Association of socioeconomic status and overactive bladder in US adults: a cross-sectional analysis of nationally representative data.

Background: Socioeconomic status inequality is an important variable in the emergence of urological diseases in humans. This study set out to investigate the association between the prevalence of overactive bladder (OAB) and the poverty income ratio (PIR) that served as a more influential indicator of socioeconomic status compared to education and occupation. Method: Data from the National Health and Nutrition Examination Survey (NHANES) conducted from 2007 to 2020 were used in this cross-sectional study. The association between the PIR and OAB was examined using weighted multivariate logistic regression and weighted restricted cubic splines (RCS). Additionally, interaction analysis was used for investigation to the connections between PIR and OAB in various covariate groups in order to confirm the stability of the results. Results: We observed a noteworthy inverse association between PIR and OAB after adjusting for potential confounding variables (OR = 0.87, 95% CI, 0.84-0.90, p < 0.0001). PIR was transformed into categorical variables, and the association held steady after that (1.0 < PIR <4.0 vs. PIR ≤ 1.0, OR = 0.70, 95% CI =0.63-0.77, p < 0.0001; PIR ≥ 4.0 vs. PIR ≤ 1.0, OR = 0.56, 95% CI =0.48-0.65, p < 0.0001). Additionally, RCS analysis showed that PIR and OAB had a negative nonlinear response relationship. Subgroup analyses showed that the inverse association between PIR and prevalence of OAB was stronger in obese than in nonobese individuals (P for interaction < 0.05). Conclusion: In our study, we observed a significant negative association between the PIR and the prevalence of OAB. In the future, PIR could be used as a reference standard to develop strategies to prevent and treat OAB.

Strigolactones alleviate the toxicity of polystyrene nanoplastics (PS-NPs) in maize (Zea mays L.).

Nanoplastics are widely used across various fields, yet their uptake can potentially exert adverse effects on plant growth and development, ultimately reducing yields. While there is growing awareness of the phytotoxicity caused by nanoplastics, our understanding of effective strategies to prevent nanoplastic accumulation in plants remains limited. This study explores the role of strigolactones (SLs) in mitigating the toxicity of polystyrene nanoplastics (PS-NPs) in Zea mays L. (maize). SLs application markedly inhibited PS-NPs accumulation in maize roots, thus enhancing the root weight, shoot weight and shoot length of maize. Physiological analysis showed that SLs application activated the activities of antioxidant defence enzymes, superoxide dismutase and catalase, to decrease the malondialdehyde content and electrolyte leakage and alleviate the accumulation of H2O2 and O2.- induced by PS-NPs in maize plants. Transcriptomic analyses revealed that SLs application induced transcriptional reprogramming by regulating the expression of genes related to MAPK, plant hormones and plant-pathogen interaction signal pathways in maize treated with PS-NPs. Notably, the expression of genes, such as ZmAUX/IAA and ZmGID1, associated with phytohormones in maize treated with PS-NPs underwent significant changes. In addition, SLs induced metabolic dynamics changes related to amino acid biosynthesis, ABC transporters, cysteine and methionine metabolism in maize treated with PS-NPs. In summary, these results strongly reveal that SLs could serve as a strategy to mitigate the accumulation and alleviate the stress of PS-NPs in maize, which appears to be a potential approach for mitigating the phytotoxicity induced by PS-NPs in maize.

Expression of ZmNAGK in tobacco enhances heat stress tolerance via activation of antioxidant-associated defense.

Heat stress severely inhibits plant growth and limits crop yields. Thus, it is crucial to identify genes that are associated with plant heat stress responses. Here, we report a maize (Zea mays L.) gene, N-acetylglutamate kinase (ZmNAGK), that positively enhances plant heat stress tolerance. The ZmNAGK expression level was significantly up-regulated by heat stress in maize plants, and ZmNAGK was found to be localized in maize chloroplasts. Phenotypic analysis showed that overexpressing of ZmNAGK enhanced the tolerance of tobacco to heat stress both in the seed germination and seedling growth stages. Further physiological analysis showed that ZmNAGK overexpression in tobacco could alleviate oxidative damages that occurred during heat stress via activation of antioxidant defense signaling. Transcriptome analysis revealed that ZmNAGK could modulate the expression of antioxidant-enzyme encoding genes, such as ascorbate peroxidase 2 (APX2) and superoxide dismutase C (SODC), and heat shock network genes. Taken together, we have identified a maize gene that can provide plants with heat tolerance through the induction of antioxidant-associated defense signaling.

