bluuebunny/crossref_metadata_2025 huggingface dataset:
Depressant insect selective neurotoxins from scorpion venom: Chemistry, action, and gene cloning
Authors: Zlotkin Eliahu , Gurevitz Michael , Fowler Elisabeth , Adams Michael E.
Published: February 2005

The present study examines the similarity in the symptoms and binding properties between the depressant and excitatory insect‐selective neurotoxins, derived from scorpion venom. A comparison of their primary structures and neuromuscular effects is presented. A new depressant toxin (LqhlT2) was purified from the venom of the scorpion Leiurus quinquestriatus hebraeus. The effects of this toxin on a prepupal housefly neuromuscular preparation mimic its effects on the intact insect, i.e, a brief period of repetitive bursts of regular junction potentials (JPs) is followed by reduced amplitude JPs ending with a block of the neuromuscular transmission. “Loose” patch clamp recordings indicate that the repetitive activity has a presynaptic origin (the motor nerve) and resembles the effect of the excitatory toxin AalT. The final synaptic block is supposed to be the end result of neuronal membrane depolarization. Such an effect is not caused by an excitatory toxin, which induces long ‘trains’ of repetitive firing. The amino acid sequences of three depressant toxins were determined by automatic Edman degradation indicating a high degree of sequence homology. This conservation differs from those of other groups of scorpion toxins. The opposing pharmacological effects of depressant toxins are discussed in light of the above neuromuscular effects and sequence analysis. A genetic approach in the study of the structure‐function relationships of the depressant toxins was initiated by isolating cDNA clones encoding the LqhiT2 and BjlT2 toxins. Their sequence analysis revealed the precursor form of these toxins: A 21 amino acid residue signal peptide followed by a 61 amino acid region of the mature toxin, and three additional amino acids at the carboxy terminus. © 1993 Wiley‐Liss, Inc.
Peptidergic innervation and endocrine cells of insect midgut
Authors: Žitňan Dušan , Šauman Ivo , Sehnal František
Published: February 2005

Antibody against FMRFamide reacts with the stomatogastric innervation and with the midgut endocrine cells in the representatives of most insect orders. The innervation was not revealed in Homoptera, Heteroptera, and Hymenoptera, and the endocrine cells were not recognized in aphids. Other insects exhibited FMRF‐amide positive endocrine cells of both open and closed types. The cells are mostly single, rarely grouped, and are distributed unequally in different midgut regions; some of the cells project cytoplasmic extensions indicative of a paracrine function. Investigations on Galleria revealed that the gut innervation persists during midgut reconstruction in the course of metamorphosis. The endocrine cells are sloughed off into the new gut lumen, but there they maintain their antigenic properties until a new population of endocrine cells becomes detectable.

Antisera to most mammalian gastroenteropancreatic peptides react specifically with the innervation and/or the endocrine cells of insect midgut; only antisera to bombesin, neurotensin, secretin, motilin, and insulin failed to react. All insects seem to contain antigens that can be detected with antisera to pancreatic polypeptide, FMRFamide, enkephalins, and vasopressins. Stomatogastric innervation and the endocrine cells of some lepidopterans also possess allatotropinand diuretic hormone‐like antigens; stomatogastric ganglia, in particular, a prothoracicotropic hormone‐like antigen. © 1993 Wiley‐Liss, Inc.
Characteristics of Locusta migratoria diuretic hormone
Authors: Lehmberg Elisabeth , Schooley David A. , Ferenz Hans‐J. , Applebaum Shalom W.
Published: February 2005

Locusta migratoria diuretic hormone (Lom‐DH) is a linear 46 amino acid peptide, amidated at the C‐terminus. The purified native hormone and synthetic peptide similarly stimulate the secretion of cAMP by isolated Malpighian tubules in vitro in a dose‐dependent manner. The degree of stimulated fluid secretion in the isolated Malpighian tubule assay is similar for the native and synthetic hormone. Based on ELISA assay, Lom‐DH is mainly found in the storage lobes of the corpora cardiaca (∼ 12 pmol per gland pair) and to a small extent in the brain. Marginal amounts can be detected in the hemolymph. No detectable amounts were found in the glandular lobes of the corpora cardiaca or in the corpora allata or subesophageal ganglion. © 1993 Wiley‐Liss, Inc.
Leads for insect neuropeptide mimetic development
Authors: Nachman Ronald J. , Holman G. Mark , Haddon William F.
Published: February 2005

Insect neuropeptides mediate a number of physiological processes critical for insect survival. The numerous neuropeptide sequences that have been reported present an opportunity to decipher the chemical and conformational requirements for neuropeptide‐receptor interactions. Chemical and conformational requirements for activity represent a “template” from which agonist/antagonist peptide mimetics, with the potential to disrupt critical insect processes, can be developed. Information on structural requirements is presented for three neuropeptide families: the sulfakinins, pyrokinins, and leucokinin/achetakinins, including active core size, important side chains, peptide superagonists, and new data on pseudopeptide modification of the N‐ and C‐terminal regions. Members of these peptide families have been associated with a variety of physiological activities such as myotropism, pheromonotropism, diapause induction, and diuresis in a number of insects. Spectroscopic data coupled with computer molecular dynamics/graphics studies on conformationally restricted analogs of insect neuropeptides reveal information on the active conformation adopted at the receptor site. Routes to development of peptide‐mimetics from neuropeptide templates are discussed. © 1993 Wiley‐Liss, Inc.
Expression of hornet genes encoding venom allergen antigen 5 in insects
Authors: Tomalski Michael D. , King Te Piao , Miller Lois K.
Published: February 2005

Antigen 5, also known as Dol m V, is a major allergen found in the venom of the baldfaced hornet, Dolichovespula maculata. We have inserted the f10 and f17 cDNAs, which encode hornet antigen 5 (HA5) forms 2 (Dol m; VB) and 3 (Dol m VA), respectively, into the genome of the baculovirus, AcMNPV, to produce the recombinant baculovirus gene expression vectors, vEV‐HA5f10 and vEV‐HA5f17. Insect cells infected with either vEV‐HA5f10 or vEV‐HA5f17 produce and secrete a novel protein with an electrophoretic mobility which is similar if not identical to authentic mature Dol m V. The gene products also react specifically with a polyclonal antiserum raised to Dol m VB as expected. Dol m V gene products were not acutely toxic when injected into insect larvae. However, infection of fifth instar larvae with vEV‐HA5f17 resulted in premature melanization of the larvae and lower weight gain than infection with control virus. Thus, the Dol m V gene product has a subtle, possibly cytotoxic or biochemical effect on insects. The expression systems may prove useful in further structural and functional characterization of these proteins. © 1993 Wiley‐Liss, Inc.
Sex pheromones: Achievements in monitoring and mating disruption of cotton pests in Israel
Authors: Kehat Moshe , Dunkelblum Ezra
Published: February 2005

Israeli contributions to the development of monitoring and mating suppression systems for cotton pests via the use of sex pheromones are described. These include identification of pheromones, development of dispensers and traps, assessment of pheromone traps as a monitoring device, and the use of pheromones for mating disruption. In Spodoptera littoralis, the minor component, Z9,E12–14:Ac, in addition to the major component, Z9,E11–14:Ac, was found to be essential for attracting males. The pheromonal components of Helicoverpa armigera were identified and only two, Z11–16:Ald and Z9–16:Ald, were found to be of importance for attracting males. In Heliothis peltigera two major pheromonal components, Z11–16:Ald and Z9–14:Ald, were identified and a species‐specific lure was developed. Two essential components, E10,E12–16:Ald and Z11–16:Ald, were detected in Earias insulana and proved to be effective in the field. The importance of the dispenser for attracting males was investigated. The efficiency of an Israeli septa was greater than that of other septa presently in use in the U.S.A for attracting H. zea or H. virescens. It was also shown that a more suitable dispenser enables the use of a smaller and easier to handle trap. Different types of traps used in Israel over the years are described. The modern funnel traps that are in wide use today throughout the world have almost the same design as the funnel traps developed in Israel long ago. Generally, there is a positive relation between captures of males in traps and the actual population in the field. However, peak capture of males in traps is somewhat delayed as compared with the peak of females in the field, and corresponds more to the egg peak. Trials carried out in Israel to test a hand‐applied polymeric aerosol formulation containing the major sex pheromone component of S. littoralis gave very promising results. Satisfactory mating disruption by hand application of ShinEtsu ropes was obtained for Pectinophora gossypiella and H. armigera. The pink bollworm P. gossypiella is commercially controlled today in Israel by NoMate or ShinEtsu ropes. Twist‐tie formulations for combined mating disruption of both pink bollworm and E. insulana are also being tested. © 1993 Wiley‐Liss, Inc.
Photostabilization of pesticides by clays and chromophores
Authors: Margulies Leon , Rozen Harel , Stern Theodor , Rytwo Giora , Rubin Baruch , Ruzo Luis O. , Nir Shlomo , Cohen Ephraim
Published: February 2005

Mechanisms for the photostabilization of pesticides by the use of clays and chromophores are described. The main mechanisms include energy transfer and steric hindrance, whereas the importance of mechanisms such as light scattering and hypsochromic shift is marginal. As an example for energy transfer we describe a procedure where the potent and safe but photolabile insecticide bioresmethrin (BR) is coadsorbed on montmorillonite together with the organic cation methyl green (MG). It is shown that the effective photostabilization of BR occurs by the process of energy transfer, which depends on the matching of energy levels of donor (BR) and acceptor (MG) chromophores, on the distance between them and on their relative orientations. The methods for studying the intermolecular interaction between two coadsorbed organic molecules include Fourier‐transform infrared (FTIR) and 13C solid state magic angle spinning nuclear magnetic resonance (MAS‐NMR) spectroscopies. Energy transfer processes can also occur from the pesticide to the clay. The presence of transition metal ions in the clay can make it an efficient energy or charge acceptor. Such a mechanism was utilized in the photostabilization of the insecticide tetrahydro‐2‐(nitromethylene)‐2H‐1, 3‐thiazine (NMH). In the latter case, improved photostabilization was achieved by an addition of the cationic dye acriflavine (AF). Steric hindrance: here the clay introduces a stereochemical factor in preventing or slowing down certain photochemical reactions. An example is the photostabilization of the dinitroaniline herbicide trifluralin (TF). The energy transfer approach was also shown to be effective in the photostabilization of microbial insecticides, such as the Bacillus thuringiensis (B.t.) toxin. Photoprotection was achieved by adsorption of cationic chromophores such as AF, MG and rhodamin B to B.t. © 1993 Wiley‐Liss, Inc.
Penetration of pesticides and industrial organics deep into soil and into groundwater
Authors: Muszkat Lea , Lahav Doron , Ronen Daniel , Magaritz Mordeckai
Published: February 2005

