Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 426
Filtrar
1.
J Plant Physiol ; 303: 154349, 2024 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-39260051

RESUMEN

Phosphorus deficiency usually promotes root:shoot ratio and sugar accumulation. However, how the allocation and utilization of carbon assimilates are regulated by phosphorus deficiency remains unclear. To understand how phosphorus deficiency affects the allocation and utilization of carbon assimilates, we systematically investigated the fixation and utilization of carbon, along with its diurnal and spatial patterns, in hydroponically grown maize seedlings under low phosphorus treatment. Under low phosphorus, sucrolytic activity was slightly inhibited by 12.0% in the root but dramatically inhibited by 38.8% in the shoot, corresponding to the promoted hexose/sucrose ratio and biomass in the root. Results point to a stable utilization of sucrose in the root facilitating competition for more assimilates, while increasing root:shoot ratio. Moreover, starch and sucrose accumulated in the leaves under low phosphorus. Spatially, starch and sucrose were oppositely distributed, starch mainly in the leaf tip, and sucrose mainly in the leaf base and sheath. Evidence of sucrose getting stuck in leaf base and sheath suggests that carbon accumulation is not attributed to carbon assimilation or export disturbance, but may be due to poor carbon utilization in the sinks. These findings improve the understanding of how low phosphorus regulates carbon allocation between shoot and root for acclimation to stress, and highlight the importance of improving carbon utilization in sinks to deal with phosphorus deficiency.

2.
bioRxiv ; 2024 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-39229222

RESUMEN

Electrophysiological recordings of neurons in deep brain regions using optogenetic stimulation are essential to understanding and regulating the role of complex neural activity in biological behavior and cognitive function. Optogenetic techniques have significantly advanced neuroscience research by enabling the optical manipulation of neural activities. Because of the significance of the technique, constant advancements in implantable optrodes that integrate optical stimulation with low-noise, large-scale electrophysiological recording are in demand to improve the spatiotemporal resolution for various experimental designs and future clinical applications. However, robust and easy-to-use neural optrodes that integrate neural recording arrays with high-intensity light emitting diodes (LEDs) are still lacking. Here, we propose a neural optrode based on Gallium Nitride (GaN) on sapphire technology, which integrates a high-intensity blue LED with a 5x2 recording array monolithically for simultaneous neural recording and optogenetic manipulation. To reduce the noise interference between the recording electrodes and the LED, which is in close physical proximity, three metal grounding interlayers were incorporated within the optrode, and their ability to reduce LED-induced artifacts during neural recording was confirmed through both electromagnetic simulations and experimental demonstrations. The capability of the sapphire optrode to record action potentials has been demonstrated by recording the firing of mitral/tuft cells in the olfactory bulbs of mice in vivo. Additionally, the elevation of action potential firing due to optogenetic stimulation observed using the sapphire probe in medial superior olive (MSO) neurons of the gerbil auditory brainstem confirms the capability of this sapphire optrode to precisely access neural activities in deep brain regions under complex experimental designs.

3.
Chem Biodivers ; : e202401542, 2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39193815

RESUMEN

The hypoxia-inducible factor-1α (HIF-1α) pathway has been implicated in tumor angiogenesis, growth, and metastasis. Therefore, the inhibition of this pathway is an important therapeutic target for cancer. Here, three series of panaxadiol derivatives containing a thiazole moiety (5a-l, 7a-i, and 9a-i) were synthesized and evaluated for HIF-1α inhibitory activity using a Hep3B cell-based luciferase reporter assay. Compounds 5d and 7b showed the strongest inhibitory activity with IC50 values of 17.37 and 6.42 µM, respectively, and did not show any significant cytotoxicity. Western blot assay results indicated that these two compounds exhibited more potent inhibition, compared with panaxadiol, of the expression of HIF-1α protein in Hep3B cells at a concentration of 50 µM. Molecular docking experiments were also performed to investigate the structure-activity relationship.

4.
Cell Rep ; 43(8): 114601, 2024 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-39126650

RESUMEN

Fungal pathogens such as Candida albicans pose a significant threat to human health with limited treatment options available. One strategy to expand the therapeutic target space is to identify genes important for pathogen growth in host-relevant environments. Here, we leverage a pooled functional genomic screening strategy to identify genes important for fitness of C. albicans in diverse conditions. We identify an essential gene with no known Saccharomyces cerevisiae homolog, C1_09670C, and demonstrate that it encodes subunit 3 of replication factor A (Rfa3). Furthermore, we apply computational analyses to identify functionally coherent gene clusters and predict gene function. Through this approach, we predict the cell-cycle-associated function of C3_06880W, a previously uncharacterized gene required for fitness specifically at elevated temperatures, and follow-up assays confirm that C3_06880W encodes Iml3, a component of the C. albicans kinetochore with roles in virulence in vivo. Overall, this work reveals insights into the vulnerabilities of C. albicans.


