bluuebunny/crossref_metadata_2025 huggingface dataset:
Bioengineering of crop plants and resistant biotype evolution in insects: Counteracting coevolution
Authors: Brattsten Lena B.
Published: February 2005

The use, as opposed to the procurement, of transgenic crop plants is discussed in this paper. Transgenic crop plants must not be used until appropriate strategies for their use have been designed and not before crop plants with a variety of insect defenses have been developed. The use of a crop plant with a single defense will pose as strong a selection pressure as the use of a single synthetic insecticide, since insect herbivores are able to evolve effective counter‐defenses. The defenses of insects in natural plant‐insect associations and with regard to synthetic insecticides are described to demonstrate that there is nothing unique about insecticide resistance. It is the inevitable alternative to local extinction in response to a persistent and predictable selection pressure. Plants counteract insect defensive evolution by keeping the selection pressure as variable as possible. This leads to the conclusion that the best use of biotechnology in crop protection is to reintroduce chemical diversity into crop plants.
Correlation among corpus allatum volume, cell size, and juvenile hormone biosynthesis in ovariectomized adult Blattella germanica
Authors: Chiang Ann‐Shyn , Schal Coby
Published: February 2005

The corpora allata (CA) of both intact and ovariectomized Blattella germanica adult females exhibited a high degree of bilateral symmetry in the rate of juvenile hormone (JH) biosynthesis, the mean size of CA cells, and gland volume (81.3%, 98.3%, and 100% respectively with less than a twofold difference between the two glands in CA pairs). This permitted us to split each CA pair randomly, measure JH biosynthesis in one gland, and dissociate the other gland into a cell suspension in which the size of CA cells was measured. In ovariectomized females, changes in CA volume and the spontaneous and farnesoic acid (FA)‐stimulated rates of JH biosynthesis, measured from the same glands, were well correlated (r = 0.78, for both correlations). Similarly, the mean volume of CA cells in one gland increased in relation to increases in both the spontaneous and FA‐stimulated rates of JH biosynthesis by the contralateral member of the pair (r = 0.83 and r = 0.91, respectively). Concurrent changes in CA cell size and activity suggest that in the CA of B. germanica cellular growth and degradation are involved in the regulation of JH biosynthesis.
Developmental disruption of pseudoplusia includens and Heliothis virescens larvae by the calyx fluid and venom of microplitis demolitor
Authors: Strand Michael R. , Dover Barry A.
Published: February 2005

Calyx fluid and venom from the braconid parasitoid Microplitis demolitor differentially affected the development of Pseudoplusia includens and Heliothis virescens. P. includens exhibited delays in larval development, supernumerary instars, and formed larval‐pupal intermediates when injected with 0.01–0.10 wasp equivalents of calyx fluid. In contrast, H. virescens was relatively unaffected by calyx fluid regardless of dose. Venom did not affect the development of either host species, but appeared to synergize the activity of calyx fluid. This was particularly evident in H. virescens, where injection of 0.10–0.20 wasp equivalents of calyx fluid and venom induced the formation of a large number of intermediates while the same amount of calyx fluid did not. The particulate portion of M. demolitor calyx fluid was the only component that caused developmental delays and the formation of intermediates in both host species. Purified virus caused developmental alterations in P. includens, while trioxsalen treated calyx fluid did not affect development of P. includens or H. virescens. These data suggest the requirement for venom in parasitism may differ between host species, and that dosage plays an important role in interpreting the interaction between calyx and venom components.
Benzoylphenyl ureas inhibit chitin synthesis without interfering with amino sugar uptake in imaginal wing discs of Plodia interpunctella (Hübner)
Authors: Oberlander Herbert , Silhacek Donald L. , Leach Eddie , Ishaaya Isaac , Shaaya Eli
Published: February 2005

