Project description:In this study we addressed whether the transcriptome profile in the honey bee brain is similar for two major parasites of honey bee, Varroa destructor and Nosema ceranae. Honey bees parasitized by these two parasites show accelerated behavioral maturation and deficiences in orientation and learning/memory that we hoped to characterized at the transcriptomic level. honey bee adults infested by Varroa destructor or Nosema ceranae compared to control bees, in duplicate
Project description:The Varroa mite represents the main threat of honey bees (Apis mellifera). Bees from some colonies can limit the proliferation of this parasite by detecting and removing parasitized brood, such behavior is defined as Varroa sensitive Hygiene (VSH). This is an important issue for selecting colonies that can survive Varroa outbreaks. We therefore study the molecular meachnisms underlying this behavior by comparing the antennae transcriptomic profile of VSH and non-VSH bees. Those profiles were further compared to to the profiles of nurses and forager profiles involved in brood care and food collection, respectively.
Project description:Experiment was designed (i) to analyse the strain composition of Deformed wing virus (DWV) populations in covertly and overtly infected honeybees (Apis mellifera) from Varroa-free and Varroa-infested colonies, and (ii) to determine abundance of the DWV strains following direct injection of the DWV preparations from covertly and overtly infected bees to the bee pupae haemolymph in the absence of Varroa destructor mites. Experiment included isolation of DWV preparations from the following bees: covertly-infected bees from Varroa-free colony, covertly infected bees exposed orally to the Varroa-selected DWV strains, and the overtly infected Varroa-exposed bees. Honeybee pupae were experimentally injected with those DWV preparations and sampled 4 days post injection following development of overt DWV infection. A series of the DWV cDNA fragment covering complete DWV genomic RNA sequences were amplified by RT-PCR using RNA extracted from virus preparations and the injected pupae. The cDNA preparations were sequenced using next generation(Illumina HighSeq 2000) paired-end sequencing to obtain data on the DWV strain composition.
Project description:To study the underlying molecular mechanisms during the Varroa destructor life cycle, we carried out transcriptomic profiling of seven stages: young mites (collected from P8 to P9 brood cells), phoretic mites (collected on adult bees), arresting mites (collected in unsealed L5 brood cells), pre-laying mites (collected from sealed brood cells containing moving larva), laying mites (collected from sealed brood cells containing pre-pupae), post-laying mites (collected from capped brood cells containing purple-eye and white-body pupae P5), emerging mites (collected from P8 to P9 brood cells). In addition, we sampled non-reproducing mites (collected from P5 brood cells, but without offspring), males (collected from P8 to P9 brood cells), and phoretic mites artificially reared in cages with adult bees. This study was performed using Apis mellifera L. honey bee colonies naturally infested by Varroa destructor mites. Adult mites were collected from 4 unrelated colonies.
Project description:The mite Varroa destructor is currently the greatest threat to apiculture as it is causing a global decrease in honey bee colonies. However, it rarely causes serious damage to its native hosts, the eastern honey bees Apis cerana. To better understand the mechanism of resistance of A. cerana against the V. destructor mite, we profiled the metabolic changes that occur in the honey bee brain during V. destructor infestation. Brain samples were collected from infested and control honey bees and then measured using an untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based global metabolomics method, in which 7918 and 7462 ions in ESI+ and ESI- mode, respectively, were successfully identified. Multivariate statistical analyses were applied, and 64 dysregulated metabolites, including fatty acids, amino acids, carboxylic acid, and phospholipids, amongst others, were identified. Pathway analysis further revealed that linoleic acid metabolism; propanoate metabolism; and glycine, serine, and threonine metabolism were acutely perturbed. The data obtained in this study offer insight into the defense mechanisms of A. cerana against V. destructor mites and provide a better method for understanding the synergistic effects of parasitism on honey bee colonies.
Project description:Extensive annual losses of honey bees (Apis mellifera L.) represent a global problem for agriculture and biodiversity. The parasitic mite Varroa destructor in association with viral co-infections plays a key role in this phenomenon; however, the precise mechanisms are still unclear. We employed a unique combination of transcriptomic, proteomic, metabolomic, and functional analyses to elucidate the effects of Varroa parasitisation. We focused on complex differences between parasitised and unparasitised ten-days old honey bee workers collected from identical colonies before overwintering. Honey bees exposed to mite parasitation during their development revealed alterations in transcriptome and proteome related to immunity, oxidative stress, olfactory recognition, metabolism of sphingolipids and RNA regulatory mechanisms. Specifically, immune reactions and sphingolipids metabolism were strongly up-regulated in parasitised honey bees; whereas olfactory recognition and oxidative stress pathways were down-regulated compared to unparasitised bees. Additionally, the metabolomic analysis confirmed the depletion of nutrients, decreased energy stores and generally disrupted metabolism of parasitised workers, as previously reported. By virtue of comprehensive omics-based analysis, we define the key changes in the honey bee facing Varroa parasitism and suggest possible mechanisms underlying its detrimental effects. This study provides a theoretical basis for future efforts in efficient control strategies against Varroa mites.
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: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.
Project description:In this study we addressed whether the transcriptome profile in the honey bee brain is similar for two major parasites of honey bee, Varroa destructor and Nosema ceranae. Honey bees parasitized by these two parasites show accelerated behavioral maturation and deficiences in orientation and learning/memory that we hoped to characterized at the transcriptomic level.
Project description:Experiment was designed to study the effect of Deformed wing virus (DWV) and the mite Varroa destructor on global gene expression using microarray transcriptional profiling in developing worker honeybee (Apis mellifera). Newly hatched bee larvae (day 3 of bee development) were transferred from a Varroa-free colony with low DWV levels to a Varroa-infested colony with high levels of DWV in bees and Varroa mites. All transferred larvae were receiving the DWV strains present in this Varroa-infested colony with the food delivered by the nurse bees until their capping (day 8). About half of these larvae were capped with Varroa mite and were subjected to the mite piercing and feeding on their haemolymph during pupal development until sampling at purple eye stage (day 14). Exposure to the mite piercing and feeding resulted in about 1000-fold increase of the DWV levels in the majority of the mite-exposed pupae compared to the control pupae and the pupae not exposed to Varroa mites.