Publications associées à Transformation of the Drosophila Sex-Manipulative Endosymbiont Spiroplasma poulsonii and Persisting Hurdles for Functional Genetic Studies

Photobiology and metabolic interactions in the symbiotic jellyfish Cassiopea

The symbiont-bearing jellyfish Cassiopea live a benthic lifestyle, positioning themselves upside-down on sediments in shallow waters to allow their endosymbiotic algae to photosynthesize in the sunlight. Over the last decades Cassiopea has become increasin ...

EPFL2023

Metabolism of the symbiotic jellyfish Cassiopea in a changing environment

Gaëlle Delphine Toullec

Ocean warming and other anthropogenic impacts have led to a global decline in many photosymbiotic cnidarians, most notably reef-building corals. But some species of the symbiotic and (sub-)tropical upside-down jellyfish Cassiopea are increasingly reported ...

EPFL2023

Symbiotic nutrient exchange enhances the long-term survival of cassiosomes, the autonomous stinging-cell structures of Cassiopea

Cristina Martin Olmos, Anders Meibom, Niclas Heidelberg Lyndby, Gaëlle Delphine Toullec, Nils Rädecker, Claudia Isabella Pogoreutz, Guilhem Maurice Louis Banc-Prandi

Medusae of the widely distributed upside-down jellyfish Cassiopea release autonomous, mobile stinging structures. These so-called cassiosomes play a role in predator defense and prey capture, and are major contributors to “contactless” stinging incidents i ...

2023

Natural competence of the pathogen Acinetobacter baumannii: an elusive phenomenon

Nina Vesel

Natural competence for transformation is an important driver of horizontal DNA exchange between different organisms. This can result in accumulation of dangerous genetic features, such as antibiotic resistance genes, in a single organism. One example of an ...

EPFL2022

Presence of algal symbionts affects denitrifying bacterial communities in the sea anemone Aiptasia coral model

Anders Meibom, Nils Rädecker, Claudia Isabella Pogoreutz

The coral-algal symbiosis is maintained by a constant and limited nitrogen availability in the holobiont. Denitrifiers, i.e., prokaryotes reducing nitrate/nitrite to dinitrogen, could contribute to maintaining the nitrogen limitation in the coral holobiont ...

2022

Intrinsically High Capacity of Animal Cells From a Symbiotic Cnidarian to Deal With Pro-Oxidative Conditions

Gaëlle Delphine Toullec

The cnidarian-dinoflagellate symbiosis is a mutualistic intracellular association based on the photosynthetic activity of the endosymbiont. This relationship involves significant constraints and requires co-evolution processes, such as an extensive capacit ...

FRONTIERS MEDIA SA2022

Contrasting Microbiome Dynamics of Putative Denitrifying Bacteria in Two Octocoral Species Exposed to Dissolved Organic Carbon (DOC) and Warming

Nils Rädecker, Claudia Isabella Pogoreutz

Mutualistic nutrient cycling in the coral-algae symbiosis depends on limited nitrogen (N) availability for algal symbionts. Denitrifying prokaryotes capable of reducing nitrate or nitrite to dinitrogen could thus support coral holobiont functioning by limi ...

2022

Rapid molecular evolution of Spiroplasma symbionts of Drosophila

Bruno Lemaitre, Florent François Masson

Spiroplasma is a genus of Mollicutes whose members include plant pathogens, insect pathogens and endosymbionts of animals. Spiroplasma phenotypes have been repeatedly observed to be spontaneously lost in Drosophila cultures, and several studies have docume ...

2021

Dual proteomics of Drosophila melanogaster hemolymph infected with the heritable endosymbiont Spiroplasma poulsonii

Bruno Lemaitre, Fanny Schüpfer, Samuel Rommelaere, Florent François Masson, Alice Marra

Insects are frequently infected with heritable bacterial endosymbionts. Endosymbionts have a dramatic impact on their host physiology and evolution. Their tissue distribution is variable with some species being housed intracellularly, some extracellularly ...

2021

The role of immune effectors in controlling Drosophila-microbes interactions

Alice Marra

All live beings are in constant interaction with microorganisms that may be beneficial, deleterious or commensal. Insects in particular live in close contact with microorganisms. This is especially true for species, like the fruit fly Drosophila melanogast ...

EPFL2021

Heat stress destabilizes symbiotic nutrient cycling in corals

Anders Meibom, Nils Rädecker, Claudia Isabella Pogoreutz

Recurrent mass bleaching events are pushing coral reefs worldwide to the brink of ecological collapse. While the symptoms and consequences of this breakdown of the coral–algal symbiosis have been extensively characterized, our understanding of the underlyi ...

2021

Sub-cellular imaging shows reduced photosynthetic carbon and increased nitrogen assimilation by the non-native endosymbiontDurusdinium trenchiiin the model cnidarian Aiptasia

Anders Meibom

Hosting different symbiont species can affect inter-partner nutritional fluxes within the cnidarian-dinoflagellate symbiosis. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we measured the spatial incorporation of photosynthetically fixed(13)C ...

WILEY2020

Tracking the cargo of extracellular symbionts into host tissues with correlated electron microscopy and nanoscale secondary ion mass spectrometry imaging

Anders Meibom, Stéphane Laurent Escrig, Stéphanie Kéren Cohen

Extracellular bacterial symbionts communicate biochemically with their hosts to establish niches that foster the partnership. Using quantitative ion microprobe isotopic imaging (nanoscale secondary ion mass spectrometry [NanoSIMS]), we surveyed localizatio ...

WILEY2020

Growing Ungrowable Bacteria: Overview and Perspectives on Insect Symbiont Culturability

Bruno Lemaitre, Florent François Masson

Insects are often involved in endosymbiosis, that is, the housing of symbiotic microbes within their tissues or within their cells. Endosymbionts are a major driving force in insects' evolution, because they dramatically affect their host physiology and al ...

AMER SOC MICROBIOLOGY2020

Blind killing of both male and female Drosophila embryos by a natural variant of the endosymbiotic bacterium Spiroplasma poulsonii

Bruno Lemaitre, Juan Camilo Paredes Escobar, Mario Gonzalo Garcia Arraez, Samuel Rommelaere, Florent François Masson

Spiroplasma poulsonii is a vertically transmitted endosymbiont of Drosophila melanogaster that causes male-killing, that is the death of infected male embryos during embryogenesis. Here, we report a natural variant of S. poulsonii that is efficiently verti ...

WILEY2020

Intracellular competition for nitrogen controls dinoflagellate population density in corals

Julia Marie Jeanne Yvonne Bodin, Anders Meibom, Stéphane Laurent Escrig, Maria-Evangelia Giovani, Thomas Krüger, Maoz Fine

The density of dinoflagellate microalgae in the tissue of symbiotic corals is an important determinant for health and productivity of the coral animal. Yet, the specific mechanism for their regulation and the consequence for coral nutrition are insufficien ...

ROYAL SOC2020

Role of Nimrod receptors in the Drosophila melanogaster cellular immune response

Claudia Melcarne

The use of modern molecular biology tools and simple but powerful tractable model organisms such as Drosophila has contributed significantly to our recent advances in the innate immunity field, notably phagocytosis. Since 2001, many phagocytic transmembran ...

EPFL2020

Commensal Gut Bacteria Buffer the Impact of Host Genetic Variants on Drosophila Developmental Traits under Nutritional Stress

Michael Vincent Frochaux, Bart Deplancke, Maroun Bou Sleiman, Virginie Sandra Braman, Maria Litovchenko

Eukaryotic genomes encode several buffering mechanisms that robustly maintain invariant phenotypic outcome despite fluctuating environmental conditions. Here we show that the Drosophila gut-associated commensals, represented by a single facultative symbion ...

2019

Weevil pgrp-lb prevents endosymbiont TCT dissemination and chronic host systemic immune activation

Florent François Masson, João Pedro Alves Da Silva

Long-term intracellular symbiosis (or endosymbiosis) is widely distributed across invertebrates and is recognized as a major driving force in evolution. However, the maintenance of immune homeostasis in organisms chronically infected with mutualistic bacte ...

National Academy of Sciences2019

Functional analysis of RIP toxins from the Drosophila endosymbiont Spiroplasma poulsonii

Bruno Lemaitre, Juan Camilo Paredes Escobar, Mario Gonzalo Garcia Arraez, Florent François Masson

BackgroundInsects frequently live in close relationship with symbiotic bacteria that carry out beneficial functions for their host, like protection against parasites and viruses. However, in some cases, the mutualistic nature of such associations is put in ...

2019