Topics on Life Sciences
Chronicle Editor @ Sep 25, 2008
view in one page and print
a) Biologists on the Verge of Creating New Form of Life
By Alexis Madrigal September 08, 2008 | 10:30:34 AM Categories: Biology
A team of biologists and chemists is closing in on bringing non-living matter to life.
It's not as Frankensteinian as it sounds. Instead, a lab led by Jack Szostak, a molecular biologist at Harvard Medical School, is building simple cell models that can almost be called life.
Szostak's protocells are built from fatty molecules that can trap bits of nucleic acids that contain the source code for replication. Combined with a process that harnesses external energy from the sun or chemical reactions, they could form a self-replicating, evolving system that satisfies the conditions of life, but isn't anything like life on earth now, but might represent life as it began or could exist elsewhere in the universe.
While his latest work remains unpublished, Szostak described preliminary new success in getting protocells with genetic information inside them to replicate at the XV International Conference on the Origin of Life in Florence, Italy, last week. The replication isn't wholly autonomous, so it's not quite artificial life yet, but it is as close as anyone has ever come to turning chemicals into biological organisms.
"We've made more progress on how the membrane of a protocell could grow and divide," Szostak said in a phone interview. "What we can do now is copy a limited set of simple [genetic] sequences, but we need to be able to copy arbitrary sequences so that sequences could evolve that do something useful."
By doing "something useful" for the cell, these genes would launch the new form of life down the Darwinian evolutionary path similar to the one that our oldest living ancestors must have traveled. Though where selective pressure will lead the new form of life is impossible to know.
"Once we can get a replicating environment, we're hoping to experimentally determine what can evolve under those conditions," said Sheref Mansy, a former member of Szostak's lab and now a chemist at Denver University.
Protocellular work is even more radical than the other field trying to create artifical life: synthetic biology. Even J. Craig Venter's work to build an artificial bacterium with the smallest number of genes necessary to live takes current life forms as a template. Protocell researchers are trying to design a completely novel form of life that humans have never seen and that may never have existed.
Over the summer, Szostak's team published major papers in the journals Nature and the Proceedings of the National Academy of Sciences that go a long way towards showing that this isn't just an idea and that his lab will be the first to create artificial life -- and that it will happen soon.
"His hope is that he'll have a complete self-replicating system in his lab in the near future," said Jeffrey Bada, a University of California San Diego chemist who helped organize the Origin of Life conference.
Modern life is far more complex than the simple systems that Szostak and others are working on, so the protocells don't look anything like the cells that we have in our bodies or Venter's genetically-modified E. coli.
"What we're looking at is the origin of life in one aspect, and the other aspect is life as a small nanomachine on a single cell level," said Hans Ziock, a protocellular researcher at Los Alamos National Laboratory.
Life's function, as a simple nanomachine, is just to use energy to marshal chemicals into making more copies of itself.
"You need to organize yourself in a specific way to be useful," Ziock said. "You take energy from one place and move it to a place where it usually doesn't want to go, so you can actually organize things."
More >>
____________________________________________________________________
b) Cells change identity in promising breakthrough
Graphic explains how scientists were able to change a pancreas cell into an insulin-producing cell; |
Cells change identity in promising breakthrough
By MALCOLM RITTER – Aug 27, 2008
NEW YORK (AP) — Talk about an extreme makeover: Scientists have transformed one type of cell into another in living mice, a big step toward the goal of growing replacement tissues to treat a variety of diseases.
The cell identity switch turned ordinary pancreas cells into the rarer type that churns out insulin, essential for preventing diabetes. But its implications go beyond diabetes to a host of possibilities, scientists said.
It's the second advance in about a year that suggests that someday doctors might be able to use a patient's own cells to treat disease or injury without turning to stem cells taken from embryos.
The work is "a major leap" in reprogramming cells from one kind to another, said one expert not involved in the research, John Gearhart of the University of Pennsylvania.
That's because the feat was performed in living mice rather than a lab dish, the process was efficient and it was achieved directly without going through a middleman like embryonic stem cells, he said.
The newly created cells made insulin in diabetic mice, though they were not cured. But if the experiment's approach proves viable, it might lead to treatments like growing new heart cells after a heart attack or nerve cells to treat disorders like ALS, formerly Lou Gehrig's disease.
Douglas Melton, co-director of the Harvard Stem Cell Institute and a researcher with the Howard Hughes Medical Institute, cautioned that the approach is not ready for people.
He and his colleagues report the research in a paper published online Wednesday by the journal Nature.
Basically, the identity switch comes about by a reprogramming process that changes the pattern of which genes are active and which are shut off.
Scientists have long hoped to find a way to reprogram a patient's cells to produce new ones. Research with stem cells, and similar entities called iPS cells that were announced last year, has aimed to achieve this in a two-step process.
The first step results in a primitive and highly versatile cell. This intermediary is then guided to mature into whatever cell type scientists want. That guiding process has proven difficult to do efficiently, especially for creating insulin-producing cells, Gearhart noted.
In contrast, the new method holds the promise of going directly from one mature cell type to another. It's like a scientist becoming a lawyer without having to go back to kindergarten and grow up again, Melton says.
So, he says, someday scientists may be able to replace dead nerve or heart cells in people by converting some neighboring cells. At the same time, he stressed that it's still important to study embryonic stem cells and iPS cells.
The Melton team started its work with pancreas cells that pump out gut enzymes used in digestion and turned them into pancreatic "beta" cells, which make insulin.
The researchers destroyed beta cells in mice with a poison, giving the mice diabetes. Then they injected the pancreas with viruses that slipped into the enzyme-making cells. These viruses delivered three genes that control the activity of other genes.
Just three days later, new insulin-secreting cells started to show up. By a week after that, more than a fifth of the virally infected cells started making insulin. That shows "an amazingly efficient effect," commented Richard Insel, executive vice president of research at the Juvenile Diabetes Research Foundation.
Scientists found evidence that the newcomers were converts from mature enzyme-making cells. They identified the new cells as beta cells by their detailed appearance and behavior, and Melton said they've continued functioning for months.
The new cells didn't fully replenish the insulin supply, but maybe there were too few of them, or they were hampered by not forming clusters like ordinary beta cells do, researchers said.
The work brings "more excitement to the idea of using reprogramming as a way to treat diabetes," said researcher Mark Kay of Stanford University, who is studying the approach with liver cells.
Christopher Newgard, who studies beta cells at Duke University Medical Center, called the work convincing but cautioned that significant scientific questions remained about using the approach in treating disease.
Melton, who began his diabetes research in 1993 when his infant son was diagnosed with the illness, said he's obsessed with trying to find a new treatment or cure for Type 1 diabetes, in which beta cells are destroyed.
"I wake up every day thinking about how to make beta cells," he said.
Melton said he hopes drugs can replace the virus approach because of concern about injecting viruses into people.
As for converting other kinds of cells, scientists noted that the two cell types in the mouse experiment are closely related, and it remains to be shown whether the trick can be achieved with more distant combinations. In any case, scientists would have to deliver different reprogramming signals to other kinds of cells, Melton said.
On the Net:
2 Comment(s) (The views expressed here are those of the commenters, and ITBHUGlobal.org is not responsible for them.)
BARRYMICHELE
said:
Don't have a lot of money to buy a house? Worry not, just because that's achievable to receive the loan to work out such problems. Thence get a auto loan to buy all you need.
May 14, 2010 1:30 AMLeave a comment
(if you having troubles, try posting your comment on this page or send an email to chronicle @ itbhuglobal.org)
Copyright © 2008-2013 by ITBHU Global Alumni Association
Institute of Technology, Banaras Hindu University
Varanasi 221005, UP
Institute of Technology, Banaras Hindu University
Varanasi 221005, UP
great publish, very informative. I'm wondering why the other specialists of this sector don't notice this. You should proceed your writing. I am confident, you have a great readers' base already! auto insurance in virginia
August 11, 2011 9:34 AM