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Effect of mechanical abrasion on the viability, disruption and germination of spores of Bacillus subtilis
Author(s) -
Jones C.A.,
Padula N.L.,
Setlow P.
Publication year - 2005
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2005.02744.x
Subject(s) - spore , germination , bacillus subtilis , microbiology and biotechnology , abrasion (mechanical) , bacterial spore , spore germination , biology , chemistry , botany , endospore , bacteria , materials science , composite material , genetics
Aims: To elucidate the factors influencing the sensitivity of Bacillus subtilis spores in killing and disrupting by mechanical abrasion, and the mechanism of stimulation of spore germination by abrasion. Methods and Results: Spores of B. subtilis strains were abraded by shaking with glass beads in liquid or the dry state, and spore killing, disruption and germination were determined. Dormant spores were more resistant to killing and disruption by abrasion than were growing cells or germinated spores. However, dormant spores of the wild‐type strain with or without most coat proteins removed, spores of strains with mutations causing spore coat defects, spores lacking their large depot of dipicolinic acid (DPA) and spores with defects in the germination process exhibited essentially identical rates of killing and disruption by abrasion. When spores lacking all nutrient germinant receptors were enumerated by plating directly on nutrient medium, abrasion increased the plating efficiency of these spores before killing them. Spores lacking all nutrient receptors and either of the two redundant cortex‐lytic enzymes behaved similarly in this regard, but the plating efficiency of spores lacking both cortex‐lytic enzymes was not stimulated by abrasion. Conclusions: Dormant spores are more resistant to killing and disruption by abrasion than are growing cells or germinated spores, and neither the complete coats nor DPA are important in spore resistance to such treatments. Germination is not essential for spore killing by abrasion, although abrasion can trigger spore germination by activation of either of the spore's cortex‐lytic enzymes. Significance and Impact of the Study: This work provides new insight into the mechanisms of the killing, disruption and germination of spores by abrasion and makes the surprising finding that at least much of the spore coat is not important in spore resistance to abrasion.