Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 366
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Microbiologyopen ; : e937, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31560838

RESUMO

Streptococcus mutans and Candida albicans are often isolated from plaques associated with early childhood caries. However, there are limited studies examining how these microorganisms interact with one another and how best to manage them. Recent studies have shown that curcumin (CUR), a natural compound, has the potential to independently control both of these microorganisms. The purpose of this study was to investigate how S. mutans and C. albicans respond in mono- and dual-species biofilms challenged with CUR. Quantitative biofilm biomass and viability were first evaluated and supported by live-dead PCR to assess biofilm composition. Confocal laser scanning microscopy (CLSM) was used to evaluate the exopolysaccharide (EPS) content and thickness of the biofilms, and the structure of the biofilms and morphology of the cells were observed by scanning electron microscopy (SEM). Quantitative real-time PCR (qRT-PCR) was applied to assess relative gene expression. The 50% minimum biofilm eradication concentration (MBEC50 ) of CUR against S. mutans and C. albicans was 0.5 mM. The biomass and viability decreased after treatment with CUR both in dual-species biofilms and in mono-species biofilm. CUR inhibited S. mutans and C. albicans in both mono- and dual-species biofilms. Streptococcus mutans was more sensitive to CUR in dual-species biofilm than in mono-species biofilms, whereas C. albicans was less sensitive in dual-species biofilms. EPS production was decreased by CUR in both mono- and dual-species biofilms, which coincided with the downregulation of glucosyltransferase and quorum sensing-related gene expression of S. mutans. In C. albicans, the agglutinin-like sequence family of C. albicans was also downregulated in dual-species biofilms. Collectively, these data show the potential benefit of using a natural antimicrobial, CUR, to control caries-related dual-species plaque biofilms.

2.
Drug Des Devel Ther ; 13: 2689-2702, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31496648

RESUMO

Objective: Retinitis pigmentosa causes progressive photoreceptor degeneration in the subjects while no clinical therapy exists. The present study sought to evaluate the potential protective effects of taurine on a pharmacologically induced RP animal model. Methods: Photoreceptor degeneration in mice was induced by an intraperitoneal injection of N-methyl-N-nitrosourea (MNU). The MNU-administrated mouse received taurine treatment and then they were examined by electroretinography, spectral-domain optical coherence tomography, optokinetic test, and histological and immunohistochemistry assay. Results: Prominent taurine deficiency was found in the retinas of MNU-administered mice. Intravenous taurine treatment increased significantly the retinal taurine level. Morphological studies showed that taurine could alleviate the retinal disorganizations in the MNU-induced mice. Taurine also ameliorated the visual impairments in the MNU-induced mice as evidenced by functional examinations. Immunostaining experiments demonstrated that both the M-cone and S-cone populations in the degenerative retinas are rescued by taurine. In particular, the M-cone photoreceptors in superior-temporal quadrant and the S-cone photoreceptors in inferior-nasal quadrant were preferentially rescued. Mechanism study showed that the photoreceptor apoptosis and oxidative stress in the degenerative retina were effectively alleviated by taurine treatment. Conclusion: Taurine is protective against the MNU-induced photoreceptor degeneration. Systemic taurine administration may act as a promising therapeutic potion for retinopathies with chronic cycle.

3.
Mycopathologia ; 2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31538279

RESUMO

Trichophyton rubrum (T. rubrum) is anthropophilic fungus and thus a very common cause of dermatophyte infections around the world. Infection of T. rubrum could result in conditions such as tinea capitis, tinea corporis, tinea inguinalis, tinea manus, tinea unguium, or tinea pedis. Because of this, the resistance of T. rubrum to antifungal therapies has drawn extensive research interest. However, the pathogenic characteristics of T. rubrum, such as site of infections, geographic location and host groups, have yet to be explored. In this study, the whole genome of 48 strains from different regions is resequenced and the population structure and association of single nucleotide polymorphism with resistance to six widely used antifungal drugs are analyzed. A total of 23,394 genomic variations are detected, which cover 2165 genes with only 15.14% of the variations located in exons. The population structure of T. rubrum is monomorphic, and genetic diversity is very low. Population structure analysis shows that the 48 sampled strains can be divided into two sub-populations. The gene TERG_08771 harboring the highest SNPs density is found to be associated with resistance to voriconazole. Although many proteins have yet to be identified and explored, association studies could still be useful to identify drug resistance or drug-susceptible loci, which would warrant further insightful investigations.

