Project description:Sterols are essential nutrients for insects because, in contrast to mammals, no insect (or arthropod for that matter) can synthesize sterols de novo. Cholesterol is the most common sterol in insects, but it is not found in plants in large quantities; plant-feeding insects typically generate their cholesterol by metabolizing phytosterols. However, different plants species can contain different types of phytosterols, and some phytosterols are not readily converted to cholesterol. In this study we examined, using artificial diets containing single sterols, how typical (cholesterol and stigmasterol) and atypical (cholestanol and cholestanone) sterols/steroids affect the performance of a generalist caterpillar (Helicoverpa zea), restricting this analysis to midgut tissue because this is where sterol/steroid absorption occurs, and the midgut is the putative site of dietary sterol/steroid metabolism. In general, H. zea performed best on the cholesterol and stigmasterol treatments; performance was reduced on cholestanol, and was very poor on cholestanone. We compared the transcript profiles of larval guts in response to differentially suitable sterols, using the optimal sterol, cholesterol, as a control, using a two-color reference design microarray experiment. Midgut gene expression patterns differed between the treatments; relative to cholesterol, differences were lowest on the stigmasterol treatment, intermediate on the cholestanol treatment, and greatest on the cholestanone treatment. Transcriptional profiling comparing Helicoverpa zea gut tissue from third instar larvae exposed to four different dietary sterols, namely Cholesterol (CON), Cholestanol (ChStanol), Cholestan-3-one (Ch3one) and Stigmasterol (Stigma). Two-color reference design. Biological replicates: 4 (5 individuals per replicate). 12 samples total.
Project description:Sterols are essential nutrients for insects because, in contrast to mammals, no insect (or arthropod for that matter) can synthesize sterols de novo. Cholesterol is the most common sterol in insects, but it is not found in plants in large quantities; plant-feeding insects typically generate their cholesterol by metabolizing phytosterols. However, different plants species can contain different types of phytosterols, and some phytosterols are not readily converted to cholesterol. In this study we examined, using artificial diets containing single sterols, how typical (cholesterol and stigmasterol) and atypical (cholestanol and cholestanone) sterols/steroids affect the performance of a generalist caterpillar (Helicoverpa zea), restricting this analysis to midgut tissue because this is where sterol/steroid absorption occurs, and the midgut is the putative site of dietary sterol/steroid metabolism. In general, H. zea performed best on the cholesterol and stigmasterol treatments; performance was reduced on cholestanol, and was very poor on cholestanone. We compared the transcript profiles of larval guts in response to differentially suitable sterols, using the optimal sterol, cholesterol, as a control, using a two-color reference design microarray experiment. Midgut gene expression patterns differed between the treatments; relative to cholesterol, differences were lowest on the stigmasterol treatment, intermediate on the cholestanol treatment, and greatest on the cholestanone treatment.
Project description:This SuperSeries is composed of the following subset Series: GSE34344: Transcriptional analysis of physiological pathways in a generalist herbivore: responses to different host plants and plant structures by the cotton bollworm (CBW) Helicoverpa armigera [CottonStructures] GSE34346: Transcriptional analysis of physiological pathways in a generalist herbivore: responses to different host plants and plant structures by the cotton bollworm (CBW) Helicoverpa armigera [DifferentHost] Refer to individual Series
Project description:The Helicoverpa armigera single-capsid nucleopolyhedrovirus (HaSNPV) can be propagated using H. zea insect cell cultures, for use as a biopesticide against Heliothine agricultural pests.This study sequenced, assembled and functionally annotated 29,586 transcript sequences from cultured H. zea cells using Illumina 100 bps and paired-end transcriptome sequencing (RNA-seq). From these sequences, a genome-scale microarray platform was constructed and validated for effective expression analysis of H. zea genes. This array also included probes for all HaSNPV genes, thereby allowing virus and host gene changes to be monitored simultaneously.
Project description:A custom microarray, based on deep transcriptome sequencing ((GEO accession number: GSE34418), was used to simultaneously investigate expression of over 24,000 Helicoverpa zea insect transcripts and 134 H. armigera nucleopolyhedrovirus (HearNPV) genes throughout the infection process at 0, 12, 24 and 48 hours post infection
