scholarly journals Amino acid homeostatic control by TORC1 in Saccharomyces cerevisiae under high hydrostatic pressure

2020 ◽  
Vol 133 (17) ◽  
pp. jcs245555
Author(s):  
Satoshi Uemura ◽  
Takahiro Mochizuki ◽  
Kengo Amemiya ◽  
Goyu Kurosaka ◽  
Miho Yazawa ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
High Pressure ◽  
Amino Acid ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Intracellular Accumulation ◽  
Intracellular Amino Acid ◽  
Regulatory Circuit ◽  
Nutrient Signaling ◽  
Glutamine Synthesis

ABSTRACTMechanical stresses, including high hydrostatic pressure, elicit diverse physiological effects on organisms. Gtr1, Gtr2, Ego1 (also known as Meh1) and Ego3 (also known as Slm4), central regulators of the TOR complex 1 (TORC1) nutrient signaling pathway, are required for the growth of Saccharomyces cerevisiae cells under high pressure. Here, we showed that a pressure of 25 MPa (∼250 kg/cm2) stimulates TORC1 to promote phosphorylation of Sch9, which depends on the EGO complex (EGOC) and Pib2. Incubation of cells at this pressure aberrantly increased glutamine and alanine levels in the ego1Δ, gtr1Δ, tor1Δ and pib2Δ mutants, whereas the polysome profiles were unaffected. Moreover, we found that glutamine levels were reduced by combined deletions of EGO1, GTR1, TOR1 and PIB2 with GLN3. These results suggest that high pressure leads to the intracellular accumulation of amino acids. Subsequently, Pib2 loaded with glutamine stimulates the EGOC–TORC1 complex to inactivate Gln3, downregulating glutamine synthesis. Our findings illustrate the regulatory circuit that maintains intracellular amino acid homeostasis and suggest critical roles for the EGOC–TORC1 and Pib2–TORC1 complexes in the growth of yeast under high hydrostatic pressure.

scholarly journals Molecular Responses to High Hydrostatic Pressure in Eukaryotes: Genetic Insights from Studies on Saccharomyces cerevisiae

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1305
Author(s):  
Fumiyoshi Abe
Keyword(s):  
Saccharomyces Cerevisiae ◽  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
High Pressures ◽  
Strong Association ◽  
Pressure Effects ◽  
Basic Knowledge ◽  
Challenger Deep ◽  
Human Joints

High hydrostatic pressure is common mechanical stress in nature and is also experienced by the human body. Organisms in the Challenger Deep of the Mariana Trench are habitually exposed to pressures up to 110 MPa. Human joints are intermittently exposed to hydrostatic pressures of 3–10 MPa. Pressures less than 50 MPa do not deform or kill the cells. However, high pressure can have various effects on the cell’s biological processes. Although Saccharomyces cerevisiae is not a deep-sea piezophile, it can be used to elucidate the molecular mechanism underlying the cell’s responses to high pressures by applying basic knowledge of the effects of pressure on industrial processes involving microorganisms. We have explored the genes associated with the growth of S. cerevisiae under high pressure by employing functional genomic strategies and transcriptomics analysis and indicated a strong association between high-pressure signaling and the cell’s response to nutrient availability. This review summarizes the occurrence and significance of high-pressure effects on complex metabolic and genetic networks in eukaryotic cells and how the cell responds to increasing pressure by particularly focusing on the physiology of S. cerevisiae at the molecular level. Mechanosensation in humans has also been discussed.

scholarly journals Pressure-Induced Endocytic Degradation of the Saccharomyces cerevisiae Low-Affinity Tryptophan Permease Tat1 Is Mediated by Rsp5 Ubiquitin Ligase and Functionally Redundant PPxY Motif Proteins

2013 ◽  
Vol 12 (7) ◽  
pp. 990-997 ◽  
Author(s):  
Asaha Suzuki ◽  
Takahiro Mochizuki ◽  
Satoshi Uemura ◽  
Toshiki Hiraki ◽  
Fumiyoshi Abe
Keyword(s):  
Saccharomyces Cerevisiae ◽  
High Pressure ◽  
Hydrostatic Pressure ◽  
Ubiquitin Ligase ◽  
High Hydrostatic Pressure ◽  
Intracellular Localization ◽  
Normal Growth ◽  
Growth Conditions ◽  
Content Type ◽  
Genes Encoding

ABSTRACT Cells of Saccharomyces cerevisiae express two tryptophan permeases, Tat1 and Tat2, which have different characteristics in terms of their affinity for tryptophan and intracellular localization. Although the high-affinity permease Tat2 has been well documented in terms of its ubiquitin-dependent degradation, the low-affinity permease Tat1 has not yet been characterized fully. Here we show that a high hydrostatic pressure of 25 MPa triggers a degradation of Tat1 which depends on Rsp5 ubiquitin ligase and the EH domain-containing protein End3. Tat1 was resistant to a 3-h cycloheximide treatment, suggesting that it is highly stable under normal growth conditions. The ubiquitination of Tat1 most likely occurs at N-terminal lysines 29 and 31. Simultaneous substitution of arginine for the two lysines prevented Tat1 degradation, but substitution of either of them alone did not, indicating that the roles of lysines 29 and 31 are redundant. When cells were exposed to high pressure, Tat1-GFP was completely lost from the plasma membrane, while substantial amounts of Tat1 K29R-K31R -GFP remained. The HPG1-1 (Rsp5 P514T ) and rsp5-ww3 mutations stabilized Tat1 under high pressure, but any one of the rsp5-ww1 , rsp5-ww2 , and bul1 Δ bul2 Δ mutations or single deletions of genes encoding arrestin-related trafficking adaptors did not. However, simultaneous loss of 9-arrestins and Bul1/Bul2 prevented Tat1 degradation at 25 MPa. The results suggest that multiple PPxY motif proteins share some essential roles in regulating Tat1 ubiquitination in response to high hydrostatic pressure.

Effect of High Hydrostatic Pressure on Salmonella Inoculated into Creamy Peanut Butter with Modified Composition

2014 ◽  
Vol 77 (10) ◽  
pp. 1664-1668 ◽  
Author(s):  
TANYA D'SOUZA ◽  
MUKUND KARWE ◽  
DONALD W. SCHAFFNER
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Water Activity ◽  
High Hydrostatic Pressure ◽  
Peanut Butter ◽  
High Pressure Processing ◽  
Peanut Oil ◽  
Peanut Flour ◽  
Log Reduction ◽  
High Hydrostatic Pressure Processing

Peanut butter has been associated with several large foodborne salmonellosis outbreaks. This research investigates the potential of high hydrostatic pressure processing (HPP) for inactivation of Salmonella in peanut butter of modified composition, both by modifying its water activity as well by the addition of various amounts of nisin. A cocktail of six Salmonella strains associated with peanut butter and nut-related outbreaks was used for all experiments. Different volumes of sterile distilled water were added to peanut butter to increase water activity, and different volumes of peanut oil were added to decrease water activity. Inactivation in 12% fat, light roast, partially defatted peanut flour, and peanut oil was also quantified. Nisaplin was incorporated into peanut butter at four concentrations corresponding to 2.5, 5.0, 12.5, and 25.0 ppm of pure nisin. All samples were subjected to 600 MPa for 18 min. A steady and statistically significant increase in log reduction was seen as added moisture was increased from 50 to 90%. The color of all peanut butter samples containing added moisture contents darkened after high pressure processing. The addition of peanut oil to further lower the water activity of peanut butter further reduced the effectiveness of HPP. Just over a 1-log reduction was obtained in peanut flour, while inactivation to below detection limits (2 log CFU/g) was observed in peanut oil. Nisin alone without HPP had no effect. Recovery of Salmonella after a combined nisin and HPP treatment did show increased log reduction with longer storage times. The maximum log reduction of Salmonella achieved was 1.7 log CFU/g, which was comparable to that achieved by noncycling pressure treatment alone. High pressure processing alone or with other formulation modification, including added nisin, is not a suitable technology to manage the microbiological safety of Salmonella-contaminated peanut butter.

scholarly journals High-Pressure Inactivation of Hepatitis A Virus within Oysters

2005 ◽  
Vol 71 (1) ◽  
pp. 339-343 ◽  
Author(s):  
Kevin R. Calci ◽  
Gloria K. Meade ◽  
Robert C. Tezloff ◽  
David H. Kingsley
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Natural Conditions ◽  
Direct Evaluation ◽  
Temperature Range

ABSTRACT Previous results demonstrated that hepatitis A virus (HAV) could be inactivated by high hydrostatic pressure (HHP) (D. H. Kingsley, D. Hoover, E. Papafragkou, and G. P. Richards, J. Food Prot. 65:1605-1609, 2002); however, direct evaluation of HAV inactivation within contaminated oysters was not performed. In this study, we report confirmation that HAV within contaminated shellfish is inactivated by HHP. Shellfish were initially contaminated with HAV by using a flowthrough system. PFU reductions of >1, >2, and >3 log10 were observed for 1-min treatments at 350, 375, and 400 megapascals, respectively, within a temperature range of 8.7 to 10.3�C. Bioconcentration of nearly 6 log10 PFU of HAV per oyster was achieved under simulated natural conditions. These results suggest that HHP treatment of raw shellfish will be a viable strategy for the reduction of infectious HAV.

Effect of high pressure on various diffusion mechanisms in oxygen-deficient ReBa2Cu3O7−x (Re = Y, Ho) single crystals

2019 ◽  
Vol 33 (04) ◽  
pp. 1950039
Author(s):  
G. Ya. Khadzhai ◽  
N. R. Vovk ◽  
R. V. Vovk ◽  
I. L. Goulatis ◽  
O. V. Dobrovolskiy
Keyword(s):  
High Pressure ◽  
Electrical Resistivity ◽  
Hydrostatic Pressure ◽  
Single Crystals ◽  
High Hydrostatic Pressure ◽  
Room Temperature ◽  
Diffusion Mechanisms ◽  
Diffusion Coalescence

The effect of high hydrostatic pressure on the relaxation of the electrical resistivity at room temperature of oxygen-nonstoichiometric [Formula: see text] (Re = Y, Ho) single crystals is investigated. The application of hydrostatic pressure has been revealed to significantly intensify the process of diffusion coalescence in the oxygen subsystem. At the same time, the intensity of the redistribution of labile oxygen is significantly changed when yttrium is replaced by holmium.

scholarly journals The multifaceted effects of DMSO and high hydrostatic pressure on the kinetic constants of hydrolysis reactions catalyzed by α-chymotrypsin

2020 ◽  
Vol 22 (28) ◽  
pp. 16325-16333
Author(s):  
Lena Ostermeier ◽  
Rosario Oliva ◽  
Roland Winter
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Kinetic Constants ◽  
Antagonistic Effects ◽  
Hydrolysis Reactions

The cosolvent DMSO and high pressure have antagonistic effects on the kinetic constants of α-chymotrypsin-catalyzed hydrolysis reactions.

scholarly journals Alicyclobacillus acidoterrestris Strain Variability in the Inactivation Kinetics of Spores in Orange Juice by Temperature-Assisted High Hydrostatic Pressure

2020 ◽  
Vol 10 (21) ◽  
pp. 7542
Author(s):  
Patra Sourri ◽  
Anthoula A. Argyri ◽  
Efstathios Z. Panagou ◽  
George-John E. Nychas ◽  
Chrysoula C. Tassou
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Orange Juice ◽  
High Hydrostatic Pressure ◽  
Reference Strain ◽  
Wild Type Strain ◽  
Weibull Model ◽  
Inactivation Kinetics ◽  
High Pressure Level ◽  
Kinetics Of

