Upload
edmund-stephens
View
218
Download
1
Embed Size (px)
Citation preview
Bacterial Populations as Multicellular Organisms
Kathy Lee
INTRODUCTION
•1998 … Scientific American – “Bacteria as Multicellular Organisms”
•Multicellularity- only considered a specialized adaptive strategy
•Today
CORE CONCEPTS OF BACTERIAL MULTICELLULARITY
1.Communication and
decision-making capabilities 2.Examples of communication
and behaviors3.Derive adaptive benefits
INTERCELLULAR COMMUNICATION
•Diverse Classes of Signal Molecules –AHL signaling–Oligopeptides
•Differences between AHL signaling and Oligopeptides
•Not all the small diffusible molecules are signals
•Highly diversified chemical structures
Signal Response Systems: Interpreting Chemical Messages in an Informationally Rich Environment•Each cell can make an appropriate
decision and adjust its activity•Myxobacteria and Bacillus – two
good examples of complex signal-processing networks
•Complexities will prove to be typical
COORDINATED MULTICELLULAR BEHAVIORS – A GENERAL BACTERIAL TRAIT
•Bacteria differentiate biochemically and morphologically and their interactions
•Colony development and collective motility phenomena in bacteria
–E.coli Colony Development•Cell-cell interactions occur after the first cell division
–B. subtilis Colony Development –Proteus and Serratia Swarming
•“Swarming” is the process of rapid migration over a surface
–Granule Development in Anaerobic Bioreactors •Microbial Consortia
ADAPTIVE BENEFITS FROM MULTICELLULAR COOPERATION
•More efficient proliferation from cellular division
•Access to resources and niches that require a critical mass and cannot effectively be utilized by isolated cells
•Collective defense against antagonists that eliminate isolated cells
Optimization of population survival by differentiation into distinct cell types
•Sporulation and Formation of Dormant Cells
•Exchange of Genetic Information
•Mutation
CONCLUSION
•Bacterial multicellularity deepens our appreciation of the information-processing capabilities of individual bacterial cells.