Hokkaido University Research Profiles

Arctic Research

Glowing Plankton

GFP and luciferase in copepods

Marine organisms include various bioluminescent creatures. We have identified a green fluorescent protein (GFP) and a secreted luciferase (luminescent enzyme) from copepods, the most dominant plankton species.

Content of research

Zooplankton serves as energy transmitters in marine ecosystems, passing basic production to higher organisms. The dominant zooplankton species in the Arctic Ocean are copepods, most of which have a lifespan of one year or less, but their samples can be preserved semi-permanently with formalin fixation, making them an ideal taxonomic group for assessing the interannual variability in biological production in the region. Some species of copepods are also bioluminescent. It is thought that they emit light when they are about to be predated upon in dark waters, and use it to distract predators. We have identified a fluorescent protein (GFP) and a luciferase (luminescent enzyme) from copepods.

  • Comparison between 1991/92 and 2007/08 shows that the Arctic Ocean community (Community B in the left figure) is being replaced by a subarctic community (Community A), which includes species from the Pacific Ocean, due to the recent decline of sea ice in the Arctic Ocean. The photos on the right show a species with GFP (top) and luciferase (middle), and a bright field photo of a caecilian (bottom).

Potential for social implementation

  • ・Hikaru Hana (glowing flowers, developed by NEC Solutions Innovator, Ltd.)
  • ・Application as a reporter protein

Appealing points to industry and local governments

The Caenorhabditis elegans luciferase cloned by our research group (in collaboration with the Institute of Advanced Industrial Science and Technology (AIST)) is thermostable, and its luminescence spectrum does not change with changes in pH, making it an excellent extracellular reporter protein.