Posted on 11/16/2005 3:40:35 AM PST by snarks_when_bored
* 14:02 15 November 2005
* NewScientist.com news service
* Gaia Vince
A new microscope sensitive enough to track the real-time motion of a single protein, right down to the scale of its individual atoms, has revealed how genes are copied from DNA – a process essential to life.
The novel device allows users to achieve the highest-resolution measurements ever, equivalent to the diameter of a single hydrogen atom, says Steven Block, who designed it with colleagues at Stanford University in California.
Block was able to use the microscope to track a molecule of DNA from an E.coli bacterium, settling a long-standing scientific debate about the precise method in which genetic material is copied for use.
The molecular double-helix of DNA resembles a twisted ladder consisting of two strands connected by “rungs” called bases. The bases, which are known by the abbreviations A, T, G and C, encode genetic information, and the sequence in which they appear “spell out” different genes.
Every time a new protein is made, the genetic information for that protein must first be transcribed from its DNA blueprint. The transcriber, an enzyme called RNA polymerase (RNAP), latches on to the DNA ladder and pulls a small section apart lengthwise. As it works its way down the section of DNA, RNAP copies the sequence of bases and builds a complementary strand of RNA – the first step in a new protein.
“For years, people have known that RNA is made up one base at a time,” Block says. “But that has left open the question of whether the RNAP enzyme actually climbs up the DNA ladder one rung at a time, or does it move instead in chunks – for example, does it add three bases, then jump along and add another three bases.
Light and helium
In order to settle the question, the researchers designed equipment that was able to very accurately monitor the movements of a single DNA molecule.
Block chemically bonded one end of the DNA length to a glass bead. The bead was just 1 micrometre across, a thousand times the length of the DNA molecule and, crucially, a billion times its volume. He then bonded the RNAP enzyme to another bead. Both beads were placed in a watery substrate on a microscope slide.
Using mirrors, he then focused two infrared laser beams down onto each bead. Because the glass bead was in water, there was a refractive (optical density) difference between the glass and water, which caused the laser to bend and focus the light so that Block knew exactly where each bead was.
But in dealing with such small objects, he could not afford any of the normal wobbles in the light that occur when the photons have to pass through different densities of air at differing temperatures. So, he encased the whole microscope in a box containing helium. Helium has a very low refractive index so, even if temperature fluctuations occurred, the effect would be too small to matter.
One by one
The group then manipulated one of the glass beads until the RNAP latched on to a rung on the DNA molecule. As the enzyme moved along the bases, it tugged the glass bead it was bonded too, moving the two beads toward each together. The RNAP jerked along the DNA, pausing between jerks to churn out RNA transcribed bases. It was by precisely measuring the lengths of the jerks that Block determined how many bases it transcribed each time.
“The RNAP climbs the DNA ladder one base pair at a time – that is probably the right answer,” he says.
“It’s a very neat system – amazing to be able see molecular details and work out how DNA is transcribed for the first time,” said Justin Molloy, who has pioneered similar work at the National Institute for Medical Research, London. “It’s pretty incredible. You would never have believed it could be possible 10 years ago.”
Journal reference: Nature (DOI: 10.1038/nature04268)
This is one reason why I think Uncle Fester is more than one person, or has a multiple personality disorder.
Are you positing the designer just as a "Prime Mover"?
"I reckon that places the reality ball firmly in my court, then. Why you feel so obligated to avoid reality is one of those mysteries that science will never solve."
No, it means anything can be *evidence* of your hypothesis. Your *feeling* isn't scientific, it's mystical. You can't even hypothetically imagine a fact that could go against your feeling. Your feeling has absolutely zero practical value. If the world was completely disorganized, you would say it was designed. Why not? Anything could be design according to you. Order, chaos; all the same.
I see you added the qualifier "productively." Certainly a relative qualification. I wonder if Galileo was chided for engaging in such non-productive activities as rolling his balls down inclines and then taking measurements. Science can do good for itself by not imposing unnecessary limitations. Declaring that intelligence is beyond the grasp of science where design is evident is not exactly a productive, let alone scientific, declaration. It smacks of something "philosophical."
"They weren't exactly "warriors for God," but Ghengis Khan and Attila the Hun were very effective in their use of large-scale killing, and they didn't use high-tech weapons to do it. Your appeal to high technology is thus somewhat irrelevant; further, it merely points out something else: people are willing and able do really bad things and always have been.
You are assuming that only high technology weapons are thought by Ichneumon to create high death tolls. This isn't what he was saying. If I understand him correctly, the idea is that high technology makes it much easier to get high death numbers. In a situation where 100 deaths can be caused by swords, 10,000 can be caused by today's weapons. This simply means that the numbers of deaths is inflated by technology.
Yes, people who value others less than their ambition can and will do terrible things. Their belief, or lack of belief in a God is incidental.
I hate to tell you this, but the presence of organized matter is not my *feeling.*
Now there's an image I'm not likely to get out of my mind for a while. As my grandson would say, YUK!
Are you being cruel? ;->
Thanks. I didn't know that. But if the unique place on one DNA strand isn't at one end of the strand, it would seem that the RNA doesn't replicate the entire DNA strand. That must be enough to make a protein. And the entire strand is only replicated during mitosis. Correct?
And positively dangerous for the spread of deadly diseases and ideas.
He was chided, arrested, threatened with torture, and placed under house arrest for the remainder of his life for his researches.
The treatment (in the Name of Religion) of American Indians, particularly in the Southwest and Latin America, isn't very pretty. Of course, the body count is inflated by using a 300 year timeline. (Not to mention the Capitalist Robber Baron rubber manufacturers.)
Hmmm. Appeal to popularity. Again. This should be in PH's Toolkit.
The DNA dependent RNA polymerase doesn't replicate the DNA. It reads the DNA and makes an RNA message that is usually translated on the ribosomes into a protein. Most bacterial chromosomes are circular so they have no
'end". For those DNAs that are linear AFAIK, the ends do not contain information that gets translated.
'
It is not unscientific to begin with a particular world view. I happen to admit mine. Just because God created the heavens and the earth and still sustains them does not mean I have to choke Him out of scientific inquiry. It is a no-brainer that science uncovers intelligent design in every nook and cranny of existence. These are readily apparent signs of His handiwork. Life is a readily apparent sign of His ongoing involvement with His creation.
Science will continue to affirm this truth. Only those blinded by a philosophy of their own will distort the meaning of science in some way as to make mention of the designer wholly "unscientific." So a bunch of people do that. No surprise.
The standards for science are rather simple. Research must provide novel data, or must attempt to replicate data that is not firmly established. Scientific investigation must provide data that supports or is inconsistent with an explanatory hypothesis.
The specific methodologies differ from field to field, but are the result of centuries of invention and testing.
If ID ever develops a methodology or hypothesis, it might become part of science.
The lib tactics belong to people like you who would perpetrate fraud in the name of science, consistently misinterpret and misrepresent evidence, engage in ad-hominem ad nausaeum, all the while claiming to be intellectually superior.
Kindly cite examples of my doing any of that, or retract it.
I have consistently debated you on the evidence. You respond with personal attacks. That is not unexpected, but it is disappointing.
It is not unscientific to begin with a particular world view.
It is unscientific to ignore evidence that doesn't conform to your particular world view, however.
It is unscientific to consider your particular world view evidence in itself.
The second becomes a non-sequitur by dash.
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