This exercise is designed to expose students to a group of microorganisms that are often omitted from standard Microbiology laboratories. In addition it incorporates a research component into the curriculum to stimulate enthusiasm for the process of scientific discovery.  The component parts of this exercise should integrate well into standard lab syllabi by utilizing techniques that are routinely taught in most introductory Microbiology lab curricula.
    Students collect and dry soil samples from diverse locations. They isolate pure cultures of Actinomycetes from the soil by serial dilution and spread plating. Slide cultures are performed to demonstrate the morphological characteristics of these filamentous bacteria. The isolates are screened for antibiotic production by placing plugs of agar cut from streak plate cultures onto Kirby Bauer Antibiotic Assay plates. About one fourth of the isolates produce detectable antibiotics with inhibition zone diameters comparable to those produced by commercial antibiotic disks. Sephadex or ion exchange chromatography of the supernatant from liquid cultures of the Actinomycetes strains is performed in 1 cc syringe columns. The profile of separated antimetabolites is determined by directly collecting the eluted fractions onto filter disks which are applied to Kirby Bauer Assay plates.