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1.
Gynecol Obstet Fertil Senol ; 46(10-11): 686-691, 2018 11.
Artículo en Francés | MEDLINE | ID: mdl-30293947

RESUMEN

OBJECTIVES: Operative Vaginal Delivery (OVD) is subject to a risk of perineal tears especially of Obstetrical Anal Sphincter Injuries (OASIS) that are associated with more complications and impaired quality of life. The main objective of this study was to compare the rate of OASIS in primipara at term with fetus in cephalic presentation depending on the type of delivery: OVD using vacuum extractor and spontaneous delivery. METHODS: This is a single-center retrospective study between 01/01/2010 and 12/31/2014 including all primipara who delivered vaginally at term, a single and living fetus in cephalic presentation. Perineal lesions were classified according to the WHO classification. The primary endpoint was the proportion of OASIS. RESULTS: 3552 patients were included: 2496 spontaneous deliveries (SD) and 1056 OVD (29.72 %). There were twenty sphincter tears (0.56 %): 7 in SD group (0.28 %) and 13 in OVD (1.23 %), P<0.0001, OR=5.10 [2.00; 12.99]. Other risk factors associated with OASIS in univariable analysis were: maternal age (≥30 years), duration of expulsive efforts (≥20min) and a birth weight≥4000g. CONCLUSION: In these patients, the risk of OASIS in case of AI increases by a factor of 5;10. The high rate of AI in these patients exposes them to a real risk of OASIS. However, the proportion of OASIS in this group remains lower than those reported in the literature and is barely higher than the national overall rate, despite a very restrictive policy of the use of episiotomy.


Asunto(s)
Canal Anal/lesiones , Paridad , Extracción Obstétrica por Aspiración/efectos adversos , Adulto , Parto Obstétrico/métodos , Femenino , Humanos , Laceraciones/epidemiología , Embarazo , Estudios Retrospectivos , Factores de Riesgo , Nacimiento a Término
2.
Neurología (Barc., Ed. impr.) ; 32(4): 241-252, mayo 2017. tab, ilus
Artículo en Español | IBECS | ID: ibc-162029

RESUMEN

Introducción. El síndrome X frágil (SXF) es la causa más frecuente de discapacidad intelectual hereditaria y se asocia a un amplio espectro de enfermedades en las distintas generaciones de una misma familia. En este trabajo se revisan las manifestaciones clínicas de los trastornos asociados al X frágil y el espectro de mutaciones en el gen 1 del retraso mental del X frágil (FMR1), la neurobiología de la proteína del retardo mental X frágil (FMRP) y una visión general de los potenciales blancos terapéuticos y el asesoramiento genético. Desarrollo. Esta enfermedad es causada por una amplificación de las repeticiones CGG (>200 repeticiones) en la región 5’ no traducida del gen FMR1, que lleva al déficit o ausencia de la proteína FMRP. La FMRP es una proteína de unión al ARN que regula la traducción de varios genes que son importantes en la plasticidad sináptica y la maduración dendrítica. Se cree que expansiones de las repeticiones CGG en el rango de premutación (55-200 repeticiones) generan un aumento en los niveles de mRNA de FMR1, lo que produciría toxicidad neuronal. Esto se manifiesta en problemas del desarrollo tales como autismo y problemas de aprendizaje, así como en patologías neurodegenerativas como el síndrome de temblor/ataxia asociado al X frágil (FXTAS). Conclusiones. Los avances en la identificación de las bases moleculares del SXF pueden servir como modelo para comprender las causas de las enfermedades neuropsiquiátricas y probablemente conducirán al desarrollo de tratamientos cada vez más específicos (AU)


