The structure of B-ARR reveals the molecular basis of transcriptional activation by cytokinin.

The phytohormone cytokinin has various roles in plant development, including meristem maintenance, vascular differentiation, leaf senescence, and regeneration. Prior investigations have revealed that cytokinin acts via a phosphorelay similar to the two-component system by which bacteria sense and respond to external stimuli. The eventual targets of this phosphorelay are type-B ARABIDOPSIS RESPONSE REGULATORS (B-ARRs), containing the conserved N-terminal receiver domain (RD), middle DNA binding domain (DBD), and C-terminal transactivation domain. While it has been established for two decades that the phosphoryl transfer from a specific histidyl residue in ARABIDOPSIS HIS PHOSPHOTRANSFER PROTEINS (AHPs) to an aspartyl residue in the RD of B-ARRs results in a rapid transcriptional response to cytokinin, the underlying molecular basis remains unclear. In this work, we determine the crystal structures of the RD-DBD of ARR1 (ARR1RD-DBD) as well as the ARR1DBD-DNA complex from Arabidopsis. Analyses of the ARR1DBD-DNA complex have revealed the structural basis for sequence-specific recognition of the GAT trinucleotide by ARR1. In particular, comparing the ARR1RD-DBD and ARR1DBD-DNA structures reveals that unphosphorylated ARR1RD-DBD exists in a closed conformation with extensive contacts between the RD and DBD. In vitro and vivo functional assays have further suggested that phosphorylation of the RD weakens its interaction with DBD, subsequently permits the DNA binding capacity of DBD, and promotes the transcriptional activity of ARR1. Our findings thus provide mechanistic insights into phosphorelay activation of gene transcription in response to cytokinin.

Anisotropic cell growth at the leaf base promotes age-related changes in leaf shape in Arabidopsis thaliana.

Plants undergo extended morphogenesis. The shoot apical meristem (SAM) allows for reiterative development and the formation of new structures throughout the life of the plant. Intriguingly, the SAM produces morphologically different leaves in an age-dependent manner, a phenomenon known as heteroblasty. In Arabidopsis thaliana, the SAM produces small orbicular leaves in the juvenile phase, but gives rise to large elliptical leaves in the adult phase. Previous studies have established that a developmental decline of microRNA156 (miR156) is necessary and sufficient to trigger this leaf shape switch, although the underlying mechanism is poorly understood. Here we show that the gradual increase in miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE transcription factors with age promotes cell growth anisotropy in the abaxial epidermis at the base of the leaf blade, evident by the formation of elongated giant cells. Time-lapse imaging and developmental genetics further revealed that the establishment of adult leaf shape is tightly associated with the longitudinal cell expansion of giant cells, accompanied by a prolonged cell proliferation phase in their vicinity. Our results thus provide a plausible cellular mechanism for heteroblasty in Arabidopsis, and contribute to our understanding of anisotropic growth in plants.

Dual-Ligand Red Perovskite Ink for Electrohydrodynamic Printing Color Conversion Arrays over 2540 dpi in Near-Eye Micro-LED Display.

The lack of stability of red perovskite nanocrystals (PeNCs) remains the main problem that restricts their patterning application. In this work, the dual-ligand passivation strategy was introduced to stabilize PeNCs and inhibit their halogen ion migration during high-voltage electrohydrodynamic (EHD) inkjet printing. The as-printed red arrays exhibit the highest emisson intensity and least blue shift compared with samples with other passivation strategies under a high electric field during EHD inkjet printing. Combining with blue and green PeNC inks, single-color and tricolor color conversion layer arrays were successfully printed, with minimum pixel size of 5 µm and the highest spatial resolution of 2540 dpi. The color coordinate of CsPbBrI2 NCs arrays are located close to the red point, with a color gumat of 97.28% of Rec. 2020 standard. All of these show great potential in the application of color conversion layers in a near-eye micro-LED display.

Quantitative Pattern of hPTMs by Mass Spectrometry-Based Proteomics with Implications for Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is known for its aggressive nature, and TNBC management is currently challenging due to the lack of effective targets. Despite the importance of histone post-translational modifications (hPTMs) in breast cancer, their associations with molecular subtypes of breast cancer, especially TNBC, are poorly understood. In this study, a combination of untargeted and targeted proteomics approaches, supplemented by a derivatization method, was applied to breast cancer cells and tissue samples. Untargeted proteomics of eight breast cancer cell lines belonging to different molecular subtypes revealed 36 modified peptides with 12 lysine modification sites in histone H3, and the most frequently reported top 5 histone H3 methylation and acetylation sites were covered. Then, targeted proteomics was carried out to quantify the total 20 target hPTMs at the covered modification sites (i.e., mono-, di-, trimethylation, and acetylation for each site), indicating the difficulty in distinguishing TNBC cells from normal cells. Subsequently, the analysis in TNBC patients revealed significant expression differences in 4 specific hPTMs (H3K14ac, H3K27me1, H3K36me2, and H3K36me3) between TNBC and adjacent normal tissue samples. These unique hPTM patterns allowed for the differentiation of TNBC from normal cases. This finding provides promising implications for advancing targeted treatment strategies for TNBC in the future.

Long-Chain Hydrocarbons from Nonthermal Plasma-Driven Biogas Upcycling.

The burgeoning necessity to discover new methodologies for the synthesis of long-chain hydrocarbons and oxygenates, independent of traditional reliance on high-temperature, high-pressure, and fossil fuel-based carbon, is increasingly urgent. In this context, we introduce a nonthermal plasma-based strategy for the initiation and propagation of long-chain carbon growth from biogas constituents (CO2 and CH4). Utilizing a plasma reactor operating at atmospheric room temperature, our approach facilitates hydrocarbon chain growth up to C40 in the solid state (including oxygenated products), predominantly when CH4 exceeds CO2 in the feedstock. This synthesis is driven by the hydrogenation of CO2 and/or amalgamation of CHx radicals. Global plasma chemistry modeling underscores the pivotal role of electron temperature and CHx radical genesis, contingent upon varying CO2/CH4 ratios in the plasma system. Concomitant with long-chain hydrocarbon production, the system also yields gaseous products, primarily syngas (H2 and CO), as well as liquid-phase alcohols and acids. Our finding demonstrates the feasibility of atmospheric room-temperature synthesis of long-chain hydrocarbons, with the potential for tuning the chain length based on the feed gas composition.

Size selection of intrahepatic lesions for cryoablation contributes to abscopal effect and long-term survival in patients with liver metastatic melanoma receiving PD-1 blockade therapy.

OBJECTIVES: In this study, we aimed to examine parameters of cryoablation, tumor characteristics, and their correlations with distant tumor response and survival of liver metastatic melanoma patients receiving cryoablation and PD-1 blockade (cryo-PD-1) combination treatment. MATERIALS AND METHODS: A retrospective study was conducted among 45 melanoma patients who received combined PD-1 blockade therapy and cryoablation for liver metastasis from 2018 to 2022. Cox regression was utilized to determine the associations between factors and overall survival (OS). Changes in cytokines and immune cell compositions in peripheral blood samples following the combined treatment were investigated, along with their correlations with treatment response. RESULTS: The mean cycle of cryo-PD-1 combination treatment was 2.2 (range, 1-6), and the 3-month overall response rate (RECIST 1.1 criteria) was 26.7%. Of the 21 patients who failed previous PD-1 blockade therapy after diagnosis of liver metastasis, 4 (19.0%) achieved response within 3 months since combination treatment. The diameter of ablated lesion ≤ 30 mm, metastatic organs ≤ 2, and pre-treatment LDH level ≤ 300 U/L were independent prognostic factors for favorable OS. Further analysis showed patients with intrahepatic tumor size of 15-45 mm, and ablated lesion size of ≤ 30 mm had significantly higher 3-month response rate (42.9% vs 12.5%; P = 0.022) and survival time (30.5 vs 14.2 months; P = 0.045) than their counterparts. The average increase in NLR among patients with ablated tumor size of ≤ 3 cm and > 3 cm were 3.59 ± 5.01 and 7.21 ± 12.57, respectively. The average increase in serum IL-6 levels among patients with ablated tumor size of ≤ 3 cm and > 3 cm were 8.62 ± 7.95 pg/ml and 15.40 ± 11.43 pg/ml, respectively. CONCLUSION: Size selection of intrahepatic lesions for cryoablation is important in order to achieve abscopal effect and long-term survival among patients with liver metastatic melanoma receiving PD-1 blockade therapy.

