All of the animals (including the human) shown above have a symbiotic relationships with bacteria. The digestive-tract of the medicinal leech, Hirudo medicinalis, is simple in comparison to other animals and dominated by Aeromonas veronii biovar sobria and a Rikenella-like bacterium. This simplicity provides the opportunity to investigate the interaction of the partners. Some animals have special organs where they house the symbionts. A well-studied example is the Hawaiian squid, Euprymna scolopes. The symbiotic bacteria, Vibrio fischeri, produce light and are housed in a light organ. The light produced by the bacteria is used by the squid to camouflage themselves. Other symbioses are so intimate that the symbionts live inside the host cells. An example of this is the symbiosis of Aphids, Aphidoidea. The genomes of the symbionts from the aphid and squid have been sequenced.

Click on the picture to find out more information about these symbioses

Link
Symbiont	Aeromonas veronii Rikenella-like bacterium	Vibrio fischeri	Buchnera species	Xenorhabdus nematophilus
Host	Hirudo medicinalis	Euprymna scolopes	Aphidoidea	Steinernema carpocapsae
Type	Digestive-tract symbiosis	Light Organ symbiosis	Nutritional symbiosis	Digestive-tract symbiosis
Location	Extracellular	Extracellular	Intracellular	Extracellular
Function	Unknown	Light production	Amino Acid Synthesis	Digestion of insect host

 

For each symbiosis, there is a general introductory paragraph, followed by information on the current research and certain other aspects that we find exciting. Direct links to the home pages of investigators are provided, where you can find out more information about them, their research interests, and how to contact them. The reference section lists recent reviews and selected research articles, often with links to the abstract or the online articles.

For a general introduction to the subject of symbiosis and some general articles and links click on symbiosis.

We are continuously improving and updating this site. If you have comments, corrections, links, or suggestions, please send them to us. We are gradually adding descriptions of other symbioses, so come back and visit again.

If your favorite symbiosis is missing, please send us information, pictures, publications and links to the homepages of the investigators.

We would like to express our thanks to the investigators / authors / photographers who have permitted us to use their images. Please do not use any of the images without prior permission.

This web site has been created by Joerg Graf from the Department of Molecular and Cell Biology at the University of Connecticut and Elaine S. Mirkin, a free-lance writer in Willington, CT. We began working on this web site at the Institute for Infectious Diseases of the University of Berne.

© 2007, J.Graf. Last updated November 2006 by Joerg.Graf@uconn.edu