Reciprocal regulation of flower induction by ELF3α and ELF3ß generated via alternative promoter usage.

Flowering is critical for sexual reproduction and fruit production. Several pear (Pyrus sp.) varieties produce few flower buds, but the underlying mechanisms are unknown. The circadian clock regulator EARLY FLOWERING3 (ELF3) serves as a scaffold protein in the evening complex that controls flowering. Here, we report that the absence of a 58-bp sequence in the 2nd intron of PbELF3 is genetically associated with the production of fewer flower buds in pear. From rapid amplification of cDNA ends sequencing results, we identified a short, previously unknown transcript from the PbELF3 locus, which we termed PbELF3ß, whose transcript level was significantly lower in pear cultivars that lacked the 58-bp region. The heterologous expression of PbELF3ß in Arabidopsis (Arabidopsis thaliana) accelerated flowering, whereas the heterologous expression of the full-length transcript PbELF3α caused late flowering. Notably, ELF3ß was functionally conserved in other plants. Deletion of the 2nd intron reduced AtELF3ß expression and caused delayed flowering time in Arabidopsis. AtELF3ß physically interacted with AtELF3α, disrupting the formation of the evening complex and consequently releasing its repression of flower induction genes such as GIGANTEA (GI). AtELF3ß had no effect in the absence of AtELF3α, supporting the idea that AtELF3ß promotes flower induction by blocking AtELF3α function. Our findings show that alternative promoter usage at the ELF3 locus allows plants to fine-tune flower induction.

Diurnal transcriptome dynamics reveal the photoperiod response of Pyrus.

Photoperiod provides a key environmental signal that controls plant growth. Plants have evolved an integrated mechanism for sensing photoperiods with internal clocks to orchestrate physiological events. This mechanism has been identified to enable timely plant growth and improve fitness. Although the components and pathways underlying photoperiod regulation have been described in many species, diurnal patterns of gene expression at the genome-wide level under different photoperiods are rarely reported in perennial fruit trees. To explore the global gene expression in response to photoperiod, pear plants were cultured under long-day (LD) and short-day (SD) conditions. A time-series transcriptomic study was implemented using LD and SD samples collected at 4 h intervals over 2 days. We identified 13,677 rhythmic genes, of which 7639 were identified under LD and 10,557 under SD conditions. Additionally, 4674 genes were differentially expressed in response to photoperiod change. We also characterized the candidate homologs of clock-associated genes in pear. Clock genes were involved in the regulation of many processes throughout the day, including photosynthesis, stress response, hormone dynamics, and secondary metabolism. Strikingly, genes within photosynthesis-related pathways were enriched in both the rhythmic and differential expression analyses. Several key candidate genes were identified to be associated with regulating photosynthesis and improving productivity under different photoperiods. The results suggest that temporal variation in gene expression should not be ignored in pear gene function research. Overall, our work expands the understanding of photoperiod regulation of plant growth, particularly by extending the research to non-model trees.

Characterization of the REVEILLE family in Rosaceae and role of PbLHY in flowering time regulation.

BACKGROUND: The circadian clock integrates endogenous and exogenous signals and regulates various physiological processes in plants. REVEILLE (RVE) proteins play critical roles in circadian clock system, especially CCA1 (CIRCADIAN CLOCK ASSOCIATED 1) and LHY (LATE ELONGATED HYPOCOTYL), which also participate in flowering regulation. However, little is known about the evolution and function of the RVE family in Rosaceae species, especially in Pyrus bretschneideri. RESULTS: In this study, we performed a genome-wide analysis and identified 51 RVE genes in seven Rosaceae species. The RVE family members were classified into two groups based on phylogenetic analysis. Dispersed duplication events and purifying selection were the main drivers of evolution in the RVE family. Moreover, the expression patterns of ten PbRVE genes were diverse in P. bretschneideri tissues. All PbRVE genes showed diurnal rhythms under light/dark cycles in P. bretschneideri leaves. Four PbRVE genes also displayed robust rhythms under constant light conditions. PbLHY, the gene with the highest homology to AtCCA1 and AtLHY in P. bretschneideri, is localized in the nucleus. Ectopic overexpression of PbLHY in Arabidopsis delayed flowering time and repressed the expression of flowering time-related genes. CONCLUSION: These results contribute to improving the understanding and functional research of RVE genes in P. bretschneideri.

Developing a competency framework for extracorporeal membrane oxygenation nurses: A qualitative study.

AIM: To develop a competency framework applicable to Chinese extracorporeal membrane oxygenation (ECMO) nurses. DESIGN: A qualitative study was performed following the consolidated criteria for reporting qualitative research. METHODS: Semi-structured interviews based on the critical incident technique were conducted among 21 ECMO care providers recruited from five well-known ECMO centres in Guangzhou, China. Interview transcripts were coded and analysed using the constant comparative method. The data collection period lasted from November 2021 to April 2022. RESULTS: A competency framework for ECMO nurses was identified. It included four domains: knowledge, skills, behaviours and attitudes, containing 33 subcompetencies and 66 items. RELEVANCE TO CLINICAL PRACTICE: This framework can be a reference for the assessment and training of ECMO nurses.

Overexpression of ZmEREBP60 enhances drought tolerance in maize.

Apetala2/ethylene response factor (AP2/ERF) family of transcription factors plays important roles in plant development and stress responses. However, few members of this family have been functionally and mechanistically characterised in maize. In this study, we characterised a member of the AP2/ERF transcription factor family, ZmEREBP60 from maize. Amino acid sequence alignment and phylogenetic analysis showed that ZmEREBP60 belongs to cluster I of the AP2/ERF family. qRT-PCR analysis indicated that ZmEREBP60 expression was highly induced by drought in the roots, coleoptiles, and leaves. Subcellular localisation analysis revealed that ZmEREBP60 was localised in the nucleus. Moreover, overexpression of ZmEREBP60 enhanced tolerance to drought stress while alleviating the drought-induced increase in H2O2 accumulation and malondialdehyde content in transgenic lines. Transcriptome analysis showed that ZmEREBP60 regulates the expression of genes involved in H2O2 catabolism, water deprivation response, and abscisic acid signalling pathway. Collectively, as a new member of the AP2/ERF transcription factor family in maize, ZmEREBP60 is a positive regulator of plant drought response.

[Effects of Emodin Derivative on Cell Cycle, Apoptosis and NF-κB Pathway in Burkitt Lymphoma Cells].

OBJECTIVE: To investigate the effect and mechanism of a novel emodin derivative YX-18 on Burkitt lymphoma (BL) cells. METHODS: MTT assay was used to detect the effect of YX-18 on the proliferation of BL cell lines CA46 and Raji. Annexin V-PE/7-AAD double staining assay was used for detecting the effect of YX-18 on the apoptosis of CA46 and Raji cells. PI/RNase staining was used to test the effect of YX-18 on CA46 and Raji cell cycle. JC-1 method was used to measure the changes of mitochondrial membrane potential after YX-18 treatment, and DAPI staining was used to detect the morphology of apoptotic cells. Western blot was used to analyze the distribution changes of NF-κB pathway protein (P65, P-P65, IκB, P-IκB) in the cytoplasm and cell nucleus, and also the expression changes of cyclin-related protein P21, CDK2, P-CDK2, Cycling D1, Cycling E1, and the apoptosis-related protein Caspase-3, Caspase-8, Caspase-9 and the proliferation-related protein C-MYC, BCL-2 by YX-18. Real-time fluorescence-quantitative PCR was used to evaluate the effects of YX-18 on mRNA levels of C-MYC and Ki-67 genes in CA46 and Raji cells, and EBNA-1 and EBER genes of EBV in Raji (EBV+) cells. RESULTS: Novel Emodin derivative YX-18 could effectively inhibit the proliferation of BL cell lines CA46 and Raji, showing a time-dependent effect (24, 48 and 72 h: rCA46=0.89, 0.75, 0.75, rRaji=0.87, 0.73, 0.64). IC50 of CA46 cells and Raji cells treated with YX-18 for 24 h was 1.77±0.04 µmol/L and 1.97±0.22µmol/L, respectively. CA46 cells and Raji cells were treated with YX-18 at concentration of 2.0 and 4.0 µmol/L for 24 h. Compared with the control group, both strains of cells showed a very significant apoptosis at the concentration of 2.0 and 4.0 µmol/L (P<0.01), showing a concentration-dependent effect (rCA46=0.99, rRaji=0.92). Moreover, the cleavaged Caspase-3, 8 and 9 proteins were activated by YX-18 into verious degrees in both two cell lines. Both the two cell lines displayed by YX-18 cell cycle arrest at G0/G1 phase (P<0.01) after exposed to YX-18 for 24 hours at the concentration of 1.0, 2.0 µmol/L in CA46 cells and at 0.5 and 1 µmol/L in Raji cells, respectively. YX-18 decreased expression level of cyclin D1, cyclin E1, CDK2, p-cdk2 proteins and increased p21Waf1/Cip1 level in CA46 and Raji cells. YX-18 significantly declined mitochondrial membrane potential in both cells at the concentration of 2.0 and 4.0 µmol/l (P<0.01) with concentration-dependent manner (rCA46=-0.96, rRaji=-0.99). Western blot tests indicated that YX-18 down-regulated nucleus P65 and intracellular cytoplasm P65, P-IκB, P-P65 protein, and upregulated intracellular IκB level with dose-dependent manner. Meanwhile, the expression level of the cell proliferation-related molecules C-MYC and BCL-2 was decreased significantly. YX-18 suppressed mRNA levels of C-MYC and Ki-67 in both cell lines, and EBNA-1 in EBV-positive Raji cells in a concentration-dependent way. CONCLUSION: The novel emodin derivative YX-18 can significantly inhibit the proliferation of Burkitt lymphoma cells, and induce the cell apoptosis and cycle arrest. The inhibitory effect of YX-18 on the proliferation of Burkitt lymphoma cells may be related with the effect of Caspase apoptosis pathway, the proliferation and apoptosis-related molecules, such as C-MYC and Ki-67, and also to the inhibition of NF-κB pathway.

Efficacy and safety of polyethylene glycol loxenatide as add-on to metformin in patients with type 2 diabetes: A multicentre, randomized, double-blind, placebo-controlled, phase 3b trial.

AIM: To assess the efficacy and safety of polyethylene glycol loxenatide (PEX168), a new glucagon-like peptide-1 receptor agonist, as an add-on to metformin therapy in Chinese patients with type 2 diabetes (T2D). MATERIALS AND METHODS: This was a multicentre, randomized, double-blind, placebo-controlled phase 3b trial. After metformin monotherapy (≥1500 mg/day) for 8 weeks or more, patients with uncontrolled T2D (HbA1c of 7.0%-10.5%) from 44 sites were randomized (1:1:1) to metformin + placebo, metformin + PEX168 100 µg, and metformin + PEX168 200 µg. The core treatment period lasted for 24 weeks, followed by a 28-week extension period. The primary endpoint was the change in HbA1c levels at week 24. The main secondary endpoint was the proportion of patients with an HbA1c of less than 7.0% at week 24. RESULTS: The least-square mean (standard error) change in HbA1c levels was significantly greater (P < .001 for superiority) in the PEX168 groups (-1.16% [0.08%] and -1.14% [0.08%] with 100 and 200 µg, respectively) than in the placebo group (0.35% [0.08%]). The proportion of patients with an HbA1c of less than 7.0% at week 24 was significantly higher in the PEX168 100 µg (37.4%) and PEX168 200 µg (40.6%) groups than in the placebo group (16.8%; both P < .001). The gastrointestinal reactions were mild; the risks of hypoglycaemia and weight gain did not increase. Anti-PEX168 antibodies were noted in less than 2% of patients. No treatment-emergent serious adverse events occurred. CONCLUSION: The subcutaneous injection of PEX168 once a week can effectively, continuously and safely improve HbA1c levels in patients with T2D when combined with metformin.

