|Trisyono, Andi - UNIV OF MO|
|Chippendale, G - UNIV OF MISSOURI|
Submitted to: In Vitro Cellular And Developmental Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 29, 1999
Publication Date: N/A
Interpretive Summary: Insects cause billions of dollars of damage to crops in the U.S. annually. Chemical insecticides may help control pest insects and increase crop yields, but often these chemicals can also harm beneficial insects, wildlife and people. A safe way of controlling insects is by using Insect Growth Regulators (IGRs), chemicals which specifically disrupt the growth and development of pest insects but do not harm other organisms. The IGRs we studied are those which affect insects in a way similar to the hormone ecdysone, an insect hormone important in molting. Molting is the process whereby insects shed their outer "skin", enabling them to grow into larger caterpillars and, eventually, moths (in the case of our insect). The IGRs we are studying cause insects to die by causing them to molt prematurely. Presently, an efficient means of screening chemicals with ecdysone-like properties is needed, as well as a system to help us better understand the effects of these chemicals on insects. In the present study, eggs from an important pest insect of corn, the European corn borer, were crushed and the resulting tissues were put into sterile containers. Cells grew from these tissues and began dividing on their own, creating what is called a continuously-growing cell culture. The egg cell culture responded to ecdysone and specific IGRs by clumping, an action which indicates sensitivity to these compounds. Therefore, this cell culture can be used to help screen compounds for their ability to act similar to or inhibit the action of ecdysone, as well as to study the effects of chemicals on insect cells. The overall impact of the development of this insect cell culture is that it will help scientists find new IGRs which can eventually be marketed to farmers to serve as a safe means of insect control.
Technical Abstract: A cell line derived from embryonic tissues of the European corn borer, Ostrinia nubilalis (UMC-OnE), was established in EX-CELL 401 medium containing 10% fetal bovine serum. The cells grew in suspension and were mainly spherical in shape. The cell doubling times at the 17th and 79th passages were 56 hours and 36 hours, respectively. DNA amplification fingerprinting (DAF) showed that the DNA profile of the OnE cell line was different from that of the southwestern corn borer, Diatraea grandiosella (UMC-DgE), and that of the cotton bollworm, Helicoverpa zea (BCIRL-Hz-AM1). The OnE cell line was responsive to treatments of 20-hydroxyecdysone and the ecdysone agonists, methoxyfenozide (RH-2485) and tebufenozide (RH- 5992). These compounds caused similar effects on the cells which included cell clumping and decreased cell proliferation. The clumps were observed on the third day after incubation and became larger after 7 days of incubation.