Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
1.
Mycopathologia ; 171(2): 139-49, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20582631

RESUMEN

Fusarium head blight (FHB) is an important disease throughout many of the world wheat-growing areas that have humid to semi-humid climate. The infection happens mainly during the anthesis of the wheat, when there have been favorable conditions of moisture and temperature. The direct relation of the infection to environmental factors makes possible the formulation of mathematical models that predict the disease. The causal agent of the FHB of the spike of wheat is attributed principally to Fusarium graminearum. High economic losses due yield decrease have been recorded in Argentina. In the present work, 67 isolates of Fusarium spp. were obtained from samples of wheat grains from Pampas region from 15 locations distributed in Buenos Aires, Entre Ríos, Santa Fe and Córboba provinces during 2006 and 2007 wheat-growing seasons. The identification of species from monosporic isolates was carried out by morphological characterization and use of species-specific PCR-based assays. Both identification criteria were necessary and complementary for the species determination, since in some cases the molecular identification was not specific. Scanty presence of F. graminearum was observed in 2006 wheat-growing season coinciding with the lack of favorable meteorological conditions for producing FHB infection events. High presence of F. graminearum isolates was observed in 2007 wheat-growing season, in accordance with moderate incidence of the disease according to spatial distribution of FHB incidence values. The aim of this report was to identify the causal agent of the FHB disease by different taxonomic criteria and to relate its occurrence with disease incidence values predicted by a weather-based model in Argentina.


Asunto(s)
Biodiversidad , Fusarium/clasificación , Fusarium/aislamiento & purificación , Enfermedades de las Plantas/microbiología , Triticum/microbiología , Argentina , Clima , ADN de Hongos/genética , Fusarium/citología , Fusarium/genética , Microscopía , Modelos Teóricos , Reacción en Cadena de la Polimerasa , Tiempo (Meteorología)
2.
Plant Pathol J ; 33(5): 441-449, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29018307

RESUMEN

Citrus canker is an important bacterial disease of citrus in several regions of the world. Strains of Xanthomonas citri type-A (Xc-A) group are the primary pathogen where citrus canker occurs. After Xc-A entered the Northeast of Argentina in 1974, the disease spread rapidly from 1977 to 1980 and then slowed down and remained moving at slow pace until 1990 when it became endemic. Citrus canker was detected in Northwest Argentina in 2002. This paper presents the main steps in the fight of the disease and the management strategies that have been used to control citrus canker at this time. We think the process might be usefull to other countries with the same situation. Results from more than 40 years of research in Northeast (NE) Argentina indicate that we are at the limit of favorable environment for the disease. The severity of citrus canker is greatly affected by the environment and El Niño Southern Oscillation (ENSO) phenomenon which causes cyclic fluctuations on the disease intensity in the NE region. Weather-based logistic regression models adjusted to quantify disease levels in field conditions showed that the environmental effect was strongly modulated by the distance from a windbreak. Production of healthy fruits in citrus canker endemic areas is possible knowing the dynamics of the disease. A voluntary Integrated Plan to Reduce the Risk of Canker has been in place since 1994 and it allows growers to export unsymptomatic, uninfested fresh fruit to countries which are free of the disease and require healthy, pathogen free fruits. The experience from Argentina can be replicated in other countries after appropriate trials.

3.
Arq Bras Cardiol ; 69(1): 51-3, 1997 Jul.
Artículo en Portugués | MEDLINE | ID: mdl-9532817

RESUMEN

We report the case of a 33-year-old woman in the 28th week of pregnancy and with signs of fetal death, admitted to hospital in an emergency due to pulmonary edema secondary to severe mitral valve stenosis. Intensive medical treatment was unsuccessful and the patient was submitted to an emergency percutaneous balloon mitral valvoplasty with prompt clinical improvement. Subsequent clinical deterioration secondary to fetal death was managed by cesarean section resulting in clinical establization. The patient was discharged 10 days after admission and at 11 months after the procedure she had mild symptoms without drug therapy and echocardiographic signs of mild residual mitral stenosis (mitral valve area: 2.0 cm2).


Asunto(s)
Cateterismo , Estenosis de la Válvula Mitral/terapia , Complicaciones Cardiovasculares del Embarazo/terapia , Edema Pulmonar/terapia , Enfermedad Aguda , Adulto , Urgencias Médicas , Femenino , Humanos , Embarazo
4.
Cell Mol Life Sci ; 62(24): 3092-9, 2005 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16314918

RESUMEN

The chaperone behaviour of bovine serum albumin was compared with that of alpha-crystallin. The chaperone activity was assessed by measuring: (i) the ability to antagonize protein aggregation induced by heat; (ii) the capability to protect the activity of thermally stressed enzymes and (iii) the effectiveness in assisting the functional recovery of chemically denatured sorbitol dehydrogenase. Despite the lack of structural analogies, both proteins show several functional similarities in preventing inactivation of thermally stressed enzymes and in reactivating chemically denatured sorbitol dehydrogenase. As with alpha-crystallin, the chaperone action of bovine serum albumin appears to be ATP independent. Bovine serum albumin appears significantly less effective than alpha-crystallin only in preventing thermally induced protein aggregation. A possible relationship between chaperone function and structural organization is proposed. Together, our results indicate that bovine serum albumin acts as a molecular chaperone and that, for its particular distribution, can be included in the extracellular chaperone family.


Asunto(s)
Chaperonas Moleculares/química , Albúmina Sérica Bovina/química , alfa-Cristalinas/química , Animales , Bovinos , Activación Enzimática , Estabilidad de Enzimas , Guanidina/farmacología , L-Iditol 2-Deshidrogenasa/química , Desnaturalización Proteica , Temperatura , Factores de Tiempo
5.
Cell Mol Life Sci ; 62(5): 599-605, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15747064

RESUMEN

alpha-Crystallin, the major component of the vertebrate lens, is known to interact with proteins undergoing denaturation and to protect them from aggregation phenomena. Bovine lens sorbitol dehydrogenase (SDH) was previously shown to be completely protected by alpha-crystallin from thermally induced aggregation and inactivation. Here we report that alpha-crystallin, in the presence of the SDH pyridine cofactor NAD(H), can exert a remarkable chaperone action by favoring the recovery of the enzyme activity from chemically denaturated SDH up to 77%. Indeed, even in the absence of the cofactor, alpha-crystallin present at a ratio with SDH of 20:1 (w:w) allows a recovery of 35% of the enzyme activity. The effect of ATP in enhancing alpha-crystallin-promoted SDH renaturation appears to be both nonspecific and to not involve hydrolysis phenomena, thus confirming that the chaperone action of alpha-crystallin is not dependent on ATP as energy donor.


Asunto(s)
L-Iditol 2-Deshidrogenasa/química , NAD/química , alfa-Cristalinas/metabolismo , Adenosina Trifosfato/química , Adenosina Trifosfato/fisiología , Animales , Bovinos , Activación Enzimática/fisiología , Guanidina/farmacología , L-Iditol 2-Deshidrogenasa/efectos de los fármacos , L-Iditol 2-Deshidrogenasa/metabolismo , NAD/fisiología , Desnaturalización Proteica , Pliegue de Proteína , alfa-Cristalinas/química
6.
J Biol Chem ; 275(42): 32559-65, 2000 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-10930418

RESUMEN

Sorbitol dehydrogenase (l-iditol:NAD(+) 2-oxidoreductase, E.C. 1.1.1. 14) (SDH) was significantly protected from thermally induced inactivation and aggregation by bovine lens alpha-crystallin. An alpha-crystallin/SDH ratio as low as 1:2 in weight was sufficient to preserve the transparency of the enzyme solution kept for at least 2 h at 55 degrees C. Moreover, an alpha-crystallin/SDH ratio of 5:1 (w/w) was sufficient to preserve the enzyme activity fully at 55 degrees C for at least 40 min. The protection by alpha-crystallin of SDH activity was essentially unaffected by high ionic strength (i.e. 0.5 m NaCl). On the other hand, the transparency of the protein solution was lost at a high salt concentration because of the precipitation of the alpha-crystallin/SDH adduct. Magnesium and calcium ions present at millimolar concentrations antagonized the protective action exerted by alpha-crystallin against the thermally induced inactivation and aggregation of SDH. The lack of protection of alpha-crystallin against the inactivation of SDH induced at 55 degrees C by thiol blocking agents or EDTA together with the additive effect of NADH in stabilizing the enzyme in the presence of alpha-crystallin suggest that functional groups involved in catalysis are freely accessible in SDH while interacting with alpha-crystallin. Two different adducts between alpha-crystallin and SDH were isolated by gel filtration chromatography. One adduct was characterized by a high M(r) of approximately 800,000 and carried exclusively inactive SDH. A second adduct, carrying active SDH, had a size consistent with an interaction of the enzyme with monomers or low M(r) aggregates of alpha-crystallin. Even though it had a reduced efficiency with respect to alpha-crystallin, bovine serum albumin was shown to mimic the chaperone-like activity of alpha-crystallin in protecting SDH from thermal denaturation. These findings suggest that the multimeric structural organization of alpha-crystallin may not be a necessary requirement for the stabilization of the enzyme activity.


Asunto(s)
Cristalinas/química , L-Iditol 2-Deshidrogenasa/química , Cristalino/enzimología , Animales , Cloruro de Calcio/farmacología , Bovinos , Cromatografía en Gel , Cristalinas/farmacología , Estabilidad de Enzimas , Calor , Cinética , L-Iditol 2-Deshidrogenasa/antagonistas & inhibidores , L-Iditol 2-Deshidrogenasa/metabolismo , Cloruro de Magnesio/farmacología , Soluciones , Termodinámica
7.
Arch Biochem Biophys ; 350(2): 245-8, 1998 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-9473298

RESUMEN

Bovine lens aldose reductase (ALR2), which catalyzes the NADPH-dependent reduction of 4-hydroxy-2-nonenal (HNE), is readily inactivated by its own substrate in a time- and concentration-dependent manner. Both DTT and NADP+ can prevent enzyme inactivation but neither extensive dialysis nor thiol-reducing treatment were able to restore enzyme activity once inactivation had occurred. Unlike the native enzyme, S-glutathionyl-modified ALR2 is unaffected by HNE, and can be easily reverted to the native form under thiol-reducing conditions. Evidence is presented of the involvement of Cys298 in the inactivation process. Zofenoprilat, an antioxidant thiol compound, mimics the effect of GSH. The possibility is raised that enzyme thiolation may function as a protection mechanism against the irreversible modification of ALR2.


Asunto(s)
Aldehído Reductasa/antagonistas & inhibidores , Aldehídos/farmacología , Animales , Antioxidantes/farmacología , Captopril/análogos & derivados , Captopril/farmacología , Bovinos , Cisteína/metabolismo , Ditiotreitol/farmacología , Disulfuro de Glutatión/farmacología , Cristalino/enzimología , NADP/farmacología
8.
Arq. bras. cardiol ; Arq. bras. cardiol;69(1): 51-3, jul. 1997. ilus
Artículo en Portugués | LILACS | ID: lil-214037

RESUMEN

Gestante com 33 anos na 28ª semana e sinais de óbito fetal foi admitida em caráter de urgência com quadro de edema pulmonar agudo secundário à estenose mitral grave. Com insucesso do tratamento medicamentoso intensivo, a paciente foi submetida à valvoplastia mitralpercutânea de emergência com melhora imediata. O agravamento subseqüente do quadro, atribuído ao óbito fetal, foi tratado através parto cesário com melhora clínica considerável. A paciente teve alta hospitalar no10§ dia, e 11 meses após o procedimento, encontraÄse em classe funcional I, sem uso de medicaçäo e com sinais ecocardiográficos de estenose mitral leve (área valvar: 2,0cm "ao quadrado".


Asunto(s)
Humanos , Femenino , Adulto , Embarazo , Cateterismo , Complicaciones Cardiovasculares del Embarazo/terapia , Urgencias Médicas , Estenosis de la Válvula Mitral/terapia
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA