Phenotypic Characterization and the Principles of Comparative Systematics

Abstract

In performing phenotypic characterization tests, the organisms used for the inoculation of test media should be from fresh transfers and in good physiological condition. The methods described in this chapter are based primarily on methods developed for the characterization and identification of organisms which have usually been isolated on nutrient-rich media. While zoologists may be content to classify all insects or all vertebrates, prokaryote systematics generally deals with all prokaryotes and in an evolutionary context attempts to extend this study back to the origin of life itself. To test for acetamide hydrolysis, streak the surface of an acetamide agar slant with a sample from a dilute suspension. Incubate for up to 7 days. Care should be taken to ensure that the basal medium to which the carbohydrates are added does not contain fermentable or oxidizable sugars, and control media without any added carbohydrates should always be included during testing of cultures. Methanogenic members of the Archaea also fluoresce under UV light. Some facultative anaerobes, such as Escherichia coli and Staphylococcus aureus, grow aerobically by respiration with oxygen and grow anaerobically by fermentation.