Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 936
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Proc Natl Acad Sci U S A ; 121(8): e2316716121, 2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38349874

RESUMEN

Understanding the molecular-level mechanisms involved in transmembrane ion selectivity is essential for optimizing membrane separation performance. In this study, we reveal our observations regarding the transmembrane behavior of Li+ and Mg2+ ions as a response to the changing pore solvation abilities of the covalent-organic-framework (COF) membranes. These abilities were manipulated by adjusting the lengths of the oligoether segments attached to the pore channels. Through comparative experiments, we were able to unravel the relationships between pore solvation ability and various ion transport properties, such as partitioning, conduction, and selectivity. We also emphasize the significance of the competition between Li+ and Mg2+ with the solvating segments in modulating selectivity. We found that increasing the length of the oligoether chain facilitated ion transport; however, it was the COF membrane with oligoether chains containing two ethylene oxide units that exhibited the most pronounced discrepancy in transmembrane energy barrier between Li+ and Mg2+, resulting in the highest separation factor among all the evaluated membranes. Remarkably, under electro-driven binary-salt conditions, this specific COF membrane achieved an exceptional Li+/Mg2+ selectivity of up to 1352, making it one of the most effective membranes available for Li+/Mg2+ separation. The insights gained from this study significantly contribute to advancing our understanding of selective ion transport within confined nanospaces and provide valuable design principles for developing highly selective COF membranes.

2.
J Biol Chem ; 300(3): 105741, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38340793

RESUMEN

Type VI secretion systems (T6SS) are bacterial macromolecular complexes that secrete effectors into target cells or the extracellular environment, leading to the demise of adjacent cells and providing a survival advantage. Although studies have shown that the T6SS in Pseudomonas aeruginosa is regulated by the Quorum Sensing system and second messenger c-di-GMP, the underlying molecular mechanism remains largely unknown. In this study, we discovered that the c-di-GMP-binding adaptor protein PA0012 has a repressive effect on the expression of the T6SS HSI-I genes in P. aeruginosa PAO1. To probe the mechanism by which PA0012 (renamed TssZ, Type Six Secretion System -associated PilZ protein) regulates the expression of HSI-I genes, we conducted yeast two-hybrid screening and identified HinK, a LasR-type transcriptional regulator, as the binding partner of TssZ. The protein-protein interaction between HinK and TssZ was confirmed through co-immunoprecipitation assays. Further analysis suggested that the HinK-TssZ interaction was weakened at high c-di-GMP concentrations, contrary to the current paradigm wherein c-di-GMP enhances the interaction between PilZ proteins and their partners. Electrophoretic mobility shift assays revealed that the non-c-di-GMP-binding mutant TssZR5A/R9A interacts directly with HinK and prevents it from binding to the promoter of the quorum-sensing regulator pqsR. The functional connection between TssZ and HinK is further supported by observations that TssZ and HinK impact the swarming motility, pyocyanin production, and T6SS-mediated bacterial killing activity of P. aeruginosa in a PqsR-dependent manner. Together, these results unveil a novel regulatory mechanism wherein TssZ functions as an inhibitor that interacts with HinK to control gene expression.


Asunto(s)
Proteínas Bacterianas , Regulación Bacteriana de la Expresión Génica , Pseudomonas aeruginosa , Transcripción Genética , Sistemas de Secreción Tipo VI , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , GMP Cíclico/análogos & derivados , GMP Cíclico/metabolismo , Ensayo de Cambio de Movilidad Electroforética , Inmunoprecipitación , Mutación , Regiones Promotoras Genéticas , Unión Proteica , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo , Piocianina/metabolismo , Percepción de Quorum , Sistemas de Mensajero Secundario , Técnicas del Sistema de Dos Híbridos , Sistemas de Secreción Tipo VI/genética , Sistemas de Secreción Tipo VI/metabolismo
3.
Proc Natl Acad Sci U S A ; 119(11): e2113074119, 2022 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-35254894

