Y Irradiation
Mostrando 25-36 de 116 artigos, teses e dissertações.
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25. Misrepair Mutagenesis in Bacteriophage T4
The T4 mutations px, y and 1206 inactivate an error-prone recombination-like repair system, reducing or abolishing mutagenesis by UV irradiation, MMS, and white light irradiation in the presence of the photosensitizer 8MOP. Both px and y increase some spontaneous mutation rates and slightly enhance proflavin mutagenesis; neither mutation affects thymineless
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26. Radiation Resistance and Injury of Yersinia enterocolitica
The D values of Yersinia enterocolitica strains IP134, IP107, and WA, irradiated at 25°C in Trypticase soy broth, ranged from 9.7 to 11.8 krad. When irradiated in ground beef at 25 and −30°C, the D value of strain IP107 was 19.5 and 38.8 krad, respectively. Cells suspended in Trypticase soy broth were more sensitive to storage at −20°C than those mixe
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27. Mechanism by which gamma irradiation increases the sensitivity of Salmonella typhimurium ATCC 14028 to heat.
Effects of irradiation and heating on survival of Salmonella typhimurium ATCC 14028 were examined by measuring DNA damage and the integrity of the cytoplasmic membrane. S. typhimurium cells fell into two distinct groups following heating: (i) heat-sensitive cells, which were rapidly inactivated at 65 degrees C and (ii) heat-resistant cells, which were only s
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28. Results of treating primary tumours of the trachea by irradiation.
Forty-four patients presented with primary tumours of the trachea over a 25-year period. Thirty-nine of them were treated by irradiation. Of these, 24 (61.5%) died as a result of their disease while 30% are either alive and well (4.4-11 years) or have died of intercurrent disease (average four years). Recurrences or metastases when they occurred were in the
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29. Inactivation and injury of Yersinia enterocolitica by radiation and freezing.
Cell inactivation and cell injury by irradiation and freezing of the potentially enteropathogenic, food-borne gram-negative rod Yersinia enterocolitica strain WA was investigated. The radiation dose necessary to kill 90% of the initial population, i.e., one D-value, was 10.0, 14,3, and 24.0 krad when irradiation was carried out at 2 to 0, -18, and -75 degree
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30. Resistance of some common fungi to gamma irradiation.
Ten species of fungi representing the genera Alternaria, Aspergillus, Caldosporium, Curvularia, Fusarium, and Penicillium were examined for their relative resistance to gamma irradiation from a 137Cs source. Inactivation doses for dematiaceous fungi in agar medium ranged from 0.6 to greater than 1.7 megarads, whereas those for moniliaceous fungi were less th
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31. X Irradiation of a Sensitive and a Resistant Strain of Escherichia coli under Controlled Oxygen Concentrations
van Soestbergen, A. A. (Brookhaven National Laboratory, Upton, N.Y.). X irradiation of a sensitive and a resistant strain of Escherichia coli under controlled oxygen concentrations. J. Bacteriol. 89:1032–1034. 1965.—Radiosensitive and radioresistant strains of Escherichia coli were given an X-ray dose of 4,544 rad at various controlled O2 concentrations,
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32. Nature and Consequences of Induced Chromosome Damage in Mammals
There are marked qualitative and quantitative differences in the patterns of chromosomal damage observed after irradiation of spermatogonia, spermatozoa and oocytes of mice. These differences often result from reduced or zero transmission of particular classes of abberration arising in pre-meiotic germ cells. Probably this is the reason why the level of X-ch
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33. Inhibition of initiation of simian virus 40 DNA replication during acute response of cells irradiated by ultraviolet light.
To study the mechanism by which ultraviolet (UV) light inhibits DNA replication, we examined the effects of UV 254 nm irradiation on the replication of simian virus 40 (SV40) DNA and SV40-based plasmid in monkey cells. The study was designed to determine the relative contributions made by inhibition of replication initiation and chain elongation to the immed
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34. Calorie restriction reduces the incidence of myeloid leukemia induced by a single whole-body radiation in C3H/He mice
Dietary restriction, especially caloric restriction, is a major modifier in experimental carcinogenesis and is known to decrease significantly the incidence of neoplasms. Gross and Dreyfuss [Gross, L. & Dreyfuss, Y. (1984) Proc. Natl. Acad. Sci. USA 81, 7596–7598; Gross, L. & Dreyfuss, Y. (1986) Proc. Natl. Acad. Sci. USA 83, 7928–7931] reported that a 3
The National Academy of Sciences of the USA.
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35. Artificial and Solar UV Radiation Induces Strand Breaks and Cyclobutane Pyrimidine Dimers in Bacillus subtilis Spore DNA
The loss of stratospheric ozone and the accompanying increase in solar UV flux have led to concerns regarding decreases in global microbial productivity. Central to understanding this process is determining the types and amounts of DNA damage in microbes caused by solar UV irradiation. While UV irradiation of dormant Bacillus subtilis endospores results main
American Society for Microbiology.
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36. Recombination-deficient mutant of Streptococcus faecalis.
An ultraviolet radiation-sensitive derivative of Streptococcus faecalis strain JH2-2 was isolated and found to be deficient in recombination, using a plasmid-plasmid recombination system. The strain was sensitive to chemical agents which interact with deoxyribonucleic acid and also underwent deoxyribonucleic acid degradation after ultraviolet irradiation. Th