scholarly journals Subunit interaction of vacuolar H+-pyrophosphatase as determined by high hydrostatic pressure

1998 ◽  
Vol 331 (2) ◽  
pp. 395-402 ◽  
Author(s):  
Su J. YANG ◽  
Shu J. KO ◽  
Yuan R. TSAI ◽  
Shih S. JIANG ◽  
Soong Y. KUO ◽  
...  
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Spectroscopic Techniques ◽  
Dependent Manner ◽  
Pressure Treatment ◽  
Concentration Dependent Manner ◽  
Subunit Dissociation ◽  
Km Value ◽  
And Function

Vacuolar H+-pyrophosphatase (H+-PPase) from etiolated hypocotyls of mung bean (Vigna radiata L.) is a homodimer with a molecular mass of 145 kDa. The vacuolar H+-PPase was subjected to high hydrostatic pressure to investigate its structure and function. The inhibition of H+-PPase activity by high hydrostatic pressure has a pressure-, time- and protein-concentration-dependent manner. The Vmax value of vacuolar H+-PPase was dramatically decreased by pressurization from 293.9 to 70.2 µmol of PPi (pyrophosphate) consumed/h per mg of protein, while the Km value decreased from 0.35 to 0.08 mM, implying that the pressure treatment increased the affinity of PPi to vacuolar H+-PPase but decreased its hydrolysis. The physiological substrate and its analogues enhance high pressure inhibition of vacuolar H+-PPase. The HPLC profile reveals high pressure treatment of H+-PPase provokes the subunit dissociation from an active into inactive form. High hydrostatic pressure also induces the conformational change of vacuolar H+-PPase as determined by spectroscopic techniques. Our results indicate the importance of protein–protein interaction for this novel proton-translocating enzyme. Working models are proposed to interpret the pressure inactivation of vacuolar H+-PPase. We also suggest that association of identical subunits of vacuolar H+-PPase is not random but proceeds in a specific manner.

scholarly journals Effect of ultra-high hydrostatic pressure on the survival of Chromohalobacter beijerinckii

2016 ◽  
Vol 72 (6) ◽  
pp. 364-368
Author(s):  
Janina Pęconek ◽  
Monika Fonberg-Broczek ◽  
Jacek Szczawiński ◽  
Dorota Sawilska-Rautenstrauch
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Nutrient Broth ◽  
Aerobic Bacteria ◽  
Pressure Treatment ◽  
Average Sensitivity ◽  
High Pressure Treatment ◽  
Smoked Salmon ◽  
D Values

The aim of the study was to determine the effect of ultra-high hydrostatic pressure on the survival of Chromohalobacter beijerinckii in samples of nutrient broth containing a 6% addition of NaCl and in samples of cold-smoked salmon. Both types of samples were exposed to ultra-high hydrostatic pressure of 300 and 400 MPa for 0, 5, 10 and 15 min. The number of Chromohalobacter beijerinckii was determined in all control samples and samples subjected to high pressure. The total number of aerobic bacteria was additionally determined in the samples of cold-smoked salmon intentionally inoculated with Chromohalobacter beijerinckii. It was found that Chromohalobacter beijerinckii showed a clearly greater sensitivity to high hydrostatic pressure in the nutrient broth (D-values: 300 MPa - 3.72 min; 400 MPa - 1.90 min) than it did in the samples of cold-smoked salmon (D-values: 300 MPa - 5.83 min; 400 MPa - 3.08 min). The results concerning the total number of aerobic bacteria show that Chromohalobacter beijerinckii is more susceptible to high pressure than the accompanying microflora present in cold-smoked salmon. High pressure treatment at 400 MPa applied for 15 min caused a destruction of Chromohalobacter beijerinckii cells that was clearly visible under a scanning electron microscope. Chromohalobacter beijerinckii belongs to bacteria that have average sensitivity to high hydrostatic pressure.

scholarly journals Pressure-Induced Differential Regulation of the Two Tryptophan Permeases Tat1 and Tat2 by Ubiquitin Ligase Rsp5 and Its Binding Proteins, Bul1 and Bul2

2003 ◽  
Vol 23 (21) ◽  
pp. 7566-7584 ◽  
Author(s):  
Fumiyoshi Abe ◽  
Hidetoshi Iida
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Lipid Rafts ◽  
Ubiquitin Ligase ◽  
High Hydrostatic Pressure ◽  
State Level ◽  
Limiting Factor ◽  
Dependent Manner ◽  
Double Mutation ◽  
Tryptophan Uptake

ABSTRACT Tryptophan uptake appears to be the Achilles' heel in yeast physiology, since under a variety of seemingly diverse toxic conditions, it becomes the limiting factor for cell growth. When growing cells of Saccharomyces cerevisiae are subjected to high hydrostatic pressure, tryptophan uptake is down-regulated, leading to cell cycle arrest in the G1 phase. Here we present evidence that the two tryptophan permeases Tat1 and Tat2 are differentially regulated by Rsp5 ubiquitin ligase in response to high hydrostatic pressure. Analysis of high-pressure growth mutants revealed that the HPG1 gene was allelic to RSP5. The HPG1 mutation or the bul1Δ bul2Δ double mutation caused a marked increase in the steady-state level of Tat2 but not of Tat1, although both permeases were degraded at high pressure in an Rsp5-dependent manner. There were marked differences in subcellular localization. Tat1 localized predominantly in the plasma membrane, whereas Tat2 was abundant in the internal membranes. Moreover, Tat1 was associated with lipid rafts, whereas Tat2 localized in bulk lipids. Surprisingly, Tat2 became associated with lipid rafts upon the occurrence of a ubiquitination defect. These results suggest that ubiquitination is an important determinant of the localization and regulation of these tryptophan permeases. Determination of the activation volume (ΔV ≠) for Tat1- and Tat2-mediated tryptophan uptake (89.3 and 50.8 ml/mol, respectively) revealed that both permeases are highly sensitive to membrane perturbation and that Tat1 rather than Tat2 is likely to undergo a dramatic conformational change during tryptophan import. We suggest that hydrostatic pressure is a unique tool for elucidating the dynamics of integral membrane protein functions as well as for probing lipid microenvironments where they localize.

scholarly journals Inactivation of Escherichia coli andListeria innocua in Milk by Combined Treatment with High Hydrostatic Pressure and the Lactoperoxidase System

2000 ◽  
Vol 66 (10) ◽  
pp. 4173-4179 ◽  
Author(s):  
Cristina García-Graells ◽  
Caroline Valckx ◽  
Chris W. Michiels
Keyword(s):  
Escherichia Coli ◽  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Combined Treatment ◽  
Food Preservation ◽  
Pressure Treatment ◽  
E Coli ◽  
Preservation Method ◽  
Lactoperoxidase System

ABSTRACT We have studied inactivation of four strains each ofEscherichia coli and Listeria innocua in milk by the combined use of high hydrostatic pressure and the lactoperoxidase-thiocyanate-hydrogen peroxide system as a potential mild food preservation method. The lactoperoxidase system alone exerted a bacteriostatic effect on both species for at least 24 h at room temperature, but none of the strains was inactivated. Upon high-pressure treatment in the presence of the lactoperoxidase system, different results were obtained for E. coli and L. innocua. For none of the E. coli strains did the lactoperoxidase system increase the inactivation compared to a treatment with high pressure alone. However, a strong synergistic interaction of both treatments was observed for L. innocua. Inactivation exceeding 7 decades was achieved for all strains with a mild treatment (400 MPa, 15 min, 20°C), which in the absence of the lactoperoxidase system caused only 2 to 5 decades of inactivation depending on the strain. Milk as a substrate was found to have a considerable effect protecting E. coli and L. innocua against pressure inactivation and reducing the effectiveness of the lactoperoxidase system under pressure on L. innocua. Time course experiments showed that L. innocua counts continued to decrease in the first hours after pressure treatment in the presence of the lactoperoxidase system.E. coli counts remained constant for at least 24 h, except after treatment at the highest pressure level (600 MPa, 15 min, 20°C), in which case, in the presence of the lactoperoxidase system, a transient decrease was observed, indicating sublethal injury rather than true inactivation.

Effects of high hydrostatic pressure on Campylobacter jejuni in poultry meat

2015 ◽  
Vol 18 (2) ◽  
pp. 261-266 ◽  
Author(s):  
A. Jackowska-Tracz ◽  
M. Tracz
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Campylobacter Jejuni ◽  
High Hydrostatic Pressure ◽  
High Pressure Processing ◽  
Poultry Meat ◽  
Chicken Breast ◽  
Regression Equations ◽  
Dependent Manner ◽  
Piston Cylinder

Abstract Campylobacter jejuni inactivation by high pressure processing (HPP) in poultry meat (chicken breast) was investigated. The pressure was created by high hydrostatic pressure piston-cylinder food processor. Contaminated with C. jejuni (108 CFU g−1) samples of ground poultry meat were hermetically sealed in a polyamide-polyethylene bags and exposed to HPP for 9 different combinations of pressure (200 MPa, 300 MPa and 400 MPa) and time (5 min, 10 min and 15 min). Quantitative bacteriological analysis was carried out in order to determine the number of surviving C. jejuni cells. The obtained results showed that C. jejuni is relatively sensitive to high pressure treatment as compared to other food-borne pathogens. The loss of C. jejuni viability increased in a dose- and time-dependent manner. On the basis of the results, D-values were calculated. For reduction C. jejuni in poultry meat by 6 log units (6D-values), considered as sufficient for consumer protection, the application of 300 MPa for 8.73 min, or 400 MPa for 4.37 min is needed. The linear regression equations, which has been calculated on the basis of this study, allows to determine the degree of C. jejuni reduction in poultry meat for any selected duration of pressurization in a given pressure range.

Predictive Model for Inactivation of Campylobacter spp. by Heat and High Hydrostatic Pressure

2007 ◽  
Vol 70 (9) ◽  
pp. 2023-2029 ◽  
Author(s):  
SEHAM LORI ◽  
ROMAN BUCKOW ◽  
DIETRICH KNORR ◽  
VOLKER HEINZ ◽  
ANSELM LEHMACHER
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Poultry Meat ◽  
Inactivation Kinetics ◽  
Order Kinetic ◽  
Pressure Treatment ◽  
Short Term ◽  
Short Term Treatment ◽  
High Pressure Treatment

Campylobacter represents one of the leading causes of foodborne enteritis. Poultry and its products frequently transmit the pathogen. The objective of the present study was to model predictively the short-term inactivation of Campylobacter in a ready-to-eat poultry product to develop an economic high-pressure treatment. We inactivated baroresistant strains of Campylobacter jejuni and Campylobacter coli, grown to stationary phase on nutrient agar and inoculated in poultry meat slurry, by heat and high hydrostatic pressure. Incubation at ambient pressure at 70°C for 1 min and at 450 MPa at 15°C for 30 s inactivated more than 6 log CFU of this foodborne pathogen per ml of poultry meat slurry. Thermal and pressure inactivation kinetics of C. coli and C. jejuni in poultry meat slurry were accurately described by a first-order kinetic model. A mathematical model was developed from 10 to 65°C and from ambient to 500 MPa that predicts the reduction in numbers of Campylobacter in response to the combination of temperature, pressure, and treatment time. We suggest the high-pressure treatment of foods to avoid health risks caused by Campylobacter. The nonthermal short-term treatment of the examined food model system represents a successful step to an economic high-pressure procedure.

scholarly journals Inactivation of Geobacillus stearothermophilus Spores by High-Pressure Carbon Dioxide Treatment

