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1.
Phytopathology ; 109(7): 1293-1301, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30852972

RESUMO

Strawberry anthracnose fruit rot and root necrosis, caused by Colletotrichum acutatum, are primary limiting factors in fruit production fields in the United States. Recent research focusing on the phenotypic and genetic characteristics of this species has shed light on the diversity of the C. acutatum species complex. In this study, we performed multilocus sequence analysis of four genetic loci to characterize 217 C. acutatum isolates collected over a 23-year period from symptomatic plant tissues of strawberry from six different states. The results revealed two Colletotrichum spp. (C. nymphaeae and C. fioriniae), with 97.7% of the isolate collection (212 of 217) belonging to C. nymphaeae as a dominant clonal linage, regardless of the isolation source. No correlation between species groups and geographical origins of the isolates was observed. Further sequence comparison between historical and contemporary isolates showed the same populations being widely distributed throughout the strawberry nurseries and production fields in the United States and Canada. Subsequently, a subset of 12 isolates representing different quinone-outside inhibitor fungicide resistance profiles from root or fruit tissue of strawberry was selected for comparison of pathogenicity on strawberry. In this test, isolates of different resistance groups or different isolation sources exhibited a similar degree of aggressiveness and caused indistinguishable symptoms on strawberry crowns (P = 0.9555 and 0.7873, respectively) and fruit (P = 0.1638 and 0.1141, respectively), although a significant difference among individual isolates was observed in detached-fruit assays (P = 0.0123). Separate pathogenicity tests using isolates of the two species revealed C. nymphaeae being more aggressive than C. fioriniae in infecting strawberry roots and crowns (P = 0.0073). Therefore, given the occurrence and pathogenicity of C. nymphaeae, this species is likely the sole cause responsible for strawberry anthracnose in the United States.


Assuntos
Colletotrichum , Fragaria , Doenças das Plantas/microbiologia , Canadá , Fragaria/microbiologia , Frutas , Estados Unidos
2.
Curr Cancer Drug Targets ; 19(9): 716-728, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30727895

RESUMO

BACKGROUND: Autophagy and apoptosis are the basic physiological processes in cells that clean up aged and mutant cellular components or even the entire cells. Both autophagy and apoptosis are disrupted in most major diseases such as cancer and neurological disorders. Recently, increasing attention has been paid to understand the crosstalk between autophagy and apoptosis due to their tightly synergetic or opposite functions in several pathological processes. OBJECTIVE: This study aims to assist autophagy and apoptosis-related drug research, clarify the intense and complicated connections between two processes, and provide a guide for novel drug development. METHODS: We established two chemical-genomic databases which are specifically designed for autophagy and apoptosis, including autophagy- and apoptosis-related proteins, pathways and compounds. We then performed network analysis on the apoptosis- and autophagy-related proteins and investigated the full protein-protein interaction (PPI) network of these two closely connected processes for the first time. RESULTS: The overlapping targets we discovered show a more intense connection with each other than other targets in the full network, indicating a better efficacy potential for drug modulation. We also found that Death-associated protein kinase 1 (DAPK1) is a critical point linking autophagy- and apoptosis-related pathways beyond the overlapping part, and this finding may reveal some delicate signaling mechanism of the process. Finally, we demonstrated how to utilize our integrated computational chemogenomics tools on in silico target identification for small molecules capable of modulating autophagy- and apoptosis-related pathways. CONCLUSION: The knowledge-bases for apoptosis and autophagy and the integrated tools will accelerate our work in autophagy and apoptosis-related research and can be useful sources for information searching, target prediction, and new chemical discovery.

3.
Phytopathology ; 109(4): 650-658, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30412011

RESUMO

Citrus black spot, caused by Phyllosticta citricarpa, has been identified in Florida since 2010 and can reduce fruit yield and marketability. The conditions required for conidial germination have been poorly understood for P. citricarpa, limiting further biological studies. In this study, the effects of citrus juices, concentration, pH, various carbon and nitrogen sources, and environmental conditions were evaluated in vitro. All tested juices, especially 'Valencia' (>85%, P < 0.05), favored germination and appressorium formation, whereas sterile water rarely stimulated germination (<1%). The 'Valencia' juice effect was concentration and pH dependent, and the maximum rate was reached in 1.5% juice with pH of 3.4. Most carbon, nitrogen, or complex sources did not favor germination or appressorium formation, with the exception of potato dextrose broth. An incubation period of 18 to 24 h at 24°C was required for peak germination and appressorium formation. The further analysis of critical juice components using synthetic citrus juice revealed that sugars, salts, citric acid, and thiamine were most important for germination and appressorium formation (>80%, P > 0.05). These results provide a better understanding of fungal biology of P. citricarpa and a robust and convenient system for further applications such as screening for efficacious fungicides.


