The Year in Science: Biology

Giant squid sighting, mice that regenerate body parts, sweet-smelling parasites, and more.

Monday, January 09, 2006

Japanese Photograph Elusive, Strong, and Not-So-Gentle Giant

Elusive monsters have long been the inspiration for sea tales. Yet the only confirmed sightings of anything approaching that status have been squid washed ashore dead and dying or caught in fishermen's nets. This year that changed. Two Japanese researchers published the first photos of a giant squid in the wild.

Between 2002 and 2004, Tsunemi Kubodera of the National Science Museum in Tokyo and Kyoichi Mori of the Ogasawara Whale Watching Association set out to succeed where better-funded projects had failed. The pair used only a five-ton fishing boat manned by two crew members. Patience and cunning helped: Kubodera suspects the giants, or Architeuthis dux, were scared off by more overt efforts to find them. "We waited for the squid to come to us," he says.

The team made three trips to sperm-whale hunting grounds 600 miles south of Tokyo. They used data on the predator's hunting patterns to work out where to sink their 3,000-foot line, which they baited with a common Japanese squid and mashed shrimps. They attached a camera and flash. On the morning of September 30, 2004, on their 23rd attempt, they got their reward: a giant squid wrapped two long tentacles around the bait, snagging itself in the process. For the next four hours, as the squid fought for freedom, the camera took more than 550 images. And when Kubodera and Mori retrieved the line, there was a souvenir—an 18-foot-long tentacle still able to grip the ship's deck and Kubodera's fingers.

Back in the lab, DNA analysis confirmed that the tentacle belonged to Architeuthis. Researchers calculated the monster's length at about 26 feet, roughly half that of a sperm whale. When they uploaded images from the camera, they found that their subject was not the gentle giant some academics had supposed. The squid taking the bait, says Kubodera, was like "a large snake enveloping and holding its prey."  —Tony McNicol 

Mystery Mice Regenerate Body Parts

This year, a researcher who had shown that a specially bred strain of mouse can regrow parts of its ear and heart claimed that it can regenerate other parts, including bits of the tail, optic nerve, and even toes. Ellen Heber-Katz, an immunologist at the Wistar Institute at the University of Pennsylvania, came upon the peculiar animals when she ordered lab mice bred for studying the overactive immune response in lupus. She described her findings at a conference in September at Cambridge University in England. Holes punched into the ears to tag the mice, she says, healed without any signs of scar tissue. She speculates that the capability could have emerged by chance after generations of breeding and inbreeding for mice used in special experiments.

Heber-Katz also says her experiments show healing in the tail and the optic nerve.  She says she has seen some remarkable healing in the toe of a mouse, where some bone and cartilage has grown, and "there is a hint of a joint" growing, she says. Those results have not been published.

Heber-Katz observed two mechanisms for healing. One is a breakdown after injury of the so-called basement membrane, a layer between the epidermis and the dermis that normally keeps tissues separate. When that layer disappears, proteins in the epidermis and the dermis interact and stimulate cell division, a process that also occurs in salamanders when they regenerate their limbs and tails. The second mechanism involves collagen, a tissue associated with scarring. In these mice, collagen made after an injury does not crosslink into a mass, so no scar tissue forms to halt cell migration and division.

Although the mice seem remarkable, many other mammals have shown exceptional healing abilities, especially in areas like the ends of the fingers. Even humans have an impressive capacity for fingertip healing.

Anthony Mescher, a cell biologist at the Indiana University School of Medicine with expertise in amphibian regeneration, thinks Heber-Katz's mice do repair injuries better than ordinary mice. "But as far as the digits, it may not be dramatically different from what an ordinary mouse can do. It's certainly interesting but still preliminary," he says.  —Susan Kruglinski

Life Turns Up In the Most Unlikely Places

2005 proved a banner year for microbes, the world's oldest and most abundant inhabitants. Intrepid researchers turned up new organisms that offer proof of life's ability to take root in four extreme environments.

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