RESUMEN

SignificanceWith obesity on the rise, there is a growing appreciation for intracellular lipid droplet (LD) regulation. Here, we show how saturated fatty acids (SFAs) reduce fat storage-inducing transmembrane protein 2 (FIT2)-facilitated, pancreatic ß cell LD biogenesis, which in turn induces ß cell dysfunction and death, leading to diabetes. This mechanism involves direct acylation of FIT2 cysteine residues, which then marks the FIT2 protein for endoplasmic reticulum (ER)-associated degradation. Loss of ß cell FIT2 and LDs reduces insulin secretion, increases intracellular ceramides, stimulates ER stress, and exacerbates diet-induced diabetes in mice. While palmitate and stearate degrade FIT2, unsaturated fatty acids such as palmitoleate and oleate do not, results of which extend to nutrition and diabetes.


Asunto(s)
Diabetes Mellitus/etiología , Diabetes Mellitus/metabolismo , Células Secretoras de Insulina/metabolismo , Gotas Lipídicas/metabolismo , Metabolismo de los Lípidos , Proteínas de la Membrana/genética , Animales , Línea Celular , Estrés del Retículo Endoplásmico , Ácidos Grasos/metabolismo , Glucosa/metabolismo , Intolerancia a la Glucosa , Proteínas de la Membrana/metabolismo , Ratones , Mutación , Palmitatos/metabolismo , Estearatos/metabolismo
4.
Small ; 20(25): e2310791, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38214692

RESUMEN

The evolution of porous membranes has revitalized their potential application in sustainable osmotic-energy conversion. However, the performance of multiporous membranes deviates significantly from the linear extrapolation of single-pore membranes, primarily due to the occurrence of ion-concentration polarization (ICP). This study proposes a robust strategy to overcome this challenge by incorporating photoelectric responsiveness into permselective membranes. By introducing light-induced electric fields within the membrane, the transport of ions is accelerated, leading to a reduction in the diffusion boundary layer and effectively mitigating the detrimental effects of ICP. The developed photoelectric-responsive covalent-organic-framework membranes exhibit an impressive output power density of 69.6 W m-2 under illumination, surpassing the commercial viability threshold by ≈14-fold. This research uncovers a previously unexplored benefit of integrating optical electric conversion with reverse electrodialysis, thereby enhancing energy conversion efficiency.

5.
Glob Chang Biol ; 30(4): e17279, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38619007

RESUMEN

There are close links between solar UV radiation, climate change, and plastic pollution. UV-driven weathering is a key process leading to the degradation of plastics in the environment but also the formation of potentially harmful plastic fragments such as micro- and nanoplastic particles. Estimates of the environmental persistence of plastic pollution, and the formation of fragments, will need to take in account plastic dispersal around the globe, as well as projected UV radiation levels and climate change factors.


Asunto(s)
Energía Solar , Rayos Ultravioleta , Rayos Ultravioleta/efectos adversos , Cambio Climático , Contaminación Ambiental , Tiempo (Meteorología)
6.
Microb Cell Fact ; 23(1): 179, 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38890717

RESUMEN

BACKGROUND: Human lysozyme (hLYZ) is a natural antibacterial protein with broad applications in food and pharmaceutical industries. Recombinant production of hLYZ in Komagataella phaffii (K. phaffii) has attracted considerable attention, but there are very limited strategies for its hyper-production in yeast. RESULTS: Here through Atmospheric and Room Temperature Plasma (ARTP)-based mutagenesis and transcriptomic analysis, the expression of two genes MYO1 and IQG1 encoding the cytokinesis core proteins was identified downregulated along with higher hLYZ production. Deletion of either gene caused severe cytokinesis defects, but significantly enhanced hLYZ production. The highest hLYZ yield of 1,052,444 ± 23,667 U/mL bioactivity and 4.12 ± 0.11 g/L total protein concentration were obtained after high-density fed-batch fermentation in the Δmyo1 mutant, representing the best production of hLYZ in yeast. Furthermore, O-linked mannose glycans were characterized on this recombinant hLYZ. CONCLUSIONS: Our work suggests that cytokinesis-based morphology engineering is an effective way to enhance the production of hLYZ in K. phaffii.


