (Oryza sativa L.) often result in yield loss by impeding male reproductive development. However, the underlying mechanisms by which rice responds to cold at this stage remain largely unknown. Here, we identified MITOCHONDRIAL ACYL CARRIER PROTEIN 2 (OsMTACP2), the encoded protein of which mediates lipid metabolism involved in the cold response at the booting stage. Loss of OsMTACP2 function compromised cold tolerance, hindering anther cuticle and pollen wall development, resulting in abnormal anther morphology, lower pollen fertility, and seed setting. OsMTACP2 was highly expressed in tapetal cells and microspores during anther development, with the encoded protein localizing to both mitochondria and the cytoplasm. Comparative transcriptomic analysis revealed differential expression of genes related to lipid metabolism between the wild type and the Osmtacp2-1 mutant in response to cold. Through a lipidomic analysis, we demonstrated that wax esters, which are the primary lipid components of the anther cuticle and pollen walls, function as cold-responsive lipids. Their levels increased dramatically in the wild type but not in Osmtacp2-1 when exposed to cold. Additionally, mutants of two cold-induced genes of wax ester biosynthesis, ECERIFERUM1 and WAX CRYSTAL-SPARSE LEAF2, showed decreased cold tolerance. These results suggest that OsMTACP2-mediated wax ester biosynthesis is essential for cold tolerance in rice at the booting stage.

Signal Modulation Induced by a Hole Transfer Layer Participant Photoactive Gate: A Highly Sensitive Organic Photoelectrochemical Transistor Sensing Platform.

It is urgent to pursue appropriate gate photoactive materials for gate-to-channel signal modulation to achieve superior transconductance performances of organic photoelectrochemical transistor (OPECT) sensors. Notably, a hole transfer layer (HTL) participant CdZnS/sulfur-doped Ti3C2 MXene (S-MXene) gate was designed and developed in this work, which exhibited a remarkable signal modulation performance by up to 3 orders of magnitude. Because of the incorporation of S-MXene with an enhanced electrical conductivity as the effective HTL, the signal modulation capabilities of the CdZnS/S-MXene photoactive gate were superior to those of CdZnS and CdZnS/MXene. This incorporation inhibited the recombination of the interfacial charge and facilitated the transfer of photogenerated holes, thus enhancing the photoelectric conversion performance. This enhancement facilitated fast electron transfer with a larger effective photovoltage to augment the dedoping ability of channel ions. Based on these findings, an aptasensing platform that exhibited good performance was constructed using the proposed OPECT device, with ofloxacin as a model target and an aptamer for specific recognition. The developed OPECT aptasensor had various advantages, including a high sensitivity, good linear range (1.0 × 10-13 to 1.0 × 10-6 M), and low limit of detection (3.3 × 10-15 M). This study provided a proof-of-concept for the generalized development of HTL participant gates for OPECT sensors and other related applications.

DEAD-BOX RNA HELICASE 27 regulates microRNA biogenesis, zygote division, and stem cell homeostasis.

After double fertilization, zygotic embryogenesis initiates a new life cycle, and stem cell homeostasis in the shoot apical meristem (SAM) and root apical meristem (RAM) allows plants to produce new tissues and organs continuously. Here, we report that mutations in DEAD-BOX RNA HELICASE 27 (RH27) affect zygote division and stem cell homeostasis in Arabidopsis (Arabidopsis thaliana). The strong mutant allele rh27-1 caused a zygote-lethal phenotype, while the weak mutant allele rh27-2 led to minor defects in embryogenesis and severely compromised stem cell homeostasis in the SAM and RAM. RH27 is expressed in embryos from the zygote stage, and in both the SAM and RAM, and RH27 is a nucleus-localized protein. The expression levels of genes related to stem cell homeostasis were elevated in rh27-2 plants, alongside down-regulation of their regulatory microRNAs (miRNAs). Further analyses of rh27-2 plants revealed reduced levels of a large subset of miRNAs and their pri-miRNAs in shoot apices and root tips. In addition, biochemical studies showed that RH27 associates with pri-miRNAs and interacts with miRNA-biogenesis components, including DAWDLE, HYPONASTIC LEAVES 1, and SERRATE. Therefore, we propose that RH27 is a component of the microprocessor complex and is critical for zygote division and stem cell homeostasis.