Background. Fragile X syndrome, the most common inherited cause of intellectual disability, is associated with a broad spectrum of disorders across different generations of a single family. This study reviews the clinical manifestations of fragile X-associated disorders as well as the spectrum of mutations of the fragile X mental retardation 1 gene (FMR1) and the neurobiology of the fragile X mental retardation protein (FMRP), and also provides an overview of the potential therapeutic targets and genetic counselling. Development. This disorder is caused by expansion of the CGG repeat (>200 repeats) in the 5 prime untranslated region of FMR1, resulting in a deficit or absence of FMRP. FMRP is an RNA-binding protein that regulates the translation of several genes that are important in synaptic plasticity and dendritic maturation. It is believed that CGG repeat expansions in the premutation range (55 to 200 repeats) elicit an increase in mRNA levels of FMR1, which may cause neuronal toxicity. These changes manifest clinically as developmental problems such as autism and learning disabilities as well as neurodegenerative diseases including fragile X-associated tremor/ataxia syndrome (FXTAS). Conclusions. Advances in identifying the molecular basis of fragile X syndrome may help us understand the causes of neuropsychiatric disorders, and they will probably contribute to development of new and specific treatments (AU)


Asunto(s)
Humanos , Masculino , Femenino , Discapacidad Intelectual Ligada al Cromosoma X/diagnóstico , Discapacidad Intelectual Ligada al Cromosoma X/tratamiento farmacológico , Discapacidad Intelectual/genética , Trastorno Autístico/genética , Metilación de ADN/genética , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/análisis , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/administración & dosificación , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/genética , Neurobiología/métodos , Discapacidad Intelectual/diagnóstico , Trastorno Autístico/complicaciones , Neuropatología/métodos
3.
Neurologia ; 32(4): 241-252, 2017 May.
Artículo en Inglés, Español | MEDLINE | ID: mdl-25529181

RESUMEN

BACKGROUND: Fragile X syndrome, the most common inherited cause of intellectual disability, is associated with a broad spectrum of disorders across different generations of a single family. This study reviews the clinical manifestations of fragile X-associated disorders as well as the spectrum of mutations of the fragile X mental retardation 1 gene (FMR1) and the neurobiology of the fragile X mental retardation protein (FMRP), and also provides an overview of the potential therapeutic targets and genetic counselling. DEVELOPMENT: This disorder is caused by expansion of the CGG repeat (>200 repeats) in the 5 prime untranslated region of FMR1, resulting in a deficit or absence of FMRP. FMRP is an RNA-binding protein that regulates the translation of several genes that are important in synaptic plasticity and dendritic maturation. It is believed that CGG repeat expansions in the premutation range (55 to 200 repeats) elicit an increase in mRNA levels of FMR1, which may cause neuronal toxicity. These changes manifest clinically as developmental problems such as autism and learning disabilities as well as neurodegenerative diseases including fragile X-associated tremor/ataxia syndrome (FXTAS). CONCLUSIONS: Advances in identifying the molecular basis of fragile X syndrome may help us understand the causes of neuropsychiatric disorders, and they will probably contribute to development of new and specific treatments.


Asunto(s)
Ataxia/genética , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/genética , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/farmacología , Síndrome del Cromosoma X Frágil/genética , Temblor/genética , Ataxia/diagnóstico , Trastorno Autístico , Síndrome del Cromosoma X Frágil/diagnóstico , Humanos , Discapacidad Intelectual , Mutación/genética , ARN Mensajero , Temblor/diagnóstico
4.
Biomed Res Int ; 2016: 4521767, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27294119

RESUMEN

Introduction. Manikin-based studies for evaluation of ventilation performance show high heterogeneity in the analysis and experimental methods used as we pointed out in previous studies. In this work, we aim to evaluate these potential limitations and propose a new analysis methodology to reliably assess ventilation performance. Methods. One hundred forty healthcare providers were selected to ventilate a manikin with two adult self-inflating bags in random order. Ventilation parameters were analysed using different published analysis methods compared to ours. Results. Using different methods impacts the evaluation of ventilation efficiency which ranges from 0% to 45.71%. Our new method proved relevant and showed that all professionals tend to cause hyperventilation and revealed a significant relationship between professional category, grip strength of the hand keeping the mask, and ventilation performance (p = 0.0049 and p = 0.0297, resp.). Conclusion. Using adequate analysis methods is crucial to avoid many biases. Extrapolations to humans still have to be taken with caution as many factors impact the evaluation of ventilation performance. Healthcare professionals tend to cause hyperventilation with current devices. We believe this problem could be prevented by implementing monitoring tools in order to give direct feedback to healthcare professionals regarding ventilation efficiency and ventilatory parameter values.


