Caracterización biológica y molecular de un rhabdovirus causal de mosaico estriado amarillo, en maíz (Zea mays L.) en la provincia de Córdoba.

La familia Rhabdoviridae incluye varios patógenos económicamente importantes de cultivos, entre los más de 70 virus que afectan plantas. Estos últimos se clasifican en los géneros Cytorhabdovirus y Nucleorhabdovirus, dependiendo de si producen inclusiones en el espacio perinuclear, o si desarrollan viriones citoplasmáticos. Los integrantes de esta familia infectan gran cantidad de monocotiledóneas y dicotiledóneas y la mayoría son dependientes de transmisión por insectos. Las interacciones virus-vector son altamente específicas, y se ha registrado la replicación en insectos, del rhabdovirus que transmiten a las plantas. Cada especie de rhabdovirus induce un amplio espectro de síntomas en sus plantas huéspedes, y estos van desde la falta de efectos discernibles hasta la muerte total de la planta. El maíz (Zea mays L.) es el cultivo más ampliamente distribuido a nivel mundial y uno de los principales cultivos de cereales, ubicándose tercero en el ranking de producción en el mundo. En maíz se ha citado la presencia de varios rhabdovirus, entre estos American wheat striate mosaic virus (AWSMV), Cereal chlorotic mottle virus (CCMV), Maize mosaic virus (MMV), Maize sterile stunt virus (strains of Barley yellow striate virus), Northern cereal mosaic virus (NCMV) y Maize fine streak virus (MFSV). Ninguno de ellos reportado en Argentina. Desde 2001 un rhabdovirus es observado, por sintomatología y microscopía electrónica, en plantas de maíz de diferentes localidades de la provincia de Córdoba. Esta virosis pudo ser transmitida en dos oportunidades a plantas de maíz sanas mediante Peregrinus maidis y logró amplificarse mediante RT-PCR con iniciadores degenerados, el gen de la polimerasa L. Nuestra hipótesis es que el agente causal de la sintomatología de mosaico estriado amarillo en maíz sería un rhabdovirus emergente en Argentina, diferente de Maize mosaic virus (MMV), transmitido por delfácidos, que puede aislarse y mantenerse en condiciones controladas. El objetivo del presente trabajo es generar conocimientos biológicos, moleculares y epidemiológicos sobre el agente causal de la sintomatología en maíz de mosaico estriado amarillo. Para ello se colectarán plantas de maíz con sintomatología de mosaico estriado amarillo, en distintas localidades donde se presente la sintomatología. Las muestras se observarán al microscopio electrónico en cortes ultrafinos y en “leaf dip". Los viriones se purificarán, extraerá el RNA de los mismos, y obtendrá la secuencia de nucleótidos, para compararla con otras publicadas de virosis vegetales y se obtendrán homologías. Se realizarán transmisiones experimentales de esta virosis, por incisiones vasculares y mediante el empleo de diferentes especies de insectos vectores. Importancia del proyecto El avance de patógenos tropicales hacia zonas templadas es una de las causas de la aparición de las virosis emergentes, que se caracterizan por producir epifítias al ingresar a nuevos ecosistemas. El Maize mosaic virus (MMV) es un rhabdovirus que produce una de las virosis más importantes del maíz en el continente americano. Determinar la identidad del agente etiológico del mosaico estriado amarillo y establecer su relación con MMV es fundamental para desarrollar medidas proactivas y diseñar estrategias de manejo de esta nueva enfermedad.

Caracterización, procesamiento e industrialización del grano de quinoa, cultivado en la provincia de Córdoba - Argentina. Characterization, processing and industrialization of quinoa seed harvested in the province of Córdoba - Argentina

La quinoa (Chenopodium quinoa Willd), es un pseudocereal originario de la región Andina. Fue utilizada como alimento básico por los pueblos nativos. La quinoa, la papa y el maíz constituyeron el trinomio base de la alimentación indígena de este continente. La colonización española fue desplazando su cultivo a favor del trigo europeo y otros cereales, quedando reducida a las zonas altas de la región andina. La Quínoa ha adquirido una considerable atención en los últimos tiempos, principalmente por la calidad de sus proteínas y la ausencia de gluten en ella. Su empleo está ampliamente difundido en los países andinos, especialmente Bolivia y Perú, con un notable crecimiento de la superficie sembrada. En nuestro país la explotación de este cultivo se ubica principalmente en las provincias norteñas de Salta y Jujuy. En estos últimos años se ha reivindicado su cultivo y los granos privados de saponinas son considerados como un excelente alimento, reconocido por la OMS, la FAO y la NASA. Además de la calidad de sus lípidos y vitaminas, y al elevado contenido en almidón, la quinoa posee una proteína de excelente calidad nutricional y libre de gluten, lo que hace a este grano especialmente indicado para la alimentación de personas que sufren de la enfermedad celíaca o del síndrome de intestino irritado. El presente proyecto está orientado al aprovechamiento integral del grano de quinoa. Es nuestra intensión aquí, demostrar que dicho grano, cultivado en la provincia de Córdoba, permitirá elaborar productos alimenticios asi como también derivados de su industrialización. Para este objetivo se cuenta con las instalaciones de la Planta Piloto del Instituto de Ciencia y Tecnología de los Alimentos (ICTA), de la UNC, así como de intrumental moderno y acorde, como HPLC, GC, Espectrofotómetro UV-Vis, rotavapores de laboratorio e industrial, cámara fría, balanzas analíticas y de precisión, muflas, estufas, molinos y tamices, así como también, contamos con profesionales, algunos de ellos realizando su tesis doctoral en este tema. En cuanto a los objetivos que se persiguen, se espera obtener productos tales como sopas, papillas, productos para panadería y galletería y salsas. En el plano industrial, se pretende elaborar concentrados proteicos, almidón y saponinas. Como se dijo más arriba, a nivel internacional la quinoa ha comenzado a extender sus fronteras, y es así que hoy el principal productor mundial de este grano, Bolivia, destina un porcentaje importante de su producción a la exportación. La creciente demanda mundial de quinoa a hecho que se constituya en un cultivo estratégico y de alto valor, con precios internacionales que rondan los U$S 1200 la tonelada. Si a esto unimos que la planta presenta una gran resistencia a la sequía, que se adapta bien a terrenos salitrosos, arenosos y pobres, podemos comprender la importancia que adquiere para nuestra provincia, toda vez que en la misma existen zonas geográficas potencialmente aptas para su cultivo. Quinoa (Chenopodium quinoa Willd) is a pseudocereal originating in the Andean region. It was used as a staple food by native peoples. Quinoa, potatoes and corn were the tree most important indigenous staple food to this part of South America. Spanish colonization was marginalized cultivation in favor of European wheat and other grains, displacing it to the highlands of the Andean region. Quinoa has recently gained considerable attention, mainly by its protein quality and lack of gluten. Its use is widespread in the Andean countries, especially Bolivia and Peru, with a notable increase in plantings. In our country, the exploitation of this crop is located mainly in the northern provinces of Salta and Jujuy. In recent years its cultivation has been promoted, and the grains once free of saponins are considered an excellent food, recognized by WHO, FAO and NASA. In addition to its lipid and vitamins, and high starch contain, quinoa protein has an excellent nutritional value and it is free of gluten, making it particularly suitable for this grain to feed people with celiac disease or irritable bowel syndrome. This project aims at an integral development of quinoa grain. It is our intention here to demonstrate that this grain grown in the province of Córdoba, can produce food products resulting from local industrialization. This team has access to the facilities of the Pilot Plant of the Institute of Science and Food Technology (ICTA) of the UNC, and the modern equipments in it, as HPLC, GC, UV-Vis spectrophotometer, laboratory and industrial rotary evaporators, cold storage, analytical and precision balances, flasks, ovens, grinders and screens. Also, we have an important professional staff, some of them doing their thesis on this subject. With regard to the objectives pursued, we expect to obtain products such as soups, baby food, bakery products and biscuits and sauces. At the industrial level, it aims at producing protein concentrates, starch and saponins.

The design and development of heat extraction technologies for the utilisation of compost thermal energy

A composting Heat Extraction Unit (HEU) was designed to utilise waste heat from decaying organic matter for a variety of heating application The aim was to construct an insulated small scale, sealed, organic matter filled container. In this vessel a process fluid within embedded pipes would absorb thermal energy from the hot compost and transport it to an external heat exchanger. Experiments were conducted on the constituent parts and the final design comprised of a 2046 litre container insulated with polyurethane foam and kingspan with two arrays of qualpex piping embedded in the compost to extract heat. The thermal energy was used in horticultural trials by heating polytunnels using a radiator system during a winter/spring period. The compost derived energy was compared with conventional and renewable energy in the form of an electric fan heater and solar panel. The compost derived energy was able to raise polytunnel temperatures to 2-3°C above the control, with the solar panel contributing no thermal energy during the winter trial and the electric heater the most efficient maintaining temperature at its preset temperature of 10°C. Plants that were cultivated as performance indicators showed no significant difference in growth rates between the heat sources. A follow on experiment conducted using special growing mats for distributing compost thermal energy directly under the plants (Radish, Cabbage, Spinach and Lettuce) displayed more successful growth patterns than those in the control. The compost HEU was also used for more traditional space heating and hot water heating applications. A test space was successfully heated over two trials with varying insulation levels. Maximum internal temperature increases of 7°C and 13°C were recorded for building U-values of 1.6 and 0.53 W/m2K respectively using the HEU. The HEU successfully heated a 60 litre hot water cylinder for 32 days with maximum water temperature increases of 36.5°C recorded. Total energy recovered from the 435 Kg of compost within the HEU during the polytunnel growth trial was 76 kWh which is 3 kWh/day for the 25 days when the HEU was activated. With a mean coefficient of performance level of 6.8 calculated for the HEU the technology is energy efficient. Therefore the compost HEU developed here could be a useful renewable energy technology particularly for small scale rural dwellers and growers with access to significant quantities of organic matter

Comparação de Proteínas: alimentação das aves I

Beginning an experiment on protein comparisons, at the Poultry and Rabbitry Departament of the Esc. Sup. de Agricultura "Luiz de Queiroz", University of S. Paulo, four groups of growing chicks were submitted during 40 days to the following rations: basal part - 50 corn meal and 30 wheat bran, variable part - R1 - 10 tankage and 10 peanut meal, R2 - 10 tankage and 10 cottonseed meal, R3 - 7 peanut meal, 7 cocoanut meal and 7 cottonseed meal, R4 - 5 tankage, 5 peanut, 5 cocoanut and 5 cottenseed meal, R2 and R3 gave results which may be considered as equal and inferior than those obtained with the others, R4 being the best one. The statistical analises showed no significant differences.

Substituição do farelo de trigo pelo farelo de sabugo de milho

Two 50 R. I. R. chicken groups were contrasted, both receiving the same basic-ration differing only in the content of wheat bran or corn cobs meal. One ration had 10% of wheat bran and in the other one the 10% of wheat bran has been substituted by 10% of corn cobs meal. It was found on the final weight a significant advantage of 12,8% with wheat bran. However, the development of chikens receiving corn cobs meal was quite normal.

Pesquisas sôbre a análise estatística de experiências de adubação com o auxílio da lei de Mitscherlich

Statistical analyses of an experiment on wheat were carried out with the aid of Mitscherlich's law. The experiment was made in Ponta Grossa, Paraná, by the Ministry of Agriculture of Brasil. Lime, in the form of Ca(OH)2, was applied at the levels of 0, 2, 4, 6 and 8 metric tons per hectare. A 5 x 5 Latin square was used. Lime was applied in 1940 and wheat was cultivated in the same plots for several years. The following fertilizers were annually used for all plots: NaNO3 100 kilograms per hectare, Superphosphate 350 kilograms per hectare, K2S04 80 kilograms per hectare. The statistical analysis of the data collected in 1941, 1942, 1943, 1947 and 1948, carried out in accordance with the methods previously introduced by Pimentel Gomes and Malavolta (1949 a, 1949 b) and Pimentel Gomes (1950), proved: I. That Mitscherlich's law could be correctly applied to the data. II. That there was a statistically significant effect of lime on wheat yield. III. That the optimum amount of lime to be applied to the soil lies between 5 and 15 hundred kilograms of Ca(OH)2 per hectare. IV. That there is a migration of calcium from some plots to others, in such a way that the data obtained in 1947 and 1948 are not representative of the amounts of lime applied in 1940. V. That the analysis of variance can be used, as the Bartlett test shows that the variances at the distinct levele of lime application are not statistically different. It must be noted that, with improved variety and fertilization, the yield was rised to about 2500 kilograms per hectare in 1947, and 1600 in 1948, being only of about 100 kilograms per hectare in 1940.

A raspa de mandioca como sucedâneo dos farelos de trigo na alimentação de pintos

In a feeding trial cassava root meal was used as a substitute for wheat bran and wheat middling (mixed) in several ranges: 10, 15, 20 and 30% of a ration. Five groups of 32 seven day old Rhode I. Red chicks were used during 6 weeks of the trial. The results are shown in the Tables (Quadros) I, II and III. Table I shows an high mortality in R4, receiving 30% of cassava root meal and no wheat by product. It was observed a depression of the development of the chicks that was so much high as the proportion of the cassava meal increased in the ration consumed. The A. suggests cassava root meal might have an antagonistic factor acting as a "toxic", that he imagine could be corrected by a higher vitaminic and mineral proportion. This hipothesis must be investigated.

O farelinho de trigo fermentado com Bacta-Mon e excremento de vaca na alimentação de pintos

Bacta-mon, produced by Bacta-mon S. A., São Paulo, Brazil, is recommended as a microbiological, and suggested as a supplement for animal rations. This experiment deals with this product in chicken feeding. Four lots of baby chicken received, during 6 weeks the following treatments: a control ration Rl; a ration R2 containing 10 per cent of wheat standard middlings fermented by Bacta-mon, substituting equal weight of wheat standard middlings of the control ration Rl; two rations R3 and R4, both without meat meal and containing 10 per cent of wheat standard middlings fermented respectively by Bactamon and fresh cow manure, substituting equal weight of wheat standard middlings of the control. The results may be so summarized: (1) On the basis of the weights of the chicks at 6 weeks age, we concluded that there was not any advantage in the addition of the wheat standard middlings fermented by Bacta-mon. (2) The rations R3 and R4 were considered statistically equivalents and lower the control ration Rl. (3) It seems that the main difference observed in these results may be atributed to lack of animal protein. (4) The highest mortality and the lowest consumption of feed by the lots receiving ration R3 and R4, seem to indicate, in addition, that this prejudice was due the lack of animal protein and the unpalatability of these rations.

Substituição de subprodutos de trigo pelo sorgo moído na alimentação de pintos

Searching for a substitute of wheat bran and wheat standard middlings in chick mashes, three experiments were carried out using ground sorghums. In the first one, 30% of Atlas, Kafir e White Afrikan x Sumac (seed chops) were substituted for 30% of wheat by-products. All the rations with sorghum grain gave inferior results. In another experiment, 7, 14, 20 and 30% of sorghum substituted equal percentages of those wheat by-products, the best results having been obtained with 7% of Atlas and 23% of wheat by-products. Finally, in a third experiment, 5% of dried cow manure plus 10, 20 and 30% of ground Atlas sorghum were substituted for 5% of alfalfa hay meal plus, respectively, 10, 20 and 30% of wheat by-products. All results obtained from rations containing sorghum were as good as or better than that given by the ration including alfalfa hay meal and only wheat by-products. Under the conditions of this experiment, 5% of cow manure plus 12,25% of sorghum and 17,75% of wheat by-products is supposed to be the best combination to be recommended, this result having been attained through the study of the regression equation.

The diet of the black widow spider Latrodectus mirabilis (Theridiidae) in two cereal crops of central Argentina

The spider Latrodectus mirabilis (Holmberg, 1876) is commonly found in cereals crops of central Argentina. We studied its diet composition at the field and capture rate on leaf-cutting ants based on laboratory experiments. This study comprises the first approach that documents the diet of L. mirabilis in wheat and oat fields of central Argentina. We identified 1,004 prey items collected from its webs during the last phenological stages of both cereal crops. The prey composition was variable but the spiders prey mainly on ants (Formicidae, Hymenoptera), who represented more than 86% of the total. Meanwhile, in the capture rate experiences we registered a high proportion of ants captured by spiders at the beginning of experiences, capturing the half of the ants from total in the first four hours. Summarizing, we reported a polyphagous diet of this spider species in wheat and oat fields. Ants were the most important prey item of this spider, as found in other Latrodectus spiders around the world.

Allergic asthma to thaumatin : case report

Background: Thaumatin is a protein originally isolated from an African fruit (the "katemfe"), but various thaumatin-like proteins have been found in apples, grapes, kiwis and olives, etc. Thaumatin has natural sweetening properties and is about 2000 to 3000 times more potent than sucrose. It is therefore used in the food industry, particularly in the processing of low-calories sweeteners. Recently, thaumatin-like proteins have been described as a new family of allergens. Methods: We report the case of a 44-year-old woman occupationally exposed to thaumatin, who developed an allergy to it. The first symptom was an urticaria, which she presented two years after the factory she was working in (a sweeteners manufacturer), started to use thaumatin. Later on, she perceived an acute episode of a sensation of lump in the throat, persisting mild dyspnea, dysphonia and cough. Despite normal peak flow values and a normal chest examination, her general practitioner treated her with local corticoids and systemic antihistaminic drugs, which improved the symptoms. As occupational physicians, we were asked about the likelihood of an occupational disease. We visited her working place, and assessed the exposure to thaumatin. We concluded that the probability for a delayed asthma related to a thaumatin exposure was high, despite the lack of an exposure test. Results: The case was submitted to the insurance company as an occupational disease, and was accepted as such. It was therefore decided not to perform the exposure test, given the absence of true benefit for the patient, who was advised to switch job, and to avoid any exposure to thaumatin in the future. A few months later, the symptoms had completely disappeared. Conclusion: Some molecules only used in specific industry sectors, can cause health problems, such as allergy, but also toxic impairments, etc. The occupational physician, trained to find out which products and identify which molecules are involved, can contribute to the diagnosis, and help make possible a safe return to work for the patient.

Seroprevalence of Trypanosoma cruzi Infection in Students at the Seven-Fourteen Age Range, Londrina, PR, Brazil, in 1995

Seropositivity for Chagas disease was evaluated in 834 children aged between 7 and 14 from the Municipal Teaching System in the district of Londrina, State of Paraná. A seroprevalence rate of 0.1% was found through the use of an indirect immunofluorescent test and an enzyme-linked immunosorbent assay. This low rate of seroprevalence provides evidence that the vectorial transmission of Chagas disease has been eliminated in Londrina. The main reason for the elimination of vectorial transmission of Trypanosoma cruzi infection, as evaluated by serological tests, may be a remarkable change in the economic structure of the northern region of Paraná in the 1960's. At that time coffee production was almost completely replaced by soy beans, wheat and grazing in the rural areas. This change deeply affected the rural ecology and caused an exodus of the population from rural to urban areas as well as a decrease in the total number of the population of that region. The measures introduced for controlling the disease through the Program of Chagas Disease Control established by the Fundação Nacional de Saúde of the Brazilian Ministry of Health, certainly, had a positive impact on the reduction of American trypanosomiasis prevalence in the area under study. However, it does not seem that this was the most relevant factor responsible for the elimination of vectorial transmission of Chagas disease in Londrina.

Predominance of Nonculturable Cells of the Biocontrol Strain Pseudomonas fluorescens CHA0 in the Surface Horizon of Large Outdoor Lysimeters.

The persistence of the biocontrol agent Pseudomonas fluorescens CHA0 in the surface horizon of 12 large outdoor lysimeters planted with winter wheat, Phacelia tanacetifolia followed by spring wheat, or maize was monitored for 1 year. Soil was inoculated with a spontaneous rifampin-resistant mutant (CHA0-Rif) of CHA0, and the strain was studied by using colony counts, Kogure's direct viable counts, and total counts (immunofluorescence). The number of culturable cells of the inoculant decreased progressively from 8 to 2 log CFU/g of soil or lower. However, culturable cells of CHA0-Rif accounted for less than 1% of the total cells of the inoculant 8 months after release in autumn. Since viable but nonculturable cells represented less than a quarter of the latter, most cells of CHA0-Rif in soil were thus inactive-dormant or dead at that time. Nonculturable cells of the inoculant were predominant also in the surface horizon of the lysimeters inoculated in the spring, and a significant fraction of them were viable. Results suggest that the occurrence of nonculturable cells of CHA0-Rif was influenced by climatic factors (water availability and soil temperature) and the abundance of roots in soil. The fact that the inoculant persisted as mixed populations of cells of different physiological states, in which nonculturable cells were predominant, needs to be taken into account when assessing the autecology of wild-type or genetically modified pseudomonads released into the soil ecosystem.

New aspects in celiac disease

Celiac disease (CD) is a common autoimmune disorder characterized by an immune response to ingested gluten and has a strong HLA association with HLA-DQ2 and HLA-DQ8 molecules, but human HLA-DQ risk factors do not explain the entire genetic susceptibility to gluten intolerance. CD is caused by the lack of immune tolerance (oral tolerance) to wheat gluten. In this sense, the expression of soluble HLA-G in CD is of special interest because the molecule plays an important role in the induction of immune tolerance. The enhanced expression of soluble HLA-G found in CD may be part of a mechanism to restore the gluten intolerance. In this editorial, we review recent progress in understanding CD in relation to its prevalence, diagnosis and possible mechanisms of pathogenesis.

Pyoluteorin production by Pseudomonas fluorescens strain CHA0 is involved in the suppression of Pythium damping-off of cress but not of cucumber

Pseudomonas fluorescens strain CHA0 is an effective biocontrol agent of various soilborne pathogens. It controls damping-off or root rot caused byPythium ultimum on cucumber, wheat and cress. Strain CHA0 synthesizes several antibiotic metabolites such as hydrogen cyanide, 2,4-diacetylphloroglucinol, and pyoluteorin. The role of pyoluteorin in the suppression of damping-off was investigated. Two Tn5 mutants (CHA660 and CHA661) of strain CHA0 were isolated which had lost the capacity to produce pyoluteorin but still produced 2,4-diacteylphloroglucinol and HCN. These mutants still inhibitedP. ultimum on malt agar (which favours the production of 2,4-diacetylphloroglucinol) but had partially lost the ability to inhibit this pathogen on King's B agar (which favours the production of pyoluteorin). The two pyoluteorin-negative mutants showed a reduced capacity to suppress damping-off of cress caused byP. ultimum but were as effective in the protection of cucumber against this pathogen as the wild-type strain. These results indicate that, depending on the plant, pyoluteorin production plays a role in the suppression of damping-off by strain CHA0 without being a major mechanism in disease suppression. We suggest that the contribution of pyoluteorin to the biocontrol activity of strain CHA0 is determined by the quantity of this antibiotic produced in the rhizosphere, which might depend on the root exudates of the host plant.