Summery: This was a test of Mn (manganese) in Deinococcus Radiodurans, testing it's effect, etc. Two test groups were conducted one of Mn (manganese) and two days of waiting (group A) and one of MnSO- (manganese solphate) and waiting of 6 days (group B). These tests were enacted on 14 hour old D. Radiodurans. Group B did not form toroids and became radio-sensitive. It is assumed that toroids are part of the reason for D. Radiodurans radio-resistance. Group A failed to form compartments or membrane orifices (which can be problematic for a bacterium).
"Transmission electron micrographs of MnSO4-treated D. radiodurans. MnSO4(100 μM) was added to the growth medium at the late logarithmic phase (14 hours old), and the cells were incubated for an additional (A) 48 hours or (B) 6 days. Bacteria exposed to Mn2+ formed aggregates but were noncompartmentalized and had no detectable membrane orifices. (C to E) Different morphologies exhibited by DNA-stained cells (10) exposed to MnSO4 for 6 days, showing that in these cells, genomes, which are darkly stained, do not form toroids. BecauseD. radiodurans cells exposed to large extracellular concentrations of Mn2+ become radiation sensitive (21), the absence of DNA toroids indicates that toroidal packaging is correlated with radioresistance. Scale bars, 500 nm." Science 10 January 2003: Vol. 299 no. 5604 pp. 254-256 DOI: 10.1126/science.1077865
Smadar Levin-Zaidman1,
Joseph Englander1,
Eyal Shimoni1,
Ajay K. Sharma2,
Kenneth W. Minton3,
Abraham Minsky1,*