bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of juvenile hormone‐binding proteins of hemolymph of Locusta migratoria
Authors: Roberts P. Elaine 
Published: February 2005

AbstractThe binding of juvenile hormone (JH) by components from hemolymph of adult female Locusta migratoria was characterized to establish whether hemolymph JH‐binding proteins could be distinguished from a protein of fat body (BP‐1) that may be a JH receptor. Hemolymph was analyzed by the hydroxyapatite assay, gel separation chromatography, polyacrylamide gel electrophoresis, and density gradient centrifugation. Three fractions that bound JH were separated from whole hemolymph by DEAE cellulose column chromatography, and these differed from all three cytosol‐binding components. The major hemolymph component (H‐A) showed relatively stable binding of JH, a slight loss of binding capacity after delipidation, and a Kd for JH‐I of 16 nM. The Kds for JH‐l and JH‐lll with unfractionated hemolymph were 26 and 42 nM respectively. The order of effectiveness of competitors for binding of [3H]JH‐l was JH‐lll > JH‐l ≫ methoprene > hydroprene ≫ acids of methoprene and hydroprene. The data indicated that unlabeled JH‐lll was bound more effectively than its radioactive counterpart. The sedimentation values determined by sucrose density gradient ultracentrifugation were 13‐14 S for hemolymph, and the sedimentation value was not altered by the inclusion of 0.4 M KCl throughout the gradient. The data indicated that H‐A resembled the specific JH carriers and differed from the putative receptor of fat body cytosol by several criteria.
Critical roles for juvenile hormone and its esterase+ in the prepupa of Trichoplusia ni
Authors: Jones Grace , Hammock Bruce D. 
Published: February 2005

AbstractIn the caterpillar Trichoplusia ni (Lepidoptera: Noctuidae) it has been demonstrated by allatectomy that the appearance of juvenile hormone during the prepupal stage is crucial for the successful larval‐pupal ecdysis of most larvae. Application of juvenile hormone or juvenile hormone esterase inhibitors at key times disrupted normal development as well. Thus the subsequent disappearance of juvenile hormone is regulated by degradation by juvenile hormone esterase in addition to a hypothetical reduction in biosynthesis. This reduction in juvenile hormone titer in the prepupa is just as critical for normal development as was its previous appearance. These observations on the critical role of juvenile hormone in the prepupa are in contrast to observations in some other species. For instance, in the case of Manduca sexta (Lepidoptera: Sphingidae), juvenile hormone is considered only supplementary to the action of prothoracicotropic hormone in the postwandering stage and primarily is required for normal pupal development. It thus appears that even within the Lepidoptera the role of juvenile hormone in prepupal development can vary dramatically.
The role of the male accessory gland fluid in stimulating vitellogenesis in Aedes taeniorhynchus
Authors: Borovsky Dov 
Published: February 2005

AbstractInjection of 20‐hydroxyecdysone (20‐OH‐ecdysone) at high concentrations (5.0 μg) into intact or decapitated female Aedes taeniorhynchus induced vitellogenin synthesis, whereas low concentrations (5.0 ng) were ineffective. Injections of male accessory gland fluid (MAGF), however, at a concentration that was equivalent to 0.25 of the content of a pair of accessory glands, into intact or decapitated A. taeniorhynchus induced viteliogenin synthesis only in intact females. Ovariectomized mosquitoes did not synthesize vitellogenin after MAGF injection or blood feeding. Females that were first injected with MAGF and decapitated 12 h later synthesized viteliogenin at a rate that was 80% of intact controls.Egg development neurosecretory hormone (EDNH) activity in the heads of ovariectomized or intact females injected with MAGF was 9.0 pmol/min/head and 2.5 pmol/min/head, respectively, indicating that MAGF does not stimulate the corpus cardiacum (CC) to release EDNH.Incubation of MAGF and EDNH with fat bodies failed to induce vitellogenin synthesis. These results indicate that in A. taeniorhynchus the MAGF induces the ovary to release corpus cardiacum stimulating factor, which then signals CC to release stored EDNH.
Properties of the Δ11‐desaturase enzyme used in cabbage looper moth sex pheromone biosynthesis
Authors: Wolf Walter A. , Roelofs Wendell L. 
Published: February 2005

