Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Spodoptera”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources
PubMed2006

Sequential sampling protocols for Spodoptera frugiperda (Lepidoptera: Noctuidae), on Zea mays fields: influence of sampling unit size.

Spodoptera frugiperda (J.E. Smith) is a major pest in maize fields in Argentina. However, a sampling method that accounts for spatial pattern and allows reliable pest density estimations is still lacking. This paper addresses the issue of how sampling unit size can influence the characterization of S. frugiperda spatial pattern and the performance of sampling plans. An intensive sampling programme for S. frugiperda larvae was carried out in maize fields from October until March in four growing seasons. On each sampling date, 12 to 20 sampling units were taken at random. Each unit consisted of 1, 2, 4, 6, 8, 10 or 12 consecutive plants along a row. The linearized version of the Taylor's power law (TPL) was fitted to mean and variance estimated for each sampling date and data set through least squares regression. In general, b values from TPL were significantly >1 (P<0.05), indicating an aggregated sampling distribution. Regression slopes (b) ranged from 1.28 to 1.48 in small larvae and from 1.06 to 1.24 in large larvae, indicating stronger clumping in the former. TPL parameters were used to develop constant precision sampling plans. The efficiency of these plans in terms of expected total cost (searching and handling sampling units) was very sensitive to the size of the sampling units with small larvae but not with large larvae. The influence of sampling unit size and spatial pattern on TPL parameters and sampling costs is discussed.

Animals↗
PubMed1995

Agonist-dependent phosphorylation of human muscarinic receptors in Spodoptera frugiperda insect cell membranes by G protein-coupled receptor kinases.

Agonist-dependent phosphorylation of G protein-coupled receptors (GPRs) by G protein-coupled receptor kinases (GRKs) is proposed to be a key event initiating homologous receptor desensitization. A technical limitation hindering identification of GPRs as GRK substrates has been the necessity to use purified and reconstituted receptors in GRK assays. Here, the human m2 and human m3 (hm3) muscarinic cholinergic receptors (mAChRs), which couple to attenuation of adenylyl cyclase and stimulation of phospholipase C, respectively, were expressed in Spodoptera frugiperda insect cells and an in vitro approach to studying GPR phosphorylation by GRKs in crude membranes was developed. The m2 mAChR, a known substrate of certain GRKs, was used to validate the approach. The GRK isoform beta-adrenergic receptor kinase (beta ARK)1 phosphorylated the membrane-bound human m2 mAChRs in an agonist-dependent manner. The results demonstrated that endogenous membrane-bound beta gamma subunits of G proteins stimulated the phosphorylation of the membrane-bound m2 mAChR. To reveal new GRK substrates, we tested the expressed hm3 mAChRs. The membrane-bound hm3 mAChRs were phosphorylated by beta ARK1 in an agonist-dependent, G beta gamma-enhanced manner. This is the first demonstration that hm3 mAChRs can serve as substrates for GRKs. The stoichiometry of receptor phosphorylation was approximately 2 mol of phosphate/mol of receptors in the absence of G beta gamma and approximately 4 mol of phosphate/mol of receptors upon addition of G beta gamma. When the specificity of various GRKs towards mAChRs was assessed, beta ARK2 phosphorylated the agonist-activated hm3 mAChRs as efficiently as did beta ARK1; however, neither GRK5 nor GRK6 significantly phosphorylated the hm3 mAChRs under similar conditions. The approach of studying GRK-mediated phosphorylation of GPRs in their membrane-bound state identified the hm3 mAChRs as new substrates for GRKs. This approach should be valuable in identifying other new substrates of GRKs and should aid in studies that elucidate GRK/GPR pairing.

Animals↗
PubMed1996

Differential coupling of rat D2 dopamine receptor isoforms expressed in Spodoptera frugiperda insect cells.

