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Patterns of gene expression in Bacillus subtilis colonies
1Department of Microbiology and Immunology, University of Arizona, Tucson 85721.
Journal of Bacteriology
|August 1, 1993
Summary
Bacillus subtilis gene expression varies with colony density and nutrient availability. High density leads to early, uniform expression, while low density results in late, peripheral expression, influenced by diffusible factors and substrate geometry.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Genetics
Background:
- Bacillus subtilis 5:7 harbors the lacZ reporter gene integrated via Tn917.
- Understanding reporter gene expression provides insights into bacterial gene regulation.
Purpose of the Study:
- To investigate the spatial and temporal regulation of host gene expression in Bacillus subtilis 5:7.
- To identify factors influencing lacZ reporter gene expression patterns.
Main Methods:
- Culturing Bacillus subtilis 5:7 at varying densities on X-Gal indicator plates.
- Observing colony morphology and lacZ expression patterns.
- Analyzing gene expression in response to different growth conditions and substrate geometries.
Main Results:
- High plating density resulted in small colonies with early, uniform lacZ expression.
- Low plating density yielded large colonies with late, peripheral lacZ expression.
- Gene expression was influenced by nutrient depletion, spatial-temporal factors, and substrate geometry, suggesting response to concentration gradients.
Conclusions:
- Bacillus subtilis gene expression is dynamically regulated by colony density and environmental cues.
- Nutrient availability and physical growth constraints significantly impact bacterial gene expression patterns.
- The lacZ reporter system effectively visualizes complex spatial and temporal gene regulation in bacterial colonies.