4.
Genomics ; 2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31401233

RESUMO

Lineage-specific genes (LSGs) are a set of genes in a given taxon without significant sequence similarity to genes and intergenic sequences of other taxa and are functional. The tribe Triticeae mainly includes species of different ploidy levels, such as staple food crops wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). This study is aimed at mining and characterizing the Triticeae-specific genes (TSGs) using expressed sequence data of wheat. A total of 3812 TSGs was identified and they were generally characterized by smaller size, fewer exons, shorter open reading frames and lower expression levels. Most TSGs were expressed with tissue preference and many of them were predominantly expressed in reproduction related tissues, especially in young stamen. Nearly one third of the TSGs were stress-responsive and inducible under abiotic and/or biotic stresses. A co-expression-based annotation supported the relevance of some TSGs with reproduction and stress responses, indicating their potential economic importance.

5.
Lab Chip ; 19(17): 2936-2946, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31380864

RESUMO

It is becoming more difficult to use bulk mixing and bi-fluid micromixing in multi-step continuous-flow reactions, multicomponent reactions, and nanoparticle synthesis because they typically involve multiple reactants. To date, most micromixing studies, both passive and active, have focused on how to efficiently mix two fluids, while micromixing of three or more fluids together (multi-fluid mixing) has been rarely explored. This study is the first on tri-fluid mixing in microchannels. We investigated tri-fluid mixing in three microchannel models: a straight channel, a classical staggered herringbone mixing (SHM) channel, and a three-dimensional (3D) X-crossing microchannel. Numerical simulations and experiments were jointly conducted. A two-step experimental process was performed to determine the tri-fluid mixing efficiencies of these microchannels. We found that the SHM cannot significantly enhance mixing of three streams especially for a Reynolds number (Re) higher than 10. However, the 3D X-crossing channel based on splitting-and-recombination (SAR) showed effective tri-mixing performance over a wide Re range up to 275 (with a corresponding flow rate of 1972.5 µL min-1), thereby enabling high microchannel throughput. Furthermore, this tri-fluid micromixing process was used to synthesize a kind of Si-based nanoparticle. This achieved a narrower particle size distribution than traditional bulk mixing. Therefore, SAR-based tri-fluid mixing is an alternative for chemical and biochemical reactions where three reactants need to be mixed.

6.
Biomed Pharmacother ; 117: 109021, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31387173

RESUMO

Inherited retinal degeneration (RD) comprises a heterogeneous group of retinopathies that rank among the main causes of blindness. Tauroursodeoxycholic acid (TUDCA) is taurine conjugate hydrophilic bile acid that demonstrates profound protective effects against a series of neurodegenerative diseases related to oxidative stress. This study sought to evaluate the TUDCA induced effects of on a pharmacologically induced RD animal model by electroretinogram (ERG) examination, behavior tests, morphological analysis and immunochemistry assay. Massive photoreceptor degeneration in mice retina was induced by an intraperitoneal administration of N-methyl-N-nitrosourea(MNU). Subcutaneous delivery of TUDCA inhibits effectively the photoreceptor loss and visual impairments in the MNU administered mice. In the retinal flat-mounts of TUDCA treated mice, the cone photoreceptors were efficiently preserved. Furthermore, the multi-electrodes array (MEA) was used to detect the firing activities of retinal ganglion cells within the inner retinal circuits. TUDCA therapy could restrain the spontaneous firing response, enhance the light induced firing response, and preserve the basic configurations of ON-OFF signal pathway in degenerative retinas. Our MEA assay provided an example to evaluate the potency of pharmacological compounds on retinal plasticity. TUDCA affords these protective effects by modulating apoptosis and alleviating oxidative stress in the degenerative retina. In conclusion, TUDCA therapy can ameliorate the photoreceptor degeneration and rectify the abnormities in visual signal transmission. These findings suggest that TUDCA might act as a potential medication for these retinopathies with progressive photoreceptor degeneration.

