title: Amoeba-resisting bacteria found in multilamellar bodies secreted by Dictyostelium discoideum: social amoebae can also package bacteria.
abstract: Many bacteria can resist phagocytic digestion by various protozoa. Some of these bacteria (all human pathogens) are known to be packaged in multilamellar bodies produced in the phagocytic pathway of the protozoa and that are secreted into the extracellular milieu. Packaged bacteria are protected from harsh conditions, and the packaging process is suspected to promote bacterial persistence in the environment. To date, only a limited number of protozoa, belonging to free-living amoebae and ciliates, have been shown to perform bacteria packaging. It is still unknown if social amoebae can do bacteria packaging. The link between the capacity of 136 bacterial isolates to resist the grazing of the social amoeba Dictyostelium discoideum and to be packaged by this amoeba was investigated in the present study. The 45 bacterial isolates displaying a resisting phenotype were tested for their capacity to be packaged. A total of seven isolates from Cupriavidus, Micrococcus, Microbacterium and Rathayibacter genera seemed to be packaged and secreted by D. discoideum based on immunofluorescence results. Electron microscopy confirmed that the Cupriavidus and Rathayibacter isolates were formally packaged. These results show that social amoebae can package some bacteria from the environment revealing a new aspect of microbial ecology.
authors: Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, Quebec City, QC, G1V 0A6, Canada Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Hôpital Laval, Quebec City, QC, G1V 4G5, Canada.
authors: Valérie E
authors: VE
authors: Paquet
authors: Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, Quebec City, QC, G1V 0A6, Canada Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Hôpital Laval, Quebec City, QC, G1V 4G5, Canada Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Quebec City, QC, G1V 0A6, Canada steve.charette@bcm.ulaval.ca.
authors: Steve J
authors: SJ
authors: Charette
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D004023:Dictyostelium / Q000276:immunology / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny
keywords: Cupriavidus; Dictyostelium discoideum; Rathayibacter; amoeba-resisting bacteria; multilamellar bodies; packaged bacteria