Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 109
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
N Engl J Med ; 390(3): 230-241, 2024 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-38231624

RESUMEN

BACKGROUND: Simnotrelvir is an oral 3-chymotrypsin-like protease inhibitor that has been found to have in vitro activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and potential efficacy in a phase 1B trial. METHODS: In this phase 2-3, double-blind, randomized, placebo-controlled trial, we assigned patients who had mild-to-moderate coronavirus disease 2019 (Covid-19) and onset of symptoms within the past 3 days in a 1:1 ratio to receive 750 mg of simnotrelvir plus 100 mg of ritonavir or placebo twice daily for 5 days. The primary efficacy end point was the time to sustained resolution of symptoms, defined as the absence of 11 Covid-19-related symptoms for 2 consecutive days. Safety and changes in viral load were also assessed. RESULTS: A total of 1208 patients were enrolled at 35 sites in China; 603 were assigned to receive simnotrelvir and 605 to receive placebo. Among patients in the modified intention-to-treat population who received the first dose of trial drug or placebo within 72 hours after symptom onset, the time to sustained resolution of Covid-19 symptoms was significantly shorter in the simnotrelvir group than in the placebo group (180.1 hours [95% confidence interval {CI}, 162.1 to 201.6] vs. 216.0 hours [95% CI, 203.4 to 228.1]; median difference, -35.8 hours [95% CI, -60.1 to -12.4]; P = 0.006 by Peto-Prentice test). On day 5, the decrease in viral load from baseline was greater in the simnotrelvir group than in the placebo group (mean difference [±SE], -1.51±0.14 log10 copies per milliliter; 95% CI, -1.79 to -1.24). The incidence of adverse events during treatment was higher in the simnotrelvir group than in the placebo group (29.0% vs. 21.6%). Most adverse events were mild or moderate. CONCLUSIONS: Early administration of simnotrelvir plus ritonavir shortened the time to the resolution of symptoms among adult patients with Covid-19, without evident safety concerns. (Funded by Jiangsu Simcere Pharmaceutical; ClinicalTrials.gov number, NCT05506176.).


Asunto(s)
COVID-19 , Inhibidores de Proteasa de Coronavirus , Adulto , Humanos , Administración Oral , Antivirales/administración & dosificación , Antivirales/efectos adversos , Antivirales/farmacología , Antivirales/uso terapéutico , China , Proteínas M de Coronavirus/antagonistas & inhibidores , Proteínas M de Coronavirus/metabolismo , Inhibidores de Proteasa de Coronavirus/administración & dosificación , Inhibidores de Proteasa de Coronavirus/efectos adversos , Inhibidores de Proteasa de Coronavirus/farmacología , Inhibidores de Proteasa de Coronavirus/uso terapéutico , COVID-19/metabolismo , COVID-19/terapia , Tratamiento Farmacológico de COVID-19/métodos , Método Doble Ciego , Ritonavir/administración & dosificación , Ritonavir/efectos adversos , Ritonavir/farmacología , Ritonavir/uso terapéutico , SARS-CoV-2/efectos de los fármacos , Factores de Tiempo , Combinación de Medicamentos
2.
Opt Express ; 32(4): 5273-5286, 2024 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-38439259

RESUMEN

We investigate theoretically the photoelectron momentum distributions (PMDs) of the helium atom in the few-cycle nonlinear chirped laser pulse. The numerical results show that the direction of the spider-like interference structure in PMDs exhibits periodic variations with the increase of the chirp parameter. It is illustrated that the direction of the spider-like interference structure is related to the direction of the electron motion by tracking the trajectories of the electrons. We also demonstrate that the carrier-envelope phase can precisely control the opening of the ionization channel. In addition, we investigate the PMDs when a chirp-free second harmonic (SH) laser pulse is added to the chirped laser field, the numerical results show that the interference patterns can change from only spider-like interference structure to both spider-like and ring-like interference structures.

