bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biosynthesis of dehydro‐N‐acetyldopamine by a soluble enzyme preparation from the larval cuticle of Sarcophaga bullata involves intermediary formation of N‐acetyldopamine quinone and N‐acetyldopamine quinone methide
Authors: Saul Steven J. , Sugumaran Manickam 
Published: February 2005

AbstractThe enzymes involved in the side chain hydroxylation and side chain desaturation of the sclerotizing precursor N‐acetyldopamine (NADA) were obtained in the soluble form from the larval cuticle of Sarcophaga bullata and the mechanism of the reaction was investigated. Phenylthiourea, a well‐known inhibitor of phenoloxidases, drastically inhibited both the reactions, indicating the requirement of a phenoloxidase component. N‐acetylcysteine, a powerful quinone trap, trapped the transiently formed NADA quinone and prevented the production of both N‐acetylnorepinephrine and dehydro NADA. Exogenously added NADA quinone was readily converted by these enzyme preparations to N‐acetylnorepinephrine and dehydro NADA. 4‐Alkyl‐o‐quinone:2‐hydroxy‐p‐quinone methide isomerase obtained from the cuticular preparations converted chemically synthesized NADA quinone to its quinone methide. The quinone methide formed reacted rapidly and nonezymatically with water to form N‐acetylnorepinephrine as the stable product. Similarly 4‐(2‐hydroxyethl)‐o‐benzoquinone was converted to 3,4‐dihydroxyphenyl glycol. When the NADA quinone‐quinone isomerase reaction was performed in buffer containing 10% methanol, β‐methoxy NADA was obtained as an additional product. Furthermore, the quinones of N‐acetylnorepinephrine and 3,4‐dihydroxyphenyl glycol were converted to N‐acetylarterenone and 2‐hydroxy‐3′,4′‐dihydroxyacetophenone, respectively, by the enzyme. Comparison of nonenzymatic versus enzymatic transformation of NADA to N‐acetylnorepinephrine revealed that the enzymatic reaction is at least 100 times faster than the nonezymatic rate. Resolution of the NADA desaturase system on Benzamidine Sepharose and Sephacryl S‐200 columns yielded the above‐mentioned quinone isomerase and NADA quinone methide:dehydro NADA isomerase. The latter, on reconstitution with mushroom tyrosinase and hemolymph quinone isomerase, catalyzed the biosynthesis of dehydro NADA from NADA with the intermediary formation of NADA quinone and NADA quinone methide.The results are interpreted in terms of the quinone methide model elabrated by our group [Sugumaran: Adv. Insect Physiol. 21 :179–231, 1988; Sugumaran et al.: Arch. Insect Biochem. Physiol. 11 :109,1989] and it i s concluded that the two enzyme p‐sclerotization model [Andersen: Insect Biochem. 19:59–67,375–382,1989] is inadequate to account for various observations made on insect cuticle.
Quinone and quinone methide as transient intermediates involved in the side chain hydroxylation of N‐acyldopamine derivatives by soluble enzymes from Manduca sexta cuticle
Authors: Saul Steven J. , Dali Hemalata , Sugumaran Manickam 
Published: February 2005

AbstractProteins solubilized from the pharate cuticle of Manduca sexta were fractionated by ammonium sulfate precipitation and activated by the endogenous enzymes. The activated fraction readily converted exogenously supplied N‐acetyldopamine (NADA) to N‐acetylnorepinephrine (NANE). Either heat treatment (70°C for 10 min) or addition of phenylthiourea (2.5 μM) caused total inhibition of the side chain hydroxylation. If chemically prepared NADA quinone was supplied instead of NADA to the enzyme solution containing phenylthiourea, it was converted to NANE. Presence of a quinone trap such as N‐acetylcysteine in the NADA‐cuticular enzyme reaction not only prevented the accumulation of NADA quinone, but also abolished NANE production. In such reaction mixtures, the formation of a new compound characterized as NADA‐quinone‐N‐acetylcysteine adduct could be readily witnessed. These studies indicate that NADA quinone is an intermediate during the side chain hydroxylation of NADA by Manduca cuticular enzyme(s). Since such a conversion calls for the isomerization of NADA quinone to NADA quinone methide and subsequent hydration of NADA quinone methide, attempts were also made to trap the latter compound by performing the enzymatic reaction in methanol. These attempts resulted in the isolation of β‐methoxy NADA (NADA quinone methide methanol adduct) as an additional product. Similarly, when the N‐β‐alanyldopamine (NBAD)‐Manduca enzyme reaction was carried out in the presence of L‐kynurenine, two diastereoisomers of NBAD quinone methide‐kynurenine adduct ( = papiliochrome IIa and IIb) could be isolated. The above results are in agreement with our hypothesis that N‐acylnorepinephrine formed in Manduca cuticle is biosynthesized by an indirect route involving intermediary formation of N‐acyldopamine quinone and N‐acyldopamine quinone methide as established in the case of Sarcophaga bullata and is not produced by the action of a β‐hydroxylase.
Alkanes of four related moth species, Helicoverpa and Heliothis
Authors: Carlson David A. , Milstrey Susan K. 
Published: February 2005

AbstractComparison of the presence and quantities of cuticular hydrocarbons has been used successfully for identifying sibling species and races of several groups of insects. This approach has been extended to four species of moths previously regarded as belonging to the same genus, Heliothis. Gas chromatography was used to quantify the numerous high‐molecular weight alkanes found on the cuticle of two pairs of closely related species: Helicoverpa zea and Helicoverpa armigera, and Heliothis virescens and Heliothis subflexa. Both sexes of H. zea and H. armigera contained different quantities of several alkanes that could be used for unambiguous identification. Similar comparisons of H. subflexa and H. virescens showed four peak ratios that were different for each species. Sexual dimorphism was minor in H. subflexa and H. virescens.
Ecdysteroid‐stimulated synthesis and secretion of an N‐acetyl‐D‐glucosamine‐rich glycopeptide in a lepidopterna cell line derived from imaginal discs
Authors: Porcheron Patrick , Morinière Madeleine , Coudouel Noëlline , Oberlander Herbert 
Published: February 2005

AbstractHormone‐regulated processing of N‐acetyl‐D‐glucosamine was studied in an insect cell line derived from imaginal wing discs of the Indian meal moth, Plodia interpunctella (Hübner). The cell line, IAL‐PID2, responded to treatment with 20‐hydroxyecdysone with increased incorporation of GlcNAc into glycoproteins. Cycloheximide and tunicamycin counteracted the action of the hormone. In particular, treatment with 20‐hydroxyecdysone resulted in the secretion of a 5,000 dalton N‐acetyl‐D‐glucosamine‐rich glycopeptide by the IAL‐PID2 cells. Accumulation of this peptide was prevented by the use of teflubenzuron, a potent chitin synthesis inhibitor. A glycopeptide of similar molecular weight was observed in imaginal discs of P. interpunctella treated with 20‐hydroxyecdysone in vitro, under conditions that induce chitin synthesis. Although the function of the 5,000 dalton glycopeptide is not known, we believe that the PID2 cell line is a promising model for molecular analysis of ecdysteroid‐regulated processing of aminosugars by epidermal cells during insect development.
Control of the pheromone biosynthetic pathway in Helicoverpa zea by the pheromone biosynthesis activating neuropeptide
Authors: Jurenka Russell A. , Jacquin Emmanuelle , Roelofs Wendell L. 
Published: February 2005

AbstractHormonal control of the production of the main sex pheromone component, Z11‐hexadecenal (Z11‐16:Ald), of female Helicoverpa zea was investigated using labeled precursors to monitor the pheromone biosynthetic pathway. The pathway originates with the biosynthesis of palmitic acid followed by δ11 desaturation to form the intermediate Z11‐16:Acid, which is then reduced to a primary alcohol and then oxidized to Z11‐16:Ald. Incubation of glands either in vivo or in an isolated gland culture with the deuterium labeled compounds, D3‐16:Acid or D9‐Z11‐16:Acid, yielded no differences in label incorporation into pheromone in the presence or absence of synthetic PBAN (Pheromone biosynthesis activity neuropeptide). However, unlabeled pheromone titers increased about tenfold above controls in the presence of PBAN in both in vivo and in vitro cultures. When isolated glands were incubated with [1‐14C]acetate, about a thirtyfold increase in the incorporation of radiolabel into Z11‐16:Ald above controls was observed in the presence of PBAN. Also, about a tenfold increase in incorporation was observed in saturated and monounstaturated fatty acids found in the gland upon stimulation with PBAN. These results indicate that the hormone PBAN controls pheromone biosynthesis in H. zea by regulating a step in or prior to fatty acid biosynthesis.
Plant biochemistry and aphid populations: Studies on the spotted alfalfa aphid, Therioaphis maculata
Authors: Dillwith Jack W. , Berberet Richard C. , Bergman Douglas K. , Neese Paul A. , Edwards Rose M. , McNew Ronald W. 
Published: February 2005

AbstractFeeding by the spotted alfalfa aphid, Therioaphis maculata (Buckton), on susceptible alfalfa, Medicago sativa L., results in dramatic changes in plant biochemistry that in turn have profound effects on aphid physiology. These aphids select older leaves on the plant as feeding sites. One component of this selection process may be the amount and composition of plant epicuticular lipids, which vary with leaf age. Feeding aphids induce a senescence‐like state in the leaf that is characterized by loss of chlorophyll, decreased levels of soluble protein and fatty acids, and increased production of ethylene. This process involves lipid peroxidation and, like senescence, is probably free‐radical‐mediated. Leaves of alfalfa having resistance to spotted alfalfa aphid contain higher activities of catalase than do susceptible leaves. This enzyme may function in concert with other antioxidant enzymes to quench aphid‐induced free radical damage and thus impart resistance. Aphid fatty acid metabolism is altered by changes in plant metabolism and thus reflects the close relationship between aphid and plant biochemistry.
Bioengineering of crop plants and resistant biotype evolution in insects: Counteracting coevolution
Authors: Brattsten Lena B. 
Published: February 2005

AbstractThe 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

AbstractThe 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

AbstractCalyx 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

AbstractWe 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

AbstractHomogenates 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

AbstractPolyclonal 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

AbstractThe 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

AbstractJuvenile 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

AbstractThe 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

AbstractA 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.