Navigation Links
Sensing the light, but not to see
Date:2/6/2013

WOODS HOLE, MASS. -- Among the animals that are appealing "cover models" for scientific journals, lancelets don't spring readily to mind. Slender, limbless, primitive blobs that look pretty much the same end to end, lancelets "are extremely boring. I wouldn't recommend them for a home aquarium," says Enrico Nasi, adjunct senior scientist at the Marine Biological Laboratory (MBL). Yet Nasi and his collaborators managed to land a lancelet on the cover of the Journal of Neuroscience last December. These simple chordates, they discovered, offer insight into our own biological clocks.

Nasi and his wife, MBL adjunct scientist Maria del Pilar Gomez, are interested in phototransduction, the conversion of light by light-sensitive cells into electrical signals that are sent to the brain. The lancelet, also called amphioxus, doesn't have eyes or a true brain. But what it does have in surprising abundance is melanopsin, a photopigment that is also produced by the third class of light-sensitive cells in the mammalian retina, besides the rods and cones. This third class of cells, called "intrinsically photosensitive retinal ganglion cells" (ipRGCs), were discovered in 2002 by Brown University's David Berson and colleagues. Now sometimes called "circadian receptors," they are involved in non-visual, light-dependent functions, such as adjustment of the animal's circadian rhythms.

"It seemed like colossal overkill that amphioxus have melanopsin-producing cells," Nasi says. "These animals do nothing. If you switch on a light, they dance and float to the top of the tank, and then they drop back down to the bottom. That's it for the day." But that mystery aside, Gomez and Nasi realized that studying amphioxus could help reveal the evolutionary history of the circadian receptors.

As so it has. In 2009, Gomez and Nasi isolated the animal's melanopsin-producing cells and described how they transduce light. In their recent paper, they tackled the puzzling question of why the light response of these amphioxus cells is several orders of magnitude higher than that of their more sophisticated, presumed descendents, the ipRGCs. (In mammals, the ipRGCs relay information on light and dark to the biological clock in the hypothalamus, where it is crucial for the regulation of circadian rhythms and associated control of hormonal secretion.)

By detailing how the large light response occurs in the amphioxus cells, Gomez and Nasi could relate their observations to the functional changes that may have occurred as the circadian receptors evolved and "eventually tailored their performance to the requirements of a reporter of day and night, rather than to a light sensor meant to mediate spatial vision." The light-sensing cells of amphioxus, they discovered, may be the "missing link" between the visual cells of invertebrates and the circadian receptors in our own eyes.


'/>"/>

Contact: Diana Kenney
dkenney@mbl.edu
508-289-7139
Marine Biological Laboratory
Source:Eurekalert  

Related biology news :

1. Engineers use droplet microfluidics to create glucose-sensing microbeads
2. First evidence of fish sensing geomagnetic fields from a Czech Christmas market
3. Nutrient-sensing enzymes key to starvation response and survival in newborn mammals
4. Eddies, not sunlight, spur annual bloom of tiny plants in North Atlantic
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Sensing the light, but not to see
(Date:5/3/2016)... VILNIUS, Lithuania , May 3, 2016 /PRNewswire/ ... today released the MegaMatcher Automated Biometric Identification ... deployment of large-scale multi-biometric projects. MegaMatcher ABIS can ... and accuracy using any combination of fingerprint, face ... of MegaMatcher SDK and MegaMatcher ...
(Date:4/28/2016)... , April 28, 2016 Infosys ... (NYSE: INFY ), and Samsung SDS, a global ... that will provide end customers with a more secure, fast ...      (Logo: http://photos.prnewswire.com/prnh/20130122/589162 ) , ... but it also plays a fundamental part in enabling and ...
(Date:4/28/2016)... , April 28, 2016 First quarter 2016: ... up 966% compared with the first quarter of 2015 ... SEK 589.1 M (loss: 18.8) and the operating margin was 40% ... 0.32) Cash flow from operations was SEK 249.9 M ... revenue guidance is unchanged, SEK 7,000-8,500 M. The operating ...
Breaking Biology News(10 mins):
(Date:5/4/2016)... CO (PRWEB) , ... May 05, 2016 , ... ... diagnostics, is proud to support the National Stroke Association during National Stroke Awareness ... the association’s Facebook and Twitter pages throughout the month. CereScan will donate ...
(Date:5/4/2016)... ... May 04, 2016 , ... Looking for a gift ... premiere hands-on cooking experience. Offering everything from gourmet cooking classes to weekend culinary ... forget. , Guests that visit LaJollaCooks4u share an experience unlike any other. Each ...
(Date:5/4/2016)... ... , ... Proove Biosciences, Inc. , the commercial and research leader in ... . The partnership is designed to advance research in pain genetics in an effort ... With the new agreement, researchers at Proove Biosciences are able to collaborate with Luda ...
(Date:5/4/2016)...  Bayer today announced that a Phase III ... (regorafenib) tablets for the treatment of patients with ... endpoint of a statistically significant improvement in overall ... and safety of regorafenib in patients with HCC ... The safety and tolerability were generally consistent with ...
Breaking Biology Technology: