bluuebunny/crossref_metadata_2025 huggingface dataset:
Membrane binding and uptake of diflubenzuron in a cell line from Manduca sexta (L.)
Authors: Klitschka Gabriele E. , Witt Wolfgang , Mayer Richard T.
Published: February 2005

The binding and accumulation of the chitin synthesis inhibitor diflubenzuron (DFB) by a cell line derived from embryonic tissue of the tobacco hornworm, Manduca sexta (L.), was analyzed. A rapid and reversible binding to viable and nonviable cells suspended in the culture medium was observed at soluble concentrations of DFB for short exposure periods. Scatchard analysis gave no indication of a saturable uptake mechanism. The DFB‐binding capacity of intact cells was found to be similar to that of a crude membrane preparation (70,000g pellet); however, plasma membrane‐enriched fractions bound almost three times as much DFB as the homogenate. Repetitive shorttime incubations (up to 3 h) of suspended cells with DFB resulted in a stepwise intracellular accumulation of DFB. Treatment of growing cells with DFB at high concentrations (50 μM) of DFB for longer periods (up to 7 days) resulted in elevated intracellular accumulation of DFB, which exceeded the binding capacity of the cell membranes and the aqueous solubility of DFB. These results indicate that the intracellular crystals detected by transmission electron microscopy are precipitated DFB. No metabolites or other chemically modified products of intracellular DFB were detected by high pressure liquid chromatography (HPLC) after a 7‐day incubation.
Isolation and identification of 26‐hydroxyecdysone 2‐phosphate: An ecdysteroid conjugate of eggs and ovaries of the tobacco hornworm, Manduca sexta
Authors: Thompson Malcolm J. , Svoboda James A. , Rees Huw H. , Wilzer Kenneth R.
Published: February 2005

Maturing eggs (48 to 64 h old) of the tobacco hornworm, Manduca sexta, contain at least three ecdysteroid conjugates, two of which have been previously identified as 26‐hydroxyecdysone 26‐phosphate (the major conjugate) and 26‐hydroxyecdysone 22‐glucoside. In this study we have isolated and identified the third conjugate as 26‐hydroxyecdysone 2‐phosphate by XAD‐2 chromatography, C18 SEP‐PAK separation, ion suppression reversed‐phase high‐performance liquid chromatography, nuclear magnetic resonance, and fast atom bombardment mass spectrometry. This compound is the second most abundant conjugate of ovaries from 4‐day‐old adult females. The possible role for this ecdysteroid conjugate is discussed.
Isolation and characterization of a larval hemolymph protein in Locusta migratoria
Authors: de Kort C. A. D. , Koopmanschap A. B.
Published: February 2005

A high‐molecular‐weight protein, Mr 500,000, has been isolated and characterized from the hemolymph of the migratory locust, Locusta migratoria. It is composed of six seemingly identical subunits of apparent Mr 78,000. It contains low concentrations of carbohydrate and lipid, but high percentages of aspartate and glutamate as well as high proportions of hydrophobic amino acid residues. An antiserum, developed against this purified hemolymph protein, does not react in the double‐diffusion test or after immunoblotting with purified lipophorin or cyanoprotein, two other major proteins in locust hemolymph. The concentration of this larval specific protein in the hemolymph of Locusta was examined during the last larval instar and in adult males by quantitative rocket immunoelectrophoresis. Its concentration increases in the second half of the fifth instar, concommitant with an increase in total protein. The protein is detectable by immunological techniques in adults, although its concentration is very low at this stage.
Localization of [14C]DDT in the ventral nerve cord of the cockroach, Periplaneta americana (L.)
Authors: Elia A. J. , Gardner D. R.
Published: February 2005

[14C]DDT was used as a probe to determine the subcellular localization of DDT in the ventral nerve cord (VNC) of the cockroach, Periplaneta americana (L.). Male cockroaches were injected intra‐abdominally with [14C]DDT and their VNCs removed at 1 h post‐injection. The VNCs were then subjected to homogenization and differential centrifugation to isolate plasma membrane, mitochondrial, and microsomal fractions. Results indicate that the plasma membrane fraction contained the greatest amount of [14C]DDT, with the mitochondrial and microsomal fractions containing significantly less. Calculations and a comparison with I50 values for oligomycin‐sensitive (OS)Mg‐ATPase from the literature support the prediction that an insufficient amount of DDT reaches the ventral nerve cord mitochondria of a cockroach to effect an I50 level of inhibition of the (OS)Mg‐ATPase.
Mode of entry of insecticides in Triatoma infestans
Authors: Fontán A. , Zerba Eduardo N.
Published: February 2005

Penetration of insecticides through the integument of adult and nymph V of Triatoma infestans was examined. Intersegmental membranes and the union between dorsal and ventral cuticle appear to be preferential portals of entry of [14C]parathion in adult insects. In both possible entry points, cuticle has a higher proportion of endocuticle over exocuticle, in comparison to other areas of the integument. In nymph V the whole integument seems to be the entry point for [14C]parathion, which correlates with its cuticle being almost completely composed of endocuticle. The percent penetration of [14C]parathion was almost double in nymph V compared with adult insects.

