Balance between asymmetric allocation and repair of somatic damage in unicellular life forms as an ancient form of r/K selection

• 成果类型: Article
• 署名作者: Biba, Dmitry A.; Wolf, Yuri I.; Koonin, Eugene V.; Rochman, Nash D.
• 署名单位: National Institutes of Health (NIH) - USA; NIH National Library of Medicine (NLM); Oak Ridge Associated Universities; United States Department of Energy (DOE); Oak Ridge Institute for Science & Education; City University of New York (CUNY) System; City University of New York (CUNY) System
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13474
• DOI: 10.1073/pnas.2400008121/-/DCSupplemental
• 发表日期: 2024-05-28
• 关键词: protein damage; segregation; inheritance; aggregation; death; senescence; bacteria; GROWTH

摘要

Over the course of multiple divisions, cells accumulate diverse nongenetic, somatic damage including misfolded and aggregated proteins and cell wall defects. If the rate of damage accumulation exceeds the rate of dilution through cell growth, a dedicated mitigation strategy is required to prevent eventual population collapse. Strategies for somatic damage control can be divided into two categories, asymmetric allocation and repair, which are not, in principle, mutually exclusive. We explore a mathematical model to identify the optimal strategy, maximizing the total cell number, over a wide range of environmental and physiological conditions. The optimal strategy is primarily determined by extrinsic, damage - independent mortality and the physiological model for damage accumulation that can be either independent (linear) or increasing (exponential) with respect to the prior accumulated damage. Under the linear regime, the optimal strategy is either exclusively repair or asymmetric allocation, whereas under the exponential regime, the optimal strategy is a combination of asymmetry and repair. Repair is preferred when extrinsic mortality is low, whereas at high extrinsic mortality, asymmetric damage allocation becomes the strategy of choice. We hypothesize that at an early stage of life evolution, optimization over repair and asymmetric allocation of somatic damage gave rise to r and K selection strategists.