title: Mycosporines from freshwater yeasts: a trophic cul-de-sac?
abstract: Mycosporine-like amino-acids (MAAs) are found in aquatic bacteria, algae, and animals. A related compound, the mycosporine-glutaminol-glucoside (myc-glu-glu), has recently been reported in freshwater yeasts. Although animals depend on other organisms as their source of MAAs, they can efficiently accumulate them in their tissues. In this work we assessed the potential transfer of the yeast mycosporine myc-glu-glu from the diet into the copepod Boeckella antiqua and the ciliate Paramecium bursaria. For this purpose, we performed experiments to study the feeding of B. antiqua and P. bursaria on the yeast Rhodotorula minuta and their ability to bioaccumulate myc-glu-glu. Bioaccumulation of myc-glu-glu in B. antiqua was assessed through long-term factorial experiments manipulating the diet (Chlamydomonas reinhardii and C. reinhardii + yeasts) and radiation exposure (PAR and PAR + UVR). Shorter term experiments were designed in the case of P. bursaria. The composition and concentration of MAAs in the diet and in the consumers were determined by HPLC analyses. Our results showed that even though both consumers ingested yeast cells, they were unable to accumulate myc-glu-glu. Moreover, when exposed to conditions that stimulated the accumulation of photoprotective compounds (i.e. UVR exposure), an increase in MAAs concentration occurred in copepods fed C. reinhardii plus yeasts as well as in those fed only C. reinhardii. This suggests that the copepods were able to modify their tissue concentrations of MAAs in response to environmental clues but also that the contribution of yeast mycosporines to total MAAs concentration was negligible.
authors.affiliation: Laboratorio de Fotobiología, Centro Regional Universitario Bariloche, Universidad Nacional del Comahue, U. P. Universidad, 8400 Bariloche, Argentina. perezp@arnet.com.ar
authors.forename: Patricia
authors.initials: P
authors.lastname: Pérez
authors.forename: Diego
authors.initials: D
authors.lastname: Libkind
authors.forename: María Del Carmen
authors.initials: Mdel C
authors.lastname: Diéguez
authors.forename: Monika
authors.initials: M
authors.lastname: Summerer
authors.forename: Bettina
authors.initials: B
authors.lastname: Sonntag
authors.forename: Ruben
authors.initials: R
authors.lastname: Sommaruga
authors.forename: María
authors.initials: M
authors.lastname: van Broock
authors.forename: Horacio E
authors.initials: HE
authors.lastname: Zagarese
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D033342:Copepoda / Q000378:metabolism / Q000382:microbiology / Q000528:radiation effects; D003511:Cyclohexanols / Q000378:metabolism* / Q000528:radiation effects; D005618:Fresh Water / Q000382:microbiology; D005960:Glucosides / Q000378:metabolism* / Q000528:radiation effects; D010247:Paramecium / Q000378:metabolism / Q000382:microbiology / Q000528:radiation effects; D012248:Rhodotorula / Q000737:chemistry* / Q000378:metabolism* / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D003511:Cyclohexanols; D005960:Glucosides; C474430:mycosporine-glutamicol-glucoside