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1.
Nature ; 609(7926): 269-275, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-36071190

RESUMEN

Nuclear fusion is one of the most attractive alternatives to carbon-dependent energy sources1. Harnessing energy from nuclear fusion in a large reactor scale, however, still presents many scientific challenges despite the many years of research and steady advances in magnetic confinement approaches. State-of-the-art magnetic fusion devices cannot yet achieve a sustainable fusion performance, which requires a high temperature above 100 million kelvin and sufficient control of instabilities to ensure steady-state operation on the order of tens of seconds2,3. Here we report experiments at the Korea Superconducting Tokamak Advanced Research4 device producing a plasma fusion regime that satisfies most of the above requirements: thanks to abundant fast ions stabilizing the core plasma turbulence, we generate plasmas at a temperature of 100 million kelvin lasting up to 20 seconds without plasma edge instabilities or impurity accumulation. A low plasma density combined with a moderate input power for operation is key to establishing this regime by preserving a high fraction of fast ions. This regime is rarely subject to disruption and can be sustained reliably even without a sophisticated control, and thus represents a promising path towards commercial fusion reactors.

2.
Phys Rev Lett ; 128(22): 225001, 2022 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-35714255

RESUMEN

We present a gyrokinetic analysis of the vortex flow evolution in a magnetic island in collisionless tokamak plasmas. In a short term ω[over ¯]_{D}t<1, where ω[over ¯]_{D} is the secular magnetic drift of the orbit center, initial monopolar vortex flow approaches to its residual level determined by the neoclassical enhancement of polarization shielding after collisionless relaxation. The residual level depends on the location inside an island and is higher than the Rosenbluth-Hinton level [M.N. Rosenbluth and F.L. Hinton, Phys. Rev. Lett. 80, 724 (1998)PRLTAO0031-900710.1103/PhysRevLett.80.724] due to finite island width. In a long term ω[over ¯]_{D}t>1, the residual vortex flow evolves to a dipolar zonal-vortex flow mixture due to toroidicity-induced breaking of a helical symmetry. The mixture forms localized flow shear layers near the island separatrix away from X points. The deviation of the streamlines of the mixture flows from magnetic surfaces allows turbulence advection across the island. We expect a small island w≲qρ_{Ti}/s[over ^] provides a favorable condition for this mixture flow formation, while the monopolar vortex flow persists for a larger island.

3.
Phys Rev Lett ; 128(18): 185001, 2022 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-35594094

RESUMEN

Global gyrokinetic simulations of mesoscale reversed shear Alfven eigenmodes (RSAE) excited by energetic particles (EP) in fusion plasmas find that RSAE amplitude and EP transport are much higher than experimental levels at nonlinear saturation, but quickly diminish to very low levels after the saturation if background microturbulence is artificially suppressed. In contrast, in simulations coupling micro-meso scales, the RSAE amplitude and EP transport decrease drastically at the initial saturation but later increases to the experimental levels in the quasisteady state with bursty dynamics due to regulation by thermal ion temperature gradient (ITG) microturbulence. The quasisteady state EP transport is larger for a stronger microturbulence. The RSAE amplitude in the quasisteady state ITG-RSAE turbulence from gyrokinetic simulations, for the first time, agrees very well with experimental measurements.

