Suchergebnisse

15 páginas, 5 figuras. ; Several studies report temporal, geographical, and intra-individual variation in sponge metabolite yields. However, the internal and/or external factors that regulate the metabolite production remain poorly understood. Dysidea avara is a demosponge that produces sesquiterpenoids (avarol and derivatives) with interesting medical properties, which has prompted addressed studies to obtain enough amounts of these metabolites for research on drug discovery. Within this framework, specimens of Dysidea avara from a population of the Northwest Mediterranean were sampled and their secondary metabolites quantified to assess their variability and the possible relationship with external (seasonality, interactions with neighbors) and internal (reproductive stages) factors. The results show a variation of the amount of both avarol and its monoacetate derivative with time, with no clear relationship with seawater temperature. A trade-off with sponge reproduction was not found either. However, our results showed for the first time that sponges are able to increase production or accumulation of secondary metabolites in their peripheral zone depending on the nature of their neighbors. This finding could explain part of the high variability in the amount of secondary metabolites usually found in chemical ecology studies on sponges and opens new biotechnological approaches to enhance the metabolite yield in sponge cultures. ; Financial support was provided by the projects BENTHOMICS (CTM2010-22218-C02) from the Ministerio de Economía y Competitividad of the Spanish Government (MICINN) and SGR2009-655 from the Generalitat de Catalunya. ; Peer reviewed

A Phoma sp. was isolated and characterized as endophytic and as a pathogen of Larrea tridentata (creosote bush) growing in the desert region of southern Utah, USA. This fungus produces a unique mixture of volatile organic compounds (VOCs), including a series of sesquiterpenoids, some alcohols and several reduced naphthalene derivatives. Trans-caryophyllene, a product in the fungal VOCs, was also noted in the VOCs of this pungent plant. The gases of Phoma sp. possess antifungal properties and is markedly similar to that of a methanolic extract of the host plant. Some of the test organisms with the greatest sensitivity to the Phoma sp. VOCs were Verticillium, Ceratocystis, Cercospora and Sclerotinia while those being the least sensitive were Trichoderma, Colletotrichum and Aspergillus. We discuss the possible involvement of VOC production by the fungus and its role in the biology/ecology of the fungus/plant/environmental relationship with implications for utilization as an energy source. ; S.K.S. is grateful to the Department of Biotechnology (DBT), the Government of India, New Delhi, for the award of an DBT Overseas Associateship in the Niche Area of Biotechnology (No. BT/IN/BTOA/NICHE/2006 dated 13 February 2008) to study at MSU, USA, and to the Department of Science and Technology (DST), New Delhi, for providing financial support to set up the National Facility for Culture Collection of Fungi (No. SP/SO/PS-55/2005) at MACS' Agharkar Research Institute, Pune, India, and to the Director, MACS' ARI, for granting permission to work at MSU. G.A.S. is grateful to the NSF and DoE for providing research funds. The BOYSCAST program of India granted a 1-year fellowship to S.Y.U.H. to study and work at MSU. We are grateful to Mr Darwin Whitaker who generously supplied plant materials from the Utah desert region on various occasions.