Showing posts with label squid. Show all posts
Showing posts with label squid. Show all posts

Thursday, August 11, 2016

First Photo of Intact Giant Squid, 1874

reposted

First Photo of Intact Giant Squid, 1874

Moses Harvey’s photograph brought the mysterious creature out of legend and into science.
By  | July 1, 2016
AddThis Sharing Buttons
LAID OUT: The first photograph of most of a giant squid, now displayed in the Smithsonian National Museum of Natural History, was taken for amateur naturalist Moses Harvey of St. John’s, Newfoundland, in 1874. The 27-foot-long carcass (along with this photo of its arms draped on a rail over a bathtub) made its way to zoologist Addison Emery Verrill, who took detailed notes on the specimen. “The tub is 38½ inches in diameter,” he noted on the image. “On the club of the long arm there is a marginal row of small suckers on each side alternating with the larger ones.” Harvey displayed more awe. “I knew that I had in my possession what all the savants in the world did not,” he wrote in his journal. “A photograph could not lie and would silence the gainsayers.”WIKIMEDIA COMMONSIn Portugal Cove, Newfoundland, a small fishing boat was attacked in the fall of 1873. One of the boat’s occupants—so the story goes—saw vast tentacles rising up from the water and, in an act of heroism, hacked a couple off. Boat freed, the fishermen headed back to shore.
The anglers fed one tentacle to a dog, according to some accounts; the other, measuring 19 feet in length, they carried to nearby St. John’s, to the home of minister and amateur naturalist Moses Harvey. “Harvey was Presbyterian Irish, incredibly homesick for Ireland, and had lost himself in all things natural,” says Matthew Gavin Frank, who explored Harvey’s life and essays on Newfoundland’s flora and fauna in his 2014 bookPreparing the Ghost. “He was known in St. John’s in the mid- and late 1800s as just being crazy after all things from the land and the sea.” Harvey bought the tentacle for $10, says Frank, and estimated the creature it came from to be 72 feet long.
A subject of cautionary tales rather than scientific inquiry, the giant squid was still very much considered part of mythology, Frank says. But the following year, another group of fisherman in Logy Bay near St. John’s port brought Harvey something unequivocally convincing: a whole giant squid that had died thrashing in their nets. “These fisherman had obviously heard that Harvey had paid $10 for a tentacle and thought, ‘Well, goodness, what will he pay for the entire thing?’” Frank says. “The answer was also $10.”
Harvey took the specimen back to his house at 3 Devon Row and draped its 27-foot-long body over a curtain rod above the bathtub. He arranged its tentacles, set up a photograph of the cephalopod hanging from the rail, and then relegated the animal to a vat of brine in the back yard.
News of the squid quickly spread, and “around the globe, Harvey’s photograph was immediately, even by scientists, referred to as ‘the problem of the giant squid,’” Frank says. “The problem, of course, was that now it was real.” While scientists attempted to reconcile this bizarre creature with their view of the animal kingdom, others, including American showman and circus founder P.T. Barnum, began bidding for the carcass.
In the end, Harvey sent his squid to Yale University zoologist Addison Emery Verrill, who was horrified by the specimen’s condition, Frank says. “The carcass had shrunk, desiccated a bit, and some of the suckers had fallen off.” But Verrill went on to publish the world’s first accurate illustrations and descriptions of this hitherto mythical creature.
Still today, nearly 150 years after the photograph was taken, little is known about the ecology of the giant squid. Rarely seen in action, this animal lives at depths of more than 500 meters (1,640 feet), and resists even the most dedicated researchers’ attempts to find it. “The photograph stands as a testament to the fact that this thing still remains, so many years out, so incredibly mysterious,” says Frank. “It’s a source of both frustration and wonder.” 

Friday, July 26, 2013

Groovy Color

reposted from
http://www.the-scientist.com//?articles.view/articleNo/36127/title/Groovy-Color/

Advertisement
Gene Tools
Gene Tools

Groovy Color

To control their color displays, squid fine-tune the optical properties of light-reflecting cells by rapidly expelling and imbibing water across a tightly pleated membrane
By  | July 1, 2013
  • Link this
  • Stumble
EDITOR'S CHOICE IN BIOPHYSICS
LET THERE BE COLOR: Iridocyte membranes consist of lots of tightly packed parallel folds, creating numerous extracellular channels between lamellae containing reflectin proteins (1). The neurotransmitter ACh activates a cascade of signals in the cell that results in reflectin condensation, making the membrane reflective and iridescent (2). Ions released by the condensation of reflectins cross the membrane into the extracellular space, which in turn drives the expulsion of water from lamellae (3). This shrinks the lamellae, changing the thickness of and spacing between the membrane’s deep grooves to reflect light in a variable way that produces colors (4).© SCOTT LEIGHTONThe paper
D.G. DeMartini et al., “Membrane invaginations facilitate reversible water flux driving tunable iridescence in a dynamic biophotonic system,” PNAS, 110:2552-56, 2013.

From hummingbirds to herring, a dazzling range of animals boast structural color—the brilliant iridescent hues that result not from pigment, but from light reflecting off microscale structures in feathers or skin cells. (See “Color from Structure,” The Scientist, February 2013.) However, only a select few cephalopods can rapidly fine-tune their iridescent colors for communication or camouflage. They do so by tweaking the reflective properties of an array of deep grooves in the plasma membranes of specialized cells called iridocytes. But exactly how the membrane is manipulated, and how those changes produce the whole spectrum of colors, has been unclear.
In 2010, Daniel Morse of the University of California, Santa Barbara, and colleagues showed that when the neurotransmitter acetylcholine (ACh) binds to a receptor on iridocytes it triggers a cascade of signals that results in the phosphorylation and consequent condensation of reflective proteins called reflectins. This year, Morse and his team took an even closer look at how the iridocytes respond to activation by ACh.
First, they isolated iridocytes from squid (Doryteuthis opalescens) and examined the cells’ surface using a high-resolution scanning electron microscope. To their surprise, they saw that the grooves on the plasma membrane are made up of a series of tightly packed parallel invaginations that penetrate deep into the cell like pleats in a drape. Dissecting away parts of the cell with an ion beam for a clearer view, they found that this infolding of the membrane creates numerous extracellular channels separating fingerlike lamellae filled with reflectins. Other researchers had thought that the membrane formed discrete discs, “like stacked plates,” says Morse.
The squid tunes its color by altering the thickness of the lamellae and of the extracellular channels between them, which changes how the grooves interact with light. Morse and colleagues hypothesized that lamellar thickness might be altered by a rapid inflow or release of water through the cell membrane. To test the idea, they tracked the movement of deuterium oxide, or heavy water, and found that as water was expelled from the lamellae, the cell changed from its initial nonreflective transparent state to red and then progressively through the spectrum to blue.
Morse’s team already knew that the ACh-activated signal cascade causes reflectins in the transparent lamellae to condense, creating a thick gel that renders the grooves reflective. But their latest results have led the researchers to refine this model by proposing that reflectin condensation may result in the release of ions across the cell membrane, which in turn could drive the expulsion of excess water from the lamellae to maintain electroosmotic equilibrium, resulting in further dehydration and condensation. This exchange increases reflectin concentration and shrinks lamellar thickness, enhancing iridescence and allowing dynamic control of the color of reflected light. The process is completely reversible, so the colors can be fine-tuned at will.
“Their proposed mechanism is interesting,” says Roger Hanlon of the Marine Biology Laboratory in Woods Hole, Massachusetts, who works on color-changing cephalopods. And although there are substantial gaps to fill, he adds, the research has “elevated the discussion significantly.” 
  • Link this
  • Stumble
Advertisement

Add a Comment

Avatar of: You
You
Sign In with your LabX Media Group Passport to leave a comment
Not a member? Register Now!

Follow The Scientist

icon-facebook icon-linkedin icon-twitter icon-vimeo icon-youtube
Advertisement
RayBiotech
RayBiotech
Subscribe to The Scientist

Stay Connected with The Scientist

  • icon-facebookThe Scientist Magazine
  • icon-facebookThe Scientist Careers
  • icon-facebookNeuroscience Research Techniques
  • icon-facebookGenetic Research Techniques
  • icon-facebookCell Culture Techniques
  • icon-facebookMicrobiology and Immunology
  • icon-facebookCancer Research and Technology
Advertisement
ClonTech
ClonTech

Subscribe to RSS feed