Changes of cell growth and magnetosome biomineralization in Magnetospirillum magneticum AMB-1 after ultraviolet-B irradiation

Abstract

Effects of ultraviolet radiation on microorganisms are of great interest in field of microbiology and planetary sciences. In the present study, we used Magnetospirillum magneticum AMB-1 as a model organism to examine the influence of ultraviolet-B (UV-B) radiation on cell growth and magnetite biomineralization of magnetotactic bacteria. Live AMB-1 cells were exposed to UV-B radiation for 60 s, 300 s and 900 s, which correspond to radiation doses of 120 J/m2, 600 J/m2 and 1800 J/m2, respectively. After irradiation, the amounts of cyclobutane pyrimidine dimers and reactive oxygen species of the cells were increased, and cell growth was stunted up to ~170 h, depending on the UV-B radiation doses. The UV-B irradiated cells also produced on average more magnetite crystals with larger grain sizes and longer chains, which results in changes of their magnetic properties