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Related Concept Videos

Plasmids01:28

Plasmids

Plasmids are extrachromosomal DNA molecules found in bacteria, archaea, and some eukaryotic microbes like yeast. These small, circular DNA structures typically contain fewer than 30 genes, although some may exist linearly. Plasmids vary in their number within a cell, known as copy number. Single-copy plasmids are present in one copy per cell and multi-copy plasmids are present in multiple copies, reaching over 100 copies per cell.Plasmids usually replicate independently of the chromosomal DNA...
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Inhibitors of Bacterial DNA Synthesis

Bacterial pathogens depend on precise and efficient DNA replication to sustain infection. Two type II topoisomerases—DNA gyrase and topoisomerase IV—are critical to this process, as they resolve DNA supercoiling and unlink chromosomes during replication. Fluoroquinolones, synthetic derivatives of quinolones, exploit this mechanism by stabilizing the transient DNA–enzyme cleavage complex, preventing strand religation, and causing lethal double-strand breaks. These antibiotics are selectively...

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Laser Microirradiation to Study In Vivo Cellular Responses to Simple and Complex DNA Damage
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Published on: January 31, 2018

Low-level infrared laser effect on plasmid DNA.

Adenilson Souza Fonseca1, Mauro Geller, Mario Bernardo Filho

  • 1Departamento de Ciências Fisiológicas, Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, Brazil. adnfonseca@ig.com.br

Lasers in Medical Science
|May 11, 2011
PubMed
Summary

Low-level infrared laser therapy can alter bacterial plasmids, affecting their transformation efficiency and survival in E. coli. Protocols must consider laser parameters and cell genetics for safe and effective treatment.

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Area of Science:

  • Photobiology
  • Molecular Biology
  • Laser Therapy

Background:

  • Low-level laser therapy (LLLT) exhibits biostimulative effects but its photobiological mechanisms and adverse effects remain unclear.
  • Understanding LLLT's impact on cellular components like bacterial plasmids is crucial for optimizing therapeutic applications.

Purpose of the Study:

  • To investigate the effects of low-level infrared laser on bacterial plasmids.
  • To evaluate laser-induced alterations in plasmid DNA and their impact on bacterial cell viability and transformation efficiency.

Main Methods:

  • Bacterial plasmids were analyzed using alkaline agarose gel electrophoresis to detect DNA lesions after infrared laser exposure.
  • Transformation efficiency and survival rates of various Escherichia coli strains (wild-type and DNA repair-deficient mutants) harboring plasmids were assessed post-laser treatment.

Main Results:

  • Pulsed infrared laser at 2,500 Hz altered plasmid electrophoretic profiles, unlike continuous wave or lower frequency pulsed modes.
  • Laser exposure modified plasmid transformation efficiency in wild-type and fpg/mutM(-) E. coli.
  • Survival of plasmids within fpg/mutM(-), xthA(-), and recA(-) E. coli strains was affected by laser treatment.

Conclusions:

  • Low-level infrared laser, particularly in high-frequency pulsed modes, impacts bacterial plasmids.
  • Laser therapy's effects on plasmid survival vary depending on bacterial DNA repair proficiency, necessitating tailored treatment protocols.