Comparative phylogenetic analysis of the mediator complex subunit in asparagus bean (Vigna unguiculata ssp. sesquipedialis) and its expression profile under cold stress.

BACKGROUND: The mediator complex subunits (MED) constitutes a multiprotein complex, with each subunit intricately involved in crucial aspects of plant growth, development, and responses to stress. Nevertheless, scant reports pertain to the VunMED gene within the context of asparagus bean (Vigna unguiculata ssp. sesquipedialis). Establishing the identification and exploring the responsiveness of VunMED to cold stress forms a robust foundation for the cultivation of cold-tolerant asparagus bean cultivars. RESULTS: Within this study, a comprehensive genome-wide identification of VunMED genes was executed in the asparagus bean cultivar 'Ningjiang3', resulting in the discovery of 36 distinct VunMED genes. A phylogenetic analysis encompassing 232 MED genes from diverse species, including Arabidopsis, tomatoes, soybeans, mung beans, cowpeas, and asparagus beans, underscored the highly conserved nature of MED gene sequences. Throughout evolutionary processes, each VunMED gene underwent purification and neutral selection, with the exception of VunMED19a. Notably, VunMED9/10b/12/13/17/23 exhibited structural variations discernible across four cowpea species. Divergent patterns of temporal and spatial expression were evident among VunMED genes, with a prominent role attributed to most genes during early fruit development. Additionally, an analysis of promoter cis-acting elements was performed, followed by qRT-PCR assessments on roots, stems, and leaves to gauge relative expression after exposure to cold stress and subsequent recovery. Both treatments induced transcriptional alterations in VunMED genes, with particularly pronounced effects observed in root-based genes following cold stress. Elucidating the interrelationships between subunits involved a preliminary understanding facilitated by correlation and principal component analyses. CONCLUSIONS: This study elucidates the pivotal contribution of VunMED genes to the growth, development, and response to cold stress in asparagus beans. Furthermore, it offers a valuable point of reference regarding the individual roles of MED subunits.

Silver-Coordinated Watson-Crick Pairing-Driven Three-Dimensional DNA Walker for Locus-Specific Detection of Genomic N6-Methyladenine and N4-Methylcytosine at the Single-Molecule Level.

N6-Methyladenine (6mdA) and N4-methylcytosine (4mdC) are the two most dominant DNA modifications in both prokaryotes and eukaryotes, but standard hybridization-based techniques cannot be applied for the 6mdA/4mdC assay. Herein, we demonstrate the silver-coordinated Watson-Crick pairing-driven three-dimensional (3D) DNA walker for locus-specific detection of genomic 6mdA/4mdC at the single-molecule level. 6mdA-DNA and 4mdC-DNA can selectively hybridize with the binding probes (BP1 and BP2) to form 6mdA-DNA-BP1 and 4mdC-DNA-BP2 duplexes. The 6mdA-C/4mdC-A mismatches cannot be stabilized by AgI, and thus, 18-nt BP1/BP2 cannot be extended by the catalysis of KF exonuclease. Through toehold-mediated strand displacement (TMSD), the signal probe (SP1/SP2) functionalized on the gold nanoparticles (AuNPs) can competitively bind to BP1/BP2 in 6mdA-DNA-BP1/4mdC-DNA-BP2 duplex to obtain SP1-18-nt BP1 and SP2-18-nt BP2 duplexes. The resulting DNA duplexes can act as the substrates of lambda exonuclease, leading to the cleavage of SP1/SP2 and the release of Cy3/Cy5 and 18-nt BP1/BP2. The released 18-nt BP1/BP2 can subsequently serve as the walker DNA, moving along the surface of the AuNP to activate dynamic 3D DNA walking and releasing abundant Cy3/Cy5. The released Cy3/Cy5 can be quantified by single-molecule imaging. This nanosensor exhibits high sensitivity with a limit of detection (LOD) of 9.80 × 10-15 M for 6mdA-DNA and 9.97 × 10-15 M for 4mdC-DNA. It can discriminate 6mdA-/4mdC-DNA from unmodified genomic DNAs, distinguish 0.01% 6mdA-/4mdC-DNA from excess unmethylated DNAs, and quantify 6mdA-/4mdC-DNA at specific sites in genomic DNAs of liver cancer cells and Escherichia coli plasmid cloning vector, providing a new platform for locus-specific analysis of 6mdA/4mdC in genomic DNAs.

cGAS exacerbates Schistosoma japonicum infection in a STING-type I IFN-dependent and independent manner.

Schistosomiasis, which is caused by infection with Schistosoma spp., is characterized by granuloma and fibrosis in response to egg deposition. Pattern recognition receptors are important to sense invading Schistosoma, triggering an innate immune response, and subsequently shaping adaptive immunity. Cyclic GMP-AMP synthase (cGAS) was identified as a major cytosolic DNA sensor, which catalyzes the formation of cyclic GMP-AMP (cGAMP), a critical second messenger for the activation of the adaptor protein stimulator of interferon genes (STING). The engagement of STING by cGAMP leads to the activation of TANK-binding kinase 1 (TBK1), interferon regulatory factor 3 (IRF3), and the subsequent type I interferon (IFN) response. cGAS is suggested to regulate infectious diseases, autoimmune diseases, and cancer. However, the function of cGAS in helminth infection is unclear. In this study, we found that Cgas deficiency enhanced the survival of mice infected with S. japonicum markedly, without affecting the egg load in the liver. Consistently, Cgas deletion alleviated liver pathological impairment, reduced egg granuloma formation, and decreased fibrosis severity. In contrast, Sting deletion reduced the formation of egg granulomas markedly, but not liver fibrosis. Notably, Cgas or Sting deficiency reduced the production of IFNß drastically in mice infected with S. japonicum. Intriguingly, intravenous administration of recombinant IFNß exacerbated liver damage and promoted egg granuloma formation, without affecting liver fibrosis. Clodronate liposome-mediated depletion of macrophages indicated that macrophages are the major type of cells contributing to the induction of the type I IFN response during schistosome infection. Moreover, cGAS is important for type I IFN production and phosphorylation of TBK1 and IRF3 in response to stimulation with S. japonicum egg- or adult worm-derived DNA in macrophages. Our results clarified the immunomodulatory effect of cGAS in the regulation of liver granuloma formation during S. japonicum infection, involving sensing schistosome-derived DNA and producing type I IFN. Additionally, we showed that cGAS regulates liver fibrosis in a STING-type I-IFN-independent manner.

Plasmonic Nanodiamonds.

While nitrogen-vacancy (NV) centers in diamonds have emerged as promising solid-state quantum emitters for sensing applications, the tantalizing possibility of coupling them with photonic or broadband plasmonic nanostructures to create ultrasensitive biolabels has not been fully realized. Indeed, it remains technologically challenging to create free-standing hybrid diamond-based imaging nanoprobes with enhanced brightness and high temporal resolution. Herein, we leverage the bottom-up DNA self-assembly to develop hybrid free-standing plasmonic nanodiamonds, which feature a closed plasmonic nanocavity completely encapsulating a single nanodiamond. Correlated single nanoparticle spectroscopical characterizations suggest that the plasmonic nanodiamond displays dramatically and simultaneously enhanced brightness and emission rate. We believe that they hold huge potential to serve as a stable solid-state single-photon source and could serve as a versatile platform to study nontrivial quantum effects in biological systems with enhanced spatial and temporal resolution.

Molecular Regulatory Mechanism of Exogenous Hydrogen Sulfide in Alleviating Low-Temperature Stress in Pepper Seedlings.

Pepper (Capsicum annuum L.) is sensitive to low temperatures, with low-temperature stress affecting its plant growth, yield, and quality. In this study, we analyzed the effects of exogenous hydrogen sulfide (H2S) on pepper seedlings subjected to low-temperature stress. Exogenous H2S increased the content of endogenous H2S and its synthetase activity, enhanced the antioxidant capacity of membrane lipids, and protected the integrity of the membrane system. Exogenous H2S also promoted the Calvin cycle to protect the integrity of photosynthetic organs; enhanced the photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and photosynthesis; and reduced the intercellular CO2 concentration (Ci). Moreover, the activities of superoxide dismutase, peroxidase, catalase, and anti-cyclic glutathione (ASA-GSH) oxidase were improved to decompose excess reactive oxygen species (ROS), enhance the oxidative stress and detoxification ability of pepper seedlings, and improve the resistance to low-temperature chilling injury in 'Long Yun2' pepper seedlings. In addition, the H2S scavenger hypotaurine (HT) aggravated the ROS imbalance by reducing the endogenous H2S content, partially eliminating the beneficial effects of H2S on the oxidative stress and antioxidant defense system, indicating that H2S can effectively alleviate the damage of low temperature on pepper seedlings. The results of transcriptome analysis showed that H2S could induce the MAPK-signaling pathway and plant hormone signal transduction; upregulate the expression of transcription factors WRKY22 and PTI6; induce defense genes; and activate the ethylene and gibberellin synthesis receptors ERF1, GDI2, and DELLA, enhancing the resistance to low-temperature chilling injury of pepper seedlings. The plant-pathogen interaction was also significantly enriched, suggesting that exogenous H2S also promotes the expression of genes related to plant-pathogen interaction. The results of this study provide novel insights into the molecular mechanisms and genetic modifications of H2S that mitigate the hypothermic response.

5-ALA Improves the Low Temperature Tolerance of Common Bean Seedlings through a Combination of Hormone Transduction Pathways and Chlorophyll Metabolism.

Low-temperature stress is a key factor limiting the yield and quality of the common bean. 5-aminolevulinic acid (5-ALA), an antioxidant in plants, has been shown to modulate plant cold stress responses. However, the molecular mechanisms of 5-ALA-induced physiological and chemical changes in common bean seedlings under cold stress remains unknown. This study explored the physiological and transcriptome changes of common bean seedlings in response to cold stress after 5-ALA pretreatment. Physiological results showed that exogenous 5-ALA promotes the growth of common bean plants under cold stress, increases the activity of antioxidant enzymes (superoxide dismutase: 23.8%; peroxidase: 10.71%; catalase: 9.09%) and proline content (24.24%), decreases the relative conductivity (23.83%), malondialdehyde (33.65%), and active oxygen content, and alleviates the damage caused by cold to common bean seedlings. Transcriptome analysis revealed that 214 differentially expressed genes (DEGs) participate in response to cold stress. The DEGs are mainly concentrated in indole alkaloid biosynthesis, carotenoid biosynthesis, porphyrin, and chlorophyll metabolism. It is evident that exogenous 5-ALA alters the expression of genes associated with porphyrin and chlorophyll metabolism, as well as the plant hormone signal transduction pathway, which helps to maintain the energy supply and metabolic homeostasis under low-temperature stress. The results reveal the effect that applying exogenous 5-ALA has on the cold tolerance of the common bean and the molecular mechanism of its response to cold tolerance, which provides a theoretical basis for exploring and improving plant tolerance to low temperatures.

CaSPDS, a Spermidine Synthase Gene from Pepper (Capsicum annuum L.), Plays an Important Role in Response to Cold Stress.

