Singlet oxygen induces cell wall thickening and stomatal density reducing by transcriptome reprogramming.

Singlet oxygen (1O2) has a very short half-life of 10-5 s; however, it is a strong oxidant that causes growth arrest and necrotic lesions on plants. Its signaling pathway remains largely unknown. The Arabidopsis flu (fluorescent) mutant accumulates a high level of 1O2 and shows drastic changes in nuclear gene expression. Only two plastid proteins, EX1 (executer 1) and EX2 (executer 2), have been identified in the singlet oxygen signaling. Here, we found that the transcription factor abscisic acid insensitive 4 (ABI4) binds the promoters of genes responsive to 1O2-signals. Inactivation of the ABI4 protein in the flu/abi4 double mutant was sufficient to compromise the changes of almost all 1O2-responsive-genes and rescued the lethal phenotype of flu grown under light/dark cycles, similar to the flu/ex1/ex2 triple mutant. In addition to cell death, we reported for the first time that 1O2 also induces cell wall thickening and stomatal development defect. Contrastingly, no apparent growth arrest was observed for the flu mutant under normal light/dim light cycles, but the cell wall thickening (doubled) and stomatal density reduction (by two-thirds) still occurred. These results offer a new idea for breeding stress tolerant plants.

Changes in frailty and depressive symptoms among middle-aged and older Chinese people: a nationwide cohort study.

BACKGROUND AND AIMS: The older people bears a severe burden of disease due to frailty and depressive symptoms, however, the results of association between the two in the older Chinese people have been conflicting. Therefore, this study aimed to investigate the developmental trajectories and interactions of frailty and depressive symptoms in the Chinese middle-aged and older adults. METHODS: The study used four waves of data from 2011, 2013, 2015 and 2018 in the China Health and Retirement Longitudinal Study (CHARLS) database, focused on middle-aged and older people ≥ 45 years of age, and analyzed using latent growth models and cross-lagged models. RESULTS: The parallel latent growth model showed that the initial level of depressive symptoms had a significant positive predictive effect on the initial level of frailty. The rate of change in depressive symptoms significantly positively predicted the rate of change in frailty. The initial level of frailty had a significant positive predictive effect on the initial level of depressive symptoms, but a significant negative predictive effect on the rate of change in depressive symptoms. The rate of change in frailty had a significant positive predictive effect on the rate of change in depressive symptoms. The results of the cross-lagged analysis indicated a bidirectional causal association between frailty and depressive symptoms in the total sample population. Results for the total sample population grouped by age and gender were consistent with the total sample. CONCLUSIONS: This study recommends advancing the age of concern for frailty and depressive symptoms to middle-aged adults. Both men and women need early screening and intervention for frailty and depressive symptoms to promote healthy aging.

New caffeoyl derivatives with potent DPPH radical scavenging activity from Elephantopus tomentosus.

Eight new caffeoyl derivatives, elephantomentosides A-H (1 - 8), together with ten known ones (9 - 18), were isolated from the whole plant of Elephantopos tomentosus L. Their structures were elucidated using detailed spectroscopic analysis. Structurally, compounds 1 - 8 are composed of ß-D-glucopyranose, and almost all of the substituent positions are at the C-1' and C-4' of glucopyranose. The anti-inflammatory and antioxidant activities of all isolated compounds were evaluated in vitro. Compounds 9-10, 13-15, and 17-18 exhibited significant DPPH scavenging capacity with IC50 values in the range of 10.01-25.07 µM, in comparison with Vc (IC50, 17.98 µM).

Bidirectional causal relationship between depression and frailty: a univariate and multivariate Mendelian randomisation study.