Synergistic Signal Amplification-Initiated Innovative Self-Powered Photoelectrochemical Aptasensing: An Ingenious Photocathode Activated by the High-Light-Harvesting Photoanode.

Exploiting ingenious photoelectrodes and innovative signal amplification strategies has the potential to achieve high sensitivity in self-powered cathodic photoelectrochemical (PEC) analysis. In this work, a novel self-powered PEC sensing platform was constructed by integrating a synergistic signal amplification of an ingenious photocathode with a high light-harvesting photoanode. In the dual photoelectrode-based PEC system, the amplified photocurrent signals were induced by a synergistic enhancement: (1) the photocurrent of the BiOBr photocathode was improved by the incorporation of nitrogen-doped graphene; (2) the photocurrent of the self-powered sensor was activated by the high-light-harvesting Bi2S3-C3N4 photoanode. Subsequently, the rational mechanism for synergistic signal amplification was investigated. For the construction of the sensing interface, an aptamer was introduced as the recognition element to specifically capture the streptomycin (STR) target. Under optimal conditions, the constructed self-powered aptasensor has the merits of good linear range (1 × 10-11 to 5 × 10-7 M), acceptable limit of detection (1.18 × 10-12 M), and excellent stability and selectivity for STR detection. Additionally, the proposed self-powered aptasensor showed acceptable accuracy for the detection of STR in water. Hopefully, this might stimulate more interest in designing and constructing novel platforms for exquisite photocathodic monitoring of various contaminants in the environment.

Signal Modulation of Organic Photoelectrochemical Transistor by a Z-Scheme Photocathodic Gate: An Innovative Dual Amplification Strategy for Sensitive Aptasensing Application.

Pursuing a more efficient signal amplification strategy is highly demanded for improving the performance of the promising cathodic photoelectrochemical (PEC) sensors. In this work, we present an extremely effective dual signal amplification strategy by the integration of a Z-scheme nanohybrids-based photocathode with the effective signal modulation of an organic photoelectrochemical transistor (OPECT) device. Specifically, photocathodic gate material of CdTe-BiOBr nanohybrids with a Z-scheme electron-transfer route was designed and synthesized for preliminary improvement of the activity of the photogate; afterward, signal modulation of the OPECT system by the photocathodic gate of CdTe-BiOBr was then accomplished for further signal amplification by 2 orders of magnitude. As a result, the output PEC signal of CdTe-BiOBr was enhanced by 17.5-fold as compared to BiOBr, and the channel current (IDS) of the OPECT device was 117-fold magnified than its gate current (IG) response. Exemplified by tetracycline (TC) as a model target and aptamer as the specific recognition element, a versatile cathodic aptasensing platform was constructed based on the proposed OPECT device. The introduced OPECT aptasensor merits advantages, including a good linear range (1.0 × 10-12 to 1.0 × 10-6 M), a low limit of detection (4.2 × 10-13 M), and superior sensitivity than the traditional PEC methods for TC detection, which represents a universal protocol for developing the innovative photocathodic OPECT sensing platform toward accurate analysis.

Streptomyces plumbidurans sp. nov., a Pb2+-tolerant actinomycete.

A novel actinobacterium, designated KC 17012T, was isolated from lead zinc tailings collected from Lanping, Yunnan, PR China. Comparative 16S rRNA gene sequencing showed that KC 17012T belonged to the genus Streptomyces and was most closely related to the type strains of Streptomyces neyagawaensis (98.34%), Streptomyces panaciradicis (98.34%) and Streptomyces heilongjiangensis (98.27%). Phylogenetic tree analysis revealed strain KC 17012T formed a distinct clade. The genome size was 8.64 Mbp with a DNA G+C content of 70.8%. Digital DNA-DNA hybridization and average nucleotide identity values between the genome sequence of strain KC 17012T and those of S. neyagawaensis JCM 4796T (25.3 and 81.5 %) and S. panaciradicis NBRC 109811T (30.1 and 85.7 %) were below the thresholds of 70 and 96% for prokaryotic conspecific assignation. The strain formed long straight aerial hyphae which generated regular short rod spores with spiny surfaces. Growth occurred at 10-45 °C, pH 6-8 and with 0-9 % NaCl (w/v). Strain KC 17012T contained ll-diaminopimelic acid and the major whole-cell hydrolysates included glucose, mannose and ribose. The menaquinones were MK-9(H4), MK-9(H6) and MK-9(H8). The major cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, one unidentified lipid and one unidentified phospholipid. On the basis of the results of a polyphasic taxonomic study, it is concluded that KC 17012T represents a novel species of the genus Streptomyces, for which the name Streptomyces plumbidurans sp. nov., is proposed. The type strain is KC 17012T (CGMCC 4.7704T=JCM 35204T).

Siccirubricoccus soli sp. nov., a novel bacterial species isolated from Jiaozi Mountain soil.

An isolate of Gram-stain-negative and strictly aerobic bacterium, designated KC 17139T, was isolated from Jiaozi Mountain sample in Yunnan, China. Cells were non-motile cocci to oval, catalase-positive and oxidase-positive. Growth occurred at 0-7% NaCl (w/v; optimum, 0%), pH 6.0-8.0 (optimum, pH 7.0) and 15-45 °C (optimum, 28-37 °C). The polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylcholine (PC) and four unidentified aminolipids (UALs). Strain KC 17139T contained summed feature 8 (comprising C18:1 ω7c and/or C18:1 ω6c), C18:1 2OH and C16:0 as major cellular fatty acids (> 5%) and ubiquinone-10 as the sole isoprenoid quinone. The 16S rRNA gene sequence analysis indicated that strain KC 17139T shared highest similarities with Siccirubricoccus phaeus 1-3T (96.7%) and Siccirubricoccus deserti SYSU D8009T (95.0%). Strain KC 17139T clustered with the two Siccirubricoccus type strains, but formed a separate branch in both 16S rRNA gene and genome-scale phylogenetic dendrograms. The genomic DNA G + C content of strain KC 17139T was 71.2%. Genomic comparisons between strain KC 17139T and its close relatives showed the highest digital DNA-DNA hybridisation to S. phaeus (35.5%), highest average nucleotide identity to S. phaeus (88.2%), indicating that strain KC 17139T represents a novel species. On the basis of results of phenotypic, chemotaxonomic and molecular analysis, we report a new bacterium strain KC 17139T belonged to genus Siccirubricoccus, for which the name Siccirubricoccus soli sp. nov. is proposed. The type strain is KC 17139T (= CGMCC 1.18756T = JCM 35132T).

CLE peptides: critical regulators for stem cell maintenance in plants.

MAIN CONCLUSION: Plant CLE peptides, which regulate stem cell maintenance in shoot and root meristems and in vascular bundles through LRR family receptor kinases, are novel, complex, and to some extent conserved. Over the past two decades, peptide ligands of the CLAVATA3 (CLV3) /Embryo Surrounding Region (CLE) family have been recognized as critical short- and long-distance communication signals in plants, especially for stem cell homeostasis, cell fate determination and physiological responses. Stem cells located at the shoot apical meristem (SAM), the root apical meristem (RAM) and the procambium divide and differentiate into specialized cells that form a variety of tissues such as epidermis, ground tissues, xylem and phloem. In the SAM of Arabidopsis (Arabidopsis thaliana), the CLV3 peptide restricts the number of stem cells via leucine-rich repeat (LRR)-type receptor kinases. In the RAM, root-active CLE peptides are critical negative regulators, while ROOT GROWTH FACTOR (RGF) peptides are positive regulators in stem cell maintenance. Among those root-active CLE peptides, CLE25 promotes, while CLE45 inhibits phloem differentiation. In vascular bundles, TRACHEARY ELEMENT DIFFERENTIATION INHIBITORY FACTOR (TDIF)/CLE41/CLE44 promotes procambium cell division, and prevents xylem differentiation. Orthologs of CLV3 have been identified in liverwort (Marchantia polymorpha), tomato (Solanum lycopersicum), rice (Oryza sativa), maize (Zea mays) and lotus (Lotus japonicas), suggesting that CLV3 is an evolutionarily conserved signal in stem cell maintenance. However, functional characterization of endogenous CLE peptides and corresponding receptor kinases, and the downstream signal transduction has been challenging due to their genome-wide redundancies and rapid evolution.

Metal-bipyridine complexes as electrocatalysts for the reduction of CO2: a density functional theory study.

Polypyridyl transition metal complexes are well-established homogeneous electrocatalysts for the reduction of CO2. In this work, the relationship between the transition metal (including V, Cr, Mn, Nb, Mo, Ta, W, and Re) and the catalytic activity has been theoretically investigated using density functional theory. It is found that the transition metal center determines the catalytic activity of M(bpy)(CO)4. Among the eight metal complexes, Re(bpy)(CO)4 and Mn(bpy)(CO)4 exhibit better catalytic activity due to the weaker adsorption strength of CO and lower d-band center, which makes it easier to activate the metal complex and results in a lower reaction free energy of the rate-determining step at the reduction potential. We believe that these results can provide guidelines for the design of novel electrocatalysts for CO2 reduction.

ZYGOTE-ARREST 3 that encodes the tRNA ligase is essential for zygote division in Arabidopsis.

In sexual organisms, division of the zygote initiates a new life cycle. Although several genes involved in zygote division are known in plants, how the zygote is activated to start embryogenesis has remained elusive. Here, we showed that a mutation in ZYGOTE-ARREST 3 (ZYG3) in Arabidopsis led to a tight zygote-lethal phenotype. Map-based cloning revealed that ZYG3 encodes the transfer RNA (tRNA) ligase AtRNL, which is a single-copy gene in the Arabidopsis genome. Expression analyses showed that AtRNL is expressed throughout zygotic embryogenesis, and in meristematic tissues. Using pAtRNL::cAtRNL-sYFP-complemented zyg3/zyg3 plants, we showed that AtRNL is localized exclusively in the cytoplasm, suggesting that tRNA splicing occurs primarily in the cytoplasm. Analyses using partially rescued embryos showed that mutation in AtRNL compromised splicing of intron-containing tRNA. Mutations of two tRNA endonuclease genes, SEN1 and SEN2, also led to a zygote-lethal phenotype. These results together suggest that tRNA splicing is critical for initiating zygote division in Arabidopsis.

Enhanced electrocatalytic activity of nitrogen-doped olympicene/graphene hybrids for the oxygen reduction reaction.

Developing inexpensive and non-precious metal electrocatalysts for the oxygen reduction reaction (ORR) is among the major goals in fuel cells. Herein, by using density-functional theory calculations, we show that N-doped olympicene/graphene hybrids exhibit unexpectedly high ORR catalytic activity-even comparable to that of the Pt(111) surface. Both graphitic-type and pyridine-type N-doped olympicene/graphene hybrids are highly active for the ORR and have good CO tolerance. The formation of the second H2O molecule is the rate-determining step for the ORR with the graphitic-type hybrid, whereas on the pyridine-type hybrid, it is the formation of OOH. Note that N-doped olympicene/graphene hybrid materials combine the high reactivity of olympicene and the high electrical conductivity of graphene, which allows them to be potentially used as low-cost and non-precious-metal ORR catalysts.

From two-dimension to one-dimension: the curvature effect of silicon-doped graphene and carbon nanotubes for oxygen reduction reaction.

For the goal of practical industrial development of fuel cells, inexpensive, sustainable, and highly efficient electrocatalysts for oxygen reduction reactions (ORR) are highly desirable alternatives to platinum (Pt) and other rare metals. In this work, based on density functional theory, silicon (Si)-doped carbon nanotubes (CNTs) and graphene as metal-free, low cost, and high-performance electrocatalysts for ORR are studied systematically. It is found that the curvature effect plays an important role in the adsorption and reduction of oxygen. The adsorption of O2 becomes weaker as the curvature varies from positive values (outside CNTs) to negative values (inside CNTs). The free energy change of the rate-determining step of ORR on the concave inner surface of Si-doped CNTs is smaller than that on the counterpart of Si-doped graphene, while that on the convex outer surface of Si-doped CNTs is larger than that on Si-doped graphene. Uncovering this new ORR mechanism on silicon-doped carbon electrodes is significant as the same principle could be applied to the development of various other metal-free efficient ORR catalysts for fuel cell applications.

