bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biosynthesis of a volatile, methly‐branched hydrocarbon sex pheromone from leucine by arctiid moths (Holomelina spp.)
Authors: Charlton Ralph E. , Roelofs Wendell L. 
Published: February 2005

AbstractThe biosythesis of 2‐methylheptadecane was investigated in three moth species, Holomelina lamae, H. immaculata, and H. aurantiaca, all of which use this hydrocarbon as the principal component of their volatile sex pheromone. Following injection into adult females, deuterium‐labeled leucine and isovaleric acid were readily incorporated into pheromone but valine and isobutyric acids were not. Radiolabeled acetate and malonic acid also gave good incorporation into pheromone as did 13‐methyltetradecanoic acid and 15‐methlhexadecanoic acid. These findings support a biosynthesis pathway whereby leucine is converted to isovaleric acid, which serves as the methly branch donor and chain initiator; malonic acid donates seven additional 2 carbon units to from 17‐methloctadecanoic acid, which is then deccarboxylated to produce the odd‐carbon chain hydrocarbon pheromone. Methyl‐branched fatty acids were detected in only small amounts or were absent in pheromone gland extracts, and among the different glandular lipid classes, labeled leucine and acetate were only incorporated into hydrocarbons. These findings suggest that onceinitiated, biosynthesis of the pheromone proceeds rapidly with little or no accu mulation of intermediates and/or that the pheromone or some long‐chain intermediate is biosynthesized elsewhere in the insect and transported to the gland.
Gut chitin synthase and sterols from larvae of Diaprepes abbreviatus (Coleoptera: Curculionidae)
Authors: Ward Gordon B. , Mayer Richard T. , Feldlaufer Mark F. , Svoboda James A. 
Published: February 2005

AbstractGut chitin synthase was characterized and the sterols and ecdysteroids in the sugarcane rootstalk borer weevil, Diaprepes abbreviatus, were identified. An in vitro cell‐free chitin synthase assay was developed using larval gut tissues from D. abbreviatus. Subcellular fractionation experiments showed that the majority of chitin synthase activity was located in 10,000g pellets. The gut chitin synthase requires Mg2+ to be fully active: 7–8‐fold increases in activity were obtained with 10 mM Mg2+ present in reaction mixture. Calcium also stimulated activity (4–5‐fold with 10 mM Ca2+), while Cu+2 completely inhibited at 1 mM. Other monovalent and divalent cations had little or no effect on activity. The pH and temperature optima were 7 and 25°C, respectively. Gut chitin synthesis was activated ca. 50% by trypsin treatments. GlcNAc stimulated chitin synthase activity, but Glc, GlcN and glycerin did not. Polyoxin D, UDP, and ADP inhibited the chitin synthase reaction with I50's of 75 μM, 2.3 mM, and 3.6 mM, respectively. Nikkomycin Z was a potent inhibitor of chitin synthase (91% inhibition at 10 μM). Tunicamycin and diflubenzuron had no effect on the enzyme. The apparent Km and Vmax for the gut chitin synthase were, respectively, 122.5 ± 7.4 μM and 426 ± 19.7 pmol/h/mg protein utilizing UDP‐GlcNAc as the substrate. Sterol analyses indicated that cholesterol was the major dietary and larval sterol. HPLC/RIA data indicated that 20‐hydroxyecdysone was the major molting hormone.
Spatial and temporal distribution of pheromone biosynthesis‐activating neuropeptide in Helicoverpa (Heliothis) armigera using RIA and in vitro bioassay
Authors: Rafaeli Ada , Hirsch Jaquelyn , Soroker Victoria , Kamensky Batya , Raina Ashok K. 
Published: February 2005

AbstractA [3H]‐PBAN (pheromone biosynthesis‐activating neuropeptide) analog was synthesized, and binding of the radioligand to a specific PBAN‐antiserum was achieved. The inhibition of binding of the radioligand by unlabeled PBAN, several PBAN analogs, and other competitors was studied and a specific radioimmunoassay was developed. Using this radioimmunoassay we found PBAN‐like immunoreactivity in methanol extracts of hemolymph and neural tissues from females. Higher levels of PBAN‐like immunoreactivity in extracts of brain‐suboesophageal ganglion complexes, corpora cardiaca, thoracic ganglia, and abdominal ganglia were observed during the 4‐5th h scotophase when compared to the PBAN‐like immunoreactivity levels during the 6–11th h photophase. On the other hand, the concentrations of PBAN‐like immunoreactivity in the terminal abdominal ganglion were higher during the photophase relative to minimal levels observed during the scotophase, indicating an accumulation before the onset of pheromone production. These differences in concentrations of PBAN were also reflected in the stimulation of in vitro pheromone glands, whereby significant stimulations were obtained by scotophase and photophase brain extracts, scotophase thoracic ganglia extracts, and photophase terminal abdominal ganglia extracts. No detectable levels of PBAN were found in hemolymph extracts during the sampling periods.
Functional assay for GABA receptor subtypes of a cockroach giant interneuron
Authors: Hue Bernard 
Published: February 2005