Zincophilic Nanospheres Assembled as Solid-Electrolyte Interphase on Zn Metal Anodes for Reversible High-rate Zn-Ion Storage.

Aqueous Zn-ion batteries (ZIBs) are considered to be one of the most promising energy storage devices in the post-lithium-ion era with fast ionic conductivity, safety, and low cost. However, excessive accumulation of zinc dendrites will fracture and produce dead zinc, resulting in the unsatisfied utilization rate of Zn anodes, which greatly restricts the lifespan of the battery and reduces the reversibility. In this paper, by constructing a protective layer of ZnSnO3 hollow nanospheres in situ growth on the surface of the Zn anode, more zincophilic sites are established on the electrode surface. It demonstrates that uniform deposition of Zn ions by deepening the binding energy with Zn ion and its unique hollow structure shortens the diffusion distance of Zn ions and enhances the reaction kinetics. The assembled Zn-ion hybrid supercapacitor (ZHSC) of ZnSnO3@Zn//AC achieved a long-term lifespan with 4000 cycles at a current density of 10 mA cm-2 with a Coulombic efficiency of 99.31% and capacity retention of 79.6%. This work offers a new path for advanced Zn anodes interphase supporting the long cycle life with large capacities and improving electrochemical reversibility.

Bidirectional mode-locked erbium-doped fiber laser based on an all-fiber gold nanofilm saturable absorber.

We demonstrate a bidirectional mode-locked erbium-doped fiber laser by incorporating gold nanofilm as a saturable absorber (SA). The gold nanofilm SA has the advantages of high stability and high optical damage threshold. Besides, the SA exhibits a large modulation depth of 26% and a low saturation intensity of 1.22 MW/cm2 at 1.56 µm wavelength band, facilitating the mode-locking of bidirectional propagating solitons within a single laser cavity. Bidirectional mode-locked solitons are achieved, with the clockwise pulse centered at 1568.35 nm and the counter-clockwise one at 1568.6 nm, resulting in a slight repetition rate difference of 19 Hz. Moreover, numerical simulations are performed to reveal the counter-propagating dynamics of the two solitons, showing good agreement with the experimental results. The asymmetric cavity configuration gives rise to distinct buildup and evolution dynamics of the two counter-propagating pulses. These findings highlight the advantage of the gold nanofilm SA in constructing bidirectional mode-locked fiber lasers and provide insights for understanding the bidirectional pulse propagation dynamics.

Redundant and specific roles of individual MIR172 genes in plant development.

Evolutionarily conserved microRNAs (miRNAs) usually have high copy numbers in the genome. The redundant and specific roles of each member of a multimember miRNA gene family are poorly understood. Previous studies have shown that the miR156-SPL-miR172 axis constitutes a signaling cascade in regulating plant developmental transitions. Here, we report the feasibility and utility of CRISPR-Cas9 technology to investigate the functions of all 5 MIR172 family members in Arabidopsis. We show that an Arabidopsis plant devoid of miR172 is viable, although it displays pleiotropic morphological defects. MIR172 family members exhibit distinct expression pattern and exert functional specificity in regulating meristem size, trichome initiation, stem elongation, shoot branching, and floral competence. In particular, we find that the miR156-SPL-miR172 cascade is bifurcated into specific flowering responses by matching pairs of coexpressed SPL and MIR172 genes in different tissues. Our results thus highlight the spatiotemporal changes in gene expression that underlie evolutionary novelties of a miRNA gene family in nature. The expansion of MIR172 genes in the Arabidopsis genome provides molecular substrates for the integration of diverse floral inductive cues, which ensures that plants flower at the optimal time to maximize seed yields.

