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Simon, Anaele

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Simon, Anaele
Affiliation principale
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https://libra.unine.ch/handle/123456789/30616

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  • Publication
    Accès libre
    Mycamoeba gemmipara nov. gen., nov. sp., the First Cultured Member of the Environmental Dermamoebidae Clade LKM74 and its Unusual Life Cycle
    (2016-8-20)
    Blandenier, Quentin 
    ;
    Seppey, Christophe 
    ;
    Singer, David 
    ;
    Vlimant, Michèle 
    ;
    Simon, Anaele 
    ;
    Duckert, Clément
    ;
    Lara, Enrique 
    Since the first environmental DNA surveys, entire groups of sequences called “environmental clades” did not have any cultured representative. LKM74 is an amoebozoan clade affiliated to Dermamoebidae, whose presence is pervasively reported in soil and freshwater. We obtained an isolate from soil that we assigned to LKM74 by molecular phylogeny, close related to freshwater clones. We described Mycamoeba gemmipara based on observations made with light- and transmission electron microscopy. It is an extremely small amoeba with typical lingulate shape. Unlike other Dermamoebidae, it lacked ornamentation on its cell membrane, and condensed chromatin formed characteristic patterns in the nucleus. M. gemmipara displayed a unique life cycle: trophozoites formed walled coccoid stages which grew through successive buddings and developed into branched structures holding cysts. These structures, measuring hundreds of micrometres, are built as the exclusive product of osmotrophic feeding. In order to demonstrate that M. gemmipara is a genuine soil inhabitant, we screened its presence in an environmental soil DNA diversity survey performed on an experimental setup where pig cadavers were left to decompose in soils in order to follow changes in eukaryotic communities. M. gemmipara was present in all samples, although related reads were uncommon underneath the cadaver.
  • Publication
    Accès libre
    Exploiting the fungal highway: development of a novel tool for the in situ isolation of bacteria migrating along fungal mycelium
    (2015)
    Simon, Anaele 
    ;
    Bindschedler, Saskia 
    ;
    Job, Daniel 
    ;
    Wick, Lukas Y.
    ;
    Filippidou, Sevasti 
    ;
    Kooli, Wafa M.
    ;
    Verrecchia, Eric P.
    ;
    Junier, Pilar 
    Fungi and bacteria form various associations that are central to numerous environmental processes. In the so-called fungal highway, bacteria disperse along fungal mycelium. We developed a novel tool for the in situ isolation of bacteria moving along fungal hyphae as well as for the recovery of fungi potentially involved in dispersal, both of which are attracted towards a target culture medium. We present the validation and the results of the first in situ test. Couples of fungi and bacteria were isolated from soil. Amongst the enriched organisms, we identified several species of fast-growing fungi (Fusarium sp. and Chaetomium sp.), as well as various potentially associated bacterial groups, including Variovorax soli, Olivibacter soli, Acinetobacter calcoaceticus, and several species of the genera Stenotrophomonas, Achromobacter and Ochrobactrum. Migration of bacteria along fungal hyphae across a discontinuous medium was confirmed in most of the cases. Although the majority of the bacteria for which migration was confirmed were also positive for flagellar motility, not all motile bacteria dispersed using their potential fungal partner. In addition, the importance of hydrophobicity of the fungal mycelial surface was confirmed. Future applications of the columns include targeting different types of microorganisms and their interactions, either by enrichment or by state of the art molecular biological methods.
  • Publication
    Accès libre
    Bacterial farming by the fungus Morchella crassipes
    (The Royal Society of London, )
    Pion, Martin
    ;
    Jorge E. Spangenberg
    ;
    Simon, Anaele 
    ;
    Bindschedler, Saskia 
    ;
    Flury, Coralie
    ;
    Chatelain, Auriel
    ;
    Bshary, Redouan 
    ;
    Job, Daniel 
    ;
    Junier, Pilar 
    The interactions between bacteria and fungi, the main actors of the soil microbiome, remain poorly studied. Here, we show that the saprotrophic and ectomycorrhizal soil fungus Morchella crassipes acts as a bacterial farmer of Pseudomonas putida, which serves as a model soil bacterium. Farming by M. crassipes consists of bacterial dispersal, bacterial rearing with fungal exudates, as well as harvesting and translocation of bacterial carbon. The different phases were confirmed experimentally using cell counting and 13C probing. Common criteria met by other non-human farming systems are also valid for M. crassipes farming, including habitual planting, cultivation and harvesting. Specific traits include delocalization of food production and consumption and separation of roles in the colony (source versus sink areas), which are also found in human agriculture. Our study evidences a hitherto unknown mutualistic association in which bacteria gain through dispersal and rearing, while the fungus gains through the harvesting of an additional carbon source and increased stress resistance of the mycelium. This type of interaction between fungi and bacteria may play a key role in soils.