Team:Berkeley/Choanoflagellates

From 2010.igem.org

For our project, we focused on delivering protein to a family of single-celled organisms called choanoflagellates. Choanoflagellates were chosen to demonstrate proof-of-concept because they are extremely easy to culture, proliferate quickly and are applicable to evolutionary research. In a lab culture, choanoflagellates eat dead bacteria, live in sea water, survive at room temperature and do not need to be aerated. In our lab, they were grown in petri dishes with artificial sea water and stored in a desk drawer. They are also incredibly resilient to heat, UV damage and other natural stresses.

In addition, these species are interesting to researchers because they are the closest living relative to our microbial ancestor that became the first multicellular animal. It is believed that choanoflagellates can help reveal some of the key events that were necessary for multi-cellularity to arise. Developmental biologists who study these single-celled eukaryotes, however, are hindered by the inability to genetically manipulate them. Attempts at transfection, electroporation, and retroviral infection have all failed in the past. A mechanism to genetic manipulate choanoflagellates would open an entirely new area of research for developmental biologists. From a synthetic biology perspective though, choanoflagellates' close relationship to animals makes them superior tools compared to bacteria or yeast.

SEM pictures

Choanoflagellates, as seen in blue above, consist of a head and tail region. They can either be found swimming freely, grouped as colonies, or, as seen in the picture above, attached to a substrate. The 'choano' in their name refers to the actin filaments that forms around their long flagellum. Choanoflagellates beat their flagellum to push water and the bacteria they feed on, into their collar. Their voracious appetite for bacteria makes them an easy target for phagocytosis-based infection. The image below shows a choanoflagellate in the process of engulfing its prey.

second SEM picture