7.
Curr Microbiol ; 76(11): 1238-1246, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31377819

RESUMO

Streptococcus mutans (S. mutans) adheres to the tooth surface, metabolizes carbohydrates, and produces acid products, leading to enamel demineralization-the onset of dental caries. Rapid acidification by S. mutans has been observed in the presence of glucose. However, little is known about the role of small RNAs (sRNAs) in S. mutans in the presence of glucose and their relationship to tooth adherence. The objective of this study was to evaluate the role of sRNAs in S. mutans (18-50 nucleotides) regarding adherence capacity under 1% and 5% glucose concentrations. The pH drop and adherence capacity in the 1% glucose condition were similar to these parameters under conditions of 5% sucrose that were published in our previous study. A total of 2149 candidate sRNA with at least 100 average reads in the 5% and 1% glucose libraries were obtained. Between the two libraries, 581 sRNAs were differentially expressed and 43 sRNAs were verified. However, the expression levels of the predicted target genes gtfC and spaP were similar between the 1% and 5% glucose conditions. The bioinformatic analysis suggested that differentially expressed sRNAs may be involved in several pathways. These findings indicate that sRNAs were induced under these glucose concentrations and a series of sRNAs were specifically induced, respectively. sRNAs that are induced under glucose stress may be involved in regulating adherence of S. mutans.

8.
Int J Mol Med ; 44(4): 1219-1232, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31364725

RESUMO

The present study aimed to investigate the roles of the microRNA­29a/DNA methyltransferase 3B/suppressor of cytokine signalling 1 (miR­29a/DNMT3B/SOCS1) axis in the invasion and the migration of osteosarcoma (OS). The expression levels of miR­29a, DNMT3B and SOCS1 were determined in tissue samples and OS cell lines by reverse transcription­quantitative polymerase chain reaction (PCR). Apoptosis was measured using flow cytometry analysis. Transwell and wound healing assays were conducted to measure the invasion and migration abilities of OS cells, respectively. A dual­luciferase reporter assay was also conducted to determine the interaction between DNMT3B and miR­29a, while methylation­specific PCR was used to detect the methylation of SOCS1. Western blotting was performed to determine the protein levels of DNMT3B and SOCS1, as well as the levels of proteins associated with epithelial­mesenchymal transition (EMT), apoptosis and the nuclear factor (NF)­κB signalling pathway. The results demonstrated that miR­29a and SOCS1 were downregulated, and DNMT3B was upregulated in both OS tissues and cell lines. The expression of miR­29a and SOCS1 was found to be associated with advanced clinical stage and distant metastasis. In addition, the dual­luciferase reporter assay revealed that DNMT3B was a direct target of miR­29a. Overexpression using miR­29a mimics decreased DNMT3B expression and the methylation level of SOCS1, which resulted in the upregulation of SOCS1 in U2OS and MG­63 cells, while miR­29a inhibition led to the opposite results. Transfection with miR­29a mimics also promoted the apoptosis, and inhibited the invasion, migration and EMT process of OS cells, while it markedly reduced the nuclear translocation of p65 and IκB­α degradation. Treatment with 5­aza­2'­deoxycytidine worked together with miR­29a mimics to synergistically enhance the aforementioned effects. By contrast, the effects induced by miR­29a were partly reversed upon co­transfection with SOCS1 siRNA. In conclusion, miR­29a promoted the apoptosis, and inhibited the invasion, migration and EMT process of OS cells via inhibition of the SOCS1/NF­κB signalling pathway by directly targeting DNMT3B.

9.
Environ Sci Technol ; 53(18): 10695-10704, 2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31418552

RESUMO

Sulfur oxides (SOx) are important atmospheric trace species in both gas and particulate phases, and sulfate is a major component of atmospheric aerosol. One potentially important source of particulate sulfate formation is the oxidation of dissolved SO2 by organic peroxides, which comprises a major fraction of secondary organic aerosol (SOA). In this study, we investigated the reaction kinetics and mechanisms between SO2 and condensed-phase peroxides. pH-dependent aqueous phase reaction rate constants between S(IV) and organic peroxide standards were measured. Highly oxygenated organic peroxides with O/C > 0.6 in α-pinene SOA react rapidly with S(IV) species in the aqueous phase. The reactions between organic peroxides and S(IV) yield both inorganic sulfate and organosulfates (OS), as observed by electrospray ionization ion mobility mass spectrometry. For the first time, 34S-labeling experiments in this study revealed that dissolved SO2 forms OS via direct reactions without forming inorganic sulfate as a reactive intermediate. Kinetics of OS formation was estimated semiquantitatively, and such reaction was found to account for 30-60% of sulfur reacted. The photochemical box model GAMMA was applied to assess the implications of the measured SO2 consumption and OS formation rates. Our findings indicate that this novel pathway of SO2-peroxide reaction is important for sulfate formation in submicron aerosol.

10.
ACS Appl Mater Interfaces ; 11(30): 27064-27072, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31265238

RESUMO

Hybrid graphene-perovskite photodetectors embrace the excellent photoabsorption properties of perovskites and high carrier mobility of graphene in a single device. Here, we demonstrate the integration of halide-ion-exchanged CsPbBrxI3-x nanocrystals (NCs) as a photoabsorber and graphene as a transport layer. The NCs conform to a cubic lattice structure and exhibit an optical band gap of 1.93 eV. The hybrid device attained a maximum responsivity of 1.13 × 104 A/W and specific detectivity of 1.17 × 1011 Jones in low light intensity (∼80 µW/cm2). Specifically, an ultrahigh photoconductive gain of 9.32 × 1010 is attained because of fast hole transit time in the graphene transistor and long recombination lifetime in the perovskite NCs simultaneously. The phototransistor also shows good stability and can maintain ∼95% of the photocurrent under continuous illumination over 5 h and ∼82% under periodic illumination over 37 h. Our results also revealed that the common issue of ion separation and segregated halide domains in mixed halide perovskite NCs do not occur under low light intensities. The intensive degradation of CsPbBrxI3-x NCs is only observed under stronger light excitation (≥55 mW/cm2), reflecting as emission shifts. Our work establishes the use of fully inorganic perovskite NCs as highly stable photodetectors with high responsivity and low power light detection.

11.
J Affect Disord ; 256: 532-535, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31280077

RESUMO

BACKGROUND: Suicidal ideation is a common phenomenon among postpartum women around the world. However, evidence of the relationship between neuroticism and suicidal ideation among postpartum women is still lacking. METHODS: From March 2017 to December 2018, a total of 1027 postpartum women (assessed no later than one month post-birth) were recruited to complete questionnaires assessing neuroticism, depression, anxiety and suicidal ideation. RESULTS: Anxiety and depression fully mediated the association between neuroticism and suicidal ideation (Total indirect effects = 0.11, 95%CI: 0.07, 0.15). The indirect effect of the pathway of EPQ (Neuroticism)-Anxiety-Suicidal ideation was more significant than other pathways (Indirect effects=0.04, 95%CI: 0.02, 0.07). CONCLUSION: Interventions for suicidal ideation in postpartum women need to target neuroticism and further research is necessary understand the mechanisms by which neuroticism affects suicidal ideation.

12.
N Engl J Med ; 381(11): 1001-1010, 2019 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-31340089

RESUMO

BACKGROUND: Roxadustat (FG-4592) is an oral inhibitor of hypoxia-inducible factor (HIF) prolyl hydroxylase that stimulates erythropoiesis and regulates iron metabolism. In phase 2 studies involving patients with chronic kidney disease, roxadustat increased levels of endogenous erythropoietin to within or near the physiologic range, along with increasing hemoglobin levels and improving iron homeostasis. Additional data are needed regarding the efficacy and safety of roxadustat for the treatment of anemia in patients with chronic kidney disease who are not undergoing dialysis. METHODS: In this phase 3 trial conducted at 29 sites in China, we randomly assigned 154 patients with chronic kidney disease in a 2:1 ratio to receive roxadustat or placebo three times a week for 8 weeks in a double-blind manner. All the patients had a hemoglobin level of 7.0 to 10.0 g per deciliter at baseline. The randomized phase of the trial was followed by an 18-week open-label period in which all the patients received roxadustat; parenteral iron was withheld. The primary end point was the mean change from baseline in the hemoglobin level, averaged over weeks 7 through 9. RESULTS: During the primary-analysis period, the mean (±SD) change from baseline in the hemoglobin level was an increase of 1.9±1.2 g per deciliter in the roxadustat group and a decrease of 0.4±0.8 g per deciliter in the placebo group (P<0.001). The mean reduction from baseline in the hepcidin level (associated with greater iron availability) was 56.14±63.40 ng per milliliter in the roxadustat group and 15.10±48.06 ng per milliliter in the placebo group. The reduction from baseline in the total cholesterol level was 40.6 mg per deciliter in the roxadustat group and 7.7 mg per deciliter in the placebo group. Hyperkalemia and metabolic acidosis occurred more frequently in the roxadustat group than in the placebo group. The efficacy of roxadustat in hemoglobin correction and maintenance was maintained during the 18-week open-label period. CONCLUSIONS: In Chinese patients with chronic kidney disease who were not undergoing dialysis, those in the roxadustat group had a higher mean hemoglobin level than those in the placebo group after 8 weeks. During the 18-week open-label phase of the trial, roxadustat was associated with continued efficacy. (Funded by FibroGen and FibroGen [China] Medical Technology Development; ClinicalTrials.gov number, NCT02652819.).


Assuntos
Anemia/tratamento farmacológico , Glicina/análogos & derivados , Hemoglobinas/análise , Prolina Dioxigenases do Fator Induzível por Hipóxia/antagonistas & inibidores , Isoquinolinas/uso terapêutico , Insuficiência Renal Crônica/complicações , Acidose/induzido quimicamente , Adulto , Idoso , Anemia/etiologia , Colesterol/sangue , Método Duplo-Cego , Feminino , Glicina/efeitos adversos , Glicina/uso terapêutico , Hematínicos/efeitos adversos , Hematínicos/uso terapêutico , Humanos , Hiperpotassemia/induzido quimicamente , Isoquinolinas/efeitos adversos , Masculino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/sangue
13.
Artigo em Inglês | MEDLINE | ID: mdl-31243792

RESUMO

Retinal degeneration (RD) results in photoreceptor loss and irreversible visual impairments. This study sought to alleviate the photoreceptor degeneration via the adeno-associated virus (AAV)-mediated erythropoietin (EPO) therapy. AAV-2/2-mCMV-EPO vectors were constructed and delivered into the subretinal space of a RD model. The retinal morphology, optokinetic behaviour and electrophysiological function of the treated animals were analysed. The subretinal delivery of AAV-2/2 vectors induced robust EPO gene expressions in the retinas. AAV2/2-mediated EPO therapy ameliorated the photoreceptor degeneration and visual impairments of the RD animal model. Furthermore, the multi-electrodes array (MEA) was used to detect the firing activities of retinal ganglion cells. MEA recording showed that the EPO therapy could restrain the spontaneous firing response, enhance the light-induced firing response and preserve the basic configurations of visual signal pathway in RD model. Our MEA assay provided an example to evaluate the potency of pharmacological compounds on retinal plasticity. In conclusion, AAV2/2-mediated EPO therapy can ameliorate the photoreceptor degeneration and rectify the abnormities in visual signal transmission. These beneficial results suggest the AAV vector is a viable therapeutic option for retinopathies with rapidly degenerating kinetics and lay the groundwork for future development of EPO gene therapy.

14.
Sheng Wu Gong Cheng Xue Bao ; 35(5): 901-909, 2019 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-31223008

RESUMO

To establish a novel colloidal gold immunochromatography assay (GICA) for rapid, sensitive and accurate detection of Haemophilus influenzae infection by using the outer membrane protein P6 as detection target. First, the linear antigen epitope located in the extracellular domain of the P6 protein (GenBank accession number: AGH02799) was predicted by bioinformatics analysis. The region (62-75 aa of the protein) with strong antigen specificity was chosen and synthesized. Two rabbits were then immunized by the polypeptides (14 aa) for production of polyclonal antibodies. Then, the recombinant P6 proteins were also obtained to produce polyclonal antibodies. Finally, based on the two antibodies, a novel colloidal GICA for detection of Haemophilus influenzae infection was established and the specificity, sensitivity, repeatability and stability of this method were evaluated. At the same time, the method was tested in clinical simulation, and the plate culture method was used to verify its accuracy. The test strip for Haemophilus influenzae infection was successfully prepared. The detection limit of the test strip was as low as 1×105 CFU/mL and the whole process can be completed within 15 minutes. The strip specifically recognized Haemophilus influenzae and did not react with nine of other common respiratory pathogens such as Streptococcus pneumoniae, Moraxella catarrhalis, Mycoplasma pneumonia, and Legionella pneumophila. And the strips could be stored at 25 °C for at least 6 months without losing sensitivity or specificity. The coincidence rate between the results of 200 clinical samples and the plate culture method was 90.5%. Haemophilus influenzae protein P6, which possessed a high degree of surface antigen accessibility and antigencity, could be used as a marker for Haemophilus influenzae detection. The immunochromatographic colloidal gold test strip which bears the features of rapidity, convenience and sensitivity provides a unique tool for the on-site surveillance and diagnosis of Haemophilus influenzae infection in clinical test.


