Ca2+-dependent phosphorylation of NRAMP1 by CPK21 and CPK23 facilitates manganese uptake and homeostasis in Arabidopsis.

Homeostasis of the essential micronutrient manganese (Mn) is crucially determined through availability and uptake efficiency in all organisms. Mn deficiency of plants especially occurs in alkaline and calcareous soils, seriously restricting crop yield. However, the mechanisms underlying the sensing and signaling of Mn availability and conferring regulation of Mn uptake await elucidation. Here, we uncover that Mn depletion triggers spatiotemporally defined long-lasting Ca2+ oscillations in Arabidopsis roots. These Ca2+ signals initiate in individual cells, expand, and intensify intercellularly to transform into higher-order multicellular oscillations. Furthermore, through an interaction screen we identified the Ca2+-dependent protein kinases CPK21 and CPK23 as Ca2+ signal-decoding components that bring about translation of these signals into regulation of uptake activity of the high-affinity Mn transporter natural resistance associated macrophage proteins 1 (NRAMP1). Accordingly, a cpk21/23 double mutant displays impaired growth and root development under Mn-limiting conditions, while kinase overexpression confers enhanced tolerance to low Mn supply to plants. In addition, we define Thr498 phosphorylation within NRAMP1 as a pivot mechanistically determining NRAMP1 activity, as revealed by biochemical assays and complementation of yeast Mn uptake and Arabidopsis nramp1 mutants. Collectively, these findings delineate the Ca2+-CPK21/23-NRAMP1 axis as key for mounting plant Mn homeostasis.

CPK10 protein kinase regulates Arabidopsis tolerance to boron deficiency through phosphorylation and activation of BOR1 transporter.

Boron (B) is crucial for plant growth and development. B deficiency can impair numerous physiological and metabolic processes, particularly in root development and pollen germination, seriously impeding crop growth and yield. However, the molecular mechanism underlying boron signal perception and signal transduction is rather limited. In this study, we discovered that CPK10, a calcium-dependent protein kinase in the CPK family, has the strongest interaction with the boron transporter BOR1. Mutations in CPK10 led to growth and root development defects under B-deficiency conditions, while constitutively active CPK10 enhanced plant tolerance to B deficiency. Furthermore, we found that CPK10 interacted with and phosphorylated BOR1 at the Ser689 residue. Through various biochemical analyses and complementation of B transport in yeast and plants, we revealed that Ser689 of BOR1 is important for its transport activity. In summary, these findings highlight the significance of the CPK10-BOR1 signaling pathway in maintaining B homeostasis in plants and provide targets for the genetic improvement of crop tolerance to B-deficiency stress.

A tomato NAC transcription factor, SlNAP1, directly regulates gibberellin-dependent fruit ripening.

In tomato (Solanum lycopersicum), the ripening of fruit is regulated by the selective expression of ripening-related genes, and this procedure is controlled by transcription factors (TFs). In the various plant-specific TF families, the no apical meristem (NAM), Arabidopsis thaliana activating factor 1/2 (ATAF1/2), and cup-shaped cotyledon 2 (CUC2; NAC) TF family stands out and plays a significant function in plant physiological activities, such as fruit ripening (FR). Despite the numerous genes of NAC found in the tomato genome, limited information is available on the effects of NAC members on FR, and there is also a lack of studies on their target genes. In this research, we focus on SlNAP1, which is a NAC TF that positively influences the FR of tomato. By employing CRISPR/Cas9 technology, compared with the wild type (WT), we generated slnap1 mutants and observed a delay in the ethylene production and color change of fruits. We employed the yeast one-hybrid (Y1H) and dual-luciferase reporter (DLR) assays to confirm that SlNAP1 directly binds to the promoters of two crucial genes involved in gibberellin (GA) degradation, namely SlGA2ox1 and SlGA2ox5, thus activating their expression. Furthermore, through a yeast two-hybrid (Y2H), bimolecular fluorescence complementation (BIFC) and luciferase (LUC) assays, we established an interaction between SlNAP1 and SlGID1. Hence, our findings suggest that SlNAP1 regulates FR positively by activating the GA degradation genes directly. Additionally, the interaction between SlNAP1 and SlGID1 may play a role in SlNAP1-induced FR. Overall, our study provides important insights into the molecular mechanisms through which NAC TFs regulate tomato FR via the GA pathway.

