Germ cell development in the Honeybee (Apis mellifera); Vasa and Nanos expression

BACKGROUND: Studies of specification of germ-cells in insect embryos has indicated that in many taxa the germ cells form early in development, and their formation is associated with pole plasm, germ plasm or an organelle called the oosome. None of these morphological features associated with germ cell formation have been identified in the Honeybee Apis mellifera. In this study I report the cloning and expression analysis of Honeybee homologues of vasa and nanos, germ cell markers in insects and other animals. RESULTS: Apis vasa and nanos RNAs are present in early honeybee embryos, but the RNAs clear rapidly, without any cells expressing these germ cell markers past stage 2. These genes are then only expressed in a line of cells in the abdomen from stage 9 onwards. These cells are the developing germ cells that are moved dorsally by dorsal closure and are placed in the genital ridge. CONCLUSION: This study of the expression of germ cell markers in the honeybee implies that in this species either germ cells are formed by an inductive event, late in embryogenesis, or they are formed early in development in the absence of vasa and nanos expression. This contrasts with germ cell development in other members of the Hymenoptera, Diptera and Lepidoptera

Participatory healthcare service design and innovation

This paper describes the use of Experience Based Design (EBD), a participatory methodology for healthcare service design, to improve the outpatient service for older people at Sheffield Teaching Hospitals. The challenges in moving from stories to designing improvements, co-designing for wicked problems, and the effects of participants' limited scopes of action are discussed. It concludes by proposing that such problems are common to participatory service design in large institutions and recommends that future versions of EBD incorporate more tools to promote divergent thinking

Tailless patterning functions are conserved in the honeybee even in the absence of Torso signaling

AbstractIn Drosophila, the maternal Torso terminal signaling pathway activates expression of the gene tailless (tll), which is required for the patterning of anterior and posterior termini. We cloned the honeybee orthologue of tll (Am-tll) and found that embryonic expression of Am-tll resembles that of Drosophila, with expression in triangular anterior dorsal–lateral domains and a posterior cap. Functional studies revealed that Am-tll has an essential role in patterning the posterior terminal segments and the brain, similar to the activity of tll in other insects. As the honeybee genome lacks many of the components of the Torso pathway required for terminal patterning, we investigated the regulation of honeybee tailless (Am-tll). Am-tll is expressed maternally and, in the honeybee ovary, Am-tll mRNA becomes localized to the dorsal side of the oocyte, a process requiring the actin cytoskeleton. This RNA becomes redistributed in early embryos to a posterior domain. We also show that the activation of the anterior domain of Am-tll is dependent on honeybee orthodenticle-1. Together these findings indicate major differences in post-transcriptional regulation of tailless in the honeybee compared to other insects but that this regulation leads to a conserved expression pattern. These results provide an example of an early event in development evolving and yet still producing a conserved output for the rest of development to build upon

Pervasive healthcare in lived experience : thinking beyond the home : position paper for workshop on pervasive healthcare in the home.

The National Health Service (NHS) in the UK, like many other public heath services worldwide, is facing a number of key challenges. Among them are an ageing population and a rising incidence of chronic health conditions. This situation requires a radical re-examination of how people manage their health and their healthcare in ways that challenge the relationship between people and healthcare services. Combining this observation with the opportunities afforded by pervasive information and communication technologies, we argue that design research should reach beyond simply locating devices and services to offer healthcare ‘in the home’ and should examine this broader agenda. Rather than focussing design discourse on the specifics of one location, we should adopt a holistic view, beginning from people’s lived experience. In this position paper we describe the User-Centred Healthcare Design (UCHD) project, a 5-year collaboration between universities and NHS Trusts in South Yorkshire, UK. We suggest that new models of healthcare that re-define the institutional and social context of care are required if we are to meet the challenge of chronic illness. We describe our progress to date on the UCHD project, our commitment to placing patient experience at the centre of design, and our initial experiences of using an experience-based co-design method to improve outpatient services in a Sheffield hospital

