ABA functions in low phosphate-induced anthocyanin accumulation through the transcription factor ABI5 in Arabidopsis.

KEY MESSAGE: ABI5 functions in ABA-mediated anthocyanin accumulation in plant response to low phosphate. Low phosphate (LP)-induced anthocyanin biosynthesis and accumulation play an important role in plant adaptive response to phosphate starvation conditions. However, whether and how the stress phytohormone abscisic acid (ABA) participates in LP-induced anthocyanin accumulation remain elusive. Here, we report that ABA is required for LP-induced anthocyanin accumulation in Arabidopsis thaliana. Disrupting ABA DEFICIENT2 (ABA2), a key ABA-biosynthetic gene, or BETA-GLUCOSIDASE1 (BG1), a major gene implicated in converting conjugated ABA to active ABA, significantly impairs LP-induced anthocyanin accumulation, as LP-induced expression of the anthocyanin-biosynthetic genes Chalcone Synthase (CHS) is dampened in the aba2 and bg1 mutant. In addition, LP-induced anthocyanin accumulation is defective in the mutants of ABA signaling pathway, including ABA receptors, ABA Insensitive2, and the transcription factors ABA Insensitive5 (ABI5), suggesting a role of ABI5 in ABA-mediated upregulation of anthocyanin-biosynthetic genes in plant response to LP. Indeed, LP-induced expression of CHS is repressed in the abi5-7 mutant but further promoted in the ABI5-overexpressing plants compared to the wild-type. Moreover, ABI5 can bind to and transcriptionally activate CHS, and the defectiveness of LP-induced anthocyanin accumulation in abi5-7 can be restored by overexpressing CHS. Collectively, our findings illustrates that ABI5 functions in ABA-mediated LP-induced anthocyanin accumulation in Arabidopsis.

Proteomics analysis of histone deacetylase inhibitor-resistant solid tumors reveals resistant signatures and potential drug combinations.

Histone deacetylase inhibitors (HDACis) are important drugs for cancer therapy, but the indistinct resistant mechanisms of solid tumor therapy greatly limit their clinical application. In this study we conducted HDACi-perturbated proteomics and phosphoproteomics analyses in HDACi-sensitive and -resistant cell lines using a tandem mass tag (TMT)-based quantitative proteomic strategy. We found that the ribosome biogenesis proteins MRTO4, PES1, WDR74 and NOP16 vital to tumorigenesis might regulate the tumor sensitivity to HDACi. By integrating HDACi-perturbated protein signature with previously reported proteomics and drug sensitivity data, we predicted and validated a series of drug combination pairs potentially to enhance the sensitivity of HDACi in diverse solid tumor. Functional phosphoproteomic analysis further identified the kinase PDK1 and ROCK as potential HDACi-resistant signatures. Overall, this study reveals the potential HDACi-resistant signatures and may provide promising drug combination strategies to attenuate the resistance of solid tumor to HDACi.

HbBIN2 Functions in Plant Cold Stress Resistance through Modulation of HbICE1 Transcriptional Activity and ROS Homeostasis in Hevea brasiliensis.

Cold stress poses significant limitations on the growth, latex yield, and ecological distribution of rubber trees (Hevea brasiliensis). The GSK3-like kinase plays a significant role in helping plants adapt to different biotic and abiotic stresses. However, the functions of GSK3-like kinase BR-INSENSITIVE 2 (BIN2) in Hevea brasiliensis remain elusive. Here, we identified HbBIN2s of Hevea brasiliensis and deciphered their roles in cold stress resistance. The transcript levels of HbBIN2s are upregulated by cold stress. In addition, HbBIN2s are present in both the nucleus and cytoplasm and have the ability to interact with the INDUCER OF CBF EXPRESSION1(HbICE1) transcription factor, a central component in cold signaling. HbBIN2 overexpression in Arabidopsis displays decreased tolerance to chilling stress with a lower survival rate and proline content but a higher level of electrolyte leakage (EL) and malondialdehyde (MDA) than wild type under cold stress. Meanwhile, HbBIN2 transgenic Arabidopsis treated with cold stress exhibits a significant increase in the accumulation of reactive oxygen species (ROS) and a decrease in the activity of antioxidant enzymes. Further investigation reveals that HbBIN2 inhibits the transcriptional activity of HbICE1, thereby attenuating the expression of C-REPEAT BINDING FACTOR (HbCBF1). Consistent with this, overexpression of HbBIN2 represses the expression of CBF pathway cold-regulated genes under cold stress. In conclusion, our findings indicate that HbBIN2 functions as a suppressor of cold stress resistance by modulating HbICE1 transcriptional activity and ROS homeostasis.

