Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 416
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Nano Lett ; 24(12): 3750-3758, 2024 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-38488747

RESUMEN

Semiconductor planar nanowire arrays (PNAs) are essential for achieving large-scale device integration. Direct heteroepitaxy of PNAs on a flat substrate is constrained by the mismatch in crystalline symmetry and lattice parameters between the substrate and epitaxial nanowires. This study presents a novel approach termed "self-competitive growth" for heteroepitaxy of CsPbBr3 PNAs on mica. The key to inducing the self-competitive growth of CsPbBr3 PNAs on mica involves restricting the nucleation of CsPbBr3 nanowires in a high-adsorption region, which is accomplished by overlaying graphite sheets on the mica surface. Theoretical calculations and experimental results demonstrate that CsPbBr3 nanowires oriented perpendicular to the boundary of the high-adsorption area exhibit greater competitiveness in intercepting the growth of nanowires in the other two directions, resulting in PNAs with a consistent orientation. Moreover, these PNAs exhibit low-threshold and stable amplified spontaneous emission under one-, two-, and three-photon excitation, indicating their potential for an integrated laser array.

2.
Appl Environ Microbiol ; : e0208223, 2024 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-38899886

RESUMEN

Genetic engineering at the genomic scale provides a rapid means to evolve microbes for desirable traits. However, in many filamentous fungi, such trials are daunted by low transformation efficiency. Differentially expressed genes under certain conditions may contain important regulatory factors. Accordingly, although manipulating these subsets of genes only can largely reduce the time and labor, engineering at such a sub-genomic level may also be able to improve the microbial performance. Herein, first using the industrially important cellulase-producing filamentous fungus Trichoderma reesei as a model organism, we constructed suppression subtractive hybridization (SSH) libraries enriched with differentially expressed genes under cellulase induction (MM-Avicel) and cellulase repression conditions (MM-Glucose). The libraries, in combination with RNA interference, enabled sub-genomic engineering of T. reesei for enhanced cellulase production. The ability of T. reesei to produce endoglucanase was improved by 2.8~3.3-fold. In addition, novel regulatory genes (tre49304, tre120391, and tre123541) were identified to affect cellulase expression in T. reesei. Iterative manipulation using the same strategy further increased the yield of endoglucanase activity to 75.6 U/mL, which was seven times as high as that of the wild type (10.8 U/mL). Moreover, using Humicola insolens as an example, such a sub-genomic RNAi-assisted strain evolution proved to be also useful in other industrially important filamentous fungi. H. insolens is a filamentous fungus commonly used to produce catalase, albeit with similarly low transformation efficiency and scarce knowledge underlying the regulation of catalase expression. By combining SSH and RNAi, a strain of H. insolens producing 28,500 ± 288 U/mL of catalase was obtained, which was 1.9 times as high as that of the parent strain.IMPORTANCEGenetic engineering at the genomic scale provides an unparalleled advantage in microbial strain improvement, which has previously been limited only to the organisms with high transformation efficiency such as Saccharomyces cerevisiae and Escherichia coli. Herein, using the filamentous fungus Trichoderma reesei as a model organism, we demonstrated that the advantage of suppression subtractive hybridization (SSH) to enrich differentially expressed genes and the convenience of RNA interference to manipulate a multitude of genes could be combined to overcome the inadequate transformation efficiency. With this sub-genomic evolution strategy, T. reesei could be iteratively engineered for higher cellulase production. Intriguingly, Humicola insolens, a fungus with even little knowledge in gene expression regulation, was also improved for catalase production. The same strategy may also be expanded to engineering other microorganisms for enhanced production of proteins, organic acids, and secondary metabolites.

3.
Opt Express ; 32(9): 14953-14962, 2024 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-38859158

RESUMEN

In this work, we hybridize an air cavity reflector and a nanopatterned sapphire substrate (NPSS) for making an inclined-sidewall-shaped deep ultraviolet micro light-emitting diode (DUV micro-LED) array to enhance the light extraction efficiency (LEE). A cost-effective hybrid photolithography process involving positive and negative photoresist (PR) is explored to fabricate air-cavity reflectors. The experimental results demonstrate a 9.88% increase in the optical power for the DUV micro-LED array with a bottom air-cavity reflector when compared with the conventional DUV micro-LED array with only a sidewall metal reflector. The bottom air-cavity reflector significantly contributes to the reduction of the light absorption and provides more escape paths for light, which in turn increases the LEE. Our investigations also report that such a designed air-cavity reflector exhibits a more pronounced impact on small-size micro-LED arrays, because more photons can propagate into escape cones by experiencing fewer scattering events from the air-cavity structure. Furthermore, the NPSS can enlarge the escape cone and serve as scattering centers to eliminate the waveguiding effect, which further enables the improved LEE for the DUV micro-LED array with an air-cavity reflector.

4.
Gastrointest Endosc ; 2024 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-38851456

RESUMEN

BACKGROUND AND AIMS: Despite the benefits of artificial intelligence (AI) in small bowel (SB) capsule endoscopy (CE) image reading, information on its application in the stomach and SB CE is lacking. METHODS: In this multicenter, retrospective diagnostic study, gastric imaging data were added to the deep learning (DL)-based SmartScan (SS), which has been described previously. A total of 1,069 magnetically controlled gastrointestinal (GI) CE examinations (comprising 2,672,542 gastric images) were used in the training phase for recognizing gastric pathologies, producing a new AI algorithm named SS Plus. 342 fully automated, magnetically controlled CE (FAMCE) examinations were included in the validation phase. The performance of both senior and junior endoscopists with both the SS Plus-Assisted Reading (SSP-AR) and conventional reading (CR) modes was assessed. RESULTS: SS Plus was designed to recognize 5 types of gastric lesions and 17 types of SB lesions. SS Plus reduced the number of CE images required for review to 873.90 (1000) (median, IQR 814.50-1,000) versus 44,322.73 (42,393) (median, IQR 31,722.75-54,971.25) for CR. Furthermore, with SSP-AR, endoscopists took 9.54 min (8.51) (median, IQR 6.05-13.13) to complete the CE video reading. In the 342 CE videos, SS Plus identified 411 gastric and 422 SB lesions, whereas 400 gastric and 368 intestinal lesions were detected with CR. Moreover, junior endoscopists remarkably improved their CE image reading ability with SSP-AR. CONCLUSIONS: Our study shows that the newly upgraded DL-based algorithm SS Plus can detect GI lesions and help improve the diagnostic performance of junior endoscopists in interpreting CE videos.

5.
Fish Shellfish Immunol ; 145: 109330, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38159874

RESUMEN

Thioester-containing proteins (TEPs) play a vital role in the innate immune response to biotic and abiotic stresses. In this study, the TEPs in C. gigas were identified, and their gene structure, phylogenetic relationships, collinearity relationships, expression profiles, sequence diversity, and alternative splicing were analyzed. Eight Tep genes were identified in C. gigas genome. Functional analysis and evolutionary relationships indicated a high level of homology to other mollusks TEPs. The transcriptome quantitative analysis results showed that the Tep genes in C. gigas respond to heat stress and Vibrio stress. Alternative splicing analysis revealed four Tep genes (designated A2M_1, CD109_3, CD109_5, complement C3) encode multiple alternative splice variants. Analysis of gene structure and multiple alignments revealed that seven CD109_5 variants are produced through the alternative splicing of the 19th exon, which encodes the highly variable central region. Sequence diversity analysis revealed thirteen missense variants within the 19th exon region of these seven CD109_5 alternative splice variants. Furthermore, the differential alternative splicing analysis showed significant induction of CD109_5, A2M_1 and A2M_2 variants after infection with V. parahaemolyticus. This study explores the Tep genes of C. gigas, providing insights into the molecular mechanisms underlying the involvement of C. gigas TEPs in innate immunity.


Asunto(s)
Crassostrea , Animales , Filogenia , Perfilación de la Expresión Génica , Inmunidad Innata/genética , Estrés Fisiológico
6.
Fish Shellfish Immunol ; 149: 109533, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38575039

RESUMEN

The Commd (Copper Metabolism gene MURR1 Domain) family genes play crucial roles in various biological processes, including copper and sodium transport regulation, NF-κB activity, and cell cycle progression. Their function in Haliotis discus hannai, however, remains unclear. This study focused on identifying and analyzing the Commd genes in H. discus hannai, including their gene structure, phylogenetic relationships, expression profiles, sequence diversity, and alternative splicing. The results revealed significant homology between H. discus hannai's Commd genes and those of other mollusks. Both transcriptome quantitative analysis and qRT-PCR demonstrated the responsiveness of these genes to heat stress and Vibrio parahaemolyticus infection. Notably, alternative splicing analysis revealed that COMMD2, COMMD4, COMMD5, and COMMD7 produce multiple alternative splice variants. Furthermore, sequence diversity analysis uncovered numerous missense mutations, specifically 9 in COMMD5 and 14 in COMMD10. These findings contribute to expanding knowledge on the function and evolution of the Commd gene family and underscore the potential role of COMMD in the innate immune response of H. discus hannai. This research, therefore, offers a novel perspective on the molecular mechanisms underpinning the involvement of Commd genes in innate immunity, paving the way for further explorations in this field.


