A STUDY ON THE RADIOPROTECTIVE PROPERTY OF THIOUREA AGAINST RADIATION-INDUCED CHROMOSOME DAMAGE

1970 ◽  
Vol 12 (4) ◽  
pp. 685-688 ◽  
Author(s):  
S. B. Reddy
Keyword(s):  
Allium Cepa ◽  
Chromosome Aberrations ◽  
Chromosome Damage ◽  
Radioprotective Property ◽  
Root Tips ◽  
Anaphase Bridges ◽  
Chromosome Fragments ◽  
X Irradiation ◽  
Radiation Induced ◽  
Germinating Seeds

The protective ability of thiourea in five different concentrations ranging from 5 × 10−2M to 1 × 10−5M has been demonstrated on chromosome aberrations in root tips of Allium cepa exposed to 350r X-irradiation. It was shown that protection against radiation-induced chromosome fragments and anaphase bridges was attained when the germinating seeds had been treated with thiourea for 1 hour prior to irradiation.

Mouse one-cell embryos undergoing a radiation-induced G2 arrest may re-enter S-phase in the absence of cytokinesis

2002 ◽  
Vol 80 (7) ◽  
pp. 618-624 ◽  
Author(s):  
P Jacquet ◽  
J Buset ◽  
J Vankerkom ◽  
S Baatout ◽  
L de Saint-Georges ◽  
...  
Keyword(s):  
Calyculin A ◽  
Embryonic Cells ◽  
G2 Arrest ◽  
Cell Stage ◽  
Chromosome Fragments ◽  
X Irradiation ◽  
Radiation Induced ◽  
Mouse Zygotes ◽  
The One

PCC (premature chromosome condensation) can be used for visualizing and scoring damage induced by radiation in the chromatin of cells undergoing a G1 or G2 arrest. A method involving the fusion of irradiated single embryonic cells with single MI oocytes was used to induce PCC in mouse zygotes of the BALB/c strain, which suffer a drastic G2 arrest after X-irradiation (dose used 2.5 Gy). Other G2-arrested embryos were exposed in vitro to the phosphatase inhibitor calyculin A. Both methods furnished excellent chromosome preparations of the G2-arrested embryos. The mean number of chromosome fragments did not change significantly during G2 arrest, suggesting that zygotes of this strain are unable to repair DNA damage leading to such aberrations. Forty to fifty percent of the irradiated embryos were unable to cleave after G2 arrest and remained blocked at the one-cell stage for a few days before dying. PCC preparations obtained from such embryos suggested that about 30% of them had undergone a late mitosis not followed by cytokinesis and had entered a new DNA synthesis. These results are discussed in the light of recent observations in irradiated human cells deficient in the p53/14-3-3sigma pathway.Key words: PCC, embryo, oocyte, calyculin A, G2 arrest, cytokinesis.

The radioprotective effect of cysteine, AET and cystamine on chromosome damage in Allium cepa root tips

1963 ◽  
Vol 3 (1) ◽  
pp. 59-65 ◽  
Author(s):  
H. Dalen ◽  
R. Oftebro
Keyword(s):  
Allium Cepa ◽  
Radioprotective Effect ◽  
Chromosome Damage ◽  
Root Tips

CHROMOSOME ABERRATIONS PRODUCED BY 5-BROMODEOXYURIDINE WITH CONCURRENT EXPOSURE TO LONG WAVELENGTH UV IN ZEA MAYS ROOT TIP CELLS

1977 ◽  
Vol 19 (3) ◽  
pp. 447-459 ◽  
Author(s):  
R. S. Verma ◽  
J. E. Cummins ◽  
D. B. Walden
Keyword(s):  
Zea Mays ◽  
Chromosome Aberrations ◽  
Cesium Chloride ◽  
Root Tip ◽  
Chromosome Damage ◽  
Root Tips ◽  
Long Wavelength ◽  
Small Pool ◽  
Tip Cells ◽  
Root Tip Cells

The influence of bromodeoxyuridine (BrUrdR) on the pattern and level of chromosome damage in Zea mays L. root tip cells is described. In some experiments long wavelength ultraviolet light was employed to convert the bromodeoxyuridine in DNA to its photoproduct. BrUrdR treatment produced a marked decrease in the mitotic index and a high proportion of the mitotic cells bore chromosome damage. Following a BrUrdR treatment of 5 h the proportion of damaged cells increased from 20% to 60% during the 20 h following treatment; then the proportion decreased sharply to less than 20%. Root tips treated as above followed by an exposure to long wavelength ultraviolet radiation (UV) had a proportion of damaged cells (80% at 20 h) only slightly greater than those not exposed to UV up to 20 h after treatment. Unlike the unirradiated BrUrdR substituted root tips, the proportion of damaged cells remained high 25 h after treatment. Furthermore, the spectrum of chromosome aberrations differed between irradiated and unirradiated BrUrdR substituted cells. Root tips exposed to long wavelength UV alone showed some damage that was limited to a stage in the cell cycle of irradiated root tips. Analysis of the BrUrdR treated corn DNA by cesium chloride density centrifugation showed that BrUrdR substitution for thymidine in DNA was extensive. Further experiments demonstrated that a large BrUrdR pool was not carried into the rounds of replication following BrUrdR removal from the medium. Nevertheless a small pool of halogenated pyrimidine was observable after BrUrdR removal from the medium.

CYTOLOGICAL EFFECTS OF THE PESTICIDES PHOSDRIN AND BLADEX ON TRADESCANTIA AND VICIA FABA

1972 ◽  
Vol 14 (1) ◽  
pp. 157-165 ◽  
Author(s):  
M. Ahmed ◽  
W. F. Grant
Keyword(s):  
Vicia Faba ◽  
Chromosome Aberrations ◽  
Chromosomal Abnormalities ◽  
Floral Initiation ◽  
Root Tips ◽  
Methane Sulfonate ◽  
Ethyl Methane ◽  
Pollen Mother Cells ◽  
Chromosome Fragments ◽  
Mother Cells

The cytological effects of the insecticide Phosdrin (mevinphos) and the herbicide Bladex on root tips of Tradescantia and Vicia faba were observed and compared with those of the chemical mutagen ethyl methane sulfonate (EMS). In addition, plants of Vicia faba were sprayed prior to floral initiation and pollen mother cells examined for chromosomal abnormalities. Phosdrin and Bladex produced the same kinds of chromosome abnormalities as EMS, namely, fragments, bridges, multipolar anaphases and lagging chromosomes. Bladex produced a higher percentage (3.47%) of chromosome aberrations in root tips of Tradescantia than did Phosdrin (2.56%), but fewer in Vicia faba than did either EMS or Phosdrin. Bladex was more toxic to cells of Vicia faba. The greater percentage of chromosome fragments induced by both pesticides in Vicia faba may be the result of highly specific and localized action of the pesticides in heterochromatic regions. Vicia faba seedlings sprayed with Phosdrin had a greater percentage of chromosome aberrations in the pollen mother cells than were found in root tips after Phosdrin treatment. Bladex sprayed at the same concentration as Phosdrin (200, 400, 600 ppm) was lethal to the plants. The frequency of chromosomal aberrations induced by both pesticides deviated significantly from that of the control.

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