Sperm less potent as men get older
Many women complain that they have decreasing fertility to look forward to as they age, while men keep their reproductive capabilities intact. But it turns out that aging men may have their own biological clock.
As they collect years, their sperm collects DNA damage and abnormalities that can contribute to infertility and unsuccessful pregnancies, according to new research at Lawrence Livermore National Laboratory in Livermore, Calif., and at the University of California, Berkeley.
The team previously found that as men age, their sperm slowly loses its pep and ability to swim a straight line. The new study, which appeared online this week in the Proceedings of the National Academy of Sciences, added more bad news for men.
In addition to making it harder to get a partner pregnant, reduced sperm mobility often goes hand in hand with DNA damage that increases the risk of miscarriage and children with genetic problems.
Multiple sclerosis drug returns
A multiple sclerosis drug pulled from the market last year because of a rare but life-threatening side effect will return under a restricted distribution program, officials said this week.
The Food and Drug Administration said it will let Biogen Idec Inc. and Elan Corp. resume selling Tysabri under a requirement that doctors, pharmacies and patients register with a program designed to ensure the safe use of the drug.
Tysabri received FDA approval in November 2004. It was withdrawn voluntarily in February 2005 after two patients in clinical trials died of a rare brain infection.
Australian mounds fossils of oldest life
Odd-shaped mounds of dirt in Australia turn out to be fossils of the oldest life on Earth, created by billions of microbes more than 3 billion years ago, scientists say in a new report. And these mounds are exactly the type of life astrobiologists are looking for on Mars and elsewhere.
A study published yesterday in the journal Nature gives the strongest evidence yet that the mounds dotting a large swath of western Australia are Earth's oldest fossils. The theory is that these are not merely dirt piles that formed randomly into odd shapes, but that ancient microbes burrowed in and built them.
"This is the pointy end of the fossil record; this is the first really compelling record," said study lead author Abigail Allwood, a researcher at the Australian Centre for Astrobiology. "It's an ancestor of life. If you think that all life arose on this one planet, perhaps this is where it started."
The mounds are called stromatolites and have been studied for a long time, but the big question has been whether they were once teeming with life. In a similar situation 10 years ago, scientists at NASA claimed they found evidence of fossilized microbial life in a Martian meteorite. Those claims have been sharply disputed.
Figs earliest known domesticated crop
Gourmets savoring their roasted figs with goat cheese may not realize it, but they are tasting history. Archaeologists report finding evidence that ancient people grew fig trees about 11,400 years ago, making the fruit the earliest domesticated crop.
The find dates use of figs about 1,000 years before the first evidence that crops such as wheat, barley and legumes were being cultivated in the Middle East.
Remains of the ancient fruits were found at Gilgal I, a village site in the Jordan Valley north of ancient Jericho, Ofer Bar-Yosef of Harvard University and Mordechai E. Kislev and Anat Hartmann of Bar-Ilan University reported in the journal Science. Gilgal was abandoned more than 11,000 years ago. The fig remains they found appeared to have been dried for human consumption, the researchers said. Other food remains found there included acorns and wild oats and wild barley, but no other domesticated crops.
Colon supports vital ecosystem
Deep inside us is a vast ecosystem, as complex as the soil or the oceans, that helps us digest food and contributes to our health and well-being. Now scientists from the Institute for Genomic Research in Rockville have carefully cataloged the teeming life inside the human colon for the first time.
Among the findings, published in the journal Science: The thriving community contains as many as 100 trillion microbes, representing more than 1,000 species, and includes more than 60,000 distinct genes - twice as many as in the human genome. The researchers also found, among other things, that the gut-dwelling microbes synthesize vitamins and break down sugars that humans could not otherwise digest.
They hope, down the road, that monitoring or altering genes inside the colon will provide early signs of illness, new ways to optimize nutrition, and perhaps even new ways to predict how much of an oral medication can be absorbed.
Los Angeles Times
Clusters of galaxies give clues to past
Astronomers have used large clusters of galaxies as "cosmic telescopes" to discover what appear to be infant galaxies from the first billion years after the beginning of the universe.
The technique may well have given astronomers their best view into the early universe, more than 12 billion years ago, said Holland Ford, a professor of astronomy at the Johns Hopkins University and head of the Hubble Space Telescope's Advanced Camera for Surveys Science Team.
Ford and an international team of scientists announced the results this week at the American Astronomical Society meeting in Calgary, Alberta. Ford said the group's spectroscopic observations were made possible by gravitational "lensing," the bending of light caused by gravity's warping of space in the presence of such large objects as clusters of galaxies.