Asunto(s)
Muramidasa , Proteínas Recombinantes , Saccharomycetales , Muramidasa/metabolismo , Muramidasa/genética , Muramidasa/biosíntesis , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Saccharomycetales/metabolismo , Saccharomycetales/genética , Humanos , Fermentación , Citocinesis , Ingeniería Metabólica/métodos , Técnicas de Cultivo Celular por Lotes
7.
Photochem Photobiol Sci ; 23(4): 629-650, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38512633

RESUMEN

This Assessment Update by the Environmental Effects Assessment Panel (EEAP) of the United Nations Environment Programme (UNEP) considers the interactive effects of solar UV radiation, global warming, and other weathering factors on plastics. The Assessment illustrates the significance of solar UV radiation in decreasing the durability of plastic materials, degradation of plastic debris, formation of micro- and nanoplastic particles and accompanying leaching of potential toxic compounds. Micro- and nanoplastics have been found in all ecosystems, the atmosphere, and in humans. While the potential biological risks are not yet well-established, the widespread and increasing occurrence of plastic pollution is reason for continuing research and monitoring. Plastic debris persists after its intended life in soils, water bodies and the atmosphere as well as in living organisms. To counteract accumulation of plastics in the environment, the lifetime of novel plastics or plastic alternatives should better match the functional life of products, with eventual breakdown releasing harmless substances to the environment.


Asunto(s)
Plásticos , Contaminantes Químicos del Agua , Humanos , Plásticos/toxicidad , Ecosistema , Rayos Ultravioleta , Cambio Climático , Contaminantes Químicos del Agua/análisis
8.
Chin J Traumatol ; 27(2): 83-90, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37625936

RESUMEN

PURPOSE: In patients with heatstroke, disseminated intravascular coagulation (DIC) is associated with greater risk of in-hospital mortality. However, time-consuming assays or a complex diagnostic system may delay immediate treatment. Therefore, the present study proposes a new heatstroke-induced coagulopathy (HIC) score in patients with heat illness as an early warning indicator for DIC. METHODS: This retrospective study enrolled patients with heat illness in 24 Chinese hospitals from March 2021 to May 2022. Patients under 18 years old, with a congenital clotting disorder or liver disease, or using anticoagulants were excluded. Data were collected on demographic characteristics, routine blood tests, conventional coagulation assays and biochemical indexes. The risk factors related to coagulation function in heatstroke were identified by regression analysis, and used to construct a scoring system for HIC. The data of patients who met the diagnostic criteria for HIC and International Society on Thrombosis and Haemostasis defined-DIC were analyzed. All statistical analyses were performed using SPSS 26.0. RESULTS: The final analysis included 302 patients with heat illness, of whom 131 (43.4%) suffered from heatstroke, including 7 death (5.3%). Core temperature (OR = 1.681, 95% CI 1.291 - 2.189, p < 0.001), prothrombin time (OR = 1.427, 95% CI 1.175 - 1.733, p < 0.001) and D-dimer (OR = 1.242, 95% CI 1.049 - 1.471, p = 0.012) were independent risk factors for heatstroke, and therefore used to construct an HIC scoring system because of their close relation with abnormal coagulation. A total score ≥ 3 indicated HIC, and HIC scores correlated with the score for International Society of Thrombosis and Hemostasis -DIC (r = 0.8848, p < 0.001). The incidence of HIC (27.5%) was higher than that of DIC (11.2%) in all of 131 heatstroke patients. Meanwhile, the mortality rate of HIC (19.4%) was lower than that of DIC (46.7%). When HIC developed into DIC, parameters of coagulation dysfunction changed significantly: platelet count decreased, D-dimer level rose, and prothrombin time and activated partial thromboplastin time prolonged (p < 0.05). CONCLUSIONS: The newly proposed HIC score may provide a valuable tool for early detection of HIC and prompt initiation of treatment.


Asunto(s)
Trastornos de la Coagulación Sanguínea , Coagulación Intravascular Diseminada , Golpe de Calor , Trombosis , Humanos , Adolescente , Estudios Retrospectivos , Coagulación Intravascular Diseminada/diagnóstico , Coagulación Intravascular Diseminada/epidemiología , Coagulación Intravascular Diseminada/etiología , Trastornos de la Coagulación Sanguínea/diagnóstico , Trastornos de la Coagulación Sanguínea/epidemiología , Trastornos de la Coagulación Sanguínea/etiología , Golpe de Calor/complicaciones
9.
Fa Yi Xue Za Zhi ; 40(1): 20-29, 2024 Feb 25.
Artículo en Inglés, Zh | MEDLINE | ID: mdl-38500457

RESUMEN

OBJECTIVES: To explore the context and hotspot changes of forensic mixed stain research through bibliometric approach. METHODS: The literature of forensic mixed stain included in the core collection of Web of Science database from 2011 to 2022 were collected as the study object, and the annual publication number, countrie (region), institution, journal, keywords, etc. were bibliometrically and visually analyzed using the R-based Bibliometrix 1.1.6 package and VOSviewer 1.6.18 software. RESULTS: A total of 732 articles on forensic mixed stain were included from 2011 to 2022, with the annual number of articles published and the annual citation frequency showing a steady increase year by year. Among the 59 countries (regions) with the most published articles, the United States ranked first with 246 articles, followed by China with 153 articles. The literature came from 104 journals, and the total number of articles published in the top 10 journals was 633. FORENSIC SCI INT GENET ranked first with 307 articles. Visual analysis using VOSviewer software showed that keywords could be divided into four research clusters, namely the genetic marker development group (blue), the mixed stain typing analysis theory group (red), the sequencing analysis group (yellow), and the case sample research group (green). It can be divided into four development stages in terms of different time periods: early development (2011-2013), middle development (2014-2016), rapid development (2017-2020) and latest development (2021-2022). CONCLUSIONS: The number of publications by domestic and foreign scholars in the study of mixed stain in forensic science is showing a relatively stable trend. Machine learning, next generation sequencing and other research have been the hottest topics that have attracted the most attention in recent years, which is expected to further develop the theory of mixed stain typing and sequencing analysis in forensic mixed stain research.


Asunto(s)
Bibliometría , Colorantes , China , Ciencias Forenses , Secuenciación de Nucleótidos de Alto Rendimiento
10.
Angew Chem Int Ed Engl ; 63(5): e202317626, 2024 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-38085222

RESUMEN

Sulfoxides are widely used in the pharmaceutical industry and as ligands in asymmetric catalysis. However, the efficient asymmetric synthesis of this structural motif remains limited. In this study, we disclosed a Ni-catalyzed enantioconvergent reaction that utilizes both racemic allenyl carbonates and ß-sulfinyl esters. Our method employs cheap and more sustainable Ni(II) as a precatalyst and successfully overcomes the challenging poisoning effect and instability of sulfenate generated in situ. This enables the synthesis of a series of dienyl sulfoxides with enantioselectivity of up to 98 % ee. The product exhibits tremendous potential in various applications, including diastereoselective Diels-Alder reactions, coordination with transition metals, and incorporation into medicinal compounds, among others. Using a combination of experimental and computational methods, we have uncovered an interesting associated outersphere mechanism that contrasts with conventional mechanisms commonly observed in asymmetric transition metal catalysis.