Spermidine synthase (SPDS) is a key enzyme in the polyamine anabolic pathway. SPDS genes help regulate plant response to environmental stresses, but their roles in pepper remain unclear. In this study, we identified and cloned a SPDS gene from pepper (Capsicum annuum L.), named CaSPDS (LOC107847831). Bioinformatics analysis indicated that CaSPDS contains two highly conserved domains: an SPDS tetramerisation domain and a spermine/SPDS domain. Quantitative reverse-transcription polymerase chain reaction results showed that CaSPDS was highly expressed in the stems, flowers, and mature fruits of pepper and was rapidly induced by cold stress. The function of CaSPDS in cold stress response was studied by silencing and overexpressing it in pepper and Arabidopsis, respectively. Cold injury was more serious and reactive oxygen species levels were greater in the CaSPDS-silenced seedlings than in the wild-type (WT) seedlings after cold treatment. Compared with the WT plants, the CaSPDS-overexpression Arabidopsis plants were more tolerant to cold stress and showed higher antioxidant enzyme activities, spermidine content, and cold-responsive gene (AtCOR15A, AtRD29A, AtCOR47, and AtKIN1) expression. These results indicate that CaSPDS plays important roles in cold stress response and is valuable in molecular breeding to enhance the cold tolerance of pepper.

Efficacy and Safety of Shortened Dual Antiplatelet Therapy in Patients Undergoing Percutaneous Coronary Intervention: A Meta-Analysis of Randomized Controlled Trials.

ABSTRACT: To update the efficacy and safety of short-term (≤3 months) dual antiplatelet therapy (DAPT) and standard (6-12 months) DAPT in patients undergoing percutaneous coronary intervention. In addition, we also explored the duration of DAPT in patients at high bleeding risk (HBR). In PubMed, Embase, and Cochrane Library, we electronically searched among all the studies from the establishment of the database to December 8, 2021, for randomized controlled trials (RCTs). Nine randomized controlled trials (45,661 patients) ultimately met the inclusion criteria. The pooled analysis revealed that, compared with standard DAPT, ≤3-month DAPT significantly reduced major adverse cardiovascular event {hazard ratio (HR) = 0.89, 95% confidence interval (CI) [0.82-0.97]}, all-cause mortality [HR = 0.88, 95% CI (0.78-0.99)], cardiovascular mortality [HR = 0.79, 95% CI (0.65-0.97)], major bleeding [HR = 0.72, 95% CI (0.56-0.93)], and any bleeding [HR = 0.57, 95% CI (0.50-0.66)], while no significant differences in the risk of myocardial infarction, stent thrombosis, and stroke. In patients with HBR, the results showed that ≤3-month DAPT significantly reduced major bleeding [HR = 0.35, 95% CI (0.14-0.88)] and any bleeding [HR = 0.53, 95% CI (0.41-0.67)] compared with standard DAPT, while the risk of other outcomes was not statistically different. In conclusion, this study showed that ≤3-month DAPT may be a valid option for most patients after percutaneous coronary intervention. Because reductions in major adverse cardiovascular event, all-cause mortality, and cardiovascular mortality were not seen in patients with HBR, this also highlights the need for specific studies in these patients about optimal duration of antiplatelet therapy.

Genome-Wide Identification of Polyamine Oxidase (PAO) Family Genes: Roles of CaPAO2 and CaPAO4 in the Cold Tolerance of Pepper (Capsicum annuum L.).

Polyamine oxidases (PAOs), which are flavin adenine dinucleotide-dependent enzymes, catalyze polyamine (PA) catabolism, producing hydrogen peroxide (H2O2). Several PAO family members have been identified in plants, but their expression in pepper plants remains unclear. Here, six PAO genes were identified in the 'Zunla-1' pepper genome (named CaPAO1-CaPAO6 according to their chromosomal positions). The PAO proteins were divided into four subfamilies according to phylogenetics: CaPAO1 belongs to subfamily I; CaPAO3 and CaPAO5 belong to subfamily III; and CaPAO2, CaPAO4, and CaPAO6 belong to subfamily IV (none belong to subfamily II). CaPAO2, CaPAO4, and CaPAO6 were ubiquitously and highly expressed in all tissues, CaPAO1 was mainly expressed in flowers, whereas CaPAO3 and CaPAO5 were expressed at very low levels in all tissues. RNA-seq analysis revealed that CaPAO2 and CaPAO4 were notably upregulated by cold stress. CaPAO2 and CaPAO4 were localized in the peroxisome, and spermine was the preferred substrate for PA catabolism. CaPAO2 and CaPAO4 overexpression in Arabidopsis thaliana significantly enhanced freezing-stress tolerance by increasing antioxidant enzyme activity and decreasing malondialdehyde, H2O2, and superoxide accumulation, accompanied by the upregulation of cold-responsive genes (AtCOR15A, AtRD29A, AtCOR47, and AtKIN1). Thus, we identified candidate PAO genes for breeding cold-stress-tolerant transgenic pepper cultivars.

Fractal Nanoplasmonic Labels for Supermultiplex Imaging in Single Cells.

The rapidly increasing need for systems biology stimulates the development of supermultiplex (SM) methods for simultaneously labeling multiple biomolecules/cells with distinct colors. Here we report the development of DNA-engineered fractal nanoplasmonic labels with ultrahigh brightness and photostability for SM imaging in single cells. These color-resolvable nanoplasmonic labels have a uniform size of ∼50 nm with an inner hollow gap of ∼1 nm. The outer shell morphology is highly tunable with the tip aspect ratio covering the range of δ = 0.29-1.66, which supports SM plasmonic imaging exceeding the conventional fluorescence multiplexing limit. We demonstrate the use of these SM labels for quantitative imaging of receptor-mediated endocytosis and intracellular transport of multiple protein-NP structures in a single cell in real time. This SM-plasmonic method sheds light on elucidating complex interactions among protein-NPs in nanotoxicology and facilitates the development of novel nanomedicines for diagnosis and therapy.

[A modified method for spermatogonial cell sorting].

OBJECTIVE: To improve the method of sorting undifferentiated and differentiated spermatogonial cells by magnetic bead sorting with specific antibodies. METHODS: Using the magnetic bead sorting technique combined with Thy1 and c-Kit specific antibodies, we sorted Thy1+ and c-Kit+ cells in the testis of 7-postnatal-day male mice as undifferentiated and differentiated spermatogonia, respectively. We determined the purities of the two types of spermatogonial cells by immunofluorescence and flow cytometry, identified them via the differential expressions of Gfrα1, Plzf, c-Kit and Sohlh2 by real-time quantitative PCR, and cultured the Thy1+ cells primarily. RESULTS: The purities of the Thy1+ and c-kit+ cells were as high as (85.65 ± 8.35)% and (89.40 ± 2.77)%, respectively (P < 0.01). The relative expressions of the Gfrα1 and Plzf genes were 9.47 ± 1.29 and 4.40 ± 0.59 times higher in the Thy1+ than in the c-Kit+ cells, and those of the kit and sohlh2 genes 7.38 ± 1.07 and 3.88 ± 0.28 times lower in the former than in the latter (P < 0.01). After primary culture, the cells were seen in a normal state, proliferating smoothly with the characteristics of the proliferation of spermatogonial stem cells. CONCLUSIONS: The magnetic bead sorting technique with Thy1 and c-Kit specific antibodies can be used to effectively identify undifferentiated and differentiated spermatogonia and culture undifferentiated Thy1+ cells in vitro.

Promotion of neuronal regeneration by using self-polymerized dendritic polypeptide scaffold for spinal cord tissue engineering.

