Science: theoretically

Click to follow
The Independent Online
Douglas Adams made it vaguely famous, but the kakapo - the huge, flightless New Zealand parrot, one of the world's most endangered species - seems to be making a modest comeback. Four chicks have hatched this year, making 1997 the most successful breeding season since 1981, said New Scientist. No other chicks have hatched since 1992, but this brings the world kakapo population to 54.

Folding doesn't matter only to followers of the art of origami: it's essential to proteins, too, in that the way in which the chains of amino acids form complex three-dimensional structures affects their function. (The classic example would be the PrP protein, which changes shape in Creutzfeldt-Jakob Disease, or CJD.) It had been thought that "unfolded" chains, consisting solely of a simple chain, could not do anything. But now a team of American scientists has found that certain bacteria, which have a "tail" or flagellum that they use for propulsion, use largely unfolded proteins. Commenting on the work in Nature, Kevin Plaxco and Michael Gro, at the Oxford Centre for Molecular Sciences, suggest there may be an evolutionary reason: if the protein was already folded, the bacteria couldn't pass it through the nanometres-wide entrance to the part of flagellum where it's needed.

How fast do cheetahs really run? A long-standing report that they run at up to 114 kilometres per hour (71mph) was wrong - the wrong distance was measured, the timing was wayward and the arithmetic flawed. But a re-examination of separate timings made in 1965 suggests that they are indeed the fastest land animals over sprint distances. A report in the Journal of Zoology suggests that, when given a running start, they can sustain an average speed of up to 105kph (60mph) over about 100 metres, compared to racehorses (69kph) and greyhounds (58kph). Humans, by comparison, only briefly touch 48kph (30mph) in the Olympic 100 metre sprints.

Reclassification of a fossilised hominoid first found in Uganda in the 1960s suggests it may be the oldest known human/ape ancestor, dating from 10 to 25 million years ago. The work, reported in Science, suggests that while the face and teeth seemed primitive, the vertebrates seemed similar to that of living hominoids, suggesting that the animal had an upright, stiff-backed posture.

Comments