Related Experiment Video

Updated: Aug 6, 2026

Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance
09:00

Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance

Published on: May 2, 2018

The mar regulon: multiple resistance to antibiotics and other toxic chemicals

M N Alekshun1, S B Levy

  • 1Center for Adaptation Genetics and Drug Resistance, Dept of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA.

Trends in Microbiology
|September 28, 1999
PubMed

Insights

The multiple antibiotic resistance (mar) locus in E. coli confers resistance to various toxic substances. Exposure to aromatic compounds triggers this Mar phenotype, impacting bacterial defense mechanisms.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • The multiple antibiotic resistance (mar) locus is a key genetic element in *Escherichia coli* and related bacteria.
  • This locus regulates resistance to a wide array of compounds, not limited to antibiotics.

Purpose of the Study:

  • To investigate the function of the *mar* locus in controlling resistance to diverse toxic chemicals.
  • To understand the induction mechanism of the Mar phenotype.

Main Methods:

  • Utilizing *Escherichia coli* as a model organism.
  • Phenotypic analysis of resistance profiles.
  • Exposure studies with various chemical agents.

Main Results:

  • The *mar* locus mediates resistance to structurally unrelated compounds like antibiotics, disinfectants, and solvents.
  • The Mar phenotype is induced by exposure to chemicals containing aromatic rings.

Conclusions:

  • The *mar* locus plays a crucial role in the general stress response of Enterobacteriaceae.
  • Aromatic compounds are potent inducers of broad-spectrum resistance in bacteria.

More Related Videos

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues07:10

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues

Published on: February 19, 2019

Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes08:58

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

Published on: March 3, 2023

Related Concept Videos

Global Regulatory Systems01:28

Global Regulatory Systems

Global regulatory systems in bacteria enable rapid and coordinated responses to environmental changes by integrating sensory inputs with gene expression, ensuring efficient adaptation to fluctuating conditions. Key global regulatory mechanisms include regulons, two-component systems, sigma factors, and secondary messengers.Regulons and Global RegulatorsA regulon is a collection of genes and operons controlled by a common global regulator. These regulators enable bacteria to prioritize resource...
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,...
Stringent Response in E. coli01:23

Stringent Response in E. coli

Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
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...
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...
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...