bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipophorin in the larval and adult stages of Musca domestica
Authors: De Bianchi Antonio G. , Capurro Margareth De L. , Marinotti Osvaldo 
Published: February 2005

AbstractThe major Musca domestica hemolymph lipoprotein, lipophorin, was purified from larval and from adult animals. The housefly lipophorin is composed of two apoproteins, apolipophorin I (Mr ∽ 253,000) and apolipophorin II (Mr ∽ 85,000). The lipophorin contains about 3.9% carbohydrates and reacts positively with concanavalin A. The density of larval lipophorin is equal to 1.152 g/ml and of adult lipophorin to 1.106 g/ml. The amount of lipophorin per animal increases during the larval stage, is constant during pupal stage, and suffers a great reduction at the pharate adult stage. The amount of lipophorin remains stable during the whole first gonotrophic cycle of the housefly. Lipophorin is not detected in the eggs of this insect.
Purification and properties of a factor from insect hemolymph that promotes multicellular vesicle formation in vitro
Authors: Ferkovich S. M. , Oberlander H. , Dillard C. , Leach C. E. 
Published: February 2005

AbstractA vesicle promoting factor (VPF) in an insect cell line IAL‐TND1 was partially purified from larval hemolymph of the cabbage looper, Trichoplusia ni Hübner. The polypeptide had a molecular weight estimated to be between 20.5 kD and 37.5 kD by gel permeation, 22.5 kD by the Ferguson plot on nondenaturing polyacrylamide gel electrophoresis, and 16.88 kD on sodium dodecyl sulfate PAGE. VPF fractions were isolated from hemolymph by gel permeation on Fractogel® and were either subjected to chromatofocusing or preparative isoelectric focusing. After the gel permeation step, the VPF polypeptide was highly unstable during the separation and storage. The two active fractions from the isoelectric separations had isoelectric points of 6.21 and 6.36 and had specific activities of 34 and 32 vesicles/μg protein per test culture chamber. The percentage of total larval equivalent hemolymph proteins found in these fractions was less than 1%. Chromatofocusing technique also yielded an active fraction containing a single band on nondissociating electrophoresis that had VPF activity. This band had an isoelectric point of 6.60 but had a lower specific activity of three vesicles/μg protein in the VPF cell bioassay.
Evidence for a sex pheromone metabolizing cytochrome P‐450 mono‐oxygenase in the housefly
Authors: Ahmad Sami , Kirkland Kenneth E. , Blomquist Gary J. 
Published: February 2005

AbstractDirect evidence is presented for the role of a cytochrome P‐450 monooxygenase (called mixed‐function oxidase, or polysubstrate mono‐oxygenase, PSMO) in the metabolism of the sex pheromone (Z)‐9‐tricosene to its corresponding epoxide and ketone in the housefly. A secondary alcohol, most likely an intermediate in the conversion of the alkene to the ketone, was also tentatively identified. The results of in vivo and in vitro experiments showed that the PSMO inhibitors, piperonyl butoxide (PB) and carbon monoxide, markedly inhibited the formation of epoxide and ketone from (9,10‐3H) (Z)‐9‐tricosene. An examination of the relative rates of (Z)‐9‐tricosene metabolism showed that males exhibited a higher rate of metabolism than females with the antennae of males showing the highest activity of any tissue/organ examined. The major product from all tissues/organs was the epoxide. Data from experiments with subcellular fractions showed that the microsomal fraction had the majority of enzyme activity, which was strongly inhibited by PB and CO and required NADPH and O2for activity. A carbon monoxide difference spectrum with reduced cytochrome showed maximal absorbance at 450 nm and allowed quantification of the cytochrome P‐450 in the microsomal fraction of 0.410‐nmol cytochrome P‐450 mg−1protein. Interaction of (Z)‐9‐tricosene with the cytochrome P‐450 resulted in a type I spectrum, indicating that the pheromone binds to a hydrophobic site adjacent to the heme moiety of the oxidized cytochrome P‐450.
Pharmacology of [3H]mianserin binding in the nerve cord of the American cockroach, Periplaneta americana
Authors: Minhas Nailah , Gole John W. D. , Orr Gregory L. , Downer Roger G. H. 
Published: February 2005

