A Fermentor System for Regulating Oxygen at Low Concentrations in Cultures of
            <i>Saccharomyces cerevisiae</i>

Burke, Patricia V.; Kwast, Kurt E.; Everts, Frank; Poyton, Robert O.

doi:10.1128/aem.64.3.1040-1044.1998

Cited by 19 publications

(7 citation statements)

References 17 publications

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“…The S. cerevisiae strain JM43 ( MATα leu2-3,112 his4-580 trp1-289 ura3-52 [ρ +] )[ 50 ] was used. Liquid pre-cultures were grown in a semi-synthetic galactose medium containing Tween 80, ergosterol, and silicon antifoam (SSG-TEA) [ 51 ] with shaking (300 rpm) for 3 – 4 days prior to inoculating a NewBrunswick BioFlo III fermentor (3.5 l working volume) [ 52 ]. Batch fermentor cultures were inoculated with a volume of pre-culture to allow for at least six generations of aerobic growth before reaching a cell density of ≈ 1 Klett unit.…”

Section: Methodsmentioning

confidence: 99%

Comparison of the transcriptomic "stress response" evoked by antimycin A and oxygen deprivation in saccharomyces cerevisiae

et al. 2008

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BackgroundAcute changes in environmental parameters (e.g., O2, pH, UV, osmolarity, nutrients, etc.) evoke a common transcriptomic response in yeast referred to as the "environmental stress response" (ESR) or "common environmental response" (CER). Why such a diverse array of insults should elicit a common transcriptional response remains enigmatic. Previous functional analyses of the networks involved have found that, in addition to up-regulating those for mitigating the specific stressor, the majority appear to be involved in balancing energetic supply and demand and modulating progression through the cell cycle. Here we compared functional and regulatory aspects of the stress responses elicited by the acute inhibition of respiration with antimycin A and oxygen deprivation under catabolite non-repressed (galactose) conditions.ResultsGene network analyses of the transcriptomic responses revealed both treatments result in the transient (10 – 60 min) down-regulation of MBF- and SBF-regulated networks involved in the G1/S transition of the cell cycle as well as Fhl1 and PAC/RRPE-associated networks involved in energetically costly programs of ribosomal biogenesis and protein synthesis. Simultaneously, Msn2/4 networks involved in hexose import/dissimilation, reserve energy regulation, and autophagy were transiently up-regulated. Interestingly, when cells were treated with antimycin A well before experiencing anaerobiosis these networks subsequently failed to respond to oxygen deprivation. These results suggest the transient stress response is elicited by the acute inhibition of respiration and, we postulate, changes in cellular energetics and/or the instantaneous growth rate, not oxygen deprivation per se. After a considerable delay (≥ 1 generation) under anoxia, predictable changes in heme-regulated gene networks (e.g., Hap1, Hap2/3/4/5, Mot3, Rox1 and Upc2) were observed both in the presence and absence of antimycin A.ConclusionThis study not only differentiates between the gene networks that respond to respiratory inhibition and those that respond to oxygen deprivation but suggests the function of the ESR or CER is to balance energetic supply/demand and coordinate growth with the cell cycle, whether in response to perturbations that disrupt catabolic pathways or those that require rapidly up-regulating energetically costly programs for combating specific stressors.

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Section: Methodsmentioning

confidence: 99%

Comparison of the transcriptomic "stress response" evoked by antimycin A and oxygen deprivation in saccharomyces cerevisiae

et al. 2008

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“…The three PLS models developed in the current study indicated that the H/D of the bioreactor and PID control of dissolved oxygen concentration had a significant impact on the production of biomass, cyt b5, and respective production yield. In fermenters, regulation of dissolved oxygen concentration may be fine-tuned by a PID algorithm, especially when oxygen supply is controlled by stirring speed [ 53 , 54 ]. Adjustment of the three parameters may improve the regulation for low oxygen concentrations [ 52 ].…”

Section: Discussionmentioning

confidence: 99%

Optimization of Multiparameters for Increased Yields of Cytochrome B5 in Bioreactors

Pereira

Carvalho

2021

Molecules

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The production of recombinant proteins is gaining increasing importance as the market requests high quality proteins for several applications. However, several process parameters affect both the growth of cells and product yields. This study uses high throughput systems and statistical methods to assess the influence of fermentation conditions in lab-scale bioreactors. Using this methodology, it was possible to find the best conditions to produce cytochrome b5 with recombinant cells of Escherichia coli. Using partial least squares, the height-to-diameter ratio of the bioreactor, aeration rate, and PID controller parameters were found to contribute significantly to the final biomass and cytochrome concentrations. Hence, we could use this information to fine-tune the process parameters, which increased cytochrome production and yield several-fold. Using aeration of 1 vvm, a bioreactor with a height-to-ratio of 2.4 and tuned PID parameters, a production of 72.72 mg/L of cytochrome b5 in the culture media, and a maximum of product to biomass yield of 24.97 mg/g could be achieved.

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“…7B , cells were grown in YEP media supplemented with 2% dextrose or 4% galactose. In the case of the nitrogen shift experiments, assays were performed using cells grown in 600 ml of semisynthetic medium (SSD) containing per liter, 3 g of yeast extract, 10 g of dextrose, 0.8 g of NH 4 SO 4 , 1 g of KH 2 PO 4 , 0.5 g of NaCl, 0.5 g of CaCl 2 •2H 2 O, 0.3 g of MgSO 4 , 1.1 μg of FeCl 3 •6H 2 O, supplemented with amino acids, adenine and uracil at 40 μg/ml, 0.1% (V/V) Tween 80, 20 μg/ml of ergosterol and 350 ppm of antifoam B emulsion (Sigma-Aldrich, St. Louis, MO) [ 63 ] using Multifors (Infors Canada, Anjou, QC, Canada) bioreactors. Cells were grown to 0.3 OD 600 in air-supplemented media than the gas supply was shifted to nitrogen.…”

Section: Methodsmentioning

confidence: 99%

Transcriptome Wide Annotation of Eukaryotic RNase III Reactivity and Degradation Signals

et al. 2015

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Detection and validation of the RNA degradation signals controlling transcriptome stability are essential steps for understanding how cells regulate gene expression. Here we present complete genomic and biochemical annotations of the signals required for RNA degradation by the dsRNA specific ribonuclease III (Rnt1p) and examine its impact on transcriptome expression. Rnt1p cleavage signals are randomly distributed in the yeast genome, and encompass a wide variety of sequences, indicating that transcriptome stability is not determined by the recurrence of a fixed cleavage motif. Instead, RNA reactivity is defined by the sequence and structural context in which the cleavage sites are located. Reactive signals are often associated with transiently expressed genes, and their impact on RNA expression is linked to growth conditions. Together, the data suggest that Rnt1p reactivity is triggered by malleable RNA degradation signals that permit dynamic response to changes in growth conditions.

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A Fermentor System for Regulating Oxygen at Low Concentrations in Cultures of Saccharomyces cerevisiae

Cited by 19 publications

References 17 publications

Comparison of the transcriptomic "stress response" evoked by antimycin A and oxygen deprivation in saccharomyces cerevisiae

Comparison of the transcriptomic "stress response" evoked by antimycin A and oxygen deprivation in saccharomyces cerevisiae

Optimization of Multiparameters for Increased Yields of Cytochrome B5 in Bioreactors

Transcriptome Wide Annotation of Eukaryotic RNase III Reactivity and Degradation Signals

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