bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemosetting resins containing fillers. I. Unsaturated polyester resin compositions containing modified smectites
Authors: Oleksy Mariusz , Heneczkowski Maciej , Galina Henryk 
Published: February 2005

AbstractSmectic clays with quaternary ammonium salts (QAS) were subjected to hydrophobization, whereupon we applied the products in attempts to modify various polymers. The clays were of natural origin and contained a large proportion of montmorillonite and an original method of modification was applied. A significant improvement of the stability of unsaturated polyester (UP) resins, modified with clays modified with QAS, was observed with essentially no change in the reactivity of resins. The compositions of polyester resins containing 2 wt % of modified smectites had excellent thixotropy. The presence of modified bentonites in a cured commercial UP resin (2–4 wt %) improved its tensile strength (by 21–62%), Brinell hardness (23–70%), and unnotched impact strength (23–100%), depending on the type of bentonite used. The compositions of UP resins with modified clays had certain properties typical for nanocomposites: improved stiffness, strength, transparency, and fine‐lamellar morphology of the fracture as found by electron scanning microscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 793–801, 2005
Synthesis and characterization of water‐soluble conducting polyaniline by enzyme catalysis
Authors: Shen Yuping , Sun Jianzhong , Wu Jiangang , Zhou Qiyun 
Published: February 2005

AbstractEnzymatic synthesis of a water‐soluble, conducting polyaniline (PANI) was studied, using horseradish peroxidase as the biocatalyst and H2O2 as the initiator, in the presence of a poly(vinylsulfonic acid, sodium salt) (PVS) polyanion template. The effects of the buffer, concentration of H2O2, and the molar ratio of aniline to PVS on the polymerization were particularly investigated. The products were characterized by UV–vis/near‐IR and FTIR spectroscopy, thermogravimetric analysis, and four‐point probe conductivity measurement. The results showed that PVS could be chosen as a new template in the synthesis of PANI. The proper conditions of polymerization were obtained as follows: pH of the buffer was pH 4.0–5.0, the concentration of H2O2 was around 20 mM, and the molar ratio of PVS to aniline was 1–1.5. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 814–817, 2005
Characterization of mannosyl transferases during the pupal instar of Stomoxys calcitrans (L)
Authors: Mayer RicharD. T. , Chen A. C. , Deloach J. R. 
Published: February 2005

AbstractParticulate fractions (10,000g) from pupae of Stomoxys calcitrans transfer [14C]‐mannose from GDP‐[14C]‐mannose to dolichol monophosphate and proteins. Production of the mannosyl lipid was inhibited by Mn2+, UDP, GMP, GDP, and EDTA. The insect growth regulator diflubenzuron had no effect on mannosyl transferase activity. Dolichol monophosphate and Mg2+ stimulated mannosyl transferase activity. The mannosyl lipid product was identified as mannosyl‐phosphoryl‐dolichol (Man‐P‐Dol). The apparent Km and Vmax values for the formation of Man‐P‐Dol using GDP‐[14C]‐Man while holding dolichol phosphate constant were 2.4 ± 0.9 μM and 9.4 ± 2.3 pmol Man‐P‐Dol·min−1·mg−1 protein, respectively. The apparent Km and Vmax values using dólichol phosphate while holding GDP‐Man constant were 2.2 ± 1.2 μM and 18.5 ± 1.7 pmol Man‐P‐Dol·min−1·mg−1 protein.
Juvadecene: Discovery of a juvenile hormone mimic in the plant, Macropiper excelsum
Authors: Nishida R. , Bowers W. S. , Evans P. H. 
Published: February 2005

AbstractA compound with significant insect juvenile hormone activity was isolated from the plant, Macropiper excelsum. The chemical structure was determined by spectral methods to be 1‐(3,4‐methylenedioxyphenyl)‐trans‐3‐decene(l), and confirmed by synthesis. The hormonally active substance applied topically to last (fifth)‐instar nymphs of the milkweed bug (Oncopeltus fasciatus) induced a supernumerary metamorphosis at 30 μg. Higher doses were toxic.
Induction of cytochrome P‐450‐dependent drug metabolism by juvenile hormone mimics in mammalian cell culture
Authors: Agosin Moises , Repetto Yolanda 
Published: February 2005

