An alternative resource allocation strategy in the chemolithoautotrophic archaeon Methanococcus maripaludis

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 118; no. 16; pp. 1 - 8
• Main Authors: Müller, Albert L., Gu, Wenyu, Patsalo, Vadim, Deutzmann, Jörg S., Williamson, James R., Spormann, Alfred M.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 20-04-2021
• Subjects: Bacteria; Biological Sciences; Biomass energy production; Cell culture; Cell size; Continuous culture; Deoxyribonucleic acid; Dilution; DNA; E coli; Energy limitation; Energy metabolism; Growth rate; Invariants; Maintenance; Methanococcus maripaludis; Methanogenesis; Microorganisms; Nutrient content; Protein biosynthesis; Protein synthesis; Proteins; Proteomes; Resource allocation; Ribosomes; proteome allocation; slow growth; maintenance energy; methanogen; ribosome activity
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2025854118

Most microorganisms in nature spend the majority of time in a state of slow or zero growth and slow metabolism under limited energy or nutrient flux rather than growing at maximum rates. Yet, most of our knowledge has been derived from studies on fast-growing bacteria. Here, we systematically characterized the physiology of the methanogenic archaeon Methanococcus maripaludis during slow growth. M. maripaludis was grown in continuous culture under energy (formate)-limiting conditions at different dilution rates ranging from 0.09 to 0.002 h−1, the latter corresponding to 1% of its maximum growth rate under laboratory conditions (0.23 h−1). While the specific rate of methanogenesis correlated with growth rate as expected, the fraction of cellular energy used for maintenance increased and the maintenance energy per biomass decreased at slower growth. Notably, proteome allocation between catabolic and anabolic pathways was invariant with growth rate. Unexpectedly, cells maintained their maximum methanogenesis capacity over a wide range of growth rates, except for the lowest rates tested. Cell size, cellular DNA, RNA, and protein content as well as ribosome numbers also were largely invariant with growth rate. A reduced protein synthesis rate during slow growth was achieved by a reduction in ribosome activity rather than via the number of cellular ribosomes. Our data revealed a resource allocation strategy of a methanogenic archaeon during energy limitation that is fundamentally different from commonly studied versatile chemoheterotrophic bacteria such as E. coli.