bluuebunny/crossref_metadata_2025_split huggingface dataset:
Initiation of vitellogenesis in pharate adult females of the Indianmeal moth, Plodia interpunctella
Authors: Shirk Paul D. , Zimowska Grażyna , Silhacek Donald L. , Shaaya Eli 
Published: February 2005

AbstractEgg maturation in the Indianmeal moth, Plodia interpunctella (Hübner), is initiated during adult metamorphosis. The temporal sequence for the initiation of vitellogenin (Vg) synthesis in fat body, the accumulation of Vg in hemolymph, and the accumulation of yolk proteins in terminal follicles during adult development are described. On the basis of quantitation by rocket immunoelectrophoresis, the amount of Vg in hemolymph prior to 80 h after pupation was below 50 ng/μl hemolymph. At 83 h after pupation, Vg was detectable at 0.4 μg/μl hemolymph and increased to over 20 μg/μl within 24 h after adult eclosion. Using immunofluorescent histochemical staining for Vg subunit yolk polypeptide 1 (YP1), the production of Vg was observed to increase rapidly in fat body between 96 and 100 h after pupation. Western blot analysis showed that YP2 was the first YP to accumulate in terminal follicles appearing at 96 h after pupation while the other three major YPs were first observed at 116 h. These findings demonstrate that initiation of vitellogenesis in terminal follicles begins around 96 h after pupation and involves the temporal coordination of fat body and follicle activities that provide Vgs before terminal follicles achieve competency to accumulate yolk proteins. © 1992 Wiley‐Liss, Inc.
Effects of RH 5849, the first nonsteroidal ecdysteroid agonist, on larvae of Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)
Authors: Smagghe Guy , Degheele Danny 
Published: February 2005

AbstractThe effects of RH 5849 on the larval molt and larval‐pupal metamorphosis in Spodoptera littoralis (Boisd.) were examined. Application of RH 5849 to newly ecdysed 3rd and 6th (last) instar larvae induced a larval molt within the first day after application. Symptoms included cessation of feeding and larval weight, extrusion of gut, loss of hemolymph, and a developmentally abnormal and subsequent lethal larval ecdysis. Treated larvae died shortly afterwards. Treated 6th instar larvae, which did not appear to be affected before pupation, showed an abnormal and lethal pupation process.Differences in the protein pattern of the cuticle between treated vs. untreated 6th instar larvae, demonstrated by using PAGE, indicated that in the newly induced larval cuticle some proteins were missing or expressed with less intensity. The lack of several bands in the pattern of cuticular and hemolymph proteins of treated vs. untreated 6th instar larvae, probably from proteins specific for the pupal instar, is suggested as a cause of unsuccessful pupation in the treatment. © 1992 Wiley‐Liss, Inc.
Hemolymph concentrations of host ecdysteroids are strongly suppressed in precocious prepupae of Trichoplusia ni parasitized and pseudoparasitized by Chelonus near curvimaculatus
Authors: Jones Davy , Gelman Dale , Loeb Marcia 
Published: February 2005

AbstractRegulation of ecdysteroid production in lepidopteran prepupae was studied using a parasitic wasp (C. near curvimaculatus) which specifically suppresses host prepupal ecdysteroid production after the induction of precocious host metamorphosis. At the developmental stage at which the hemolymph of the unparasitized metamorphosing host has its maximum titer of prepupal ecdysteroids, the hemolymph of 4th instar “truly parasitized” hosts (hosts with a surviving endoparasite) had a strongly reduced ecdysteroid titer. However, during the photophase about 12 h later, just prior to emergence of the parasite larva, an ecdysteroid peak was observed in the host hemolymph. Fourth instar pseudoparasitized prepupal hosts (in which the endoparasite was not present or died early in development) exhibited a sustained suppression in the hemolymph ecdysteroid titer. Small 5th instar pseudoparasitized hosts, which normally would molt to a 6th instar prior to metamorphosis, but which precociously attained the prepupal stage, also had a strongly reduced ecdysteroid titer. The late increase observed in truly parasitized hosts could be completely prevented by surgical removal of the parasite 24 h earlier, resulting in a titer similar to that in pseudoparasitized hosts. HPLC analysis of ecdysteroids in normal, truly parasitized, and 4th or 5th instar pseudoparasitized prepupae showed that both ecdysone and 20‐OH ecdysoneAbbreviations used: 20‐OH ecdysone = 20‐hydroxyecdysone; 20, 26‐OH ecdysone = 20, 26 dihydroxyecdysone; PTTH = prothoracicotropic hormone.
were suppressed in truly and pseudoparasitized prepupae, with ecdysteroid levels being lowest in pseudoparasitized hosts. These data, and those of Brown and Reed‐Larsen (Biol Contr 1, 136[1992]), showing endoparasite secretion of ecdysteroids just prior to its emergence from the host, strongly indicate that: (1) the prepupal peak in truly parasitized hosts originates from the endoparasite, and (2) the low level of ecdysteroids in pseudoparasitized hosts results from the host's intrinsic inability to express a normal level of prepupal ecdysteroid titer. While precocious 4th or 5th instar prepupae of similar size had similarly suppressed ecdysteroid titers, smaller 4th instar prepupae had a lower ecdysteroid titer than larger, precocious 5th instar prepupae. Rare 5th instar pseudoparasitized prepupae that were of nearly normal size showed a prepupal ecdysteroid titer distinctly greater than those of the usual smaller, precocious 5th instar prepupae. The data suggest that the competence of the host to express a normal hemolymph titer of prepupal ecdysteroids is more closely correlated with the size of the prepupae than with the instar attained. © 1992 Wiley‐Liss, Inc.
ATP‐dependent Ca2+ transport and Ca2+‐ATPase activities in an enriched plasma membrane fraction from gypsy moth larval midgut tissue
Authors: Sheppard Carol Anelli , Loeb Marcia J. 
Published: February 2005

