microscopy: a new way of seeing inside tissues and cells

Posted on February 24, 2004 by agnieszka

Researchers have developed a powerful new method to peer inside cells and tissues. As reported in this week’s Proceedings of the National Academy of Sciences Early Edition, Stephan Thiberge of Israel’s Weizmann Institute of Science and his colleagues have come up with a way to use the scanning electron microscope, or SEM, on these “wet” biological specimens. Samples to be examined by SEMs, which use focused beams of electrons instead of light to scan the surface of objects, traditionally must be held in a high-vacuum environment. Under these conditions, a sample that holds water, such as a piece of tissue or a cell, is explosively unstable, so it has to be dehydrated, changing its normal appearance. To circumvent this problem, the researchers found a way to protect the fluid-filled sample from the vacuum by using a thin polymer membrane transparent to the electron beam. Using the “wet SEM” technique, the researchers were able to see not only the exterior of a cell, as in a traditional SEM, but its interior structures as well. The researchers believe their method opens opportunities for medical investigations, including tissue biopsies.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 2/24/2004.
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astronomy: supernova puts on stellar light show

Posted on February 24, 2004 by agnieszka

NASA’s Hubble Space Telescope has recorded yet another dramatic image of the universe around us, this time the death throes of a fading supernova. Called SN 1987A, the brightest stellar explosion of modern times was discovered by astronomers 17 years ago. Today the supernova is a million times fainter, but this image captured by Hubble on November 28, 2003 shows it is going out with style. A star goes supernova when it exhausts its fuel supply. Its core collapses, sending out a shock wave that tears the star apart. Now SN 1987A’s shock wave is slamming at a speed of more than a million miles per hour into a ring of gas that the star shed some 20,000 years before the explosion, heating it up and making it glow, producing the “pearls” of light seen here. The pearls will eventually turn into a solid glowing ring as the full force of the wave is absorbed in the next few years. Astronomers hope that the ring will be bright enough to light up the star’s surroundings, giving them more data on how the star ejected material before the blast.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 2/24/2004.
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evolution: understanding dog understanding

Posted on February 17, 2004 by agnieszka

Dogs have an uncanny knack for understanding human gestures — and we may have helped them evolve it. Previous research by Harvard anthropologist Brian Hare demonstrated that domesticated canines interpret human cues such as glances or pointing better than our closest animal relative, the chimpanzee, or their closest dog relative, the wolf. Building off that work, Hare and his colleagues announced last week at the annual meeting of the American Association for the Advancement of Science that ongoing human contact during a breed’s domestication is key for this ability to evolve. Testing the feral New Guinea singing dog, a subspecies that shows signs of being domesticated in the past but has been without significant human contact for at least 6,000 years, the researchers found that the animal could not pick up on human-given signals to locate hidden food that a domesticated dog easily understood. “Our new work provides direct evidence that dogs’ lengthy contact with humans has served as a selection factor, leading to distinct evolutionary changes,” Hare stated in a press release. “This is the first demonstration that humans play an ongoing role in the evolution of canine cognition.”

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 2/17/2004.
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botany: why flowers bloom in the spring, tra-la

Posted on February 17, 2004 by agnieszka

The scientific basis for springtime is now better understood, thanks to a new study from the Max Planck Institute for Plant Breeding in Germany and The Hebrew University of Jerusalem in Israel. Reporting in the Feb. 13 Science, Federico Valverde and his colleagues explain the molecular mechanism by which plants flower in response to light. Conducting experiments on the small, flowering plant, Arabidopsis, they showed how day length and light quality affect Constans, a protein that promotes flowering. The researchers found that light stabilizes the protein, and that, in the dark, the protein is degraded. So, as the hours of daylight increase in the spring, more of the protein is maintained, until enough accumulates to activate the genes that trigger flowering.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 2/17/2004.
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astronomy: oxygen, carbon found on faraway planet

Posted on February 10, 2004 by agnieszka

An international team of astronomers using the Hubble Space Telescope has found the first planet outside our solar system with detectable oxygen and carbon in its atmosphere. But the possibility of extraterrestrial life is pretty slim. Planet HD 209458b (nicknamed Osiris) is a hot Jupiter-like gas giant tightly orbiting a star 150 light-years away. The planet’s upper atmosphere is a fiery 18,000 degrees Fahrenheit. At such extreme temperatures, hydrogen atoms can escape the planet’s gravity at near sonic speeds, dragging heavier oxygen and carbon atoms with them, a phenomenon called “blow off.” It was the oxygen and carbon that the team detected. The combined gravitational fields of the star and planet stretch Osiris’s evaporating atmosphere into an elliptical shape. The discovery is to be reported in an upcoming issue of Astrophysical Journal Letters.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 2/10/2004.
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genetic engineering: microbes make missile fuel and medication

