Project description:There were important gaps in our knowledge of Israeli acute paralysis virus (IAPV), when IAPV was tightly linked to bee Colony Collapse Disorder (CCD), the mysterious disease that, starting in 2006-2007, has been wiping out honey bees in the US. To fill in these gaps we studied the molecular basis of transmission, pathogenesis, and genetic diversity of IAPV infection in honey bees. We investigated the impact of IAPV infection on colony losses and host transcriptional response to IAPV infections, and exploited the potential of RNAi-based strategies for treating viral diseases in honey bees. Our study clearly shows that IAPV has become established as a persistent infection and is highly prevalent in the honey bee population. The existence of both horizontal and vertical transmission pathways of the virus likely accounts for the high prevalence of IAPV in bees. While IAPV is probably not the only culprit responsible for CCD, its ability to cause increased mortality in honey bees is firmly demonstrated. The phenotypic differences in pathology among different strains of IAPV may be due to their high level of standing genetic variation. The JAK-STAT pathway, along with other signaling events such as mTOR and MAPK pathways, likely involves honey bees’ antiviral immune responses to the IAPV infection. The identification of IAPV-encoded putative suppressor of RNAi and evidence that silencing the RNAi suppressor led to a significant reduction in IAPV replication in infected bees illustrates the therapeutic potential of targeting viral suppressor protein to reduce virus replication. Our study gives direction for developing strategies to reduce colony losses due to viral diseases.
2014-04-08 | GSE46278 | GEO
Project description:Complete coding genome sequence of Black queen cell virus isolated from honey bees in Italy
Project description:There were important gaps in our knowledge of Israeli acute paralysis virus (IAPV), when IAPV was tightly linked to bee Colony Collapse Disorder (CCD), the mysterious disease that, starting in 2006-2007, has been wiping out honey bees in the US. To fill in these gaps we studied the molecular basis of transmission, pathogenesis, and genetic diversity of IAPV infection in honey bees. We investigated the impact of IAPV infection on colony losses and host transcriptional response to IAPV infections, and exploited the potential of RNAi-based strategies for treating viral diseases in honey bees. Our study clearly shows that IAPV has become established as a persistent infection and is highly prevalent in the honey bee population. The existence of both horizontal and vertical transmission pathways of the virus likely accounts for the high prevalence of IAPV in bees. While IAPV is probably not the only culprit responsible for CCD, its ability to cause increased mortality in honey bees is firmly demonstrated. The phenotypic differences in pathology among different strains of IAPV may be due to their high level of standing genetic variation. The JAK-STAT pathway, along with other signaling events such as mTOR and MAPK pathways, likely involves honey bees’ antiviral immune responses to the IAPV infection. The identification of IAPV-encoded putative suppressor of RNAi and evidence that silencing the RNAi suppressor led to a significant reduction in IAPV replication in infected bees illustrates the therapeutic potential of targeting viral suppressor protein to reduce virus replication. Our study gives direction for developing strategies to reduce colony losses due to viral diseases. Adult worker bees and brood were collected from colonies that were declining and identified with IAPV infections and its control with 6 replications per group.
Project description:Here, we examined the transcriptional and epigenetic (DNA methylation) responses to viral infection in honey bee workers. One-day old worker honey bees were fed solutions containing Israeli Acute Paralysis Virus (IAPV), a virus which causes muscle paralysis and death and has previously been associated with colony loss. Uninfected control and infected, symptomatic bees were collected within 20-24 hours after infection. Worker fat bodies, the primary tissue involved in metabolism, detoxification and immune responses, were collected for analysis. We performed transcriptome- and bisulfite-sequencing of the worker fat bodies to identify genome-wide gene expression and DNA methylation patterns associated with viral infection. There were 753 differentially expressed genes (FDR<0.05) in infected versus control bees, including several genes involved in epigenetic and antiviral pathways. DNA methylation status of 156 genes (FDR<0.1) changed significantly as a result of the infection, including those involved in antiviral responses in humans. There was no significant overlap between the significantly differentially expressed and significantly differentially methylated genes, and indeed, the genomic characteristics of these sets of genes were quite distinct. Our results indicate that honey bees have two distinct molecular pathways, mediated by transcription and methylation, that modulate protein levels and/or function in response to viral infections. Examination of epigenomic and transcriptomic antiviral responses to Israeli Acute Paralysis Virus in honey bees
Project description:Experimental infection of (2 days old) adult honey bee workers (30 bees per replicates, 3 replicates per treatments, from 3 different colonies (one colony per cage for each treatment)) with 10^9 genome equivalent of Black Queen Cell Virus (BQCV) in 10µl of sugar solution and/or 10^5 fresh Nosema ceranae spores (control bees were given a similar bee extract in PBS, without pathogen). Bees were kept in cages of 30 bees in incubator (30°C/50%RH). At day 13 p.i., bees were flash frozen, and stored at -80°C.