Asunto(s)
Candida albicans , Proteínas Fúngicas , Candida albicans/genética , Candida albicans/patogenicidad , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Aptitud Genética , Genómica/métodos , Virulencia/genética , Genoma Fúngico , Humanos
5.
World J Clin Cases ; 12(18): 3636-3643, 2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38983391

RESUMEN

BACKGROUND: Human herpesvirus type 7 (HHV-7) is a less common herpes virus that usually causes mild, self-limiting illnesses. However, in recent years, there have been increasing reports of HHV-7 causing serious central nervous system infections, especially meningitis. The pathogenesis and clinical features of HHV-7 meningitis, particularly in adolescents with normal immune function, remain incompletely studied. Therefore, the purpose of this report is to share a case of HHV-7 meningitis in an immunocompetent adolescent with a view to deepening our understanding of the disease. CASE SUMMARY: A 12-year-old female was admitted with fever, headache, and vomiting. 4 d before admission, the patient developed a fever without obvious induction, with a temperature up to 39.5 °C, no convulsions, accompanied by chills, headaches, fatigue, and no muscle aches. The patient was treated with fever reduction, which could be reduced to 38 °C; repeated high fever, accompanied by vomiting 7-8 times; and no abdominal pain or diarrhea. The patient was diagnosed with "acute suppurative tonsillitis" in a local hospital, and the blood routine was generally normal. The patient was given symptomatic support treatment such as "ceftriaxone sodium" and antiemetic rehydration for 2 d, and his condition did not improve. The patient's physical examination showed pharyngeal congestion, bilateral tonsil grade I hypertrophy, regression of purulent secretions, and cervical resistance. Ocular B-ultrasound: Opacity of the vitreous body and edema of the optic disc in both eyes. Optical coherence tomography examination showed that the macular fovea was generally normal in both eyes, with edema of the optic disc. DNA virus monitoring results: HHV-7. We gave ganciclovir antiviral therapy, dexamethasone anti-inflammatory treatment, mannitol to reduce cranial pressure, omeprazole to protect gastrointestinal mucosa, and calcium and potassium supplementation. CONCLUSION: This study reports a case of HHV-7 meningitis in an adolescent with normal immune function. Through comprehensive analysis of the clinical manifestations, laboratory tests, and treatment methods of the patient, it is found that early identification and antiviral treatment are essential for the outcome of the disease. This case suggests that despite normal immune function, adolescents may still suffer from herpes virus type 7 meningitis, so clinicians should be vigilant and take effective treatment measures in time.