AbstractThe monooxygenase activity of fetal hepatocytes in culture shows a differential response toward juvenile hormone I and analogs. Juvenile hormone I, R‐20458, and Methoprene increase the deethyiation of 7‐ethoxyresorufin while not affecting or even inhibiting the N‐demethylation of p‐chloro‐N‐methylaniline. RO‐203600, a 1,3‐benzodioxole‐containing analog, increases both the deethylase and the N‐demethylase, whereas Hydroprene does not affect either activity. The inductive effect with juvenile hormone I is obtained with exposure periods of at least 30 min and is maximum when the concentration of the hormone is 14 μM in the medium. This amount results in the covalent binding to cellular macromolecules of 1.3 × 19−18 moles/cell. The induction requires continuous protein synthesis but RNA synthesis only for a short initial period. It is concluded that juvenile hormone and mimics induce specific cytochrome P‐450 species in fetal liver cells even if the culture conditions are not optimal. The toxicological implications of these results are briefly discussed.
On the relationship between the electroantennogram and simultaneously recorded single sensillum response of the european corn borer, Ostrinia nubilalis
Authors: Nagai Toshio 
Published: February 2005

AbstractElectrical responses of the whole antenna (electroantennogram) and that of the single sensillum trichodeum (electrosensillogram) of male moth of the European corn borer, Ostrinia nubilalis, to their two pheromone components, (Z)‐ and (E)‐11‐tetradecenyl acetates, were recorded simultaneously. The configuration characteristics of both responses resemble each other, and demonstrate an interaction between sensilla trichodea. The typical difference in the response pattern between London (Ontario) and New York strains of this moth seems to be a property of the sensillum trichodeum.
Spontaneous and neurally evoked contractions of visceral muscles in the oviduct of Locusta migratoria
Authors: Lange Angela B. , Orchard Ian , Loughton Barry G. 
Published: February 2005

AbstractThe oviducts of Locusta migratoria are innervated by a pair of nerves which arise from, the seventh abdominal ganglion. A distinctive network of striated muscle fibres occurs in the oviducts. The lateral oviducts and common oviduct consist of an inner circular layer of muscle and an outer longitudinal layer of muscle. At the junction of the lateral and common oviduct an additional thin longitudinal layer is found adjacent to the basement epithelium.The oviducts contracted spontaneously when isolated from the central nervous system. These myogenic contractions took the form of peristaltic contractions in the lateral oviduct, and intermittent phasic‐like contractions of the posterior regions of the lateral oviduct and the common oviduct. These phasic‐like contractions were associated with individual complex potentials recorded extracellularly from the muscle fibres.In locusts that had been interrupted in the process of egg laying, there were large‐amplitude action potentials, firing in a bursting pattern, in the oviducal nerves. These large action potentials were absent in locusts that had not been egg‐laying. These action potentials were associated with both bioelectric potentials and mechanical events in the posterior region of the lateral oviduct and the common oviduct.Electrical stimulation of the oviducal nerve mimicked the effects of spontaneous action potentials, resulting in the appearance of monophasic potentials and contractions. The contractions were graded and dependent upon both frequency and duration of stimulation.It is concluded that the oviducts of Locusta are both myogenic and neurogenic. The role of these contractions in oviposition is discussed.
Evidence for chitin synthesis in an insect cell line
Authors: Marks Edwin P. , Balke Jeffrey , Klosterman Harold 
Published: February 2005

AbstractCells from the continuous MRRL‐CH line derived from embryos of the tobacco hornworm synthesized chitin. Digestion of the washed pellet from [14C]‐N‐acetylglucosamine‐labeled cells by chitinase yielded a water‐soluble labeled compound. The lyophilized residue from the supernatant of the chitin digestion was analyzed by gas‐liquid chromatography as its trimethylsilyl derivative. The major component cochromatographed with derivitized chitobiose. The presence of chitobiose was confirmed by gas chro‐matography‐mass spectrometry. The synthesis of chitin by this cell line is inhibited by diflubenzuron.
Ten generations of Drosophila melanogaster reared axenically on a fatty acid‐free holidic diet
Authors: Rapport E. W. , Stanley‐Samuelson D. , Dadd R. H. 
Published: February 2005

