Effect of essential oils on the development of Colletotrichum sp. fungus in fragments of Feijoa sellowiana fruits

The aim of this work was to evaluate the effect of the essential oils of Syzygium aromaticum, Cymbopogon citratus, Eucalyptus citriodora and Rosmarinus officinalis on the mycelial development of the fungus Colletotrichum sp. in fragments of Feijoa sellowiana fruits. The essential oils were incorporated in the PDA (Potato-Dextrose-Agar) medium in the concentrations of 250, 500 and 1000 ppm, 0 ppm (PDA only) (negative control), and fungicide fluazinam 1% (positive control). The area under the mycelial growth curve (AUMGC) and percent inhibition of mycelial growth (PIMG) were calculated. In the second evaluation, fruits fragments bordering the disease symptom were immersed in essential oils aqueous solution of S. aromaticum, C. citratus, and E. citriodora, at the concentration of 5000 ppm, 0 ppm (water only - negative control) and fluazinam 1% (positive control). The immersion times in the treatments were: 2, 4, 8, 12 and 24 hours, with subsequent incubation in Agar-Agar medium at 25°C. This evaluation was performed daily for 15 days, observing the moment of fungal germination through the emission of the mycelium. It was verified from the obtained results that all treatments reduced the fungal growth, and the essential oils of C. citratus and S. aromaticum totally inhibited its growth from the dose 500 and 1000 ppm, respectively. Regarding the test on fruit fragments, the essential oil of S. aromaticum at the immersion times of 12 and 24 hours was effective in inhibiting the fungus until the 15th day of evaluation.

The improvement of bioactive secondary metabolites accumulation in Rumex gmelini Turcz through co-culture with endophytic fungi

Abstract Aspergillus sp., Fusarium sp., and Ramularia sp. were endophytic fungi isolated from Rumex gmelini Turcz (RGT), all of these three strains could produce some similar bioactive secondary metabolites of their host. However the ability to produce active components degraded significantly after cultured these fungi alone for a long time, and were difficult to recover. In order to obtain more bioactive secondary metabolites, the co-culture of tissue culture seedlings of RGT and its endophytic fungi were established respectively, and RGT seedling was selected as producer. Among these fungi, Aspergillus sp. showed the most significant enhancement on bioactive components accumulation in RGT seedlings. When inoculated Aspergillus sp. spores into media of RGT seedlings that had taken root for 20 d, and made spore concentration in co-culture medium was 1 × 104 mL-1, after co-cultured for 12 d, the yield of chrysophaein, resveratrol, chrysophanol, emodin and physcion were 3.52-, 3.70-, 3.60-, 4.25-, 3.85-fold of the control group. The extreme value of musizin yield was 0.289 mg, which was not detected in the control groups. The results indicated that co-culture with endophytic fungi could significantly enhance bioactive secondary metabolites production of RGT seedlings.

Primer registro de Talaromyces udagawae relacionado con cuerpos humanos en descomposición, en suelo de la Argentina / First record of Talaromyces udagawae in soil related to decomposing human remains in Argentina

The morphologic features of Talaromyces udagawae Stolk and Samson are here described and illustrated. This teleomorphic Ascomycota fungus was isolated from soil obtained in Buenos Aires province (Argentina) from beneath a human cadaver in an advanced state of decomposition. After washing and serial dilution of the soil along with moist-chamber techniques for fungal cultivation, T. udagawae formed very restricted colonies of bright yellow color on different growth media with 8-ascospored asci. The ascospores were ellipsoidal and ornamented. The anamorphic state was not observed. Molecular-genetic techniques identified the species. The present record is the first of the species in Argentina, pointing it as a tool to identify soils where cadaver decomposition occurs.

Se describen e ilustran las características morfológicas de Talaromyces udagawae Stolk y Samson. Se aisló el estado teleomórfico de este hongo Ascomycota de suelo obtenido en la provincia de Buenos Aires (Argentina), por debajo de un cadáver humano en avanzado estado de descomposición. Las muestras de suelo fueron analizadas mediante lavado, dilución seriada y cámaras húmedas, técnicas ampliamente usadas para el estudio de hongos de suelo. T. udagawae formó colonias muy restringidas de color amarillo brillante en diferentes medios de cultivo, con ascos con 8 ascosporas. Las ascosporas eran elipsoidales y ornamentadas. No fue hallado el estado anamórfico. La especie también fue identificada mediante técnicas moleculares. El presente registro es el primero de la especie en la Argentina y el único que la postula como herramienta para identificar suelos donde ocurre una descomposición cadavérica.

Ciclo de vida de corynelia tropica, patógeno foliar en podocarpus saligna / Life cycle of corynelia tropica, leaf pathogen on podocarpus saligna

El presente estudio tuvo como objetivo determinar el ciclo de vida de Corynelia tropica, patógeno de hojas y ramillas en mañío de hoja larga (Podocarpus saligna). Mensualmente se recolectaron ramillas de P. saligna. En la medida que se fueron detectando estadíos interesantes dentro del ciclo de vida de este patógeno, la frecuencia de las colectas se intensificó en forma quincenal, e incluso semanal. Se pudo constatar que C. tropica presentó un ciclo de vida anual muy definido, con gran regularidad en la aparición y desarrollo de sus estructuras fructíferas. Invariablemente el ciclo de vida se inició en la primera quincena de noviembre con la inoculación de los nuevos brotes de P. saligna. A inicios de enero se manifestaron los primeros síntomas de la infección y a comienzos de marzo ya eran notorias las estructuras del anamorfo. A fines de mayo las estructuras del teleomorfo se hacían protuberantes y se iniciaba la formación de los ascos. A fines de julio los ascocarpos presentaban forma y tamaño ya adulto, y las ascosporas al interior de los ascos se encontraban en proceso de maduración. A fines de octubre las ascosporas ya estaban maduras y su liberación a comienzos de noviembre, sincronizaba con la emergencia de los brotes de P. saligna, con lo que se daba inicio una vez más a un nuevo ciclo de vida de C. tropica. Se pudo constatar que además del follaje y ramas, este patógeno también atacaba a los frutos de P.saligna.

This study aimed to determine the life cycle of Corynelia tropica, pathogen leaves and twins in longleaf mañío (Podocarpus saligna). Monthly P. saligna twigs were collected. As they were detecting interesting stages in the life cycle of this pathogen, the frequency of collections were intensified fortnightly or even weekly. It was found that C. tropica presented a very defined, with great regularity in the occurrence and development of their fruiting structures annual life cycle. Invariably the life cycle began in the first half of November with the inoculation of new outbreaks of P. saligna. In early January the first symptoms of infections manifested and early March were already notorious the anamorph structure. In late May teleomorph structures became prominent and the formation of the asci began. In late July the ascocarps presented adult size and shape, and the ascospores within the asci were maturing. In late October ascospores were ripe and in early November, release synchronized with outbreaks of P. saligna, which was given start again a new life cycle of C. tropica. It was found that besides the foliage and branches, this pathogen also attacked the fruits of P. saligna.

Low doses of gamma radiation in the management of postharvest Lasiodiplodia theobromae in mangos

The postharvest life of mango is limited by the development of pathogens, especially fungi that cause rot, among which stands out the Lasiodiplodia theobromae. Several control methods have been employed to minimize the damages caused by this fungus, chemical control can leave residues to man and nature; physical control by the use of gamma radiation in combination with modified atmosphere and cold storage. The use of gamma radiation helps to reduce the severity of the pathogen assist in the ripening process of fruits, even at low doses (0.25, 0.35 and 0.45 kGy) chemical properties such as pH, soluble solids, acid ascorbic, titratable acidity and also the quality parameters of the pulp showed no damage that are ideal for trade and consumption of mangoes. This treatment can be extended for use in the management of diseases such as natural infections for penducular rot complex that has as one of L. theobroma pathogens involved.

