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Environmental Research Institute (ERI) Seminar Series: "The inflection point hypothesis: The relationship between the temperature dependence of enzyme catalyzed reaction rates and microbial growth rates"

Date Wednesday 14 October 2020
Time 12pm - 1pm
Where S.1.02. Also accessible via Zoom: https://waikato.zoom.us/j/92090192079
Presenter Dr Erica Prentice (University of Waikato)
Contact Fiona Martin
Contact email fmartin@waikato.ac.nz
Admission Cost Free

Abstract:

Biological rates at different scales (from individual enzymes, to microorganism growth rates, to ecosystem processes such as soil respiration and photosynthesis) all display similar curved responses to temperature. The precise relationship between the temperature dependence of enzyme rates and those at larger scales is not well understood. Macromolecular rate theory (MMRT) has been developed and applied to the temperature dependence of biological processes across these scales. In this seminar, I will discuss the work we have done to validate the scaling relationship by investigating the temperature dependence of rates at both the molecular scale (constituent enzymes) and for growth of the parent organism. This work has demonstrated that the inflection point (Tinf) for the temperature dependence of individual metabolic enzymes coincides with the optimal growth temperature for the parent organism. We rationalize this concordance in terms of the necessity for linearly correlated rates for metabolic enzymes over fluctuating environmental temperatures to maintain homeostasis. At temperatures where rates become uncorrelated, we postulate a regulatory catastrophe and organism growth rates precipitously decline at temperatures where this occurs.