Rev. biol. mar. oceanogr. 49(2): 293-305

Article

Variation of sterols and fatty acids as an adaptive response to changes in temperature, salinity and pH of a marine fungus Epicoccum nigrum isolated from the Patagonian Fjords

Ramón Ahumada-Rudolph^1,4,5, Daniel Cajas-Madriaga¹, Anny Rudolph², Rodrigo Reinoso¹, Cristian Torres³, Mario Silva¹ and José Becerra¹

¹Laboratorio de Química de Productos Naturales, Departamento Botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepción, Casilla 160-C, Chile

²Facultad de Ciencias, Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepción, Chile

³Laboratorio de Genómica & Biodiversidad (LGB), Departamento de Ciencias Naturales, Universidad del Bío-Bío, Dieciocho de Septiembre 580, Chillán, Chile

⁴EULA-Chile Environmental Sciences Centre, Universidad de Concepción, Chile

⁵Programa de Postgrados en Oceanografía, Departamento de Oceanografía, Universidad de Concepción, Casilla 160-C, Chile

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We isolated and identified a marine fungus strain from samples of sediments obtained from a sector of the Patagonian fjords. The LQRA39-P strain was identified as Epicoccum nigrum using microscopy techniques and corroborated using molecular techniques. We expect to prove that metabolic variation responses allow ubiquitous fungi to develop in marine, freshwater, and terrestrial environments. We analyzed variations in the content of fatty acids and sterols, in a battery of culture media at different temperatures, salinity and pH. The content of fatty acids and sterols was analysed using gas chromatography coupled to mass chromatography (GC-MS). Changes in temperature showed no significant changes in the fatty acid content; nevertheless, sterol content was significantly affected by this factor at just pH 4, increasing diversity of sterols in freshwater at 25°C. Salinity generated changes in the lipid composition (i.e., C16:0; C16:1; C18:2 and C18:3). As for pH, this factor has a significant effect on the composition of fatty acids and sterols. We demonstrate that E. nigrum is capable of changing its composition of sterols and fatty acids as an adaptive response that may enable co-inhabiting marine and terrestrial substrates.

Key words:  Fungal ecology, extremophile fungus, marine fungus, secondary metabolites