N-nitroso compounds, such as N-nitrosodiethylamine (NDEA), can be formed by the reaction of secondary amines with nitrosating agents, and are suspected to be involved in tumors in humans. NDEA has been considered a weak carcinogen in genotoxic assays probably due to the inefficient nitrosamine activation system that is used and/or to the efficient repair system. In this work, we evaluated the s...

Recent electron microscope studies of nuclei and chromosomes have shown that a microfibril from 100 to 200 A thick is the basic morphological unit of chromosomes. Chromosome fibrils of this dimension have been reported in the salivary gland chromosomes of Drosophila ~irilis (20, 21), in salivary chromosomes of D. melanogaster (9), in leptotene, pachytene, and metaphase chromosomes of Lilium (13...

Disinfection of surface drinking water, in particular water chlorination, produces many by-products with genotoxic and/or carcinogenic activity. The aim of this research was to evaluate the genotoxicity of surface water after treatment with different disinfectants by means of in situ plant genotoxicity assays. The study was carried out in a pilot plant using lake water after sedimentation and f...

Recent electron microscope studies of nuclei and chromosomes have shown that a microfibril from 100 to 200 A thick is the basic morphological unit of chromosomes. Chromosome fibrils of this dimension have been reported in the salivary gland chromosomes of Drosophila ~irilis (20, 21), in salivary chromosomes of D. melanogaster (9), in leptotene, pachytene, and metaphase chromosomes of Lilium (13...

N -nitroso compounds, such as N -nitrosodiethylamine (NDEA), can be formed by the reaction of secundary amines with nitrosating agents, and are suspected to be involved in tumors in humans. NDEA has been considered a weak carcinogen in genotoxic assays probably due to the inefficient nitrosamine activation system that is used and/or to the efficient repair system. In this work, we evaluated the...

Highly sensitive mutational responses of the stamen-hair system of some Tradescantia clones heterozygous for flower color (blue/pink, the blue being dominant) to low-level radiation and chemical mutagens, as demonstrated in the last decade, seem to endorse this system to be the most promising biological tester for detecting the genetic effects of mutagens at low levels. Two triploid (thus steri...

REVIOUS investigations have shown that infrared is effective in increasping the number of chromosomal aberrations induced by X-radiation ( KAUFMANN, HOLLAENDER and GAY 1946; SWANSON and HOLLAENDER 1946; YOST 1951). There has been little agreement at the interpretive level, however, on the mode of action of the infrared in producing this increase. Two hypotheses have been advanced. One proposes ...

C1G and K® uptake by cells of variegated leaves of Oenothera and Tradescantia having normal and mutated chloroplasts, respectively, have been investigated. Under our conditions light has no effect on ion uptake. C l e uptake is highly sensitive to FCCP in both green and mutated cells, while K® uptake is inhibited only in the green cells. Rates of ion uptake are higher in the green than in the m...

Irradiation of Tradescantia microspores does not increase subsequent sensitivity to x-rays as measured by the frequency of induced chromosomal aberrations curing the nuclear cycle. The slight decrease in sensitivity is to be expected because acentric fragments are less sensitive than the centric chromosomes. The physiological effects of x-rays appear to be of minor importance in causing injury ...