Cell division in most bacteria is a highly organized, regular process in which a single cell gives rise to two essentially equivalent daughter cells. Division is coordinated with parent cell growth and DNA replication and dependent upon cell wall synthesis. Mycoplasma is a genus of very small bacteria resulting from reductive evolution of the genome, leaving them with some of the most minimal naturally occurring genomes known. Mycoplasmas lack some characteristic features of other bacteria, including the cell wall, making them difficult to culture. We predicted the absence of a cell wall would affect the division of mycoplasma cells, which has not been investigated systematically, making their division an unusual process compared to other bacteria. We used a light microscope to capture sequential images of live mycoplasma cells over the course of 2 hours to observe patterns of changes in cell shape associated with cell division. We focused on Mycoplasma odobenus, isolated from a walrus, and Mycoplasma hyorhinis, a pig pathogen. We found division of these species is characterized by transformations in cell shape consistent with irregular division events, especially for M. odobenus, which grows and divides rapidly compared to most mycoplasma species. We conclude in the absence of a cell wall, mycoplasmas must tolerate irregular divisions. Future studies will address DNA replication during these unusual divisions and the relationship between the growth rate and division.
Author(s): Hannah Latimer, Microbiology Major
Advisor(s): Mitchell Balish, Department of Microbiology
You must be logged in to post a comment.