Mycobiota on exoskeleton debris of Neohelice granulata in an alkaline-sodic salt marsh: in vitro enzyme ability at different temperatures and pH.

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.

[Combination of phosphorus solubilizing and mobilizing fungi with phosphate rocks and volcanic materials to promote plant growth of lettuce (Lactuca sativa L.)]. / Combinación de hongos movilizadores y solubilizadores de fósforo con rocas fosfóricas y materiales volcánicos para la promoción del crecimiento de plantas de lechuga (Lactuca sativa L.).

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.

Fungal monitoring of the indoor air of the Museo de La Plata Herbarium, Argentina / Muestreo de los hongos del aire en el interior del Herbario del Museo de La Plata, Argentina

Background. Biological agents, such as fungal spores in the air in places where scientific collections are stored, can attack and deteriorate them. Aims. The aim of this study was to gather information on the indoor air quality of the Herbarium of Vascular Plants of the Museo de Ciencias Naturales de La Plata, Argentina, in relation to fungal propagules and inert particles. Methods. This study was made using a volumetric system and two complementary sampling methods: (1) a non-viable method for direct evaluation, and (2) a viable method by culture for viable fungal propagules. Results. The non-viable method led to ten spore morphotypes being found from related fungal sources. A total of 4401.88 spores/m3 and 32135.18 inert suspended particles/m3 were recorded. The viable method led to the finding of nine fungal taxa as viable spores that mostly belonged to anamorphic forms of Ascomycota, although the pigmented yeast Rhodotorula F.C. Harrison (Basidiomycota) was also found. A total count of 40,500 fungal CFU/m3 air was estimated for all the sites sampled. Conclusions. Both the non-viable and viable sampling methods were necessary to monitor the bio-aerosol load in the La Plata Herbarium. The indoor air of this institution seems to be reasonably adequate for the conservation of vascular plants due to the low indoor/outdoor index, low concentrations of air spores, and/or lack of indicators of moisture problems (AU)

Antecedentes. Los agentes biológicos, tales como las esporas fúngicas suspendidas en el aire, en sitios donde se conservan colecciones científicas, pueden dar lugar al ataque y deterioro de las mismas por los hongos. Objetivos. El objetivo de este trabajo fue proporcionar información acerca de la calidad del aire interior en el Herbario de Plantas Vasculares del Museo de Ciencias Naturales de La Plata, Argentina, en relación con el contenido de propágulos fúngicos y partículas inertes, mediante el uso de dos técnicas complementarias. Métodos. El estudio se llevó a cabo con un sistema volumétrico y dos metodologías de muestreo: 1) método no viable de evaluación directa; y 2) método viable para el cultivo de propágulos fúngicos viables. Resultados. A partir del sistema de recuperación directa se cuantificó un total de 4401,88 esporas/m3 con 10 morfotipos pertenecientes en su mayoría a anamorfos de Ascomycota. Asimismo se cuantificaron 32135,18 partículas inertes suspendidas por m3. Con el uso del sistema viable se estimó un total de 40.500UFC/m3 aire para todos los sitios muestreados y se identificaron nueve taxa fúngicos que pertenecen también a formas anamórficas de Ascomycota, aunque se halló la levadura pigmentada Rhodotorula F.C. Harrison (Basidiomycota). Conclusiones. Ambos métodos, viable y no viable de muestreo, son necesarios para el control de la carga de aerosoles en el Herbario de La Plata. El aire interior de esta institución parece razonablemente adecuado para la conservación de plantas vasculares, dado el bajo índice interior/exterior, bajas concentraciones de esporas o la ausencia de indicadores de problemas de humedad (AU)

Fungal monitoring of the indoor air of the Museo de La Plata Herbarium, Argentina.

BACKGROUND: Biological agents, such as fungal spores in the air in places where scientific collections are stored, can attack and deteriorate them. AIMS: The aim of this study was to gather information on the indoor air quality of the Herbarium of Vascular Plants of the Museo de Ciencias Naturales de La Plata, Argentina, in relation to fungal propagules and inert particles. METHODS: This study was made using a volumetric system and two complementary sampling methods: (1) a non-viable method for direct evaluation, and (2) a viable method by culture for viable fungal propagules. RESULTS: The non-viable method led to ten spore morphotypes being found from related fungal sources. A total of 4401.88spores/m3 and 32135.18 inert suspended particles/m3 were recorded. The viable method led to the finding of nine fungal taxa as viable spores that mostly belonged to anamorphic forms of Ascomycota, although the pigmented yeast Rhodotorula F.C. Harrison (Basidiomycota) was also found. A total count of 40,500fungal CFU/m3 air was estimated for all the sites sampled. CONCLUSIONS: Both the non-viable and viable sampling methods were necessary to monitor the bio-aerosol load in the La Plata Herbarium. The indoor air of this institution seems to be reasonably adequate for the conservation of vascular plants due to the low indoor/outdoor index, low concentrations of air spores, and/or lack of indicators of moisture problems.

