Laser Microirradiation of Chinese Hamster Cells at Wavelength 365 nm

Cells of a V79 subline of the Chinese hamster were microirradiated at wavelength 365 nm in the presence of the psoralen derivative, trioxsalen. Microirradiation was accomplished by a pulsed argon laser microbeam either in anaphase or in interphase 3 hr after mitosis. Inhibition of clonal growth and formation of micronuclei at the first postirradiation mitosis were observed after microirradiation of anaphase chromosomes and of small parts of the interphase nucleus. Microirradiation of the cytoplasm beside the interphase nucleus or between the sets of chromosomes moving apart from each other in anaphase did not produce these effects. Anaphase experiments showed that only the daughter cell which received microirradiated chromatin exhibited an abnormal growth pattern. Most interestingly, shattering of the whole chromosome complement could be induced by microirradiation of small parts of the interphase nucleus and post-treatment with caffeine. Since microirradiation of chromatin in the absence of psoralen was not effective, we consider formation of psoralen photoadducts to nucleic acids in microirradiated chromatin to be the specific cause of the effects. We suggest that DNA photolesions in chromosome segments present in the microirradiated part of the nucleus can induce shattering of all the chromosomes in the microirradiated nucleus. Several possibilities are discussed to explain this unexpected finding

A simple and versatile argon laser microbeam

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33682/1/0000194.pd

Ag Engineering and Agronomy Farm and Central Iowa Research Farms Summary

Includes Ag Engineering and Agronomy Farm Farm and Weather Summary, Central Iowa Farms Farm and Weather Summary and Project List

Ag Engineering/Agronomy Farm and Central Iowa Farms Summary

Contains: Ag Engineering and Agronomy Farm Farm and Weather Summary Central Iowa Farms Farm and Weather Summary Project Lis

Mitotic blockage following laser micro-irradiation of prosphase chromosomes

An argon laser microbeam was used to irradiate prophase chromosomes of the salamander () and the established cell of the rat kangaroo (PTK1, ). In both cell types mitosis was significantly blocked when irradiation occurred in early prophase regardless of whether or not the irradiated chromosomes were nucleola-associated. It was also determined that with identical irradiation conditions, the salamander cells were more susceptible to mitotic inhibition than the kangaroo cells. The results are compared with earlier studies performed with lower energy densities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34174/1/0000463.pd