Ana María González

Detección de metabolitos fúngicos con actividad tóxica mediante bioensayo sobre Artemia salina

Resumen El objetivo fue aplicar un ensayo de toxicidad sobre Artemia salina para la deteccion de metabolitos fungicos toxicos, obtenidos a partir de hongos contaminantes de hierbas medicinales y alimentos. Los extractos fungicos fueron clasificados, segun el porcentaje de mortalidad hallado, como: no toxico (NT), levemente toxico (LT), toxico (T) y muy toxico (MT). En los tipos T y MT se investigo la presencia de micotoxinas. Seis extractos resultaron de tipo T (8,5%). Penicillium brevicompactum Dierckx, aislado de un embutido, fue el unico MT, debido principalmente a la presencia de ocratoxina A y de otros dos metabolitos no identificados.

Structural and ultrastructural alterations in BALB/c mice: effects of Penicillium citrinum metabolites.

The aims of this work were to determine the effect of feeding BALB/c mice a diet containing culture materials of a citrinin producing strain of Penicillium citrinum(Thom). Changes in hematological parameters, serum chemistry and histological changes in liver, kidney and heart were determined. After 60 days, control treated (CT) mice appeared normal in all respects, whereas, the mice fed the feeds supplemented with Penicillium (CMT) showed decreased weight gain, lower hematocrits, increased serum alanine aminotransferase (ALT) and clear signs of renal and hepatotoxicity based on histological changes. Changes observed in the liver of CMT mice included portal and lobular infiltration of polymorphonuclear cells, with concomitant hepatocellular necrosis, hepatic steatosis, prominent Kupffers cells, hemosiderin granules in the cytoplasm of periportal hepatocytes and other lipid inclusions in the surrounding mitochondria were also observed. Our findings suggest that in vivo, P. citrinum Thom metabolites, which contain citrinin, could cause illnesses such as toxic hepatitis or intravascular hemolysis.

Genetic Diversity of Cercospora kikuchii Isolates From Soybean Cultured in Argentina as Revealed by Molecular Markers and Cercosporin Production

Leaf blight and purple seed, caused by the fungal pathogen Cercospora kikuchii (Matsumoto & Tomoyasu) M. W. Gardner are very important diseases of soybean (Glycine max L. Merr.) in Argentina. The aims of this work were: (a) to confirm and to assess the genetic variability among C. kikuchii isolates collected from different soybean growing areas in Santa Fe province using inter simple sequence repeats (ISSR) markers and sequence information from the internal transcribed spacer (ITS) region of rDNA and (b) to analyze the cercosporin production of the regional C. kikuchi isolates in order to assess whether there was any relationship between the molecular profiles and the toxin production. Isolates from different regions in Santa Fe province were studied. The sequence of the ITS regions showed high similarity (99–100%) to the GenBank sequences of C. kikuchii BRCK179 (accession number AY633838). The ISSR markers clustered all the isolates into many groups and cercosporin content was highly variable among isolates. No relationship was observed between ITS region, ISSR groups and origin or cercosporin content. The high degree of genetic variability and cercosporin production among isolates compared in this study characterizes a diverse population of C. kikuchii in the region.

(GTG)5 microsatellite regions in citrinin-producing Penicillium

Resumen Los principales criterios que se utilizan en la taxonomia fungica, asi como en la descripcion de las especies, son sus caracteres morfologicos y de cultivo y sus propiedades bioquimicas. Sin embargo, a veces, resulta muy dificil clasificarlos debido a su variabilidad fenotipica, lo que es particularmente cierto con el genero Penicillium. Los objetivos de este trabajo fueron determinar regiones microsatellites (GTG)5 en Penicillium potenciales productores de citrinina e investigar la utilidad de las mismas para caracterizarlos. Penicillium citrinum Thom y Penicillium chrysogenum Thom fueron aislados a partir de diferentes alimentos. La identificacion de las especies se llevo a cabo aplicando las claves taxonomicas clasicas y la produccion de citrinina se determino mediante cromatografia en capa delgada. Se demostro la existencia de los microsatelites, como secuencias cortas y reiteradas, en todas las especies estudiadas. Los patrones obtenidos en todas las cepas de P. citrinum fueron muy similares y permitieron agruparlas segun la cantidad de toxina producida. Los aislamientos de P. chrysogenum no pudieron ser agrupados de la misma manera.

