High Hydrostatic Pressure Come-Up Time and Yeast Viability

1998 ◽  
Vol 61 (12) ◽  
pp. 1657-1660 ◽  
Author(s):  
E. PALOU ◽  
A. LÓPEZ-MALO ◽  
G. V. BARBOSA-CÁNOVAS ◽  
J. WELTI-CHANES ◽  
P. M. DAVIDSON ◽  
...  
Keyword(s):  
Growth Phase ◽  
Growth Cycle ◽  
Stationary Growth Phase ◽  
Yeast Cells ◽  
Exponential Growth Phase ◽  
Stationary Growth ◽  
Survival Fraction ◽  
Zygosaccharomyces Bailii ◽  
Yeast Viability ◽  
Increased Sensitivity

The effects of the come-up time at selected pressures (50 to 689 MPa) on Saccharomyces cerevisiae and Zygosaccharomyces bailii viability were evaluated at 21°C. For Z. bailii the effects of the water activity (aw) of the suspension media and the stage of the growth cycle were also investigated. Pressure come-up times exerted an important effect on the yeast survival fraction, decreasing counts as pressure increased. An increased sensitivity to pressure treatments was observed with yeast cells from the exponential growth phase. Lethality increased as aw of the suspension media increased. For an aw of 0.98 and cells from the stationary growth phase, pressure treatments at less than 200 MPa had no effect on Z. bailii viability; however, no survivors (<10 CFU/ml) were observed in treatments applied only for the time needed to reach pressures greater than 517 MPa. Yeast survivor curves showed an excellent fit (r > 0.996) when described by a phenomenological model based on the Fermi equation, S(P) = 1/|1 + exp[(P − Pc)/k]|, where S(P) is the survival fraction, P is the pressure, Pc is a critical pressure corresponding to 50% survival, and k is a constant representing the steepness of the curve.

Occurrence of “Stress"-Proteins in Yeast after Heat-Shock, Acrylonitrile Treatment and during the Stationary Growth Phase

1985 ◽  
Vol 40 (1-2) ◽  
pp. 26-28 ◽  
Author(s):  
Ulrich Pfeffer ◽  
Bernd Schulz-Harder
Keyword(s):  
Heat Shock ◽  
Growth Phase ◽  
Exponential Growth ◽  
Stress Proteins ◽  
Stationary Growth Phase ◽  
Yeast Cells ◽  
Exponential Growth Phase ◽  
Stationary Growth ◽  
Molecular Weights

The response of yeast cells to different kinds of “stress” is not identical. Cells of the stationary growth phase synthesize three new proteins of molecular weights 68, 27 and 24 kD, compared with cells of the exponential growth phase, while heat-shocked cells exhibit new proteins of 100, 90. 84, 70 and 24 kD. After treatment with acrylonitrile two new proteins with molecular weights of 70 and 46 kD appear. However, all three kinds of “stress” lead to the induction of a ribonuclease.

scholarly journals THE FATE OF MITOCHONDRIA DURING AGING IN TETRAHYMENA PYRIFORMIS

1964 ◽  
Vol 20 (1) ◽  
pp. 113-129 ◽  
Author(s):  
Alfred M. Elliott ◽  
Il Jin Bak
Keyword(s):  
Growth Phase ◽  
Tetrahymena Pyriformis ◽  
Growth Cycle ◽  
Stationary Growth Phase ◽  
Stationary Growth ◽  
Logarithmic Growth Phase ◽  
Cytoplasmic Structures ◽  
Hydrolysis Of ◽  
Logarithmic Growth ◽  
Single Mitochondrion

During the growth cycle of Tetrahymena pyriformis the mitochondria undergo changes in position, number, and structure. Ciliates in the logarithmic growth phase possess elongated mitochondria which are aligned along the plasma membrane and are closely associated with the kinetosomes and kinetodesmata. Mitochondria appear to divide across the long axis at this time, resulting in two or more products. Throughout this phase of growth mitochondrial divisions keep pace with cytokinesis so that the population of mitochondria remains at essentially the minimal level. As the ciliates enter the stationary growth phase the mitochondria increase in number, become oval to spherical in shape, and some migrate into the cytoplasm. Intramitochondrial masses of various configurations appear at this time. Some of the mitochondria lying in the cytoplasm become incorporated into vacuoles. Within these vacuoles either a single mitochondrion appears or several mitochondria may be seen along with other cytoplasmic structures. Later in the stationary growth phase the contained mitochondria are dense and the tubules are more compact than normal. Various stages in disorganization of the mitochondria are observed in a single large vacuole. Cytochemical tests reveal the presence of acid phosphatase, suggesting that hydrolysis of the vacuolar contents occurs. Lipid droplets increase in number during the middle and late stationary phase of growth. These events are interpreted as being associated with the normal process of aging in T. pyriformis.

The Impact of Antibacterial Peptides on Bacterial Lipid Membranes Depends on Stage of Growth

2020 ◽  
Author(s):  
Tzong-Hsien Lee ◽  
Vinzenz Hofferek ◽  
Marc-antoine Sani ◽  
Frances Separovic ◽  
Gavin Reid ◽  
...  
Keyword(s):  
Growth Phase ◽  
Lipid Membranes ◽  
Stationary Growth Phase ◽  
Exponential Growth Phase ◽  
Antibacterial Peptides ◽  
Stationary Growth ◽  
E Coli ◽  
Bacterial Lipid ◽  
Supported Lipid Membranes ◽  
The Impact

The impact of maculatin 1.1 (Mac1) on the mechanical properties of supported lipid membranes derived from exponential growth phase (EGP) and stationary growth phase (SGP) E. coli lipid extracts was...

scholarly journals Analysis of cell-growth-phase-related variations in hyaluronate synthase activity of isolated plasma-membrane fractions of cultured human skin fibroblasts

1986 ◽  
Vol 237 (2) ◽  
pp. 333-342 ◽  
Author(s):  
N Mian
Keyword(s):  
Plasma Membrane ◽  
Growth Phase ◽  
Plasma Membranes ◽  
Glucuronic Acid ◽  
Stationary Growth Phase ◽  
Binding Activity ◽  
Exponential Growth Phase ◽  
Human Skin Fibroblasts ◽  
Stationary Growth ◽  
Hyaluronate Synthase

Hyaluronate synthase activity is localized exclusively in plasma-membrane fractions of cultured human skin fibroblasts. The enzyme activity of plasma membranes prepared from exponential-growth-phase cells was about 6.5 times that of stationary-growth-phase cells. Hyaluronate synthase from exponential-growth-phase cells exhibited lower Km and higher Vmax. values for both UDP-N-acetylglucosamine and UDP-glucuronic acid and higher rate of elongation of hyaluronate chains compared with the enzyme from stationary-growth-phase cells. Hyaluronate synthase exhibited an extremely short half-life, 2.2 h and 3.8 h respectively when cells were treated with cycloheximide and actinomycin D. The cell-growth-phase-dependent variations in hyaluronate synthase activity appear to be due to its high turnover rate as well as due to some post-translational modification of the enzyme protein as cells progress from early exponential to stationary growth phase. The isolated plasma membranes contained a protein (Mr approx. 450,000) that was selectively autophosphorylated from [gamma-32P]ATP in vitro in the presence of hyaluronate precursors in the reaction mixture and that also exhibited some hyaluronate-synthesis-related properties. The 32P-labelled protein isolated from plasma membranes of exponentially growing cells expressed an efficient UDP-[14C]glucuronic acid- and UDP-N-acetyl[3H]glucosamine-binding activity and was able to synthesize oligosaccharides (Mr 5000) of [14C]glucuronic acid and N-acetyl[3H]glucosamine residues. The corresponding protein of stationary-growth-phase cells, which expressed much higher nucleotide-sugar-precursor-binding activity, appeared to have lost its oligosaccharide-synthesizing activity.

Construction of a [NiFe]-hydrogenase deletion mutant of Desulfovibrio vulgaris Hildenborough

2005 ◽  
Vol 33 (1) ◽  
pp. 59-60 ◽  
Author(s):  
A. Goenka ◽  
J.K. Voordouw ◽  
W. Lubitz ◽  
W. Gärtner ◽  
G. Voordouw
Keyword(s):  
Growth Phase ◽  
Exponential Growth ◽  
Deletion Mutant ◽  
Stationary Growth Phase ◽  
Exponential Growth Phase ◽  
Desulfovibrio Vulgaris ◽  
Wild Type ◽  
Stationary Growth ◽  
Desulfovibrio Vulgaris Hildenborough ◽  
Mutant Cells

A mutant of Desulfovibrio vulgaris Hildenborough lacking a gene for [NiFe] hydrogenase was generated. Growth studies, performed for the mutant in comparison with the wild-type, showed no strong differences during the exponential growth phase. However, the mutant cells died more rapidly in the stationary growth phase.