Efficacy and safety of DBPR108 monotherapy in patients with type 2 diabetes: a 12-week, randomized, double-blind, placebo-controlled, phase II clinical trial.

Objective: DBPR108, a novel dipeptidyl-peptidase-4 inhibitor, has shown great antihyperglycemic effect in animal models. This study was to evaluate the efficacy and safety of DBPR108 monotherapy in type 2 diabetes mellitus (T2DM).Methods: This was a 12-week, double-blind, placebo-controlled phase II clinical trial. The newly diagnosed or inadequately controlled untreated T2DM patients were randomized to receive 50, 100, 200 mg DBPR108 or placebo in a ratio of 1:1:1:1. The primary efficacy outcome was HbA1c change from baseline to week 12. Relevant secondary efficacy parameters and safety were assessed. The clinical trial registration is NCT04124484.Results: Overall, 271 of the 276 randomized patients, who received 50 mg (n = 68), 100 mg (n = 67), 200 mg (n = 69) DBPR108 or placebo (n = 67), were included in full analysis set. At week 12, HbA1c change from baseline was -0.04 ± 0.77 in placebo group, -0.51 ± 0.71, -0.75 ± 0.73, and -0.57 ± 0.78 (%, p < .001 vs. placebo) in 50, 100, and 200 mg DBPR108 groups, respectively. Since week 4, DBPR108 monotherapy resulted in significant improvements in secondary efficacy parameters. At end of 12-week treatment, the goal of HbA1c ≤7% was achieved in 29.85, 58.82, 55.22, and 47.83% of the patients in placebo, 50, 100, and 200 mg DBPR108 groups, respectively. The incidence of adverse events did not show significant difference between DBPR108 and placebo except mild hypoglycemia in DBPR108 200 mg group.Conclusions: The study results support DBPR108 100 mg once daily as the primary dosing regimen for T2DM patients in phase III development program.

Thr420 and Ser454 of ZmCCaMK play a crucial role in brassinosteroid-induced antioxidant defense in maize.

Calcium/calmodulin-dependent protein kinase (CCaMK) has been shown to play important roles in brassinosteroid (BR)-induced antioxidant defense and enhancing the tolerance of plants to drought stress. The autophosphorylation of CCaMK is a key step for the activation of CCaMK, thus promoting substrate phosphorylation. However, how CCaMK autophosphorylation function in BR-induced antioxidant defense is not known yet. Here, seven potential autophosphorylation sites of ZmCCaMK were identified using mass spectroscopy (liquid chromatography-tandem mass spectrometry [LC-MS/MS]) analysis. The transient gene expression analysis in maize protoplasts showed that Thr420 and Ser454 of ZmCCaMK were important for BR-induced antioxidant defense. Furthermore, Thr420 and Ser454 of ZmCCaMK were crucial for improving drought tolerance and alleviating drought induced oxidative damage of plants via overexpressing various mutant versions of ZmCCaMK in tobacco (Nicotiana tabacum). Mutations of Thr420 and Ser454 in ZmCCaMK substantially blocked the autophosphorylation and substrate phosphorylation of ZmCCaMK in vitro. Taken together, our results demonstrate that Thr420 and Ser454 of ZmCCaMK are crucial for BR-induced antioxidant defense and drought tolerance through modulating the autophosphorylation and substrate phosphorylation activities of ZmCCaMK.

[Effect of Inhibiting NCL Expression on Drug-Resistance of Chronic Myeloid Leukemia Cell Line K562 and Its Resistant Cells].