BACKGROUND: cumulative evidence from cohort studies suggested that there were inconsistent conclusions as to whether there was a bidirectional association between depression and frailty. Therefore, this study used a bidirectional two-sample Mendelian randomisation (MR) study to investigate the causal relationship between depression and frailty. METHODS: we performed univariate and multivariate bidirectional MR analyses to assess the causal association between depression and frailty. Independent genetic variants associated with depression and frailty were selected as instrumental variables. Inverse variance weighted (IVW), MR-Egger, weighted median and weighted mode were mainly used in univariate MR analysis. Multivariate MR (MVMR) analyses used multivariable inverse variance-weighted methods to individually and jointly adjust for three potential confounders, body mass index (BMI), age at menarche (AAM) and waist-to-hip ratio (WHR, adjusted for BMI). RESULTS: univariate MR analysis showed a positive causal relationship between depression and risk of frailty (IVW, odds ratio (OR) = 1.30, 95% confidence interval (CI) = 1.23-1.37, P = 6.54E-22). Causal relationship between frailty and risk of depression (IVW, OR = 1.69, 95% CI = 1.33-2.16, P = 2.09E-05). MVMR analysis revealed that the bidirectional causal association between depression and frailty remained after adjusting for three potential confounders, BMI, AAM and WHR (adjusted for BMI), individually and in combination. CONCLUSIONS: our findings supported a causal relationship between genetically predicted depression and frailty in both directions.

Double deletion of cpxR and tolC significantly increases the susceptibility of Salmonella enterica serovar Typhimurium to colistin.

BACKGROUND: The increasing use of colistin causes a serious breach in our last line of defence against MDR Gram-negative pathogens. Our previous study showed that CpxR overexpression increases the susceptibility of acrB and cpxR double-deleted Salmonella enterica serovar Typhimurium to colistin. OBJECTIVES: To identify the mechanism of CpxAR and efflux pumps that synergistically enhance the susceptibility of S. Typhimurium to colistin. METHODS: A series of cpxR- and tolC-deleted mutants and a cpxR-complemented strain from a multidrug-susceptible standard strain of S. Typhimurium (JS) were generated in our previous study. Herein, we investigated the susceptibility of these strains to colistin through the broth microdilution method, time-kill curves and survival assays. Growth curves were measured by OD600 in LB broth, tryptone-soy broth (TSB) and M9-glucose (0.2%) minimal media. Finally, molecular mechanisms underlying the mode of action were elucidated by transcriptomic analysis. RESULTS: We found that in contrast to JS (0.8 mg/L), the MIC of colistin for JSΔtolC::kan showed a 16-fold decrease (0.05 mg/L). Notably, JSΔcpxRΔtolC and JSΔcpxRΔtolC/pcpxR were associated with a 256-fold decrease (0.0031 mg/L) compared with JS. Growth curves identified that JSΔcpxRΔtolC and JSΔcpxRΔtolC/pcpxR displayed a markedly lower growth rate and poorer adaptability. In addition, time-kill curves and survival assays showed that JSΔcpxRΔtolC and JSΔcpxRΔtolC/pcpxR were more susceptible to colistin. Lastly, double deletion of cpxR and tolC enhanced oxidative damage through promoting oxidative phosphorylation, the tricarboxylic acid (TCA) cycle and trimethylamine N-oxide (TMAO) respiration. CONCLUSIONS: Our findings revealed that double deletion of cpxR and tolC significantly increases the susceptibility of S. Typhimurium to colistin.

Structural Visualization of Septum Formation in Staphylococcus warneri Using Atomic Force Microscopy.

Cell division of Staphylococcus adopts a "popping" mechanism that mediates extremely rapid separation of the septum. Elucidating the structure of the septum is crucial for understanding this exceptional bacterial cell division mechanism. Here, the septum structure of Staphylococcus warneri was extensively characterized using high-speed time-lapse confocal microscopy, atomic force microscopy, and electron microscopy. The cells of S. warneri divide in a fast popping manner on a millisecond timescale. Our results show that the septum is composed of two separable layers, providing a structural basis for the ultrafast daughter cell separation. The septum is formed progressively toward the center with nonuniform thickness of the septal disk in radial directions. The peptidoglycan on the inner surface of double-layered septa is organized into concentric rings, which are generated along with septum formation. Moreover, this study signifies the importance of new septum formation in initiating new cell cycles. This work unravels the structural basis underlying the popping mechanism that drives S. warneri cell division and reveals a generic structure of the bacterial cell.IMPORTANCE This work shows that the septum of Staphylococcus warneri is composed of two layers and that the peptidoglycan on the inner surface of the double-layered septum is organized into concentric rings. Moreover, new cell cycles of S. warneri can be initiated before the previous cell cycle is complete. This work advances our knowledge about a basic structure of bacterial cell and provides information on the double-layered structure of the septum for bacteria that divide with the "popping" mechanism.