Preliminary data on growth and enzymatic abilities of soil fungus Humicolopsis cephalosporioides at different incubation temperatures / Datos preliminares sobre el crecimiento y la capacidad enzimática del hongo de suelo Humicolopsis cephalosporioides a diferentes temperaturas de incubación

Background. Nothofagus pumilio (Poepp & Endl.) Krasser, known as 'lenga' is the most important timber wood species in southernmost Patagonia (Argentina). Humicolopsis cephalosporioides Cabral & Marchand is a soil fungus associated with Nothofagus pumilio forests, which has outstanding cellulolytic activity. However, there is no information about the ability of this fungus to use organic substrates other than cellulose, and its ability to produce different enzyme systems, as well as its response to temperature. Aims. The aim of this study was to examine the role of H. cephalosporioides in degradation processes in N. pumilio forests in detail by evaluating the in vitro ability of four isolates of this fungus to grow and produce different lytic enzyme systems, and their response to incubation temperature. Methods. The ability of the fungi to grow and produce enzyme systems was estimated by inoculating them on agar media with specific substrates, and the cultures were incubated at three temperatures. Results. A differential behavior of each strain in levels of growth and enzyme activity was found according to the medium type and/or incubation temperature. Conclusions. A intra-specific variability was found in H. cephalosporioides. Likewise a possible link between the saprotrophic role of this fungus in N. pumilio forests and the degradation of organic matter under stress conditions, such as those from frosty environments, was also discussed (AU)

Antecedentes. Nothofagus pumilio (Poepp & Endl) Krasser (N. pumilio), conocido como «lenga», es la especie maderable más importante en el extremo sur de Patagonia (Argentina). Humicolopsis cephalosporioides Cabral & Marchand es un hongo del suelo asociado a bosques de N. pumilio, que tiene una actividad celulolítica excepcional. Sin embargo, no hay información acerca de la capacidad de este hongo para utilizar otros sustratos orgánicos distintos de la celulosa, o para producir diferentes sistemas enzimáticos, así como su respuesta a la temperatura. Objetivos. El objetivo de este estudio fue profundizar en el rol que Humicolopsis cephalosporioides tiene en los procesos de degradación en los bosques de N. pumilio a través de la evaluación de la capacidad in vitro de 4 aislamientos de este hongo para crecer y producir diferentes sistemas enzimáticos líticos y su respuesta a la temperatura de incubación. Métodos. La capacidad de los hongos para crecer y producir sistemas enzimáticos se estimó a través de su inoculación sobre medios de agar con sustratos específicos, siendo incubados a 3 temperaturas. Resultados. Se observó un comportamiento diferencial de cada cepa en el crecimiento y la actividad enzimática de acuerdo con el tipo de medio o la temperatura de incubación. Conclusiones. Se observó variabilidad intraespecífica en Humicolopsis cephalosporioides. Asimismo, se discutió la posible relación entre el rol saprotrófico de este hongo en los bosques de N. pumilio y la degradación de la materia orgánica en condiciones estresantes, como las existentes en ambientes fríos (AU)

Preliminary data on growth and enzymatic abilities of soil fungus Humicolopsis cephalosporioides at different incubation temperatures.

BACKGROUND: Nothofagus pumilio (Poepp & Endl.) Krasser, known as "lenga" is the most important timber wood species in southernmost Patagonia (Argentina). Humicolopsis cephalosporioides Cabral & Marchand is a soil fungus associated with Nothofagus pumilio forests, which has outstanding cellulolytic activity. However, there is no information about the ability of this fungus to use organic substrates other than cellulose, and its ability to produce different enzyme systems, as well as its response to temperature. AIMS: The aim of this study was to examine the role of H. cephalosporioides in degradation processes in N. pumilio forests in detail by evaluating the in vitro ability of four isolates of this fungus to grow and produce different lytic enzyme systems, and their response to incubation temperature. METHODS: The ability of the fungi to grow and produce enzyme systems was estimated by inoculating them on agar media with specific substrates, and the cultures were incubated at three temperatures. RESULTS: A differential behavior of each strain in levels of growth and enzyme activity was found according to the medium type and/or incubation temperature. CONCLUSIONS: A intra-specific variability was found in H. cephalosporioides. Likewise a possible link between the saprotrophic role of this fungus in N. pumilio forests and the degradation of organic matter under stress conditions, such as those from frosty environments, was also discussed.

Pathogenic and enzyme activities of the entomopathogenic fungus Tolypocladium cylindrosporum (Ascomycota: Hypocreales) from Tierra del Fuego, Argentina

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.

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.

Pathogenic and enzyme activities of the entomopathogenic fungus Tolypocladium cylindrosporum (Ascomycota: Hypocreales) from Tierra del Fuego, Argentina.

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 (4 degreeC, 12 degreeC and 24 degreeC), 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 (4 degree C, 12 degree C and 24 degree C). 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 degreeC), 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 degreeC or 12 degreeC. 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.

α-L-rhamnosidase and ß-D-glucosidase activities in fungal strains isolated from alkaline soils and their potential in naringin hydrolysis.

α-L-Rhamnosidases (EC 3.2.1.40) and ß-D-glucosidases (EC 3.2.1.21) obtained from several microbial sources are potential catalysts in food, beverage, and pharmaceutical industries. However, the enzyme preparations currently used have limitations related to the stability and activity of the enzyme as well to their reuse. A microtiter screening was carried out in 55 fungal strains isolated from alkaline soils, to obtain active α-L-rhamnosidases and ß-D-glucosidases at pH 9.0. While α-L-rhamnosidase activity was detected in 45% of the strains tested, ß-D-glucosidase activity was found only in 27%. Based on the fungal ability to produce α -L-rhamnosidase activity, cultures were supplemented with naringin to study the activities of the enzymes and the potential of the fungal strains on naringin hydrolysis. About 70% of the fungal strains tested increased the activities of both enzymes in the naringin-supplemented cultures as compared to non-supplemented ones. This effect was higher in Acrostalagmus luteo-albus LPSC 427 (15.3 fold) for α-L-rhamnosidase activity and Metarrhizium anisopliae LPSC 996 (51.1 fold) for ß-D-glucosidase activity. All the enzyme preparations tested hydrolyzed naringin at pH 9.0, being that obtained from Acremonium murorun LPSC 927 cultures the one which showed highest hydrolysis. Here, different fungal species are reported for the first time for their ability to produce α-L-rhamnosidase and ß-D-glucosidase activity at alkaline pH.

Microbióta alcalofílica y alcalinotolerante en suelos de bosques xéricos en una localidad de la provincia de Buenos Aires, Argentina / Alkalophilic and alkali-tolerant mycobiota in xeric forest soils from a locality of the Province of Buenos Aires, Argentina

Se estudió la micobiota alcalofílica y alcalino tolerante de suelos de intercordones del bosque nativo de Celtis tala y Scutia buxifolia en el Partido de Magdalena, provincia de Buenos Aires, Argentina. Los aislamientos de los geohongos se realizaron en agar extractos de malta en rangos de pH desde 5 hasta 11, ajustados mediante diferentes concentraciones de sales sódicas. Se aislaron e identificaron 43 taxa fúngicos. El 50 por ciento no fueron capaces de crecer a pH 10 siendo asignados a la categoría de alcalófilos. El 39 por ciento fueron alcalino-tolerantes dado que pudieron ser aislados hasta pH 10, mientras que el 11 por ciento restante creció a pH 10 pero no a pH 5-6 y fueron asignados a la categoría de alcalofílicos. Sólo Fusarium solari fue aislado con altas frecuencias en suelos de los 3 intercordones en todos lo pH probados.

A. robusta sp. nov., a new species of Achlya (Saprolegniales, Straminipila) from a polluted Argentine channel.

Achlya robusta sp. nov. was found on litter (floating twigs, leaves, and roots) in an artificial polluted channel, near a petroleum refinery, in Buenos Aires province, Argentina. The species is described, illustrated and compared with other species of the genus. A. robusta produces mainly smooth and papillate, tuberculate or bullate oogonia and monoclinous antheridial branches. It develops spherical and subglobose oogonia, with the oogonial wall yellowish and containing mainly immature oospheres. The oospores are eccentric and ranging from (1) 4-17 (30) per oogonium.