4.
J Appl Microbiol ; 124(1): 144-154, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29072349

RESUMEN

AIMS: To identify the roles of the two O-methyltransferase homologous genes pdmF and pdmT in the pradimicin biosynthetic gene cluster of Actinomadura hibisca P157-2. METHODS AND RESULTS: Pradimicins are pentangular polyphenol antibiotics synthesized by bacterial type II polyketide synthases (PKSs) and tailoring enzymes. Pradimicins are naturally derivatized by combinatorial O-methylation at two positions (i.e., 7-OH and 11-OH) of the benzo[α]naphthacenequinone structure. PdmF and PdmT null mutants (PFKO and PTKO) were generated. PFKO produced the 11-O-demethyl shunt metabolites 11-O-demethylpradimicinone II (1), 11-O-demethyl-7-methoxypradimicinone II (2), 11-O-demethylpradimicinone I (3) and 11-O-demethylpradimicin A (4), while PTKO generated the 7-O-demethyl derivatives pradimicinone II (5) and 7-hydroxypradimicin A (6). Pradimicinones 1, 2, 3, and 5 were fed to a heterologous host Escherichia coli harbouring expression plasmid pET-22b::pdmF or pET-28a::pdmT. PdmF catalysed 11-O-methylation of pradimicinones 1, 2, and 3 regardless of O-methylation at the C-7 position, while PdmT was unable to catalyse 7-O-methylation when the C-11 hydroxyl group was methylated (5). CONCLUSIONS: PdmF and PdmT were involved in 11-O- and 7-O-methylations of the benzo[α]naphthacenequinone moiety of pradimicin, respectively. Methylation of the C-7 hydroxyl group precedes methylation of the C-11 hydroxyl group in pradimicin biosynthesis. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first reported demonstration of the functions of PdmF and PdmT for regiospecific O-methylation, which contributes to better understanding of the post-PKS modifications in pradimicin biosynthesis as well as to rational engineering of the pradimicin biosynthetic machinery.


Asunto(s)
Actinomycetales/metabolismo , Antraciclinas/metabolismo , Proteínas Bacterianas/química , Metiltransferasas/química , Actinomycetales/química , Actinomycetales/enzimología , Actinomycetales/genética , Antraciclinas/química , Antifúngicos/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Biocatálisis , Catálisis , Metilación , Metiltransferasas/genética , Metiltransferasas/metabolismo , Familia de Multigenes
5.
Lett Appl Microbiol ; 65(2): 133-140, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28585248

RESUMEN

Fusarium oxysporum, a causal agent of Fusarium wilt, is one of the most important fungal pathogens worldwide, and detection of F. oxysporum DNA at the forma specialis level is crucial for disease diagnosis and control. In this study, two novel F. oxysporum f. sp. raphani (For)-specific primer sets were designed, FOR1-F/FOR1-R and FOR2-F/FOR2-R, to target FOQG_17868 and FOQG_17869 ORFs, respectively, which were selected based on the genome comparison of other formae speciales of F. oxysporum including conglutinans, cubense, lycopersici, melonis, and pisi. The primer sets FOR1-F/FOR1-R and FOR2-F/FOR2-R that amplified a 610- and 425-bp DNA fragment, respectively, were specific to For isolates which was confirmed using a total of 40 F. oxysporum isolates. From infected plants, the FOR2-F/FOR2-R primer set directly detected the DNA fragment of For isolates even when the radish plants were collected in their early stage of disease development. Although the loci targeted by the For-specific primer sets were not likely involved in the pathogenesis, the primer set FOR2-F/FOR2-R is available for the determination of pathogenicity of radish-infecting F. oxysporum isolates. This study is the first report providing novel primer sets to detect F. oxysporum f. sp. raphani. SIGNIFICANCE AND IMPACT OF THE STUDY: Because plant pathogenic Fusarium oxysporum has been classified into special forms based on its host specificity, identification of F. oxysporum usually requires a pathogenicity assay as well as knowledge of the morphological characteristics. For rapid and reliable diagnosis, this study provides PCR primer sets that specifically detect Fusarium oxysporum f. sp. raphani (For) which is a devastating pathogen of radish plants. Because one of the primer sets directly detected the DNA fragment of For isolates from infected plants, the specific PCR method demonstrated in this study will provide a foundation for integrated disease management practices in commodity crops.