OBJECTIVE: To construct a K562 and adriamycin-resistant K562 (KAR) cell line with stably down-regulation of NCL (nucleolin) expression, and to investigate the effect of NCL down-regulation on the drug resistance in K562 and KAR cells. METHODS: K562 and KAR cells were infected with lentivirus, and stably transfected cell clones were obtained by puromycin screening. The cell proliferation was detected by MTS assay, the cell apoptosis was detected by flow cytometry, and the expression level of drug resistance related genes was detected by real-time PCR. RESULTS: The K562 and KAR cells with stable down-regulation of NCL were successfully constructed. Compared with the control group, the proliferation of K562 and KAR cells with down-regulating NCL expression decreased significantly (P ＜0.05), the apoptosis of cells increased significantly (P ＜0.05), and cell resistance to adriamycin was down-regulated. CONCLUSION: Inhibition of NCL expression may increase the sensitivity of cells to adriamycin, which may be related with the promotion of apoptosis of K562 and KAR cells.

Effect of nucleolin on adriamycin resistance via the regulation of B-cell lymphoma 2 expression in Burkitt's lymphoma cells.

Nucleolin (NCL, C23) is an important nucleocytoplasmic multifunctional protein. Due to its multifaceted profile and high expression in cancer, NCL is considered to be a marker of drug resistance associated with chemotherapy. However, the biochemical mechanisms in which NCL suppresses drug sensitivity in several cancers have yet to be fully elucidated. This study aims to explore the effect of NCL on drug sensitivity and its potential mechanism in CA46 Burkitt's lymphoma (BL) cells. CA46 BL cells were transfected with lentiviruses carrying the NCL gene (CA46-NCL-overexpression, CA46-NCL-OE), or shRNA sequences that target the endogenous NCL gene (CA46-NCL-knockdown, CA46-NCL-KD). Adriamycin (ADM) IC50 levels for CA46-NCL-overexpressed (OE), CA46-NCL-OE control (OEC), CA46-NCL-knockdown (KD), and CA46-NCL-KD control (KDC) cells were 0.68 ± 0.06 µg/ml, 0.68 ± 0.06 µg/ml, 0.68 ± 0.06 µg/ml, and 0.30 ± 0.04 µg/ml, respectively. Apoptosis rates were significantly increased following NCL KD, whereas the opposite effect was noted in OE cells. A significant reduction of B-cell lymphoma 2 (Bcl-2) mRNA and protein levels in KD cells was observed, while OE cells displayed the opposite effect. The stability of Bcl-2 mRNA was influenced by NCL levels, the half-life of which was extended after NCL-OE, whereas it was reduced in KD cells. Finally, results of RNA-immunoprecipitation assays indicated that NCL could bind to Bcl-2 mRNA in CA46 cells. Taken together, these results suggested that NCL could mediate Bcl-2 expression and stability, and thus enhance ADM resistance in CA46 BL cells.

Over-Expression of a Maize N-Acetylglutamate Kinase Gene (ZmNAGK) Improves Drought Tolerance in Tobacco.

Water deficit is a key limiting factor that affects the growth, development and productivity of crops. It is vital to understand the mechanisms by which plants respond to drought stress. Here an N-acetylglutamate kinase gene, ZmNAGK, was cloned from maize (Zea mays). ZmNAGK was expressed at high levels in maize leaves and at lower levels in root, stem, female flower and male flower. The expression of ZmNAGK was significantly induced by PEG, NaCl, ABA, brassinosteroid and H2O2. The ectopic expression of ZmNAGK in tobacco resulted in higher tolerance to drought compared to plants transformed with empty vector. Further physiological analysis revealed that overexpression of ZmNAGK could enhance the activities of antioxidant defense enzymes, and decrease malondialdehyde content and leakage of electrolyte in tobacco under drought stress. Moreover, the ZmNAGK transgenic tobacco accumulated more arginine and nitric oxide (NO) than control plants under drought stress. In addition, the ZmNAGK transgenic tobaccos activated drought responses faster than vector-transformed plants. These results indicate that ZmNAGK can play a vital role in enhancing drought tolerance by likely affecting the arginine and NO accumulation, and ZmNAGK could be involved in different strategies in response to drought stress.

Lysobacter erysipheiresistens sp. nov., an antagonist of powdery mildew, isolated from tobacco-cultivated soil.