6.
Plant Dis ; 2024 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-38916905

RESUMEN

Cigar tobacco (Nicotiana tabacum L.) is widely planted in Yunnan, which is becoming an important economic crop in China. In March 2023, root rot of cigar tobacco (cv. Yunxue 38) was observed in Baoshan (98°51'E, 24°58'N), and in July 2022 root rot of tobacco (cv. Yunyan 87) was observed in Dali (99°54'E, 26°30'N), Yunnan Province, China. The average disease incidences surveyed in the fields reached 10%. At the early stage, the bottom leaves showed wilting and turned yellow, and the roots became brown. Following the disease development, the color of roots turned to dark brown and ultimately necrosis. To isolate the causal agent, small pieces (5×5 mm) of diseased root from 6 symptomatic plant samples (three samples of cv. Yunxue 38 and three samples of cv. Yunyan 87) were cut. Pieces were surface-sterilized by dipping in 75% ethanol for 30 s, rinsed three times with sterile distilled water, then transferred to potato dextrose agar (PDA) medium and incubated at 28°C in the dark. Six fungal isolates cultured for 14 days were obtained. They were morphologically similar, so a representative isolate was selected for the following experiment. The colonies grew slowly on PDA, and their color were light pink initially, then changed to amaranth. Hyphae were hyaline and septate. Microconidia were hardly produced on PDA plates. After 14 days of culture on V8 juice agar, the colonies showed white aerial mycelia, and ellipsoidal and transparent conidia were observed, which measured 6.5 to 8.3 × 3.4 to 5.0 µm (n=20). Also, the pycnidia were measured 150 to 220 µm, that were subglobose in dark brown with brown setae. These morphological characteristics of 22DL91 were identical to S. terrestris (Boerema et al. 2004). For molecular identification, DNA was extracted and the PCR products of ITS region and polymerase II second largest subunit (RPB2), amplified with the primers ITS1/ITS4 and RPB2-5F/RPB2-7cR, were sequenced. By BLASTn analysis, the obtained ITS sequences showed 100% homology and the RPB2 sequences showed 95% homology with S. terrestris strains in GenBank (accession ON006851 and OM417590). The sequences were deposited in NCBI with accession numbers OR539491 (ITS) and OR554276 (RPB2), respectively. Based on the morphology and phylogenetic analysis, the isolate was 22DL91 identified as S. terrestris. Pathogenicity was evaluated on 50-day-old cigar tobacco seedlings (cv. Yunxue 38) and tobacco seedlings (cv. Yunyan 87). Ten plants were inoculated with 20 mL of conidial suspension of 105 conidia/mL poured onto the roots and ten control seedlings dipped in sterile water as controls (Luo et al. 2023). After 14 days, all inoculated seedlings showed the symptoms with leaves yellowing and root rot, whereas the control seedlings had no symptoms. Moreover, the fungus S. terrestris was reisolated from the infected roots, fulfilling Koch's postulates. This fungus was previously known to cause pink root on garlic in China (Zhang et al. 2019). To our knowledge, this is the first report of S. terrestris causing root rot of Nicotiana tabacum in China. Therefore, this finding will provide valuable information for prevention and management of root rot on tobacco.

7.
Artículo en Inglés | MEDLINE | ID: mdl-38829385

RESUMEN

Garlic exhibits hypolipidemic, hypoglycemic, and cardiovascular benefits. The inconsistent results of garlic preparations on adipogenesis have caused more confusion in the public and academia. The compounds responsible for the anti-adipogenesis effect of garlic remain unknown. The present study aimed to verify the real anti-adipogenesis and anti-obesity component in garlic and explored its possible effects in metabolic syndrome. We verified the real anti-adipogenesis and anti-obesity components of garlic in 3T3-L1 preadipocytes and a 10-week-high fat diet (HFD)-induced obese mice. In vitro, two water-soluble and four typical lipid-soluble compounds of garlic were tested for their anti-adipogenesis. Then, the water-soluble compound, alliin, and two processing methods produced garlic oils, were evaluated in vivo study. Mice received oral administration of alliin (25 mg/kg) and garlic oils (15 mg/kg) daily for 8 weeks. Serum lipids, parameters of obesity, and indicators involved in regulating glycolipid metabolism were examined. Our findings confirmed that both water-soluble and lipid-soluble organosulfur compounds of garlic contributed to garlic's anti-adipogenesis effect, in which water-soluble sulfides, especially alliin, exhibited greater potency. Alliin possessed potent effects of anti-obesity and improvement in glucose and lipid metabolism in HFD-induced obese mice. Alliin mediated these effects partly attributed to its modulation of enzymatic activities within glycolipid metabolism and activating PPARγ signaling pathway. In contrast to odorous lipid-soluble sulfides, alliin is odorless, stable, and safe, and is an ideal nutraceutical or even medicinal candidates for the treatment of metabolic diseases. Alliin could be used to standardize the quality of garlic products.