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.

CBL1/9-CIPK23-NRAMP1 axis regulates manganese toxicity.

Manganese (Mn) is an essential micronutrient in plants. However, excessive Mn absorption in acidic soils can cause Mn toxicity, which adversely affects plant growth and crop yields. At present, acidic soils cover c. 30% of the Earth's surface. However, the mechanism underpinning Mn uptake remains largely unknown. We identified cbl1/9 and cipk23 mutants exhibiting high-Mn-sensitive phenotype through the reverse genetics method. Furthermore, we identified the CIPK23 phosphorylated NRAMP1 through a variety of protein interaction techniques and protein kinase assays. Here, we demonstrated that two calcineurin B-like proteins, CBL1/9, and their interacting kinase CIPK23 positively regulated the tolerance of Mn toxicity in Arabidopsis. The cbl1 cbl9 double mutant and cipk23 mutants exhibited high-Mn-sensitive phenotypes, which manifested as decreased primary root length, biomass, and chlorophyll concentration, and higher accumulation of Mn. In addition, CIPK23 interacted with and phosphorylated the Mn transporter NRAMP1 primarily at Ser20/22 in vitro and in vivo, and thereby induced clathrin-mediated endocytosis of NRAMP1 to reduce its distribution on the plasma membrane and enhance plant tolerance to Mn toxicity. In summary, we found that the CBL1/9-CIPK23-NRAMP1 module regulates the tolerance to high-Mn toxicity and provide insight into a mechanism of the tolerance of plants to Mn toxicity.

The FBXO32/ATR/ATM axis acts as a molecular switch to control the sensitivity of osteosarcoma cells to irradiation through its regulation of EXO1 expression.

Osteosarcoma (OS) is the most common primary bone cancer in children and adolescents. In clinical treatments, the insensitivity of OS to conventional radiotherapy regimens significantly contributes to poor patient prognosis and survival. EXO1 is responsible for DNA repair pathways and telomere maintenance. Meanwhile, ATM and ATR are considered switches because they can regulate the expression of EXO1. However, their expression and interaction in OS cells under irradiation (IR) remain unclear. This study aims to investigate the roles of FBXO32, ATM, ATR and EXO1 in OS radiotherapy insensitivity and poor patient prognosis and explore potential pathogenic mechanisms. Bioinformatics is employed to analyse differential gene expression and correlations with prognosis in OS. Cell counting kit 8 assay, clone formation assay, and flow cytometry are used to evaluate cell survival and apopotosis under IR. Co-IP assay is used to detect protein‒protein interactions. Bioinformatics analysis reveals that EXO1 is closely related to survival, apoptosis and poor prognosis in OS. Silencing of EXO1 suppresses cell proliferation and increases the sensitivity of OS cells. Molecular biological experiments show that ATM and ATR act as switches to regulate EXO1 expression under IR. Higher expression of EXO1, which is closely correlated with IR insensitivity and poorer prognosis, might be used as a prognostic indicator for OS. Phosphorylated ATM enhances the expression of EXO1, and phosphorylated ATR induces the degradation of EXO1. More importantly, FBXO32 degrades ATR via ubiquitination in a time-dependent manner. Our data may provide a reference for future research in the mechanisms, clinical diagnosis, and treatment of OS.

The Fng3 ING protein regulates H3 acetylation and H4 deacetylation by interacting with two distinct histone-modifying complexes.