Assuntos
Cromatografia de Afinidade , Coloide de Ouro , Infecções por Haemophilus , Haemophilus influenzae , Animais , Cromatografia de Afinidade/instrumentação , Testes Diagnósticos de Rotina/normas , Coloide de Ouro/química , Infecções por Haemophilus/diagnóstico , Humanos , Limite de Detecção , Coelhos , Sensibilidade e Especificidade
15.
Chem Commun (Camb) ; 55(51): 7358-7361, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31172143

RESUMO

Here, we describe a simple mix-and-read method for the detection of specific bacterial strains that uses a DNAzyme and a molecular beacon to generate a signal. We have greatly improved upon the previously described DNAzyme-based bacteria detection method by eliminating a tedious preparation step while maintaining detection sensitivity.


Assuntos
Extratos Celulares/análise , DNA Bacteriano/análise , DNA Catalítico/metabolismo , DNA de Cadeia Simples/análise , Escherichia coli/classificação , Técnicas Biossensoriais , Corantes Fluorescentes/química , Limite de Detecção
16.
Int J Environ Health Res ; : 1-12, 2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31140839

RESUMO

To evaluate the association of environmental tobacco smoke (ETS) exposure with hypertension and blood pressure (BP) in children, a sample of 9,354 children, aged 5-17 years, was studied from seven northeastern cities of China in 2012-2013. The results showesd that significant associations were observed for hypertension with ETS exposure in utero [odds ratio (OR) 1.36, 95% confidence interval (CI) 1.18-1.57], with current major ETS exposure from fathers (1.38, 1.21-1.57) or anyone (1.26, 1.12-1.42), and with intensity of ETS exposure greater than 1 cigarette per day (ORs ranged from 1.20 to 1.35). For SBP, significant associations were only observed in children with major ETS exposure from father and with cigarettes smoking >10/day. When stratified by sex, more significant associations were found in girls than in boys. In conclusion, prenatal and postnatal ETS exposure was significantly associated with increased odds of hypertension in children, especially in girls.

17.
J Agric Food Chem ; 67(24): 6828-6836, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31136163

RESUMO

Verticillium wilt, caused by Verticillium dahliae, results in a dramatic loss of cotton yields in China. There is great potential for biocontrol to manage this destructive crop disease. In this study, we obtained the endophytic bacterium Bacillus halotolerans Y6 from Verticillium wilt-resistant cotton Gossypium barbadense Xinhai15; this bacterium possesses strong antagonistic abilities that inhibit V. dahliae spore germination and mycelial growth. The results of the enzyme activity assay, heterologous expression, and gene knockdown showed that the key virulence factor of Y6 for antagonizing V. dahliae was ß -glucanase Bgy6. To facilitate field tests of biological control, we constructed the homologous Bgy6-overexpression strain OY6. Compared with the wild-type Y6 strain, the ß-glucanase activity of OY6 was increased by 91.79%, and the inhibition rate of OY6 against V. dahliae V991 exceeded 96.7%. Moreover, the spores of V. dahliae V991 treated with OY6 showed more mucus and larger holes on the surface, as observed by scanning electron microscopy. Potting test results illustrated that both OY6 and Y6 could improve the resistance of upland cotton to Verticillium wilt. With the inoculation of V. dahliae V991 for 45 days, the disease index of G. hirsutum TM-1 treated with OY6 was only 8.33, which was significantly lower than that in plants treated with the wild-type strain Y6 (17.86) or the controls without bacteria (35.94). Our research provides a new idea for the control of Verticillium wilt in upland cotton via transforming endophytic bacteria of Verticillium wilt-resistant cotton and proposes a new solution to prevent and control Verticillium wilt.