By using a baculovirus expression system, the two isoforms of the rat D2 dopamine receptor were expressed at densities ranging up to 15 pmol/mg of protein. D2L and D2S dopamine receptors expressed in aline of Spodoptera frugiperda (Sf9) insect cells Sf9cells, displayed high affinity for the antagonists spiroperidol and (+)-butaclamol and the agonist N-propylnorapomorphine. Antisera raised against the D2 receptor immunoprecipitated binding sites for a radiolabeled D2 antagonist from solubilized extracts of infected Sf9cells. In immunoblots of Sf9cells infected with recombinant D2 baculovirus, these antisera recognized a major species of protein of approximately 46 kDa. Photoaffinity-labeling of infected Sf9cells using N-(p-azido-m-[125I]iodophenethyl)spiperone also identified a protein of this size, suggesting that D2 receptors expressed in Sf9cells are largely unglycosylated. In cells expressing receptors at a density greater than 1 pmol/mg, GTP-sensitive, high-affinity binding of agonists was not detected in studies of the inhibition of the binding of a radiolabeled D2 antagonist. When expression levels were under 1 pmol/mg, the binding of agonists was sensitive to the addition of guanine nucleotides, indicating that D2 receptors were coupled to endogenous G proteins. Endogenous G proteins enable both isoforms of D2 receptors to couple to the inhibition of adenylyl cyclase activity. The high-affinity state of the D2 receptor was directly measured using a radiolabeled agonist. Although the density of receptors increased with longer times after infection, the density of high-affinity sites reached a maximum of approximately 40 fmol/mg 30 to 36 hr after infection. Coexpression of D2 receptors and G protein subunits in Sf9cells dramatically increased the density of high-affinity sites, whereas the total density of receptors was unchanged, confirming that D2 receptors in Sf9 cells can exist in the high-affinity-coupled state, but that appropriate G proteins are expressed at relatively low levels. The density of D2S receptors converted to a coupled, agonist-preferring state when coexpressed with G proteins subunits (alpha i1, beta 1 and gamma 2) was 5 times greater than that of D2L receptors expressed under the same conditions, consistent with the hypothesis that D2 dopamine receptor isoforms differentially couple to alpha i1.

Animals↗
PubMed1995

In vivo and in vitro characterization of several isolates of spodoptera exigua nuclear polyhedrosis virus.

Spodoptera exigua nuclear polyhedrosis viruses (SeNPVs), isolated form five geographically distinct regions of Japan and Thailand, were characterized by their DNA restriction endonuclease pattern, level of virus production in a continuous cell line of S. exigua and biological activity to S. exigua larvae. The EcoRI and PstI fragments exhibited similar overall patterns with minor differences. Digestion of virus DNA from a plaque-purified isolate, SeNPV-I1, with PstI yielded 14 fragments and the estimated genome size was approximately 123 kbp. The SeNPV wild isolate from Kagoshima, SeNPV-KW, showed the highest yield of extracellular virus (ECV) in the Se301 cell line of S. exigua among five wild isolates, but there was no significant difference in the level of polyhedral inclusion body (PIB) formation. In comparative studies of biological activity using 2nd-instar S. exigua larvae, SeNPV-KW had the highest virulence with an LD50 value of 3.0 PIBs per larva. When 16 clones, plaque-purified from the Isahaya isolate, SeNPV-IW, were examined for genetic relatedness, seven distinct EcoRI patterns were observed, indicating that SeNPV-IW wild isolate consisted of a mixture of different genotypes.

Animals↗
PubMed1996

Direct inhibition of (Z)-9 desaturation of (E)-11-tetradecenoic acid by methylenehexadecenoic acids in the biosynthesis of Spodoptera littoralis sex pheromone.

Analysis by gas chromatography coupled to mass spectrometry demonstrated that 11,12-methylenehexadec-11-enoic acid and 12,13-methylenehexadec-12-enoic acid are beta-oxidized in Spodoptera littoralis sex pheromone gland to 9, 10-methylenetetradec-10-enoic acid and 10,11-methylenetetradec-10-enoic acid, respectively. This result supported our previous hypothesis that inhibition of the (Z)-9 desaturation of (E)-11-tetradecenoic acid by those C-16 fatty acids is actually caused by their corresponding beta-oxidation products. However, although (2,2,3,3-2H4)-11,12-methylenehexadec-11-enoic acid was not chain-shortened to the C-14 derivative, its activity as inhibitor of the (Z)-9 desaturation reaction was similar to that exhibited by 11,12-methylenehexadec-11-enoic acid. Therefore, the C-16 cyclopropene fatty acids may inhibit the (Z)-9 desaturation enzyme by themselves, probably through interaction of the cyclopropene ring with a binding site of the enzyme with the substrate double bond.