Flavin-containing monooxygenases FMOGS-OXs integrate flowering transition and salt tolerance in Arabidopsis thaliana.

Salt stress substantially leads to flowering delay. The regulation of salt-induced late flowering has been studied at the transcriptional and protein levels; however, the involvement of secondary metabolites has rarely been investigated. Here, we report that FMOGS-OXs (EC 1.14.13.237), the enzymes that catalyze the biosynthesis of glucosinolates (GSLs), promote flowering transition in Arabidopsis thaliana. It has been reported that WRKY75 is a positive regulator, and MAF4 is a negative regulator of flowering transition. The products of FMOGS-OXs, methylsulfinylalkyl GSLs (MS GSLs), facilitate flowering by inducing WRKY75 and repressing the MAS-MAF4 module. We further show that the degradation of MS GSLs is involved in salt-induced late flowering and salt tolerance. Salt stress induces the expression of myrosinase genes, resulting in the degradation of MS GSLs, thereby relieving the promotion of WRKY75 and inhibition of MAF4, leading to delayed flowering. In addition, the degradation products derived from MS GSLs enhance salt tolerance. Previous studies have revealed that FMOGS-OXs exhibit alternative catalytic activity to form trimethylamine N-oxide (TMAO) under salt stress, which activates multiple stress-related genes to promote salt tolerance. Therefore, FMOGS-OXs integrate flowering transition and salt tolerance in various ways. Our study shed light on the functional diversity of GSLs and established a connection between flowering transition, salt resistance, and GSL metabolism.

Parallel-Forms Reliability and Minimal Detectable Change of the Four Telerehabilitation Version Mobility-Related Function Scales in Stroke Survivors.

OBJECTIVE: To investigate the parallel-forms reliability, minimal detectable change with 95% confidence interval (MDC95), and feasibility of the 4 telerehabilitation version mobility-related function scales: Fugl-Meyer Assessment-lower extremity subscale (Tele-FMA-LE), Berg Balance Scale (Tele-BBS), Tinetti Performance Oriented Mobility Assessment-Gait subscale (Tele-POMA-G), and Rivermead Mobility Index (Tele-RMI). DESIGN: Reliability and agreement study and cross-sectional study. SETTING: Medical center. PARTICIPANTS: Stroke survivors' ability to independently walk 3 meters with assistive devices, age of ≥18 years for participants and their partners, stable physical condition, and absence of cognitive impairment (N=60). INTERVENTIONS: Not applicable. MAIN OUTCOMES MEASURES: Parallel-forms reliability and MDC95 of Tele-FMA-LE, Tele-BBS, Tele-POMA-G, and Tele-RMI. RESULTS: No significant differences (P>.05) were observed among the mean scores of the telerehabilitation version and face-to-face version mobility-related function scales. Intraclass correlation coefficients (ICCs) indicated good reliability for most scales, with Tele-FMA-LE, Tele-BBS, and Tele-RMI scores achieving values of 0.81, 0.78, and 0.84. Tele-POMA-G scores demonstrated moderate reliability (ICC=0.72). Weighted kappa (κw) showed good-to-excellent reliability for most individual items (κw>0.60). The MDCs of the Tele-FMA-LE, Tele-BBS, Tele-POMA-G, and Tele-RMI were 5.84, 8.10, 2.74, and 1.31, respectively. Bland-Altman analysis showed adequate agreement between tele-assessment and face-to-face assessment for all scales. The 5 dimensions affirm the robust feasibility of tele-assessment: assessment time, subjective fatigue perception, overall preference, participant satisfaction, and system usability. CONCLUSIONS: The study demonstrates good parallel-forms reliability, MDC, and promising feasibility of the 4 telerehabilitation version mobility-related function scales (Tele-FMA-LE, Tele-BBS, Tele-POMA-G, and Tele-RMI) in survivors of stroke.

Identification of Key Molecular Pathways and Associated Genes as Targets to Overcome Radiotherapy Resistance Using a Combination of Radiotherapy and Immunotherapy in Glioma Patients.

Recent mechanistic studies have indicated that combinations of radiotherapy (RT) plus immunotherapy (via CSF-1R inhibition) can serve as a strategy to overcome RT resistance and improve the survival of glioma mice. Given the high mortality rate for glioma, including low-grade glioma (LGG) patients, it is of critical importance to investigate the mechanism of the combination of RT and immunotherapy and further translate the mechanism from mouse studies to improve survival of RT-treated human glioma patients. Using the RNA-seq data from a glioma mouse study, 874 differentially expressed genes (DEGs) between the group of RT-treated mice at glioma recurrence and the group of mice with combination treatment (RT plus CSF-1R inhibition) were translated to the human genome to identify significant molecular pathways using the KEGG enrichment analysis. The enrichment analysis yields statistically significant signaling pathways, including the phosphoinositide 3-kinase (PI3K)/AKT pathway, Hippo pathway, and Notch pathway. Within each pathway, a candidate gene set was selected by Cox regression models as genetic biomarkers for resistance to RT and response to the combination of RT plus immunotherapies. Each Cox model is trained using a cohort of 295 RT-treated LGG patients from The Cancer Genome Atlas (TCGA) database and validated using a cohort of 127 RT-treated LGG patients from the Chinese Glioma Genome Atlas (CGGA) database. A four-DEG signature (ITGB8, COL9A3, TGFB2, JAG1) was identified from the significant genes within the three pathways and yielded the area under time-dependent ROC curve AUC = 0.86 for 5-year survival in the validation set, which indicates that the selected DEGs have strong prognostic value and are potential intervention targets for combination therapies. These findings may facilitate future trial designs for developing combination therapies for glioma patients.

Remote sensing-based prediction of organic carbon in agricultural and natural soils influenced by salt and sand mining using machine learning.

It is important to keep soil organic carbon (SOC) in balance to ensure soil health and quality. In this manner, mining activities have crucial impacts on SOC stocks, especially in semi-arid and arid regions such as Iran. For this purpose, SOC was measured at 180 randomly selected points in both natural and agricultural soils in the central part of Iran. Machine learning methods, such as GEP (Genetic Expression Programming), SVR (Support Vector Regression), and ANNs (Artificial Neural Networks), were developed and employed to estimate SOC for all sampled points, including both natural and agricultural soils. Following that, topography and remotely sensed data were employed as input variables to improve SOC prediction influenced by mining. The remotely sensed data and topography factors were extracted from Landsat 9 images and Digital Elevation Models (DEMs), respectively. Input variables were considered in three scenarios, including the use of topography factors (scenario I), the use of remote sensing data (scenario II), and the use of both topography factors and remote sensing data (scenario III). The results of this study showed that the most effective model for predicting SOC across all sampled data was SVR (ME = -0.1539%, R2 = 0.642 and RMSE = 0.620%) when employing scenario III. Furthermore, the results indicated that the optimal method for both natural and agricultural soils was the SVR method when employing scenario III. Further analysis through mapping SOC contents showed that mining activities influenced the distribution of SOC in the studied region. Overall, the predicted maps of SOC contents indicated that lower SOC contents were predominantly distributed in the vicinity of salt and sand mines, particularly in salt-rich areas, for both natural and agricultural soils.

Therapeutic potential and possible mechanisms of ginseng for depression associated with COVID-19.

Recently, a global outbreak of COVID-19 has rapidly spread to various national regions. As the number of COVID-19 patients has increased, some of those infected with SARS-CoV-2 have developed a variety of psychiatric symptoms, including depression, cognitive impairment, and fatigue. A distinct storm of inflammatory factors that contribute to the initial disease but also a persistent post-acute phase syndrome has been reported in patients with COVID-19. Neuropsychological symptoms including depression, cognitive impairment, and fatigue are closely related to circulating and local (brain) inflammatory factors. Natural products are currently being examined for their ability to treat numerous complications caused by COVID-19. Among them, ginseng has anti-inflammatory, immune system stimulating, neuroendocrine modulating, and other effects, which may help improve psychiatric symptoms. This review summarizes the basic mechanisms of COVID-19 pneumonia, psychiatric symptoms following coronavirus infections, effects of ginseng on depression, restlessness, and other psychiatric symptoms associated with post-COVID syn-dromes, as well as possible mechanisms underlying these effects.