Tissue engineering technology is applicable for study of nerve regeneration after spinal cord injury. Many natural and artificial scaffold are not applicable because of poor mechanical properties and cell compatibility. Polypeptides with fine three-dimensional structure and cell compatibility and are widely used in tissue engineering research. The purpose of this study was to verify the neuronal differentiation of neural stem cells by using self-polymerize dendritic polypeptide for spinal cord tissue engineering. Neural stem cells were isolated from cerebral cortex of neonatal SD rats.Conventional media was triggered the 1wt% nano peptide solution self polymerizated to formed a nano gel. The gel was tested by scanning electron microscope and transmission electron microscope. Neural stem cells were inoculated onto gel or on Polylysine-coated slides with fetal bovine serum or not. SD rats were randomized divided into four groups. neural stem cells and self-polymerized peptide were transplanted into spinal cord injury models. Then we test the Density of NF-positive axons in the spinal cord injury area at 8 weeks after surgery and MS score of the locomotive function of hind limbs among mice of four groups. Neural stem cells were showed anti Nestin (+), anti NSE (+), anti GFAP (+). The gel tested by scanning electron microscope was showed thick wall structure, another one tested by transmission electron microscope was showed self-polymerized dendritic nanofibers, which contains several spacings. The cells in serum group were differentiate into neurons, but non serum group were not. These results suggest that the self-assembling peptide nanofiber scaffold(SAPNS) were cytocompatible to neural stem cells which were differentiated into neurons. A large number of axonal regeneration and recovery of joint function of hind limb were appeared. The self-polymerized Peptide maybe used as practical tissue engineering materials as future.

[Tuberous sclerosis complex with refractory epilepsy: a clinicopathologic study of 14 cases].

OBJECTIVE: To study the clinicopathologic features of tuberous sclerosis complex (TSC). METHODS: The clinicopathologic data of the patients diagnosed as TSC with refractory epilepsy and resection of epileptic focus were retrospectively analyzed. RESULTS: Fourteen cases were included, the mean age was (15.8±12.9) years, with a male predominance (male to female ratio=10:4). Frontal lobe was the most common (13/14) site of involvement. MRI showed multiple patchy long T1 and long T2 signals. CT images showed multiple subependymal high density calcified nodules in nine cases. Histology showed mild to severe disruption of the cortical lamination, cortical and subcortical tubers with giant cells and/or dysmorphic neurons. The giant cells showed strong immunoreactivity for vimentin and nestin, while the dysmorphic neurons partially expressed MAP2 and NF. Vimentin also stained strongly the "reactive" astrocytes. Thirteen cases had follow-up information: Engel class I in six cases, Engel class II in six cases, and Engel class III in one case. CONCLUSIONS: Diagnosis of TSC relies on combined pathologic, clinical and neuroradiological features. Immunohistochemical staining can be helpful. Resection of epileptic focus is an effective method to treat refractory epilepsy in TSC.

Single-particle tracking and modulation of cell entry pathways of a tetrahedral DNA nanostructure in live cells.

DNA is typically impermeable to the plasma membrane due to its polyanionic nature. Interestingly, several different DNA nanostructures can be readily taken up by cells in the absence of transfection agents, which suggests new opportunities for constructing intelligent cargo delivery systems from these biocompatible, nonviral DNA nanocarriers. However, the underlying mechanism of entry of the DNA nanostructures into the cells remains unknown. Herein, we investigated the endocytotic internalization and subsequent transport of tetrahedral DNA nanostructures (TDNs) by mammalian cells through single-particle tracking. We found that the TDNs were rapidly internalized by a caveolin-dependent pathway. After endocytosis, the TDNs were transported to the lysosomes in a highly ordered, microtubule-dependent manner. Although the TDNs retained their structural integrity within cells over long time periods, their localization in the lysosomes precludes their use as effective delivery agents. To modulate the cellular fate of the TDNs, we functionalized them with nuclear localization signals that directed their escape from the lysosomes and entry into the cellular nuclei. This study improves our understanding of the entry into cells and transport pathways of DNA nanostructures, and the results can be used as a basis for designing DNA-nanostructure-based drug delivery nanocarriers for targeted therapy.

Swallowing rehabilitation of patients undergoing T-tube implantation for the treatment of laryngotracheal stenosis.