Assuntos
Ascomicetos , Citrus , Sucos de Frutas e Vegetais , Hifas , Esporos Fúngicos , Ascomicetos/crescimento & desenvolvimento , Citrus/microbiologia , Florida , Sucos de Frutas e Vegetais/microbiologia , Doenças das Plantas
4.
Phytopathology ; 108(4): 462-468, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29135359

RESUMO

Quinone-outside inhibitor (QoI) fungicides are used to manage anthracnose of strawberry, caused by Colletotrichum acutatum. However, selection for resistance to QoI fungicides was first reported in 2013 in Florida and, subsequently, in strawberry nurseries and production areas across the United States and Canada. C. acutatum resistance to QoIs is associated with the G143A point mutation in the cytochrome b gene. This mutation is known to be associated with field resistance even at high rates of QoI. In this study, we investigated the relative fitness and competitive ability of QoI-resistant and -sensitive C. acutatum isolates. A fitness comparison did not indicate any difference between resistant and sensitive isolates in aggressiveness, spore production, and mycelial growth at different temperatures. Additionally, in the absence of selection pressure, resistant and sensitive isolates were equally competitive. Cultivation of QoI-resistant and QoI-sensitive isolates for four culture cycles in vitro in the absence of azoxystrobin showed that QoI resistance was stable. The observed lack of fitness penalties and stability of the G143A mutation in QoI-resistant C. acutatum populations suggest that the interruption and further reintroduction of QoI fungicides might not be an option for strawberry nurseries and fruit production areas. Further investigation of alternative chemical and nonchemical C. acutatum control practices, in addition to the integration of multisite fungicides, is needed to reduce the occurrence and distribution of QoI-resistant populations in strawberry fields.


Assuntos
Colletotrichum/fisiologia , Citocromos b/genética , Farmacorresistência Fúngica/genética , Fragaria/microbiologia , Doenças das Plantas/microbiologia , Pirimidinas/farmacologia , Estrobilurinas/farmacologia , Substituição de Aminoácidos , Canadá , Colletotrichum/efeitos dos fármacos , Colletotrichum/genética , Florida , Frutas/efeitos dos fármacos , Proteínas Fúngicas/genética , Fungicidas Industriais/farmacologia , Genótipo , Mutação Puntual
5.
J Chem Inf Model ; 57(11): 2686-2698, 2017 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-29016123

RESUMO

Molecular docking is widely applied to computer-aided drug design and has become relatively mature in the recent decades. Application of docking in modeling varies from single lead compound optimization to large-scale virtual screening. The performance of molecular docking is highly dependent on the protein structures selected. It is especially challenging for large-scale target prediction research when multiple structures are available for a single target. Therefore, we have established ProSelection, a docking preferred-protein selection algorithm, in order to generate the proper structure subset(s). By the ProSelection algorithm, protein structures of "weak selectors" are filtered out whereas structures of "strong selectors" are kept. Specifically, the structure which has a good statistical performance of distinguishing active ligands from inactive ligands is defined as a strong selector. In this study, 249 protein structures of 14 autophagy-related targets are investigated. Surflex-dock was used as the docking engine to distinguish active and inactive compounds against these protein structures. Both t test and Mann-Whitney U test were used to distinguish the strong from the weak selectors based on the normality of the docking score distribution. The suggested docking score threshold for active ligands (SDA) was generated for each strong selector structure according to the receiver operating characteristic (ROC) curve. The performance of ProSelection was further validated by predicting the potential off-targets of 43 U.S. Federal Drug Administration approved small molecule antineoplastic drugs. Overall, ProSelection will accelerate the computational work in protein structure selection and could be a useful tool for molecular docking, target prediction, and protein-chemical database establishment research.


Assuntos
Algoritmos , Simulação por Computador , Descoberta de Drogas/métodos , Simulação de Acoplamento Molecular , Proteínas/química , Proteínas/metabolismo , Bases de Dados de Proteínas , Ligantes , Conformação Proteica
6.
Angew Chem Int Ed Engl ; 55(41): 12678-82, 2016 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-27625114

RESUMO

A sandwich FAU-LTA zeolite dual-layer membrane has been developed and used as a catalytic membrane reactor for the synthesis of dimethyl ether (DME). In the top H-FAU layer with mild acidity, methanol is dehydrated to DME. The other reaction product, water, is removed in situ through a hydrophilic Na-LTA layer, which is located between the porous alumina support and the H-FAU top layer. The combination of mild acidity with the continuous removal of water results in high methanol conversion (90.9 % at 310 °C) and essentially 100 % DME selectivity. Furthermore, owing to the selective and continuous removal of water through the Na-LTA membrane, catalyst deactivation can be effectively suppressed.

7.
Phytopathology ; 106(11): 1300-1310, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27348343

RESUMO

Phyllosticta citricarpa, the citrus black spot pathogen, was first identified in Florida in March 2010. Subsequently, this pathogen has become established in Florida but can be easily confused with the endemic nonpathogenic citrus endophyte P. capitalensis. In this study, the mating-type (MAT) loci of P. citricarpa and P. capitalensis were identified via draft genome sequencing and were characterized at the structural and sequence levels. P. citricarpa was determined to have an idiomorphic, heterothallic MAT locus structure, whereas P. capitalensis was found to have a single MAT locus consistent with a homothallic mating system. A survey of P. citricarpa isolates from Florida revealed that only the MAT1-2 idiomorph existed in the Floridian population. In contrast, isolates collected from Australia exhibited a 1:1 ratio of MAT1-1 and MAT1-2 isolates. Development and analysis of simple sequence repeat markers revealed a single multilocus genotype (MLG) in the Floridian population (n = 70) and 11 MLG within the Australian population (n = 24). These results indicate that isolates of P. citricarpa from Florida are likely descendent from a single clonal lineage and are reproducing asexually. The disease management focus in Florida will need to be concentrated on the production and dispersal of pycnidiospores.


Assuntos
Ascomicetos/genética , Citrus/microbiologia , Genes Fúngicos Tipo Acasalamento/genética , Repetições de Microssatélites/genética , Doenças das Plantas/microbiologia , Ascomicetos/isolamento & purificação , Endófitos , Florida , Loci Gênicos/genética , Marcadores Genéticos , Variação Genética , Genética Populacional , Filogenia , Análise de Sequência de DNA , Sintenia
8.
Chem Commun (Camb) ; 52(5): 974-7, 2016 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-26588178

RESUMO

A total of 41,825 metal-organic frameworks (MOFs) were computationally screened toward the design of amine-functionalized MOFs for CO2 separation. Both the optimal species and number of amine functional groups were examined for eight MOFs with good performance in terms of CO2 uptake and selectivity. It was revealed that more amine functional groups grafted on the MOFs do not lead to a better CO2 separation capability, and the concept of saturation degree of functional groups was proposed. The ethylene-diamine-functionalized MOF-74 membrane was predicted to possess high CO2 permeation separation capability, which was confirmed by the parallel experimental test of gas permeation.

9.
ChemSusChem ; 8(21): 3582-6, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26427908

RESUMO

Significantly enhanced H2 /CH4 (ca. 80) selectivity was realized by effective suppression of the framework flexibility of a prepared ZIF-8 membrane. Initially a ZnO buffer layer consisting of 20 nm-sized ZnO-nanoparticle aggregates was fabricated by controlled calcination of a ZnAl-NO3 layered double hydroxide membrane. Owing to its high chemical reactivity, the ZnO buffer layer was partially converted into a well-intergrown ZIF-8 membrane with a certain penetration depth upon solvothermal treatment with ligands. Our method may represent a new concept for the design of advanced MOF membranes with high selectivity.


Assuntos
Gases/isolamento & purificação , Hidróxidos/química , Membranas Artificiais , Nanopartículas/química , Compostos Organometálicos/química , Óxido de Zinco/química , Hidrogênio/isolamento & purificação , Metano/isolamento & purificação , Microscopia Eletrônica de Varredura , Porosidade , Propriedades de Superfície
10.
Angew Chem Int Ed Engl ; 54(10): 3028-32, 2015 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-25611948

RESUMO

Separation methods based on 2D interlayer galleries are currently gaining widespread attention. The potential of such galleries as high-performance gas-separation membranes is however still rarely explored. Besides, it is well recognized that gas permeance and separation factor are often inversely correlated in membrane-based gas separation. Therefore, breaking this trade-off becomes highly desirable. Here, the gas-separation performance of a 2D laminated membrane was improved by its partial self-conversion to metal-organic frameworks. A ZIF-8-ZnAl-NO3 layered double hydroxide (LDH) composite membrane was thus successfully prepared in one step by partial conversion of the ZnAl-NO3 LDH membrane, ultimately leading to a remarkably enhanced H2 /CH4 separation factor and H2 permeance.

