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1.
Food Chem ; 305: 125479, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505418

RESUMO

1-o-Galloylglycerol (GG) was synthesized by the enzymatic glycerolysis of propyl gallate (PG) using a food-grade lipase (Lipozyme® 435). The reaction conditions affecting the yield of GG were optimized and a yield of 76.9% ±â€¯1.2% was obtained. GG was characterized by various techniques after being separated from the reaction mixture using liquid-liquid extraction. The water solubility and hydrophilicity of GG were significantly higher than those of gallic acid (GA) and PG. The antioxidant properties, measured by the ferric reducing antioxidant power (FRAP) and hydrogen peroxide (H2O2) scavenging assays, showed that GG exhibited the highest scavenging capacity (GG > GA > PG). From the results of the 1,1-diphenyl-2-picrylhydrazyl (DPPH•) and 2,2'-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS•+) assays, GG and GA exhibited greater scavenging capacity than PG (GG = GA > PG). These results suggest that GG may be used as a water-soluble antioxidant alternative to GA for food and cosmetic applications.

2.
Anticancer Drugs ; 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31815761

RESUMO

Successive infusion of natural killer cells is increasingly being explored as a treatment for cancer patients. The inadequate homing of natural killer cells into the tumor site resulted in the poor efficacy of natural killer cells on solid tumors. For the adoptive transfer of tumor-directed natural killer cell has been proved effective, it is hypothesized that there must be more association between the tumor-produced chemokines and the natural killer cells-expressed chemokine receptors. Increased CXCL12 and CCL21 could ameliorated colorectal cancer via generating an anti-tumor environment by preferentially attracting natural killer cells which expressed the chemokine receptor CXCR4 and CCR7. This study demonstrated that overexpressed CXCR4 and CCR7 on the surface of NK92 cell enhanced their migration to human colon cells. Moreover, the administration of such natural killer cells resulted in tumor shrinkage and a significantly increased survival of experimental mice when compared to ones undergoing the treatment of xenografts with natural killer cells expressing only the mock control. These suggested that chemokine receptor engineered natural killer cells could be a promising tool to improve adoptive tumor immunotherapy.

3.
Neuron ; 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31668485

RESUMO

Top-down modulation of visual processing is mediated in part by direct prefrontal to visual cortical projections. Here, we show that the mouse cingulate cortex (Cg) regulates visual processing not only through corticocortical neurons projecting to the visual cortex but also through corticotectal neurons projecting subcortically. Bidirectional optogenetic manipulation demonstrated a prominent contribution of Cg corticotectal neurons to visually guided behavior, which is mediated by their collateral projections to both the motor-related layers of the superior colliculus (SC) and the lateral posterior nucleus of the thalamus (LP, analogous to the primate pulvinar). Whereas the Cg innervates the anterior LP (LPa), the SC innervates the posterior LP (LPp). Activating each stage of the Cg→SC→LPp or the Cg→LPa pathway strongly enhanced visual performance of the mouse and the sensory responses of visual cortical neurons. These results delineate two subcortical pathways by which a subtype of prefrontal pyramidal neurons exerts a powerful top-down influence on visual processing.

4.
J Transl Med ; 17(1): 366, 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31711520

RESUMO

BACKGROUND: Myelodysplastic syndrome (MDS) can progress to acute myeloid leukemia (AML), and conventional chemotherapy (decitabine) does not effectively inhibit tumor cells. Enhancer of zeste homologue 2 (EZH2) and Heme oxygenase-1 (HO-1) are two key factors in patients resistance and deterioration. METHODS: In total, 58 MDS patients were divided into four groups. We analyzed the difference in HO-1 and EZH2 expression among the groups by real-time PCR. After treatment with Hemin or Znpp IX, flow cytometry was used to detect apoptosis and assess the cell cycle distribution of tumor cells. Following injection of mice with very high-risk MDS cells, spleen and bone marrow samples were studied by immunohistochemistry (IHC) and hematoxylin and eosin (H&E) staining. MDS cells overexpressing EZH2 and HO-1 were analyzed by high-throughput sequencing. The effect of HO-1 on the pRB-E2F pathway was analyzed by Western blotting. The effects of decitabine on P15INK4B and TP53 in MDS cells after inhibiting HO-1 were detected by Western blotting. RESULTS: Real-time PCR results showed that EZH2 and HO-1 expression levels were higher in MDS patients than in normal donors. The levels of HO-1 and EZH2 were simultaneously increased in the high-risk and very high-risk groups. Linear correlation analysis and laser scanning confocal microscopy results indicated that EZH2 was related to HO-1. MDS cells that highly expressed EZH2 and HO-1 infiltrated the tissues of experimental mice. IHC results indicated that these phenomena were related to the pRB-E2F pathway. High-throughput sequencing indicated that the progression of MDS to AML was related to EZH2. Using the E2F inhibitor HLM006474 and the EZH2 inhibitor JQEZ5, we showed that HO-1 could regulate EZH2 expression. HO-1 could stimulate the transcription and activation of EZH2 through the pRB-E2F pathway in MDS patients during chemotherapy, which reduced TP53 and P15INK4B expression. CONCLUSIONS: EZH2 was associated with HO-1 in high-risk and very high-risk MDS patients. HO-1 could influence MDS resistance and progression to AML.

