Methods in the general biology and genetics of paramecium aurelia

Sonneborn, T. M.

doi:10.1002/jez.1401130106

Cited by 507 publications

(149 citation statements)

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“…Serum P, no. 113, was made by injecting 5 x 106 homogenized protozoa of stock 3, serotype G, according to the method of Sonneborn (1950). This was used for immobilization tests.…”

Section: Methodsmentioning

confidence: 99%

“…Paramecia were filtered through sixteen layers of cheesecloth and concentrated by passing through a Massey-Harris automatic cream separator, modified as described by Preer & Preer (1959). A population count was carried out according to the method described by Sonneborn (1950). Further concentration was achieved by centrifuging for 2 min.…”

Section: Methodsmentioning

confidence: 99%

“…Cultures of stock 28, serotype G, were grown at 12" in 2 1. Erlenmeyer flasks and fed enough to allow no more than one fission every 10 days (Sonneborn, 1950), on the average. When a population of suitable size had been reached, the organisms were supplied with enough food to undergo one fission/day and transferred to 31" for transformation to proceed.…”

mentioning

confidence: 99%

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Gel Diffusion Studies on Serotype and Serotype Transformation in Paramecium

Balbinder

Jiao

1959

Journal of General Microbiology

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SUMMARY: Antigens G and E of stock 28 variety 2 of Paramecium aurelia show cross-reactions with their respective antisera in immobilization and gel diffusion tests. In immobilization tests the anti-E serum P, no. 132, shows the strongest cross-reaction; in gel diffusion tests the anti-G serum P, no. 130, cross reacts more strongly. During serotype transformation of type G protozoa to type E, the increase of the E antigen and the disappearance of the G antigen were followed by the gel diffusion technique. However, because of the peculiar cross-reactions of these two antigens, only the increase of the new (E) antigen was studied quantitatively by this technique. No reliable measurements of the loss of the old (G) antigen were obtained. The results indicate that during transformation the amount of the new antigen increased exponentially.Within a given stock of Paramecium azcrelia a number of clones representing different antigenic types or serotypes may be obtained. Each clone is immobilized by an appropriate dilution of homologous antiserum made against protozoa of its own serotype and unaffected by similar dilutions of sera made against other serotypes. Studies of the immobilization antigens of Paramecium by Sonneborn and others have revealed that they are determined by a complex interaction of three factors: the environment, a system of cytoplasmic inheritance, and nuclear genes (review; see Beale, 1957). Changes in the environment often induce a transformation from one serotype to another. Often the different serotypes of a stock are stable under the same environmental conditions. Under such circumstances crosses between the different serotypes reveal that the differences are maintained by a system of cytoplasmic inheritance. The serotypes which can be manifested, their specific properties and also their stability have been shown to vary from stock to stock, and to be under the control of nuclear genes.The data are consistent with the idea that there is a separate primary genic locus for each serotype, a locus which influences whether the serotype in Paramecium aurelia can be expressed, its stability, and its immunological specificity. More than one locus, however, may be involved in stability. Normally, the effect of only one primary locus is evidenced a t any one time, i.e. only one antigen is detectable. In most of the cases studied any one of a number of equally competent loci may come to expression under a particular set of conditions. Once a type is expressed, however, the continued expression of that locus rather than the others is transmitted hereditarily through the Spring Harbor,

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“…Serum P, no. 113, was made by injecting 5 x 106 homogenized protozoa of stock 3, serotype G, according to the method of Sonneborn (1950). This was used for immobilization tests.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Gel Diffusion Studies on Serotype and Serotype Transformation in Paramecium

Balbinder

Jiao

1959

Journal of General Microbiology

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“…It is well known that aged cells undergo autogamy in the presence of excess food, violating the usual rule that cells must be starved to undergo autogamy (38,40). The detection of aged cells with no food vacuoles in the presence of excess food would explain the ability of aged cells to undergo the process; the aged cells are starving despite the presence of excess food.…”

Section: Smith-sonneborn and Rodermel Organelles And Agingmentioning

confidence: 99%

Loss of endocytic capacity in aging Paramecium. The importance of cytoplasmic organelles.

Smith-Sonneborn¹,

Rodermel²

1976

The Journal of Cell Biology

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Aged cells have significantly fewer food vacuoles and ingest fewer bacteria than young cells. Loss of food vacuoles was explained by a decreasing difference in the food vacuole formation and excretion rates; the formation rate declined more rapidly than the excretion rate, approaching equivalence at 160 fissions, when the proportion of cells with no food vacuoles, in the presence of excess food, abruptly increased. A model for cellular aging is presented in which control of organelle numbers and cyclical interactions between the nucleus and cytoplasm may be of critical importance.

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“…Daily isolations of single cells into fresh media were carried out and after a large number of fissions had ensued (approx. 150) cells were examined to see if they underwent autogamy (Sonneborn, 1950). After this number of fissions autogamy occurred as seen by macronuclear breakdown.…”

Section: Crossesmentioning

confidence: 99%