Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Gut Liver ; 14(4): 450-458, 2020 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-32000467

RESUMEN

Background/Aims: Several clinical factors have been used to predict the response for concurrent chemoradiotherapy (CCRT); however, these factors are insufficient for prognostic predictions. We investigated clinical factors to assess whether they could be used to predict the response to CCRT and the survival of patients with esophageal cancer. Methods: Patients with esophageal cancer underwent CCRT from January 2005 to December 2015. Response to CCRT was classified as progressive disease (PD), stationary disease (SD), partial remission (PR), or complete remission (CR). Factors to predict the response to CCRT and patient survival were subsequently investigated. Results: A total of 535 esophageal cancer patients underwent CCRT. Four hundred ninety-three patients were followed up, and patient outcomes were investigated. In the adjusted analysis, patients with advanced stage disease (relative risk [RR], 0.28 in stage III and 0.12 in stage IV compared to stage I), poor performance status, circumferential involvement (RR, 0.61), and male sex (RR, 0.31) were less likely to achieve CR. Advanced stage disease (hazard ratio [HR], 1.71 in stage III/IV), poor CCRT response (HR, 2.82 in PR, 4.47 in SD, 4.77 in PD compared to CR), and poor performance status (HR, 1.38 in ECOG 2-4) were found to increase mortality. Conclusions: Advanced stage disease, poor performance status, male sex, and circumferential involvement were independent predictive factors for a poor response to CCRT. Advanced stage, poor performance status, and poor CCRT response were independent factors for decreased survival.


Asunto(s)
Quimioradioterapia , Neoplasias Esofágicas , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica , Neoplasias Esofágicas/patología , Neoplasias Esofágicas/terapia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Pronóstico , Modelos de Riesgos Proporcionales
2.
Korean J Intern Med ; 34(6): 1215-1222, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30257552

RESUMEN

BACKGROUND/AIMS: The Internet is the main resource for health-related information. The incidence of inflammatory bowel disease (IBD) is rapidly increasing in Asian countries. However, the quality of websites for IBD available in this region has not been evaluated. We aimed to evaluate the quality of the information on IBD obtained from Korean websites. METHODS: Using the terms "Crohn's disease" or "ulcerative colitis," websites were selected from those obtained with the three most renowned search engines in Korea; 60 websites from the results of each engine were chosen. The websites were classified into institutional, commercial, charitable, supportive, or alternative medicine types according to the characteristics of each site. The websites were evaluated regarding content quality using the validated DISCERN instrument and the Journal of the American Medical Association benchmarks. RESULTS: The median score of all the websites according to the DISCERN instrument was 32 (interquartile range, 25 to 47) out of 80, indicating an insufficient overall quality of information. The alternative medicine sites scored the lowest, whereas the institutional sites scored the highest (p < 0.05). The quality of information was significantly different among the search engines (p = 0.028). The rank of appearance in the Google search result did not correlate with the quality level of the information. CONCLUSION: The quality of information on the Internet regarding IBD varied according to the website type and search engine. Accreditation and quality assurance systems should be implemented for websites to ensure that the public and patients obtain accurate information on IBD.


Asunto(s)
Acceso a la Información , Colitis Ulcerosa , Información de Salud al Consumidor , Enfermedad de Crohn , Conducta en la Búsqueda de Información , Internet , Motor de Búsqueda , Colitis Ulcerosa/diagnóstico , Colitis Ulcerosa/fisiopatología , Colitis Ulcerosa/terapia , Comprensión , Enfermedad de Crohn/diagnóstico , Enfermedad de Crohn/fisiopatología , Enfermedad de Crohn/terapia , Conocimientos, Actitudes y Práctica en Salud , Alfabetización en Salud , Humanos , Educación del Paciente como Asunto , República de Corea
3.
J Korean Med Sci ; 33(23): e166, 2018 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-29853821

