Limits...
The Biokinetic Spectrum for Temperature.

Corkrey R, McMeekin TA, Bowman JP, Ratkowsky DA, Olley J, Ross T - PLoS ONE (2016)

Bottom Line: We found another peak at 67°C and a steady decline in maximum rates thereafter.We used a thermodynamic model to recover the Δ-shape, suggesting that the growth rate limits arise from a trade-off between activity and stability of proteins.The spectrum provides underpinning principles that will find utility in models concerned with the thermal responses of biological processes.

View Article: PubMed Central - PubMed

Affiliation: Tasmanian Institute of Agriculture / School of Land and Food, University of Tasmania, Hobart, Tasmania, Australia.

ABSTRACT
We identify and describe the distribution of temperature-dependent specific growth rates for life on Earth, which we term the biokinetic spectrum for temperature. The spectrum has the potential to provide for more robust modeling in thermal ecology since any conclusions derived from it will be based on observed data rather than using theoretical assumptions. It may also provide constraints for systems biology model predictions and provide insights in physiology. The spectrum has a Δ-shape with a sharp peak at around 42°C. At higher temperatures up to 60°C there was a gap of attenuated growth rates. We found another peak at 67°C and a steady decline in maximum rates thereafter. By using Bayesian quantile regression to summarise and explore the data we were able to conclude that the gap represented an actual biological transition between mesophiles and thermophiles that we term the Mesophile-Thermophile Gap (MTG). We have not identified any organism that grows above the maximum rate of the spectrum. We used a thermodynamic model to recover the Δ-shape, suggesting that the growth rate limits arise from a trade-off between activity and stability of proteins. The spectrum provides underpinning principles that will find utility in models concerned with the thermal responses of biological processes.

No MeSH data available.


Related in: MedlinePlus

Thermodynamic parameters trends.Trends in the mean thermodynamic parameters (, ΔCP and n) for strains above (solid lines) and below (dashed lines) quantile curves versus temperature. Curves are cubic-spline smoothed with df = 5 on the top row and df = 10 on the bottom row.
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pone.0153343.g012: Thermodynamic parameters trends.Trends in the mean thermodynamic parameters (, ΔCP and n) for strains above (solid lines) and below (dashed lines) quantile curves versus temperature. Curves are cubic-spline smoothed with df = 5 on the top row and df = 10 on the bottom row.

Mentions: The quantile curves were calculated from the complete data set while the individual growth curves were calculated for strains with at least 5 data points and which had distinct peaks. It was clear that the fitted curves for some strains exceeded some quantile curves while others did not. In order to simplify the results below we define two terms. We refer to strains that exceed the quantile curves as ‘exceedance strains’ and the others as ‘non-exceedance strains’. The exceedance strains could be thought as exhibiting relatively faster growth compared to non-exceedance strains. We calculated the mean thermodynamic parameters of the exceedance and non-exceedance strains for each quantile for a series of narrow temperature bins. We show the posterior means of , ΔCP and n for exceedance and non-exceedance strains in Fig 12. We omit the C parameter in the figure since it is simply a scaling parameter. We do not consider those parameters to be independent, either in a biological or a statistical sense. Since there were only a few growth curves that exceeded the upper quantiles we smoothed the trends to highlight the posterior trends with temperature. The plots show the mean trends and not their variabilities, which, in any case, are considerable, as is visually evident from the sensitivity of the curves to smoothing.


The Biokinetic Spectrum for Temperature.

Corkrey R, McMeekin TA, Bowman JP, Ratkowsky DA, Olley J, Ross T - PLoS ONE (2016)

Thermodynamic parameters trends.Trends in the mean thermodynamic parameters (, ΔCP and n) for strains above (solid lines) and below (dashed lines) quantile curves versus temperature. Curves are cubic-spline smoothed with df = 5 on the top row and df = 10 on the bottom row.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835062&req=5

pone.0153343.g012: Thermodynamic parameters trends.Trends in the mean thermodynamic parameters (, ΔCP and n) for strains above (solid lines) and below (dashed lines) quantile curves versus temperature. Curves are cubic-spline smoothed with df = 5 on the top row and df = 10 on the bottom row.
Mentions: The quantile curves were calculated from the complete data set while the individual growth curves were calculated for strains with at least 5 data points and which had distinct peaks. It was clear that the fitted curves for some strains exceeded some quantile curves while others did not. In order to simplify the results below we define two terms. We refer to strains that exceed the quantile curves as ‘exceedance strains’ and the others as ‘non-exceedance strains’. The exceedance strains could be thought as exhibiting relatively faster growth compared to non-exceedance strains. We calculated the mean thermodynamic parameters of the exceedance and non-exceedance strains for each quantile for a series of narrow temperature bins. We show the posterior means of , ΔCP and n for exceedance and non-exceedance strains in Fig 12. We omit the C parameter in the figure since it is simply a scaling parameter. We do not consider those parameters to be independent, either in a biological or a statistical sense. Since there were only a few growth curves that exceeded the upper quantiles we smoothed the trends to highlight the posterior trends with temperature. The plots show the mean trends and not their variabilities, which, in any case, are considerable, as is visually evident from the sensitivity of the curves to smoothing.

Bottom Line: We found another peak at 67°C and a steady decline in maximum rates thereafter.We used a thermodynamic model to recover the Δ-shape, suggesting that the growth rate limits arise from a trade-off between activity and stability of proteins.The spectrum provides underpinning principles that will find utility in models concerned with the thermal responses of biological processes.

View Article: PubMed Central - PubMed

Affiliation: Tasmanian Institute of Agriculture / School of Land and Food, University of Tasmania, Hobart, Tasmania, Australia.

ABSTRACT
We identify and describe the distribution of temperature-dependent specific growth rates for life on Earth, which we term the biokinetic spectrum for temperature. The spectrum has the potential to provide for more robust modeling in thermal ecology since any conclusions derived from it will be based on observed data rather than using theoretical assumptions. It may also provide constraints for systems biology model predictions and provide insights in physiology. The spectrum has a Δ-shape with a sharp peak at around 42°C. At higher temperatures up to 60°C there was a gap of attenuated growth rates. We found another peak at 67°C and a steady decline in maximum rates thereafter. By using Bayesian quantile regression to summarise and explore the data we were able to conclude that the gap represented an actual biological transition between mesophiles and thermophiles that we term the Mesophile-Thermophile Gap (MTG). We have not identified any organism that grows above the maximum rate of the spectrum. We used a thermodynamic model to recover the Δ-shape, suggesting that the growth rate limits arise from a trade-off between activity and stability of proteins. The spectrum provides underpinning principles that will find utility in models concerned with the thermal responses of biological processes.

No MeSH data available.


Related in: MedlinePlus