(Press-News.org) Most people don't think worms are cool. But the tiny flatworm that Northwestern University scientist Christian Petersen studies can do something very cool indeed: it can regenerate itself from nearly every imaginable injury, including decapitation. When cut in half, it becomes two worms.
This amazing ability of the planarian flatworm to regenerate its entire body from a small wedge of tissue has fascinated scientists since the late 1800s. The worms can regrow any missing cell or tissue -- muscle, neurons, epidermis, eyes, even a new brain.
Now Petersen and colleague Peter Reddien of the Massachusetts Institute of Technology (MIT) have discovered that an ancient and seldom-studied gene is critical for regeneration in these animals. The findings may have important ramifications for tissue regeneration and repair in humans.
The gene, called notum, plays a key role in the regeneration decision-making process. Protein from this gene determines whether a head or tail will regrow at appropriate amputation sites, the researchers found.
"These worms are superstars in regeneration, and we want to learn how they restore missing body parts," said Petersen, an assistant professor of molecular biosciences in Northwestern's Weinberg College of Arts and Sciences. "We anticipate that understanding the details of how regeneration occurs in nature will ultimately have a broad impact on the repair of human tissue."
The study is published in the May 13 issue of the journal Science. Petersen, a former postdoctoral fellow in Reddien's lab, is the first author. Reddien, associate professor of biology at MIT and the Whitehead Institute for Biomedical Research, is the other author.
The ability of planarians to regenerate any missing tissues after injury depends on a pool of adult stem cells. Researchers hope that by studying this worm they will understand the molecular processes that naturally allow stem cell-mediated tissue repair in higher animals.
In their paper, Petersen and Reddien show that the gene notum is critical for head regeneration in planarians. Inactivation of notum caused animals to regenerate a tail instead of a head, creating two-tailed animals.
"Injuries can alter tissues in many different ways, so regenerating animals must have robust systems that specify restoration of appropriate structures," Petersen said. "Our results suggest that the animals 'decide' what needs to be regenerated, in part, by using cues that indicate axis direction with respect to the wound."
Planarians are 2 to 20 millimeters in size and have a complex anatomy with around a million cells. They live in freshwater ponds and streams around the world. The worm's genome has been sequenced, and its basic biology is well-characterized, making planarians popular with scientists.
Petersen and Reddien also found that notum controls a widely used biochemical circuit, Wnt signaling, in order to promote proper regeneration. This ancient signaling circuit operates in all animals and controls many processes in development and disease, including tissue repair and cancer progression.
In the paper, the authors describe how the gene notum acts at head-facing wounds as a dimmer switch to dampen the Wnt pathway and promote head regeneration. When the head or tail of a planarian is cut off, Wnt is activated. This Wnt activity turns on notum, but only at head-facing wounds. In a feedback loop, notum then turns Wnt down low enough that it can no longer prevent a head from forming. In tail-facing wounds, however, notum is not activated highly, a condition that promotes tail regrowth. (It takes the worm about a week to regrow a head or tail.)
The researchers are intrigued by this new role for notum. Like the Wnt signaling pathway, notum is highly conserved throughout species, from sea anenomes to fruit flies to humans, but little is known about its roles in biology. Because both notum and the Wnt signaling pathway are so evolutionarily ancient, their interaction in planarians may indicate a relationship that is important in other animals as well.
"We anticipate that this phenomenon of feedback inhibition regulating the levels of Wnt activity will be seen broadly in other biological contexts," Reddien said. "Wnt signaling is so broadly studied and important in biology, including for tissue repair and regeneration. Notum isn't really on the map for the broad roles Wnt signaling plays in tissue repair, but this work demonstrates the central role it can play."
The name of the paper is "Polarized Activation of Notum at Wounds Inhibits Wnt Signaling to Promote Planarian Head Regeneration."
CHESTNUT HILL, MA (5/16/2011) – The visual power of a brand can be the first breakthrough companies make with their customers. But efforts to artistically manipulate the typeface of a corporate logo can backfire for firms, according to a Boston College researcher.
Consumers may perceive companies that use incomplete typeface logos — such as the horizontal baby blue stripes that form the letters IBM — as innovative. However, these firms run the risk of being viewed as untrustworthy, according to a report forthcoming in the July issue of the Journal of Marketing.
