Salpingoeca rosetta

Salpingoeca rosetta has a sexual cycle during which it transitions between haploid and diploid stages. When nutrients become limiting, haploid cultures of S. rosetta become diploid. This ploidy shift coincides with mating during which small, flagellated cells fuse with larger flagellated cells. Evidence has also been obtained for historical mating and recombination in S. rosetta. Salpingoeca rosetta can be induced to undergo sexual reproduction by the marine bacterium Vibrio fischeri. A single protein of V. fischeri, EroS, fully recapitulates the aphrodesiac-like activity of living V. fischeri. ==Colonial organization==

Salpingoeca rosetta was named for the rosette-shaped colonies formed by its cells. The colonies are held together by adhesion molecules long thought to be found only in Metazoan organisms. Additionally, recent evidence suggests that a bacterial sulfonolipid, called rosette inducing factor (RIF-1) and produced by Algoriphagus machipongonensis, triggers colony formation in S. rosetta. The effect of RIF-1 on colony formation in S. rosetta has been suggested as an example of how interactions between bacteria and eukaryotes may have led to multicellularity in the latter. ==References==