Epicoccum nigrum and Cladosporium sp. for the treatment of oily effluent in an air-lift reactor

The metalworking industry is responsible for one of the most complex and difficult to handle oily effluents. These effluents consist of cutting fluids, which provide refrigeration and purification of metallic pieces in the machining system. When these effluents are biologically treated, is important to do this with autochthonous microorganisms; the use of these microorganisms (bioaugmentation) tends to be more efficient because they are already adapted to the existing pollutants. For this purpose, this study aimed to use two indigenous microorganisms, Epicoccum nigrum and Cladosporium sp. for metalworking effluent treatment using an air-lift reactor; the fungus Aspergillus niger (laboratory strain) was used as a reference microorganism. The original effluent characterization presented considerable pollutant potential. The color of the effluent was 1495 mg Pt/L, and it contained 59 mg/L H2O2, 53 mg/L total phenols, 2.5 mgO2/L dissolved oxygen (DO), and 887 mg/L oil and grease. The COD was 9147 mgO2/L and the chronic toxicity factor was 1667. Following biotreatment, the fungus Epicoccum nigrum was found to be the most efficient in reducing (effective reduction) the majority of the parameters (26% COD, 12% H2O2, 59% total phenols, and 40% oil and grease), while Cladosporium sp. was more efficient in color reduction (77%).

Xanthophyllomyces dendrorhous (Phaffia rhodozyma) on stromata of Cyttaria hariotii in northwestern Patagonian Nothofagus forests

The occurrence and distribution of Xanthophyllomyces dendrorhous associated with Cyttaria hariotii parasitizing three Nothofagus species (N. dombeyi, N. antarctica and N. pumilio) in northwestern Patagonia (Argentina), as well as the factors that may affect this distribution were herein studied. Between 2000 and 2007, samples were obtained from 18 different locations. Based on physiological tests and morphological characteristics of sexual structures, 72 isolates were identified as X. dendrorhous. Representative strains were studied by MSP-PCR fingerprinting and sequence analysis of the ITS region. MSP-PCR fingerprints were similar for the newly isolated strains, and were also identical to the profiles of the strains previously found in this region. Patagonian strains appear to be a genetically uniform and distinct population, supporting the hypothesis that the association with different host species has determined genetically distinct X. dendrorhous populations worldwide. X. dendrorhous was recovered from N. dombeyi and N. antarctica. Approximately half the sampling sites and samples were positive for X. dendrorhous, but the isolation recovery rate was low. X. dendrorhous was absent in the early stages of ascostromata maturation, becoming more abundant in later stages. The present work represents a step forward in the understanding of the natural distribution and ecology of this biotechnologically relevant yeast.

Xanthophyllomyces dendrorhous (Phaffia rhodozyma) asociado a estromas de Cyttaria hariotii en bosques de Nothofagus en el noroeste de la Patagonia. Se estudió la ocurrencia y la distribución de Xanthophyllomyces dendrorhous asociado a Cyttaria hariotii en tres especies de Nothofagus (N. dombeyi, N. antarctica y N. pumilio) del noroeste de la Patagonia (Argentina), y los factores que podrían afectar esta distribución. El muestreo se realizó entre 2000 y 2007 en 18 sitios diferentes. Según las pruebas fisiológicas y las características morfológicas de las estructuras sexuales, 72 de los aislamientos obtenidos se identificaron como X. dendrorhous. Se estudiaron cepas representativas mediante la técnica de MSP-PCR fingerprinting y secuenciación de la región ITS. Los perfiles de MSP-PCR fueron similares, tanto entre los nuevos aislamientos como entre estos y los de cepas previamente obtenidas en la región. Aparentemente, las cepas patagónicas forman una población genéticamente uniforme y distinta de otras poblaciones. Esto apoya la hipótesis de que la asociación con diferentes especies hospedadoras ha determinado la diferenciación genética de X. dendrorhous en todo el mundo. X. dendrorhous se recuperó de N. dombeyi y de N. antarctica. Aproximadamente la mitad de los sitios de muestreo y de muestras fueron positivos para X. dendrorhous, pero la tasa de aislamiento fue muy baja. X. dendrorhous está ausente en estadios tempranos de maduración de ascostromas y se hace más abundante en estadios más tardíos. El presente trabajo contribuye al mejor entendimiento de la distribución natural y la ecología de esta levadura, de relevancia biotecnológica.