Assuntos
Bacillus/enzimologia , Proteínas de Bactérias/genética , Endo-1,3(4)-beta-Glucanase/genética , Endófitos/enzimologia , Gossypium/microbiologia , Doenças das Plantas/imunologia , Verticillium/fisiologia , Fatores de Virulência/genética , Antibiose , Bacillus/genética , Bacillus/isolamento & purificação , Bacillus/fisiologia , Proteínas de Bactérias/metabolismo , Resistência à Doença , Endo-1,3(4)-beta-Glucanase/metabolismo , Endófitos/genética , Endófitos/isolamento & purificação , Endófitos/fisiologia , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Gossypium/imunologia , Doenças das Plantas/microbiologia , Fatores de Virulência/imunologia
18.
Hum Brain Mapp ; 40(12): 3606-3619, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31062891

RESUMO

In covert visual attention, one fundamental question is how advance knowledge facilitates subsequent neural processing and behavioral performance. In this study, with a rapid event-related simultaneous electroencephalography (EEG) and functional near infrared spectroscopy recording in humans, we explored the potential contribution of anticipatory electrophysiological activation and hemodynamic activation by examining how anticipatory low-frequency oscillations and changes in oxygenated hemoglobin (HbO) concentration influence the subsequent event-related potential (ERP) marker of attentional selection. We found that expecting a target led to both a posterior lateralization of alpha-band (8-12 Hz) oscillation power and a lateralization of HbO response over the visual cortex. Importantly, the magnitude of cue-induced alpha lateralization was positively correlated with the nearby HbO lateralization in the visual cortex, and such a cue-induced alpha lateralization predicted the subsequent target-evoked N2pc amplitudes assumed to reflect attentional selection. Our results suggest that each individual's attentional selection biomarker as reflected by N2pc is predictable in advance via the anticipation-induced alpha lateralization, and such cue-induced alpha lateralization seems to play an important role in the functional coupling effects between the low-frequency EEG and the nearby hemodynamic activation.

19.
Anal Chem ; 91(9): 5729-5738, 2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-30938976

RESUMO

We propose a simplified multifunctional traffic control approach that effectively combines dielectrophoresis (DEP) and alternating current electrothermal (ACET) flow to realize continuous particle trapping, switching, and sorting. In the designed microsystem, the combined DEP and ACET effects, which are symmetrically generated above a bipolar electrode surface, contribute to focus the incoming colloidal particles into a thin beam. Once the bipolar electrode is energized with an electric gate signal completely in phase with the driving alternating current (AC) signal, the spatial symmetry of the electric field can be artificially reordered by adjusting the gate voltage through field-effect traffic control. This results in a reshapable field stagnant region for precise switching of particles into the region of interest. Moreover, the integrated particle switching prior to the scaled particle trapping experiment is successfully conducted to demonstrate the feasibility of the combined strategy. Furthermore, a mixture of two types of particle sorting (i.e., density, size) with quick response performance is achieved by increasing the driving voltage with a maximum gate voltage offset, thus, extending the versatility of the designed device. Finally, droplet switching and filtration of the satellite droplets from the parent droplets is performed to successfully permit control of the droplet traffic. The proposed traffic control approach provides a promising technique for flexible manipulation of particulate samples and can be conveniently integrated with other micro/nanofluidic components into a complete functional on-chip platform owing to its simple geometric structure, easy operation, and multifunctionality.

20.
ACS Appl Mater Interfaces ; 11(10): 9691-9695, 2019 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-30816689

RESUMO

Investigations on luminescence properties of lanthanide-activated phosphors are not only essential to understanding the fundamental structure-property relationship but also important to advancing the development and application of relevant research techniques. We report herein a promising optical thermometric material Eu2+-doped Li4SrCa(SiO4)2 utilizing the different sensitivities of EuSr2+ and EuCa2+ emission intensities to temperature. A unique evolution of Eu2+ luminescence in the as-prepared sample is identified under the simultaneous action of UV illumination and thermal treatment. The maximum relative sensitivities are 2.87% K-1 (at 440 K) and 1.51% K-1 (at 460 K) for the as-prepared and illuminated samples, respectively. These temperature sensing features reflect a great potential of Eu2+-doped Li4SrCa(SiO4)2 for applications in the optical thermometry field.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA