Physiological response of Enterococcus faecalis JH2-2 to cold shock: growth at low temperatures and freezing/thawing challenge

Thammavongs, Bouachanh; Corroler, David; Panoff, Jean-Michel; Auffray, Yanick; Boutibonnes, P.

doi:10.1111/j.1472-765x.1996.tb01345.x

Cited by 74 publications

(28 citation statements)

References 31 publications

(23 reference statements)

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“…However, not all strains survived this process and viability rates as low as 0.1% have been reported (Abadias et al, 2001). The main reasons for bacteria viability loss during freeze-drying are ice crystal formation, membrane damage from high osmolarity due to high concentrations of internal solutes, macromolecule denaturation, and the removal of water, which affects the properties of many hydrophilic macromolecules in cells (Allison et al, 1999;Chitra et al, 2003;De Paz et al, 2002;Thammavongs et al, 1996). In the meantime, bacteria have developed adaptive strategies to face the challenges of changing environments and to survive under conditions of stress.…”

Section: Introductionmentioning

confidence: 99%

Effects of six substances on the growth and freeze-drying of Lactobacillus delbrueckii subsp. bulgaricus

Chen

Jie

Shi

et al. 2017

Acta Sci Pol Technol Aliment

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Background. The efficacy of Lactobacillus delbrueckii subsp. bulgaricus as starter cultures for the dairy industry depends largely on the number of viable and active cells. Freeze-drying is the most convenient and successful method to preserve the bacterial cells. However, not all strains survived during freeze-drying. Methods. The effects of six substances including NaCl, sorbitol, mannitol, mannose, sodium glutamate, betaine added to the MRS medium on the growth and freeze-drying survival rate and viable counts of Lb. delbrueckii subsp. bulgaricus were studied through a single-factor test and Plackett-Burman design. Subsequently, the optimum freeze-drying conditions of Lb. delbrueckii subsp. bulgaricus were determined. Results. Lb. delbrueckii subsp. bulgaricus survival rates were up to the maximum of 42.7%, 45.4%, 23.6%, while the concentrations of NaCl, sorbitol, sodium glutamate were 0.6%, 0.15%, 0.09%, respectively. In the optimum concentration, the viable counts in broth is 6.1, 6.9, 5.13 (×10 8 CFU/mL), respectively; the viable counts in freeze-drying power are 3.09, 5.2, 2.7 (×10 10 CFU/g), respectively. Conclusion. Three antifreeze factors including NaCl, sorbitol, sodium glutamate have a positive effect on the growth and freeze-drying of Lb. delbrueckii subsp. bulgaricus. The results are beneficial for developing Lb. delbrueckii subsp. bulgaricus.

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Section: Introductionmentioning

confidence: 99%

Effects of six substances on the growth and freeze-drying of Lactobacillus delbrueckii subsp. bulgaricus

Chen

Jie

Shi

et al. 2017

Acta Sci Pol Technol Aliment

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“…The point at which the slope changes is designated the critical temperature (T critical ). The existence of T critical has been reported for eurypsychrophiles, mesophiles, and thermophiles (5,6,9,12,13,15,22,35). The lack of T critical reports for stenopsychrophiles is probably because their growth rates have not been systematically examined at sufficiently low temperatures.…”

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confidence: 96%

Relationship of Critical Temperature to Macromolecular Synthesis and Growth Yield in Psychrobacter cryopegella

Bakermans

Nealson

2004

J Bacteriol

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Most microorganisms isolated from low-temperature environments (below 4°C) are eury-, not steno-, psychrophiles. While psychrophiles maximize or maintain growth yield at low temperatures to compensate for low growth rate, the mechanisms involved remain unknown, as does the strategy used by eurypsychrophiles to survive wide ranges of temperatures that include subzero temperatures. Our studies involve the eurypsychrophilic bacterium Psychrobacter cryopegella, which was isolated from a briny water lens within Siberian permafrost, where the temperature is ؊12°C. P. cryopegella is capable of reproducing from ؊10 to 28°C, with its maximum growth rate at 22°C. We examined the temperature dependence of growth rate, growth yield, and macromolecular (DNA, RNA, and protein) synthesis rates for P. cryopegella. Below 22°C, the growth of P. cryopegella was separated into two domains at the critical temperature (T critical ‫؍‬ 4°C). RNA, protein, and DNA synthesis rates decreased exponentially with decreasing temperatures. Only the temperature dependence of the DNA synthesis rate changed at T critical . When normalized to growth rate, RNA and protein synthesis reached a minimum at T critical , while DNA synthesis remained constant over the entire temperature range. Growth yield peaked at about T critical and declined rapidly as temperature decreased further. Similar to some stenopsychrophiles, P. cryopegella maximized growth yield at low temperatures and did so by streamlining growth processes at T critical . Identifying the specific processes which result in T critical will be vital to understanding both low-temperature growth and growth over a wide range of temperatures.Evolutionary adaptation to low-or high-temperature conditions often leads to the commitment to exist only in those conditions (28). However, eurythermal organisms tolerate and grow at a wide range of temperatures while stenothermal organisms are restricted to a narrow range (3). Hence, a eurypsychrophilic bacterium would be capable of growing over a wide range of low temperatures, from Ϫ10 to 0°C at the lower limit to 20 to 30°C at the upper limit. One such eurypsychrophilic bacterium is Psychrobacter cryopegella, isolated from a low-temperature (Ϫ12°C), saltwater lens in Siberian permafrost (4). This bacterium displays its maximum growth rate (i.e., has an optimal growth temperature [T opt ]) at 22°C yet is able to reproduce at temperatures as low as Ϫ10°C and as high as 30°C.Of major concern to organisms living over a wide range of temperatures is the fact that reaction rates decrease exponentially as temperature decreases. This also holds for bacterial growth rates (essentially a collection of chemical reactions). However, when bacterial growth rate () is examined on an Arrhenius plot (log versus 1/T), two linear domains often appear below T opt . The point at which the slope changes is designated the critical temperature (T critical ). The existence of T critical has been reported for eurypsychrophiles, mesophiles, and thermophiles (5,6,9,12,13,15,22,35)....

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“…Furthermore, exposure to low positive temperatures may act as an "adapter" to freezing temperatures, leading, as a possible consequence of the synthesis of specific proteins, to decreased lethality, a phenomenon called cryotolerance (27,34,37).…”

mentioning

confidence: 99%

Differentiation between cold shock proteins and cold acclimation proteins in a mesophilic gram-positive bacterium, Enterococcus faecalis JH2-2

et al. 1997

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Physiological response of Enterococcus faecalis JH2-2 to cold shock: growth at low temperatures and freezing/thawing challenge

Cited by 74 publications

References 31 publications

Effects of six substances on the growth and freeze-drying of Lactobacillus delbrueckii subsp. bulgaricus

Effects of six substances on the growth and freeze-drying of Lactobacillus delbrueckii subsp. bulgaricus

Relationship of Critical Temperature to Macromolecular Synthesis and Growth Yield in Psychrobacter cryopegella

Differentiation between cold shock proteins and cold acclimation proteins in a mesophilic gram-positive bacterium, Enterococcus faecalis JH2-2

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