The survival of Escherichia coli from freeze–thaw damage: permeability barrier damage and viability

1975 ◽  
Vol 21 (11) ◽  
pp. 1724-1732 ◽  
Author(s):  
Peter H. Calcott ◽  
Robert A. MacLeod
Keyword(s):  
Escherichia Coli ◽  
Cooling Rate ◽  
Permeability Barrier ◽  
Freezing And Thawing ◽  
Slow Cooling ◽  
Cooling Rates ◽  
Rate Range ◽  
Permeability Damage ◽  
Extent Of Damage ◽  
Glucose 6 Phosphate Dehydrogenase

The effect of cooling rate and subsequent warming rate on survival of lactose-limited Escherichia coli was investigated. As previously reported, in the slow cooling rate range, a peak of survival was noted at 8 °C/min with survival decreasing as the cooling rate was increased or decreased from this value. Minimal survival was noted at 100 °C/min; increasing the cooling rate above 100 °C/min increased survival. At cooling rates greater than 200 °C/min, the survival became dependent on subsequent warming rates.Permeability damage, as measured by release of UV-absorbing material, potassium and β-galactosidase, and increased accessibility of glucose-6-phosphate dehydrogenase to its substrates, was dependent on the cooling rate when cells were frozen in either water or saline. For cooling rates less than about 8 °C/min, there was minimal permeability damage to cells frozen in water. However, at rates greater than this value, damage and viability were related; the lower the viability the more the damage to the permeability barrier. The relationship was strengthened by the observations that protectants which increased survival reduced damage as well and that at ultrarapid cooling rates where survivals were dependent on warming rates, the extent of damage was likewise dependent on the warming rate.Saline frozen cells were damaged by freezing and thawing more than comparable water-frozen cells over the whole cooling rate range. At cooling rates less than 8 °C/min, frozen in water, permeability damage of cells frozen in saline increased as the cooling rate decreased. As the cooling rate was increased from 8 °C/min, the damage increased as viability decreased.The relevance of these findings to the two-factor hypothesis of cell death is discussed.

scholarly journals Thermal stress, cooling-rate and fictive temperature of silicate melts

2021 ◽  
Vol 176 (10) ◽  
Author(s):  
Sharon L. Webb
Keyword(s):  
Heat Capacity ◽  
Cooling Rate ◽  
Heating Rate ◽  
Calibration Curve ◽  
Silicate Melts ◽  
Internal Stresses ◽  
Heating Rates ◽  
Fictive Temperature ◽  
Slow Cooling ◽  
Cooling Rates

AbstractThe unknown cooling-rate history of natural silicate melts can be investigated using differential scanning heat capacity measurements together with the limiting fictive temperature analysis calculation. There are a range of processes occurring during cooling and re-heating of natural samples which influence the calculation of the limiting fictive temperature and, therefore, the calculated cooling-rate of the sample. These processes occur at the extremes of slow cooling and fast quenching. The annealing of a sample at a temperature below the glass transition temperature upon cooling results in the subsequent determination of cooling-rates which are up to orders of magnitude too low. In contrast, the internal stresses associated with the faster cooling of obsidian in air result in an added exothermic signal in the heat capacity trace which results in an overestimation of cooling-rate. To calculate cooling-rate of glass using the fictive temperature method, it is necessary to create a calibration curve determined using known cooling- and heating-rates. The calculated unknown cooling-rate of the sample is affected by the magnitude of mismatch between the original cooling-rate and the laboratory heating-rate when using the matched cooling-/heating-rate method to derive a fictive temperature/cooling-rate calibration curve. Cooling-rates slower than the laboratory heating-rate will be overestimated, while cooling-rates faster than the laboratory heating-rate are underestimated. Each of these sources of error in the calculation of cooling-rate of glass materials—annealing, stress release and matched cooling/heating-rate calibration—can affect the calculated cooling-rate by factor of 10 or more.

116 IMPROVED SURVIVAL BY CRYOPRESERVING RHESUS MACAQUE (MACACA MULATTA) SPERMATOZOA WITH DIRECTIONAL FREEZING TECHNIQUE

2010 ◽  
Vol 22 (1) ◽  
pp. 217 ◽  
Author(s):  
W. Si ◽  
Y. Lu ◽  
X. He ◽  
S. Ji ◽  
Y. Niu ◽  
...  
Keyword(s):  
Rhesus Monkey ◽  
Cooling Rate ◽  
Sperm Motility ◽  
Genetically Engineered ◽  
Human Diseases ◽  
Slow Cooling ◽  
Cooling Rates ◽  
Important Species ◽  
Directional Freezing ◽  
Acrosomal Integrity

A significant increase in nonhuman primate models of human diseases will be expected in the near future since the successes in production of genetically engineered rhesus monkey models of human diseases. Sperm banking can provide an effective way to preserve valuable genetic resources. Our objective was to (1) develop a protocol using directional freezing technique (DFT) for rhesus monkey spermatozoa cryopreservation, which allows precise control of the velocity and the morphology of the ice-front propagation by transferring the tubes loaded with 2 mL sperm samples at a controllable velocity through two separate chambers with controllable temperature settings, and (2) achieve survival rate that was higher than that achieved with conventional freezing technique (CFT), by which sperm samples were cryopreserved in 0.25 mL straws with liquid nitrogen vapor in a styrofoam box. Sperm motility, acrosomal integrity, and in vitro fertilization (IVF) assay were used to assess the function of frozen-thawed spermatozoa. Data were analyzed by ANOVA and Fisher protected LSD test. Experiment 1 was aimed at optimizing the cooling rate using DFT. Tubes were frozen using the multi-thermal gradient freezing device (MTG 516, Harmony CryoCareTM, IMT Ltd.) at fast (16°C/min), medium (12°C/min), and slow (7°C/min) cooling rates, which corresponded to the transferring velocities (2.5, 1.5, and 0.5 mm s-1, respectively). The results showed that spermatozoa frozen at fast and medium cooling rates showed significantly higher frozen-thawed motility than those frozen at slow cooling rate (61% and 59% v. 50%, P < 0.05). However, no difference was observed on sperm acrosomal integrity among the experimental groups (84, 80, and 78%, respectively, P > 0.05). The purposes of Experiment 2 were determined to examine if using DFT at the optimized cooling rate (12°C/min) can improve the cryo-survival of rhesus monkey spermatozoa compared with CFT. Our results showed that spermatozoa cryopreserved by using DFT achieved significantly higher frozen-thawed sperm motility that those cryopreserved by using CFT (64 v. 54%, P < 0.05). However, no difference was observed on acrosomal integrity between spermatozoa cryopreserved by DFT and CFT (84 and 83%, respectively; P > 0.05). The function of spermatozoa cryopreserved by using DFT was further evaluated by IVF. Females were treated with rhFSH twice-daily for 8 days after the onset of menses and following a treatment of hCG injection on Day 9. Cumulus-oocyte complexes were collected by laparoscopic follicular aspiration 32 h later. Of the inseminated oocytes, 79% were fertilized and 90 and 53% of the resulting zygotes developed into 2-cell and blastocysts, respectively. The fertilization rate was lower and the blastocyst rate was slightly higher than our previous report when fresh spermatozoa were used for IVF (94 and 52%, respectively). Our results indicate that spermatozoa of rhesus monkeys can be effectively cryopreserved using DFT in large volume. This finding provided a new and effective way for genetics preservation purposes in this important species.

Influence of Cooling Rates on Phase Transitions of Bent-Core Liquid Crystal 1,3-Phenylene-bis[4-(hexylcarboyloxyl)benzylideneamine]

2010 ◽  
Vol 428-429 ◽  
pp. 247-250 ◽  
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transitions ◽  
Liquid Crystal ◽  
Optical Microscopy ◽  
Cooling Rate ◽  
Scanning Calorimetry ◽  
Slow Cooling ◽  
Cooling Rates ◽  
Polarized Optical Microscopy ◽  
Fast Cooling

The influence of cooling rate on the phase transitions of a three-benzene-ring containing bent-core liquid crystal 1,3-phenylene-bis[4-(hexylcarboyloxyl)benzylideneamine] has been investigated by means of differential scanning calorimetry and polarized optical microscopy. Our results show that the cooling rates in the second cooling run pose significant effects on the phase transitions of the bent-core liquid crystal despite the cooling rates in the first cooling run pose little effects on the phase transitions. In the second cooling run, the banana phases survived only when the cooling rates were in the range of 14~15oC/min whereas both slow cooling rates which were less than 13oC/min and fast cooling rates which were higher than 16oC/min made the banana phases disappeared.

Achieving the Dual Phase Structure in Low Alloyed Steel with Slow Cooling Rate

2008 ◽  
Vol 575-578 ◽  
pp. 1117-1122
Author(s):  
Tarja Jäppinen ◽  
Seppo Kivivuori
Keyword(s):  
Cooling Rate ◽  
Phase Structure ◽  
Steel Wire ◽  
Optical Microscope ◽  
Carbon Steels ◽  
Alloying Elements ◽  
Dual Phase ◽  
Low Carbon ◽  
Slow Cooling ◽  
Cooling Rates

In steel wire processing it is difficult to reach a homogenous structure throughout the cross-section of the wire particularly in greater diameters. One alternative for producing a homogenous structure is to find a cooling path with a wide transformation temperature range. Fully austenite steel wire rolled at high temperatures can be decomposed into ferritic-martensitic dual phase structure using relatively slow cooling rates. Test materials were low alloyed low carbon steels with variations in alloying elements. Gleeble-1500 thermomechanical simulator was utilised to study the effect of cooling rate on decomposition of austenite after deformation. The microstructures were studied with an optical microscope. In certain low alloyed steels slow cooling rates eliminate the bainite transformation and instead martensite is formed. The final microstructure depends mainly on the carbon content but also on the amount of other alloying elements and their effects on the austenite phase.

Validation of a Simple Two-Point Method To Assess Restaurant Compliance with Food Code Cooling Rates

2020 ◽  
Vol 84 (1) ◽  
pp. 6-13
Author(s):  
MATTHEW J. IGO ◽  
NICOLE HEDEEN ◽  
DONALD W. SCHAFFNER
Keyword(s):  
Cooling Rate ◽  
Screening Tool ◽  
Point Method ◽  
Cooling Curves ◽  
Simple Linear Regression ◽  
Point Model ◽  
Slow Cooling ◽  
Cooling Rates ◽  
Novel Method ◽  
Almost All

ABSTRACT Outbreaks from improperly cooled foods continue to occur despite clearly described Food Code cooling guidelines. It is difficult for regulators to enforce these guidelines because they are typically in an establishment for less than the 6 h needed to document proper cooling. Prior research proposed using a novel method to estimate cooling rates based on two time-temperature points, but this method has not yet been validated. Time-temperature profiles of 29 different foods were collected in 25 different restaurants during cooling. Cooling curves were divided into two categories: typical (21 foods) and atypical (eight foods) prior to further analysis. Analysis of the typical cooling curves used simple linear regression to calculate cooling rates. The atypical cooling profiles were studied using Monte Carlo simulations of the cooling rate. Almost all linearized typical cooling curves had high (&gt;0.90) R2 values. Six foods with typical cooling profiles that did not pass Food Code cooling times were correctly identified by the two-point model as having slow cooling rates. Three foods that did not pass Food Code cooling times were identified by the two-point model as having marginal cooling rates. Ten of 12 foods identified by the two-point model as having acceptable cooling rates met Food Code cooling times. Most (six of eight) foods that were considered to have atypical cooling curves failed to meet the Food Code cooling times. The two-point model was also able to determine whether these foods would fail based on Food Code guidelines depending upon the simulation criteria used. Our data show that food depth has a strong influence on cooling rate. Containers with a food depth ≥7.6 cm (3 in.) were more likely to have cooling rates slower than the U.S. Food and Drug Administration Model Food Code cooling rate. This analysis shows that the two-point method can be a useful screening tool to identify potential cooling rate problems during a routine restaurant inspection visit. HIGHLIGHTS

Improved Post-Thaw Viability and In Vitro Functionality of Peripheral Blood Hematopoietic Progenitor Cells after Cryopreservation with a Theoretically Optimized Freezing Curve.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1222-1222
Author(s):  
Marloes R. Tijssen ◽  
Henri Woelders ◽  
Ada de Vries-van Rossen ◽  
C. Ellen Van der Schoot ◽  
Carlijn Voermans ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Peripheral Blood ◽  
Cell Types ◽  
Subzero Temperature ◽  
Specific Cell ◽  
Freezing And Thawing ◽  
Cooling Rates ◽  
Cd34 Cells ◽  
Non Linear ◽  
Freezing Curve

Abstract Current methods for the cryopreservation of peripheral blood stem cell transplants (PBSCTs) have been developed empirically. Although the use of cryopreserved PBSCTs is successful and usually leads to rapid hematopoietic recovery, the freeze-thawing process is known to induce a significant amount of cell death. Furthermore, the infusion of DMSO, which is used to protect the cells against damage induced by freezing, can cause morbidity. Freezing methods may be improved by using a fundamental cryobiological approach, addressing the putative causes of cell injury during freezing and thawing. Different cell types may have different optimal cooling rates. Cooling rates above this optimum may cause ‘fast cooling damage’, e.g. by lethal intracellular ice formation, while cooling rates below the optimum may lead to ‘slow cooling damage’, These cryoinjuries relate to the osmotic changes during freezing and thawing, and the resulting fluxes of water and cryoprotectant across the cell membrane. Mathematic modeling of these osmotic events can be used to predict the optimal cooling rates for specific cell types. Woelders and Chaveiro* have developed a model that calculates the ‘compromise’ cooling rate for every subzero temperature, resulting in non-linear freezing curves. In the present study, this model was applied to predict ‘optimal’ freezing curves for PBSCTs with 10% and 5% DMSO, respectively, using values for the membrane permeability coefficients and related parameters as published earlier for cord blood HPCs. These predicted curves were tested empirically and compared to the presently used standard linear freezing curve. CD34+ selected and unselected PBSCs were cryopreserved using the standard or the new freezing curves. Post-thaw quality was evaluated by cell viability, CFU-GM formation and megakaryocyte outgrowth. With 10% DMSO, the use of the predicted optimal freezing curve compared to the currently used freezing curve resulted in increased post-thaw viability of CD34+ cells (mean±SEM; 78.4%±6.6% versus 72.0%±6.1% for unselected CD34+ cells and 92.0%±0.6% versus 83.9%±2.5% [p<0.01] for selected CD34+ cells), colony formation (40.7%±8.8% versus 30.1%±7.9% [p<0.01] for unselected CD34+ cells and 102.6%±8.0% versus 90.1%±11.9% for selected CD34+ cells), and megakaryocyte outgrowth (6.0±0.7 versus 3.9±0.6 [p<0.01] CD41+ MKs per seeded selected CD34+ cell). Also lowering the DMSO concentration to 5% resulted in improved post-thaw viability and functionality, comparable to the results obtained with 10% DMSO and the predicted optimal freezing curve. The results obtained with 5% DMSO were not improved by using the theoretically optimized freezing curve, suggesting that the cooling rate of the theoretically predicted curve for 5% DMSO may have been too high. Indeed preliminary experiments with a slightly slower non-linear freezing rate suggest that further improvement is possible. Our results indicate that the current cryopreservation method for PBSCT can be improved by applying theoretically optimized freezing curves. Infusion of less DMSO and more viable cells will likely improve the outcome of PBSCT. * Woelders and Chaveiro, Cryobiology 2004, 49; 258–271

Survival of Escherichia coli from freeze–thaw damage: a theoretical and practical study

1974 ◽  
Vol 20 (5) ◽  
pp. 671-681 ◽  
Author(s):  
Peter H. Calcott ◽  
Robert A. MacLeod
Keyword(s):  
Escherichia Coli ◽  
Cooling Rate ◽  
Tween 80 ◽  
Cell Types ◽  
Distilled Water ◽  
Cell Water ◽  
Survival Curves ◽  
Cooling Rates ◽  
Freeze Thaw ◽  
Ionic Detergent

The effect of cooling and warming rates on the cryosurvival of chemostat populations of Escherichia coli was investigated. Survival curves were obtained which were similar in shape to those obtained by others for other cell types, with saline always a more lethal environment than distilled water.For organisms frozen in either distilled water or saline, as the cooling rate was increased survival increased to a maximum at 6 C/min, decreased to a minimum at 100 C/min, and then continued to increase as the cooling rate was increased to ultrarapid rates (about 6000 C/min). At these ultrarapid rates of cooling but not at lower rates, increasing the rate of warming enhanced survival; slow warming rates were detrimental to survival and eliminated the increase in survival associated with these cooling rates. Solution of a theoretical equation predicted that supercooling of cell water, and thus the likelihood of internal freezing, should increase as the cooling rate was increased from 3.5 to 350 C/min. This increase in probability of internal freezing was paralleled by a decrease in viability of cells as the cooling rate was increased from 6 to 100 C/min.The effectiveness of three protectants was investigated over the whole cooling rate range. Glycerol or sucrose added to suspensions of cells in distilled water protected over the whole range; but at lower cooling rates (less than 6 C/min) they did so with an altered stoichiometry. Sucrose protected organisms frozen in saline and Tween 80, a non-ionic detergent, protected organisms frozen either in saline or distilled water from rapid or ultrarapid cooling only. The evidence supports a two-factor hypothesis to explain cryoinjury.

Vitrification Fulfills its Promise as an Approach to Reducing Freeze-Induced Injury in a Multicellular Tissue

1999 ◽  
Author(s):  
Michael J. Taylor ◽  
Ying C. Song ◽  
Bijan S. Kheirabadi ◽  
Fred G. Lightfoot ◽  
Kelvin G. M. Brockbank
Keyword(s):  
Cooling Rate ◽  
Vascular Tissue ◽  
Contractile Function ◽  
Supercooled Liquid ◽  
Freezing And Thawing ◽  
Tissue Water ◽  
Slow Cooling ◽  
Destructive Effect ◽  
Commercial Method

Abstract The destructive effect of extracellular ice formation in organized multicellular tissues is known to be a principal reason why conventional techniques of cryopreservation fail to provide effective protection during freezing. Avoidance of ice during cooling can physically be achieved by vitrification, which is the amorphous solidification of a supercooled liquid by adjusting the solute composition and cooling rate such that nucleation and growth of ice crystals is prevented. In principal a biological system can be stabilized in the glassy (vitreous) state without the inherent problems associated with crystallization and so-called solution effects injury that arise from the increased concentration of solutes due to removal of water as ice. This study was designed to evaluate a vitrification approach to storing a vascular tissue model (rabbit jugular vein) compared with a standard commercial method used clinically and employing slow cooling (l°C/min) with dimethylsulfoxide (DMSO) as the cryoprotective agent (CPA). A baseline vitrification medium (designated VS55) was used to replace at least 50% of the tissue water with a combination of CPAs. and vitrification was achieved using a relatively high cooling rate (&gt; 40°C/min). After rewarming and removal of the CPAs. contractility of the blood vessel segments was evaluated in vitro using standard physiological response tests to a panel of reagents. The maximum contractions achieved in vitrified vessels were all greater than 80% of fresh matched controls with similar drug sensitivities. In contrast, frozen/thawed vessels exhibited maximal contractions below 25% of fresh matched controls with concomitant decreases in drug sensitivity. This study clearly demonstrates a significant benefit of vitrification compared with conventional freezing and thawing for preserving smooth muscle contractile function of preserved blood vessels. Vitrification may prove to be an effective way to minimize the deleterious effects of freezing and thawing in cryopreserved tissues, or engineered tissue constructs.

Effect of Cooling Rate on Glass Formation for Some Oxynitride Glasses

2007 ◽  
Vol 554 ◽  
pp. 25-30 ◽  
Author(s):  
Wynette Redington ◽  
Murt Redington ◽  
Stuart Hampshire
Keyword(s):  
Cooling Rate ◽  
Glass Formation ◽  
Resistance Furnace ◽  
Slow Cooling ◽  
Cooling Rates ◽  
X Ray ◽  
Glass Forming ◽  
Wide Range ◽  
Fast Cooling ◽  
Nd Systems

Rapid cooling rates and quenching have traditionally been associated with glass formation. Hampshire et al. [1] investigated oxynitride glasses cooled in a tungsten resistance furnace at approximately 200oC/min and found that fast cooling rates were only important near the limits of the glass-forming region. In the current work on various M-Si-Al-O-N (M=Y, La, Yb, Nd) systems, it was found that even at a relatively slow cooling rate glass formation was still possible for a wide range of compositions. Different cooling rates were investigated to determine the minimum cooling rate at which a glass will form. Quantitative X-ray analysis of melted compositions indicated the relative amounts of amorphous phase and crystalline phase.

Survival of Escherichia coli from freeze–thaw damage: influence of nutritional status and growth rate

1974 ◽  
Vol 20 (5) ◽  
pp. 683-689 ◽  
Author(s):  
Peter H. Calcott ◽  
Robert A. MacLeod
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Nutritional Status ◽  
Cooling Rate ◽  
Growth Rates ◽  
Upward Trend ◽  
Rate Range ◽  
Carbon And Nitrogen ◽  
Freeze Thaw

The influence of nutritional status and growth rate on the cryosurvival of Escherichia coli was investigated. Organisms grown at rates between 0.1 and 0.6 h−1, under carbon- or nitrogen-limiting conditions all showed a basically similar cooling rate – survival profile; a peak of survival was noted in the lower cooling rate range (less than 100 C/min), a trough of minimum survival at 100 C/min, and increased survival as the cooling rate was increased to ultrarapid rates. Carbon-limited organisms showed a shift of the peak from 6 C/min for slowly grown organisms (D = 0.11) to 40 C/min at higher growth rates (D = 0.60 h−1); their survival at these peaks also showed a slightly upward trend. Nitrogen-limited organisms showed a similar trend of a shifting of the peak of survival. However, as the growth rate was increased, survival at this peak, and at other regions, decreased. For carbon-limited organisms, above 100 C/min, survival was growth rate independent, unlike nitrogen-limited organisms, which exhibited lower survivals as the cooling rate was increased in the ultrarapid range. The survival of both carbon-and nitrogen-limited organisms at the peak of survival showed a correlation with their carbohydrate and protein contents. The relevance of these findings is discussed.

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