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.
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:Adult honey bee queens and workers drastically differ in ovary size. This adult ovary phenotype difference becomes established during the last two larval instars, when massive programmed cell death in the ovaries of worker larvae leads to the degeneration and removal of 95-99% of the ovariole anlagen. The higher juvenile hormone (JH) levels in queen larvae protect their ovaries against such degeneration. To gain insights into the molecular architecture underlying this divergence critical for adult caste fate we performed a microarray analysis contrasting RNA extracts from fourth and early fifth instar queen and worker ovaries. While for the fourth instar we found differential expression (log2FC > 1.0) for only nine genes, the number of differentially represented transcripts (DRTs) increased to 56 in early fifth instar ovaries. From these, 18 had their expression levels further analyzed by real-time PCR (RT-qPCR). For 13 of these the expression differed significantly between queen and worker ovaries at least one time point in development, and interestingly, genes with enzyme functions were overexpressed in workers, while genes related to transcription and signaling were so in queens. For the RT-qPCR confirmed genes we further analyzed their response to JH, revealing a significant up-regulation for two genes, one encoding a short chain dehydrogenase (SDR) and the other heat shock protein 90 (Hsp90). Five other genes, including Hsp60 and hexamerin 70b, were significantly down-regulated by JH. As SDR genes have previously come up as differentially expressed in different transcriptome assays in honey bee larvae, and heat shock proteins are involved in hormone responses, these are interesting candidates for further functional assays.
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. Among the specialized structures in workers the hind tibia forms the corbicula or the pollen basket, a smooth region surrounded by a row of a long scopal hairs, used for carrying pollen and other materials to the nest. This morphological trait and the respective behaviour are absent in queens. Herein we show details of the initial steps of hind legs morphogenesis in honeybee castes. Using results from the hybridization of whole genome-based oligonucleotide arrays with RNA samples from hind leg imaginal discs of pre-pupa honeybees of both castes we present a list of differentially expressed genes. Analysis used one dye-swap combination to compare workers and queens hind leg development at prepupal stages when juvenile hormone titers is much higher in queens
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. Among the specialized structures in workers the hind tibia forms the corbicula or the pollen basket, a smooth region surrounded by a row of a long scopal hairs, used for carrying pollen and other materials to the nest. This morphological trait and the respective behaviour are absent in queens. Herein we show details of the initial steps of hind legs morphogenesis in honeybee castes. Using results from the hybridization of whole genome-based oligonucleotide arrays with RNA samples from hind leg imaginal discs of pre-pupa honeybees of both castes we present a list of differentially expressed genes.
Project description:Epigenetic modifications are known to profoundly affect the development and behavior of social insects. In the well-known caste differentiation process of honeybee (Apis mellifera), female larvae with identical genomes are fed royal jellydifferently and develop into either normal workers or into very large, long-lived, and extremely fecund queens, and the queen-worker asymmetry of honeybee is known to be result largely to differential genomic imprinting during larval development that involves DNA methylation-based regulation. The discovery of reversible N6-methyladenosine (m6A) RNA methylation modification has defined a new era for RNA-metabolism-related genetic regulation, yet much remains unknown about m6A-mediated post-transcriptional regulatory mechanisms. Here, we report the first honeybee RNA m6A methylome. Specifically, we used the m6A-seq technique to examine the RNA m6A methylomes of honeybee larvae, including queen and worker larvae at multiple instar stages. We identified multiple conserved features of m6A methylation machinery and transcriptome-wide m6A distribution trends among insect species, and observed that m6A marks exert functions in regulating caste differentiation, with apparently particularly strong functional impacts on fifth instar worker larvae. Functional annotation of differentially methylated candidate caste-differentiation-related transcripts revealed many known regulators of caste differentiation (e.g. ILP-2, p110, PI3K, and JHAMT etc.) as well as the widely-studied Vitellogenin gene, which has not previously been implicated in caste differentiation. As ever-more regulatory roles for m6A marks are discovered, honeybees may become an excellent model studying the biology of such epi-transcriptomic regulatory systems, from embryonic development through holometabolous caste-specific development and on towards behavior and the emergent social hierarchies underlying eusociality in animals.
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:Female larvae of the honeybee (Apis mellifera) develop into either queens or workers depending on nutrition during larval development. This nutritional stimulus triggers different developmental trajectories, resulting in adults that differ in physiology, behaviour and life-span. To understand how these developmental trajectories are established we have undertaken a comprehensive analysis of differential gene expression throughout larval development.