Project description:Honey bee drones, queens and workers have vastly different phenotypes. Here we profile the the expression level of mRNAs and microRNAs of honeybee, drones, queens and workers at the L5 larval stage (91 hours +/- 1).
Project description:Honey bee drones, queens and workers have vastly different phenotypes. Here we profile the the expression level of mRNAs and microRNAs of honeybee, drones, queens and workers at the L5 larval stage (91 hours +/- 1). For both mRNA and miRNA, we analyse five replicates for drones, queens and workers (15 replicates for mRNA and 15 for miRNA).
Project description:Honey bee colonies were maintained in an apiary at the University of British Columbia. During the summer of 2018, 40 queens were reared from a single colony and half were allowed to open mate, while the other half were kept as virgins in plastic queen cages. Two weeks after emergence, the virgin queens were given two, eight-minute carbon dioxide treatments on 2 sequential days, then re-introduced to their nucleus colonies. This process stimulates virgin queens to begin laying71, and we conducted these treatments in order to minimize the physiological differences between virgin and mated queens. Virgin and mated queens were retrieved from their nucleus colonies and half of each (10) were subjected to heat-shock (42 ͦC, 2 h), and then maintained at 30 ͦC for 2 d. The other half were held only at 30 ͦC for 2 d. Four to six weeks after mating, the queens were anesthetized with carbon dioxide, beheaded, then their spermathecae (including the tracheal net) were removed with fine forceps. Both ovaries were also removed and weighed. During the same summer, 200 drones from a different colony in the same apiary were collected and maintained in the laboratory overnight at ambient temperature with excess syrup (50% sucrose). The next day, semen was harvested with glass capillaries according to the methods described above. Because many drones were not sexually mature, 60 semen samples (out of the 200 drones) were collected. Capillaries were placed in petri dishes and half (30) were heat-shocked as described above, then kept at 25 ͦC for 2 d. The other half were only kept at 25 ͦC for 2 d. Ten samples from each experimental group were used for sperm viability assays as described above.
Project description:Mating is a complex process that causes many behavioral and physiological changes, but the factors triggering these changes and the underlying molecular processes are not well characterized. Honey bee queens provide a convenient system for dissecting these factors (e.g., physical manipulation, insemination volume, insemination substance) via instrumental insemination. We examined the effects of carbon dioxide (CO2), a commonly used anesthetic in instrumental insemination that causes changes similar to those observed after mating, and physical manipulation, which presumably mimics the act of copulation, on the brain transcriptional changes in honey bee queens. We found significant gene overlap between our study and previous mating studies in honey bee queens and Drosophila. This suggests that molecular pathways regulating the mating process are conserved across different mating regimes of honey bees as well as across insect orders.
Project description:We injected honey bee queens with a combination of BQCV&DWV-B, the same combination of virus that was inactivated with UV, or saline and monitored them in queen monitoring cages for 7 days before sacrificing them and performing proteomics on the hemolymph, ovaries, and eggs that were collected from the cages.
Project description:Our molecular understanding of honey bee cellular stress responses is incomplete. Previously, we sought to identify and began functional characterization of the components of the UPR in honey bees. We observed that UPR stimulation resulted in induction of target genes upon and IRE1 pathway activation, as assessed by splicing of Xbp1 mRNA. However, were not able to determine the relative role of the various UPR pathways in gene activation. Our understanding of honey bee signal transduction and transcriptional regulation has been hampered by a lack of tools. After using RNAseq to expand the known UPR targets in the bee, we use the Drosophila melanogaster S2 cell line and honey bee trans and cis elements to investigate the role of the IRE-1 pathway in the transcriptional activation of one of these targets, the honey bee Hsc70-3 gene. Using a luciferase reporter, we show that honey bee hsc70 promoter activity is inducible by UPR activation. In addition, we show that this activation is IRE1-dependent and relies on specific cis regulatory elements. Experiments using exogenous honey bee or fruit fly XBP1S proteins demonstrate that both factors can activate the Hsc70-3 promoter and further support a role for the IRE-1 pathway in control of its expression in the honey bee. By providing foundational knowledge about the UPR in the honey bee and demonstrating the usefulness of a heterologous cell line for molecular characterization of honey bee pathways, this work stands to improve our understanding of this critical species.
Project description:The present study is the first study to identify the involvement of circRNAs in the ovary activation and oviposition regulation processes in honey-bee queens.CircRNAs expresion profiles were examined in ovaries of virgin queens, egg-laying queens, egg-laying inhibited queens and egg-laying recovery queens.
Project description:Honey bee queens undergo dramatic behavioral (e.g., reduced sexual receptivity), physiological (e.g., ovary activation, ovulation, and modulation of pheromone production) and molecular changes after they complete mating. To elucidate how queen post-mating changes are influenced by seminal fluid, a non-spermatozoa-containing component of semen, we injected queens with semen or seminal fluid alone. We assessed queen sexual receptivity, ovary development, worker retinue response (which is influenced by queen pheromone production), and transcriptional changes in queen abdominal fat body and brain tissues. Injection with either seminal fluid or semen resulted in decreased sexual receptivity, increased attractiveness of queens to workers, and altered expression of several genes that are also regulated in naturally mated queens. The post-mating and transcriptional changes of queens receiving seminal fluid were not significantly different from queens treated with seminal fluid, suggesting that components in seminal fluid, such as seminal fluid proteins, are largely responsible for stimulating post-mating changes in queens.
Project description:Social caste determination in the honey bee is assumed to be determined by the dietary status of the young larvae and translated into physiological and epigenetic changes through nutrient-sensing pathways. We have employed microRNA gene-microarray, and observed that both worker jelly and royal jelly showed dynamic changes in miRNA content during the 4th to 6th day of larval development . Adding specific miRNAs to royal jelly elicited significant changes in queen larval mRNA expression and in morphological characters of the emerging adult queen bee. We propose that miRNAs in the nurse bee secretions constitute an additional element in the regulatory control of caste determination in the honey bee.