11.
J Cell Physiol ; 238(6): 1275-1287, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36960573

RESUMEN

Autism Spectrum Disorder (ASD) is a series of complex neurodevelopmental disorders, which can affect children's social, behavioral and communication abilities. A member of the Sirtuins family of NAD + dependent deacetylases called SIRT2 could regulate the inflammation progress during stress, but the relevant mechanism has not been clearly defined. In the present study, the ASD model of wild type and SIRT2 knock out mice was established to evaluate the impact on the homeostasis of neurons in the hippocampus using western blotting, immunofluorescence and Nissl staining. The results showed that the amplification of neuronal richness was significantly decreased and neuroinflammation increased in the hippocampus following ASD due to autophagy, caused by enhancing the acetylation of FoxO1 using SIRT2 gene deletion and indicating this should be the target for ASD or other psychological stress treatment.


Asunto(s)
Trastorno del Espectro Autista , Autofagia , Proteína Forkhead Box O1 , Hipocampo , Sirtuina 2 , Animales , Ratones , Acetilación , Trastorno del Espectro Autista/genética , Hipocampo/metabolismo , Ratones Noqueados , Sirtuina 2/genética , Sirtuina 2/metabolismo , Proteína Forkhead Box O1/metabolismo
12.
J Transl Med ; 21(1): 427, 2023 06 30.
Artículo en Inglés | MEDLINE | ID: mdl-37386574

RESUMEN

BACKGROUND: Inflammation and immune dysfunction with classically activated macrophages(M1) infiltration are important mechanisms in the progression of atherosclerosis (AS). Dynamin-related protein 1 (DRP1)-dependent mitochondrial fission is a novel target for alleviating inflammatory diseases. This study aimed to investigate the effects of DRP1 inhibitor Mdivi-1 on AS. METHODS: ApoE-/- mice were fed with a high-fat diet supplemented with or without Mdivi-1. RAW264.7 cells were stimulated by ox-LDL, pretreated with or without MCC950, Mito-TEMPO, or Mdivi-1. The burden of plaques and foam cell formation were determined using ORO staining. The blood lipid profles and inflammatory cytokines in serum were detected by commercial kits and ELISA, respectively. The mRNA expression of macrophage polarization markers, activation of NLRP3 and the phosphorylation state of DRP1 were detected. Mitochondrial reactive oxygen species (mito-ROS), mitochondrial staining, ATP level and mitochondrial membrane potential were detected by mito-SOX, MitoTracker, ATP determination kit and JC-1 staining, respectively. RESULTS: In vivo, Mdivi-1 reduced the plaque areas, M1 polarization, NLRP3 activation and DRP1 phosphorylation at Ser616. In vitro, oxidized low-density lipoprotein (ox-LDL) triggered M1 polarization, NLRP3 activation and abnormal accumulation of mito-ROS. MCC950 and Mito-TEMPO suppressed M1 polarization mediated foam cell formation. Mito-TEMPO significantly inhibited NLRP3 activation. In addition, Mdivi-1 reduced foam cells by inhibiting M1 polarization. The possible mechanisms responsible for the anti-atherosclerotic effects of Mdivi-1 on reducing M1 polarization were associated with suppressing mito-ROS/NLRP3 pathway by inhibiting DRP1 mediated mitochondrial fission. In vitro, similar results were observed by DRP1 knockdown. CONCLUSION: Inhibition of DRP1-dependent mitochondrial fission by Mdivi-1 alleviated atherogenesis via suppressing mito-ROS/NLRP3-mediated M1 polarization, indicating DRP1-dependent mitochondrial fission as a potential therapeutic target for AS.


Asunto(s)
Aterosclerosis , Indenos , Animales , Ratones , Dinámicas Mitocondriales , Proteína con Dominio Pirina 3 de la Familia NLR , Especies Reactivas de Oxígeno , Aterosclerosis/tratamiento farmacológico , Dinaminas , Furanos , Adenosina Trifosfato
13.
J Transl Med ; 21(1): 726, 2023 10 16.
Artículo en Inglés | MEDLINE | ID: mdl-37845765