In this work, the inactivation kinetics of Alicyclobacillus acidoterrestris spores by temperature-assisted high hydrostatic pressure was assessed by means of the Weibull model. Spores from two A. acidoterrestris strains (a wild-type strain and a reference strain) were inoculated in commercial orange juice and subjected to high pressure levels (500 and 600 MPa) combined with four temperature regimes (25, 45, 60 and 70 °C) for time up to 30 min. Results showed that for a given high-pressure level spore inactivation was higher as temperature progressively increased. Furthermore, the Weibull model consistently produced satisfactory fit to the inactivation data based on the values of the root mean squared error (RMSE < 0.54 log colony-forming units (CFU)/mL) and the coefficient of determination (R2 > 0.90 in most cases). The shape of inactivation curves was concave upward (p < 1) for all temperature/high pressure levels tested, indicating rapid inactivation of the sensitive cells of the bacterium whereas the remaining ones adapted to high hydrostatic pressure (HHP) treatment. The values of the shape (p) and scale (δ) parameters of the Weibull model were dependent on the applied temperature for a given high pressure level and they were further described in a secondary model using first-order fitting curves to provide predictions of the surviving spore population at 55 and 65 °C. Results revealed a systematic over-prediction for the wild-type strain regardless of temperature and high pressure applied, whereas for the reference strain under-prediction was evident after 3 log-cycles reduction of the surviving bacteria spores. Overall, the results obtained indicate that the effectiveness of high hydrostatic pressure against A. acidoterrestris spores is strain-dependent and also underline the need for temperature-assisted HPP for effective spore inactivation during orange juice processing.

Concurrent Effects of High Hydrostatic Pressure, Acidity and Heat on the Destruction and Injury of Yeasts

1995 ◽  
Vol 58 (3) ◽  
pp. 301-304 ◽  
Author(s):  
YOGA PANDYA ◽  
FRED F. JEWETT ◽  
DALLAS G. HOOVER
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Potato Dextrose Agar ◽  
Plate Count ◽  
Citrate Buffer ◽  
Zygosaccharomyces Bailii ◽  
Mild Heat ◽  
Yeast Cultures ◽  
Colony Forming Units

Saccharomyces cerevisiae ATCC 2373 and Zygosaccharomyces bailii ATCC 36947 were exposed to hydrostatic pressures ranging from 1,500 to 3,000 atmospheres for 10, 20 and 30 min in 0.1 M citrate buffer at pH 3.0, 4.0 and 5.0 at 25 and 45°C. Inactivation of inoculated yeast cultures was achieved in spaghetti sauce with meat at 25°C with 3,000 atmospheres for 10 min and also at 45°C and 2,500 atmospheres for 10 min. Viable counts were determined on potato dextrose agar (PDA) incubated at 30°C for 48 h. Pressure-induced injury was demonstrated by plate count differential between PDA and PDA supplemented with glucose (PDAG). A reduction of 7-log10 cycles colony forming units (CFU)/ml was seen for both strains at 3,000 atmospheres for 10 min at 25°C at all pH levels and at 2,250 atmospheres, pH 5.0 for 20 min at 45°C. At 2,000 atmospheres, pH 3.0 for 30 min, the increase in temperature from 25 to 45°C increased the inactivation of yeast by 6-log10 cycles. Lowering the pH from 5.0 to 3.0 enhanced lethality up to 2-log10 cycles at 2,250 atmospheres, 25°C for 30 min. Injury was most apparent at exposure parameters that produced 3- to 5-log10 cycle reductions on PDA. This was achieved (99% injury) at 2,250 atmospheres, 25°C for 30 min. These data indicate that mild heat and acidity contribute to the effectiveness of the inactivation and injury of yeast by high hydrostatic pressure (HHP).

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