scholarly journals Azithromycin Exhibits Bactericidal Effects on Pseudomonas aeruginosa through Interaction with the Outer Membrane

2005 ◽  
Vol 49 (4) ◽  
pp. 1377-1380 ◽  
Author(s):  
Yoshifumi Imamura ◽  
Yasuhito Higashiyama ◽  
Kazunori Tomono ◽  
Koichi Izumikawa ◽  
Katsunori Yanagihara ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Growth Phase ◽  
Exponential Growth ◽  
Divalent Cations ◽  
Stationary Growth Phase ◽  
Exponential Growth Phase ◽  
Stationary Growth ◽  
Outer Membranes ◽  
Bactericidal Effects

ABSTRACT The aim of the present study was to elucidate the effect of the macrolide antibiotic azithromycin on Pseudomonas aeruginosa. We studied the susceptibility to azithromycin in P. aeruginosa PAO1 using a killing assay. PAO1 cells at the exponential growth phase were resistant to azithromycin. In contrast, PAO1 cells at the stationary growth phase were sensitive to azithromycin. The divalent cations Mg2+ and Ca2+ inhibited this activity, suggesting that the action of azithromycin is mediated by interaction with the outer membranes of the cells, since the divalent cations exist between adjacent lipopolysaccharides (LPSs) and stabilize the outer membrane. The divalent cation chelator EDTA behaved in a manner resembling that of azithromycin; EDTA killed more PAO1 in the stationary growth phase than in the exponential growth phase. A 1-N-phenylnaphthylamine assay showed that azithromycin interacted with the outer membrane of P. aeruginosa PAO1 and increased its permeability while Mg2+ and Ca2+ antagonized this action. Our results indicate that azithromycin directly interacts with the outer membrane of P. aeruginosa PAO1 by displacement of divalent cations from their binding sites on LPS. This action explains, at least in part, the effectiveness of sub-MICs of macrolide antibiotics in pseudomonal chronic airway infection.

scholarly journals Role of the Stationary Growth Phase Sigma Factor RpoS of Burkholderia pseudomallei in Response to Physiological Stress Conditions

2003 ◽  
Vol 185 (23) ◽  
pp. 7008-7014 ◽  
Author(s):  
Benchamas Subsin ◽  
Mark S. Thomas ◽  
Gerd Katzenmeier ◽  
Jonathan G. Shaw ◽  
Sumalee Tungpradabkul ◽  
...  
Keyword(s):  
Growth Phase ◽  
Sigma Factor ◽  
Burkholderia Pseudomallei ◽  
Physiological Stress ◽  
Stationary Growth Phase ◽  
Null Mutant ◽  
Stationary Growth ◽  
Increased Sensitivity ◽  
And Oxidative Stress

ABSTRACT The Burkholderia pseudomallei rpoS gene was identified, and an rpoS null mutant was constructed. The mutant was shown to have an increased sensitivity to carbon starvation and oxidative stress. By using rpoS-lacZ fusions, transcription of rpoS was shown to be growth phase regulated, reaching a peak upon entry into stationary phase.

scholarly journals Surface of Lactic Acid Bacteria: Relationships between Chemical Composition and Physicochemical Properties

2000 ◽  
Vol 66 (6) ◽  
pp. 2548-2554 ◽  
Author(s):  
Christophe J. P. Boonaert ◽  
Paul G. Rouxhet
Keyword(s):  
Lactic Acid ◽  
Chemical Composition ◽  
Lactic Acid Bacteria ◽  
Physicochemical Properties ◽  
Growth Phase ◽  
Surface Composition ◽  
Stationary Growth Phase ◽  
Contact Angles ◽  
Exponential Growth Phase ◽  
Stationary Growth

ABSTRACT The surface chemical composition and physicochemical properties (hydrophobicity and zeta potential) of two lactic acid bacteria,Lactococcus lactis subsp. lactis bv. diacetilactis and Lactobacillus helveticus, have been investigated using cells harvested in exponential or stationary growth phase. The surface composition determined by X-ray photoelectron spectroscopy (XPS) was converted into a molecular composition in terms of proteins, polysaccharides, and hydrocarbonlike compounds. The concentration of the last was always below 15% (wt/wt), which is related to the hydrophilic character revealed by water contact angles of less than 30°. The surfaces of L. lactis cells had a polysaccharide concentration about twice that of proteins. The S-layer of L. helveticus was either interrupted or crossed by polysaccharide-rich compounds; the concentration of the latter was higher in the stationary growth phase than in the exponential growth phase. Further progress was made in the interpretation of XPS data in terms of chemical functions by showing that the oxygen component at 531.2 eV contains a contribution of phosphate in addition to the main contribution of the peptide link. The isoelectric points were around 2 and 3, and the electrophoretic mobilities above pH 5 (ionic strength, 1 mM) were about −3.0 × 10−8 and −0.6 × 10−8 m2 s−1 V−1 forL. lactis and L. helveticus, respectively. The electrokinetic properties of the latter reveal the influence of carboxyl groups, while the difference between the two strains is related to a difference between N/P surface concentration ratios, reflecting the relative exposure of proteins and phosphate groups at the surface.