Asunto(s)
Gastrópodos , Inmunidad Innata , Filogenia , Vibrio parahaemolyticus , Animales , Vibrio parahaemolyticus/fisiología , Inmunidad Innata/genética , Gastrópodos/inmunología , Gastrópodos/genética , Gastrópodos/microbiología , Estrés Fisiológico/inmunología , Estrés Fisiológico/genética , Familia de Multigenes , Perfilación de la Expresión Génica , Alineación de Secuencia , Secuencia de Aminoácidos , Regulación de la Expresión Génica/inmunología , Evolución Molecular
7.
Environ Sci Technol ; 58(19): 8404-8416, 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38698567

RESUMEN

In densely populated urban areas, PM2.5 has a direct impact on the health and quality of residents' life. Thus, understanding the disparities of PM2.5 is crucial for ensuring urban sustainability and public health. Traditional prediction models often overlook the spillover effects within urban areas and the complexity of the data, leading to inaccurate spatial predictions of PM2.5. We propose Deep Support Vector Regression (DSVR) that models the urban areas as a graph, with grid center points as the nodes and the connections between grids as the edges. Nature and human activity features of each grid are initialized as the representation of each node. Based on the graph, DSVR uses random diffusion-based deep learning to quantify the spillover effects of PM2.5. It leverages random walk to uncover more extensive spillover relationships between nodes, thereby capturing both the local and nonlocal spillover effects of PM2.5. And then it engages in predictive learning using the feature vectors that encapsulate spillover effects, enhancing the understanding of PM2.5 disparities and connections across different regions. By applying our proposed model in the northern region of New York for predictive performance analysis, we found that DSVR consistently outperforms other models. During periods of PM2.5 surges, the R-square of DSVR reaches as high as 0.729, outperforming non-spillover models by 2.5 to 5.7 times and traditional spatial metric models by 2.2 to 4.6 times. Therefore, our proposed model holds significant importance for understanding disparities of PM2.5 air pollution in urban areas, taking the first steps toward a new method that considers both the spillover effects and nonlinear feature of data for prediction.


Asunto(s)
Contaminación del Aire , Material Particulado , Máquina de Vectores de Soporte , Humanos , Contaminantes Atmosféricos/análisis , Ciudades , Monitoreo del Ambiente
8.
Nature ; 559(7715): 575-579, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29995856

RESUMEN

Mitochondrial calcium uptake is critical for regulating ATP production, intracellular calcium signalling, and cell death. This uptake is mediated by a highly selective calcium channel called the mitochondrial calcium uniporter (MCU). Here, we determined the structures of the pore-forming MCU proteins from two fungi by X-ray crystallography and single-particle cryo-electron microscopy. The stoichiometry, overall architecture, and individual subunit structure differed markedly from those described in the recent nuclear magnetic resonance structure of Caenorhabditis elegans MCU. We observed a dimer-of-dimer architecture across species and chemical environments, which was corroborated by biochemical experiments. Structural analyses and functional characterization uncovered the roles of key residues in the pore. These results reveal a new ion channel architecture, provide insights into calcium coordination, selectivity and conduction, and establish a structural framework for understanding the mechanism of mitochondrial calcium uniporter function.


Asunto(s)
Canales de Calcio/química , Canales de Calcio/ultraestructura , Microscopía por Crioelectrón , Fusarium/química , Metarhizium/química , Animales , Caenorhabditis elegans/química , Calcio/metabolismo , Canales de Calcio/metabolismo , Cristalografía por Rayos X , Activación del Canal Iónico , Modelos Moleculares , Dominios Proteicos , Multimerización de Proteína , Subunidades de Proteína/química , Subunidades de Proteína/metabolismo , Reproducibilidad de los Resultados , Solubilidad
9.
Altern Ther Health Med ; 30(1): 58-62, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37773673

