Navigation Links
For fish, fear smells like sugar

When one fish gets injured, the rest of the school takes off in fear, tipped off by a mysterious substance known as "Schreckstoff" (meaning "scary stuff" in German). Now, researchers reporting online on February 23 in the Cell Press journal Current Biology have figured out what that scary stuff is really made of.

Within that chemical brew is a special type of sugar found in abundance in fish skin. When a fish is wounded, fragments of the sugar known as chondroitin sulfate alarm other fish nearby.

"Our results provide a solution to a 70-year-old puzzle: the nature of this alarm signal," says Suresh Jesuthasan of A*Star's Neuroscience Research Partnership and the Duke/National University of Singapore Graduate Medical School in Singapore.

Chondroitin sulfate is a major component of fish skin, he said, and its breakdownlikely triggered by enzymes released upon injuryseems to be the key.

The new study shows that Schreckstoff and these sugar fragments register in a particular part of the zebrafish brain. That region in the scent-processing olfactory bulb includes an enigmatic class of sensory neurons known as crypt cells.

The researchers suggest that those neurons may be specialized to detect the sugary alarm cue. "This region of the olfactory bulb has unique projections to higher centers of the brain," Jesuthasan says, "so there may be a special circuit mediating aspects of the innate fear response."

The findings identify a new class of odorants for fish. It also helps to explain how this "danger" signal might have evolved even though the signal offers no particular benefit to its sender. Those sugar fragments are naturally released upon injury, whether anyone can smell them or not. Fish able to pick up the scent and flee are more likely to survive and reproduce.

Puzzles remain, however. For instance, some fish species will sense alarm cues released from closely related species but respond less intensely to cues from more distant relatives. The trend suggests that chondroitin fragments may come in a variety of "flavors," and the researchers are now interested in testing whether the same fragments that breed fear in zebrafish will elicit responses in other species as well.

Ultimately, the discovery could lead to new insight into the nature of fear itself.

"These findings underscore the usefulness of the zebrafish as a system to investigate the neural basis of innate fear," Jesuthasan said. "Given the transparency of larval fish, it is possible to see at single-cell resolution what happens throughout the brain when the organism detects danger. This will allow us in the future to ask how neurons, as a group, regulate behavior and emotional responses."


Contact: Elisabeth (Lisa) Lyons
Cell Press

Related biology news :

1. A small step for lungfish, a big step for the evolution of walking
2. One fish, two fish reef fish
3. One fish, two fish … reef fish
4. Magnetic attraction for fish, crabs?
5. Undesirable evolution can be reversed in fish, Stony Brook University scientists show
6. UNH researchers studying spiny dogfish, Gulf of Maines mini shark
7. Historical photographs expose decline in Floridas reef fish, new Scripps study finds
8. Ocean fish farming harms wild fish, study says
9. Carbonized coffee grounds remove foul smells
10. Smells may help birds find their homes, avoid inbreeding
11. Researchers unlock new secret to how smells are detected
Post Your Comments:
(Date:10/27/2015)... BERLIN, Germany , October 27, 2015 ... 2015. SMI,s Automated Semantic Gaze Mapping technology (ASGM) automatically ... SMI,s Eye Tracking Glasses , so that ... Suite BeGaze. --> Munich, Germany ... technology (ASGM) automatically maps data from mobile eye tracking ...
(Date:10/26/2015)... LAS VEGAS , Oct. 26, 2015 /PRNewswire/ ... innovator in modern authentication and a founding member of ... of its latest version of the Nok Nok™ S3 ... use standards-based authentication that supports existing and emerging methods ... is ideal for organizations deploying customer-facing applications that require ...
(Date:10/23/2015)... and GOLETA, California , October 23, ... BIOPAC and SensoMotoric Instruments (SMI) announce a mobile plug ... data captured during interactive real-world tasks SensoMotoric ... integration of their established wearable solutions for eye tracking ... gaze behavior captured with SMI Eye Tracking Glasses ...
Breaking Biology News(10 mins):
(Date:11/30/2015)... JACKSONVILLE, Florida , November 30, 2015 ... company specializing in the development of innovative peptide and ... & metastatic disease, today announced it will be presenting ... Event on December 1, 2015 at 2.30 PM PT. ... member and Strategic Advisor will be giving the presentation ...
(Date:11/30/2015)... Md. , Nov. 30, 2015  Northwest Biotherapeutics ... company developing DCVax® personalized immune therapies for solid tumor ... adding an additional independent director, and the Company welcomes ... of allegations in a recent anonymous internet report on ... both initiatives. Linda Powers stated, "We ...
(Date:11/27/2015)... ... November 27, 2015 , ... ... that includes over 2,000 technical presentations offered in symposia, oral sessions, workshops, awards, ... spectroscopy, covers a wide range of applications such as, but not limited to, ...
(Date:11/25/2015)... Nov. 25, 2015  PharmAthene, Inc. (NYSE MKT: PIP) ... a stockholder rights plan (Rights Plan) in an effort ... carryforwards (NOLs) under Section 382 of the Internal Revenue ... PharmAthene,s use of its NOLs could be substantially ... defined in Section 382 of the Code. In general, ...
Breaking Biology Technology: