摘要:

AbstractFollowing injection into femaleManduca sextapupae, [14C]cholesterol is converted to a radiolabeled C21nonecdysteroid conjugate as well as ecdysteroid conjugates, which in ovaries and newly‐laid eggs consist mainly of labeled 26‐hydroxyecdysone 26‐phosphate. During embryogenesis, as the level of 26‐hydroxyecdysone 26‐phosphate decreases there is a concurrent increase in the amount of a new, labeled ecdysteroid conjugate. This conjugate, which is the major ecdysteroid conjugate (9.4 μg/g) in 0‐ to 1‐hour‐old larvae was identified as 26‐hydroxyecdysone 22‐glucoside by nuclear magnetic resonance and chemical ionization mass spectrometry. This is the first ecdysteroid glucoside to be identified from an insect. The disappearance of 26‐hydroxyecdysone 26‐phosphate in 0‐ to 1‐hour‐old larvae indicates that the 26‐hydroxyecdysone 22‐glucoside is derived from 26‐hydroxyecdysone 26‐phosphate. 3‐Epi‐26‐hydroxyecdysone was the major free ecdysteroid isolated from these larvae and 3‐epi‐20,26‐dihydroxyecdysone was the next most abundant ecdysteroid isolated. Interestingly, the 0‐ to 1‐hour‐old larvae contained the highest levels of 3α‐ecdysteroids per gram of insect tissue (8.7 μg/g) to be isolated from an insect, yet there was a complete absence of the corresponding free 3β‐epimers. The ecdysteroid conjugate profiles of ovaries and 0‐ to 1‐hour‐old larvae are discussed. Methodology is presented that permits the efficient separation of free and conjugate

ISSN:0739-4462    

DOI:10.1002/arch.940040102

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

年代:1987

数据来源: WILEY

摘要:

AbstractReserpine, at doses of 20–175 μg per g body weight, severely retards oogenesis in newly emerged adult female migratory locusts (Locusta migratoria migratorioides) but does not increase mortality during the first 9 days and only slightly delays somatic growth. Total protein, and hemolymph vitellogenin content particularly, are significantly reduced in reserpine‐treated locusts. The synthesis of juvenile hormone III (JH‐III) following adult emergence, essential for induction of vitellogenesis and subsequent oogenesis, is dependent on the maturation and activation of the corpora allata (CA). CA of 7‐ to 8‐day‐old female locusts, treated with reserpine at day 1 after adult emergence, are only marginally active in vitro and are only slightly stimulated by an allatotropic factor. The basal activity and response of CA from the reserpine‐treated locusts resembles that of newly emerged locusts, suggesting that reserpine specifically retards the initial maturation of the locust CA. Recovery of basal CA activity is evident on days 12–13 in reserpine‐treated locusts, but responsiveness to the allatotropic factor is not recovered. Starvation of newly emerged females for 3 days and subsequent feeding did not effect ooctye development or CA activity. Cerebral content of the allatotropic factor, assayed on days 7–8, is not reduced by the

ISSN:0739-4462    

DOI:10.1002/arch.940040103

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

年代:1987

数据来源: WILEY

摘要:

AbstractA complexSarcophaga bullatapupariation assay was used to evaluate the neurotropic effects of several drugs, venoms, and insecticides. The assay consists of tests for (1) immediate effects on the intact larva, (2) effects on ligated (ie, isolated from the central nervous system) larval abdomens, (3) morphogenetic effects on the puparium, and (4) effects on stereotyped pupariation behavior. The latter are monitored barographically by recording changes in hemocoelic pressure. Of 62 compounds screened, 18 showed morphogenetic activity at a threshold dose of 5 μg or less, 11 at a dose of 50 μg, four at a dose of 100 μg, and 29 showed no morphogenetic activity. From a comparison of the putative pharmacological actions of the tested compounds with their morphogenetic effects, certain generalizations can be made: Agents that paralyze neuromuscular systems at the peripheral level (eg, tetrodotoxin), or suppress or modify basic motor patterns centrally (eg, veratrine sulphate), cause retention of larval morphological characters in the puparium. Compounds that stimulate convulsive contractions of segmental musculature (mostly cholinergic drugs like eserine sulphate, nicotine, organophosphate insecticides) cause retention of larval segmentation on longitudinally contracted puparia. Five compounds (venom of the scorpion,Leirus quinquestriatus, pyrethrins, protoveratrine A, and kainic and quisqualic acids) stimulate musculature of the denervated abdomen. Barographic monitoring of changes in pupariation behavior appears to be a most sensitive and informative test. It reveals great differences in the ways in which compounds producing seemingly identical morphogenetic effects affect and modify behavior, thus making pharmacological classification more accura

ISSN:0739-4462    

DOI:10.1002/arch.940040104

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe oviducal muscles of the locust,Locusta migratoria, contract in a spontaneous and rhythmic fashion when isolated from the central nervous system. Hemolymph of ovipositing females, when added to isolated locust oviducts, altered the spontaneous contractility of the oviduct. This response was not evident after addition of hemolymph from a nonovipositing female and was still present after addition of the α‐aminergic receptor antagonist, phentolamine.Oviducts in which mature eggs were present responded to homogenates of the corpus cardiacum by increasing both the frequency and amplitude of muscular contraction, whereas oviducts devoid of eggs showed no response. Extracts of ventral nerve cord also increased the spontaneous activity of the oviduct musculature. Although the muscles of the oviduct responded to homogenates of the brain, this response differed in two ways from the response due to corpus cardiacum homogenates. First, oviducts devoid of mature eggs responded to brain homogenates; and second, the response caused by the brain homogenates could be eliminated by the addition of 1 μM phenoxybenzamine. The significance of these results is discus

ISSN:0739-4462    

DOI:10.1002/arch.940040105

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

年代:1987

数据来源: WILEY

摘要:

AbstractLarvae ofSpodoptera litura(F.) grown on an artificial diet completed larval development in 19.2 days and attained a maximum weight of 873.2 mg. When fed dietary concentrations of 50 ppm of 25‐azacholesterol or 10 ppm of 25‐azacholestane, the larval developmental period increased to 28.4 and 23.4 days, and the larval weights were 447.5 and 542.3 mg, respectively. Both compounds induced distinct melanization effects and caused production of larval‐pupal intermediates and severe mortality. Treatments with concentrations of 50 ppm or more of either azasteroid caused a decline in pupal period and earlier eclosion and emergence of abnormal adults. Egg laying and hatchability decreased with increasing concentrations of azasteroids in the larval diets.When 1 ppm or more of 25‐azasteroid is added to the artificial diet, the insect larvae contain identifiable amounts of desmosterol, in addition to cholesterol, campesterol, and sitosterol, which are present inSpodopteragrown on artificial diet alone. Desmosterol accumulation in the insect body is due to an inhibition of the Δ24‐sterol reductase by 25‐azasteroids. An increase in the concentration of these azasteroids in the diet results in an increase in sitosterol concentration and simultaneous reduction in the cholesterol levels due to inhibition of conversion of sitosterol. This inhibition appears to be more pronounced with 25‐azacholestane treatment than with 25

ISSN:0739-4462    

DOI:10.1002/arch.940040106

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

年代:1987

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940040107

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

年代:1987

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940040108

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

年代:1987

数据来源: WILEY

ISSN:0739-4462    

DOI:10.1002/arch.940040101

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

年代:1987

数据来源: WILEY