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Potential roles for DNA replication and repair functions in cell killing by streptomycin

M Zafri Humayun1, Vasudevan Ayyappan

  • 1Department of Microbiology and Molecular Genetics, Rutgers New Jersey Medical School, 225 Warren Street, Newark, NJ 07107, United States.

Mutation Research
|August 21, 2013
PubMed

Insights

Streptomycin kills bacteria by causing errors in protein production. Inhibiting DNA synthesis with hydroxyurea significantly reduces this killing effect, suggesting DNA replication is key to streptomycin

Area of Science:

  • Microbiology
  • Molecular Biology
  • Bacterial Physiology

Background:

  • Aminoglycoside antibiotics like streptomycin target bacterial ribosomes, causing mistranslation and inhibiting protein synthesis.
  • Unlike many other translation inhibitors, streptomycin exhibits bactericidal activity.
  • Emerging evidence links mistranslation to disruptions in DNA replication.

Purpose of the Study:

  • To investigate the role of DNA replication and repair in streptomycin-induced bacterial killing.
  • To determine if inhibiting DNA synthesis affects streptomycin's bactericidal efficacy.

Main Methods:

  • Treatment of bacterial cells with streptomycin alone and in combination with hydroxyurea (a DNA synthesis inhibitor).
  • Assessment of bacterial killing efficacy under various conditions.
  • Evaluation of hydroxyl radical scavengers (d-mannitol, thiourea) and an iron chelator (2,2'-dipyridyl).
  • Induction of the adaptive response to alkylation using methyl methanesulfonate.

Main Results:

  • Hydroxyurea significantly attenuated streptomycin-mediated bacterial killing.
  • Hydroxyl radical scavengers showed minimal protective effects.
  • The iron chelator 2,2'-dipyridyl inhibited killing, but this was attributed to blocking streptomycin uptake.
  • Pre-treatment with methyl methanesulfonate also attenuated streptomycin killing.

Conclusions:

  • Bacterial killing by streptomycin is significantly dependent on DNA replication processes.
  • DNA repair mechanisms may also play a role in cellular response to streptomycin.
  • These findings suggest a complex interplay between translation inhibition, DNA replication, and bacterial cell death.
Keywords:
Antibiotic uptakeDNA alkylation damageDNA replication and repairDipyridylHydroxyl radicalsMistranslationalkB

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