8.
BMC Cancer ; 24(1): 692, 2024 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-38844902

RESUMEN

BACKGROUND: Gliomas are the deadliest malignant tumors of the adult central nervous system. We previously discovered that beta2-microglobulin (B2M) is abnormally upregulated in glioma tissues and that it exerts a range of oncogenic effects. Besides its tissue presence, serum B2M levels serve as biomarkers for various diseases. This study aimed to explore whether serum B2M levels can be used in the diagnosis and prognosis of gliomas. METHODS: Medical records from 246 glioma patients were retrospectively analyzed. The relationship between preoperative serum B2M levels and clinicopathological features was examined. Kaplan-Meier analysis, alongside uni- and multivariate Cox regression, assessed the association between B2M levels, systemic inflammatory markers, and glioma patient prognosis. Receiver operating characteristic (ROC) curve analysis evaluated the diagnostic significance of these biomarkers specifically for glioblastoma (GBM). RESULTS: Patients with malignant gliomas exhibited elevated preoperative serum B2M levels. Glioma patients with high serum B2M levels experienced shorter survival times. Multivariate Cox analysis determined the relationship between B2M levels (hazard ratio = 1.92, 95% confidence interval: 1.05-3.50, P = 0.034) and the overall survival of glioma patients. B2M demonstrated superior discriminatory power in distinguishing between GBM and non-GBM compared to inflammation indicators. Moreover, postoperative serum B2M levels were lower than preoperative levels in the majority of glioma patients. CONCLUSIONS: High preoperative serum B2M levels correlated with malignant glioma and a poor prognosis. Serum B2M shows promise as a novel biomarker for predicting patient prognosis and reflecting the therapeutic response.


Asunto(s)
Biomarcadores de Tumor , Neoplasias Encefálicas , Glioma , Microglobulina beta-2 , Humanos , Microglobulina beta-2/sangre , Femenino , Masculino , Persona de Mediana Edad , Pronóstico , Biomarcadores de Tumor/sangre , Glioma/sangre , Glioma/mortalidad , Glioma/patología , Glioma/diagnóstico , Estudios Retrospectivos , Adulto , Neoplasias Encefálicas/sangre , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/diagnóstico , Anciano , Curva ROC , Estimación de Kaplan-Meier , Índice de Severidad de la Enfermedad
9.
Cell Mol Neurobiol ; 44(1): 46, 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38743119

RESUMEN

Central nervous system (CNS) disorders represent the leading cause of disability and the second leading cause of death worldwide, and impose a substantial economic burden on society. In recent years, emerging evidence has found that beta2 -microglobulin (B2M), a subunit of major histocompatibility complex class I (MHC-I) molecules, plays a crucial role in the development and progression in certain CNS diseases. On the one hand, intracellular B2M was abnormally upregulated in brain tumors and regulated tumor microenvironments and progression. On the other hand, soluble B2M was also elevated and involved in pathological stages in CNS diseases. Targeted B2M therapy has shown promising outcomes in specific CNS diseases. In this review, we provide a comprehensive summary and discussion of recent advances in understanding the pathological processes involving B2M in CNS diseases (e.g., Alzheimer's disease, aging, stroke, HIV-related dementia, glioma, and primary central nervous system lymphoma).


Asunto(s)
Enfermedades del Sistema Nervioso Central , Microglobulina beta-2 , Humanos , Microglobulina beta-2/metabolismo , Enfermedades del Sistema Nervioso Central/metabolismo , Enfermedades del Sistema Nervioso Central/patología , Animales
10.
Int J Med Sci ; 21(6): 1079-1090, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38774751

RESUMEN

Idiopathic pulmonary fibrosis (IPF) is a rare, chronic and progressively worsening lung disease that poses a significant threat to patient prognosis, with a mortality rate exceeding that of some common malignancies. Effective methods for early diagnosis and treatment remain for this condition are elusive. In our study, we used the GEO database to access second-generation sequencing data and associated clinical information from IPF patients. By utilizing bioinformatics techniques, we identified crucial disease-related genes and their biological functions, and characterized their expression patterns. Furthermore, we mapped out the immune landscape of IPF, which revealed potential roles for novel kinase 1 and CD8+T cells in disease progression and outcome. These findings can aid the development of new strategies for the clinical diagnosis and treatment of IPF.


Asunto(s)
Linfocitos T CD8-positivos , Fibrosis Pulmonar Idiopática , Humanos , Linfocitos T CD8-positivos/inmunología , Biología Computacional , Progresión de la Enfermedad , Fibrosis Pulmonar Idiopática/genética , Fibrosis Pulmonar Idiopática/inmunología , Fibrosis Pulmonar Idiopática/patología , Pronóstico
11.
Adv Mater ; 36(32): e2402628, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38670114

RESUMEN

A new nanoporous amorphous carbon (NAC) structure that achieves both ultrahigh strength and high electrical conductivity, which are usually incompatible in porous materials is reported. By using modified spark plasma sintering, three amorphous carbon phases with different atomic bonding configurations are created. The composite consisted of an amorphous sp2-carbon matrix mixed with amorphous sp3-carbon and amorphous graphitic motif. NAC structure has an isotropic electrical conductivity of up to 12 000 S m-1, Young's modulus of up to ≈5 GPa, and Vickers hardness of over 900 MPa. These properties are superior to those of existing conductive nanoporous materials. Direct investigation of the multiscale structure of this material through transmission electron microscopy, electron energy loss spectroscopy, and machine learning-based electron tomography revealed that the origin of the remarkable material properties is the well-organized sp2/sp3 amorphous carbon phases with a core-shell-like architecture, where the sp3-rich carbon forms a resilient core surrounded by a conductive sp2-rich layer. This research not only introduces novel materials with exceptional properties but also opens new opportunities for exploring amorphous structures and designing high-performance materials.

