theoretically...

More news about prions, the putative cause of BSE ("mad cow disease") and the fatal human illness Creutzfeldt-Jakob Disease. Two weeks ago we reported a Science paper which seemed to contradict the idea that the PrP protein could on its own cause this class of diseases, by "recruiting" normal proteins to take on an abnormal shape. In the past week, evidence in favour of prion theory has come thick and fast. A paper in Science records how a team in Russia showed prion recruitment occurring in yeast, which has previously been known to display prion behaviour. And Cell has a series of papers detailing prion behaviour involving proteins alone. The "slow virus" hypothesis may find it hard to catch up.

Clouds could have a greater impact on global warming than industrial gases. Higher temperatures worldwide are due to warmer nights, some researchers say, when clouds act like a blanket to keep the heat in. The claim follows comparisons of the cloudier, less-industrialised southern hemisphere with the north.

We don't store memories about daily events in the same way as things we learn, it seems. In a study of three children with damage to the part of the brain called the hippocampus, researchers found that although the children had no memory of what they had for lunch that day, they still gained almost average marks in school tests - suggesting that their learning ability was unaffected. The hippocampus is a curved arm of grey matter that lies along either side of the brain. The researchers said that the brain must organise different kinds of memories in different ways. The records of daily events, probably reached through the hippocampus, are kept separate from those of a life-time's learning. The work was reported in Science.

Gene patenting a good thing? The University of California is suing the biotech company Genentech, claiming it is infringing the university's patent on recombinant DNA techniques in making synthetic human growth hormone. An early hearing was held last Friday on a parallel suit brought by the university.