Growth of Byssochlamys nivea in pineapple juice under the effect of water activity and ascospore age

The study of thermal resistant mould, including Byssochlamys nivea, is of extreme importance since it has been associated with fruit and fruit products. The aim of this work is to analyze the influence of water activity (a w) and ascospore age (I) on the growth of Byssochlamys nivea in pineapple juice. Mold growth was carried out under different conditions of water activity (a w) (0.99, 0.96, 0.95, 0.93, 0.90) and ascospore age (I) (30, 51, 60, 69, 90 days). Growth parameters as length of adaptation phase (λ), maximum specific growth rate (µmax) and maximum diameter reached by the colony (λ) were obtained through the fit of the Modified Gompertz model to experimental data (measuring radial colony diameter). Statistica 6.0 was used for statistical analyses (significance level α = 0.05). The results obtained clearly showed that water activity is statistically significant and that it influences all growth parameters, while ascospore age does not have any statistically significant influence on growth parameters. Also, these data showed that by increasing a w from 0.90 to 0.99, the λ value substantially decreased, while µmax and λ values rose. The data contributed for the understanding of the behavior of B. nivea in pineapple juice. Therefore, it provided mathematical models that can well predict growth parameters, also helping on microbiological control and products' shelf life determination.

Isolation of Papulaspora halima and a new morphological variety of Halosphaeria tubulifera from seawater of potter cove (King George Island, South Shetland Island, Antarctica) / Aislamiento de Papulaspora halima y de una nueva variedad morfológica de Halosphaeria tubulifera desde agua de mar de Potter Cove (Isla Rey Jorge /25 de Mayo, islas Shetland del Sur, Antártida)

Marine fungi ascribed to the ascomycetes and the hyphomycetes are infrequently reported for the Southern Ocean. For this reason, the main objective of the present work was to detect the presence of these fungi seawater of Potter Cove, King George (25 de Mayo) Island, South Shetland Island, Antarctica. For this purpose marine fungi were grown on wood test panels, placed into plastic nets in the tidal zone, exposed to the Antarctic seawater for different periods of time, which ranged between 2 and 12 months.As a result of this survey, we were able to recover and identify two marine fungi, Papulospora halima (which represents the first report for this environment) and a new morphological variety of Halosphaeria tubulifera.

Los ascomicetes e hifomicetes marinos están escasamente documentados para el océano Atlántico Sur. Por este motivo, el principal objetivo del presente trabajo fue detectar la presencia de dichos hongos en las agua marinas de la Potter Cove, en la isla Rey Jorge/25 de Mayo (islas Shetland del Sur, Antártida). Para este propósito, los hongos marinos se desarrollaron en paneles de madera dentro de una red plástica en la zona tidal, expuestos al agua de mar antártica por diferentes períodos de tiempo que oscilaron entre 2 a 12 meses. Como resultado de este estudio, fuimos capaces de recuperar e identificar 2 hongos marinos, Papulospora halima (que representa el primer reporte para este ambiente) y una nueva variedad morfológica de Halosphaeria tubulifera.

Selection of endophytic fungi from comfrey (Symphytum officinale L. ) for in vitro biological control of the phytopathogen Sclerotinia sclerotiorum (Lib. ) / Seleção de fungos endofíticos de confrei (Symphytum officinale L. ), buscando controle biológico in vitro do fitopatógeno Sclerotinia sclerotiorum (Lib. )

Biological control consists of using one organism to attack another that may cause economic damage to crops. Integrated Pest Management (IPM) is a very common strategy. The white mold produced by Sclerotiniasclerotiorum (Lib.) causes considerable damage to bean crops. This fungus is a soil inhabitant, the symptoms of which are characterized by water-soaked lesions covered by a white cottony fungal growth on the soil surface and/or the host plant. Possible biological control agents taken from plants are being investigated as phytopathogen inhibitors. These are endophytic microorganisms that inhabit the intercellular spaces of vegetal tissues and are often responsible for antimicrobial production. The objective of the present study was to select endophytic fungi isolated from comfrey (Symphytumofficinale L.) leaves with in vitro antagonist potential against the phytopathogenic fungus S. sclerotiorum. Twelve isolates of endophytic fungi and a pathogenic strain of S. sclerotiorum were used in the challenge method. With the aid of this method, four endophytes with the best antagonistic activity against S. sclerotiorum were selected. Pathogen growth inhibition zones were considered indicative of antibiosis. The percentages of pathogenic mycelia growth were measured both with and without the antagonist, resulting in growth reductions of 46.7% to 50.0% for S. sclerotiorum. These analyses were performed by evaluating the endophytic/pathogenic mycelia growth in mm/day over an eight-day period of antagonistic tests.

O controle biológico consiste no uso de organismos que atacam outros que causam danos a culturas de plantas. Esta é uma estratégia muito utilizada no Controle Integrado de Pragas (CIP). O mofo branco, causado por Sclerotiniasclerotiorum (Lib.), causa danos em culturas de feijão. Este fungo é encontrado no solo e seus sintomas são caracterizados por lesões úmidas cobertas por micélios algodonosos, crescidos a partir do solo e/ou da planta hospedeira. Há relatos de pesquisas buscando agentes potenciais de controle biológico isolados de plantas para controlar fungos fitopatogênicos. Entre estes agentes encontram-se os microrganismos endofíticos, habitantes de espaços intercelulares de tecidos vegetais, muitas vezes responsáveis pela produção de substâncias antimicrobianas. Este trabalho teve por objetivo selecionar linhagens endofíticas isoladas de folhas de confrei (Symphytumofficinale L.), com potencial de antagonismo in vitro contra a linhagem fitopatogênica S. sclerotiorum. Doze linhagens de fungos endofíticos foram utilizadas na técnica de desafio em placa contra um isolado patogênico de S. sclerotiorum. Com o auxílio desta técnica, quatro linhagens com melhor atividade antagonística contra S. sclerotiorum foram selecionadas. Zonas de inibição no crescimento da linhagem patogênica foram consideradas como indicativo de antibiose. Foram efetuadas análises da porcentagem de elongação micelial com e sem antagonismo, mostrando resultados de 46,7% a 50,0% de redução no crescimento micelial do fitopatógeno. Estas análises consistiram de avaliações das medidas do crescimento em mm/dia das linhagens endofíticas/patogênica em testes de antagonismo.

Influence of culture media and environmental factors on mycelial growth and sporulation of Lasiodiplodia theobromae (Pat.) Griffon and Maubl.

Lasiodiplodia theobromae, a common tea (Camellia sinensis) pathogen, usually does not sporulate or sporulates poorly in common media, which makes spore production difficult. In this study the effects of culture media, carbon source, nitrogen source, temperature, pH and light on mycelial growth and sporulation were evaluated. Among several carbon sources tested, glucose and sucrose were found superior for growth. Potassium nitrate supplemented media showed maximum growth amongst the tested inorganic nitrogen sources while peptone produced maximum growth among the tested organic nitrogen sources. Tea root extract supplemented potato dextrose agar medium was found to be the most suitable for mycelial growth and sporulation of L. theobromae. The fungus grow at temperatures ranging from 40 to 36 degrees C, with optimum growth at 28 degrees C and no growth was noted at 40 degrees C. There was no significant effect of different light period on growth of L. theobromae, but light enhanced sporulation. The fungus grow at pH 3.0-8.0 and optimum growth was observed at pH 6.0. Tea root extract supplemented potato dextrose agar medium with pH 6.0 was the most suitable for production of conidia of L. theobromae at 28 degrees C. Hence this media may be recommended for inoculum production for further studies.

Inhibition of the growth of Ascosphaera apis by Bacillus and Paenibacillus strains isolated from honey / Inhibición del crecimiento de Ascosphaera apis mediante cepas de Bacillus y Paenibacillus aisladas de miel

The fungus Ascosphaera apis, the causative agent of chalkbrood disease in honeybee larvae, occurs throughout the world and is found in many beekeeping areas of Argentina. The potential as biocontrol agents of 249 aerobic spore-forming bacterial antagonists isolated from honey samples was evaluated. Each isolate was screened against A. apis by a central disk test assay. Ten bacterial strains that showed the best antagonistic effect to A. apis were selected for further study and identified as Bacillus cereus (m363, mv86, mv81, mv75), Bacillus circulans (Fr231, m448b), Bacillus megaterium (m435), Bacillus pumilus (m354), Bacillus subtilis (m329), and Paenibacillus alvei (m321). For testing the efficiency of the selected strains, a paired culture test was used with 5 replicates of each combination bacterial antagonist / A. apis strain, and 5 replications for each control on 4 different culture media. The analysis of variance and posterior comparison of means according to LSD method showed that the best antagonists when using YGPSA medium were B. subtilis (m329) and B. megaterium (m435), and in the case of MYPGP medium the most efficient were B. circulans strains Fr 231 and m448b.

La cría yesificada es una micosis invasiva ocasionada por el hongo heterotálico Ascosphaera apis que afecta exclusivamente a las larvas de las abejas. La enfermedad tiene difusión mundial y en la Argentina se halla diseminada en todas las áreas donde se realiza apicultura. Se estudió la potencialidad de 249 cepas de bacterias esporuladas aeróbicas aisladas de miel como agentes biocontroladores del hongo mediante un ensayo en disco central en condiciones de laboratorio. Se seleccionaron como mejores antagonistas 10 cepas bacterianas identificadas como Bacillus cereus (m363, mv86, mv81, mv75), Bacillus circulans (Fr231, m448b), Bacillus megaterium (m435), Bacillus pumilus (m354), Bacillus subtilis (m329), y Paenibacillus alvei (m321). Para probar la eficiencia de las cepas seleccionadas, se empleó la técnica de cultivo dual con 5 repeticiones de cada combinación antagonista bacteriano / cepa de A. apis, 5 para cada control y 4 medios de cultivo diferentes empleando 10 cepas del hongo de distintos orígenes geográficos. El análisis de la variancia y posterior comparación de medias LSD (Least Square Dfferences) mostró que los mejores antagonistas fueron B. subtilis (m329) y B. megaterium (m435) para el caso del medio YGPSA, mientras que para MYPGP las más eficientes fueron las cepas de B. circulans Fr 231 y m448b.

Influence of fowl uropygial gland and its secretory lipid components on the growth of skin surface fungi of fowl.

Fungal species, which were shown to colonize consistently on the skin surface of the breast region of adult (1 year old) white leghorn fowl, were identified as Aspergillus sydowii, A. tamarii, A. rugulosus and Absidia corymbifera. Of these, A. sydowii and A. tamarii were the dominant forms. Two species of fungi, namely, Aspergillus niger and Scopulariopsis brevicaulis were shown to be present in the cultures of the scrubbings from breast skin surface after 60 days of captivity of the fowls. Extirpation of the uropygial gland resulted in encouragement of the in vitro population growth of all species of fungi except that of A. rugulosus. The effect was found to be very conspicuous for A. sydowii and A. tamarii, particularly after 60 days of gland removal. Addition of total lipids and the wax diester component of free-flowing uropygial secretion as 0.2% suspension in Sabouraud's agar medium of individual fungal isolates caused marked suppression of the population growth of A. sydowii, A. tamarii, Absidia corymbifera and to some extent of S. brevicaulis. Other components of secretory lipids, such as wax alcohols (2,3-alkane-diols), wax acids, triglycerides and hydrocarbons (including squalene) when supplemented separately to culture medium of individual fungi at identical concentration, were also shown to cause inhibition of the growth of most of fungal species at different degrees.

Auxotrophic requirement for sporangiospore--yeast transformation of Dimorphomyces diastaticus strain C 12.

The filamentous microorganism tentatively known as Dimorphomyces diastaticus originally isolated from fermenting soursop extract, in contradistinction grew in the considiogeneous form in glucose-ammonium sulphate-basal salts buffered medium which induced polar budding yeast cells of another dimorphic microorganism, D. pleomorphis (1). Further experiments using this medium showed that a number of growth factors including inositol, thymine and uracil separately incorporated inducted yeast morphology. Carbon substrates gave rise to polar budding yeast cells in the following order: galactose, malic acid, maltose, but mycelial fragments were preponderant in the reverse order. There was no growth with citric acid as substrate. With maltose-substrate and uracil incorporation in buffered basal salts medium, only polar budding yeast cells were induced, while granular particles abound with thymine supplementation. It was concluded that D. diastaticus strain C12 auxotrophically required a dissacharide, maltose, and pyrimidine base, uracil, for sporangiospore-yeast transformation in buffered ammonium sulphate-basal salts medium, pH 3.5.

Drechslera cactivora, nuevo agente de micosis oportunista de las uñas / Drechslera cactivora, new agent opportunistic mycosis of the nails

Hemos estudiado tres casos de onicomicosis de "hallux" producidos por Drechslera cactivora. Se describen sus caracteres micológicos, sus propiedades fisiológicas y sensibilidad a algunos agentes antifúngicos