Chemical world This week
In Brief Research on two fronts has boosted the fortunes of juvenile hormone in the search for substitutes for DDT and other persistent pesticides 9
A rare baryon and unusual fission of a fermium isotope further broaden understanding of nuclear and particle physics 10
An aluminum alloy electroplating process offers an attractive alternative to cadmium plating 10
Yale adopts a tuition deferment system by which graduates can gradually repay education costs from earned income 11
Funding for the nuclear rocket engine program has been cut back because of a slowdown in the U.S. space program 11
February 8,1971
JUVENILE HORMONE RESEARCH With the virtual banning of DDT and other persistent chemical pesticides, and the likelihood of tough pesticide legislation in the offing, crop scientists, farmers, chemical industrialists, and the ecologyminded public are pinning their hopes on the early emergence of what are being called third-generation pesticides. These are extremely potent compounds, so highly selective in their action that they scarcely affect the surrounding biosphere. The fortunes of juvenile hormone, one of the members of this class of pesticide, are boosted by results from two research laboratories. At Zoecon Corp., in Palo Alto, Calif., laboratory mice showed no sign of ill effects when fed a massive dose of the hormone and one of its analogs [Nature New Biology, 229, 158 (1971)]. And Stauffer Chemical scientists are guardedly enthusiastic about the outcome of recently completed field trials in which juvenile hormone analogs brought sterility and death to larvae known as tobacco bud worms and cotton bollworms which damage crops in cotton-belt states. Juvenile hormone, secreted in miC&EN: Dermot O'Sullivan
AEC's closing of Hanford nuclear reactors shocks area officials and employees, but one reactor may be kept in operation 12
Government groups discuss plans to tax sulfur in fossil fuels as well as set national air quality standards for six air pollutants 12
Zoecon's Siddall
nute quantities by insects, is a key factor in their normal growth and development. First isolated from the abdomens of Cecropia moths by Harvard's Dr. Carroll M. Williams in 1954, the compound has since been chemically characterized and synthesized. Indeed, many hundreds of analogs have now been made, and more than a dozen companies and university research teams in this country and abroad have programs under way to investigate various aspects of the juvenile hormone picture. Until now, however, there have been no definitive mammalian toxicology studies on the compounds. For their initial tests at Zoecon, Dr. John B. Siddall and Dr. Michael Slade used two lab-made compounds. One of these, trans,trans,czs-methyl 3,7,11-trimethyl-l 0,11-epoxydodeca-2,6-dienoate is the same as that made by the silk moth Hyalophera cecropia. The other compound they selected is a simple analog of it. The chemicals, suspended in vegetable oil, were introduced into the stomachs of male and female mice at single dose levels of 5000 mg. per kg. of body weight. During the 21 days that followed, the mice showed no dose-related adverse effects. Comprehensive blood analysis and a detailed examination of their livers, spleens, kidneys, and other organs showed no differences between the mice that had ingested the chemicals and those that hadn't. "These preliminary acute oral studies in mice indicate only that large quantities of an insect hormone and an analog can be tolerated on acute ingestion by one mammalian species," Dr. Siddall and Dr. Slade caution. Much work lies ahead, they point out, before juvenile hormone chemicals can rate a clean bill of health from a mammalian toxicological standpoint. The two chemists are now planning extensive tests that involve a variety of ways of administering the chemicals to different animals. FEB. 8, 1971 C&EN 9
