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The dynamic balance between tRNA supply and codon usage demand is a fundamental principle in the cellular translation economy. However, the regulation and functional consequences of this balance remain unclear. Here, we use PARIS2 interactome capture, structure modeling, conservation analysis, RNA-protein interaction analysis, and modification mapping to reveal the targets of hundreds of snoRNAs, many of which were previously considered orphans. We identify a snoRNA-tRNA interaction network that is required for global tRNA modifications, including 2'-O-methylation and others. Loss of Fibrillarin, the snoRNA-guided 2'-O-methyltransferase, induces global upregulation of tRNA fragments, a large group of regulatory RNAs. In particular, the snoRNAs D97/D133 guide the 2'-O-methylation of multiple tRNAs, especially for the amino acid methionine (Met), a protein-intrinsic antioxidant. Loss of D97/D133 snoRNAs in human HEK293 cells reduced target tRNA levels and induced codon adaptation of the transcriptome and translatome. Both single and double knockouts of D97 and D133 in HEK293 cells suppress Met-enriched proliferation-related gene expression programs, including, translation, splicing, and mitochondrial energy metabolism, and promote Met-depleted programs related to development, differentiation, and morphogenesis. In a mouse embryonic stem cell model of development, knockdown and knockout of D97/D133 promote differentiation to mesoderm and endoderm fates, such as cardiomyocytes, without compromising pluripotency, consistent with the enhanced development-related gene expression programs in human cells. This work solves a decades-old mystery about orphan snoRNAs and reveals a function of snoRNAs in controlling the codon-biased dichotomous cellular states of proliferation and development.
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Uso de Codones , ARN Nucleolar Pequeño , Humanos , Animales , Ratones , ARN Nucleolar Pequeño/genética , ARN Nucleolar Pequeño/metabolismo , Uso de Codones/genética , Células HEK293 , ARN de Transferencia/genética , CodónRESUMEN
The recent development and application of methods based on the general principle of "crosslinking and proximity ligation" (crosslink-ligation) are revolutionizing RNA structure studies in living cells. However, extracting structure information from such data presents unique challenges. Here, we introduce a set of computational tools for the systematic analysis of data from a wide variety of crosslink-ligation methods, specifically focusing on read mapping, alignment classification, and clustering. We design a new strategy to map short reads with irregular gaps at high sensitivity and specificity. Analysis of previously published data reveals distinct properties and bias caused by the crosslinking reactions. We perform rigorous and exhaustive classification of alignments and discover eight types of arrangements that provide distinct information on RNA structures and interactions. To deconvolve the dense and intertwined gapped alignments, we develop a network/graph-based tool Crosslinked RNA Secondary Structure Analysis using Network Techniques (CRSSANT), which enables clustering of gapped alignments and discovery of new alternative and dynamic conformations. We discover that multiple crosslinking and ligation events can occur on the same RNA, generating multisegment alignments to report complex high-level RNA structures and multi-RNA interactions. We find that alignments with overlapped segments are produced from potential homodimers and develop a new method for their de novo identification. Analysis of overlapping alignments revealed potential new homodimers in cellular noncoding RNAs and RNA virus genomes in the Picornaviridae family. Together, this suite of computational tools enables rapid and efficient analysis of RNA structure and interaction data in living cells.
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ARN no Traducido , ARN , Algoritmos , Análisis por Conglomerados , ARN/química , ARN/genética , ARN no Traducido/química , Análisis de Secuencia de ARN/métodos , Programas InformáticosRESUMEN
Sleep deprivation (SD) is a global public health burden, and has a detrimental role in the nervous system. Retina is an important part of the central nervous system; however, whether SD affects retinal structures and functions remains largely unknown. Herein, chronic SD mouse model indicated that loss of sleep for 4 months could result in reductions in the visual functions, but without obvious morphologic changes of the retina. Ultrastructural analysis by transmission electron microscope revealed the deterioration of mitochondria, which was accompanied with the decrease of multiple mitochondrial proteins in the retina. Mechanistically, oxidative stress was provoked by chronic SD, which could be ameliorated after rest, and thus restore retinal homeostasis. Moreover, the supplementation of two antioxidants, α-lipoic acid and N-acetyl-l-cysteine, could reduce retinal reactive oxygen species, repair damaged mitochondria, and, as a result, improve the retinal functions. Overall, this work demonstrated the essential roles of sleep in maintaining the integrity and health of the retina. More importantly, it points towards supplementation of antioxidants as an effective intervention strategy for people experiencing sleep shortages.
