title: DNA synthesis in the imaginal wing discs of the American bollworm Helicoverpa armigera (Hübner).
abstract: The effect of two insect growth regulators of plant origin viz. plumbagin and azadirachtin and the ecdysteroids 20-hydroxyecdysone, makisterone A and a phytoecdysteroid on DNA synthesis in imaginal wing discs of day 4 final instar Helicoverpa armigera larvae was studied. DNA synthesis increased with increase in time of incubation up to 8 h and decreased later without the addition of moulting hormone. Addition of 20-hydroxyecdysone supported long term acquisition of competence for DNA synthesis in the wing discs. Both DNA synthesis and protein content were drastically reduced in plumbagin and azadirachtin-treated insects. Under in vitro conditions, plumbagin had a more pronounced inhibitory effect than azadirachtin. All the ecdysteroids tested, viz. makisterone A, 20-hydroxyecdysone and the ecdysteroidal fraction from the silver fern Cheilanthes farinosa enhanced DNA synthesis.
authors.affiliation: Division of Entomology, Indian Agricultural Research Institute, New Delhi 110 012, India.
authors.forename: A
authors.initials: A
authors.lastname: Josephrajkumar
authors.forename: B
authors.initials: B
authors.lastname: Subrahmanyam
mesh_terms: D000818:Animals; D004247:DNA / Q000096:biosynthesis*; D004440:Ecdysone / Q000031:analogs & derivatives* / Q000494:pharmacology; D026461:Ecdysteroids / Q000494:pharmacology; D004441:Ecdysterone / Q000494:pharmacology; D019476:Insect Proteins / Q000378:metabolism; D007306:Insecticides / Q000494:pharmacology; D007814:Larva / Q000502:physiology; D036701:Limonins; D009036:Moths / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D009285:Naphthoquinones / Q000494:pharmacology; D014315:Triterpenes / Q000494:pharmacology; D014921:Wings, Animal / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism*
chemical_list: D026461:Ecdysteroids; D019476:Insect Proteins; D007306:Insecticides; D036701:Limonins; D009285:Naphthoquinones; D014315:Triterpenes; C008310:makisterone; D004440:Ecdysone; D004441:Ecdysterone; D004247:DNA; C010329:azadirachtin; C014758:plumbagin