scholarly journals Temporal Expression of the Bacillus subtilis secAGene, Encoding a Central Component of the Preprotein Translocase

1999 ◽  
Vol 181 (2) ◽  
pp. 493-500 ◽  
Author(s):  
Markus Herbort ◽  
Michael Klein ◽  
Erik H. Manting ◽  
Arnold J. M. Driessen ◽  
Roland Freudl
Keyword(s):  
Bacillus Subtilis ◽  
Growth Phase ◽  
Exponential Growth ◽  
De Novo ◽  
Stationary Growth Phase ◽  
Extracellular Proteins ◽  
Exponential Growth Phase ◽  
Central Component ◽  
Temporal Expression ◽  
Stationary Growth

ABSTRACT In Bacillus subtilis, the secretion of extracellular proteins strongly increases upon transition from exponential growth to the stationary growth phase. It is not known whether the amounts of some or all components of the protein translocation apparatus are concomitantly increased in relation to the increased export activity. In this study, we analyzed the transcriptional organization and temporal expression of the secA gene, encoding a central component of the B. subtilis preprotein translocase. We found that secA and the downstream gene (prfB) constitute an operon that is transcribed from a vegetative (ςA-dependent) promoter located upstream ofsecA. Furthermore, using different independent methods, we found that secA expression occurred mainly in the exponential growth phase, reaching a maximal value almost precisely at the transition from exponential growth to the stationary growth phase. Following to this maximum, the de novo transcription ofsecA sharply decreased to a low basal level. Since at the time of maximal secA transcription the secretion activity of B. subtilis strongly increases, our results clearly demonstrate that the expression of at least one of the central components of the B. subtilis protein export apparatus is adapted to the increased demand for protein secretion. Possible mechanistic consequences are discussed.

scholarly journals Model-based Characterization of the Parameters of Dissimilatory Sulfate Reduction Under the Effect of Different Initial Density of Desulfovibrio piger Vib-7 Bacterial Cells

2015 ◽  
Vol 9 (1) ◽  
pp. 55-69 ◽  
Author(s):  
Ivan Kushkevych ◽  
Marco Bolis ◽  
Milan Bartos
Keyword(s):  
Sulfate Reduction ◽  
Bacterial Growth ◽  
Growth Phase ◽  
Initial Density ◽  
Stationary Growth Phase ◽  
Exponential Growth Phase ◽  
Dissimilatory Sulfate Reduction ◽  
Bacterial Cells ◽  
Stationary Growth ◽  
Initial Concentration

The objective of this study was to design a model of dissimilatory sulfate reduction process using the Verhulst function, with a particular focus on the kinetics of bacterial growth, sulfate and lactate consumption, and accumulation of hydrogen sulfide and acetate. The effect of the initial density (0.12±0.011, 0.25±0.024, 0.5±0.048 and 1.0±0.096 mg cells/ml of medium) of the sulfate-reducing bacteriaDesulfovibrio pigerVib-7 on the growth and dissimilatory sulfate reduction was studied. The exponential growth phase of theD. pigerVib-7 was observed for 72 hours of cultivation at the (0.12 and 0.25 mg/ml) initial concentration of bacterial cells. Sulfate and lactate were consumed incompletely during this time. The increase in the initial concentration of cells to 0.5 and 1 mg/ml led to a shortening of the exponential bacterial growth phase and a shift to the stationary phase of the growth. In the case of 0.5 mg/ml seeding, the stationary growth phase was observed in the 36thhour of cultivation. The increase in the initial concentration of cells to 1 mg/ml led to the beginning of the stationary growth phase in 24th hours of cultivation. Under these conditions, sulfate and lactate were consumed completely in the 48th hour of cultivation. The kinetic analysis of the curves of bacterial growth and the process of dissimilatory sulfate reduction byD. pigerVib-7 was carried out.

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