Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Insect Control”

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 289 records · Page 16Linked to original sources
PubMed1978

Isolation of genotypic variants of Autographa californica nuclear polyhedrosis virus.

A nuclear polyhedrosis virus (MNPV) isolated from a lepidopteran (Noctuidae) insect, Autographa californica, was cloned by successive plaque purification using virions containing only one nucleocapsid per envelope as inoculum. The ability to clone the virus by this method was demonstrated by the isolation of nondefective, genotypic variants of the virus with similar but not identical restriction endonuclease fragment patterns. Five distinct variants were identified by genotypic analysis with HindIII, EcoRI, SalI, and Bam HI restriction endonucleases. The characteristic genotype of each variant was maintained upon passage in insect larvae. The isolation of these virus variants demonstrates (i) the heterogeneity of the uncloned virus preparation and (ii) the ability to clone MNPVs by plaque purification of media-derived nonoccluded virions. The A. californica MNPV is being considered for commercial use as a pesticide in the United States, and the cloning of the virus, in view of the heterogeneity detected, may be advisable. The cloning and genotype analyses are also significant with regard to understanding the genetic nature of multiply embedded NPVs (those NPVs containing more than one nucleocapsid per envelope in the occluded form of the virus) and indicate that further genetic analysis of these viruses is possible.

Animals↗
PubMed1986

Transition state analogs as ligands for affinity purification of juvenile hormone esterase.

Insect juvenile hormones are metabolized in numerous species of caterpillars by low abundance, highly specific esterases. Because of their role in regulating and possibly disrupting juvenile hormone titer and thus insect metamorphosis, they are of interest to developmental biologists as well as scientists interested in selective insect control. However, the enzymes have defied attempts to purify and characterize them. Juvenile hormone esterase activity can be inhibited by a variety of 3-substituted 1,1,1-trifluoropropanone sulfides. These apparent transition state analogs were used as ligands and eluting agents to purify juvenile hormone esterase from four insect species from 500-fold to over 1000-fold in high yield. After elution from the affinity column, the enzymes were radiolabeled with paraoxon and analyzed by electrophoresis, and the results demonstrate a high degree of purity. Transition state analogs may be useful for the affinity purification of other enzymes.

Acetone↗
PubMed1971

Aspects of research on insect growth hormones.

Current research on insect growth hormones includes studies on the binding of hormones to receptor molecules, probably proteins. Evidence has been obtained that this process does in fact occur and may be the means whereby the hormones "recognize" target tissues. Other studies on the possibility of a feedback effect when growth hormones are used for insect control suggest that there is a positive feedback relationship between the hormone titre and the activity of prothoracic glands and corpora allata, but the details are not yet clear. Cyclic adenosine 3',5'-monophosphate has an important role as "second messenger" in vertebrate endocrinology and may also be important in insects. Studies have shown that adenyl cyclase is present in pupal epidermis and the preliminary results have shown that it can be stimulated by a steroid hormone.

Adenylyl Cyclases↗
PubMedDate not supplied

Molecular characteristics of insect vitellogenins and vitellogenin receptors.