We report on two different cases of penetration of organic pollutants deep into the soil and into groundwater. In one event a point source of pollution from a pesticides plant has been studied by a long‐term follow‐up of a polluted well close to the plant. A typical pattern of pollution has been observed in this well, which was studied for four years. There was a similar organic pollution pattern in soil samples close to the plant. The second case involved an agricultural area long irrigated with effluents. In this area there was an accumulation of organic pollutants deep in the soil (5–20 m depth) and in the groundwater. The mobilizing effect of effluents in promoting the penetration of micropollutants into the depth of soil has been shown. This effect presumably is due to the presence of surface active components. The reported results demonstrate the facile transport of a wide range of xenobiotic organics deep into the soil and into deep groundwater, and advises caution in the use of reclaimed wastewaters for irrigation. © 1993 Wiley‐Liss, Inc.
Second messengers mediating the effects of testis ecdysiotropin in testes of the gypsy moth, Lymantria dispar
Authors: Loeb Marcia J. , Gelman Dale B. , Bell Robert A.
Published: February 2005

Exposure of larval and pupal testes of Lymantria dispar to diacyl glycerol mimics, phorbol, 12‐myristate, 13‐acetate, and 11, 12 dibutyryl phorbol ester, induced or augmented synthesis of immunodetectable ecdysteroids. The non‐esterified analog, 4α‐phorbol, had little effect. H‐7, a protein kinase C inhibitor, inhibited ecdysteroid synthesis. When testis ecdysiotropin and phorbol esters were administered together at the maximum effective dose of each, steroidogenesis was further enhanced. Therefore, diacyl glycerol may be a second messenger for testis ecdysiotropin in testes. In addition, testis ecdysiotropin induced a rapid rise and fall in cAMP titers in both larval and pupal testes. The cyclic AMP analog, dibutyryl cyclic AMP, induced ecdysteroid synthesis in larval testes, but had little steroidogenic effect in pupal testis sheaths. However, dibutyryl cyclic AMP inhibited the steroidogenic effect of testis ecdysiotropin in larval as well as pupal testes. Cyclic AMP may act to modulate the effects of testis ecdysiotropin in inducing ecdysteroid synthesis by testes of L. dispar. © 1993 Wiley‐Liss, Inc.
Analysis of lipids in the salivary glands of Amblyomma americanum (L.): Detection of a high level of arachidonic acid
Authors: Shipley Michael M. , Dillwith Jack W. , Sauer John R. , Essenberg Richard C. , Howard Ralph W.
Published: February 2005

Analysis of lipids in salivary glands of the lone star tick, Amblyomma americanum, demonstrated that arachidonic acid (20:4, n‐6) comprises 8% of all fatty acids identified by gas chromatography. The occurrence of arachidonic acid and other C20 polyunsaturated fatty acids in tick salivary glands was confirmed by gas chromatography‐mass spectrometry. Arachidonate is located entirely in the phospholipid fraction and is associated exclusively with phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Salivary glands stored and frozen for several months had a similar lipid composition as freshly dissected salivary glands, with the exception of a small amount of free arachidonic acid and an increase in lysophosphatidylcholine. Incubation of salivary gland homogenates with snake venom phospholipase A2 showed that most saturated fatty acids are esterified in the sn‐1 position of PC and PE, with the unsaturated fatty acids in the sn‐2 position. Approximately 75% of arachidonic acid is in the sn‐2 position of PC and PE, adding support to the hypothesis that arachidonic acid is released into the cytoplasm after activation of a phospholipase A2 for subsequent metabolism to prostaglandins and/or other eicosanoids. © 1993 Wiley‐Liss, Inc.
Metabolism of [3H]‐ecdysone in embryos and larvae of the tick Ornithodoros moubata
Authors: Dotson Ellen M. , Connat Jean‐Louis , Diehl Peter A.
Published: February 2005

The fate of [3H]‐ecdysone ([3H]‐E) was investigated in hanging drop cultures of embryos and larvae of the tick Ornithodoros moubata using HPLC. The hormone was metabolized more slowly during described periods of increasing endogenous ecdysteroid (ES) titers than during periods of low titers except for young embryos. Three different classes of metabolites were produced: (1) apolar products (AP) corresponding to C‐22 fatty acid ester conjugates of E and, in some cases, of 20‐hydroxyecdysone (20E), (2) unidentified polar products (PP) more polar than E, one peak of which had the same retention times as 20,26‐dihydroxyecdysone, and finally, (3) 20E verified by comigration of cold standards on RP‐18 and silica columns. Hydroxylation of E to 20E first became evident in cultures of 2 day old embryos and was present in all cultures of older animals. Highest production of free 20E occurred during increasing endogenous ES titers in embryos and during the ES peak in larvae. Conjugation of E to AP occurred in all stages investigated, but was more pronounced during periods of low endogenous ES titers, and may correspond to a detoxification mechanism. In contrast, PP were produced during high 20E production in embryos and during periods of high and decreasing endogenous titers in larvae. © 1993 Wiley‐Liss, Inc.
Neosurugatoxin blocks an α‐bungarotoxin‐sensitive neuronal nicotinic acetylcholine receptor
Authors: Bai Donglin , Sattelle David B.
Published: February 2005

Neosurugatoxin (NSTX), a neurotoxin isolated from the Japanese ivory mollusc Babylonia japonica, is a potent neuronal nicotinic acetylcholine receptor (nAChR) antagonist. Hitherto, NSTX has been found to block only neuronal nAChRs that are insensitive to α‐Bgt. Here, we report for the first time that NSTX blocks an α‐Bgt‐sensitive nAChR on an identified insect motor neurone. Bath‐applied NSTX at a concentration of 10 nM and above reversibly blocks the nicotine‐induced depolarizations recorded from the cockroach (Periplaneta americana) fast coxal depressor motor neurone (Df) and is without effect on GABA‐induced responses detected on the same cell. NSTX is among the most potent blockers tested to date on nAChRs of motor neurone Df. © 1993 Wiley‐Liss, Inc.
On the control of ecdysone biosynthesis by the central nervous system of blowfly larvae
Authors: Budd Evelyn , Käuser Gerd , Koolman Jan
Published: February 2005

Ecdysone was found to be the major secreted steroid of ring glands dissected from blowfly larvae and incubated in vitro. Other secretory products such as 3‐dehydroecdysone and 20‐deoxy‐makisterone A could not be detected when the glands were labelled with tritiated cholesterol. Ecdysone synthesis and secretion were found to be tightly coupled. The highest rate of secretion was observed a few hours before pupariation. In vitro, the rate of ecdysone secretion by ring glands was affected significantly by coincubation with the central nervous system (CNS). Modulating effects from the CNS to the gland were mediated both by culture medium and by nerve connections. Distinct parts of the CNS revealed multiple and partially opposite effects on ecdysone secretion, suggesting a more complex control than had been anticipated. Multiple neural control systems appear to be involved. Moreover, the observed effects changed with development during the second half of the third instar, reflecting a significant plasticity of neural control. © 1993 Wiley‐Liss, Inc.
Ecdysone oxidase and 3‐oxoecdysteroid reductases in Manduca sexta: Developmental changes and tissue distribution
Authors: Weirich Gunter F. , Feldlaufer Mark F. , Svoboda James A.
Published: February 2005

The activities of ecdysone oxidase (EO), 3‐oxoecdysteroid 3α‐reductase (3α‐R), and 3‐oxoecdysteroid 3β‐reductase (3β‐R) were determined for epidermis, hemolymph, and fat body of wandering fifth instar Manduca sexta larvae and for midguts of various developmental stages between 3 days after the last larval and 14 days after the pupal ecdysis. The larval midgut was the only organ showing substantial specific activities of EO and 3α‐R, and both increased up to the seventh day after ecdysis. Hemolymph and fat body had only moderate to high 3β‐R and low EO activites, and the epidermis did not contain significant activity of any of the enzymes. On the ninth day after the last larval ecdysis the larval midgut epithelium was replaced by a new pupal midgut epithelium. After this event only 3β‐R was restored to high activities, whereas EO and 3α‐R showed only low to marginal activities. It is concluded that only the larval midgut has a role in the inactivation of ecdysteroids by 3‐epimerization. © 1993 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Changes in the size of corpora allata, in the juvenile hormone III titer in the hemolymph, and in the protein content of terminal oocytes throughout the first gonadotropic cycle in Aiolopus thalassinus (Insecta: Orthoptera: Acrididae)
Authors: Schmidt Gerhard H. , Othman Kamal S. A.
Published: February 2005

In Aiolopus thalassinus (Fabr.), the changes in the volume of the corpora allata (CA), in the concentration of juvenile hormone III (JH III) in the hemolymph, and in protein content in the terminal (t) oocytes were studied during the first gonadotropic cycle. These parameters could be better related to the volume of t‐oocytes than to age after emergence. The JH III titer curve was maximum (2.9 pmol/10 μl) at an oocyte volume of 1.2 mm3. Before oviposition (days 10–16) the JH III titer decreased to 0.65 pmol/10 μl hemolyph. The increase in JH III titer reflected a period of high protein storage in the t‐oocytes. The largest volume of the CA was reached at the beginning of yolk storage in the t‐oocytes. The highest JH III titer did not correspond with the largest volume of CA, which occurred much earlier. © 1993 Wiley‐Liss, Inc.
Growth and development of Cardiochiles nigriceps viereck (hymenoptera, braconidae) larvae and their synchronization with some changes of the hemolymph composition of their host, Heliothis virescens (F.) (Lepidoptera, Noctuidae)
Authors: Pennacchio Francesco , Vinson S. Bradleigh , Tremblay Ermenegildo
Published: February 2005

Larval development of the parasitoid Cardiochiles nigriceps Viereck occurs in the last instar larva of its host, Heliothis virescens (F.). This allows the parasitoid to exploit the nutritional increase in the biosynthetic activity occurring in the host in preparation for metamorphosis. To understand the biochemical basis of this host parasitoid developmental synchrony, we undertook host ligation studies and analyzed host hemolymph for proteins and glycerol esters. Parasitization affected the biochemical profile of the host. The hemolymph protein concentration of parasitized last instar H. virescens larvae increased through time, whereas unparasitized (control) larvae were characterized by a decrease in the protein titer when they reached the prepupal stage. The effect of parasitism on glyceride titers of host hemolymph was not as pronounced as the effect on proteins. Ligation conducted on 5th instar hosts, which were parasitized as 4th instars, affected parasitoid development in a time‐dependent way. The percentage of successfully developing C. nigriceps larvae increased with the increase of the time interval between parasitization and ligation. Ligation performed before day 2 of the 5th larval instar of H. virescens completely inhibited parasitoid development. Ligations that disrupted parasitoid developmentwere associated with a low host hernolymph protein concentration. Parasitoid development was successful when hernolymph protein titer was high, as occurred when ligations were performed after day 3 of the 5th host instar in both control and parasitized larvae. Ligations in both situations resulted in a slight increase in glyceride titers. The results suggest that host proteins and/or some factor(s) associated with them may play a role in parasitoid growth and development. © 1993 Wiley‐Liss, Inc.
Control of pheromone biosynthesis in mated redbanded leafroller moths
Authors: Jurenka Russell A. , Fabriás Gemma , Ramaswamy Sonny , Roelofs Wendell L.
Published: February 2005

Mating in the redbanded leafroller moth, Argyrotaenia velutinana, causes a permanent decline in pheromone titers. Three hours following the termination of mating, phermone titers were significantly decreased from premating levels, and titers remained low for at least four days after mating. Pheromone titers were similar in females that had been decapitated or mated for twenty‐four hours. In the redbanded leafroller moth, two peptides control pheromone production. The pheromone biosynthesis activating neuropeptide is produced in the brain and the pheromonotropic bursa peptide is produced in the corpus bursae. Both peptides stimulated pheromone biosynthesis in mated females and extracts prepared from brains and bursae of mated females contained pheromonotropic activity. However, severing the ventral nerve cord before mating prevented the decline in pheromone titer that occurred in mated females. Hemolymph collected during scotophase from mated females did not have pheromonotropic activity, whereas hemolymph collected during scotophase from virgin females contained activity. These results indicate that mating produces a signal sent by the ventral nerve cord to the brain to stop the release of pheromone biosynthesis activating neuropeptide. © 1993 Wiley‐Liss, Inc.
Expression of a parasitism‐specific protein in lepidopteran hosts of Chelonus sp.
Authors: Soldevila Ana I. , Jones Davy
Published: February 2005

The hemolymph of each noctuid species successfully parasitized by Chelonus near curvimaculatus possessed a parasitism‐specific protein (PSP) previously identified in host T. ni (Insect Biochem. 19:445; 21:845). Expression of PSP occurred in a stage‐specific manner in the stadium during which the host undergoes precocious metamorphosis. The appearance of the protein was not due to nutritional stress associated with parasitism of hosts, since starved nonparasitized larvae did not produce the protein, or to low juvenile hormone titers occurring in precociously metamorphosing hosts, but rather was dependent on the presence of the endoparasite larva. Results of in vivo incorporation experiments with [35S]‐methionine showed that synthesis and subsequent appearance of the protein in the hemolymph of parasitized hosts was abrogated by prior surgical removal of endoparasite. Immunoprecipitation analysis of proteins from C. near curvimaculatus larvae cultured in vitro using antibodies specific to PSP indicated that the source of the protein was the endoparasite. Synthesis of PSP by the endoparasitic larvae with its subsequent secretion into the hemocoel of hosts was specific to the advanced stages of parasite development prior to its egression from the host. © 1993 Wiley‐Liss, Inc.
Phospholipase A2 activity in the fat body of the tobacco hornworm Manduca sexta
Authors: Uscian John M. , Stanley‐Samuelson David W.
Published: February 2005

We report on phospholipase A2 (PLA2) activity in homogenates prepared from fat bodies of the tobacco hornworm Manduca sexta. PLA2 activity is responsible for hydrolyzing fatty acids from the sn‐2 position of phospholipids. The rate of hydrolysis increased with increasing homogenate protein concentration up to ∼︁ 320 μg protein/ml reaction volume. Higher protein concentrations did not appreciably increase the rate of PLA2 activity. As seen in some, but not all PLA2s from mammalian sources, hydrolyzing activity increased linearly with time. The fat body activity was sensitive to pH (optimal activity at pH 8–9) and temperature (optimal activity at ∼︁40°C). The activity was associated with fat body rather than hemolymph, because no activity was detected in cell‐free serum. The fat body PLA2 activity differs from the majority of PLA2s with respect to calcium requirements. Whereas most PLA2s are calcium‐independent. A few others are known to require submicromolar calcium concentrations. The fat body activity appears to be calcium independent. These data show that a PLA2 activity that can hydrolyze arachidonic acid from the sn‐2 position of phospholipids is associated with the tobacco hornworm fat body. The biological significance of this activity relates to biosynthesis of eicosanoids. Pharmacological inhibition of PLA2 impairs the ability of this insect to respond to bacterial infections. Since the impairment can be reversed by treatment with exogenous arachidonic acid, the PLA2 activity may be an important step in eicosanoid biosynthesis. © 1993 Wiley‐Liss, Inc.
Tissue‐specific changes in polyamine levels of neural tissue and fat body in adult crickets
Authors: Strambi Colette , Faure Philippe , Renucci Marielle , Charpin Pierre , Augier Roger , Tirard Alain , Strambi Alain
Published: February 2005

The three major polyamines—putrescine, spermidine, and spermine—were studied and changes of their levels were examined in extracts of cerebral ganglia and fat body from adult Acheta domesticus. In nervous tissue, only spermidine and spermine were present and spermine was two‐ to three‐fold more abundant than spermidine. The polyamine levels were high up to day 3, decreased on day 4, and then remained relatively unchanged up to day 10. The spermidine/spermine ratios decreased during the imaginal life. Higher spermidine titres were observed in the neural tissue of egg‐laying females compared to virgin females. In the fat body, putrescine was detected together with spermidine and spermine. Spermidine and spermine levels were two‐fold higher than putrescine. Fat body of virgin females contained two times more polyamines than male fat body. Low at emergence, spermidine and spermine concentrations peaked on days 2–3 only in females, and egg‐laying was characterized by an increase of putrescine and spermidine titres. Starvation did not change polyamine contents, implying homeostatic regulation of the intracellular polyamine metabolism. These data showing tissue specific changes in polyamine levels during the imaginal life of Acheta domesticus point to the physiological importance of polyamines as possible intracellular regulators during adult insect development. © 1993 Wiley‐Liss, Inc.
Age and tissue‐dependent changes of ornithine decarboxylase and s‐adenosylmethionine decarboxylase activities in neural tissue and fat body of adult crickets
Authors: Cayre Myriam , Tirard Alain , Charpin Pierre , Augier Roger , Strambi Colette , Strambi Alain
Published: February 2005

