title: Elemental characterization of microorganism granules by EFTEM in the tube wall of a deep-sea vent invertebrate.
abstract: Microorganisms colonizing the exoskeletons of the tube worm Riftia pachyptila are described at the ultrastructural level. The prokaryotic cells from the worm tube wall differ from those colonizing the exoskeleton outer surface in the presence of an electron dense granule. The morphology and distribution of these bacteria-like cells are described. Prokaryotic organisms are assembled in nodules which increased in size in the oldest part of the exoskeleton. The aspect, location and elemental composition of the intracellular granules are determined. Most of them (100 nm in diameter) are located close to the cell membrane and exhibit a homogeneous and amorphous content. EDX and EFTEM microanalyses show that these structures contain phosphorus, oxygen and iron. All together these data suggest that these granules are iron polyphosphates. These structures may act as energy sources for making ATP during anoxic conditions as existing in hydrothermal environments.
authors.affiliation: Equipe Adaptations aux Milieux Extrêmes, UMR 7622 CNRS, Université Pierre et Marie Curie, Bâtiment A, 7, quai St-Bernard, 75252 Paris cedex 5, France. jean-pierre.lechaire@snv.jussieu.fr
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Lechaire
authors.forename: Bruce
authors.initials: B
authors.lastname: Shillito
authors.forename: Ghislaine
authors.initials: G
authors.lastname: Frébourg
authors.forename: Françoise
authors.initials: F
authors.lastname: Gaill
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001105:Archaea / Q000378:metabolism / Q000648:ultrastructure*; D001674:Bioelectric Energy Sources / Q000382:microbiology; D003594:Cytoplasmic Granules / Q000378:metabolism / Q000648:ultrastructure*; D004602:Elements; D004734:Energy Metabolism / Q000502:physiology; D007448:Invertebrates / Q000382:microbiology*; D058085:Iron Compounds / Q000378:metabolism; D008854:Microscopy, Electron; D011122:Polyphosphates / Q000378:metabolism; D011387:Prokaryotic Cells / Q000378:metabolism / Q000648:ultrastructure*; D013559:Symbiosis / Q000502:physiology
chemical_list: D004602:Elements; D058085:Iron Compounds; D011122:Polyphosphates; D000255:Adenosine Triphosphate