The study of luminescent bacteria in a Hawaii squid might help to explain why certain germs occupy tissues in the human body.

A Hawaii squid that mimics the moonlight on the ocean isn’t born with luminescence in its body.

The Hawaiian bobtail squid attracts a concentration of luminescent bacteria with its body’s fatty acids, according to research by University of Hawaii professor Edward Ruby and his colleagues from the University of Wisconsin at Madison.

The results could help scientists understand the workings of related species such as Vibrio cholera, which causes cholera, and Vibrio vulnificus, which causes necrotizing skin infections and gastroenteritis.

The study found the bacterium Vibrio fischeri has a novel type of receptor that sense the presence and concentration of fatty acids in the squid.

“This is the first example of a receptor for this class of compounds, and this receptor appears to have evolved in, and be restricted to, the Vibrionaceae family of marine bacteria,” Ruby said in a UH news release Tuesday.

The study was published in the journal Applied and Environmental Microbiology.

Scientists have found that by sending and receiving chemical signals, the bacteria communicate with other organisms to determine with which to create a mutually beneficial partnership.

By capturing Vibrio fischeri from surrounding seawater in their light organs, the squid can fool predators such as monk seals, who mistake it for the moon’s reflection.

Rudy and his colleagues plan to continue to try and discover what attracts Vibrio fischeri to the light organ of a squid, in an attempt to understand what attracts microbes to occupy certain tissues of the human body such as the gut, skin, teeth and reproductive tract.

In the future, Ruby and colleagues will continue to try and discover the attractants that allow Vibrio fischeri to be the only bacterial species that can colonize the light organ of the squid. With only one species to track, it is easier to study the colonization process than when there are dozens or hundreds of bacterial species present, as with the intestines.

Ruby is with UH-Manoa’s Pacific Biosciences Research Center.