A SMALL group of proteins, collectively known as heat shock proteins (HSP), have been the cause for considerable excitement lately. These proteins had initially attracted attention because they seemed to be generated in an extraordinarily large variety of organisms - ranging from bacteria to humans -in response to an increase in environmental temperature above their normal levels.

Heat shock causes a significant rise in the HSP level and a simultaneous decrease in the level of most other proteins that are otherwise created in substantial amounts. The genes that encode HSPS can respond to temperature, but they are not thermometers: if you put a fly HSP gene in a mammalian cell, it creates fly HSP when the temperature is raised, but does so only at the temperature characteristic for the mammal.

Subsequent work has shown that HSPS are part of a non -specific defensive response of the system -not just to heat shock, but to a large number of stressful situations including starvation or poisoning. D N Deobagkar and colleagues at the department of zoology, University of Pune, Maharashtra, have reached an interesting conclusion with regard to HSP synthesis in mosquitoes. The observations could have disturbing implications for pest control. The report highlighting the results of their research is due to appear soon in the British Journal of Medical and Veterinary Entomology.

These scientists studied two mosquito species, the Anopheles stephensi and the Aedes aegypty. Larvae of both species die within about two hours if they are exposed to a temperature of 43