Effect of sucrose and sodium chloride on the survival and metabolic activity of Lactococcus lactis under high-pressure conditions

Molina-Gutierrez, Adriana; Rademacher, B.; Gänzle, Michael G.; Vogel, Rudi F.

doi:10.1016/s0921-0423(02)80115-0

Cited by 16 publications

(15 citation statements)

References 18 publications

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“…The survival of vegetative cells is strongly dependent on the food matrix (4,(6)(7)(8)(9). Sublethally injured cells may loose their resistance to adverse environmental conditions, e.g., low pH or the presence of osmolites (6,7,(10)(11)(12).…”

Section: Introductionmentioning

confidence: 99%

High pressure-sensitive gene expression in Lactobacillus sanfranciscensis

Vogel

Pavlovic

Hörmann

et al. 2005

Braz J Med Biol Res

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Lactobacillus sanfranciscensis is a Gram-positive lactic acid bacterium used in food biotechnology. It is necessary to investigate many aspects of a model organism to elucidate mechanisms of stress response, to facilitate preparation, application and performance in food fermentation, to understand mechanisms of inactivation, and to identify novel tools for high pressure biotechnology. To investigate the mechanisms of the complex bacterial response to high pressure we have analyzed changes in the proteome and transcriptome by 2-D electrophoresis, and by microarrays and real time PCR, respectively. More than 16 proteins were found to be differentially expressed upon high pressure stress and were compared to those sensitive to other stresses. Except for one apparently high pressure-specific stress protein, no pressure-specific stress proteins were found, and the proteome response to pressure was found to differ from that induced by other stresses. Selected pressure-sensitive proteins were partially sequenced and their genes were identified by reverse genetics. In a transcriptome analysis of a redundancy cleared shot gun library, about 7% of the genes investigated were found to be affected. Most of them appeared to be up-regulated 2-to 4-fold and these results were confirmed by real time PCR. Gene induction was shown for some genes up-regulated at the proteome level (clpL/groEL/rbsK), while the response of others to high hydrostatic pressure at the transcriptome level seemed to differ from that observed at the proteome level. The up-regulation of selected genes supports the view that the cell tries to compensate for pressure-induced impairment of translation and membrane transport.

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Section: Introductionmentioning

confidence: 99%

High pressure-sensitive gene expression in Lactobacillus sanfranciscensis

Vogel

Pavlovic

Hörmann

et al. 2005

Braz J Med Biol Res

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“…The influence of salts or sugars on the water activity (a w ) of foods or suspension media does not explain the marked baroprotective effects of these solutes (21,29), and it has been suggested that specific interactions between sugars and biological macromolecules contribute to their baroprotective effects (11). A comparable protective effect against pressure inactivation of Lactococcus lactis was achieved by addition of 3 M NaCl or 0.5 M sucrose, which resulted in a w values of 0.917 and 0.985, respectively (21). Furthermore, ionic and nonionic solutes had different effects on physiological properties of pressure-treated cells.…”

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confidence: 97%

“…Baroprotective effects of sodium chloride or sugars have been observed in studies with Escherichia coli, Saccharomyces cerevisiae, Zygosaccharomyces spp., and Rhodoturula rubra (14,17,24,25,36). The influence of salts or sugars on the water activity (a w ) of foods or suspension media does not explain the marked baroprotective effects of these solutes (21,29), and it has been suggested that specific interactions between sugars and biological macromolecules contribute to their baroprotective effects (11). A comparable protective effect against pressure inactivation of Lactococcus lactis was achieved by addition of 3 M NaCl or 0.5 M sucrose, which resulted in a w values of 0.917 and 0.985, respectively (21).…”

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confidence: 99%

“…Sucrose preserved the metabolic activity and membrane integrity of the cells during the high-pressure treatment, whereas salt preserved the membrane integrity but not the metabolic activity. L. lactis confronted with a decreased a w accumulates different compatible solutes depending on whether the reduction in the a w is achieved with an ionic solute or a nonionic solute (20), and preliminary evidence has suggested that the accumulation of compatible solutes is involved in the baroprotective effect of NaCl (21).…”

mentioning

confidence: 99%

“…Therefore, we determined the effects of sucrose and NaCl on the intracellular pH and membrane protein LmrP of L. lactis cells during and after high-pressure treatment. Based on previous investigations on the baroprotective effects of NaCl and sucrose (21), in this study the NaCl and sucrose levels were chosen to examine comparable baroprotective effects on cell counts and sublethal injury of L. lactis. Furthermore, the effects of solutes at the level of the membrane phase transition under normal and high-pressure conditions were studied.…”

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confidence: 99%

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Protective Effect of Sucrose and Sodium Chloride for Lactococcus lactis during Sublethal and Lethal High-Pressure Treatments

Molina-Höppner

Doster

Vogel

et al. 2004

Appl Environ Microbiol

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172

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The bactericidal effect of hydrostatic pressure is reduced when bacteria are suspended in media with high osmolarity. To elucidate mechanisms responsible for the baroprotective effect of ionic and nonionic solutes, Lactococcus lactis was treated with pressures ranging from 200 to 600 MPa in a low-osmolarity buffer or with buffer containing 0.5 M sucrose or 4 M NaCl. Pressure-treated cells were characterized in order to determine viability, the transmembrane difference in pH (⌬pH), and multiple-drug-resistance (MDR) transport activity. Furthermore, pressure effects on the intracellular pH and the fluidity of the membrane were determined during pressure treatment. In the presence of external sucrose and NaCl, high intracellular levels of sucrose and lactose, respectively, were accumulated by L. lactis; 4 M NaCl and, to a lesser extent, 0.5 M sucrose provided protection against pressure-induced cell death. The transmembrane ⌬pH was reversibly dissipated during pressure treatment in any buffer system. Sucrose but not NaCl prevented the irreversible inactivation of enzymes involved in pH homeostasis and MDR transport activity. In the presence 0.5 M sucrose or 4 M NaCl, the fluidity of the cytoplasmic membrane was maintained even at low temperatures and high pressure. These results indicate that disaccharides protect microorganisms against pressure-induced inactivation of vital cellular components. The protective effect of ionic solutes relies on the intracellular accumulation of compatible solutes as a response to the osmotic stress. Thus, ionic solutes provide only asymmetric protection, and baroprotection with ionic solutes requires higher concentrations of the osmolytes than of disaccharides.The accumulation of compatible solutes, such as betaines, proline, and sugars, is a widespread response of microorganisms to elevated environmental osmotic pressures (41). According to a recent definition, a compatible solute is a "cytoplasmic cosolvent (solute) whose levels can be modulated over a broad range without disrupting cellular function" (24, 43). Compatible solutes contribute to the osmotic balance with the extracellular environment, enhance the stability of enzymes, and preserve the integrity of biological membranes (41). The composition of the osmolytes that are accumulated depends on the type of osmotic shock (i.e., ionic stress versus nonionic stress) and the presence of specific compatible solutes in the medium. In addition to their role as osmotic balancers, compatible solutes provide protection against high temperature, freeze-thaw treatment, and drying (41, 43).When the osmotic pressure of the medium is increased, the tolerance of microorganisms to high hydrostatic pressure is enhanced. Baroprotective effects of sodium chloride or sugars have been observed in studies with Escherichia coli, Saccharomyces cerevisiae, Zygosaccharomyces spp., and Rhodoturula rubra (14,17,24,25,36). The influence of salts or sugars on the water activity (a w ) of foods or suspension media does not explain the marked baroprotectiv...

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Effect of high‐pressure processing on the microbial load and functionality of sugar‐cookie dough

et al. 2020

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Background and objectives Refrigerated dough products have the potential to be a safety hazard to consumers because they could be consumed raw or undercooked. The objectives of this study were designed to evaluate the microbial and functionality changes in high pressured sugar‐cookie dough as a function of aw (0.80–0.87), pressure level (100–600 MPa), and holding time (1–6 min). Findings Endogenous microbial populations were marginally reduced (0.2–0.5 log CFU/g) by pressure treatments. However, treating the dough at 600 MPa for 6 min significantly reduced counts of inoculated Escherichia coli by as much as 2.0 log CFU/g. Increasing the aw of cookie dough from 0.80 to 0.87 did not play a significant role in the reduction of microbial counts; however, it yielded a softer and thicker cookie when baked. Dough and cookie physical characteristics did not differ significantly among HPP‐treated and control doughs within the same aw level. Conclusions The results of this study suggest that pressure treatment has the potential to improve the microbiological quality of wheat‐based cookie doughs. However, variations in food matrix composition must be considered because some food constituents, such as sugar and fat, may protect microorganisms against pressure‐induced inactivation. Significance and novelty The results reported here have practical implications for the food industry and contributes to understand the effects of high‐pressure processing on wheat‐based cookie doughs and their microbial loads.

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Effect of sucrose and sodium chloride on the survival and metabolic activity of Lactococcus lactis under high-pressure conditions

Cited by 16 publications

References 18 publications

High pressure-sensitive gene expression in Lactobacillus sanfranciscensis

High pressure-sensitive gene expression in Lactobacillus sanfranciscensis

Protective Effect of Sucrose and Sodium Chloride for Lactococcus lactis during Sublethal and Lethal High-Pressure Treatments

Effect of high‐pressure processing on the microbial load and functionality of sugar‐cookie dough

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