In vitro Production of Chromosomal Lesions with an Argon Laser Microbeam

THE development of the laser microbeam has made available an additional tool for selective probing of cellular organelles. Individual mitochondria have been studied successfully by Bessis and his colleagues, using a ruby laser microbeam 1 . The large mitochondria of beating rat heart cells have been extensively investigated using an argon laser microbeam arrangement (unpublished results of D. E. R. and N. Gamaleja). Another organelle which it would be important to manipulate is the nucleus with its nucleolar and chromosomal components. It seemed reasonable to assume that, given a compatible in vitro culture system and laser microbeam apparatus, lesions could be placed on predetermined sites of selected chromosomes.