[Production and releasing sites of superoxide anion in phytopathogenic bacteria].

Many phytopathogenic bacteria were founded to release the superoxide anion (O2-) by themselves from different sites and the production of O2- was related to the pathogenicity of strains. The presences of O2- in cytomembrane, cell wall and filtrate were confirmed by chemical method and electron spin resonance (ESR). The results show that filtrate may be the primary site of O2- production due to its higher O2- generating activity either in the presence or the absence of DDC.

Observation of DNA damage of human hepatoma cells irradiated by heavy ions using comet assay.

Aim: Now many countries have developed cancer therapy with heavy ions, especially in GSI (Gesellschaft f r Schwerionenforschung mbH, Darmstadt, Germany), remarkable results have obtained, but due to the complexity of particle track structure, the basic theory still needs further researching. In this paper, the genotoxic effects of heavy ions irradiation on SMMC-7721 cells were measured using the single cell gel electrophoresis (comet assay). The information about the DNA damage made by other radiations such as X-ray, gamma-ray, UV and fast neutron irradiation is very plentiful, while little work have been done on the heavy ions so far.