Project description:Sex determination in the honeybee (Apis mellifera) is governed by the queen-controlled unfertilization or fertilization of embryo, though the mechanisms of determination are poorly understood. Here, we obtained the transcriptomes from individual worker and drone embryo during the embryonic development (day 1 to day 3). We show that transcriptional difference between worker and drone embryo is very small during the first day of hatching, during which sex-determinant gene csd expresses similarly. Differential transcription between worker and drone embryo bursts at day 2, among which csd is induced in worker embryo at day 2 and sex-lethal gene sxl is repressed in male embryo. An unexpected global regulation of alternative splicing accompanies the honeybee embryonic development, and male and worker embryo show distinct regulatory patterns and mechanisms. This study suggests the honeybee sex determination is more globally controlled at both the transcriptional and alternative splicing levels.
Project description:The honeybee brain is comprised of a nervous system that sufficiently regulates this life transition. Knowledge about how protein phosphorylation functions in regards to the neurobiological activities in the honeybee brain to drive the age-specific labor division is still lacking. Protein phosphorylation, the most common post-translational modification (PTM), is a key switch for rapid on-off control of signaling cascades that regulate cell differentiation and development, enzyme activity and metabolic maintenance in living cells. A fundamental mechanism for regulating signaling network and protein activity is the covalent PTM of serine (Ser), threonine (Thr), and tyrosine (Tyr) residues with phosphate. Fortunately, because of advances in phosphopeptide enrichment and improvements in mass spectrometry (MS) instrumentation and methods, phosphoproteomics has enabled large-scale identification of protein phosphorylation sites and phosphorylation networks in biological samples. Although the proteome has been mapped in the brain of nurse and forager bees, knowledge about age-specific effects of phosphorylation regulation on proteins in the honeybee brain is still lacking. Moreover, information in regards to the honeybee phosphoproteome is also very limited. Only very recently, in-depth phosphoproteomics analyses of protein phosphorylation networks in the hypopharyngealgland of the honeybee have been reported. Although the phosphoproteome analyses during the development of brood and salivary glands has been reported, only very limited proteins were phosphorylated and phosphorylation sites of those phosphoproteins were not assigned. Therefore, a comprehensive characterization of phosphoproteomics and changes in the brains of nurse and forager bees is key to understand the phosphorylation events underlying age-specific physiology to achieve the completion of biological missions in this well-organized social community of the honeybee. Honeybee (A. m. ligustica) colonies used for sampling were raised at the apiary of the Institute of Apicultural Research, Chinese Academy of Agricultural Science, Beijing. Newly emerged (<12 h after emergence) worker bees were marked on their thoraxes and placed back into the colonies to develop and then the marked nurse and forager bees were collected on days 10 and 20, respectively. There were 150 bees sampled from each of the five colonies which have queens at the same age. In brief, for each time point, worker bees were sampled from five colonies, and pooled all samples for further analysis. This procedure was repeated three times, so that we finally ended up with three independent biological replicates per time point, each consisting of 150 honeybees. Then their brains were dissected, and the brain samples were pooled and stored at −80 °C for further analysis. All the colonies were managed with almost identical population, food, and brood during the nectar flow of chaste berry (Vitexnegundo L.) in June.
Project description:Female honeybees are specified as workers or queens based on diet during early development. Workers are essentially sterile with a reduced number of ovarioles and no spermatheca. In the presence of the queen (queen mandibular pheromone) and her brood, worker ovaries are kept in an inactive quiescent state. If the queen is removed, or lost, worker bees are able to sense this change in their environment and their ovaries undergo complete remodelling producing unfertilised haploid eggs that will produce male (drone bees). In this study we analyse gene expression in queen, worker, and laying worker ovaries using RNA-seq and explore differences in the chromatin landscape (focussing on H3K27me3).
Project description:Effect of genotype (wildtype vs. anarchist) on gene expression in developing (four-day-old) honeybee worker brains. Goal of experiment is to identify genes associated with ovary activation during worker development. These genes are hypothesised to be candidates for the regulation of worker sterility.
Project description:Effect of genotype (wildtype vs. anarchist) on gene expression in developing (four-day-old) honeybee worker abdomens. Goal of experiment is to identify genes associated with ovary activation during worker development. These genes are hypothesised to be candidates for the regulation of worker sterility.
Project description:We use chromatin immunoprecipitation and high throughput sequencing to produce the first genome-wide maps of chromatin structure in the honeybee at a key larval stage where developmental canalization into queen or worker is irreversible. We find extensive genome-wide differences in H3K4me3, H3K27ac and H3K36me3, many of which correlate with caste-specific transcription. Furthermore, we identify H3K27ac as a key chromatin modification that most robustly defines caste and suggest that these regions may harbour caste-specific cis-acting elements such as enhancers.
Project description:As a matter of fact, honeybees are vital for the pollination of more than 80 crops of agricultural interest. However, population decline has become an important global issue causing significant concerns among agricultural experts and the broader public. For this, parasites are known to be the major culprits responsible for the losses of millions of honeybee colonies so far. Among these parasites, Varroa destructor has been identified as a major cause for global losses in Western honeybee (Apis mellifera) colonies. Hygienic behavior (HB), on the other hand, is a collective response by adult honeybees to defend against parasites and diseases that is known to involve in resistance towards Varroosis. Even with the efforts made to elucidate the molecular mechanism underlying HB, it is still not understood. In our study, we have studied the proteomic correlates to HB using a honeybee line (selected for Varroa-specific HB for over a decade in Germany). We sampled individual worker bees from this line that showed HB after closer infrared video observations and compared the proteomes of their mushroom bodies and antennae with those of workers that came from the same set of colonies but didn't show the behaviour. Furthermore, we compared the pupal hemolymph for worker bees of the selected HB line and a control line using state-of-the art techniques of proteomics. We identified a total of 8609 proteins (covered >55% of the honeybee proteome) from these three honeybee tissues. This is the most comprehensive proteomic study of the honeybee HB to date, and the first to focus on individual bees expressing Varroa-specific HB. These results have significantly advanced our knowledge on the biology underlining HB to a new level. The uniquely found functional classes and pathways by the proteins identified in each tissue suggest that hygienic bees have shaped distinct proteome settings to underpin the HB. Moreover, during analysis of pupal hemolymph proteome, the HB-line has adapted a unique strategy to boost an individual and social immunity and drove pupal organogenesis via energy metabolism and protein biosynthesis. Moreover, in the mushroom bodies of different HB phenotypic worker bees, the hygienic bees have enhanced their neuronal sensitivity to promote the execution of HB by activation of synaptic vesicles and calcium channel activities. Moreover, in the antennae of two HB phenotypic worker bees, the hygienic bees have demonstrated strengthening of their sensitivity associated with olfactory senses and signal transmissions, which is important to input a strong signal to the mushroom bodies and initiate HB. In conclusion, our novel findings have significantly extended our understandings of the molecular mechanisms that underline the HB to combat Varroa infestation. Furthermore, we identified a wide array of novel markers that are useful for accelerating marker associated selection of HB to aid in the natural resistance to a parasite blamed for a global decline in honeybee health.
Project description:In Apis mellifera, the female eggs can develop into workers or queen depending on the diet offered during early development. The outputs of the developed honeybee females are two morphs with particular morphological traits and related physiology. The differential feeding regime experienced by the queen and the worker larvae of the honeybee Apis mellifera shapes a complex endocrine response cascade that ultimately sets up differences in brain morphologies. Herein we report on aspects of brain morphogenesis during larval development and the brain gene expression signature of fourth instar larvae (L4) of both castes, a developmental stage characterized by the greatest differences in juvenile hormone (JH) titers between castes Using results from the hybridization of whole genome-based oligonucleotide arrays with RNA samples from brain of fourth instar larvae honeybees of both castes we present a list of differentially expressed genes.
Project description:Female honeybees are specified as workers or queens based on diet during early development. Workers are essentially sterile with a reduced number of ovarioles and no spermatheca. In the presence of the queen (queen mandibular pheromone) and her brood, worker ovaries are kept in an inactive quiescent state. If the queen is removed, or lost, worker bees are able to sense this change in their environment and their ovaries undergo complete remodeling producing unfertilized haploid eggs that will produce male (drone bees). In this study we analyze gene expression in queen, worker, and laying worker ovaries using RNA-seq and explore differences in the chromatin landscape (focusing on H3K27me3).
Project description:In Apis mellifera, the female eggs can develop into workers or queen depending on the diet offered during early development. The outputs of the developed honeybee females are two morphs with particular morphological traits and related physiology. The differential feeding regime experienced by the queen and the worker larvae of the honeybee Apis mellifera shapes a complex endocrine response cascade that ultimately sets up differences in brain morphologies. Herein we report on aspects of brain morphogenesis during larval development and the brain gene expression signature of fourth instar larvae (L4) of both castes, a developmental stage characterized by the greatest differences in juvenile hormone (JH) titers between castes Using results from the hybridization of whole genome-based oligonucleotide arrays with RNA samples from brain of fourth instar larvae honeybees of both castes we present a list of differentially expressed genes. Analysis used one dye-swap combination to compare workers and queens brain development at fourth instar larvae when juvenile hormone titers is higher in queens.