Micronuclei induction in human lymphocytes induced by carbon ions exposion along the penetrate depth of ions in water

Here we used cytokinesis-block micronucleus assay to measure the biological response along the penetrate depth of ions in water in human lymphocytes exposed to 100 MeV/u incident carbon ions in vitro. Polyethylene shielding was used to change the penetration depth of ions in water. A quantitative biological response curve was generated for micronuclei induction. The results showed a marked increase with the penetrate depth of ions in water in the micronuclei formation, which was consistent with a linearenergy- transfer dependent increase in biological effectiveness. The dose–response relationship for MN information was different at different penetrate depth of ions in water, at the 6 and 11.2 mm penetrate depth of ions in water, the dose–response relationships for the micronucleus frequencies induced by carbon ions irradiation were linear; while it was power function at 17.1 mm penetrate depth.

GENOTOXIC EFFECTS OF LINEAR ALKYL BENZENE SULFONATE, SODIUM PENTACHLOROPHENATE AND DICHROMATE ON TETRAHYMENA-PYRIFORMIS

DNA in macro- and micronuclei of Tetrahymena pyriformis treated with linear alkyl benzene sulfonate (LAS) and sodium pentachlorophenate (PCP-Na) were determined by microspectrophotometry. The effects on rate of formation of macronuclear DNA extrusion bodies were also studied. We found DNA content of micronuclei in 0.14 ppm LAS and 0.9 ppb PCP-Na was lower than in that of the control, and LAS was able to increase the formation rate of macronuclear DNA extrusion bodies (the formation rate was 54% in 11.3 ppm LAS and 25.6% in 16.7 ppm dichromate). We concluded that 0.14 ppm LAS (below the maximum acceptable toxicant concentration) was genotoxic, whereas 0.014 ppm LAS was not. Dichromate 0.05 ppm and 0.9 ppb PCP-Na, equal to and below the maximum acceptable toxicant concentration, respectively, were potentially genetoxic.

Kiitricha minuta n. Sp., a peculiar hypotrichous ciliate (Ciliophora, Spirotrichea) from the Yellow Sea

The morphology and infraciliature of a new ciliate, Kiitricha minuta n. sp., isolated from the Yellow Sea, were investigated using live observation and protargol impregnation. Kiitricha minuta represents a third member of the rarely known order Kiitrichida. It is unique in the subclass Hypotrichia in having many rows of small uniform cirri along the right side of the body and the dorsal kineties composed of dikinetids, most of which bear two cilia. Kiitricha minuta n. sp. is ovoid and measures about 60 x 45 mu m in vivo. It has a huge buccal cavity occupying about 80% of the body length, numerous body extrusomes, one macronucleus and two micronuclei, 27-27 adoral membranelles, 9-12 frontoventral cirral rows, a submarginal row of 7-9 cirri, 6 or 7 transverse cirri, and roughly 7-9 dorsal kineties. This new species differs distinctly from its only congener Kiitricha marina by its smaller size (60 mu m vs. 80-150 mu m), the presence of body extrusomes (vs. absent), the different macronuclear pattern (one vs. two nodules), and the lower number of frontoventral cirral rows (9-12 vs. 21-26), which terminate at the anterior two-thirds of body (vs. extend to the posterior). The new term "submarginal cirral row" is introduced to distinguish from the marginal cirral row in typical hypotrichs sensu lato. Based on our new observations and the literature, an improved diagnosis for the genus Kiitricha is provided and its phylogenetic importance is discussed.