Tuesday, September 8, 2009
Monday, August 3, 2009
BER350 Tutorials........
Dear All,
As most of us have classes or practicals on all days of d week........wat i suggest is that we can hav BER350 in the evening at 5pm on ne dy of the week.........do reply which day do you think will be the best for all...........
As most of us have classes or practicals on all days of d week........wat i suggest is that we can hav BER350 in the evening at 5pm on ne dy of the week.........do reply which day do you think will be the best for all...........
Thursday, May 21, 2009
How RNA got started
Scientists may have figured out the chemistry that sparked the beginning of life on Earth.
The new findings map out a series of simple, efficient chemical reactions that could have formed molecules of RNA, a close cousin of DNA, from the basic materials available more than 3.85 billion years ago, researchers report online May 13 in
Nature.
“This is a very impressive piece of work — a really excellent analysis,” comments chemist James Ferris of the Rensselaer Polytechnic Institute in Troy, N.Y.
The new research lends support to the idea that RNA-based life-forms were the first step toward the evolution of modern life. Called the RNA world hypothesis, the idea was first proposed some 40 years ago. But until now, scientists couldn’t figure out the chemical reactions that created the earliest RNA molecules.
Today, DNA encodes the genetic blueprint for life — excluding some viruses, for those who consider viruses living — and RNA acts as an intermediary in the process, making protein from DNA. But most scientists think it’s unlikely that DNA was the basis of the origin of life, says study coauthor John Sutherland of the University of Manchester in England.
Information-bearing DNA holds the code needed to put proteins together, but at the same time, proteins catalyze the reactions that produce DNA. It’s a chicken-or-egg problem. Scientists don’t think that DNA and proteins could have come about independently — regardless of which came first — and yet still work together in this way.
It’s more plausible that the first life-forms were based on a single molecule that could replicate itself and store genetic information — a molecule such as RNA (SN: 4/7/01, p. 212). RNA world proponents speculate modern DNA and proteins evolved from this RNA-dominated early life, and RNA in cells today is left over from this early time.
While reactions to make RNA from ancient precursors worked on paper, the chemistry didn’t work in the lab. And some scientists thought even RNA molecules were too complex to have spontaneously formed in the primordial soup. Sutherland and his colleagues have shown the reactions are possible.
RNA molecules are formed from three components: a sugar, a base and a phosphate group. In past research, chemists developed each of the components and then tried to put them together to make the complete molecule. “But the components are quite stable, and so they wouldn’t stick together,” Sutherland says. “After 40 years of trying, we decided there had to be a better way of doing this reaction.”
The team took a different approach, starting with a common precursor molecule that had a bit of the sugar and the base. “Basically, we took half a base, added that to half a sugar, added the other piece of base, and so on,” Sutherland says. “The key turned out to be the order that the ingredients are added and the way you put them together — like making a soufflé.”
Another difference is that Sutherland and his team added the phosphate to the mix earlier than in past experiments. Having the phosphate around so early helped the later stages of the reaction happen more quickly and efficiently, the scientists say.
The starting materials and the conditions of the reaction are consistent with models of the geochemistry of an early Earth, the team says.
“But while this is a step forward, it’s not the whole picture,” Ferris points out. “It’s not as simple as putting compounds in a beaker and mixing it up. It’s a series of steps. You still have to stop and purify and then do the next step, and that probably didn’t happen in the ancient world.”
Sutherland and his team can so far make RNA molecules with two different bases, and there are still another two bases to figure out. “It’s related chemistry,” Sutherland says. “That’s how it must have been in the very beginning — a series of fundamental reactions that could make all four types of RNA molecule.”
Once those RNA molecules formed, they would have had to string together to make multiple letters of the code, which could then make proteins. Proteins could then make all the components that make up a cell, and the process would continue from there.
The new findings map out a series of simple, efficient chemical reactions that could have formed molecules of RNA, a close cousin of DNA, from the basic materials available more than 3.85 billion years ago, researchers report online May 13 in
Nature.“This is a very impressive piece of work — a really excellent analysis,” comments chemist James Ferris of the Rensselaer Polytechnic Institute in Troy, N.Y.
The new research lends support to the idea that RNA-based life-forms were the first step toward the evolution of modern life. Called the RNA world hypothesis, the idea was first proposed some 40 years ago. But until now, scientists couldn’t figure out the chemical reactions that created the earliest RNA molecules.
Today, DNA encodes the genetic blueprint for life — excluding some viruses, for those who consider viruses living — and RNA acts as an intermediary in the process, making protein from DNA. But most scientists think it’s unlikely that DNA was the basis of the origin of life, says study coauthor John Sutherland of the University of Manchester in England.
Information-bearing DNA holds the code needed to put proteins together, but at the same time, proteins catalyze the reactions that produce DNA. It’s a chicken-or-egg problem. Scientists don’t think that DNA and proteins could have come about independently — regardless of which came first — and yet still work together in this way.
It’s more plausible that the first life-forms were based on a single molecule that could replicate itself and store genetic information — a molecule such as RNA (SN: 4/7/01, p. 212). RNA world proponents speculate modern DNA and proteins evolved from this RNA-dominated early life, and RNA in cells today is left over from this early time.
While reactions to make RNA from ancient precursors worked on paper, the chemistry didn’t work in the lab. And some scientists thought even RNA molecules were too complex to have spontaneously formed in the primordial soup. Sutherland and his colleagues have shown the reactions are possible.
