Effects Of Cold Shock Research Articles

Altering shale permeability by cold shock

The matrix permeability of shale is on the order of nanodarcy (nD), and hydrocarbon recovery from it is economical only after hydraulic fracturing. Another fracturing technique, which is often overlooked, is cryogenic fracturing. This study determines the effects of cold shock on shale permeability by focusing on the sub-100-nm pore throats that control access to a significant fraction of the pore space in the matrix. We extracted shale samples, heated them to mimic various formation burial depths, and shocked them in liquid nitrogen. Subsequently, we measured their capillary pressures. This study presents a conceptual model to shed light on the heterogeneous deformations at a sub-100-μm scale. Also, it uses a network modeling approach to determine the permeability enhancement based on the pore-throat size distributions obtained from the capillary pressure measurements. It demonstrates that cold shock enhances permeability by 20%, significantly lower than the typical values reported in the literature where the effects of subsurface temperature have been neglected. The enhancement depends non-monotonically on the temperature difference applied. Moreover, the results indicate that there may be an optimal scenario to maximize the enhancement that can only be determined experimentally. The reason for the incapability of the purely analytical approach is also discussed.

In Vitro Effects of Charged and Zwitterionic Liposomes on Human Spermatozoa and Supplementation with Liposomes and Chlorogenic Acid during Sperm Freezing.

Semen handling and cryopreservation induce oxidative stress that should be minimized. In this study, human semen was supplemented during cryopreservation with formulations of handmade liposomes and chlorogenic acid (CGA), an antioxidant compound. Zwitterionic (ZL), anionic (AL), and cationic (CL) liposomes were synthesized and characterized. Three aliquots of swim-up-selected sperm were incubated with ZL, AL, and CL (1:10,000), respectively. The percentages of sperm with progressive motility, high mitochondrial membrane potential (MMP; JC-1), double-stranded DNA (dsDNA acridine orange), and acrosome integrity (Pisum sativum agglutinin) were assessed. Then, human semen was frozen using both 1:10,000 ZL and CGA as follows: freezing medium/empty ZL (EL), freezing medium/empty ZL/CGA in the medium (CGA + EL), freezing medium/CGA loaded ZL (CGA), freezing medium (CTR). The same sperm endpoints were evaluated. ZL were the most tolerated and used for semen cryopreservation protocols. All the supplemented samples showed better endpoints versus CTR (p < 0.001). In particular, spermatozoa from the CGA and CGA + EL A samples showed increased motility, dsDNA, and acrosome integrity versus CTR and EL (p < 0.001; motility EL vs. CGA + EL p < 0.05). ZL and CGA can improve post-thaw sperm quality, acting on both cold shock effect management and oxidative stress. These findings open new perspectives on human and animal reproduction.

Effect of cold shock precooling on the physicochemical, physiological properties and volatile profiles of chili peppers during postharvest storage

Cold shock precooling with ice-water mixture (0 ± 2 °C) was innovatively utilized in this study to supposedly improve the postharvest quality of chili pepper fruit during storage at 10 ± 2 °C. The chili peppers were randomly exposed to four different treatment groups being without and with cold shock for 30 min, 60 min and 90 min. Results indicate that cold shock was beneficial to preserve the postharvest quality of chili peppers by observing less weight loss, higher hardness value, better antioxidant capacity and flavor quality during a 0–21 d storage period. After comparison, cold shock treatment for 90 min was determined as the optimal condition. Taken together, we concluded that cold shock can be utilized as a cost-effective and environmentally friendly alternative to alleviate quality deterioration and enhance commercial value of chili peppers during postharvest storage.

In vitro Effects of Cold Shock on the Size and Activity of Nucleated Erythrocytes in Scorpaena porcus (Linnaeus, 1758)

In vitro Effects of Cold Shock on the Size and Activity of Nucleated Erythrocytes in Scorpaena porcus (Linnaeus, 1758)

EFFECTS OF COLD SHOCK ON THE SIZE AND ACTIVITY OF &lt;i&gt;SCORPAENA PORCUS&lt;/i&gt; (LINNAEUS, 1758) NUCLEAR ERYTHROCYTES (&lt;i&gt;IN VITRO&lt;/i&gt; EXPERIMENTS)

The in vitro effect of cold shock on erythrocytes of the benthic scorpionfish Scorpaena porcus L. was studied. The blood samples were exposed to 22°С (control group) and 4°С (experimental group) for 3 hours. Cold shock had no significant impact on erythrocyte scorpionfish vital function. The cells maintained the integrity of cytoplasmic membranes, mitochondrial potential and the level of oxidative processes, that the constant values of Propidium Iodide (PI), Rhodamine 123 (R123) and 2',7'-Dichlorodihydrofluorescein diacetate (DCF-DA) fluorescence levels demonstrated. Main changes referred to erythrocyte shape and nucleus functional activity. Cells gained more roundish shape, nucleus size increased with the growth of the nuclear-cytoplasmic ratio (NCR) and the decrease of fluorescence intensity of the cells labeled with SYBR Green I. It appears to be related to the activation of transcriptomic processes.

Characteristics of Acoustic Emission Response during Granite Splitting after High Temperature-Water Cooling Cycles

In order to investigate the effect of a high temperature-water cooling cycle on the acoustic emission characteristics of the granite splitting process, Brazilian splitting tests were conducted on granite disc specimens treated with high temperature–water cooling (cycle times 1, 5, 10, 15, 20) from 250 to 650 °C. The relationship between the acoustic emission count, cumulative acoustic emission number, amplitude distribution, and the maximum energy of the specimens and temperature as well as the number of hot and cold cycles were investigated, and the relationship between the acoustic emission changes and specimen damage during the splitting of the granite specimens after the high temperature-water cooling cycle was discussed and analyzed. The test results show that the acoustic emission changes in the splitting process of granite disc specimens have obvious hot and cold shock effects, and that the acoustic emission α value and amplitude density of the specimens at the initial stage of splitting show an increasing trend with an increasing number of hot and cold cycles, and the amplitude distribution is more obviously affected by temperature. When the temperature is low and the number of hot and cold cycles is small, the maximum energy value at the peak stress point is larger, and the maximum energy value tends to decrease gradually as the temperature increases and the number of cycles increases.

Liquid storage of stallion spermatozoa – Past, present and future

The ability to store stallion spermatozoa between the events of semen collection and insemination has facilitated improved rates of gain in selective breeding programs by enabling the transport of spermatozoa. While cryopreservation is the only viable means of storing spermatozoa for long intervals, the higher costs and reduced fertility of cryopreserved spermatozoa have led to most breeders opting to use liquid stored spermatozoa. Stallion spermatozoa is commonly cooled during liquid storage (approximately 4–5 °C), and there has been an enormous body of research dedicated to development of protocols and media to facilitate sperm survival including identification of energy sources, antioxidants, pH buffers and toxic metabolite scavengers, along with membrane-stabilising components to reduce deleterious effects of cold shock. Despite these efforts, the upper time limit for cooled sperm storage is ∼ 72 h and there are many stallions whose spermatozoa cannot tolerate the process of cooling. As such, media have been developed to allow spermatozoa to be liquid stored at higher temperatures (15 – 22 °C), and these efforts have led to development of a medium that can effectively store stallion spermatozoa for at least 7 d with no appreciable loss of fertilising capacity. Furthermore, there is an increasing body of research aimed at providing substrates that allow spermatozoa to repair and regenerate during storage, thereby challenging the paradigm that post-ejaculatory sperm damage is irreversible. This review aims to summarize stallion sperm liquid storage strategies and the developments that led to the technologies available today.

Cold shock treatment alleviates chilling injury in peach fruit by regulating antioxidant capacity and membrane lipid metabolism

Abstract Objectives The work intended to reveal the effect of cold shock (CS) treatment on chilling injury (CI), antioxidant capacity, and membrane fatty acid of peach fruit. Materials and methods Peaches were soaked in ice water (0 °C) for 10 min and stored at 5 °C for 28 days for determination, except CI, and then stored for 3 days at 20 °C, only CI was measured. The electrolyte leakage (EL) was measured by conductivity meter. The activities of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, catalase, and peroxidase) and key enzymes of membrane lipid metabolism (phospholipase D, lipase, and lipoxygenase) as well as reactive oxygen species (ROS; O2·– and H2O2) were measured with a spectrophotometer. An ELISA kit and gas chromatography were used to determine membrane lipids and membrane fatty acids. The relative gene expression was measured by real-time polymerase chain reaction analysis. Results The results showed that CS treatment effectively delayed CI, suppressed the increase of EL and malondialdehyde content. Meanwhile, CS-treated fruit exhibited lower level of ROS and higher activities of antioxidant enzymes. Furthermore, CS treatment inhibited the activities as well as the relative gene expression of key enzymes in membrane lipid metabolism. CS-treated fruits maintained higher membrane fatty acid unsaturation and lower phosphatidic acid content. Conclusions These results indicated that CS treatment effectively alleviated CI and maintained the integrity of cell membranes by inducing antioxidant-related enzyme activity and maintaining a higher ratio of unsaturated fatty acids to saturated fatty acids.

How Cold Shock Affects Ploidy Level and Early Ontogenetic Development of the Sterlet, A. ruthenus L.

The objective of the present research was to study the effect of cold shock (3 °C and 6 °C) on fertilized eggs of the sterlet, Acipenser ruthenus L. Cold shock was applied for various durations (30, 60 and 90 min) and the ploidy levels, survival, and genotypes of the treated embryos/larvae were recorded. Analysis of ploidy levels confirmed the presence of diploid, triploid, and mosaic (1n/2n, 2n/3n, and 1n/2n/3n) genotypes in experimental groups, while it was strictly diploid in control groups. Microsatellite genotyping confirmed both the incidence of polyspermy and retention of the 2nd polar body in experimental groups. However, patterns of inheritance in all diploid offspring in experimental and control groups revealed classical Mendelian disomic inheritance. Interestingly, the observed mosaic sterlets had normal morphology and were alive. However, some larvae had abnormal morphology which may be due to haploid syndrome. In all treatment groups (treatments: 3 °C–30 min; 3 °C–60 min; 3 °C–90 min; 6 °C–60 min), where the percentage of polyploid/mosaic larvae were high, the mortality was also high. Whereas, in the control groups (where there were only diploid (2n) larvae), the mortality was relatively low.

Cold shock treatment with oxalic acid could alleviate chilling injury in green bell pepper by enhancing antioxidant enzyme activity and regulating proline metabolism

The effects of cold shock, oxalic acid, and combined cold shock + oxalic acid treatments on chilling injury, antioxidant enzyme activity, and proline metabolism of cold-stored green bell pepper fruit were investigated. The results showed that cold shock, oxalic acid treatment, and their combination significantly reduced chilling injury, inhibited the increase of superoxide radical production, hydrogen peroxide content, malondialdehyde levels, and relative membrane permeability, and increased antioxidant enzyme activity. Furthermore, the treatments promoted the accumulation of proline associated with increase in ∆1-pyrroline-5-carboxylate synthetase and ornithine δ-aminotransferase activities, and decrease in proline dehydrogenase activity. The results indicate that cold shock, oxalic acid, and their combination alleviated chilling injury in green bell pepper fruit by increasing antioxidant enzyme activity and proline accumulation. The combined cold shock + oxalic acid treatment was the most effective method for reducing chilling injury, and therefore has broad future application prospects.

Adaptation of flocculent anammox culture to low temperature by cold shock: long-term response of the microbial population

ABSTRACT Partial nitritation-anammox (PN/A) process will substantially reduce the costs for the removal of nitrogen in the mainstream of municipal sewage. However, one of the mainstream PN/A challenges is to reduce the time necessary for the adaptation of anammox bacteria to lower temperatures in mild climates. In this study, we exposed anammox flocculent culture to cold shocks [35°C → 5°C (8 h) → 15°C] and evaluated long-term cold shock response. Over a post-shock period of 40 d at 15°C, the nitrogen removal rates in the shocked culture were significantly higher compared to control, with maximum rates up to 0.082 and 0.033 kg-N/kg-VSS/d or 0.164 and 0.076 kg-N/m3/d, for shocked culture and control, respectively. In the corresponding semi-batch cycles, the shocked culture was on average 136 ± 101% more active than the control, due to the negative effect of cold shock on side populations and more active anammox cells. Per FISH, Ca. Brocadia anammoxidans and Ca. Scalindua survived the shock and remained present throughout. Thus, both anammox microorganisms seem to respond favourably to cold shocks. In sum, we provide further evidence that cold shocks accelerate the adaptation of anammox to the mainstream of municipal WWTPs. Further, for the first time, we report the long-term adaptive response of anammox to cold shocks.

