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Binding of the bacterial Rho helicase to nascent transcripts triggers Rho-dependent transcription termination (RDTT) in response to cellular signals that modulate mRNA structure and accessibility of Rho utilization (Rut) sites. Despite the impact of temperature on RNA structure, RDTT was never linked to the bacterial response to temperature shifts. We show that Rho is a central player in the cold-shock response (CSR), challenging the current view that CSR is primarily a posttranscriptional program. We identify Rut sites in 5′-untranslated regions of key CSR genes/operons (cspA , cspB , cspG , and nsrR - rnr - yjfHI) that trigger premature RDTT at 37°C but not at 15°C. High concentrations of RNA chaperone CspA or nucleotide changes in the cspA mRNA leader reduce RDTT efficiency, revealing how RNA restructuring directs Rho to activate CSR genes during the cold shock and to silence them during cold acclimation. These findings establish a paradigm for how RNA thermosensors can modulate gene expression. [Display omitted] • Temperature-induced restructuring of nascent mRNA governs binding by the Rho factor • Rho-dependent transcription terminators regulate major cold-shock genes • The transcription terminators switch off at low temperature • The RNA chaperone CspA reactivates termination during cold acclimation Delaleau et al. challenge the current view that the bacterial response to cold shock is primarily a posttranscriptional program. The authors unveil an additional regulatory layer whereby low temperature prevents Rho-dependent transcription attenuation of cold-shock genes. The resulting accumulation of RNA chaperone protein CspA helps restore attenuation. [ABSTRACT FROM AUTHOR]

Background: Gastric ulcer is among the most serious stomach disorder universally. Several effective drugs are employed in the management of this disease, although there have been adverse effects in some cases. The aim of this study was to investigate the effect of nortriptyline to protect against gastric lesions, induced by indomethacin or cold-stress in rats. Methods: Gastric lesions were induced by oral indomethacin (30 mg/kg) or cold-shock at 2-4°C. Animals were pre-treated with 5, 10 or 20 mg/kg nortriptyline. After 4hr of exposure to indomethacin or cold shock, the stomach was removed for histological examinations and the levels of enzymatic and non-enzymatic oxidative stress markers were determined in the tissue samples. Results: The results showed that nortriptyline at 20 mg/kg significantly restored the activity of the oxidative stress markers, such as Superoxide Dismutase (SOD) and Catalase (CAT) enzymes. It also decreased the tissue Malondialdehyde (MDA) concentration. In addition, nortriptyline at 20 mg/kg, ameliorated the gastric tissue damages caused by indomethacin or the cold shock. Conclusion: The results suggest that improvement in gastric mucosal lesions can be mediated by nortriptyline pretreatment, which is likely due to its antioxidant property.

Background and Objectives: Staphylococcus aureus is a main human pathogen that causes a variety of chronic to persistent infections. Across the diverse factors of pathogenesis in bacteria, Toxin-Antitoxin (TA) systems can be considered as an antibacterial target due to their involvement in cellular physiology counting stress responses. Here, the expression of TA system genes and ClpP protease was investigated under the thermal and oxidative conditions in S. aureus strains. Materials and Methods: The colony-forming unit (CFU) was used to determine the effects of thermal and oxidative stresses on bacterial survival. Moreover, the expressions of TA system genes in S. aureus strains were evaluated 30 min and 1 h after thermal and oxidative stresses, respectively, by quantitative reverse transcriptase real-time PCR (qRT-PCR). Results: The cell viability was constant across thermal stress while oxidative stress induction showed a significantly decrease in the growth of Methicillin-Resistant S. aureus (MRSA) strain. Based on the qRT-PCR results, the expression of mazF gene increased under both thermal and oxidative stresses in the MRSA strain. Conclusion: A putative TA system (namely immA/irrA) most likely has a role under the stress condition of S. aureus. The MRSA strain responds to stress by shifting the expression level of TA genes that has diverse effects on the survival of the pathogen due to the stress conditions. The TA systems may be introduced as potential targets for antibacterial treatment.

Background and Objectives: Staphylococcus aureus is a main human pathogen that causes a variety of chronic to persistent infections. Across the diverse factors of pathogenesis in bacteria, Toxin-Antitoxin (TA) systems can be considered as an antibacterial target due to their involvement in cellular physiology counting stress responses. Here, the expression of TA system genes and ClpP protease was investigated under the thermal and oxidative conditions in S. aureus strains. Materials and Methods: The colony-forming unit (CFU) was used to determine the effects of thermal and oxidative stresses on bacterial survival. Moreover, the expressions of TA system genes in S. aureus strains were evaluated 30 min and 1 h after thermal and oxidative stresses, respectively, by quantitative reverse transcriptase real-time PCR (qRT-PCR). Results: The cell viability was constant across thermal stress while oxidative stress induction showed a significantly decrease in the growth of Methicillin-Resistant S. aureus (MRSA) strain. Based on the qRT-PCR results, the expression of mazF gene increased under both thermal and oxidative stresses in the MRSA strain. Conclusion: A putative TA system (namely immA/irrA) most likely has a role under the stress condition of S. aureus. The MRSA strain responds to stress by shifting the expression level of TA genes that has diverse effects on the survival of the pathogen due to the stress conditions. The TA systems may be introduced as potential targets for antibacterial treatment. [ABSTRACT FROM AUTHOR]

Background: Gastric ulcer is among the most serious stomach disorder universally. Several effective drugs are employed in the management of this disease, although there have been adverse effects in some cases. The aim of this study was to investigate the effect of nortriptyline to protect against gastric lesions, induced by indomethacin or cold-stress in rats. Methods: Gastric lesions were induced by oral indomethacin (30 mg/kg) or cold-shock at 2-4°C. Animals were pre-treated with 5, 10 or 20 mg/kg nortriptyline. After 4hr of exposure to indomethacin or cold shock, the stomach was removed for histological examinations and the levels of enzymatic and non-enzymatic oxidative stress markers were determined in the tissue samples. Results: The results showed that nortriptyline at 20 mg/kg significantly restored the activity of the oxidative stress markers, such as Superoxide Dismutase (SOD) and Catalase (CAT) enzymes. It also decreased the tissue Malondialdehyde (MDA) concentration. In addition, nortriptyline at 20 mg/kg, ameliorated the gastric tissue damages caused by indomethacin or the cold shock. Conclusion: The results suggest that improvement in gastric mucosal lesions can be mediated by nortriptyline pretreatment, which is likely due to its antioxidant property. [ABSTRACT FROM AUTHOR]

Cold water immersion (CWI) may provide benefits for physical and mental health. Our purpose was to investigate the effects of an acute bout of CWI on vascular shear stress and affect (positive and negative). Sixteen healthy adults (age: 23 ± 4 y; (9 self-reported men and 7 self-reported women) completed one 15-min bout of CWI (10 °C). Self-reported affect (positive and negative) was assessed at pre-CWI (Pre), 30-min post-immersion, and 180-min post-immersion in all participants. Brachial artery diameter and blood velocity were measured (Doppler ultrasound) at Pre, after 1-min and 15-min of CWI, and 30-min post-immersion (n = 8). Total, antegrade, and retrograde shear stress, oscillatory shear index (OSI), and forearm vascular conductance (FVC) were calculated. Venous blood samples were collected at Pre, after 1-min and 15-min of CWI, 30-min post-immersion, and 180-min post-immersion (n = 8) to quantify serum β -endorphins and cortisol. Data were analyzed using a one-way ANOVA with Fisher's least significance difference and compared to Pre. Positive affect did not change (ANOVA p = 0.450) but negative affect was lower at 180-min post-immersion (p < 0.001). FVC was reduced at 15-min of CWI and 30-min post-immersion (p < 0.020). Total and antegrade shear and OSI were reduced at 30-min post-immersion (p < 0.040) but there were no differences in retrograde shear (ANOVA p = 0.134). β -endorphins did not change throughout the trial (ANOVA p = 0.321). Cortisol was lower at 180-min post-immersion (p = 0.014). An acute bout of CWI minimally affects shear stress patterns but may benefit mental health by reducing negative feelings and cortisol levels. • Cold water immersion had a minimal effect on peripheral shear stress patterns. • β-endorphins and positive mood did not change after cold water immersion. • Cortisol and negative mood were lower 180 min after cold water immersion. [ABSTRACT FROM AUTHOR]

The aim of this study was to induce the cold‐inducible RNA‐binding protein (CIRBP) expression on cumulus–oocyte complexes (COCs) through exposure to a sub‐lethal cold shock and determine the effects of hypothermic temperatures during the in vitro maturation of bovine oocytes. Nuclear maturation, cortical granule redistribution and identification of cold‐inducible RNA‐binding protein (CIRBP) were assessed after 24 hr of in vitro maturation of control (38.5°C) and cold‐stressed oocytes (33.5°C). The presence of CIRBP was assessed by Western blot in COCs or denuded oocytes and their respective cumulus cells. Based on the odds ratio, cold‐stressed oocytes presented higher abnormal cytoplasmic distribution of cortical granules and nuclear maturation than the control group. Although CIRBP was detected in both control and cold‐stressed groups, cold‐stressed COCs had 2.17 times more expression of CIRBP than control COCs. However, when denuded oocytes and cumulus cells were assessed separately, CIRBP only was detected in cumulus cells in both groups. In conclusion, cold shock induced CIRBP expression, but it negatively affected nuclear maturation and cortical granule distribution of bovine oocytes. Moreover, the expression of CIRBP was only identified in cumulus cells but not in oocytes. [ABSTRACT FROM AUTHOR]