Pb-resistant Pantoea rwandensis promotes maize's growth by altering Pb accumulation in biomass and soil Pb immobilization.

In lead (Pb)-contaminated soil, inoculating phosphate-solubilizing bacteria (PSB) to reduce the phytoavailability of Pb and to change the soil nutrients is an important way to inhibit the Pb uptake by plants. In this study, we isolated the native Pb-resistant Pantoea rwandensis from a tailings site. We employed broth culture and pot experiments to investigate the effect of the inoculation of P. rwandensis on Pb immobilization in the soil, the soil nutrients, the microbial community, and Pb accumulation in the biomass of maize (Zea mays L.). The results showed that P. rwandensis not only tolerated Pb2+ but also dissolved Ca3(PO4)2 by secreting oxalic acid, tartaric acid, lactic acid, and acetic acid, which significantly increased the amount of dissolved P, up to 567.50 mg.L-1. In the pot experiment, the application of culture filtrate, an inoculation with P. rwandensis, or a mixture of culture filtrate and P. rwandensis increased the soil residual Pb by 49.57%, 89.81%, and 41.69%, respectively, compared to the control. Consequently, the increase in the residual Pb in the soil inhibited its uptake by maize, and an inoculation of P. rwandensis or a mixture of culture filtrate and P. rwandensis decreased the accumulation of Pb in the shoot biomass of maize by 61.65% and 72.48% and in the roots of maize by 26.00% and 39.59%, respectively. Meanwhile, P. rwandensis and the mixture of culture filtrate and P. rwandensis increased the shoot biomass of maize by 54.39% and 17.86% and the root biomass of maize by 108.77% and 17.86%, respectively. A P. rwandensis inoculation increased the biodiversity of the fungal community and the abundance of Proteobacteria, Mortierella, and Sphingomonas. Our results demonstrate that an inoculation with P. rwandensis could promote the transformation of Pb fractions and a functional change in the soil bacterial community, ultimately decreasing Pb accumulation in the biomass and promoting the development of maize.

Recent Trends in Self-Powered Photoelectrochemical Sensors: From the Perspective of Signal Output.

Revolutionary developments in analytical chemistry have led to the rapid development of self-powered photoelectrochemical (PEC) sensors. Different from conventional PEC sensors, self-powered PEC sensors do not require an external power source or complex devices for the sensitive detection of targets. As a result, these sensors have enormous application potential for the development of novel portable sensors. An increasing body of work is making excellent progress toward the implementation of self-powered PEC sensors for detection, but there have been no reviews to date. The present review first introduces the state of the art in the development of self-powered PEC sensors. Then, different types of self-powered PEC sensors are summarized and discussed in detail, including their current, power, and potential. Additionally, single- and dual-photoelectrode systems are classified and systematically compared. Finally, the current developments and major challenges that need to be addressed are also summarized. This review provides valuable insights into the current state of self-powered PEC sensors to promote further progress in this field.

Cell death of rice roots under salt stress may be mediated by cyanide-resistant respiration.

Treatment with solutions containing high concentrations of NaCl (200 or 300 mM) induced cell death in rice (Oryza sativa L.) roots, as well as the application of exogenous hydrogen peroxide (H2O2). Moreover, the pretreatment with dimethylthiourea (DMTU), a scavenger of H2O2, partially alleviated the root cell death induced by 200 mM NaCl. These observations suggest that the cell death of rice roots under high salt stress is linked to H2O2 accumulation in vivo. NaCl stress increased the level of cyanide-resistant respiration to some extent and enhanced the transcript levels of the alternative oxidase (AOX) genes AOX1a and AOX1b in rice roots. High-salt-stressed (200 mM NaCl) rice roots pretreated with 1 mM salicylhydroxamic acid (SHAM), a specific inhibitor of alternative oxidase, exhibited higher levels of cell death and H2O2 production than roots subjected to either 200 mM NaCl stress or SHAM treatment alone. These results suggest that cyanide-resistant respiration could play a role in mediating root cell death under high salt stress. Furthermore, this function of cyanide-resistant respiration could relate to its ability to reduce the generation of H2O2.

[Impacts of atovastatin and tinidazole on cardiac muscle inflammation factors of tumor necrosis factor-α, interleukin-1 and metalloproteinase-2 of experimental rabbits with atherosclerosis and periodontitis].

OBJECTIVE: To explore the effects of atovastatin and tinidazole on atherosclerosis and the levels of tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1) and matrix metalloproteinase-2 (MMP-2) in periodontitis. METHODS: A total of 48 male New Zealand white rabbits were randomly divided into 4 groups (n = 12 each): control group (A), atovastatin group (B), tinidazole group (C) and combination group (D, atovastatin + tinidazole). All groups received interventions according to the experiment design. During Week 1-4, mandibular first premolars were used to establish periodontitis model. For Week 1, adaptive feeding was provided with 50% normal diet + 50% high-fat diet. Then a full high fat-diet was used to establish atherosclerosis model. During Week 16-20, experimental drug intervention was administered twice weekly: group A received the same volume of saline, group B atorvastatin tablets 1.5 mg/kg, group C tinidazole tablets 150 mg/kg and group D atorvastatin tablets 1.5 mg/kg + tinidazole tablets 150 mg/kg. At the end of 20-week intervention, the animals were sacrificed to take vascular and heart tissue samples. Immunohistochemistry and fluorescent polymerase chain reaction (PCR) were employed for quantitative determinations. RESULTS: The positive areas of MMP-2 expression in groups B, C and D were smaller than that of group A respectively (35% ± 17%, 69% ± 5%, 30% ± 7% vs 86% ± 9%, all P < 0.05). And the PCR results showed the levels of TNF-α and IL-1 in group D was the lowest of four groups (all P < 0.05). CONCLUSION: Atovastatin and tinidazole can reduce the expression levels of TNF-α, IL-1 and MMP-2 in the rabbits with atherosclerosis and periodontitis respectively. And the combination of both drugs may achieve a better efficacy.

Foliar spraying of indoleacetic acid (IAA) enhances the phytostabilization of Pb in naturally tolerant ryegrass by limiting the root-to-shoot transfer of Pb and improving plant growth.

Exogenous addition of IAA has the potential to improve the metal tolerance and phytostabilization of plants, but these effects have not been systematically investigated in naturally tolerant plants. Ryegrass (Lolium perenne L.) is a typical indigenous plant in the Lanping Pb/Zn mining area with high adaptability. This study investigated the phytostabilization ability and Pb tolerance mechanism of ryegrass in response to Pb, with or without foliar spraying of 0.1 mmol L-1 IAA. The results indicated that appropriate IAA treatment could be used to enhance the phytostabilization efficiency of naturally tolerant plants. Foliar spraying of IAA increased the aboveground and belowground biomass of ryegrass and improved root Pb phytostabilization. Compared to Pb-treated plants without exogenous IAA addition, Pb concentration in the shoots of ryegrass significantly decreased, then increased in the roots after the foliar spraying of IAA. In the 1,000 mg kg-1 Pb-treated plants, Pb concentration in the shoots decreased by 69.9% and increased by 79.1% in the roots after IAA treatment. IAA improved plant growth, especially in soils with higher Pb concentration. Foliar spraying of IAA increased shoot biomass by 35.9% and root biomass by 109.4% in 1,000 mg kg-1 Pb-treated plants, and increased shoot biomass by 196.5% and root biomass by 71.5% in 2,000 mg kg-1 Pb-treated plants. In addition, Pb stress significantly decreased the content of photosynthetic pigments and anti-oxidase activities in ryegrass, while foliar spraying of IAA remedied these negative impacts. In summary, foliar spraying of IAA could increase the biomass and improve the Pb tolerance of ryegrass.

Computational screening of transition-metal doped boron nanotubes as efficient electrocatalysts for water splitting.