AbstractThe binding of [3H]mianserin to homogenates of cockroach nerve cord was investigated, using a centrifugal binding assay. Nonspecific binding was defined as binding in the presence of 0.1 μM phentolamine. Specific binding was saturable and indicated a high affinity site (KD = 39.6 nM and Bmax = 0.8 fmol μGg−1) and a low affinity site (KD = 648.9 nM and Bmax = 5.9 fmol μg−1). The binding was reduced or abolished by heat, detergents, trypsin and HgCl2. Incorporation of CaCl2 or NaCl into the medium reduced binding in a dose‐dependent fashion, whereas MgCl2 and NaF inhibited binding in a biphasic manner. The stable GTP analog, 5′‐guanylylimidodiphosphate, reduced the high affinity binding at 10 μM. Phentolamine, D,L‐octopamine, demethylchlordimeform (DCDM), clonidine, and D,L‐synephrine are effective displacers of [3H]mianserin‐binding, whereas dopamine, acetylcholine, serotonin (5‐HT), and histamine show poor or no displacement. The pharmacological properties of octopamine‐sensitive adenylate cyclase stimulation in cockroach nerve cord are similar to those of [3H]mianserin‐binding.
Cell culture techniques for studying insect cuticle
Authors: Marks Edwin P. , Ward Gordon B. 
Published: February 2005

AbstractEvidence that biosynthetic pathways critical to the formation of insect cuticle are retained in continuous insect cell lines opens new possibilities for research on the cuticle system. Recent findings indicate that chitin, molting hormone, and catecholamines are all produced by a vesicle cell line derived from embryos of the cockroach Blattella germanica. The chitin that is formed by this cell line is particulate and does not show the characteristic featherlike crystalline structure found in mature cuticle. The molting hormone is produced as ecdysone and is released into the culture medium. The addition of 20‐hydroxyecdysone to the cultures increases the production of chitin fourfold. These responses are similar to those found in insect organ cultures.
Isolation and fluorescence studies on a lipophorin from the weevil diaprepes abbreviatus
Authors: Shapiro Jeffrey P. 
Published: February 2005

AbstractLipophorin was isolated from larvae of a root weevil, Diaprepes abbreviatus (Coleoptera: Curculionidae), using density gradient ultracentrifugation. D. abbreviatus lipophorin contained two apoproteins, apolipophorin‐I (Mr = 226,000) and apolipophorin‐II (Mr = 72,100) and had a density of 1.08. Relative to other larval lipophorins, D. abbreviatus lipophorin contained little cysteine (determined as cysteic acid) and methionine. Fluorescence spectroscopy of intrinsic tyrosine and tryptophan residues excited at 290 nm revealed a single broad emission peak at 330 nm. Upon denaturing and delipidating lipophorin in guanidine HCl, this peak resolved into two peaks with maxima at 305 and 350 nm. Excitation spectra suggested that the two peaks were due to tyrosine and tryptophan, respectively. Fluorescence quenching agents, iodide and acrylamide, were used to determine accessibility of tyrosine and tryptophan residues to the aqueous environment. Iodide, a polar quenching agent, did not quench fluorescent emission from native lipophorin; quenching by iodide increased to moderate levels when lipophorin was denatured in guanidine HCl. Acrylamide quenched the fluorescence of native lipophorin moderately and very efficiently quenched fluorescence of denatured lipophorin. No difference was observed between fluorescence quenching of denatured vs. denatured and delipidated lipophorin by either iodide or acrylamide.
Subcellular distribution and activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase in the southern armyworm, Spodoptera eridania
Authors: Ahmad Sami , Pritsos Chris A. , Bowen Susan M. , Heisler Charles R. , Blomquist Gary J. , Pardini Ronald S. 
Published: February 2005

AbstractIn mid‐fifth‐instar larvae of the southern armyworm, Spodoptera eridania, the subcellular distribution of four antioxidant enzymes—superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPOX), and glutathione reductase (GR)—were examined. Two‐thirds (4.26 units ·mg protein−1) of the SOD activity was found in the cytosol, and one‐thirds (2.13 units ·mg protein−1) in the mitochondria. CAT activity was unusually high and not restricted to the microsomal fraction where peroxisomes are usually isolated. The activity was distributed as follows: cytosol (163 units) mitochondria (125 units) and microsomes (119 units). Similar to CAT, the subcellular compartmentalization of both GPOX and GR was unusual. No activity was detected in the cytosol, but in mitochondria and microsomes, GR levels were 5.49 and 3.09 units. Although GPOX activity exhibited 14–16‐fold enrichment in mitochondria and microsomes, respectively, over the 850g crude homogenate, the level was negligible (mitochondria = 1.4 × 10−3 units; microsomes = 1.6 × 10−3 units), indicating that this enzyme is absent. The unusual distribution of CAT has apparently evolved as an evolutionary answer to the absence of GR from the cytosol, and the lack of GPOX activity.
Oostatic hormone inhibits biosynthesis of midgut proteolytic enzymes and egg development in mosquitoes
Authors: Borovsky Dov 
Published: February 2005

AbstractInjection of partially purified oostatic hormone (0.7 μg) into female Aedes aegypti inhibited egg development, proteolytic enzyme activity, and blood digestion in the midgut, whereas control injections of saline or insulin chain A (0.7 μg) did not affect these processes. Oostatic hormone given by enema, on the other hand, did not inhibit proteolytic enzyme activity, indicating that the hormone acts outside the midgut. A single injection of oostatic hormone (0.7 μg) caused a 1.7–1.5‐fold reduction in activity of trypsinlike enzymes during blood digestion, with a 10‐h delay in peak activity.Using [1,3‐3H]diisopropylfluorophosphate (DFP) in the presence of 8 mM tosylamide‐2‐phenylethyl chloromethyl ketone, the synthesis of trypsinlike derivatives was followed in the midgut of female A. aegypti. A 4‐fold reduction in [1,3‐3H]diisopropylphosphoryl‐trypsinlike derivatives was noted after oostatic hormone treatment. Several isozymes that are normally synthesized were absent in the presence of DFP, as assessed by polyacrylamide gel electrophoresis. Injection of oostatic hormone into decapitated and ovariectomized females that did not synthesize ecdysteroids inhibited trypsinlike enzyme synthesis and blood digestion in the midgut, indicating that oostatic hormone inhibits the midgut cells and not the ovary or the brain's endocrine system.Comparison between oostatic hormone and soybean trypsin inhibitor indicated that the former inhibited trypsin synthesis whereas the latter inhibited trypsin activity. A. aegypti oostatic hormone is not species specific and injections of the hormone into Culex quinquefasciatus, Culex nigripalpus, and Anopheles albimanus caused inhibition of egg development, blood digestion, and synthesis of trypsinlike enzymes. A direct relation between oostatic hormone synthesis and the regulation of trypsinlike activity in the midgut is proposed.
Uptake of cholesterol and cholestanol by the intestine, hemolymph, and fat body of Heliothis zea
Authors: Kuthiala Arun , Ritter Karla S. 
Published: February 2005

AbstractThe effect of the concentration and structure of dietary sterol on its uptake and distribution in the intestine, hemolymph and fat body was studied in sixth‐instar larvae of Heliothis zea. When cholesterol (cholest‐5‐en‐3β‐ol) was inoculated per os into the foregut of larvae, it was rapidly taken up by the intestine. Some of the dietary sterol then passed into the hemolymph, primarily via the midgut, during at least the first 9 h after inoculation, while at least 7% of the dose remained associated with the intestine. The amount of dietary sterol per 0.10 g of hemolymph increased until it reached 3–6% of the dose after 9 h. The amount of sterol per 0.10 g of the fat body increased to as much as 5% of the dose after 10 h. As the concentration of sterol in the dose increased from 0.3 to 15 μg/4 μl, the amount of sterol associated with the intestine, hemolymph, and fat body also increased. When cholesterol was inoculated intrahemocoelically, instead of per os, the amount of sterol in the hemolymph decreased, for at least the first 8 h after inoculation, and may have been absorbed, at least in part, by the intestine. The absence of a double bond in cholestanol (5α‐cholestan‐3β‐ol) had no significant effect, at least 5 h after inoculation, on the uptake and distribution of this sterol in the intestine, hemolymph, and fat body of the larva. The results of this study indicate that although larvae of H. zea fed cholestanol have a slower rate of growth than those fed cholesterol, this may be due to differences in the utilization of the two sterols rather than to differences in their uptake by the tissues.
Esterification of cholesterol and cholestanol in the whole body, tissues, and frass of Heliothis zea
Authors: Kuthiala Arun , Ritter Karla S. 
Published: February 2005