We tested the hypothesis that the inhibition of chitin synthesis by benzoylphenyl ureas could be explained by their effect on the uptake of GlcNAc into chitin. Our test system consisted of organ cultures of wing imaginal discs from Plodia interpunctella. These wing discs synthesize chitin in response to 20‐hydroxyecdysone or RH 5849, a non‐steroidal ecdysteroid mimic. Two benzoylphenyl ureas, diflubenzuron and teflubenzuron, inhibited ecdysteroid‐dependent chitin synthesis in the wing discs. However, although chitin synthesis was inhibited, there was no corresponding diminution of amino sugar uptake by the imaginal discs. In another experiment 20‐hydroxyecdysone stimulated uptake of two sugars, 2‐deoxy‐D‐glucose and 3‐O‐methyl‐D‐glucose, which are not synthesized into chitin. Transport of these non‐metabolized sugars was unaffected by the inhibitors. In an additional test of the effects on precursor transport, the action of ecdysone (alpha‐ecdysone) was examined. Ecdysone stimulated amino sugar uptake, but not chitin synthesis. Neither diflubenzuron nor teflubenzuron inhibited ecdysone‐dependent precursor transport. Finally, we examined ecdysteroid‐induced uptake of amino sugars by an imaginal disc derived cell line IAL‐PID2. In this case, also, GlcNAc transport was not inhibited significantly by either diflubenzuron or teflubenzuron. From these observations we conclude that inhibition of uptake of amino sugars does not account for the ability of teflubenzuron and diflubenzuron to inhibit chitin synthesis in P. interpunctella wing discs.
Properties of chitin synthase in homogenates from Chironomus cells
Authors: Ludwig Monika , Spindler‐Barth Margarethe , Spindler Klaus‐Dieter
Published: February 2005

Homogenates of Chironomus cells synthesize chitin as effectively as intact cells. Chitin is produced in a dose‐dependent manner, when GlcN, GlcNAc, or UDP‐GlcNAc is used as precursor. Due to the lability of UDP‐GlcNAc incorporation of this substrate is underestimated. No allosteric effect is observed when GlcN or GlcNAc is used as a substrate. Chitin synthesis is stimulated by Mg2+ and inhibited by uridine monophosphate (UMP), uridine diphosphate (UDP), and uridine triphosphate (UTP). The apparent temperature optimum is 30°C, the apparent pH optimum is 5.5–6. Addition of the chitinase inhibitor allosamidin does not enhance chitin synthesis significantly. The time course of chitin formation reveals a lag period of about 12 h, which can be overcome by trypsin treatment. Addition of protease inhibitors prevents chitin synthesis.
Detection and determination of Locusta migratoria trypsin by radioimmunoassay
Authors: Sakal Edna , Birk Yehudith , Applebaum Shalom W.
Published: February 2005

Polyclonal antibodies were produced against trypsin‐like enzyme TLE‐2, one of two trypsins isolated from the midgut cecae of the locust Locusta migratoria. Using those antibodies a heterologous RIA was developed. The specificity of the antibodies was demonstrated by immunoblot technique and cross‐reactivity experiments. Positive blot reaction with the antiserum was observed with locust trypsins and binding competition was obtained only with the second trypsin from the locust, TLE‐1. Trypsins from bovine and hog as well as trypsins from Tenebrio molitor and Tribolium castaneum and locust chymotrypsin did not inhibit TLE‐2 binding to the antiserum even at concentrations 1,000‐fold greater than that of locust TLE‐2. The concentrations of TLE‐2 in cecal fluid, cecal wall, hemolymph, and fat‐body were 2,790, 60.4, 6.4, and 0.7 ng per mg tissue, respectively. © 1992 Wiley‐Liss, Inc.
A FMRFamide‐like peptide is associated with the myotropic ovulation hormone in Rhodnius prolixus
Authors: Sevala Veeresh L. , Sevala Venkatalakshmi M. , Davey Kenneth G. , Loughton Barry G.
Published: February 2005