The steady-state level of histone acetylation is maintained by histone acetyltransferase (HAT) and histone deacetylase (HDAC) complexes. INhibitor of Growth (ING) proteins are key components of the HAT or HDAC complexes but their relationship with other components and roles in phytopathogenic fungi are not well-characterized. Here, the FNG3 ING gene was functionally characterized in the wheat head blight fungus Fusarium graminearum. Deletion of FNG3 results in defects in fungal development and pathogenesis. Unlike other ING proteins that are specifically associated with distinct complexes, Fng3 was associated with both NuA3 HAT and FgRpd3 HDAC complexes to regulate H3 acetylation and H4 deacetylation. Whereas FgNto1 mediates the FgSas3-Fng3 interaction in the NuA3 complex, Fng3 interacted with the C-terminal region of FgRpd3 that is present in Rpd3 orthologs from filamentous fungi but absent in yeast Rpd3. The intrinsically disordered regions in the C-terminal tail of FgRpd3 underwent phase separation, which was important for its interaction with Fng3. Furthermore, the ING domain of Fng3 is responsible for its specificities in protein-protein interactions and functions. Taken together, Fng3 is involved in the dynamic regulation of histone acetylation by interacting with two histone modification complexes, and is important for fungal development and pathogenicity.

KUP9 maintains root meristem activity by regulating K+ and auxin homeostasis in response to low K.

Potassium (K) is essential for plant growth and development. Here, we show that the KUP/HAK/KT K+ transporter KUP9 controls primary root growth in Arabidopsis thaliana. Under low-K+ conditions, kup9 mutants displayed a short-root phenotype that resulted from reduced numbers of root cells. KUP9 was highly expressed in roots and specifically expressed in quiescent center (QC) cells in root tips. The QC acts to maintain root meristem activity, and low-K+ conditions induced QC cell division in kup9 mutants, resulting in impaired root meristem activity. The short-root phenotype and enhanced QC cell division in kup9 mutants could be rescued by exogenous auxin treatment or by specifically increasing auxin levels in QC cells, suggesting that KUP9 affects auxin homeostasis in QC cells. Further studies showed that KUP9 mainly localized to the endoplasmic reticulum (ER), where it mediated K+ and auxin efflux from the ER lumen to the cytoplasm in QC cells under low-K+ conditions. These results demonstrate that KUP9 maintains Arabidopsis root meristem activity and root growth by regulating K+ and auxin homeostasis in response to low-K+ stress.

Strigolactone is involved in nitric oxide-enhanced the salt resistance in tomato seedlings.

Both strigolactones (SLs) and nitric oxide (NO) are regulatory signals with diverse roles during stress responses. At present, the interaction and mechanism of SLs and NO in tomato salt tolerance remain unclear. In the current study, tomato 'Micro-Tom' was used to study the roles and interactions of SLs and NO in salinity stress tolerance. The results show that 15 µM SLs synthetic analogs GR24 and 10 µM NO donor S-nitrosoglutathione (GSNO) promoted seedling growth under salt stress. TIS108 (an inhibitor of strigolactone synthesis) suppressed the positive roles of NO in tomato growth under salt stress, indicating that endogenous SLs might be involved in NO-induced salt response in tomato seedlings. Meanwhile, under salt stress, GSNO or GR24 treatment induced the increase of endogenous SLs content in tomato seedlings. Moreover, GR24 or GSNO treatment effectively increased the content of chlorophyll, carotenoids and ascorbic acid (ASA), and enhanced the activities of antioxidant enzymes (superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase), glutathione reductase (GR) and cleavage dioxygenase (CCD) enzyme. Additionally, GSNO or GR24 treatment also up-regulated the expression of SLs synthesis genes (SlCCD7, SlCCD8, SlD27 and SlMAX1) and its signal transduction genes (SlD14 and SlMAX2) in tomato seedlings under salt stress. While, a strigolactone synthesis inhibitor TIS108 blocked the increase of endogenous SLs, chlorophyll, carotenoids and ASA content, and antioxidant enzyme, GR, CCD enzyme activity and SLs-related gene expression levels induced by GSNO. Thus, SLs may play an important role in NO-enhanced salinity tolerance in tomato seedlings by increasing photosynthetic pigment content, enhancing antioxidant capacity and improving endogenous SLs synthesis.

A 3D Attitude Estimation Method Based on Attitude Angular Partial Feedback for Polarization-Based Integrated Navigation System.

Polarization (POL) navigation is inspired by insects' behavior of precepting celestial polarization patterns to orient themselves. It has the advantages of being autonomous and having no accumulative error, which allows it to be used to correct the errors of the inertial navigation system (INS). The integrated navigation system of the POL-based solar vector with INS is capable of 3D attitude determination. However, the commonly used POL-based integrated navigation system generally implements the attitude update procedure without considering the performance difference with different magnitudes of the angles between the solar-vector and body-axes of the platform (S-B angles). When one of the S-B angles is small enough, the estimated accuracy of the attitude angle by the INS/POL is worse than that of the strapdown inertial navigation system. To minimize the negative impact of POL in this situation, an attitude angular adaptive partial feedback method is proposed. The S-B angles are used to construct a partial feedback factor matrix to adaptively adjust the degree of error correction for INS. The results of simulation and real-world experiments demonstrate that the proposed method can improve the accuracy of 3D attitude estimation compared with the conventional all-feedback method for small S-B angles especially for yaw angle estimation.

Caffeine-related effects on cognitive performance: Roles of apoptosis in rat hippocampus following sleep deprivation.

Caffeine is a common stimulant widely existed in food and has stimulatory effects on the central nervous system, shift-work individuals often rely on caffeine to maintain attention and keep awake. Although sleep deprivation (SD) is widely considered as an independent risk factor for cognition retardations, however, little is well understood about the synergistic role of caffeine dosage and SD for cognitive performance. This research intended to investigate the underlying molecular mechanism of varying caffeine doses on cognitive function after sleep deprivation. The results revealed that SD attenuated the cognitive dysfunction, associated with ultrastructure damage and pyramidal neuron loss in the hippocampus, decreased in the level of VIP and AVP. SD also significantly accelerated the neuropeptide-associated apoptosis in the hippocampus, which may modulate via the cAMP-PKA-CREB signal path axis and activation of the downstream apoptosis genes. Additionally, the data indicated that low-dose caffeine (LC) contributed to cognitive enhancement, and high-dose caffeine (HC) aggravated cognitive impairment by modulating hippocampal neuronal apoptosis. Our studies suggest that caffeine, particularly in high dosage, may be a potential factor to influence the neurocognitive outcome caused by sleep loss, and the appropriate amount of caffeine ingested after sleep deprivation deserves serious consideration.

Fast digital lossy compression for X-ray ptychographic data.

Increases in X-ray brightness from synchrotron light sources lead to a requirement for higher frame rates from hybrid pixel array detectors (HPADs), while also favoring charge integration over photon counting. However, transfer of the full uncompressed data will begin to constrain detector design, as well as limit the achievable continuous frame rate. Here a data compression scheme that is easy to implement in a HPAD's application-specific integrated circuit (ASIC) is described, and how different degrees of compression affect image quality in ptychography, a commonly employed coherent imaging method, is examined. Using adaptive encoding quantization, it is shown in simulations that one can digitize signals up to 16383 photons per pixel (corresponding to 14 bits of information) using only 8 or 9 bits for data transfer, with negligible effect on the reconstructed image.

An oncolytic adenovirus delivering TSLC1 inhibits Wnt signaling pathway and tumor growth in SMMC-7721 xenograft mice model.