AbstractA subcellular fraction enriched in plasma membranes was obtained from gypsy moth (Lymantria dispar) larval midgut tissue. Using [45Ca]2+ as a tracer, Ca2+ transport activity by membrane vesicles in the enriched fraction was measured and shown to be ATP‐dependent, with a very high affinity for Ca2+ (apparent Km for [Ca2+ free]Abbreviations used: [Ca2+free] = concentration of free (unbound) calcium ion;CaM = calmodulin; F = fraction; IOV = inside‐out membrane vesicles; W‐5 = N‐(6‐aminohexyl)‐1‐naphthalenesulfonamide; W‐7 = N‐(6‐aminohexyl)‐5‐chloro‐1‐naphthalenesulfonamide.
= 22 nM). Ca2+ transport was abolished upon addition of the calcium ionophore, A23187. Ca2+‐stimulated, Mg2+‐dependent ATPase activity peaked between 100 and 200 nM Ca2+free. Ca2+‐Mg2+‐ATPase activity was inhibited by vanadate, 2 phenothiazine drugs (trifluoperazine and chlorpromazine), and the naphthalene sulfonamide, W‐7; the related compound, W‐5, and ouabain had a negligible effect. These results suggest the presence of a high affinity plasma membrane Ca2+ pump in gypsy moth larval midgut cells and are discussed in light of earlier work involving calcium transport in isolated midguts of larval Hyalophora cecropia. Ionic and other conditions that characterize the midgut physiology of larval Lepidoptera (e.g., luminal pH; electrochemical gradient for Ca2+; effect of certain ions and inhibitors on Ca2+ transport) contrast significantly with those found in adult Diptera. The implications that these differences may have for calcium regulation are discussed. © 1992 Wiley‐Liss, Inc.
Phenol β‐glucosyltransferase and β‐glucosidase activities in the tobacco hornworm larva Manduca sexta (L.): Properties and tissue localization
Authors: Ahmad Saad A. , Hopkins Theodore L. 
Published: February 2005

AbstractPhenol β‐glucosyltransferase (PGT; EC 2.4.1.35) was studied in feeding fifth stadium larvae of the tobacco hornworm, Manduca sexta, using reversed‐phase HPLC with absorbance detection to separate and quantify both the model substrate, p‐nitrophenol (PNP), and the product, p‐nitrophenyl β‐D‐glucopyranoside (PNP‐Glc). About 90% of total PGT activity in tissue homogenates was associated with the particulate fraction (15,000g), with the remainder in the microsomal fraction. PGT activity was observed in all tissues, with highest activities in the labial gland and fat body. Appreciable activity occurred in midgut and hindgut tissue but none was found in hemolymph. PGT activity was also observed in eggs and larval fat body at different times during development. Activity was optimal at pH 7.5–9 and was highest with UDP‐Glc as a glucose donor. However, appreciable PGT activity was observed with dTDP‐Glc or GDP‐Glc in place of UDP‐Glc. The divalent cations Ca2+, Co2+, Mg2+, and Mn2+ stimulated activity, whereas Zn2+ and Hg2+, as well as pretreatment with the detergent Triton X‐100, were inhibitory. Endogenous β‐glucosidase in PGT‐enriched fractions, especially from the midgut, antagonized the β‐glucossylation process, and interference was minimized with higher pH and the addition of D‐gluconic acid lactone to the incubation mixtures. The possible role of transglucosylation in the detoxication of phenolic xenobiotics and biotransformation of endogenous phenolic compounds in insects is discussed. Comparisons of PGT with some glycosyltransferases involved in endogenous and xenobiotic conjugation in insects and other organisms are reviewed. © 1992 Wiley‐Liss, Inc.
Block of voltage‐dependent K+ channels in insect muscle by the diacylhydrazine insecticide RH‐5849, 4‐aminopyridine, and quinidine
Authors: Salgado Vincent L. 
Published: February 2005

AbstractIn calcium‐free saline, voltage‐clamped ventral longitudinal muscles of housefly larvae have maintained (IK) and transient (IA) voltage‐dependent K+ currents. With 500 ms conditioning pulses, inactivation of IA had a midpoint at −53 mV and changed e‐fold in 3.46 mV. IA inactivated completely at −40 mV, with a time constant of 71 ms, allowing the effects of various K+ channel blockers to be studied on IK in isolation. RH‐5849 (1,2‐dibenzoyl‐1‐tert‐butylhydrazine), a novel insect growth regulator, induces a lethal premature molt in insect larvae by mimicking the action of the molting hormone at ecdysone receptors. RH‐5849 also causes acute neurotoxicity in some insects by selectively blocking of IK in nerve and muscle. While most channel blockers have a Hill coefficient near 1, consistent with a simple one molecule per channel block mechanism, RH‐5849 and the analog RH‐1266 were found in the present study to block IK channels in insect muscle with a Hill coefficient of 1.5. The lC50 (concentration that caused 50% block) for block of IK was 59 μM for RH‐5849 and 40 μM for RH‐1266. While tetraethylammonium blocked IK by only 20% at 100 mM, 4‐aminopyridine blocked the current with an lC50 of 1.2 mM and a Hill coefficient of 0.97. Quinidine was the most potent blocker of IK in this study, with an lC50 of 20 μM. Block of IK by either RH‐5849 or 4‐aminopyridine was independent of test pulse potential, but block by quinidine increased with depolarization. Block of IK by RH‐5849 and quinidine was time dependent, suggesting an open channel block mechanism, but the time course was too fast relative to channel activation for kinetic analysis. The lC50 for block of IK by RH‐5849 decreased with temperature, with a Q10 of 0.52. IA was also blocked by RH‐5849, but was less sensitive than IK. The lC50 for block of IA by RH‐5849 was 775 μM, 13‐fold higher than the lC50 for block of IK. © 1992 Wiley‐Liss, Inc.
Identification of yolk platelet‐associated hydrolases in the oocytes of Rhodnius prolixus
Authors: Nussenzveig Roberto H. , Oliveira Pedro L. , Masuda Hatisaburo 
Published: February 2005

AbstractThe yolk platelets from Rhodnius prolixus, a blood‐sucking bug, are composed mostly of vitellin and here are shown to contain at least two hydrolytic enzymes, a phosphatase and a cathepsin D‐like proteinase. Both the proteinase and the phosphatase have an acid pH optimum. No hydrolytic activity was observed under alkaline or neutral conditions. Among several proteinase inhibitors tested, only pepstatin could abolish vitellin breakdown in vitro. The proteinase appears to be bound to the yolk platelet membranes. The phosphatase activity, using p‐nitrophenyl phosphate as substrate, was enhanced after disruption of the platelet membrane by Triton X‐100. This activity could be inhibited by tartrate but not by p‐cloromercuribenzoate. © 1992 Wiley‐Liss, Inc.
Role of chilling in the acquisition of cold tolerance and the capacitation to express stress proteins in diapausing pharate larvae of the gypsy moth, Lymantria dispar
Authors: Denlinger David L. , Lee Richard E. , Yocum George D. , Kukal Olga 
Published: February 2005

AbstractCold hardiness in eggs (pharate first instar larvae) of the gypsy moth is not a component of the diapause program, but is acquired only after the pharate larvae have been chilled. The supercooling points of unchilled (25°C) and chilled (5°C) eggs are nearly the same (ca. −27°C), and chilling does not further elevate concentrations of glycerol, the major cryoprotectant, yet chilling at 5°C greatly increases the pharate larva's tolerance of −20°C. One conspicuous difference between the chilled and unchilled pharate larvae is their ability to express stress proteins. The most abundantly expressed stress protein, 75,000 Mr, was expressed more highly in chilled pharate larvae than in unchilled pharate larvae, both at high temperatures (> 40°C) and in response to low temperature (−15°C). This correlation suggests a link between stress protein synthesis and the acquisition of cold tolerance. © 1992 Wiley‐Liss, Inc.
Glutamate receptor inhibitors as potential insecticides
Authors: Eldefrawi Mohyee E. , Anis Nabil A. , Eldefrawi Amira T. 
Published: February 2005

AbstractPhilanthotoxin (PhTX) is a neurotoxic constituent of the paralytic venom of the digger wasp, Philanthus triangulum. PhTX inhibits glutamate receptors of insect muscles mostly as a channel blocker, thereby producing muscle paralysis. Since glutamate receptor blockers may be of value as selective insect control agents, numerous derivatives of Ph TX were synthesized and tested for their potencies as inhibitors of insect skeletal muscle glutamate receptors. Structure‐activity relationship studies revealed that shortening the polyamine chain length reduced potency, and quaternarization of the nitrogen destroyed it. The potency was increased by a bulky anchoring group with moderate hydrophobicity at the end of the polyamine chain. The conversion of the tryosyl moiety to 3,5‐diiodo‐tyrosyl also increased potency and so did lengthening the butyryl chain from 4 to 10 carbons. Not only did Ph TXs inhibit different subtypes of glutamate receptors, including the mammalian N‐methyl‐D‐aspartate receptor, but also nicotinic receptors of insects and vertebrates. Because of this low selectively, and the hydrophilicity of the derivatives tested, which interferes with their penetration to the target receptor, these compounds cannot be used as insecticides. Nevertheless, the insect skeletal muscle glutamate receptor is a viable target for selective insecticides and major changes in Ph TX structure may possibly produce derivatives that can be potential insecticides. © 1993 Wiley‐Liss, Inc.
Chemical studies of pheromone receptors in insects
Authors: Prestwich Glenn D. 
Published: February 2005

AbstractIn the current molecular model for insect olfaction, pheromones are recognized in a minimum‐energy conformation by specific receptor proteins in a dendritic membrane following their binding‐protein‐mediated transit through the extracellula sensory lymph. Binding to the receptor protein then triggers a G‐protein‐linked phospholipase C, which releases a short pulse of the second messenger inositol 1,4,5‐trisphate (IP3). IP3 may act via its receptor to mobilize Ca+ + ions, eventually leading to a transmembrane ion current; alternatively, IP3 may directly gate the ion channel. To understand this process, we have synthesized photoaffinity labels for the pheromone receptor sites and for the IP3 receptor sites. The latter probe, [125I]‐ASA‐IP3, is now being employed in joint projects to identify membrane IP3 receptors in the rat brain, locust brain, rat olfactory cilia, catfish olfactory cilia, and in cockroach and moth sensilla. Fluorine‐substituted pheromone analogs have also been synthesized as probes of receptor site hydrophobicity. The rationale for this approach is presented, and biological studies with selectively‐fluorinated analogs of (Z)‐5‐decenyl acetate (Z5‐10:Ac), (Z)‐7‐dodecenyl acetate (Z7‐12:Ac), (Z)‐9‐dodecenyl acetate (Z9‐12:Ac), (Z)‐9‐tetradecenyl acetate (Z9‐14:Ac), (Z)‐11‐hexadecenal (Z11‐16:Al), and several functional group derivatives for a number of economically important moth species are described. © 1993 Wiley‐Liss, Inc.
Insect detoxifying enzymes: Their importance in pesticide synergism and resistance
Authors: Ishaaya Isaac 
Published: February 2005

AbstractPyrethroid esterases of Trichoplusiani, Spodoptera littoralis and Bemisia tabaci hydrolyze the trans‐isomers of various pyrethroids more extensively than the cis‐isomers. Profenofos fed to T. ni larvae at a level inhibiting the gut pyrethroid esterases by 65% with trans‐permethrin and of 95% with cis‐cypermethrin increased the toxicity of topically applied trans‐permethrin by fourfold and cis‐cypermethrin by 20‐fold. Similar assays with S. littoralis resulted in an increase of about threefold in the toxicity of both compounds. Monocrotophos, profenofos, acephate, and methidathion inhibited pyrethroid esterase activity in B. tabaci and synergized considerably the toxicity of cypermethrin. The remarkable tolerance of the predator Chrysopa carnea to pyrethroids is attributed to the presence of a high level of pyrethroid esterase activity with a unique specificity for hydrolyzing the cis‐isomer. Phenyl saligenin cyclic phosphonate, a potent inhibitor for larval pyrethroid esterases synergized the toxicity of trans‐permethrin by 68‐fold from an LD50 of 17,000 μg/g to 250 μg/g. In contrast, oxidase inhibitors such as piperonyl butoxide, SV‐1, and MPP synergized considerably the toxicity of pyrethroids in Tribolium castaneum and Musca domestica. Hence the predominant pathway for pyrethroid detoxification in insects, whether hydrolytic or oxidative, depends largely on the insect species. The high toxicity of the recent developed acylureas results from their high retention in the insects. Assays using radiolabeled diflubenzuron and chlorfluazuron applied to fourth instar T. castaneum larvae revealed a rapid elimination of diflubenzuron (T1/2 ≅ 7 h) as compared with chlorfluazuron (T1/2 > 100 h). Addition of 100 ppm DEF to the diet increased both the retention time and the toxicity of diflubenzuron in both T. castaneum and S. littoralis, which was due probably to the inhibition of diflubenzuron hydrolase activity. Esterases, hydrolyzing pyrethroids, and acylureas may serve as tools for evaluating potential synergists and for monitoring resistance in various agricultural pests due to increased metabolism. © 1993 Wiley‐Liss, Inc.
Molting fluid enzymes of the tobacco hornworm, Manduca sexta: Timing of proteolytic and chitinolytic activity in relation to pre‐ecdysial development
Authors: Samuels Richard I. , Reynolds Stuart E. 
Published: February 2005

AbstractDevelopmental profiles for a number of molting fluid (MF) enzyme activities were established and related to the progress of pupal cuticle degradation during the four days that precede the eclosion of adult tobacco hornworms. Cuticle degrading activity, molting fluid protease 1 (MFP‐1), and molting fluid protease 2 (MFP‐2) all increased in activity at the time that loss of material from the old cuticle occurred. In contrast, chitinase and β‐acetylglucosaminidase activities did not parallel weight loss from the old cuticle. These results are consistent with the hypothesis that proteolytic activity is a prerequisite for the action of chitinase on cuticle chitin. © 1993 Wiley‐Liss, Inc.
Effect of allatostatin and proctolin on antennal pulsatile organ and hindgut muscle in the cockroach, Diploptera punctata
Authors: Lange Angela B. , Chan Kuen K. , Stay Barbara 
Published: February 2005

AbstractDiploptera punctata allatostatins are brain neuropeptides that inhibit juvenile hormone synthesis by corpora allata. They also occur in nerves of many organs other than ocrpora allata. The distribution of allatostatins in, and the effect of allatostatins on two other organs, antennal pulsatile organ and hindgut, are demonstrated here. Allatostatin I‐like immunoreactive material is present in cells of subesophageal and terminal abdominal ganglia; these ganglia are known to contain the cells that project to antennal heart nerve and proctodeal nerve, respectively. Electron micrographs of both organs show nerve terminals with allatostatic immunoreactive granules along with terminals containing nonimmunoreactive granules. Immunoreactive neurosecretory granules are about 200 nm in largest dimension. In the antennal pulsatile organ, profiles of the nerve terminals are larger in the ampullar wall than in the muscle; in hindgut the terminals with immunoreactive granules are associated with the muscle net below the circular muscle. Hindgut responded to allatostatins I and IV with a dose‐dependent decrease in amplitude and frequency of contraction that was reversible, with the threshold concentration for response between 10−8 and 10−7 M. In contrast, pulsatile organ muscle showed no such change with either allatostatin at 10−7–10−4 M. However, both organs responded to proctolin with increased amplitude and frequency of contractions. Allatostatins I and IV inhibited the proctolin‐induced increase of hindgut contraction, whereas no such effect was seen in antennal pulsatile organ muscle. Extract of antennal pulsatile organ muscle showed proctolin‐like bioactivity that comigrated with authentic proctolin on three sequential HPLC systems. © 1993 Wiley‐Liss, Inc.
Biogenic amines in the two‐spotted spider mite
Authors: Sparks Thomas C. , Skomp John R. , Babcock Jon , Geng Chaoxian 
Published: February 2005

AbstractWhole body extracts of the two‐spotted spider mite (Tetranychus urticae Koch) were analyzed using a 16‐channel electrochemical array high performance liquid chromatography (HPLC)‐based detection system that allows the simultaneous isolation and identification of a variety of biogenic amines. The spider mite extracts were found to contain the biogenic amines octopamine, dopamine, and 5‐hydroxytryptamine (5‐HT), as well as several precursors and metabolites including tyrosine, tyramine, tryptophan, and N‐acetyl octopamine. Differences in the levels of biogenic amines were observed between eggs and the adult stages and between males and females. This is the first direct determination of biogenic amines in the Tetranychidae and the first demonstration of 5‐HT in any mite species. © 1994 Wiley‐Liss, Inc.