Asunto(s)
Maniquíes , Respiración Artificial/instrumentación , Adulto , Algoritmos , Femenino , Fuerza de la Mano , Humanos , Hiperventilación/etiología , Hiperventilación/prevención & control , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico , Respiración Artificial/efectos adversos , Respiración Artificial/métodos
6.
J Eur Acad Dermatol Venereol ; 28(12): 1816-20, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24206262

RESUMEN

BACKGROUND: Tumour necrosis factor alpha (TNF-α) inhibitors are associated with an increased risk of infections and with a still debatable risk of skin cancer. Furthermore, cutaneous human papillomavirus (HPV) infection may be involved in skin cancer. OBJECTIVES: Our primary objective was to assess the HPV DNA prevalence in psoriasis patients treated with TNF inhibitors and the secondary objective was to assess the same parameter before and during treatment. METHODS: Plucked eyebrow hairs were collected from 151 consecutive patients with moderate to severe chronic plaque psoriasis, including 48 patients treated with anti-TNF-α agents, 21 patients treated with methotrexate (MTX) and 82 patients with no previous systemic treatment. Among them, 38 patients were subsequently treated with either MTX or anti-TNF-α agents. HPV genotyping was performed using the HPV type-specific E7 PCR bead-based multiplex allowing the detection of 27 genus-α types, 25 genus-ß types, 16 genus-γ types and one single genus-µ type. Follow-up provided a total of 972.7 person-months of overall exposure for patients treated with TNF inhibitors and 326.9 person-months for patients treated with MTX. RESULTS: Our data confirm the high prevalence of ß-HPV infection in healthy skin of psoriasis patients (68.9%), with no significant difference between untreated patients (64.6%), patients treated with MTX (76.2%) and patients treated with anti-TNF-α agents (72.9%). The mean number of different HPV types and the distribution of HPV types were similar in different groups of patients. Moreover, in prospectively treated patients, we did not observe any change in the HPV DNA prevalence in the distribution of HPV types and the number of HPV types after a mean duration of treatment of 332 ± 39.8 days. CONCLUSION: Despite the small number of patients in our cohort, our results are quite encouraging in view of the increased use of anti-TNF-α agents in different auto inflammatory immune diseases.


Asunto(s)
ADN Viral/análisis , Cejas , Cabello/química , Papillomaviridae/genética , Psoriasis/tratamiento farmacológico , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Humanos , Psoriasis/fisiopatología
7.
Clin Genet ; 86(4): 378-82, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24028275

RESUMEN

Carriers of an FMR1 premutation allele (55-200 CGG repeats) often develop the neurodegenerative disorders, fragile X-associated tremor/ataxia syndrome (FXTAS). Neurological signs of FXTAS, parkinsonism and rapid onset of cognitive decline have not been reported in individuals with an unmethylated full mutation (FM). Here, we report a Chilean family affected with FXS, inherited from a parent carrier of an FMR1 unmethylated full mosaic allele, who presented with a fast progressing FXTAS. This case suggests that the definition of FXTAS may need to be broadened to not only include those with a premutation but also those with an expanded allele in FM range with a lack of methylation leading to elevated FMR1-mRNA expression levels and subsequent RNA toxicity.


Asunto(s)
Ataxia/genética , Metilación de ADN/genética , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/genética , Síndrome del Cromosoma X Frágil/genética , Temblor/genética , Anciano , Ataxia/complicaciones , Ataxia/patología , Chile , Síndrome del Cromosoma X Frágil/complicaciones , Síndrome del Cromosoma X Frágil/patología , Humanos , Masculino , Mosaicismo , Temblor/complicaciones , Temblor/patología
8.
Rev. chil. neuro-psiquiatr ; 46(4): 280-287, dic. 2008. tab
Artículo en Español | LILACS | ID: lil-547790

RESUMEN

Frontotemporal dementia is a neurodegenerative condition that presents with a number of distinct behavioral phenotypes. One of them is semantic dementia (SD), where exists a profound impairment for semantic knowledge related to atrophy of temporal poles. Pathologically, in most cases positive intraneuronal ubiquitin and tau negative inclusions are observed. SD is characterized by fluent, effortless, grammatical speech which lacks informational content, with limited and repetitive content, as well as semantic paraphasias. Also, patients may present with associative visual agnosia, surface dyslexia or dysgraphia, behavioral alterations. Both episodic and autobiographical memory are close to normality. Two female patients with fluent progressive aphasia are reported; they failed in a simple test of semantic association (to point to one of four objects with lesser relation to others). Autobiographical memory was fair. SD can be wrongly diagnosed as left-sided variant of Alzheimer's disease; absence of episodic amnesia and parietal defects may be useful for clinical diagnosis.