Two-dimensional AlB4/Al2B2: high-performance Dirac anode materials for sodium-ion batteries.

Sodium-ion batteries (SIBs) have attracted much attention due to their abundant earth-reserves and low cost. Two-dimensional (2D) Dirac materials show great application prospects as anodes for SIBs because of their excellent electronic conductivity. We explore the performances of AlB4 (Al2B2) monolayers and bilayers as anodes for SIBs by using first-principles calculations. The AlB4 (Al2B2) monolayer exhibits a high theoretical storage capacity of 954.15 (709.17) mA h g-1 and a low diffusion barrier of 0.36 (0.03) eV. The calculated average open-circuit voltage (0.68/0.18 V) falls within the acceptance range of 0.1-1.0 V for anode materials. The fully sodiated AlB4 (Al2B2) monolayer shows a tiny lattice expansion of 0.9% (2.4%), suggesting good reversibility. Furthermore, in comparison with the AlB4 (Al2B2) monolayer, the AlB4 (Al2B2) bilayer can provide stronger binding with Na on the outside surface. These results contribute to a better understanding of the AlB4 (Al2B2) monolayers and bilayers as potential high-performance anode materials for SIBs.

[Analysis of the clinical effect of percutaneous pedicle screw fixation combined with transpedicular bone grafting in the treatment of thoracolumbar fracture].

OBJECTIVE: To investigate the clinical efficacy of percutaneous screw fixation combined with minimally invasive transpedicular bone grafting and non-bone grafting in the treatment of thoracolumbar fractures. METHODS: From Janury 2021 to June 2022, 40 patients with thoracolumbar fracture were divided into the experimental group and the control group. There were 26 patients in the experimental group, including 21 males and 5 females with an aberage age of (47.3±12.3) years old, who underwent percutaneous pedicle screw fixation combined with transpedicular autogenous bone grafting. In the control group, 14 patients received percutaneous pedicle screw fixation only. including 7 makes and 7 females with an average age of (50.2±11.2) years old. The operative time, intraoperative blood loss, anterior height ratio of injured vertebrae, Cobb angle, visual analogue score (VAS), MacNab scores, loosening or broken of the implants. were compared and analyzed. RESULTS: There was no significant difference in operation time, intraoperative blood loss, VAS and anterior height ratio of injured vertebrae between the two groups. Compared with the preoperative results, VAS and anterior height ratio of injured vertebrae were improved statistically(P<0.05). For Cobb angle of injured vertebra, there was no significant difference between the two groups before surgery (P=0.766). While at 1 week, 3 months and 12 months after surgery, there were statistically differences between the two groups (P values were 0.042, 0.007 and 0.039, respectively). The Cobb angle of injured vertebrae one year after operation was statistically decreased in both groups compared with that before surgery (P<0.001). One year after surgery, the excellent and good rate of Macnab scores was 96.15% in the experimental group and 92.86% in the control group, and there was no statistical differences between the two groups (P=0.648). There was one patient in the control group suffering superficial wound infection on the third day, which was cured by dressing change and anti-infection treatment. There were no postoperative screw loosening and broken in both groups. CONCLUSION: The two surgical methods have the advantages of less trauma, less pain and quicker recovery, which can restore the height of the injured vertebra, reconstruct the spinal sequence and reduce the fracture of the vertebral body. Transpedicular autogenous bone grafting can increase the stability of the fractured vertebra and maintain the height of the vertebra better after surgery, thus reducing the possibility of complications such as kyphosis, screw loosening and broken.