Evolution of the insect Sox genes

<p>Abstract</p> <p>Background</p> <p>The <it>Sox </it>gene family of transcriptional regulators have essential roles during development and have been extensively studied in vertebrates. The mouse, human and <it>fugu </it>genomes contain at least 20 <it>Sox </it>genes, which are subdivided into groups based on sequence similarity of the highly conserved HMG domain. In the well-studied insect <it>Drosophila melanogaster</it>, eight <it>Sox </it>genes have been identified and are involved in processes such as neurogenesis, dorsal-ventral patterning and segmentation.</p> <p>Results</p> <p>We examined the available genome sequences of <it>Apis mellifera, Nasonia vitripennis, Tribolium castaneum</it>, <it>Anopheles gambiae </it>and identified <it>Sox </it>family members which were classified by phylogenetics using the HMG domains. Using <it>in situ </it>hybridisation we determined the expression patterns of eight honeybee <it>Sox </it>genes in honeybee embryo, adult brain and queen ovary. <it>AmSoxB </it>group genes were expressed in the nervous system, brain and Malphigian tubules. The restricted localization of <it>AmSox21b </it>and <it>AmSoxB1 </it>mRNAs within the oocyte, suggested a role in, or that they are regulated by, dorsal-ventral patterning. <it>AmSoxC, D </it>and <it>F </it>were expressed ubiquitously in late embryos and in the follicle cells of the queen ovary. Expression of <it>AmSoxF </it>and two <it>AmSoxE </it>genes was detected in the drone testis.</p> <p>Conclusion</p> <p>Insect genomes contain between eight and nine <it>Sox </it>genes, with at least four members belonging to <it>Sox </it>group B and other <it>Sox </it>subgroups each being represented by a single <it>Sox </it>gene. Hymenopteran insects have an additional <it>SoxE </it>gene, which may have arisen by gene duplication. Expression analyses of honeybee <it>SoxB </it>genes implies that this group of genes may be able to rapidly evolve new functions and expression domains, while the combined expression pattern of all the <it>SoxB </it>genes is maintained.</p

Germ cell specification and ovary structure in the rotifer Brachionus plicatilis

<p>Abstract</p> <p>Background</p> <p>The segregation of the germline from somatic tissues is an essential process in the development of all animals. Specification of the primordial germ cells (PGCs) takes place via different strategies across animal phyla; either specified early in embryogenesis by the inheritance of maternal determinants in the cytoplasm of the oocyte ('preformation') or selected later in embryonic development from undifferentiated precursors by a localized inductive signal ('epigenesis'). Here we investigate the specification and development of the germ cells in the rotifer <it>Brachionus plicatilis</it>, a member of the poorly-characterized superphyla Lophotrochozoa, by isolating the <it>Brachionus </it>homologues of the conserved germ cell markers <it>vasa </it>and <it>nanos</it>, and examining their expression using <it>in situ </it>hybridization.</p> <p>Results</p> <p><it>Bpvasa </it>and <it>Bpnos </it>RNA expression have very similar distributions in the <it>Brachionus </it>ovary, showing ubiquitous expression in the vitellarium, with higher levels in the putative germ cell cluster. <it>Bpvas </it>RNA expression is present in freshly laid eggs, remaining ubiquitous in embryos until at least the 96 cell stage after which expression narrows to a small cluster of cells at the putative posterior of the embryo, consistent with the developing ovary. <it>Bpnos </it>RNA expression is also present in just-laid eggs but expression is much reduced by the four-cell stage and absent by the 16-cell stage. Shortly before hatching of the juvenile rotifer from the egg, <it>Bpnos </it>RNA expression is re-activated, located in a subset of posterior cells similar to those expressing <it>Bpvas </it>at the same stage.</p> <p>Conclusions</p> <p>The observed expression of <it>vasa </it>and <it>nanos </it>in the developing <it>B. plicatilis </it>embryo implies an epigenetic origin of primordial germ cells in Rotifer.</p

Evolutionary origin and genomic organisation of runt-domain containing genes in arthropods