La demencia semántica es una variante de las atrofias lobares frontotemporales que se caracteriza por la degradación del conocimiento semántico, de los conceptos. En ella existe una atrofia predominante de los polos temporales, a veces asimétrica; la patología generalmente muestra neuronas con inclusiones ubiquitina (+) y tau (-). Se expresa como una afasia progresiva fluente, sin disartria ni agramatismo, con anomia y parafasias verbales o semánticas, poco informativa. Pueden existir agnosia visual asociativa y alteraciones conductuales; a veces existen alexia y/o agrafía de superficie. Hay respeto relativo de la memoria episódica y autobiográfica. Se presentan dos mujeres con afasia progresiva fluente, alteraciones conductuales y falla en una tarea semántica (4º excluido). A pesar de estos defectos la memoria autobiográfica y el desempeño en sus actividades cotidianas estaban dentro de lo normal. Se concluye que estos cuadros deben diferenciarse de los casos de enfermedad de Alzheimer de predominio izquierdo; el respeto de la memoria episódica y la falta de compromiso parietal descartarían clínicamente esta última patología.


Asunto(s)
Humanos , Femenino , Persona de Mediana Edad , Demencia/diagnóstico , Demencia/fisiopatología , Semántica , Conducta Verbal , Afasia , Lóbulo Frontal/fisiopatología
9.
Mol Plant Microbe Interact ; 21(2): 232-43, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18184067

RESUMEN

Sulfated laminarin (PS3) has been shown previously to be an elicitor of plant defense reactions in tobacco and Arabidopsis and to induce protection against tobacco mosaic virus. Here, we have demonstrated the efficiency of PS3 in protecting a susceptible grapevine cultivar (Vitis vinifera cv. Marselan) against downy mildew (Plasmopara viticola) under glasshouse conditions. This induced resistance was associated with potentiated H2O2 production at the infection sites, upregulation of defense-related genes, callose and phenol depositions, and hypersensitive response-like cell death. Interestingly, similar responses were observed following P. viticola inoculation in a tolerant grapevine hybrid cultivar (Solaris). A pharmacological approach led us to conclude that both callose synthesis and jasmonic acid pathway contribute to PS3-induced resistance.


Asunto(s)
Glucanos/farmacología , Inmunidad Innata/efectos de los fármacos , Inmunidad Innata/inmunología , Oomicetos/fisiología , Enfermedades de las Plantas/inmunología , Vitis/inmunología , Vitis/microbiología , Muerte Celular/efectos de los fármacos , Ciclopentanos/farmacología , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Genes de Plantas , Peróxido de Hidrógeno/metabolismo , Oomicetos/citología , Oomicetos/crecimiento & desarrollo , Oomicetos/ultraestructura , Oxilipinas/farmacología , Enfermedades de las Plantas/microbiología , Hojas de la Planta/citología , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/microbiología , Hojas de la Planta/ultraestructura , Estomas de Plantas/efectos de los fármacos , Estomas de Plantas/microbiología , Estomas de Plantas/ultraestructura , Esporas/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacos , Vitis/citología , Vitis/genética
10.
Rev. Hosp. Clin. Univ. Chile ; 19(3): 239-244, 2008. tab, ilus
Artículo en Español | LILACS | ID: lil-530342

RESUMEN

High grade gliomas are lethal cancers. Despite recent advances in surgery, radiotherapy and chemotherapy, the overall survival is 15 months for glioblastoma. They are among the most vascular of human tumors, making them especially attractive targets for angiogenesis inhibitors. Most clinical trials of these agents as monotherapy have failed to demonstrate survival benefit in unselected high grade glioma patient populations. Several mechanisms of treatment failure have been postulated. In response, there are new intervention strategies on course: the combination of target therapy with classic chemotherapy, multitargeted kinase inhibitors and combinations of single-targeted kinase inhibitors and the identification of correlative biomarkers. These advances provide real opportunities for the development of effective therapies for high grade gliomas.


Asunto(s)
Humanos , Masculino , Femenino , Glioma/clasificación , Glioma/terapia , Inhibidores de la Angiogénesis/administración & dosificación , Inhibidores de la Angiogénesis/uso terapéutico , Astrocitoma , Neoplasias Encefálicas
11.
Ultramicroscopy ; 100(3-4): 171-8, 2004 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15231307

RESUMEN

Despite cell wall reinforcement being a well-known defence mechanism of plants, it remains poorly characterized from a physical point of view. The objective of this work was to further describe this mechanism. Vitis vinifera cv Gamay cells were treated with UV-light (254 nm), a well-known elicitor of defence mechanisms in grapevines, and physical cell wall modifications were observed using the atomic force microscopy (AFM) under native conditions. The grapevine cell suspensions were continuously observed in their culture medium from 30 min to 24h after elicitation. In the beginning, cellulose fibrils covered by a matrix surrounded the control and treated cells. After 3 h, the elicited cells displayed sprouted expansions around the cell wall that correspond to pectin chains. These expansions were not observed on untreated grapevine cells. The AFM tip was used to determine the average surface elastic modulus of cell wall that account for cell wall mechanical properties. The elasticity is diminished in UV-treated cells. In a comparative study, grapevine cells showed the same decrease in cell wall elasticity when treated with a fungal biotic elicitor of defence response. These results demonstrate cell wall strengthening by UV stress.


Asunto(s)
Vitis/efectos de la radiación , Pared Celular/efectos de la radiación , Pared Celular/ultraestructura , Microscopía de Fuerza Atómica , Rayos Ultravioleta , Vitis/ultraestructura
12.
Trends Plant Sci ; 6(4): 177-83, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11286923

RESUMEN

Since its identification as an endothelium-derived relaxing factor in the 1980s, nitric oxide has become the source of intensive and exciting research in animals. Nitric oxide is now considered to be a widespread signaling molecule involved in the regulation of an impressive spectrum of mammalian cellular functions. Its diverse effects have been attributed to an ability to chemically react with dioxygen and its redox forms and with specific iron- and thiol-containing proteins. Moreover, the effects of nitric oxide are dependent on the dynamic regulation of its biosynthetic enzyme nitric oxide synthase. Recently, the role of nitric oxide in plants has received much attention. Plants not only respond to atmospheric nitric oxide, but also possess the capacity to produce nitric oxide enzymatically. Initial investigations into nitric oxide functions suggested that plants use nitric oxide as a signaling molecule via pathways remarkably similar to those found in mammals. These findings complement an emerging body of evidence indicating that many signal transduction pathways are shared between plants and animals.


Asunto(s)
Óxido Nítrico/fisiología , Plantas/metabolismo , Transducción de Señal , Aconitato Hidratasa/metabolismo , Adenosina Difosfato Ribosa/metabolismo , Animales , GMP Cíclico/metabolismo , Mamíferos , Óxido Nítrico/biosíntesis , Óxido Nítrico/química , Óxido Nítrico Sintasa/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Ácido Salicílico/metabolismo
13.
Plant Physiol ; 125(2): 564-72, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11161014

RESUMEN

The dynamics of microtubular cytoskeleton were studied in tobacco (Nicotiana tabacum cv Xanthi) cells in response to two different plant defense elicitors: cryptogein, a protein secreted by Phytophthora cryptogea and oligogalacturonides (OGs), derived from the plant cell wall. In tobacco plants cryptogein triggers a hypersensitive-like response and induces systemic resistance against a broad spectrum of pathogens, whereas OGs induce defense responses, but fail to trigger cell death. The comparison of the microtubule (MT) dynamics in response to cryptogein and OGs in tobacco cells indicates that MTs appear unaffected in OG-treated cells, whereas cryptogein treatment caused a rapid and severe disruption of microtubular network. When hyperstabilized by the MT depolymerization inhibitor, taxol, the MT network was still disrupted by cryptogein treatment. On the other hand, the MT-depolymerizing agent oryzalin and cryptogein had different and complementary effects. In addition to MT destabilization, cryptogein induced the death of tobacco cells, whereas OG-treated cells did not die. We demonstrated that MT destabilization and cell death induced by cryptogein depend on calcium influx and that MT destabilization occurs independently of active oxygen species production. The molecular basis of cryptogein-induced MT disruption and its potential significance with respect to cell death are discussed.


Asunto(s)
Proteínas Algáceas/farmacología , Citoesqueleto/ultraestructura , Microtúbulos/ultraestructura , Nicotiana/ultraestructura , Calcio/fisiología , Bloqueadores de los Canales de Calcio/farmacología , Células Cultivadas , Citoesqueleto/efectos de los fármacos , Ácido Egtácico/farmacología , Proteínas Fúngicas , Microtúbulos/efectos de los fármacos , Nicotiana/efectos de los fármacos , Nicotiana/fisiología
14.
Mol Plant Microbe Interact ; 13(8): 821-9, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10939253

RESUMEN

We previously reported that the signal transduction of cryptogein, an elicitor of defense reactions in Nicotiana tabacum cells, involves upstream protein phosphorylation. In the present study, induction of these early physiological events was further investigated with inhibitors of protein phosphatase (PP), okadaic acid, and calyculin A. Calyculin A mimicked the effects of cryptogein, inducing an influx of calcium, an extracellular alkalinization, and the production of active oxygen species (AOS), suggesting that during cryptogein signal transduction the balance between specific protein kinase (PK) and PP activities was modified. To identify the phosphorylated proteins that could be involved early in the elicitor signaling pathway, we analyzed by 2-D electrophoresis the in vivo phosphorylation status of proteins after cryptogein, staurosporine, and calyculin A treatments of tobacco cells (5 min). Of about 100 phospho-labeled polypeptides, 19 showed increased 32P incorporation after 5 min of cryptogein treatment. Phosphorylation of 12 of the 19 polypeptides depended upon calcium influx. Staurosporine inhibited the phosphorylations induced by cryptogein whereas calyculin A activated the phosphorylation of 18 of these polypeptides. This study highlighted the role of PKs and/or constitutive active PPs whose activation and inhibition, respectively, resulted in an increased phosphorylation of proteins that may be involved in cryptogein signal transduction. Identification of the phosphoproteins is in progress and will increase our knowledge of signal transduction pathways implicated in plant defense responses.


Asunto(s)
Proteínas Algáceas , Proteínas Fúngicas/metabolismo , Nicotiana/fisiología , Fosfoproteínas/fisiología , Plantas Tóxicas , Transducción de Señal/fisiología , Calcio/metabolismo , Inhibidores Enzimáticos/farmacología , Transporte Iónico , Fosfoproteínas Fosfatasas/antagonistas & inhibidores , Fosforilación , Inhibidores de Proteínas Quinasas
15.
J Biol Chem ; 274(49): 34699-705, 1999 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-10574936

RESUMEN

Cryptogein is a 98-amino acid proteinaceous elicitor of tobacco defense reactions. Specific binding of cryptogein to high affinity binding sites on tobacco plasma membranes has been previously reported (K(d) = 2 nM; number of binding sites: 220 fmol/mg of protein). In this study, biochemical characterization of cryptogein binding sites reveals that they correspond to a plasma membrane glycoprotein(s) with an N-linked carbohydrate moiety, which is involved in cryptogein binding. Radiation inactivation experiments performed on tobacco plasma membrane preparations indicated that cryptogein bound specifically to a plasma membrane component with an apparent functional molecular mass of 193 kDa. Moreover, using the homobifunctional cross-linking reagent disuccinimidyl suberate and tobacco plasma membranes incubated with (125)I-cryptogein, we identified, after SDS-polyacrylamide gel electrophoresis and autoradiography, two (125)I-cryptogein linked N-glycoproteins of about 162 and 50 kDa. Similar results were obtained using Arabidopsis thaliana and Acer pseudoplatanus plasma membrane preparations, whereas cryptogein did not induce any effects on the corresponding cell suspensions. These results suggest that either cryptogein binds to nonfunctional binding sites, homologues to those present in tobacco plasma membranes, or that a protein involved in signal transduction after cryptogein recognition is absent or inactive in both A. pseudoplatanus and A. thaliana.


Asunto(s)
Proteínas Algáceas , Arabidopsis/química , Proteínas Bacterianas , Sitios de Unión , Proteínas Fúngicas/química , Proteínas de la Membrana/química , Proteínas de Plantas/química , Arabidopsis/metabolismo , Toxinas Bacterianas/farmacología , Unión Competitiva , Membrana Celular/química , Membrana Celular/metabolismo , Reactivos de Enlaces Cruzados/metabolismo , Proteínas Fúngicas/aislamiento & purificación , Glicósido Hidrolasas/metabolismo , Cinética , Proteínas de la Membrana/metabolismo , Ácido Peryódico/metabolismo , Proteínas de Plantas/metabolismo , Plantas Tóxicas , Unión Proteica , Factores de Tiempo , Nicotiana/metabolismo
16.
Biochimie ; 81(6): 663-8, 1999 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10433120

RESUMEN

Cryptogein, a 98 amino acid protein secreted by the fungus Phytophthora cryptogea, induces a hypersensitive response and systemic acquired resistance in tobacco plants (Nicotiana tabacum var Xanthi). The mode of action of cryptogein has been studied using tobacco cell suspensions. The recognition of this elicitor by a plasma membrane receptor leads to a cascade of events including protein phosphorylation, calcium influx, potassium and chloride effluxes, plasma membrane depolarization, activation of a NADPH oxidase responsible for active oxygen species (AOS) production and cytosol acidification, activation of the pentose phosphate pathway, and activation of two mitogen-activated protein kinase (MAPK) homologues. The organization of the cryptogein responses reveals that the earliest steps of the signal transduction pathway involve plasma membrane activities. Their activation generates a complex network of second messengers which triggers the specific physiological responses. This study may contribute to our understanding of plant signaling processes because elicitors and a variety of signals including hormones, Nod factors, light, gravity and stresses share some common transduction elements and pathways.


Asunto(s)
Proteínas Algáceas , Proteínas Fúngicas/metabolismo , Proteínas de la Membrana/metabolismo , Nicotiana/metabolismo , Proteínas de Plantas/metabolismo , Plantas Tóxicas , Transducción de Señal , Animales , Membrana Celular/metabolismo , Nicotiana/inmunología
17.
Plant Physiol ; 118(4): 1317-26, 1998 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9847105

RESUMEN

Elicitins are a family of small proteins secreted by Phytophthora species that have a high degree of homology and elicit defense reactions in tobacco (Nicotiana tabacum). They display acidic or basic characteristics, the acidic elicitins being less efficient in inducing plant necrosis. In this study we compared the binding properties of four elicitins (two basic and two acidic) and early-induced signal transduction events (Ca2+ influx, extracellular medium alkalinization, and active oxygen species production). The affinity for tobacco plasma membrane-binding sites and the number of binding sites were similar for all four elicitins. Furthermore, elicitins compete with one another for binding sites, suggesting that they interact with the same receptor. The four elicitins induced Ca2+ influx, extracellular medium alkalinization, and the production of active oxygen species in tobacco cell suspensions, but the intensity and kinetics of these effects were different from one elicitin to another. As a general observation the concentrations that induce similar levels of biological activities were lower for basic elicitins (with the exception of cinnamomin-induced Ca2+ uptake). The qualitative similarity of early events induced by elicitins indicates a common transduction scheme, whereas fine signal transduction tuning is different in each elicitin.

18.
Plant J ; 15(6): 773-81, 1998 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9807816

RESUMEN

Elicitors of plant defence reactions (such as cryptogein, an elicitin produced by Phytophthora cryptogea, or oligogalacturonides (OGs)), induced in tobacco cell suspensions (Nicotiana tabacum var Xanthi) a rapid and transient activation of two protein kinases (PKs) with apparent molecular masses of 50 and 46 kDa, respectively. These PKs activated and phosphorylated at tyrosine residues, phosphorylated myelin basic protein (MBP) at serine/threonine residues. Both are recognized by anti-MAPK antibodies. The two MBP kinases possessed the same kinetics of activation, and their activation depended, to the same extent, on different exogenously applied compounds (staurosporine, lanthanum, EGTA). We demonstrate here that the activation of the MBP kinases is calcium dependent and sensitive to staurosporine, a protein kinase inhibitor which annihilates all known responses of tobacco cells to cryptogein. The activation of MBP kinases appeared to be independent of the production of active oxygen species (AOS) and insensitive to calyculin A, a protein phosphatase type 1 and 2A inhibitor. The activation of MAPKs is discussed in relation to the early responses induced by cryptogein.


Asunto(s)
Proteínas Algáceas , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Nicotiana/química , Plantas Tóxicas , Calcio/metabolismo , Proteínas Quinasas Dependientes de Calcio-Calmodulina/química , Activación Enzimática , Inhibidores Enzimáticos/farmacología , Proteínas Fúngicas/farmacología , Glucógeno Sintasa Quinasa 3 , Fosforilación , Extractos Vegetales/farmacología , Especies Reactivas de Oxígeno/metabolismo , Estaurosporina/farmacología , Tirosina/metabolismo
19.
Plant Mol Biol ; 35(3): 261-9, 1997 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9349250

RESUMEN

We report the successful combination of mRNA differential-display reverse-transcription PCR (DDRT-PCR) and 5'-rapid amplification of cDNA ends (5'-RACE) in order to isolate full-length cDNAs corresponding to genes activated in tobacco cells treated with cryptogein within 60 min. Cloning and sequencing of two cDNAs, called 'tcI 7' and 'tcI 14' (for tobacco cryptogein-induced), allowed the identification of open reading frames. Deduced amino-acid sequences of 'tcI 7' and 'tcI 14' showed significant homologies with a beta-type proteasome subunit and a transformer-2-like serine/arginine-rich (SR) ribonucleoprotein, respectively. The accumulation of mRNAs corresponding to 'tcI 7' started 30 min after the addition of cryptogein to tobacco cell suspensions and continued up to 180 min, whereas the accumulation of 'tcI 14' corresponding mRNAs was transitory between 30 and 60 min. These results indicated a transcriptional activation of the corresponding genes early after elicitation of tobacco cells by cryptogein. The biological significance of this activation remains to be elucidated.


Asunto(s)
Proteínas Algáceas , Cisteína Endopeptidasas/genética , ADN Complementario/aislamiento & purificación , Proteínas de Drosophila , Proteínas Fúngicas/farmacología , Genes de Plantas , Complejos Multienzimáticos/genética , Proteínas Nucleares/genética , Fosfoproteínas/genética , Ribonucleoproteínas/genética , Secuencia de Aminoácidos , Animales , Arginina , Secuencia de Bases , Clonación Molecular , ADN Complementario/química , Drosophila , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Genes de Plantas/efectos de los fármacos , Datos de Secuencia Molecular , Proteínas Nucleares/química , Fosfoproteínas/química , Proteínas de Plantas/química , Proteínas de Plantas/genética , Plantas Tóxicas , Complejo de la Endopetidasa Proteasomal , Proteínas de Unión al ARN , Ribonucleoproteínas/química , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido Nucleico , Serina , Factores de Empalme Serina-Arginina , Nicotiana
20.
Plant Cell ; 9(11): 2077-2091, 1997 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-12237354

RESUMEN

Application of the elicitor cryptogein to tobacco (cv Xanthi) is known to evoke external medium alkalinization, active oxygen species production, and phytoalexin synthesis. These are all dependent on an influx of calcium. We show here that cryptogein also induces calcium-dependent plasma membrane depolarization, chloride efflux, cytoplasm acidification, and NADPH oxidation without changes in NAD+ and ATP levels, indicating that the elicitor-activated redox system, responsible for active oxygen species production, uses NADPH in vivo. NADPH oxidation activates the functioning of the pentose phosphate pathway, leading to a decrease in glucose 6-phosphate and to the accumulation of glyceraldehyde 3-phosphate, 3- and 2-phosphoglyceric acid, and phosphoenolpyruvate. By inhibiting the pentose phosphate pathway, we demonstrate that the activation of the plasma membrane NADPH oxidase is responsible for active oxygen species production, external alkalinization, and acidification of the cytoplasm. A model is proposed for the organization of the cryptogein responses measured to date.

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