bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assembly and secretion of lipophorin by the larval fat body of the southwestern corn borer, Diatraea grandiosella: An in vitro study
Authors: Shelby Kent S. , Chippendale G. Michael 
Published: February 2005

AbstractThe synthesis, processing, and secretion of lipophorin by the larval fat body of the southwestern corn borer, Diatraea grandiosella, was examined using in vitro techniques. Pulse‐labeling of lipophorin with [35S]methionine showed that apolipophorin‐I and ‐II were each synthesized and secreted from the fat body into Grace's medium with an intracellular transit time of about 45 min. Secretion of the apolipoproteins from the fat body became insensitive to the presence of monensin, which disrupts protein processing in the Golgi complex, at 30 min, indicating that most of the pulse‐labeled apolipoprotein has transited the Golgi complex by this time. Three inhibitors of protein processing, carbonylcyanide m‐chlorophenyl hydrazone, monensin, and brefeldin A, inhibited secretion of lipophorin into medium. Puromycin treatment did not appear to result in the secretion into the medium of lipophorin particles containing incomplete translation products of apolipophorin‐I or ‐II. Incubation of fat bodies with [3H]oleate resulted in the secretion of lipophorin containing [3H]glycerides, a process that was inhibited by cycloheximide, puromycin, and monensin, indicating that apolipoprotein synthesis is required for secretion of [3H]glyceride on nascent lipophorin particles. In contrast, suramin, which has been shown to block the binding of lipophorin to plasma membrane receptors, inhibited the synthesis and secretion of lipophorin, but it did not appear to inhibit the transfer of [3H]lipid from the fat body to lipophorin. Inhibitors of protein synthesis and processing, therefore, can be used to distinguish between secretion of lipophorin‐associated lipids and secretion of lipids mediated by the lipid‐transfer particle outside the plasma membrane of the fat body.
Generation of superoxide anion radical by α‐terthienyl in the anal gills of mosquito larvae Aedes aegypti: A new aspect in α‐terthienyl phototoxicity
Authors: Nivsarkar Manish , Kumar G Pradeep , Laloraya Malini , Laloraya Manmohan M. 
Published: February 2005

AbstractThe present study documents that the secondary plant metabolites, especially α‐terthienyl, exert phototoxic action through inhibition of certain enzymes and generation of singlet oxygen. Some of the reports have emerged exhibiting involvement of free radical generation in vitro by α‐terthienyl. We provide evidence for the generation of a free radical viz., superoxide anion radical, by α‐terthienyl employing spin‐trapping techniques, probably due to the extension of the latter reaction. On the basis of this observation the phototoxic action of α‐terthienyl on Aedes aegypti larvae is explained. © 1992 Wiley‐Liss, Inc.
Studies on the enzymes involved in puparial cuticle sclerotization in Drosophila melanogaster
Authors: Sugumaran Manickam , Giglio Linda (Burgio) , Kundzicz Heather , Saul Steven , Semensi Victor 
Published: February 2005

AbstractThe properties of cuticular enzymes involved in sclerotization of Drosophila melanogaster puparium were examined. The cuticle‐bound phenoloxidase from the white puparium exhibited a pH optimum of 6.5 in phosphate buffer and oxidized a variety of catecholic substrates such as 4‐methylcatechol, N‐β‐alanyldopamine, dopa, dopamine, N‐acetyldopamine, catechol, norepinephrine, 3,4‐dihydroxyphenylglycol, 3,4‐dihydroxylbenzoic acid, and 3,4‐dihydroxyphenylacetic acid. Phenoloxidase inhibitors such as potassium cyanide and sodium fluoride inhibited the enzyme activity drastically, but phenylthiourea showed marginal inhibition only. This result, coupled with the fact that syringaldazine served as the substrate for the insoluble enzyme, confirmed that cuticular phenoloxidase is of the “laccase” type. In addition, we also examined the mode of synthesis of the sclerotizing precursor, 1,2‐dehydro N‐acetyldopamine. Our results indicate that this catecholamine derivative is biosynthesized from N‐acetyldopamine through the intermediate formation of N‐acetyldopamine quinone and N‐acetyldopamine quinone methide as established for Sarcophage bullata [Saul, S. and Sugumaran, M., F.E.B.S. Letters 251, 69–73 (1989)]. Accordingly, successful solubilization and fractionation of cuticular enzymes involved in the introdution of a double bond in the side chain of N‐acetyldopamine indicated that they included o‐diophenoloxidase, 4‐alkyl‐o‐quinone: p‐quinone methide isomerase, and N‐acetyldopamine quinone methide: dehydro N‐acetyldopamine isomerase and not any side chain desaturase. © 1992 Wiley‐Liss, Inc.
Blue lipophorin from Podisus maculiventris
Authors: Haunerland Norbert H. , Ortego Felix , Strausfeld Camilla M. , Bowers William S. 
Published: February 2005

AbstractA chromoprotein responsible for the blue coloration of the hemolymph in the spined soldier bug, Podisus maculiventris (Say), was isolated and identified as lipophorin. With the exception of its blue color the lipoprotein shares similar molecular characteristics with the hemolymph lipophorins of other Hemipterans and insects of several different orders. Its ability to carry a blue chromophore, biliverdin IX γ, adds a new feature to this multifunctional lipoprotein. © 1992 Wiley‐Liss, Inc.
Infradian cycles of oxygen consumption in diapausing pupae of the flesh fly, Sarcophaga crassipalpis, monitored by a scanning microrespirographic method
Authors: Sláma Karel , Denlinger David L. 
Published: February 2005

AbstractFine details of the infradian O2 consumption cycles that characterize pupal diapause in flesh flies have been monitored by a newly designed microrespirographic method coupled with an electronically regulated O2 generator. During the 4–5 days between the peaks of elevated O2 consumption the diapausing pupae maintained a very low and fairly constant respiratory rate (13 μl O2 · g−1 · h−1). During the intercalated peaks of increased respiratory metabolism, which lasted an average of 33.6 h at 24–27°C, the average maximum rate of O2 consumption was 86.9 μl · g−1 · h−1, a value 6.7 times higher than the interpeak values. The respiratory peaks started abruptly in some cases, while the decline was consistently gradual. During the periods between the peaks there were no discontinuous bursts of CO2 release, a feature common to diapause in many other insects. Diapause was characteristically terminated during a peak of the O2 consumption cycle. At diapause termination O2 consumption remained at the maximum values of the peak for many hours and then gradually increased to levels characteristic of nondiapause development. © 1992 Wiley‐Liss, Inc.
Oral toxicity to flesh flies of a neurotoxic polypeptide
Authors: Zlotkin Eliahu , Fishman Lena , Shapiro Jeffrey P. 
Published: February 2005

AbstractAn insect selective neurotoxic polypeptide from venom of the scorpion Androctonus australis (AalT, Mr 8,000) was shown to cross the midgut of the flesh fly Sarcophaga falculata, using assays of oral toxicity, column chromatography, and microscopic autoradiography of the native and radioiodinated toxin. AalT induced paralysis of flies within 1–2 h after oral administration, with a lethal dose (LD50) of 10 μg/100 mg of body weight. Oral toxicity was about 0.14% of toxicity by injection. Hemolymph collection 70–85 min after feeding flies with [125l]AalT showed that 5% of ingested radioactivity appeared in hemolymph. Most of this represented degradation products, but included about 0.3% of the chromatographically intact toxin. In contrast, hemolymph of identically treated lepidopterous larvae (Manduca, Helioverpa [=Heliothis]) contained degradation products but no intact toxin. [125l]AalT was shown to cross the midgut of Sarcophaga through a morphologically distinct segment of the midgut previously shown to be permeable to a cytotoxic, positively charged polypeptide of similar molecular weight. These results suggest that Sarcophaga midgut contains a morphologically and functionally distinct segment that transports small peptides, and that employment of neurotoxic polypeptides for insect control may be feasible. Activity might be greatly improved through modification and metabolic stabilization of active peptides. © 1992 Wiley‐Liss, Inc.
A protein from Daudi cell line conditioned medium induces ovarian dysgenesis in Drosophila melanogaster
Authors: Richard‐Mercier Noëlle , Thomas‐Orillard Michèle , Morinière Madeleine , Porcheron Patrick , Soyez Daniel , Fellous Marc 
Published: February 2005

AbstractFrom a medium in which Daudi cells had been grown, we isolated by HPLC a protein that caused ovarian abnormalities in adult females of Drosophila melanogaster when injected into preblastoderm embryos. This protein, whose apparent Mr is between 30,000 and 50,000, was found to be a moderately polar compound which is heat stable and whose activity is destroyed by acidification. The protein is characteristic of medium conditioned from Daudi cells. © 1992 Wiley‐Liss, Inc.
Invertebrate neuropeptide processing: Partial characterization of peptidylglycine α‐amidating monooxygenase in the tobacco hornworm, Manduca sexta
Authors: Bernasconi Paul , Li Jorge P. , Reagan Jeff D. , Kramer Steven J. 
Published: February 2005

AbstractA peptidylglycine α‐amidating monooxygenase (PAM) has been characterized in the tobacco hornworm Manduca sexta. Although such enzymes have been well studied in vertebrates, their presence in invertebrates has not been reported. PAM activity was measured in several insect tissues. The highest specific activity was found in the brain. In this organ, PAM activity was high during the larval stages, but low at the end of metamorphosis. Copper, oxygen, and ascorbate were required for activity. Evidence that 2, 4, 5‐trihydroxyphenylalanine may be involved in PAM activity is presented. © 1992 Wiley‐Liss, Inc.
Prospects of using Drosophila for insect neuroendocrine research
Authors: Segal Daniel 
Published: February 2005

AbstractClassical and in vitro approaches for the analysis of the molecular components of neuroendocrine systems often disrupt their close interaction with other bodily systems, which is a crucial aspect of their function in vivo. “Genetic dissection” is an alternative, noninvasive approach which involves the systematic generation of mutations in individual genes, followed by in vivo analysis of the phenotypic effects of altering a single protein at a time avoiding extraneous disruptions. Among insects Drosophila melanogaster is the most suitable model for this approach. This paper explores the application of genetic and molecular techniques available in Drosophila for studying its neuroendocrine system with special emphasis on the production of ecdysone and juvenile hormone.Strategies are described for the generation and identification of endocrine mutations, especially those affecting hormone synthesis and regulation. Once identified by a specific mutation, a gene in Drosophila can be cloned either by chromosomal microdissection and “chromosomal walk” or by transposon tagging. Methods for molecular analysis of the structure and function of a cloned gene and of the protein it encodes are available for further study.Alternatively, a gene can be cloned using heterologous DNA probes or oligonucleotides designed according to the amino acid sequence of a protein. Genes may also be cloned via their pattern of expression using stage‐ or tissue‐specific cDNA libraries or through transposon‐mediated “enhancer detection.” Anti‐sense RNA, the replacement of the gene by in vitro manipulated versions, or mutagenesis of its endogenous copies can then be used for studying its function in vivo.Information about endocrine genes in Drosophila as well as material such as cloned genes and antibodies should be useful for the analysis of endocrine systems in other insects which are not amenable to genetic manipulations. Such information should be helpful in designing novel means for pest control based on the specific intervention with endocrine systems regulating insect development and reproduction. © 1993 Wiley‐Liss, Inc.
Chitin synthesis and degradation as targets for pesticide action
Authors: Cohen Ephraim 
Published: February 2005

AbstractVarious pesticides are being used to destabilize, perturb, or inhibit crucial biochemical and physiological targets related to metabolism, growth, development, nervous communication, or behavior in pestiferous organisms. Chitin is an eukaryotic extracellular aminosugar biopolymer, massively produced by most fungal systems and by invertebrates, notably arthropods. Being an integral supportive component in fungal cell wall, insect cuticle, and nematode egg shell, chitin has been considered as a selective target for pesticide action. Throughout the elaborate processes of chitin formation and deposition, only the polymerization events associated with the cell membrane compartment are so far available for chemical interference. Currently, the actinomycetes‐derived nucleoside peptide fungicides such as the polyoxins and the insecticidal benzoylaryl ureas have reached commercial pesticide status. The polyoxins and other structurally‐related antibiotics like nikkomycins are strong competitive inhibitors of the polymerizing enzyme chitin synthase. The exact biochemical lesion inflicted by the benzoylaryl ureas is still elusive, but a post‐polymerization event, such as translocation of chitin chains across the cell membrane, is suggested.Hydrolytic degradation of the chitin polymer is essential for hyphal growth, branching, and septum formation in fungal systems as well as for the normal molting of arthropods. Recently, insect chitinase activity was strongly and specifically suppressed by allosamidin, an actimomycetes‐derived metabolite. In part, the defense mechanism in plants against invasion of pathogens is associated with induced chitinases. Chitin, chitosan, and their oligomers are able to act as elicitors which induce enhanced levels of chitinases in various plants. Lectins which bind to N‐acetyl‐D‐glucosamine strongly interfere with fungal and insect chitin synthases. Plant lectins with similar properties may be involved in plant‐pathogen interaction inter alia by suppressing fungal invasion. © 1993 Wiley‐Liss, Inc.
Semiochemically mediated foraging behavior in beneficial parasitic insects
Authors: Tumlinson James H. , Turlings Ted C. J. , Lewis W. Joe 
Published: February 2005

AbstractChemical cues enable female parasitic wasps to locate the eggs, larvae, or other life stages of the insects in or on which they place their eggs. These chemical signals, or semiochemicals, may be produced by the hosts and/or by the plants on which the hosts feed. The composition of the chemical signal often differs with different species of hosts or with different plants. New evidence suggests that the wasps exploit semiochemicals emitted by plants in response to insect herbivore feeding. The wasps learn to respond to the different blends of chemicals that indicate the location of their hosts and they can be trained to respond to a specific odor blend. Thus, it may be possible to increase their effectiveness for biological control by conditioning them, prior to their release, to search for a target pest in a particular crop. © 1993 Wiley‐Liss, Inc.
In vitro translation of diapause mRNA from the fat body of active and diapause larvae of the pink bollworm, Pectinophora gossypiella (Saunders)
Authors: Salama Mohamed S. , Miller Thomas A. 
Published: February 2005

AbstractA diapause associated protein (DAP) (Mr 103,000) was isolated from the hemolymph and fat body of diapausing fourth instar larvae of the pink bollworm Pectinophora gossypiella. The protein has been named Pectinophora diapause protein (PDP). The in vitro translation peptide patterns of total RNA from the fat body of actively feeding fourth instar, wandering, prediapause, early diapause, mid‐diapause, and late diapause larvae in rabbit reticulocyte lysates showed the presence of poly (A)+ RNA sequence of PDP. The antigen was immuno‐precipitated by polyclonal antiserum. It was concluded that the transcription of the PDP gene in the fat body cells started in the late fourth instar larva and that the expression of this gene was regulated at the level of transcription in the fat body of diapausing larvae. Northern hybridization analysis revealed that wandering fourth instar larvae (diapause individuals) maintain a relatively low level of diapause message (mRNA/2.4 kb) in their fat body cells which may be necessary for the induction of diapause. © 1993 Wiley‐Liss, Inc.
Interspecific variation in tephritid fruit fly larvae surface hydrocarbons
Authors: Sutton Bruce D. , Carlson David A. 
Published: February 2005

AbstractHydrocarbons extracted from seven species of tephritid fruit fly larvae were analyzed using capillary column gas‐liquid chromatography and gas‐liquid chromatography/mass spectrometry. Interspecific variation in hydrocarbon patterns was evaluated using both classical and nonparametric discriminant analysis for four of the seven Anastrepha taxa; A. acris, A. Fraterculus, A. suspensa and A. obliqua. Three of the four taxa, excluding A. acris, were correctly classified using a linear discriminant model at 72–83% and a nonparametric kernel density discriminant model at 87–92%. © 1993 Wiley‐Liss. Inc.
Proteolytic processing of the vitellogenin precursor in the boll weevil, Anthonomus grandis
Authors: Heilmann Larry J. , Trewitt Patrick M. , Kumaran A. Krishna 
Published: February 2005

AbstractThe soluble proteins of the eggs of the coleopteran insect Anthonomus grandis Boheman, the cotton boll weevil, consist almost entirely of two vitellin types with Mrs of 160,000 and 47,000. We sequenced their N‐terminal ends and one internal cyanogen bromide fragment of the large vitellin and compared these sequences with the deduced amino acid sequence from the vitellogenin gene. The results suggest that both the boll weevil vitellin proteins are products of the proteolytic cleavage of a single precursor protein. The smaller 47,000 M vitellin protein is derived from the N‐terminal portion of the precursor adjacent to an 18 amino acid signal peptide. The cleavage site between the large and small vitellins at amino acid 362 is adjacent to a pentapeptide sequence containing two pairs of arginine residues. Comparison of the boll weevil sequences with limited known sequences from the single 180,000 Mr honey bee protein show that the honey bee vitellin N‐terminal exhibits sequence homology to the N‐terminal of the 47,000 Mr boll weevil vitellin. Treatment of the vitellins with an N‐glycosidase results in a decrease in molecular weight of both proteins, from 47,000 to 39,000 and from 160,000 to 145,000, indicating that about 10–15% of the molecular weight of each vitellin consists of N‐linked carbohydrate. The molecular weight of the deglycosylated large vitellin is smaller than that predicted from the gene sequence, indicating possible further proteolytic processing at the C‐terminal of that protein. © 1993 Wiley‐Liss, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America.
Effects of intestinal insulin‐like peptide on glucose catabolism in mealworm larval fat body in vitro: Dependence on extracellular Ca2+ for its stimulatory action
Authors: Mtioui Abdelhamid , Gourdoux Lucienne , Fournier Bernard , Moreau Robert 
Published: February 2005

AbstractIn vitro hormonally induced variations of glucose catabolism in mealworm fat body tissue were examined by a microradiorespirometric method. An insulin‐like peptide (ILP) extracted from the midgut of last larval instar mealworm larvae significantly modified glucose catabolism and was dependent on energy metabolism and on the Ca2+ concentration in the culture medium. Using two different labelled substrate molecules, the stimulatory effects of ILP (compared with those of mammalian insulin) on the relative use of the pentose cycle as opposed to the glycolytic‐citric acid cycle by the mealworm fat body were measured in vitro. Metabolic variations were evaluated using either [1‐14C]glucose or [6‐14C]glucose as substrates. Time course and dose‐response curves of ILP and the hormonally induced variations in total CO2 and 14CO2 kinetics were determined. Modification in the specific radioactivity kinetics of 14CO2 derived from [1‐14C] glucose and [6‐14C] glucose molecules under hormonal effects were observed. As demonstrated in in vivo studies, ILP stimulated the relative utilization of the pentose cycle. However, this effect was observed much more rapidly, but for a shorter time, with fat body in vitro. Mammalian insulin produced similar, but not identical effects. Variations in transmembranous Ca2+ cellular exchanges, induced by either EGTA, nifedipine, or calcium ionophore ionomycin included in the culture medium, indicated that the stimulatory effects of ILP depends on this cation. © 1993 Wiley‐Liss, Inc.
Inhibition of cuticular lipid synthesis and its effect on insect survival
Authors: Juárez Patricia 
Published: February 2005

AbstractA new approach to insect control—using sodium trichloroacetate (NaTCA) to inhibit synthesis of the hydrophobic cuticular lipids that protect insects from dehydration—was tested on Triatoma infestans. In vivo and in vitro studies of incorporation of radioactive precursors showed diminished cuticular hydrocarbon synthesis after NaTCA treatment. Thin layer chromatography and scanning electron microscopy showed disruption of the cuticular lipid layer of NaTCA‐treated insects, which also have increased mortality and altered molting cycles. NaTCA treatment enhanced the penetration and increased the lethality of a contact insecticide. © 1994 Wiley‐Liss, Inc.
Characterization of a 24 kD parasitism‐specific hemolymph protein from pharate pupae of the caribbean fruit fly, Anastrepha suspensa
Authors: Rolle Rosa S. , Lawrence Pauline O. 
Published: February 2005

AbstractA parasitism‐specific protein was originally identified in the hemolymph of the Caribbean fruit fly Anastrepha suspensa parasitized by the braconid wasp Diachasmimorpha (Biosteres) longicaudata using single‐dimensional (1‐D) sodium dodecyl sulfate (SDS) PAGE. We now show that the protein is comprised of two closely migrating species both of which are glycoproteins of ≈︁ 24,000 Daltons (24 kD). The proteins were poorly resolved from whole hemolymph by 1‐D SDS PAGE, but were well resolved by two‐dimensional (2‐D) PAGE and isoelectric focusing. They have pl's of ≈︁ 6.3 and 6.7 and contain Man residues, based on their affinity for concanavalin A (Con A). The presence of GlcNAc, NeuAc, and GalNAc residues in both proteins was implicated by their binding to wheat germ agglutinin (WGA). The proteins bound WGA more intensely following mannosidase treatment which eliminated their affinity to Con A and further implicated the presence of internal GlcNAc residues. However, binding of the proteins to WGA in the presence of competing GlcNAc (1 M) was reduced but not eliminated and suggested that in addition to GlcNAc, other WGA‐binding sugar moieties, possibly NeuAc, a Sia, were present. To evaluate the presence of NeuAc, we treated the hemolymph with Vibrio cholerae neuraminidase which specifically cleaves terminal Sia. Samples of the neuraminidase‐digested proteins were evaluated by WGA binding and Western blotting with the use of an anti‐24 kD rabbit polyclonal serum to determine whether desialation eliminated the proteins' affinity to WGA or their immunoreactivity. Our results show that partial digestion of the 24 kD proteins with Vibrio cholerae neuraminidase resulted in two immunoreactive bands in Western blots of 1‐D gels but only one of these, the upper undigested 24 kD band, bound WGA. This confirmed the presence of Sia residues in the proteins and demonstrated that desialation increased their relative electrophoretic mobilities. © 1994 Wiley‐Liss, Inc.