Animals↗
PubMed1997

Baculovirus-directed expression of rabbit UDP-glucuronosyltransferases in Spodoptera frugiperda cells.

The rabbit liver UDP-glucuronosyltransferase (UGT) cDNAs that encode the 4-hydroxybiphenyl UGT2B13 and 4-nitrophenol UGT1A6 have been cloned into baculovirus. Spodoptera frugiperda (SF-9) cells infected with the UGT recombinant baculovirus produced significant amounts of protein, which was detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblot analysis, and pulse chase with 35S-amino acids. The expression of the UGT proteins in SF-9 cells were detected at approximately 24 hr postinfection, with maximal levels of protein seen at 48 hr. Immunoprecipitation of newly synthesized 35S-labeled proteins demonstrated that the maximal rate of protein synthesis in SF-9 cells infected with the UGT baculovirus occur at 48 hr postinfection, although the proteins are abundant in the cells for up to 96 hr. When compared with the expression levels of the same cDNAs through transient transfection into COS-1 cells, the insect-derived UGT proteins showed nearly 50- to 100-fold greater protein accumulation. Although kinetic analysis demonstrated that turnover rate of the SF-9-expressed proteins were greater than their counterparts in COS-1 cells, K(M) values for UGT1A6 and UGT2B13 in SF-9 and COS-1 cells were similar. Overall, SF-9 cells seem to serve as an efficient expression system for the production of the mammalian UGTs.

Animals↗
PubMed1997

Multiplication of Spodoptera littoralis granulosis virus in a cell line established from Phthorimaea operculella.

A complete replication of the Spodoptera littoralis granulosis virus (SpliGV) was obtained, in vitro by both virus infection and DNA transfection in the ORS-Pop-95 (Pop-95) cell line established from embryonic cells of the potato tuber moth, Phthorimaea operculella. SpliGV multiplied significantly during several passages in Pop-95 cells at 19 degrees C. When the cells were infected and kept at 19 degrees C for the first 4 hrs and then at 27 degrees C for the rest of the experiment (20 days), the viral multiplication proceeded at the same rate. Comparison of SpliGV progenies, multiplied either in vivo or in vitro, using electron microscopy and restriction profile analysis, showed their identity.

Animals↗
PubMed1999

Feeding preferences of spodoptera exigua in response to form and concentration of selenium

Minimal information is available on the impact of various organic and inorganic forms of the ecologically and agriculturally important pollutant, selenium (Se), on insect herbivores. We conducted bioassays with artificial diet to examine the feeding responses of a generalist herbivore, Spodoptera exigua (Hubner) (Lepidoptera: Noctuidae), to various forms and concentrations of Se. Two different-aged cohorts of larvae were examined in choice tests with control diets vs. test diets incorporating lethal concentrations (LC(10), LC(30), LC(50), and LC(70)) of sodium selenate, sodium selenite, seleno-DL-cystine, and seleno-DL-methionine. Tests initiated with neonates showed larvae significantly preferred control diet over diet with sodium selenate, sodium selenite, or selenocystine, but at most concentrations showed no preference between selenomethionine and control diet. Choice tests initiated with third instars demonstrated a preference for control diet over sodium selenate treatments, and sodium selenite treatments. In contrast, no significant responses were found in tests initiated with third instars offered the choice between selenocystine or selenomethionine and untreated controls. Additionally, comparisons of consumption demonstrated that inorganic selenium compounds were antifeedants whereas the organic selenium compounds tested have little antifeedant activity. The toxicity of all of the tested forms of selenium, in combination with the lack of antifeedant activity of some compounds, has the potential to affect both the distribution and diversity of terrestrial herbivores in both agricultural and natural systems. Arch. Copyright 1999 Wiley-Liss, Inc.

Journal Article↗
PubMed1992

Site-directed mutagenesis of human protein disulphide isomerase: effect on the assembly, activity and endoplasmic reticulum retention of human prolyl 4-hydroxylase in Spodoptera frugiperda insect cells.

Protein disulphide isomerase (PDI) is a highly unusual multifunctional polypeptide, identical to the beta-subunit of prolyl 4-hydroxylase. It has two -Cys-Gly-His-Cys- sequences which represent two independently acting catalytic sites of PDI activity. We report here on the expression in baculovirus vectors of various mutant PDI/beta-subunits together with a wild-type alpha-subunit of the human prolyl 4-hydroxylase alpha 2 beta 2 tetramer in Spodoptera frugiperda insect cells. When either one or both of the -Cys-Gly-His-Cys- sequences was converted to -Ser-Gly-His-Cys-, a tetramer was formed as with wild-type PDI/beta-subunit. This tetramer was fully active prolyl 4-hydroxylase. The data demonstrate that PDI activity of the PDI/beta-subunit is not required for tetramer assembly or for the prolyl 4-hydroxylase activity of the tetramer, and thus other sequences of the PDI/beta-subunit may be critical for keeping the alpha-subunits in a catalytically active, non-aggregated conformation. Measurements of the PDI activities of tetramers containing the various mutant PDI/beta-subunits demonstrated that the activity of the wild-type tetramer is almost exclusively due to the C-terminal PDI catalytic sites, which explains the finding that the PDI activity of the PDI/beta-subunit present in the tetramer is about half that in the free polypeptide.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Functional expression of rat peroxisomal acyl-CoA oxidase in Spodoptera frugiperda cells.

A cDNA coding the 661-residue rat peroxisomal fatty acyl-CoA oxidase (ACOX) has been constructed and expressed as catalytically active protein in Spodoptera frugiperda (Sf9) insect cells using baculovirus expression system. Recombinant viral clones were purified and the expressed protein was identified by immunoblotting and catalytic activity. In the rat liver, ACOX consists of three polypeptide components A, B and C, with relative molecular mass of 72 kDa, 51 kDa and 21 kDa, respectively. In Sf9 insect cells infected with the recombinant virus, ACOX protein (component A) was expressed up to 15% of the total cellular protein. Immunoblot analysis demonstrated that besides component A, components B and C were also present in Sf9 cells, suggesting that these components are derived from component A by post-translational proteolytic cleavage. However, unlike in rat liver, baculovirus generated ACOX in insect cells had reduced amounts of components B and C with an estimated molar ratio of A, B, C of 5:1:1 in Sf9 cells vs 1:5:5 in rat liver. By immunofluorescence and immunocytochemical methods the overexpressed recombinant ACOX was identified both in the cytoplasm and the nucleus of Sf9 cells. Polyclonal antibodies raised against recombinant ACOX recognized rat liver ACOX on immunoblotting. Baculovirus Sf9 system provides high-efficiency expression of functional ACOX and can be used to express specific mutant and truncated ACOX cDNAs for further characterization.

Acyl-CoA Oxidase↗
PubMed1993

Effect of Beauveria bassiana and Candida albicans on the cellular defense response of Spodoptera exigua.

A marked difference in the cellular response of Spodoptera exigua was observed when larvae were challenged with the insect mycopathogen Beauveria bassiana versus the yeast Candida albicans. Both fungi were rapidly phagocytized by circulating hemocytes. The relative growth rate of C. albicans as measured by daughter cell formation was partially suppressed, whereas B. bassiana blastospores produced germ tubes at rates equivalent to those under in vitro conditions. Limited growth by C. albicans within the phagocytic cells stimulated nodulation by hemocytes resulting in the protection of challenged larvae to C. albicans. Alternatively, B. bassiana suppressed the spreading ability of S. exigua hemocytes. These suppressed larvae, while capable of phagocytizing C. albicans, were unable to produce multicellular nodules. Circulating vegetative cells of both C. albicans and B. bassiana were observed to proliferate within these immunosuppressed host larvae.

Animals↗
PubMed1997

Microbial Contamination in Spodoptera littoralis Nuclear Polyhedrosis Virus Produced in Insects in Egypt

Spodoptera littoralis nuclear polyhedrosis virus produced in Egypt, for use in field trials for the control of S. littoralis on cotton, was subject to microbiological examination to quantify microbial contamination. Bacteria were found to be present at 10(6)-10(9) colony-forming units/ml in virus suspensions containing 2.1 x 10(9) polyhedral inclusion bodies/ml. Batches were found to contain between 2 and 11 different species of contaminant microbes. No primary human pathogens of medical importance were found. The dominant species were fecal Streptococci and two Bacillus species, B. cereus and B. sphaericus. The Streptococci were derived from the normal gut flora found in healthy insects; the Bacillus species were common opportunistic saprophytes which gained access to the product by colonizing dead larvae and diet waste. Purification methods based on centrifugation were found to be ineffective in removing bacteria and improved methods of hygiene and harvesting appeared to be of more value in reducing contamination.

Journal Article↗
PubMed1994

Crystallization and initial X-ray crystallographic characterization of recombinant bovine inositol polyphosphate 1-phosphatase produced in Spodoptera frugiperda cells.

Bovine inositol polyphosphate 1-phosphatase, a monomeric protein with a molecular mass of 44,000 Da, hydrolyzes the 1-position phosphate from inositol 1,3,4-trisphosphate and inositol 1,4-bisphosphate. The low abundance of inositol polyphosphate 1-phosphatase in tissues has precluded structural studies requiring large quantities of enzyme. We used recombinant Baculovirus harboring the cDNA of bovine inositol polyphosphate 1-phosphatase to infect Spodoptera frugiperda (Sf9) insect cells. Recombinant protein (25 mg per 1 x 10(9) cells) was purified to homogeneity. The enzyme produced in Sf9 cells was similar to the native purified protein as determined by immunoblotting catalytic properties, and inhibition by lithium ions. Crystals of the purified recombinant enzyme were grown by vapor diffusion. Precession photography was used to determine the parameters of inositol polyphosphate 1-phosphatase crystals. The tetragonal crystals belong to the space group P4(1) or P4(3), have unit cell dimensions of a = b = 51.6 A, c = 143.3 A, alpha = beta = gamma = 90 degrees, and contain one molecule per asymmetric unit. We have collected a complete diffraction data set extending to 2.3 A and are currently attempting to solve the three-dimensional structure of bovine inositol polyphosphate 1-phosphatase using a multiple isomorphous replacement strategy.

Animals↗
PubMed1993

Immunological characterization of the VSV nucleocapsid (N) protein expressed by recombinant baculovirus in Spodoptera exigua larva: use in differential diagnosis between vaccinated and infected animals.

Vesicular stomatitis is a viral disease of cattle, pigs, and horses. The disease is characterized by vesicular lesions on the epithelium of the mouth, feet, and teats. The pathological lesions are virtually indistinguishable from that of foot-and-mouth disease. We have developed a recombinant baculovirus that expresses the nucleocapsid (N) protein of the New Jersey serotype of vesicular stomatitis virus (VSVNJ) in insect cells (Sf9) and larvae (Spodoptera exigua). The gene was expressed under control of the polyhedrin promoter as a fusion or nonfusion protein. The recombinant N protein expressed in insect cells could not be distinguished from N protein produced in VSVNJ-infected CHO cells by immunological and biochemical analyses. The level of expression of N as a percentage of the total protein in Sf9 cells was 41% for the fusion and 60% for the nonfusion protein. Higher level (68%) of expression of the nonfusion N protein was obtained in larvae. Recombinant N protein was used in an ELISA to distinguish animals vaccinated with a recombinant VSV glycoprotein from those exposed to the whole virus by infection or classical vaccine. Lysate of a single infected larva (0.2-0.3 g) was adequate for coating ELISA plates to perform 10,000 serum assays in duplicate.

Amino Acid Sequence↗
PubMed1993

Characterization of the replication of plasmids containing hr sequences in baculovirus-infected Spodoptera frugiperda cells.

The replication of a series of plasmids, each containing one or more of 6 homologous regions (hrs) from the Autographa californica multinucleocapsid nuclear polyhedrosis virus (AcMNPV) genome, was investigated in AcMNPV-infected Spodoptera frugiperda cells. Although a construct containing hr2 showed the most efficient replication, the sequences flanking the hr region appeared to influence the levels of replication. Plasmids with non-hr-containing AcMNPV inserts showed greatly reduced replication relative to hr-containing plasmids. A variety of features of hr-containing plasmid replication were characterized. These included the time course of plasmid replication and the influence of plasmid concentration and multiplicity of infection of the helper AcMNPV on replication efficiency. It was found that replicated plasmid DNA was detectable by 36 hr p.i. and plateaued by 60 hr p.i. Under our experimental conditions, plasmid levels of 0.5-2 micrograms/1.25 x 10(6) cells and multiplicities of infection of 0.1 to 10 produced optimal levels of plasmid replication. The transfection procedure was shown to delay viral DNA replication by about 12 hr. Experiments directed toward determining the form of the replicated hr-containing plasmid DNA were conducted using partial restriction enzyme digestion. The results indicated that the AcMNPV-replicated plasmids were composed of high molecular weight concatemers.

Animals↗
PubMed1978

Crystalloid structures within giant mitochondria of the prothoracic glands of Spodoptera littoralis (Bois) (Lepidoptera).

The fine structure of the prothoracic glands of Spodoptera littoralis was investigated during the first half of the last larval instar. The secretory cells have two types of mitochondria, micromitochondria and macromitochondria. The micromitochondria have rounded to elongated profiles and sometimes branch. They contain lamellar, tubular and also tubulo-vesicular cristae. The macromitochondria appear generally rounded or oval and possess tubular cristae. Many regular parallel membranes appear within macromitochondria. Favorable sections show tubular structures packed in honeycomb fashion. The mitochondrial cristae are in connection with the tubular structures. Honeycomb and parallel membranes increase in number as the size of the macromitochondria increases.

Animals↗
PubMed1981

The fine structure of the compound eye of the African armyworm moth, Spodoptera exempta Walk. (Lepidoptera, Noctuidae).

The morphology of the compound eye of the noctuid moth Spodoptera exempta was investigated by electron microscopy. This eucone superposition eye is composed of about 8000 ommatidia. Each ommatidium is surrounded by six secondary pigment cells showing pigment movement according to the state of adaptation. It contains four crystalline cone cells forming together a crystalline cone and tract, two primary pigment cells, which encompass the crystalline cone, and usually eight retinula cells. On the basis of their rhabdomeric structure, three types of retinula cells can be distinguished. According to the structure of the rhabdom, two types of ommatidia are found in different regions of the eye. The rhabdom of the lobed type, providing more than 80% of ommatidia, is composed of V-shaped rhabdomeres with fanwise arranged microvilli. The rhabdom of the square type, found in a small area in the dorsal region of the eye, consists of triangular rhabdomeres with parallel microvilli. The functional significance of this difference is discussed.

Animals↗
PubMed1991

Plasmodium falciparum: recombinant baculoviruses direct the expression of circumsporozoite proteins in Spodoptera frugiperda cell cultures.

The DNA coding for the circumsporozoite protein (CPS) of Plasmodium falciparum has been cloned into the baculovirus expression vector pAcYM1 and expressed in Spodoptera frugiperda (Sf9) insect cells. Three DNA constructs have been made: the first one directs the synthesis of the complete CSP (aa 1-412), the second leads to the production of a species devoid of the anchor domain (aa 1-391) and the third one to a molecule lacking both signal and membrane anchor sequences (aa 18-391). All three recombinant CPS were produced at about 3 micrograms per 10(6) infected cells and were characterized in terms of immunoreactivity and apparent molecular weight. Analytical purification of the recombinant proteins was achieved by a combination of heat treatment, acidification, isoelectric focusing and ion exchange chromatography. The purified material, when injected into mice, generated only modest antibody responses, although antisera from immunized mice reacted with control CSP antigens carrying or not the major immunodominant repeat region.

Animals↗