Aerosol and Surface Distribution of Severe Acute Respiratory Syndrome Coronavirus 2 in Hospital Wards, Wuhan, China, 2020.

To determine distribution of severe acute respiratory syndrome coronavirus 2 in hospital wards in Wuhan, China, we tested air and surface samples. Contamination was greater in intensive care units than general wards. Virus was widely distributed on floors, computer mice, trash cans, and sickbed handrails and was detected in air ≈4 m from patients.

Disrupting CD147-RAP2 interaction abrogates erythrocyte invasion by Plasmodium falciparum.

Effective vaccines against malaria caused by Plasmodium falciparum are still lacking, and the molecular mechanism of the host-parasite interaction is not fully understood. Here we demonstrate that the interaction of RAP2, a parasite-secreted rhoptry protein that functions in the parasitophorous vacuole formation stage of the invasion, and CD147 on the host erythrocyte is essential for erythrocyte invasion by P falciparum and is independent from all previously identified interactions involved. Importantly, the blockade of the CD147-RAP2 interaction by HP6H8, a humanized CD147 antibody, completely abolished the parasite invasion with both cure and preventative functions in a humanized mouse model. Together with its long half-life on human red blood cells and its safety profile in cynomolgus monkeys, HP6H8 is the first antibody that offers an advantageous approach by targeting a more conserved late-stage parasite ligand for preventing as well as treating severe malaria.

Structurally Diverse Acyl Bicyclobutanes: Valuable Strained Electrophiles.

Bicyclo[1.1.0]butanes (BCBs) are highly strained carbocycles that have emerged as versatile synthetic tools, particularly for the construction of functionalized small molecules. This work reports two efficient pathways for the rapid preparation of over 20 structurally diverse BCB ketones, encompassing simple alkyl and aryl derivatives, as well as unprecedented amino acid, dipeptide, bioisostere, and bifunctional linchpin reagents currently inaccessible using literature methods. Analogues are readily forged in two steps and in high yields from simple carboxylic acids or through unsymmetrical ketone synthesis beginning with a convenient carbonyl dication equivalent. The utility of this novel toolbox of strained electrophiles for the selective modification of proteinogenic nucleophiles is highlighted.

Abnormal Fractional Amplitude of Low-Frequency Fluctuation Changes in Patients with Monocular Blindness: A Functional Magnetic Resonance Imaging (MRI) Study.

BACKGROUND We used fractional amplitude of low-frequency fluctuation (fALFF) technology to investigate spontaneous cerebral activity in patients with monocular blindness (MB) and in healthy controls (HCs). MATERIAL AND METHODS Thirty MB patient and 15 HCs were included in this study. All subjects were scanned by resting-state functional magnetic resonance imaging (rs-fMRI). The independent sample t test and chi-squared test were applied to analyze demographics of MB patients and HCs. The 2-sample t test and receiver operating characteristic (ROC) curves were applied to identify the difference in average fALFF values between MB patients and HCs. Pearson's correlation analysis was applied to explore the relationship between the average fALFF values of brain areas and clinical behavior in the MB group. RESULTS MB patients had lower fALFF values in the left anterior cingulate and higher fALFF values in the left precuneus and right and left inferior parietal lobes than in HCs. Moreover, the mean fALFF values of MB patients in the left anterior cingulate had negative correlations with the anxiety scale score (r=-0.825, P<0.001) and the depression scale score (r=-0.871, P<0.001). CONCLUSIONS Our study found that MB patients had abnormal spontaneous activities in the visual and vision-related regions. The finding of abnormal neuronal activity helps to reveal the underlying neuropathologic mechanisms of vision loss.

Altered Brain Network Centrality in Patients with Adult Strabismus with Amblyopia: A Resting-State Functional Magnetic Resonance Imaging (fMRI) Study.

BACKGROUND The aim of this study was to explore potential changes in brain function network activity in patients with adult strabismus with amblyopia (SA) using the voxel-wise degree centrality (DC) method. MATERIAL AND METHODS We enrolled 15 patients with SA (6 males, 9 females) and 15 sex-matched healthy controls (HCs). All subjects completed resting functional magnetic resonance imaging scans. Independent-sample t tests and receiver operating characteristic (ROC) curves were used to assess DC value differences between groups, and Pearson correlation analysis was performed to evaluate correlations between DC-changed brain regions and clinical data of patients with SA. RESULTS Compared with the HC group, DC values that were lower in patients with SA included the left middle frontal gyrus and bilateral angular gyri. Increases were observed in the left fusiform gyrus, right lingual gyrus, right middle occipital gyrus, right postcentral gyrus, and left paracentral lobule. However, DC values were not correlated with clinical manifestations. ROC curve analysis showed high accuracy. CONCLUSIONS We found abnormal neural activity in specific brain regions in patients with SA. Specifically, we observed significant changes in DC values compared to HCs. These changes may be useful to identify the specific mechanisms involved in brain dysfunction in SA.

Chachezhania antarctica gen. nov., sp. nov., a novel member of the family 'Rhodobacteraceae' isolated from Antarctic seawater.

A Gram-stain-negative, aerobic, non-flagellated, rod-shaped bacterium, designated strain SM1703T, was isolated from Antarctic seawater collected near the Chinese Antarctic Great Wall Station, King George Island, West Antarctica. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1703T formed a distinct phylogenetic lineage within the family 'Rhodobacteraceae', sharing high 16S rRNA gene sequence similarity with Marivita litorea (95.5%). The strain grew at 10-37 °C (optimum, 25 °C) and with 0.5-13% (w/v) NaCl (optimum, 3-5%). The major cellular fatty acids were C19:0 cyclo ω8c, C18:1ω7c, C18:1 2-OH and C16:0 2-OH. The major polar lipids were phosphatidylglycerol, phosphatidylcholine, an unidentified aminolipid and an unidentified lipid. The genomic DNA G+C content of strain SM1703T was 64.6 mol%. Based on the results of the polyphasic characterization for strain SM1703T, it is classified as the representative of a novel species in a new genus of the family 'Rhodobacteraceae', for which the name Chachezhania antarctica gen. nov., sp. nov. is proposed. The type strain of Chachezhania antarctica is SM1703T (= MCCC 1K03470T = KCTC 62794T = CCTCC AB 2018351T).

Total Synthesis of Boletopsin 11 Enabled by Directed ortho-C(sp2)-H Arylation.

A nine-step synthesis of boletopsin 11 (1), a bioactive fungal natural product, is disclosed. Key features include a one-pot [O]-oxa-Michael cascade to establish the polyoxygenated dibenzofuran core followed by a Pd-catalyzed directed ortho-C(sp2)-H arylation to complete the fully functionalized carbon skeleton. Exploration of the latter transformation led to the discovery of an unexpected tandem ortho-C(sp2)-H arylation event, and the scope of the directed ortho-C(sp2)-H reaction was further investigated with coupling partners varying in stereoelectronic properties.

Damage to Hippocampus of Rats after Being Exposed to Infrasound.

OBJECTIVE: The objective was to observe damage of hippocampus in rats after exposure to infrasound, and to assess HSP70 expression in hippocampus. METHODS: SD rats in the experimental group were exposed to 140 dB (8 Hz) infrasound for 2 h per day for 3 days. The morphology of the hippocampus was examined by transmission electronic microscopic (TEM). Cell apoptosis was observed by TUNEL staining at 0 h, 24 h, 48 h, and 2 w after exposure. HSP70 expression was detected by immunohistochemistry (IHC) and Western blotting (WB). RESULTS: TEM showed that hippocampus was significantly damaged by exposure, and exhibited recovery 1 week after exposure. The TUNEL data showed that neuronal apoptosis after exposure was significantly higher than in the control rats at 24 h and 48 h, and the apoptotic cells decreased one week after exposure. IHC and WB showed HSP70 expression was significantly higher in the exposed rats, peaked at 24 h. CONCLUSION: Exposure to 140 dB (8 Hz) infrasound for 2 h per day for 3 days appeared to induce damage to the hippocampus of rats, based on changes in ultrastructure and increased cell apoptosis. However, recovery from the damage occurred overtime. HSP70 expression also increased after the exposure and decreased by 48.

