Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

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...
Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...
Development of Antibiotic Resistance01:30

Development of Antibiotic Resistance

Antibiotic resistance is a major public health concern that arises when bacteria evolve mechanisms to withstand the effects of antibiotic treatments. This resistance can be intrinsic, acquired through genetic mutations, or transferred between bacteria via horizontal gene transfer. The development of antibiotic resistance poses significant challenges in treating bacterial infections and necessitates ongoing research to develop new therapeutic strategies.Intrinsic resistance occurs when bacterial...
Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...
Gene Regulation in Microbial Communities: Quorum Sensing01:28

Gene Regulation in Microbial Communities: Quorum Sensing

Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...
Antibiotic Selection00:57

Antibiotic Selection

Overview

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Jianpi Huayu decoction suppresses hepatocellular carcinoma invasion and metastasis by inhibiting SIRT5-regulated Nrf2 activation and mitochondrial metabolic reprogramming.

Phytomedicine : international journal of phytotherapy and phytopharmacology·2026
Same author

Quinolone tolerance in <i>Escherichia coli</i> due to defects in the adenosine ribonucleotides <i>de novo</i> biosynthesis pathway.

mLife·2026
Same author

TNF-α alters dedifferentiation of enterochromaffin cells, redirecting toward neuroendocrine tumors.

American journal of physiology. Gastrointestinal and liver physiology·2026
Same author

Editorial: Advancing antibiotic candidates for eradication of persistent bacterial infections.

Frontiers in pharmacology·2026
Same author

CRISPR-Cas-associated SCCmec Variants in Methicillin-resistant Staphylococcus aureus Evade Rapid Diagnostic Detection.

The Journal of infectious diseases·2025
Same author

Jianpi-huayu Decotion regulates TREM1/DAP12 pathway to improve the immunosuppressive tumor microenvironment and enhance the anti-hepatocellular carcinoma effect of PD-1 inhibitors.

Journal of ethnopharmacology·2025

Related Experiment Video

Updated: Jun 20, 2026

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
08:58

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes

Published on: March 3, 2023

Quinolones: action and resistance updated.

Karl Drlica1, Hiroshi Hiasa, Robert Kerns

  • 1Public Health Research Institute, New Jersey Medical School, UMDNJ, 225 Warren Street, Newark, NJ 07103, USA. drlicaka@umdnj.edu

Current Topics in Medicinal Chemistry
|September 15, 2009
PubMed
Summary

Quinolones inhibit bacterial DNA replication by trapping enzymes on DNA, leading to cell death via chromosome fragmentation and reactive oxygen species. Developing new quinolone compounds can help restrict the emergence of drug resistance.

More Related Videos

Visualization of Bacterial Resistance using Fluorescent Antibiotic Probes
08:23

Visualization of Bacterial Resistance using Fluorescent Antibiotic Probes

Published on: March 2, 2020

Quantification of Violacein in Chromobacterium violaceum and Its Inhibition by Bioactive Compounds
07:13

Quantification of Violacein in Chromobacterium violaceum and Its Inhibition by Bioactive Compounds

Published on: August 8, 2025

Related Experiment Videos

Last Updated: Jun 20, 2026

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
08:58

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes

Published on: March 3, 2023

Visualization of Bacterial Resistance using Fluorescent Antibiotic Probes
08:23

Visualization of Bacterial Resistance using Fluorescent Antibiotic Probes

Published on: March 2, 2020

Quantification of Violacein in Chromobacterium violaceum and Its Inhibition by Bioactive Compounds
07:13

Quantification of Violacein in Chromobacterium violaceum and Its Inhibition by Bioactive Compounds

Published on: August 8, 2025

Area of Science:

  • Microbiology
  • Molecular Biology
  • Pharmacology

Background:

  • Quinolones are a class of antibiotics that target bacterial DNA replication.
  • Previous models suggested quinolone binding primarily to helix-4 of GyrA and ParC proteins.
  • Recent crystallography indicates drug intercalation within cleaved DNA, with partial interaction with helix-4.

Purpose of the Study:

  • To elucidate the structural mechanisms of quinolone-enzyme-DNA complex formation.
  • To understand the pathways leading to bacterial cell death upon quinolone treatment.
  • To explore strategies for mitigating the development of quinolone resistance.

Main Methods:

  • X-ray crystallography to determine drug-DNA-enzyme complex structures.
  • Analysis of DNA replication inhibition and bacterial chromosome fragmentation.
  • In vitro and in vivo models to study quinolone resistance development.

Main Results:

  • Quinolones form complexes with DNA gyrase and topoisomerase IV, trapping them on cleaved DNA.
  • Two distinct models of drug binding may represent different stages of complex formation.
  • Chromosome fragmentation, potentially involving reactive oxygen species, contributes to cell death.
  • Stepwise quinolone resistance emerges at drug concentrations between the MIC and MPC.
  • Plasmid-borne resistance mechanisms are increasingly prevalent.

Conclusions:

  • Understanding quinolone-DNA-enzyme interactions is crucial for antibiotic development.
  • Bacterial cell death involves complex fragmentation and oxidative stress pathways.
  • Narrowing the gap between MIC and MPC through compound design is key to limiting resistance.
  • The rise of plasmid-borne resistance necessitates urgent attention.