Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.875
Filtrar
1.
Chaos ; 29(8): 083112, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31472492

RESUMO

We study numerically the evolutions of perturbations at critical points between modulational instability and stability regimes. It is demonstrated that W-shaped solitons and rogue waves can be both excited from weak resonant perturbations at the critical points. The rogue wave excitation at the critical points indicates that rogue wave comes from modulation instability with resonant perturbations, even when the baseband modulational instability is absent. The perturbation differences for generating W-shaped solitons and rogue waves are discussed in detail. These results can be used to generate W-shaped solitons and rogue waves controllably from weak perturbations.

2.
Cell Rep ; 28(10): 2689-2703.e4, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31484078

RESUMO

Cooperative binding of transcription factors (TFs) to chromatin orchestrates gene expression programming and cell fate specification. However, the biophysical principles of TF cooperativity remain incompletely understood. Here we use single-molecule fluorescence microscopy to study the partnership between Sox2 and Oct4, two core members of the pluripotency gene regulatory network. We find that the ability of Sox2 to target DNA inside nucleosomes is strongly affected by the translational and rotational positioning of its binding motif. In contrast, Oct4 can access nucleosomal sites with equal capacities. Furthermore, the Sox2-Oct4 pair displays nonreciprocal cooperativity, with Oct4 modulating interaction of Sox2 with the nucleosome but not vice versa. Such cooperativity is conditional upon the composite motif's residing at specific nucleosomal locations. These results reveal that pioneer factors possess distinct chromatin-binding properties and suggest that the same set of TFs can differentially regulate gene activities on the basis of their motif positions in the nucleosomal context.

3.
Biomolecules ; 9(9)2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31480620

RESUMO

The dominance of safener can unite with herbicides acquiring the efficient protection of crop and qualifying control of weeds in agricultural fields. In order to solve the crop toxicity problem and exploit the novel potential safener for fenoxaprop-P-ethyl herbicide, a series of trichloromethyl dichlorobenzene triazole derivatives were designed and synthesized by the principle of active subunit combination. A total of 21 novel substituted trichloromethyl dichlorobenzene triazole compounds were synthesized by substituted aminophenol and amino alcohol derivatives as the starting materials, using cyclization and acylation. All the compounds were unambiguously characterized by IR, 1H-NMR, 13C-NMR, and HRMS. A greenhouse bioassay indicated that most of the title compounds could protect wheat from injury caused by fenoxaprop-P-ethyl at varying degrees, in which compound 5o exhibited excellent safener activity at a concentration of 10 µmol/L and was superior to the commercialized compound fenchlorazole. A structure-activity relationship for the novel compounds was determined, which demonstrated that those compounds containing benzoxazine groups showed better activity than that of oxazole-substituted compounds. Introducing a benzoxazine fragment and electron-donating group to specific positions could improve or maintain the safener activity for wheat against attack by the herbicide fenoxaprop-P-ethyl. A molecular docking model suggested that a potential mechanism between 5o and fenoxaprop-P-ethyl is associated with the detoxication of the herbicide. Results from the present work revealed that compound 5o exhibited good crop safener activities toward wheat and could be a promising candidate structure for further research on wheat protection.

4.
Obes Rev ; 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31482658

RESUMO

Childhood obesity is one of the most pressing public health issues nowadays. The environmental factors have been identified as potential risks for obesity, as they may influence people's lifestyle behaviours. Lack of access to supermarkets that usually provide healthy food options has been found to be a risk factor for childhood obesity in several studies. However, findings remained inconclusive. We aimed to systematically review the association between access to supermarkets and childhood obesity. A literature search was conducted in the Cochrane Library, PubMed, Web of Science, and Embase for studies published before 1 January 2019. Twenty-four studies conducted in four countries were identified, from which data on the basic characteristics of studies and participants, measures of access to supermarkets, and associations between access to supermarkets and weight-related behaviours and outcomes were extracted. The median sample size was 1858 participants. Half of the included studies indicated a negative association, one fourth reported a positive association, and the remaining one fourth did not find a significant association. Better designed studies are necessary to achieve a robust understanding of this epidemiological relationship in the future.

5.
Int J Biol Macromol ; 141: 41-50, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31476391

RESUMO

In this study, the reaction conditions of sulfur trioxide-pyridine (SO3-Pyr) method for the modification of Qingke ß-glucans (THB) were optimized by response surface methodology, and effects of different degrees of substitution (low, medium, and high) on the physicochemical properties, antioxidant activities, and in vitro hypolipidemic activities of THB were investigated. The optimal reaction conditions to obtain the high degree of substitution of sulfated ß-glucans were as follows: ratio of SO3-Pyr to THB of 16.88 g/g, reaction time of 2.03 h, and reaction temperature of 57.54 °C. Results showed that sulfated modification significantly affected the water solubilities, apparent viscosities, molecular weights, and molar ratios of constituent monosaccharides of THB. Besides, the sulfated THB exhibited much better antioxidant activities (DPPH and nitric oxide radical scavenging activities, and reducing powers), in vitro binding properties (fat, cholesterol, and bile-acid binding capacities), and pancreatic lipase inhibition activities than that of THB. Indeed, the sulfated THB with higher degree of substitution has stronger antioxidant activities and in vitro hypolipidemic activities. Results suggested that the sulfated modification could be an efficient approach for the improvement of functional properties of THB, and sulfated THB could be further explored as functional food ingredients for industrial applications.

6.
J Hematol Oncol ; 12(1): 91, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31488218

RESUMO

BACKGROUND: Long non-coding RNAs (lncRNAs) have been associated with non-small cell lung cancer (NSCLC), but the underlying molecular mechanisms of their specific roles in mediating aerobic glycolysis have been poorly explored. METHODS: Next-generation RNA sequencing assay was performed to identify the differentially expressed RNAs between NSCLC tissues with high 18F-fluorodeoxyglucose (FDG) uptake and their adjacent normal lung tissues. LINC01123 expression in NSCLC tissues was measured by real-time PCR and in situ hybridization (ISH) assay. The biological role of LINC01123 in cell growth and aerobic glycolysis capability was determined by performing functional experiments in vitro and in vivo. Further, the transcription of LINC01123 was explored by bioinformatics analysis, dual-luciferase reporter assay, and chromatin immunoprecipitation (ChIP) assay. RNA immunoprecipitation (RIP) and luciferase analyses were used to confirm the predicted competitive endogenous RNA (ceRNA) mechanisms between LINC01123 and c-Myc. RESULTS: Three hundred sixty-four differentially expressed genes were identified in RNA-seq assay, and LINC01123 was one of the most overexpressed lncRNAs. Further validation in expanded NSCLC cohorts confirmed that LINC01123 was upregulated in 92 paired NSCLC tissues and associated with poor survival. Functional assays showed that LINC01123 promoted NSCLC cell proliferation and aerobic glycolysis. Mechanistic investigations revealed that LINC01123 was a direct transcriptional target of c-Myc. Meanwhile, LINC01123 increased c-Myc mRNA expression by sponging miR-199a-5p. In addition, rescue experiments showed that LINC01123 functioned as an oncogene depending on miR-199a-5p and c-Myc. CONCLUSION: Since LINC01123 is upregulated in NSCLC, correlates with prognosis, and controls proliferation and aerobic glycolysis by a positive feedback loop with c-Myc, it is expected to be a potential biomarker and therapeutic target for NSCLC.

7.
J Colloid Interface Sci ; 556: 640-649, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31494394

RESUMO

High sensitivity and selectivity detection of NO at room temperature has always been full of challenges. In this work, a kind of porous ZnO with coralline-like nanostructure was prepared by a rapid and simple solid-state synthesis strategy, using zinc acetate and oxalic acid as precursors. Structural analysis and morphological investigations of the ZnO powder showed that it has a large specific surface area (32.75 m2 g-1) and many nanometer-sized channels between ZnO nanoparticles. This is beneficial to the adsorption and desorption of NO, which is an important reason for the selective detection of NO by the ZnO powder at room temperature. So based on the ZnO powder, a gas sensor was fabricated and its gas-sensing properties were investigated. It exhibited outstanding response (23.59) and fast response time (331 s) to 40 ppm of NO at room temperature (21 ±â€¯2 °C). As the relative humidity study changed from 17% to 80% at 10 ppm of NO, the sensitivity of the sensor changed little, only decreased from 1.43 to 1.12. The stability study was also carried out. Under the concentration of 5 ppm of NO, the relative standard deviation was 0.33% within 8 days, which indicates that the obtained sensor is suitable for practical application.

8.
J Agric Food Chem ; 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31509401

RESUMO

Three new phenazine metabolites strepphenazine A-C (1-3), along with a known compound baraphenazine E 4 were isolated from the culture broth of a Streptomyces strain YIM PH20095. The structures were elucidated based on the spectral data. Compounds 1-4 showed different antifungal activity against Fusarium oxysporum, Plectosphaerella cucumerina, Alternaria panax, and Phoma herbarum, which caused root-rot disease of Panax notoginseng with minimal inhibitory concentrations (MICs) of 16-64 µg/mL, compared with compound 4, compounds 1-3 showed better antifungal activity against some of these pathogenic fungi with MICs of 16-32 µg/mL, while compound 4 showed antifungal activity against F. oxysporum, P. cucumerina, and A. panax and with the same MICs of 64 µg/mL. Thus, strain YIM PH20095 provides new sources for the development of biological control agents to prevent the infection of pathogenic fungi of P. notoginseng. KEYWORDS: phenazine metabolites, Streptomyces species, antifungal activity, structure characterization.

9.
J Exp Clin Cancer Res ; 38(1): 401, 2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31511060

RESUMO

BACKGROUND: Colon cancer is the second leading cancer worldwide. Recurrent disease and chemotherapeutic drug resistance are very common in the advanced stage of colon cancer. ATP-citrate lyase (ACLY), the first-step rate-controlling enzyme in lipid synthesis, is elevated in colon cancer. However, it remains unclear about the exact role of ACLY in the development of colon cancer metastasis. METHODS: To evaluate the role of ACLY in colon cancer metastasis, we performed cell migration and invasion assays in two ACLY-deficient colon cancer cell lines. Colon cancer mouse model is used to examine ACLY's effects on colon metastasis potentials in vivo. We analyzed the correlation between ACLY and CTNNB1 protein in 78 colon cancer patients by Pearson correlation. To finally explore the relationship of ACLY and CTNNB1, we used western blots, migration and invasion assays to confirm that ACLY may regulate metastasis by CTNNB1. RESULTS: Our data showed that the abilities of cell migration and invasion were attenuated in ACLY-deficient HCT116 and RKO cell lines. Furthermore, we describe the mechanism of ACLY in promoting colon cancer metastasis in vitro and in vivo. ACLY could stabilize CTNNB1 (beta-catenin 1) protein by interacting, and the complex might promote CTNNB1 translocation through cytoplasm to nucleus, subsequently promote the CTNNB1 transcriptional activity and migration and invasion abilities of colon cancer cells. Immunohistochemical analysis of 78 colon cancer patients showed that the high expression levels of ACLY and CTNNB1 protein was positively correlated with metastasis of colon cancer. CONCLUSIONS: These results shed new light on the molecular mechanism underlying colon cancer metastasis, which might help in improving therapeutic efficacy.

10.
Artigo em Inglês | MEDLINE | ID: mdl-31512996

RESUMO

BACKGROUND: Forkhead box C1 (FOXC1) is an important cancer associated gene in tumor. PPAR-γ and C/EBPα are both transcriptional regulators involved in tumor development. OBJECTIVE: We aimed to clarify the function of PPAR-γ, C/EBPα in hepatocellular carcinoma (HCC) and relationship of PPAR-γ, C/EBPα and FOXC1 in HCC. METHOD: Western blotting, immunofluorescent staining and immunohistochemistry were used to evaluate protein expression. qRT-PCR was used to assess mRNA expression. Co-IP was performed to detect the protein interaction. And ChIP and fluorescent reporter detection were used to determine the binding between protein and FOXC1 promoter. RESULTS: C/EBPα could bind to FOXC1 promoter and PPAR-γ could strengthen C/EBPα's function. Expressions of C/EBPα and PPAR-γ were both negatively related with FOXC1 in human HCC tissue. Confocal displayed that C/EBPα was co-located with FOXC1 in HepG2 cells. C/EBPα could bind to FOXC1 promoter by ChIP. Luciferase activity detection exhibited that C/EBPα could inhibit FOXC1 promoter activity, especially FOXC1 promoter from -600 to -300 was the critical binding site. Only PPAR-γ couldn't influence luciferase activity but strengthen inhibited effect of C/EBPα. Further, the Co-IP displayed that PPAR-γ could bind to C/EBPα. When C/EBPα and PPAR-γ was both high expressed, cell proliferation, migration, invasion and colony information were inhibited enormously. C/EBPα plasmid combined with or without PPAR-γ agonist MDG548 treatment exhibited a strong tumor inhibition and FOXC1 suppression in mice. CONCLUSION: Our data establish C/EBPα targeting FOXC1 as potential determinant in the HCC, which supplies a new pathway to treat HCC. However, PPAR-γ has no effect on FOXC1 expression.

11.
J Exp Child Psychol ; 188: 104679, 2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31499456

RESUMO

Although there has been extensive research on how children distribute resources with respect to quantity, little is known about how these decisions are affected by resource quality. The current research addressed this question by conducting two preregistered studies in which 3-, 5-, and 7-year-old children (total N = 360) made anonymous distributions of high-quality and low-quality items. Quantitative fairness entailed distributing an equal number of items irrespective of quality, and qualitative fairness entailed distributing equal numbers of high-quality and low-quality items. In Study 1, a majority of 7-year-olds distributed resources equally between themselves and another child in terms of both quality and quantity, whereas a majority of 3- and 5-year-olds did so only in terms of quantity while giving themselves a qualitative advantage. In Study 2, a majority of children in all three age groups distributed resources equally between two other children in terms of both quality and quantity. Together with prior findings, these results suggest that children selectively ignore the dimension of quality when it serves their own interests. The results also show, for the first time, that by 7 years of age children consider quality even at the expense of their own interests and that children as young as 3 years have the capacity to take into account resource quality when making distributions.

13.
Molecules ; 24(17)2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31443550

RESUMO

Herbicide safeners selectively protect crops from herbicide injury while maintaining the herbicidal effect on the target weed. To some extent, the detoxification of herbicides is related to the effect of herbicide safeners on the level and activity of herbicide target enzymes. In this work, the expression of the detoxifying enzyme glutathione S-transferase (GST) and antioxidant enzyme activities in maize seedlings were studied in the presence of three potential herbicide safeners: 3-dichloroacetyl oxazolidine and its two optical isomers. Further, the protective effect of chiral herbicide safeners on detoxifying chlorsulfuron in maize was evaluated. All safeners increased the expression levels of herbicide detoxifying enzymes, including GST, catalase (CAT), and peroxidase (POD) to reduce sulfonylurea herbicide phytotoxicity in maize seedlings. Our results indicate that the R-isomer of 3-(dichloroacetyl)-2,2,5-trimethyl-1,3-oxazolidine can induce glutathione (GSH) production, GST activity, and the ability of GST to react with the substrate 1-chloro-2,4-dinitrobenzene (CDNB) in maize, meaning that the R-isomer can protect maize from damage by chlorsulfuron. Information about antioxidative enzyme activity was obtained to determine the role of chiral safeners in overcoming the oxidative stress in maize attributed to herbicides. The interaction of safeners and active target sites of acetolactate synthase (ALS) was demonstrated by molecular docking modeling, which indicated that both isomers could form a good interaction with ALS. Our findings suggest that the detoxification mechanism of chiral safeners might involve the induction of the activity of herbicide detoxifying enzymes as well as the completion of the target active site between the safener and chlorsulfuron.

15.
Lancet Glob Health ; 7(9): e1166-e1167, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31401995
16.
Int J Biol Macromol ; 139: 459-467, 2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31381911

RESUMO

In order to well understand the physicochemical characteristics and biological activities of polysaccharides (OPPs) from different cultivars of okra collected in China, the chemical characteristics, rheological properties, antioxidant activities, in vitro binding properties, and in vitro inhibitory effects on α-glucosidase of polysaccharides from five representative okra cultivars, including 'Lvjian', 'Kalong8', 'Shuiguo', 'Taiwanwufu', and 'Kalong3', were investigated and compared. Results showed that the constituent monosaccharides of OPPs were similar, which composed of rhamnose, galacturonic acid, galactose, and arabinose. However, their weight-average molecular weights varied from 2.76 × 103 to 4.20 × 103 kDa, and from 0.11 × 103 to 0.90 × 103 kDa, respectively. The uronic acids and degrees of esterification of OPPs ranged from 39.32% to 61.68%, and from 21.66% to 30.02%, respectively. OPPs exhibited typical shear-thinning behavior and viscoelastic properties. Furthermore, OPPs exhibited remarkable antioxidant activities, in vitro binding capacities, and inhibitory effects on α-glucosidase, which might be attributed to their relatively high content of uronic acids, high degrees of esterification, and high molecular weights. Results are helpful for better understanding of the physicochemical structures and bioactivities of OPPs, and OPPs had good application prospects as functional food ingredients for industrial applications.

17.
Exp Lung Res ; : 1-9, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31452411

RESUMO

Aim: Acute lung injury (ALI), a critical illness syndrome with high morbidity and mortality, is characterized by a severe inflammatory response. Dioscin exerts protective effects against crystalline silica-induced pulmonary inflammation and fibrosis in mice. Bleomycin (BLM) is widely used to induce ALI and fibrosis in animal models. This study aims to investigate the effects of dioscin on BLM-induced ALI in mice. Methods: C57BL/6 mice were intratracheally injected with BLM to induce ALI. Lungs and bronchoalveolar lavage fluids were then harvested on day 7 for evaluation. Changes in tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1ß), and interleukin-10 (IL-10) expression level were measured by RT-qPCR and ELISA. Protein expressions of nuclear factor-kappa B (NF-κB), cyclooxygenase-2 (COX-2), and high-mobility group box 1 (HMGB1) were measured by western blot. Results: Dioscin protects against BLM-induced ALI by decreasing the numbers of total and inflammatory cells, lung edema, myeloperoxidase activity, and malondialdehyde content. Moreover, dioscin significantly inhibited TNF-α, IL-1ß, NF-κB, COX-2, and HMGB1 levels, and upregulated IL-10 levels. Conclusion: Our data indicate that dioscin attenuates oxidative stress, the lung inflammatory response, and acute lung injury in BLM-challenged mice.

18.
Menopause ; 26(9): 1010-1015, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31453963

RESUMO

OBJECTIVE: We aimed to investigate whether the number of pregnancies during childbearing age was associated with diabetes in postmenopausal women with no history of gestational diabetes. METHODS: Our data source was the continuous National Health and Nutrition Examination Survey 1999 to 2014. We selected 9,138 postmenopausal women over 40 years old who did not have a history of gestational diabetes during pregnancy. Logistic regression analyses were applied for the association of the number of pregnancies with diabetes. RESULTS: We found women with ≥4 pregnancies had significantly greater fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), 2-hour plasma glucose, and the Homeostatic Model Assessment of Insulin Resistance than those with two to three pregnancies (all P < 0.01). These women also had a significantly higher prevalence of diabetes (28.4% vs 20.7%; P < 0.001). Using the two to three pregnancies group as the reference, we observed a positive association of log-FPG and log-HbA1c with 4 or more pregnancies after adjustment for sociodemographic, lifestyle, and reproductive factors, and body mass index (both P < 0.05). Compared to women with two to three pregnancies, the odds ratios for diabetes were 1.31 (95% confidence interval [CI] 1.01-1.71) for women who never got pregnant and 1.28 (95% CI 1.10-1.48) for those with at least 4 pregnancies after multivariate adjustment. CONCLUSIONS: At least 4 pregnancies through childbearing age may be a potential risk factor for diabetes in postmenopausal women without a history of gestational diabetes.

19.
Medicine (Baltimore) ; 98(35): e17002, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31464955

RESUMO

BACKGROUND: Chinese herbal medicine (CHM) has been shown to be effective in the treatment of stable chronic obstructive pulmonary disease (COPD) by published meta-analyses. However, disease outcomes were inconsistent and heterogeneity was observed attributed to placebo-controlled studies. We present a protocol for a systematic review aiming to evaluate the clinical efficacy and safety of CHM comparing to placebo in the treatment of stable COPD, to provide robust evidence for the use of CHM in COPD. METHODS: We will comprehensively search the following 9 databases from inception to March 2019: Web of Science, PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), Chinese National Knowledge Infrastructure (CNKI), WANFANG Database, Chinese Scientific and Technological Periodical Database (VIP) and Chinese Biomedical Database (CBM), and the Cochrane Library database. All clinical randomized controlled trials comparing CHM to placebo for the treatment of stable COPD in English or Chinese will be included. The primary outcome will be quality of life, symptom score and exacerbation frequency, and the secondary outcomes include traditional Chinese medicine syndrome score and effective rate, lung function, 6-minute walk distance, and adverse events. Data extraction and quality assessment will be performed independently by 2 reviewers. Data synthesis and risk of bias will be assessed using the Review Manager software. This protocol will be conducted according to the Preferred Reporting Item for Systematic Review and Meta-analysis Protocols (PRISMA-P) guidance. RESULTS: This systematic review and meta-analysis will provide a high-quality comprehensive evaluation of the efficacy and safety based on current literature evidence of CHM intervention for stable COPD. CONCLUSION: The conclusion of this study will present the evidence of whether CHM is an effective and safe intervention for stable COPD patients.

20.
Elife ; 82019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31418408

RESUMO

The testis is a peculiar tissue in many respects. It shows patterns of rapid gene evolution and provides a hotspot for the origination of genetic novelties such as de novo genes, duplications and mutations. To investigate the expression patterns of genetic novelties across cell types, we performed single-cell RNA-sequencing of adult Drosophila testis. We found that new genes were expressed in various cell types, the patterns of which may be influenced by their mode of origination. In particular, lineage-specific de novo genes are commonly expressed in early spermatocytes, while young duplicated genes are often bimodally expressed. Analysis of germline substitutions suggests that spermatogenesis is a highly reparative process, with the mutational load of germ cells decreasing as spermatogenesis progresses. By elucidating the distribution of genetic novelties across spermatogenesis, this study provides a deeper understanding of how the testis maintains its core reproductive function while being a hotbed of evolutionary innovation.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA