Simple ingredients can approximate metabolic cycle without metals or enzymes

2020 ◽  
pp. 3-3
Author(s):  
Celia Henry Arnaud
Keyword(s):  
2014 ◽  
Author(s):  
Nikolai Slavov ◽  
David Botstein ◽  
Amy Caudy

Yeast cells grown in culture can spontaneously synchronize their respiration, metabolism, gene expression and cell division. Such metabolic oscillations in synchronized cultures reflect single-cell oscillations, but the relationship between the oscillations in single cells and synchronized cultures is poorly understood. To understand this relationship and the coordination between metabolism and cell division, we collected and analyzed DNA-content, gene-expression and physiological data, at hundreds of time-points, from cultures metabolically-synchronized at different growth rates, carbon sources and biomass densities. The data enabled us to extend and generalize our mechanistic model, based on ensemble average over phases (EAP), connecting the population-average gene-expression of asynchronous cultures to the gene-expression dynamics in the single-cells comprising the cultures. The extended model explains the carbon-source specific growth-rate responses of hundreds of genes. Our physiological data demonstrate that the frequency of metabolic cycling in synchronized cultures increases with the biomass density, suggesting that this cycling is an emergent behavior, resulting from the entraining of the single-cell metabolic cycle by a quorum-sensing mechanism, and thus underscoring the difference between metabolic cycling in single cells and in synchronized cultures. Measurements of constant levels of residual glucose across metabolically synchronized cultures indicate that storage carbohydrates are required to fuel not only the G1/S transition of the division cycle but also the metabolic cycle. Despite the large variation in profiled conditions and in the scale of their dynamics, most genes preserve invariant dynamics of coordination with each other and with the rate of oxygen consumption. Similarly, the G1/S transition always occurs at the beginning, middle or end of the high oxygen consumption phases, analogous to observations in human and drosophila cells. These results highlight evolutionary conserved coordination among metabolism, cell growth and division.


2019 ◽  
Vol 11 (21) ◽  
pp. 5918
Author(s):  
Gianoli ◽  
Bhatnagar

The impact of climate change dynamics has a multiplicative effect when the interlinkages between water and energy are considered. This also applies to climate change co-benefits that derive from adaptation and mitigation initiatives implemented at the urban level and that address the water-energy nexus. A better understanding of the water-energy nexus is a precondition for integrated resource planning that optimizes the use of scarce resources. Against this background, the paper assesses the potential impact of water-energy saving technologies (WEST) on the water-energy nexus of Cuenca, Ecuador, focusing on how vulnerability to climate change may affect the water metabolic cycle of the urban area. Water-energy saving technologies such as rainwater harvesting, solar water heaters, and micro water turbines, reduce water-related energy consumption and mitigate greenhouse gases emissions; thereby illustrating the potential to generate climate change mitigation and adaptation co-benefits. The paper relies on primary data collected through interviews and a survey as well as secondary data in order to assess the extent to which water-energy saving technologies influence the water-energy nexus in Cuenca’s urban water metabolic cycle. Within the context of climate change, the paper develops a business-as-usual scenario and assesses how this is modified by the implementation of water-energy saving technologies.


2016 ◽  
Vol 27 (1) ◽  
pp. 64-74 ◽  
Author(s):  
Anthony J. Burnetti ◽  
Mert Aydin ◽  
Nicolas E. Buchler

Cells have evolved oscillators with different frequencies to coordinate periodic processes. Here we studied the interaction of two oscillators, the cell division cycle (CDC) and the yeast metabolic cycle (YMC), in budding yeast. Previous work suggested that the CDC and YMC interact to separate high oxygen consumption (HOC) from DNA replication to prevent genetic damage. To test this hypothesis, we grew diverse strains in chemostat and measured DNA replication and oxygen consumption with high temporal resolution at different growth rates. Our data showed that HOC is not strictly separated from DNA replication; rather, cell cycle Start is coupled with the initiation of HOC and catabolism of storage carbohydrates. The logic of this YMC–CDC coupling may be to ensure that DNA replication and cell division occur only when sufficient cellular energy reserves have accumulated. Our results also uncovered a quantitative relationship between CDC period and YMC period across different strains. More generally, our approach shows how studies in genetically diverse strains efficiently identify robust phenotypes and steer the experimentalist away from strain-specific idiosyncrasies.


2015 ◽  
Vol 81 (18) ◽  
pp. 6484-6495 ◽  
Author(s):  
Archana Krishnamoorthy ◽  
J. Brian Robertson

ABSTRACTLuciferase is a useful, noninvasive reporter of gene regulation that can be continuously monitored over long periods of time; however, its use is problematic in fast-growing microbes like bacteria and yeast because rapidly changing cell numbers and metabolic states also influence bioluminescence, thereby confounding the reporter's signal. Here we show that these problems can be overcome in the budding yeastSaccharomyces cerevisiaeby simultaneously monitoring bioluminescence from two different colors of beetle luciferase, where one color (green) reports activity of a gene of interest, while a second color (red) is stably expressed and used to continuously normalize green bioluminescence for fluctuations in signal intensity that are unrelated to gene regulation. We use this dual-luciferase strategy in conjunction with a light-inducible promoter system to test whether different phases of yeast respiratory oscillations are more suitable for heterologous protein production than others. By using pulses of light to activate production of a green luciferase while normalizing signal variation to a red luciferase, we show that the early reductive phase of the yeast metabolic cycle produces more luciferase than other phases.


2011 ◽  
Vol 22 (12) ◽  
pp. 1997-2009 ◽  
Author(s):  
Nikolai Slavov ◽  
David Botstein

We studied the steady-state responses to changes in growth rate of yeast when ethanol is the sole source of carbon and energy. Analysis of these data, together with data from studies where glucose was the carbon source, allowed us to distinguish a “universal” growth rate response (GRR) common to all media studied from a GRR specific to the carbon source. Genes with positive universal GRR include ribosomal, translation, and mitochondrial genes, and those with negative GRR include autophagy, vacuolar, and stress response genes. The carbon source–specific GRR genes control mitochondrial function, peroxisomes, and synthesis of vitamins and cofactors, suggesting this response may reflect the intensity of oxidative metabolism. All genes with universal GRR, which comprise 25% of the genome, are expressed periodically in the yeast metabolic cycle (YMC). We propose that the universal GRR may be accounted for by changes in the relative durations of the YMC phases. This idea is supported by oxygen consumption data from metabolically synchronized cultures with doubling times ranging from 5 to 14 h. We found that the high oxygen consumption phase of the YMC can coincide exactly with the S phase of the cell division cycle, suggesting that oxidative metabolism and DNA replication are not incompatible.


1990 ◽  
Vol 46 (3) ◽  
pp. 367-379 ◽  
Author(s):  
Nicolas Kellershohn ◽  
Guillermo Mulliert ◽  
Jacques Ricard

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