Microautoradiography: recent advances within the studies of the ecophysiology of bacteria in biofilms

Microautoradiography (MAR) is a technique that allows the direct identification of active microorganisms and of their metabolic capabilities without prior enrichment or cultivation. Today, this technique is probably the only one that allows an in-depth investigation of the ecophysiology of uncultivated bacteria under their natural conditions, and it possesses, therefore, alone or in combination with other in situ techniques, a great potential to be used in comprehensive studies of biofilms and other ecosystems. Here, we present a brief description of the microautoradiographic technique, and recent examples of the type of information that can be obtained using MAR in combination with FISH or with other methods when investigating biofilm processes. Also, some limitations of the technique are discussed.