Ascorbic acid content is one of the nutritive parameters researchers are trying to enhance in pla... more Ascorbic acid content is one of the nutritive parameters researchers are trying to enhance in plants. This study investigated the effect of altering dietary ascorbic acid concentrations in the host larvae of a beneficial wasp, Euplectrus comstockii and a baculovirus AcMNPV. Life ...
Chitin is an extracellular biopolymer that contributes to the cuticular structural matrix in arth... more Chitin is an extracellular biopolymer that contributes to the cuticular structural matrix in arthropods. As a consequence of its rigid structure, the chitinous cuticle must be shed and replaced to accommodate growth. Two chitin synthase genes that encode for chitin synthase A (ChSA), which produces cuticular exoskeleton, and chitin synthase B (ChSB), which produces peritrophic membrane, were characterized in the genomes of two heliothine moths: the corn earworm/cotton bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) and the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). In both moths, the two genes were arranged in tandem with the same orientation on the same strand with ChSB located 5' of ChSA. Sequence comparisons showed that the coding sequences were highly conserved with homologues from other species but that the tandem juxtaposed genomic arrangement of the two genes was unique in these insects. The mechanism that has led to this arrangement is unclear but is most likely a recent recombinational event. Transcript mapping of HzChSB and HzChSA in H. zea demonstrated that both transcripts were differentially spliced in various tissues and larval stages. The identification of the HzChSB-E12b alternate spliced transcript is the first report of alternate splicing for the ChSB group. The importance of this splice form is not clear because the protein produced would lack any enzymatic activity but retain the membrane insertion motifs. As for other insects, these genes provide an important target for potential control through RNAi but also provide a subject for broad scale genomic recombinational events.
Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology, 1996
The hypolipidemic agent, 5-tetradecyloxy-2-furanocarboxylic acid (TOFA), blocks acetyl-CoA carbox... more The hypolipidemic agent, 5-tetradecyloxy-2-furanocarboxylic acid (TOFA), blocks acetyl-CoA carboxylase, the rate-limiting step in the synthesis of fatty acids. We examined the effect of dietary TOFA on larval growth and development of the southwestern corn borer, Diatraea grandiosella. Dietary levels of 200 and 300 ppm TOFA (wet wt) suppressed both growth and development. A reciprocal transfer experiment using the control and
We studied how biologically relevant trace metals (i.e., micronutrients) in the hemolymph of larv... more We studied how biologically relevant trace metals (i.e., micronutrients) in the hemolymph of larval Heliothis virescens and Helicoverpa zea (Lepidoptera: Noctuidae) changed in response to per os baculovirus infection, larval development, and injection of heat-killed bacteria. Concentrations of hemolymph Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, and Zn were measured using inductively coupled plasma-mass spectrometry. H. virescens larvae exhibited greater fluctuations in hemolymph trace metal levels in response to baculovirus infection and development than did H. zea larvae. H. zea single nucleopolyhedrosis virus infection significantly altered the levels of Cu, Fe, Mg, Mn, Mo, and Zn in fourth instar H. virescens larvae. Conversely, in fifth instar H. virescens and both H. zea instar infections, no metal levels were significantly different between infected and uninfected larvae. In fourth instar H. virescens hemolymph, Cu, Fe, Mo, and Zn increased during development. Cu, Fe, Mg, Mn, Mo, and Zn...
The genome of a granulovirus isolated from the Old World bollworm, Helicoverpa armigera, was comp... more The genome of a granulovirus isolated from the Old World bollworm, Helicoverpa armigera, was completely sequenced. The size of the Helicoverpa armigera granulovirus (HearGV) genome is 169,794 nt containing 179 open reading frames (ORFs), making it the second largest baculovirus genome analyzed to date. The genomes of HearGV and the Xestia c-nigrum GV (XecnGV) exhibit extensive sequence similarity and co-linearity, with both genomes containing the same nine homologous regions (hrs) with conserved structure and locations and sharing 167 open reading frames (ORFs). Phylogenetic inference and pairwise analysis of Kimura-2-parameter nucleotide distances for the lef-8, lef-9, and granulin genes indicate that HearGV is part of a cluster of granuloviruses typified by XecnGV. The HearGV genome contains all 62 ORFs found in common among other fully sequenced lepidopteran baculovirus genomes, as well as seven ORFs unique to HearGV. In addition, HearGV and XecnGV genomes share 20 ORFs not found among other baculovirus genomes sequenced to date. In addition to possessing ten ORFs with sequence similarity to baculovirus repeated ORFs (bro), the HearGV genome contains members of two other gene families with homologues in ascovirus, nucleopolyhedrovirus, and entomopoxvirus genomes. Alignment of the HearGV and XecnGV genome sequences revealed that HearGV is missing approximately 16.6 kbp of XecnGV-homologous sequence and contains approximately 8.2 kbp of sequence not found in the XecnGV genome.
Ascorbic acid content is one of the nutritive parameters researchers are trying to enhance in pla... more Ascorbic acid content is one of the nutritive parameters researchers are trying to enhance in plants. This study investigated the effect of altering dietary ascorbic acid concentrations in the host larvae of a beneficial wasp, Euplectrus comstockii and a baculovirus AcMNPV. Life ...
Chitin is an extracellular biopolymer that contributes to the cuticular structural matrix in arth... more Chitin is an extracellular biopolymer that contributes to the cuticular structural matrix in arthropods. As a consequence of its rigid structure, the chitinous cuticle must be shed and replaced to accommodate growth. Two chitin synthase genes that encode for chitin synthase A (ChSA), which produces cuticular exoskeleton, and chitin synthase B (ChSB), which produces peritrophic membrane, were characterized in the genomes of two heliothine moths: the corn earworm/cotton bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) and the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). In both moths, the two genes were arranged in tandem with the same orientation on the same strand with ChSB located 5' of ChSA. Sequence comparisons showed that the coding sequences were highly conserved with homologues from other species but that the tandem juxtaposed genomic arrangement of the two genes was unique in these insects. The mechanism that has led to this arrangement is unclear but is most likely a recent recombinational event. Transcript mapping of HzChSB and HzChSA in H. zea demonstrated that both transcripts were differentially spliced in various tissues and larval stages. The identification of the HzChSB-E12b alternate spliced transcript is the first report of alternate splicing for the ChSB group. The importance of this splice form is not clear because the protein produced would lack any enzymatic activity but retain the membrane insertion motifs. As for other insects, these genes provide an important target for potential control through RNAi but also provide a subject for broad scale genomic recombinational events.
Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology, 1996
The hypolipidemic agent, 5-tetradecyloxy-2-furanocarboxylic acid (TOFA), blocks acetyl-CoA carbox... more The hypolipidemic agent, 5-tetradecyloxy-2-furanocarboxylic acid (TOFA), blocks acetyl-CoA carboxylase, the rate-limiting step in the synthesis of fatty acids. We examined the effect of dietary TOFA on larval growth and development of the southwestern corn borer, Diatraea grandiosella. Dietary levels of 200 and 300 ppm TOFA (wet wt) suppressed both growth and development. A reciprocal transfer experiment using the control and
We studied how biologically relevant trace metals (i.e., micronutrients) in the hemolymph of larv... more We studied how biologically relevant trace metals (i.e., micronutrients) in the hemolymph of larval Heliothis virescens and Helicoverpa zea (Lepidoptera: Noctuidae) changed in response to per os baculovirus infection, larval development, and injection of heat-killed bacteria. Concentrations of hemolymph Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, and Zn were measured using inductively coupled plasma-mass spectrometry. H. virescens larvae exhibited greater fluctuations in hemolymph trace metal levels in response to baculovirus infection and development than did H. zea larvae. H. zea single nucleopolyhedrosis virus infection significantly altered the levels of Cu, Fe, Mg, Mn, Mo, and Zn in fourth instar H. virescens larvae. Conversely, in fifth instar H. virescens and both H. zea instar infections, no metal levels were significantly different between infected and uninfected larvae. In fourth instar H. virescens hemolymph, Cu, Fe, Mo, and Zn increased during development. Cu, Fe, Mg, Mn, Mo, and Zn...
The genome of a granulovirus isolated from the Old World bollworm, Helicoverpa armigera, was comp... more The genome of a granulovirus isolated from the Old World bollworm, Helicoverpa armigera, was completely sequenced. The size of the Helicoverpa armigera granulovirus (HearGV) genome is 169,794 nt containing 179 open reading frames (ORFs), making it the second largest baculovirus genome analyzed to date. The genomes of HearGV and the Xestia c-nigrum GV (XecnGV) exhibit extensive sequence similarity and co-linearity, with both genomes containing the same nine homologous regions (hrs) with conserved structure and locations and sharing 167 open reading frames (ORFs). Phylogenetic inference and pairwise analysis of Kimura-2-parameter nucleotide distances for the lef-8, lef-9, and granulin genes indicate that HearGV is part of a cluster of granuloviruses typified by XecnGV. The HearGV genome contains all 62 ORFs found in common among other fully sequenced lepidopteran baculovirus genomes, as well as seven ORFs unique to HearGV. In addition, HearGV and XecnGV genomes share 20 ORFs not found among other baculovirus genomes sequenced to date. In addition to possessing ten ORFs with sequence similarity to baculovirus repeated ORFs (bro), the HearGV genome contains members of two other gene families with homologues in ascovirus, nucleopolyhedrovirus, and entomopoxvirus genomes. Alignment of the HearGV and XecnGV genome sequences revealed that HearGV is missing approximately 16.6 kbp of XecnGV-homologous sequence and contains approximately 8.2 kbp of sequence not found in the XecnGV genome.
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