Identification of a 2244 base pair interstitial deletion within the human ESR1 gene in the Spanish population

Background: The ESR1 AGATA haplotype is composed of five markers located within introns 5 and 6 of the human oestrogen receptor 1 (ESR1) gene. This haplotype has been studied in several male urogenital tract anomalies and male infertility. In one of these studies, a deviation from Hardy–Weinberg equilibrium (DHW) was found for the ESR1 AGATA marker rs3020375 in two groups of healthy controls. In the present study, we investigated whether the observed DHW is caused by structural variants present within the ESR1 gene. Participants: 229 family units achieving pregnancy through assisted reproductive technologies (n = 129) or by natural means (n = 100), 2465 general Spanish population controls and 162 men with idiopathic infertility. Main outcome measurements: Segregation analyses of genetic markers in family units and case–control genetic association studies. Results: We identified a new interstitial deletion of 2244 base pairs within intron 6 of the human ESR1 gene as the cause for the observed DHW. This new variant presents a 10% allelic frequency in the general Spanish population and it is associated with idiopathic male infertility (OR = 1.51; p = 0.03). The percentage of infertile couples in which both members carried the ESR1 deletion (10.08%) was also a higher than expected value of 6% (p = 0.03). Conclusions: We have characterised a novel structural variation in human ESR1 gene. The available data indicate a deleterious action of the ESR1 deletion in both male and couple fertility. The potential effects of this deletion on other oestrogen-related diseases need to be determined.

Cercospora kikuchii aislada en la provincia de Santa Fe (Argentina): variabilidad genética y producción de cercosporina in vitro

Resumen Los objetivos del trabajo fueron analizar la variabilidad genetica y la produccion de cercosporina in vitro de los aislamientos regionales de Cercospora kikuchii obtenidos a partir de soja cultivada en la region centro-norte de la provincia de Santa Fe (Argentina) y evaluar si existia relacion entre los perfiles de RAPD obtenidos y la produccion de la toxina. Se utilizo la cepa C. kikuchii NBRC 6711 y 13 aislamientos obtenidos de plantas de soja, con sintomas de tizon de la hoja. La produccion y cuantificacion de cercosporina se analizo previo cultivo en agar papa dextrosa. La toxina se extrajo en medio alcalino y su concentracion se determino por espectrofotometria. La poblacion de C. kikuchii estudiada resulto variable geneticamente, detectandose nueve grupos, y en su capacidad de producir cercosporina in vitro. No se encontro relacion entre la produccion de la toxina y los perfiles por RAPD.

Phenotypic and Genotypic Variability in Cercospora kikuchii Isolates from Santa Fe Province, Argentina

More than 100 fungal diseases affecting soybean (Glycine max (L.) Merr.) culture have been found worldwide, though only 35 of them are of great economic concern since they cause a 10 to 15% yield decrease (Ivancovich & Botta, 2003; Yeh & Sinclair, 1980). In Argentina, “Late-cycle diseases” (LCD) constitute a complex of infections affecting the culture of this leguminous, particularly in the reproductive stages. The first symptoms appear from the onset of carpel formation, thus producing premature plant maturation, a reduction in yield (5 to 8%) and seed quality loss. Due to the climate conditions of the region, leaf blight and purple seed stain, is one of the LCD prevailing in the central-northern region of Santa Fe Province (Formento, 2005; Ivancovich & Botta, 2003). The causal agent of the disease is the fungus Cercospora kikuchii (T. Matsumoto & Tomoyasu) M.W. Gardner, which produces irregular injuries on the leaves, forming reddish-purple necrotic areas, pale pink to dark purple stains on the seeds, together with cracks on the outer coat (Formento, 2005). C. kikuchii belongs to the Cercospora taxonomic complex, which is assumed to be host-specific (Crous & Braun, 2003), and therefore its species are normally identified from the phenotypic characteristics they show when grown on their natural substrate, being much more difficult to be characterized from artificial media (Almeida et al., 2005; Gams et al., 2007). One of the most important factors determining the pathogenicity of this fungus is the production of cercosporin, a red exotoxin (Kuyama & Tamura, 1957; Upchurch et al.,1991). Another aspect to consider is the genetic variability found in some fungi, which has determined the description of different races; that is why the use of some methodology to detect interand intraspecific variations between isolates is recommended (Kuyama & Tamura, 1957). In this sense, the Random Amplified Polymorphic DNA (RAPD) technique allows the differentiation between strains since amplification focuses only on the whole genome (Tigano et al., 2003; Williams et al., 1990). Although some Brazilian research groups have been studying aspects related with this phytopathogen (Almeida et al., 2003) only a few reports have been found in Argentina and, in particular in Santa Fe Province, about epidemiology and population structure of C. kikuchii.