Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
Mais filtros












Base de dados
Intervalo de ano de publicação
1.
Cell Biol Toxicol ; 40(1): 26, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38691186

RESUMO

Copper ionophore NSC319726 has attracted researchers' attention in treating diseases, particularly cancers. However, its potential effects on male reproduction during medication are unclear. This study aimed to determine whether NSC319726 exposure affected the male reproductive system. The reproductive toxicity of NSC319726 was evaluated in male mice following a continuous exposure period of 5 weeks. The result showed that NSC319726 exposure caused testis index reduction, spermatogenesis dysfunction, and architectural damage in the testis and epididymis. The exposure interfered with spermatogonia proliferation, meiosis initiation, sperm count, and sperm morphology. The exposure also disturbed androgen synthesis and blood testis barrier integrity. NSC319726 treatment could elevate the copper ions in the testis to induce cuproptosis in the testis. Copper chelator rescued the elevated copper ions in the testis and partly restored the spermatogenesis dysfunction caused by NSC319726. NSC319726 treatment also decreased the level of retinol dehydrogenase 10 (RDH10), thereby inhibiting the conversion of retinol to retinoic acid, causing the inability to initiate meiosis. Retinoic acid treatment could rescue the meiotic initiation and spermatogenesis while not affecting the intracellular copper ion levels. The study provided an insight into the bio-safety of NSC319726. Retinoic acid could be a potential therapy for spermatogenesis impairment in patients undergoing treatment with NSC319726.


Assuntos
Cobre , Espermatogênese , Testículo , Tretinoína , Masculino , Animais , Espermatogênese/efeitos dos fármacos , Tretinoína/farmacologia , Cobre/toxicidade , Camundongos , Testículo/efeitos dos fármacos , Testículo/metabolismo , Testículo/patologia , Espermatogônias/efeitos dos fármacos , Espermatogônias/metabolismo , Espermatozoides/efeitos dos fármacos , Espermatozoides/metabolismo , Meiose/efeitos dos fármacos , Epididimo/efeitos dos fármacos , Epididimo/metabolismo , Epididimo/patologia
2.
New Phytol ; 242(5): 2285-2300, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38503725

RESUMO

Bottle gourd (Lagenaria siceraria (Mol.) Strandl.) is an economically important vegetable crop and one of the earliest domesticated crops. However, the population history and genomic diversification of bottle gourd have not been extensively studied. We generated a comprehensive bottle gourd genome variation map from genome sequences of 197 world-wide representative accessions, which enables a genome-wide association study for identifying genomic loci associated with resistance to zucchini yellow mosaic virus, and constructed a bottle gourd pangenome that harbors 1534 protein-coding genes absent in the reference genome. Demographic analyses uncover that domesticated bottle gourd originated in Southern Africa c. 12 000 yr ago, and subsequently radiated to the New World via the Atlantic drift and to Eurasia through the efforts of early farmers in the initial Holocene. The identified highly differentiated genomic regions among different bottle gourd populations harbor many genes contributing to their local adaptations such as those related to disease resistance and stress tolerance. Presence/absence variation analysis of genes in the pangenome reveals numerous genes including those involved in abiotic/biotic stress responses that have been under selection during the world-wide expansion of bottle gourds. The bottle gourd variation map and pangenome provide valuable resources for future functional studies and genomics-assisted breeding.


Assuntos
Variação Genética , Genoma de Planta , Genômica , Genômica/métodos , Cucurbitaceae/genética , Filogenia , Genética Populacional , Resistência à Doença/genética , Genes de Plantas , Estudo de Associação Genômica Ampla , Doenças das Plantas/virologia , Doenças das Plantas/genética
3.
Nat Commun ; 14(1): 5487, 2023 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-37679363

RESUMO

Pepper (Capsicum spp.) is one of the earliest cultivated crops and includes five domesticated species, C. annuum var. annuum, C. chinense, C. frutescens, C. baccatum var. pendulum and C. pubescens. Here, we report a pepper graph pan-genome and a genome variation map of 500 accessions from the five domesticated Capsicum species and close wild relatives. We identify highly differentiated genomic regions among the domesticated peppers that underlie their natural variations in flowering time, characteristic flavors, and unique resistances to biotic and abiotic stresses. Domestication sweeps detected in C. annuum var. annuum and C. baccatum var. pendulum are mostly different, and the common domestication traits, including fruit size, shape and pungency, are achieved mainly through the selection of distinct genomic regions between these two cultivated species. Introgressions from C. baccatum into C. chinense and C. frutescens are detected, including those providing genetic sources for various biotic and abiotic stress tolerances.


