Resource Allocation in Slow Growing Methanogenic Archaea
Abstract
Slow or non-growing microbes affect several key aspects of our life, including wastewater treatment and bioremediation, microbial activities in marine deep sea sediments, and chronic persistent infections. The core intellectual challenge of the biology of ÔLife in the slow laneÕ is to understand how, under slow growth conditions, cells allocate cellular resources in form of energy, electron, and carbon, and how cells coordinate key physiological processes such as catabolism and anabolism. Early studies on macromolecular synthesis in microbes, in particular in E. coli, provided a wealth of molecular insights into processes during exponential growth, typically determined in batch cultures at maximum growth rate. Only very recently, relevant insights on systems-level physiology were obtained based on experiments with E. coli grown at different growth rates using glucose as sole catabolic and anabolic source. Despite those new fundamental insights, E. coli does not represent the majority of slow growing, niche-adapted microorganisms found in Nature. Therefore, we propose to conduct systems-level molecular studies on the physiology of slow growth with methanogenic Archaea. We will conduct experiments in anaerobic chemostats, operated at various dilution rates equivalent to doubling times of up to 12 days. Growth rates will be limited by either catabolic or anabolic substrates, and extrinsic and intrinsic perturbations will be imposed to catabolic or anabolic limitations at selected growth rates. Key parameters that will be determined include, but are not limited to, cell size, growth yield, ribosome number per cell, number of occupied and unoccupied ribosomes, DNA content, as well as the specific rate of methane formation and the proteome composition (catabolic and anabolic). The data will be integrated to answer key questions of slow growth, including: How is cellular energy allocated during slow growth; how do slow growing cells accommodate a smaller anabolic and catabolic proteome; is the cellular ribosome level constant or variable, and does the fraction of active ribosomes vary with growth rate and perturbation; Is metabolism (catabolism) uncoupled from growth at low growth rates?
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 09, 2020
- Source ID
- W911NF2010111
Entities
People
- Alfred M Spormann
Organizations
- Army Contracting Command
- Stanford University
- United States Army