Fluorescence
Hydrozoans have become known for the discovery of green fluorescent protein (GFP). This protein was first isolated from the hydrozoa Aequorea victoria, which also belongs to the order Leptothecata. GFP is now commonly used as a genetic marker by molecular biologists.
The presence of GFP was tested for on this hydromedusa by shining ultraviolet light on a fresh species. Below are two pictures of different species found in the same plankton tow. On the left is the species being studied and on the right is another species of Leptothecata. While they both display the presence of GFP, the difference in patterning can clearly be seen.
A close up of one of the tentacles was observed for GFP and red fluorescence. The root of the tentacle showed a few areas of red fluorescence while the GFP was seen everywhere.
A long exposure compound image of the GFP seen in the species of Leptothecata
DAPI is a fluorescent stain that is used to stain DNA in the nucleus by binding to A-T rich regions. It is a handy tool to distinguish between individual cells by giving off a blue glow when ultraviolet light is used. This picture shows a high number of cells in the tentacles and outer region and very few in the mesoglea.
BODIPY-Phalloidin is a bicyclic peptide that binds to actin giving off a green fluorescence under ultraviolet light. Actin is a protein found in muscle cells which allows the muscles to contract. By using this stain, it is possible to see where the muscles are located in the medusa.
DAPI BODIPY-Phalloidin |