A bacterial strain, RS-LYSO-3T, was isolated from tobacco-cultivated soil, collected near Chuxiong, Yunnan province, southwestern China. RS-LYSO-3T could effectively inhibit the invasion of powdery mildew on tobacco. The colonies of RS-LYSO-3T were pale yellow, and its cells were Gram-stain-negative and rod-shaped, with 68 mol% DNA G+C content. Gene sequence analysis for its 16S rRNA gene revealed the highest similarity (97.78 %) with that of Lysobacter spongiicolaKMM 329T. Chemotaxonomic data showed that RS-LYSO-3T possesses a quinone system with Q-8, and iso-C16 : 0, summed feature 9 and iso-C15 : 0 as the predominant fatty acids, all of which support the affiliation of RS-LYSO-3T to the genus Lysobacter. The results of DNA-DNA hybridization, physiological and biochemical tests clearly proved that RS-LYSO-3T is a representative of a novel species of the genus Lysobacter, for which the name Lysobacter erysipheresistens sp. nov. is proposed. The type strain is RS-LYSO-3T (=CCIC 23922T=JCM 31042T).

Phosphorylation of a NAC Transcription Factor by a Calcium/Calmodulin-Dependent Protein Kinase Regulates Abscisic Acid-Induced Antioxidant Defense in Maize.

Calcium/calmodulin-dependent protein kinase (CCaMK) has been shown to play an important role in abscisic acid (ABA)-induced antioxidant defense and enhance the tolerance of plants to drought stress. However, its downstream molecular events are poorly understood. Here, we identify a NAC transcription factor, ZmNAC84, in maize (Zea mays), which physically interacts with ZmCCaMK in vitro and in vivo. ZmNAC84 displays a partially overlapping expression pattern with ZmCCaMK after ABA treatment, and H2O2 is required for ABA-induced ZmNAC84 expression. Functional analysis reveals that ZmNAC84 is essential for ABA-induced antioxidant defense in a ZmCCaMK-dependent manner. Furthermore, ZmCCaMK directly phosphorylates Ser-113 of ZmNAC84 in vitro, and Ser-113 is essential for the ABA-induced stimulation of antioxidant defense by ZmCCaMK. Moreover, overexpression of ZmNAC84 in tobacco (Nicotiana tabacum) can improve drought tolerance and alleviate drought-induced oxidative damage of transgenic plants. These results define a mechanism for ZmCCaMK function in ABA-induced antioxidant defense, where ABA-produced H2O2 first induces expression of ZmCCaMK and ZmNAC84 and activates ZmCCaMK. Subsequently, the activated ZmCCaMK phosphorylates ZmNAC84 at Ser-113, thereby inducing antioxidant defense by activating downstream genes.

ABA Affects Brassinosteroid-Induced Antioxidant Defense via ZmMAP65-1a in Maize Plants.

Brassinosteroids (BRs) and ABA co-ordinately regulate water deficit tolerance in maize leaves. ZmMAP65-1a, a maize microtubule-associated protein (MAP) which plays an essential role in BR-induced antioxidant defense, has been characterized previously. However, the interactions among BR, ABA and ZmMAP65-1a in water deficit tolerance remain unexplored. In this study, we demonstrated that ABA was required for BR-induced antioxidant defense via ZmMAP65-1a by using biochemical blocking and ABA biosynthetic mutants. The expression of ZmMAP65-1a in maize leaves and mesophyll protoplasts could be increased under polyethylene glycol- (PEG) stimulated water deficit and ABA treatments. Furthermore, the importance of ABA in the early pathway of BR-induced water deficit tolerance was demonstrated by limiting ABA availability. Blocking ABA biosynthesis biochemically or by a null mutation inhibited the downstream gene expression of ZmMAP65-1a and the activity of ZmMAPK5 in the pathway. It also affected the activities of BR-induced antioxidant defense-related enzymes, namely ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR), superoxide dismutase (SOD) and NADPH oxidase. In addition, combining results from transiently overexpressed or silenced ZmMAP65-1a in mesophyll protoplasts, we discovered that ZmMAP65-1a mediated the ABA-induced gene expression and activities of APX and SOD. Surprisingly, silencing of ZmMAP65-1a in mesophyll protoplasts did not alter the gene expression of ZmCCaMK and vice versa in response to ABA. Taken together, our data indicate that water deficit-induced ABA is a key mediator in BR-induced antioxidant defense via ZmMAP65-1a in maize.

Calorie restriction inhibits ovarian follicle development and follicle loss through activating SIRT1 signaling in mice.

BACKGROUND: Silent information regulator 2 related enzyme 1 (SIRT1) is one of the key factors in the mechanism of calorie restriction (CR) extending lifespan of animals. The aim of the study is to investigate if CR prolongs ovarian lifespan in mice through activating SIRT1 signaling. METHODS: In the present study, 21 female C57BL/6 mice were divided into three groups: the control (n = 7), CR (n = 7), and SRT1720 (n = 7) groups. After the 26-week treatment, the number of ovarian follicles at each stage was counted, and Western blot was performed. RESULTS: The number of surviving follicles in ovaries of the SRT1720 group was less than that of the CR group but more than that of the normal control (NC) group. The number of atretic follicles in the ovaries of the SRT1720 group was similar to that of the CR group but less than that of the NC group. The number of primordial follicles in the ovaries of the SRT1720 group was less than that of the CR group but more than that of the NC group. The numbers of primary follicles, secondary follicles, antral follicles, and corpora lutea in the SRT1720 group were similar to those in the CR group. Western blot analysis showed that the expression of SIRT1, SIRT6, FOXO3a, and NRF1 proteins was upregulated, and p53 was downregulated in both the CR group and the SRT1720 group compared to the control group. CONCLUSIONS: Our results indicate that CR inhibits the activation of primordial follicles and development of follicles at different stages, thus preserving the reserve of follicle pool (at least partly) through activating SIRT1 signaling.

SIRT1 activator (SRT1720) improves the follicle reserve and prolongs the ovarian lifespan of diet-induced obesity in female mice via activating SIRT1 and suppressing mTOR signaling.

BACKGROUND: The prevalence of obesity is increasing worldwide and significantly affects fertility and reproduction in both men and women. Our recent study has shown that excess body fat accelerates ovarian follicle development and follicle loss in rats. The aim of the present study is to explore the effect of SIRT1 activator SRT1720 on the reserve of ovarian follicle pool and ovarian lifespan of obese mice and the underlying mechanism associated with SIRT1 and mTOR signaling. METHODS: Adult female Kunming mice (n = 36) were randomly divided into three groups: the normal control (NC) group (n = 8), the caloric restriction (CR) group (fed 70% food of the NC group, n = 8) and the high-fat diet (HF) group (fed a rodent chow containing 20% fat, n = 20). After 4 months, the HF mice were further randomly divided into three groups: the control high-fat diet (CHF, n = 8) group (treated every day with an intraperitoneal injection of vehicle), the SRT1720 (SRT, n = 6) group (treated every other day with an intraperitoneal injection of SRT1720 (50 mg/kg)), the SRT1720 and nicotinamide (NAM, n = 6) group (treated every other day with an intraperitoneal injection of SRT1720 (50 mg/kg) and every day with an intraperitoneal injection of nicotinamide (100 mg/kg)). After 6 weeks of treatment, ovaries were harvested for histological and Western blotting analyses. RESULTS: The body weight, ovary weight and visceral fat in the SRT group were significantly lower than those in the CHF group at the end of treatment. Histological analysis showed that the SRT mice had significantly greater number and percentage of primordial follicles, but lower number and percentage of corpora lutea and atretic follicles than the CHF mice and NAM mice. Western blot analysis demonstrated that the levels of SIRT1, SIRT6, FOXO3a and NRF-1 protein expression significantly increased in the ovaries of SRT mice, whereas those of mTORC1, p-mTOR, p-p70S6K, NFκB and p53 decreased compared to the CHF and NAM mice. CONCLUSIONS: Our study suggests that SRT1720 may improve the follicle pool reserve in HF diet-induced obese female mice via activating SIRT1 signaling and suppressing mTOR signaling, thus extending the ovarian lifespan.