Search results for "METAMORPHOSIS"
showing 10 items of 93 documents
DNA Methylation and Potential for Epigenetic Regulation in Pygospio elegans.
2015
Transitions in developmental mode are common evolutionarily, but how and why they occur is not understood. Developmental mode describes larval phenotypes, including morphology, ecology and behavior of larvae, which typically are generalized across different species. The polychaete worm Pygospio elegans is one of few species polymorphic in developmental mode, with multiple larval phenotypes, providing a possibility to examine the potential mechanisms allowing transitions in developmental mode. We investigated the presence of DNA methylation in P. elegans, and, since maternal provisioning is a key factor determining eventual larval phenotype, we compared patterns of DNA methylation in females…
A novel intracellular mutualistic bacterium in the invasive ant Cardiocondyla obscurior.
2016
The evolution of eukaryotic organisms is often strongly influenced by microbial symbionts that confer novel traits to their hosts. Here we describe the intracellular Enterobacteriaceae symbiont of the invasive ant Cardiocondyla obscurior, 'Candidatus Westeberhardia cardiocondylae'. Upon metamorphosis, Westeberhardia is found in gut-associated bacteriomes that deteriorate following eclosion. Only queens maintain Westeberhardia in the ovarian nurse cells from where the symbionts are transmitted to late-stage oocytes during nurse cell depletion. Functional analyses of the streamlined genome of Westeberhardia (533 kb, 23.41% GC content) indicate that neither vitamins nor essential amino acids a…
Transcriptional Differences between Diapausing and Non-Diapausing D. montana Females Reared under the Same Photoperiod and Temperature
2016
Background A wide range of insects living at higher latitudes enter diapause at the end of the warm season, which increases their chances of survival through harsh winter conditions. In this study we used RNA sequencing to identify genes involved in adult reproductive diapause in a northern fly species, Drosophila montana. Both diapausing and non-diapausing flies were reared under a critical day length and temperature, where about half of the emerging females enter diapause enabling us to eliminate the effects of varying environmental conditions on gene expression patterns of the two types of female flies. Results RNA sequencing revealed large differences between gene expression patterns of…
Differential localization of voltage-gated potassium channels duringDrosophilametamorphosis
2020
Neuronal excitability is determined by the combination of different ion channels and their sub-neuronal localization. This study utilizes protein trap fly strains with endogenously tagged channels ...
Drosophila Food-Associated Pheromones: Effect of Experience, Genotype and Antibiotics on Larval Behavior
2016
International audience; Animals ubiquitously use chemical signals to communicate many aspects of their social life. These chemical signals often consist of environmental cues mixed with species-specific signals-pheromones-emitted by conspecifics. During their life, insects can use pheromones to aggregate, disperse, choose a mate, or find the most suitable food source on which to lay eggs. Before pupariation, larvae of several Drosophila species migrate to food sources depending on their composition and the presence of pheromones. Some pheromones derive from microbiota gut activity and these food-associated cues can enhance larval attraction or repulsion. To explore the mechanisms underlying…
Olfactory attraction of the hornet Vespa velutina to honeybee colony odors and pheromones.
2014
19 pages; International audience; Since the beginning of the last century, the number of biological invasions has continuously increased worldwide. Due to their environmental and economical consequences, invasive species are now a major concern. Social wasps are particularly efficient invaders because of their distinctive biology and behavior. Among them, the yellow-legged hornet, Vespa velutina, is a keen hunter of domestic honeybees. Its recent introduction to Europe may induce important beekeeping, pollination, and biodiversity problems. Hornets use olfactory cues for the long-range detection of food sources, in this case the location of honeybee colonies, but the exact nature of these c…
Evolution Within a Bizarre Phylum: Homologies of the First Echinoderms
1998
SYNOPSIS. The Extraxial/Axial Theory (EAT) of echinoderm skeletal homologies describes two major body wall types: axial and extraxial. The latter is subdivided into perforate and imperforate regions. Each of the regions has a distinctly different source in early larval development. Axial skeleton originates in the rudiment, and develops in association with the pentaradially arranged hydrocoel according to specific ontogenetic principles. Perforate and imperforate extraxial regions are associated with the left and right somatocoels respectively, are not governed by ontogenetic principles of plate addition, and are products of the non-rudiment part of the larval body. The morphology of even t…
Apoptosis: focus on sea urchin development
2009
It has been proposed that the apoptosis is an essential requirement for the evolution of all animals, in fact the apoptotic program is highly conserved from nematodes to mammals. Throughout development, apoptosis is employed by multicellular organisms to eliminate damaged or unnecessary cells. Here, we will discuss both developmental programmed cell death (PCD) under normal conditions and stress induced apoptosis, in sea urchin embryos. Sea urchin represent an excellent model system for studying embryogenesis and cellular processes involved in metamorphosis. PCD plays an essential role in sculpting and remodelling the embryos and larvae undergoing metamorphosis. Moreover, this marine organi…
Il corpo come opera plastica: Catherine Malabou e le metamorfosi del corporeo
2019
Performance art (like Orlan’s “Carnal Art”) involves artist body in the performance itself and it is based on a clear phenomenological assumption: we “do not have” a body, but we “are” our body, we are our “sculpture”. Fascinated by the enigmas of change, Aesthetics has sought to address the metaphysical question concerning metamorphosis and the problem of identity persistence in change; the solution has been found for centuries in the opposition between essence and appearance: as highlighted by fantastic literature (Ovid, Apuleius, Kafka), in metamorphosis the “substance” remains unchanged and only appearance (or accident) changes. However, the reflection carried out by Catherine Malabou o…
Adhesive papillae ofAscidia malacaswimming larvae: investigations on their sensory function
1999
Summary Swimming larvae of Ascidia malaca bear, in the anterior region of cephalenteron, three adhesive papillae through which they can attach to a substratum prior to metamorphosis. The ultrastructural investigations described in the present work have mainly revealed the presence of three cell types constituting the papillae: (a) collocytes, (b) axial columnar cells, (c) sensory cells. Collocytes, whose ultrastructure is typical of secretory cells, form the adhesive secretion. The ultrastructural observations of the axial columnar cells are insufficient to explain their function. Probably this cell type plays a supporting role though some sensory function cannot be excluded due to the pres…