Diterpenoids from Euphorbia fischeriana with Kv1.3 Inhibitory Activity.

Euphorbia diterpenoids possess inhibitory effects of Kv1.3 ion channel, but most of this research has focused on diterpenoids with jatrophane-related or ingenane-related skeletons. In the present study, nine undescribed (1-9) and 16 known (10-25) diterpenoids, based on jatrophane, lathyrane, ingenane, abietane, and atisane skeletons, were identified from the methanol extract of the aerial parts of Euphorbia fischeriana. The structures were established by analysis of the spectroscopic data as well as by single-crystal X-ray diffraction analysis. Among the isolated diterpenoids, macrocyclic jatrophanes and lathyranes exerted Kv1.3 blocking activity. Compound 8 exhibited good selectivity on the inhibition of the Kv 1.3 channel rather than hERG channel, with a selectivity index over 7.0. The selective activity of lathyrane diterpenoids indicates that macrocyclic diterpenoids have the potential to be further investigated as therapeutic agents for the treatment of autoimmune diseases.

Anti-inflammatory lanostane triterpenoids with rearranged spirobi[indene] scaffold and their biogenetically related analogues from Euphorbia maculata.

Phytochemical investigations on the ethanol extract of the whole plant of Euphorbia maculata Linn. Resulted in the identification of 16 lanostane-related triterpenoids, including 11 undescribed ones, namely spiromaculatols A-C (1-3) and euphomaculatoids A-H (4-11). The structural determinations of the previously undescribed ones (1-11) were elucidated based on the interpretation of comprehensive spectroscopic data, quantum chemical calculation, as well as X-ray crystallographic experiments. Spiromaculatols A-C (1-3) possess a rare spirobi [indane] skeleton, which was biosynthetically derived from the 7 (8 â†’ 9)-abeo bond migration of lanostane precursors. The biological activity of compounds 1-3, 5, 7, and 12-13 displayed inhibitory effect on the release of NO in an LPS-activated RAW264.7 cells model. Molecular mechanism study indicated that the most potent spiromaculatol C (3) can reduce the nuclear translocation of NF-κB p65 and decrease the transcriptional expressions of its downstream pro-inflammatory mediators.

CycC1;1-WRKY75 complex-mediated transcriptional regulation of SOS1 controls salt stress tolerance in Arabidopsis.

SALT OVERLY SENSITIVE1 (SOS1) is a key component of plant salt tolerance. However, how SOS1 transcription is dynamically regulated in plant response to different salinity conditions remains elusive. Here, we report that C-type Cyclin1;1 (CycC1;1) negatively regulates salt tolerance by interfering with WRKY75-mediated transcriptional activation of SOS1 in Arabidopsis (Arabidopsis thaliana). Disruption of CycC1;1 promotes SOS1 expression and salt tolerance in Arabidopsis because CycC1;1 interferes with RNA polymerase II recruitment by occupying the SOS1 promoter. Enhanced salt tolerance of the cycc1;1 mutant was completely compromised by an SOS1 mutation. Moreover, CycC1;1 physically interacts with the transcription factor WRKY75, which can bind to the SOS1 promoter and activate SOS1 expression. In contrast to the cycc1;1 mutant, the wrky75 mutant has attenuated SOS1 expression and salt tolerance, whereas overexpression of SOS1 rescues the salt sensitivity of wrky75. Intriguingly, CycC1;1 inhibits WRKY75-mediated transcriptional activation of SOS1 via their interaction. Thus, increased SOS1 expression and salt tolerance in cycc1;1 were abolished by WRKY75 mutation. Our findings demonstrate that CycC1;1 forms a complex with WRKY75 to inactivate SOS1 transcription under low salinity conditions. By contrast, under high salinity conditions, SOS1 transcription and plant salt tolerance are activated at least partially by increased WRKY75 expression but decreased CycC1;1 expression.

Forensic characteristics and genetic substructure analysis of the Handan Han population, Northern China.