Asunto(s)
Fusarium/patogenicidad , Especificidad del Huésped , Enfermedades de las Plantas/microbiología , Raphanus/microbiología , Cartilla de ADN/genética , Fusarium/genética , Fusarium/aislamiento & purificación , Reacción en Cadena de la Polimerasa
6.
Acta Anaesthesiol Scand ; 61(1): 39-45, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27696339

RESUMEN

BACKGROUND: Sugammadex is a new agent that reverses neuromuscular blockade by aminosteroid neuromuscular blocker. This retrospective study compared the effects of sugammadex on post-operative nausea and vomiting (PONV) with those of a pyridostigmine-glycopyrrolate mixture. METHODS: We reviewed the electronic medical records of 7179 patients who had received fentanyl-based, intravenous, patient-controlled analgesia (IV-PCA) at Chung-Ang University Hospital between January 1, 2010 and December 31, 2015. We categorized the patients into two groups on the basis of the type of reversal agent to neuromuscular blockade that was used: a traditional reversal agent (pyridostigmine-glycopyrrolate mixture; Group R; n = 7059) and sugammadex (Group S; n = 120). The propensity score matching method was then used to select 408 subjects in Group R and 115 subjects in Group S; on the basis of their covariates, these subjects were then matched with a counterpart in the other group. RESULTS: After propensity score matching, the two groups were well balanced with respect to all baseline covariates. In Group S, the numeric rating scale of nausea on day 0, as well as the number of patients who vomited on day 0, was lower than that in group R. Furthermore, Group S used fewer rescue antiemetics on day 0 and had a higher complete response on day 0. CONCLUSION: Sugammadex might be more beneficial for PONV compared to pyridostigmine-glycopyrrolate mixture for patients who have received opioid-based IV-PCA.


Asunto(s)
Glicopirrolato/farmacología , Náusea y Vómito Posoperatorios/epidemiología , Puntaje de Propensión , Bromuro de Piridostigmina/farmacología , gamma-Ciclodextrinas/farmacología , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Dolor Postoperatorio/epidemiología , Estudios Retrospectivos , Sugammadex
7.
Anaesthesia ; 70(5): 613-22, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25693455

RESUMEN

We performed a systematic review to compare the efficacy and safety of the streamlined liner of the pharynx airway and laryngeal mask airway used in adults during general anaesthesia. We included 14 studies with studies with 1273 patients in total. There was no evidence of a difference between the two devices in insertion success rate on the first attempt (13 studies, 1143 patients), insertion time (seven studies, 576 patients), ease of insertion (five studies, 466 patients), oropharyngeal leak pressure (eight studies, 771 patients) and the quality of the fibreoptic view of the larynx through the device (three studies, 281 patients). The relative risk (95% CI) of bloodstaining of the device (nine studies, 859 patients) was 2.09 (1.46-3.00) for the streamlined liner of the pharynx airway compared with the laryngeal mask airway. Other adverse events were comparable. Subgroup analysis suggested that the insertion by novice users might be faster and more successful with the streamlined liner of the pharynx airway than the laryngeal mask airway; however, this was from only two studies and 186 patients. The method of size selection of the streamlined liner of the pharynx airway device might also affect the speed of insertion: choosing according to the width of the patient's thyroid cartilage, rather than height, may produce better results.


Asunto(s)
Manejo de la Vía Aérea/instrumentación , Intubación Intratraqueal/instrumentación , Máscaras Laríngeas , Faringe , Competencia Clínica , Diseño de Equipo , Humanos , Intubación Intratraqueal/métodos
8.
Acta Anaesthesiol Scand ; 59(2): 224-31, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25395384

RESUMEN

BACKGROUND: This study aimed to compare emergence agitation following sevoflurane and desflurane anaesthesia in adults undergoing orthognathic surgery. The hypothesis was that there might be a difference in the incidence of emergence agitation following sevoflurane and desflurane anaesthesia considering the difference in blood solubility and speed of recovery between the two. METHODS: In this prospective randomised double-blind study, 144 adults undergoing orthognathic surgery were randomly allocated to either sevoflurane or desflurane anaesthesia. The incidence of emergence agitation and possible causative factors were then compared between the groups. RESULTS: The incidence of emergence agitation was lower in the desflurane group than in the sevoflurane group (24% vs. 71%, P < 0.001). In addition, the time intervals between the discontinuation of anaesthetics and the first response, extubation, and discharge from post-anaesthesia care unit were significantly shorter in the desflurane group (P = 0.002, P < 0.001 and P = 0.003, respectively). The other variables were similar in the two groups. CONCLUSIONS: In adults undergoing orthognathic surgery, desflurane anaesthesia was associated with less emergence agitation than was sevoflurane anaesthesia.


