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Zebra
Skeptic Friend
USA
354 Posts |
 Posted - 06/03/2009 : 23:43:42
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Story here about light-sensing properties of non-ocular tissue in some squid, using the same proteins as in the eye.
(h/t to "Carlie" for the link in a comments thread at Pharyngula)
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I think, you know, freedom means freedom for everyone* -Dick Cheney
*some restrictions may apply |
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Kil
Evil Skeptic
USA
13477 Posts |
Posted - 06/04/2009 : 10:55:12 [Permalink]
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Oh that is very cool.
For some reason, I have this feeling that I already heard about that, but I can't remember the source. Maybe it was another animal. |
Uncertainty may make you uncomfortable. Certainty makes you ridiculous.
Why not question something for a change?
Genetic Literacy Project |
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Zebra
Skeptic Friend
USA
354 Posts |
Posted - 06/04/2009 : 23:02:12 [Permalink]
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Maybe a squid told you about it already?
But this does remind me of the 3rd type of light-detecting cell in human retinas. You remember rods and cones, right? Well, it turns out that's not all - there's another type of cell, distinct from rods & cones, which is responsive to light. It sends its projections to the suprachiasmatic nucleus to give "day/night" info (as "light/dark") to the "clock" in our brains. Cooler yet, it uses a different photochemical, melanopsin.
From the Wikipedia page on melanopsin: Melanopsin is a photopigment found in specialized photosensitive ganglion cells of the retina that are involved in the regulation of circadian rhythms, pupillary light reflex, and other non-visual responses to light.
[snip]
Melanopsin differs from other opsin photopigments in vertebrates. In fact, it resembles invertebrate opsins in many respects, including its amino acid sequence and downstream signaling cascade.
[snip]
Melanopsin was originally discovered in 1998 in specialized light-sensitive cells of frog skin by Dr. Ignacio Provencio and his colleagues.[2] In 1999 Dr. Russell Foster showed that a third class of photoreceptor existed in mammalian eyes. In 2000, Provencio showed that mammals, including humans, also produce melanopsin and that it is found only in a rare subtype of retinal ganglion cells, the output cells of the retina.
[snip]
[Dr. David Berson and colleagues at Brown University] showed that melanopsin ganglion cells are intrinsically photosensitive[4], thus named intrinsically photosensitive Retinal Ganglion Cells (ipRGC). They constitute a third class of photoreceptors in the mammalian retina, beside the already known rod and cone photoreceptors. |
And once it's discovered, they can't help playing with it:
| Melyan et al. in England in 2005 reported rendering a mouse paraneuronal cell line (Neuro-2a), which normally is not photosensitive, photoreceptive by the addition of human melanopsin. |
Isn't that cool??!
[Alas, I find I wax more enthusiastic about old findings in humans than recent findings in squid. I should be banned from Pharyngula.] |
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How do squid see light? Let us count the ways