12.
Bioorg Chem ; 147: 107400, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38688196

RESUMEN

Although certain members of the Ubiquitin-specific peptidases (USPs) have been recognized as promising therapeutic targets for various diseases, research progress regarding USP21 has been relatively sluggish in its early stages. USP21 is a crucial member of the USPs subfamily, involved in diverse cellular processes such as apoptosis, DNA repair, and signal transduction. Research findings from the past decade demonstrate that USP21 mediates the deubiquitination of multiple well-known target proteins associated with critical cellular processes relevant to both disease and homeostasis, particularly in various cancers.This reviewcomprehensively summarizes the structure and biological functions of USP21 with an emphasis on its role in tumorigenesis, and elucidates the advances on the discovery of tens of small-molecule inhibitors targeting USP21, which suggests that targeting USP21 may represent a potential strategy for cancer therapy.


Asunto(s)
Neoplasias , Ubiquitina Tiolesterasa , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Neoplasias/metabolismo , Ubiquitina Tiolesterasa/antagonistas & inhibidores , Ubiquitina Tiolesterasa/metabolismo , Antineoplásicos/farmacología , Antineoplásicos/química , Animales , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/química , Estructura Molecular
13.
Mol Syst Biol ; 20(6): 719-740, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38580884

RESUMEN

Tumor suppressor p53 (TP53) is frequently mutated in cancer, often resulting not only in loss of its tumor-suppressive function but also acquisition of dominant-negative and even oncogenic gain-of-function traits. While wild-type p53 levels are tightly regulated, mutants are typically stabilized in tumors, which is crucial for their oncogenic properties. Here, we systematically profiled the factors that regulate protein stability of wild-type and mutant p53 using marker-based genome-wide CRISPR screens. Most regulators of wild-type p53 also regulate p53 mutants, except for p53 R337H regulators, which are largely private to this mutant. Mechanistically, FBXO42 emerged as a positive regulator for a subset of p53 mutants, working with CCDC6 to control USP28-mediated mutant p53 stabilization. Additionally, C16orf72/HAPSTR1 negatively regulates both wild-type p53 and all tested mutants. C16orf72/HAPSTR1 is commonly amplified in breast cancer, and its overexpression reduces p53 levels in mouse mammary epithelium leading to accelerated breast cancer. This study offers a network perspective on p53 stability regulation, potentially guiding strategies to reinforce wild-type p53 or target mutant p53 in cancer.


Asunto(s)
Mutación , Estabilidad Proteica , Proteína p53 Supresora de Tumor , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Animales , Humanos , Ratones , Femenino , Sistemas CRISPR-Cas , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Línea Celular Tumoral , Ubiquitina Tiolesterasa/genética , Ubiquitina Tiolesterasa/metabolismo , Regulación Neoplásica de la Expresión Génica , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas
14.
BMC Anesthesiol ; 24(1): 147, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38632505

RESUMEN

OBJECTIVE: The aim of this study is to observe the anesthetic effect and safety of intravenous anesthesia without muscle relaxant with propofol-remifentanil combined with regional block under laryngeal mask airway in pediatric ophthalmologic surgery. METHODS: A total of 90 undergoing ophthalmic surgery were anesthetized with general anesthesia using the laryngeal mask airway without muscle relaxant. They were randomly divided into two groups: 45 children who received propofol-remifentanil intravenous anesthesia combined with regional block (LG group), and 45 children who received total intravenous anesthesia (G group). The peri-operative circulatory indicators, awakening time after general anesthesia, postoperative analgesic effect and the incidence of anesthesia-related adverse events were respectively compared between the two groups. RESULTS: All the children successfully underwent the surgical procedure. The awakening time after general anesthesia and removal time of laryngeal mask were significantly shorter in the LG group than in the G group (P < 0.05). There was no statistically significant difference in the heart rates in the perioperative period between the two groups (P > 0.05). There was no statistically significant difference in the incidence of intraoperative physical response, respiratory depression, postoperative nausea and vomiting (PONV) and emergence agitation (EA) between the two groups (P > 0.05). The pain score at the postoperative hour 2 was lower in the LG group than in the G group (P < 0.05). CONCLUSION: Propofol-remifentanil intravenous anesthesia combined with long-acting local anesthetic regional block anesthesia, combined with laryngeal mask ventilation technology without muscle relaxants, can be safely used in pediatric eye surgery to achieve rapid and smooth recovery from general anesthesia and better postoperative analgesia. This anesthesia scheme can improve the comfort and safety of children in perioperative period, and has a certain clinical popularization value.


Asunto(s)
Propofol , Niño , Humanos , Anestesia General , Anestesia Intravenosa/métodos , Anestésicos Intravenosos , Propofol/uso terapéutico , Remifentanilo
15.
Nanoscale ; 16(14): 7123-7133, 2024 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-38501609

RESUMEN

Filters made of graphene oxide (GO) are promising for purification of water and selective sieving of specific ions; while some results indicate the ionic radius as the discriminating factor in the sieving efficiency, the exact mechanism of sieving is still under debate. Furthermore, most of the reported GO filters are planar coatings with a simple geometry and an area much smaller than commercial water filters. Here, we show selective transport of different ions across GO coatings deposited on standard hollow fiber filters with an area >10 times larger than typical filters reported. Thanks to the fabrication procedure, we obtained a uniform coating on such complex geometry with no cracks or holes. Monovalent ions like Na+ and K+ can be transported through these filters by applying a low electric voltage, while divalent ions are blocked. By combining transport and adsorption measurements with molecular dynamics simulations and spectroscopic characterization, we unravel the ion sieving mechanism and demonstrate that it is mainly due to the interactions of the ions with the carboxylate groups present on the GO surface at neutral pH.

16.
Opt Express ; 32(3): 3698-3709, 2024 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-38297585

RESUMEN

In this paper, we use the method of high order TMn1 mode selection from the concept of narrow-band Smith-Purcell radiation (SPR) for powerful, over-mode, multi-gap extended interaction circuit designs toward millimeter wave and Terahertz (THz) region. As a core part, the multiple gaps interaction structure, equivalent to a subwavelength hole array (SHA), excites the narrow band SPR when an electron beam is injected. The SPR energy is collected by a pair of closed cavities, which satisfies (n-1) standing wave units. The SPR energy in the optimized cavity allows a high index n TMn1 mode operation to achieve the strongest Ez field and high characteristic impedance in a closed multi-gap resonant circuit. This provides an effective design to establish a stable high-order TMn1 mode that supports extended interaction circuits with large cross sections. A 0.46 THz extended interaction circuit, employing the novel high order TM51-2π mode operation output structure, has been designed to demonstrate the efficient beam-wave interaction in the proposed system. The method of TMn1 mode selection provides new insight into the understanding of the high-frequency extended interaction circuits by introducing the SPR concept, benefiting the development of millimeter wave and THz vacuum electron devices (VEDs).

17.
Zool Res ; 45(1): 201-214, 2024 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-38199974

RESUMEN

Glycogen serves as the principal energy reserve for metabolic processes in aquatic shellfish and substantially contributes to the flavor and quality of oysters. The Jinjiang oyster ( Crassostrea ariakensis) is an economically and ecologically important species in China. In the present study, RNA sequencing (RNA-seq) and assay for transposase-accessible chromatin using sequencing (ATAC-seq) were performed to investigate gene expression and chromatin accessibility variations in oysters with different glycogen contents. Analysis identified 9 483 differentially expressed genes (DEGs) and 7 215 genes with significantly differential chromatin accessibility (DCAGs) were obtained, with an overlap of 2 600 genes between them. Notably, a significant proportion of these genes were enriched in pathways related to glycogen metabolism, including "Glycogen metabolic process" and "Starch and sucrose metabolism". In addition, genome-wide association study (GWAS) identified 526 single nucleotide polymorphism (SNP) loci associated with glycogen content. These loci corresponded to 241 genes, 63 of which were categorized as both DEGs and DCAGs. This study enriches basic research data and provides insights into the molecular mechanisms underlying the regulation of glycogen metabolism in C. ariakensis.


