生物膜(英文版)

Catheter
Morning Glory Pool in Yellowstone National Park
National Park Service
Contact lens
Biofilm formation and growth
O2
• Quorum sensing and chemical signaling • Microcolonies with extracellular matrix • Network of channels • Cells experience different environmental conditions • Multi-species
• Promoter regions • Unstable fluorescent proteins
O2
• Microscopy
What is complexity?
Dr. Adami – Complexity Club, Jan 21, 2003
• “Structural” complexity: Number of different parts and their interactions • “Hierarchical” complexity: Number of levels in a hierarchy • “Functional” complexity:
• “Sequence” complexity
How is a biofilm complex? Microenvironment (chemical signals, nutrient conditions) -> complex regulatory networks -> change in physiology or metabolism -> affects environment • Complex cell-cell interactions • Effects of environmental conditions on biofilm morphology and physiology. Multiple parameters exist and their effects are difficult to predict. • More “complex” than planktonic cells
Biofilm formation and growth
Given the heterogeneity of the environment, how is the biofilm community structured? There is a strong relationship between the cell’s environment and its physiology and structure.
– Number of different functions an organism can perform, or – Computational capacity of an organism (or device), the maximal mutual entropy between input signals and output actions.
Who cares? How is it useful? How might thinking about complexity in biofilms systems be useful? • Adaptation and complexity • Does the complexity of the system allow it to be more adaptable or resilient? • Are there complexity measures that could allow us to predict how resilient a biofilm would be? • Would decreasing the complexity of a biofilm cause it to be more susceptible to environmental influences?
• Complexity in biology, such as functional, structural and hierarchical complexity and some of the implications of complexity in adaptation.
What is a biofilm?
Biofilms form
Nutrient levels decrease towards the center
Variety of environmental niches form Science News
Relationship between biofilm morphology and the environment
.5mM lactate
5mM LB lactate 1:10
50 um
How are biofilms differentiated?
Given the existence of many microenvironments, how is the biofilm organized with respect to metabolism?
biofilm
Complexity
What is complexity? What is a good quantitative measure of complexity?
• No theoretical discussion of complexity.
• Introduction to biofilms
• Important to keep in mind when working with biofilm systems
O2
Shewanella oneidensis strain MR-1
–facultative anaerobe –versatile respiration –gram negative –MR-1 genome is sequenced and can be manipulated genetically
Bacteria that are attached to a surface and form a 3-dimensional structure, held together by an extracellular polymeric substance
Biofilms in the environment
Hale Waihona Puke Baidu Design concept
Use reporter systems consisting of promoter regions fused to fluorescent proteins to indicate regions of differing metabolism within a biofilm Use oxygen respiration as indicators of the cells metabolic state