RESUMEN
BACKGROUND: Pure tubular breast carcinoma is a rare and well-differentiated tumor with high survival and low local recurrence rate. Our study aims to determine the clinical, radiological, appropriate management, and prognosis of this carcinoma. MATERIALS AND METHODS: A review of Salah Azaiez institute registry from 2004 to 2019 was performed including seven cases of PTC of the breast. RESULTS: Clinical-pathologic features and outcomes were analyzed. The median follow-up was 3 years. In our study, we found that the cohort presented more frequently with pT1 disease and pN0 disease. Conservative surgery was more frequently indicated (five cases). All patients had hormone-receptor positivity and Human Epidermal growth factor Receptor 2 (HER2) negativity. The majority of tumors had a molecular profile luminal A and a low-grade SBR. In one case we found axillary lymph node metastasis. Adjuvant radiotherapy was indicated in all cases of breast conservation and in only one case of radical surgery. One patient received chemotherapy. The mean follow-up was 4 years. We did not find any local or distant recurrence in our study. CONCLUSION: PTC showed an excellent prognosis with a low SBR grade, a molecular profile luminal A, and a low incidence of recurrence.
Asunto(s)
Adenocarcinoma , Neoplasias de la Mama , Humanos , Femenino , Mama/patología , Pronóstico , Adenocarcinoma/patología , Metástasis Linfática , Neoplasias de la Mama/terapia , Recurrencia Local de Neoplasia , Estudios RetrospectivosRESUMEN
BACKGROUND: Primary breast lymphoma (PBL) is a very rare form of non-Hodgkin's lymphoma (NHL), defined as a malignant primary lymphoma occurring in the breast in the absence of previously detected lymphoma localizations. Our study aims to retrospectively evaluate the epidemiological, clinical, and imaging findings and therapeutic features of breast lymphomas in patients with primary lymphoma of the breast. MATERIALS AND METHODS: This is a retrospective study including 13 patients with primary non-Hodgkin's lymphoma of the breast treated at the Salah Azaiez Institute of Oncology from 2000 to 2019. This sample includes 1 case of follicular lymphoma, 2 cases of large T-cell lymphoma, and 10 cases of large B-cell lymphoma. RESULTS: Patients included in the study were aged between 17 and 89 years (average age of 52.6 years). All patients were referred because of a lump in the breast, and only one patient consulted with inflammatory signs in the breast. The average clinical size of the tumor was 7.2 cm, with a maximum of 15 cm. Mammography showed an oval mass with circumscribed margins in the majority of cases. Ultrasound showed in most cases a hypoechoic irregular mass or multilobulated mass with irregular margins and hypervascular on color Doppler. Magnetic resonance imaging (MRI) was performed on only three patients and showed a spiculated lesion with polycyclic limits. Eight patients underwent surgery. In our study breast lymphomas involved 10 cases of large B-cell lymphoma, one case of follicular lymphoma, and two cases of large T-cell lymphoma. In this series, 11 patients had localized stages (I + II) at diagnosis, and 2 patients had disseminated stages (stage III) of primary breast lymphoma. Seven patients underwent chemotherapy treatment alone, and five had chemotherapy with radiotherapy. The median follow-up of our patients was 53 months, ranging from 1 to 177 months. Overall survival was 71% at 3 years and 51% at 5 years. CONCLUSION: Primary breast lymphoma is an uncommon type of breast malignancy. The optimal treatment modality is still in question because of the rarity of this disease. However, the use of combination therapy produces the most favorable results. Surgery is not yet recommended.
Asunto(s)
Linfoma Folicular , Linfoma de Células B Grandes Difuso , Linfoma no Hodgkin , Linfoma de Células T , Humanos , Persona de Mediana Edad , Adolescente , Adulto Joven , Adulto , Anciano , Anciano de 80 o más Años , Estudios Retrospectivos , Linfoma no Hodgkin/tratamiento farmacológico , Linfoma de Células B Grandes Difuso/diagnóstico por imagen , Linfoma de Células B Grandes Difuso/terapia , Linfoma de Células B Grandes Difuso/patologíaRESUMEN
Chemical corneal burns are a common pathology. Those with strong bases penetrate deeply into the anterior segment and are particularly severe. We report the case of a patient suffering from corneal perforation secondary to an accidental projection of soda, and we propose to discuss the clinical and therapeutic particularities.