RESUMEN

BACKGROUND: The optimal endoscopic screening interval for early gastric cancer (EGC) detection still remains controversial. Thus, we performed this prospective study to clarify the optimal interval between endoscopic examinations for EGC detection. METHODS: A questionnaire survey for penultimate endoscopy and gastric cancer (GC) diagnosis interval was used; the findings were then analyzed. The patients were divided into two groups according to GC type and endoscopic examinations intervals. RESULTS: A total of 843 patients were enrolled. The endoscopic GC detection interval (P < 0.001), tumor location (P < 0.001), tumor size (P < 0.001), histology (P < 0.001), tumor stage (P < 0.001), and treatment modality (P < 0.001) showed significant differences in the univariate analysis between EGC and advanced gastric cancer (AGC). Endoscopic examination intervals below 2 years and 3 years were associated with higher proportions of EGC detection (adjusted odds ratio, 2.458 and 3.022, respectively) (P < 0.001). The patients with endoscopic examination to GC diagnosis interval of < 2 years showed significant differences in tumor size (P < 0.001), tumor stage (P < 0.001), and treatment modality (P < 0.001) compared to those with intervals of > 2 years and without screening. Similar results were observed in those with < 3-year intervals. CONCLUSION: Triennial endoscopic screening might be as effective as biennial screening in increasing the detection rate of EGC and the risk of subsequent curable endoscopic resections.


Asunto(s)
Neoplasias Gástricas/diagnóstico , Anciano , Antineoplásicos/uso terapéutico , Detección Precoz del Cáncer , Femenino , Gastroscopía , Humanos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Oportunidad Relativa , Estudios Prospectivos , Estómago/patología , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/patología , Neoplasias Gástricas/cirugía , Factores de Tiempo
4.
J Exerc Nutrition Biochem ; 20(3): 51-55, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27757388

RESUMEN

PURPOSE: The purpose of the current study was to investigate steps per day (steps/d) and physical activity level (PAL) in Korean elementary school children having normal weight (normal-weight). We also clarified whether a gender difference exited between steps/d and PAL. METHODS: Children aged 9 to 12 y were recruited from two elementary schools located in different urban districts in Korea. The present study included 33 Korean children, of which 18 were normal-weight boys and 15 were normal-weight girls. During the same 1 week study period under free-living conditions the total energy expenditure (TEE) and step counts were estimated using the doubly labeled water (DLW) method and an accelerometer, respectively. We calculated PAL as the TEE/ resting metabolic rate. RESULTS: The range of PAL was 1.25 - 1.93 with a mean value of 1.57. None of the variables of energy expenditure was significantly different by sex. However, steps/d were significantly higher in boys than in girls. When adjusting regression analysis by gender, steps/ d were positively associated with PAL among all subjects (r = 0.56, P < 0.01). Furthermore, steps/d were positively associated with PAL in boys (r = 0.68, P < 0.01), but not in girls (r = 0.27, P = 0.34). CONCLUSION: Our results suggest that locomotive activity may be the main contributor to the individual PAL differences for elementary school boys, while non-locomotive activity may be the main contributor for elementary school girls.

5.
Mol Plant Pathol ; 17(1): 29-41, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25845484

RESUMEN

Hemibiotrophic plant pathogens, such as the oomycete Phytophthora infestans, employ a biphasic infection strategy, initially behaving as biotrophs, where minimal symptoms are exhibited by the plant, and subsequently as necrotrophs, feeding on dead plant tissue. The regulation of this transition and the breadth of molecular mechanisms that modulate plant defences are not well understood, although effector proteins secreted by the pathogen are thought to play a key role. We examined the transcriptional dynamics of P. infestans in a compatible interaction with its host tomato (Solanum lycopersicum) at three infection stages: biotrophy; the transition from biotrophy to necrotrophy; and necrotrophy. The expression data suggest a tight temporal regulation of many pathways associated with the suppression of plant defence mechanisms and pathogenicity, including the induction of putative cytoplasmic and apoplastic effectors. Twelve of these were experimentally evaluated to determine their ability to suppress necrosis caused by the P. infestans necrosis-inducing protein PiNPP1.1 in Nicotiana benthamiana. Four effectors suppressed necrosis, suggesting that they might prolong the biotrophic phase. This study suggests that a complex regulation of effector expression modulates the outcome of the interaction.


Asunto(s)
Phytophthora infestans/genética , Phytophthora infestans/patogenicidad , Enfermedades de las Plantas/microbiología , Solanum lycopersicum/microbiología , Transcripción Genética , Análisis por Conglomerados , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Hojas de la Planta/microbiología , Proteínas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Análisis de Secuencia de ADN , Factores de Tiempo , Nicotiana/microbiología , Transcriptoma/genética
6.
Biochem Biophys Res Commun ; 446(4): 882-8, 2014 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-24631906

RESUMEN

Plant cells secrete diverse sets of constitutively- and conditionally-expressed proteins under various environmental and developmental states. Secreted protein populations, or secretomes have multiple functions, including defense responses, signaling, metabolic processes, and developmental regulation. To identify genes encoding secreted proteins that function in fruit development and ripening, a yeast secretion trap (YST) screen was employed using pepper (Capsicum annuum) fruit cDNAs. The YST screen revealed 80 pepper fruit-related genes (CaPFRs) encoding secreted proteins including cell wall proteins, several of which have not been previously described. Transient GFP-fusion assay and an in planta secretion trap were used to validate the secretion of proteins encoded by selected YST clones. In addition, RNA gel blot analyses provided further insights into their expression and regulation during fruit development and ripening. Integrating our data, we conclude that the YST provides a valuable functional genomics tool for the identification of substantial numbers of novel secreted plant proteins that are associated with biological processes, including fruit development and ripening.


Asunto(s)
Capsicum/crecimiento & desarrollo , Frutas/crecimiento & desarrollo , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Capsicum/genética , ADN Complementario/genética , Frutas/genética , Regulación del Desarrollo de la Expresión Génica , Biblioteca de Genes , Genes de Plantas , Proteínas de Plantas/metabolismo , Saccharomyces cerevisiae/genética
7.
Korean J Gastroenterol ; 59(3): 232-8, 2012 Mar.
Artículo en Coreano | MEDLINE | ID: mdl-22460572

RESUMEN

BACKGROUND/AIMS: ERCP is the most common procedure for the diagnosis and treatment of bile duct and pancreatic disease, but Post-ERCP pancreatitis makes poor outcome in some cases. The protease inhibitors, nafamostat and gabexate, have been used to prevent pancreatitis related to ERCP, but there is some debate. We tried to evaluate the efficacy of gabexate and nafamostat for the prevention of post-ERCP pancreatitis. METHODS: Two hundred forty two patients (73 patients in the gabexate group, 88 patients in the nafamostat group and 81 patients in the placebo group) were included in the study after selective exclusion. The incidence of pancreatitis after ERCP was compared among groups. RESULTS: The incidence of pancreatitis were 6.8% in the gabexate group, 5.7% in the nafamostat group and 6.2% in the placebo group (p=0.954). CONCLUSIONS: There was no meaningful difference among the gabexate, nafamostat and placebo group.


Asunto(s)
Colangiopancreatografia Retrógrada Endoscópica/efectos adversos , Gabexato/uso terapéutico , Guanidinas/uso terapéutico , Pancreatitis/prevención & control , Inhibidores de Serina Proteinasa/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Benzamidinas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pancreatitis/etiología , Efecto Placebo , Encuestas y Cuestionarios , Adulto Joven
8.
Proc Natl Acad Sci U S A ; 109(11): 4197-202, 2012 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-22371593

RESUMEN

Horizontal gene transfer (HGT) involves the nonsexual transmission of genetic material across species boundaries. Although often detected in prokaryotes, examples of HGT involving animals are relatively rare, and any evolutionary advantage conferred to the recipient is typically obscure. We identified a gene (HhMAN1) from the coffee berry borer beetle, Hypothenemus hampei, a devastating pest of coffee, which shows clear evidence of HGT from bacteria. HhMAN1 encodes a mannanase, representing a class of glycosyl hydrolases that has not previously been reported in insects. Recombinant HhMAN1 protein hydrolyzes coffee berry galactomannan, the major storage polysaccharide in this species and the presumed food of H. hampei. HhMAN1 was found to be widespread in a broad biogeographic survey of H. hampei accessions, indicating that the HGT event occurred before radiation of the insect from West Africa to Asia and South America. However, the gene was not detected in the closely related species H. obscurus (the tropical nut borer or "false berry borer"), which does not colonize coffee beans. Thus, HGT of HhMAN1 from bacteria represents a likely adaptation to a specific ecological niche and may have been promoted by intensive agricultural practices.


Asunto(s)
Adaptación Biológica/genética , Coffea/parasitología , Escarabajos/genética , Transferencia de Gen Horizontal/genética , Genes Bacterianos/genética , Especies Introducidas , Animales , ADN/genética , Células Eucariotas/metabolismo , Frutas/parasitología , Galactosa/análogos & derivados , Tracto Gastrointestinal/enzimología , Genes de Insecto/genética , Geografía , Hidrólisis , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Mananos/metabolismo , Manosidasas/metabolismo , Datos de Secuencia Molecular , Mutagénesis Insercional , Filogenia , Proteínas Recombinantes/metabolismo
9.
Methods Mol Biol ; 835: 519-30, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22183675

RESUMEN

Secreted proteins from plants and phytopathogens play important roles in their interactions and contribute to elaborate mechanisms of attack, defense, and counter-defense, as well as surveillance and signaling. There is therefore considerable interest in developing techniques to characterize "secretomes." Here, we describe the use of the yeast secretion trap (YST) functional screen to isolate and identify secreted proteins that are accumulated and detected in the extracellular matrix of eukaryotes. This method involves fusing cDNAs generated or derived from plants, pathogens, or infected tissue to a yeast (Saccharomyces cerevisiae) invertase (suc2) reporter gene lacking its signal peptide, transforming the resulting fusion library into an invertase-deficient yeast strain, and plating the transformants on a sucrose selection medium. A yeast transformant containing a cDNA that encodes a secreted protein can rescue the mutant and the plasmid DNA can then be sequenced to identify the secreted protein. The YST screen can be a very powerful tool in the study of dynamics of plant host-pathogen interactions.


Asunto(s)
Interacciones Huésped-Patógeno , Plantas/microbiología , Proteínas/metabolismo , Saccharomyces cerevisiae/metabolismo , Pared Celular/metabolismo , Pared Celular/microbiología , ADN Complementario/genética , Plantas/genética , Plantas/metabolismo , Proteínas/genética , Saccharomyces cerevisiae/enzimología , Saccharomyces cerevisiae/genética , Transformación Genética , beta-Fructofuranosidasa/genética , beta-Fructofuranosidasa/metabolismo
10.
Korean J Gastroenterol ; 58(5): 270-4, 2011 Nov 25.
Artículo en Coreano | MEDLINE | ID: mdl-22113044

RESUMEN

Hepatocellular carcinoma (HCC) is one of the most common malignant neoplasms occuring worldwide. Although surgical resection still remains the treatment of choice for HCC, radiofrequency ablation (RFA) has emerged as reliable alternatives to resection. It is less invasive and can be repeated after short intervals for sequential ablation in case of multiple lesions. The most common complication of RFA is liver abscess, and bile duct injury such as bile duct stricture has been reported. This is a case report of a rare complication of abscesso-colonic fistula after RFA for HCC. The case was treated by percutaneous abscess drainage and antibiotics and occlusion of abscesso-colonic fistula with n-butyl-2-cyanoacrylate embolization.


Asunto(s)
Carcinoma Hepatocelular/cirugía , Ablación por Catéter/efectos adversos , Enfermedades del Colon/terapia , Enbucrilato/uso terapéutico , Fístula Intestinal/terapia , Neoplasias Hepáticas/cirugía , Anciano , Antibacterianos/uso terapéutico , Carcinoma Hepatocelular/diagnóstico , Enfermedades del Colon/etiología , Drenaje , Embolización Terapéutica , Humanos , Fístula Intestinal/etiología , Absceso Hepático/diagnóstico por imagen , Absceso Hepático/etiología , Neoplasias Hepáticas/diagnóstico , Masculino , Pseudomonas aeruginosa/aislamiento & purificación , Tomografía Computarizada por Rayos X , Ultrasonografía
11.
Korean J Hepatol ; 17(2): 148-51, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21757986

RESUMEN

Radiofrequency ablation (RFA) is performed as an alternative to surgical resection for primary or secondary liver malignancies. Although RFA can be performed safely in most patients, early and late complications related to mechanical or thermal damage occur in 8-9.5% cases. Hemocholecyst, which refers to hemorrhage of the gallbladder, has been reported with primary gallbladder disease or as a secondary event associated with hemobilia. Hemobilia, defined as hemorrhage in the biliary tract and most commonly associated with accidental or iatrogenic trauma, is a rare complication of RFA. Here we report a case of hemocholecyst associated with hemobilia after RFA for hepatocellular carcinoma that was successfully managed by laparoscopic cholecystectomy.


Asunto(s)
Carcinoma Hepatocelular/cirugía , Ablación por Catéter/efectos adversos , Enfermedades de la Vesícula Biliar/etiología , Hemobilia/etiología , Hemorragia/etiología , Neoplasias Hepáticas/cirugía , Anciano , Colangiopancreatografia Retrógrada Endoscópica , Colecistectomía , Enfermedades de la Vesícula Biliar/diagnóstico por imagen , Enfermedades de la Vesícula Biliar/cirugía , Hemobilia/diagnóstico , Hemobilia/cirugía , Humanos , Masculino , Tomografía Computarizada por Rayos X , Ultrasonografía
12.
Mol Plant Microbe Interact ; 24(6): 671-84, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21542767

RESUMEN

In plants, the primary defense against pathogens is mostly inducible and associated with cell wall modification and defense-related gene expression, including many secreted proteins. To study the role of secreted proteins, a yeast-based signal-sequence trap screening was conducted with the RNA from Phytophthora capsici-inoculated root of Capsicum annuum 'Criollo de Morelos 334' (CM334). In total, 101 Capsicum annuum secretome (CaS) clones were isolated and identified, of which 92 were predicted to have a secretory signal sequence at their N-terminus. To identify differences in expressed CaS genes between resistant and susceptible cultivars of pepper, reverse Northern blots and real-time reverse-transcription polymerase chain reaction were performed with RNA samples isolated at different time points following P. capsici inoculation. In an attempt to assign biological functions to CaS genes, we performed in planta knock-down assays using the Tobacco rattle virus-based gene-silencing method. Silencing of eight CaS genes in pepper resulted in suppression of the cell death induced by the non-host bacterial pathogen (Pseudomonas syringae pv. tomato T1). Three CaS genes induced phenotypic abnormalities in silenced plants and one, CaS259 (PR4-l), caused both cell death suppression and perturbed phenotypes. These results provide evidence that the CaS genes may play important roles in pathogen defense as well as developmental processes.


Asunto(s)
Capsicum/metabolismo , Capsicum/microbiología , Muerte Celular/fisiología , Phytophthora/fisiología , Enfermedades de las Plantas/microbiología , Proteínas de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas/fisiología , Silenciador del Gen , Interacciones Huésped-Patógeno , Proteínas de Plantas/genética
13.
Methods Mol Biol ; 715: 255-72, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21222090

RESUMEN

Plant cell wall proteins play essential roles in many important biological processes, and yet there is still not a comprehensive catalogue of the cell wall proteome, or "secretome". Here, we describe three procedures, including a yeast secretion trap (YST), Agrobacterium-mediated transient expression using a necrosis-inducing protein (NIP) and protein localization assay using a fluorescent protein, to identify and confirm the localization of cell wall proteins. The approaches are orthogonal and collectively provide a powerful suite of approaches to complement more commonly used strategies to isolate plant cell wall-associated proteins.


Asunto(s)
Pared Celular/química , Proteínas de Plantas/química , Proteoma/química , Agrobacterium tumefaciens/genética , Biolística , Biblioteca de Genes , Vectores Genéticos , Ensayos Analíticos de Alto Rendimiento , Microscopía Confocal , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Proteínas de Plantas/biosíntesis , Proteínas de Plantas/genética , Proteínas Recombinantes de Fusión/biosíntesis , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Saccharomyces cerevisiae/genética , Nicotiana/genética , Nicotiana/metabolismo , Transfección
14.
J Adv Prosthodont ; 3(4): 177-85, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22259700

RESUMEN

PURPOSE: The aim of this study was to evaluate the effect of dimensional stability of splinting material on the accuracy of master casts. MATERIALS AND METHODS: A stainless steel metal model with 6 implants embedded was used as a master model. Implant level impressions were made after square impression copings were splinted using 5 different techniques as follows. (1) Splinted with autopolymerizing resin and sectioned, reconnected to compensate polymerization shrinkage before the impression procedure. (2) Splinted with autopolymerizing resin just before impression procedure. (3) Primary impression made with impression plaster and secondary impression were made over with polyether impression material. (4) Splinted with impression plaster. (5) Splinted with VPS bite registration material. From master model, 5 impressions and 5 experimental casts, total 25 casts were made for each of 5 splinting methods. The distortion values of each splinting methods were measured using coordinate measuring machine, capable of recordings in the x-, y-, z-axes. A one-way analysis of variance (ANOVA) at a confidence level of 95% was used to evaluate the data and Tukey's studentized range test was used to determine significant differences between the groups. RESULTS: Group 1 showed best accuracy followed by Group 3 & 4. Group 2 and 5 showed relatively larger distortion value than other groups. No significant difference was found between group 3, 4, 5 in x-axis, group 2, 3, 4 in y-axis and group 1, 3, 4, 5 in z-axis (P<.0001). CONCLUSION: Both Splinting impression copings with autopolymerizing resin following compensation of polymerization shrinkage and splinting method with impression plaster can enhance the accuracy of master cast and impression plaster can be used simple and effective splinting material for implant impression procedure.

15.
Plant Signal Behav ; 5(6): 769-72, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20400849

RESUMEN

Hemibiotrophs, such as Phytophthora infestans, exhibit distinct phases of their life cycle: an early asymptomatic biotrophic phase and a late necrotrophic stage that is characterized by tissue degradation and disease symptoms. To date, little is known of the molecular mechanisms that promote each distinct phase, nor those that mediate the transition between the two. We hypothesized that these phytopathogens might secrete distinct classes of effector proteins that first suppress plant defense responses and associated programmed cell death (PCD), and later induce large scale necrosis. To this end, we have identified proteins that are secreted by P. infestans early or late in the infection cycle. Recently we described the characterization of SNE1, which is specifically expressed during early biotrophic growth in the host plant tomato (Solanum lycopersicum). We found that SNE1 suppresses the action of necrosis-inducing effectors (Nep1-like proteins), including PiNPP1.1 and PsojNIP, which are secreted by Phytophthora during necrotrophic growth, as well as PCD mediated by a broad spectrum of Avr-R protein interactions. This suggests that SNE1 and PiNPP1.1 act antagonistically, thereby providing a highly regulated means to control the transition from biotrophy to necrotrophy.

17.
Plant J ; 62(3): 357-66, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20128886

RESUMEN

Evasion or active suppression of host defenses are critical strategies employed by biotrophic phytopathogens and hemibiotrophs whose infection mechanism includes sequential biotrophic and necrotrophic stages. Although defense suppression by secreted effector proteins has been well studied in bacteria, equivalent systems in fungi and oomycetes are poorly understood. We report the characterization of SNE1 (suppressor of necrosis 1), a gene encoding a secreted protein from the hemibiotrophic oomycete Phytophthora infestans that is specifically expressed at the transcriptional level during biotrophic growth within the host plant tomato (Solanum lycopersicum). Using transient expression assays, we show that SNE1 suppresses the action of secreted cell death-inducing effectors from Phytophthora that are expressed during the necrotrophic growth phase, as well as programmed cell death mediated by a range of Avr-R protein interactions. We also report that SNE1 contains predicted NLS motifs and translocates to the plant nucleus in transient expression studies. A conceptual model is presented in which the sequential coordinated secretion of antagonistic effectors by P. infestans first suppresses, but then induces, host cell death, thereby providing a highly regulated means to control the transition from biotrophy to necrotrophy.


Asunto(s)
Proteínas Algáceas/metabolismo , Apoptosis , Phytophthora infestans/crecimiento & desarrollo , Solanum lycopersicum/parasitología , Proteínas Algáceas/genética , Secuencia de Aminoácidos , Clonación Molecular , ADN de Algas/genética , ADN de Plantas/genética , Regulación de la Expresión Génica de las Plantas , Solanum lycopersicum/genética , Datos de Secuencia Molecular , Phytophthora infestans/genética , Phytophthora infestans/patogenicidad , Análisis de Secuencia de ADN
18.
Mol Plant Microbe Interact ; 19(12): 1368-77, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17153921

RESUMEN

Complex suites of proteins that are secreted by plants and phytopathogens into the plant apoplast play crucial roles in surveillance, assault, defense, and counter-defense. High-throughput genome-scale strategies are being developed to better understand the nature of these "secretomes" and the identity of pathogen-derived effector proteins that subvert plant defenses and promote pathogenicity. Although combined bioinformatic and experimental approaches recently have provided comprehensive coverage of secreted proteins from bacterial phytopathogens, far less is known about the secretomes and batteries of effectors of eukaryotic phytopathogens; notably fungi and oomycetes. The yeast secretion trap (YST) represents a potentially valuable technique to simultaneously target pathogen and host secretomes in infected plant material. A YST screen, using a new vector system, was applied to study the interaction between tomato (Solanum lycopersicum) and the oomycete Phytophthora infestans, revealing sets of genes encoding secreted proteins from both pathogen and host. Most of those from the oomycete had no identifiable function and were detectable in planta only during pathogenesis, underlining the value of YST as a tool to identify new candidate effectors and pathogenicity factors. In addition, the majority of the P. infestans proteins had homologs in the genomes of the related oomycetes R. sojae and P. ramorum.


Asunto(s)
Proteínas Algáceas/metabolismo , Phytophthora/patogenicidad , Proteínas de Plantas/metabolismo , Solanum lycopersicum/parasitología , Proteínas Algáceas/química , Proteínas Algáceas/genética , Secuencia de Aminoácidos , Vectores Genéticos , Genoma , Biblioteca Genómica , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Datos de Secuencia Molecular , Phytophthora/genética , Phytophthora/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/parasitología , Proteínas de Plantas/química , Proteínas de Plantas/genética , Saccharomyces cerevisiae/genética , Alineación de Secuencia
19.
Nat Protoc ; 1(5): 2439-47, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-17406489

RESUMEN

Secreted and cell surface proteins play essential roles in numerous essential biological processes in eukaryotic organisms, but are often more difficult to isolate and identify than proteins that are localized in intracellular compartments. However, several high-throughput 'gene-trap' techniques have been developed to characterize these 'secretomes', including the yeast secretion trap (YST) screen. This method involves fusing cDNA libraries from the tissue or cell type of interest to a yeast (Saccharomyces cerevisiae) invertase reporter gene, transforming the resulting fusion library into an invertase-deficient yeast strain and plating the transformants on a medium containing sucrose as the sole carbon source. A yeast cell with a transgene encoding a secreted or cell surface protein can synthesize a secreted invertase fusion protein that can rescue the mutant, and the plasmid DNA can then be sequenced to identify the gene that encodes it. We describe a recently improved version of this screen, which allows the identification of genes encoding secreted proteins in 1-2 months.


Asunto(s)
Células Eucariotas/metabolismo , Técnicas de Transferencia de Gen , Proteínas de la Membrana/análisis , Proteómica/métodos , Saccharomyces cerevisiae/genética , Escherichia coli/genética , Biblioteca de Genes , Genes Reporteros , Proteínas de la Membrana/genética , beta-Fructofuranosidasa/genética
20.
J Exp Bot ; 56(418): 2229-38, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15983008

RESUMEN

Many developmental processes and induced plant responses have been identified that are directly or indirectly influenced by wall-localized, or apoplastic, molecular interactions and signalling pathways. The yeast-based signal sequence trap (YSST) is a potentially valuable experimental tool to characterize the proteome of the wall and apoplast, or 'secretome', although few studies have been performed with plants and to date this strategy has not been coupled with a subsequent analysis to confirm extracellular localization of candidate proteins in planta. This current report describes the use of the YSST, together with transient expression of a selection of identified proteins as fusions with the reporter GFP, focusing on the complex extracellular interactions between peach (Prunus persica) pollen and pistil tissues. The coupled YSST and GFP localization assay was also used to confirm the extracellular localization of a recently identified pistil-specific basic RNase protein (PA1), as has been observed with S-RNases that are involved in self-incompatibility. This pilot YSST screen of pollinated and unpollinated pistil cDNAs revealed a diverse set of predicted cell wall-localized or plasma membrane-bound proteins, several of which have not previously been described. Transient GFP-fusion assays and RNA gel blot analyses were used to confirm their subcellular localization and to provide further insights into their expression or regulation, respectively. These results demonstrated that the YSST strategy represents an effective means either to confirm the extracellular localization of a specific candidate secreted protein, as demonstrated here with PA1, or to conduct a screen for new extracellular proteins.


Asunto(s)
Flores/metabolismo , Perfilación de la Expresión Génica/métodos , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Prunus/genética , Prunus/metabolismo , Genes de Plantas , Organismos Modificados Genéticamente , Proteínas de Plantas/metabolismo , Señales de Clasificación de Proteína , Ribonucleasas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...