Mechanisms of Bacillus subtilis spore killing by and resistance to an acidic Fe-EDTA-iodide-ethanol formulation.
OBJECTIVE
To determine the mechanisms of Bacillus subtilis spore killing by and resistance to an acidic solution containing Fe(3+), EDTA, KI and ethanol termed the KMT reagent.


RESULTS
Wild-type B. subtilis spores were not mutagenized by the KMT reagent but the wild-type and recA spores were killed at the same rate. Spores (alpha(-)beta(-)) lacking most DNA-protective alpha/beta-type small, acid-soluble spore proteins were less resistant to the KMT reagent than wild-type spores but were also not mutagenized, and alpha(-)beta(-) and alpha(-)beta(-)recA spores exhibited nearly identical resistance. Spore resistance to the KMT reagent was greatly decreased if spores had defective coats. However, the level of unsaturated fatty acids in the inner membrane did not determine spore sensitivity to the KMT reagent. Survivors in spore populations killed by the KMT reagent were sensitized to killing by wet heat or nitrous acid and to high salt in plating medium. KMT reagent-killed spores had not released their dipicolinic acid (DPA), although these killed spores released their DPA more readily when germinated with dodecylamine than did untreated spores. However, KMT reagent-killed spores did not germinate with nutrients or Ca(2+)-DPA and were recovered only poorly by lysozyme treatment in a hypertonic medium.


CONCLUSIONS
The KMT reagent does not kill spores by DNA damage and a major factor in spore resistance to this reagent is the spore coat. KMT reagent treatment damages the spore's ability to germinate, perhaps by damaging the spore's inner membrane. However, this damage is not oxidation of unsaturated fatty acids.


CONCLUSIONS
These results provide information on the mechanism of spore resistance to and killing by the KMT reagent developed for killing Bacillus spores.
Shapiro
M P
MP
Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, 06032, USA.
Setlow
P
P
D000581:Amidohydrolases / Q000378:metabolism; D000588:Amines / Q000494:pharmacology; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D001426:Bacterial Proteins / Q000378:metabolism*; D024881:Drug Resistance, Bacterial; D004492:Edetic Acid / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005503:Food Additives / Q000494:pharmacology*; D005516:Food Microbiology; D006867:Hydrolases / Q000378:metabolism; D007501:Iron / Q000494:pharmacology*; D010848:Picolinic Acids / Q000494:pharmacology; D011193:Potassium Iodide / Q000494:pharmacology*; D013171:Spores, Bacterial / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D013501:Surface-Active Agents / Q000494:pharmacology; D013696:Temperature
D000588:Amines; D000891:Anti-Infective Agents, Local; D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D005231:Fatty Acids, Unsaturated; D005503:Food Additives; D010848:Picolinic Acids; C101656:SleB protein, Bacillus; D013501:Surface-Active Agents; D011193:Potassium Iodide; D000431:Ethanol; D004492:Edetic Acid; D007501:Iron; C433796:CwlJ protein, Bacillus subtilis; D006867:Hydrolases; D000581:Amidohydrolases; C004860:dipicolinic acid; C003935:dodecylamine