3.
Opt Lett ; 49(6): 1425-1428, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38489416

RESUMEN

Terahertz cross correlation spectroscopy (THz-CCS) systems using broadband incoherent light as the pumping source have received increasing attention from researchers in recent years. However, a comprehensive and in-depth understanding of THz-CCS is still needed to obtain a detailed optimization scheme. Here we systematically investigate the influences of the detection parameters, light propagation process, and pump source on the CCS signals. The impacts of the filter slopes and time constants in lock-in detection are revealed for optimizing the signal-to-noise ratio and bandwidth of the THz signal. By varying the optical fiber length and dispersion coefficient, the dispersion insensitivity of THz-CCS was experimentally demonstrated. The comparison of different pump sources (SLD and ASE) shows that the over-wide and non-flat pump spectrum may attenuate the CCS signal because of the energy waste brought by the photomixing process under the limited bandwidth of the photomixer. Our research may lead to a deeper understanding and further optimization of the THz-CCS system, which will promote the development and widespread application of what is to the best of our knowledge a new technique.

4.
Dig Dis Sci ; 69(3): 978-988, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38341392

RESUMEN

AIM: This study aimed to assess the effectiveness and safety of tenofovir alafenamide fumarate (TAF) in the prevention of mother-to-child transmission (MTCT) of hepatitis B virus (HBV). METHODS: We performed a meta-analysis of studies from the Cochrane Library, PubMed, ClinicalTrials.gov, Web of Science, EMBASE, China National Knowledge Infrastructure (CNKI), China Medical Information Network, and Wanfang databases. The databases were searched from inception to January 7, 2023, for cohort studies and randomized controlled trials (RCTs) comparing the use of TAF antivirals to other antivirals during pregnancy. We combined the data by means of a random-effect DerSimonian-Laird model and risk ratios (RRs) or a random-effect inverse variance model and standardized mean differences (SMDs) to determine the influence on mothers and infants. Our primary outcomes were infant weight, height, head size, birth defects, and Apgar scores. Additionally, we assessed whether newborns tested positive for hepatitis B surface antigen (HBsAg) at birth and at six months of age. The secondary outcomes of our investigation were alterations in levels of HBV deoxyribonucleic acid (DNA), alanine aminotransferase (ALT), total bilirubin (TBIL), blood creatinine, and urine ß2-microglobulin (ß2-M) in mothers. RESULTS: An extensive literature search identified 216 relevant publications; three cohort studies and two RCTs were included in this study. A total of 341 mothers were treated with TAF, and 342 were treated with other antiviral agents. TAF was as effective as other antiviral medications at lowering HBV MTCT rates at birth and at 6 months of age and ALT, TBIL, and HBV DNA levels. Moreover, compared with other antiviral drugs, TAF did not affect infant weight, height, head size, Apgar scores, and birth defects or maternal blood creatinine or ß2-M levels. CONCLUSIONS: TAF antiviral therapy during pregnancy was found to be safe for both mothers and fetuses.


Asunto(s)
Hepatitis B Crónica , Hepatitis B , Femenino , Humanos , Lactante , Recién Nacido , Embarazo , Adenina/efectos adversos , Antivirales/efectos adversos , Creatinina , ADN Viral , Fumaratos/efectos adversos , Hepatitis B/tratamiento farmacológico , Hepatitis B/prevención & control , Virus de la Hepatitis B/genética , Hepatitis B Crónica/tratamiento farmacológico , Transmisión Vertical de Enfermedad Infecciosa/prevención & control
5.
Molecules ; 29(12)2024 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-38930800

RESUMEN

Cangjie Temple was built to commemorate Cangjie, the legendary inventor of Chinese characters. It stands as one of the few remaining temples in China dedicated to the invention and creation of writing. In this study, the material properties of wooden paintings from the Cangjie temple were characterized using Polarized Light Microscopy (PLM), Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM-EDS), Micro-confocal Raman Spectroscopy, X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC/MS). It was confirmed that the pigments of the paintings included cinnabar, lapis lazuli, lead white, Paris green, and carbon black. The proteinaceous glue was used as an adhesive in the pigment samples, with tung oil likely being utilized as a primer for the wooden structures before painting. This study not only provides valuable data support for the conservation and restoration of the architectural features of Cangjie Temple but also provides useful reference for the maintenance and inheritance of similar ancient buildings.

6.
Molecules ; 29(6)2024 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-38543001

RESUMEN

The durability of wooden heritage objects and sites can be affected by external environmental factors, leading to decay, cracking, and other forms of deterioration, which might ultimately result in significant and irreversible loss. In this study, a FEVE resin was modified with Ag2O/OH-MWCNTS (MA), denoted as MAF, where three concentrations were prepared using in situ precipitation, and the resulting composite adhesive was characterized by a high viscosity and effective bacteriostatic properties, demonstrating a better viscosity and thermal stability, as well as antibacterial properties, than pure FEVE resin. The results show that MAF adhesives present good thermal stability, as evidenced by a lower mass loss rate following treatment at 800 °C compared to the pure FEVE resin. At a consistent shear rate, the viscosity of MAF demonstrates a notable increase with the proportion of MA, which is better than that of FEVE. This suggests that the nano-Ag2O particles in MA act as physical crosslinking agents in FEVE, improving the viscosity of the composite adhesive MAF. The adhesion strength between MAF and wood exhibits a similar trend, with wooden samples showing higher shear strengths as the proportion of MA increases in comparison to FEVE. Simultaneously, the antibacterial effects of the MAF adhesive exceeded 1 mm for Trichoderma, Aspergillus niger, and white rot fungi. The antibacterial activity of the MAF adhesive exhibited a direct correlation with the concentration of Ag2O/OH-MWCNTS, with the most pronounced inhibitory effect observed on Trichoderma. The MAF adhesive demonstrates promising prospects as an adhesive for wooden heritage artifacts, offering a novel approach for the rapid, environmentally friendly, and efficient development of composite adhesives with superior adhesive properties.

7.
Ann Hematol ; 102(4): 937-946, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36763109

RESUMEN

Acute myeloid leukemia (AML) patients can benefit from allogeneic hematopoietic cell transplantation (alloHCT) and achieve long-term remission. Recovery of T cell quantity and quality is critical to reduce the incidences of life-threatening complications after alloHCT. Although the general recovery level of γδ T cells is recognized to be associated with outcomes of patients who suffered from various hematological diseases and received alloHCT, the correlation between γδ T cell subsets and the prognosis in AML patients following transplantation remains to be investigated. In the current study, the recoveries of T cell subpopulations in 103 AML patients were dissected at different time points after haploidentical HCT (haploHCT). Statistical analyses showed that the absolute number of Vδ2+ T cells on day 90 was an independent risk factor for predicting 2-year OS in AML patients following haploHCT. The survival advantage from the improved recovery of day-90 Vδ2+ T cells was attributed to reducing the infection-related mortality. Consistently, lower 2-year non-relapse mortality was found in recipients with higher day-90 levels of Vδ2+ T cells. Notably, day-270 Vδ2+ T cell numbers reversely correlated to both 2-year and 5-year probabilities of relapse in this scenario. These results highlighted the significant correlation of Vδ2+ T cells recovery with long-term survival and relapse after alloHCT, suggesting that Vδ2+ T cells-based immune strategies may help control infectious complications and leukemia recurrence in AML patients.


Asunto(s)
Trasplante de Células Madre Hematopoyéticas , Leucemia Mieloide Aguda , Humanos , Trasplante Homólogo , Incidencia , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Recurrencia , Enfermedad Crónica
8.
Biochem Biophys Res Commun ; 597: 52-57, 2022 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-35123266

RESUMEN

Colorectal cancer (CRC) is one of the most common malignancies of the gastrointestinal tract, and its prognosis is closely related to the degree of tumor invasion and metastasis. Ribosome production factor 2 homolog (RPF2) plays an important role in the process of ribosome biogenesis; however, its biological function in the progression of malignant tumors including CRC remains unknown. It was found that RPF2 expression was significantly higher in CRC tissues than in the adjacent normal tissue, using mRNA chip technology. This study aimed to explore the role of RPF2 in the invasion and migration of CRC cells and investigate its probable molecular mechanism. The results demonstrated that RPF2 is not only highly expressed in CRC tissues and cell lines but can also activate the AKT/GSK-3ß signaling pathway through direct interaction with CARM1, promoting epithelial-mesenchymal transition, and consequently enhancing the migration and invasion abilities of CRC cells in vitro and in vivo. Thus, we speculated that RPF2 may become a novel therapeutic target for suppression of local invasion and distant metastasis of CRC.