RESUMEN

Objective: The objective of this experiment was to investigate the relationship between the circadian rhythm of blood pressure and left ventricular hypertrophy (LVH) in patients with hypertension. Methods: A total of 500 hypertension patients with documented circadian rhythm of blood pressure were selected for this study. The researchers collected general patient data and fasting blood samples. The following parameters were measured within subgroups of hypertensive patients: age, sex ratio, BMI, fasting blood glucose, total cholesterol, triacylglycerol, HDL-C, LDL-C, duration of hypertension, antihypertensive drug usage, and statin intake. Results: The results of the study showed that LVH hypertension had a significantly higher proportion of grade 3 hypertension compared to non-LVH hypertension (P < .001). Additionally, LVH hypertension displayed higher mean systolic blood pressure levels over a 24-hour period (P = .002), during daytime (P = .029), and during nighttime (P < .001). The 24-hour pulse pressure (P < .001) and pulse pressure index (P = 0.001) were also significantly higher in patients with LVH hypertension. Furthermore, the rate of blood pressure decline at night was significantly lower in the LVH hypertension group compared to the control group (P < .001). B-type natriuretic peptide (BNP) levels (P = .034) and left ventricular mass index (LVMI) (P < .001) were significantly higher in patients with LVH hypertension compared to non-LVH patients. Conclusions: The findings of this study suggest a close association between hypertensive LVH and the weakening or disappearance of the circadian rhythm of blood pressure. It was also observed that the level of blood pressure classification and plasma BNP levels were increased in patients with LVH hypertension.


Asunto(s)
Hipertensión , Hipertrofia Ventricular Izquierda , Humanos , Presión Sanguínea , Hipertensión/complicaciones , Antihipertensivos/uso terapéutico , Ritmo Circadiano
10.
Sensors (Basel) ; 24(7)2024 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-38610323

RESUMEN

The mature processes of metal oxide semiconductors (MOS) have attracted considerable interest. However, the low sensitivity of metal oxide semiconductor gas sensors is still challenging, and constrains its practical applications. Bimetallic nanoparticles are of interest owing to their excellent catalytic properties. This excellent feature of bimetallic nanoparticles can solve the problems existing in MOS gas sensors, such as the low response, high operating temperature and slow response time. To enhance acetone sensing performance, we successfully synthesized Au-Pd/ZnO nanorods. In this work, we discovered that Au-Pd nanoparticles modified on ZnO nanorods can remarkably enhance sensor response. The Au-Pd/ZnO gas sensor has long-term stability and an excellent response/recovery process. This excellent sensing performance is attributed to the synergistic catalytic effect of bimetallic AuPd nanoparticles. Moreover, the electronic and chemical sensitization of noble metals also makes a great contribution. This work presents a simple method for preparing Au-Pd/ZnO nanorods and provides a new solution for the detection of acetone based on metal oxide semiconductor.

11.
Int J Mol Sci ; 25(11)2024 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-38891992

RESUMEN

Class III peroxidases (CIII PRXs) are plant-specific enzymes with high activity that play key roles in the catalysis of oxidation-reduction reactions. In plants, CIII PRXs can reduce hydrogen peroxide to catalyze oxidation-reduction reactions, thereby affecting plant growth, development, and stress responses. To date, no systematic analysis of the CIII PRX gene family in litchi (Litchi chinensis Sonn.) has been documented, although the genome has been reported. In this study, a total of 77 CIII PRX (designated LcPRX) gene family members were predicted in the litchi genome to provide a reference for candidate genes in the responses to abiotic stresses during litchi growth and development. All of these LcPRX genes had different numbers of highly conserved PRX domains and were unevenly distributed across fifteen chromosomes. They were further clustered into eight clades using a phylogenetic tree, and almost every clade had its own unique gene structure and motif distribution. Collinearity analysis confirmed that there were eleven pairs of duplicate genes among the LcPRX members, and segmental duplication (SD) was the main driving force behind the LcPRX gene expansion. Tissue-specific expression profiles indicated that the expression levels of all the LcPRX family members in different tissues of the litchi tree were significantly divergent. After different abiotic stress treatments, quantitative real-time PCR (qRT-PCR) analysis revealed that the LcPRX genes responded to various stresses and displayed differential expression patterns. Physicochemical properties, transmembrane domains, subcellular localization, secondary structures, and cis-acting elements were also analyzed. These findings provide insights into the characteristics of the LcPRX gene family and give valuable information for further elucidating its molecular function and then enhancing abiotic stress tolerance in litchi through molecular breeding.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Litchi , Familia de Multigenes , Filogenia , Estrés Fisiológico , Litchi/genética , Litchi/metabolismo , Litchi/enzimología , Estrés Fisiológico/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Genoma de Planta , Peroxidasas/genética , Peroxidasas/metabolismo , Perfilación de la Expresión Génica
12.
Int J Mol Sci ; 25(3)2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38339030

RESUMEN

The MADS-box protein is an important transcription factor in plants and plays an important role in regulating the plant abiotic stress response. In this study, a total of 94 MADS-box genes were predicted in the litchi genome, and these genes were widely distributed on all the chromosomes. The LcMADS-box gene family was divided into six subgroups (Mα, Mß, Mγ, Mδ, MIKC, and UN) based on their phylogenetical relationships with Arabidopsis, and the closely linked subgroups exhibited more similarity in terms of motif distribution and intron/exon numbers. Transcriptome analysis indicated that LcMADS-box gene expression varied in different tissues, which can be divided into universal expression and specific expression. Furthermore, we further validated that LcMADS-box genes can exhibit different responses to various stresses using quantitative real-time PCR (qRT-PCR). Moreover, physicochemical properties, subcellular localization, collinearity, and cis-acting elements were also analyzed. The findings of this study provide valuable insights into the MADS-box gene family in litchi, specifically in relation to stress response. The identification of hormone-related and stress-responsive cis-acting elements in the MADS-box gene promoters suggests their involvement in stress signaling pathways. This study contributes to the understanding of stress tolerance mechanisms in litchi and highlights potential regulatory mechanisms underlying stress responses.


Asunto(s)
Arabidopsis , Litchi , Genoma de Planta , Litchi/genética , Litchi/metabolismo , Proteínas de Dominio MADS/metabolismo , Familia de Multigenes , Filogenia , Arabidopsis/genética , Arabidopsis/metabolismo , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/metabolismo
13.
Zhongguo Zhong Yao Za Zhi ; 49(5): 1310-1317, 2024 Mar.
Artículo en Zh | MEDLINE | ID: mdl-38621978

RESUMEN

This study investigated the effect of Erchen Decoction(ECD) on the prevention of non-alcoholic steatohepatitis(NASH) in mice and explored its possible mechanism, so as to provide scientific data for the clinical application of ECD in the prevention of NASH. C57BL/6 male mice were randomly divided into normal group(methionine and choline supplement, MCS), model group(methionine and choline deficient, MCD), low-dose ECD group(ECD_L, 6 g·kg~(-1)), medium-dose ECD group(ECD_M, 12 g·kg~(-1)), and high-dose ECD group(ECD_H, 24 g·kg~(-1)), with eight mice in each group. The MCS group was fed with an MCS diet, and the other groups were fed with an MCD diet. The mice in each group were given corresponding diets, but the drug intervention group was given low-, medium-, and high-dose ECD(10 mL·kg~(-1)·d~(-1)) by intragastric administration for six weeks on the basis of MCD diet feeding, and the mice could eat and drink freely during the whole experiment. At the end of the experiment, mice were fasted overnight(12 h) and were anesthetized with 20% urethane. Thereafter, the blood and liver tissue were collected. The serum was used to detect the levels of alanine aminotransferase(ALT), aspartate aminotransaminase(AST), interleukin-1ß(IL-1ß), interleukin-6(IL-6), interleukin-10(IL-10), and tumor necrosis factor-α(TNF-α). Liver tissue was processed by hematoxylin-eosin(HE) staining and used for hepatic histological analysis and detection of the expression levels of genes and proteins related to nuclear factor erythroid 2-related factor 2/glutathione peroxidase 4(Nrf2/GPX4) pathway by real-time quantitative reverse transcriptase-polymerase chain reaction(RT-qPCR) and Western blot analysis, respectively. The results showed that compared with the MCS group, the MCD group showed higher serum ALT and AST levels; the HE staining exhibited fat vacuoles and obvious inflammatory cell infiltration in liver tissue; serum IL-1ß, IL-6, and TNF-α levels were significantly increased, and the serum IL-10 level was significantly decreased. The mRNA expressions of fatty acid synthase(FASN), monocyte chemoattractant protein-1(MCP-1), and IL-1ß in liver tissue were significantly up-regulated, while those of GPX4, Nrf2, and NAD(P)H:quinine oxidoreductase(NQO1) were significantly down-regulated. Compared with the MCD group, the serum ALT and AST levels of ECD_M and ECD_H groups were significantly decreased, and the AST level in the ECD_L group was significantly decreased. The number of fat vacuoles and the degree of inflammatory cell infiltration in liver tissue were improved; serum IL-1ß, IL-6, and TNF-α levels were significantly decreased, but the serum IL-10 level was significantly increased only in the ECD_H group. The mRNA expressions of FASN, MCP-1, and IL-1ß in liver tissue were significantly down-regulated, and those of GPX4 and NQO1 were significantly up-regulated. The mRNA expressions of Nrf2 in ECD_M and ECD_H groups were significantly up-regulated. Western blot results showed that compared with the MCD group, the protein expression levels of Nrf2 and GPX4 in each group were significantly increased after ECD administration, and the protein expression level of FASN was significantly decreased; the protein expression of NQO1 was increased in ECD_M and ECD_H groups. In summary, ECD can reduce hepatic lipid accumulation, oxidative stress, liver inflammation, and liver injury in NASH mice, which may be related to the activation of the Nrf2/GPX4 pathway.


Asunto(s)
Enfermedad del Hígado Graso no Alcohólico , Ratones , Masculino , Animales , Enfermedad del Hígado Graso no Alcohólico/etiología , Enfermedad del Hígado Graso no Alcohólico/genética , Metionina/metabolismo , Metionina/farmacología , Interleucina-10/genética , Colina/metabolismo , Colina/farmacología , Colina/uso terapéutico , Factor de Necrosis Tumoral alfa/metabolismo , Interleucina-6/metabolismo , Factor 2 Relacionado con NF-E2/metabolismo , Ratones Endogámicos C57BL , Hígado , Racemetionina/metabolismo , Racemetionina/farmacología , Dieta , ARN Mensajero/metabolismo
14.
Angew Chem Int Ed Engl ; 63(17): e202401575, 2024 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-38357753

RESUMEN

A general approach to the direct deoxygenative transformation of primary, secondary, and tertiary alcohols has been developed. It undergoes through phosphoranyl radical intermediates generated by the addition of exogenous iodine radical to trivalent alkoxylphosphanes. Since these alkoxylphosphanes are readily in situ obtained from alcohols and commercially available, inexpensive chlorodiphenylphosphine, a diverse range of alcohols with various functional groups can be utilized to proceed deoxygenative cross-couplings with alkenes or aryl iodides. The selective transformation of polyhydroxy substrates and the rapid synthesis of complex organic molecules are also demonstrated with this method.

15.
Angew Chem Int Ed Engl ; : e202406767, 2024 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-38682392

RESUMEN

Cyclic sulfones have demonstrated important applications in drug discovery. However, the catalytic and enantioselective synthesis of chiral cyclic sulfones remains challenging. Herein, we develop nickel-catalyzed regiodivergent and enantioselective hydroalkylation of sulfolenes to streamline the synthesis of chiral alkyl cyclic sulfones. The method has broad scope and high functional group tolerance. The regioselectivity can be controlled by ligands only. A neutral PYROX ligand favors C3-alkylation whereas an anionic BOX ligand favors C2-alkylation. This control is kinetic in origin as the C2-bound Ni intermediates are always thermodynamically more stable. Reactivity study of a wide range of relevant Ni intermediates reveal a NiI/NiIII catalytic cycle with a NiII-H species as the resting state. The regio- and enantio-determining step is the insertion of this NiII-H species into 2-sulfolene. This work provides an efficient catalytic method for the synthesis of an important class of organic compounds and enhances the mechanistic understanding of Ni-catalyzed stereoselective hydroalkylation.

16.
Dig Dis Sci ; 68(3): 778-790, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-35705732

RESUMEN

BACKGROUND: Ulcerative colitis (UC) features chronic, non-infectious inflammation of the colon. Insulin-like growth factor binding protein 5 (IGFBP5) has been indicated to be related to various inflammation-related diseases. However, its association with UC remains largely unclear. AIMS: Here, we investigate the role of IGFBP5 in colonic mucosal epithelial cell injury in UC. METHODS: Differentially expressed genes in the colonic tissues of UC mice were screened using the Gene Expression Omnibus database, and IGFBP5 was identified. UC mice were developed using dextran sulfate sodium, and IGFBP5 expression in the colonic tissues of UC mice was confirmed by immunohistochemistry and RT-qPCR. The effects of IGFBP5 in vivo and in vitro were investigated by intraperitoneal injection of adeno-associated virus into UC mice or by transfection with an IGFBP5 overexpression plasmid into lipopolysaccharide-treated colonic mucosal epithelial cells. The mechanisms causing IGFBP5 deletion in UC were predicted by bioinformatics analysis and ChIP-qPCR and verified by rescue experiments. RESULTS: IGFBP5 was reduced in UC. IGFBP5 impaired the NFκB pathway in the colonic tissue of UC mice and ameliorated inflammatory infiltration and colonic mucosal cell injury. IGFBP5 depletion was associated with H3K27me3 modification, which was induced by EZH2. CTCF was responsible for recruiting EZH2 to the promoter region of IGFBP5. CTCF inhibition repressed UC progression by reducing H3K27me3 modification via the discouragement of the enrichment of EZH2 in the IGFBP5 promoter. CONCLUSIONS: CTCF modulates H3K27me3 modification of the IGFBP5 promoter by recruiting EZH2, thereby downregulating IGFBP5 to accentuate colonic mucosal epithelial cell injury in UC mice.


Asunto(s)
Colitis Ulcerosa , Animales , Ratones , Factor de Unión a CCCTC , Colitis Ulcerosa/inducido químicamente , Colitis Ulcerosa/genética , Colitis Ulcerosa/metabolismo , Histonas , Inflamación/metabolismo , Proteína 5 de Unión a Factor de Crecimiento Similar a la Insulina/genética
17.
Appl Microbiol Biotechnol ; 107(11): 3523-3533, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37145161

RESUMEN

L-Alanyl-L-Glutamine (Ala-Gln) is a common parenteral nutritional supplement. In our previous study, the recombinant whole-cell catalyst Escherichia coli BL21(DE3) overexpressing α-amino acid ester acyltransferase (BPA) to produce Ala-Gln has high activity and has been applied to large-scale production experiments. However, the degradation of Ala-Gln is detected under prolonged incubation, and endogenous broad-spectrum dipeptidase may be the primary cause. In this study, a CRISPR-Cas9 method was used to target pepA, pepB, pepD, pepN, dpp, and dtp to knock out one or more target genes. The deletion combination was optimized, and a triple knockout strain BL21(DE3)-ΔpepADN was constructed. The degradation performance of the knockout chassis was measured, and the results showed that the degradation rate of Ala-Gln was alleviated by 48% compared with the control. On this basis, BpADNPA (BPA-ΔpepADN) was built, and the production of Ala-Gln was 129% of the BPA's accumulation, proving that the ΔpepADN knockout conducive to the accumulation of dipeptide. This study will push forward the industrialization process of Ala-Gln production by whole-cell catalyst Escherichia coli expressing α-amino acid ester acyltransferase. KEY POINTS: • Endogenous dipeptidase knockout alleviates the degradation of Ala-Gln by the chassis • The balanced gene knockout combination is pepA, pepD, and pepN • The accumulation of Ala-Gln with BpADNPA was 129% of the control.


Asunto(s)
Aminoácidos , Dipeptidasas , Aminoácidos/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Dipeptidasas/metabolismo , Aciltransferasas/genética , Aciltransferasas/metabolismo , Técnicas de Inactivación de Genes , Dipéptidos/metabolismo , Glutamina/metabolismo
18.
Clin Lab ; 69(10)2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37844059

RESUMEN

BACKGROUND: The most common causes of microcytic hypochromic anemia are thalassemia trait (TT) and iron deficiency anemia (IDA). Clinically, the differential diagnosis of TT and IDA is crucial, but it is typically challenging. Thus, in order to differentiate between TT and IDA, we seek to develop a new discriminative index on an automatic hematology analyzer utilizing the two new RBC characteristics of low hemoglobin density (LHD) and microcytic anemia factor (MAF). METHODS: We recruited a total of 323 subjects, including 115 healthy controls, 83 TT, and 125 IDA. An automated hematology analyzer (DxH800, Beckman Coulter) was used to determine peripheral blood parameters; LHD and MAF were calculated using the parameters of MCHC, Hb, and MCV. The receiver operating characteristic (ROC) curve was used to determine the cutoff values and evaluate the diagnostic value for TT and IDA. RESULTS: LHD was significantly lower in TT than IDA, whereas MAF was higher. To distinguish between TT and IDA, a new formula based on LHD and MAF was developed, with a cutoff value of 0.5, AUC of 0.9706 (95% CI: 0.9503 - 0.9909), and specificity, sensitivity, positive predictive value, and negative predictive values were 92.91%, 91.36%, 89.16%, and 94.40%, respectively. The new formula has proven advantages over conventional indices, such as RDW-SD, MCV, MCH, etc. Conclusions: The RBC parameters LHD and MAF detected by hematology analyzer could be useful for screening for TT and IDA. Our new formula outperforms other discriminant formulas in the literature with high sensitivity and specificity, is simple, rapid, and can aid in early detection and management.


Asunto(s)
Anemia Hipocrómica , Anemia Ferropénica , Talasemia beta , Humanos , Anemia Ferropénica/diagnóstico , Índices de Eritrocitos , Anemia Hipocrómica/diagnóstico , Talasemia beta/diagnóstico , Diagnóstico Diferencial , Hemoglobinas
19.
Curr Microbiol ; 80(5): 149, 2023 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-36971869

RESUMEN

Gut microbiota plays an important role in the health of the host and is usually associated with the physiological processes of animals. Both host-specific factors and environmental factors are involved in the shaping of the gut microbial community, and it is necessary to identify the host-dominated differences in gut microbiota among animal species to better explain how they affect the choice of life history strategies in hosts. Here, striped hamsters Cricetulus barabensis and Djungarian hamsters Phodopus sungorus were housed under the same controlled conditions, and fecal samples were collected to compare gut microbiota. A higher Shannon index was observed in striped hamsters than in Djungarian hamsters. Linear discriminant analysis of effect size showed enrichment of the family Lachnospiraceae and genera Muribaculum and Oscillibacter in striped hamsters, with the enrichment of family Erysipelotrichaceae and genus Turicibacter in Djungarian hamsters. Among the top 10 amplicon sequence variants (ASVs), eight showed significantly different relative abundance between the two hamster species. The positive correlations and average degree in the co-occurrence network of striped hamsters were less than those of Djungarian hamsters, showing different complexity of synergistic effects among the gut bacteria. The gut microbial community of striped hamsters had a higher R2 value than that of Djungarian hamsters when fitted with a neutral community model. These differences have a degree of consistency with the variation in the lifestyles of the two hamster species. The study provides insights into the understanding of gut microbiota and its connections with rodent hosts.


Asunto(s)
Microbioma Gastrointestinal , Phodopus , Cricetinae , Animales , Phodopus/fisiología , Cricetulus
20.
BMC Musculoskelet Disord ; 24(1): 325, 2023 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-37098516

RESUMEN

AIM: To explore the mechanism of the healing of tendon tissue and anti-adhesion, and to discuss the role of the transforming growth factor-ß3 (TGF-ß3)/cAMP response element binding protein-1 (CREB-1) signaling pathway in the healing process of tendons. METHOD: All mice were divided into four groups of 1, 2, 4, and 8 weeks respectively. Each time group was divided into four treatment groups: the amplification group, the inhibition group, the negative group, and the control group. When the tendon injury model was established, the CREB-1 virus was injected into the tendon injury parts. A series of methods such as gait behaviourism, anatomy, histological examination, immunohistochemical examination and collagen staining were employed to assess the tendon healing and the protein expression of TGF-ß3, CREB-1, Smad3/7 and type I/III collagen (COL-I/III). CREB-1 virus was sent to tendon stem cells to assess the protein expression of TGF-ß1, TGF-ß3, CREB-1, COL-I/III by methods such as immunohistochemistry and Western blot. RESULTS: The amplification group showed better gait behaviourism than the inhibition group in the healing process. The amplification group also had less adhesion than the negative group. Hematoxylin-eosin (HE) staining of tendon tissue sections showed that the number of fibroblasts in the amplification group was less than the inhibition group, and the immunohistochemical results indicated that the expression of TGF-ß3, CREB-1, and Smad7 at each time point was higher than the inhibition group. The expression of COL-I/III and Smad3 in the amplification group was lower than the inhibition group at all time points. The collagen staining indicated that the ratio of type I/III collagen in the amplification group was higher than the negative group at 2,4,8 week. The CREB-1 amplification virus could promote the protein expression of TGF-ß3, CREB-1 and inhibit the protein expression of TGF-ß1 and COL-I/III in the tendon stem cells. CONCLUSION: In the process of tendon injury healing, CREB-1 could promote the secretion of TGF-ß3, so as to promote the tendon healing and have the effect of anti-adhesion in tendons. It might provide new intervention targets for anti-adhesion treatment of tendon injuries.


Asunto(s)
Proteína de Unión a Elemento de Respuesta al AMP Cíclico , Traumatismos de los Tendones , Factor de Crecimiento Transformador beta3 , Cicatrización de Heridas , Animales , Ratones , Tendones , Traumatismos de los Tendones/metabolismo , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Transducción de Señal , Factor de Crecimiento Transformador beta3/metabolismo , Ratones Endogámicos C57BL , Masculino , Células Madre , Análisis de la Marcha , Adherencias Tisulares/prevención & control
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA