A demonstration of the axial gradient by means of photolysis

Hinrichs, Marie A.

doi:10.1002/jez.1400410104

Cited by 14 publications

(4 citation statements)

References 8 publications

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“…Since lysis occurred rapidly and there was no apparent effect on the survivors, the concept of life shortening doesn't seem appropriate. Lysis of entire bodies took place in less than 24 h. These results are similar to those found with eosin yellow, another cytoplasm dye (Hinrichs, 1924(Hinrichs, , 1926Gurr, 1960).…”

Section: Effects Of Erythrosin Plus Visible Radiationsupporting

confidence: 81%

“…Lysis started at the thinner portions of the body, progressing first from the head, then from the tail, and lastly through the central portion of the body. The bilateral progression of lysis was similar to that described by Hinrichs (1924). Occasionally ( 2 4 % of the irradiated planarians), when only the head lysed and disappeared, a new head would eventually (within a week) be regenerated.…”

Section: Germicidal Uv Effectssupporting

confidence: 76%

“…These flatworms are relatively inexpensive to grow and maintain and have many biochemical and physiological characteristics similar to mammals (Best, 1983). The lethal effects of one photosensitizing compound, eosin yellow, on Dugesia dorotocephala has been reported (Hinrichs, 1924). Other studies have shown that different species of planarians, including D. dorotocephala, are sensitive to very high exposures of germicidal ultraviolet radiation (Merker and Gilbert, 1932;Hinrichs, 1924) and to near-ultraviolet radiation (Spencer and Klein, 1979;Barcelo, 1980).…”

Section: Introductionmentioning

confidence: 99%

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RESPONSES OF THE PLANARIAN Dugesia dorotocephala TO ULTRAVIOLET RADIATION OR PHOTOSENSITIZED TREATMENTS

Lytle¹,

Hsu²,

Faw³

et al. 1988

Photochem & Photobiology

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Abstract— The survival of the planarian Dugesia dorotocephala was measured following treatment with germicidal ultraviolet (UV) radiation, with the DNA photosensitizer 8‐methoxypsoralen (8‐MOP) plus near UV radiation, or with the cytoplasm photosensitizer erythrosin plus visible radiation. The typical morphological response of an irradiated animal was lysis, with the head being the most sensitive part. All the survival curves had substantial shoulders. Treatments whose primary target was likely to be DNA (UV irradiation or 8‐MOP plus near UV irradiation) resulted in lysis of part of the planarian population which commenced 24 h or more after treatment and continued over several days. The treatment whose primary target was likely to be the membranes of the planarian (erythrosin plus visible irradiation) resulted in lysis mostly during the first few hours after treatment. Thus an easily discerned endpoint, lysis, can be used for D. dorotocephala to evaluate photosensitizing compounds, where the kinetics of lysis may differentiate among compounds whose modes of action are different.

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Section: Effects Of Erythrosin Plus Visible Radiationsupporting

confidence: 81%

Section: Germicidal Uv Effectssupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

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RESPONSES OF THE PLANARIAN Dugesia dorotocephala TO ULTRAVIOLET RADIATION OR PHOTOSENSITIZED TREATMENTS

Lytle¹,

Hsu²,

Faw³

et al. 1988

Photochem & Photobiology

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“…Similar to the effects observed with other organisms (3,4), the age of the yeast culture has a marked influence on the relative resistance of the cells to lethal irradiation, as measured by the energy required to suppress budding (2). This is illustrated by a comparison of the results obtained on irradiating two cultures of widely different periods of incubation, (A) a 24 hour culture and (B) a 15 day culture of yeast, both incubated at 25°C.…”

Section: Age Of the Cellsmentioning

confidence: 78%

Results of Irradiating Saccharomyces With Monochromatic Ultra-Violet Light

Oster

1934

Journal of General Physiology

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It has been shown previously (1, 2) that the action of monochromatic ultra-violet radiation on the yeast Saccharomyces cerevisiae is not an all or none effect, but is a graded result varying from induction of simple inability to form normal sized colonies to "death" of the ~ell, through different degrees of damage, and involving in some stages the formation of giant cells. The mean "survival" curves for irradiated 24 hour cultures (2) resemble the curve for a first order process, but on this assumption divergences indicate the presence of modifying factors.The present paper deals with several factors which may modify the absorption of energy and the cell processes resulting from irradiation of yeast with ultra-violet light. Age of the CellsSimilar to the effects observed with other organisms (3, 4), the age of the yeast culture has a marked influence on the relative resistance of the cells to lethal irradiation, as measured by the energy required to suppress budding (2). This is illustrated by a comparison of the results obtained on irradiating two cultures of widely different periods of incubation, (A) a 24 hour culture and (B) a 15 day culture of yeast, both incubated at 25°C. and irradiated in a large quartz monochromator at the wave-length 2535 A. u. as previously described (2) after inoculation on malt agar contained in small Petri plates. As shown in Fig. 1, from 20 to 50 per cent more incident energy to produce a given effect is required for the 15 day culture than for the 24 hour cultures. This is best explained on the basis that the greater 243

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Modification of development on the basis of differential susceptibility to radiation. IV. Chick embryos and ultraviolet radiation

Hinrichs

1927

J. Exp. Zool.

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FORTY-FIVE FIGURESChick embryos have long been favorite subjects for the study of experimental teratology, yet anyone who has worked extensively with them can testify to the high degree of individual variability of the eggs and to the hazards attending the long dcvelopmental period under artificial conditions of incubation. When, however, large numbers of eggs are used (about seventy dozen in series B of these experiments) and development is allowed to proceed only to the second or third day, the percentage of normal embryos in the control series is found to be somewhat higher than is ordinarily to be expected.Previous experimenters have used various physical and chemical agents before, and during a part or the whole, of the incubation period. The injection of chemicals, bacteria, and the infected blood of animals under the shell, the subjection of the developing embryo to anesthetics, cyanides, noxious gases, decreased oxygen tension, or to x-ray and radium radiations, to changes in temperature, and to mechanical, electrical, and magnetic influences, all indicate that it is relatively easy to interfere with, or even completely inhibit, Brain and eye defects, katadidymy, and modifications of the developing somite region are frequently described as results of such experimental procedure. Dareste ( '91) and Stockard ( '21) attribute such abnormalities to 'developmental arrests' at 'critical periods' in development. While it is true that developmental modifications of particular organs or regions of the body can to some extent be controlled and can most easily be brought about when exposures to noxious agents or.conditions are made at a definite period of development prior to the time of normal appearance of that organ (Stockard, '21, and Hinrichs, '25), it is also true that the same modifications appear following exposures at a much earlier period of development, e.g., before fertilization, or before incubation, as in some of the experiments about to be described.Ultraviolet radiation, with its rapid, clean-cut action, is a very effective medium €or the production of abnormalities, since the time of its action can be more simply controlled than can that of most chemicals, although a latent period and some degree of 'hang-over' do appear.The results reported in this paper and in previous studies with radiation seem to indicate that, in general, the later an organ appears in development, the longer is its 'critical period,' that is, the greater the period during which it is possible to modify its development. While it is possible in some forms, for example, Arbacia (Hinrichs, '26 a, '26 b) and Fundulus (Hinrichs, 'as), to produce the same types of abnormality by exposures to radiation before f ertilizatioii as at various intervals after fertilization, the largest percentages of abnormalities in the development of a given region are produced when exposures are made during a period of maximum activity of that region. Such a period of See L. H. IIyman ('27 a ) for a critical review of the literature on experiniental ...

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A demonstration of the axial gradient by means of photolysis

Cited by 14 publications

References 8 publications

RESPONSES OF THE PLANARIAN Dugesia dorotocephala TO ULTRAVIOLET RADIATION OR PHOTOSENSITIZED TREATMENTS

RESPONSES OF THE PLANARIAN Dugesia dorotocephala TO ULTRAVIOLET RADIATION OR PHOTOSENSITIZED TREATMENTS

Results of Irradiating Saccharomyces With Monochromatic Ultra-Violet Light

Modification of development on the basis of differential susceptibility to radiation. IV. Chick embryos and ultraviolet radiation

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