[Detection of genetic variability in Cercospora kikuchii isolates from a single soybean field]. / Detección de variabilidad genética en aislamientos de Cercospora kikuchii contaminantes de un mismo sembradío de soja.

Detection of genetic variability in Cercospora kikuchii isolates from a single soybean field. Current knowledge about epidemiology and population structure of Cercospora kikuchii is little developed and no studies regarding this subject have been reported in Argentina. The aim of this work was to select primers to study genetic variability in C. kikuchii isolated from the same soybean field using RAPD (Random Amplified Polymorphism DNA). RAPD was applied to the DNA of 5 C. kikuchii, isolated from diseased tissue of the soybean in the same field, another isolate, from a strain collection. Out of seven primers, five of them proved to be useful to study the population of C. kikuchii isolates.

Detección de variabilidad genética en aislamientos de Cercospora kikuchii contaminantes de un mismo sembradío de soja / Detection of genetic variability in Cercospora kikuchii isolates from a single soybean field

El conocimiento de la epidemiología y la estructura poblacional de Cercospora kikuchii está poco desarrollado y no se han comunicado estudios al respecto en la Argentina. El objetivo de este trabajo fue seleccionar oligonucleótidos que permitan detectar variabilidad genética en aislamientos de C. kikuchii obtenidos a partir de soja proveniente de un mismo sembradío, mediante la aplicación de RAPD. Se trabajó con 6 aislamientos de C. kikuchii, 5 de ellos se obtuvieron a partir de trozos de tejido enfermo y el restante provenía de una colección de cultivos. De los 7 oligonucleótidos empleados, 5 resultaron útiles para el estudio poblacional de los aislamientos de C. kikuchii.

Current knowledge about epidemiology and population structure of Cercospora kikuchii is little developed and no studies regarding this subject have been reported in Argentina. The aim of this work was to select primers to study genetic variability in C. kikuchii isolated from the same soybean field using RAPD (Random Amplified Polymorphism DNA). RAPD was applied to the DNA of 5 C. kikuchii, isolated from diseased tissue of the soybean in the same field, another isolate, from a strain collection. Out of seven primers, five of them proved to be useful to study the population of C. kikuchii isolates.

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 Kupffer's 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.

[The action of different coagulants to remove Cryptosporidium during the process of water treatment]. / Acción de distintos coagulantes para la eliminación de Cryptosporidium spp. en el proceso de potabilización del agua.

Cryptosporidium is one of the microorganisms of main concern from the point of view of Public Health, being a priority problem for water treatment plants and water regulatory institutions. Due to its small size and resistance to chlorination, Cryptosporidium removal during the process of drinking water treatment is a hard task. The effectiveness of different coagulants commonly used in the process of removal of oocysts was analyzed. The technique used was the Jar Test. It was found that: 1) coagulants with the addition of polimeric coadjuvants produce over 2 logs of oocyst removal; 2) a low value in turbidity does not necessarily mean optimal parasite removal, and 3) the addition of polyelectrolites to ferric chloride diminishes variability, both in final turbidity and Cryptosporidium removal.

Acción de distintos coagulantes para la eliminación de Cryptosporidium spp. en el proceso de potabilización del agua / The action of different coagulants to remove Cryptosporidium during the process of water treatment

Cryptosporidium es uno de los microorganismos de mayor interés desde el punto de vista de la Salud Pública y constituye un problema prioritario para las plantas y organismos reguladores de agua. Debido a su pequeño tamaño y a su resistencia a la cloración, la eliminación por el proceso de potabilización es una tarea compleja. En este trabajo se analizó la efectividad de distintos coagulantes utilizados comúnmente en tal proceso para lograr la remoción de los ooquistes. Se trabajó con la prueba de jarras (Jar Test). Se halló que: 1) Los coagulantes con agregado de polímeros coadyuvantes producen remociones de ooquistes superiores a 2 log. 2) Un valor bajo de turbiedad no asegura una remoción óptima de los parásitos. 3) La adición de polielectrolitos al cloruro férrico disminuye la variabilidad tanto en la turbiedad final como en la eliminación de Cryptosporidium.

Cryptosporidium is one of the microorganisms of main concern from the point of view of Public Health, being a priority problem for water treatment plants and water regulatory institutions. Due to its small size and resistance to chlorination, Cryptosporidium removal during the process of drinking water treatmentis a hard task. The effectiveness of different coagulants commonly used in the process of removal of oocysts was analyzed. Thetechnique used was the Jar Test. It was found that: 1) coagulants with the addition of polimeric coadjuvants produce over 2 logs of oocyst removal; 2) a low value in turbidity does not necessarily mean optimal parasite removal, and 3) the addition of polyelectrolites to ferric chloride diminishes variability, both in final turbidity and Cryptosporidium removal.

[Cryptosporidium y Giardia in surface water]. / Cryptosporidium y Giardia en aguas superficiales.

The aim of this work was to determine Giardia and Cryptosporidium levels in surface water used either as recreational or drinking water source, and to estimate the relationship with bacteriological and physicochemical parameters determining water quality. This study was carried out during 22 months, in Santa Fe and Santo Tomé cities (Santa Fe Province, Argentina). Cryptosporidium from 100% of the recreational samples (44-2404 oocysts/100 l) and from 92% of water sources (< 20-539 oocysts/100 l) was detected, while Giardia was found in lower concentrations and frequencies: 72% (< 20-670 cysts/100 l) and 31% (< 20-65 cysts/100 l), respectively. Statistically significant relationships were found between these parasites and organic matter, turbidity and bacteriological indicators of contamination (Escherichia coli, streptococci, Enterococcus spp, Pseudomonas aeruginosa). These relationships, however, vary according to the sampling place, the source and levels of contamination.

Cryptosporidium y Giardia en aguas superficiales / Cryptosporidium y Giardia in surface water

The aim of this work was to determine Giardia and Cryptosporidium levels in surface water used either as recreational or drinking water source, and to estimate the relationship with bacteriological and physicochemical parameters determining water quality. This study was carried out during 22 months, in Santa Fe and Santo TomÚ cities (Santa Fe Province, Argentina). Cryptosporidium from 100 of the recreational samples (44-2404 oocysts/100 l) and from 92 of water sources (< 20-539 oocysts/100 l) was detected, while Giardia was found in lower concentrations and frequencies: 72 (< 20-670 cysts/100 l) and 31 (< 20-65 cysts/100 l), respectively. Statistically significant relationships were found between these parasites and organic matter, turbidity and bacteriological indicators of contamination (Escherichia coli, streptococci, Enterococcus spp, Pseudomonas aeruginosa). These relationships, however, vary according to the sampling place, the source and levels of contamination.

[Toxic activity of Penicillium citrinum metabolites on Mus musculus mice]. / Actividad de metabolitos de Penicillium citrinum sobre ratones Mus musculus.

The aims of this work were to study the influence of secondary metabolites produced by a Penicillium citrinum strain. Mus musculus mice were fed with a diet containing those metabolites to determine both its influence on their development and the pathological and biochemical changes on experimental animals. Male and female including pregnant females, were studied. One group received commercial feed (A.B.) to which the citrinin- producing mould had been added (LF), another received A.B. contaminated with commercial citrinin (LC). The last group received noncontaminated feed (LT). The animals were weighed weekly, and sacrificed after sixty days, so that they could be studied both macro and microscopically. In LF and LT mice, haematological analysis was carried out and hemosiderin was looked for in urine. The diet of the newborne mice, after weaning, was identical to that of their parent. The treated animals (LF and LC) showed morphological alterations, a significant decrease in weight and morphologic alterations and hemosiderin granules were detected in some of their organs. In LT all breeds survived, none of the mice showed neither macro nor microscopic anomalies and had normal biochemical parameters. Fewer breeds in LF survived, male infertility was detected and some of their haematologic parameters were also measurably lower.

[Cryptosporidium and water]. / Cryptosporidium y agua.

During the last years, cryptosporidiosis has been recognized as an important cause of diarrheal disease. According to different references, water has been an important vehicle responsible for the transmission in many epidemic outbreaks. The high number of oocysts eliminated by human and animal hosts, as well as low infectious dose and its resistance to desinfectants are some factors which contribute to the infectious risk. It has been also pointed that bacteriologically acceptable water may contain parasites. In order to minimize such risks, it is desirable to protect the water supplies and to use multiple barriers (coagulation, sedimentation and filtration) in drinking water treatment. The aim of this work is to provide information about the different aspects conditioning the presence of Cryptosporidium in drinking water.

Cryptosporidium y agua / Cryptosporidium and water

During the last years, cryptosporidiosis has been recognized as an important cause of diarrheal disease. According to different references, water has been an important vehicle responsible for the transmission in many epidemic outbreaks. The high number of oocysts eliminated by human and animal hosts, as well as low infectious dose and its resistance to desinfectants are some factors which contribute to the infectious risk. It has been also pointed that bacteriologically acceptable water may contain parasites. In order to minimize such risks, it is desirable to protect the water supplies and to use multiple barriers (coagulation, sedimentation and filtration) in drinking water treatment. The aim of this work is to provide information about the different aspects conditioning the presence of Cryptosporidium in drinking water.

Aislamiento, identificación y determinación de la capacidad toxicogénica de hongos contaminantes de cereales y productos alimenticios / Isolation, identification and determination of the toxicogenic capacity of fungi contaminating cereals and alimentary products

Se determinó en la ciudad de Santa Fe y su zona de influencia, la capacidad toxicogénica, mediante la aplicación de ensayos biológicos rápidos, a hongos contaminantes de cereales y productos alimenticios elaborados con ellos. Los alimentos estudiados fueron: soja, maíz, trigo y sus derivados: los géneros frecuentes aislados fueron: aspergillus, penicillium y fusarium, identificandose las especies de aquellos que resultaron toxicogénicos. Las acciones citotóxicas detectadas mediante los ensayos aplicados fueron: capacidad mutagénica, hemólisis de glóbulos rojos humanos y elongación e inhibición de células de bacillus thuringiensis