We analysed the forensic characteristics and substructure of the Handan Han population based on 36 Y-STR (short tandem repeat) and Y-SNP (single nucleotide polymorphism) markers. The two most dominant haplogroups in Handan Han, O2a2b1a1a1-F8 (17.95%) and O2a2b1a2a1a (21.51%), and their abundant downstream branches, reflected the strong expansion of the precursor of the Hans in Handan. The present results enrich the forensic database and explore the genetic relationships between Handan Han and other neighbouring and/or linguistically close populations, which suggests that the current concise overview of the Han intricate substructure remains oversimplified.

Association between increased serum interleukin-8 levels and improved cognition in major depressive patients with SSRIs.

BACKGROUND: The effect of neuroinflammatory cytokines on cognitive deficits in patients with major depressive disorder (MDD) can be altered by selective serotonin reuptake inhibitors (SSRIs). This study aimed to examine serum interleukin-8 (IL-8) levels, cognitive function, and their associations in MDD patients with SSRIs. METHODS: Thirty SSRI-treated MDD patients and 101 healthy controls were recruited for this study. We examined cognitive performance using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and serum IL-8 levels using the Human Inflammatory Cytokine Cytometric Bead Array in both cases and controls. RESULTS: The RBANS test scores were significantly lower in MDD patients with SSRIs than in healthy controls after controlling for covariates (all p < 0.001). Serum levels of IL-8 were higher in MDD patients with SSRIs than in healthy controls after adjusting for covariates (F = 3.82, p = 0.05). Serum IL-8 levels were positively correlated with sub-scores of delayed memory (r = 0.37, p = 0.04) and visuospatial/constructional (r = 0.43, p = 0.02) in MDD patients with SSRIs but not in in healthy controls (delayed memory score: r = -0.12, p = 0.24; visuospatial/constructional score: r = 0.02, p = 0.81). CONCLUSIONS: Our findings suggested that increased serum IL-8 level might not only be involved in the MDD psychopathology or the use of SSRIs but also correspond to improving MDD delayed memory and visuospatial/constructional function.

Metabolic profiling integrated with pharmacokinetics to reveal the material basis of Xiaokeyinshui extract combination in the treatment of type 2 diabetes in rats.

Xiaokeyinshui extract combination (XEC), originating from a traditional Chinese formula Xiaokeyinshui (XKYS) recorded in ancient Bencao, has been reported to exert significant hypoglycemic effects. However, the chemical profiles, metabolic transformation and pharmacokinetic behavior of XEC in vivo were unclear. The research was to investigate the chemical constituents, metabolic profiles and pharmacokinetic behavior of XEC. A UPLC-QE-Orbitrap-HRMS qualification method was developed to identify the chemical constituents in XEC and xenobiotics of XEC in plasma, urine, feces and bile of rats after oral administration. A LC-MS quantification method was established and applied for the pharmacokinetic studies of major active compounds of XEC in normal and T2DM rats and Coptidis Rhizoma extracts (CRE) in T2DM rats. Fifty eight compounds in XEC and a total of 152 xenobiotics were identified in T2DM rats, including 28 prototypes and 124 metabolites. The metabolic pathways were demethylation, demethyleneization, reduction, hydroxylation, hydrolysis and subsequent binding reactions, including glucuronidation, sulfation and methylation. According to the results of chemical constituents and metabolites, 7 ingredients, including berberine, palmatine, coptisine, epiberberine, berberrubine, magnoflorine and aurantio-obtusin were suggested for markers to comparative pharmacokinetics study in normal rats and T2DM rats. Compared with normal rats, the Tmax of berberine, palmatine, coptisine, epiberberine, berberrubine and magnoflorine was significantly longer. The value of Cmax for palmatine, coptisine, epiberberine and berberrubine was significantly decreased in XEC T2DM group. The value of AUC for alkaloids was higher in diabetic rats. After oral CRE, alkaloids including berberine, palmatine, coptisine, epiberberine, berberrubine and magnoflorine could be detected in vivo. Compared with T2DM rats after oral administration of CRE, the value of Tmax and Cmax for berberine, palmatine, coptisine, epiberberine, berberrubine and magnoflorine exhibited significant differences in XEC T2DM group. This research provided an overview of the chemical profiles and metabolic profiling of XEC and elucidated the effect of diabetic state and compatibility on pharmacokinetic behaviors of active components in XEC. This research also can provide the material basis of XEC for subsequent quality control research.

[Cloning and bioinformatics analysis of ß-amyrin synthase in Dipsacus asper].

Dipsaci Radix is one of the commonly used Chinese medicinal materials in China, with a long history. It has the medicinal activities of nourishing liver and kidney, recovering from broken sinews, and treating bone fracture. Triterpenoid saponins are the main functional ingredients of Dipsacus asper. ß-Amyrin synthases(ß-AS) as a superfamily of oxidosqualene cyclases(OSCs) can catalyze the construction of the skeleton structure of oleanane-type triterpenoid saponins. There are only a few studies about the ß-AS in D. asper, and the catalytic mechanism of this enzyme remains to be explored. To enrich the information of ß-AS, according to the transcriptome sequencing results, we cloned DaWß-AS gene from D. asper into a specific vector for heterologous expression in Escherichia coli. In the meantime, real-time PCR was performed to analyze the relative expression of DaWß-AS in four different tissues of D. asper. The results of RT-qPCR showed DaWß-AS had the highest expression level in leaves. Bioinformatics results indicated that DaWß-AS had a conserved domain of PLN03012 superfamily, belonging to the cl31551 superfamily. There was no transmembrane domain or signal peptide in DaWß-AS. This study provides a scientific basis for revealing the biological pathways of triterpenoid saponins in D. asper, which will facilitate the biosynthesis of the associated saponins and afford reference for the cultivation and development of high-quality resources of D. asper.

CycC1;1 negatively modulates ABA signaling by interacting with and inhibiting ABI5 during seed germination.

Regulation of seed germination is important for plant survival and propagation. ABSCISIC ACID (ABA) INSENSITIVE5 (ABI5), the central transcription factor in the ABA signaling pathway, plays a fundamental role in the regulation of ABA-responsive gene expression during seed germination; however, how ABI5 transcriptional activation activity is regulated remains to be elucidated. Here, we report that C-type Cyclin1;1 (CycC1;1) is an ABI5-interacting partner affecting the ABA response and seed germination in Arabidopsis (Arabidopsis thaliana). The CycC1;1 loss-of-function mutant is hypersensitive to ABA, and this phenotype was rescued by mutation of ABI5. Moreover, CycC1;1 suppresses ABI5 transcriptional activation activity for ABI5-targeted genes including ABI5 itself by occupying their promoters and disrupting RNA polymerase II recruitment; thus the cycc1;1 mutant shows increased expression of ABI5 and genes downstream of ABI5. Furthermore, ABA reduces the interaction between CycC1;1 and ABI5, while phospho-mimic but not phospho-dead mutation of serine-42 in ABI5 abolishes CycC1;1 interaction with ABI5 and relieves CycC1;1 inhibition of ABI5-mediated transcriptional activation of downstream target genes. Together, our study illustrates that CycC1;1 negatively modulates the ABA response by interacting with and inhibiting ABI5, while ABA relieves the CycC1;1 interaction with and inhibition of ABI5 to activate ABI5 activity for the ABA response, thereby inhibiting seed germination.

Sleep disorder as a clinical risk factor of major depression: associated with cognitive impairment.

BACKGROUND: This research aims explored the sleep disorder (SD) role in major depressive disorder (MDD), and the SD influencing their cognition. METHODS: 372 MDD patients and 457 healthy controls (HCs) were enrolled. RESULTS: Patients increased a 38.88 times SD risk compared with HCs. In patients, visuospatial/constructional score was lower in SD than non-SD, and PSQI score was negatively associated with visuospatial/constructional score of SD. In SD and non-SD, RBANS scores were lower in MDD than HCs, excepted for visuospatial/constructional in non-SD. CONCLUSION: The SD as a MDD risk factor, has more serious visuospatial/constructional impairment alleviated via improving sleep/depression in patients.

Sulfenylation of ENOLASE2 facilitates H2O2-conferred freezing tolerance in Arabidopsis.

H2O2 affects the expression of genes that are involved in plant responses to diverse environmental stresses; however, the underlying mechanisms remain elusive. Here, we demonstrate that H2O2 enhances plant freezing tolerance through its effect on a protein product of low expression of osmotically responsive genes2 (LOS2). LOS2 is translated into a major product, cytosolic enolase2 (ENO2), and sometimes an alternative product, the transcription repressor c-Myc-binding protein (MBP-1). ENO2, but not MBP-1, promotes cold tolerance by binding the promoter of C-repeat/DRE binding factor1 (CBF1), a central transcription factor in plant cold signaling, thus activating its expression. Overexpression of CBF1 restores freezing sensitivity of a LOS2 loss-of-function mutant. Furthermore, cold-induced H2O2 increases nuclear import and transcriptional binding activity of ENO2 by sulfenylating cysteine 408 and thereby promotes its oligomerization. Collectively, our results illustrate how H2O2 activates plant cold responses by sulfenylating ENO2 and promoting its oligomerization, leading to enhanced nuclear translocation and transcriptional activation of CBF1.

Brujavanoids A-U, structurally diverse apotirucallane-type triterpenoids from Brucea javanica and their anti-inflammatory effects.

Extensive phytochemical investigation on the methanol extract of the inflorescences, twigs, and leaves of Brucea javanica led to the isolation and identification of 27 triterpenoids, including 21 previously undescribed ones, named brujavanoids A-U (1-21). Their structures were determined based on comprehensive spectroscopic analysis and single-crystal X-ray diffraction. Of these compounds, brujavanoid A (1) represents the first apotirucallane-type triterpenoid with a novel 19(10 â†’ 9)abeo motif, and brujavanoids B and C (2-3) are the first apotirucallane-type triterpenoids with a rarely occurring 14-hydorxy-15,16-epoxy fragment. All the isolates were evaluated for their anti-inflammatory effect in an LPS-activated RAW264.7 cells model. Furthermore, the most active one, brujavanoid E (5), can suppress the transcriptional expression of typical pro-inflammatory mediators and inhibit the nuclear translocation of NF-κB p65 in the LPS- activated RAW264.7 cells.

Abscisic acid facilitates phosphate acquisition through the transcription factor ABA INSENSITIVE5 in Arabidopsis.

Low phosphate (LP) in soil is a common nutrient stress that severely restricts agricultural production, but the role, if any, of the major stress phytohormone abscisic acid (ABA) in plant phosphate (Pi) starvation responses remains elusive. Here, we report that LP-induced ABA accumulation promotes Pi uptake in an ABA INSENSITIVE5 (ABI5)-dependent manner in Arabidopsis thaliana. LP significantly activated plant ABA biosynthesis, metabolism, and stress responses, suggesting a role of ABA in the plant response to Pi availability. LP-induced ABA accumulation and expression of two major high-affinity phosphate transporter genes PHOSPHATE TRANSPORTER1;1/1;4 (PHT1;1/1;4) were severely impaired in a mutant lacking BETA-GLUCOSIDASE1 (BG1), which converts conjugated ABA to active ABA, and the mutant had shorter roots and less Pi content than wild-type plants under LP conditions. Moreover, a mutant of ABI5, which encodes a central transcription factor in ABA signaling, also exhibited suppressed root elongation and had reduced Pi content under LP conditions. ABI5 facilitated Pi acquisition by activating the expression of PHT1;1 by directly binding to its promoter, while overexpression of PHT1;1 completely rescued its Pi content under LP conditions. Together, our findings illustrate a molecular mechanism by which ABA positively modulates phosphate acquisition through ABI5 in the Arabidopsis response to phosphate deficiency.

