Nissa Edstrom

Thiomargarita is a sulfur oxidizing bacterium that can use nitrate and nitrite as electron acceptors in the absence of oxygen. Along with this, they contain endobionts that share similar metabolism and are in the same clade of endobionts as those in marine siboglinid worms. Why the Thiomargarita endobionts have resorted to the endobiont lifestyle is still relatively unknown. However, based on the clade they belong in, the endobionts could very well be cycling nitrogenous compounds with Thiomargarita. In order to investigate the relationship between these two clades further, culturing them in lab would be ideal. However, currently to date, there is no way to culture either Thiomargarita or its endobionts. This study was done in attempts to cultivate the endobionts. Thiomargarita cells were screened and lysed to obtain endobionts, which were then cultured in liquid media that contained one of five different nitrogen sources: nitrate, nitrite, ammonium, glutamine, or glutamate. From each liquid media (SAB), two phenol red agar plates were made and placed in either a hypoxic chamber or left in room atmosphere followed by streak plating twice for each different colony found. While growing up the cultures, growth was found in both the liquid and agar medias. The agar plates showed signs of acidity, which could potentially mean sulfur oxidizers were present, but the colonies were small and had to be seen under a microscope. We anticipate more time to grow will be needed prior to taxonomic identification via PCR and sanger sequencing.