Abstractγ ‐ Aminobutyric acid (GABA) receptors were examined in the cockroach central nervous system (CNS) using the single fiber‐oil gap method applied to an identified giant interneuron. Short‐lasting pressure application of 10 mM GABA developed a multiphasic response composed of a fast hyperpolarization followed by a transient depolarizing component and a stable hyperpolarization. This triphasic characteristic shape of the response was modified according to the dose of GABA injected or bath‐applied and to the precise localization of the injection within the dendritic area. The transient depolarizing phase showed a negative reversal potential of −70 mV. Both hyperpolarizing phases reversed at a more negative level ranging to −80 mV. A positive shift of these values was caused by a decrease in external chloride concentration. Bath‐application of 0.1 mM picrotoxin (Ptx) decreased the depolarizing phase which was progressively replaced by a stable hyperpolarization. The transient depolarizing component desensitized quickly and was the most sensitive phase to Ptx action. The Ptx‐resistant response reversed at a mean value of −100 mV close to the equilibrium potential for potassium ions (EK+), suggesting that it was generated by a K+‐channel coupled receptor. Although baclofen was unable to mimic the Ptx‐resistant GABA response, the compound CGA 147823, known to bind with a high specificity to vertebrate GABAB receptors, has been successfully used to reproduce the Ptx‐resistant GABA response. It is suggested that, in addition to GABA receptors linked to chloride channels, the insect CNS possesses GABA receptors sharing ionic characteristics of GABAB receptors especially those located in the vertebrate CNS, although they are insensitive to baclofen.
Parasite‐induced enhancement of hemolymph tyrosinase activity in a selected immune reactive strain of Drosophila melanogaster
Authors: Nappi Anthony J. , Carton Yves , Frey Francoise 
Published: February 2005

AbstractLarval hemolymph tyrosinase activity in Drosophila melanogaster was detected with high performance liquid chromatography with electrochemical detection. The enzyme hydroxylated L‐tyrosine, and oxidized the diphenol substrates L‐dopa and dopamine. In larvae of a selected immune‐reactive strain the rates of tyrosine hydroxylation, dopa oxidation, and dopamine oxidation were markedly increased during the early stages of melanotic encapsulation of the eggs of the parasitic wasp Leptopilina boulardi. Tyrosinase activity was not modified in parasitized larvae of a selected susceptible strain of D. melanogaster, in which hosts the parasitoids developed unmolested. During the same period of parasitization, the amount of free tyrosine in immune reactive larvae was approximately three times higher than in susceptible hosts. These data indicate that the tyrosinase system of the immune reactive strain is activated during parasitization, and this results in the synthesis of some precursors which ultimately produce a melanotic and sclerotic capsule around the eggs of the parasite. Based on known genetic information of the enzyme system in Drosophila, it appears that at least two genes may be involved in the activation process, one associated with the proenzyme for monophenol oxidase activity, and the second with the proenzyme for diphenol oxidase activity.
Stimulation of embryonic development in microplitis croceipes (Braconidae) in cell culture media preconditioned with a fat body cell line derived from a nonpermissive host, gypsy moth, Lymantria dispar
Authors: Ferkovich Stephen M. , Dillard Charles , Oberlander Herbert 
Published: February 2005

AbstractA cell culture medium, IPL‐52B, was preconditioned with host fat body and two insect cell lines to determine if they would support embryonic development of Microplitis croceipes in vitro. The medium was preconditioned with the cell line IPL‐LdFB, derived from fat body of the gypsy moth, Lymantria dispar, cell line IAL‐TND1, derived from imaginal discs of the cabbage looper, Trichoplusia ni, and whole fat body tissue from host Helicoverpa zea. A second cell culture medium, Excell 400, was preconditioned with only the cell line, IPL‐LdFB. Pregerm band eggs were dissected from third instar host larvae and incubated in the conditioned medium for 20 h. Newly laid parasitoid eggs did not develop in unconditioned IPL‐52B, but did develop to germ band stage in unconditioned Excell 400. The IPL‐52B medium conditioned with both cell lines induced germ band formation, but only the L. dispar cell line (IPL‐LdFB) promoted significant development to eclosion comparable to host fat body tissue. Excell 400 medium preconditioned with the cell line, IPL‐LdFB also supported development to eclosion.
Temporal molt inhibition by anti‐ecdysone serum injected into lepidopteran larvae
Authors: Birkenbeil Heiner , Eckert Manfred 
Published: February 2005