11.
J Am Chem Soc ; 136(41): 14353-6, 2014 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-25280264

RESUMO

We develop here a urea hydrolysis method to in situ prepare asymmetric ZnAl-CO3 layered double hydroxide (LDH) buffer layers with various stable equilibrium morphology on porous Al2O3 substrates. In particular it is found that well-intergrown ZIF-8 membranes can be directly synthesized on the ZnAl-CO3 LDH buffer layer-modified substrates, owing to the specific metal-imidazole interaction between ZnAl-CO3 LDHs and ZIF-8. Other Zn-based MOF membranes, like ZIF-7 and ZIF-90, can also be synthesized with this method. Our finding demonstrates that LDH buffer layer represents a new concept for substrate modification.

12.
J Am Chem Soc ; 136(42): 14686-9, 2014 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-25290574

RESUMO

Through layer-by-layer (LBL) deposition of a graphene oxide (GO) suspension on a semicontinuous ZIF-8 layer, we have developed a novel bicontinuous ZIF-8@GO membrane. Since only the gaps between the ZIF-8 crystals are sealed by the GO layer due to capillary forces and covalent bonds, the gas molecules can only permeate through the ZIF-8 micropore system (0.34 nm). Therefore, the ZIF-8@GO membranes show high hydrogen selectivity. At 250 °C and 1 bar, the mixture separation factors of H2/CO2, H2/N2, H2/CH4, and H2/C3H8 are 14.9, 90.5, 139.1, and 3816.6, with H2 permeances of about 1.3 × 10(-7) mol·m(-2)·s(-1)·Pa(-1), which is promising for hydrogen separation and purification by molecular sieving.

13.
Biomed Res Int ; 2014: 258402, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24804207

RESUMO

The bulbs of cultivated Fritillaria cirrhosa (BCFC) are used in China both for food and folk medicine due to its powerful biological activities. The aim of this study is to optimize the extraction and enrichment conditions of alkaloids from BCFC. Firstly, the orthogonal experimental design was used to optimize and evaluate four variables (ethanol concentration, solid-liquid ratio, extraction time, and temperature). Thereafter, resin adsorption was as a means to enrich alkaloids. Among 16 tested resins, H-103 resin presented higher adsorption capacity and desorption ratio. The equilibrium experimental data of the adsorption of total alkaloids, imperialine, and peimisine were well-fitted to the pseudo-first-order kinetics model, Langmuir and Freundlich isotherms models. Finally, in order to optimize the parameters for purifying alkaloids, dynamic adsorption and desorption tests were carried out. After one run treatment with H-103 resin, the contents of total alkaloids, imperialine, and peimisine in the product were 21.40-, 18.31-, and 22.88-fold increased with recovery yields of 94.43%, 90.57%, and 96.16%, respectively.


Assuntos
Alcaloides/química , Alcaloides/isolamento & purificação , Fritillaria/química , Esteroides/química , Esteroides/isolamento & purificação
14.
Chem Commun (Camb) ; 50(32): 4225-7, 2014 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-24627890

RESUMO

MOF membranes have gained widespread attention due to their unprecedented gas separation performance. Relying on physical interactions, we successfully deposited MOF seeds on a substrate modified with a network of vertically aligned LDH walls before secondary growth of the MOF layer. ZIF-8 membranes thus prepared show considerable H2 permeance with high H2-CH4 selectivity. This approach is in general suitable for the deposition of nanoparticles on solid surface and their subsequent growth into a dense layer.

15.
Plant Dis ; 98(1): 112-120, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30708603

RESUMO

Citrus black spot, a major citrus disease caused by Guignardia citricarpa, was recently introduced in Florida. The nonpathogenic fungal endophyte G. mangiferae is commonly found in the same citrus tissues as G. citricarpa. Quantitative polymerase chain reaction (qPCR) assays based on internal transcribed spacer (ITS)-1 genes were developed to detect, quantify, and distinguish between these morphologically similar organisms in environmental samples. The primer/probe sets GCITS and GMITS were more than 95% efficient in single-set reactions in complex environmental DNA samples. Detection of 10 fg of G. citricarpa and G. mangiferae DNA was possible. Pycnidiospore disruption resulted in detection of single pycnidiospores with 78 (59 to 102; 95% confidence interval [CI]) and 112 (92 to 136; 95% CI) ITS copies for G. citricarpa and G. mangiferae, respectively. Detection was from partially decomposed leaves where fruiting bodies cannot be morphologically distinguished. Temperature and wetting period have significant effects on Guignardia spp. pseudothecia production in leaf litter. Based on relative biomass or the proportion of nuclei detected, G. citricarpa and G. mangiferae respond more strongly to wetting period than temperature. This qPCR assay will provide additional epidemiological data on black spot in tissues where G. citricarpa and G. mangiferae are not easily distinguished.

16.
Plant Dis ; 98(6): 780-789, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30708631

RESUMO

Citrus black spot (CBS), caused by Guignardia citricarpa, is an emerging disease in Florida. Fungicide applications are the main control measure worldwide. The in vitro activity and baseline sensitivity of G. citricarpa isolates to quinone outside inhibitor (QoI) fungicides (azoxystrobin and pyraclostrobin) were evaluated. The effective concentration needed to reduce mycelial growth or spore germination by 50% (EC50) was determined for 86 isolates obtained from Florida counties where CBS is found. The effect of salicylhydroxamic acid (SHAM) plus azoxystrobin and pyraclostrobin was also assessed for mycelial growth and conidial germination. The mean EC50 for mycelial growth for azoxystrobin was 0.027 µg/ml and that for pyraclostrobin was significantly lower at 0.007 µg/ml (P < 0.0001). Similarly, the mean EC50 for conidial germination for azoxystrobin was 0.016 µg/ml and that for pyraclostrobin was significantly lower at 0.008 µg/ml (P < 0.0001). There was no effect of SHAM on inhibition of mycelial growth or conidial germination by the QoI fungicides but SHAM slightly affected mycelium inhibition by pyraclostrobin. Cytochrome b was partially sequenced and three group 1 introns were found. One intron was immediately post G143, likely inhibiting resistance-conferring mutations at that site. It is surmised that the QoI resistance risk is low in the Florida G. citricarpa population.

17.
J Am Chem Soc ; 135(47): 17679-82, 2013 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-24224527

RESUMO

Inspired by the bioadhesive ability of the marine mussel, a simple, versatile, and powerful synthesis strategy was developed to prepare highly reproducible and permselective molecular sieve membranes by using polydopamine as a novel covalent linker. Attributing to the formation of strong covalent and noncovalent bonds, ZIF-8 nutrients are attracted and bound to the support surface, thus promoting the ZIF-8 nucleation and the growth of uniform, well intergrown, and phase-pure ZIF-8 molecular sieve membranes. The developed ZIF-8 membranes show high hydrogen selectivity and thermal stability. At 150 °C and 1 bar, the mixture separation factors of H2/CO2, H2/N2, H2/CH4, and H2/C3H8 are 8.9, 16.2, 31.5 and 712.6, with H2 permeances higher than 1.8 × 10(-7) mol·m(-2)·s(-1)·Pa(-1), which is promising for hydrogen separation and purification.


Assuntos
Óxido de Alumínio/química , Materiais Biomiméticos/química , Bivalves/química , Indóis/química , Membranas Artificiais , Polímeros/química , Animais , Porosidade
18.
Chem Commun (Camb) ; 48(89): 10981-3, 2012 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-23034485

RESUMO

Making use of the preferred adsorption affinity and capacity to CO(2) as well as the highly porous structure with huge cavities of 2.4 nm, a highly permeable and selective ZIF-95 molecular sieve membrane was developed for the separation of H(2) from CO(2).

19.
Angew Chem Int Ed Engl ; 51(42): 10551-5, 2012 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-22987754

RESUMO

A clear separation: A post-synthetic functionalization method is reported to obtain a highly permselective zeolitic imidazolate framework (ZIF-90) membrane. The intercrystalline defects of the ZIF-90 membrane are minimized to enhance the separation selectivity while a high permeance is maintained.

20.
Chem Commun (Camb) ; 48(29): 3542-4, 2012 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-22378243

RESUMO

Sandwich-structured composite zeolite membranes with enhanced hydrogen selectivity were prepared on porous α-Al(2)O(3) supports by using 3-aminopropyltriethoxysilane as an interlayer.

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