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.

[Cercospora kikuchii isolated from Province of Santa Fe (Argentina): genetic variability and cercosporin production]. / Cercospora kikuchii aislada en la provincia de Santa Fe (Argentina): variabilidad genética y producción de cercosporina in vitro.

The aims of the present study were to analyze the genetic variability of Cercospora kikuchii isolates and the in vitro cercosporin production, of these isolates obtained from soybean at the central-northern region of Santa Fe province (Argentina). Also the relationship between RAPD profiles and toxin production was also assessed. The strain C. kikuchii NBRC 6711 and 13 soybean isolates with symptoms of leaf blight were tested. Cercosporin production was analyzed by growing the fungus on Potato Dextrose Agar, extracting the toxin in alkaline medium and determining its concentration by spectrophotometry. The population of C. kikuchii studied showed variability, both genotypically, nine different groups were encountered, and have the ability to produce cercosporin. No relationship was found between toxin production and the RAPD profiles.

[Detection of fungal metabolites showing toxic activity through Artemia salina bioassay]. / Detección de metabolitos fúngicos con actividad tóxica mediante bioensayo sobre Artemia salina.

The aim of this study was to detect toxic metabolites from fungi contaminating food and medicinal herbs by applying the toxicity assay to Artemia salina. According to toxicity percentages, the extracts were classified as nontoxic (NT), slightly toxic (ST), toxic (T) and highly toxic (HT). Those classified as T and HT were assayed for mycotoxins. Only 6 out of 71 strains were found to be T (8.5%) for A. salina. Penicillium brevicompactum Dierckx, isolated from sausages, was found to be HT, mainly due to the presence of ochratoxin A and two other unidentified metabolites.

(GTG)5 microsatellite regions in citrinin-producing Penicillium.

Morphological and cultural characteristics, as well as biochemical properties, are the main criteria used in fungal taxonomy and in the standard description of fungi species. Sometimes, however, this criterion is difficult to apply due to fungal phenotypic variations. This is particularly true in the genus Penicillium. The aims of this work were to determine (GTG)5 microsatellite sequence in potentially citrinin-producing Penicillium strains and to investigate if this sequence could be useful to characterize such fungi. Penicillium citrinum Thom and Penicillium chrysogenum Thom were isolated from different foods. The identification of the isolates at species level was carried out according to classical taxonomy. The production of citrinin was determined by thin layer chromatography. This study proved that microsatellite regions exist as short repeated sequences in all tested strains. The patterns were very similar for all P. citrinum isolates and it was possible to group them in function of the quantity of citrinin produced. Yet, not similar clusters were obtained when P. chrysogenum isolates were analyzed.

[Prevalence of intestinal helminthiasis in primary school children in Santa Fé city]. / Prevalencia de helmintiosis intestinales en escolares de la ciudad de Santa Fe.

The aims of this work were: 1.--to determine the intestinal helminth prevalence in children who live and attend primary schools in Santa Fe city. 2.--to characterize the socio-cultural and sanitary aspects of the children studied and consequently to group them in three supposed strata (hypo, meso and hyperendemic). The study was carried out during 1998. Considering the following variables: kind of streets, sewers and water supplies, parents' educational levels, satisfied or unsatisfied basic needs, the city was divided in three strata, according to the intestinal helminthic prevalence expected: 1--hypoendemic (< 25%), 2--mesoendemic (25-75%) and 3--hyperendemic (> 75%). Schools with children of both sexes, and ages between 5 and 13 who belonged to each one of the supposed strata, were identified. A direct parasitic examination and a Kato Katz technique were performed on a stool specimen of each selected child. An epidemiological survey was answered by the children's parents. The prevalence of helminths and geohelminths, with 95% confidence intervals, were respectively: total sample (n = 163). 36.2% and 34.4%; stratum 1 (n1 = 60) 0% and 0%; stratum 2 (n2 = 70) 41% (29.9-52.9) y 38.6% (27.2-50.0) and stratum 3 (n3 = 33) 91% (81.1-100) and 87.9% (76.6-99.2). The above-mentioned variables, related to the socio-cultural and sanitary aspects, allowed to identify three well defined strata: hypoendemic, mesoendemic and hyperendemic, according to the different helminth prevalence detected among pupils who attend primary level school in Santa Fe city.

[Selective vs. mass treatment with antihelminthic drugs: experience in two hyperendemic communities]. / El tratamiento antihelmíntico selectivo frente al tratamiento masivo. Experiencia en dos comunidades hiperendémicas.

OBJECTIVE: To compare the prevalence and intensity of soil-transmitted nematode infection among children from two hyperendemic communities who were treated with antihelminthic drugs under two different regimens: selective or individual treatment was administered to members of one of the communities, and repeated mass treatment was given to the control community. METHODS: The study population was comprised of 909 children of both sexes between the ages of 2 and 13 from two peri-urban communities: Las Lomas and El Abastos, both in Santa Fe, Argentina. A prospective, longitudinal, quasi-experimental study was carried out in these communities. During the 22-month study period, 5 parasitologic controls were performed and results were qualitatively and quantitatively examined. Treatment with antihelminthic drugs was given at controls 0, 2, 3, and 4. At Las Lomas, selective treatment was administered to those in sample A (n = 55) who were positive for parasites; in El Abasto, mass treatment was given to all children, including those in sample B (n = 50). Both samples received follow-up. RESULTS: The prevalence and intensity of A. lumbricoides infections were found to be significant in El Abasto. No differences were detected in the case of T. trichiura. When prevalence and parasitic burden of A. lumbricoides were compared among controls within a single community (at the beginning and end of the study), no significant differences were observed in sample A, but a significant difference was seen in sample B. Insofar as T. trichiura is concerned, there were significant differences among controls in both samples. CONCLUSIONS: Only repeated and massive treatment significantly lowered the prevalence and intensity of A. lumbricoides infections during the study period.

El tratamiento antihelmíntico selectivo frente al tratamiento masivo: experiencia en dos comunidades hiperendémicas / Selective vs. mass treatment with antihelminthic drugs: experience in two hyperendemic communities

OBJETIVO: Evaluar la prevalencia e intensidad de las infecciones por geohelmintos en niños de dos comunidades hiperendémicas tratadas con técnicas antihelmínticas diferentes: una con tratamiento selectivo o individual, y la otra con tratamiento masivo reiterado. MÉTODOS: La población estuvo compuesta por 909 niños de uno u otro sexo, con edades entre 2 y 13 años, que vivían en dos comunidades marginales de la ciudad: Las Lomas y El Abasto, Santa Fe, Argentina. Se realizó un trabajo prospectivo longitudinal, cuasiexperimental, de comunidades. Durante los 22 meses del estudio se llevaron a cabo 5 controles parasitológicos, evaluados desde el punto de vista cualitativo y cuantitativo, y se dispensaron tratamientos antihelmínticos después de los controles 0, 2, 3 y 4. En Las Lomas se aplicó el tratamiento selectivo a los casos con diagnóstico parasitológico positivo que integraban la muestra A (n = 55) y en El Abasto, tratamiento masivo a todos los niños, incluidos los integrantes de la muestra B (n = 50). Ambas muestras fueron escogidas para realizar los controles. RESULTADOS: Se comprobó una prevalencia e intensidad de la infección por Ascaris lumbricoides significativamente mayor en El Abasto. No se detectaron diferencias para Trichuris trichiura. Al comparar las prevalencias y cargas parasitarias de A. lumbricoides entre los controles realizados dentro de una misma comunidad (inicio y final del estudio) no se observaron diferencias significativas en la muestra A, aunque sí en la muestra B. En cuanto a T. trichiura, se detectaron diferencias significativas entre ambos controles en las dos muestras. CONCLUSIONES: Solo el tratamiento masivo y reiterado logró disminuir eficaz y significativamente la prevalencia y la carga parasitaria de A. lumbricoides durante el período estudiado

Acción biológica de hongos contaminantes de alimentos para aves / Biological action of contaminating fungi of food for chickens

Se evaluó la acción de los hongos contaminantes de alimentos para aves, comercializados en la ciudad de Santa Fe, República Argentina, cuando se desarrollaron en dietas balanceadas para pollos. El 83,2% resultó inocuo, el 9,7% manifestó una acción depresora y el 7,1% restante estimuló el desarrollo de las aves. Las cepas que causaron muerte o depresión en el crecimiento resultaron ser productoras de, por lo menos, una de las siguientes micotoxinas: citrinina, patulina, zearalenona, esterigmatocistina, aflatoxinas, nigragilina y toxina TR-2

Prevalencia de helmintiosis intestinales en escolares de la ciudad de Santa Fe / Prevalence of intestinal helminthiasis in primary school children in Santa Fe city

The aims of this work were: 1.--to determine the intestinal helminth prevalence in children who live and attend primary schools in Santa Fe city. 2.--to characterize the socio-cultural and sanitary aspects of the children studied and consequently to group them in three supposed strata (hypo, meso and hyperendemic). The study was carried out during 1998. Considering the following variables: kind of streets, sewers and water supplies, parents' educational levels, satisfied or unsatisfied basic needs, the city was divided in three strata, according to the intestinal helminthic prevalence expected: 1--hypoendemic (< 25 percento), 2--mesoendemic (25-75 percento) and 3--hyperendemic (> 75 percento). Schools with children of both sexes, and ages between 5 and 13 who belonged to each one of the supposed strata, were identified. A direct parasitic examination and a Kato Katz technique were performed on a stool specimen of each selected child. An epidemiological survey was answered by the children's parents. The prevalence of helminths and geohelminths, with 95 percento confidence intervals, were respectively: total sample (n = 163). 36.2percento and 34.4 percento; stratum 1 (n1 = 60) 0 percento and 0 percento; stratum 2 (n2 = 70) 41 percento (29.9-52.9) y 38.6 percento (27.2-50.0) and stratum 3 (n3 = 33) 91 percento (81.1-100) and 87.9 percento (76.6-99.2). The above-mentioned variables, related to the socio-cultural and sanitary aspects, allowed to identify three well defined strata: hypoendemic, mesoendemic and hyperendemic, according to the different helminth prevalence detected among pupils who attend primary level school in Santa Fe city.