AbstractInjections of an anti‐ecdysone serum into Galleria mellonella L. after the beginning of the wandering stage of the last instar resulted in delayed pupation. Injections before this time did not produce this effect and simultaneous injection of antiserum together with 20‐hydroxyecdysone leads to immediate initiation of molt. Immunocytochemical studies demonstrated the anti‐ecdysone serum specifically bound to the prothoracic glands labeling the peripheral extracellular lacunar system and sites of ecdysteroid release.
Neuromodulator octopamine attenuates extrajunctional glutamate sensitivity in insect muscle
Authors: Yamamoto Daisuke , Ishikawa Sachiyo 
Published: February 2005

AbstractOctopamine was found to decrease extrajunctional, but not junctional glutamate responses, in mealworm neuromuscular preparations. This action of octopamine was mimicked by forskolin, 8‐(4‐chlorophenylthio)‐adenosine 3′:5′‐cyclic monophosphate (CPT‐cyclic AMP), and 8‐bromoguanosine 3′:5′‐cyclic monophosphate (8‐bromo‐cyclic GMP), but not by 1,2‐oleoylacetylglycerol (OAG), a protein kinase C activator. We suggest that the octopamine‐induced reduction in the glutamate sensitivity of extrajunctional membranes may enable the muscle to more closely follow its neuronal input by preventing a depolarization (and hence a conductance increase) due to the discharge of unsequestered transmitter molecules at nonsynaptic sites.
Bacteria‐induced protein P4 (hemolin) from Manduca sexta: A member of the immunoglobulin superfamily which can inhibit hemocyte aggregation
Authors: Ladendorff Noma E. , Kanost Michael R. 
Published: February 2005

AbstractThe synthesis of a number of hemolymph proteins is induced in insects in response to bacterial infections. The major induced hemolymph protein in larvae of Manduca sexta is a glycoprotien of Mr = 48,000 known as P4. We have isolated a clone for P4 from a fat body cDNA library constructed from RNA isolated from larvae injected with bacteria. The cDNA has an open reading frame encoding a 411 residue polypeptide with a hydrophobic NH2‐terminal sequence, which appears to be a signal peptide. Analysis of the deduced amino acid sequence shows that P4 is a member of the immunoglobulin (Ig) gene superfamily, and is composed largely of four C2 type Ig domains. The M. sexta P4 amino acid sequence is 60% identical with hemolin (P4) from Hyalophora cecropia. The name “hemolin” has also been adopted for the M. sexta P4 protein. Hemolin mRNA levels in fat body begin to increase within 1 h after injection of bacteria into fifth instar larvae and within 4 h after injection of adults. Hemolin associates with the surface of hemocytes and inhibits hemocyte aggregation responses, suggesting a role for the protein in modulating hemocyte adhesion during recognition and response to bacterial infections in insects.
Comparative metabolism of isoleucine by corpora allata of nonlepidopteran insects versus lepidopteran insects, in relation to juvenile hormone biosynthesis
Authors: Brindle Philip A. , Baker Fred C. , Tsai Leslie W. , Schooley David A. 
Published: February 2005

AbstractWe studied the metabolism of [U‐14C]isoleucine by intact and homogenized corpora allata (CA) from various insect species to determine how this substrate is converted to precursors of juvenile hormone (JH). CA homogenates of the lepidopterans Manduca sexta, Hyalophora cecropia, and Samia cynthia metabolize [U‐14C]isoleucine to several products including 2‐keto‐3‐methyl‐valerate, 2‐methylbutyrate, CO2, propionate, and acetate. Intact CA of male H. cecropia produce particularly high levels of 2‐keto‐3‐methylvalerate, indicating a highly active branched‐chain‐amino acid transaminase. In contrast, CA homogenates from the nonlepidopterans Periplaneta americana, Schistocerca nitens, Tenebrio molitor, and Diploptera punctata barely metabolize [U‐14C]isoleucine. However, P. americana CA homogenate metabolizes [U‐14C]2‐keto‐3‐methylvalerate, the transamination product of [U‐14C]isoleucine, more rapidly than does a homogenate of M. sexta CA. Furthermore, intact CA from P. americana incubated with [U‐14C]2‐keto‐3‐methylvalerate incorporate low levels of 14C into JH III, but do not metabolize this substrate to JH II or JH I. Intact CA from female Diploptera punctata produce very high levels of JH III, but are also unable to incorporate radiolabel from [U‐14C]isoleucine into JH III, which substantiates our findings with other nonlepidopteran CA. The results suggest that CA of nonlepidopteran insects lack an active branched‐chain amino acid transaminase and, consequently, are unable to utilize these substrates for JH biosynthesis.
Reduced neuronal sensitivity to dieldrin and picrotoxinin in a cyclodiene‐resistant strain of Drosophila melanogaster (Meigen)
Authors: Bloomquist Jeffrey R. , Roush Richard T. , Ffrench‐Constant Richard H. 
Published: February 2005

AbstractToxicological and neurophysiological studies were performed to characterize the resistance mechanism in a cyclodiene‐resistant strain of Drosophila melanogaster (Maryland strain). Dieldrin had an LC50 of 0.058 ppm against the larvae of susceptible D. melanogaster (Oregon‐R wild type) when formulated in the rearing media. The LC50 of the resistant Maryland strain was 10.8 ppm, giving a resistance ratio (LC50‐Maryland/LC50‐susceptible) of 186‐fold. Suction electrode recordings were made from peripheral nerves of the larval central nervous system of test whether reduced nerve sensitivity played any role in the observed resistance. In susceptible preparations (n = 5), inhibition of nerve firing by 1 mM γ‐aminobutyric acid (GABA) was effectively antagonized within 3–10 min by 10 μM dieldrin. In contrast, 30 min incubations with 10 μM dieldrin had no effect on preparations from cyclodiene‐resistant individuals (n = 5). Similarly, 10 μM picrotoxinin blocked GABA‐dependent inhibition in susceptible nerve preparations (n = 3). In recordings from resistant insects (n = 4), picrotoxinin displayed either weak antagonism of GABA or hyperexcitation indistinguishable from susceptible preparations. These results demonstrate that cyclodiene resistance in the Maryland strain of D. melanogaster (1) is expressed in immature stages, (2) is present at the level of the nerve, and (3) extends to picrotoxinin, albeit at a reduced level compared with dieldrin. The possible role of an altered GABA receptor in this resistance is discussed.
Ascorbate oxidation reduction in Helicoverpa zea as a scavenging system against dietary oxidants
Authors: Felton Gary W. , Duffey Sean S. 
Published: February 2005

AbstractWe provide evidence of an important role for ascorbate free radical (AFR) reductase, dehydroascorbate (DHA) reductase, glutathione, and glutathione reductase as components of an oxidant‐scavenging system in the midgut of larval Helicoverpa zea. Also, midgut ortho‐quinone reductase is a potentially important constituent of the protective system against quinones. The midgut activities of AFR reductase, DHA reductase, glutathione reductase, and ortho‐quinone reductase were, respectively, 168, 22.1, 6, and 39.5 nmol/min/mg protein. The relatively high activity of these enzymes in the midgut provides circumstantial evidence for a protective mechanism utilizing ascorbate as an antioxidant and glutathione and/or NADPH as reductants. To our knowledge, the enzymes AFR reductase and DHA reductase have not been reported in insects. The particular relevance of this system to antioxidant protection, and in particular to the detoxication of quinones formed in damaged leaf tissues, is discussed.
Sublethal effects of chlordimeform on chemical communication and other reproductive behaviors in the female cabbage looper moth (Lepidoptera: Noctuidae)
Authors: Clark Deborah Campero , Haynes Kenneth F. 
Published: February 2005

AbstractInsecticides can affect the complex coordination of activities associated with reproduction through their sublethal impact on the nervous system. Our objective was to document the effects of a sublethal dose (1% mortality) of chlordimeform on reproductive events in the female cabbage looper moth, Trichoplusia ni. A significantly higher percentage of females treated with chlordimeform initiated calling at some time during the scotophase. Chlordimeform stimulated pheromone emission early in the scotophase. However, late in the scotophase pheromone emission was significantly lower in chlordimeform‐treated females when compared with control females. Overall, a lower amount of pheromone was detected in glands of chlordimeform‐treated females. This effect was significant only during the second half of the scotophase. We suggest that chlordimeform stimulates pheromone transport to the gland surface and calling behavior resulting in depletion of pheromone reserves over the course of the scotophase. Chlordimeform also decreased the mating success of males. Oviposition and egg hatch were also affected by chlordimeform. Mated females treated with chlordimeform laid significantly fewer eggs than acetone‐treated females. In addition, hatchability of eggs laid by mated female T. ni treated with chlordimeform was significantly lower than for eggs laid by control females.
Further characterization of nuclear DNA RFLP markers that distinguish African and European honeybees
Authors: Hall H. Glenn 
Published: February 2005

AbstractTwo nuclear honeybee DNA probes, 12R1C1 and 2A2, were reported previously to detect restriction fragment patterns specific to African and neotropical African honeybee populations. Individual drones and workers from several additional Old and New World populations, African and European, were tested further with these probes. With probe 12R1C1, only two of several Hhal fragment patterns were seen among haploid drone progeny of each queen bee, indicating that the patterns represented alleles at a single locus. Four alleles detected by probe 12R1C1 were described previously, three of which had been found only in populations of African descent. In this study, one of the three was found at a low frequency among samples from western Europe, northern Mexico, and the United States. However, ten additional alleles were discovered in South African drones, six of which were seen also in neotropical African colonies. With probe 2A2, only one or the other of two Alul restriction fragments was detected in drones indicating that the fragments represented alles at a single locus. One of the two alleles, seen previously only in populations of African descent, was found at a very low frequency in bees from western Europe and northern Mexico.
Degradation of the neuropeptide proctolin by membrane bound proteases of the hindgut and ovary of Locusta migratoria and the effects of different inhibitors
Authors: Puiroux Jacques , Loughton Barry G. 
Published: February 2005

AbstractProctolin was incubated in vitro with crude membrane preparations derived from hind gut and ovary of Locusta migratoria. The metabolites of proctolin were separated and identified by reversed phase‐high performance liquid chromatography which allowed the determination of the time course of degradation. At pHs 9.2 and 7.4, aminopeptidase activity predominated but some evidence of a carboxypeptidase could be inferred. At pH 6, aminopeptidase activity was slightly reduced compared to the level of aminopeptidase activity at the two former pHs; by contrast the carboxypeptidase was more important. At this pH, the presence of a membrane bound endopeptidase was detected.Phenanthroline, actinonin, amastatine, bestatin, and (2S,3R)‐3‐amino‐2‐hydroxy‐4‐(4‐nitrophenyl)‐butanoyl‐L‐leucine (HNBL) were tested at the concentration of 0.1 mM at pHs 8.2 and 6 and their ability to prevent the degradation of proctolin was estimated. A both pHs, HNBL and amastatin were revealed to be the most efficient inhibitors (50 to 75% inhibition) and o‐phenanthroline appeared particularly efficacious at pH 6 (70% inhibition), whereas it was relatively poor inhibitor at pH 8.2. Furthermore, the use of these inhibitors confirmed the importance of carboxypeptidase activity at pH 6.These data are the first to describe proctolin degradation in ovary and hindgut muscle, important targets of proctolin action.
Selectivity in storage hexamerin clearing demonstrated with hemolymph transfusions between Hyalophora cecropia and Actias iuna
Authors: Pan Muh‐Liang , Telfer William H. 
Published: February 2005

AbstractWhen Hyalophora cecropia hemolymph was injected into wandering Actias Iuna Iarvae, a methionine‐rich hexamerin was selectively transferred to the host's fat body, and completely cleared from the hemolymph by the time of pupal eclosion. Donor arylphorin was 30–40% removed from the hemolymph, and riboflavin‐binding hexamerin was even less completely cleared. During the pupal‐adult molt, these rates were reversed: methionine‐rich hexamerin disappeared no faster than bovine serum albumin, while riboflavin‐binding hexamerin was rapidly and completely cleared from the hemolymph, even though A. Iuna hemolymph lacks a homologue of this protein; arylphorin, again, was cleared at an intermediate rate. Selective clearing of the three hexamerins occurred at similar stages in H. cecropia, their species of origin.Developmentally programmed clearing, with selectivity at least partially conserved between genera, was also demonstrated with transfused vitellogenin: in A. Iuna females that were forming yolk, H. cecropia vitellogenin was cleared more rapidly than bovine serum albumin; but in younger females, and in males at all stages of metamorphosis, this Mr 510,000 molecule was instead an indicator of nonselective, large protein clearing.Nonselective clearing was more complete during adult development than during pupation. It also showed signs of being more effective for small than for large proteins, insensitive to carbohydrate conjugates, and unsaturated at the protein levels used.