Enzyme regulation and mutation in a model serial-dilution ecosystem.

Area of Science:

• Microbial Ecology
• Evolutionary Biology
• Theoretical Ecology

Background:

• Microbial communities exhibit vast diversity, crucial for ecological and medical outcomes.
• Current models struggle to explain microbial diversity beyond resource availability.
• The role of microbial adaptation and evolution in maintaining diversity is under-explored.

Purpose of the Study:

• To investigate how microbial adaptation and evolution influence community diversity.
• To explore the impact of changing growth properties on microbial diversity dynamics.
• To differentiate the effects of ecological adaptation versus evolutionary change on diversity.

Main Methods:

• Expanded a mathematical model of microbial diversity in fluctuating environments.
• Incorporated changes in growth strategy via enzyme regulation (ecological timescale).
• Incorporated changes in growth strategy via mutations (evolutionary timescale).
• Utilized a serial-dilutions framework to analyze community dynamics.

Main Results:

• Enzyme regulation can lead to diversity collapse over extended periods.
• Mutations promoting a 'rich-get-poorer' dynamic enhance microbial diversity.
• Ecological adaptation and evolutionary processes have contrasting effects on diversity.

Conclusions:

• Microbial adaptation and evolution present conflicting mechanisms affecting community diversity.
• Enzyme regulation and mutation-driven evolution have distinct impacts on microbial diversity.
• The study highlights the complex interplay between microbial responses and ecosystem diversity.