RESUMEN

OBJECTIVES: Gastrointestinal stromal tumors (GISTs) carrying different KIT exon 11 (KIT-11) mutations exhibit varying prognoses and responses to Imatinib. Herein, we aimed to determine whether computed tomography (CT) radiomics can accurately stratify KIT-11 mutation genotypes to benefit Imatinib therapy and GISTs monitoring. METHODS: Overall, 1143 GISTs from 3 independent centers were separated into a training cohort (TC) or validation cohort (VC). In addition, the KIT-11 mutation genotype was classified into 4 categories: no KIT-11 mutation (K11-NM), point mutations or duplications (K11-PM/D), KIT-11 557/558 deletions (K11-557/558D), and KIT-11 deletion without codons 557/558 involvement (K11-D). Subsequently, radiomic signatures (RS) were generated based on the arterial phase of contrast CT, which were then developed as KIT-11 mutation predictors using 1408 quantitative image features and LASSO regression analysis, with further evaluation of its predictive capability. RESULTS: The TC AUCs for K11-NM, K11-PM/D, K11-557/558D, and K11-D ranged from 0.848 (95% CI 0.812-0.884), 0.759 (95% CI 0.722-0.797), 0.956 (95% CI 0.938-0.974), and 0.876 (95% CI 0.844-0.908), whereas the VC AUCs ranged from 0.723 (95% CI 0.660-0.786), 0.688 (95% CI 0.643-0.732), 0.870 (95% CI 0.824-0.918), and 0.830 (95% CI 0.780-0.878). Macro-weighted AUCs for the KIT-11 mutant genotype ranged from 0.838 (95% CI 0.820-0.855) in the TC to 0.758 (95% CI 0.758-0.784) in VC. TC had an overall accuracy of 0.694 (95%CI 0.660-0.729) for RS-based predictions of the KIT-11 mutant genotype, whereas VC had an accuracy of 0.637 (95%CI 0.595-0.679). CONCLUSIONS: CT radiomics signature exhibited good predictive performance in estimating the KIT-11 mutation genotype, especially in prediction of K11-557/558D genotype. RS-based classification of K11-NM, K11-557/558D, and K11-D patients may be an indication for choice of Imatinib therapy.


Asunto(s)
Tumores del Estroma Gastrointestinal , Humanos , Tumores del Estroma Gastrointestinal/diagnóstico por imagen , Tumores del Estroma Gastrointestinal/tratamiento farmacológico , Tumores del Estroma Gastrointestinal/genética , Genotipo , Mesilato de Imatinib , Mutación/genética , Proteínas Proto-Oncogénicas c-kit/genética , Proteínas Tirosina Quinasas Receptoras , Estudios Retrospectivos
14.
Chemistry ; 29(63): e202302460, 2023 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-37605607

RESUMEN

Insufficient access to clean water and resources has emerged as one of the most pressing issues affecting people globally. Membrane-based ion separation has become a focal point of research for the generation of fresh water and the extraction of energy elements. This Review encapsulates recent advancements in the selective ion transport of covalent organic framework (COF) membranes, accomplished by strategically pairing diverse monomers to create membranes with various pore sizes and environments for specific purposes. We first discuss the merits of using COF materials as a basis for fabricating membranes for ion separation. We then explore the development of COF membranes in areas such as desalination, acid recovery, and energy element extraction, with a particular emphasis on the fundamental principles of membrane design. Lastly, we address both theoretical and practical challenges, as well as potential opportunities in the targeted design of ion-selective membranes. The goal of this Review is to stimulate future investigative efforts in this field, which is of significant scientific and strategic importance.

15.
BMC Cancer ; 23(1): 41, 2023 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-36631788

RESUMEN

OBJECTIVE: Due to inconsistency in neoadjuvant chemotherapy (NACT) response in advanced gastric cancer (GC), the indications remain the source of controversy. This study focused on identifying factors related to NACT chemosensitivity and providing the best treatment for GC cases. METHODS: Clinical data in 867 GC cases treated with neoadjuvant chemotherapy were downloaded from two medical centers between January 2014 and December 2020, and analyzed by logistic regression and the least absolute shrinkage and selection operator (LASSO) for identifying potential factors that predicted NACT response and might be incorporated in constructing the prediction nomogram. RESULTS: After the inclusion and exclusion criteria were applied, totally 460 cases were enrolled, among which, 307 were males (66.74%) whereas 153 were females (33.26%), with the age of 24-77 (average, 59.37 ± 10.60) years. Consistent with RECIST standard, 242 patients were classified into effective group (PR or CR) while 218 were into ineffective group (PD or SD), with the effective rate of 52.61%. In training set, LASSO and logistic regression analysis showed that five risk factors were significantly associated with NACT effectiveness, including tumor location, Smoking history, T and N stages, and differentiation. In terms of our prediction model, its C-index was 0.842. Moreover, calibration curve showed that the model-predicted results were in good consistence with actual results. Validation based on internal and external validation sets exhibited consistency between training set results and ours. CONCLUSIONS: This study identified five risk factors which were significantly associated with NACT response, including smoking history, clinical T stage, clinical N stage, tumor location and differentiation. The prediction model that exhibited satisfying ability to predict NACT effectiveness was constructed, which may be adopted for identifying the best therapeutic strategy for advanced GC by gastrointestinal surgeons.


Asunto(s)
Neoplasias Gástricas , Masculino , Femenino , Humanos , Persona de Mediana Edad , Anciano , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/patología , Terapia Neoadyuvante , Estudios de Cohortes , Nomogramas , Quimioterapia Adyuvante
16.
Ann Bot ; 131(7): 1061-1072, 2023 08 25.
Artículo en Inglés | MEDLINE | ID: mdl-36454654

RESUMEN

BACKGROUND AND AIMS: Abiotic and biotic factors simultaneously affect tree growth and thus shape community structure and dynamics. In particular, trees of different size classes show different growth responses to soil nutrients and neighbourhood crowding, but our understanding of how species' joint responses to these factors vary between size classes remains limited in multi-storied temperate forests. Here, we investigated size class differences in tree growth response to soil gradients and neighbourhood crowding in an old-growth temperate forest. METHODS: We combined growth data over 15 years from 38 902 individuals of 42 tree species with trait data in a 25-ha temperate forest plot in northeast China. We built hierarchical Bayesian models of tree growth to examine the effects of soil gradients and neighbourhood crowding between size classes and canopy types. KEY RESULTS: We found that soil and neighbours mainly acted separately in shaping tree growth in small and large trees. Soil total nitrogen and phosphorus increased tree growth in small trees, in particular of understorey species, but not in large trees. Neighbours reduced tree growth in both tree size classes, with stronger effects on large than small trees, and on canopy than understorey species. Furthermore, small trees with higher specific leaf area grew faster in fertile soils, and small trees with less seed mass grew faster in crowded environments. Large trees with higher specific leaf area, specific root length and less seed mass grew faster in crowded environments, while these traits had limited influence on tree growth response to soil gradients. CONCLUSIONS: Our study highlights the importance of size class in modulating the response of tree growth to soil and neighbours, and the differential role of species canopy types and functional traits in capturing these effects in large vs. small trees.


Asunto(s)
Bosques , Suelo , Teorema de Bayes , China , Fenotipo
17.
Org Biomol Chem ; 21(15): 3096-3100, 2023 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-36974750

RESUMEN

Activated vinylcyclopropanes can form zwitterionic π-allylmetal species in the presence of transition metals and are widely used in organic synthesis. A nickel-catalyzed asymmetric allylation of secondary phosphine oxides with vinylcyclopropanes was described. Tertiary phosphine oxide products could be obtained with up to 91% yield and 92% ee.

18.
Environ Sci Technol ; 57(25): 9174-9183, 2023 06 27.
Artículo en Inglés | MEDLINE | ID: mdl-37311089

RESUMEN

Plastic film mulching and urea nitrogen fertilization are widely used in agricultural ecosystems, but both their long-term use may leave a negative legacy on crop growth, due to deleterious effects of plastic and microplastic accumulation and acidification in soil, respectively. Here, we stopped covering soil with a plastic film in an experimental site that was previously covered for 33 years and compared soil properties and subsequent maize growth and yield between plots that were previously and never covered with the plastic film. Soil moisture was about 5-16% higher at the previously mulched plot than at the never-mulched plot, but NO3- content was lower for the former when with fertilization. Maize growth and yield were generally similar between previously and never-mulched plots. Maize had an earlier dough stage (6-10 days) in previously mulched compared to never-mulched plots. Although plastic film mulching did add substantial amounts of film residues and microplastic accumulation into soils, it did not leave a net negative legacy (given the positive effects of the mulching practice in the first place) for soil quality and subsequent maize growth and yield, at least as an initial effect in our experiment. Long-term urea fertilization resulted in a pH decrease of about 1 unit, which bring a temporary maize P deficiency occurring in early stages of growth. Our data add long-term information on this important form of plastic pollution in agricultural systems.


Asunto(s)
Plásticos , Suelo , Suelo/química , Zea mays , Nitrógeno/análisis , Microplásticos , Ecosistema , Agua , Agricultura , Urea , Fertilización , China
19.
J Appl Microbiol ; 134(7)2023 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-37429605

RESUMEN

AIMS: Study of the effect of isoleucine on the biosynthesis of FK506 and modification of its producing strain to improve the production of FK506. METHODS AND RESULTS: Metabolomics analysis was conducted to explore key changes in the metabolic processes of Streptomyces tsukubaensis Δ68 in medium with and without isoleucine. In-depth analysis revealed that the shikimate pathway, methylmalonyl-CoA, and pyruvate might be the rate-limiting factors in FK506 biosynthesis. Overexpression of involved gene PCCB1 in S. tsukubaensis Δ68, a high-yielding strain Δ68-PCCB1 was generated. Additionally, the amino acids supplement was further optimized to improve FK506 biosynthesis. Finally, FK506 production was increased to 929.6 mg L-1, which was 56.6% higher than that in the starter strain, when supplemented isoleucine and valine at 9 and 4 g L-1, respectively. CONCLUSIONS: Methylmalonyl-CoA might be the key rate-limiting factors in FK506 biosynthesis and overexpression of the gene PCCB1 and further addition of isoleucine and valine could increase the yield of FK506 by 56.6%.


Asunto(s)
Inmunosupresores , Tacrolimus , Tacrolimus/química , Tacrolimus/metabolismo , Ingeniería Metabólica , Isoleucina , Valina
20.
J Appl Microbiol ; 134(10)2023 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-37873659

RESUMEN

AIMS: We evaluated whether the randomness of mutation breeding can be regulated through a double-reporter system. We hope that by establishing a new precursor feeding strategy, the production capacity of industrial microorganisms after pilot scale-up can be further improved. METHODS AND RESULTS: In this study, the industrial strain Streptomyces roseosporus L2796 was used as the starter strain for daptomycin production, and a double-reporter system with the kanamycin resistance gene Neo and the chromogenic gene gusA was constructed to screen for high-yield strain L2201 through atmospheric and room temperature plasma (ARTP). Furthermore, the composition of the culture medium and the parameters of precursor replenishment were optimized, resulting in a significant enhancement of the daptomycin yield of the mutant strain L2201(752.67 mg/l). CONCLUSIONS: This study successfully screened a high-yield strain of daptomycin through a double-reporter system combined with ARTP mutation. The expression level of two reporter genes can evaluate the strength of dptEp promoter, which can stimulate the expression level of dptE in the biosynthesis of daptomycin, thus producing more daptomycin. The developed multi-stage feeding rate strategy provides a novel way to increase daptomycin in industrial fermentation.


Asunto(s)
Daptomicina , Streptomyces , Fermentación , Mutagénesis , Mutación , Streptomyces/genética , Streptomyces/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA