Bioprospecting for novel oxylipins in fungi: The presence of 3-hydroxy oxylipins in Pilobolus

As previously found in various members of the Mucorales, 3-hydroxy oxylipin s in Mucor genevensis are associated with the sporangia, i.e. mainly the co lumella structure and between aggregating sporangiospores. To determine if this phenomenon is also true in distantly related members, the mucoralean f ungus Pilobolus was examined. This fungus is characterized by relatively la rge sub sporangial-columella structures which actively eject sporangia in a sticky liquid for attachment onto herbage surrounding its growth medium - in this case horse dung. Strikingly, this fungus produced a novel oxylipin i.e. a 3-hydroxy monounsaturated fatty acid, possibly a nonenoic acid, whic h is mainly associated with the sub sporangial-columella structure and aggr egating sporangiospores. The specificity of the antibody against 3-hydroxy oxylipins used in immunofluorescence mapping of the mucoralean fungi, was f urther confirmed in the yeast, Saccharomycopsis malanga which produces 3-hy droxy palmitate in crystal form. These crystals occur between aggregating y east cells. On the basis of the available data, we hypothesize that 3-hydro xy oxylipins probably function as adhesives, attaching fungal cells to each other or to other surfaces through entropic based hydrophobic forces and/o r hydrogen bonds.