title: Grazing protozoa and magnetosome dissolution in magnetotactic bacteria.
abstract: Magnetotactic bacteria show an ability to navigate along magnetic field lines because of magnetic particles called magnetosomes. All magnetotactic bacteria are unicellular except for the multicellular prokaryote (recently named 'Candidatus Magnetoglobus multicellularis'), which is formed by an orderly assemblage of 17-40 prokaryotic cells that swim as a unit. A ciliate was used in grazing experiments with the M. multicellularis to study the fate of the magnetosomes after ingestion by the protozoa. Ciliates ingested M. multicellularis, which were located in acid vacuoles as demonstrated by confocal laser scanning microscopy. Transmission electron microscopy and X-ray microanalysis of thin-sectioned ciliates showed the presence of M. multicellularis and magnetosomes inside vacuoles in different degrees of degradation. The magnetosomes are dissolved within the acidic vacuoles of the ciliate. Depending on the rate of M. multicellularis consumption by the ciliates the iron from the magnetosomes may be recycled to the environment in a more soluble form.
authors.affiliation: Departamento de Microbiologia Geral, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil.
authors.forename: Juliana L
authors.initials: JL
authors.lastname: Martins
authors.forename: Thaís S
authors.initials: TS
authors.lastname: Silveira
authors.forename: Fernanda
authors.initials: F
authors.lastname: Abreu
authors.forename: Karen T
authors.initials: KT
authors.lastname: Silva
authors.forename: Inácio D
authors.initials: ID
authors.lastname: da Silva-Neto
authors.forename: Ulysses
authors.initials: U
authors.lastname: Lins
mesh_terms: D000818:Animals; D002465:Cell Movement / Q000502:physiology*; D016798:Ciliophora / Q000378:metabolism / Q000648:ultrastructure; D016812:Euplotes / Q000378:metabolism / Q000648:ultrastructure; D002479:Inclusion Bodies / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D008280:Magnetics; D011235:Predatory Behavior / Q000502:physiology
chemical_list: D007501:Iron