RNA molecules are formed from three components: a sugar, a base and a phosphate group. In past research, chemists developed each of the components and then tried to put them together to make the complete molecule. “But the components are quite stable, and so they wouldn’t stick together,” Sutherland says. “After 40 years of trying, we decided there had to be a better way of doing this reaction.”
The team took a different approach, starting with a common precursor molecule that had a bit of the sugar and the base. “Basically, we took half a base, added that to half a sugar, added the other piece of base, and so on,” Sutherland says. “The key turned out to be the order that the ingredients are added and the way you put them together — like making a soufflé.”
Another difference is that Sutherland and his team added the phosphate to the mix earlier than in past experiments. Having the phosphate around so early helped the later stages of the reaction happen more quickly and efficiently, the scientists say.
The starting materials and the conditions of the reaction are consistent with models of the geochemistry of an early Earth, the team says.
“But while this is a step forward, it’s not the whole picture,” Ferris points out. “It’s not as simple as putting compounds in a beaker and mixing it up. It’s a series of steps. You still have to stop and purify and then do the next step, and that probably didn’t happen in the ancient world.”
Sutherland and his team can so far make RNA molecules with two different bases, and there are still another two bases to figure out. “It’s related chemistry,” Sutherland says. “That’s how it must have been in the very beginning — a series of fundamental reactions that could make all four types of RNA molecule.”
Once those RNA molecules formed, they would have had to string together to make multiple letters of the code, which could then make proteins. Proteins could then make all the components that make up a cell, and the process would continue from there.
Saturday, April 25, 2009
Researchers Reveal Complete Genetic Sequence of Cow
By Jessica Berman, Washington, 24 April, 2009
An international consortium of researchers has completed mapping the genetic blueprint of the domestic cow, a source of nutrition and livelihood for billions of people around the world.
Scientists say the landmark accomplishment will lead to better food production and improvements in human medicine.The completed bovine genome map is the first full sequencing of a mammalian livestock species. It provides new insight into what makes a cow a cow and identifies important genetic traits that distinguish it from humans and other mammals.
The map, published Friday in the journal Science, is the fruit of a six-year international research effort called the Bovine Genome Sequencing and Analysis Project. The consortium of 300 international scientists mapped the nearly 22,000 genes, or hereditary building blocks, of a Hereford cow - a beef-producing ruminant in wide use around the world.
Scientists compared the cow genome to that of seven other mammals - including the human, dog, rat, mouse, opossum and platypus - and found they share a core set of more than 14,000 genes.
Humans share 80 percent of their genetic sequence with cows, according to the scientists, who say we're more closely related to bovines than to rats and mice.
Researcher Kim Worley at the Baylor College of Medicine in Houston, Texas, which spearheaded the research, says the completed map of the cow genome has implications for laboratory research into new drugs.
"What that means is that when we want to study something that's a human protein we might get better information by studying it in cattle than in mice and rats," Worley said.
Jane Peterson of the Human Genome Project at the US National Institutes of Health, which helped fund the consortium's research, says the cow has been a model for studying human hormone disorders. She says having the entire gene sequence available for study makes the cow a more useful research tool.
"Bovine insulin, for example, was used to find the composition of insulin. And it's also been a model for studying many of the endocrine diseases and the conditions in female cows that are directly related to human[s]," she said.
Cracking the bovine genetic code will also make it a lot simpler and cheaper for cattle breeders to enhance the desirable traits in cattle to produce higher-quality milk and meat, according to geneticist Curt Van Tassell, with the U.S. Department of Agriculture in Beltsville, Maryland.
Van Tassel led a team comparing the bovine sequence in the Hereford cow to six other breeds of cattle, studying important variations, and focusing on the special genes governing cattle reproduction, digestion, lactation and disease resistance.
He says breeders will no longer have to wait years for a bull to produce offspring to learn whether they have desirable genes.
"Specifically what we're able to do is generate a genetic value for a bull the day he's born essentially ... that replaces a process that took six to seven years and $25,000 to $50,000 by collecting performance data on daughters," he said.
A commentary in Science magazine hails the landmark genetics work, predicting that the bovine genetic roadmap may lead to many other important spin-offs.
Wednesday, April 15, 2009
bel302
Prof Narang has asked us to submit the assignment by monday.
The chapter is available at scoops.
Minor 2 copies r checked so contact Prof Gomes. He will show d copies in a day or 2
The chapter is available at scoops.
Minor 2 copies r checked so contact Prof Gomes. He will show d copies in a day or 2
Wednesday, April 8, 2009
Open House
Mail by Dr. D Sundar :
Dear All,
As you may be aware, the IIT-D 'Open House' is scheduled for April 18
(saturday). I would be coordinating the activities for our Department and
would like to have some of you as Activity Heads/Volunteers. It is a day
long affair from 9-5 pm.
Please pass on this message to your other batchmates and seniors/juniors
who may be interested. I look forward to active partcipation from your
side.
Regards,
-Sundar
Dear All,
As you may be aware, the IIT-D 'Open House' is scheduled for April 18
(saturday). I would be coordinating the activities for our Department and
would like to have some of you as Activity Heads/Volunteers. It is a day
long affair from 9-5 pm.
Please pass on this message to your other batchmates and seniors/juniors
who may be interested. I look forward to active partcipation from your
side.
Regards,
-Sundar
Monday, April 6, 2009
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