Asunto(s)
Periodo de Recuperación de la Anestesia , Anestésicos por Inhalación/efectos adversos , Isoflurano/análogos & derivados , Éteres Metílicos/efectos adversos , Cirugía Ortognática , Agitación Psicomotora/epidemiología , Adolescente , Adulto , Desflurano , Método Doble Ciego , Femenino , Humanos , Isoflurano/efectos adversos , Corea (Geográfico)/epidemiología , Masculino , Estudios Prospectivos , Agitación Psicomotora/etiología , Sevoflurano , Adulto Joven
9.
Anaesthesia ; 69(11): 1258-65, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24866320

RESUMEN

We systematically reviewed randomised controlled trials of the i-gel® vs different types of laryngeal mask airway in children. We included nine studies. There was no evidence for differences in: rate of insertion at first attempt; insertion time; ease of insertion; or gastric tube insertion. The mean (95% CI) oropharyngeal leak pressure was 3.29 (2.25-4.34) cmH2 O higher with the i-gel, p < 0.00001. The relative rate (95% CI) of a good fibreoptic view through the i-gel was 1.10 (1.01-1.19), p = 0.02. There were no significant differences in the rates of complications, except for blood on the airway, relative rate with the i-gel 0.46 (0.23-0.91), p = 0.02. We concluded that the clinical performance of the i-gel and LMA was similar, except for three outcomes that favoured the i-gel.


Asunto(s)
Equipos Desechables , Máscaras Laríngeas , Niño , Preescolar , Humanos , Lactante , Intubación Intratraqueal/instrumentación
10.
J Appl Microbiol ; 115(5): 1172-85, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23910250

RESUMEN

AIMS: The purpose of this study was to isolate, identify and characterize an antifungal compound from Lactobacillus plantarum KCC-10 from forage silage with potential beneficial properties. METHODS AND RESULTS: The 16S rRNA gene-based phylogenetic affiliation was determined using bioinformatic tools and identified as Lactobacillus sp. KCC-10 with 100% sequence similarity to L. plantarum. The antifungal substances were extracted with ethyl acetate from spent medium in which Lactobacillus sp. KCC-10 was cultivated. Antifungal activity was assessed using the broth microdilution technique. The compounds were obtained by eluting the crude extract with various concentrations of solvents followed by chromatographic purification. Based on the infrared, (13) C nuclear magnetic resonance (NMR) and (1) H NMR spectral data, the compound was identified as a phenolic-related antibiotic. The minimum inhibitory concentration of the compound against Aspergillus clavatus, A. oryzae, Botrytis elliptica and Scytalidium vaccinii was 2.5 mg ml(-1) and that against A. fumigatus, A. niger and S. fusca was 5.0 mg ml(-1) , respectively. In addition, Lactobacillus sp. KCC-10 was highly sensitive towards oxgall (0.3%) but grew well in the presence of sodium taurocholate (0.3%). An antimicrobial susceptibility pattern was an intrinsic feature of this strain; thus, consumption does not represent a health risk to humans or animals. CONCLUSION: Novel L. plantarum KCC-10 with antifungal and potential probiotic properties was characterized for use in animal food. SIGNIFICANCE AND IMPACT OF THE STUDY: This study revealed that L. plantarum KCC-10 exhibited good antifungal activity similar to that of probiotic Lactobacillus strains.