AbstractWild‐type Drosophila melanogaster were axenically raised on a completely synthetic fatty acid‐free diet for at least ten consecutive generations, confirming that these insects do not require dietary polyunsaturated fatty acids. Capillary column gas‐chromatographic analysis of lipids extracted from adults reared on yeast medium showed a peak which cochromatographed with linoleic acid, representing about 1.2% and 0.15% of all fatty acids in phospholipids and triacylglycerols, respectively. In flies reared on the synthetic diet for one generation or for five or more generations, the linoleic acid peak was still present but in about tenfold lower proportions of total fatty acids. This was true of both phospholipid and triglyceride fractions.
Effects of 20‐hydroxyecdysone and tunicamycin on glycoprotein synthesis in an insect cell line
Authors: Jang Eric B. , Klosterman Harold J. , Marks Edwin P. 
Published: February 2005

AbstractTreatment of CH‐MRRL cells with either 20‐hydroxyecdysone or tunicamycin resulted in a decrease in the incorporation of labeled sugars into glycoproteins. This change appears to be largely quantitative, as few qualitative changes in protein bands were apparent as determined by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. Tunicamycin caused a greater change in the amount of labeled sugar incorporated into specific glycoproteins than did 20‐hydroxyecdysone. This was more apparent in [14C]‐mannose‐labeled than in [14C]‐N‐acetylglucosamine‐labeled glycoproteins. Both compounds caused changes in cell surface glycoproteins. These changes are discussed in relation to previous work on binding of lectins to the cell surface and on the mode of action of tunicamycin.
Effects of the venom of Philanthus triangulum F. (Hym. sphecidae) and β‐ and δ‐philanthotoxin on axonal excitability and synaptic transmission in the cockroach CNS
Authors: Piek Tom , Hue Bernard , Pelhate Marcel , David Jonathan A. , Spanjer Willem , Veldsema‐Currie Robin D. 
Published: February 2005

AbstractThis paper provides answers to the questions which of the toxins present in the venom of the wasp Philanthus triangulum may be responsible for the previously reported blockage of transmission through the sixth abdominal ganglion of the cockroach, and whether this may occur by block of synaptic transmission or by affecting axonal exitability. In current clamp experiments the crude venom induces a slight depolarization of the membrane of the giant axon from the sixth abdominal ganglion of the cockroach and a small and irreversible decrease in the amplitude of the action potential. These marginal effects are not seen with relatively high concentrations of the philanthotoxins β‐PTX and δ‐PTX. It appears that neither the crude venom nor the toxins significantly affect the excitability of the cockroach giant axon. At a concentration of 20 μg ml−1 δ‐PTX causes a slowly reversible block of synaptic transmission from the cercal nerve XI to a giant interneuron without any change in resting membrane potential, whereas β‐PTX is inactive. Iontophoretically evoked acetylcholine potentials of the giant neuron are more sensitive to δ‐PTX than excitatory postsynaptic potentials. This suggests that the toxin acts on the postsynaptic membrane.
Metabolism of [3H]‐ecdysone in Schistocerca gregaria; formation of ecdysteroid acids together with free and phosphorylated ecdysteroid acetates
Authors: Gibson J. M. , Isaac R. E. , Dinan L. N. , Rees H. H. 
Published: February 2005

AbstractThe metabolism of [3H]‐ecdysone has been investigated at times of low and high endogenous ecdysteroid tit re, in early and late fifth‐instar Schistocerca gregaria larvae, respectively. Ecdysone‐3‐acetate, 20‐hydroxyecdysone, and 20,26‐dihydroxyecdysone were identified as metabolites in both the free form and as polar conjugates. Comparison of the intact polar conjugates of the ecdysteroid acetates on two HPLC systems with the corresponding authentic compounds indicated that they were 3‐acetylecdysone‐2‐phosphate and 3‐acetyl‐20‐hydroxyecdysone‐2‐phosphate. Other major polar metabolites were identified as ecdysonoic acid and 20‐hydroxyecdysonoic acid. Ecdysone metabolism in fifth‐instar S. gregaria is apparently an age‐dependent process. Early in the instar, excretion of both free and conjugated ecdysteroids, as well as ecdysteroid 26‐acids, occurs. At this stage the level of ecdysteroid acetates in the conjugated (phosphate) form is high, in contrast to the free ecdysteroids, where ecdysone predominates. When the endogenous hormone titre is high, the formation of ecdysteroid acetates is less, the major excreted matabolites at that stage being conjugated 20‐hydroxyecdysone together with ecdysteroid‐26‐acids, but little free ecdysteroids. Acetylation of ecdysone occurs primarily in the gastric caecae. Ecdysone‐3‐acetate (mainly as polar conjugate) is also a major product of ingested ecdysone in early fifth‐instar Locusta migratoria.
Biosynthesis of Drosophila yolk polypeptides
Authors: Minoo Parviz , Postlethwait John 
Published: February 2005

AbstractThe three yolk polypeptides (YPs) of Drosophila are synthesized and secreted by female fat body and ovarian follicle cells, sequestered by pinocytosis into oocytes, and finally deposited into yolk granules. The biosynthesis of the YPs was studied using two‐dimensional gels. Labeling the YPs with [35S]‐cysteine, an amino acid found only near the amino terminus of YP1 and YP2, showed that an amino terminal peptide is removed from YP1 and YP2 shortly after or during translation.Intermediates in YP biosynthesis corresponding in electrophoretic mobility to pancreatic membrane‐processed primary translation products were also detected in a 5‐min pulse label with [35S]‐methionine. Genetic variants that alter YP structure were used to identify which YP precursor comes from which Yp gene. Pulse labeling with [35S]‐methionine revealed that all three YPs becomes more negatively charged, that YP1 and YP2 become heterogeneously charged, and that YP1 gains in apparent molecular weight within 15 min after translation.Injecting female flies with radioiabeled sugars or orthophosphate revealed that the YPs are glycosylated and phosphorylated. Treating hemolymph proteins with phosphatase showed that phosphorylation is responsible for much of the change in charge and increase in molecular weight of the maturing YPs. These experiments with wild‐type flies provide a basis for the analysis of mutations at the Yp genes which alter the structure of individual YPs.
Host‐plant resistance of sorghum: Differential hydrolysis of sorghum pectic substances by polysaccharases of greenbug biotypes (Schizaphis graminum, homoptera: Aphididae)
Authors: Campbell Bruce C. , Dreyer David L. 
Published: February 2005

AbstractPectic substances extracted from different varieties of sorghum are hydrolyzed at differing rates by unfractionated polysaccharases isolated from two biotypes (C, GBC; and E, GBE) of the sorghum pest, Schizaphis graminum (the greenbug). A higher degree of susceptibility of a sorghum variety is associated with a greater rate of hydrolysis of sorghum pectic substances by a greenbug biotype. Increases in the specific activity of polysaccharases on the pectic substances from a resistant sorghum variety are dependent on the duration that a biotype is maintained as a colony on that variety. Polysaccharase activity of GBE on arabinogalactan was significantly greater than GBC. However, there were no differences between the biotypes on the depolymerization of a variety of other plant matrix polysaccharides and a synthetic polysaccharide. The sequence of substrates of increasing refractoriness to hydrolysis are: arabinogalactan < microcrystalline cellulose < xylan < pectin < 2,3‐diacetyl pectin < α‐1,4‐galacturonan. Pectic substances from sorghum varieties resistant to GBC but susceptible to GBE are relatively lower in arabinogalactan with elevated levels of uronic acid (UA) compared to varieties susceptible to both biotypes. A sorghum variety resistant to both GBC and GBE was lowest in levels of arabinogalactan, highest in UA, and highest in fructan content, which in the other varieties occurred only in trace amounts. Pectic composition of rhamnose, xylose, and glucose showed no relationship to resistance. Bound phenolics (potential inhibitors of enzyme activity) were not detected in any of the sorghum pectic substances. The relationship of plant matrix polysaccharides to host‐plant aphid biotype compatibility is discussed.
Sublethal effects of permethrin on the chemical communication system of the pink bollworm moth, Pectinophora gossypiella
Authors: Haynes K. F. , Baker T. C. 
Published: February 2005

AbstractTopically applied sublethal doses of permethrin can interrupt chemical communication between the sexes of Pectinophora gossypiella by affecting both the signaler and the responder. The probability of calling by females is reduced when they are treated with doses of permethrin which are much less than the LD50. Similarly, key stages in the behavioral response of males to sex pheromone are effectively blocked at these low doses. Males recover from these effects 4 days after treatment, but calling by females is still significantly reduced at this time. Chemical control of P. gossypiella populations with permethrin may not be limited to mortality, and potentially includes effective control of behavioral aspects of chemical communication.
Ecdysteroid receptors in a tumorous blood cell line of Drosophila melanogaster
Authors: Dinan Laurence 
Published: February 2005

AbstractThe tumorous Drosophila melanogaster blood cell line BII has been studied for evidence for the presence of ecdysteroid receptors. The [3H]ponasterone A (pon A)* used in this study has been extensively purified, and the location of the tritium in the molecule has been partially determined. BII cells do not metabolise ecdysteroids. Intact cells demonstrate a considerable specific uptake of [3H]pon A which is saturable, apparently showing two specific components: a very high affinity component (KD = 0.3 nM) and a high affinity component (KD = 2 nM). The specific binding of [3H]pon A to whole cells is compatible with unlabelled ecdysteroids, but not with mammalian steroid hormones. The association rate constant (ka) for [3H]pon A was determined to be 3 × 107M−1min−1 at 21 °C, while the dissociation rate constant (kd) for the specifically bound [3H]pon A was found to be 4.4 × 10−3/min. Together, the kinetic rate constants yield a value of 0.15 nM for the KD.The receptors have been partially characterised in a cell‐free extract prepared by sonification of the cells. The optimum pH for extraction and hormone binding is 8.2. Scatchard plots of binding data indicate that the cell‐free extract also contains two high affinity specific binding components (kD = 0.1 nM and KD = 1 nM). The hgih affinity binders are macromolecular, as shown by chromatography on Sephadex G‐25, and are susceptible to protease digestion, heat, and treatment with N‐ethylmaleimide. Sucrose density centrifugation of the labelled receptor shows one peak at approximately 6S. The stability of the receptor preparation has been studied and conditions have been empirically determined (10% w/v sucrose, 25 mM dithioerthreitol, and 10 mM citrate), whereby the binding capacity of the unlabelled receptor is stable for at least 8 weeks if frozen at −20°C.
Physiological investigation on the role of the innervation in the regulation of the prothoracic gland in Periplaneta americana
Authors: Richter Klaus 
Published: February 2005

AbstractUnder in vitro conditions the prothoracic gland nerve of the last larval instar of Periplaneta americana shows the same efferent nervous activity as under in situ conditions–ie, low activity at the 9th day and high activity at the 20th day of the molting interval. Isolation of the prothoracic ganglion from the subesophageal ganglion provokes an increase in this nerve activity, suggesting an inhibitory effect of the subesophageal ganglion on prothoracic gland nerve activity in vivo. Only in 20‐day‐old larvae does electrical stimulation of isolated prothoracic glands in vitro via the gland nerve result in a slightly increased release of ecdysteroids from the gland. This effect could not be influenced by different lengths of stimulation periods. Denervation of the prothoracic gland by transection of the gland nerve on the 13th day of the molting interval results in a complete abolition of the first peak of ecdysteroid production in the gland but has no influence on the occurrence and the amount of the main ecdysteroid peak just before the molt. The results suggest the participation of nervous activity in special periods of prothoracic gland regulation in the cockroach.
Isolation and characterization of highly purified mosquito oostatic hormone
Authors: Borovsky Dov 
Published: February 2005

AbstractOostatic hormone, the hormone that inhibits vitellogenesis in mosquitoes, was purified 7,000‐fold with a recovery of 70% from the ovaries of the mosquito Aedes aegypti. The purification procedure included heat treatment and chromatography on ion exchange and gel filtration columns. The hormone is a small peptidelike molecule of molecular weight 2,200 at pH 4.5, which aggregates into larger molecular species of trimer and octamer at pH 7.0 as determined by gel filtration. The hormone is positively charged at pH 7.8 and has a low Rf at pH 9.4 on disc gel electrophoresis.Injection of purified oostatic hormone (9 ng) into female mosquitoes inhibited yolk deposition and vitellogenin synthesis. Activity of the oostatic hormone in the mosquito ovary increased rapidly following blood feeding and reached a maximum after 48 h. Oostatic hormone of A. aegypti injected into autogenous Aedes taeniorhynchus inhibited egg development. Repeated injections of dilute oostatic hormone at 24 h intervals partially arrested egg development, resulting in 60% reduction in the number of eggs laid. This hormone does not block release of egg development neurosecretory hormone (EDNH) from the mosquito brain but rather appears to act on the ovary.