Response of newt larvae to X-irradiation

1970 ◽  
Vol 48 (5) ◽  
pp. 1017-1021
Author(s):  
G. B. Friedmann ◽  
H. M. McCurdy ◽  
F. T. Algard
Keyword(s):  
Life Span ◽  
Dose Response ◽  
Progenitor Cell ◽  
X Rays ◽  
Cell Type ◽  
Taricha Torosa ◽  
Age Dependent ◽  
X Irradiation ◽  
Complete Metamorphosis

Graded doses of from 200 to 2000 rad of x-rays were administered to premetamorphic Taricha torosa larvae of various ages. General stunting, specific malformation, pigmentary damage, and a very shortened life-span occurred at all doses. There is an age-dependent dose response; some animals exposed to 200 and 600 rad survived to complete metamorphosis. Evidence is presented supporting a view that postmetamorphic epidermal melanocytes may be derived largely by division of an unpigmented progenitor cell type.

Responses of metamorphosing Taricha torosa to x rays

1974 ◽  
Vol 52 (6) ◽  
pp. 671-676
Author(s):  
H. M. McCurdy ◽  
F. T. Algard ◽  
G. B. Friedmann
Keyword(s):  
Single Dose ◽  
Sample Population ◽  
X Rays ◽  
Larval Form ◽  
Triggering Mechanism ◽  
Pigment Pattern ◽  
Taricha Torosa ◽  
Complete Metamorphosis

A single dose of 1000 rads of x rays administered to metamorphosing Taricha torosa larvae interferes selectively with some elements of the metamorphosing process without, apparently, affecting any major triggering mechanism. Though the predominant result is a failure to complete metamorphosis, metamorphosed irradiates showing larval pigmentation, vestigial gills, and non-protuberant eyes have been observed. Arrest of the normal thickening of the epidermis during metamorphosis and of the associated development of the epidermal melanophores is followed by regression of the pigment pattern to the larval form. This 1000-rad dose appears to kill half of a sample population in 30 days. A single dose of 200 rads, while allowing completion of metamorphosis, is fatal within some 3 months. The metamorphosed animals show predominantly adult characteristics.

scholarly journals RESPONSE OF POTASSIUM RETENTIVITY AND SURVIVAL OF YEAST TO FAR-ULTRAVIOLET, NEAR-ULTRAVIOLET AND VISIBLE, AND X-RADIATION

1958 ◽  
Vol 41 (4) ◽  
pp. 693-702 ◽  
Author(s):  
A. K. Bruce
Keyword(s):  
Yeast Cell ◽  
Dose Response ◽  
X Rays ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Differential Effects ◽  
Near Ultraviolet ◽  
X Irradiation ◽  
Far Ultraviolet ◽  
Control Survival

Potassium retentivity and survival of yeast were studied after exposure to various kinds and conditions of irradiation. The radiations used were: 2537 A ultraviolet, 3500 to 4900 A long-ultraviolet and short visible, and 250 kvp1 x-rays. Both potassium retentivity and survival are decreased by these radiations. The dose-response of survival is about 16 times as sensitive as is potassium retentivity after 2537 A irradiation. Potassium retentivity is about twice as sensitive as survival after irradiation of 3500 to 4900 A. Survival after x-irradiation under aerobic conditions is five times as sensitive as potassium retentivity. Survival of cells irradiated with x-rays under anaerobic conditions was about half as sensitive as under aerobic conditions. The response of potassium retentivity to x-radiation at 25°C. under anaerobic conditions is only slightly affected below 160 kr, at which dose the slope abruptly increases to that obtained under aerobic conditions; lowering the temperature to 0°C. moves this point to about 300 kr. These differential effects are indicative of interaction of radiations with the yeast cell at sites that independently control survival and the retention of potassium.

Acute and long-term effects of X-irradiation on skeletal growth in the rat

1964 ◽  
Vol 207 (6) ◽  
pp. 1447-1451 ◽  
Author(s):  
Richard D. Phillips ◽  
Donald J. Kimeldorf
Keyword(s):  
Life Span ◽  
End Of Life ◽  
Skeletal Growth ◽  
Sublethal Dose ◽  
X Rays ◽  
Long Term Effects ◽  
Bone Length ◽  
X Irradiation ◽  
Tibia Length

The early and long-term effects of X-irradiation on skeletal growth were investigated with respect to the age at exposure. Rats exposed at a juvenile age (37 days) to a sublethal dose (430 rad) exhibited a retardation in femur, tibia, and tail growth within 14 days after exposure. The maximal deficit was attained within 30 days after exposure and remained approximately constant for the next 300 days. In animals which were exposed to X-rays as young adults (101 days of age), femur and tibia length did not differ from those of controls for the first 2 months after exposure. However, there was a deficit in femur and tibia length in these animals at the end of life span. The magnitude of the bone length reduction at the end of life span was dose dependent. The two major differences in response between the two age groups were the time course of the radiation effect on growth and the magnitude of the deficit. The reduction in bone length occurred faster and was greater in the younger irradiated group.

Eds Of Radioactive Particles By Self-Induced Fluorescence

1990 ◽  
Vol 48 (2) ◽  
pp. 238-239
Author(s):  
Gregory L. Finch ◽  
Richard G. Cuddihy
Keyword(s):  
Electron Beam Irradiation ◽  
Nuclear Reactor ◽  
X Rays ◽  
Reactor Accident ◽  
Internal Radiation ◽  
X Ray ◽  
External Sources ◽  
X Irradiation ◽  
Available Information ◽  
Individual Particles

The elemental composition of individual particles is commonly measured by using energydispersive spectroscopic microanalysis (EDS) of samples excited with electron beam irradiation. Similarly, several investigators have characterized particles by using external monochromatic X-irradiation rather than electrons. However, there is little available information describing measurements of particulate characteristic X rays produced not from external sources of radiation, but rather from internal radiation contained within the particle itself. Here, we describe the low-energy (< 20 KeV) characteristic X-ray spectra produced by internal radiation self-excitation of two general types of particulate samples; individual radioactive particles produced during the Chernobyl nuclear reactor accident and radioactive fused aluminosilicate particles (FAP). In addition, we compare these spectra with those generated by conventional EDS.Approximately thirty radioactive particle samples from the Chernobyl accident were on a sample of wood that was near the reactor when the accident occurred. Individual particles still on the wood were microdissected from the bulk matrix after bulk autoradiography.

scholarly journals THE INTERCELLULAR DISTRIBUTION OF MUTATIONS INDUCED IN OOCYTES OF DROSOPHILA MELANOGASTER BY CHEMICAL AND PHYSICAL MUTAGENS

Genetics ◽  
1979 ◽  
Vol 92 (1) ◽  
pp. 151-160
Author(s):  
H Traut
Keyword(s):  
Drosophila Melanogaster ◽  
Mitomycin C ◽  
Mutation Frequency ◽  
Lethal Mutation ◽  
X Rays ◽  
Mutagenic Treatment ◽  
X Chromosomes ◽  
Recessive Lethal ◽  
Lethal Mutations ◽  
X Irradiation

ABSTRACT When females of Drosophila melanogaster are treated with chemical or physical mutagens, not only in one but also in both of the two homologous X chromosomes of a given oocyte, a recessive sex-linked lethal mutation may be induced. A method is described that discriminates between such "single" and "double mutations." A theory is developed to show how a comparison between the expected and the observed frequency of double mutations yields an indication of the intercellular distribution (random or nonrandom) of recessive lethal mutations induced by mutagenic agents in oocytes and, consequently, of the distribution (homogeneous or nonhomogeneous) of those agents.—Three agents were tested: FUdR (12.5, 50.0 and 81.0,μg/ml), mitomycin C (130.0 μg/ml) and X rays (2000 R, 150 kV). After FUdR feeding, no increase in the mutation frequency usually observed in D. melanogaster without mutagenic treatment was obtained (u=0.13%, namely three single mutations among 2332 chromosomes tested). After mitomycin C feeding, 104. single and three double mutations were obtained. All of the 50 mutations observed after X irradiation were single mutations. The results obtained in the mitomycin C and radiation experiments favor the assumption of a random intercellular distribution of recessive lethal mutations induced by these two agents in oocytes of D. melanogaster. Reasons are discussed why for other types of mutagenic agents nonrandom distributions may be observed with our technique.

A multitype decomposable age-dependent branching process and its applications

1995 ◽  
Vol 32 (3) ◽  
pp. 591-608 ◽  
Author(s):  
Chinsan Lee ◽  
Grace L. Yang
Keyword(s):  
Tumor Growth ◽  
Life Span ◽  
Growth Rates ◽  
Exponential Growth ◽  
Branching Process ◽  
Asymptotic Formulas ◽  
Stage Model ◽  
Two Stage ◽  
Markov Branching Process ◽  
Age Dependent

Asymptotic formulas for means and variances of a multitype decomposable age-dependent supercritical branching process are derived. This process is a generalization of the Kendall–Neyman–Scott two-stage model for tumor growth. Both means and variances have exponential growth rates as in the case of the Markov branching process. But unlike Markov branching, these asymptotic moments depend on the age of the original individual at the start of the process and the life span distribution of the progenies.

Effect of massive X-irradiation on proteins and protein synthesis in peanut cotyledons

1968 ◽  
Vol 46 (7) ◽  
pp. 685-689 ◽  
Author(s):  
R. B. van Huystee
Keyword(s):  
Gel Electrophoresis ◽  
De Novo ◽  
Protein Biosynthesis ◽  
Water Soluble ◽  
X Rays ◽  
Soluble Protein Content ◽  
De Novo Biosynthesis ◽  
Water Soluble Protein ◽  
Radiation Resistant ◽  
X Irradiation

Peanut seeds were irradiated with 500 kR of X rays and stored for 6 weeks. The cotyledons from 3-day-old seedlings were harvested, and incubated with leucine-14C. The water-soluble protein content of those cotyledons was half to one-third that of the non-irradiated cotyledons. Protein biosynthesis in the irradiated cotyledons was equally reduced to one-third or less of control. Separation of the extracted proteins by acrylamide-gel electrophoresis suggested that there may be a larger amount of small-molecular proteins in the irradiated system. De novo biosynthesis after irradiation was restricted in all protein fractions. Enzyme activity was also severely restricted. No particular radiation-resistant isoenzyme of peroxidase could be detected.

Developmental effects of X-irradiation of early Drosophila embryos

Development ◽  
1977 ◽  
Vol 39 (1) ◽  
pp. 253-259
Author(s):  
M. Bownes ◽  
L. A. Sunnell
Keyword(s):  
Early Embryogenesis ◽  
X Rays ◽  
X Ray ◽  
Developmental Effects ◽  
Morphological Defects ◽  
X Irradiation ◽  
Drosophila Embryos ◽  
Adult Cells

Drosophila embryos were treated at specific stages during early embryogenesis with various doses of X-irradiation. The lethality at various times during development was established and pattern defects in the adults noted. It was observed that the most sensitive stages of embryogenesis to X-ray-induced lethality were also the stages where most morphological defects were found in the adults which emerged. This suggests that presumptive larval and adult cells are sensitive to X-rays at the same stages of embryogenesis.

Proliferation and differentiation potential of rat forebrain oligodendroglial progenitors both in vitro and in vivo

Development ◽  
1991 ◽  
Vol 111 (4) ◽  
pp. 1061-1080 ◽  
Author(s):  
R. Hardy ◽  
R. Reynolds
Keyword(s):  
Progenitor Cell ◽  
Neonatal Rat ◽  
Myelin Proteins ◽  
Brdu Incorporation ◽  
Cell Type ◽  
Differentiation Potential ◽  
Serum Free ◽  
Rat Forebrain

We have followed the development of the O-2A progenitor cell from the neonatal rat forebrain, both in dissociated cell culture and in cryostat sections, using immunocytochemical techniques employing a panel of antibodies that recognise the cells at different stages of their development. This included the monoclonal antibody LB1, which binds to the surface ganglioside GD3 expressed on O-2A progenitor cells. In secondary cultures enriched for O-2A progenitors maintained in a serum-free chemically defined medium, a large proportion of the cells are primed to differentiate into oligodendroglia and go on to express the oligodendroglial specific surface glycolipid galactocerebroside (GC) and then the myelin proteins CNP and MBP. However, a significant proportion of immature bipolar GD3+ cells remained after 6 days in secondary culture. It appears that not all the O-2A progenitors in our cultures differentiate immediately and some cells remain in an undifferentiated state and divide to replenish progenitor numbers. We have also identified in our cultures a small apolar GD3- cell, which when isolated differentiated into a GD3+ bipolar O-2A progenitor cell. We have termed this cell type a preprogenitor. The differentiation of this cell type into O-2A progenitors may be the source of the immature GD3+ cells present at the later stages of our secondary cultures. The proliferative profile of the cultures was studied using 5′bromo-2-deoxyuridine (BrdU) incorporation as an index of mitosis. Only the immature, bipolar O-2A progenitors were seen to divide at any time in serum-free culture. Neither the more mature multipolar O-2A cells nor the oligodendroglia were seen to divide. The developmental profile of the O-2A cells in the rat forebrain in vivo showed a largely similar progression to that in culture, with a time lag of at least 6 days between GD3 expression and the onset of myelination. BrdU incorporation studies in vivo also showed that the GD3+ progenitor cell is mitotic whereas the GC(+)-expressing oligodendroglia is not. We have shown that there are several significant alterations in the timing of antigen expression in both O-2A progenitors and oligodendroglia in vitro compared to that seen in vivo.

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