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26 February 2011 | NewScientist | 15 THERE’S a skeleton in the closet of male fertility: a hormone produced by bone may play a key role in maintaining testosterone levels. Gerard Karsenty at Columbia University in New York City and his colleagues applied osteocalcin – a hormone produced by bone cells called osteoblasts – to cultures of cells taken from either the testes or the ovaries of mice. They found that testis cells treated with osteocalcin increased production of the male sex hormone testosterone threefold. The ovary cells, however, showed no change in the amount of the hormones progesterone and oestradiol they produced. To find out if this might affect fertility, the team knocked out the gene for osteocalcin in some mice. Male modified mice had significantly smaller testes and Seed betrays secret of germination A SURPRISE discovery about how seeds germinate could boost the development of drought and flood-resistant crops. How seeds absorb water before sprouting has long been queried; the proteins that help create water channels in the cell membranes of mature roots and shoots are absent in germinating seeds. Now Lorenzo Frigerio’s team at the University of Warwick in Coventry, UK, has the answer. They studied the genes expressed as thale cress (Arabidopsis thaliana) germinated and found that growth of water channels on the surface of seed cells is controlled by the same genes that create channels deep within the cell, around water-filled chambers called vacuoles (Molecular Plant, DOI: 10.1093/mp/ssq051). The “unexpected finding” gives us a genetic target to manipulate to improve germination in extreme conditions, says Frigerio. Small shocks may warn that a big quake is on the way ADVANCE warning is the ultimate prize for earthquake studies. Now we have tantalising evidence that it may be possible to build a system to warn of some large quakes in the minutes before they strike. Michel Bouchon at the University of Grenoble, France, and his team studied seismograms recorded before the 1999 Izmit earthquake in Turkey, which killed some 17,000 people. In one recording, they saw five small shocks in the 20 minutes immediately before the event. The seismic signatures of the shocks were remarkably similar, although they differed in magnitude – indicating that PIERRE VERDY/AFP/GETTY IMAGES IN BRIEF The bone factor in male infertility lower sperm counts than their normal counterparts, and when the group bred them with normal females, they found that the litter size was around half normal (Cell, DOI: 10.1016/j.cell.2011.02.004). Karsenty is stumped by the results. “Don’t ask me why it only affects males.” He thinks the bone hormone might also boost fertility in men, as many hormones have been found to have the same effects in both mice and humans. they had originated from the same point below ground. Further analysis confirmed that this point was within a few hundred metres of the focus of the Izmit quake itself, suggesting that the quake and the shocks were linked. The team examined the seismograms for other instances of the shock signature, and identified a total of 40 shocks in the 45 minutes before the Izmit quake. The fact that the shocks preceding the quake became progressively stronger in an identifiable way is an “encouraging” sign that early warning systems can work, says Bouchon (Science, DOI: 10.1126/science.1197341). However, an earlier analysis of the 2004 Parkfield earthquake on the San Andreas fault in California found no evidence of foreshocks, suggesting that such a system will not be universally useful. SOMETIMES pure carbon can turn to jelly. That’s what Patrick Royall at the University of Bristol, UK, found when he simulated cooling the carbon cages called buckyballs. The simulation heated the balls to over 2000 °C and cooled them in less than a billionth of a second. This caused a loosely connected solid network to emerge that behaved like a wobbly gel (arxiv. org/abs/1102.2959). Conventional gels consist of small liquid molecules trapped in a network of larger solid molecules. This is the first example of a gel made of just a solid network, Royall says. The experiment is currently not feasible in practice, but since we now know that a buckyball gel is a possibility, Royall suggests trying to make it in other ways. When buckyballs turn to jelly