Experimental Investigation on Physical and Mechanical Properties of Granite Subjected to Cyclic Heating and Liquid Nitrogen Cooling

Cyclic liquid nitrogen (LN2) fracturing is an innovative technology for reservoir stimulation with great potential in geothermal energy exploitation. Understanding of the mechanical responses of high-temperature rock to repetitive LN2 cooling at the laboratory scale is of great relevance to facilitate the field application of cyclic LN2 fracturing. In this work, granite samples were subjected to 0–24 heating–cooling cycles in two manners (i.e., slow heating to 300 °C followed by air cooling or LN2 cooling), and subsequent a series of laboratory tests with the aim of investigating the damage characteristics and mechanisms of rock samples after different heating–cooling cycles. The results concluded that increasing the number of cycles aggravates the internal structural damage of granite, which further deteriorates its physico-mechanical properties. Compared with air cooling, the cold shock effect of LN2 is more capable of facilitating the growth of microcracks within the rock, thereby inducing a more severe initial damage to granite sample. However, the damage of granite is prominent only in the first few cycles, and basically no longer intensified after more than about 12 cycles. This is related to the fact that the increase in micro-defects provides more space for thermal deformations of minerals and reduces the level of thermal stress within the rock. The results in this study are instructive for evaluating the effectiveness of cryogenic fracturing and determining the reasonable number of LN2 fracturing during reservoir stimulation.

Effects of Cold Shock Combined With Salicylic Acid Treatment on Chilling Injury, Energy and Proline Metabolism of Postharvest Cucumber Fruit

Effects of Cold Shock Combined With Salicylic Acid Treatment on Chilling Injury, Energy and Proline Metabolism of Postharvest Cucumber Fruit

Short-term cold stress and heat shock proteins in the crustacean Artemia franciscana.

In their role as molecular chaperones, heat shock proteins (Hsps) mediate protein folding thereby mitigating cellular damage caused by physiological and environmental stress. Nauplii of the crustacean Artemia franciscana respond to heat shock by producing Hsps; however, the effects of cold shock on Hsp levels in A. franciscana have not been investigated previously. The effect of cold shock at 1°C followed by recovery at 27°C on the amounts of ArHsp90, Hsp70, ArHsp40, and ArHsp40-2 mRNA and their respective proteins in A. franciscana nauplii was examined by quantitative PCR (qPCR) and immunoprobing of western blots. The same Hsp mRNAs and proteins were also quantified during incubation of nauplii at their optimal growth temperature of 27°C. qPCR analyses indicated that the abundance of ArHsp90, Hsp70, and ArHsp40 mRNA remained relatively constant during both cold shock and recovery and was not significantly different compared with levels at optimal temperature. Western blotting revealed that ArHsp90, ArHsp40, and ArHsp40-2 were generally below baseline, but at detectable levels during the 6h of cold shock, and persisted in early recovery stages before declining. Hsp70 was the only protein that remained constant in quantity throughout cold shock and recovery. By contrast, all Hsps declined rapidly during 6h when nauplii were incubated continuously at 27°C optimal temperature. Generally, the amounts of ArHsp90, ArHsp40, and ArHsp40-2 were higher during cold shock/recovery than those during continuous incubation at 27°C. Our data support the conclusion that low temperature preserves Hsp levels, making them available to assist in protein repair and recovery after cold shock.

The effects of cold shock on freshwater fish larvae and early-stage juveniles: implications for river management.

Temperature is essential to the maintenance of optimal physiological functioning in aquatic organisms. Fish can manage natural fluctuations in temperature; however, in freshwater ecosystems acute and rapid temperature changes can originate from sources such as large dams and industrial effluents. These rapid temperature changes may induce several physiological and behavioural responses that can result in lethal and sub-lethal consequences. The present study assessed immediate sub-lethal and short-term (10days) lethal responses of three species of Australian freshwater fish larvae and early-stage juveniles to a range of different 'field-relevant' cold shocks (-4, -6, -8 and -10°C). Murray cod (Maccullochella peelii), silver perch (Bidyanus bidyanus) and golden perch (Macquaria ambigua) were tested at two age groups to elucidate the interaction between ontogeny and sensitivity to cold shock. Cold shock caused mortality and reductions in swimming ability (time to exhaustion and lines crossed) in all species of fish at both age groups. Sensitivity was correlated to the magnitude of cold shock; a 10°C drop in temperature caused the highest mortalities. Ontogeny interacted with the severity of cold shock; the younger fish experienced higher mortalities and greater impairment to swimming ability. This study demonstrates the potential lethal and sub-lethal impacts of cold shock on freshwater fish at a critical life-history stage. Understanding the impacts of cold shock will aid management of freshwater ecosystems for the benefit of fish populations, with the current study identifying critical life stages to be considered in remediation and guiding thresholds necessary to reduce the impact of cold shock on native fish populations.

