A laboratory is testing various compounds with antibiotic properties. For studies using cultures of the bacterium Escherichia coli growing exponentially with a generation time of 30 minutes. The lab is interested in the type of bacteriostatic effect and where the antibiotic acts in the cell. To do this, add the various radiolabelled antibiotic molecules with carbon-14 and leave on for an hour. Below are the results when looking at cells under a microscope for phase contrast, DAPI fluorescence staining, and by microscopic autoradiography indicates where the radioactivity is localized within the cell. The control uses a crop that does not add any antibiotic.
Antibiotics used were: mecillinan, nalidixic acid and polymyxin
explain the mechanism of action of each antibiotic
(Note: This issue was included in the 1 st Part of the course Environmental Microbiology 2008-9 course so have exaggerated the actual effects of antibiotics in the pictures above)