Asunto(s)
Antifúngicos/química , Lactobacillus plantarum/química , Ensilaje/microbiología , Aminas/química , Antifúngicos/aislamiento & purificación , Aspergillus/efectos de los fármacos , Botrytis/efectos de los fármacos , Concentración de Iones de Hidrógeno , Lactobacillus plantarum/genética , Lactobacillus plantarum/aislamiento & purificación , Lolium/microbiología , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Fenoles/química , Fenoles/aislamiento & purificación , Filogenia , Probióticos , ARN Ribosómico 16S/genética
11.
Lett Appl Microbiol ; 51(5): 511-7, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20849392

RESUMEN

AIMS: This study is aiming at characterizing antifungal substances from the methanol extract of Prunella vulgaris and at investigating those substances' antifungal and antioomycete activities against various plant pathogens. METHODS AND RESULTS: Two polyacetylenic acids were isolated from P. vulgaris as active principles and identified as octadeca-9,11,13-triynoic acid and trans-octadec-13-ene-9,11-diynoic acid. These two compounds inhibited the growth of Magnaporthe oryzae, Rhizoctonia solani, Phytophthora infestans, Sclerotinia sclerotiorum, Fusarium oxysporum f. sp. raphani, and Phytophthora capsici. In addition, these two compounds and the wettable powder-type formulation of an n-hexane fraction of P. vulgaris significantly suppressed the development of rice blast, tomato late blight, wheat leaf rust, and red pepper anthracnose. CONCLUSIONS: These data show that the extract of P. vulgaris and two polyacetylenic acids possess antifungal and antioomycete activities against a broad spectrum of tested plant pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report on the occurrence of octadeca-9,11,13-triynoic acid and trans-octadec-13-ene-9,11-diynoic acid in P. vulgaris and their efficacy against plant diseases. The crude extract containing the two polyacetylenic acids can be used as a natural fungicide for the control of various plant diseases.


Asunto(s)
Alquinos/farmacología , Antifúngicos/farmacología , Ácidos Grasos Insaturados/farmacología , Extractos Vegetales/farmacología , Prunella/química , Alquinos/análisis , Alquinos/aislamiento & purificación , Antifúngicos/análisis , Antifúngicos/aislamiento & purificación , Ácidos Grasos Insaturados/análisis , Ácidos Grasos Insaturados/aislamiento & purificación , Hongos/efectos de los fármacos , Hongos/crecimiento & desarrollo , Pruebas de Sensibilidad Microbiana , Phytophthora/efectos de los fármacos , Phytophthora/crecimiento & desarrollo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/parasitología , Extractos Vegetales/análisis , Extractos Vegetales/aislamiento & purificación
12.
J Appl Microbiol ; 106(6): 2057-63, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19245403

RESUMEN

AIMS: To characterize antifungal principles from the methanol extract of Magnolia obovata and to evaluate their antifungal activities against various plant pathogenic fungi. METHODS AND RESULTS: Four neolignans were isolated from stem bark of M. obovata as antifungal principles and identified as magnolol, honokiol, 4-methoxyhonokiol and obovatol. In mycelial growth inhibition assay, both magnolol and honokiol displayed more potent antifungal activity than 4-methoxyhonokiol and obovatol. Both magnolol and honokiol showed similar in vivo antifungal spectrum against seven plant diseases tested; both compounds effectively suppressed the development of rice blast, tomato late blight, wheat leaf rust and red pepper anthracnose. 4-Methoxyhonokiol and obovatol were highly active to only rice blast and wheat leaf rust respectively. CONCLUSIONS: The extract of M. obovata and four neolignans had potent in vivo antifungal activities against plant pathogenic fungi. SIGNIFICANCE AND IMPACT OF THE STUDY: Neolignans from Magnolia spp. can be used and suggested as a novel antifungal lead compound for the development of new fungicide and directly as a natural fungicide for the control of plant diseases such as rice blast and wheat leaf rust.


