Salt-mediated multicell formation in Deinococcus radiodurans.
The highly radiation-resistant tetracoccal bacterium Deinococcus radiodurans exhibited a reversible multi-cell-form transition which depended on the NaCl concentration in the medium. In response to 0.8% NaCl addition into the medium, the pair/tetrad (designated 2/4) cells in a young culture grew and divided but did not separate and became 8-, 16-, and 32-cell units successively. In exponential growth phase, the cells divided in a 16/32 pattern. Potassium ions were equally effective as Na+ in mediating this multicell-formation effect; Mg2+, Li+, and Ca2+ also worked but produced less multiplicity. This effect appears to be species specific. This-section micrographs revealed that in a 16/32-cell unit, eight 2/4 cells were encased in an orderly manner within a large peripheral wall, showing five cycles of septation. Our results suggest the presence of a salt-sensitive mechanism for controlling cell separation in D. radiodurans.
Chou
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Institute of Radiation Biology, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.
Tan
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ST
D002455:Cell Division / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D006094:Gram-Positive Bacteria / Q000166:cytology* / Q000254:growth & development / Q000528:radiation effects; D008854:Microscopy, Electron; D012965:Sodium Chloride / Q000494:pharmacology*; D014466:Ultraviolet Rays
D012965:Sodium Chloride