TABLE 3.

History of the research on the endosymbionts of free-living amoebae and other amoeba-resistant microorganismsa

YrHypothesis or discoveryMicroorganisms(s)Author(s)
1856Presence of slender thread in Paramecium caudatumParamecium caudatumMüller et al.
1879Concept of symbiosisLichenDe Bary
1954Lysis of a free-living amoeba due to bacterial infectionFree-living amoeba and bacteriaDrozanski et al.
1975Presence of an endosymbiont within AcanthamoebaAcanthamoeba and bacteriaProca-Ciobanu et al.
1978Role of free-living amoeba as a reservoir of pathogenic facultative intracellular bacteriaAcanthamoeba and mycobacteriaKrishnan-Prasad et al.
1979Cryptococcus neoformans may survive within AcanthamoebaAcanthamoeba and C. neoformansBunting
1980Role of free-living amoebae in transmission (expelled vesicles)Acanthamoeba and LegionellaRowbotham
1981Increased viability of enteroviruses adsorbed on Acanthamoeba: carrier roleAcanthamoeba and enterovirusesDanes et al.
1986Role of free-living amoebae in the selection of virulence traits (motility)Acanthamoba and LegionellaRowbotham
1988Protection of internalized bacteria from chlorinationEnterobacteriaceae and TetrahymenaKing et al.
1992Role of free-living amoeba in the susceptibility of the internalized bacteria to biocidesAcanthamoba and LegionellaBarker et al.
1995Role of free-living amoeba on the antibiotic susceptibility of the internalized bacteriaAcanthamoba and LegionellaBarker et al.
1996Role of free-living amoeba in the adaptation of the internalized bacteria to life within human macrophagesAcanthamoba and LegionellaBozue et al.
1997Environmental endosymbionts of free-living amoebae as emerging human pathogensParachlamydia acanthamoebaeBirtles et al.
1998Horizontal transfer of clusters of genes contributing to symbiotic life: “symbiosis island”Mesorhizobium lotiSullivan
1998Mitochondria originated by endosymbiosis: relationship between genomes of Rickettsia prowazekii and mitochondriaRickettsia prowazekiiAndersson et al.
2000First genome of a symbiont (of aphids)Buchnera aphidicolaTamas et al.
2003Discovery of mimivirus, a giant virus naturally infecting free-living amoebaeAcanthamoba and mimivirusLa Scola et al.
  • a During the last 5 years, the increased availability of molecular tools and data has led to a better understanding of the relationships between free-living amoebae and amoeba-resistant microorganisms.