AbstractThe quantity of free and esterified sterols in the whole body, intestine, hemolymph, fat body, and frass of 6th‐instar larvae of H. zea, fed cholesterol or cholestanol, was measured in order to determine if there was a difference in the utilization of these two molecules. The principal sterol in the tissues of the larvae was cholestanol or cholesterol, when they were fed diet containing these two molecules, respectively; there was little, if any, metabolism of dietary cholestanol to cholesterol. There was little or no difference in the amount of total sterol in the whole body, tissues, or frass of larvae fed the two different diets, indicating that the absence of a Δ5‐bond in cholestanol does not prevent the uptake or distribution of this sterol to various tissues. However, the relative percentage of steryl ester was significantly higher in prepupae reared on a diet containing cholestanol instead of cholesterol (6–7‐, 4‐, 13‐, 4‐, and 2‐fold increase, for the whole body, intestine, hemolymph, fat body, and frass, respectively). The average percentage of total sterol that was esterified in the tissues was greater in the fat body (10.8 ± 15.4 and 44.2 ± 12.3%, respectively, for larvae fed cholesterol and cholestanol) than in the hemolymph (0.5 ± 0.1 and 6.3 ± 0.8%) and intestine (1.2 ± 0.1 and 4.7 ± 1.1%). The percentage of sterol that was esterified in the frass of larvae was large (26.9 ± 3.7 and 48.2 ± 0.5%, respectively, for larvae fed cholesterol and cholestanol). Therefore, the fact that larvae of H. zea fed cholestanol, instead of cholesterol, contain this saturated molecule as their principal tissue sterol and preferentially esterify it may explain, at least in part, why their rate of growth on cholestanol is slower than on cholesterol.
20‐Hydroxyecdysone and ovarian maturation in the firebrat Thermobia domestica (Thysanura: Lepismatidae)
Authors: Bitsch C. , Bitsch J. 
Published: February 2005

AbstractThe effects of 20‐hydroxyecdysone on ovary maturation in the firebrat Thermobia domestica were investigated by in vivo injections of different doses of the hormone on various days of the reproductive cycle. Several females were neck‐ligated or treated with precocene II before injection. Experiments were also performed on ovarioles incubated in vitro. It was demonstrated that 20‐hydroxyecdysone has direct and dose‐dependent effects on the ovary, inducing growth of all the previtellogenic follicles whatever the day of the reproductive cycle, except at times when the ovaries contain follicles undergoing choriogenesis. The major effect of the hormone is the stimulation of young‐follicle formation in the anterior part of the previtellarium and the accelerated growth of a set of basal previtellogenic follicles, which reach the critical size required for yolk deposition. However, 20‐hydroxyecdysone did not induce cellular differentiation, in particular, the enlargement of the perioocyte space and the development of oocyte microvilli, which normally occur before yolk precursor incorporation. The present results give a better understanding of the temporal relationships between molting and reproductive cycles and also explain the periodicity of ovarian maturation.
Yolk hydrolase activities associated with polypeptide and oligosaccharide processing of Blattella germanica vitellin
Authors: Purcell John P. , Kunkel Joseph G. , Nordin John H. 
Published: February 2005

AbstractVarious aspects of the processing of Blattella germanica vitellin (Vt) in the oocyte and egg have been investigated. Employing subunit specific antibodies, the precursor product relationships among the subunits of this Vt have been determined. After endocytosis of Vt by the oocyte, the Mr 160,000 subunit Vt is cleaved to products of Mr 95,000 and Mr 50,000. In association with an unprocessed Mr 102,000 peptide, these form the subunits of the Vt of freshly ovulated eggs. Between 4 and 5 days post ovulation (at 30°C), all three subunits of Vt are again processed proteolytically before use by the embryo. Although Vt's high mannose‐type oligosaccharides are trimmed during embryogenesis, their modification occurs subsequent to the day 4–5 proteolysis, precluding the possibility that changes in oligosaccharide content or structure contribute to regulating this second proteolytic event. Although the predominant oligosaccharide of Vt is Man9GlCNAc2, the Mr 50,000 subunit of egg‐borne Vt contains a much higher proportion of Man6GlCNAc2 than the other two subunits; therefore, this portion of the precursor vitellogenin must be more accessible to the processing mannosidases of the endoplasmic reticulum during its biosynthesis. A microtechnique for aspirating the yolk from individual eggs in an oothecapermits its isolation free of contamination by embryonic tissue. With this procedure, the specific activity profiles of exo‐α‐mannosidase, exp‐β‐N‐acetylglucosaminidase, α‐glucosidase and acid phosphatase were monitored during the first 6 days after ovulation, and some of their properties were also determined. Expression of the acid phosphatase and exo‐β‐N‐acetyl‐glucosaminidase activities coincide with the day 4–5 proteolysis, while α‐mannosidase remains relatively constant throughout the first 6 days. Functions for these enzymes and the oligosaccharides of Vt during Vt storage and utilization are proposed.
Quinone methides—and not dehydrodopamine derivatives—as reactive intermediates of β‐sclerotization in the puparia of flesh fly Sarcophaga bullata
Authors: Sugumaran Manickam 
Published: February 2005

AbstractCuticular phenoloxidase(s) from Sarcophaga bullata larvae oxidized a variety of o‐diphenolic compounds. While catechol, 3,4‐dihydroxybenzoic acid, dopa, dopamine, and norepinephrine were converted to their corresponding quinone derivatives, other catechols such as 3,4‐dihydroxyphenylacetic acid, 3,4‐dihydroxyphenethyl alcohol, 3,4‐dihydroxyphenyl glycol, 3,4‐dihy‐droxymandelic acid, and N‐acetyldopamine were oxidized to their side‐chain oxygenated products. In addition, the enzyme‐catalyzed oxidation of the latter group of compounds accompanied the formation of colorless catecholcuticle adducts consistent with the operation of β‐sclerotization. Radioactive trapping experiments failed to support the participation of 1,2‐dehydro‐N‐acetyldopamine as a freely formed intermediate during phenoloxidase‐mediated oxidation of N‐acetyldopamine. When specifically tritiated substrates were provided, cuticular enzyme selectively removed tritium from [7‐3H]N‐acetyldopamine and not from either [8‐3H] or [ring‐3H]N‐acetyldopamine during the initial phase of oxidation. The above results are consistent with the generation and subsequent reactions of quinone methides as the initial products of enzyme‐catalyzed N‐acetyldopamine oxidation and confirm our hypothesis that quinone methides and not 1,2‐dehydro‐N‐acetyldopamine are the reactive intermediate of β‐sclerotization of sarcophagid cuticle. Quinone methide sclerotization resolves a number of conflicting observations made by previous workers in this field.
Inhibition of ecdysteroid production in nymphs of Rhodnius prolixus treated with ethoxyprecocene II
Authors: Garcia Eloi S. , De Azambuja Patricia , Feder Denise , Bowers William S. 
Published: February 2005

AbstractRhodnius prolixus nymphs fed 7‐ethoxy‐6‐methoxy‐2,2‐dimethylchromene (ethoxyprecocene II, EPII) show a variety of responses, including precocious molting to diminutive adults, severe retardation of molting, or a condition of permanent ecdysial stasis. The latter two conditions are reversible by subsequent treatment with 20‐hydroxyecdysone. Ecdysteroid titers in the hemolymph of individual insects, determined by radioimmunoassay (RIA), show that the ecdysteroid cycle in nymphs undergoing precocious metamorphosis is similar to that of untreated fifth stage nymphs during normal imaginal molting. Nymphs in ecdysial stasis, following EPII treatment, were found to have very low ecdysteroid titers. Analysis of ecdysteroid synthesis by the prothoracic glands (PG), cultured in vitro, showed that: 1) only traces of ecdysteroid were detectable in PG from nymphs treated in vivo with EPII; 2) the PG from untreated nymphs incubated in culture medium with EPII possessed significantly lower ecdysteroid synthesis compared with controls. These studies sought to determine if the inhibition of ecdysteroid biosynthesis observed in Rhodnius, following exposure to EPII in vivo and in vitro, is due to a direct action on the PG or result as an indirect effect perhaps mediated by the neuroendocrine system.
Peptidoglycan fragments elicit antibacterial protein synthesis in larvae of Manduca sexta
Authors: Kanost Michael R. , Dai Wei , Dunn Peter E. 
Published: February 2005

AbstractIn several insect species, serum lysozyme and antibacterial peptide concentration increases after injection of bacteria and other foreign substances. The purpose of this study was to characterize the specificity of this induction in the tobacco hornworm, Manduca sexta. By 48 h after injection of killed bacteria, lysozyme activity was approximately tenfold greater than in untreated insects. This maximal response was observed after injection of every bacterial species tested and after injection of purified cell walls of Micrococcus luteus. A variety of acellular particles, soluble molecules, and bacterial cell wall components were either poor lysozyme inducers or elicited no change in lysozyme concentration. The polysaccharide zymosan from yeast cell walls was a moderate lysozyme inducer. Peptidoglycan from M. luteus cell walls was found to induce lysozyme to a level as great or greater than whole cell walls. Small fragments of peptidoglycan generated by hen egg white lysozyme digestion were isolated, partially characterized, and shown to be good inducers of lysozyme as well as other antibacterial peptides. It appears that peptidoglycan provides a signal that initiates antibacterial responses in the insect.