Tumor suppressor in lung cancer-1 (TSLC1) was first identified as a tumor suppressor for lung cancer, and frequently downregulated in various types of cancers including hepatocellular carcinoma (HCC). The Wnt pathway plays a critical role in tumorigenesis, migration, and invasion in HCC. However, the function of TSLC1 in modulating Wnt signaling in HCC is unclear. In this study, we evaluated the effect of TSLC1-armed oncolytic adenovirus (S24-TSLC1) on the Wnt/ß-catenin pathway, cell viability, invasion and migration abilities of HCC in vitro and the growth of SMMC-7721-xenografted tumor in mice model. We detected the expression of TSLC1 in tumor samples and HCC cell lines. The results showed that TSLC1 expression was low in HCC, but high in pericarcinomatous tissue and normal cells, which implied that TSLC1 is a tumor suppressor of liver cancer. S24-TSLC1 exhibited an antitumor effect on HCC cell growth in vitro, but did little damage to normal liver cells. Overexpression of TSLC1 downregulated the transcriptional activity of TCF4/ß-catenin and inhibited the mRNA or protein expression of Wnt target genes cyclinD1 and c-myc. S24-TSLC1 also inhibited the invasion and migration of HCC cells. Animal experiments further confirmed that S24-TSLC1 significantly inhibited tumor growth of the SMMC-7721-xenografted tumor. In conclusion, TSLC1 could downregulate the Wnt signal pathway and suppress HCC cell growth, migration and invasion, suggesting that S24-TSLC1 may be a potent antitumor agent for future clinical trials in liver cancer treatment.

Bionic Integrated Positioning Mechanism Based on Bioinspired Polarization Compass and Inertial Navigation System.

In this paper, to address the problem of positioning accumulative errors of the inertial navigation system (INS), a bionic autonomous positioning mechanism integrating INS with a bioinspired polarization compass is proposed. In addition, the bioinspired positioning system hardware and the integration model are also presented. Concerned with the technical issue of the accuracy and environmental adaptability of the integrated positioning system, the sun elevation calculating method based on the degree of polarization (DoP) and direction of polarization (E-vector) is presented. Moreover, to compensate for the latitude and longitude errors of INS, the bioinspired positioning system model combining the polarization compass and INS is established. Finally, the positioning performance of the proposed bioinspired positioning system model was validated via outdoor experiments. The results indicate that the proposed system can compensate for the position errors of INS with satisfactory performance.

Production of phenolic compounds and antioxidant activity via bioconversion of wheat straw by Inonotus obliquus under submerged fermentation with the aid of a surfactant.

BACKGROUND: This study investigated the effect of surfactants on wheat straw biodegradation and the growth-associated generation of exo- and endo-phenolic compounds (EPC and IPC) and antioxidant activity expression by liquid-cultured Inonotus obliquus, an edible and medicinal mushroom, also known as a white rot fungus. Changes in the chemical composition and multiscale structure of wheat straw, in the production and activity of EPC and IPC and in individual flavonoids were analyzed. RESULTS: Fungal pretreatment decreased significantly the contents of all lignocellulose components, increased and enlarged substrate porosity and caused changes in the structure of wheat straw with the aid of Triton X-100. A gradual increase in EPC and IPC production was observed up to 6.4- and 1.5-fold for 9 days. The EPC obtained on day 9 showed the highest antioxidant activity (IC50 of 30.96 mg L-1 ) against 2,2-diphenyl-1-picrylhydrazyl radicals. High-performance liquid chromatographic results indicated the presence of high amounts of epicatechin-3-gallate (ECG; (374.9 mg g-1 ) and epigallocatechin-3-gallate (EGCG; 447.2 mg g-1 ) in the EPC; other polyphenols were also enhanced but to a lesser extent. Surfactant supplementation was effective in enhancing flavonoid production and in increasing antioxidant activity in EPC. CONCLUSIONS: The results indicated enhanced accumulation of phenolic compounds, particularly ECG and EGCG in Inonotus obliquus via biodegradation and bioconversion of lignocellulose residues. They also indicated enhancement in the production of several flavonoids and also an increase in antioxidant activity in the product by a surfactant-treated process, which may be a useful way of exploiting underused lignocellulosic residues to various high-added-value functional ingredients. © 2020 Society of Chemical Industry.

