摘要:

AbstractKK‐42 (1‐benzyl‐5‐[(E)‐2,6‐dimethyl‐1,5‐heptadienyl]imidazole), administered by feeding, delayed the growth and development of nondiapause‐bound and diapause‐boundOstrinia nubilalislarvae and increased the length of the instar. At doses of 80–240 ppm, 62–100% of nondiapause‐bound fourth instars precociously pupated or remained as fourth instars, while 52–100% of diapause‐bound fourth instars did not molt to the fifth instar. Injection of these nondiapause‐ and diapause‐bound KK‐42‐fed fourth instars with ecdysone elicited a molt and resulted in the production of larval‐pupal intermediates. When mature fourth instar controls were similarly injected, they molted into normal fifth instars. These results support the view that KK‐42 delays/inhibits ecdysteroid production. Both eupyrene and apyrene spermiogenesis were prematurely initiated in nondiapause‐bound fourth instars that were fed on medium containing 160 ppm KK‐42. Fenoxycarb, a potent juvenile hormone mimic, rescued nondiapause‐bound fourth instars from precocious pupation. All fenoxycarbtreated larvae either molted to the fifth instar or remained as fourth instars and eventually died. These results support the view that treatment with KK‐42 inhibits JH production. When KK‐42 treatment was begun in the third instar, a considerable number of nondiapause‐bound and some diapause‐bound third instars precociously molted to the fifth instar. There was a correlation between weight and the incidence of precocious molting in that third instars destined to skip the fourth instar attained a weight, as pharate fifth instars, of two to three times more than pharate fourth instar controls. Similarly, fourth instars that were destined to undergo precocious pupation attained a weight, as pharate pupae, that was approximately two times more than pharate fifth instar controls. More potent analogues of KK‐42 may prove useful in controlling populations of0. nubilalisby interfering with their growth, development, and metamorphosis. © 1995 Witey‐Liss, Inc.This article is a US Government work and, as su

ISSN:0739-4462    

DOI:10.1002/arch.940280102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractIncubation of N‐acetyltyrosine methyl ester with cuticular enzymes, isolated from the wandering stages ofCalliphorasp larvae, resulted in the generation of N‐acetyldopa methyl ester when the reaction was carried out in the presence of ascorbate which prevented further oxidation of the o‐diphenolic product. Enzymatic oxidation of N‐acetyldopa methyl ester ultimately generated dehydro N‐acetyldopa methyl ester. The identity of enzymatically produced N‐acetyldopa methyl ester and dehydro N‐acetyldopa methyl ester has been confirmed by comparison of the ultraviolet and infrared spectral and chromatographic properties with those of authentic samples as well as by nuclear magnetic resonance studies. Since N‐acetyldopaquinone methyl ester was also converted to dehydro N‐acetyldopa methyl ester and tyrosinase was responsible for the oxidation of N‐acetyldopa methyl ester, a scheme for the cuticular phenoloxidase catalyzed conversion of N‐acetyltyrosine methyl ester to dehydro N‐acetyldopa methyl ester involving the intermediary formation of the quinone and the quinone methide is proposed to account for the observed results. The conversion of N‐acetyldopa methyl ester to dehydro derivative remarkably resembles the conversion of the sclerotizing precursor, N‐acetyldopamine, to dehydro‐N‐acetyl‐dopamine observed in the insect cuticle. Based on these comparative studies, it is proposed that peptidyl dopa derivatives could also serve as the sclerotizing precursors for the sclerotization of the insec

ISSN:0739-4462    

DOI:10.1002/arch.940280103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractPolydnaviruses from certain parasitoid Hymenoptera have been reported to interfere with both host immunity and host development.Heliothis virescenslarvae injected with either calyx fluid or sucrose gradient‐purified polydnavirus fromMicroplitis croceipes(McPDV) gained less weight than saline‐injected larvae. The active feeding portion of the fifth stadium larva (time to reach the burrowing‐digging stage) was doubled (7.0 vs. 3.4 days) when a 0.25 wasp equivalent (WE) of sucrose gradient‐purified McPDV was injected into a newly ecdysed fifth stadium host. Many of the treated larvae were unable to pupate, successfully and died at a point of incomplete larval‐pupal ecdysis. Pupae that did result from the treated larvae weighed significantly less than controls, even at 0.025 WE. The rate of weight gain and extent of delay of development were dose‐dependent; as little as 0.1 WE extended the time of active feeding by 1.5 days and yielded only 25% adults. A 0.05 WE dose yielded 78% adults compared to 95% for controls. The total protein content of hemolymph from individuals injected with McPDV was significantly less than that of controls at any McPDV dose equal to or greater than 0.1 WE. SDS‐PAGE profiles of hemolymph proteins from control and McPDV‐injected larvae revealed a marked inhibition of the normal accumulation of storage proteins during the fifth stadium and a lesser reduction of serine protease inhibitor protein. Thus, McPDV‐injected larvae exhibited some symptoms (less total hemolymph protein and reduced amounts of storage protein) similar to those shown by both parasitized larvae and by larvae injected withM. croceipesteratocytes. However, McPDV affected development during the active feeding stage of the larva, while teratocytes primarily impacted larvae at the time when larval‐pupal transformation processes are initiated. ©

