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Nutritional Effects on the Growth, Cell Size, and Resistance to Stress of Acholeplasma laidlawii
Martha Folmsbee1, Courtney Noah, Morven McAlister
1Pall Corporation.
Abstract:
Due to their lack of a cell wall, mycoplasmas are useful models for the study of biological membranes. However, they are much less appreciated by cell culture laboratories due to their unfortunate tendency to contaminate cell culture lines (1-5). One of the primary protections of a cell line is through filtration of cell culture media. It is necessary to use 0.1 μm-rated filters because mycoplasmas can often penetrate the more commonly used 0.2 (or 0.22) μm-rated filters. In the battle against mycoplasma contamination, it is helpful to delineate factors that may affect mycoplasma replication, cell size, and resistance to contamination control. The addition of cholesterol and unsaturated long chain fatty acids to growth media enhance replication of Acholeplasma laidlawii (6-10). The absence of glucose, presence of unsaturated fatty acids, increased incubation period, and exposure to stress promote the production of small mycoplasma cells (6-12). Exposure to a high salt concentration, hydrogen peroxide, and UV light, which are commonly used for contamination control, can enhance the production of small resistant cells (13-15).
Insights
Mycoplasmas, lacking cell walls, are key for membrane studies but often contaminate cell cultures. Understanding factors like media composition and stress is crucial for controlling mycoplasma contamination and preventing the emergence of resistant strains.
Area of Science:
- Microbiology
- Cell Biology
- Membrane Biology
Background:
- Mycoplasmas are valuable models for studying biological membranes due to their unique cell wall-deficient structure.
- Despite their utility, mycoplasmas are notorious contaminants in cell culture, posing significant challenges to laboratories.
- Standard cell culture media filtration (0.2 µm) is often insufficient to remove mycoplasmas, necessitating 0.1 µm filters.
Purpose of the Study:
- To identify factors influencing mycoplasma replication, cell size, and resistance to contamination control methods.
- To provide insights for developing more effective strategies against mycoplasma contamination in cell cultures.
Main Methods:
- Review of literature on mycoplasma growth conditions and responses to environmental stressors.
- Analysis of factors affecting mycoplasma replication, including media components like cholesterol and fatty acids.
- Investigation into conditions promoting the formation of small, resistant mycoplasma cells, such as nutrient deprivation and stress exposure.
Main Results:
- Supplementation of growth media with cholesterol and unsaturated fatty acids enhances Acholeplasma laidlawii replication.
- Mycoplasma cell size is reduced by glucose absence, unsaturated fatty acids, extended incubation, and stress.
- Exposure to high salt, hydrogen peroxide, and UV light induces the production of small, resistant mycoplasma cells.
Conclusions:
- Specific growth conditions and stress factors significantly impact mycoplasma characteristics, including size and resistance.
- Understanding these factors is critical for effective mycoplasma contamination control in cell culture environments.
- Mycoplasmas can adapt to common contamination control measures, highlighting the need for vigilant monitoring and advanced filtration techniques.
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