RESUMEN
Human hydatidosis occurs mainly as a result of infection with the larvae of Echinococcus granulosus. Cardiac echinococcosis is an uncommon disease and the interventricular septum is rarely involved. This article is a review of all of the literature related to hydatid cyst in the interventricular septum included in the PubMed database. Forty-five cases reported between 1964 and 2019 were identified.
Asunto(s)
Equinococosis/parasitología , Echinococcus granulosus/aislamiento & purificación , Cardiopatías/parasitología , Tabique Interventricular/parasitología , Animales , Echinococcus granulosus/genética , Echinococcus granulosus/fisiología , HumanosRESUMEN
BACKGROUND: Systemic sclerosis is a multisystem disorder characterized by tissue fibrosis and organ damage. Heart involvement is one of the main factors shortening survival, which may be underestimated by conventional echocardiography measurements. Two-dimensional speckle-tracking echocardiography is a powerful novel modality to assess subclinical myocardial dysfunction. AIM: The aim of this study is to investigate heart involvement in systemic sclerosis patients, and to determine the usefulness of ventricular longitudinal deformation using the Two-dimensional speckle tracking technology for an early detection of ventricular dysfunction. PATIENTS AND METHODS: Between May 2016 and September 2016, 25 patients with systemic sclerosis and 25 healthy subjects underwent echocardiography to assess heart abnormalities and the strain of the two ventricles using two dimensions' speckle tracking echography. RESULTS: The two groups were comparable in age and gender. Despite comparable left ventricle systolic function (left ventricular ejection fraction patients 64.58±8.87 vs. in healthy 68.2±7.41, P=0.19), patients presented altered longitudinal peak systolic strain values (global longitudinal strain: patients -17.42±1.62 vs. healthy -19.24±8.85, P<0.0001). Despite comparable pulmonary artery systolic pressure, there was a significant alteration in right ventricular systolic and diastolic function assessed by standard measurement. Longitudinal peak systolic strain of the right ventricle was significantly lower in patients compared with controls (P<0.01). CONCLUSION: Ventricular deformation analysis by two dimensions' speckle tracking echocardiography appears to be a sensitive method to detect early ventricular impairment in patients with systemic sclerosis.
Asunto(s)
Cardiomiopatías/diagnóstico por imagen , Cardiomiopatías/etiología , Ecocardiografía/métodos , Esclerodermia Sistémica/complicaciones , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
INTRODUCTION: The benefits of long-term non-invasive ventilation (NIV) in the management of chronic obstructive pulmonary disease (COPD) patients remain controversial. AIM: To analyze the characteristics of COPD patients under home NIV and to evaluate its impact among this population. METHODS: We carried out a retrospective study between January 2002 and April 2016 of COPD patients under long-term NIV at "la Rabta" and the Military Hospital. RESULTS: There were 27 patients with an average age of 64 and a sex ratio (M/F) of 0.92. Active smoking was reported in 96.3%. A persistent hypercapnia following an acute exacerbation of COPD with failure to wean the NIV was the main indication of long-term NIV. We noted a reduction in hospital admissions in the first year of 60% and in intensive care of 83.3% (P<10-3). There was no non-significant decrease of PaCO2 (4.5mmHg). There was no modification in FEV 1 and in FVC (P>0.05). The survival rate was 96.3% at 1 year, 83.3% at 2 years and a median survival of 24 months. CONCLUSIONS: Our study suggests that home NIV contributes to the stabilization of some COPD patients by reducing the hospitalizations rates for exacerbation. More prospective studies are needed to better assess the impact of NIV on survival and quality of life and to better define the COPD patients who require NIV.
Asunto(s)
Servicios de Atención de Salud a Domicilio , Ventilación no Invasiva , Enfermedad Pulmonar Obstructiva Crónica/terapia , Anciano , Anciano de 80 o más Años , Femenino , Hospitales Militares , Humanos , Masculino , Persona de Mediana Edad , Personal Militar/estadística & datos numéricos , Ventilación no Invasiva/instrumentación , Ventilación no Invasiva/métodos , Enfermedad Pulmonar Obstructiva Crónica/epidemiología , Insuficiencia Respiratoria/epidemiología , Insuficiencia Respiratoria/terapia , Estudios RetrospectivosRESUMEN
UNLABELLED: FAST-MI Tunisian registry was initiated by the Tunisian Society of Cardiology and Cardio-vascular Surgery to assess characteristics, management, and hospital outcomes in patients with ST-elevation myocardial infarction (STEMI). METHODS: We prospectively collected data from 203 consecutive patients (mean age 60.3 years, 79.8 % male) with STEMI who were treated in 15 public hospitals (representing 68.2 % of Tunisian public centres treating STEMI patients) during a 3-month period at the end of 2014. The most common risk factor was tobacco (64.9 %), hypertension (38.6 %), diabetes (36.9 %) and dyslipidemia (24.6 %). RESULTS: Among these patients, 66 % received reperfusion therapy, 35 % with primary percutaneous coronary interventions (PAMI), 31 % with thrombolysis (28.6 % of them by pre-hospital thrombolysis). The median time from symptom onset to thrombolysis was 185 and 358 min for PAMI, respectively. The in-hospital mortality was 7.0 %. Patients enrolled in interventional centers (n=156) were more likely to receive any reperfusion therapy (19.8 % vs 44.6 %; p<0.001) than at the regional system of care with less thrombolysis (26.9 % vs 44.6 %; p=0.008) and more PAMI (52.8 % vs 8.5 %; p<0.0001). Also the in-hospital mortality was lower (6.4 % vs 9.3 %) but not significant. CONCLUSIONS: Preliminary results from FAST-MI in Tunisia show that the pharmaco- invasive strategy should be promoted in non-interventional centers.
Asunto(s)
Angioplastia , Antiinflamatorios no Esteroideos/uso terapéutico , Anticoagulantes/uso terapéutico , Cardiología , Heparina/uso terapéutico , Infarto del Miocardio/terapia , Enfermedad Aguda , Adulto , Anciano , Anciano de 80 o más Años , Angioplastia/métodos , Angioplastia/estadística & datos numéricos , Quimioterapia Combinada , Femenino , Hospitales Públicos , Humanos , Masculino , Persona de Mediana Edad , Infarto del Miocardio/mortalidad , Estudios Prospectivos , Sistema de Registros , Factores de Riesgo , Sociedades Médicas , Resultado del Tratamiento , Túnez/epidemiologíaRESUMEN
Plants have evolved intracellular immune receptors to detect pathogen proteins known as effectors. How these immune receptors detect effectors remains poorly understood. Here we describe the structural basis for direct recognition of AVR-Pik, an effector from the rice blast pathogen, by the rice intracellular NLR immune receptor Pik. AVR-PikD binds a dimer of the Pikp-1 HMA integrated domain with nanomolar affinity. The crystal structure of the Pikp-HMA/AVR-PikD complex enabled design of mutations to alter protein interaction in yeast and in vitro, and perturb effector-mediated response both in a rice cultivar containing Pikp and upon expression of AVR-PikD and Pikp in the model plant Nicotiana benthamiana. These data reveal the molecular details of a recognition event, mediated by a novel integrated domain in an NLR, which initiates a plant immune response and resistance to rice blast disease. Such studies underpin novel opportunities for engineering disease resistance to plant pathogens in staple food crops.
Asunto(s)
Oryza/inmunología , Proteínas de Plantas/inmunología , Proteínas de Plantas/metabolismo , Receptores Inmunológicos/metabolismo , Cristalografía por Rayos X , Modelos Moleculares , Proteínas de Plantas/química , Proteínas de Plantas/genética , Conformación Proteica , Mapeo de Interacción de Proteínas , Receptores Inmunológicos/química , Receptores Inmunológicos/genética , Nicotiana/genética , Nicotiana/inmunologíaRESUMEN
Percutaneous mitral valvuloplasty (PMV) has emerged as the procedure of choice in treatment of mitral stenosis and has proved effectiveness in cases of mitral restenosis after surgical commissurotomy. However, this technique is costly, is not devoid of complication and success is not guaranteed. Indications of an attempted redo percutaneous mitral valvuloplasty (redo-PMV) are not well established. Hence the idea to study the immediate results of (re-PMV). PURPOSE OF WORK: The purpose of this study is to evaluate the immediate results of the re-PMV in patients with mitral restenosis and analyze the different clinical and laboratory findings to determine predictors of success of re-PMV to better selection of candidates for a new attempt PMV. METHODS: Retrospective study from a series of 40 procedures of re-PMV with the Inoue balloon succeeding a successful initial procedure, collected in the cardiology department of Habib Thameur hospital of Tunis between 1996 and 2011, in which we identified the data of clinical and paraclinical examinations. RESULTS: The mean age of patients was 43 ± 11 years [23; 63]. Of the population, 87.5% were female (five men and 35 women). The average time between the two procedures was 8 ± 4 years [1; 15]. The immediate procedural success defined by a mitral valve area greater or equal to 1.5 cm(2) and a grade less than or equal to 2 mitral regurgitation was obtained in 31 patients (77.5%). A severe mitral regurgitation (MR) was observed in three patients (7.5%). A cerebrovascular stroke occurred in one patient (2.5%). No death or cardiac tamponade were noted. Class III or IV of NYHA, a pre-procedural MR, pulmonary hypertension and an overall score of Padial greater than 10 were retained as predictors of failure. More the overall score of Wilkins is high (>8), more it is predictive of failure. The two components of the Wilkins score: valvular mobility and subvalvular apparatus (SVA) and the parameter of the redesign of the SVA score of Padial considered separately are also predictive of failure. Only a left atrial area less than or equal to 25 cm(2) was linked to high risk of severe MR. CONCLUSION: Redo percutaneous mitral valvuloplasty is a therapeutic alternative to surgery that is effective and promising interesting immediate results. Analysis of clinical and mainly echographic parameters is useful for predicting the success of the gesture, which will allow a better selection of candidates for re-PMV.
Asunto(s)
Valvuloplastia con Balón , Estenosis de la Válvula Mitral/terapia , Adulto , Valvuloplastia con Balón/efectos adversos , Valvuloplastia con Balón/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estenosis de la Válvula Mitral/diagnóstico , Selección de Paciente , Recurrencia , Reoperación , Estudios Retrospectivos , Accidente Cerebrovascular/etiología , Factores de Tiempo , Resultado del TratamientoRESUMEN
Every plant is closely associated with a variety of living organisms. Therefore, deciphering how plants interact with mutualistic and parasitic organisms is essential for a comprehensive understanding of the biology of plants. The field of plant-biotic interactions has recently coalesced around an integrated model. Major classes of molecular players both from plants and their associated organisms have been revealed. These include cell surface and intracellular immune receptors of plants as well as apoplastic and host-cell-translocated (cytoplasmic) effectors of the invading organism. This article focuses on effectors, molecules secreted by plant-associated organisms that alter plant processes. Effectors have emerged as a central class of molecules in our integrated view of plant-microbe interactions. Their study has significantly contributed to advancing our knowledge of plant hormones, plant development, plant receptors, and epigenetics. Many pathogen effectors are extraordinary examples of biological innovation; they include some of the most remarkable proteins known to function inside plant cells. Here, we review some of the key concepts that have emerged from the study of the effectors of plant-associated organisms. In particular, we focus on how effectors function in plant tissues and discuss future perspectives in the field of effector biology.
Asunto(s)
Proteínas Bacterianas/metabolismo , Proteínas Fúngicas/metabolismo , Interacciones Huésped-Patógeno , Plantas/metabolismo , Plantas/microbiología , Células Vegetales/metabolismo , Células Vegetales/microbiología , Transducción de SeñalRESUMEN
Congenital rubella syndrome resulting from maternal rubella infection can cause serious multisystemic malformations resulting in severe morbidity and mortality. After immunization, its incidence has been reduced in the developed world, though it remains a real problem in developing countries since it causes many handicaps. In Tunisia, despite including rubella immunization in the routine national program on immunization for girls once they reach the age of 12, the congenital rubella syndrome still exists. We describe the clinical pattern and the outcome of congenital rubella syndrome in 2 infants and emphasize the necessity of recommending universal screening and follow-up vaccination of susceptible females and including rubella immunization in the routine national immunization program, especially in developing countries.
Asunto(s)
Síndrome de Rubéola Congénita , Femenino , Humanos , Recién Nacido , Masculino , Síndrome de Rubéola Congénita/diagnóstico , Síndrome de Rubéola Congénita/prevención & control , Vacuna contra la Rubéola , TúnezRESUMEN
OBJECTIVE: The leaves extracts of Cestrum parqui were reported to have spermicidal activity. The current investigation identified the spermicidal component of the extracts and evaluated its spermicidal potential in vitro, particularly the effects on sperm motility and vitality. METHODS: Sperms were prepared by discontinuous buoyant density gradient centrifugation and incubated with varying concentrations of extract from C. parqui (40-250 µg/ml) at 37°C and 5% CO(2). The mode of spermicidal action was evaluated by sperm motility and vitality at different intervals ranging from 5 to 240 minutes. Morphological changes in human spermatozoa after exposure to the extract were evaluated under transmission electron microscope. RESULTS: A dose- and time-dependent effect of this extract on sperm motility and viability was observed. The mean effective concentration of extracts that induced irreversible immobilization was 250 µg/ml. Transmission electron microscope revealed a significant damage to sperm membrane in head and acrosomal membranes, notable swelling and disruption. CONCLUSION: Our study indicates that this natural extract has potential spermicidal effect in vitro. It can adequately replace nonoxynol-9 in vaginal contraceptives to make them more vaginally safe and ecofriendly.
Asunto(s)
Cestrum/química , Extractos Vegetales/farmacología , Hojas de la Planta/química , Motilidad Espermática/efectos de los fármacos , Espermicidas/farmacología , Espermatozoides/efectos de los fármacos , Acrosoma/efectos de los fármacos , Membrana Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Humanos , Masculino , Microscopía Electrónica de Transmisión , Espermatozoides/fisiología , Espermatozoides/ultraestructuraRESUMEN
BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a primary electrical myocardial disease characterized by exercise- and stress-related ventricular lachycardia manifested as syncope and sudden death usually in child and teenager and was rarely described in adults. The management includes betablockade, with the use of implantable cardioverter defibrillators if medical treatment is insufficient. AIM: Report a new case of CPVT. OBSERVATION: We report a case of a 43 years old patient in whom CPVT diagnosis was made during his exploration for palpitations occurring with the effort. Registration Holter ECG revealed several episodes of supraventricular tachycardia and episodes of nocturnal sino-atrial block. The patient had an ICD and betablockade treatment. CONCLUSION: The TVPC in adult can manifest with attenuated symptoms that can be summarized with palpitations with the exertion. The supraventricular arrhythmias and sinus dysfunction may be at the forefront of Electrocardiographic manifestations. The prognosis of this form seems better than the TVPC of the child. Treatment with betablockade appears to be effective but existing dysfunction sinus facilitates decision to implant the ICD.
Asunto(s)
Taquicardia Ventricular/diagnóstico , Adulto , Electrocardiografía Ambulatoria , Humanos , Masculino , Esfuerzo Físico , Taquicardia Ventricular/terapiaRESUMEN
Introduction: L'asthme aigu grave constitue une urgence medicale pouvant mettre en jeu le pronostic vital. L'objectif de ce travail est d'evaluer les aspects epidemiologiques; cliniques; paracliniques et therapeutiques de l'asthme aigu grave en reanimation .Patients et methode: Il s'agissait d'une etude retrospective ayant collige tous les patients de plus de 15 ans admis dans le service de reanimation de l'hopital Principal de Dakar entre octobre 2000 et octobre 2002 pour une crise d'asthme avec presence de criteres de gravite. Nous avions analyse les elements epidemiologiques; les aspects cliniques et paracliniques ainsi que les differentes modalites de prise en charge medicamenteuse et la ventilation artificielle.Resultats: Trente trois patients avaient ete inclus dans cette etude. L'age moyen etait de 44 ans avec un sex-ratio de 1;65. A l'admission 26des patients ventiles presentaient un silence auscultatoire; un etat de choc ou un coma avec score de Glasgow inferieur a 12. Au niveau de la gazometrie; on notait la presence d'une acidose de type respiratoire; metabolique ou mixte chez respectivement 48; 9et 12des patients. La ventilation assistee etait indiquee chez 45des patients. L'evolution etait le plus souvent favorable avec un taux de mortalite de 6.Conclusion: Le pronostic des patients admis dans un service de reanimation pour asthme aigu grave est favorable
Asunto(s)
Asma , Asma/diagnóstico , Asma/epidemiologíaRESUMEN
ABSTRACT A light sphagnum peat mix inoculated with Trichoderma hamatum 382 consistently provided a significant (P = 0.05) degree of protection against bacterial spot of tomato and its pathogen Xanthomonas euvesicatoria 110c compared with the control peat mix, even though this biocontrol agent did not colonize aboveground plant parts. To gain insight into the mechanism by which T. hamatum 382 induced resistance in tomato, high-density oligonucleotide microarrays were used to determine its effect on the expression pattern of 15,925 genes in leaves just before they were inoculated with the pathogen. T. hamatum 382 consistently modulated the expression of genes in tomato leaves. We identified 45 genes to be differentially expressed across the replicated treatments, and 41 of these genes could be assigned to at least one of seven functional categories. T. hamatum 382-induced genes have functions associated with biotic or abiotic stress, as well as RNA, DNA, and protein metabolism. Four extensin and extensin-like proteins were induced. However, besides pathogenesis-related protein 5, the main markers of systemic acquired resistance were not significantly induced. This work showed that T. hamatum 382 actively induces systemic changes in plant physiology and disease resistance through systemic modulation of the expression of stress and metabolism genes.
RESUMEN
We performed a study to analyze epidemiological characteristics and bacteriological profile of infectious endocarditis (I.E) in the area of Sfax (Tunisia). We analyzed, retrospectively, all cases of I.E, according to Duke Criteria, hospitalized in the CHU Hédi Chaker of Sfax between January 1997 and December 2000. Bacteriological investigation included blood culture, cardiac valve culture and serology. Seventy-two cases of I.E were diagnosed. The average of age was 32.3 years. 47.3% of the patients did not have cardiac disease, 25% had a valvular prosthesis, 20.8% a native valvulopathy and 6.9% a congenital cardiopathy. Antecedent of acute rheumatic fever was noted in 66% of I.E on native valvulopathy and in 55.5% of I.E on prosthesis. The mitral valve was involved in 39%, the aortic in 27.5% and the two in 26% of the cases. The origin of bacteremia was found or supposed in 55.5% of the cases and was commonly dental (33 % of EI). The bacteriological diagnosis was positive in 51 cases (70.8%). Staphylococci were isolated in 17 cases (23.6%), Streptococci in 17 cases (23.6%) and dominated by oral streptococci (12 cases). Chlamydial serology was positive in 8 cases (11.1%). Diagnosis of infectious endocarditis due to Chlamydia pneumoniae was confirmed in a case by genomic amplification (PCR) and in situ hybridization on the valve. Endocarditis in Tunisia remains frequent. It reaches with predilection the young person in particular with rheumatic heart diseases. The bacteriological profile remains dominated by Streptococci and the Staphylococci.
Asunto(s)
Endocarditis Bacteriana/microbiología , Adolescente , Adulto , Anciano , Niño , Femenino , Válvulas Cardíacas/microbiología , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Cardiopatía Reumática/epidemiología , Túnez/epidemiologíaRESUMEN
We report unusual magnetic resonance imaging (MRI) findings in a diabetic patient with neglected hypertension and hyperglycemia, presenting with seizures and coma. Outcome was fatal despite intensive care. The MRI findings included bilateral insular and temporo-occipital grey and white matter involvement, and numerous, scattered, lacunar-like lesions involving the peripheral and deep white matter, basal ganglia grey matter, and brainstem. Lesions had a low apparent diffusion coefficient, and some enhanced following contrast injection. Hypertensive encephalopathy with widespread and severe acute small-vessel disease was considered. Pathophysiology is discussed.
Asunto(s)
Complicaciones de la Diabetes/patología , Encefalopatía Hipertensiva/etiología , Encefalopatía Hipertensiva/fisiopatología , Enfermedad Aguda , Femenino , Humanos , Encefalopatía Hipertensiva/patología , Imagen por Resonancia Magnética , Microcirculación , Persona de Mediana EdadRESUMEN
Activation of two mitogen-activated protein kinases (MAPKs), wound-induced protein kinase (WIPK) and salicylic acid-induced protein kinase (SIPK), is one of the earliest responses that occur in tobacco plants that have been wounded, treated with pathogen-derived elicitors or challenged with avirulent pathogens. We isolated cDNAs for these MAPKs (NbWIPKand NbSIPK) from Nicotiana benthamiana. The function of NbWIPK and NbSIPK in mediating the hypersensitive response (HR) triggered by infiltration with INF1 protein (the major elicitin secreted by Phytophthora infestans), and the defense response to an incompatible bacterial pathogen (Pseudomonas cichorii), was investigated by employing virus-induced gene silencing (VIGS) to inhibit expression of the WIPK and SIPK genes in N. benthamiana. Silencing of WIPK or SIPK, or both genes simultaneously, resulted in reduced resistance to P. cichorii, but no change was observed in the timing or extent of HR development after treatment with INF1.
Asunto(s)
Proteínas Fúngicas/farmacología , Proteínas Quinasas Activadas por Mitógenos/genética , Nicotiana/genética , Enfermedades de las Plantas/genética , Proteínas de Plantas , Proteínas Algáceas , Secuencia de Aminoácidos , Regulación de la Expresión Génica de las Plantas , Silenciador del Gen , Inmunidad Innata/genética , Sistema de Señalización de MAP Quinasas , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Datos de Secuencia Molecular , Phytophthora , Hojas de la Planta , Plantas Modificadas Genéticamente , Proteínas , Alineación de Secuencia , Virus del Mosaico del Tabaco/patogenicidadRESUMEN
SUMMARY Mitogen-activated protein kinases (MAPKs) play pivotal roles in the signal transduction pathway of plant defence responses against pathogens. A search for MAPK-interacting proteins revealed an interaction between a Nicotiana benthamiana MAPK, SIPK (NbSIPK) and cytosolic Hsp90 (NbHsp90c-1) in yeast two-hybrid assay. To study the function of Hsp90 in disease resistance, we silenced NbHsp90c-1 in N. benthamiana by virus-induced gene silencing (VIGS) with Potato virus X (PVX). NbHsp90c-1 silenced plants exhibited: (1) a stunted phenotype, (2) no hypersensitive response (HR) development after infiltration with the Phytophthora infestans protein INF1 and a non-host pathogen Pseudomonas cichorii that normally triggers HR in N. benthamiana, (3) compromised non-host resistance to P. cichorii, and (4) consistently reduced transcription levels of PR (pathogenesis related) protein genes. Similar phenotypes were observed also for plants in which a cytosolic Hsp70 (NbHsp70c-1), a gene for another class of molecular chaperon, was silenced. Hsp90 was isolated as a MAPK-interacting protein in yeast two-hybrid assay, therefore we tested the effect of NbHsp90c-1 silencing as well as NbHsp70c-1 silencing on the HR development caused by infiltration of a hyperactive potato MAPKK (StMEK1(DD)). No difference in the timing or extent of HR was found among NbHsp90c-1 silenced, NbHsp70c-1 silenced and control plants. This result indicates that observed impairment of INF1- and P. cichorii-mediated HR development in NbHsp90c-1 silenced and NbHsp70c-1 silenced plants was not caused by the abrogation in MAPK function downstream of active MAPKK that leads to HR. These findings suggest essential roles of Hsp90 and Hsp70 in plant defence signal transduction pathway upstream or independent of the MAPK cascade.