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Effect of dihydrostreptomycin on active transport in isolated bacterial membrane vesicles
Abstract:
Membrane vesicles prepared from bacterial cells grown in the absence of dihydrostreptomycin but subsequently incubated in the presence of dihydrostreptomycin transported proline normally, but vesicles prepared from cells grown in media to which dihydrostreptomycin was added 30 min before harvesting had a greatly impaired ability to accumulate proline. The latter cells extruded protons normally but were unable to maintain a proton gradient as effectively as normal cells. These data indicated that metabolism was required for dihydrostreptomycin to exert an effect on the bacterial cell membrane.
Insights
Dihydrostreptomycin impairs bacterial proline transport by affecting the cell membrane proton gradient. This effect requires bacterial metabolism, highlighting its role in drug-induced membrane changes.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Bacterial cell membranes are crucial for nutrient transport and maintaining cellular homeostasis.
- Dihydrostreptomycin is an antibiotic that can affect bacterial physiology.
Purpose of the Study:
- To investigate the impact of dihydrostreptomycin on bacterial membrane function, specifically proline transport.
- To determine the role of bacterial metabolism in dihydrostreptomycin's effect on membrane properties.
Main Methods:
- Preparation of bacterial membrane vesicles.
- Assessing proline transport and proton extrusion in vesicles.
- Comparing vesicle function from cells with and without dihydrostreptomycin exposure.
Main Results:
- Membrane vesicles from cells incubated with dihydrostreptomycin showed normal proline transport.
- Vesicles from cells grown with dihydrostreptomycin prior to harvesting exhibited impaired proline accumulation.
- These affected cells extruded protons but failed to maintain an effective proton gradient.
Conclusions:
- Dihydrostreptomycin significantly impairs bacterial proline transport by disrupting the proton gradient across the cell membrane.
- Bacterial metabolism is essential for dihydrostreptomycin to exert its inhibitory effect on membrane function.
- These findings suggest a metabolic-dependent mechanism for dihydrostreptomycin-induced membrane alterations.