<p>Abstract</p> <p>Background</p> <p>Gene clusters, such as the <it>Hox </it>gene cluster, are known to have critical roles in development. In eukaryotes gene clusters arise primarily by tandem gene duplication and divergence. Genes within a cluster are often co-regulated, providing selective pressure to maintain the genome organisation, and this co-regulation can result in temporal or spatial co-linearity of gene expression. It has been previously noted that in <it>Drosophila melanogaster</it>, three of the four runt-domain (RD) containing genes are found in a relatively tight cluster on chromosome 1, raising the possibility of a putative functional RD gene cluster in <it>D. melanogaster</it>.</p> <p>Results</p> <p>To investigate the possibility of such a gene cluster, orthologues of the <it>Drosophila melanogaste</it>r RD genes were identified in several endopterygotan insects, two exopterygotan insects and two non-insect arthropods. In all insect species four RD genes were identified and orthology was assigned to the <it>Drosophila </it>sequences by phylogenetic analyses. Although four RD genes were found in the crustacean <it>D. pulex</it>, orthology could not be assigned to the insect sequences, indicating independent gene duplications from a single ancestor following the split of the hexapod lineage from the crustacean lineage.</p> <p>In insects, two chromosomal arrangements of these genes was observed; the first a semi-dispersed cluster, such as in <it>Drosophila</it>, where <it>lozenge </it>is separated from the core cluster of three RD genes often by megabases of DNA. The second arrangement was a tight cluster of the four RD genes, such as in <it>Apis mellifera</it>.</p> <p>This genomic organisation, particularly of the three core RD genes, raises the possibility of shared regulatory elements. <it>In situ </it>hybridisation of embryonic expression of the four RD genes in <it>Drosophila melanogaster </it>and the honeybee <it>A. mellifera </it>shows no evidence for either spatial or temporal co-linearity of expression during embryogenesis.</p> <p>Conclusion</p> <p>All fully sequenced insect genomes contain four RD genes and orthology can be assigned to these genes based on similarity to the <it>D. melanogaster </it>protein sequences. Examination of the genomic organisation of these genes provides evidence for a functional RD gene cluster. RD genes from non-insect arthropods are also clustered, however the lack of orthology between these and insect RD genes suggests this cluster is likely to have resulted from a duplication event independent from that which created the insect RD gene cluster. Analysis of embryonic RD gene expression in two endopterygotan insects, <it>A. mellifera </it>and <it>D. melanogaster</it>, did not show evidence for coordinated gene expression, therefore while the functional significance of this gene cluster remains unknown its maintenance during insect evolution implies some functional significance to the cluster.</p

Isolation and Genetic Characterization of Mother-of-Snow-White, a Maternal Effect Allele Affecting Laterality and Lateralized Behaviors in Zebrafish

In the present work we report evidence compatible with a maternal effect allele affecting left-right development and functional lateralization in vertebrates. Our study demonstrates that the increased frequency of reversed brain asymmetries in a zebrafish line isolated through a behavioral assay is due to selection of mother-of-snow-white (msw), a maternal effect allele involved in early stages of left-right development in zebrafish. msw homozygous females could be identified by screening of their progeny for the position of the parapineal organ because in about 50% of their offspring we found an altered, either bilateral or right-sided, expression of lefty1 and spaw. Deeper investigations at earlier stages of development revealed that msw is involved in the specification and differentiation of precursors of the Kupffer's vesicle, a structure homologous to the mammalian node. To test the hypothesis that msw, by controlling Kupffer's vesicle morphogenesis, controls lateralized behaviors related to diencephalic asymmetries, we analyzed left- and right-parapineal offspring in a “viewing test”. As a result, left- and right-parapineal individuals showed opposite and complementary eye preference when scrutinizing a model predator, and a different degree of lateralization when scrutinizing a virtual companion. As maternal effect genes are expected to evolve more rapidly when compared to zygotic ones, our results highlight the driving force of maternal effect alleles in the evolution of vertebrates behaviors

What Do Studies of Insect Polyphenisms Tell Us about Nutritionally-Triggered Epigenomic Changes and Their Consequences?

Many insects are capable of remarkable changes in biology and form in response to their environment or diet. The most extreme example of these are polyphenisms, which are when two or more different phenotypes are produced from a single genotype in response to the environment. Polyphenisms provide a fascinating opportunity to study how the environment affects an animal’s genome, and how this produces changes in form. Here we review the current state of knowledge of the molecular basis of polyphenisms and what can be learnt from them to understand how nutrition may influence our own genomes