The City of Akron, OH is launching RingGo Pay by Cell Phone service beginning May 17, 2011. In collaboration with Ampco System Parking, Akron's parking operator, the new service is available for all of the city's on street meters and its downtown parking lots.
This state-of-the-art system will make paying for parking far more convenient for Akron's residents and visitors. Instead of hunting for quarters or standing in snow-covered streets to insert coins or a credit card in a meter or pay station, drivers simply dial the access phone number from their cell phones -- ...
ALBUQUERQUE, N.M. – Researchers at Sandia National Laboratories have developed a super-resolution microscopy technique that is answering long-held questions about exactly how and why a cell's defenses fail against some invaders, such as plague, while successfully fending off others like E.coli. The approach is revealing never-before-seen detail of the cell membrane, which could open doors to new diagnostic, prevention and treatment techniques.
"We're trying to do molecular biology with a microscope, but in order to do that, we must be able to look at things on a molecular ...
New Rochelle, NY, May 16, 2011—Ongoing, intrinsic brain activity that is not task-related accounts for the majority of energy used by the human brain. This surprising finding, along with other recent discoveries about the brain and its function, structure, and organization, are described in "The Restless Brain," an Instant Online article in the groundbreaking new neuroscience journal Brain Connectivity, a bimonthly peer-reviewed journal published by Mary Ann Liebert, Inc. (www.liebertpub.com). "The Restless Brain," seven additional articles from the first issue, and a full ...
To celebrate the launch of RakeTheRake's new website, there are three months of unique promotions to be won. Every week from now until the end of July 2011, there are some truly amazing prizes on offer for online poker players, all generously provided by RakeTheRake and their poker room friends. These special promotions are in addition to the regular $500k+ of monthly promotions. What's more, even players not currently tracked to RakeTheRake can enter!
This week there's the chance to win an incredible two day hospitality package to the Monaco Grand Prix in May 2012 thanks ...
ROOTSTOWN, Ohio—May 16, 2011—Ohioans broadly support a strong commitment to medical and health research and recognize its direct link to job creation and the state's and the nation's economy, according to a new statewide poll conducted by IBOPE Zogby for Research!America and Northeast Ohio Medical University (NEOMED).
A strong majority of Ohioans (86%) thinks medical and health research is important—42% say very important—to the state's economy. Eight in 10 believe spending money on scientific research is important to Ohio's economy in terms of jobs and incomes.
An international team of researchers, led by scientists at the University of California, San Diego School of Medicine, and the Eastern Hepatobiliary Surgery Hospital in China, say a human gene implicated in the development of leukemia also acts to prevent cancer of the liver.
Writing in the May 17 issue of the journal Cancer Cell, Gen-Sheng Feng, PhD, UCSD professor of pathology, and colleagues in San Diego, Shanghai and Turin report that an enzyme produced by the human gene PTPN11 appears to help protect hepatocytes (liver cells) from toxic damage and death. Conversely, ...
Corners of Time, a gourmet Mediterranean online marketplace, announces a first of its kind collaboration between Lebanon and California. In order to insure top quality olive oil and olive oil based products for its customers, Corners of Time has brought Lebanese olive tree cuttings into the United States. They are currently USDA quarantined at Novavine, an expert olive and grape nursery located in Sonoma County.
Four thousand years later, Corners of Time is completing the 16th century BC mission of its Lebanese ancestors, those adventurous Phoenician sailors who spread ...
OAK RIDGE, Tenn., May 16, 2011 – Billions of dollars lost each year as waste heat from industrial processes can be converted into electricity with a technology being developed at the Department of Energy's Oak Ridge National Laboratory.
The high-efficiency thermal waste heat energy converter actively cools electronic devices, photovoltaic cells, computers and large waste heat-producing systems while generating electricity, according to Scott Hunter, who leads the development team. The potential for energy savings is enormous.
"In the United States, more than 50 percent ...
Scientists at the University of Washington (UW) Department of Genome Sciences have identified several sporadic or "de novo" genetic mutations in children with autism spectrum disorder. The researchers applied leading edge molecular biology techniques and massively parallel sequencing to simultaneously examine all of the protein coding portions of the genome, collectively called the exome.
The research was published in advance online Sunday, May 15, in Nature Genetics.
The study was led by Dr. Brian O'Roak, senior fellow in the UW Department of Genome Sciences, and ...