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THE ACTION OF X-RAYS ON EUPLOTES TAYLORI AND ASSOCIATED BACTERIA
M G Brown1, J M Luck, G Sheets
1Laboratory for Chemophysical Biology, Stanford University, Stanford University.
The Journal of General Physiology
|October 30, 2009
Summary
X-ray irradiation can sterilize protozoa like Euplotes taylori by killing associated bacteria more effectively. This method also temporarily halts ciliary activity in protozoa without creating toxic byproducts.
Area of Science:
- Microbiology
- Protozoology
- Radiation Biology
Background:
- Protozoa and bacteria often coexist in biological samples.
- Sterilization methods are crucial for isolating and studying microorganisms.
- Differential radiation resistance between protozoa and bacteria is not well-established.
Purpose of the Study:
- To determine the minimum lethal dose of x-rays for Euplotes taylori.
- To assess the effect of x-ray irradiation on the ciliary activity of Euplotes taylori.
- To compare the radiosensitivity of Euplotes taylori with common bacterial species.
Main Methods:
- Determining the minimum lethal dose of x-rays for Euplotes taylori.
- Irradiating Euplotes taylori and observing ciliary activity.
- Irradiating pure cultures of Pseudomonas fluorescens and Bacillus coli, K(13).
- Testing irradiated media for toxicity.
- Assessing the nutritional value of irradiated bacteria for Euplotes.
Main Results:
- A 220-second x-ray exposure (464,200 Roentgen units) was the minimum lethal dose for Euplotes taylori.
- Irradiation of Euplotes taylori for 100-220 seconds caused temporary cessation of ciliary activity.
- Pseudomonas fluorescens and Bacillus coli, K(13) were killed by significantly shorter exposures (15 and 45 seconds, respectively).
- Irradiated media were not toxic, and irradiated bacteria were unsuitable for Euplotes nutrition.
Conclusions:
- X-ray irradiation offers a method for the comparative sterilization of protozoa, targeting associated bacteria.
- Differential radiosensitivity allows for selective elimination of bacteria without immediate harm to protozoa.
- Temporary ciliary dysfunction in protozoa is a dose-dependent effect of x-ray exposure.
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