Coordination of plant growth and abiotic stress responses by tryptophan synthase ß subunit 1 through modulation of tryptophan and ABA homeostasis in Arabidopsis.

To adapt to changing environments, plants have evolved elaborate regulatory mechanisms balancing their growth with stress responses. It is currently unclear whether and how the tryptophan (Trp), the growth-related hormone auxin, and the stress hormone abscisic acid (ABA) are coordinated in this trade-off. Here, we show that tryptophan synthase ß subunit 1 (TSB1) is involved in the coordination of Trp and ABA, thereby affecting plant growth and abiotic stress responses. Plants experiencing high salinity or drought display reduced TSB1 expression, resulting in decreased Trp and auxin accumulation and thus reduced growth. In comparison with the wild type, amiR-TSB1 lines and TSB1 mutants exhibited repressed growth under non-stress conditions but had enhanced ABA accumulation and stress tolerance when subjected to salt or drought stress. Furthermore, we found that TSB1 interacts with and inhibits ß-glucosidase 1 (BG1), which hydrolyses glucose-conjugated ABA into active ABA. Mutation of BG1 in the amiR-TSB1 lines compromised their increased ABA accumulation and enhanced stress tolerance. Moreover, stress-induced H2O2 disrupted the interaction between TSB1 and BG1 by sulfenylating cysteine-308 of TSB1, relieving the TSB1-mediated inhibition of BG1 activity. Taken together, we revealed that TSB1 serves as a key coordinator of plant growth and stress responses by balancing Trp and ABA homeostasis.

Jatrophane Diterpenoids with Kv1.3 Ion Channel Inhibitory Effects from Euphorbia helioscopia.

Chemical investigation of bioactive components from the whole plant of Euphorbia helioscopia resulted in the isolation and identification of 17 new jatrophane diterpenoids, namely, heliojatrone D (1) and helioscopids A-P (2-17), along with 11 known analogues (18-28). The structural elucidation of the new diterpenoids was achieved by the comprehensive analysis of HRESIMS, NMR, and X-ray crystallographic data, as well as using electronic circular dichroism. Structurally, heliojatone D (1) is the fourth natural diterpenoid with a rare bicyclo[8.3.0]tridecane skeleton. The inhibitory effect of the isolated diterpenoids against Kv1.3 ion channels was evaluated in a human embryonic kidney 293 cell model transfected with plasmid encoding Kv1.3, resulting in the identification of a series of potent Kv1.3 ion channel inhibitors, with the most active ones (2 and 15) showing IC50 values of 0.9 µM.

Maize PHYTOMELATONIN RECEPTOR1 functions in plant tolerance to osmotic and drought stress.

Phytomelatonin is a universal signal molecule that regulates plant growth and stress responses; however, only one receptor that can directly bind with and perceive melatonin signaling has been identified so far, namely AtPMTR1/CAND2 in Arabidopsis. Whether other plants contain a similar receptor and, if so, how it functions is still unknown. In this study, we identified a new phytomelatonin receptor in the monocot maize (Zea mays), and investigated its role in plant responses to osmotic and drought stress. Using homology searching, we identified a plasma membrane-localized protein, Zm00001eb214610/ZmPMTR1, with strong binding activity to melatonin as a potential phytomelatonin receptor in maize. Overexpressing ZmPMTR1 in Arabidopsis Col-0 promoted osmotic stress tolerance, and rescued osmotic stress sensitivity of the Arabidopsis cand2-1 mutant. Furthermore, ZmPMTR1 also largely rescued defects in melatonin-induced stomatal closure in the cand2-1 mutant, thereby reducing water loss rate and increasing tolerance to drought stress. In addition, we identified a maize mutant of ZmPMTR1, EMS4-06e2fl, with a point-mutation causing premature termination of protein translation, and found that this mutant had lower leaf temperatures, increased rate of water loss, and enhanced drought stress sensitivity. Thus, we present ZmPMTR1 as the first phytomelatonin receptor to be identified and examined in a monocot plant, and our results indicate that it plays an important function in the response of maize to drought stress.