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Privación de Sueño , Ácido Tióctico , Humanos , Ratones , Animales , Privación de Sueño/complicaciones , Privación de Sueño/metabolismo , Estrés Oxidativo/fisiología , Antioxidantes/farmacología , Retina/metabolismo , Ácido Tióctico/farmacología , Ácido Tióctico/metabolismoRESUMEN
The anomalous Hall effect (AHE) is one of the most fascinating transport properties in condensed matter physics. However, the AHE magnitude, which mainly depends on net spin polarization and band topology, is generally small in oxides and thus limits potential applications. Here, we demonstrate a giant enhancement of AHE in a LaCoO3-induced 5d itinerant ferromagnet SrIrO3 by hydrogenation. The anomalous Hall resistivity and anomalous Hall angle, which are two of the most critical parameters in AHE-based devices, are found to increase to 62.2 µΩ·cm and 3%, respectively, showing an unprecedentedly large enhancement ratio of â¼10000%. Theoretical analysis suggests the key roles of Berry curvature in enhancing AHE. Furthermore, the hydrogenation concomitantly induces the significant elevation of Curie temperature from 75 to 160 K and 40-fold reinforcement of coercivity. Such giant regulation and very large AHE magnitude observed in SrIrO3 could pave the path for 5d oxide devices.
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Curcumin has been shown to have antitumor properties, but its low potency and bioavailability has limited its clinical application. We designed a novel curcuminoid, [1-propyl-3,5-bis(2-bromobenzylidene)-4-piperidinone] (PBPD), which has higher antitumor strength and improves bioavailability. Cell counting kit-8 was used to detect cell activity. Transwell assay was used to detect cell invasion and migration ability. Western blot and quantitative polymerase chain reaction were used to detect protein levels and their messenger RNA expression. Immunofluorescence was used to detect the protein location. PBPD significantly inhibited the proliferation of cervical cancer cells, with an IC50 value of 4.16 µM for Hela cells and 3.78 µM for SiHa cells, leading to the induction of cuproptosis. Transcriptome sequencing analysis revealed that PBPD significantly inhibited the Notch1/Recombination Signal Binding Protein for Immunoglobulin kappa J Region (RBP-J) and nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathways while upregulating ferredoxin 1 (FDX1) expression. Knockdown of Notch1 or RBP-J significantly inhibited NRF2 expression and upregulated FDX1 expression, leading to the inhibition of nicotinamide adenine dinucleotide phosphate activity and the induction of oxidative stress, which in turn activated endoplasmic reticulum stress and induced cell death. The overexpression of Notch1 or RBP-J resulted in the enrichment of RBP-J within the NRF2 promoter region, thereby stimulating NRF2 transcription. NRF2 knockdown resulted in increase in FDX1 expression, leading to cuproptosis. In addition, PBPD inhibited the acidification of tumor niche and reduced cell metabolism to inhibit cervical cancer cell invasion and migration. In conclusion, PBPD significantly inhibits the proliferation, invasion, and migration of cervical cancer cells and may be a novel potential drug candidate for treatment of cervical cancer.
