Photoreactivation in Colpidium Colpoda

Giese, Arthur C.; Brandt, C. L.; Iverson, R.M.; Wells, Patrick H.

doi:10.2307/1538416

Cited by 22 publications

(10 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To determine whether the efficiency of a given dose of photoreversing blue light (4350 A monochromatic) could be increased in some other organism be- 6.40 485 sides T. pyriformis, a series of experiments was performed with Colpidium ¢olpoda. This organism was currently being used in the laboratory so that it was possible to apply the techniques for handling and photoreversal which had already been worked out (Giese et al, 1952). That flashing light is more effective than the same dosage of continuous light for photoreversing UV injury to Colpidium is seen in Fig.…”

Section: The Effect Of Intermittent Photoreversing Light In Colpidiummentioning

confidence: 99%

Increased Photoreversal of Ultraviolet Injury by Flashing Light

Christensen

Giese

1956

The Journal of General Physiology

Self Cite

View full text Add to dashboard Cite

1. Photoreversal of ultraviolet (UV) injury was studied in the ciliate protozoan Tetrahymena pyriformis (geleii) strain W, cultured in the absence of other living organisms. The division pattern of progeny of single animals was followed in hanging drop preparations. 2. A sublethal dose of 450 ergs/mm.2 of monochromatic UV of wave length 2654 A produces a lag before the first division followed by a period of cessation of fission after the second division. This cessation sometimes lasts as long as 6 weeks, during which time the animals become smaller and rounder and more opaque. Organisms about to resume division increase in size and transparency; after a few divisions the animals regain their normal division rate. 3. The effect of UV ranging in intensity from 5 to 15 ergs/mm.2/sec. was found to obey the reciprocity law quite well for the UV effect on the division pattern of T. pyriformis. However, the same dose at lower and at higher intensities was less effective. 4. The effect of a dose of UV delivered at high intensity (19 ergs/mm.2/sec.) could be increased by flashing the light, indicating that the system became saturated in the continuous light. 5. A photoreversing dose of monochromatic blue light of wave length 4350 A was found to be more effective when delivered as continuous light at a low intensity, or as intermittent light at a high intensity, rather than as continuous light at the high intensity—indicating that a dark mechanism participates in photoreversal. 6. The time for the dark reaction was determined to be of the order of a few hundredths of a second in experiments in which different lengths of dark period were used while maintaining a constant light period of 0.0025 second. 7. For Colpidium colpoda the efficiency of a given dose of photoreversing light was increased by flashing the light. 8. The present experiments are interpreted in terms of data available in the literature.

show abstract

Section: The Effect Of Intermittent Photoreversing Light In Colpidiummentioning

confidence: 99%

Increased Photoreversal of Ultraviolet Injury by Flashing Light

Christensen

Giese

1956

The Journal of General Physiology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Active metabolism stimulated by intake of food has been seen to favor resistance to UV in other species as well, e.g. Paramecium (Giese and Reed, 1940) and Colpidium (Giese et al, 1953(Giese et al, , 1954. In all three protozoans experiments indicate that physical screening cannot account for the increased resistance of fed animals to UV, since ingestion is not immediately followed by increased resistance to UV, but only after a lapse of time during which, presumably, the nutrient is incorporated into the protoplasm.…”

Section: Discussionmentioning

confidence: 98%

“…

Starvation increases the susceptibility of Paramecium and Colpidium to ultraviolet (UV) radiations (Giese and Reed, 1940;Giese et al, 1954). Injury to starved colpidia is found to be less readily photoreversed than that to well fed animals, eight times as many quanta of blue light per quantum UV being required for maximal photoreversal (Giese et a/., 1953).

…”

mentioning

confidence: 99%

The Effect of Nutritional State on Photoreversal of Ultraviolet Injuries in Didinium Nasutum

Brandt

Shepard

Giese

1955

The Journal of General Physiology

Self Cite

View full text Add to dashboard Cite

Starvation increases the susceptibility of Paramecium and Colpidium to ultraviolet (UV) radiations (Giese and Reed, 1940;Giese et al., 1954). Injury to starved colpidia is found to be less readily photoreversed than that to well fed animals, eight times as many quanta of blue light per quantum UV being required for maximal photoreversal (Giese et a/., 1953). Refeeding them with bacteria after UV but before blue light has little effect upon the degree of photoreversal (Giese eta/., 1954). Since it is difficult to tell how much food a bacterial feeder like Colpidium has ingested and how soon the food has been metabolized, the effect of feeding on UV injury and its photoreversal was studied with Didinium nasutura, a carnivorous ciliate. This species was chosen because its food intake can be easily observed under the microscope and regulated. It normally eats paramecia which can be grown under fairly controlled conditions. Therefore if the number of paramecia supplied to a didlnium is controlled, the quantity and quality of food intake is known. The effect of the nutritional state upon susceptibility to UV and on photoreversal of UV injury by visible light is reported below. Material and MethodsThe dirllnla were irradiated with monochromatic short UV (2654 A) the intensity of which, measured by a thermopile calibrated against U. S. Bureau of Standards' standard lamps, varied from 8.67 to 4.64 ergs/sec./mm, ffi during the course of the experiments. They were photoreversed with monochromatic blue light (4350 A), the intensity of which varied from 565 to 294 ergs/sec./mm. ~ One fraction of a population of irradiated didinia was illuminated within a few minutes after UV treatment; another was kept as a dark control (UV). The methods have been described in some detail in previous work with Colpidium (Giese el a/., 1952). All observations were made in red light which does not photoreactivate.Didinia were fed upon paramecia grown in test tubes on a single strain of bacteria in the manner previously described (Giese and Taylor, 1935). Freshly excysted didinia were much more constant in division rate and susceptibility to UV than *Supported in part by contract AT(11-1)-234 with the Atomic Energy Commission.

show abstract

“…The results reported here demonstrate that at least one of these possibilities exist in the egg of Smittia, and that this type of photorepair is biologically meaningful. It should be emphasized that efficient photorepair of damage caused by UV above 300 nm wavelength is not unique to Smittia but was also found in protozoa (Giese et al, 1952), Drosophila eggs (Levin and Kozlova, 1973), and the skin of man (Van der Leun and Stoop, 1969). These results indicate that light dependent counteraction to damage potentially caused by solar UV above 300 nm wavelength is a common feature of metazoa.…”

Section: Discussionmentioning

confidence: 99%

Compensation for solar UV damage by solar radiation of longer wavelengths (Smittia spec., Chironomidae, Diptera)

Kalthoff

1975

Oecologia

View full text Add to dashboard Cite

Photobiological experiments and laboratory observations on the egg deposition behaviour of Smittia were undertaken to assess the effect of different spectral ranges of solar radiation on inactivation and photoreactivation of the eggs.The egg deposition of Smittia is not confined to certain periods of the daily cycle, nor are the eggs hidden away even from bright laboratory light. Both the egg shells and the jelly of the clusters absorb UV poorly.An action spectrum was established for inactivation of eggs by exposition to ultraviolet radiation (UV) during intravitelline cleavage. It shows a pronounced peak at 295 nm and overlaps with the spectrum of the sunlight between 300 and 310 nm wavelength.The inactivating range of solar UV was substituted for by 305 nm radiation of 5 nm band with and a dose rate of 0.28 W/m, obtained from a monochromator. This "solar UV equivalent" caused inactivation of 50% of exposed eggs within 12 min, whereas exposition to full overhead sunlight produced the same effect only within 3 hrs.It is concluded that the inactivating effect of solar UV (300-310 nm) is counteracted by repair mechanisms requiring light of longer wavelengths (320-480 nm) which are also emitted by the sun.The type of photoreactivation described is difficult to understand within the established framework of nucleic acid repair. However, it seams to play a vital rôle in the survival of Smittia eggs under sunlight without need for pigmentation or shading.

show abstract

Photoreactivation in Colpidium Colpoda

Cited by 22 publications

References 11 publications

Increased Photoreversal of Ultraviolet Injury by Flashing Light

Increased Photoreversal of Ultraviolet Injury by Flashing Light

The Effect of Nutritional State on Photoreversal of Ultraviolet Injuries in Didinium Nasutum

Compensation for solar UV damage by solar radiation of longer wavelengths (Smittia spec., Chironomidae, Diptera)

Contact Info

Product

Resources

About