9.
J Sep Sci ; 45(15): 2914-2923, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35689602

RESUMEN

Dihydromethysticin, a natural component from Piper methysticum Forst, has been reported to display pharmacological effects in mental disorders and some malignant tumors. However, the metabolism of this component remained unknown. The goal of this work was conducted to discover the metabolic profiles of dihydromethysticin. The in vitro incubation was performed by incubating dihydromethysticin with rat, monkey, and human liver microsomes and hepatocytes. An analytical assay of ultra-high performance liquid chromatography combined with Orbitrap high-resolution mass spectrometry was utilized to detect and identify the metabolites. With high resolution mass spectrometric determination, the accurate mass, elemental composition, and product ions of the metabolites were determined, which enabled structural characterization to become easy. Under the present conditions, four phase-I metabolites, as well as six phase-II metabolites, were detected and their tentative structures were characterized by mass spectra. M4 was found as the most abundant metabolite both in liver microsomes and hepatocytes. Cytochrome P450 1A2, 2C9, and 3A4 contributed to the formation of this metabolite by using human recombinant P450 enzymes. M4 can be oxidized into reactive ortho-quinone intermediate followed by conjugating with glutathione. M4 was also subject to glucuronidation (M1 and M2) and methylation (M5). Demethylenation, oxidation, hydroxylation, glucuronidation, glutathionylation, and methylation were the primary metabolic pathways of dihydromethysticin. This study provides in vitro metabolism data of dihydromethysticin, which is indispensable for understanding the disposition of this compound.


Asunto(s)
Pironas , Espectrometría de Masas en Tándem , Animales , Cromatografía Líquida de Alta Presión/métodos , Humanos , Microsomas Hepáticos/metabolismo , Ratas , Espectrometría de Masas en Tándem/métodos
10.
J Asian Nat Prod Res ; 24(6): 550-555, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34308728

RESUMEN

Two new sesquiterpenes, litseachrandaevanes C and D (1 and 2), together with five known sesquiterpenes (3 - 7), were isolated from the stems of Fissistigma glaucescens (Hance) Merr. Their structures were elucidated using comprehensive spectroscopic methods. The inhibitory effect of all compounds on the proliferation of primary synovial cells was evaluated. Compound 3 showed inhibitory effect on the proliferation of synoviocytes, with an IC50 value of 12.5 µM.


Asunto(s)
Annonaceae , Sesquiterpenos , Sinoviocitos , Annonaceae/química , Proliferación Celular , Estructura Molecular , Sesquiterpenos/química , Sesquiterpenos/farmacología
11.
Breast Cancer Res Treat ; 187(1): 69-80, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33630196

RESUMEN

PURPOSE: Current studies on circulating cell-free DNA (cfDNA) have been focusing on its potential as biomarkers in liquid biopsy by detecting its content or genetic and epigenetic changes for the evaluation of tumor burden and therapeutic efficacy. However, the regulatory mechanism of cfDNA release remains unclear. Stat3 has been documented as an oncogene for the development and metastasis of breast cancer cells. In this study, we investigated whether Stat3 affects the release of cfDNA into blood and its association with the number of circulating tumor cells (CTCs). METHODS: The cfDNA level in plasma of patients with breast cancer and healthy volunteers were determined by quantitative real-time PCR. Three mouse breast cancer models with different Stat3 expression were generated and used to established three breast cancer orthotopic animal models to examine the effect of Stat3 on cfDNA release in vivo. Stat3 mediated Epithelial-mesenchymal phenotype transition of CTCs was determined by immunofluorescence assay and Western blot assay. RESULTS: The data showed that Stat3 increased circulating cfDNA, which is correlated with the increased volume of primary tumors and number of CTCs, accompanied with the dynamic EMT changes regulated by Snail induction. Furthermore, the high level of total circulating cfDNA and Stat3-cfDNA in patients with breast cancer were detected by quantitative real-time PCR using GAPDH and Stat3 primers. CONCLUSION: Our results suggested that Stat3 increases the circulating cfDNA and CTCs in breast cancer.


Asunto(s)
Neoplasias de la Mama , Ácidos Nucleicos Libres de Células , Células Neoplásicas Circulantes , Animales , Biomarcadores de Tumor/genética , Neoplasias de la Mama/genética , Ácidos Nucleicos Libres de Células/genética , Transición Epitelial-Mesenquimal/genética , Femenino , Humanos , Biopsia Líquida , Ratones , Factor de Transcripción STAT3/genética
12.
Physiol Plant ; 172(4): 1867-1879, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33724475

RESUMEN

The responses of the GsCLC-c2 gene and its promoter to NaCl stress, as well as the Cl- /salt tolerance of GsCLC-c2-transgenic Arabidopsis and overexpressed or RNAi wild soybean hairy root composite plants, were investigated. Results showed that both GsCLC-c2 and its promoter display enhanced induction under salt stress. In the transgenic Arabidopsis WT-GsCLC-c2 and atclc-c-GsCLC-c2 seedlings, the salt-induced growth reduction was markedly ameliorated; plant fresh weight, leaf area, and relative water content (RWC) increased; relative electrolytic leakage (REL), and malondialdehyde (MDA) content in shoots decreased significantly. In addition, accumulation of Cl- and K+ , especially Cl- , increased markedly in roots to minimize Cl- transport to shoots and maintain higher and lower Cl- /NO3 - ratios in roots and shoots, respectively. When compared to GsCLC-c2-RNAi wild soybean composite plants under salt stress, clear advantages, such as growth appearance, plant height, and leaf area, were displayed by GsCLC-c2-overexpressing composite plants. Moreover, their REL values in roots and leaves declined significantly. The accumulation of absorbed Cl- and Na+ in the roots increased, as the transportation to the stems and leaves decreased, the NO3 - content in roots, stems, and leaves significantly increased, and the changes in K+ contents were small, which resulted in the maintenance of a low Cl- /NO3 - ratio in all plant parts and low Na+ /K+ ratio in stems and leaves. Taken together, these results highlight the role of GsCLC-c2 in regulating anionic homeostasis in NaCl-stressed transgenic Arabidopsis and soybean composite plants to maintain lower Cl- /NO3 - ratios in shoots, thus conferring enhanced Cl- /salt tolerance.


Asunto(s)
Arabidopsis , Tolerancia a la Sal , Arabidopsis/genética , Arabidopsis/metabolismo , Cloruros , Regulación de la Expresión Génica de las Plantas , Homeostasis , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Tolerancia a la Sal/genética , Glycine max/genética , Glycine max/metabolismo
13.
J Neurovirol ; 26(3): 456-458, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32424616
14.
Mol Biol Rep ; 47(12): 9361-9371, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33244663

RESUMEN

Chloride channels (CLCs) are kinds of anion transport protein family members that are mainly distributed in cell endomembrane systems of prokaryotic and eukaryotic organisms and mediate anion (Cl-, as a representative) transport and homeostasis. Some CLC genes have been reported to be involved in Cl-/salt tolerance of plants exposed to NaCl stress. Through BLAST in cotton database, a total of 22 CLCs were identified in genomes A and D in upland cotton (Gossypium hirsutum L.), and except for GhCLC6 and GhCLC17, they formed highly similar homologous genes pairs. According to the prediction in PlantCARE database, many cis-acting elements related to abiotic stress responses, including ABREs, AREs, GT-1s, G-boxes, MYBs, MYCs, etc., were found in the promoters of GhCLCs. qRT-PCR revealed that most GhCLC gene expression was upregulated in the roots and leaves of cotton seedlings under salt stress, and those of homologous GhCLC4/15, GhCLC5/16, and GhCLC7/18 displayed more obvious expression. Furthermore, according to leaf virus-induced gene silencing (VIGS) assay and compared with the salt-stressed GhCLC4/15- and GhCLC7/18-silenced cotton plants, the salt-stressed GhCLC5/16-silenced plants displayed relatively better growth with significant increases in both Cl- content and Cl-/NO3- ratio in the roots and drop of the same parameters in the leaves. These results indicate that homologous GhCLC5/16, with the highest NaCl-induced upregulation of expression and the maximum number of MYC cis-acting elements, might be the key members contributing to cotton Cl-/salt tolerance by regulating the transport, interaction and homeostasis of Cl- and NO3-.


Asunto(s)
Canales de Cloruro/genética , Genes de Plantas , Gossypium/genética , Gossypium/metabolismo , Proteínas de Plantas/genética , Estrés Salino/genética , Transcriptoma , Bases de Datos Genéticas , Regulación de la Expresión Génica de las Plantas , Homeostasis/genética , Filogenia , Hojas de la Planta/genética , Raíces de Plantas/genética , Regiones Promotoras Genéticas , Tolerancia a la Sal/genética , Plantones/genética , Regulación hacia Arriba/genética
15.
Phytochem Anal ; 31(3): 340-348, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-31899590

RESUMEN

Hydrophilic iridoid glycosides and oligosaccharides are the major active ingredients of Radix Rehmanniae. Analysis of oligosaccharides is a challenging task because they are highly hydrophilic, with similar chemical structures and absence of chromophore and fluorophore groups. The difficulty for simultaneous analysis of iridoid glycosides and oligosaccharides in Radix Rehmanniae is increased due to the polarity difference between the two types of ingredients. OBJECTIVE: To develop a method for simultaneous determination of iridoid glycosides (ajugol, catalpol) and oligosaccharides (sucrose, melibiose, raffinose, mannotriose and stachyose) in Radix Rehmanniae. METHODOLOGY: Microwave-assisted extraction (MAE) was established to extract target analytes from Radix Rehmanniae samples using methanol-water (60:40, v/v) as the extraction solvent. Fast separation of seven analytes was achieved by hydrophilic interaction liquid chromatography (HILIC) using an Accucore-150-Amide-HILIC column. Sensitive and selective detection of the analytes was performed by triple quadrupole tandem mass spectrometry (TQ-MS/MS) using multiple reaction monitoring in positive electrospray ionisation mode. RESULTS: Good linearities were achieved for all the analytes with the correlation coefficients above 0.9991. The precisions resulted in deviations of less than 5.0% and the recoveries ranged from 93.8% to 105.5%. The established method was successfully applied to the analysis of iridoid glycosides and oligosaccharides in 12 samples of crude and processed Radix Rehmanniae. CONCLUSION: A simple, rapid and sensitive method based on MAE combined with HILIC-UHPLC-TQ-MS/MS was developed for simultaneous determination of iridoid glycosides and oligosaccharides in Radix Rehmanniae for the first time. The method exhibited excellent performance with simple sample preparation, short analysis time, high selectivity and sensitivity.


Asunto(s)
Rehmannia , Cromatografía Líquida de Alta Presión , Cromatografía Liquida , Interacciones Hidrofóbicas e Hidrofílicas , Glicósidos Iridoides , Microondas , Oligosacáridos , Reproducibilidad de los Resultados , Espectrometría de Masas en Tándem
16.
J Cell Biochem ; 120(8): 13501-13508, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-30938883

RESUMEN

Nitrogen is the key factor for plant survival and growth, especially in the desert. Stipagrostis pennata, a sand born drought-resistant plant, could colonize pioneerly in Gurbantunggut Desert during revegetation. One strategy for their environment adaptation was the rhizosheath formatted by root-hair, mucilaginous exudates, microbial components, and soil particles, for which not only provides a favorable living microenvironment but also supplies essential nutrients. To understand the relationship between microorganisms living in rhizosheaths and the nitrogen nutrition supply, the microbial diversity and nitrogenase activity was estimated during the growth of S. pennata. Five samples of the rhizosheath, which based on the development periods of the plant, regreen, flowering, filling, seed maturating, and withering period, were collected. The nitrogenase activity was estimated by acetylene reduction and the microbial diversity was analyzed by 16S rRNA high-throughput sequencing. The results showed that the nitrogenase activity was increased slowly during regreen to flowering, while reached a peak rapidly at filling sample and then decreased gradually. A total of 274 operational taxonomic units (OTUs) were identified and significant differences in community structure and composition at each growth period. Among them, the main phyla included Actinobacteria and Proteus, which were the most abundant phyla in all periods. In addition, the microbial diversity in the grain filling period was higher than other periods in view of the analysis of alpha diversity and beta diversity. Furthermore, principal component analysis (PCA) analysis showed that the microbial communities in the filling period was low in similarity with other periods. Most importantly, the OTUs associated with nitrogen fixation is the most during the filling period, involving Phagecidae and Fucoraceae. Overall, the study not only revealed the differences in nitrogenase activity among different developmental periods in S. pennata, but also explored the potential bridges between it and community structure and diversity of bacteria.