Assuntos
Capsicum , Piper nigrum , Capsicum/genética , Domesticação , Verduras , Frutas/genética , Produtos Agrícolas/genética , Cânfora , Mentol
4.
Aquac Nutr ; 2023: 6628805, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37266415

RESUMO

The dietary effects of replacing fish meal with enzymatic cottonseed protein (ECP) on the growth performance, immunity, antioxidant, and intestinal health of Chinese soft-shelled turtles have not been explored. An eight-week feeding trial was conducted with a quadruplicated group of turtles (3.44 ± 0.01 g) that were randomly assigned to 16 cages (0.6 m × 0.6 m × 0.6 m) with 30 turtles that were stocked in each cage. Four dietary groups were fed with diets supplemented with 0, 2%, 4%, and 6% (ECP0 group (control group), ECP2 group, ECP4 group, ECP6 group) of enzymatic cottonseed protein replacing fishmeal. The present study illustrated that the final weight and WG in the ECP2 and ECP4 groups were significantly increased (P < 0.05) compared with the control group. The ECP2, ECP4, and ECP6 groups significantly reduced the feed coefficient (P < 0.05) and significantly increased the SGR (P < 0.05). The serum TP and ALB of the ECP4 group were significantly increased (P < 0.05). The ECP2, ECP4, and ECP6 groups significantly increased the activity of intestinal pepsin (P < 0.05), and the activity of intestinal lipase of the EPC4 group was significantly increased (P < 0.05). The intestinal villus height of the EPC4 group and EPC6 group, the villus width of the EPC2 group and EPC4 group, and the intestinal muscle thickness of the EPC4 group were significantly increased (P < 0.05). At the same time, replacing fishmeal with enzymatic cottonseed protein also affected the intestinal inflammation-related genes compared with the control group. Besides that, the expression of the IL-10 gene in the experimental group was significantly upregulated (P < 0.05). Nevertheless, the expression of TNF-α and IL-8 genes in the ECP2 group and TNF-α and IL-1ß genes in the ECP4 group was significantly downregulated (P < 0.05). In summary, replacing fish meal with enzymatic cottonseed protein positively affects the growth, immunity, and intestinal health of Chinese soft-shelled turtles. The appropriate proportion of enzymatic cottonseed protein to replace fish meal in turtle feed is 4%.

5.
Nat Genet ; 55(5): 852-860, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37024581

RESUMO

Effective utilization of wild relatives is key to overcoming challenges in genetic improvement of cultivated tomato, which has a narrow genetic basis; however, current efforts to decipher high-quality genomes for tomato wild species are insufficient. Here, we report chromosome-scale tomato genomes from nine wild species and two cultivated accessions, representative of Solanum section Lycopersicon, the tomato clade. Together with two previously released genomes, we elucidate the phylogeny of Lycopersicon and construct a section-wide gene repertoire. We reveal the landscape of structural variants and provide entry to the genomic diversity among tomato wild relatives, enabling the discovery of a wild tomato gene with the potential to increase yields of modern cultivated tomatoes. Construction of a graph-based genome enables structural-variant-based genome-wide association studies, identifying numerous signals associated with tomato flavor-related traits and fruit metabolites. The tomato super-pangenome resources will expedite biological studies and breeding of this globally important crop.


Assuntos
Solanum lycopersicum , Solanum , Solanum lycopersicum/genética , Estudo de Associação Genômica Ampla , Genoma de Planta/genética , Melhoramento Vegetal , Solanum/genética , Genômica
6.
Front Plant Sci ; 14: 1124664, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36968423

RESUMO

Nitrogen (N) and phosphorus (P) fertilization significantly affect alfalfa production and chemical composition; however, the effect of combined N and P application on protein fractions and the nonstructural carbohydrate content of alfalfa is not fully understood. This two-year study investigated the effects of N and P fertilization on the protein fractions, nonstructural carbohydrates (NSC), and alfalfa hay yield. Field experiments were carried out using two nitrogen application rates (N60, 60 and N120, 120 kg N ha - 1) and four phosphorus application rates (P0, 0; P50, 50; P100, 100; and P150, 150 kg P ha - 1), total 8 treatment (N60P0, N60P50, N60P100, N60P150, N120P0, N120P50, N120P100 and N120P150). Alfalfa seeds were sown in the spring of 2019, uniformly managed for alfalfa establishment, and tested in the spring of 2021-2022. Results indicated that P fertilization significantly increased the hay yield (3.07-13.43% ranges), crude protein (6.79-9.54%), non-protein nitrogen of crude protein (fraction A) (4.09-6.40%), and NSC content (11.00-19.40%) of alfalfa under the same treatment of N application (p < 0.05), whereas non-degradable protein (fraction C) decreased significantly (6.85-13.30%, p < 0.05). Moreover, increasing N application resulted in a linear increase the content of non-protein N (NPN) (4.56-14.09%), soluble protein (SOLP) (3.48-9.70%), and neutral detergent-insoluble protein (NDIP) (2.75-5.89%) (p < 0.05), whereas acid detergent-insoluble protein (ADIP) content was significantly decreased (0.56-5.06%, p < 0.05). The regression equations for nitrogen and phosphorus application indicated a quadratic relationship between yield and forage nutritive values. Meanwhile, the comprehensive evaluation scores of NSC, nitrogen distribution, protein fractions, and hay yield by principal component analysis (PCA) revealed that the N120P100 treatment had the highest score. Overall, 120 kg N ha - 1 coupled with 100 kg P ha - 1 (N120P100) promoted the growth and development of perennial alfalfa, increased soluble nitrogen compounds and total carbohydrate content, and reduced protein degradation, thus improving the alfalfa hay yield and nutritional quality.

7.
Animals (Basel) ; 13(5)2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36899721

RESUMO

To investigate the effect of poultry by-product meal (PBM) replacing fish meal on the growth and intestinal health of Chinese soft-shelled turtle (Pelodiscus sinensis). Four experimental diets were prepared. Fish meal was replaced by 0 (control group, PBM0), 5% (PBM5), 10% (PBM10), and 15% (PBM15) PBM. Compared to the control group, final body weight, weight gain, and specific growth rate were significantly increased, while feed conversion rate decreased significantly in the PBM10 group (p < 0.05). The PBM15 group significantly increased the moisture content and significantly decreased the ash content of the turtles (p < 0.05). The PBM5 and PBM15 groups significantly decreased the whole-body crude lipid (p < 0.05). The serum glucose content increased significantly in the PBM10 group (p < 0.05). The liver malonaldehyde content significantly decreased in the PBM5 group and in the PBM10 group (p < 0.05). Liver glutamic-oxalacetic transaminase and intestinal pepsin activity were increased significantly in the PBM15 group (p < 0.05). The expression of the intestinal interleukin 10 (IL-10) gene was significantly down-regulated in the PBM10 group and the PBM15 group (p < 0.05), the expression of the intestinal interferon-γ (IFN-γ), interleukin-8 (IL-8), and liver toll-like receptor 4 (TLR4) and toll-like receptor 5 (TLR5) genes were significantly up-regulated in the PBM5 group (p < 0.05). In summary, poultry by-product meal can be used as a protein source to replace fish meal in turtle feed. Based on quadratic regression analysis, the optimal replacement ratio is 7.39%.

8.
C R Biol ; 345(4): 3-13, 2023 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-36847117

RESUMO

Consumers began to complain about the taste of tomato varieties in the late 1990's. Although tomato taste is influenced by environmental and post-harvest conditions, varieties show a large diversity for fruit quality traits. We herein review our past and present research work intended to improve tomato fruit quality. First, results from sensory analysis allowed identifying important traits for consumer preferences. Then, we dissected the genetic control of flavor related traits by mapping several QTL in the last 20 years, and identified the genes corresponding to a few major QTL. Since the availability of the tomato genome sequence, genome-wide association studies were performed on several panels of tomato accessions. We discovered a large number of associations for fruit composition and identified relevant allele combinations for breeding. We then performed a meta-analysis combining the results of several studies. We also checked the inheritance of quality traits at the hybrid level and assessed how genomic prediction could help selecting better tomato varieties.


Les consommateurs ont commencé à se plaindre du goût des variétés de tomates à la fin des années 1990. Bien que le goût de la tomate soit influencé par les conditions de culture et de post-récolte, les variétés présentent une grande diversité pour les caractéristiques de qualité des fruits. Nous passons ici en revue nos travaux de recherche passés et présents destinés à comprendre la diversité génétique et améliorer la qualité des fruits de tomate. Les résultats d'analyses sensorielles ont tout d'abord permis d'identifier les traits importants pour les préférences des consommateurs. Ensuite, nous avons disséqué le contrôle génétique des caractères liés à ces traits, cartographié de nombreux QTL depuis 20 ans et identifié les gènes correspondant à quelques QTL majeurs. Depuis la disponibilité de la séquence du génome de la tomate, des études d'association à l'échelle du génome ont été réalisées sur plusieurs panels d'accessions de tomate. Nous avons découvert un grand nombre d'associations pour la composition des fruits, et identifié les combinaisons d'allèles pertinentes pour la sélection. Nous avons ensuite réalisé une méta-analyse combinant les résultats de plusieurs études. Nous avons également vérifié l'hérédité des caractères de qualité au niveau hybride, et évalué comment la prédiction génomique pourrait aider à sélectionner de meilleures variétés de tomates.


Assuntos
Solanum lycopersicum , Solanum lycopersicum/genética , Estudo de Associação Genômica Ampla , Locos de Características Quantitativas/genética , Frutas/genética , Melhoramento Vegetal
9.
Entropy (Basel) ; 26(1)2023 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-38248144

RESUMO

This paper investigates the complex dynamics of a ratio-dependent predator-prey model incorporating the Allee effect in prey and predator harvesting. To explore the joint effect of the harvesting effort and diffusion on the dynamics of the system, we perform the following analyses: (a) The stability of non-negative constant steady states; (b) The sufficient conditions for the occurrence of a Hopf bifurcation, Turing bifurcation, and Turing-Hopf bifurcation; (c) The derivation of the normal form near the Turing-Hopf singularity. Moreover, we provide numerical simulations to illustrate the theoretical results. The results demonstrate that the small change in harvesting effort and the ratio of the diffusion coefficients will destabilize the constant steady states and lead to the complex spatiotemporal behaviors, including homogeneous and inhomogeneous periodic solutions and nonconstant steady states. Moreover, the numerical simulations coincide with our theoretical results.

10.
Cells ; 11(21)2022 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-36359903

RESUMO

Osteosarcoma (OS) is a highly malignant tumor occurring in bone tissue with a high propensity to metastasize, and its underlying mechanisms remain largely elusive. The OS prognosis is poor, and improving the survival of OS patients remains a challenge. Current treatment methods such as surgical approaches, chemotherapeutic drugs, and immunotherapeutic drugs remain ineffective. As research progresses, targeted therapy is gradually becoming irreplaceable. In this review, several treatment modalities for osteosarcoma, such as surgery, chemotherapy, and immunotherapy, are briefly described, followed by a discussion of targeted therapy, the important targets, and new technologies for osteosarcoma treatment.


Assuntos
Neoplasias Ósseas , Osteossarcoma , Humanos , Neoplasias Ósseas/patologia , Osteossarcoma/patologia , Terapia de Alvo Molecular , Osso e Ossos/patologia , Fatores Imunológicos/uso terapêutico
11.
Cells ; 11(13)2022 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-35805131

RESUMO

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and highly fatal neurodegenerative disease. Although the pathogenesis of ALS remains unclear, increasing evidence suggests that a key contributing factor is mitochondrial dysfunction. Mitochondria are organelles in eukaryotic cells responsible for bioenergy production, cellular metabolism, signal transduction, calcium homeostasis, and immune responses and the stability of their function plays a crucial role in neurons. A single disorder or defect in mitochondrial function can lead to pathological changes in cells, such as an impaired calcium buffer period, excessive generation of free radicals, increased mitochondrial membrane permeability, and oxidative stress (OS). Recent research has also shown that these mitochondrial dysfunctions are also associated with pathological changes in ALS and are believed to be commonly involved in the pathogenesis of the disease. This article reviews the latest research on mitochondrial dysfunction and its impact on the progression of ALS, with specific attention to the potential of novel therapeutic strategies targeting mitochondrial dysfunction.


Assuntos
Esclerose Lateral Amiotrófica , Doenças Neurodegenerativas , Esclerose Lateral Amiotrófica/metabolismo , Cálcio/metabolismo , Humanos , Mitocôndrias/metabolismo , Doenças Neurodegenerativas/metabolismo , Estresse Oxidativo/fisiologia
12.
Plant J ; 111(6): 1609-1625, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35861682

RESUMO

Somatic mutations may alter important traits in tree fruits, such as fruit color, size and maturation date. Autumn Gala (AGala), a somatic mutation from apple cultivar Gala, matures 4 weeks later than Gala. To understand the mechanisms underlying the delayed maturation, RNA-seq analyses were conducted with fruit sampled at 13 (Gala) and 16 (AGala) time-points during their growth and development. Weighted gene co-expression network analysis (WGCNA) of 23 372 differentially expressed genes resulted in 25 WGCNA modules. Of these, modules 1 (r = -0.98, P = 2E-21) and 2 (r = -0.52, P = 0.004), which were suppressed in AGala, were correlated with fruit maturation date. Surprisingly, 77 of the 152 member genes in module 1 were harbored in a 2.8-Mb genomic region on chromosome 6 that was deleted and replaced by a 10.7-kb gypsy-like retrotransposon (Gy-36) from chromosome 7 in AGala. Among the 77 member genes, MdACT7 was the most suppressed (by 10.5-fold) in AGala due to a disruptive 2.5-kb insertion in coding sequence. Moreover, MdACT7 is the exclusive apple counterpart of Arabidopsis ACT7 known of essential roles in plant development, and the functional allele MdACT7, which was lost to the deletion in AGala, was associated with early fruit maturation in 268 apple accessions. Overexpressing alleles MdACT7 and Mdact7 in an Arabidopsis act7 line showed that MdACT7 largely rescued its stunted growth and delayed initial flowering while Mdact7 did not. Therefore, the 2.8-Mb hemizygous deletion is largely genetically causal for fruit maturation delay in AGala, and the total loss of MdACT7 might have contributed to the phenotype.


Assuntos
Arabidopsis , Malus , Arabidopsis/genética , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Malus/metabolismo , Mutação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Retroelementos/genética
13.
Cells ; 11(3)2022 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-35159383

RESUMO

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects upper and lower motor neurons. As there is no effective treatment for ALS, it is particularly important to screen key gene therapy targets. The identifications of microRNAs (miRNAs) have completely changed the traditional view of gene regulation. miRNAs are small noncoding single-stranded RNA molecules involved in the regulation of post-transcriptional gene expression. Recent advances also indicate that miRNAs are biomarkers in many diseases, including neurodegenerative diseases. In this review, we summarize recent advances regarding the mechanisms underlying the role of miRNAs in ALS pathogenesis and its application to gene therapy for ALS. The potential of miRNAs to target diverse pathways opens a new avenue for ALS therapy.


Assuntos
Esclerose Lateral Amiotrófica , MicroRNAs , Doenças Neurodegenerativas , Esclerose Lateral Amiotrófica/metabolismo , Biomarcadores/metabolismo , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Neurônios Motores/patologia , Doenças Neurodegenerativas/metabolismo
14.
Hortic Res ; 2022 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-35039843

RESUMO

Improving fruit quality traits such as metabolic composition remains a challenge for tomato breeders. To better understand the genetic architecture of these traits and decipher the demographic history of the loci controlling tomato quality traits, we applied an innovative approach using multiple haplotype-based analyses, aiming to test the potentials of haplotype based study in association and genomic prediction studies. We performed and compared haplotype vs SNP-based associations (hapQTL) with multi-locus mixed model (MLMM), focusing on tomato fruit weight and metabolite contents (i.e. sugars, organic acids and amino acids). Using a panel of 163 tomato accessions genotyped with 5995 SNPs, we detected a total of 784 haplotype blocks, with an average size of haplotype blocks ~58 kb. A total of 108 significant associations for 26 traits were detected thanks to Haplotype/SNP-based Bayes models. Haplotype-based Bayes model (97 associations) outperformed SNP-based Bayes model (50 associations) and MLMM (53 associations) in identifying marker-trait associations as well as in genomic prediction (especially for those traits with moderate to low heritability). To decipher the demographic history, we identified 24 positive selective sweeps using the integrated haplotype score (iHS). Most of the significant associations for tomato quality traits were located within selective sweeps (54.63% and 71.7% in hapQTL and MLMM models, respectively). Promising candidate genes were identified controlling tomato fruit weight and metabolite contents. We thus demonstrated the benefits of using haplotypes for evolutionary and genetic studies, providing novel insights into tomato quality improvement and breeding history.

15.
Entropy (Basel) ; 23(9)2021 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-34573853

RESUMO

Impeller trimming is an economical method for broadening the range of application of a given pump, but it can destroy operational stability and efficiency. In this study, entropy production theory was utilized to analyze the variation of energy loss caused by impeller trimming based on computational fluid dynamics. Experiments and numerical simulations were conducted to investigate the energy loss and fluid-induced radial forces. The pump's performance seriously deteriorated after impeller trimming, especially under overload conditions. Energy loss in the volute decreased after trimming under part-load conditions but increased under overload conditions, and this phenomenon made the pump head unable to be accurately predicted by empirical equations. With the help of entropy production theory, high-energy dissipation regions were mainly located in the volute discharge diffuser under overload conditions because of the flow separation and the mixing of the main flow and the stalled fluid. The increased incidence angle at the volute's tongue after impeller trimming resulted in more serious flow separation and higher energy loss. Furthermore, the radial forces and their fluctuation amplitudes decreased under all the investigated conditions. The horizontal components of the radial forces in all cases were much higher than the vertical components.

16.
Chemistry ; 26(67): 15446-15460, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32909268

RESUMO

The control over chemical reactivity and selectivity are always pursued. Using non-covalent interactions to achieve efficient and selective catalysis is an essential goal of supramolecular catalysis. Supramolecular catalysis based on cucurbit[n]urils (CB[n]s) possesses distinct characteristics for the unique structure of CB[n]s. CB[n]s are a family of pumpkin-shaped host molecules with various molecular sizes, rigid structures, electronegative portals and wealthy host-guest chemistry. Herein, we summarize the three major mechanisms of CB[n]s based supramolecular catalysis. Owing to the structural properties of CB[n]s, CB[n]s can serve as nanoreactors and steric hindrance to modulate the reactivity of substrates. They can also catalyze the reactions by modulating the reactivity of ionized intermediates. Recent progresses on the CB[n]s based supramolecular catalysis are introduced in this Minireview and the future development in this field is discussed. It is anticipated that this review provides insights into the mechanism of CB[n]s based supramolecular catalysis and may help scientists find new opportunities in this field.

17.
Chem Sci ; 11(5): 1192-1204, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34123243

RESUMO

Organic radicals are important species with single electrons. Because of their open-shell structure, they are widely used in functional materials, such as spin probes, magnetic materials and optoelectronic materials. Owing to the high reactivity of single electrons, they often serve as a key intermediate in organic synthesis. Therefore, tuning the stability of radicals is crucial for their functions. Herein, we summarize covalent and non-covalent approaches to tune the stability of organic radicals through steric effects and tuning the delocalization of spin density. Covalent approaches can tune the stability of radicals effectively and non-covalent approaches benefit from dynamicity and reversibility. It is anticipated that the further development of covalent and non-covalent approaches, as well as the interplay between them, may push the fields forward by enriching new radical materials and radical mediated reactions.

18.
Chem Commun (Camb) ; 55(94): 14127-14130, 2019 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-31690894

RESUMO

The redox property of a ferrocene derivative, the catalyst of Fenton oxidation, is modulated by the host-guest complexation of cucurbit[7]uril. The supramolecularly modulated catalyst significantly accelerates the catalytic oxidation of dye chromophores, thus providing a way to avoid product inhibition and broadening the range of substrates.

19.
Genes (Basel) ; 10(9)2019 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-31470680

RESUMO

Plants grown under highly variable natural light regimes differ strongly from plants grown under constant light (CL) regimes. Plant phenotype and adaptation responses are important for plant biomass and fitness. However, the underlying regulatory mechanisms are still poorly understood, particularly from a transcriptional perspective. To investigate the influence of different light regimes on tomato plants, three dynamic light (DL) regimes were designed, using a CL regime as control. Morphological, photosynthetic, and transcriptional differences after five weeks of treatment were compared. Leaf area, plant height, shoot /root weight, total chlorophyll content, photosynthetic rate, and stomatal conductance all significantly decreased in response to DL regimes. The biggest expression difference was found between the treatment with the highest light intensity at the middle of the day with a total of 1080 significantly up-/down-regulated genes. A total of 177 common differentially expressed genes were identified between DL and CL conditions. Finally, significant differences were observed in the levels of gene expression between DL and CL treatments in multiple pathways, predominantly of plant-pathogen interactions, plant hormone signal transductions, metabolites, and photosynthesis. These results expand the understanding of plant development and photosynthetic regulations under DL conditions by multiple pathways.


Assuntos
Solanum lycopersicum/genética , Luz Solar , Transcriptoma , Clorofila/metabolismo , Regulação da Expressão Gênica de Plantas , Solanum lycopersicum/metabolismo , Solanum lycopersicum/efeitos da radiação , Fotoperíodo , Fotossíntese
20.
Bull Math Biol ; 81(7): 2396-2427, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31089864

RESUMO

We formulate a mathematical model of functional partial differential equations for oncolytic virotherapy which incorporates virus diffusivity, tumor cell diffusion, and the viral lytic cycle based on a basic oncolytic virus dynamics model. We conduct a detailed analysis for the dynamics of the model and carry out numerical simulations to demonstrate our analytic results. Particularly, we establish the positive invariant domain for the [Formula: see text] limit set of the system and show that the model has three spatially homogenous equilibriums solutions. We prove that the spatially uniform virus-free steady state is globally asymptotically stable for any viral lytic period delay and diffusion coefficients of tumor cells and viruses when the viral burst size is smaller than a critical value. We obtain the conditions, for example the ratio of virus diffusion coefficient to that of tumor cells is greater than a value and the viral lytic cycle, is greater than a critical value, under which the spatially uniform positive steady state is locally asymptotically stable. We also obtain conditions under which the system undergoes Hopf bifurcations, and stable periodic solutions occur. We point out medical implications of our results which are difficult to obtain from models without combining diffusive properties of viruses and tumor cells with viral lytic cycles.


Assuntos
Modelos Biológicos , Neoplasias/terapia , Terapia Viral Oncolítica/métodos , Simulação por Computador , Humanos , Conceitos Matemáticos , Neoplasias/patologia , Neoplasias/virologia , Terapia Viral Oncolítica/estatística & dados numéricos , Vírus Oncolíticos/patogenicidade , Vírus Oncolíticos/fisiologia , Replicação Viral
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...