The effect of carriers on [14C]malathion penetration was that they modified the penetration rate and the mode of entry. Differences in the surface distribution of carriers with and without malathion were established.
Protease mediated prophenoloxidase activation in the hemolymph of the tobacco hornworm, Manduca sexta
Authors: Saul Steven J. , Sugumaran Manickam
Published: February 2005

Endotoxin and laminarin activated prophenoloxidase in the plasma of Manduca sexta hemolymph. Diisopropylfluorophosphate inhibited this activation, suggesting the presence of a serine protease in the activation cascade. Exogenously added proteases such as pronase, chymotrypsin, subtilisin, and thermolysin also activated prophenoloxidase in Manduca plasma. However, these enzymes did not cause any detectable activation of partially purified prophenoloxidase. Thermolysin and subtilisin mediated activation of prophenoloxidase was inhibited by p‐nitrophenyl‐p′‐guanidobenzoate. Similarly, benzamidine inhibited prophenoloxidase activation catalyzed by thermolysin. Activity measurements reveal the activation of a serine protease prior to prophenoloxidase activation. These results indicate the presence of a precursor form for the serine protease which is responsible for prophenoloxidase activation in Manduca sexta hemolymph.
Subcellular location of phosphoproteins in salivary glands of the lone star tick, Amblyomma americanum (L.)
Authors: McSwain Janis L. , Schmidt Stephen P. , Claypool Deborah M. , Essenberg Richard C. , Sauer John R.
Published: February 2005

Phosphoproteins were examined by electrophoresis and autoradiography in fractions of tick salivary glands. When whole salivary glands were preincubated in 32Pi, then stimulated by 10 μM dopamine and subsequently fractionated, substantial phosphate was incorporated into 45,000‐, 47,000‐, and 62,000‐dalton proteins of the plasma membrane‐rich 11,500g pellet and 100,000g supernatant. When tissue homogenates were incubated in [γ‐32P] ATP prior to subcellular fractionation, the 62,000‐, 47,000‐, and 45,000‐dalton proteins were enhanced by cyclic AMP in all fractions and were most prominent in the membrane‐rich 11,500g fraction. Phosphoproteins of the same molecular masses were also found in the 11,500g pellet and 100,000g supernatant when labelled with [γ‐32P] ATP in the presence of cAMP.
Phenoloxidases from larval cuticle of the sheep blowfly, Lucilia cuprina: Characterization, developmental changes, and inhibition by antiphenoloxidase antibodies
Authors: Barrett F. Michael
Published: February 2005

A tyrosinase, enzyme A (EC 1.10.3.1, o‐diphenol: O2 oxidoreductase), and a laccase, enzyme B (EC 1.10.3.2, p‐diphenol: O2 oxidoreductase), have been partially purified and characterized from larval cuticle of the sheep blowfly, Lucilia cuprina. Enzyme A is active toward a range of o‐diphenols but not p‐diphenols, is strongly inhibited by thiourea and phenylthiourea, has a pH optimum between 6.5 and 7.0, and yields a single, 60,000 molecular weight subunit following SDS gel electrophoresis. Enzyme B is active toward both o‐diphenols and p‐diphenols, is only slightly inhibited by phenylthiourea, has a pH optimum near 4.5, is highly thermostable, and has an apparent molecular weight of 90,000.

Enzyme A appears to be activated from an inactive proenzyme in the cuticle and to be present throughout the wandering phase of the final larval instar, declining at pupariation. Enzyme B is present in active form, increases greatly in the cuticle just at the time of pupariation, and then decreases as sclerotization occurs. Antibodies against enzyme A have been raised in sheep and rabbits, and against enzyme B in rabbits, but diets containing antiphenoloxidase antibodies did not affect development or mortality of fly larvae.
Effect of taurine on excitation‐induced changes in brain and hemolymph octopamine levels in Periplaneta americana
Authors: Hayakawa Y. , Bodnaryk R. P. , Downer R. G. H.
Published: February 2005

Injection of adult male cockroaches with 16 nmol taurine reduces excitationinduced elevation of hemolymph octopamine levels. Taurine‐treated insects have higher concentrations of octopamine in the brain following excitation than nontreated cockroaches. Isolated brains, incubated in taurine‐containing saline, release less octopamine in response to electrical stimulation than those incubated in saline. The effect of taurine injection on excitation‐induced octopamine release is manifested with physiological concentrations of taurine and persists for at least 15 h following injection. Excitation also causes a rapid increase in hemolymph taurine levels. The results indicate that taurine inhibits the release of octopamine from the insect nervous system and may form part of a dual control mechanism for excitation, with octopamine serving as a positive effector and taurine serving as an inhibitory modulator of octopamine release.
Inhibition of juvenile hormone III biosynthesis in cockroach corpora allata by interference with the S‐adenosylmethionine‐dependent transmethylation
Authors: Feyereisen René , Farnsworth Dan E.
Published: February 2005

The synthesis of juvenile hormone‐III by corpora allata of the cockroach Diploptera punctata is dependent under in vitro conditions upon a supply of exogenous methionine. Radiolabelled S‐adenosylmethionine was identified by HPLC in extracts of corpora allata incubated with either [methyl‐3H]methionine or [35S]methionine. Juvenile hormone (JH) synthesis by intact glands in vitro was inhibited by cycloleucine and selenomethionine, but this inhibition could be relieved by increasing the concentration of methionine. S‐adenosylhomocysteine or sinefungin had little or no inhibitory effect on JH synthesis by intact glands, but 5′‐deoxy‐5′‐methylthioadenosine was inhibitory. Adenosine and homocysteine synergistically inhibited JH synthesis. These results show that JH‐III synthesis by intact glands can be inhibited by interfering with the S‐adenosylmethionine‐dependent transmethylation, and suggest that the product and inhibitor of that reaction, S‐adenosyl‐homocysteine, is rapidly hydrolyzed to adenosine and homocysteine in the corpora allata.
Glutathione depletion associated with rose bengal‐photosensitized mortality in the housefly, Musca domestica
Authors: Wages John M. , Heitz James R.
Published: February 2005

Glutathione, pyridine nucleotides, and lipid peroxides were measured in adult houseflies following various regimens of dye treatment and light exposure. Comparisons were made between dark control and light control flies to judge the effect of light exposure alone; between dark control and dark, dye‐treated flies to evaluate the effects of dye‐feeding in the dark; and between dark, dye‐treated and light, dye‐treated flies to measure the effect of photodynamic action. No significant effect was observed in levels of NAD+, NADH, or NADP+. However, a decrease (∼ 16.7%) in NADPH during photodynamic treatment was measured. Relatively small inductions of glutathione were observed in light controls and dark, dye‐treated flies. Depletion of both GSH and total glutathione (the sum of GSH and GSSG, expressed as GSH equivalents) occurred in light, dye‐treated flies as compared to dark, dye‐treated flies. Depletion of NADPH, when related to GSH depletion, suggested that GSH is being utilized to conjugate some products of photooxidation or that it is being directly oxidized to GSSG. However, the observation of a reduction in total glutathione also suggests that a fraction of GSH is being either oxidized to a product other than GSSG or irreversibly conjugated. No significant effects from photodynamic treatment on peroxidative potential or lipid hydroperoxides were observed.
Activities of enzymes that detoxify superoxide anion and related toxic oxyradicals in Trichoplusia ni
Authors: Ahmad Sami , Pritsos Chris A. , Bowen Susan M. , Kirkland Kenneth E. , Blomquist Gary J. , Pardini Ronald S.
Published: February 2005

In third‐, fourth‐, and fifth‐instar larvae of the cabbage looper moth, Trichoplusia ni, the activities of the antioxidant enzymes, superoxide dismutase (SOD*), catalase (CAT), glutathione peroxidase (GPOX), and glutathione reductase (GR) were examined using 850 g supernatants of whole‐body homogenates. The enzyme activities, expressed as units mg−1 protein min−1 at 25°C ranged as follows: SOD, 0.67‐2.13 units; CAT, 180.5‐307.5 units; GPOX, none detectable; and GR, 0.40‐1.19 units. There was a similar pattern of changes for SOD and CAT activities with larval ontogeny, but not for GR. The cabbage looper apparently uses SOD and CAT to form a “defensive team” effective against endogenously produced superoxide anion (O2⪸). Glutathione may serve as an antioxidant for the destruction of any organic/lipid peroxides formed, and GSH oxidized to glutathione disulfide would be recycled by GR. Bioassays against pro‐oxidant compounds exogenous sources of (O2⪸) show high sensitivity of mid‐fifth instars to the linear furanocoumarin, 8‐methoxypsoralen (xanthotoxin) primarily from photoactivation (320‐380 nm), and auto‐oxidation of the flavonoid, quercetin. The LC50s are 0.0004 and 0.0045% (w/w) concentration of xanthotoxin and quercetin, respectively. Both pro‐oxidants have multiple target sites for lethal action and, in this context, the role of antioxidant enzymes is discussed.
Inhibition of juvenile hormone III biosynthesis by fluoromevalonolactone and citronellyl phenyl imidazoles in isolated corpora allata from the cockroach Periplaneta americana
Authors: Price Nicholas R. , Edwards John P. , Chambers John
Published: February 2005

1‐Citronellyl‐5‐phenyl imidazole (1,5‐CPI), 1‐citronellyl‐4‐phenyl imidazole (1,4‐CPI) and 1‐citronellyl‐2‐phenyl imidazole (1,2‐CPI) were tested as inhibitors of JH‐III biosynthesis in vitro. 1,5‐CPI was found to be most active followed by 1,2‐CPI. The least active isomer was 1,4‐CPI. Inhibition of JH biosynthesis by 1,5‐CPI resulted in no significant accumulation of the epoxidation substrate methyl farnesoate, and piperonyl butoxide, a known microsomal epoxidase inhibitor, produced only a slight increase in methyl farnesoate. Topical application of fluoromevalonolactone resulted in reduced biosynthetic capability of subsequently excised corpora allata.
Cuticular proteins: The neglected component
Authors: Willis Judith H.
Published: February 2005

This paper emphasizes the importance of the protein component of cuticles. Correlation of electrophoretic charge distribution of individual cuticular proteins and physical properties of the cuticles from which they were extracted, as well as interpopulation and interspecies conservation of electrophoretic patterns, are used to argue that individual proteins play precise roles in the cuticle. Glycosylation of cuticular proteins is described, but no function for these modifications is yet known. Analogy is drawn to analyses of chorion proteins and the case is made that analysis of amino acid sequence data is likely to provide insights into how cuticular proteins and chitin interact to construct the diverse types of cuticles.
Chemistry, biochemistry, and physiology of insect cuticular lipids
Authors: Blomquist Gary J. , Nelson Dennis R. , De Renobales Mertxe
Published: February 2005

The chemistry, biochemistry, and physiology of insect cuticular lipids are reviewed. The types of components present in cuticular extracts are described with special emphasis on the occurrence and identification of the di‐ and trimethylalkanes and the newly discovered tetramethylalkanes. The methods used in the extraction of cuticular components are discussed, including recommendations to standardize procedures. The structural elucidation of methylalkanes, particularly the mass spectral interpretation of multi‐methyl‐branched alkanes, is reviewed. The biosynthesis of cuticular lipids is discussed with emphasis on the hydrocarbon components, describing elongation reactions and the origin of the methyl branches. The effects of environment and development on cuticular lipids are reviewed.
Tyrosine metabolism for insect cuticle tanning
Authors: Kramer Karl J. , Hopkins Theodore L.
Published: February 2005