AbstractThe biosynthesis of a large number of sex pheromone components of various moth species can be explained by invoking a Δ 11‐desaturation of common fatty acids. A Δ11‐desaturase system from Trichoplusia ni, the cabbage looper moth, is identified and partially purified. Some of its properties are defined and compared with those of the ubiquitous Δ‐9 desaturase enzyme. Similarities between the two systems include subcellular location (microsomal), substrate specificity (16‐ and 18‐carbon acids), and lack of sensitivity to carbon monoxide, while differences include cofactor preference (NADH rather than NADPH), sensitivity to cyanide ion, pH optimum (7.4‐7.8 vs 6.8‐7.2), and location in the organism (in the pheromone gland compared to generally distributed). The effects of insect age were also investigated.
Comparison of some properties of the high‐affinity juvenile hormone binding protein from the larval hemolymph of pyralid moths
Authors: Lenz C. J. , Dillwith J. W. , Chippendale G. M. 
Published: February 2005

AbstractThe properties of the high‐affinity low molecular weight juvenile hormone (JH) binding protein present in the hemolymph of larvae of five species of pyralid moths, a noctuid moth, and a sphingid moth were compared. The pyralid moths exhibit a facultative diapause as last‐instar larvae. The species employed were the southwestern corn borer, Diatraea grandiosella, the southern cornstalk borer, Diatraea crambidoides, the sugarcane borer, Diatraea saccharalis, the European corn borer, Ostrinia nubilalis, the sunflower moth, Homoeosoma electellum, the cabbage looper, Trichoplusia ni, and the tobacco hornworm, Manduca sexta. The binding characteristics of the proteins were determined using saturation binding assays and competitive binding assays. The dissociation constants of JH I, JH II, and JH III for the binding protein of all the species varied from 0.8 x 10−7 M to 2.8 x 10−7 M. Calibrated gel filtration showed that the binding protein of all the species had apparent molecular weights ranging from 29,000 to 31,000. Electrophoresis in 7% acrylamide gels revealed that the relative mobilities of the binding proteins ranged from 0.33 to 0.43. Isoelectric focusing showed that the binding proteins had isoelectric points between 4.4 and 5.0.
In vitro ecdysteroid conjugation by enzymes of Manduca sexta midgut cytosol
Authors: Weirich Gunter F. , Thompson Malcolm J. , Svoboda James A. 
Published: February 2005

AbstractIn incubations with 80,000g supernatant of Manduca sexta midgut homogenates, [3H]ecdysone was converted to 3‐[3H]epiecdysone and tritiumlabeled highly polar metabolites. C18 SEP‐PAK cartridges were found suitable for the separation and purification of the free ecdysteroids and of the highly polar metabolites. Eighty to ninety percent of the metabolites were hydrolyzed by enzyme mixtures (mainly β‐glucuronidase, sulphatase, and acid phosphatase) from molluscs, even when β‐glucuronidase activity was completely inhibited by D‐saccharic acid 1,4‐lactone, or various human acid phosphatases (free of sulphatase activity). In each experiment, the hydrolysate contained a much higher proportion of 3‐epiecydsone than the free (unconjugated) ecdysteroid fraction. [3H]ecdysone was not metabolized in anaerobic incubations of midgut supernatant that had been filtered through Sephadex G‐25. Addition of 5 mM ATP and 5 mM Mg2+ restored the conjugate formation in incubations of Sephadex‐filtered supernatant. Four ecdysone conjugates and two 3‐epiecdysone conjugates were resolved by reversedphase ion‐pair high‐performance liquid chromatography. It is concluded that the midgut cytosol contains several ATP:ecdysteriod phosphotransferases. This is the first demonstration of the formation of ecdysteroid phosphoconjugates in a cell‐free system.
Modulatory effects of octopamine and serotonin on male sensitivity and periodicity of response to sex pheromone in the cabbage looper moth, Trichoplusia ni
Authors: Linn C. E. , Roelofs W. L. 
Published: February 2005

AbstractThe pheromone‐mediated flight behavior of male cabbage looper moths in a sustained‐flight tunnel and random activity exhibited during scotophase were observed after males were treated with octopamine or serotonin (5 hydroxytryptamine). Octopamine induced a hypersensitivity to the olfactory signal, resulting in a significant lowering of the pheromone dose that elicited peak levels of response. Octopamine, however, did not affect the circadian rhythmicity of response to pheromone. In contrast, serotonin disrupted the circadian rhythmicity of response, resulting in a high percentage of males exhibiting random activity and response to pheromone throughout the entire 8 h scotophase instead of during the normal peak period during the latter part of the scotophase. Serotonin did not effect a decrease in the dose of pheromone eliciting peak response. In addition, at the highest dosages tested octopamine and serotonin induced opposite postures associated with a paralysis that occurred when males attempted to take flight to the pheromone.
Possible inactivation of ingested ecdysteroids by conjugation with long‐chain fatty acids in the female tick Ornithodoros moubata (acarina:argasidae)
Authors: Connat J.‐L. , Diehl P. A. , Thompson M. J. 
Published: February 2005

AbstractOrnithodoros moubata females proved to be extremely sensitive to ingested 22,25‐dideoxyecdysone; 15‐20 ng provoked molting in all females and temporarily inhibited vitellogenesis. In contrast, this tick was very resistant to ingested ecdysteroids containing 22‐OH groups, such as ecdysone, 20‐hydroxyecdysone, ponasterone A, and makisterone A. Dosages about 500 times greater were necessary to produce supermolting and reduce fecundity [Connat et al: Z Ang Ent 96, 520 (1983)]. Ingested tritiated ecdysone, 20‐hydroxyecdysone, 2‐deoxyecdysone, and ponasterone A were rapidly converted to apolar esterase‐labile metabolites having approximately the same retention time as the AP2 identified as esters of ecdysteroids at C‐22 with long‐chain fatty acids (C16:0, C18:0, C18:1, C18:2) [Diehl et al: Int J Invert Reprod Dev 8, 1 (1985)]. These products were then gradually transformed to the more polar apolar conjugates, AP1. A more detailed study with ingestion of large quantities of 20‐hydroxyecdysone (10 μ/ml blood) demonstrated that only small amounts of free hormone were present in the hemolymph during the first day after the blood meal. The hormone was rapidly metabolized to AP2, then to AP1, in the intestinal cells and to a lesser extent in the peripheral tissues. Finally, AP1 accumulated in the intestinal cells and midgut content, probably because excretion outside the animal is impossible in this tick species.In contrast, ingested 22,25‐dideoxyecdysone was not metabolized to apolar products. This could account for its high biological activity. This compound was converted to unidentified more polar products. Two of them comigrated with ecdysone and 20‐hydroxyecdysone on RP‐18 HPLC column, but not on silica column, and therefore cannot correspond to these compounds.We hypothesize that esterification of ecdysteroids at the C‐22 position with fatty acids represents a detoxification mechanism for ingested ecdysteroids that might be present in blood from herbivorous or parasite‐infected hosts.
Change in corpus allatum function during metamorphosis of the tobacco hornworm Manduca sexta: Regulation at the terminal step in juvenile hormone biosynthesis
Authors: Bhaskaran Govindan , Sparagana Steven P. , Barrera Punnee , Dahm Karl H. 
Published: February 2005

AbstractChanges in activity of the corpora allata (CA) during larval‐pupal‐adult development of the tobacco hornworm Manduca sexta were studied by transplantation assays, measurements of in vitro juvenile hormone (JH) and JH acid synthesis, and determination of JH acid methyltransferase (JHAMT) and 3‐hydroxy‐3‐methylglutaryl coenzyme A (HMG‐CoA) reductase activities. The data from these assays demonstrate that the CA cease to secrete JH by day 4 of the last larval instar (wandering stage). With regard to JH synthesis, they remain inactive throughout the prepupal, pupal, and most of the pharate adult periods. CA of females, but not of males, resume JH synthesis shortly before eclosion. The biochemical basis of the inactivation process is the loss of JHAMT activity. However, prepupal CA produce JH acids, as shown by enzyme and in vitro assays. Pupal and pharate adult CA do not synthesize JH acids although levels of HMG‐CoA reductase activity seem to remain relatively high. Radiolabeled JH was recovered from hemolymph of allatectomized prepupae that had been injected with radiolabeled JH acid. These results provide further evidence that certain peripheral tissues (eg, imaginal discs) convert JH acid secreted by the prepupal CA to JH and, thus, that JH acid is a prohormone in the prepupal period. The CA change from hormone secretion to prohormone secretion during larval‐prepupal transformation, a unique functional alteration in an endocrine gland.
Mitochondrial biogenesis during spermatogenesis in Heliothis virescens, H. subflexa, and their male‐sterile backcross hybrids
Authors: Miller Stephen G. , Huettel Milton D. 
Published: February 2005

AbstractThe mitochondrial proteins synthesized by spermatogenic cells from Heliothis virescens, H. subflexa, and their male‐sterile backcross progeny were analyzed by using two‐dimensional gel electrophoresis. This subset of total cellular proteins was defined by using a combination of cellular fractionation techniques and pulse‐labeling in the presence of antibiotics. Mitochondrial morphology was also evaluated in cells from fertile and sterile testes by using the laser dye rhodamine 123. These studies revealed that while abnormal mitochondrial structures are apparent in sperm from backcross moths, neither protein synthesis nor import into the organelle was affected in these individuals. Two mitochondrial proteins exhibiting charge variation between the two parental hybridizing species have been identified, and these results are discussed within the context of a hypothesis developed to account for the sterility phenomenon.
Biosynthesis of makisterone A and 20‐hydroxyecdysone from labeled sterols by the honey bee, Apis mellifera
Authors: Feldlaufer M. F. , Herbert E. W. , Svoboda J. A. , Thompson M. J. 
Published: February 2005

AbstractIn an effort to determine the sterol precursor(s) of the 28‐carbon ecdysteroid, makisterone A, honey bee pupae (13 days post‐oviposition) were injected with radiolabeled sterols and subsequently examined for labeled ecdysteroids. High performance liquid chromatography of the pupal extracts revealed that [3H]campesterol was converted to a compound that behaved chromatographically identical to authentic makisterone A, and [14C]cholesterol was incorporated into a compound chromatographically like 20‐hydroxyecdysone. No incorporation of either 24‐[3H]methylenecholesterol or [14C]sitosterol into an ecdysteroid was observed. The neutral sterols of uninjected honey bee pupae contained 49.8% 24‐methylenecholesterol on a relative percent basis and, with three other C28 and C29 sterols, accounted for over 99% of the total sterols present.
The neutral sterols of Megalotomus quinquespinosus (say) (hemiptera: Alydidae) and identification of makisterone a as the major free ecdysteroid
Authors: Feldlaufer M. F. , Svoboda J. A. , Aldrich J. R. , Lusby W. R. 
Published: February 2005

AbstractLast‐stage nymphs of the broad‐headed bug, Megalotomus quinquespinosus contain the C28 ecdysteroid makisterone A as their major ecdysteroid. No ecdysone or 20‐hydroxyecdysone was detected in whole body extracts analyzed by high performance liquid chromatography and radioimmune assay. Analyses of the neutral sterols of this phytophagous hemipteran revealed that the sterol composition of the nymphs was highly reflective of their dietary sterols. The most abundant nymphal sterols were sitosterol (46.6%), Δ7‐stigmastenol (13.8%) and spinasterol (13.4%). Cholesterol accounted for only 0.2% of the total sterols and indicates that this species is incapable of converting 24‐alkyl sterols to cholesterol.
Maturation of locust corpora allata during the reproductive cycle: Effect of reserpine on allatotropic activity, juvenile hormone‐III biosynthesis, and oocyte development
Authors: Gadot Michal , Faktor Ouriel , Applebaum Shalom W. 
Published: February 2005

