Originally created 01/16/97

Capsules - short takes on health and science

Bacteria get the worm

Anyone who has trouble getting up in the morning will be impressed by a bacteria known as "Synechococcus PCC 7942."

Even though these tiny organisms divide in half several times a day, they still manage to keep their daily biological rhythms in sync, a new study suggests.

Almost all organisms are known to have daily, or circadian, rhythms. And for most organisms - people, fruit flies, and others included - the cells that maintain those rhythms are long-lasting. But because the bacteria can divide every five to six hours, any individual cell might not even last long enough to experience one cycle of daily rhythms.

Even though the bacteria themselves may be fleeting, their rhythms apparently persist, say researchers from Texas A&M University in College Station, Vanderbilt University in Nashville, Tenn., and Nagoya University in Japan.

Writing in the latest issue of the journal Science, the researchers found that a group of dividing bacteria maintains circadian rhythms.

The scientists monitored the rhythms by measuring the activity of a gene introduced into the bacteria. Even though the bacteria were dividing several times a day, the gene activity waxed and waned in a 24-hour cycle.

Stellar smashups

In 1994, astronomers were calling it the chance of a lifetime - watching the shattered comet known as Shoemaker-Levy 9 crash into Jupiter.

Now Japanese astronomers say the collision may not have been the first planetary smash-up ever witnessed by Earthbound scientists.

Historical records recently unearthed in France indicate that the astronomer Jean-Dominique Cassini may have seen the traces of a similar smash in 1690. In December that year, Cassini observed a dark spot that appeared on the surface of Jupiter - very similar in size and shape to the marks left by the 1994 comet collision.

Scientists have searched for old records of impacts, but none ever held up under scrutiny. However, according to the Japanese amateur astronomers who discovered the new record, Cassini's observations are detailed enough to nail the mark as an impact.

Cassini watched a dark spot appear abruptly on Jupiter's surface, then stretch out and break apart as the violent jovian winds smeared it out. Cassini recorded the changes over 18 days - a time period that establishes it as a bona fide impact mark, according to the researchers. The work will be published in an upcoming issue of the Publications of the Astronomical Society of Japan.

Space may be spaced out nicely

A new report suggests that clusters of galaxies are scattered at regular intervals throughout the universe. If confirmed, this work implies that matter is distributed much more regularly through the universe than scientists had thought.

The large-scale structure of the universe says a lot about what happened during and just after the big bang, when the universe was in its birth throes and infancy.

A team of astronomers led by Jaan Einasto of the Tartu Observatory in Toravere, Estonia, discovered the spacing by gathering information on where galaxies lay in all directions from Earth. They found a regular patterning, with galaxy clusters situated every two billion trillion miles or so.

The distribution is something like a huge, three-dimensional chessboard, the scientists wrote last week in Nature.

Surfers, take note

A new method for studying the ocean, using infrared cameras, may help scientists better understand what happens when a wave breaks.

The details of breaking waves are of interest not only to those people who try to ride them. When a storm approaches, forecasters need to be able to predict how choppy the water will get. And researchers studying global climate change hope to understand the subtle interface between the ocean and the atmosphere to get the most accurate models.

Now Andrew Jessup, an oceanographer at the University of Washington in Seattle, and his colleagues have developed a method for imaging waves as they break. The scientists described their work in a recent issue of the journal Nature.

The technique consists of taking infrared pictures of the skin layer of the ocean, the uppermost millimeter or so. The infrared imaging, which can detect changes in temperature, is able to measure the difference between the slightly cooler skin layer and the warmer water below.

When a wave breaks, it churns up the skin layer and leaves behind a patch of warmer water. By using the infrared cameras to detect the temperature of the wake, Dr. Jessup's team has been able to directly measure the area of that wake.

Theory about hot water may be flawed

When the weather gets rough, most people want to hunker down with a cup of something hot to drink and wait out the storm.

Scientists had believed the same was true of animals trying to survive millions of years ago. As mass extinction wiped out critters on Earth's surface, certain marine animals may have huddled at the bottom of the ocean floor and weathered the storm of extinction.

Biologists had thus thought that the tubeworms, mollusks and other creatures living at hot-water vents on the sea floor might just be descendants of animals that were lucky enough to make it through the "storm."

Now, a new study suggests instead that there's little relationship between ancient and modern creatures thriving at these hotwater vents.

Crispin Little of the Natural History Museum in London and colleagues recently studied a group of fossils from an ancient sea floor vent. Geologic forces have pushed the fossil deposit onto land, where it now lies exposed in the southern Ural mountains of Russia.

The researchers discovered that the 400-million-year-old fossils are quite different from the critters living today at vents on the sea floor. This suggests that somehow different animal groups have moved in to inhabit the vents over time. The scientists reported their work last week in Nature.


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