2003 ◽  
Vol 69 (12) ◽  
pp. 7124-7129 ◽  
Author(s):  
Taisuke Watanabe ◽  
Soichi Furukawa ◽  
Junichi Hirata ◽  
Tetsuya Koyama ◽  
Hirokazu Ogihara ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Activation Energy ◽  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Bacillus Coagulans ◽  
Bacterial Spores ◽  
Pressure Treatment ◽  
Geobacillus Stearothermophilus ◽  
High Hydrostatic Pressure Treatment

ABSTRACT High-pressure CO2 treatment has been studied as a promising method for inactivating bacterial spores. In the present study, we compared this method with other sterilization techniques, including heat and pressure treatment. Spores of Bacillus coagulans, Bacillus subtilis, Bacillus cereus, Bacillus licheniformis, and Geobacillus stearothermophilus were subjected to CO2 treatment at 30 MPa and 35°C, to high-hydrostatic-pressure treatment at 200 MPa and 65°C, or to heat treatment at 0.1 MPa and 85°C. All of the bacterial spores except the G. stearothermophilus spores were easily inactivated by the heat treatment. The highly heat- and pressure-resistant spores of G. stearothermophilus were not the most resistant to CO2 treatment. We also investigated the influence of temperature on CO2 inactivation of G. stearothermophilus. Treatment with CO2 and 30 MPa of pressure at 95°C for 120 min resulted in 5-log-order spore inactivation, whereas heat treatment at 95°C for 120 min and high-hydrostatic-pressure treatment at 30 MPa and 95°C for 120 min had little effect. The activation energy required for CO2 treatment of G. stearothermophilus spores was lower than the activation energy for heat or pressure treatment. Although heat was not necessary for inactivationby CO2 treatment of G. stearothermophilus spores, CO2 treatment at 95°C was more effective than treatment at 95°C alone.

scholarly journals Evaluation of Structural Changes Induced by High Hydrostatic Pressure in Leuconostoc mesenteroides

2004 ◽  
Vol 70 (2) ◽  
pp. 1116-1122 ◽  
Author(s):  
Gönül Kaletunç ◽  
Jaesung Lee ◽  
Hami Alpas ◽  
Faruk Bozoglu
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Structural Changes ◽  
Leuconostoc Mesenteroides ◽  
Pressure Treatment ◽  
Scanning Calorimetry ◽  
Whole Cells ◽  
Dsc Studies ◽  
Dsc Thermograms

ABSTRACT Scanning electron microcopy (SEM), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC) were used to evaluate structural changes in Leuconostoc mesenteroides cells as a function of high-hydrostatic-pressure treatment. This bacterium usually grows in chains of cells, which were increasingly dechained at elevated pressures. High-pressure treatments at 250 and 500 MPa also caused changes in the external surface and internal structure of cells. Dechaining and blister formation on the surface of cells increased with pressure, as observed in SEM micrographs. TEM studies showed that cytoplasmic components of the cells were affected by high-pressure treatment. DSC studies of whole cells showed increasing denaturation of ribosomes with pressure, in keeping with dense compacted regions in the cytoplasm of pressure-treated cells observed in TEM micrographs. Apparent reduction of intact ribosomes observed in DSC thermograms was related to the reduction in number of viable cells. The results indicate that inactivation of L. mesenteroides cells is mainly due to ribosomal denaturation observed as a reduction of the corresponding peak in DSC thermograms and condensed interior regions of cytoplasm in TEM micrographs.

Biomechanical and immunohistochemical properties of meniscal cartilage after high hydrostatic pressure treatment

2008 ◽  
Vol 87B (1) ◽  
pp. 19-25 ◽  
Author(s):  
Florian D. Naal ◽  
Johannes Schauwecker ◽  
Erwin Steinhauser ◽  
Stefan Milz ◽  
Fabian von Knoch ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Pressure Treatment ◽  
High Hydrostatic Pressure Treatment
Sign in / Sign up

Export Citation Format

Share Document