Protocol for optically pumping AlH+ to a pure quantum state.

We propose an optical pumping scheme to prepare trapped AlH+ molecules in a pure state, the stretched hyperfine state of the rovibronic ground manifold |X2Σ+, v = 0, N = 0 . Our scheme utilizes linearly-polarized and circularly-polarized fields of a broadband pulsed laser to cool the rotational degree of freedom and drive the population to the hyperfine state, respectively. We simulate the population dynamics by solving a representative system of rate equations that accounts for the laser fields, blackbody radiation, and spontaneous emission. In order to model the hyperfine structure, new hyperfine constants of the A2Π excited state were computed using a RASSCF wavefunction. We find that adding an infrared laser to drive the 1-0 vibrational transition within the X2Σ+ manifold accelerates the cooling process. The results show that, under optimal conditions, the population in the target state of the rovibronic ground manifold can reach 63% after 68 µs (330 ms) and 95% after 25 ms (1.2 s) with (without) the infrared laser.

Sensor Modeling and Calibration Method Based on Extinction Ratio Error for Camera-Based Polarization Navigation Sensor.

The performance of camera-based polarization sensors largely depends on the estimated model parameters obtained through calibration. Limited by manufacturing processes, the low extinction ratio and inconsistency of the polarizer can reduce the measurement accuracy of the sensor. To account for the challenges, one extinction ratio coefficient was introduced into the calibration model to unify the light intensity of two orthogonal channels. Since the introduced extinction ratio coefficient is associated with degree of polarization (DOP), a new calibration method considering both azimuth of polarization (AOP) error and DOP error for the bionic camera-based polarization sensor was proposed to improve the accuracy of the calibration model parameter estimation. To evaluate the performance of the proposed camera-based polarization calibration model using the new calibration method, both indoor and outdoor calibration experiments were carried out. It was found that the new calibration method for the proposed calibration model could achieve desirable performance in terms of stability and robustness of the calculated AOP and DOP values.

Sexual specific functions of Tub1 beta-tubulins require stage-specific RNA processing and expression in Fusarium graminearum.

The wheat head blight fungus Fusarium graminearum has two highly similar beta-tubulin genes with overlapping functions during vegetative growth but only TUB1 is important for sexual reproduction. To better understand their functional divergence during ascosporogenesis, in this study we characterized the sequence elements important for stage-specific functions of TUB1. Deletion of TUB1 blocked the late but not initial stages of perithecium formation. Perithecia formed by tub1 mutant had limited ascogenous hyphae and failed to develop asci. Silencing of TUB1 by MSUD also resulted in defects in ascospore formation. Interestingly, the 3'-UTR of TUB1 was dispensable for growth but essential for its function during sexual reproduction. RIP mutations that specifically affected Tub1 functions during sexual reproduction also were identified in two ascospore progeny. Furthermore, site-directed mutagenesis showed that whereas the non-editable mutations at three A-to-I RNA editing sites had no effects, the N347D (not T362D or I368V) edited mutation affected ascospore development. In addition, the F167Y, but not E198K or F200Y, mutation in TUB1 conferred tolerance to carbendazim and caused a minor defect in sexual reproduction. Taken together, our data indicate TUB1 plays an essential role in ascosporogenesis and sexual-specific functions of TUB1 require stage-specific RNA processing and Tub1 expression.

CoCl2-promoted TEMPO oxidative homocoupling of indoles: access to tryptanthrin derivatives.

A novel TEMPO/CoCl2-promoted aerobic oxidation of indoles was developed. The reaction provided one-step access to tryptanthrin derivatives in moderate to good yields and excellent regioselectivity via a cascade process. The reactions could be carried out under mild reaction conditions with varying functional group tolerance, especially halogen functional groups. Mechanistic studies disclosed that the oxygen atom in the desired product originated from molecular dioxygen.