The activities of ornithine decarboxylase and S‐adenosylmethionine decarboxylase, two key enzymes in polyamine metabolism, were determined during the first 10 days of imaginal life in the nervous tissue and the fat body of the adult cricket Acheta domesticus. The kinetic constants of the two enzymes were also determined in both tissues. Both decarboxylases presented a higher activity in fat body than in nervous tissue. In nervous tissue, the activity of the two enzymes peaked at 16 h postemergence, then slowly decreased up to day 3–4. By contrast, the enzymatic activities in fat body, low at emergence, strongly increased on day 2. Thereafter, whereas ornithine decarboxylase activity remained rather high. S‐adenosyl‐methionine decarboxylase activity dropped back to emergence levels by day 10. These results, examined in light of the temporal alterations of polyamine levels observed in the two tissues, demonstrate synchronous variations between polyamine contents and the enzymes involved in their biosynthesis. © 1993 Wiley‐Liss, Inc.
Actions of acromelic acid on nervous system l‐glutamate receptors
Authors: Sattelle David B. , Sepúlveda Maria‐Isabel , Shinozaki Haruhiko , Ishida Michiko
Published: February 2005

Acromelic acid, a naturally occurring kainoid, isolated from the mushroom Clitocybe acromelalga, is a weak displacer of [3H]L‐glutamate binding to cockroach (Periplaneta americana) nerve cord membranes. Acromelic acid (1 mM) displaces ∼︁60% of specifically bound [3H]L‐glutamate. When applied by bath perfusion to the cell body membrane of the cockroach fast coxal depressor motor neurone, acromelic acid generated slow, prolonged, dose‐dependent depolarizations at concentrations of 0.3 μM and above. Thus acromelic acid is among the most potent of the excitatory amino acids tested to date on insect neurones. © 1994 Wiley‐Liss, Inc.
Midgut proteinase activities of three keratinolytic larvae, Hofmannophila pseudospretella, Tineola bisselliella, and Anthrenocerus australis, and the effect of proteinase inhibitors on proteolysis
Authors: Christeller John T. , Markwick Ngaire P. , Burgess Elisabeth P. J.
Published: February 2005

The midgut proteinase activities were characterized from the keratinolytic larvae of two lepidopterans, Hofmannophila pseudospretella (Stainton) (Oecophoridae) and Tineola bisselliella (Hummel) (Tineidae), and one coleopteran, Anthrenocerus australis (Hope) (Dermestidae). The major endopeptidase activities, characterized using specific enzyme inhibitors, were serine proteinases with hydrolytic activity against N‐benzoyl‐DL‐arginine‐p‐nitroanilide and against N‐succinyl‐L‐alanyl‐L‐alanyl‐L‐prolyl‐L‐leucine‐p‐nitroanilide. No significant levels of metalloendopeptidase or cysteine endopeptidase activities were detected. Aminopeptidase activity was present in all larvae. The enzyme levels and properties of the two moth larvae were similar to each other and to those of phytophagous lepidopteran larvae but different from those of the beetle larva. Whereas only a limited number of serine proteinase inhibitors inhibited the midgut proteolysis of the lepidopteran larvae, most inhibitors inhibited the midgut proteolysis of the beetle larva. © 1994 Wiley‐Liss, Inc.
Pheromonotropic and pheromonostatic activity in moths
Authors: Ramaswamy Sonny B. , Mbata George N. , Cohen Nancy E. , Moore Alfred , Cox Nancy M.
Published: February 2005

Pheromone biosynthesis in many species of moths requires a pheromonotropic neurosecretion, the pheromone biosynthesis activating neuropeptide (PBAN), from the brain‐subesophageal ganglion‐corpora cardiaca complex. Some investigators suggest that PBAN is released into the hemolymph and acts directly on sex pheromone glands (SPG) via a Ca++/calmodulin‐dependent adenylate cyclase. Others suggest, however, that PBAN acts via octopamine that is released by nerves from the terminal abdominal ganglion innervating the SPG. These findings suggest that there are controversies on the mode of action of PBAN and other pheromonotropic factors, sometimes even within the same species.

Mating in many insects results in temporary or permanent suppression of pheromone production and/or receptivity. Such a suppression may result from physical blockage of the gonopore or deposition of pheromonostatic factor(s) by the male during copulation that result in suppressed pheromone production and/or receptivity in females either directly or by a primer effect. In several species of insects, including moths, a pheromonostatic factor is transferred in the seminal fluid of males. Similar to the controversies associated with the pheromonotropic activity of PBAN, sometimes even within the same species, there appear to be controversies in pheromonostasis in heliothines as well.

This paper reviews these conflicting findings and presents some data on pheromonostatic and pheromonotropic activity in Heliothis virescens that support and conflict with current information, raising further questions. Answers to some of the questions are partly available; however, they remain to be answered unequivocally. © 1994 Wiley‐Liss, Inc.
Patterns of biosynthesis and accumulation of hydrocarbons and contact sex pheromone in the female german cockroach, Blattella germanica
Authors: Schal Coby , Gu Xiaoping , Burns Edina L. , Blomquist Gary J.
Published: February 2005

De novo synthesis of contact female sex pheromone and hydrocarbons in Blattella germanica was examined using short in vivo incubations. Accumulation of pheromone on the epicuticular surface and the internal pheromone titer were related to age‐specific changes in hydrocarbon synthesis and accumulation in normal and allatectomized females. The incorporation of radiolabel from [1‐14C]propionate into the cuticular methyl ketone pheromone fraction was positively related to corpora allata activity during two gonotrophic cycles. During peak pheromone production the total internal lipid fraction contained greater titers of pheromone than the cuticular surface, and it too exhibited a cycle internally, preceding the rise in external pheromone. This suggests that synthesis and accumulation of pheromone internally are followed by transport of pheromone to the epicuticular surface where it accumulates. Radiolabel was incorporated efficiently into both cuticular and internal hydrocarbons after the imaginal molt and until the peak of pheromone synthesis, but it declined to lower levels before ovulation and throughout pregnancy. The internal hydrocarbon titer decreased 58% after oviposition, suggesting deposition in the egg case. It remained relatively unchanged during pregnancy and increased again during the second gonotrophic cycle. In allatectomized females, hydrocarbon synthesis was reduced relative to control females until oviposition in the latter. However, subsequent rates of hydrocarbon synthesis in allatectomized females (without oothecae) exceeded the rates in sham‐operated females (with oothecae). In the absence of ovarian uptake of hydrocarbons, the internal titer increased without the decline found in control females at oviposition. As internal hydrocarbons increased, so did cuticular hydrocarbons and both internal and cuticular methyl ketone pheromones. These patterns corresponded well with feeding patterns in sham‐operated and allatectomized females, suggesting that pheromone production is normally regulated by stage‐specific feeding‐induced hydrocarbon synthesis (precursor accumulation internally) and juvenile hormoneinduced conversion of hydrocarbon to pheromone. They also suggest that both the cuticle and the ovaries might be target sites for hydrocarbon and possibly methyl ketone deposition. © 1994 Wiley‐Liss, Inc.
Biosynthesis of sorbic acid in aphids: An investigation into symbiont involvement and potential relationship with aphid pigments
Authors: Walters Frederick S. , Mullin Christopher A. , Gildow Frederick E.
Published: February 2005

Studies were undertaken to determine the role of symbionts and UV exposure in biosynthesis of the aphid‐specific polyketides, sorbic acid and quinone pigments. Injection of adult potato aphids, Macrosiphum euphorbiae (Thomas), with the antibiotic rifampicin did not alter the level of sorbic or myristic acid in triglycerides of resultant progeny; pigmentation was also unaffected. However, antibiotic injection did produce marked physiological effects; progeny from injected aphids were smaller, slower to mature, and not fecund. Light microscopy confirmed that only 8% of rifampicin‐treated aphids contained mycetocytes; thus, symbiont involvement in the production of this unusual UV‐quenching short chain fatty acid is not supported. Following multigenerational exposure to long wavelength UV light, no substantial changes in sorbic acid content were detected in the potato aphid or the oleander aphid, Aphis nerii Fonscolombe. Pigments from UV‐exposed oleander aphids had a peak absorbance at 390 nm, 70 nm lower than unexposed aphids. This suggests a photo‐protective role for the pigments of the sunlight‐inhabiting A. nerii; by contrast, no changes were observed in pigments of M. euphorbiae which usually feeds in the shade. Injection of adult potato aphids with sodium [1‐14C]‐acetate rapidly labeled both sorbic acid and pigments, particularly among the latter a yellow pigment which co‐chromatographed with the dominant C15 yellow pigment of the oleander aphid. These data support the hypothesis that aphid C30 pigments are built up by coupling of “monomeric type” C15 pigments. Although aphid and not symbiont enzymes appear to synthesize these acetogenins, a possible biosynthetic link between sorbic acid and aphid pigments requires further clarification. © 1994 Wiley‐Liss, Inc.
Cyclodiene resistance at the insect GABA receptor/chloride channel complex confers broad cross resistance to convulsants and experimental phenylpyrazole insecticides
Authors: Bloomquist J. R.
Published: February 2005

This study investigated the pharmacological profile of cyclodiene resistance in Drosophila melanogaster and the mode of action of a phenylpyrazole insecticide, JKU 0422. Toxicological studies were performed with a sucrose bait assay containing the synergist piperonyl butoxide. The Maryland strain of D. melanogaster was resistant to dieldrin, lindane, picrotoxinin, TBPS, p‐CN‐TBOB, and JKU 0422. In contrast, this strain was susceptible to cypermethrin and the avermectins MK‐243, abamectin, and abamectin 8,9‐oxide. Neurophysiological studies showed that both TBPS and JKU 0422 reversed the inhibitory action of GABA in central nerve preparations from susceptible D. melanogaster. However, the response to these compounds was attenuated in nerve preparations from the resistant Maryland strain, which indicated that the resistance was expressed at the level of the nerve. Topical toxicity bioassays with JKU 0422 on susceptible (CSMA) and cyclodiene‐resistant (LPP) strains of German cockroach revealed a resistance ratio of 553‐fold for this compound. These studies demonstrate that cyclodiene resistance in D. melanogaster confers broad cross resistance toward compounds thought to block the GABA‐gated chloride channel in a manner similar to the cyclodienes. Moreover, the cross resistance extends to JKU 0422, and resistance to this compound is also present in a strain of cyclodiene‐resistant German cockroach. These toxicological results, along with the neurophysiological studies, confirm that JKU 0422 has a mode of action that is similar to the cyclodienes and TBPS. These findings suggest that the introduction and use of new chloride channel antagonists as insecticides should be managed carefully in order to prevent the rapid development of resistance in the field. © 1994 Wiley‐Liss, Inc.
Sources of possible host regulatory factors in Cardiochiles nigriceps (hymenoptera: Braconidae)
Authors: Vinson S. Bradleigh , Mourad Ahmed Kamal , Sebesta Deborah K.
Published: February 2005

Both larvae and teratocytes liberated upon hatching from the eggs of the endoparasitoid Cardiochiles nigriceps Viereck were found to release proteins into their surrounding environment as they develop. Teratocytes were found to synthesize and release a number of proteins into culture media in which they were incubated. The proteins released differed among the different teratocyte ages. Larvae were also found to release proteins into the culture media in which they were incubated. Ligation of the head or anal vesicle altered the protein pattern found in the media. The results demonstrate that both larvae and the associated teratocytes release proteins that may have important functions in the parasitoidhost interaction. © 1994 Wiley‐Liss, Inc.
Occurrence of three different binding sites for Bacillus thuringiensis δ‐endotoxins in the midgut brush border membrane of the potato tuber moth, phthorimaea operculella (zeller)
Authors: Escriche Baltasar , Martínez‐Ramírez Amparo C. , Real M. Dolores , Silva Francisco J. , Ferré Juan
Published: February 2005

The potato tuber moth is susceptible to at least three insecticidal crystal proteins (ICPs) from Bacillus thuringiensis: CrylA(b), CrylB, and CrylC. To design useful combinations of toxin genes either in transgenic plants or in new genetically modified B. thuringiensis strains, it is necessary to determine the binding characteristics of the different ICPs so as not to combine a pair sharing the same binding site. This has been accomplished using two different techniques: 125I‐labeling of the ICPs with further measurement of the radioactivity bound to brush border membrane vesicles, and microscopic visualization of the bound ICPs by enzyme‐linked reagents such as antibodies or streptavidin using biotinylated ICPs. Our results show that CrylA(b), CrylB, and CrylC bind to different sites in the brush border membrane of midgut epithelial cells. Also, the affinity of the binding sites for the ICPs and their concentration in brush border membrane vesicles has been determined in a laboratory strain and a storage collected population. No significant differences were found between these two strains. © 1994 Wiley‐Liss, Inc.
Biosynthesis of (10R)‐Juvenile hormone III from farnesoic acid by Aedes aegypti ovary
Authors: Borovsky Dov , Carlson David A. , Ujváry István , Prestwich Glenn D.
Published: February 2005

Synthesis of (10R)‐juvenile hormone III (JH III) outside the corpora allata (CA) was investigated in female Aedes aegypti. Intact females or ligated abdomens of blood‐fed and sugar‐fed females synthesized in vivo [12‐3H]JH III‐like molecules from [12‐3H]‐methyl farnesoate, indicating that an organ(s) in the female abdomen, other than the CA, converted methyl farnesoate into JH III. To find out the organ(s) that synthesized JH III‐like molecules, ovaries, fat bodies, and midguts were incubated in vitro with [12‐3H]methyl farnesoate and the synthesis of JH III‐like molecules was compared with JH III synthesized by CA. To identify tissue(s) having both farnesoic acid methyl transferase and farnesoate epoxidase, enzymes that convert farnesoic acid into JH III, ovaries, and fat bodies were removed from sugar and blood‐fed females and incubated with [12‐3H]farnesoic acid. Chemical derivatization by methoxyhydrin formation followed by esterification with (+)‐α‐methoxy‐ α‐trifluoromethyl phenylacetic (MTPA) acid chloride and reversed phase liquid chromatography identified (10R)‐JH III methoxyhydrin (+)‐MTPA ester as the sole JH III‐like molecule produced in tissue culture incubation of ovaries. Since only (10R)‐JH III is produced and not racemic JH III, the oxidation of farnesoic acid must be enzymatically mediated. Ovaries and corpora allata of female A. aegypti also synthesized [3H,14C]JH III from L‐[methyl‐3H]methionine and [14C]acetate which was characterized by HPLC and gas chromatography. These results suggest that mosquito ovary can synthesize (10R)‐JH III from farnesoic acid, and that this tissue synthesizes JH III‐like molecules from L‐methionine and acetate. © 1994 Wiley‐Liss, Inc.
Effect of the pheromone biosynthesis activating neuropeptide on sex pheromone biosynthesis in Spodoptera littoralis isolated glands
Authors: Fabriás Gemma , Marco M. Pilar , Camps Francisco
Published: February 2005

The control of Spodoptera littoralis sex pheromone biosynthesis has been investigated with synthetic pheromone biosynthesis activating neuropeptide (PBAN) and different labeled tracers using an in vitro isolated gland system. Responsiveness of the glands to PBAN stimulation was impaired by careless tissue manipulation. The fact that PBAN is active in the isolated gland system suggests that this might be a target organ for this peptide in S. littoralis. As reported previously with Br‐SOG extracts and intact females, label incorporation into the pheromone increased in glands treated with PBAN from all the precursors tested. However, the formation of labeled intermediates from d5E11–14:Acid also occurred in glands incubated in the absence of the peptide, but the amounts of d5Z9, E11–14:Acid were lower in PBAN treated glands than in controls. These results indicate that PBAN controls pheromone biosynthesis in S. littoralis by regulating the reduction of acyl moieties. © 1994 Wiley‐Liss, Inc.