Images Dated 14th August 2002

Cone shell harpoon, SEM

Cone shell harpoon. Coloured scanning electron micrograph (SEM) of the venomous harpoon of a cone shell (Conus sp.), a type of marine snail. The cone shell is a predator that fires this harpoon into its prey, usually a fish or a worm. The venom paralyses the victim, allowing the snail to devour it. The venom is highly toxic, and several human deaths have been recorded. The venom contains proteins called conotoxins, which contain the amino acid Gla (gamma-carboxyglutamic acid). This is involved in the blood clotting process in humans. Study of the snail's biochemistry could lead to new drugs to treat clotting disorders such as haemophilia. Magnification unknown

© VOLKER STEGER/SCIENCE PHOTO LIBRARY

Valium molecule

Diazepam. Computer graphic of a molecule of diaze- pam, also known commercially as valium, a tranqu- illiser drug. The molecule's atoms are colour- coded: carbon (C) is blue, hydrogen (H) is white, chlorine (Cl) is green, nitrogen (N) is turquoise and oxygen (O) is red. Diazepam's chemical formula is C16H13ClN2O. Diazepam, a type of benzodiaze- pine, is a minor tranquilliser with anti-convulsant properties used in the treatment of anxiety and as a hypnotic. It acts centrally on the brain's limbic system. It may cause loss of muscle coordination (ataxia), involuntary movements of the eyes (nystagmus) and sedation. It may cause dependence in users, even in therapeutic doses

© LAGUNA DESIGN/SCIENCE PHOTO LIBRARY