Title Evaluation of the Cell Growth of Mycobacteria Using Mycobacterium smegmatis mc2 155 as a Representative Species
Author Jorge A. Gonzalez-y-Merchand1*, Ruben Zaragoza-Contreras1, Rosalina Guadarrama-Medina1, Addy C. Helguera-Repetto1, Sandra Rivera-Gutierrez1, Jorge F. Cerna-Cortes1, Leopoldo Santos-Argumedo2, and Robert A. Cox3
Address 1Departamento de Microbiologia, Escuela Nacional de Ciencias Biologicas, IPN, Prolong. Carpio y Plan de Ayala s/n, Col. Casco de Santo Tomas, Mexico, D.F. 11340, Mexico, 2Departamento de Biomedicina Molecular, CINVESTAV, Zacatenco, Mexico, D.F., Mexico, 3Division of Mycobacterial Research, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
Bibliography Journal of Microbiology, 50(3),419-425, 2012,
Key Words mycobacterial growth, mycobacterial physiology, Mycobacterium smegmatis, flow cytometry
Abstract The study of the in vitro cell growth of mycobacteria still remains a fastidious, difficult, and time-consuming procedure. In addition, assessing mycobacterial growth in the laboratory is often complicated by cell aggregation and slow growth-rate. We now report that the use of a stainless steel spring in the culture led to an absence of large cell clumps, to a decrease of dead cells in the exponential phase and to growth of a more homogeneous population of large cells. We also report that flow cytometry is a rapid, simple and reliable approach to monitor mycobacterial cell growth and viability. Here, we monitored Mycobacterium smegmatis cellular growth by optical density, dry cell mass, and colony forming units; in addition, viability, cell size and granularity profiles were analyzed by flow cytometry, and cell morphology by electron microscopy. Cultures monitored by flow cytometry may lead to a better understanding of the physiology of mycobacteria. Moreover, this methodology may aid in characterizing the cell growth of other fastidious species of microorganisms.