[Detection of the quorum sensing signals in methanogenic archaea].

Unlabelled: Methanosaeta harundinacea 6Ac displayed a cell-density dependent cell morphology transition between short rods (3 microm - 5 microm) and filaments ( >200 microm), implying a quorum sensing system in this archaeon.

Objective: This study aimed to confirm that cell morphology related quorum sensing exists in Methanosaeta harundinacea.

Methods: By using the bioassay of Agrobacterium tumefaciens NTL4, we determined the presence of acyl homoserine lactones (AHLs) in the spent cultures of Methanosaeta harundinacea 6Ac and other three methanogens. A chemical synthetic AHL, N-(beta-Ketooctanoyl)-L-homoserine lactone was added into the culture of short rods to detect the morphology change.

Results: We determined that AHLs were produced by Methanosaeta harundinacea, Methanosarcina mazei, Methanothermobacter thermautotrophicus and Methanobacterium formicicum. Addition of N-(beta-Ketooctanoyl)-L-homoserine lactone into the culture of Methanosaeta harundinacea 6Ac stimulated the formation of filamentous cells.

Conclusion: This study indicates that AHL-based quorum sensing may be used by several species of methanogenic Archaea.