Asunto(s)
Antifúngicos/farmacología , Hongos/efectos de los fármacos , Lignanos/farmacología , Magnolia/química , Extractos Vegetales/farmacología , Compuestos Alílicos , Antifúngicos/química , Antifúngicos/aislamiento & purificación , Compuestos de Bifenilo , Cromatografía en Capa Delgada , Lignanos/química , Lignanos/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Micelio/efectos de los fármacos , Éteres Fenílicos , Corteza de la Planta/química , Enfermedades de las Plantas , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación
13.
J Appl Microbiol ; 106(4): 1213-9, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19120615

RESUMEN

AIMS: To characterize the volatile antifungal compound produced by Oxyporus latemarginatus EF069 and to examine in vitro and in vivo fumigation activity of the fungus. METHODS AND RESULTS: An antifungal volatile-producing strain, O. latemarginatus EF069 inhibited the mycelial growth of Alternaria alternata, Botrytis cinerea, Colletotrichum gloeosporioides, Fusarium oxysporum f. sp. lycopersici, and Rhizoctonia solani by mycofumigation. An antifungal volatile compound was isolated from the hexane extract of wheat bran-rice hull cultures of O. latemarginatus EF069 by repeated silica gel column chromatography and identified as 5-pentyl-2-furaldehyde (PTF). The purified PTF inhibited mycelial growth of R. solani in a dose-dependent manner. The mycofumigation with solid cultures of EF069 also reduced effectively the development of postharvest apple decay caused by B. cinerea and Rhizoctonia root rot of moth orchid caused by R. solani. CONCLUSIONS: Oxyporus latemarginatus EF069 showed in vitro and in vivo fumigation activity against plant pathogenic fungi by producing 5-pentyl-2-furaldehyde. SIGNIFICANCE AND IMPACT OF THE STUDY: Oxyporus latemarginatus EF069 producing an antifungal volatile compound may be used as a biofumigant for the control of fungal plant diseases.


Asunto(s)
Antifúngicos/farmacología , Botrytis/efectos de los fármacos , Hongos/química , Furaldehído/farmacología , Extractos Vegetales/farmacología , Rhizoctonia/efectos de los fármacos , Alternaria/efectos de los fármacos , Antifúngicos/química , Antifúngicos/aislamiento & purificación , Colletotrichum/efectos de los fármacos , Hongos/genética , Furaldehído/aislamiento & purificación , Fusarium/efectos de los fármacos , Malus/efectos de los fármacos , Micelio/efectos de los fármacos , Micelio/crecimiento & desarrollo , Orchidaceae/efectos de los fármacos , Control Biológico de Vectores , Enfermedades de las Plantas/microbiología , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación , Raíces de Plantas/efectos de los fármacos , Reacción en Cadena de la Polimerasa , Análisis de Secuencia de ADN
14.
J Appl Microbiol ; 104(3): 692-8, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17927749

RESUMEN

AIMS: To isolate and identify antioomycete substances from Fusarium oxysporum EF119 against Phytophthora infestans and to investigate their antimicrobial activities against various plant pathogenic bacteria, oomycetes and true fungi. METHODS AND RESULTS: Two antioomycete substances were isolated from liquid cultures of F. oxysporum EF119, which shows a potent disease control efficacy against tomato late blight caused by P. infestans. They were identified as bikaverin and fusaric acid by mass and nuclear magnetic resonance spectral analyses. They inhibited the mycelial growth of plant pathogenic oomycetes and fungi. Fusaric acid also effectively suppressed the cell growth of various plant pathogenic bacteria, but bikaverin was virtually inactive. Treatment with bikaverin at 300 microg ml(-1) suppressed the development of tomato late blight by 71%. Fusaric acid provided effective control against tomato late blight and wheat leaf rust over 67% at concentrations more than 100 microg ml(-1). CONCLUSIONS: Both bikaverin and fusaric acid showed in vitro and in vivo antioomycete activity against P. infestans. SIGNIFICANCE AND IMPACT OF THE STUDY: Fusarium oxysporum EF119 producing both bikaverin and fusaric acid may be used as a biocontrol agent against tomato late blight caused by P. infestans.


Asunto(s)
Microbiología de Alimentos , Fungicidas Industriales/farmacología , Ácido Fusárico/farmacología , Fusarium/química , Phytophthora/efectos de los fármacos , Xantonas/farmacología , Capsicum/microbiología , Ácido Fusárico/química , Extractos Vegetales/farmacología , Xantonas/química
15.
Lett Appl Microbiol ; 44(3): 332-7, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17309513

RESUMEN

AIMS: To isolate endophytic fungi from vegetable plants and examine their in vivo anti-oomycete activity against Phytophthora infestans in tomato plants. METHODS AND RESULTS: Endophytic fungi were isolated from surface-sterilized plant tissues and anti-oomycete activity was measured by in vivo assay using tomato seedlings. Endophytic fungi showing potent anti-oomycete activity were identified by morphological characteristics and nuclear ribosomal ITS1-5.8S-ITS2 sequence analysis. A total of 152 isolates were obtained from 66 healthy tissue samples of cucumber, red pepper, tomato, pumpkin and Chinese cabbage and the fermentation broths of 23 isolates showed potent in vivo anti-oomycete activity against tomato late blight with control values over 90%. The Fusarium oxysporum strain EF119, which was isolated from roots of red pepper, showed the most potent disease control efficacy against tomato late blight. In dual-culture tests, it inhibited the growth of Pythium ultimum, P. infestans and Phytophthora capsici. CONCLUSIONS: Among endophytic fungi isolated from healthy tissues of vegetable plants, F. oxysporum EF119 showed the most potent in vivo anti-oomycete activity against tomato late blight and in vitro anti-oomycete activity against several oomycete pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: Endophytic fungi showing anti-oomycete activity in vitro and in vivo may be used as biocontrol agents particularly of tomato late blight.


Asunto(s)
Productos Agrícolas/microbiología , Hongos/fisiología , Oomicetos/fisiología , Enfermedades de las Plantas/microbiología , Solanum lycopersicum/microbiología , Verduras/microbiología , Hongos/química , Hongos/aislamiento & purificación , Control Biológico de Vectores , Raíces de Plantas/microbiología
16.
J Appl Microbiol ; 99(4): 836-43, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16162234

RESUMEN

AIMS: To investigate the in vitro antifungal and antioomycete activities of some aminoglycosides against true fungi and Phytophthora and Pythium species and to evaluate the potential of the antibiotics against Phytophthora late blight on plants. METHODS AND RESULTS: Antifungal and antioomycete activities of aminoglycoside antibiotics (neomycin, paromomycin, ribostamycin and streptomycin) and a paromomycin-producing strain (Streptomyces sp. AMG-P1) against Phytophthora and Pythium species and 10 common fungi were measured in potato dextrose broth (PDB) and on seedlings in pots. Paromomycin was the most active against Phytophthora and Pythium species with a minimal inhibitory concentration of 1-10 microg ml(-1) in PDB, but displayed low to moderate activities towards other common fungi at the same concentration. Paromomycin also showed potent in vivo activity against red pepper and tomato late blight diseases with 80 and 99% control value, respectively, at 100 microg ml(-1). In addition, culture broth of Streptomyces sp. AMG-P1 as a paromomycin producer exhibited high in vivo activity against late blight at 500 microg freeze-dried weight per millilitre. CONCLUSIONS: Among tested aminoglycoside antibiotics, paromomycin was the most active against oomycetes both in vitro and in vivo. SIGNIFICANCE AND IMPACT OF THE STUDY: Data from this study show that aminoglycoside antibiotics have in vitro and in vivo activities against oomycetes, suggesting that Streptomyces sp. AMG-P1 may be used as a biocontrol agent against oomycete diseases.


Asunto(s)
Antifúngicos/farmacología , Hongos/efectos de los fármacos , Neomicina/farmacología , Phytophthora/efectos de los fármacos , Pythium/efectos de los fármacos , Estreptomicina/farmacología , Capsicum/microbiología , Medios de Cultivo , Solanum lycopersicum/microbiología , Paromomicina/farmacología , Enfermedades de las Plantas/etiología , Enfermedades de las Plantas/microbiología , Ribostamicina/farmacología
17.
Pest Manag Sci ; 57(6): 554-9, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11407033

RESUMEN

Phomalactone, 5,6-dihydro-5-hydroxy-6-prop-2-enyl-2H-pyran-2-one, produced by the fungus Nigrospora sphaerica, was tested in vitro against nine plant pathogenic fungi, and specifically inhibited the mycelial growth of Phytophthora infestans, with an MIC value of 2.5 mg litre-1. Its inhibitory activities against sporangium and zoospore germination of P infestans were similar to those against Phytophthora capsici. In vivo, at 100 and 500 mg litre-1, it reduced the development of tomato late blight caused by P infestans.


Asunto(s)
Ascomicetos/química , Fungicidas Industriales/farmacología , Hongos Mitospóricos/efectos de los fármacos , Oomicetos/efectos de los fármacos , Enfermedades de las Plantas/microbiología , Pironas/farmacología , Ascomicetos/aislamiento & purificación , Fungicidas Industriales/química , Fungicidas Industriales/aislamiento & purificación , Concentración 50 Inhibidora , Pruebas de Sensibilidad Microbiana , Hongos Mitospóricos/clasificación , Oomicetos/clasificación , Pironas/química , Pironas/aislamiento & purificación , Especificidad de la Especie , Espectrofotometría Ultravioleta
18.
Pest Manag Sci ; 57(6): 564-9, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11407035

RESUMEN

In order to develop a new method for measuring foliar uptake of fungicides, Congo Red was selected as a tracer, and optimum procedures were established for washing, extracting and analyzing it and fungicides from leaf surfaces. Congo Red, a water-soluble dye, was not absorbed into cucumber or rice leaf, even in the presence of various surfactants, and was completely washable from leaf surfaces by aqueous acetonitrile solutions. Congo Red and fungicides in washings were quantified to calculate the amount of foliar uptake of the latter, by comparing the ratio to Congo Red. The optimum concentration of Congo Red in a formulation should be established in order to minimize its influence on fungicide uptake. Although Congo Red has proved to be useful with a conventional droplet application method, it will give more realistic and practical results with the spraying method used in the present study.


Asunto(s)
Colorantes/metabolismo , Rojo Congo/metabolismo , Cucurbitaceae/metabolismo , Fungicidas Industriales/metabolismo , Oryza/metabolismo , Acetonitrilos/farmacología , Algoritmos , Rojo Congo/química , Fungicidas Industriales/química , Modelos Biológicos , Hojas de la Planta/metabolismo , Oligoelementos , Agua/metabolismo
19.
J Korean Med Sci ; 5(1): 53-8, 1990 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-2206467

RESUMEN

We experienced a case of chronic fibrosing pancreatitis in an 18/12-year-old girl, which was idiopathic because there were no familial back ground, no cystic fibrosis of pancrease, no ductal anomalies and obstruction. The patient presented intermittent colicky abdominal pain and progressive obstructive jaundice, but T-tube drainage and removal of the lymph nodes around the common bile duct relieved her symptoms and disease process. This seems to be the first case reported in a Korean child. Idiopathic fibrosing pancreatitis should be considered in the differential diagnosis of abdominal pain with obstructive jaundice in children.


Asunto(s)
Pancreatitis/patología , Dolor Abdominal/complicaciones , Femenino , Fibrosis , Humanos , Lactante , Ictericia Idiopática Crónica/complicaciones , Pancreatitis/complicaciones
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