Related Experiment Video
Updated: Jul 11, 2026

A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Sulfated Oligosaccharides Mediate the Interaction between a Marine Red Alga and Its Green Algal Pathogenic Endophyte
1Station Biologique, Centre National de la Recherche Scientifique, Unité Mixte de Recherche CNRS/Laboratoires Goëmar S.A. (UMR 1931), BP 74, F-29682 Roscoff Cedex, France.
Abstract:
The endophytic green alga Acrochaete operculata completely colonizes the sporophytes of the red alga Chondrus crispus; however, it does not penetrate beyond the outer cell layers of the gametophytes. Given that the life cycle phases of C. crispus differ in the sulfation pattern of their extracellular matrix carrageenans, we investigated whether carra-geenan fragments could modulate parasite virulence. lambda-Carrageenan oligosaccharides induced release of H(2)O(2), stimulated protein synthesis, increased carrageenolytic activity, and induced specific polypeptides in the pathogen, resulting in a marked increase in pathogenicity. In contrast, kappa-carrageenan oligosaccharides did not induce a marked release of H(2)O(2) from A. operculata but hindered amino acid uptake and enhanced their recognition by the host, resulting in a reduced virulence. Moreover, C. crispus life cycle phases were shown to behave differently in their response to challenge with cell-free extracts of A. operculata. Gametophytes exhibited a large burst of H(2)O(2), whereas only low levels were released from the sporophytes.
Related Concept Videos
Overview of Algae
Red Algae
Green Algae
Diversity of Protists II
Other Algae
Microbial Interactions: Mutualism

