Heat Shock Induces Barotolerance in Listeria monocytogenes

2008 ◽  
Vol 71 (2) ◽  
pp. 426-430 ◽  
Author(s):  
MELINDA M. HAYMAN ◽  
RAMASWAMY C. ANANTHESWARAN ◽  
STEPHEN J. KNABEL
Keyword(s):  
High Pressure ◽  
Protein Synthesis ◽  
Listeria Monocytogenes ◽  
Heat Shock ◽  
Protective Effect ◽  
De Novo ◽  
High Pressure Processing ◽  
Milk Samples ◽  
Ultrahigh Temperature ◽  
De Novo Protein Synthesis

The aim of this study was to investigate the effect of heat shock on the resistance of Listeria monocytogenes to high pressure processing (HPP). L. monocytogenes ATCC 19115 was grown to stationary phase at 15°C and inoculated into whole ultrahigh-temperature milk at ~107 CFU/ml. Milk samples (5 ml) were placed into plastic transfer pipettes, which were heat sealed and then heated in a water bath at 48°C for 10 min. Immediately after heat shock, the milk was cooled in water (20°C) for 25 min and then placed on ice. The samples were high pressure processed at ambient temperature (~23°C) at 400 MPa for various times up to 150 s. Following HPP, the samples were spread plated on tryptic soy agar supplemented with yeast extract. Heat shock significantly increased the D400 MPa-value of L. monocytogenes from 35 s in non–heat-shocked cells to 127 s in heat-shocked cells (P < 0.05). Addition of chloramphenicol before heat shock eliminated the protective effect of heat shock (P < 0.05). Heat shock for 5, 10, 15, or 30 min at 48°C resulted in maximal barotolerance (P < 0.05); increasing the time to 60 min significantly decreased survival compared with that at 5, 10, 15, or 30 min (P < 0.05). These results indicate that prior heat shock significantly increases the barotolerance of L. monocytogenes and that de novo protein synthesis during heat shock is required for this enhanced barotolerance.

Cytoplasmic and secreted Saccharomyces cerevisiae invertase mRNAs encoded by one gene can be differentially or coordinately regulated

1984 ◽  
Vol 4 (9) ◽  
pp. 1682-1688
Author(s):  
D Perlman ◽  
P Raney ◽  
H O Halvorson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Synthesis ◽  
Heat Shock ◽  
De Novo ◽  
Signal Sequence ◽  
Hormone Treatment ◽  
Mrna Levels ◽  
Secretion Signal ◽  
Cycle Arrest ◽  
De Novo Protein Synthesis

A single structural gene, SUC2, encodes both secreted and cytoplasmic invertase in Saccharomyces cerevisiae. It is known that the unprocessed polypeptides which differ by a secretion signal sequence are encoded by separate mRNAs. This unusual transcriptional organization raises the question as to the degree to which the transcripts can be independently regulated. To define a system for studying this problem, we examined invertase transcription after various physiological perturbations of cells: rapid catabolite derepression, heat shock, and cell cycle arrest. With each treatment, fluctuations in mRNA levels for both cytoplasmic and secreted invertase were observed. We concluded that (i) catabolite-derepressed synthesis of the mRNAs occurs rapidly after a drop in glucose, is a sustained response, and does not require de novo protein synthesis; (ii) heat shock transcription of both invertase mRNAs is, in contrast, a brief and transient response requiring de novo protein synthesis; and (iii) alpha-mating hormone treatment (G1 phase arrest and release) results in regular and coordinated synthesis of both mRNAs midway between rounds of histone mRNA synthesis. We propose that invertase mRNA regulation involves constitutively synthesized transcriptional factors (observed during catabolite derepression) and transient factors (observed during heat shock and possibly during synchronous growth). Moreover, the mRNA levels for secreted and cytoplasmic invertase can be independently regulated.

scholarly journals Cytoplasmic and secreted Saccharomyces cerevisiae invertase mRNAs encoded by one gene can be differentially or coordinately regulated.

1984 ◽  
Vol 4 (9) ◽  
pp. 1682-1688 ◽  
Author(s):  
D Perlman ◽  
P Raney ◽  
H O Halvorson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Synthesis ◽  
Heat Shock ◽  
De Novo ◽  
Signal Sequence ◽  
Hormone Treatment ◽  
Mrna Levels ◽  
Secretion Signal ◽  
Cycle Arrest ◽  
De Novo Protein Synthesis

A single structural gene, SUC2, encodes both secreted and cytoplasmic invertase in Saccharomyces cerevisiae. It is known that the unprocessed polypeptides which differ by a secretion signal sequence are encoded by separate mRNAs. This unusual transcriptional organization raises the question as to the degree to which the transcripts can be independently regulated. To define a system for studying this problem, we examined invertase transcription after various physiological perturbations of cells: rapid catabolite derepression, heat shock, and cell cycle arrest. With each treatment, fluctuations in mRNA levels for both cytoplasmic and secreted invertase were observed. We concluded that (i) catabolite-derepressed synthesis of the mRNAs occurs rapidly after a drop in glucose, is a sustained response, and does not require de novo protein synthesis; (ii) heat shock transcription of both invertase mRNAs is, in contrast, a brief and transient response requiring de novo protein synthesis; and (iii) alpha-mating hormone treatment (G1 phase arrest and release) results in regular and coordinated synthesis of both mRNAs midway between rounds of histone mRNA synthesis. We propose that invertase mRNA regulation involves constitutively synthesized transcriptional factors (observed during catabolite derepression) and transient factors (observed during heat shock and possibly during synchronous growth). Moreover, the mRNA levels for secreted and cytoplasmic invertase can be independently regulated.