The protocerebral neurosecretory cells previously shown to be the source of the myotropin controlling ovulation in Rhodnius prolixus react in an immunocytochemical assay using an antiserum against FMRFamide. When the same antiserum was injected into fed mated females at the appropriate time the timing of oviposition was delayed, but the total number of eggs developed was unaffected compared to controls injected with pre‐immune rabbit serum. The titer of FMRFamide‐like peptide (assayed by RIA) in the hemolymph of mated and virgin females was found to fluctuate with the egg laying cycle, and to reflect earlier determinations of the titer of myotropic activity. Western blots of SDS‐PAGE revealed a FMRFamide‐immunoreactive peptide of approximately 8.5 kDa in both hemolymph and extracts of the ovulation hormone cells. © 1992 Wiley‐Liss, Inc.
Juvenile hormone esterase activity and ecdysteroid titer in Heliothis virescens larvae injected with Microplitis croceipes teratocytes
Authors: Zhang Deqing , Dahlman Douglas L. , Gelman Dale B.
Published: February 2005

Juvenile hormone esterase (JHE) activity in the hemolymph of 5th‐instar Heliothis virescens larvae injected with Microplitis croceipes teratocytes was inversely related to the number of teratocytes injected. JHE activity in the hemolymph of larvae injected with 750 3‐day‐old teratocytes (the approximate number from one parasitoid embryo) was depressed to less than 5% of those levels found in control larvae. During the latter portion of the digging stage and in the burrowing‐digging (BD) stage JHE activity in larvae treated with 350 teratocytes was approximately 40% of control values. However, injection of 180 teratocytes did not significantly affect JHE titers. Two‐day‐old teratocytes caused the greatest reduction in JHE titer with decreasing effects observed with injections of 3‐ to 6‐day‐old teratocytes. Nevertheless, because 2‐day‐old teratocytes were difficult to separate from host hemocytes, 3‐day‐old teratocytes were used in most of these studies. Injections of nonparasitized H. virescens hemolymph plasma, Micrococcus luteus bacterial cell walls, washed M. croceipes eggs, or teratocytes from Cotesia congregata did not depress JHE titers. Teratocyte injections also significantly reduced growth of host fat body. Ecdysteroid titers in cell formation, day 2 (CF2) larvae injected as new 5th instars with 350 3‐day‐old teratocytes failed to increase, as compared to noninjected and saline‐injected controls. An injection of 1 μg/larva of 20‐hydroxyecdysone at the BD stage permitted normal pupation in 50% of the teratocyte‐treated larvae as compared to 0% pupation for teratocyte‐treated control larvae not treated with 20‐hydroxyecdysone. Teratocytes seem to be responsible for the inhibition of JHE release and thus indirectly impact on ecdysteroid titers. © 1992 Wiley‐Liss, Inc.
Role of phospholipids in the lipophorin particles of Rhodnius prolixus
Authors: Gondim Katia Calp , Atella GeóRgia CorrěA , Masuda Hatisaburo , Kawooya John K.
Published: February 2005

The lipophorin of Rhodnius prolixus metabolically labelled with 32P exclusively in the phospholipid moiety was purified on a potassium bromide gradient and treated with phospholipase A2 in the presence of an excess of fatty acid‐free albumin. The treatment completely removed the phospholipids from the particles and generated [32P]‐lysophosphatidylcholine, [32P]‐lysophosphatidylethanoamine, and free fatty acids that remained bound to albumin. The phospholipid‐depleted lipophorin particles remained soluble, indicating that phospholipids are not essential in maintaining the stability of the particles in aqueous solution. Complete removal of phospholipids did not affect the association of apolipophorin III with lipophorin particles. Lipophorin density increased slightly from 1.120 to 1.134 g/ml after treatment. The phospholipid‐depleted particles aslo retained their ability to be recognized and loaded in vitro with phospholipids delivered by the fat body, thus supporting the concept of lipophorin's role as a reusable lipid shuttle for phospholipids. © 1992 Wiley‐Liss, Inc.
A diapause associated protein of the pink bollworm Pectinophora gossypiella saunders
Authors: Salama Mohamed S. , Miller Thomas A.
Published: February 2005