Posted on February 10, 2004 by agnieszka

To help make safer and cheaper rocket fuel, the US military has enlisted some pretty small soldiers — bacteria. Funded by the Office of Naval Research, microbiologist John Frost of Michigan State University and his team reported in a recent issue of the Journal of the American Chemical Society that they have modified the genes of E. coli and Pseudomonas fragi to allow them to manufacture the chemical butanetriol. Butanetriol is used to produce the rocket propellant BTTN, or butanetriol trinitrate, which is used in the Hellfire missile, among others. Navy scientists have been using less-expensive nitroglycerin, which is notoriously unstable, but the researchers hope that the new “bioproduction” method could keep costs down so that the safer butanetriol could begin to replace it in many applications. And butanetriol has more than just military uses: It is also a precursor to two cholesterol-lowering drugs. Stated Frost in a press release, “This is a classic example of dual use for molecules between pharmaceutical and defense applications.”

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 2/10/2004.
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cell biology: salt causes DNA damage in cells

Posted on February 10, 2004 by agnieszka

Natalia Dmitrieva of the National Heart, Lung and Blood Institute and her colleagues have shown that high concentrations of salt can damage DNA and the cellular mechanisms that would otherwise repair it. Writing in the Proceedings of the National Academy of Sciences Online Early Edition this week, the researchers report these results after culturing mouse cells in salt solutions. The cells appeared outwardly normal, but upon closer examination, it was shown that there were gaps in their DNA. The researchers also found that a protein that initiates DNA repair was unable to enter the nucleus of the cell, where the DNA resides. (Once salt concentrations were returned to normal, the protein was able to repair the damaged DNA again.) But was this purely a lab phenomenon? Cells in the kidneys, for example, are exposed to greater amounts of salt than other cells due to their involvement in regulating salt excretion in the body. Sure enough, the researchers found DNA damage and inhibited DNA repair in the kidneys of normal mice as well.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 2/10/2004.
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physics: new find could improve superconductors

Posted on February 3, 2004 by agnieszka

Physicists from the University of Colorado at Boulder recently created a brand-new form of matter — the sixth, after solids, liquids, gases, plasmas and Bose-Einstein condensates — that could lead to more efficient power plants, faster and smaller computers, and even magnetically levitated trains. Reported in last week’s Physical Review Letters, the new type of matter, known as a fermionic condensate, is a crucial first step in the development of superconductors (materials in whichelectricity is transmitted with no loss of energy) that work at room temperature, rather than the minus 216 degrees Fahrenheit now required. “This makes me optimistic that the fundamental physics we learn through fermionic condensates will eventually help others design more practical superconducting materials,” lead researcher Deborah Jin, also of the National Institute of Standards and Technology, stated in a press release.

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 2/03/2004.
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paleontology: fossil found by bus driver “of enormous value”

Posted on February 3, 2004 by agnieszka

The remains of the earliest-known land-living animal have been discovered — not by a famous paleontologist but by Scottish bus driver and amateur fossil hunter Mike Newman. Newman found the tiny fossilized millipede in the Scottish seaside town of Stonehaven and donated it to the National Museums of Scotland. Experts there and from Yale University report in the January issue of the Journal of Paleontology that the primitive breathing holes found on its body and its approximate age of 428 million years make it the oldest air-breathing animal yet found. “This fossil is of enormous scientific value. It demonstrates that air-breathing animals lived on land over 20 million years earlier than we thought, and changes our understanding of the landscape at that time,” study author Lyall Anderson of the National Museums stated in a press release. The new species of millipede, Pneumodesmus newmani, has been named after its discoverer. “Well, that’s pretty cool really,” Newman told the World Today radio program, “because, you know, it’s going to have that name pretty much forever, and it’s just not any old creature; it’s not like a shell or anything like that.”

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 2/03/2004.
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ecology: prehistoric people changed ecosystems

Posted on January 27, 2004 by agnieszka

It’s been commonly assumed that American ecosystems remained pristine until the arrival of European settlers, who, by cutting down forests, introducing foreign species, and polluting the environment, disturbed the indigenous flora and fauna. But prehistoric Native Americans also altered their ecosystems, albeit on a smaller scale, reports a team of Canadian researchers in this week’s Proceedings of the National Academy of Sciences Online Early Edition. Studying a freshwater pond in the Canadian Arctic that was near an abandoned 800-year-old winter settlement built by prehistoric Inuit whale hunters, Marianne Douglas of the University of Toronto and her colleagues found evidence that nutrient-rich whale byproducts leaching into the soil led to the pond having algal blooms, and affected its water quality and chemistry as well. Though the settlement has been deserted for more than 400 years, the human-caused disturbances are still evident today. The authors write: “It is ironic that the High Arctic, generally considered to be the last refuge from local human disturbance, contains the oldest record thus far obtained in the United States or Canada of a human population affecting freshwater ecology.”

This news brief appeared in the Discoveries column of the Boston Globe’s Health/Science section on 1/27/2004.
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