OBJECTIVE: Patients with laryngotracheal stenosis (LTS) often have dysphagia after laryngotracheal reconstruction with T-tube insertion, which affects the quality of life. The purpose of this study is to observe the effect of swallowing rehabilitation therapy on the improvement of quality of life in patients of otolaryngology-head and neck surgery with dysphagia undergoing T-tube implantation treatment through longitudinal study. METHODS: Thirty-eight patients with LTS who experienced dysphagia after laryngotracheal reconstruction and T-tube implantation were recruited. All patients received swallowing rehabilitation therapy. The assessment of swallowing function was performed using the 10-item Eating Assessment Tool (EAT-10), the 30 mL water swallow test (WST), and flexible endoscopic evaluation of swallow (FEES). RESULTS: After swallowing rehabilitation therapy, timing of swallowing, grade of dysphagia, performance on FEES and 30 mL WST, and EAT-10 score all improved. Thirty-eight patients successfully transitioned to oral feeding and were able to remove their nasogastric tubes without experiencing any complications, including aspiration pneumonia. CONCLUSION: For patients with LTS who experienced dysphagia after laryngotracheal reconstruction and T-tube implantation, swallowing rehabilitation therapy could improve swallowing function of the patients, so as to reduce the potential harm caused by the pain and complications of surgery experienced by patients.

Label-free plasmonic spectral profiling of serum DNA.

Genetic and epigenetic modifications are linked to the activation of oncogenes and inactivation of tumor suppressor genes. Likewise, the associated molecular alternations can best inform precision medicine for personalized tumor treatment. Therefore, performing characterization of genetic and epigenetic alternations at the molecular level represents a crucial step in early diagnosis and/or therapeutics of cancer. However, the prevailing methods for DNA analysis involve a series of tedious and complicated steps, in which important genetic and epigenetic information could be lost or altered. To provide a potential approach for non-invasive, direct, and efficient DNA analysis, herein, we present a promising strategy for label-free molecular profiling of serum DNA in its pristine form by fusing surface-enhanced Raman spectroscopy with machine learning on a superior plasmonic nanostructured platform. Using DNA methylation and single-point mutation as two case studies, the presented strategy allows a well-balanced sensitive and specific detection of epigenetic and genetic changes at the single-nucleotide level in serum. We envision the presented label-free strategy could serve as a versatile tool for direct molecular profiling in pristine forms of a wide range of biological markers and aid biomedical diagnostics as well as therapeutics.

Schiff base functionalized dialdehyde starch for enhanced removal of Cu (II): Preparation, performances, DFT calculations.

Dialdehyde starch modified by 2-hydrazinopyridine (HYD-DAS) based on the reaction of dialdehyde starch (DAS) and 2-hydrazinopyridine was synthesized and characterized by FT-IR spectra, element analysis and SEM. HYD-DAS can efficiently adsorb Cu (II) ion to demonstrate visual color changes from yellow to dark brown in aqueous solutions. The influence on HYD-DAS to Cu (II) adsorption including pH value of solution, isotherm, kinetics, thermodynamics and possible mechanism had also been examined. Batch experiments indicate that HYD-DAS's to Cu (II) adsorption reaches equilibrium within 250 min, and its adsorption capacity and rate are 195.75 mg/g and 98.63 %, respectively. Moreover, HYD-DAS to Cu (II) adsorption remains robust and underscoring after five cycles to exhibit good selectivity and reusability. Kinetics studies suggest the absorption process follows a quasi-second-order with isotherms aligning to the Langmuir monolayer model, and thermodynamics reveals that it is a spontaneous endothermic nature of adsorption. Based on the analyses of XPS and DFT calculations, a possible mechanism for HYD-DAS to Cu (II) adsorption is that Cu (II) combined with nitrogen atoms from Schiff base and hydrazine pyridine ring in HYD-DAS.

A Membrane-Targeting Aggregation-Induced Emission Probe for Monitoring Lipid Droplet Dynamics in Ischemia/Reperfusion-Induced Cardiomyocyte Ferroptosis.

Myocardial ischemia/reperfusion injury (MIRI) is the leading cause of irreversible myocardial damage. A pivotal pathogenic factor is ischemia/reperfusion (I/R)-induced cardiomyocyte ferroptosis, marked by iron overload and lipid peroxidation. However, the impact of lipid droplet (LD) changes on I/R-induced cardiomyocyte ferroptosis is unclear. In this study, an aggregation-induced emission probe, TPABTBP is developed that is used for imaging dynamic changes in LD during myocardial I/R-induced ferroptosis. TPABTBP exhibits excellent LD-specificity, superior capability for monitoring lipophagy, and remarkable photostability. Molecular dynamics (MD) simulation and super-resolution fluorescence imaging demonstrate that the TPABTBP is specifically localized to the phospholipid monolayer membrane of LDs. Imaging LDs in cardiomyocytes and myocardial tissue in model mice with MIRI reveals that the LD accumulation level increase in the early reperfusion stage (0-9 h) but decrease in the late reperfusion stage (>24 h) via lipophagy. The inhibition of LD breakdown significantly reduces the lipid peroxidation level in cardiomyocytes. Furthermore, it is demonstrated that chloroquine (CQ), an FDA-approved autophagy modulator, can inhibit ferroptosis, thereby attenuating MIRI in mice. This study describes the dynamic changes in LD during myocardial ischemia injury and suggests a potential therapeutic target for early MIRI intervention.

DNA-Patched Nanoparticles for the Self-Assembly of Colloidal Metamaterials.

Colloidal metamaterials are highly desired artificial materials that recapitulate the structure of simple molecules. They exhibit exceptional functionalities conferred by the organization of and specific interaction among constituent elements. Harvesting such exquisite attributes for potential applications necessitates establishing precise control over their structural configuration with high precision. Yet, creating molecule-like small clusters of colloidal metamaterials remains profoundly challenging, as a lack of regioselectively encoded surface chemical heterogeneity prevents specific recognition interactions. Herein, we report a new strategy by harnessing magnetic-bead-assisted DNA cluster transferring to create discretely DNA cluster-patched nanoparticles for the self-assembly of colloidal metamaterials. This strategy affords broad generalizability and scalability for robustly patching DNA clusters on nanoparticles unconstrained by geometrical, dimensional, and compositional complexities commonly encountered in colloidal materials at the nano- and microscale. We direct judiciously patched nanoparticles into a wide variety of nanoassemblies and present a case study demonstrating the distinct metamaterial properties in enhancing the spontaneous emission of diamond nanoparticles. This newly invented strategy is readily implementable and extendable to construct a palette of structurally sophisticated and functionality-explicit architecture, paving the way for nanoscale manipulation of colloidal material functionalities with wide-ranging applications for biological sensing, optical engineering, and catalytic chemistry.

Pyramidal hyperbolic metasurfaces enhance spontaneous emission of nitrogen-vacancy centers in nanodiamond.

Nitrogen-vacancy (NV) centers in nanodiamond hold great promise for creating superior biological labels and quantum sensing methods. Yet, inefficient photon generation and extraction from excited NV centers restricts the achievable sensitivity and temporal resolution. Herein, we report an entirely complementary route featuring pyramidal hyperbolic metasurface to modify the spontaneous emission of NV centers. Fabricated using nanosphere lithography, the metasurface consists of alternatively stacked silica-silver thin films configured in a pyramidal fashion, and supports both spectrally broadband Purcell enhancement and spatially extended intense local fields owing to the hyperbolic dispersion and plasmonic coupling. The enhanced photophysical properties are manifested as a simultaneous amplification to the spontaneous decay rate and emission intensity of NV centers. We envision the reported pyramidal metasurface could serve as a versatile platform for creating chip-based ultrafast single-photon sources and spin-enhanced quantum biosensing strategies, as well as aiding in further fundamental understanding of photoexcited species in condensed phases.