Related Experiment Video

Updated: Sep 2, 2026

Inducing a Site Specific Replication Blockage in E. coli Using a Fluorescent Repressor Operator System
11:19

Inducing a Site Specific Replication Blockage in E. coli Using a Fluorescent Repressor Operator System

Published on: August 21, 2016

DNA intercalating drugs inhibit positive supercoiling induced by novobiocin in halophilic archaea

D Gadelle1, P Forterre

  • 1Institute de Génétique et Microbiologie, Université Paris-Sud, CNRS, URA 1352, Orsay, France.

FEMS Microbiology Letters
|October 15, 1994
PubMed

Insights

DNA intercalators like actinomycin D and ellipticine, and DAPI, inhibit haloarchaeon growth and bind to its plasmid. These compounds offer a novel method for prescreening DNA intercalators and understanding drug actions in archaea.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Haloarchaea possess unique plasmids, such as pGRB-1 in Halobacterium sp. GRB.
  • Understanding drug interactions with archaeal DNA is crucial for antimicrobial development.
  • DNA topoisomerase II inhibitors are known to affect DNA structure and function.

Purpose of the Study:

  • To investigate the effects of DNA intercalators and a minor groove ligand on haloarchaeal growth and plasmid DNA.
  • To determine if these compounds induce DNA damage or alter supercoiling in Halobacterium sp. GRB.
  • To explore the potential of haloarchaeal plasmids as a tool for drug screening.

Main Methods:

  • Treatment of Halobacterium sp. GRB with actinomycin D, 2-methyl-9-hydroxy-ellipticine, and DAPI.
  • Analysis of plasmid pGRB-1 for double-strand breaks and supercoiling changes.
  • Assessment of growth inhibition in response to drug treatment.

Main Results:

  • Actinomycin D, ellipticine, and DAPI inhibited Halobacterium sp. GRB growth and bound to plasmid pGRB-1.
  • Unlike topoisomerase II inhibitors, these compounds did not cause DNA breaks or relaxation.
  • DNA intercalators inhibited positive supercoiling induced by novobiocin, suggesting transcription-driven supercoiling.

Conclusions:

  • Haloarchaeal plasmids can be used to prescreen for DNA intercalators.
  • The mode of action of different drug families can be discriminated using haloarchaeal plasmids.
  • Transcription likely drives positive supercoiling in haloarchaea, similar to Bacteria.

More Related Videos

Tools to Study the Role of Architectural Protein HMGB1 in the Processing of Helix Distorting, Site-specific DNA Interstrand Crosslinks12:19

Tools to Study the Role of Architectural Protein HMGB1 in the Processing of Helix Distorting, Site-specific DNA Interstrand Crosslinks

Published on: November 10, 2016

CD Spectroscopy to Study DNA-Protein Interactions06:48

CD Spectroscopy to Study DNA-Protein Interactions

Published on: February 10, 2022

Related Concept Videos

DNA Topoisomerases02:02

DNA Topoisomerases

Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types.  Type I...
Drugs that Destabilize Microtubules01:10

Drugs that Destabilize Microtubules

Microtubules are dynamic structures and can be regulated by microtubule targeting agents (MTAs). Microtubule destabilizing drugs are a class of MTAs that destabilize and prevent microtubules' polymerization. Both natural and synthetic chemicals can be found under this class of drugs. Vincristine and vinblastine, two vinca alkaloids, and colchicine were among the first to be discovered. These drugs can affect cells in various ways, either by inducing a change in cell morphology, preventing...
Nucleoid01:24

Nucleoid

The nucleoid represents a structurally and functionally distinct region within prokaryotic cells, where the cell's DNA and associated proteins are housed. Unlike eukaryotic cells, prokaryotes lack a membrane-bound nucleus, and the nucleoid facilitates the organization and accessibility of the genetic material within this constraint. The DNA in most bacteria and archaea exists as a single, circular, double-stranded molecule that is highly compacted through supercoiling and interactions with...
Diversity of Archaea III01:27

Diversity of Archaea III

Crenarchaeota, a prominent phylum of Archaea, is remarkable for its ability to thrive in extreme environments characterized by high temperatures and acidity. These microorganisms inhabit sulfuric hot springs, volcanic systems, and submarine hydrothermal vents, where temperatures often exceed 100°C. The unique adaptations of Crenarchaeota not only allow survival under such extreme conditions but also provide insights into the mechanisms of life in primordial Earth-like environments.Morphological...
Diversity of Archaea IV01:29

Diversity of Archaea IV

Hyperthermophilic archaea are a group of extremophiles thriving at temperatures above 80°C, often in hydrothermal vents and volcanic soils where conditions surpass the boiling point of water. At such temperatures, proteins, membranes, and DNA in most organisms degrade, but hyperthermophiles have evolved remarkable adaptations to maintain stability and function.Unique Cellular FeaturesHyperthermophilic membranes are composed of a monolayer of biphytanyl tetraether lipids, which resist thermal...
Inhibitors of Bacterial DNA Synthesis01:28

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...