bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biosynthesis, purification, and characterization of Aedes aegypti vitellin and vitellogenin
Authors: Borovsky Dov , Whitney Philip L. 
Published: February 2005

AbstractVitellin, the major egg yolk protein, and vitellogenin, the hemolymph precursor of egg yolk protein, have been purified to apparent homogeneity from the mosquito Aedes aegypti. The purification procedure included chromatography on ion exchange, hydrophobic, and gel filtration columns. Vitellin and vitellogenin have a similar molecular weight (Mr 300,000) on gel filtration columns. However, the molecular weights of vitellin and vitellogenin, as determined from SDS electrophoresis, were 393,000 and 337,000, respectively.Vitellin in sodium dodecyl sulfate released six subunits of molecular weight 116,000, 83,000, 75,000, 54,000, 36,000, and 29,000, whereas vitellogenin released only three subunits (155,000, 120,000, and 62,000). The average molecular weights of vitellin and vitellogenin after gel filtration and SDS electrophoresis were 346,000 and 318,000, respectively.Vitellin has a high content of aspartic acid and glutamic acid, and a low content of histidine, methionine, cysteine, and tryptophan. Vitellin also contains 0.9% mol of glucosamine and no galactosamine. The isoelectric points of vitellin and vitellogenin are at pH 6.4 and 6.3, respectively.Aedes aegypti fat bodies incubated for short intervals in tissue culture medium in the presence of [3H]valine showed incorporation by radio‐immunoprecipitation and SDS electrophoresis into three primary vitellogenin polypeptides of molecular weights (± SEM) 156,000 ± 4,000, 114,000 ± 5,000, and 62,000 ± 400 inside the fat body and 162,000 ± 3,000, 118,200 ± 2,000, and 63,000 ± 300 in the medium. These results suggest that the molecular weight of vitellogenin synthesized inside the fat body (Mr 332,000) remains unchanged when secreted into the hemolymph (Mr 343,000). The three vitellogenin subunits are processed by the ovary into six subunits which are then deposited in the yolk granules as vitellin.
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

AbstractThe 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

AbstractMaturing 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

AbstractA 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

Abstract[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

AbstractPenetration 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

AbstractEndotoxin 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

AbstractPhosphoproteins 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

AbstractA 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

AbstractInjection 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

AbstractThe 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

AbstractGlutathione, 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

AbstractIn 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

Abstract1‐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

AbstractThis 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

AbstractThe 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

AbstractInsects 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

AbstractA 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

AbstractWe 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.