Microorganism Lab Report

Microbiology lab serves to teach students basic knowledge of concepts, techniques, and tests used by scientists in the laboratories. Thus far, various methods have been learned to identify and distinguish between microorganisms.The purpose of this exercise is to logically outline a plan using techniques and examinations (learned throughout the semester), critical thinking, and application of that knowledge to identify an unknown bacterium from a mixed culture. This report covers the logical progression used to identify Unknown 15, the isolated microorganism. Handling of microorganisms in the lab requires the use of aseptic technique to establish pure cultures and to protect against environmental contamination. Pure culture contains a single

Thus, for eukaryotes, the biological species concept defines what a species is; a species as a group of organisms that reproduce by interbreeding (3). The biological species concept is limited to organisms that reproduce via sexual reproduction (or the passing of traits from parent to offspring) and within the same species (3). Prokaryotes cannot be defined within the guidelines of the biological species concept, because they participate in horizontal gene transfer, have highly heterogenous genomes, do not participate in sexual reproduction, and are difficult to cultivate in pure culture (3). Horizontal gene transfer (transformation, transduction, and conjugation) is the unidirectional movement of information between unrelated organisms that clouds the distinction between species

Through 16S rRNA gene sequencing molecular sequences are analyzed and compared to a database of sequences (4). Ribosomal RNA is found throughout all domains of life (1). 16S rRNA gene sequencing is especially beneficial, because it makes it faster and easier to determine if DNA-DNA hybridization needs to be done (3). If an organism is less than 97% similar to another organism, then it can be classified as a unique species without the use of DNA-DNA hybridization (3). Horizontal gene transfer assisted in shaping the bacterial species concept by demonstrating the shortcomings of the biological species concepts as a means to classify bacterial species; it has been publicized that horizontal gene transfer makes it nearly impossible to understand microbial evolution