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Proliferación Celular , Estrés del Retículo Endoplásmico , Factor 2 Relacionado con NF-E2 , Receptor Notch1 , Transducción de Señal , Neoplasias del Cuello Uterino , Humanos , Neoplasias del Cuello Uterino/tratamiento farmacológico , Neoplasias del Cuello Uterino/metabolismo , Neoplasias del Cuello Uterino/patología , Neoplasias del Cuello Uterino/genética , Estrés del Retículo Endoplásmico/efectos de los fármacos , Femenino , Factor 2 Relacionado con NF-E2/metabolismo , Factor 2 Relacionado con NF-E2/genética , Receptor Notch1/metabolismo , Receptor Notch1/genética , Proliferación Celular/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Curcumina/farmacología , Curcumina/análogos & derivados , Línea Celular Tumoral , Animales , Células HeLa , RatonesRESUMEN
Intussusception is a common cause of acute abdominal pain in children and the most frequent cause of intestinal obstruction in infants. Although often idiopathic, it can stem from conditions like lymphoma. This study delves into lymphoma-related intussusception in children, aiming to enhance early detection and management. A retrospective review encompassed children admitted from 2012 to 2023 with intussusception due to intestinal lymphoma. Demographic, clinical, and imaging data were meticulously extracted and analyzed. The study included 31 children in the lymphoma-related intussusception group. Contrasted with non-lymphoma-related cases, the patients of lymphoma-related intussusception were notably older (median age: 87 months vs. 18.5 months), predominantly male, and demonstrated protracted abdominal pain. Ultrasound unveiled mesenteric lymph node enlargement and distinct intra-abdominal masses; enema reduction success rates were notably diminished. Detecting lymphoma-related intussusception remains intricate. Age, prolonged symptoms, and distinctive ultrasound findings can arouse suspicion. Timely surgical intervention, based on preoperative imaging, proves pivotal for accurate diagnosis. CONCLUSION: Swift identification of lymphoma-related intussusception, distinguished by unique clinical and ultrasound features, is imperative for timely intervention and treatment. Further research is warranted to refine diagnostic approaches. WHAT IS KNOWN: ⢠Intussusception in pediatric patients can be caused by a wide spectrum of underlying diseases including lymphoma. ⢠Early Identifying the exact underlying cause of intussusception is crucial for tailored therapy, however often challenging and time-consuming. WHAT IS NEW: ⢠Lymphoma-related intussusception may present with increased abdominal fluid accumulation, intestinal obstruction, and a higher likelihood of failed reduction during enema procedures. ⢠For high-risk children, repeated ultrasound examinations or further investigations may be necessary to confirm the diagnosis.
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Intususcepción , Linfoma , Lactante , Niño , Humanos , Masculino , Femenino , Intususcepción/diagnóstico , Intususcepción/etiología , Intususcepción/terapia , Linfoma/complicaciones , Linfoma/diagnóstico , Estudios Retrospectivos , Enema/efectos adversos , Dolor Abdominal/etiología , Resultado del TratamientoRESUMEN
In order to develop new natural product-based anticancer agents, a series of 1,3,4-oxadiazole analogues based on petiolide A were prepared and evaluated for their anticancer activities by MTT method. The structures of all analogues were characterized by various spectral analyses, and B9 was further confirmed by X-ray crystallography. Among all the synthesized compounds, B1 displayed the most promising growth inhibitory effect on colon cancer cells (HCT116) with the IC50 value of 8.53 µM. Flow cytometric analysis exhibited that B1 arrested the cell cycle at G2 phase and induced apoptosis. Additionally, network pharmacology analysis calculated that B1 might target several key proteins, including AKT serine/threonine kinase 1 (AKT1), SRC proto-oncogene, non-receptor tyrosine kinase (SRC) and epidermal growth factor receptor (EGFR). Furthermore, molecular docking study indicated that B1 had potentially high binding affinity to these three target proteins. Given these results, analogue B1 could be deeply developed as potential anticancer agents.
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Corneal neovascularization (CNV) is one of the common blinding factors worldwide, leading to reduced vision or even blindness. However, current treatments such as surgical intervention and anti-VEGF agent therapy still have some shortcomings or evoke some adverse effects. Recently, SU6668, an inhibitor targeting angiogenic tyrosine kinases, has demonstrated growth inhibition of neovascularization. But the hydrophobicity and low ocular bioavailability limit its application in cornea. Hereby, we proposed the preparation of SU6668 pure nanoparticles (NanoSU6668; size ~135 nm) using a super-stable pure-nanomedicine formulation technology (SPFT), which possessed uniform particle size and excellent aqueous dispersion at 1 mg/mL. Furthermore, mesenchymal stem cell membrane vesicle (MSCm) was coated on the surface of NanoSU6668, and then conjugated with TAT cell penetrating peptide, preparing multifunctional TAT-MSCm@NanoSU6668 (T-MNS). The T-MNS at a concentration of 200 µg/mL was treated for CNV via eye drops, and accumulated in blood vessels with a high targeting performance, resulting in elimination of blood vessels and recovery of cornea transparency after 4 days of treatment. Meanwhile, drug safety test confirmed that T-MNS did not cause any damage to cornea, retina and other eye tissues. In conclusion, the T-MNS eye drop had the potential to treat CNV effectively and safely in a low dosing frequency, which broke new ground for CNV theranostics.
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Córnea , Neovascularización de la Córnea , Nanopartículas , Soluciones Oftálmicas , Neovascularización de la Córnea/tratamiento farmacológico , Animales , Nanopartículas/química , Soluciones Oftálmicas/química , Córnea/metabolismo , Córnea/efectos de los fármacos , Ratones , Inhibidores de la Angiogénesis/química , Inhibidores de la Angiogénesis/uso terapéutico , Inhibidores de la Angiogénesis/farmacología , Tamaño de la Partícula , Humanos , Masculino , Ratones Endogámicos C57BL , ConejosRESUMEN
OBJECTIVE: To analyze the clinical characteristics and types of congenital heart defect (CHD) in mild congenital anorectal malformation (CARM), namely the rectoperineal and rectovestibular fistulas. METHODS: The retrospective study of 183 patients with mild CARM was conducted with assessments of demographic information, color Doppler echocardiography results, and follow-up data. We performed an analysis of the clinical characteristics of CHD, grouping them based on sex and type of mild CARM. RESULTS: Of the 183 patients, rectoperineal fistula occurred in 133 patients (72.7%), while the frequency of CHD was 79.8% (146/183). Ventricular septal defects (VSDs) occur more frequently in patients with rectoperineal fistula compared to those with rectovestibular fistula (1.5% vs. 10%), while the opposite trend was observed for patent ductus arteriosus (PDAs) (39.8% vs. 22.0%). Additionally, males presented higher frequency of PDA (42.7% vs. 26.4%) and self-healing (6 months: 87.2% vs. 42.6%; 12 months: 91.0% vs. 63.2%) than females. However, males had a lower rate of undergoing cardiac surgery (6.4% vs. 17.6%) and a younger median diagnosis age (1 day vs. 9 days). CONCLUSION: Our study indicates that there is a necessity for meticulous cardiac assessment and follow-up in neonates diagnosed with mild CARM.
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Malformaciones Anorrectales , Conducto Arterioso Permeable , Fístula , Cardiopatías Congénitas , Recién Nacido , Masculino , Femenino , Humanos , Malformaciones Anorrectales/complicaciones , Malformaciones Anorrectales/epidemiología , Estudios Retrospectivos , Cardiopatías Congénitas/complicaciones , Cardiopatías Congénitas/diagnóstico por imagen , Cardiopatías Congénitas/epidemiologíaRESUMEN
Millimeter-wave (mmWave) communication systems leverage the directional beamforming capabilities of antenna arrays equipped at the base stations (BS) to counteract the inherent high propagation path loss characteristic of mmWave channels. In downlink mmWave transmissions, i.e., from the BS to users, distinguishing users within the same beam direction poses a significant challenge. Additionally, digital baseband precoding techniques are limited in their ability to mitigate inter-user interference within identical beam directions, representing a fundamental constraint in mmWave downlink transmissions. This study introduces an innovative analog beamforming-based interference mitigation strategy for downlink transmissions in reconfigurable intelligent surface (RIS)-assisted hybrid analog-digital (HAD) mmWave systems. This is achieved through the joint design of analog beamformers and the corresponding coefficients at both the RIS and the BS. We first present derived closed-form approximation expressions for the achievable rate performance in the proposed scenario and establish a stringent upper bound on this performance in a large number of RIS elements regimes. The exclusive use of analog beamforming in the downlink phase allows our proposed transmission algorithm to function efficiently when equipped with low-resolution analog-to-digital/digital-to-analog converters (A/Ds) at the BS. The energy efficiency of the downlink transmission is evaluated through the deployment of six-bit A/Ds and six-bit pulse-amplitude modulation (PAM) signals across varying numbers of activated RIS elements. Numerical simulation results validate the effectiveness of our proposed algorithms in comparison to various benchmark schemes.
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Schiff bases are a crucial component in various functional materials but often exhibit non-emissive behavior which significantly limits their potential applications as luminescent materials. However, traditional approaches to convert them into aggregate emitters often require intricate molecular design, tedious synthesis, and significant time and resource consumption. Herein, we present a cocrystallization-induced emission strategy that can transform non-emissive (hetero)aryl-substituted Schiff bases into green-yellow to yellow aggregate emitters via even simple grinding of a mixture of Schiff bases and 1,2,4,5-tetracyanobenzene (TCB) mixtures. The combined experimental and theoretical analysis revealed that the cocrystallization inhibits the C=N isomerization and promotes face-to-face π-π interaction, which restricts access to both the dark state and canonical intersection to ultimately induce emission. Furthermore, the induced emission enables the observation of solid-state molecular diffusion through fluorescence signals, advancing white light emission diodes, and notably, solution-processed organic light-emitting diodes based on cocrystal for the first time. This study not only highlights the potential of developing new C=N structural motifs for AIEgens but also could boost advancements in related structure motifs like C=C and N=N.