scholarly journals Unravelling the Molecular Mechanisms Underlying the Protective Effect of Lactate on the High-Pressure Resistance of Listeria monocytogenes

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 677
Author(s):  
Cristina Serra-Castelló ◽  
Ilario Ferrocino ◽  
Anna Jofré ◽  
Luca Cocolin ◽  
Sara Bover-Cid ◽  
...  
Keyword(s):  
High Pressure ◽  
Protective Effect ◽  
Molecular Mechanisms ◽  
Rna Extraction ◽  
Meat Products ◽  
High Pressure Processing ◽  
Membrane Properties ◽  
Short Exposure ◽  
Cooked Ham ◽  
Pressure Resistance

Formulations with lactate as an antimicrobial and high-pressure processing (HPP) as a lethal treatment are combined strategies used to control L. monocytogenes in cooked meat products. Previous studies have shown that when HPP is applied in products with lactate, the inactivation of L. monocytogenes is lower than that without lactate. The purpose of the present work was to identify the molecular mechanisms underlying the piezo-protection effect of lactate. Two L. monocytogenes strains (CTC1034 and EGDe) were independently inoculated in a cooked ham model medium without and with 2.8% potassium lactate. Samples were pressurized at 400 MPa for 10 min at 10 °C. Samples were subjected to RNA extraction, and a shotgun transcriptome sequencing was performed. The short exposure of L. monocytogenes cells to lactate through its inoculation in a cooked ham model with lactate 1h before HPP promoted a shift in the pathogen’s central metabolism, favoring the metabolism of propanediol and ethanolamine together with the synthesis of the B12 cofactor. Moreover, the results suggest an activated methyl cycle that would promote modifications in membrane properties resulting in an enhanced resistance of the pathogen to HPP. This study provides insights on the mechanisms developed by L. monocytogenes in response to lactate and/or HPP and sheds light on the understanding of the piezo-protective effect of lactate.

scholarly journals Viral Gene Expression Patterns in Human Herpesvirus 6B-Infected T Cells

2002 ◽  
Vol 76 (15) ◽  
pp. 7578-7586 ◽  
Author(s):  
Bodil Øster ◽  
Per Höllsberg
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Protein Synthesis ◽  
De Novo ◽  
Expression Patterns ◽  
Human Herpesvirus ◽  
Viral Gene Expression ◽  
Polymerase Activity ◽  
Viral Gene ◽  
De Novo Protein Synthesis

ABSTRACT Herpesvirus gene expression is divided into immediate-early (IE) or α genes, early (E) or β genes, and late (L) or γ genes on the basis of temporal expression and dependency on other gene products. By using real-time PCR, we have investigated the expression of 35 human herpesvirus 6B (HHV-6B) genes in T cells infected by strain PL-1. Kinetic analysis and dependency on de novo protein synthesis and viral DNA polymerase activity suggest that the HHV-6B genes segregate into six separate kinetic groups. The genes expressed early (groups I and II) and late (groups V and VI) corresponded well with IE and L genes, whereas the intermediate groups III and IV contained E and L genes. Although HHV-6B has characteristics similar to those of other roseoloviruses in its overall gene regulation, we detected three B-variant-specific IE genes. Moreover, genes that were independent of de novo protein synthesis clustered in an area of the viral genome that has the lowest identity to the HHV-6A variant. The organization of IE genes in an area of the genome that differs from that of HHV-6A underscores the distinct differences between HHV-6B and HHV-6A and may provide a basis for further molecular and immunological analyses to elucidate their different biological behaviors.

De novo protein synthesis in relation to ammonia and proline accumulation in water stressed white clover

2004 ◽  
Vol 31 (8) ◽  
pp. 847 ◽  
Author(s):  
Tae-Hwan Kim ◽  
Bok-Rye Lee ◽  
Woo-Jin Jung ◽  
Kil-Yong Kim ◽  
Jean-Christophe Avice ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Water Deficit ◽  
White Clover ◽  
De Novo ◽  
Proline Accumulation ◽  
Leaf Water ◽  
Total N ◽  
Water Parameters ◽  
Leaves And Roots ◽  
De Novo Protein Synthesis

The kinetics of protein incorporation from newly-absorbed nitrogen (N, de novo protein synthesis) was estimated by 15N tracing in 18-week-old white clover plants (Trifolium repens L. cv. Regal) during 7 d of water-deficit treatment. The physiological relationship between kinetics and accumulation of proline and ammonia in response to the change in leaf-water parameters was also assessed. All leaf-water parameters measured decreased gradually under water deficit. Leaf and root dry mass was not significantly affected during the first 3 d when decreases in leaf-water parameters were substantial. However, metabolic parameters such as total N, proline and ammonia were significantly affected within 1 d of commencement of water-deficit treatment. Water-deficit treatment significantly increased the proline and NH3–NH4+ concentrations in both leaves and roots. There was a marked reduction in the amount of N incorporated into the protein fraction from the newly absorbed N (NANP) in water-deficit stressed plants, particularly in leaf tissue. This reduction in NANP was strongly associated with an increased concentration of NH3–NH4+ in roots (P≤0.05) and proline (P≤0.01) in leaves and roots. These results suggest that proline accumulation may be a sensitive biochemical indicator of plant water status and of the dynamics of de novo protein synthesis in response to stress severity.

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