Project description:Purpose: Parts of Europe and the United States have witnessed dramatic losses in commercially managed honey bees over the past decade to what is considered an unsustainable extent. The large-scale loss of honey bees has considerable implications for the agricultural economy because honey bees are one of the leading pollinators of numerous crops. Honey bee declines have been associated with several interactive factors. Poor nutrition and viral infection are two environmental stressors that pose heightened dangers to honey bee health. Methods: We used RNA-sequencing to examine how monofloral diets (Rockrose and Chestnut) and Israeli acute paralysis virus inoculation influence gene expression patterns in honey bees. Results: We found a considerable nutritional response, with almost 2,000 transcripts changing with diet quality. The majority of these genes were over-represented for nutrient signaling (insulin resistance) and immune response (Notch signaling and JaK-STAT pathways). Somewhat unexpectedly, the transcriptomic response to viral infection was fairly limited. We only found 43 transcripts to be differentially expressed, some with known immune functions (argonaute-2), transcriptional regulation, and muscle contraction. We created contrasts to determine if any protective mechanisms of good diet were due to direct effects on immune function (resistance) or indirect effects on energy availability (tolerance). A similar number of resistance and tolerance candidate differentially expressed genes were found, suggesting both processes may play significant roles in dietary buffering from pathogen infection. We also compared the virus main effect in our study (polyandrous colonies) to that obtained in a previous study (single-drone colonies) and verified significant overlap in differential expression despite visualization methods showing differences in the noisiness levels between these two datasets. Conclusions: Through transcriptional contrasts and functional enrichment analysis, we add to evidence of feedbacks between diet and disease in honey bees. We also show that comparing results derived from polyandrous colonies (which are typically more natural) and single-drone colonies (which usually yield more signal) may allow researchers to identify transcriptomic patterns in honey bees that are concurrently less artificial and less noisy. Altogether, we hope this work underlines possible merits of using data visualization techniques and multiple datasets when interpreting RNA-sequencing studies.
Project description:Here, we examined the transcriptional and epigenetic (DNA methylation) responses to viral infection in honey bee workers. One-day old worker honey bees were fed solutions containing Israeli Acute Paralysis Virus (IAPV), a virus which causes muscle paralysis and death and has previously been associated with colony loss. Uninfected control and infected, symptomatic bees were collected within 20-24 hours after infection. Worker fat bodies, the primary tissue involved in metabolism, detoxification and immune responses, were collected for analysis. We performed transcriptome- and bisulfite-sequencing of the worker fat bodies to identify genome-wide gene expression and DNA methylation patterns associated with viral infection. There were 753 differentially expressed genes (FDR<0.05) in infected versus control bees, including several genes involved in epigenetic and antiviral pathways. DNA methylation status of 156 genes (FDR<0.1) changed significantly as a result of the infection, including those involved in antiviral responses in humans. There was no significant overlap between the significantly differentially expressed and significantly differentially methylated genes, and indeed, the genomic characteristics of these sets of genes were quite distinct. Our results indicate that honey bees have two distinct molecular pathways, mediated by transcription and methylation, that modulate protein levels and/or function in response to viral infections.
Project description:The microsporidia Nosema ceranae are intracellular parasites that proliferate in the midgut epithelial cells of honey bees (Apis mellifera). To analyze the pathological effects of those microsporidia, we orally infected honey bee workers 7 days after their emergence. Bees were flash frozen 15 days after the infection. Then, the effects on the gut ventriculi were analyzed and compared to non-infected (control) bees.
Project description:Background: Honey bee is a major insect used for pollination of a number of commercial crops worldwide. However, the number of managed honey bee colonies has recently declined in several countries, and a number of possible causes are proposed. Although the use of honey bees for pollination can be considered as disruption of the habitat, its effects on honey bees' physiology have never been addressed. In Japan, more than 100 thousands colonies are annually used for pollination, and intriguingly 80% of them are used in greenhouses. Recently, honey bee colonies have often collapsed when they are introduced into greenhouses. Thus, to suppress colony collapses and maintain the number of worker bees in the colonies are essential for successful long-term pollination in greenhouses and recycling honey bee colonies.