Insects have become one of the most successful animal groups in diversity and numbers through the development of a multifunctional exoskeleton and skin, which must be shed periodically in order for them to grow and develop into adults. The evolutionary choice of certain structural materials for the assembly and stabilization of a cuticle with remarkable mechanical and chemical properties has allowed insects to invade terrestrial environments and to evolve flight mechanics for dispersion relatively early in geological history. Diphenolic compounds derived from tyrosine play a central role in sclerotization or tanning of the new cuticle. The phenolic amino acid is stored during larval feeding, and it is mobilized for the production of both structural proteins and diphenolic tanning precursors that are transported into the cuticle. The latter compounds permeate the cuticle and serve as precursors for quinonoid derivatives that both sclerotize and pigment the exoskeleton. This report focuses on how tyrosine and derived diphenolic structures are stored as inactive molecules in preecdysial stages, and how they are released and metabolized to tanning chemicals that stabilize the new cuticle.
Purification and characterization of a very high density chromolipoprotein from the hemolymph of Trichoplusia ni (Hübner)
Authors: Jones Grace , Ryan Robert O. , Haunerland Norbert H. , Law John H.
Published: February 2005

A biliverdin‐carrying protein was purified to homogeneity from the larval hemolymph of Trichoplusia ni. The native protein (density = 1.26 g/ml) contains both lipid and covalently bound carbohydrate, as well as 150,000 Mr apolipoproteins. The protein is immunologically related to a similar protein from an insect belonging to the same family but is not related to known proteins from insects of other families. Also, the protein is not immunologically related to any of the other abundant hemolymph proteins found in larval Trichoplusia ni.
Male production by aphids prenatally treated with precocene: Prevention by short‐term kinoprene treatment
Authors: Hales Dinah F. , Mittler Thomas E.
Published: February 2005

We previously reported that precocene caused the aphid Myzus persicae to produce male offspring, and further, that daughters (G1) of precocene‐treated females also produced males in several temporal patterns. These patterns characteristically exhibited male production early in the reproductive sequence and/or approximately 10 days later. We suggested that ovulation of male eggs might occur at subthreshold juvenile hormone concentrations immediately after precocene treatment (i.e., during the late embryonic stages of the G1 aphids) and again in the last larval instar of the G1 aphids. This paper describes experiments in which G1 aphids were exposed to the JH analog kinoprene prenatally and in the last instar. It was shown that these treatments delayed, eliminated, or interrupted the expected sequences of males, thus providing evidence for the proposed scheme of male determination. The condition of the corpus allatum in G1 adults correlated with the pattern of male production; in continuous male producers the corpus allatum had undergone delayed destruction. A schematic model of the endocrine control of male determination is presented.
Lipid composition of housefly microsomes
Authors: Spates G. E. , Elissalde M. , Williams H.
Published: February 2005

The lipid composition of microsomes isolated from whole‐body preparations of a diazinon‐resistant strain of the housefly (Musca domestica L.) was determined. When calculated on a mg% basis housefly microsomes are composed of 47% neutral lipids and 53% phospholipids. The free fatty acids compose the major group of compounds among neutral lipids (60%) and the major phospholipid is phosphatidylethanolamine (47.6%). The molar cholesterol/phospholipid ratio is 0.14, ca. twofold higher than the ratio found in mammalian liver microsomes. Fatty acid composition of housefly microsomes is notable only in that there is no uniform distribution of fatty acid moieties throughout the various classes of lipids, except for linoleic acid (18:2), which accounted for 9.2‐12.6% of the neutral lipids. Eighty percent of the fatty acid moieties of phosphatidylserine (+ phosphatidylinositol) were unsaturated. The highest percentage of saturated fatty acid moieties (64.26%) was found in lysophosphatidylethanolamine. Palmitoleic acid (16:1), the major fatty acid found in higher dipterans, ranged from 13.51% in lysophosphatidylethanolamine to 37.45% in the free fatty acids. One prostaglandin (PGF1d) and leukotriene B4 were detected in the microsomal lipids at concentrations of 59.7 and 716 pg/200 mg of protein, respectively.
Isolation and characterization of a high molecular weight JH‐III transport protein in the hemolymph of locusta migratoria
Authors: Koopmanschap A. B. , De Kort C. A. D.
Published: February 2005

The juvenile hormone binding protein in Locusta migratoria is a very high density lipoprotein of Mr ∼ 566,000. It contains 15% lipid and is composed of six seemingly identical subunits of Mr ∼ 77,000. It is a minor protein, constituting 1–2% of the total hemolymph proteins. Its concentration fluctuates with total protein content and follows a cyclic pattern related to the molting cycles.

The binding protein has a high affinity for (10R)‐juvenile hormone III. The dissociation constant for the hormone is 3.7 ∼ 0.6 nM, and one binding molecule contains six hormone‐specific binding sites. The concentration of binding sites in the hemolymph is therefore very high, reaching a value of 26 μM in the last larval instar and 11 μM in the adult male.
Juvenile hormone‐binding protein and juvenile hormone esterase activity in hemolymph from last‐instar nymphs of Leucophaea maderae
Authors: Engelmann Franz , Mala Jaroslava , Borst David
Published: February 2005

The concentration of the juvenile hormone‐binding protein (JHB) in hemolymph was determined throughout the last nymphal instar. It was found to be 3.9 μM at the molt to the instar, rising to 13 μM by mid‐instar, and dropping to 6.7μM the day before emergence. Endocrine control of its production during the last nymphal instar could not be established. The apparent juvenile hormone esterase (JHF) activity was low at the molt to the last instar, but rose about fivefold by mid‐instar, and then modestly declined. On the day of emergence, JHF activity rose to the highest level observed. A four‐ to fivefold increase in absolute JHF activity was determined during the first half of the last nymphal instar. This increase is not regulated by JH. Removal of the JHB from hemolymph samples by precipitation with a polyclonal specific antibody increased the JHF activity up to 1,000‐fold. Thus, changes in the concentrations of JHB can affect the apparent activity of JHE, which is unrelated to the production or degradation of the JHF.
Identification and partial characterization of digestive carbohydrases in larvae of the Hessian fly, mayetiola destructor (Say) (Diptera: Cecidomyiidae)
Authors: Grover P. B. , Ross D. R. , Shukle R. H.
Published: February 2005

Several carbohydrases and glycosidases from the alimentary cancal and/or salivary glands of feeding larvae of mayetiola destructor have been identified. Pectinase activity was identified in the midgut and may be present in the salivary glands. No endocellulase activity was found in larvae; however, hemicellulase activity was detected in extract of larvae. Amylase activity was present in midguts from feeding larvae and at a low level in extract of salivary glands. Amylases detected in the midgut showed mobilities during polyacrylamide gel electrophoresis similar to the two major amylases in tissues of the insect's host plant. The possibility exists that Hessian fly larvae utilize amylases obtained from their host plant in the digestion of starch. The major glycosidases detected in the midgut lumen of larve were: α‐D‐glucosidase and α‐D‐and β‐D‐galactosidase. The role of these enzymes in the feeding process of Hessian fly larvae is discussed as well as their potential role in feeding damage to wheat.
Antioxidant enzymes of the black swallowtail butterfly, Papilio polyxenes, and their response to the prooxidant allelochemical, quercetin
Authors: Pritsos Chris A. , Ahmad Sami , Bowen Susan M. , Elliott Andrew J. , Blomquist Gary J. , Pardini Ronald S.
Published: February 2005

The black swallowtail butterfly larvae, Papilio polyxenes, are specialist feeders that have adapted to feeding on plants containing high levels of prooxidant allelochemicals. Third, fourth, and fifth instar larvae were tested for their antioxidant enzyme activities, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GPOX), using 850‐g supernatants from whole‐body homogenates. The overall antioxidant enzyme profile for P. polyxenes was high compared to other insects, with activities ranging as follows: SOD, 1.1–7.5; CAT, 124–343; GR, 1.0–7.5; and GPOX, 0 units.

To determine whether these antioxidant enzymes were inducible, P. poly xenes larvae were given a prooxidant challenge by dipping parsley leaves (their diet in the initial studies) in solutions of quercetin, such that the leaves became coated with this prooxidant flavonoid. Mid‐fifth instar larvae fed on quercetin‐coated leaves were assayed for antioxidant enzyme activities as was previously done with the larvae fed the standard diet. Food consumption and quercetin intake were monitored. SOD activity was increased almost twofold at the highest quercetin concentration tested. CAT and GR activity, on the other hand, were inhibited by increased quercetin consumption, with GR activity completely inhibited at the highest quercetin concentration after 12 h of feeding. GPOX activity, not present in control insects, was also not inducible by a quercetin challenge. These studies point out the key role that the antioxidant enzymes play in insect defenses against plant prooxidants.
Dose‐dependent influence of Campoletis sonorensis polydnavirus on the development and ecdysteroid titers of last‐instar Heliothis virescens larvae
Authors: Dover B. A. , Davies D. H. , Vinson S. B.
Published: February 2005

Campoletis sonorensis calyx fluid arrests the development of last‐instar Heliothis virescens larvae and is associated with the gross degeneration of the host's prothoracic glands. Through manipulations of ovary supernatant, Campoletis sonorensis polydnavirus (CsV) was found to be the only component of calyx fluid responsible for causing host developmental arrest. Venom from C. sonorensis had no effect on host development. Suspensions of CsV were quantified, and various doses were injected into last‐instar hosts. The percentage of larvae developmentally arrested was dose dependent. In addition, larvae not arrested by injection with CsV suspensions were developmentally delayed in a dose‐dependent manner. Hosts were delayed in the stage in which they were injected and, after recovery, developed at normal rates. Measurements by radioimmunoassay indicated that developmental delay was due to a suppression of ecdysteroid titers. After a dose‐dependent period of suppression, hemolymph ecdysteroid titers recovered and reached titers comparable to those observed in saline‐injected controls. Examination of prothoracic glands from developmentally delayed larvae revealed that partial degeneration occurred. Comparisons of the number and mean size of surviving gland cells and the length of developmental delay suggested that surviving gland cells may compensate for degenerated cells by increasing their ecdysone production.
Neuroparsin: A new energetic neurohormone in the African locust
Authors: Moreau R. , Gourdoux L. , Girardie J.
Published: February 2005

The effects of neuroparsins on hemolymph trehalose and lipid levels and on total glycogen content were analyzed in Locusta migratoria. Saline and methanol extracts of the two lobes of the corpora cardiaca were assayed. Neuroparsins (A and B) were demonstrated to be hypertrehalosemic and hyperlipemic proteins of the neural lobe. Both of these metabolic activities of neuroparsins were somewhat less potent than those of adipokinetic hormone (AKH). Neuroparsin activity could be distinguished from AKH by blockage with an antiserum specific to neuroparsin. The hypertrehalosemic response induced by neuroparsins, in contrast to that of AKH, appeared to occur without a decrease of total glycogen content. The differential modes of action of AKH and neuroparsins could contribute to the fine modulation of carbohydrate metabolism in Locusta migratoria.
Degradation of aberrant proteins by larval tobacco hornworm, Manduca sexta L. (Sphingidae)
Authors: Rosenthal Gerald A. , Dahlman Douglas L.
Published: February 2005