Exploiting Host-Guest Interactions for the Synthesis of a Rod-Rod Block Copolymer with Crystalline and Liquid-Crystalline Blocks.

By making use of the host-guest interactions between the host molecule tris-o-phenylenedioxycyclotriphosphazene (TPP) and the rod-coil block copolymer (BCP) poly(ethylene oxide)-block-poly(octyl 4'-octyloxy-2-vinylbiphenyl-4-carboxylate) (PEO-b-PVBP), the supramolecular rod-rod block copolymer P(EO@TPP)-b-PVBP was constructed. It consists of a crystalline segment P(EO@TPP) with a hexagonal crystalline structure and a columnar nematic liquid-crystalline segment (PVBP). As the PVBP segments arrange themselves as columnar nematic phases, the crystalline structure of the inclusion complex P(EO@TPP), which has a smaller diameter, is destroyed. The self-assembled nanostructure is thus clearly affected by the interplay between the two blocks. On the basis of wide- and small-angle X-ray scattering analysis, we conclude that the supramolecular rod-rod BCP can self-assemble into a cylinder-in-cylinder double hexagonal structure.

MiR-200c suppresses TGF-ß signaling and counteracts trastuzumab resistance and metastasis by targeting ZNF217 and ZEB1 in breast cancer.

Resistance to trastuzumab and concomitantly distal metastasis are leading causes of mortality in HER2-positive breast cancers, the molecular basis of which remains largely unknown. Here, we generated trastuzumab-resistant breast cancer cells with increased tumorigenicity and invasiveness compared with parental cells, and observed robust epithelial-mesenchymal transition (EMT) and consistently elevated TGF-ß signaling in these cells. MiR-200c, which was the most significantly downregulated miRNA in trastuzumab-resistant cells, restored trastuzumab sensitivity and suppressed invasion of breast cancer cells by concurrently targeting ZNF217, a transcriptional activator of TGF-ß, and ZEB1, a known mediator of TGF-ß signaling. Given the reported backward inhibition of miR-200c by ZEB1, ZNF217 also exerts a feedback suppression of miR-200c via TGF-ß/ZEB1 signaling. Restoration of miR-200c, silencing of ZEB1 or ZNF217 or blockade of TGF-ß signaling increased trastuzumab sensitivity and suppressed invasiveness of breast cancer cells. Therefore, our study unraveled nested regulatory circuits of miR-200c/ZEB1 and miR-200c/ZNF217/TGF-ß/ZEB1 in synergistically promoting trastuzumab resistance and metastasis of breast cancer cells. These findings provide novel insights into the common role of EMT and related molecular machinery in mediating the malignant phenotypes of breast cancers.

The prevalence and influencing factors of frailty in patients with chronic kidney disease: a systematic review and meta-analysis.

BACKGROUND: To investigate the prevalence and influencing factors of frailty and pre-frailty in chronic kidney disease (CKD) patients and thereby provide a scientific basis for effective avoidance of frailty in patients with CKD. METHODS: PubMed, EMBASE, Web of Science, EBSCO, Cochrane Library, CNKI, VIP, CBMdisc, and Wanfang databases were searched for relevant studies published till December 31, 2021. The summary results were described as odds ratios (ORs) or standardized mean differences (SMDs) with 95% confidence intervals (CIs). A meta-analysis was performed using StataSE12.0. RESULTS: Fifteen published studies, which enrolled a total of 3294 CKD patients, met the inclusion criteria. The combined prevalence of frailty in CKD patients was 38.1% (95% CI 29.7-46.5%) and pre-frailty was 37.9% (95% CI 32.7-43.1%). The main factors influencing frailty in CKD patients were age (SMD 0.524, 95% CI 0.326-0.723), diastolic blood pressure (SMD - 0.294, 95% CI - 0.518 to - 0.071), body mass index (BMI) (SMD - 0.267, 95% CI - 0.471 to - 0.064), grip strength (SMD - 0.929, 95% CI - 1.233 to - 0.626), hemoglobin level (SMD - 0.346, 95% CI - 0.448 to - 0.243), serum albumin level (SMD - 0.533, 95% CI - 0.655 to - 0.411), Charlson Comorbidity Index (SMD 0.421, 95% CI 0.150-0.692), multiple medications (SMD 0.625, 95% CI 0.354-0.895), Mini-Mental State Examination (MMSE) score (SMD - 0.563, 95% CI - 0.846 to - 0.280), and female (OR 2.391, 95% CI 1.236-4.627). CONCLUSION: Frailty is common in CKD patients. The prevalence of frailty among CKD patients was related to age, diastolic blood pressure, BMI, grip strength, hemoglobin and serum albumin levels, Charlson Comorbidity Index, multiple medications, MMSE score, and female.

