Project description:Our aims in this study were: 1) to identify the miRNAs of the bumble bees Bombus terrestris and B. impatiens; 2) to compare the total numbers of miRNAs between both bumble bee species and between them and the honey bee, Apis mellifera; and 3) to test whether the sequences and expression patterns of miRNAs were conserved between species. To investigate each of these aims we used miRNA-seq (deep sequencing of miRNA-enriched libraries) in B. terrestris, and bioinformatics prediction programs to identify miRNAs in both Bombus species. We identified 131 miRNAs in B. terrestris, and 114 in B. impatiens; of these, 17 were new miRNAs that had not previously been sequenced in any species. We found a striking level of difference in the miRNAs present between Bombus and A. mellifera, with 103 miRNAs in A. mellifera not being present in the genomes of the two bumble bees.
Project description:Our aims in this study were: 1) to identify the miRNAs of the bumble bees Bombus terrestris and B. impatiens; 2) to compare the total numbers of miRNAs between both bumble bee species and between them and the honey bee, Apis mellifera; and 3) to test whether the sequences and expression patterns of miRNAs were conserved between species. To investigate each of these aims we used miRNA-seq (deep sequencing of miRNA-enriched libraries) in B. terrestris, and bioinformatics prediction programs to identify miRNAs in both Bombus species. We identified 131 miRNAs in B. terrestris, and 114 in B. impatiens; of these, 17 were new miRNAs that had not previously been sequenced in any species. We found a striking level of difference in the miRNAs present between Bombus and A. mellifera, with 103 miRNAs in A. mellifera not being present in the genomes of the two bumble bees. miRNA profiles of Bombus terrestris at two developmental stages in larvae. This submission represents 'Bombus terrestris' component of study.
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:Research on forms of memory in innate immune systems has recently gained momentum with the study of trained immunity in vertebrates and immune priming in invertebrates. Immune priming provides protection against previously encountered pathogens. However, causes and mechanisms of immune priming are still not well understood in most organisms. In this work, we combine RNA sequencing with transmission electron microscopy to investigate the dynamic processes during priming in the gut of a well-established model for oral immune priming, consisting of the host Tribolium castaneum and its entomopathogen Bacillus thuringiensis tenebrionis (Btt). We show that priming with specific, non-infectious pathogen-derived cues causes damage in the gut of T. castaneum larvae, which leads to an early physiological stress response as well as the upregulation of a specific set of immune genes. This response diminishes over time yet enables the gut to upregulate genes known to interfere with Btt virulence when T. castaneum larvae are later exposed to infectious Btt spores. These insights contribute to our understanding of immune priming as a dynamic process where cellular responses in concert with specific gene regulation prepare the gut tissue and thereby enables a more efficient protection against infection. Such work can further help us understand the origin and mechanism of innate immune memory.
Project description:BACKGROUND: Social insects, such as honey bees, use molecular, physiological and behavioral responses to combat pathogens and parasites. The honey bee genome contains all of the canonical insect immune response pathways, and several studies have demonstrated that pathogens can activate expression of immune effectors. Honey bees also use behavioral responses, termed social immunity, to collectively defend their hives from pathogens and parasites. These responses include hygienic behavior (where workers remove diseased brood) and allo-grooming (where workers remove ectoparasites from nestmates). We have previously demonstrated that immunostimulation causes changes in the cuticular hydrocarbon profiles of workers, which results in altered worker-worker social interactions. Thus, cuticular hydrocarbons may enable workers to identify sick nestmates, and adjust their behavior in response. Here, we test the specificity of behavioral, chemical and genomic responses to immunostimulation by challenging workers with a panel of different immune stimulants (saline, Sephadex beads and Gram-negative bacteria E. coli). RESULTS: While only bacteria-injected bees elicited altered behavioral responses from healthy nestmates compared to controls, all treatments resulted in significant changes in cuticular hydrocarbon profiles. Immunostimulation caused significant changes in expression of hundreds of genes, the majority of which have not been identified as members of the canonical immune response pathways. Furthermore, several new candidate genes that may play a role in cuticular hydrocarbon biosynthesis were identified. Finally, we identified common genes regulated by pathogen challenge in honey bees and other insects, suggesting that immune responses are conserved at the molecular level. CONCLUSIONS: These studies suggest that honey bee genomic responses to immunostimulation are substantially broader than expected, and may mediate the behavioral changes associated with social immunity by orchestrating changes in chemical signaling.