Differential damage in bacterial cells by microwave radiation on the basis of cell wall structure.

Applied and environmental microbiology · 2000 · Mixed · Low evidence

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MixedLow evidencePaper 6371

Study snapshot

PublicationApplied and environmental microbiology · 2000

Study typein_vitro

Reported directionMixed

Evidence ratingLow

Abstract

Microwave radiation in Escherichia coli and Bacillus subtilis cell suspensions resulted in a dramatic reduction of the viable counts as well as increases in the amounts of DNA and protein released from the cells according to the increase of the final temperature of the cell suspensions. However, no significant reduction of cell density was observed in either cell suspension. It is believed that this is due to the fact that most of the bacterial cells inactivated by microwave radiation remained unlysed. Scanning electron microscopy of the microwave-heated cells revealed severe damage on the surface of most E. coli cells, yet there was no significant change observed in the B. subtilis cells. Microwave-injured E. coli cells were easily lysed in the presence of sodium dodecyl sulfate (SDS), yet B. subtilis cells were resistant to SDS.

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typein_vitro

Effect directionmixed

PopulationNot supplied

Sample sizeNot supplied

Exposuremicrowave

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Microwave radiation of Escherichia coli and Bacillus subtilis suspensions was associated with a dramatic reduction in viable counts and increased DNA and protein release as final suspension temperature increased, while cell density did not significantly decrease. Scanning electron microscopy showed severe surface damage in most E. coli cells but no significant change in B. subtilis; microwave-injured E. coli were easily lysed with SDS whereas B. subtilis were resistant.

Outcomes measured

bacterial viable counts
DNA release from cells
protein release from cells
cell density
cell lysis susceptibility (SDS)
cell surface damage (scanning electron microscopy)

Limitations

Microwave exposure parameters (e.g., frequency, power/SAR, duration) are not reported in the abstract.
Effects are described as varying with final temperature, suggesting thermal contributions; non-thermal effects cannot be determined from the abstract.
In vitro bacterial cell suspensions; findings may not generalize beyond these organisms/conditions.
Sample size and statistical details are not provided in the abstract.

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "microwave",
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "bacterial viable counts",
    "DNA release from cells",
    "protein release from cells",
    "cell density",
    "cell lysis susceptibility (SDS)",
    "cell surface damage (scanning electron microscopy)"
  ],
  "main_findings": "Microwave radiation of Escherichia coli and Bacillus subtilis suspensions was associated with a dramatic reduction in viable counts and increased DNA and protein release as final suspension temperature increased, while cell density did not significantly decrease. Scanning electron microscopy showed severe surface damage in most E. coli cells but no significant change in B. subtilis; microwave-injured E. coli were easily lysed with SDS whereas B. subtilis were resistant.",
  "effect_direction": "mixed",
  "limitations": [
    "Microwave exposure parameters (e.g., frequency, power/SAR, duration) are not reported in the abstract.",
    "Effects are described as varying with final temperature, suggesting thermal contributions; non-thermal effects cannot be determined from the abstract.",
    "In vitro bacterial cell suspensions; findings may not generalize beyond these organisms/conditions.",
    "Sample size and statistical details are not provided in the abstract."
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "microwave radiation",
    "Escherichia coli",
    "Bacillus subtilis",
    "cell wall structure",
    "viability",
    "DNA release",
    "protein release",
    "scanning electron microscopy",
    "SDS lysis",
    "thermal effects"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1128/aem.66.5.2243-2247.2000
PubMed: 10788410

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