RESUMO

In dual culture confrontation assays, basidiomycete Irpex lacteus efficiently antagonized Fusarium spp., Colletotrichum spp., and Phytophthora spp. phytopathogenic strains, with growth inhibition percentages between 16.7-46.3%. Antibiosis assays evaluating the inhibitory effect of soluble extracellular metabolites indicated I. lacteus strain inhibited phytopathogens growth between 32.0-86.7%. Metabolites in the extracellular broth filtrate, identified by UPLC-QTOF mass spectrometer, included nine terpenes, two aldehydes, and derivatives of a polyketide, a quinazoline, and a xanthone, several of which had antifungal activity. I. lacteus strain and its extracellular metabolites might be valuable tools for phytopathogenic fungi and oomycete biocontrol of agricultural relevance.

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Pythium insidiosum é um oomiceto aquático e agente etiológico da pitiose, uma doença de prognóstico desfavorável que acomete mamíferos. Apesar dos avanços nas pesquisas em protocolos terapêuticos, a pitiose continua sendo uma enfermidade de difícil tratamento. Neste trabalho verificou-se a atividade antimicrobiana in vitro do óleo de girassol ozonizado (OGO) frente a P.insidiosum, bem como foi avaliada a inibição do crescimento do oomiceto a partir de kunkers submetidos ao tratamento com OGO. O inóculo utilizado no teste de suscetibilidade in vitro foi preparado a partir de cultura micelial de P.insidiosum (n=30) e os ensaios foram realizados de acordo com o protocolo M38-A2 (CLSI). O OGO foi obtido comercialmente e as concentrações testadas variaram de 56.000 119/mL a 0,05119/mL. A leitura foi realizada em 48h de incubação e a presença ou ausência de hifas foi levada em consideração. Os resultados dos testes de suscetibilidade demonstraram que a CIM50 e CIM90 foram de 3500 119/mL e 28000 119/mL, respectivamente. Nos ensaios de inibição do crescimento de P. insidiosum a partir de kunkers observou-se que o OGO inibiu completamente o crescimento do oomiceto. Os resultados obtidos permitem inferir que o OGO apresenta relevante atividade anti-P. insidiosum podendo ser um potente aliado nos protocolos terapêuticos da pitiose.(AU)

Pythium insidiosum is an aquatic oomycete and etiologic agent of pythiosis. This disease has an unfavorable prognosis and affecting mammals. Despite advances in treatment, pythiosis remains a difficult disease to treat. In this work, the in vitro ozonated sunflower seed oil (OGO) antimicrobial activity was verified against P.insidiosum isolates. Additionally, we evaluated the oomycete growth inhibition from kunkers submitted to OGO treatment. The inoculum was prepared from P. insidiosum mycelial culture (n=30) and susceptibility tests were performed according to CLSIM38-A2 protocol. OGO was obtained commercially and the concentrations tested ranged from 56,000 119/mL to 0.05119/mL. The reading of results was done at 48h of incubation, and the visual presence or absence of hyphae was taken into consideration. The susceptibility test results showed that the MIC50 and MIC90were 3,500 119/mL and 28,000 119/mL, respectively. In the growth inhibition assays from kunkers it was observed that OGO completely inhibited the oomycete growth. The results allow us to infer that OGO has relevant anti-P. insidiosum activity and may be a potent assistant in the therapeutic protocols of pythiosis.(AU)

Pythium insidiosum es un oomiceto acuático y agente etiológico de la pitiosis, una enfermedad con un pronóstico desfavorable que afecta a los mamíferos. Apesar de los avances en la investigación en tratamientos, la pitiosis sigue una enfermedad difícil de tratar. En este trabajo, se verificó la actividad antimicrobiana in vitro del aceite de girasol ozonizado (OGO) contra P.insidiosum, y se evaluó la inhibición del crecimiento del oomiceto en kunkers sometidos al tratamiento con OGO. El inóculo utilizado en la prueba de susceptibilidad se preparó a partir del cultivo micelial de P.insidiosum (n=30) y los ensayos se realizaron de acuerdo con el protocolo M38-A2 (CLSI). El OGO se obtuvo comercialmente y las concentraciones variaron de 56.000 119/mL a 0,05119/mL. La lectura se realizó a las 48h de incubación y se tuvo en cuenta la presencia o ausencia de hifas. Los resultados de los ensayos de susceptibilidad mostraron que CIM50 y CIM90 fueron 3.500 119/mL y 28.000 119/mL, respectivamente. En los ensayos de inhibición del crecimiento de P. insidiosum de los kunkers se observó que OGO inhibía completamente el crecimiento del oomiceto. Los resultados nos permiten inferir que OGO tiene una relevante actividad anti-P. insidiosum y puede ser un poderoso aliado de los protocolos terapéuticos en la pitiosis.(AU)

Assuntos

RESUMO

Pythium insidiosum é um oomiceto aquático e agente etiológico da pitiose, uma doença de prognóstico desfavorável que acomete mamíferos. Apesar dos avanços nas pesquisas em protocolos terapêuticos, a pitiose continua sendo uma enfermidade de difícil tratamento. Neste trabalho verificou-se a atividade antimicrobiana in vitro do óleo de girassol ozonizado (OGO) frente a P.insidiosum, bem como foi avaliada a inibição do crescimento do oomiceto a partir de kunkers submetidos ao tratamento com OGO. O inóculo utilizado no teste de suscetibilidade in vitro foi preparado a partir de cultura micelial de P.insidiosum (n=30) e os ensaios foram realizados de acordo com o protocolo M38-A2 (CLSI). O OGO foi obtido comercialmente e as concentrações testadas variaram de 56.000 119/mL a 0,05119/mL. A leitura foi realizada em 48h de incubação e a presença ou ausência de hifas foi levada em consideração. Os resultados dos testes de suscetibilidade demonstraram que a CIM50 e CIM90 foram de 3500 119/mL e 28000 119/mL, respectivamente. Nos ensaios de inibição do crescimento de P. insidiosum a partir de kunkers observou-se que o OGO inibiu completamente o crescimento do oomiceto. Os resultados obtidos permitem inferir que o OGO apresenta relevante atividade anti-P. insidiosum podendo ser um potente aliado nos protocolos terapêuticos da pitiose.

Pythium insidiosum is an aquatic oomycete and etiologic agent of pythiosis. This disease has an unfavorable prognosis and affecting mammals. Despite advances in treatment, pythiosis remains a difficult disease to treat. In this work, the in vitro ozonated sunflower seed oil (OGO) antimicrobial activity was verified against P.insidiosum isolates. Additionally, we evaluated the oomycete growth inhibition from kunkers submitted to OGO treatment. The inoculum was prepared from P. insidiosum mycelial culture (n=30) and susceptibility tests were performed according to CLSIM38-A2 protocol. OGO was obtained commercially and the concentrations tested ranged from 56,000 119/mL to 0.05119/mL. The reading of results was done at 48h of incubation, and the visual presence or absence of hyphae was taken into consideration. The susceptibility test results showed that the MIC50 and MIC90were 3,500 119/mL and 28,000 119/mL, respectively. In the growth inhibition assays from kunkers it was observed that OGO completely inhibited the oomycete growth. The results allow us to infer that OGO has relevant anti-P. insidiosum activity and may be a potent assistant in the therapeutic protocols of pythiosis.

Pythium insidiosum es un oomiceto acuático y agente etiológico de la pitiosis, una enfermedad con un pronóstico desfavorable que afecta a los mamíferos. Apesar de los avances en la investigación en tratamientos, la pitiosis sigue una enfermedad difícil de tratar. En este trabajo, se verificó la actividad antimicrobiana in vitro del aceite de girasol ozonizado (OGO) contra P.insidiosum, y se evaluó la inhibición del crecimiento del oomiceto en kunkers sometidos al tratamiento con OGO. El inóculo utilizado en la prueba de susceptibilidad se preparó a partir del cultivo micelial de P.insidiosum (n=30) y los ensayos se realizaron de acuerdo con el protocolo M38-A2 (CLSI). El OGO se obtuvo comercialmente y las concentraciones variaron de 56.000 119/mL a 0,05119/mL. La lectura se realizó a las 48h de incubación y se tuvo en cuenta la presencia o ausencia de hifas. Los resultados de los ensayos de susceptibilidad mostraron que CIM50 y CIM90 fueron 3.500 119/mL y 28.000 119/mL, respectivamente. En los ensayos de inhibición del crecimiento de P. insidiosum de los kunkers se observó que OGO inhibía completamente el crecimiento del oomiceto. Los resultados nos permiten inferir que OGO tiene una relevante actividad anti-P. insidiosum y puede ser un poderoso aliado de los protocolos terapéuticos en la pitiosis.

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A series of novel dihydrochalcone derivatives 2-7 were synthesized from dihydroisorcordoin 1 which was isolated from the aerial parts of Adesmia balsamica. The structures of all compounds were confirmed by 1H NMR, 13C NMR, and HRMS. Their anti-oomycete activity was evaluated in vitro against Saprolegnia parasitica and Saprolegnia diclina. Some of the newly synthesized compounds exhibited better anti-oomycete activities at low values compared with bronopol and fluconazole as positive controls. Among them, compound 7 exhibited strong activity, with minimum inhibitory concentration and minimum oomyceticidal concentration values of 75 and 100 µg/mL, respectively.