The causal relationship between sleep disturbances and the risk of frailty: a two-sample Mendelian randomization study.

OBJECTIVE: Adequate sleep is closely related to people's health. However, with increasing age, the quality of sleep worsens. At the same time, among elderly individuals, frailty is also a disturbing factor, which makes elderly individuals more vulnerable to negative factors. To explore the relationship between the two, we conducted this study. METHODS: In this paper, independent genetic variations related to insomnia, sleep duration and daytime sleepiness were selected as IVs, and related genetic tools were used to search published genome-wide association studies for a two-sample Mendelian randomization (TSMR) analysis. The inverse-variance weighted (IVW) method was used as the main Mendelian randomization analysis method. Cochran's Q test was used to test heterogeneity, MR‒Egger was used to test horizontal pleiotropy, and the MR-PRESSO test was used to remove outliers. RESULTS: According to our research, insomnia (OR = 1.10, 95% CI 1.03-1.17, P = 2.59e-97), long sleep duration (OR = 0.66, 95% CI 0.37-1.17, P = 0.02), short sleep duration (OR = 1.30, 95% CI 1.22-1.38, P = 2.23e-17) and daytime sleepiness (OR = 1.49, 95% CI 1.25-1.77, P = 0.96e-4) had a bidirectional causal relationship with frailty. CONCLUSIONS: Our research showed that there is a causal relationship between sleep disturbances and frailty. This result was obtained by a TSMR analysis, which involves the use of genetic variation as an IV to determine causal relationships between exposure and outcome. Future TSMR studies should include a larger sample for analysis.

Identifying ligands for the PHD1 finger of KDM5A through high-throughput screening.

PHD fingers are a type of chromatin reader that primarily recognize chromatin as a function of lysine methylation state. Dysregulated PHD fingers are implicated in various human diseases, including acute myeloid leukemia. Targeting PHD fingers with small molecules is considered challenging as their histone tail binding pockets are often shallow and surface-exposed. The KDM5A PHD1 finger regulates the catalytic activity of KDM5A, an epigenetic enzyme often misregulated in cancers. To identify ligands that disrupt the PHD1-histone peptide interaction, we conducted a high-throughput screen and validated hits by orthogonal methods. We further elucidated structure-activity relationships in two classes of compounds to identify features important for binding. Our investigation offers a starting point for further optimization of small molecule PHD1 ligands.

Identification and Optimization of Small Molecule Pyrazolopyrimidine TLR7 Agonists for Applications in Immuno-oncology.

Small molecule toll-like receptor (TLR) 7 agonists have gathered considerable interest as promising therapeutic agents for applications in cancer immunotherapy. Herein, we describe the development and optimization of a series of novel TLR7 agonists through systematic structure-activity relationship studies focusing on modification of the phenylpiperidine side chain. Additional refinement of ADME properties culminated in the discovery of compound 14, which displayed nanomolar reporter assay activity and favorable drug-like properties. Compound 14 demonstrated excellent in vivo pharmacokinetic/pharmacodynamic profiles and synergistic antitumor activity when administered in combination with aPD1 antibody, suggesting opportunities of employing 14 in immuno-oncology therapies with immune checkpoint blockade agents.