Ravenwynd

conspiracy, all things celestial, and a place to get together
 
HomePortalFAQSearchMemberlistUsergroupsRegisterLog in
October 2018
MonTueWedThuFriSatSun
1234567
891011121314
15161718192021
22232425262728
293031    
CalendarCalendar
Navigation
 Portal
 Index
 Memberlist
 Profile
 FAQ
 Search
Forum
Affiliates
free forum
 
Search
 
 

Display results as :
 
Rechercher Advanced Search

Share | 
 

 Glow-in-the-Dark Shark Turned on by Hormones

Go down 
AuthorMessage
PassingThrough
Admin
avatar

Posts : 195
Points : 3699
Join date : 2009-10-31
Location : South Carolina

PostSubject: Glow-in-the-Dark Shark Turned on by Hormones   Fri Nov 06, 2009 10:38 pm

from wired.com

dated 11/6/09

Quote :
The safe answer to how a lantern shark turns its luminescence on and off is: “Any way it wants.” Now researchers have looked into the belly of the beast and found that three hormones act as on-off switches for these glow-in-the-dark sharks. It is the first discovery of hormones controlling bioluminescence in animals, the scientists report in the November 15 Journal of Experimental Biology.

sciencenewsBelgian researchers identified melatonin, prolactin and alpha-MSH, three hormones known to control sharkskin coloration, as key players in setting sharks aglow.

In all animals investigated up to this point, luminescence is triggered by nerve cells. Finding a parallel pathway to bioluminescence — one that’s controlled by hormones, not nerves — strongly supports the notion that light-emitting powers have evolved multiple times in animals, comments marine scientist Jim Gelsleichter of the University of North Florida in Jacksonville, who was not involved in the research.

The light-emitting cells in some sharks aren’t connected to prominent nerve cells, and the slow onset of their glow hinted that something other than nerves were involved. Exposing patches of skin from lantern sharks to hormones and to nerve signaling molecules confirmed that hormones turn on the sharks’ bluish glow.

Melatonin, which in humans is an important hormone for sleep regulation, induced a slow, long-lasting glow in the skin patches that persisted for several hours, researchers show. This light probably serves to camouflage these velvet belly lantern sharks, Etmopterus spinax, counter-illuminating them from below as they descend to darker depths of the sea, says Julien Claes, coauthor of the study with Jérôme Mallefet of the Catholic University of Louvain in Belgium.

Prolactin, which plays a major role in reproductive physiology in people, spurred a quicker shine that lasted up to an hour the scientists report. The prolactin-induced glow might be a means of communication with other sharks and potential mates, the scientists speculate. A third hormone, alpha-MSH, turns the shark’s lights off. Several common nerve signaling molecules had no effect, the researchers found.

In bony fishes, nerves control luminescence and skin coloration — an “on” switch that is speedy and precise, allowing very fine-tuned control, notes Gelsleichter. A flounder, for example, that’s moved from a light to a dark background quickly changes color to match the backdrop. “If you put it on a checkerboard, it would probably turn checkerboard, there’s such fine nervous control and it’s very quick,” he says.

But in sharks and the closely related rays, hormones control skin coloration. Like luminescence, this color change is “slower and not as finely regulated,” says Gelsleichter. “If you take a stingray from a light background and put him against a dark background — it will take him a little longer. He’ll almost get it right.”

Even if melatonin doesn’t allow super fine-tuning, it’s actually a very good choice for regulating light for the sharks. Known as the “dark hormone” for its role in sleep and in seasonal shifts in animal physiology and behavior, melatonin is released by the pineal gland, which receives information about the amount of light in the external environment. Many animals secrete more melatonin when the long nights of winter arrive. Similarly, whenever a shark descends it will encounter darker waters, so a hormone that already is tuned into the dark is an ideal one to co-opt for turning on light, notes Seppo Saarela of the University of Oulu in Finland.

While Claes says he is reluctant to generalize, he suspects that other bioluminescent sharks also have hormone switches in their light-producing organs, the photophores. About one in eight shark species does some kind of glowing, says Claes, and he intends to investigate other species. “It’s amazing — this work just shows that bioluminescence is a very complex phenomenon. We are still really at the beginning of this story.”

Video: NOAA




http://www.wired.com/wiredscience/2009/11/glowing-lantern-shark/
Back to top Go down
http://ravenwynd.forumotion.net
PassingThrough
Admin
avatar

Posts : 195
Points : 3699
Join date : 2009-10-31
Location : South Carolina

PostSubject: Re: Glow-in-the-Dark Shark Turned on by Hormones   Fri Nov 06, 2009 10:39 pm

Back to top Go down
http://ravenwynd.forumotion.net
DestroyerOfLies

avatar

Posts : 10
Points : 3106
Join date : 2010-04-28

PostSubject: Re: Glow-in-the-Dark Shark Turned on by Hormones   Thu Apr 29, 2010 11:41 pm

Yes, but... Aren't we ALL "turned on by hormones"?

Laughing
Back to top Go down
PassingThrough
Admin
avatar

Posts : 195
Points : 3699
Join date : 2009-10-31
Location : South Carolina

PostSubject: Re: Glow-in-the-Dark Shark Turned on by Hormones   Fri Apr 30, 2010 7:52 pm

Aye, we're controlled by hormones... but perhaps more turned on by pheromones...

LOL that opens up a whole topic in and of itself...
Back to top Go down
http://ravenwynd.forumotion.net
Sponsored content




PostSubject: Re: Glow-in-the-Dark Shark Turned on by Hormones   

Back to top Go down
 
Glow-in-the-Dark Shark Turned on by Hormones
Back to top 
Page 1 of 1
 Similar topics
-
» Nightime TV glow
» I was Helen of Troy feeding shark fins to the poor
» Dream about big old dark house with government secrets
» Bitter turned to Sweet
» Unique study - Shots in the Dark - Japan, Zen and the West - about reinforcing myths

Permissions in this forum:You cannot reply to topics in this forum
Ravenwynd :: General Ruminations :: News :: Science/Discoveries-
Jump to: