Mechanisms of enhanced bacterial endospore inactivation during sterilization by ohmic heating
| Autor: | Sudhir K. Sastry, Henry Jaeger, Peter Setlow, Felix Schottroff, Kai Reineke, Taras Pyatkovskyy |
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| Rok vydání: | 2019 |
| Předmět: |
Hot Temperature
Biophysics 02 engineering and technology Bacillus subtilis 01 natural sciences Endospore Heating chemistry.chemical_compound Bacterial Proteins Electricity Electric field Electrochemistry Spore germination Physical and Theoretical Chemistry Spores Bacterial biology fungi 010401 analytical chemistry Sterilization General Medicine Sterilization (microbiology) 021001 nanoscience & nanotechnology Dipicolinic acid biology.organism_classification 0104 chemical sciences Spore chemistry Mutation 0210 nano-technology Joule heating |
| Zdroj: | Bioelectrochemistry. 130:107338 |
| ISSN: | 1567-5394 |
| Popis: | During ohmic heating, the electric field may additionally inactivate bacterial endospores. However, the exact mechanism of action is unclear. Thus, a mechanistic study was carried out, investigating the possible target of electric fields inside the spore. Bacillus subtilis spores were heated by conventional and ohmic heating in a capillary system under almost identical thermal conditions. Wild-type (PS533) spores were used, as well as isogenic mutants lacking certain components known for their contribution to spores' heat resistance: small-acid soluble proteins (SASP) protecting DNA (PS578); the coat covering the spore (PS3328); and the spore germination enzyme SleB (FB122(+)). Treatment-dependent release of the spore core's depot of dipicolinic acid (DPA) was further evaluated. Up to 2.4 log10 additional inactivation of PS533 could be achieved by ohmic heating, compared to conventional heating. The difference varied for the mutants, with a decreasing difference indicating a decreased effect of the electric field and vice versa. In particular, mutant spores lacking SASPs showed a behavior more similar to thermal inactivation alone. The combination of heat and electric field was shown to be necessary for enhanced spore inactivation. Thus, it is hypothesized that either the heat treatment makes the spore susceptible to the electric field, or vice versa. |
| Databáze: | OpenAIRE |
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