The recent cloning and sequencing of several insect vitellogenins (Vg), the major yolk protein precursor of most oviparous animals, and the mosquito Vg receptor (VgR) has brought the study of insect vitellogenesis to a new plane. Insect Vgs are homologous to nematode and vertebrate Vgs. All but one of the insect Vgs for which we know the primary structure are cleaved into two subunits at a site [(R/K)X(R/K)R or RXXR with an adjacent beta-turn] recognized by subtilisin-like proprotein convertases. In four of the Vgs, the cleavage site is near the N-terminus, but in one insect species, it is near the C-terminus of the Vg precursor. Multiple alignments of these Vg sequences indicate that the variation in cleavage location has not arisen through exon shuffling, but through local modifications of the amino acid sequences. A wasp Vg precursor is not cleaved, apparently because the sequence at the presumed ancestral cleavage site has been mutated from RXRR to LYRR and is no longer recognized by convertases. Some insect Vgs contain polyserine domains which are reminiscent of, but not homologous to, the phosvitin domain in vertebrate Vgs. The sequence of the mosquito VgR revealed that it is a member of the low-density lipoprotein receptor (LDLR) family. Though resembling chicken and frog VgRs, which are also members of the LDLR family, it is twice as big, carrying two clusters of cysteine-rich complement-type (Class A) repeats (implicated in ligand-binding) instead of one like vertebrate VgRs and LDLRs. It is very similar in sequence and domain arrangement to the Drosophila yolk protein receptor (YPR), despite a non-vitellogenin ligand for the latter. Though vertebrate VgRs, insect VgR/YPRs, and LDLR-related proteins/megalins all accommodate one cluster of eight Class A repeats, fingerprint analysis of the repeats in these clusters indicate they are not directly homologous with one another, but have undergone differing histories of duplications, deletions, and exon shuffling so that their apparent similarity is superficial. The so-called epidermal growth factor precursor region contains two types of motifs (cysteine-rich Class B repeats and YWXD repeats) which occur independently of one another in diverse proteins, and are often involved in protein-protein interactions, suggesting that they potentially are involved in dimerization of VgRs and other LDLR-family proteins. Like the LDLR, but unlike vertebrate VgRs and the Drosophila YPR, the mosquito VgR contains a putative O-linked sugar region on the extra-cellular side of the transmembrane domain. Its function is unclear, but may protect the receptor from membrane-bound proteases. The cytoplasmic tail of insect VgR/YPRs contains a di-leucine (or leucine-isoleucine) internalization signal, unlike the tight-turn tyrosine motif of other LDLR-family proteins. The importance of understanding the details of yolk protein uptake by oocytes lies in its potential for exploitation in novel insect control strategies, and the molecular characterization of the proteins involved has made the development of such strategies a realistic possibility.

Amino Acid Sequence↗
PubMed1978

Quantification of two viruses in technical preparations of Orgyia pseudotsugata baculovirus by means of buoyant density centrifugation of viral deoxyribonucleic acid.

A reliable method was developed for the quantitative determination of two nuclear polyhcdrosis viruses present in commercially prepared viral insecticides used against Orgyia pseudotsugata. Deoxyribonucleic acids, from nuclear polyhedrosis bundle virus and nuclear polyhedrosis single-rod virus, were separated on CsCl gradients according to their respective buoyant densities, 1.715 and 1.704 g/ml. The proportions of the two viruses were quantified by measuring the relative absorbance at 254 nm of their deoxyribonucleic acid peaks.

Animals↗
PubMed1978

Characterization of an alkaline protease associated with a granulosis virus of Plodia interpunctella.

An alkaline protease was found to be associated with the granulosis virus of the Indian meal moth. Plodia interpunctella. The protease was located within the protein matrix of the occluded virus and hydrolyzed the major constituent of this matrix, a 28,000-dalton protein (granulin), to a mixture of polypeptides ranging in molecular weight from 10,000 to 27,000. A rapid, sensitive assay for the protease was developed using radioactively labeled granulosis virus as substrate. With this assay, the proteolytic activity could be detected by measuring the release of acid-soluble peptides from the labeled virus. The protease had a pH optimum of 10.5 and a temperature optimum of 40 degrees C and was inhibited by diisopropyl phosphorofluoridate, phenylmethylsulfonyl fluoride, and L-(1-tosylamido-2-phenyl) ethyl chloromethyl ketone. Purification of the protease from matrix protein was achieved by anion-exchange and gel permeation chromatography. The molecular weight of the isolated protease, determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration, was approximately 14,000.

Animals↗
PubMed1996

Biotechnology and new integrated pest management approaches.

Area-wide pest management technologies will take on new appearances as the drive to eliminate and/or greatly reduce the use of chemical pesticides increases. The use of genetically altered insects has the most potential for successfully displacing certain pesticides, although the development of genetic engineering technologies for agricultural pest species is still in its infancy. Transformation vectors need to be developed as do transformation methodologies. Here we report the possibility of developing an interspecies vector and discuss ways in which such a vector could be used successfully in an integrated pest management system. If such an approach were developed, it could be utilized with other alternative methods, thereby providing a safe, ecologically sound means of controlling insect pests without damaging the agricultural economy.

Agriculture↗
PubMed1994

Expression cloning of an insect diuretic hormone receptor. A member of the calcitonin/secretin receptor family.

Insect diuretic hormones and their receptors regulate fluid and ion secretion and thus are attractive targets for the design of novel insect control agents. A complementary DNA clone encoding a corticotropin-releasing factor-related diuretic hormone receptor from the tobacco hornworm Manduca sexta was isolated by expression cloning in COS-7 cells. The receptor consists of 395 amino acids and contains seven putative transmembrane domains. The expressed receptor binds M. sexta diuretic hormone, as well as several related insect diuretic peptides with high affinity. Furthermore, each of these peptides stimulate adenylate cyclase in COS-7 cells transfected with the receptor. The M. sexta diuretic hormone receptor is homologous to the receptors for calcitonin, secretin, vasoactive intestinal peptide, parathyroid hormone, glucagon-like peptide 1, growth hormone-releasing hormone, pituitary adenylate cyclase-activating polypeptide, and glucagon. The M. sexta diuretic hormone receptor is the first nonmammalian member of this family to be identified.

Amino Acid Sequence↗
PubMed1991

Toxicity evaluation of Bayluscide and malathion to three developmental stages of freshwater snails.

Laboratory studies were conducted to assess the conditions under which the use of malathion in ricelands of Cameroon may impact the transmission of schistosomiasis. Helisoma trivolvis and Biomphalaria havanensis were selected as test organisms due to the lack of intermediate snail hosts in the U.S. Using Bayluscide as a reference molluscicidal compound, malathion was tested against snail eggs, juveniles, and adults. Snail eggs were more susceptible to Bayluscide and malathion than juvenile snails which in turn were more susceptible than adult snails. A Bayluscide concentration of 0.200 mg/L caused 100% mortality to adults of both snail species after 24 h exposure. This relatively high toxicity of Bayluscide to freshwater snails is one of the reasons why it has been recommended by the World Health Organization as the molluscicide of choice for control of schistosome-bearing snails. The concentrations of malathion resulting in 100% kill of adult snails after 24 h exposure were 1,200 mg/L for H. trivolvis and 500 mg/L for B. havanensis. After 48 h exposure, these concentrations were reduced to 500 mg/L and 300 mg/L, respectively. Therefore it is expected that the use of malathion for insect control in ricelands of Cameroon may affect the survival of freshwater snails including the intermediate hosts of bilharziasis.

Animals↗
PubMed1977

The DNA contained by nuclear polyhedrosis viruses isolated from four Spodoptera spp. (Lepidoptera, Noctuidae); genome size and configuration assessed by electron microscopy.

The mol. wt. of the DNA from four nuclear polyhedrosis viruses isolated from Spodoptera littoralis, S. exempta, S. exigua and S. frugiperda were determined to be 84, 80, 68 and 74 X 10(6), respectively, by electron microscopy. The molecules were demonstrated to exist as double-stranded relaxed circular or supercoiled DNA, though linear forms of DNA were also observed.

Animals↗
PubMed1993

The reconstruction and expression of a Bacillus thuringiensis cryIIIA gene in protoplasts and potato plants.

A Bacillus thuringiensis (B.t.) cryIIIA delta-endotoxin gene was designed for optimal expression in plants. The modified cry gene has the codon usage pattern of an average dicot gene and does not contain AT-rich nucleotide sequences typical of native B.t. cry genes. We assembled the 1.8 kb cryIIIA gene in nine blocks of three oligonucleotide pairs. For two DNA blocks, the polymerase chain reaction was used to enrich for correctly ligated pairs. We compared modified cryIIIA gene with native gene expression by electroporation of dicot (carrot) and monocot (corn) protoplasts. CryIIIA-specific RNA and protein was detected in carrot and corn protoplasts only after electroporation with the rebuilt gene. Transgenic potato lines were generated containing the redesigned cryIIIA gene under the transcriptional control of a chimeric CaMV 35S/mannopine synthetase (Mac) promoter. Out of 63 transgenic potato lines, 58 controlled first-instar Colorado potato beetle (CPB) larvae in bioassays. Egg masses which produced ca. 250,000 CPB larvae were placed on replicate clones of 56 transgenic potatoes. No CPB larvae developed past the second instar on any of these plants. Plants expressing high levels of delta-endotoxin were identified by their toxicity to more resistant third-instar larvae. We show there was good correlation between insect control and the levels of delta-endotoxin RNA and protein.

Amino Acid Sequence↗