Abstract This study analysed the mycobiota on exoskeleton debris of the crab Neohelice granulata collected from an alkaline salt marsh and assessed the in vitro enzyme ability of selected isolates at different temperatures and pH. Exoskeleton fragments were incubated in moist chambers on paper and on agar medium. Growth and enzyme ability of selected fungi were also evaluated in agar media with 0.5 % casein, 1% Tween®20, and Chitin-Azure® by the production of a halo/growth ratio. We identified 22 fungal species using both methods. Since the two isolation methods added information to one another, both ones are necessary to recover the cultivable mycobiota associated with the exoskeleton debris. All fungi showed greater levels of enzyme activity in alkaline than acid medium with Tween®20. The halo diameter on casein and chitin varied according to the fungal isolate and pH. Most fungi had a larger halo at 4°C than at the other temperatures tested. Clonostachys rosea showed the greatest activity in all media at 4ºC. We conclude that exoskeletons of the N. granulata are a source of fungi able to produce enzyme activities that show differences upon incubation conditions to which they are cultivated such as ones including specific temperatures and pH values.

Arbuscular mycorrhizal fungi (AMF) increase the uptake of soluble phosphates, while phosphorus solubilizing fungi (S) promote solubilization of insoluble phosphates complexes, favoring plant nutrition. Another alternative to maintaining crop productivity is to combine minerals and rocks that provide nutrients and other desirable properties. The aim of this work was to combine AMF and S with pyroclastic materials (ashes and pumices) from Puyehue volcano and phosphate rocks (PR) from Rio Chico Group (Chubut) - to formulate a substrate for the production of potted Lactuca sativa. A mixture of Terrafertil®:ashes was used as substrate. Penicillium thomii was the solubilizing fungus and Rhizophagus intraradices spores (AMF) was the P mobilizer (AEGIS® Irriga). The treatments were: 1) Substrate; 2) Substrate + AMF; 3) Substrate+S; 4) Substrate + AMF+ S; 5) Substrate: PR; 6) Substrate: PR + AMF; 7) Substrate: PR + S and 8) Substrate: PR + AMF + S. Three replicates were performed per treatment. All parameters evaluated (total and assimilable P content in substrate, P in plant tissue and plant dry biomass) were significantly higher in plants grown in substrate containing PR and inoculas with S and AMF. This work confirms that the combination of S/AMF with Puyehue volcanic ashes, PR from the Río Chico Group and a commercial substrate promote the growth of L. sativa, thus increasing the added value of national geomaterials.

Los hongos micorrícicos arbusculares (HMA) incrementan la toma de fosfatos solubles, mientras que los hongos solubilizadores de fósforo (S) promueven la solubilización de complejos insolubles de fosfato, en conjunto benefician la nutrición de las plantas. La utilización de estos organismos en combinación con minerales o rocas que aportan nutrientes es otra alternativa para mantener la productividad de los cultivos. El objetivo de este trabajo fue combinar HMA y S con materiales piroclásticos (cenizas y pumicitas) del volcán Puyehue y rocas fosfóricas (RP) del Grupo Río Chico (Chubut) y evaluar el desempeno de estas mezclas como sustratos para la producción en maceta de Lactuca sativa. Para formular los sustratos, se utilizó como base una mezcla de Terrafertil® con cenizas. Penicillium thomii fue el S y esporas del hongo Rhizophagus intraradices (AEGIS® Irriga) sirvieron de fuente del HMA. Se evaluaron diversas combinaciones de microorganismos y la adición o no de RP. Los tratamientos fueron: 1) sustrato; 2) sustrato + HMA; 3) sustrato + S; 4) sustrato + HMA + S; 5) sustrato: RP; 6) sustrato: RP + HMA; 7) sustrato: RP + S, y 8) sustrato: RP+ HMA + S. Se efectuaron 3 repeticiones por tratamiento. Los parámetros evaluados fueron el contenido de P total y asimilable en el sustrato, el P en el tejido vegetal y la biomasa seca. Todos ellos fueron significativamente mayores en las plantas que crecieron en el sustrato adicionado con RP e inoculadas con S y HMA. Este trabajo confirma que la combinación S/HMA con cenizas volcánicas del Puyehue y las RP del Grupo Río Chico formuladas con un sustrato comercial promueven el crecimiento de L. sativa. De este modo es posible incrementar el valor agregado de geomateriales de origen nacional.

The aim of this work was to carry out a survey on the airborne fungal charge and other bioaerosols associated with a repository of mummified legacy from the Argentinian North West from the La Plata Museum. Two types of monitoring were performed: i) a viable and non viable aerobiological sampling in the exterior air of the repository, in the indoor air within the same and inside 3 cabinets containing human remains; and ii) a study and culture of the micobiota associated to the surface of materials with evident signs of biodeterioration. Based on the aerobiological sampling, the greatest diversity and spore concentration was registered in the outside environment, being Cladosporium cladosporioides, Alternaria sp. and Penicillium sp. the most representative taxa. Either inside the repository of the 3 cabinets, showed a particular fungal charge, the presence of Penicillium sp., Cladosporium sp. and Aspergillus sp. was characteristic. The analysis of contact samples makes evident the presence of Cladosporium herbarum, Penicillium frequentans and Talaromyces helicus. The knowledge of fungal microorganisms present in indoor environments is essential for heritage conservation and human health subjects.

El objetivo del trabajo fue llevar a cabo un relevamiento de la carga fúngica ambiental y otros bioaerosoles asociados a un depósito de restos momificados del NOA del Museo de La Plata. Se realizaron dos tipos de monitoreos, i) uno del tipo aerobiológico (viable y no viable) en el aire exterior del depósito, en el aire interior del mismo y en el interior de 3 de sus vitrinas donde se hallan restos humanos; y ii) otro que consistió en el estudio y cultivo de la micobiota asociada a la superficie de materiales con signos evidentes de deterioro. En base al muestreo aerobiológico, se registró la mayor diversidad y concentración esporal en el ambiente exterior siendo Alternaria sp., Cladosporium cladosporioides y Penicillium sp. los taxa más representativos. Aunque el interior del depósito como de cada vitrina analizada mostró una carga fúngica particular, la abundancia de las esporas correspondientes a Aspergillus sp., Cladosporium sp. y Penicillium sp. fue característica. El análisis de las muestras de contacto evidenció la presencia de Cladosporium herbarum, Penicillium frequentans y Talaromyces helicus en asociación a las momias analizadas. El conocimiento de los hongos presentes en ambientes interiores y sobre materiales de valor patrimonial constituye un elemento clave para el establecimiento de pautas de control para su conservación.

El hongo entomopatógeno Tolypocladium cylindrosporum ha sido estudiado como un agente de control biológico contra insectos de varios órdenes. Esta especie fue aislada del suelo, así como de insectos de los órdenes Coleoptera, Lepidoptera, Diptera e Hymenoptera. En el presente trabajo hemos analizado la capacidad de una cepa de T. cylindrosporum (LPSC Nº1065) aislada del suelo en Tierra del Fuego, Argentina, para producir enzimas hidrolíticas y determinar la relación de esta actividad con la patogenicidad del hongo para combatir la plaga de los áfidos en diferentes temperaturas (4º, 12º y 24ºC). En los ensayos de patogenicidad, siete días posteriores a la inoculación, se registró mortalidad en los adultos del áfido Ropalosiphum padi a diferentes temperaturas y también se demostró una amplia capacidad de crecer en varios medios de cultivos complementados con diferentes fuentes de carbono bajo las tres temperaturas de incubación ensayadas. Debido a su origen y a la tolerancia que tiene a bajas temperaturas esta cepa, presenta un gran potencial para su uso como agente de control biológico para las plagas de insectos de ambientes fríos y templados.

Tolypocladium cylindrosporum is an entomopathogenic fungi that has been studied as a biological control agent against insects of several orders. The fungus has been isolated from the soil as well as from insects of the orders Coleoptera, Lepidoptera, Diptera and Hymenoptera. In this study, we analyzed the ability of a strain of T. cylindrosporum, isolated from soil samples taken in Tierra del Fuego, Argentina, to produce hydrolytic enzymes, and to study the relationship of those activities to the fungus pathogenicity against pest aphids. We have made the traditional and molecular characterization of this strain of T. cylindrosporum. The expression of hydrolase activity in the fungal strain was estimated at three incubation temperatures (4ºC, 12ºC and 24ºC), on different agar media supplemented with the following specific substrates: chitin azure, Tween ® 20, casein, and urea for chitinase, lipase, protease, and urease activity, respectively. The hydrolytic-enzyme activity was estimated qualitatively according to the presence of a halo of clarification through hydrolase action, besides was expressed semi-quantitatively as the ratio between the hydrolytic-halo and colony diameters. The pathogenicity of the fungus was tested on adults of the aphid Rhopalosiphum padi at three temperatures of incubation (4ºC, 12ºC and 24ºC). The suspension was adjusted to a concentration of 1x10 7 conidia/ml. In pathogenicity assays at seven days post-inoculation, the fungus caused the mortality of adults of Ropalosiphum padi at different temperatures also showed a broad ability to grow on several agar-culture media, supplemented with different carbon sources at the three incubation temperatures tested. Although, the growth was greater with higher incubation temperatures (with maximum levels at 24°C), the fungus reached similar colony diameters after 15 days of incubation on the medium supplemented with Tween® 20 at the lower two incubation temperatures of 4°C or 12°C. In accordance with the results on colony diameters, the fungus revealed an ability to degrade casein, chitin derivatives, Tween® 20, and urea as evidenced by the appearance of a halo around the fungal colony. Because of its origin and temperature tolerance, this Argentine strain has great potential for use as a biocontrol agent for insect pest control in cold and temperate environments. Rev. Biol. Trop. 60 (2): 833-841. Epub 2012 June 01.

In this paper we analyze the diversity of species that compose the saprotrophic (anamorphic Ascomycota) fungi community in the leaf litter and soil in Celtis tala forest in Magdalena , located in the province of Buenos Aires . Seasonal samples were taken during two years (2004-2005), and fungi were isolated and identified. The relative frequencies of fungi were calculated. To compare the similarity of the fungi composition between different habitats, Sorensen's index of similarity (S´) was applied. The frequencies of occurrence of these fungi were recorded and Shannon Weaver index (H´) was applied to evaluate fungal diversity. A total of 104 taxa of anamorphic fungi were identified from which 54 were isolated from leaf litter, 58 from soil, and 8 species common for both types of substrate. From the taxa identified, those that had higher frequencies for leaf litter were the less represented in soil and vice versa. Sorensen´s index of similarity resulted 0.14, which means that the saprotrophic fungi community that grows in leaf litter of Celtis tala is composed by different species than those that characterized the mycobiota from the soil of the same area. Nevertheless, no significant differences were found in the index of diversity.

En el presente trabajo se analizó la diversidad de microhongos que constituyen la comunidad fúngica saprótrofa (anamorfos de Ascomycota) presente en hojarasca y suelo en bosques nativos de Celtis tala (tala) en el partido de Magdalena, provincia de Buenos Aires. Se realizaron muestreos estacionales durante dos años (2004-2005) y se aislaron e identificaron los hongos presentes. Se calculó la frecuencia relativa porcentual de cada taxón; estos datos fueron utilizados para evaluar la diversidad fúngica mediante el cálculo del Indice de Diversidad de Shanon y Weaver ( H '). Para discriminar las comunidades fúngicas se utilizó el coeficiente de similitud de Sorensen ( S '). Se identificaron 104 taxones de anamorfos de Ascomycota, de los cuales 54 fueron aislados de hojarasca y 58 de suelo, registrándose 8 especies en común para ambos tipos de muestra. De las especies compartidas, las que presentaron frecuencias más altas para hojarasca fueron las menos representadas en suelo y viceversa. El resultado del cálculo del coeficiente de similitud de Sorensen fue de 0.14, indicando que la comunidad de hongos saprótrofos que crece en la hojarasca de tala está integrada por diferentes especies a las que caracterizan la micobiota del suelo de la misma área. No se encontraron diferencias significativas en el índice de diversidad.