5.
Chemosphere ; 242: 125200, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31683163

RESUMO

Cyclic methylsiloxanes (CMS) were listed as candidates of substances of very high concerns in 2018 by the REACH. These compounds can enter environmental waters, and potentially cause harmful effects to aquatic organisms and human beings. Until now, reaction mechanisms of these pollutants with hydroxyl radicals (HO) in aqueous phase were unknown. In this study, reaction mechanisms of three typical CMS (D4 ∼ D6) with HO in aqueous phase were investigated by employing both UV/H2O2 experiments and density functional theoretical calculations. Bimolecular reaction rate constants (kHO·) of D4 ∼ D6 with HO were determined as kHO·(D4) = 8kHO·(D5) = 12kHO·(D6) = 6.6 × 108 L mol-1 s-1. Half-lives of HO oxiding D4 ∼ D6 ranged from 12 to 140 days at [HO] = 10-15 mol L-1 in sunlit surface water, and were comparable to (D4, D5) or much shorter (D6) than hydrolytic half-lives. The reactivity to HO decreased with the increasing size of siloxane ring in aqueous phase, in an order totally opposite to that in gaseous phase. Calculation results indicated that HO oxidation of the three CMS proceeded spontaneously through an exothermic H-abstraction process at the first step. Water molecules participated into H-abstraction of CMS and caused energy barrier of D5 higher than that of D4. Thus, H-bonds formed by water molecules were responsible for the reverse reactivity of CMS in aqueous phase. This work provided basic evidences suggesting environmental persistence of CMS in aqueous phase completely different from that in gaseous phase.

6.
Zootaxa ; 4603(1): zootaxa.4603.1.5, 2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-31717241

RESUMO

In this study, two new brackish-water species of Macrostomum (M. shenda n. sp. and M. spiriger n. sp.) collected from Shenzhen, China, were described based on morphological, histological, and molecular phylogenetic analyses. Macrostomum shenda n. sp. differs from its congeners in the oblique and non-thickening distal opening of its narrow funnel-shaped stylet. In addition, its sperm have neither bristles nor brush, and are surrounded by an undulating membrane in the mid-body region. In M. spiriger n. sp., the stylet is spirally twisted. Its reproductive apparatus has a seminal bursal pore opening exteriorly. Results of the 18S and 28S rDNA phylogenetic analyses also support the establishments of these two new species. Moreover, the 18S and 28S rDNA sequences of some species within Macrostomum in previous studies have been revised to avoid ambiguity, while Macrostomum dongyuanensis Wang Sun, 2015 was re-identified as a new record of M. quiritium Kolasa, 1973 from China.


Assuntos
Platelmintos , Animais , China , DNA Ribossômico , Filogenia , Reprodução
7.
Artigo em Inglês | MEDLINE | ID: mdl-31591803

RESUMO

Nanogels have been identified as outstanding nanocarrier candidates for drug delivery due to the desirable physiochemical properties and versatile applicability for diverse therapeutic molecules and imaging probes. One of the main challenges that hinder the clinical translation of nanogels is the low efficiency of drug transmitting to the target sites because of the impedance of complex biological barriers during the in vivo journey. The purpose of this review is to summarize the recent advances on the rational design and structure modulation of nanogels to overcome the barriers and challenges on the way to the site of action following various dosing modes. In particular, the functional moieties or domains were incorporated in the nanogels, allowing them to spontaneously regulate their structure and physiochemical properties to cross one or some of the multifaceted barriers. Importantly, the perspectives are presented in case of opportunities and challenges for the precise and efficacious therapeutic of nanogel formulations.

8.
Sci Rep ; 9(1): 11958, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31420592

RESUMO

This contribution addresses an analytical model to predict the ignition time of PMMA (Polymethyl methacrylate) subjected to a time-decreasing incident heat flux. Surface temperature, transient mass flux and ignition time of PMMA are thoroughly studied based on the exact solutions of in-depth temperature. Critical mass flux is utilized as the ignition criteria. An approximation methodology is suggested to simplify the unsolvable high order equations and deduce the explicit expressions of ignition time. A numerical model is employed to validate the capability of the developed model. The results show that no ignition occurs when the decreasing rate of heat flux increases larger than a critical value. The agreement of the transient mass flux between analytical and numerical models is good at high decreasing rate but turns worse as the decreasing rate declines. However, this enhanced discrepancy affects the ignition time prediction slightly. The inverse of the square root of the ignition time is linearly correlated with the decreasing rate of heat flux, and it becomes significantly sensitive to the decreasing rate when the decreasing rate approaching its critical value. Meanwhile, the value of critical mass flux has appreciable influence on the ignition time prediction.

9.
Gigascience ; 8(8)2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31430367

RESUMO

BACKGROUND: Sitobion miscanthi is an ideal model for studying host plant specificity, parthenogenesis-based phenotypic plasticity, and interactions between insects and other species of various trophic levels, such as viruses, bacteria, plants, and natural enemies. However, the genome information for this species has not yet to be sequenced and published. Here, we analyzed the entire genome of a parthenogenetic female aphid colony using Pacific Biosciences long-read sequencing and Hi-C data to generate chromosome-length scaffolds and a highly contiguous genome assembly. RESULTS: The final draft genome assembly from 33.88 Gb of raw data was ∼397.90 Mb in size, with a 2.05 Mb contig N50. Nine chromosomes were further assembled based on Hi-C data to a 377.19 Mb final size with a 36.26 Mb scaffold N50. The identified repeat sequences accounted for 26.41% of the genome, and 16,006 protein-coding genes were annotated. According to the phylogenetic analysis, S. miscanthi is closely related to Acyrthosiphon pisum, with S. miscanthi diverging from their common ancestor ∼25.0-44.9 million years ago. CONCLUSIONS: We generated a high-quality draft of the S. miscanthi genome. This genome assembly should help promote research on the lifestyle and feeding specificity of aphids and their interactions with each other and species at other trophic levels. It can serve as a resource for accelerating genome-assisted improvements in insecticide-resistant management and environmentally safe aphid management.

10.
Magn Reson Imaging ; 63: 105-113, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31425797

RESUMO

PURPOSE: This study aimed to investigate whether amide proton transfer (APT) imaging, compared with intravoxel incoherent motion (IVIM) imaging-derived parameters, can differentiate squamous cell carcinoma of the cervix (SCCC) from the normal cervical stroma and distinguish poorly differentiated SCCC from well-moderately differentiated SCCC. METHODS: This prospective study enrolled 32 patients, comprising 20 patients with well-moderately differentiated SCCC and 12 patients with poorly differentiated SCCC. 20 healthy volunteers were enrolled as a control group. A bi-exponential model (BEM) analysis was performed to derive ADC, pure molecular diffusion coefficient (D), pseudo-diffusion coefficient (D*) and perfusion fraction (f). The APT signal intensity (APT SI), ADC, D, D* and f were measured. The parameters between the groups were compared with independent t-tests. Diagnostic performance was evaluated with a ROC analysis. RESULTS: The APT SI of SCCC (2.92 ±â€¯0.24%) was higher than that of normal cervical stroma (2.72 ±â€¯0.36%) with P = 0.020. The comparison of the AUCs for the diagnosis of SCCC was ADC > f > APT SI > D* > D. A significant difference was found in the APT SI between the well-moderately differentiated SCCC group (2.82 ±â€¯0.15%) and the poorly differentiated SCCC group (3.09 ±â€¯0.27%) with P = 0.006. Except for D (P = 0.012), the ADC, D* and f values were not significantly different between the groups (P > 0.05). The comparison of the AUCs for distinguishing poorly differentiated SCCC was APT SI > D > ADC > D* = f. CONCLUSION: APT imaging may be a useful technique in the diagnosis and predicting the differentiation of SCCC.

11.
ACS Appl Mater Interfaces ; 11(35): 31943-31953, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31407886

RESUMO

Improving the reversibility of conversion reaction is a promising way to enhance the lithium-ion storage capability of SnO2-based anodes. Herein, we report ferrocene as a novel additive to improve the Li-ion storage performance of the SnO2/graphene (SnO2/G) composite. Through a simple mixing method, ferrocene can be uniformly dispersed into the SnO2/G electrode. It is found that the ferrocene additive can effectively suppress the agglomeration of Sn/SnO2 and retain the nanoscale Sn/Li2O interface. Furthermore, metallic Fe is formed from ferrocene in the discharge process and acts as a catalyst to promote the reversible conversion between Sn/Li2O and SnO2. As a result, the SnO2/G electrode with the addition of 10 wt % ferrocene (10%Fc-SnO2/G) exhibits a superior Li-ion storage performance. It displays a reversible capacity of up to 1084.5 mAh g-1 at 0.1 A g-1 after 150 cycles with a good rate capability (752 mAh g-1 at 1 A g-1). In addition, the 10%Fc-SnO2/G electrode can retain a capacity of 787.2 mAh g-1 at 0.5 A g-1 after 220 cycles. This work demonstrates the promising additive of ferrocene in enhancing the reversible capacity of SnO2-based anodes for lithium-ion batteries.

12.
Magn Reson Imaging ; 63: 21-28, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31319128

RESUMO

PURPOSE: To explore changes in the amide proton transfer (APT) signal intensity (SI) among different phases of the menstrual cycle in healthy young women and to determine whether the APT SI correlates with the apparent diffusion coefficient (ADC). MATERIALS AND METHODS: Twenty healthy women of childbearing age received regular pelvic magnetic resonance imaging (MRI) examinations and APT scans during the menstrual, proliferative and secretory phases of their menstrual cycle. Then, the APT SI and ADC values of the endometrium, myometrium and junctional zone were measured and analyzed to explore the changes during different phases of the menstrual cycle. The Pearson correlation coefficients between the APT SI and ADC were calculated. RESULTS: Besides the APT SI in the secretory phase, the APT SI and ADC in each menstrual phase were higher in the myometrium and endometrium than in the junctional zone, the APT Si did not differ significantly between the endometrium and myometrium during any phase. In each uterine structure, both the SI and ADC were highest in the secretory phase, second highest in the proliferative phase and lowest in the menstrual phase, but the APT SI did not differ significantly between the menstrual phase proliferative phases. Interindividual variation in APT SI and ADC for a given zone or phase ranged from 1.86% to 2.75% and from 0.37 × 10-3 mm2/s to 0.85 × 10-3 mm2/s, respectively. The Pearson correlation coefficient between APT SI and ADC was 0.481 (P < 0.01). CONCLUSION: When the APT SI or ADC values are used to analyze uterine lesions, their changes during the menstrual cycle in childbearing aged women should be considered.

13.
J Clin Lab Anal ; 33(7): e22928, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31148296

RESUMO

BACKGROUND: Hepatitis C virus antibody (anti-HCV) test had been approved as a preliminary screening test for HCV infection. Light-initiated chemiluminescent assay (LiCA) was a homogenous method. We aimed to assess the clinical diagnostic performance of LiCA and compare it with that of chemiluminescence immunoassay (CLIA) which was widely used in clinical laboratories. METHODS: A total of 10 772 patients from the Peking University Third Hospital were enrolled. The serum samples were detected on the ChIVD LiCA500 and Abbott Architect i2000SR platforms. Recombinant immunoblot assay (RIBA) and HCV RNA assay were used for confirmation. RESULTS: The negative agreement rate between ChIVD LiCA anti-HCV assay and Abbott Architect anti-HCV assay was 99.91%, the positive agreement rate was 37.31%, the total agreement rate was 98.74%, and the kappa coefficient (κ) was 0.519. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of ChIVD LiCA anti-HCV assay were 96.39%, 99.95%, 89.58%, and 99.97%, respectively, which were superior to those of Abbott Architect anti-HCV assay (93.98%, 99.25%, 51.90%, and 99.95%, respectively). CONCLUSION: ChIVD LiCA anti-HCV assay was a highly sensitive, specific homogenous method with good diagnostic performance, and was applicable for the routine screening of HCV infection in clinical laboratories.

14.
Chemosphere ; 230: 616-627, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31128508

RESUMO

Understanding the transfer process of polycyclic aromatic hydrocarbons (PAHs) in the karst terrain is of great importance to their ecological risk assessments, however, the impact of the vertical transfer of the soil PAHs on the underground water is largely unknown in the karst system. Here, the vertical distribution and the seasonal variation of 16 PAHs in the soils and the water of 4 epikarst spring catchments in Southwest China were investigated. The total concentration of the PAHs ranged within 61-3285 ng g-1 in the soils, and 341-4969 ng L-1 in the spring water. The vertical distribution of the PAHs in soils varied with ring numbers and altitude of the catchment. PAHs concentrations were linearly related with the total organic carbon (TOC) at different depths in the catchments 563-783 m above the sea level (A.S.L.). However, no correlation with TOC was observed in the catchment of a high altitude (2090 m A.S.L.), because the large water flux led to the fast migration of the 2-3 rings PAHs in soils. The PAHs in soils and springs were mainly derived from the combustion of grass/wood/coal, closely related with the primary fossil fuels used in this area. This study demonstrate that the groundwater was heavily polluted by PAHs in the karst terrains of Southwest China, due to the vertical transfer of PAHs from the surface soils, and effective protection was urgently needed.


Assuntos
Monitoramento Ambiental/métodos , Água Subterrânea/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes do Solo/análise , Solo/química , Poluentes Químicos da Água/análise , China , Medição de Risco , Estações do Ano
15.
J Colloid Interface Sci ; 551: 155-163, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31078097

RESUMO

HYPOTHESIS: Modification of MIL-100(Fe) with ethanediamine (ED) is expected to improve the removal percentage of Pb(II) ions from aqueous solution. Nevertheless, the adsorption performance of ED-MIL-100(Fe) in natural waters will be affected by natural organic matter such as fulvic acids (FA). Hence, it is necessary to study the influence of FA on the physicochemical property, adsorption behavior and mechanisms of ED-MIL-100(Fe) towards the removal of Pb(II) from water. EXPERIMENTS: Batch adsorption experiments were conducted to compare adsorption capacity of MIL-100(Fe) and ED-MIL-100(Fe) for Pb(II). In addition, XRD, FTIR, SEM and XPS techniques were applied to investigate the characteristics, adsorption isotherms, and kinetics in the presence and absence of FA. FINDINGS: ED-MIL-100(Fe) enabled 99% removal of Pb(II) from water at or below 60 mg L-1, whereas the MIL-100(Fe) hardly adsorbed any Pb(II). Additionally, the adsorption percentage of the Pb(II) ions (76%) outcompeted that of other metal ions (i.e. Co, Cu, Ni, Zn, and Cd) (each ≤ 25%) in the mixed solution. The negative surface charge of ED-MIL-100(Fe) was not affected by FA. Increasing FA concentration steadily increased the functional groups surrounding the ED-MIL-100(Fe) via electrical interaction, thus facilitating the Pb(II) ions adsorption.

16.
Bioresour Technol ; 288: 121511, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31132594

RESUMO

In this work, a novel magnetic biochar of camphor leaf with large micropore area was prepared for ciprofloxacin removal. Biochar show the advantage of resource utilization, as an adsorbent in pollutant removal, but limited by its relatively low specific surface area and poor adsorption capacity. An efficient method was formulated to prepare ZnO nanoparticle modified magnetic biochar to adsorb ciprofloxacin. The biochar with ZnCl2/biochar mass ratio of 2 at the calcination temperature of 650 °C was a typical microporous material with huge surface area (915 m2 g-1). The maximum ciprofloxacin adsorption capacity of the biochar reached 449.40 mg L-1. The adsorption mechanism was discussed in terms of physical adsorption and chemisorption involving intense π-π stacking interaction, electrostatic interaction, cation exchange interaction etc. The adsorption capacity of biochar did not decline adsorption capacity significantly after 3 times regeneration. It provides a recycle and reuse way for camphor leaves resource disposal.


Assuntos
Poluentes Químicos da Água , Óxido de Zinco , Adsorção , Cânfora , Carvão Vegetal , Ciprofloxacino , Folhas de Planta
17.
Chem Commun (Camb) ; 55(39): 5659-5662, 2019 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-31032497

RESUMO

We report ionic self-assembly of two oppositely charged cobalt(iii) porphyrins (CoPs) on carbon coupled with subsequent mild pyrolysis at 350 °C, making CoPs lose some peripheral groups and become tightly adsorbed on the carbon with a high faradaic efficiency of 88 ± 1.5% and a current density of 8 mA cm-2 at a low overpotential of 430 mV toward electrochemical conversion of CO2 to CO.

18.
Artigo em Inglês | MEDLINE | ID: mdl-30954796

RESUMO

Characteristic variables are essential and necessary basis in model construction, and are related to the prediction result closely in near infrared spectroscopy (NIRS) analysis. However, the same compound usually has different characteristic variables for different analysis and it would be lower correlation between variables and structure in many researches. So, the accuracy and reliability are expected to improve by exploring characteristic variables in different spectrum analysis. In this study, competitive adaptive weighted resampling method (CARS) was applied to select characteristic variables related to baicalin from NIRS analysis data, which were applied to analysis of baicalin in three different processes including the herb, extraction process and concentration process of Scutellaria baicalensis. After application of CARS method, 70, 50 and 50 variables were selected respectively from three processes above. The selected variables were firstly analyzed by statistical methods that they were found to be consistent and correlated among three different processes after one-way analysis of variance test and Kendall's W. Partial least-squares (PLS) regression and extreme learning machine (ELM) models were constructed based on optimized data. Models after variable selection were less complicated and had better prediction results than global models. After comparison, CARS-PLS was suitable for the prediction of extraction process, while for the concentration process and herb, CARS-ELM performed better. The Rc value of the herb, extraction and concentration model were 0.9469, 0.9841 and 0.9675, respectively. The RSEP values were 4.54%, 6.96% and 8.37%, respectively. The results help to frame a theoretical basis for characteristic variables of baicalin.


Assuntos
Medicamentos de Ervas Chinesas/análise , Flavonoides/análise , Scutellaria baicalensis/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Algoritmos , Medicamentos de Ervas Chinesas/isolamento & purificação , Flavonoides/isolamento & purificação , Análise dos Mínimos Quadrados , Aprendizado de Máquina
19.
Genome ; 62(5): 329-339, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30933665

RESUMO

Fluorescence in situ hybridization (FISH) using oligonucleotides is a simple and convenient method for chromosome research. In this study, 34 of 46 previously developed oligonucleotides produced signals in barley. Together with two plasmid clones and one PCR-amplified cereal centromere repeat (CCS1) probe, 37 repetitive sequences were chromosomally located produced three types of signals covering different positions on the chromosomes. The centromeric and pericentric regions had a more complex genomic organization and sequence composition probably indicative of higher contents of heterochromatin. An efficient multi-plex probe containing eight oligonucleotides and a plasmid clone of 45S rDNA was developed. Thirty-three barley karyotypes were developed and compared. Among them, 11 irradiation-induced mutants of cultivar 08-49 showed no chromosomal variation, whereas 22 cultivar and landrace accessions contained 28 chromosomal polymorphisms. Chromosome 4H was the most variable and 6H was the least variable based on chromosome polymorphic information content (CPIC). Five polymorphic chromosomes (1H-2, 2H-1, 3H-3, 5H-2, and 6H-2) were dominant types, each occurring in more than 50% of accessions. The multi-plex probe should facilitate identification of further chromosomal polymorphisms in barley.


Assuntos
Cromossomos de Plantas/genética , Hordeum/genética , Polimorfismo Genético/genética , Sequências Repetitivas de Ácido Nucleico/genética , Centrômero/genética , Sondas de DNA/genética , Hibridização in Situ Fluorescente , Cariótipo , Cariotipagem , Oligonucleotídeos/genética , RNA de Plantas/genética , RNA Ribossômico/genética
20.
Small ; 15(6): e1804152, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30645019

RESUMO

The low-dimensional halide perovskites have received enormous attention due to their unique photovoltaic and optoelectronic performances. Periodic spacers are used to inhibit the growth of 3D perovskite and fabricate a 2D counterpart with layered structure, mostly based on organic/inorganic cations. Herein, by introducing organic anions (e.g., pentanedioic acid (PDA) and hexanedioic acid (HDA) simultaneously), leaf-shaped (Cs3 Pb2 Br5 )2 (PDA-HDA) microplates with low-dimensional structure are synthesized. They also exhibit significant photoluminescence (PL) centered at 540 nm with a narrow emission peak. The synthesis of single crystals of Pb(PDA) and Pb(HDA) allows to further clarify the crystal structure of (Cs3 Pb2 Br5 )2 (PDA-HDA) perovskite and its structural evolution mechanism. Moreover, the cooperative introduction of dicarboxylic acid pairs with appropriate lengths is thermodynamically favored for the low-dimensional perovskite crystallization. The temperature-dependent PL indicates a V-shaped Stokes shift with elevated temperature that could be associated with the localization of excitons in the inorganic layers between organic dicarboxylic acid molecules. This work demonstrates low-dimensional halide perovskite with anionic spacers, which also opens up a new approach to the growth of low-dimensional organic-inorganic hybrid perovskite crystals.

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