The tobacco hornworm Manduca sexta (Sphingidae) readily incorporates L‐canavanine, the L‐2‐amino‐4‐(guanidinooxy)butyric acid structural analog of L‐arginine, into newly synthesized proteins. As a result, the developing fifth‐instar larva produces structurally aberrant canavanyl proteins that can exhibit severely impaired function. This situation is exacerbated by canavanine's ability to stimulate de novo protein synthesis. M. sexta larvae can respond to anomalous protein production by degrading canavanyl proteins nearly five times faster than normal proteins. The proteases of this insect can distinguish between normal and anomalous proteins and thereby avoid destruction of essential macromolecules. Aberrant protein degradative activity is not dependent upon de novo protein synthesis induced by canavanyl proteins. The fat body appears to be the source of proteases that degrade aberrant proteins; degradation is curtailed in the presence of sulfhydryl protease inhibitors as well as inhibitors of trypsin‐like activity.
Fatty acids in insects: Composition, metabolism, and biological significance
Authors: Stanley‐Samuelson David W. , Jurenka Russell A. , Cripps Colleen , Blomquist Gary J. , de Renobales Mertxe
Published: February 2005

The composition, metabolism, and significance of fatty acids in insect biology are addressed. Fatty acids enter a number of metabolic pathways not directly related to energy storage and production; the unifying theme is that the fatty acids are not only structurally altered in these pathways, but that the alterations carry them from one area of biological significance into another. This theme is developed by offering a perspective on fatty acids in insects and then reviewing three major areas: 1) fatty acid composition, 2) biosynthesis of fatty acids (including polyunsaturated fatty acids and characteristics of certain biosynthetic enzymes), and 3) the biological significance of fatty acids. This last section includes discussions of the biochemistry of waxes, pheromones, and prostaglandins and the roles of fatty acids as components of defensive secretions. Little is known at the biochemical level about the regulation of fatty acid metabolism, and it is suggested that work in this area represents another frontier in insect biochemistry.
Sucrose‐dependent increase in oligosaccharide production and associated glycosidase activities in the potato aphid Macrosiphum euphorbiae (Thomas)
Authors: Walters Frederick S. , Mullin Christopher A.
Published: February 2005

Osmotic stress due to high sucrose concentration was imposed on the potato aphid, Macrosiphum euphorbiae (Thomas), in an artificial diet situation. Thin layer chromatography resolved melezitose and six additional honeydew oligosaccharides. Significantly higher levels of these oligosaccharides were recovered from the honeydew of this species in response to feeding on increased dietary sucrose concentrations, pointing to an osmoregulatory response. In addition, carbohydrase activities from the potato aphid were described. A degree of specificity toward hydrolysis of the sucrose substrate over other α‐glucosyl sugars was demonstrated. Also, sucrose was optimal for the formation of the oligosaccharides. A strong α‐galactosidase activity was found and transgalactosylation ability was indicated. These major trends in carbohydrase activity were also found in the foxglove aphid, Acyrthosiphon solani (Kaltenbach), and the oleander aphid, Aphis nerii Fonscolombe.
Characterization of juvenile hormone hydrolysis in early larval development of Trichoplusia ni
Authors: Hanzlik Terry N. , Hammock Bruce D.
Published: February 2005

Extensive juvenile hormone (JH) hydrolysis was detected and characterized in whole‐body homogenates of larvae and tissues of Trichoplusia ni during periods of early larval development. The capacity to hydrolyze JH that exists in homogenates of penultimate‐instar larvae is far in excess of the measured hormone levels. The major initial metabolites of JH found in diluted homogenates of early‐instar larvae and larval tissues were JH acid and JH diol as shown by thin‐layer chromatography and microchemical derivatization. Experiments using subcellular fractionation or immunoprecipitation and inhibition studies showed the two hydrolytic activities to be roughly equivalent but located in different subcellular compartments. JH epoxide hydrolase activity was present in the large particle and microsomal fractions, whereas most JH esterase activity was present in the cytosol. Subsequent studies concentrated on JH esterolysis. A titer of JH esterase activity throughout larval development showed this enzyme to be present continuously inside tissues, with periodic manifestations in the hemolymph during each larval molt. Partial purification by affinity chromatography and analysis with sodium dodecyl sulfate‐polyacrylamide gel electrophoresis, Western blotting, and isoelectric focusing showed JH esterase from earlyinstar larvae to be indistinguishable from the enzyme from the last instar. Application of JH II or a juvenoid, Ro 10‐3108, during any time of early larval development caused no apparent abnormalities, suggesting that the action of JH esterase is not involved with elimination of JH during this period. However, application of a JH esterase inhibitor during a critical period of the third to fourth larval molt caused failure of ecdysis, suggesting that JH acid or at least some esterase or protease may be a factor required for the molt.
Inositol phospholipid hydrolysis may mediate the action of proctolin on insect visceral muscle
Authors: Lange Angela B.
Published: February 2005

The formation of inositol phosphates in response to the neuropeptide proctolin was studied in locust oviducts. Glycerophosphoinositol, inositol 1‐phosphate, inositol 1,4‐bisphosphate, and inositol 1,4,5‐trisphosphate were identified in the locust oviducts using anion‐exchange chromatography. Proctolin stimulated the release of inositol 1‐phosphate, inositol 1,4‐bisphosphate, and inositol 1,4,5‐trisphosphate during a 5‐min incubation. In the presence of lithium ions the effects of proctolin were enhanced, with elevations of 98%, 42%, and 45% of inositol 1‐phosphate, inositol 1,4‐bisphosphate, and inositol 1,4,5‐trisphosphate, respectively.

Physiologically the effects of proctolin upon muscular contraction of locust oviducts were mimicked by the active phorbol ester, phorbol 12‐myristate 13‐acetate, and by the diacylglycerol analogue, 1‐oleoyl‐2‐acetylglycerol. The inactive phorbol ester, 12‐myristate 13‐acetate 4‐O‐methyl ether, was without effect. The effects of the active phorbol ester and the diacylglycerol analogue were calcium‐dependent requiring micromolar concentrations of calcium.

The results indicate that the locust oviducts possess proctolin receptors that are linked to phosphatidylinositol metabolism and that inositol phospholipid hydrolysis may mediate the physiological action of proctolin.
Adsorptive endocytosis of vitellogenin, lipophorin, and microvitellogenin during yolk formation in Hyalophora
Authors: Telfer William H. , Pan Muh‐Liang
Published: February 2005

Yolk in Hyalophora cecropia is a mixture of proteins that are derived from the extracellular medium. We have measured for five of these proteins the number of moles deposited in each egg, the molarity of their precursors in the hemolymph at a midpoint in vitellogenesis (day 18 of adult development), and the degree to which they are concentrated by the oocyte, relative to inulin. The proteins were isolated by gel permeation and ion exchange chromatography and used to generate antibodies in rabbits. Preliminary studies established that yolk proteins are essentially quantitatively extractable in media suitable for measuring antigen concentrations by precipitation with antibodies and that yolk and hemolymph forms of the five proteins have, effectively, the same antibody‐binding specificities as the isolated standards. Content per egg was about 900 pmol for vitellogenin, 600 pmol for microvitellogenin, and 300 pmol for lipophorin. By contrast, two hemolymph storage hexamers, arylphorin and a flavoprotein, occurred at less than 3 pmol per egg. In principle, yolk precursors are taken in both as solutes in the fluid phase of the endocytotic vesicles and as ligands adsorbed to vesicle membranes. Measurements of inulin uptake indicated that fluid phase endocytosis could account for only 4% of vitellogenin, 1% of microvitellogenin, and 15% of lipophorin in the yolk, when hemolymph precursors are at their day 18 concentrations. By the same comparison, arylphorin and flavoprotein appear to be excluded from the yolk, relative to inulin.
Developmental changes in fatty acid biosynthesis and composition in the house cricket, Acheta domesticus
Authors: Crippsc Colleen , De Renobales Mertxe
Published: February 2005

Incorporation of [1‐14C] acetate into various phospholipid and triacylglycerol fatty acids showed cyclic fluctuations in fatty acid biosynthesis that were similar for all of the major fatty acids in both male and female house crickets, Acheta domesticus, during development. All three stadia showed low levels of biosynthesis near ecdysis followed by increased synthesis to a peak at midstadium. In the phospholipid fraction, the incorporation of newly synthesized saturated fatty acids, 16:0 and 18:0, predominated near ecdysis, while at midstadium linoleic acid was the most actively synthesized fatty acid. In the triacylglycerol fraction, 18:0 and 18:1 predominated throughout the entire stadium.

In contrast to the large fluctuations in fatty acid biosynthesis, the fatty acid compositions of the phospholipid and triacylglycerol fractions did not change within a stadium. However, significant differences were demonstrated between the stages and were associated primarily with differences between nymphal and adult stadia. Males and females differed in the proportions of 16:0 and 18:2 incorporated into phospholipids with females showing a greater proportion of 18:2 and a corresponding smaller proportion of 16:0 than males. The greater proportion of linoleic acid in females and in adults in general compared to nymphs and the predominance of the incorporation of newly synthesized linoleic acid into the phospholipid fraction of all stadia are consistent with the importance of this fatty acid in a number of biological roles.
Canalization of the redbanded leafroller moth sex pheromone blend
Authors: Sreng Isabelle , Glover Thomas , Roelofs Wendell
Published: February 2005

Previous attempts to shift the (Z)‐11‐/(E)‐11‐tetradecenyl acetate ratio of pheromone components in the redbanded leafroller moth (RBLR), Argyrotaenia velutinana, by several selection protocols showed that this ratio is strongly canalized. Analysis of the complete seven‐component blend, however, showed that a Geneva laboratory stock of RBLR had a lower percent (20%) of the E9–12:OAc minor component compared to the E11–14:OAc component than a population of RBLR from North Carolina (31%). Hybrid populations from these two cultures were used in a two‐way family truncation selection scheme in which families were selected for either the lowest (low line) or the highest (high line) ratio of E9–12:OAc/E11–14:OAc. After three generations of selection, the low line had 14% E9–12:OAc relative to E11–14:OAc and the high line had 42%. The selection pressure was removed in generations 4–9, and the low line remained unchanged at 14% E9–12:OAc; but in the high line, it drifted to 53%.

Studies were conducted to estimate heritability and realized heritability. The realized heritability calculated for each generation of selection averaged 1.14 for the low line and 1.50 for the high line. These calculations, along with estimated heritability values of 0.416 and 0.644 for reciprocal crosses, indicate some plasticity in the E9–12:OAc/E11–14:OAc ratio. This ratio was positively correlated to the total amount of 12‐carbon components to 14‐carbon components, but was negatively correlated to the Z/E ratio of Δ11‐tetradecenylacetates.

The results of two studies on the canalization of various components of the RBLR sex pheromone blend indicate that there is limited potential in this insect for manipulation of the blend ratios in the laboratory.
Mode of action of diptericin A, a bactericidal peptide induced in the hemolymph of Phormia terranovae larvae
Authors: Keppi Elisabeth , Pugsley Anthony P. , Lambert Jean , Wicker Claude , Dimarcq Jean‐Luc , Hoffmann Jules A. , Hoffmann Danièle
Published: February 2005

Diptericin A is a member of a multigenic family of antibacterial peptides that are synthesized by larvae of Phormia terranovae (Diptera) in response to a bacterial injection or to injury. The 82‐residue peptide is active only against a limited range of Gram‐negative bacteria. Data presented suggest that the primary action of diptericin A is on the cytoplasmic membrane of growing bacteria.
Pheromone receptor cells in the male moth Manduca sexta
Authors: Kaissling Karl‐Ernst , Hildebrand John G. , Tumlinson James H.
Published: February 2005

Three types of pheromone receptor cells have been identified by electrophysiological recording from single antennal sensilla trichodea of the male sphinx moth Manduca sexta. These cells responded best to the pheromone components (E,Z)‐10,12‐hexadecadienal (type A receptor cell), (E,E,Z)‐10,12,14‐hexadecatrienal (type B), and (E,E,E)‐10,12,14‐hexadecatrienal (type C). Cell type B also responded to (E,Z)‐11,13‐pentadecadienal, which has been used experimentally as a pheromone substitute. In recordings from 20 trichoid hairs, 17 were found to be innervated by one cell of type A and one of type B; 3 trichoid hairs had cell types A and C.
Sex pheromone blend of Manduca sexta: Responses of central olfactory interneurons to antennal stimulation in male moths
Authors: Christensen Thomas A. , Hildebrand John G. , Tumlinson James H. , Doolittle Robert E.
Published: February 2005

Recently, chemical analysis of solvent rinses of the external surfaces of pheromone glands from female Manduca sexta revealed a blend of 12 aldehydes, including the previously identified sex pheromone component, (E,Z)‐10,12‐hexadecadienal (bombykal). Previous electrophysiological studies showed that olfactory (deutocerebral) interneurons in the antennal lobes of males exhibited a wide range of responsiveness to pheromonal stimulation of the ipsilateral antenna. These experiments were performed with crude extracts of pheromone glands as well as two synthetic compounds: the major pheromone component, bombykal, and (E,Z)‐11,13‐pentadecadienal, a mimic of a second component of the female's pheromone blend. Using intracellular methods, we have now reexamined similar olfactory interneurons, using each of the 12 chemically identified components as well as synthetic blends of various combinations of them. Eight of the 12 components isolated from female glands elicited some form of response in olfactory interneurons in males. In accordance with biochemical and behavioral data, the most potent are bombykal and two trienals, (E,E,E)‐ and (E,E,Z)‐10,12,14‐hexadecatrienal. We also conclude that the C15 dienal is selective for one of the trienal receptors on the antenna, but is much less potent than the natural trienal stimulant.
Degradation of juvenile hormone and methylation of juvenile hormone acid by corpora cardiaca–corpora allata of the cockroach, Nauphoeta cinerea: I. Biochemical aspects
Authors: Meyer Walter R. , Lanzrein Beatrice
Published: February 2005

Corpora cardiaca‐corpora allata (CC‐CA) from vitellogenic females of Nauphoeta cinerea degraded, in vitro, racemic and (10R)‐juvenile hormone III (JH III) at a rate of 249 pmol/CC‐CA/h and 786 pmol/CC‐CA/h, respectively. The major metabolite formed was JH III acid, together with some highly polar products. CC‐CA homogenates degraded racemic JH III to a small extent, whereas (10R)‐JH III was degraded efficiently to JH III acid. No highly polar products were formed by CC‐CA homogenates. When CC‐CA were incubated with racemic JH III acid, some of this substance was degraded to highly polar products, and a minor part was methylated to JH III. CC degraded very little JH III acid and did not methylate it to JH III. CC‐CA homogenates methylated JH III acid very efficiently; we measured an apparent Kmax of 37.8 μM and a Vmax of 1,260 pmol/4 h/ CC‐CA equivalent. The addition of JH III acid to CC‐CA in vitro increased the rate of biosynthesis of JH III, as determined by measuring incorporation of methyl[14C]methionine into JH III. These data indicate that the metabolite JH III acid can enter the CA and be methylated to JH III.
A high molecular weight diapause‐associated protein from the stem‐borer Busseola fusca: Purification and properties
Authors: Osir Ellie O. , Labongo Lanek V. , Unnithan Gopalan C.
Published: February 2005

The hemolymph of diapausing larvae of the stem borer, Busseola fusca Fuller (Lepidoptera: Noctuidae), contains an electrophoretically distinct protein band on nondenaturing polyacrylamide gels. The protein, called the Busseola diapause protein (BDP), was purified by a combination of density gradient ultracentrifugation, gel permeation, and affinity chromatography. It is a high molecular weight protein (Mr ∼5 × 105; pl = 6.1) that is composed of two subunits, I (Mr ∼88,000 ± 4,000) and II (Mr ∼79,000 ± 1,000), which are not linked by disulfide bridges. The protein contains both lipids (2%) as well as covalently bound carbohydrates (1%). The inability to stain the fluorescein isothiocyanate‐conjugated concanavalin A (FITC‐Con A) suggests that the carbohydrate moiety of BDP is not of the high mannose type. Amino acid analysis showed a high tyrosine plus phenylalanine content (16 mol%). Labeling studies using [35S]‐methionine showed that de novo synthesis by the fat body tissue occurs only in diapausing larval insects. It is proposed that the BDP could serve a storage function by providing the amino acids needed for the synthesis of pupal and adult structures.