Cardiolipin Regulates the Activity of the Mitochondrial ABC Transporter ABCB10.

The ATP-binding cassette (ABC) transporter ABCB10 resides in the inner membrane of mitochondria and is implicated in erythropoiesis. Mitochondria from different cell types share some specific characteristics, one of which is the high abundance of cardiolipin. Although previous studies have provided insight into ABCB10, the affinity and selectivity of this transporter toward lipids, particularly those found in the mitochondria, remain poorly understood. Here, native mass spectrometry is used to directly monitor the binding events of lipids to human ABCB10. The results reveal that ABCB10 binds avidly to cardiolipin with an affinity significantly higher than that of other phospholipids. The first three binding events of cardiolipin display positive cooperativity, which is suggestive of specific cardiolipin-binding sites on ABCB10. Phosphatidic acid is the second-best binder of the lipids investigated. The bulk lipids, phosphatidylcholine and phosphatidylethanolamine, display the weakest binding affinity for ABCB10. Other lipids bind ABCB10 with a similar affinity. Functional assays show that cardiolipin regulates the ATPase activity of ABCB10 in a dose-dependent fashion. ATPase activity of ABCB10 was also impacted in the presence of other lipids but to a lesser extent than cardiolipin. Taken together, ABCB10 has a high binding affinity for cardiolipin, and this lipid also regulates the ATPase activity of the transporter.

Catalyst-Free Carbon Dioxide Conversion in Water Facilitated by Pulse Discharges.

By inducing CO2-pulsed discharges within microchannel bubbles and regulating thus-forming plasma microbubbles, we observe high-performance, catalyst-free coformation of hydrogen peroxide (H2O2) and oxalate directly from CO2 and water. With isotope-labeled C18O2 as the feedstock, peaks of H218O16O and H216O2 observed by ex situ surface-enhanced Raman spectra indicate that single-atom oxygen (O) from CO2 dissociations and H2O-derived OH radicals both contribute to H2O2 formation. The global plasma chemistry modeling suggests that high-density, energy-intense electron supply enables high-density CO2- (aq) and HCO2- (aq) formation and their subsequent coupling to produce oxalate. The enhanced solvation of CO2, facilitated by the efficient transport of CxOy ionic species and CO, is demonstrated as a crucial benefit of spark discharges interacting with water at the bubble interface. We expect this plasma microbubble approach to provide a novel power-to-chemical avenue to convert CO2 into valuable H2O2 and oxalic acid platform chemicals, thus leveraging renewable energy resources.

BACH1 encourages ferroptosis by activating KDM4C-mediated COX2 demethylation after cerebral ischemia-reperfusion injury.

It has been confirmed that BTB domain and CNC homologue 1 (BACH1) are involved in ferroptosis-related diseases. However, the function of BACH1 in cerebral ischemia-reperfusion injury (CIRI)-induced ferroptosis remains to be largely unrevealed. First, analysis of differentially expressed genes in CIRI based on the GEO dataset GSE119121 revealed that BACH1 was upregulated in CIRI. BACH1 level was prominently increased in middle cerebral artery occlusion (MCAO)/reperfusion model and oxygen-glucose deprivation/reoxygenation cell model. Further, knock-down of BACH1 markedly reduced iron ion concentration, ROS production, 4-HNE and lipid peroxidation levels and facilitated GSH content, cell viability and protein levels of GPX4 and SLC7A11, while an pcDNA-KDM4C or pcDNA-COX2 combined with BACH1 siRNA could not enhance this effect. Mechanistically, BACH1 bound on the KDM4C promoter to transcriptionally activate its expression. Besides, KDM4C could occupy the promoter locus of the COX2 gene, promoting the COX2 expression by eliminating H3K9me3. Overexpression of KDM4C or COX2 overturned the effects of BACH1 inhibition. In vivo findings displayed that brain infraction, pathological damage and neuronal loss rate in MCAO mice were conspicuously decreased after BACH1 knock-down. This study reveals that BACH1 encourages ferroptosis in neuroblastoma cells and CIRI mouse brain tissues by activating KDM4C-mediated COX2 demethylation.