A diapause associated protein was electrophoretically isolated from the hemolymph of diapausing last instar larvae of the pink bollworm Pectinophora gossypiella. This protein (Mr ∼490,000, glycolipoprotein) was given the name Pectinophora diapause protein (PDP). It is composed of one subunit (Mr 103,000). The concentration of PDP increased dramatically in the hemolymph of diapausing larvae from 17.4% in prediapause (PD) phase to 29.2% in early diapause (ED) phase reaching a level of 38.6% in larval hemolymph of middiapause (MD) phase. The concentrations of total proteins in the hemolymph of active feeding (A), PD, ED, and MD larvae were 69.8, 106.6, 113.3, and 118 mg/ml, respectively, while those in the fat body of the same larvae were 7.1, 7.4, 8.8, and 4.5 mg/g, respectively. In Pectinophora a drop in the concentration of fat body proteins coincided with a corresponding increase in hemolymph proteins, which suggests an active release of protein from the fat body into the hemolymph during the development of diapause. A partial amino acid sequence of pectinophorin showed the first 15 amino acids starting from the amino terminus of the peptide chain: N‐ALA‐LYS‐THR‐ILEU‐VAL‐GLU‐ASN‐MET‐PRO‐PRO‐THR‐PRO‐LEU‐ASN‐ALA‐C. © 1992 Wiley‐Liss, Inc.
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

Egg 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

The 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

Regulation 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 ecdysone

Abbreviations 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

A 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

Phenol 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

In 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

The 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

Cold 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

Philanthotoxin (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

In 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

Pyrethroid 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

Developmental 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

Diploptera 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

Whole 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.
Stimulation of vitellogenin production by methoprene in prepupae and pupae of manduca sexta
Authors: Satyanarayana Kotamraju , Bradfield James Y. , Bhaskaran Govindan , Dahm Karl H.
Published: February 2005

Denaturing electrophoresis of hemolymph from prepupae of M. sexta showed trace amounts of polypeptides with mobilities corresponding to those of vitellogenin (Vg) apoproteins from adult females. Absence of the polypeptides in allatectomized insects suggested regulation by juvenile hormone (JH). Daily administration of 10 μg of the JH analog methoprene from day 4 of the fifth stage to day 0 of the pupal stage caused accumulation of these polypeptides. They were identified as apovitellogenins (apoVgs) immunochemically with Vg antiserum. Stimulation of Vg in response to methoprene varied with age. In all cases, day 0 female pupae were highly responsive. Vg synthesis was not stimulated when pupae were injected with 20‐hydroxyecdysone (20‐HE) in addition to methoprene. Methoprene‐stimulated Vg synthesis was also abolished by inhibitors of mRNA or protein synthesis (α‐amanitin, actinomycin, cycloheximide). This result indicated that methoprene‐stimulated Vg accumulation requires gene expression. A Vg cDNA (2.1 kb) obtained by immunoscreening of the λgt 11 library, when used as a radiolabelled probe, hybridized with a 5.1 kb mRNA from total RNA of female fat body. It also hybridized with fat body RNA of normal prepupae and methoprene treated day 0 pupae but not with that of early fifth instars or solvent control pupae. The results indicate that the trace amounts of Vg found in prepupal stages are due to a weak expression of the Vg gene, which is stimulated by JH and repressed by 20‐HE. © 1994 Wiley‐Liss, Inc.
Hydrocarbon biosynthesis in Triatoma infestans eggs
Authors: Juárez Patricia
Published: February 2005

Triatoma infestans eggs are shown to synthesize hydrocarbons. Radio‐gas chromatography was used to demonstrate metabolism of [1‐14C]propionate into precursor methyl‐branched fatty acids and into methyl‐branched hydrocarbons in T. infestans eggs. These reactions have not been demonstrated previously in insect eggs. An in vivo study showed that hydrocarbons are also transported to eggs by the hemolymph. Inhibition of hydrocarbon synthesis by sodium trichloroacetate (NaTCA) was correlated with reduced oviposition, reduced hatchability, and reduced insect survival. Scanning electron microscopy showed impoverishment of the eggs' epicuticular waxes following NaTCA treatment. © 1994 Wiley‐Liss, Inc.
Chitin synthesis in Spodoptera frugiperda wing imaginal discs: I. Chlorfluazuron, diflubenzuron, and teflubenzuron inhibit incorporation but not uptake of [14C]N‐acetyl‐D‐glucosamine
Authors: Mikołajczyk Piotr , Oberlander Herbert , Silhacek Donald L. , Ishaaya Isaac , Shaaya Eli
Published: February 2005

The purpose of this study was to determine the effects of potent inhibitors of chitin synthesis on an organ culture test system as a basis for determining the mode of action of such compounds. Consequently, we investigated the action of chlorfluazuron (CFA), diflubenzuron (DFB), and teflubenzuron (TFB) on uptake and incorporation into chitin of [14C]N‐acetyl‐D‐glucosamine ([14C]GlcNAc) in wing imaginal discs cultured in vitro. Spodoptera frugiperda wing imaginal discs provided a highly responsive test system for studying the inhibition of ecdysteroid‐dependent chitin synthesis in a target tissue in vitro.

All three inhibitors blocked ecdysteroid‐dependent [14C]GlcNAc incorporation into chitin by the wing imaginal discs. The effectiveness of the inhibitors was not affected by the time of their application, i.e., exposures before, during, or after 20‐hydroxyecdysone treatment were equally effective in inhibiting chitin synthesis. Thus, exposure of freshly dissected discs to CFA for periods as short as 15 min inhibited approximately 90% of the chitin synthesis measured 72 h later. In contrast to previous in vivo studies all three inhibitors were similar in their effectiveness in vitro. However, while all three compounds inhibited [14C]GlcNAc incorporation in a similar dose‐dependent manner, only DFB and TFB reduced but did not block uptake of GlcNAc. © 1994 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Factors affecting pheromone production in beetles
Authors: Vanderwel Désirée
Published: February 2005

Pheromone production and/or release by beetles is coordinated with a variety of behavioral, physiological, and environmental factors. To data, two basic mechanisms for the regulation of pheromone biosynthesis in beetles have been proposed. Pheromone biosynthesis may simply be dependent on the availability of biosynthetic precursors. Alternatively, certain stimuli or events may trigger pheromone biosynthesis via juvenile hormone (JH) action. JH may either act directly at the site of pheromone biosynthesis to enhance pheromone production or may act indirectly, through a brain hormone (which might be related to the pheromone biosynthesis activating neuropeptide) or through effects on antennal sensory response. Knowledge of the regulation of the initiation and termination of pheromone biosynthesis is reviewed. Mechanisms by which pheromone stereochemistry is controlled are also discussed. This is an important aspect of pheromone production in Coleoptera, since slight changes in the stereochemistry can completely alter the activity of the molecule. © 1994 Wiley‐Liss, Inc.
Development and partial characterization of monoclonal antibodies to venom of the parasitoid microplitis demolitor
Authors: Strand Michael R. , Johnson Jena A. , Noda Takashi , Dover Barry A.
Published: February 2005

The venom of Microplitis demolitor consists of a mixture of proteins. On native PAGE gels three major proteins designated a, b, and g were detected, while on SDS‐PAGE gels two major proteins of Mr 64.5 and 30.8 kD and several minor proteins were detected. No proteins smaller than Mr 30.8 kD were present. Murine monoclonal antibodies were generated against different venom components. Analysis by Western blot of venom proteins separated on native and SDS‐PAGE gels confirmed that antibodies from seven hybridoma lines recognized venom components. Two of the seven hybridoma lines reacted specifically with protein g on native PAGE gels and the Mr 30.8 k protein on SDS‐PAGE gels, while four other lines cross‐reacted with these and other venom proteins. The final hybridoma line reacted with protein a when venom was separated on native PAGE gels and an array of proteins when venom was separated on SDS‐PAGE gels. Using an enzyme‐immunoassay and specific monoclonal antibodies, M. demolitor females were estimated to inject 0.02—0.05 venom gland reservoir equivalents into its host, Pseudoplusia includens, at oviposition. Venom proteins persisted in host hemolymph for 6—12 h before dropping to undetectable levels. © 1994 Wiley‐Liss, Inc.
Cloning of a VLP‐protein coding gene from a Parasitoid Wasp Venturia canescens
Authors: Theopold Ulrich , Krause Elke , Schmidt Otto
Published: February 2005

Virus‐like particles (VLPs) that are bound to the egg surface of a parasitic wasp Venturia canescens are void of nucleic acid and unable to infect host tissue but instead provide a passive protection against the host's immune recognition. To investigate evolutionary and functional properties of Venturia particles, we isolated cDNAs coding for a VLP‐protein by screening an expression library of the wasp, using antibodies against purified VLPs. The corresponding coding DNA is present in the wasp genome as a single‐copy gene. © 1994 Wiley‐Liss, Inc.
Octopamine enhances phagocytosis in cockroach hemocytes: Involvement of inositol trisphosphate
Authors: Baines Danica , Downer Roger G. H.
Published: February 2005

Octopamine and 5‐hydroxytryptamine (5‐HT) were previously shown to affect phagocytosis in cockroach hemocytes through unidentified receptor‐mediated events. In the present study, we examined the ability of 5‐HT and octopamine to enhance inositol trisphosphate (IP3) production using hemocyte membranes of the American cockroach, Periplaneta americana. Octopamine enhanced IP3 production with a maximal peak at 100 nM. Similarly, 5‐HT enhanced IP3 production with a maximal effect at 10 nM. The effects of 5‐HT and octopamine are not additive, suggesting that both are working through the same receptor. Phentolamine, a general octopamine antagonist, blocked the effects of octopamine and 5‐HT, while a mammalian 5‐HT2 antagonist that blocks 5‐HT‐sensitive receptors in insect peripheral tissue, ketanserin, did not. A pharmacological profile indicates that the receptor is similar to an octopamine1‐type.

Octopamine at 1 μM increased phagocytosis in cockroach hemocytes exposed to Staphylococcus aureus in vitro, and this effect was mimicked by IP3 (10 μM). The octopamine‐treated hemocytes were shown to increase IP3 production in the latter stage of phagocytosis.

Adult cockroaches exposed to an LD50 dose of S. aureus in conjunction with either 0.1 mM octopamine or the octopamine1 agonist, clonidine, had higher survival rates compared to saline‐treated cockroaches. Correspondingly, the octopamine1 antagonist, chlorpromazine, partially blocked the octopamine‐mediated increase in cockroach survival. © 1994 Wiley‐Liss, Inc.
Inhibition by azadirachtin of phospholipid transfer from lipophorin to the oocytes in Rhodnius prolixus
Authors: Moreira Monica F. , Garcia Eloi S. , Masuda Hatisaburo
Published: February 2005

The growth of oocytes was severely reduced in female Rhodnius prolixus treated with azadirachtin A (AZA). When administered in a blood meal, AZA (1 μg/ml) inhibited phospholipid transfer to the ovaries without altering the availability of yolk protein in the hemolymph or its uptake by 1 mm oocytes. The lipid composition of lipophorin, its concentration in the hemolymph, and its density were normal in AZA‐treated females. Partial inhibition of phospholipid transfer was observed when lipophorin from AZA‐treated females was injected into normal females, or when lipophorin from normal females was injected into AZA‐treated females. The two effects were additive, so that the transfer of phospholipids from the lipophorin of AZA‐treated females to the oocytes of AZA‐treated females was nearly eliminated. In combination, these effects of AZA on phospholipid transfer to the oocytes limit the capacity of AZA‐treated females to produce eggs. © 1994 Wiley‐Liss, Inc.