Related Experiment Video

Updated: Aug 18, 2026

Visualization of UV-induced Replication Intermediates in E. coli using Two-dimensional Agarose-gel Analysis
10:36

Visualization of UV-induced Replication Intermediates in E. coli using Two-dimensional Agarose-gel Analysis

Published on: December 21, 2010

Sulphydryl-mediated DNA breakage by phlemomycin in Escherichia coli

M J Sleigh, G W Grigg

    Mutation Research
    |February 1, 1977
    PubMed

    Insights

    Phleomycin antibiotic causes DNA damage in E. coli primarily through sulphydryl-mediated breakage. This process is influenced by intracellular sulphydryl levels and can be inhibited by specific agents.

    Area of Science:

    • Microbiology
    • Molecular Biology
    • Biochemistry

    Background:

    • Phleomycin is an antibiotic known to induce DNA breakage.
    • The precise mechanism of phleomycin-induced DNA damage in bacteria, particularly Escherichia coli, requires further elucidation.

    Purpose of the Study:

    • To investigate the role of sulphydryl groups in phleomycin-induced DNA damage in Escherichia coli.
    • To identify factors influencing the sensitivity of E. coli to phleomycin.

    Main Methods:

    • Assessing DNA breakage in E. coli exposed to phleomycin.
    • Evaluating the effects of chelating agents, sulphydryl blocking agents, and antioxidants on phleomycin activity.
    • Analyzing the response to phleomycin in bacterial mutants with altered glutathione synthesis.
    • Utilizing spheroplasts to study phleomycin effects in genetically modified bacteria.

    Main Results:

    • Sulphydryl-mediated breakage is a significant contributor to phleomycin-induced DNA damage in E. coli.
    • Phleomycin's effects were inhibited by chelating agents, sulphydryl blocking agents, and antioxidants.
    • Increased intracellular free sulphydryl levels enhanced the response to phleomycin.
    • Mutants deficient in glutathione synthesis exhibited reduced DNA breakage, especially at lower phleomycin concentrations.
    • Dithiothreitol restored phleomycin responsiveness in specific mutant spheroplasts.

    Conclusions:

    • Sulphydryl-mediated breakage is the principal mechanism of DNA damage by phleomycin in E. coli.
    • Intracellular sulphydryl levels play a crucial role in modulating bacterial sensitivity to phleomycin.
    • The findings provide insights into the biochemical pathways involved in antibiotic-induced DNA damage.

    More Related Videos

    Inducing a Site Specific Replication Blockage in E. coli Using a Fluorescent Repressor Operator System11:19

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

    Published on: August 21, 2016

    Characterizing DNA Repair Processes at Transient and Long-lasting Double-strand DNA Breaks by Immunofluorescence Microscopy08:31

    Characterizing DNA Repair Processes at Transient and Long-lasting Double-strand DNA Breaks by Immunofluorescence Microscopy

    Published on: June 8, 2018

    Related Concept Videos

    Nucleotide Excision Repair01:08

    Nucleotide Excision Repair

    Overview
    Fixing Double-strand Breaks02:04

    Fixing Double-strand Breaks

    The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
    Single-Strand DNA Binding Proteins01:03

    Single-Strand DNA Binding Proteins

    For successful DNA replication, the unwinding of double-stranded DNA must be accompanied by stabilization and protection of the separated single strands of the DNA. This crucial task is performed by single-strand DNA-binding (SSB) proteins. They bind to the DNA in a sequence-independent manner, which means that the nitrogenous bases of the DNA need not be present in a specific order for binding of SSB proteins to it. The binding of SSB proteins straightens single-stranded DNA (ssDNA) and makes...
    Nucleotide Excision Repair01:38

    Nucleotide Excision Repair

    DNA Distortion and Damage
    Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
    Mismatch Repair01:20

    Mismatch Repair

    Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the new strand and replacing the erroneous bases with correct nucleotides. Mismatch repair is coordinated by many proteins in both prokaryotes and eukaryotes.
    The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
    The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
    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...