Related Experiment Videos
[Genotypic and phenotypic characteristics of L-line cells resistant to ethidium bromide]
Abstract:
Stable mutants resistant to ethidium bromide in concentrations of 1 and 3 micrograms/ml have been selected in a single step in L cells. The frequency of spontaneously occurring ethidium bromide resistant clones after the exposure to 1 microgram/ml of the drug has been established as 5.10(-5). Resistant variants were induced following treatment with mutagen N-methyl-N-nitro-N-nitrosoguanidine. The resistant clones were shown to be resistant to higher concentration of the agent then which was used for selection. In multistep selection, a number of clones resistant to ethidium bromide in concentration up to 50 micrograms/ml was obtained. The alteration in the permeability of plasma membrane to the drug is the clue mechanism of the resistance.
Insights
Researchers developed ethidium bromide resistant L cells. This resistance, linked to altered cell membrane permeability, was achieved through single-step and multi-step selection methods, and mutagenic induction.
Area of Science:
- Cell Biology
- Genetics
- Biochemistry
Background:
- Ethidium bromide is a mutagenic intercalating agent.
- Drug resistance in cell lines is a crucial area of study for understanding cellular defense mechanisms.
- Investigating resistance mechanisms can reveal insights into cellular transport and membrane function.
Purpose of the Study:
- To select and characterize stable ethidium bromide resistant L cell mutants.
- To determine the frequency of spontaneous ethidium bromide resistance.
- To investigate the mechanism underlying ethidium bromide resistance.
Main Methods:
- Single-step and multi-step selection of L cells using increasing concentrations of ethidium bromide.
- Induction of resistance using the mutagen N-methyl-N-nitro-N-nitrosoguanidine.
- Assessment of resistance levels and investigation of plasma membrane permeability changes.
Main Results:
- Stable ethidium bromide resistant L cell mutants were successfully selected.
- The frequency of spontaneous resistance at 1 microgram/ml ethidium bromide was determined to be 5 x 10^-5.
- Mutagenesis significantly increased the induction of resistant variants.
- Resistant clones exhibited resistance to concentrations far exceeding the initial selection levels.
- Multistep selection yielded clones resistant up to 50 micrograms/ml ethidium bromide.
- Altered plasma membrane permeability to ethidium bromide was identified as the primary resistance mechanism.
Conclusions:
- Ethidium bromide resistance in L cells can be efficiently induced and selected.
- Plasma membrane permeability alterations are the key mechanism conferring resistance to ethidium bromide.
- This study provides a model for generating and studying drug-resistant cell lines, with implications for understanding drug transport and cellular adaptation.