by joe eskenazi
staff writer
Could Homer Simpson’s uncanny ability to survive the many nuclear meltdowns he’s triggered have something to do with his staple food, the doughnut?
If pressed, Israeli scientists might have two answers: 1. Perhaps. And 2. He’s a cartoon.
All joking aside, doughnut-shaped groupings of DNA are the basis of Professor Abraham Minksy’s research. He’s found that the unusual ring patterns account for a rare bacteria’s ability to survive doses of radiation 4,000 times greater than those that would kill a non-animated human being.
The Israeli scientist was one of many in San Francisco last week during the Weizmann Institute of Science’s Bay Area Global Gathering. The lectures were part of an annual showcase for American supporters of the Israeli scientific institute.
Minsky — who, not surprisingly, describes the doughnut-shaped pattern with the more scientifically proper term of “toroid” — painstakingly explained that the DNA’s grouping pattern is far more than aesthetic.
Bombardments of radioactivity tear through DNA like cannon balls through a ship’s hull. Exposure becomes fatal when both strands of the double helix are broken. The resulting loose strands of DNA are more than likely to recombine in the wrong sequence, which either kills the cell or, worse yet, creates a malignant cell that can go on to kill the entire organism.
Yet when blasts of radiation hit the Deinococcus Radiodurans bacteria with its doughnut-shaped DNA, something different happens. Yes, the radiation blows apart the bacteria’s DNA, but, unlike virtually any other creature on earth, the DNA fragments aren’t scattered far and wide but tightly contained, with the toroid grouping acting like a microscopic corral. With all the fragments centralized in one small spot, the bacteria is more than 100,000 times more efficient at reassembling its DNA than, say, you are.
Minsky noted that the U.S. Army is one of his major funders.
“Why should the Army of the United States waste money on the sequencing of bacteria? One answer is that wasting money is something armies are very good at,” he said, eliciting laughs from the more than 100 conferencegoers taking in his lecture at the Four Seasons Hotel.
“Usually, they waste money on creating new machines to kill and destroy. But any army would be happy to have a drug that makes its soldiers immune to radioactivity. And that’s something I can sympathize with, having Iran on our back door.”
Minsky’s work could also lead to specialized bacteria that can be used to treat nuclear waste, the development of methods of killing impossibly hearty pathogens such as anthrax and a greater understanding of why individual bacteria and bacteria colonies often resist even the latest antibiotics.
Minsky’s Weizmann colleague, Professor Michael Walker, caught the attention of the crowd by opening up his lecture with a projection of a green-skinned, fiddle-playing Chassid perched on a roof.
Just as the figure in the Marc Chagall painting needed an acute sense of balance to keep from tumbling off the roof, human beings need to maintain a precise chemical balance to be able to handle day-to-day situations, he said.
The Scottish-born Walker claimed diabetes has reached epidemic proportions in both the United States and the world, and he utilized a map of America to bolster his point. Whereas in 1990 only six states reported an incidence of diabetes at 6 percent or more, by 2000 that number had swelled to 42 states. Diabetes-related issues cost U.S. taxpayers a whopping $180 billion a year, he noted.
To blame for the massive swelling of the ranks of American diabetes patients is Americans’ massive swelling. Walker let his props do the talking — his next graphic was a close-up photograph of an obese man’s stomach straining a button-up shirt to the breaking point.
“Obesity is driving this epidemic. That’s one of the few issues in this field that scientists all agree on,” he said.
“What we don’t agree on is what the molecular connection is between obesity and diabetes.”
Walker believes he’s on to something, though.
While fat is demonized by diet gurus across the globe, Walker notes that, without fat, our cave-dwelling ancestors would never have made it out of the Ice Age. In fact, he’s engineered mice that have no fat whatsoever, and they die almost immediately if forced to fast even a little.
Yet the fat that saved the cave dwellers is dooming the Big Mac generation. Walker mimicked a junk food diet in two groups of mice, one with elevated levels of a protein receptor he called GPR40 and one with no GPR40 at all.
Mice with elevated levels of the receptors had problems generating insulin when bombarded with high levels of glucose — in other words, they were diabetic. Mice without the receptor demonstrated no such problem, and had no accumulations of fat in their livers, as diabetics would.
The discovery could lead to drugs suppressing the body’s GPR40 and, possibly, an actual cure for adult-onset diabetes.
The final lecture of the morning was delivered by Professor David Harel, who aims to create computer models of biological systems that are so accurate that biologists won’t be able to tell which is real and which is Memorex, so to speak.
The British-born professor showed the crowd a computer model his lab has created of T-Cell development in the thymus gland. A hugely complicated series of data and probability factors served as the engine creating a graphic rendition of cell birth, growth and death resembling a 1980s Atari X’s and O’s football game in rapidly sped-up motion.
“People ask me, ‘Is it just a pretty movie?’ But it is not a movie at all. It is an interactive model,” he pointed out.
“We have discovered some interesting things about the effects of competition in the formation of this organ. If you change some parameters about how willing [the cells] are to elbow each other, it affects organ development in different ways.”
Multiple predictions generated by Harel’s computer model have been independently confirmed in laboratory experiments.
In the end, Harel would like to model whole organisms or even groups of organisms — a herd of elephants, perhaps.
“You’re done when the biologists can’t tell the difference between the model and the real behavior,” he said.
CopyrightJ, the Jewish news weekly of Northern California