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AIMS: To determine the antifungal, anti-oomycete and phytotoxic activity; and chemical composition of the volatile organic compounds (VOCs) produced by endophytic fungus Xylaria sp. PB3f3 isolated from Haematoxylon brasiletto Karst. METHODS AND RESULTS: Bioactivity and chemical composition of the VOCs from Xylaria sp. PB3f3 were established by using simple and multiple antagonism bioassays, and gas chromatography/mass spectrometry, respectively. The results showed that Xylaria sp. PB3f3 inhibited the growth of the oomycetes Pythium aphanidermatum (78·3%), Phytophthora capsici (48·3%), and the fungi Alternaria solani (24·5%) and Fusarium oxysporum (24·2%), in multiple antagonism bioassays. Volatile organic compounds, produced at 20 and 30 days of fungal growth, inhibited root elongation on Amaranthus hypochondriacus (27·6%) and on Solanum lycopersicum (53·2%). Forty VOCs were identified at 10, 20 and 30 days in Xylaria sp. PB3f3 cultures. The compounds with the highest fibre affinity were: 3-methyl-1-butanol and thujopsene, at 10 days of fungal growth; an unidentified amine and 2-methyl-1-butanol at 20 days; and 2-methyl-1-propanol at 30 days. In the gas phase assay method 2-methyl-1-propanol and 2-methyl-1-butanol showed significant inhibitory effects on root elongation and germination of Am. hypochondriacus and S. lycopersicum. CONCLUSIONS: Xylaria sp. PB3f3 and its VOCs showed significant phytotoxic effects on root elongation and germination of Am. hypochondriacus and S. lycopersicum. SIGNIFICANCE AND IMPACT OF THE STUDY: The genus Xylaria produces a great variety of secondary metabolites, but, up date, there are no reports of the identification of bioactive volatile compounds. Thus, Xylaria sp. PB3f3 and its VOCs are a possible candidate for the biological control of weeds.

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Laureliopsis philippiana (Looser) R. Schodde (Monimiaceae) is a native tree widespread in the forest areas in the south of Chile and Argentina, known for its medicinal properties and excellent wood. The aim of this study was to evaluate the chemical composition of L. philippiana leaf and bark essential oils (EOs) using gas chromatography-mass spectrometry (GC-MS), and to quantify its anti-oomycete activity, specifically against Saprolegnia parasitica and S. australis. Only six components were identified in leaf EO, 96.92% of which are phenylpropanoids and 3.08% are terpenes. As for bark EO, 29 components were identified, representing 67.61% for phenylpropanoids and 32.39% for terpenes. Leaf EO was characterized mainly by safrole (96.92%) and ß-phellandrene (1.80%). Bark EO was characterized mainly by isosafrole (30.07%), safrole (24.41%), eucalyptol (13.89%), methyleugenol (7.12%), and eugenol (6.01%). Bark EO has the most promising anti-Saprolegnia activity, with a minimum inhibition concentration (MIC) value of 30.0 µg/mL against mycelia growth and a minimum fungicidal concentration (MFC) value of 50.0 µg/mL against spores; for leaf EO, the MIC and MFC values are 100 and 125 µg/mL, respectively. These findings demonstrate that bark EO has potential to be developed as a remedy for the control of Saprolegnia spp. in aquaculture.

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In this work, we examined the production of infective zoospores of Lagenidium giganteum in four culture media, and the larvicidal activity of the cultures was determined against Aedes aegypti larvae, as well as the effect of polymer encapsulation. Medium containing sunflower seed extract showed the greatest production of zoospores, 5.92×10(6) zoospores/ml after six days of fermentation at 25±2°C and 150rpm shaking. This culture tested against A. aegypti 1st stage larvae caused different mortality rates at 24, 48 and 72h posttreatment. The LC(50) obtained was 43.9, 41.1 and 42.9µl of total culture/ml, at 24, 48 and 72h posttreatment respectively, while the culture grown in medium with soybean meal showed 3-5 times higher LC(50) values. Finally, the total culture including mycelium, zoospores and presporangia formulated with 2.5% pectin showed significantly higher mortality rates, around 100% more than the unformulated culture, whose values were from 40 to 1% at 3, 6, 9, and 12d posttreatment in the bioassays carried out in the laboratory to determine residual activity.

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Bacteria collected in mosquito breeding ponds were evaluated for resistance to streptomycin, chloramphenicol, penicillin and trimethoprim. Mycelial growth of Lagenidium giganteum isolates from Australia, United States and Colombia were evaluated in PYG media containing one antibiotic or a mixture of these compounds. Media containing chloramphenicol reduced mycelial growth of most of the isolates. The antibiotic mixtures and penicillin-streptomycin penicillin-trimethoprim did not significantly affect mycelial growth of the isolates; however, the later substantially reduced bacterial contamination.

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