sperm seek the heat

Posted on February 11, 2003 by agnieszka

Sperm cells act like heat-seeking missiles when it comes to locating an unfertilized egg, according to a paper published in the February Nature Medicine. The egg tends to lie in a spot around 2 degrees Celsius warmer than the place where sperm begin their final journey through the female genital tract. Sperm can sense this temperature difference and use it to navigate their way, reports Michael Eisenbach of the Weizmann Institute in Israel. Once in the correct vicinity, the sperm are able to follow chemical attractants released by the egg. Eisenbach tested rabbit and human sperm in a chamber built to simulate a fallopian’s tube temperature gradient, and some of the sperm exhibited a clear preference for swimming toward the warmer area. Eisenbach’s experiments also indicated that only the small percentage of sperm that are fully mature — the ones most likely to actually penetrate the egg — can sense both the temperature gradient and the chemical signals needed to reach the egg.

This news brief appeared in the Random Data column of the Boston Globe’s Health/Science section on 2/11/2003.
Posted in boston globe, news briefs | Comments Off on sperm seek the heat

supersensitive sharks

Posted on February 11, 2003 by agnieszka

As if it’s not scary enough that sharks can smell a drop of blood in an Olympic-sized swimming pool, or that they can sense the electric field given off by a hidden prey’s heartbeat; it seems they can also detect temperature changes of a thousandth of a degree Celsius in seawater, according to a study reported in the Jan. 30 Nature. Sharks have gel-filled canals that connect skin pores to electrosensory organs called ampullae of Lorenzini. Brandon R. Brown, a physicist at the University of San Francisco, analyzed samples of this clear, protein-based gel that were taken from black-tip and white sharks. He found that temperature changes as small as .001 degree in the gel would induce a voltage large enough for the animal to detect. Brown thinks sharks evolved such a sensitive thermometer to help them locate thermal fronts in the ocean, areas where cold and warm water mix, and where many of their quarry feed.

This news brief appeared in the Random Data column of the Boston Globe’s Health/Science section on 2/11/2003.
Posted in boston globe, news briefs | Comments Off on supersensitive sharks

new in print: “from conception to birth” delivers marvels

Posted on February 4, 2003 by agnieszka

Sometimes dazzling, sometimes startling, sometimes disturbing, From Conception to Birth: A Life Unfolds, is the visual diary of a human embryo, following its growth from a single cell to a newborn infant. We are witness to images never before seen with such beauty and clarity — from the beating heart of a 28-day-old, grain-of-rice-sized embryo, to the step-by-step development of the lungs, the nervous system, the eyes, the ears, the teeth, the toes, even the toenails. Everything is shown in graphic, breathtaking, color-drenched detail. A pea-sized embryo is enlarged to fill an over-sized page: Inside and out, its tiny limbs and organs are a delicate marvel of intricacy. Some of the images of the embryo’s early development may make it seem more alien than human, with its flipper-like limb buds and spiral tail (which starts to disappear at 36 days). Other visuals evoke the classic glowing, floating baby-in-space imagery of Stanley Kubrick’s 2001: A Space Odyssey. Continue reading →

Posted in boston globe, reviews | Comments Off on new in print: “from conception to birth” delivers marvels

stone age brits got milk

Posted on February 4, 2003 by agnieszka

Six thousand years ago, neolithic Brits might have enjoyed sips of milk with their steaming haunches of meat. Researchers from England’s University of Bristol report in the Proceedings of the National Academy of Sciences that they have discovered milk-fat residue on 6000-year-old pottery fragments. It is the earliest direct evidence of dairy farming ever found. Until now, it has been difficult to tell meat fat from milk fat. The breakthrough occurred when the researchers discovered that milk fats contain different ratios of the stable isotopes of carbon (carbon-12 and carbon-13) compared to meat fat. While the chemical analysis definitely proves the existence of dairy fat, the researchers don’t yet know how the milk was used. Considering milk’s short shelf life, it’s probable the ancient Britons were making and eating butter, cheese, or yogurt.

This news brief appeared in the Random Data column of the Boston Globe’s Health/Science section on 2/04/2003.
Posted in boston globe, news briefs | Comments Off on stone age brits got milk

groundhogs: checking out ladies, not weather

Posted on February 4, 2003 by agnieszka

Forget the shadow, male groundhogs are looking for love when they emerge from their burrows in early February. Stamatis Zervanos, a biologist at Penn State Berks-Lehigh Valley College, studied 32 free-ranging groundhogs over four hibernation seasons. He found that male groundhogs often visit a few female burrows during their brief period of emergence before returning to their own burrows for the last part of their winter’s sleep. The females, on the other hand, tended to stay close to their burrows. Zervanos thinks the males are using these early excursions as an opportunity to establish their territories and to see which females will be available in preparation for groundhog-mating season, which officially begins in early March.