The search for efficient and low-cost electrocatalysts for the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) is of utmost importance for the production of hydrogen and oxygen via water splitting. In this work, the catalytic performance of the OER and HER on transition metal doped boron nanotubes (BNTs) was investigated using density functional theory. It was found that the doped transition metal atoms determine the catalytic activity of the BNTs. Rhodium-doped BNTs exhibited excellent OER activity, while cobalt-doped BNTs displayed great catalytic activity toward the HER. Volcano relationships were found between the catalytic activity and the adsorption strength of reaction intermediates. Rhodium- and cobalt-doped BNTs exhibited great OER and HER catalytic activity due to the favorable adsorption strength of reaction intermediates. This work sheds light on the design of novel electrocatalysts for water splitting and provides helpful guidelines for the future development of advanced electrocatalysts.

MicroRNA­21­5p protects melanocytes via targeting STAT3 and modulating Treg/Teff balance to alleviate vitiligo.

Vitiligo (VIT) is caused by loss and degradation of functional epidermal melanocytes. Studies have indicated that melanocyte destruction may be associated with an imbalance between regulatory T cells (Treg cells) and effector T cells (Teff cells). The current study aimed to investigate the molecular mechanism through which Treg/Teff balance affects VIT pathogenesis. To explore this, peripheral blood mononuclear cells were isolated from patients with VIT and healthy individuals. The present study revealed that the proportions of CD4+ T cells, Treg cells and T helper 1 (Th1) cells were decreased in patients with VIT, but those of Teff cells (Th17 and Th22 cells) were increased; additionally, Foxp3 expression was decreased, but the expression levels of interferon­Î³, interleukin (IL)­17A and IL­22 were increased. Furthermore, in patients with VIT, microRNA (miR)­21­5p expression was decreased, while that of STAT3 was increased. Further in vitro experiments in CD4+ T cells revealed that STAT3 was targeted by miR­21­5p. Functional analysis further indicated that miR­21­5p overexpression in Th17­polarized CD4+ T cells decreased the proportion of Teff cells and associated cytokines, such as IL­17A and IL­22, but increased the proportion of Treg cells and Foxp3. However, the effects of miR­21­5p overexpression were partly reversed by STAT3 overexpression. Increased apoptosis of melanocytes was detected after co­culture with Th17­polarized CD4+ T cells in the presence of a miR­21­5p mimic. However, this indirect effect of the miR­21­5p mimic on melanocytes was decreased via STAT3 overexpression. Therefore, miR­21­5p may protect melanocytes via targeting STAT3 and regulating Treg/Teff balance. The current findings may provide a possible treatment method for managing VIT.

Impact of poly(A)-tail G-content on Arabidopsis PAB binding and their role in enhancing translational efficiency.

BACKGROUND: Polyadenylation plays a key role in producing mature mRNAs in eukaryotes. It is widely believed that the poly(A)-binding proteins (PABs) uniformly bind to poly(A)-tailed mRNAs, regulating their stability and translational efficiency. RESULTS: We observe that the homozygous triple mutant of broadly expressed Arabidopsis thaliana PABs, AtPAB2, AtPAB4, and AtPAB8, is embryonic lethal. To understand the molecular basis, we characterize the RNA-binding landscape of these PABs. The AtPAB-binding efficiency varies over one order of magnitude among genes. To identify the sequences accounting for the variation, we perform poly(A)-seq that directly sequences the full-length poly(A) tails. More than 10% of poly(A) tails contain at least one guanosine (G); among them, the G-content varies from 0.8 to 28%. These guanosines frequently divide poly(A) tails into interspersed A-tracts and therefore cause the variation in the AtPAB-binding efficiency among genes. Ribo-seq and genome-wide RNA stability assays show that AtPAB-binding efficiency of a gene is positively correlated with translational efficiency rather than mRNA stability. Consistently, genes with stronger AtPAB binding exhibit a greater reduction in translational efficiency when AtPAB is depleted. CONCLUSIONS: Our study provides a new mechanism that translational efficiency of a gene can be regulated through the G-content-dependent PAB binding, paving the way for a better understanding of poly(A) tail-associated regulation of gene expression.