The effect of water clover (Marsilea crenata) extract addition in egg yolk and skim milk extender on frozen goat semen quality

Frozen semen has of longer storage time, but the effect of cold shock during processing reduces the semen quality. Antioxidants in water clover extract are expected to be able to maintain the quality of frozen semen. The study aimed to evaluate the effect of addition of water clover extract (WCE) in the base semen dilution (egg yolk-skim milk) to the quality of post-thawing semen. The material used in this study was goat semen. There were four treatments: T0 as control (base dilution + 0% WCE), T1 (base dilution +1% WCE), T2 (base dilution +3% WCE), and T3 (base dilution +5% WCE), with ten replications each.. This study used a randomized completed design, ANOVA, and continued with Duncan’s Multiple Range Test. The results showed that the addition of water clover extract to egg yolk skim extender had a significant effect (P <0.05) on the motility of individual spermatozoa, viability and membrane integrity, but didn’t have a significant effect (P> 0.05) on sperm abnormalities. The research concludes that the addition of 3% water clover extract in egg yolk skim milk extender was the best concentration to maintain the quality of frozen goat semen.

Effects of cold shock and warming rate on boar sperm

Effects of cold shock and warming rate on boar sperm

Improving homology-directed repair efficiency in human stem cells.

The generation of induced pluripotent stem cell models of human disease requires efficient modification of one or both alleles depending on dominant or recessive inheritance of the disease. To faithfully recapitulate many disease variants, the introduction of a single base change is required. The introduction of additional silent mutations designed to prevent re-cutting of the modified allele by Cas9 is not an optimal strategy, particularly for non-coding variants. Here, we developed an improved protocol for efficient engineering of single nucleotide variants in human iPS cells. Using a fluorescent BFP->GFP assay to monitor the incorporation of a single base pair change, we optimized the protocol to achieve HDR in 70% of unselected human iPS cells. The additive effects of cold shock, a small molecule enhancer of HDR and chemically modified ssODN dramatically shift the bias of repair in favor of HDR, resulting in a seven-fold higher ratio of HDR to NHEJ from 0.5 to 3.7.

In Vitro demonstration of Pseudomonas Growth and Phenotypic Examinations of the Cells Under Cold Shock

The present study attempted to detect the effect of cold shock on Pseudomonas aeruginosa, P. fluorescence, and P. putida; to deduce the culturable cells, the possible dead cells and viable but non-culturable (VBNC) cells; i. e., living but not capable of forming the colony forming units (CFUs) at 0 oC and at 4 oC. Estimation of VBNC at low temperature was performed by deducting the number of culturable cells (formed as CFUs) at 0 °C and at 4 oC from the culturable cells at 37 °C. Maximum culturable cells (around 106 CFU/ ml) appeared at 24-48 hours, and after that, a gradual decline in the numbers of the culturable cells was observed. A minor but significant growth reduction was noticed in Minimal Broth compared to that in Luria Broth. Significant reduction in the culturable cells of all three strains was noticed under cold shock. However, a fraction of the population of each strain was observed to survive under cold stress. Interestingly while the number of culturable cells decreased in course of time under cold shock, the number of VBNC apparently seemed to be constant or to be increased. A comparatively lower number of VBNC was noticed under cold shock in case of P. putida which in turn affected culturability at ambient temperature.&#x0D; Bangladesh J Microbiol, Volume 34 Number 2 December 2017, pp 119-124

Contribution of the cold shock protein CspA to virulence in Xanthomonas oryzae pv. oryzae.

Summary Xanthomonas oryzae pv. oryzae (Xoo) causes a damaging bacterial leaf blight disease in rice. Cold shock proteins (Csps) are highly conserved nucleic acid‐binding proteins present in various bacterial genera, but relatively little is known about their functions in Xanthomonas. Herein, we identified four Csps (CspA–CspD) in the Xoo PXO99A strain. Deletion of cspA decreased cold adaptation and a few known pathogenic factors, including bacterial pathogenicity, biofilm formation and polysaccharide production. Furthermore, we performed transcriptomic and chromosome immunoprecipitation (ChIP) experiments to identify direct targets of CspA and to determine its DNA‐binding sequence. Integrative data analysis revealed that CspA directly regulates two genes, PXO_RS11830 and PXO_RS01060, by binding to a conserved CCAAT sequence in the promoter region. We generated single‐deletion mutants of each gene and the results indicate that both are responsible for Xanthomonas pathogenicity. In addition, quantitative real‐time polymerase chain reaction and western blotting showed that CspA suppressed the expression of its direct targets. In summary, our study clarifies the characteristics of Csps in Xanthomonas and greatly advances our understanding of the mechanisms underlying the contribution of CspA to bacterial virulence.