This news brief appeared in the Random Data column of the Boston Globe’s Health/Science section on 2/04/2003.
Posted in boston globe, news briefs | Comments Off on groundhogs: checking out ladies, not weather

teleportation passes another milestone

Posted on February 4, 2003 by agnieszka

It’s not “Beam me up, Scotty,” just yet, but teleportation has taken another step forward. Scientists from the University of Geneva in Switzerland and the University of Aarhus in Denmark have taken particles of light, destroyed them, and reconstituted them more than a mile away. Previous experiments teleported light particles about 3 feet. Teleportation relies on a strange property of quantum physics called entanglement. When two particles are entangled, whatever happens to one instantly happens to the other, no matter the distance between them. To teleport a particle, however, is not like sending a fax: The first particle’s information is destroyed while it is being reconstituted as an identical particle at another location. This kind of teleportation is still restricted to particles of light, and in the experiment, reported in last week’s Nature, only about one in a thousand were teleported successfully. Considering that humans are made up of trillions and trillions of atoms, it’s unlikely that people will be beamed any time soon.

This news brief appeared in the Random Data column of the Boston Globe’s Health/Science section on 2/04/2003.
Posted in boston globe, news briefs | Comments Off on teleportation passes another milestone

new on television: crikey! another coldblooded reptile show

Posted on January 28, 2003 by agnieszka

Do you like seeing a crocodile chomp down on a struggling, mewling gazelle? How about on a struggling, bleating wildebeest? Or perhaps you want to see the softer side of these ferocious predators, with mother crocs carefully ferrying babies in their toothy maws? Maybe you just like listening to biologists with Australian accents? I think I have the show for you. Continue reading →

Posted in boston globe, reviews | Comments Off on new on television: crikey! another coldblooded reptile show

duck, duck, quail?

Posted on January 28, 2003 by agnieszka

In what would at first glance appear to be a completely useless experiment, researchers have created a duck-billed quail and a quail-billed duck. Jill Helms and Richard Schneider of the University of California at San Francisco successfully transplanted neural crest cells, which in birds give rise to beaks, from one bird embryo to another. When the embryos were examined days later, the quail was growing the wide, flat bill of a duck, and the duck was growing the little, pointy beak of a quail. Not only did the transplanted cells create the mismatched bills, but they also modified some of the surrounding cells, influencing their genes and rate of development. Neural crest cells develop into many of the bones of the face and skull in vertebrates. The researchers, who reported their findings in last week’s issue of Science, hope that by understanding how beaks develop, they can shed light on how deformities such as cleft palates and other facial birth defects occur in humans.

This news brief appeared in the Random Data column of the Boston Globe’s Health/Science section on 1/28/2003.
Posted in boston globe, news briefs | Comments Off on duck, duck, quail?

hamburger from space

Posted on January 28, 2003 by agnieszka

When was the last time a Hubble Space Telescope image made you hungry? Located some 6,500 light-years away in the constellation Sagittarius, the celestial object called Gomez’s Hamburger (in honor of its discoverer, Arturo Gomez) is a sunlike star nearing the end of its life. The “patty” is actually a thick disc of dust surrounding and hiding a central star, and starlight reflecting off the ejected dust forms the “bun.”

This news brief appeared in the Random Data column of the Boston Globe’s Health/Science section on 1/28/2003.
Posted in boston globe, news briefs | Comments Off on hamburger from space

walking stick, flying stick

Posted on January 28, 2003 by agnieszka

Stick insects, famed for their extraordinary ability to look just like, well, sticks, are now famous for something altogether different. They are the first creatures known to have re-evolved the ability to fly. Michael Whiting and his colleagues at Brigham Young University in Provo, Utah, reported in the Jan. 16 issue of Nature that the insects have lost and re-evolved wings at least four times over the past 300 million years. That’s not supposed to happen: A key evolutionary concept is that once a complex anatomical feature such as a wing or a leg is lost, it can’t come back. The surprising finding comes from DNA data from 37 stick-insect species that was collected as researchers were constructing the creatures’ family tree. Whiting suspects that re-evolution may have taken place in cockroaches and other insects as well. The theory of evolution may undergo a revolution if re-evolution does indeed exist.

This news brief appeared in the Random Data column of the Boston Globe’s Health/Science section on 1/28/2003.
Posted in boston globe, news briefs | Comments Off on walking stick, flying stick