ISSN:0739-4462    

DOI:10.1002/arch.940280104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe effects of the amines 5HT and octopamine on the myogenic activity ofPeriplaneta americana (L.)oviducts and the pharmacological profile of octopamine and 5HT receptors on the lateral oviducts have been determined. Application of 5HT to the oviducts resulted in a dose‐dependent increase in basal tonus and amplitude of contractions. Antagonist studies revealed that the 5HT receptor on the cockroach oviduct most resembles the mammalian 5HT2receptor. Application of octopamine resulted in a decrease in basal tonus and had a biphasic effect on the amplitude of contractions, being stimulatory at low doses and inhibitory at higher ones. The inhibitory effects of octopamine appear to be mediated via cAMP and are blocked by antagonists which indicate that the octopamine receptor is of the octopamine‐2 type. © 1995 Wiley‐Lis

ISSN:0739-4462    

DOI:10.1002/arch.940280105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractDuring the pupal molt of the tobacco hornworm,Manduca sexta, the percentage of active fat body glycogen phosphorylase increased from 5–10 to 20%, but only for a period of 5 h prior to the molt. From the time of the appearance of two sclerotized dorsal bars to the time of the molt, the concentration of total hemolymph carbohydrates doubled to 100 mM trehalose. Initially, the glucose level was high (16 mM) when compared with feeding larvae (approximately 1 mM) but decreased to zero just prior to the molt. The amount of cuticular chitosan decreased from approximately 100 mg to 10 mg at pupation; the exuvia contained approximately 7 mg. While the levels of total lipids in hemolymph were not affected, the lipid content of the fat body decreased significantly prior to the molt but increased sharply thereafter. Fat body glycogen phosphorylase in pharate pupae and pupae ofM. sextawas substantially activated by the Manduca adipokinetic peptide hormone, which in pharate pupae, produced the same response at 2 and 20 pmol per insect as in ligated larval abdomens. In pupae the response was clearly reduced. Using chilling to stimulate glycogen phosphorylase, it was found that the enzyme in pharate pupae and pupae responded both in vivo and in vitro as in ligated abdomens of larvae. Thus, a transition to the adult response seems to occur during the pupal and pharate adult development. © 1995 Wiley‐Liss,

ISSN:0739-4462    

DOI:10.1002/arch.940280106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractHypertrehalosemic hormone (HTH) up‐regulates expression of a gene for a cytochrome P450 of family 4 (CYP4C1) in the fat body of adult maleB. discoidaliscockroaches. Studies were undertaken to determine the characteristics of HTH‐dependentCYP4C1expression. A dot‐blot assay was developed for routine measurement of the relative levels of CYP4C1‐mRNA in fat body RNA extracts. A single injection of 10 pmol HTH produced a maximumCYP4C1response within 8 h. This dose corresponds with the dose needed for a maximum in vivo hypertrehalosemic response to HTH (Keeley et al., 1991). Multiple treatments with HTH at 8 or 24 h intervals were no more effective than a single treatment for producingCYP4C1expression. These results indicate thatCYP4C1expression is sensitive to physiological doses of HTH and responds rapidly.CYP4C1expression was suppressed by treatment with α‐amanitin, an inhibitor of RNA polymerase II, but was unaffected by cycloheximide, an inhibitor of protein synthesis. HTH appears to influenceCYP4C1transcription without involvement of intervening regulatory genes. These results suggest that regulation of fat bodyCYP4C1expression is a major physiological action of HTH. © 1995 Wile

ISSN:0739-4462    

DOI:10.1002/arch.940280107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940280101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY