The Paramecium aurelia Complex of Fourteen Sibling Species

Sonneborn, T. M.

doi:10.2307/3224977

Cited by 387 publications

(251 citation statements)

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“…Stocks and cell culturing P. tetraurelia, nd6/nd6 with 51S background (Lefort-Tran et al, 1981) and wild-type strain 7S (Sonneborn, 1975), was cultured at 22 8C in a growth medium of buffered wheat-grass extract inoculated with Enterobacter aerogenes (Sonneborn, 1970). Single cells were isolated and grown for more than twenty fissions before each clone was starved to induce autogamy (Berger, 1986).…”

Section: Methodsmentioning

confidence: 99%

Expression of the green fluorescent protein in Paramecium tetraurelia

Hauser

Haynes

Kung

et al. 2000

European Journal of Cell Biology

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Section: Methodsmentioning

confidence: 99%

Expression of the green fluorescent protein in Paramecium tetraurelia

Hauser

Haynes

Kung

et al. 2000

European Journal of Cell Biology

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“…Depending on the type of surface antigens (SAg) present, cells are assigned to different serotypes [57]. Among SAg there are groups of :s40-45 kDa and 220 to >300 kDa [1, 2, 14.24,43,51,53].…”

Section: Introductionmentioning

confidence: 99%

Immunolabeling analysis of biosynthetic and degradative pathways of cell surface components (glycocalyx) in Paramecium cells

Flötenmeyer

Momayezi

Plattner

1999

European Journal of Cell Biology

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Cell surface -glycocalyx -immuno-labelingParameciumBiosynthetic and degradative pathways of glycocalyx components are largely unknown in Paramecium and in some related parasitic protozoa. We isolated cell surface (glyco-)proteins. i.e .. surface antigens (SAg) and used them in the native (nSAg) or denatured (dSAg) state to produce antibodies (AB) for immunolocalization by confocal imaging and by quantitative immunogold EM-labeling of ultrathin sections or of freeze-fracture replicas. Antibodies against nSAg or dSAg, respectively, yield different labeling densities over individual structures, thus indicating biosynthetic or degradative pathways, respectively. We derive the following biosynthetic way: ER~Golgi apparatus~non-regulated/non-dense core vesicle transport~diffusional spread over non-ciliary (somatic) and ciliary cell membrane. For degradation we show the following pathways: Concentration of nSAg in the cytostome~nascent digestive vacuole~mature vacuolesr elease of dSAg at cytoproct, with partial retrieval by "discoidal vesicles". A second internalization pathway proceeds via coated pits ("parasomal sacs")~early endosomes ("terminal cisternae")d igestive vacuoles. Dense packing of SAg in the glycocalyx may drive them into the endo-/phagocytic pathway. Still more intriguing is the site of nSAg integration into the cell membrane by unstimulated exocytosis. We consider unconspicuous clear vesicles relevant for nSAg export, probably via sites which most of the time are occupied by coated pits. This could compensate for membrane retrieval by coated pits, while scarcity of smooth profiles at these sites may be explained by the much longer time period required for coated pit formatiou as compared to exocytosis.

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“…Some equilibrium must be reached between speciation and extinction rates with minor ecological consequences, so that the effective evolutionary unit is not the species, but the complex itself. Thus the evolutionary significance of the E cmssus complex is very different from that of some other complexes of sibling species, for instance Pardmecium aurelim (Sonneborn, 1975) discovered in this manner: the recessive alleles were present in a pond population. As for a polygenically determined trait the situation may be somewhat different.…”

Section: Morphological Variants and Evolutionmentioning

confidence: 99%