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 reserpine treatment.
25‐Azasteroid inhibition of development and conversion of C28 and C29 phytosterols to cholesterol in Spodoptera litura (F.)
Authors: Kuthiala A. , Agarwal H. C. , Thompson Malcolm J. , Svoboda James A. 
Published: February 2005

AbstractLarvae of Spodoptera 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 in Spodoptera grown 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‐azacholesterol.
Synergistic action of diethyl maleate on the morphogenetic and antigonadotropic activity of precocenes on the seed bug Oxycarenus Iavaterae (F.)
Authors: Bellés X. , Baldellou M. , Messeguer A. 
Published: February 2005

AbstractFreshly ecdysed‐third instar larvae and adult females of the seed bug Oxycarenus Iavaterae were treated with diethyl maleate (1 or 10 μg/specimen, topically applied), a commonly used depletor of glutathione levels, prior to the application of model precocenes (P1, P2, and EP2; 1–10 μg/specimen, topically applied). The combined treatment resulted in a significant increase of the characteristic antijuvenile hormone effects elicited by the above allatocidins, namely, induction of precocious metamorphosis in larvae and inhibition of ovarian development in adult females. These results, which indicated that diethyl maleate exerted a definite synergistic action, constitute the first example of a synergism strategy to the improvement of precocene activity.
Effects of starvation, chilling, and injury on endocrine gland function in Galleria mellonella
Authors: Malá Jaroslava , Sehnal Frantisek , Kumaran A. Krishna , Granger Noelle A. 
Published: February 2005

AbstractStarvation, chilling, and injury of last instar Galleria mellonella larvae typically elicit extra larval molts or a delay in pupation. The primary sites of action and the nature of the signals by which these treatments affect development are not known. However, since the connections of the brain to the nerve cord are crucial for the effects of starvation and chilling, these signals apparently affect the brain‐centered program of developmental regulation via the nerve cord. Chilling, and occasionally starvation, cause extra larval molts in last instar larvae treated prior to the nervous inhibition of their corpora allata; release of a cerebral allatotropin, which stimulates the production of juvenile hormone, appears to be involved in this effect. After this time, a delay in pupation is the principal effect of starvation and chilling, and is apparently due to a temporal inhibition of the release of the prothoracicotropic hormone. Chilling also appears to inhibit unstimulated ecdysteroid production by the prothoracic glands.The effect of injury is not mediated by the nerve cord, but appears to involve an inhibitory humoral factor that affects either the brain or the prothoracic glands themselves. Injury also stimulates juvenile hormone production, an effect which is enhanced when the brain is separated from the nerve cord and which is evidenced by a delay of ecdysis and the occasional retention of some larval features in the ecdysed insects.None of the effects of these various treatments on the brain and the endocrine glands persist when the brains or glands are implanted into untreated hosts.
Disruption of antennal morphogenesis in Bracon hebetor by exposure to triethylamine
Authors: Abbott Barbara D. 
Published: February 2005

AbstractExposing third instar larvae of the wasp Bracon hebetor to triethylamine (TEA) results in malformed antennae in eclosing adults. The purpose of this research was to examine the effects of TEA at the cellular level. Rate of growth of treated antennal buds (56–76 h) and mean size (76–96 h) were significantly reduced. Internal pH was elevated for 5 h after TEA exposure. Cell size remained constant except in treated buds from 76 to 96 h, when diameter was reduced. The mean mitotic index (MI) was reduced and a normal peak at 72–76 h was eliminated. Cell death (DI) increased. Increased DI and decreased MI from 0 to 5 hours after exposure are attributed to increased pH. TEA can form reactive alkylating intermediates, and loss of the MI peak 12 h after exposure accompanied by increased DI may be due to alkylation. It is concluded that the reduced number of segments is due to an overall reduction in total number of cells. Abnormal segmentation may involve alkylation induced somatic mutations.