OBSERVATION OF THE ACTION OF PENICILLIN ON BACILLUS-SUBTILIS USING ATOMIC-FORCE MICROSCOPY - TECHNIQUE FOR THE PREPARATION OF BACTERIA

Atomic force microscopy (AFM) is a very convenient means of studying hard and flat samples with atomic resolution. Biological objects, usually soft and rough, are sometimes difficult to image using this technique. Bacteria, which are too small to be observed with good resolution using the optical microscope, are hard enough to be observed with an atomic force microscope at a level of magnification similar to that obtained with the electron microscope. These microorganisms can be prepared for AFM imaging using very rapid and simple techniques. We discuss here different preparation methods and substrates that can be used for the preparation of bacterial samples for observation with AFM. We also show images of different species of bacteria, such as Escherichia coli, and Bacillus subtilis, taken with the atomic force microscope in constant force and constant height modes, as well as images demonstrating the action of penicillin on B. subtilis.