Bobtail squid coat their eggs in antifungal goo

Females have a special organ that houses protective bacteria for the jellylike coating

Hawaiian bobtail squid

BOBTAIL BACTERIA  Hawaiian bobtail squid have a secret weapon to protect their eggs and offspring: fungus-fighting bacteria.

M. McFall-Ngai/PLOS Biology 2014

MADISON, Wis. — When eggs go bad, bacteria usually get the blame. But some bacteria help bobtail squid keep their eggs fresh.

Bacteria that female Hawaiian bobtail squid (Euprymna scolopes) deposit in the jelly surrounding their eggs can fight off a fungus called Fusarium keratoplasticum, Spencer Nyholm reported July 9 at the Beneficial Microbes Conference.

A specialized organ called the accessory nidamental gland is found only in female bobtail squid and other cephalopods. The organ houses bacteria, mostly varieties of Rhodobacteraceae and Verrucomicrobia, and helps coat eggs with a thick layer of protective jelly impregnated with the microbes.

Nyholm, of the University of Connecticut in Storrs, and colleagues treated squid eggs with antibiotics to kill the bacteria. The eggs grew fuzzy with fungus, and the developing squid embryos soon died.

Bacteria from the accessory nidamental gland make several types of antifungal chemicals, including some that haven’t been characterized before, the researchers discovered. Some of those antifungal chemicals also inhibited growth of some bacteria and other fungi, including Candida albicans, a type of fungus that causes infections in humans. Squid bacteria may one day be a source of new kinds of natural antibiotics or antifungal drugs, Nyholm says.

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

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