Aquatic survival skills may be compromised in cold water thereby increasing the likelihood of drowning. This study compared physiological, psychological, and behavioral responses of humans treading water and swimming in cold and temperate water. Thirty‐eight participants were classified as inexperienced (n = 9), recreational (n = 15), or skilled (n = 10) swimmers. They performed 3 tasks: treading water (120 seconds), swim at “comfortable” pace, and swim at “fast” pace in 2 water conditions (28°C vs 10°C). Heart rate, oxygen uptake, psychometric variables, spatio‐temporal (swim speed, stroke rate, and stroke length), and coordination type were examined as a function of expertise. Tasks performed in cold water‐generated higher cardiorespiratory responses (HR = 145 ± 16 vs 127 ± 21 bpm) and were perceived about 2 points more strenuous on the Borg scale on average (RPE = 14.9 ± 2.8 vs 13.0 ± 2.0). The voluntary durations of both treading water (60 ± 32 vs 91 ± 33 seconds) and swimming at a comfortable pace (66 ± 22 vs 103 ± 34 seconds) were significantly reduced in cold water. However, no systematic changes in movement pattern type could be determined in either the treading water task or the swimming tasks. Water temperature influences the physical demands of these aquatic skills but not necessarily the behavior. Training treading water and swimming skills in temperate water seems to transfer to cold water, but we recommend training these skills in a range of water conditions to help adapt to the initial “cold‐shock” response. [ABSTRACT FROM AUTHOR]

Vegetative cultures of Clostridium botulinum produce the extremely potent botulinum neurotoxin, and may jeopardize the safety of foods unless sufficient measures to prevent growth are applied. Minimal food processing relies on combinations of mild treatments, primarily to avoid deterioration of the sensory qualities of the food. Tolerance of C. botulinum to minimal food processing is well characterized. However, data on effects of successive treatments on robustness towards further processing is lacking. Developments in genetic manipulation tools and the availability of annotated genomes have allowed identification of genetic mechanisms involved in stress tolerance of C. botulinum . Most studies focused on low temperature, and the importance of various regulatory mechanisms in cold tolerance of C. botulinum has been demonstrated. Furthermore, novel roles in cold tolerance were shown for metabolic pathways under the control of these regulators. A role for secondary oxidative stress in tolerance to extreme temperatures has been proposed. Additionally, genetic mechanisms related to tolerance to heat, low pH, and high salinity have been characterized. Data on genetic stress-related mechanisms of psychrotrophic Group II C. botulinum strains are scarce; these mechanisms are of interest for food safety research and should thus be investigated. This minireview encompasses the importance of C. botulinum as a food safety hazard and its central physiological characteristics related to food-processing and storage-related stress. Special attention is given to recent findings considering genetic mechanisms C. botulinum utilizes in detecting and countering these adverse conditions. [ABSTRACT FROM AUTHOR]

ABSTRACT DEAD-box helicases catalyze the ATP-dependent destabilization of RNA duplexes. Hera is a DEAD-box helicase from Thermus thermophilus that consists of a helicase core, followed by a C-terminal extension comprising a dimerization domain and an RNA-binding domain. The combined structural information on individual Hera domains provides a molecular model of the Hera dimer. The modular architecture with flexible connections between individual domains affords different relative orientations of the RBD relative to the Hera helicase core, and of the two helicase cores within the dimer. Presumably, domain movements are intimately linked to RNA binding, to the interplay of the RBD and the helicase core, and to RNA unwinding, and may impact on the functional cooperation of the two helicase cores in RNA unwinding. The in vivo function of Hera is unknown. The Hera RBD recognizes two distinct elements in the RNA substrate, a single-stranded and a structured region. The helicase core then unwinds an adjacent RNA duplex in an ATP-dependent reaction. Overall, this mode of action is reminiscent of DEAD-box proteins that act as general RNA chaperones. This review summarizes the current knowledge on Hera structure and function, and discusses a possible role of Hera in the Thermus thermophilus cold-shock response. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 1137-1146, 2013. [ABSTRACT FROM AUTHOR]

Abstract: Clostridium botulinum is a notorious foodborne pathogen. Its ability to adapt to and grow at low temperatures is of interest for food safety. Two-component systems (TCSs) have been reported to be involved in cold-shock and growth at low temperatures. Here we show the importance of TCS CBO2306/CBO2307 in the cold-shock response of C. botulinum ATCC 3502. The relative expression levels of the cbo2306 and cbo2307 were up to 4.4-fold induced in the cold-shocked cultures but negatively regulated in the late-log and stationary growth phase in relation to early logarithmic growth phase in non-shocked cultures. Importance of the CBO2306/CBO2307 in the cold stress was further demonstrated by impaired growth of insertional cbo2306 or cbo2307 knockout mutants in relation to the wild-type strain ATCC 3502. The results suggest that the TCS CBO2306/CBO2307 is important for cold-shock response and adaptation of C. botulinum ATCC 3502 to low temperature. [Copyright &y& Elsevier]