14 | NewScientist | 12 January 2013

CORRECTING abnormal signals in the womb may help prevent repeated miscarriages.

After fertilisation, an embryo must embed itself within the inner layer of the uterus – the endometrium. The endometrium is only receptive to an embryo for four days in each menstrual cycle, ensuring that implantation occurs at the right time. By analysing human endometrial

cells implanted in mice, Jan Brosens at the University of Warwick, UK, and his colleagues discovered that the four-day window is regulated by a molecule called interleukin-33. IL-33 controls signals to genes that make the endometrium sticky enough for implantation. These signals are switched off after four days, when the endometrium starts to prepare for the next

Mars’s crust was stuffed with water

A ROASTED rock bought in Morocco has added spice to Mars’s past. Charred by its fall to Earth, this chunk of the Red Planet is loaded with water, suggesting that we may need to revise our picture of when Mars dried out.

Other Mars meteorites have had unusual oxygen isotopes that gave away their origin. But their minerals did not match surface rocks studied by Mars rovers and orbiters, hinting the meteorites came from deeper down.

The new meteorite, dubbed Northwest Africa 7034, closely resembles rocks that rovers have studied and is likely to be the first piece of Martian crust found on Earth, says Carl Agee of the University of New Mexico in Albuquerque (Science, doi.org/j5b). The rock, 2.1 billion years old, also holds many more water-bearing minerals than other finds, suggesting Mars’s surface stayed moist longer than we thought.

Life will find a way, even in the midst of a hurricane

LIFE ahoy! Every hurricane that sweeps through the Gulf of Mexico carries a unique mix of bacteria in its clouds.

Much of our precipitation is likely caused by microbes in clouds. Their surfaces act as “seeds” to attract water and form ice crystals that fall through the cloud as rain or snow. To find out the nature of the bacteria, in 2010 researchers from the Georgia Institute of Technology in Atlanta flew a jetliner through hurricanes Earl and Karl, 10 kilometres above the Earth’s surface.

Twenty per cent of the small particles they collected turned out to be bacteria that could grow in the lab. Many

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Bad timing may cause miscarriage cycle. In mice receiving cells from women who’d had more than one miscarriage, IL-33 signals lasted up to 10 days. Subsequent pregnancies failed in these mice because the embryo implanted when the endometrium could not support it (PLoS One, doi.org/j49).

“This is an important discovery,” says Nicholas Macklon at the University of Southampton, UK. “We now have a potential target to improve the selective function of the endometrium.”

were genetically similar to bacteria the researchers had earlier found in clouds over the US land mass and along the California coast. The similar bacteria could withstand UV radiation at high altitude, and use simple carbon compounds as their sole energy source, suggesting that they had adapted to survive in clouds.

But the bacterial communities in the two hurricanes were very different from one another – probably because the hurricanes began in different places. The team believe that the storms swept up species from the soil and ocean as they moved inland. This mix of bacteria could have increased the amount of rain from the hurricane by providing better “seeds” for the water to form around. The group presented their work at the American Geophysical Union meeting in San Francisco in December.

THE dating game is tough for male Ooencyrtus kuvanae wasps. Not only does each female mate only once, but the eggs of several females all hatch at once, leaving the males in a race to find mates.

To see how male wasps get their girl, a team led by Gerhard Gries of Simon Fraser University in Canada looked at captive insects. One male placed with a group of females would mate with all the unmated females, they found. But when more than one male was present, some males switched to tagging females with pheromones from their antennae.

The tagged females avoided other males, so the males who tagged them ultimately mated more often (Behavioural Processes, doi.org/j5j).

Male wasps win out by tagging females

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