Asunto(s)
Fijación del Nitrógeno/genética , Nitrogenasa/genética , Poaceae/genética , Rizosfera , Actinobacteria/genética , Actinobacteria/crecimiento & desarrollo , Ecosistema , Regulación de la Expresión Génica de las Plantas/genética , Variación Genética , Secuenciación de Nucleótidos de Alto Rendimiento , Poaceae/crecimiento & desarrollo , Poaceae/microbiología , Proteus/genética , Proteus/crecimiento & desarrollo , ARN Ribosómico 16S/genética , Suelo
17.
Emerg Infect Dis ; 25(5): 1028-1029, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-31002064

RESUMEN

In China in 2013, a man acquired rabies after sucking wounds of his son, who had been bitten by a stray dog. The man declined postexposure prophylaxis (hyperimmunoglobulin and vaccine) and died; the son accepted prophylaxis and survived. Physicians should be aware of rabies transmission through mucosal exposure and encourage postexposure prophylaxis.


Asunto(s)
Mucosa Bucal/virología , Virus de la Rabia , Rabia/epidemiología , Rabia/transmisión , Adolescente , Adulto , Animales , Mordeduras y Picaduras , Notificación de Enfermedades , Perros , Resultado Fatal , Historia del Siglo XXI , Humanos , Masculino , Profilaxis Posexposición , Rabia/historia
18.
BMC Plant Biol ; 19(1): 121, 2019 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-30935372

RESUMEN

BACKGROUND: The anionic toxicity of plants under salt stress is mainly caused by chloride (Cl-). Thus Cl- influx, transport and their regulatory mechanisms should be one of the most important aspects of plant salt tolerance studies, but are often sidelined by the focus on sodium (Na+) toxicity and its associated adaptations. Plant chloride channels (CLCs) are transport proteins for anions including Cl- and nitrate (NO3-), and are critical for nutrition uptake and transport, adjustment of cellular turgor, stomatal movement, signal transduction, and Cl- and NO3- homeostasis under salt stress. RESULTS: Among the eight soybean CLC genes, the tonoplast-localized c2 has uniquely different transcriptional patterns between cultivated soybean N23674 and wild soybean BB52. Using soybean hairy root transformation, we found that GsCLC-c2 over-expression contributed to Cl- and NO3- homeostasis, and therefore conferred salt tolerance, through increasing the accumulation of Cl- in the roots, thereby reducing their transportation to the shoots where most of the cellular damages occur. Also, by keeping relatively high levels of NO3- in the aerial part of the plant, GsCLC-c2 could reduce the Cl-/NO3- ratio. Wild type GsCLC-c2, but not its mutants (S184P, E227V and E294G) with mutations in the conserved domains, is able to complement Saccharomyces cerevisiae △gef1 Cl- sensitive phenotype. Using two-electrode voltage clamp on Xenopus laevis oocytes injected with GsCLC-c2 cRNA, we found that GsCLC-c2 transports both Cl- and NO3- with slightly different affinity, and the affinity toward Cl- was pH-independent. CONCLUSION: This study revealed that the expression of GsCLC-c2 is induced by NaCl-stress in the root of wild soybean. The tonoplast localized GsCLC-c2 transports Cl- with a higher affinity than NO3- in a pH-independent fashion. GsCLC-c2 probably alleviates salt stress in planta through the sequestration of excess Cl- into the vacuoles of root cells and thus preventing Cl- from entering the shoots where it could result in cellular damages.


Asunto(s)
Canales de Cloruro/metabolismo , Cloruros/metabolismo , Glycine max/genética , Transporte Biológico , Canales de Cloruro/genética , Nitratos/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Salinidad , Tolerancia a la Sal , Glycine max/fisiología
19.
Int J Mol Sci ; 20(12)2019 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-31208046

RESUMEN

The salt overly sensitive 1 (SOS1) gene encodes the plasma membrane Na+/H+ antiporter, SOS1, that is mainly responsible for extruding Na+ from the cytoplasm and reducing the Na+ content in plants under salt stress and is considered a vital determinant in conferring salt tolerance to the plant. However, studies on the salt tolerance function of the TrSOS1 gene of recretohalophytes, such as Tamarix, are limited. In this work, the effects of salt stress on cotton seedlings transformed with tobacco-rattle-virus-based virus-induced gene silencing (VIGS) of the endogenous GhSOS1 gene, or Agrobacterium rhizogenes strain K599-mediated TrSOS1-transgenic hairy root composite cotton plants exhibiting VIGS of GhSOS1 were first investigated. Then, with Arabidopsis thaliana AtSOS1 as a reference, differences in the complementation effect of TrSOS1 or GhSOS1 in a yeast mutant were compared under salt treatment. Results showed that compared to empty-vector-transformed plants, GhSOS1-VIGS-transformed cotton plants were more sensitive to salt stress and had reduced growth, insufficient root vigor, and increased Na+ content and Na+/K+ ratio in roots, stems, and leaves. Overexpression of TrSOS1 enhanced the salt tolerance of hairy root composite cotton seedlings exhibiting GhSOS1-VIGS by maintaining higher root vigor and leaf relative water content (RWC), and lower Na+ content and Na+/K+ ratio in roots, stems, and leaves. Transformations of TrSOS1, GhSOS1, or AtSOS1 into yeast NHA1 (Na+/H+ antiporter 1) mutant reduced cellular Na+ content and Na+/K+ ratio, increased K+ level under salt stress, and had good growth complementation in saline conditions. In particular, the ability of TrSOS1 or GhSOS1 to complement the yeast mutant was better than that of AtSOS1. This may indicate that TrSOS1 is an effective substitute and confers enhanced salt tolerance to transgenic hairy root composite cotton seedlings, and even the SOS1 gene from salt-tolerant Tamarix or cotton may have higher efficiency than salt-sensitive Arabidopsis in regulating Na+ efflux, maintaining Na+ and K+ homeostasis, and therefore contributing to stronger salt tolerance.


Asunto(s)
Silenciador del Gen , Gossypium/genética , Brotes de la Planta/genética , Tolerancia a la Sal/genética , Plantones/genética , Intercambiadores de Sodio-Hidrógeno/genética , Tamaricaceae/genética , Regulación de la Expresión Génica de las Plantas , Prueba de Complementación Genética , Mutación , Fenotipo , Plantas Modificadas Genéticamente , Plantones/virología , Intercambiadores de Sodio-Hidrógeno/metabolismo , Estrés Fisiológico/genética
20.
Arch Virol ; 163(3): 731-735, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29214362

RESUMEN

Jasmine virus H (JaVH) is a novel virus associated with symptoms of yellow mosaic on jasmine. The JaVH genome is 3,867 nt in length with five open reading frames (ORFs) encoding a 27-kDa protein (ORF 1), an 87-kDa replicase protein (ORF 2), two centrally located movement proteins (ORF 3 and 4), and a 37-kDa capsid protein (ORF 5). Based on genomic and phylogenetic analysis, JaVH is predicted to be a member of the genus Pelarspovirus in the family Tombusviridae.


Asunto(s)
Genoma Viral , Jasminum/virología , Filogenia , ARN Viral/genética , Tombusviridae/genética , Secuencia de Bases , Proteínas de la Cápside/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Sistemas de Lectura Abierta , ARN Polimerasa Dependiente del ARN/genética , Tombusviridae/clasificación , Tombusviridae/aislamiento & purificación
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA