The Biological Effects of X-Rays on Mating Types and Conjugation of Paramecium Bursaria

Wichterman, Ralph

doi:10.2307/1538349

Cited by 21 publications

(9 citation statements)

References 16 publications

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“…of the concentrated suspensions or homogenates were added to plastic containers (7/8 x 7/8 x 11/16 inches) which were then packed in ice in plastic Petri dishes to be irradiated or used as controls. The radiation factors have been described (Wichterman, 1948). The radiation flux was 6300 r per minute.…”

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confidence: 99%

The Effect of X-Irradiation on Nuclease Activity and Respiration of Tetrahymena Geleii W

Eichel

Roth

1953

The Biological Bulletin

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confidence: 99%

The Effect of X-Irradiation on Nuclease Activity and Respiration of Tetrahymena Geleii W

Eichel

Roth

1953

The Biological Bulletin

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“…Several investigators have reported that the algae can be * Correspondence and reprints: Department of Biological Science, Faculty of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan. **Present adress: Laboratory of Biology, Faculty of Domestic Science, Nishi-Kyushu University, Kanzaki, Japan removed by culturing P. bursaria in continuous darkness (Jennings 1938, Siegel 1960, Karakashian 1963, Pado 1965, by X-ray irradiation (Wichterman 1948), or by exposure to a photosynthesis inhibitor such as 3-(3,4-dichlorophenyl)-1,1-dimetbyl urea (DCMU) (Reisser 1976). Unfortunately, in these experiments, defined experimental conditions including the growth phase of treated ciliates have not been described.…”

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confidence: 99%

Cloning and characterization of endosymbiotic algae isolated from Paramecium bursaria

et al. 1998

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Summary.The green paramecium Paramecium bursaria has many endosymbiotic algae in its cytoplasm. Here, we cloned and characterized endosymbiotic algae from P. bursaria and examined in detail the interaction between the cloned algae and algae-free paramecia. Homogenates of P. bursaria were cultured on agar plates containing various kinds of media to establish clones of the endosymbiotic algae. Many algal colonies were obtained from poorly nutritious medium (CA medium) after one month in culture. Algae were picked up from these colonies and inoculations were repeated 9 times on agar plates containing CA medium. On enriched media including bacto-peptone, glucose, proteose-peptone and/or yeast extract, however, bacteria and mold grew rapidly and no algal colonies were formed. When tile cloned algae were cultured in liquid CA medium, they grew faster than on agar plates and the numbers stayed constant at 1 • 107 algae/ml after 7 day s in culture. They revealed high infectivity to algae-free paramecia, and an incubation period of 24 h and at least 1 • 103 algae/paramecium were required to achieve successful infection (80-90%). The growth and infection rate did not change through 74 repeated inoculations of algae in liquid CA medium. Optical microscopic observations revealed marked morphological similarity between endosymbiotic algae and free-living Chlorella, but the latter showed no infectivity to algae-free paramecia. The cloned endosymbiotic algae presented here will provide an excellent opportunity to examine the mechanism of symbiont-host interaction.

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“…Although this symbiosis is stable, the symbionts can be artificially separated and cultured independently (Wichterman 1948; Siegel 1960; Reisser 1976; Hosoya et al 1995; Nishihara et al 1998). Aposymbiotic cells of P. bursaria can be cultured, but they show a lower growth rate than symbiotic cells under poor nutrient conditions (Weis 1974).…”

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Genetics of the relationship between the ciliate Paramecium bursaria and its symbiotic algae

Tonooka

Watanabe

2007

Invertebrate Biology

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Paramecium bursaria, a freshwater protozoan, typically harbors hundreds of symbiotic algae (Chlorella sp.) in its cytoplasm. The relationship between host paramecia and symbiotic algae is stable and mutually beneficial in natural environments. We recently collected an aposymbiotic strain of P. bursaria. Infection experiments revealed that the natural aposymbiotic strain (Ysa2) showed unstable symbiosis with Chlorella sp. The algae aggregated at the posterior region of the host, resulting in aposymbiotic cell production after cell division. Cross-breeding analyses were performed to determine the heritability of the aposymbiotic condition. In crosses of Ysa2 with symbiotic strains of P. bursaria, F1 progeny were able to form stable symbioses with Chlorella sp. However, unstable symbiosis, resembling Ysa2 infection, occurred in some F2 progeny of sibling crosses between symbiotic F1 clones. Infection experiments using aposymbiotic F2 cells showed that these F2 subclones have limited ability to reestablish the symbiosis. These results indicate that the maintenance of stable symbiosis is genetically controlled and heritable, and that Ysa2 is a mutant lacking the mechanisms to establish stable symbiosis with Chlorella sp.

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The Biological Effects of X-Rays on Mating Types and Conjugation of Paramecium Bursaria

Cited by 21 publications

References 16 publications

The Effect of X-Irradiation on Nuclease Activity and Respiration of Tetrahymena Geleii W

The Effect of X-Irradiation on Nuclease Activity and Respiration of Tetrahymena Geleii W

Cloning and characterization of endosymbiotic algae isolated from Paramecium bursaria

Genetics of the relationship between the ciliate Paramecium bursaria and its symbiotic algae

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