Microbial Life in a Winogradsky Column: From Lab Course to Diverse Research Experience

Abstract

Many traditional lab courses include both standard and inquiry-based experiments, yet lack cooperative and authentic lab experiences. Such experiences are important for microbiology students and burgeoning researchers. In a novel lab environment, students constructed Winogradsky columns using common soil and water sources. During initial column incubation, students learned methods for identification of microbial isolates including staining, microscopy, biochemistry and 16S-rRNA sequencing. Concurrently, students challenged their columns via varied substrates and contaminants including enrichment with nitro-compounds, hydrocarbons, acids and other environmental stressors. Students were encouraged to use both basic and more advanced identification methods to study the effect of such challenges within their columns. The students were required to maintain lab notebooks and attend weekly lab meetings, which were designed to share progress and facilitate experimentation among their lab-mates. At the end of the semester, students gathered to present their data and conclusions. By engaging in weekly meetings and a final conference, students were able to construct a snapshot of the microbial diversity, including phylogeny and metabolism, in the soil and water used to construct the Winogradsky columns. By using a common source, students were able to observe an array of diversity within individual columns and extrapolate towards the tremendous microbial diversity in the initial soil and water samples. Equally important to the data obtained, the students engaged in a collaborative effort through discussion, trouble-shooting, weekly meetings and the summative conference. Such efforts enabled students to participate in an authentic research experience within a traditional undergraduate laboratory course. Editor's Note: The ASM advocates that students must successfully demonstrate the ability to explain and practice safe laboratory techniques. For more information, read the laboratory safety section of the ASM Curriculum Recommendations: Introductory Course in Microbiology and the Guidelines for Biosafety in Teaching Laboratories, available at www.asm.org. The Editors of JMBE recommend that adopters of the protocols included in this article follow a minimum of Biosafety Level 2 practices.