A spatiotemporally regulated transcriptional complex underlies heteroblastic development of leaf hairs in Arabidopsis thaliana.

Heteroblasty refers to a phenomenon that a plant produces morphologically or functionally different lateral organs in an age-dependent manner. In the model plant Arabidopsis thaliana, the production of trichomes (epidermal leaf hairs) on the abaxial (lower) side of leaves is a heteroblastic mark for the juvenile-to-adult transition. Here, we show that the heteroblastic development of abaxial trichomes is regulated by a spatiotemporally regulated complex comprising the leaf abaxial fate determinant (KAN1) and the developmental timer (miR172-targeted AP2-like proteins). We provide evidence that a short-distance chromatin loop brings the downstream enhancer element into close association with the promoter elements of GL1, which encodes a MYB transcription factor essential for trichome initiation. During juvenile phase, the KAN1-AP2 repressive complex binds to the downstream sequence of GL1 and represses its expression through chromatin looping. As plants age, the gradual reduction in AP2-like protein levels leads to decreased amount of the KAN1-AP2 complex, thereby licensing GL1 expression and the abaxial trichome initiation. Our results thus reveal a novel molecular mechanism by which a heteroblastic trait is governed by integrating age and leaf polarity cue in plants.

Plasma membrane-associated calcium signaling modulates cadmium transport.

Cadmium (Cd) is a toxic heavy element for plant growth and development, and plants have evolved many strategies to cope with Cd stress. However, the mechanisms how plants sense Cd stress and regulate the function of transporters remain very rudimentary. Here, we found that Cd stress induces obvious Ca2+ signals in Arabidopsis roots. Furthermore, we identified the calcium-dependent protein kinases CPK21 and CPK23 that interacted with the Cd transporter NRAMP6 through a variety of protein interaction techniques. Then, we confirmed that the cpk21 23 double mutants significantly enhanced the sensitive phenotype of cpk23 single mutant under Cd stress, while the overexpression and continuous activation of CPK21 and CPK23 enhanced plants tolerance to Cd stress. Multiple biochemical and physiological analyses in yeast and plants demonstrated that CPK21/23 phosphorylate NRAMP6 primarily at Ser489 and Thr505 to inhibit the Cd transport activity of NRAMP6, thereby improving the Cd tolerance of plants. Taken together, we found a plasma membrane-associated calcium signaling that modulates Cd tolerance. These results provide new insights into the molecular breeding of crop tolerance to Cd stress.

Bacteria and Virus Inactivation: Relative Efficacy and Mechanisms of Peroxyacids and Chlor(am)ine.

Peroxyacids (POAs) are a promising alternative to chlorine for reducing the formation of disinfection byproducts. However, their capacity for microbial inactivation and mechanisms of action require further investigation. We evaluated the efficacy of three POAs (performic acid (PFA), peracetic acid (PAA), and perpropionic acid (PPA)) and chlor(am)ine for inactivation of four representative microorganisms (Escherichia coli (Gram-negative bacteria), Staphylococcus epidermidis (Gram-positive bacteria), MS2 bacteriophage (nonenveloped virus), and Φ6 (enveloped virus)) and for reaction rates with biomolecules (amino acids and nucleotides). Bacterial inactivation efficacy (in anaerobic membrane bioreactor (AnMBR) effluent) followed the order of PFA > chlorine > PAA ≈ PPA. Fluorescence microscopic analysis indicated that free chlorine induced surface damage and cell lysis rapidly, whereas POAs led to intracellular oxidative stress through penetrating the intact cell membrane. However, POAs (50 µM) were less effective than chlorine at inactivating viruses, achieving only ∼1-log PFU removal for MS2 and Φ6 after 30 min of reaction in phosphate buffer without genome damage. Results suggest that POAs' unique interaction with bacteria and ineffective viral inactivation could be attributed to their selectivity toward cysteine and methionine through oxygen-transfer reactions and limited reactivity for other biomolecules. These mechanistic insights could inform the application of POAs in water and wastewater treatment.