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Photoactivatable luminescent materials have garnered enormous attention in the field of intelligent responsive materials, yet their design and applications remain challenging due to the limited variety of photoactivatable motifs. In the work described herein, we discovered a new photoactivatable luminescent motif that underwent ring-flipping isomerization under UV irradiation. The emission of this motif exhibited a rapid transformation from dark yellow to bright green, accompanied by a significant enhancement of quantum yield from 1.9% to 34.2%. Experimental and theoretical studies revealed that the effective intramolecular motion (EIM) was crucial to the distinct luminescence performance between two isomers. In addition, polymers containing this motif were achieved through a one-pot alkyne polymerization, exhibiting both photofluorochromic and photo-cross-linking properties. Furthermore, multiple types of photopatterning, including luminescent encryption, fluorescent grayscale imaging, and high-resolution photolithographic patterns, were realized. This work developed a new photoactivatable luminescent motif and demonstrated its potential applications in both small molecules and macromolecules, which will help in the future design of photoactivatable luminescent materials.
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The long-range magnetic ordering in frustrated magnetic systems is stabilized by coupling magnetic moments to various degrees of freedom, for example, by enhancing magnetic anisotropy via lattice distortion. Here, the unconventional spin-lattice coupled metamagnetic properties of atomically-thin CrOCl, a van der Waals antiferromagnet with inherent magnetic frustration rooted in the staggered square lattice, are reported. Using temperature- and angle-dependent tunneling magnetoconductance (TMC), in complementary with magnetic torque and first-principles calculations, the antiferromagnetic (AFM)-to-ferrimagnetic (FiM) metamagnetic transitions (MTs) of few-layer CrOCl are revealed to be triggered by collective magnetic moment flipping rather than the established spin-flop mechanism, when external magnetic field (H) enforces a lattice reconstruction interlocked with the five-fold periodicity of the FiM phase. The spin-lattice coupled MTs are manifested by drastic jumps in TMC, which show anomalous upshifts at the transition thresholds and persist much higher above the AFM Néel temperature. While the MTs exhibit distinctive triaxial anisotropy, reflecting divergent magnetocrystalline anisotropy of the c-axis AFM ground state, the resulting FiM phase has an a-c easy plane in which the magnetization axis is freely rotated by H. At the 2D limit, such a field-tunable FiM phase may provide unique opportunities to explore exotic emergent phenomena and novel spintronics devices.
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OBJECTIVES: To evaluate AI biases and errors in estimating bone age (BA) by comparing AI and radiologists' clinical determinations of BA. METHODS: We established three deep learning models from a Chinese private dataset (CHNm), an American public dataset (USAm), and a joint dataset combining the above two datasets (JOIm). The test data CHNt (n = 1246) were labeled by ten senior pediatric radiologists. The effects of data site differences, interpretation bias, and interobserver variability on BA assessment were evaluated. The differences between the AI models' and radiologists' clinical determinations of BA (normal, advanced, and delayed BA groups by using the Brush data) were evaluated by the chi-square test and Kappa values. The heatmaps of CHNm-CHNt were generated by using Grad-CAM. RESULTS: We obtained an MAD value of 0.42 years on CHNm-CHNt; this result indicated an appropriate accuracy for the whole group but did not indicate an accurate estimation of individual BA because with a kappa value of 0.714, the agreement between AI and human clinical determinations of BA was significantly different. The features of the heatmaps were not fully consistent with the human vision on the X-ray films. Variable performance in BA estimation by different AI models and the disagreement between AI and radiologists' clinical determinations of BA may be caused by data biases, including patients' sex and age, institutions, and radiologists. CONCLUSIONS: The deep learning models outperform external validation in predicting BA on both internal and joint datasets. However, the biases and errors in the models' clinical determinations of child development should be carefully considered. KEY POINTS: ⢠With a kappa value of 0.714, clinical determinations of bone age by using AI did not accord well with clinical determinations by radiologists. ⢠Several biases, including patients' sex and age, institutions, and radiologists, may cause variable performance by AI bone age models and disagreement between AI and radiologists' clinical determinations of bone age. ⢠AI heatmaps of bone age were not fully consistent with human vision on X-ray films.
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Determinación de la Edad por el Esqueleto , Simulación por Computador , Aprendizaje Profundo , Niño , Humanos , Sesgo , Aprendizaje Profundo/normas , Radiólogos/normas , Estados Unidos , Determinación de la Edad por el Esqueleto/métodos , Determinación de la Edad por el Esqueleto/normas , Muñeca/diagnóstico por imagen , Dedos/diagnóstico por imagen , Masculino , Femenino , Preescolar , Adolescente , Variaciones Dependientes del Observador , Errores Diagnósticos , Simulación por Computador/normasRESUMEN
Bisphenol A (BPA) is a chemical used in the production of certain plastics and resins. Recent research has found that BPA can inhibit the activity of 3ß-hydroxysteroid dehydrogenase/Δ5,4-isomerases (3ß-HSDs). Whether benzene ring BPA substitutes can inhibit human, rat, and mouse gonadal 3ß-HSDs, the structure-activity relationship and the underlying mechanism remain unclear. In this study, we compared 6 benzene ring BPA substitutes to BPA in the inhibition of human, rat, and mouse gonadal 3ß-HSDs and conducted structure-activity relationship and in silico docking analysis. The inhibitory activity (IC50) of human 3ß-HSD2 in KGN cells ranged from about 0.02 µM for bisphenol H to 8.75 µM for BPA, that of rat 3ß-HSD1 in testicular microsomes ranged from 0.099 µM for bisphenol H to 31.32 µM for BPA, and that of mouse 3ß-HSD6 ranged from 0.021 µM for BPH to ineffectiveness for 100 µM BPA. These compounds acted as mixed inhibitors with LogP inversely correlated with IC50 and ΔG positively correlated with IC50 value. Docking analysis showed that these compounds bind to the steroid active site of the 3ß-HSD enzymes. In conclusion, some benzene ring BPA substitutes potently inhibit gonadal 3ß-HSD in various species, and lipophilicity and binding affinity determine their inhibitory strength.
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Benceno , Gónadas , Ratas , Ratones , Humanos , Animales , Compuestos de Bencidrilo/toxicidad , Relación Estructura-ActividadRESUMEN
A simple and efficient hydroxide-mediated SNAr rearrangement was reported to synthesize new depside derivatives containing the diaryl ether skeleton from the natural product barbatic acid. The prepared compounds were determined using 1H NMR, 13C NMR, HRMS, and X-ray crystallographic analysis and were also screened in vitro for cytotoxicity against three cancer cell lines and one normal cell line. The evaluation results showed that compound 3b possessed the best antiproliferative activity against liver cancer HepG2 cell line and low toxicity, which made it worth further study.
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Antineoplásicos , Depsidos , Depsidos/farmacología , Línea Celular Tumoral , Éter/farmacología , Antineoplásicos/química , Éteres/química , Éteres de Etila , Esqueleto , Ensayos de Selección de Medicamentos Antitumorales , Relación Estructura-Actividad , Proliferación Celular , Estructura MolecularRESUMEN
Molecular crystals with the ability to transform light energy into macroscopic mechanical motions are a promising class of materials with potential applications in actuating and photonic devices. In regard to such materials, coordination polymers that exhibit dynamic photomechanical motion, associated with a phase transition, are unknown. Herein, we report an intriguing photoactive, one-dimensional ZnII coordination polymer, 1, derived from 1,3,5-tri-4-pyridyl-1,2-ethenylbenzene and 3,5-difluorobenzoate. Single crystals of 1 under UV light irradiation exhibit rapid shrinking and bending, violent bursting-jumping, splitting, and cracking behavior. Single-crystal X-ray diffraction analysis and 1 Hâ NMR spectroscopy reveal an unusual photoinduced phase transition involving a single-crystal-to-single-crystal [2+2] cycloaddition reaction that results in photomechanical responses. Interestingly, crystals of 1, which are triclinic with space group P 1 â¾ ${P\bar{1}}$ , are transformed into a higher symmetry, monoclinic cell with space group C2/c. This process represents a rare example of symmetry enhancement upon photoirradiation. The photomechanical activity is likely due to the sudden release of stress associated with strained molecular geometries and significant solid-state molecular movement arising from cleavage and formation of chemical bonds. A composite membrane fabricated from 1 and polyvinyl alcohol (PVA) also displays interesting photomechanical behavior under UV light illumination, indicating the material's potential as a photoactuator.
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Due to its high reactivity and oxidative strength, singlet oxygen (1 O2 ) is used in a variety of fields including organic synthesis, biomedicine, photodynamic therapy and materials science. Despite its importance, the controlled trapping and release of 1 O2 is extremely challenging. Herein, we describe a one-dimensional coordination polymer, CP1, which upon irradiation with visible light, transforms 3 O2 (triplet oxygen) to 1 O2 . CP1 consists of CdII centers bridged by 9,10-bis((E)-2-(pyridin-4-yl)vinyl)anthracene ligands which undergo a [4+2] cycloaddition reaction with 1 O2 , resulting in the generation of CP1-1 O2 . Using microwave irradiation, CP1-1 O2 displays efficient release of 1 O2 , over a period of 30â s. In addition, CP1 exhibits enhanced fluorescence and has an oxygen detection limit of 97.4â ppm. Theoretical calculations reveal that the fluorescence behaviour is dominated by unique through-space conjugation. In addition to describing a highly efficient approach for the trapping and controlled release of 1 O2 , using coordination polymers, this work also provides encouragement for the development of efficient fluorescent oxygen sensors.
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Photosensitizers with aggregation-induced emission properties (AIEgens) can produce reactive oxygen species (ROS) under irradiation, showing great potential in the antibacterial field. However, due to the limited molecular skeletons, the development of AIEgens with precisely adjustable antibacterial activity is still a daunting challenge. Herein, a series of AIE nanofibers (AIE-NFs) based on the AIEgen of DTPM as the inner core and rationally designed peptides as bacterial recognition ligands (e.g., antimicrobial peptide (AMP) HHC36, ditryptophan, polyarginine, and polylysine) is developed. These AIE-NFs show precisely adjustable antibacterial behaviors simply by changing the decorated peptides, which can regulate the aggregation and inhibition of different bacteria. By mechanistic analysis, it is demonstrated that this effect can be attributed to the synergistic antibacterial activities of the ROS and the peptides. It is noteworthy that the optimized AIE-NFs, NFs-K18, can efficiently aggregate bacteria to cluster and kill four types of clinical bacteria under irradiation in vitro, inhibit the infection of methicillin-resistant Staphylococcus aureus (MRSA) and promote wound healing in vivo. To the authors' knowledge, this is the first report of AIE-NFs with precisely adjustable antibacterial activity, providing new opportunities for photodynamic therapy (PDT) treatment of infection.
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Staphylococcus aureus Resistente a Meticilina , Nanofibras , Fotoquimioterapia , Antibacterianos/química , Bacterias , Péptidos/farmacología , Fármacos Fotosensibilizantes/química , Especies Reactivas de OxígenoRESUMEN
Site-specific DNA double-strand breaks have been used to generate knock-in through the homology-dependent or -independent pathway. However, low efficiency and accompanying negative impacts such as undesirable indels or tumorigenic potential remain problematic. In this study, we present an enhanced reduced-risk genome editing strategy we named as NEO, which used either site-specific trans or cis double-nicking facilitated by four bacterial recombination factors (RecOFAR). In comparison to currently available approaches, NEO achieved higher knock-in (KI) germline transmission frequency (improving from zero to up to 10% efficiency with an average of 5-fold improvement for 8 loci) and 'cleaner' knock-in of long DNA fragments (up to 5.5 kb) into a variety of genome regions in zebrafish, mice and rats. Furthermore, NEO yielded up to 50% knock-in in monkey embryos and 20% relative integration efficiency in non-dividing primary human peripheral blood lymphocytes (hPBLCs). Remarkably, both on-target and off-target indels were effectively suppressed by NEO. NEO may also be used to introduce low-risk unrestricted point mutations effectively and precisely. Therefore, by balancing efficiency with safety and quality, the NEO method reported here shows substantial potential and improves the in vivo gene-editing strategies that have recently been developed.