Studies on Protozoa, IV: Lethal Effects of the X-Radiation of a Sterile Culture Medium for Colpidium campylum

Taylor, C. V.; Thomas, Jolly; Brown, Morden G.

doi:10.1086/physzool.6.4.30151202

Cited by 26 publications

(11 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Taylor, Thomas, and Brown (1933) employing the same apparatus as in our studies found that Eup/o~s died in 15 minutes after a dosage of 450,000 r. Back and Halberstaedter (1945) found the lethal dosage for paramecium to be of the order of 700,000 r and Halberstaedter and Back (1942) found that between 300,000 and 600,000 r was lethal to Pc~r~dorina. If the correction for absorption is made to our data, the order of magnitude is similar to that found by other investigators.…”

Section: Expe~ntalsupporting

confidence: 65%

“…If the correction for absorption is made to our data, the order of magnitude is similar to that found by other investigators. Taylor, Thomas, and Brown (1933) found that when sterile medium alone is irradiated and the protozoa are added to it, death may occur. They conclude that death is due to development in the medium of toxic substances among the chief of which is probably hydrogen peroxide.…”

Section: Expe~ntalmentioning

confidence: 99%

“…The x-ray equipment used was designed by Dr. Harry Clark for the specific purpose of delivering high intensities of soft radiations; the apparatus has been described before (Taylor, Thomas, and Brown, 1933;Brown, 1933). In the present study it was run at 20,000 volts and 30 milliamperes and a silver target was used.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Sensitization to Heat by X-Rays

Giese

Heath

1948

Journal of General Physiology

View full text Add to dashboard Cite

1. Paramecium caudatum is sensitized to heat by sublethal dosages of x-rays. Thus if paramecia are irradiated, then exposed to a sublethal dosage of heat they are killed, but if the same heat exposure precedes the same dosage of radiations, they are not. 2. Sensitivity to both heat and x-rays is much greater in paramecia from the log growth phase than in those from the stationary phase of a culture. 3. Recovery from heat sensitization in animals from the stationary phase of a culture is slow, requiring several days. 4. Division is readily retarded and even temporarily inhibited by sublethal dosage of x-rays. Recovery of the division rate is fairly slow requiring several days. 5. Paramecia can be killed by a dosage of 1,200,000 r (of which about one-half reach the animal) units of x-radiation alone. Smaller dosages are not lethal if the paramecia are transferred to fresh medium immediately upon completion of irradiation. 6. The possibility of utilization of heat sensitization in treatment of malignant growths is discussed.

show abstract

Section: Expe~ntalsupporting

confidence: 65%

Section: Expe~ntalmentioning

confidence: 99%

See 1 more Smart Citation

Sensitization to Heat by X-Rays

Giese

Heath

1948

Journal of General Physiology

View full text Add to dashboard Cite

show abstract

“…The irradiation of the suspension medium was also found to reduce the survival time (7), delay the cleavage (7), and inhibit the respiration (8) of sea urchin spermatozoa, and to increase the mutation rate (9) and inhibit the growth (10) of bacteria. In some cases, H~O2 was demonstrated in the irradiated medium in concentrations sufficient to account for the observed toxicity (6,7). When this was not found to be the case, the formation of organic peroxides was postulated (8,9).…”

Section: E:]ect Of X-irradiated Salinementioning

confidence: 99%

The Relationship of Hydrogen Peroxide to the Inhibition of the Glyoxalase Activity of Intact Erythrocytes by X-Radiation

Klebanoff

1958

The Journal of General Physiology

View full text Add to dashboard Cite

The x-irradiation of a dilute suspension of erythrocytes results in a decrease in the glyoxalase activity of the cells as a result of a fall in the reduced glutathione level. The present paper deals with the possible role of H~O2 in this reaction.The addition of intact erythrocytes to physiological saline previously irradiated with 150,000 r or 225,000 r results in a fall in the glyoxalase activity of the ceils. The inhibition is prevented by thepreincubation of the irradiated saline with catahse and is reversed by the addition of plasma, glucose, adenosine, and inosine to the cell suspension.An inhibition of the glyoxalase activity is also produced by the addition of Hg)2 to the suspension of erythrocytes. The inhibitory effect of H202 can be prevented and largely reversed by plasma, glucose, adenosine, and inosine. Methylglyoxal is also protective under these conditions.Hydrogen peroxide formed continuously and in low concentrations by enzyme systems appears to be more effective than added H~3~ in inhibiting the glyoxalase system. The inhibition by H~)v-producing enzyme systems is minimized by the addition of catalase, plasma, glucose, methylglyoxal, and to a lesser extent, by adenosine and inosine, and is accentuated by the addition of sodium azide.The results are discussed in relation to the role of H~O~ and catalase in the toxicity of ionizing radiations.The formation of hydrogen peroxide by the irradiation of aqueous solutions has been observed repeatedly (1, 2) and the considerable influence of this substance on many biological systems has encouraged a great deal of speculation, and considerable experimentation towards elucidating the role, if any, of H~O9 in the toxicity of ionizing radiations. The glyoxalase activity of intact erythrocytes is inhibited by x-radiation largely as a result of a decrease in the reduced glutathione level of the cells (3).

show abstract

“…A number of investigators have reported that on irradiation of aqueous solutions, whether with x-rays or with ultra-violet light, there is formation of some unknown substance which will produce inhibition of growth of protozoa (Taylor et al, 1933) inhibition of the fertilizing capacity of sea urchin sperm (Evans, 1947), inhibition of the growth of bacteria (Wyss et al, 1948), and increase in the mutation rate of v9. aureus to penicillin resistance (Stone et al, 1947).…”

mentioning

confidence: 99%

Studies on the Mechanism of Action of Ionizing Radiations. V. The Effect of Hydrogen Peroxide and of X-Ray Irradiated Sea Water on the Respiration of Sea Urchin Sperm and Eggs

Barrón¹,

Flood²,

Gasvoda³

1949

The Biological Bulletin

View full text Add to dashboard Cite

It has been known for some time (Risse, 1929;Fricke, 1934) that when water is irradiated with x-rays in the presence of oxygen there is formation of H 2 O2. Since H 2 O2 is a powerful oxidizing agent and it easily oxidizes sulfhydryl groups, it was reasonable to assume that this substance, if formed on irradiation, would contribute to the biological effects of ionizing radiations. In fact, Barren and Dickman (1949) on studying enzyme inhibitions by ionizing radiations, and Barron and Flood x on studying the oxidation of 2,3-dithiopropane and of glutathione by x-rays, were able to distinguish the H 2 O 2 contribution to this oxidation by the use of catalase. The French investigators Caillot (1941), andLatarjet (1942) have postulated that the primary effect of irradiation in aqueous solutions is H 2 O 2 formation, which would thus become of importance in the interpretation of the mechanism of ionizing radiations. The same view is held by Evans (1947) who found that the fertilizing power of sea urchin sperm is decreased when suspended in sea water irradiated with large doses of x-rays. Evans attributed this inhibition to the action of H 2 O 2 seemingly formed on irradiation of sea water. In living .cells the role of H 2 O 2 becomes more complicated because the sulfhydryl groups which might be oxidized by this agent not only are present in the protein moiety of enzymes, but also exist as non-protein sulfhydryl groups. We present in this paper experiments on the effect -of H 2 O 2 and of x-ray irradiated sea water on the respiration of sea urchin sperm. They do not support the belief that H 2 O 2 is an important factor in x-ray toxicity on sea urchin sperm. EXPERIMENTALSea urchin sperm was obtained as described previously , and in all experiments a dilution of 1 : 200 was used. Freshly filtered sea water was irradiated at room temperature in large cellophane dishes and immediately after irradiation the sperm suspension was added, enough to make the desired dilution of 1 : 200.The catalase added to irradiated sea water was prepared from beef liver according to Sunmer and Dounce (1939). H 2 O 2 was determined by the colorimetric method of Bonet-Maury (1944). An aliquot of the solution was taken (up to 1 Unpublished experiments.

show abstract

Studies on Protozoa, IV: Lethal Effects of the X-Radiation of a Sterile Culture Medium for Colpidium campylum

Cited by 26 publications

References 0 publications

Sensitization to Heat by X-Rays

Sensitization to Heat by X-Rays

The Relationship of Hydrogen Peroxide to the Inhibition of the Glyoxalase Activity of Intact Erythrocytes by X-Radiation

Studies on the Mechanism of Action of Ionizing Radiations. V. The Effect of Hydrogen Peroxide and of X-Ray Irradiated Sea Water on the Respiration of Sea Urchin Sperm and Eggs

Contact Info

Product

Resources

About