Asunto(s)
Crassostrea , Animales , Crassostrea/genética , Estudio de Asociación del Genoma Completo/veterinaria , Secuenciación de Inmunoprecipitación de Cromatina/veterinaria , RNA-Seq/veterinaria , Análisis de Secuencia de ARN/veterinaria , Cromatina , Glucógeno
18.
Nat Prod Res ; : 1-6, 2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38251834

RESUMEN

Two new protopanaxadiol type sapogenins, (3ß,12ß)-3,12,20-trihydroxydammar-24-en-26-al (1) and (3ß,12ß)-3,12,20-trihydroxydammar-24-en-26-oic acid (2), were isolated from the alkali hydrolysate of stems-leaves of Panax notoginseng, along with seven known analogues (3-9). Their structures were elucidated by spectroscopic analyses and single-crystal X-ray diffraction. Compound 2 and the known sapogenins 5-8 displayed weak to moderate inhibition of NO production in LPS-induced RAW264.7 macrophages with IC50 values from 44.5 to 143.6 µM, respectively.

19.
J Exp Bot ; 75(7): 1982-1996, 2024 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-38124377

RESUMEN

Drought-induced leaf senescence is associated with high sugar levels, which bears some resemblance to the syndrome of diabetes in humans; however, the underlying mechanisms of such 'plant diabetes' on carbon imbalance and the corresponding detoxification strategy are not well understood. Here, we investigated the regulatory mechanism of exogenous methylglyoxal (MG) on 'plant diabetes' in maize plants under drought stress applied via foliar spraying during the grain-filling stage. Exogenous MG delayed leaf senescence and promoted photoassimilation, thereby reducing the yield loss induced by drought by 14%. Transcriptome and metabolite analyses revealed that drought increased sugar accumulation in leaves through inhibition of sugar transporters that facilitate phloem loading. This led to disequilibrium of glycolysis and overaccumulation of endogenous MG. Application of exogenous MG up-regulated glycolytic flux and the glyoxalase system that catabolyses endogenous MG and glycation end-products, ultimately alleviating 'plant diabetes'. In addition, the expression of genes facilitating anabolism and catabolism of trehalose-6-phosphate was promoted and suppressed by drought, respectively, and exogenous MG reversed this effect, implying that trehalose-6-phosphate signaling in the mediation of 'plant diabetes'. Furthermore, exogenous MG activated the phenylpropanoid biosynthetic pathway, promoting the production of lignin and phenolic compounds, which are associated with drought tolerance. Overall, our findings indicate that exogenous MG activates defense-related pathways to alleviate the toxicity derived from 'plant diabetes', thereby helping to maintain leaf function and yield production under drought.


Asunto(s)
Diabetes Mellitus , Zea mays , Humanos , Zea mays/genética , Senescencia de la Planta , Piruvaldehído/metabolismo , Piruvaldehído/farmacología , Sequías , Diabetes Mellitus/metabolismo , Azúcares/metabolismo , Hojas de la Planta/metabolismo , Estrés Fisiológico
20.
Life Sci Alliance ; 7(1)2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-37931956

RESUMEN

Mitochondria interact with the ER at structurally and functionally specialized membrane contact sites known as mitochondria-ER contact sites (MERCs). Combining proximity labelling (BioID), co-immunoprecipitation, confocal microscopy and subcellular fractionation, we found that the ER resident SMP-domain protein ESYT1 was enriched at MERCs, where it forms a complex with the outer mitochondrial membrane protein SYNJ2BP. BioID analyses using ER-targeted, outer mitochondrial membrane-targeted, and MERC-targeted baits, confirmed the presence of this complex at MERCs and the specificity of the interaction. Deletion of ESYT1 or SYNJ2BP reduced the number and length of MERCs. Loss of the ESYT1-SYNJ2BP complex impaired ER to mitochondria calcium flux and provoked a significant alteration of the mitochondrial lipidome, most prominently a reduction of cardiolipins and phosphatidylethanolamines. Both phenotypes were rescued by reexpression of WT ESYT1 and an artificial mitochondria-ER tether. Together, these results reveal a novel function for ESYT1 in mitochondrial and cellular homeostasis through its role in the regulation of MERCs.


Asunto(s)
Calcio , Retículo Endoplásmico , Mitocondrias , Sinaptotagminas , Calcio/metabolismo , Retículo Endoplásmico/metabolismo , Homeostasis , Lípidos , Mitocondrias/metabolismo , Sinaptotagminas/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA