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ATF3 in non-Cancer Host Cells Contributes to Stress-Enhanced Cancer ProgressionChang, Yi Seok 22 September 2016 (has links)
No description available.
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ROLE OF DIETARY INTERVENTIONS IN REDUCING THE NEGATIVE IMPACT OF STRESSFUL EVENTS IN THE PIGCandace Moriah Young (13171671) 29 July 2022 (has links)
<p>Two experimentswere conducted using pigs at different life stages to determine the effects of dietary tryptophan and water delivered oregano essential oil on growth performance, rectal temperature, water use,intestinal integrity and gene expression of biomarkers in the face heat or transport stress. In the first experiment, 192 grow-finish pigs were used to investigate the effects of water supplementation of oregano essential oil (OEO) on growth performance, water intake, rectal temperature, intestinal integrity, and expression of genetic biomarkers during an acute heat challenge. Pigs were randomly allotted to 2 X 2 factorial arrangement of treatments with pigs being heat stressed or not and being supplemented with OEO or not with 8 replicate pens of each treatment with 6 pigs/pen (4 barrows, 2 gilts per pen). Water treatments were administered immediately, with dosing at 47 μL/L of OEO. One-half of the pigs on each water treatment remained under thermoneutral conditions (TN; 21.1C), while the other half was subjected to a 3 d diurnal, acute heat stress (HS) with 12 hours at 33.3 oC (7AM-7PM) and 12 hours at 26.7oC (7PM-7AM). Three days post-HS, temperatures were reduced back to TN for the rest of the study, and pigs remained on their water treatments. Rectal temperatures were collected in the morning and evening of the heat stress period on one barrow and one gilt in each pen. Jejunal tissue was collected for subsequent histological examination and determination of gene expression. All data were analyzed using the GLM procedure of SAS (ver. 9.4). Pigs subjected to heat stress had reduced ADG (P < 0.003) and G:F (P < 0.008) during the 3d heat stress compared to pigs reared under thermoneutral conditions. However, post-heatstress, heat stressed pigs had compensatory gain resulting in increased ADG (P < 0.001) and G:F (P < 0.001) compared to thermoneutral reared pigs. Overall, there was an interaction (P < 0.006) observed between water and heat treatment with OEO increasing ADG in thermoneutral pigs but not in heat stressed pigs. Similarly, interactions between water and heat treatment were observed for ADFI during heat stress (P < 0.004), post heat stress (P < 0.01), and overall (P < 0.004) from increasing OEO intake in thermoneutral pigs but not in heat stressed pigs. Rectal temperatures were higher (P < 0.001) for heat stressed pigs at the end of d 1 and 2 of the acute heat challenge compared to TN housed pigs. Pigs exposed to HS also used more water than pigs housed in a thermoneutral environment (P < 0.002). There were no differences between villi height, crypt depth or VH:CD between treatment groups (P >0.05). There was also no difference in TP53 and CDKNA1 gene expression among treatments (P > 0.10). In the second experiment, 36 barrows were used in an 18d experiment to investigate the effects of pre-weaning tryptophan supplementation on performance and intestinal integrity following weaning with or without transport stress at weaning. Pigs were randomly allotted to 2 X 2 factorial arrangement of treatments of pre-weaning tryptophan supplementation or not and weaning transport or not. Pigs on the tryptophan treatment received 0.35, 0.45, and 0.55 g Trp/d in 5 day intervals, beginning 15 d prior to weaning.Tryptophan was dissolved in chocolate milk and administered by oral gavage with control pigs receiving milk only. At weaning, 4 pigs from each pre-weaning treatmentwere euthanized for collection of jejunal tissue. Of the remaining pigs, half the pigs oneach treatment were transported for 12 h, and half were moved into individual pens with no transport. Following transport, all pigs were individually housed and provided ad libitum access towater andfeed from a common diet. On d 3 post-weaning, all pigswere euthanized for collection of jejunal tissue. Jejunal tissue was used for histological examination and for determination of gene expression. All data were analyzed using the GLM procedure of SAS (9.4). No effects of Trp supplementation were observed on pre-weaning (P > 0.10) growth. Pig BW and ADFI were unaffected (P > 0.10) by Trp supplementation and transport at weaning. Post-weaning, there was a tendency (P < 0.06) for an effect of transport on ADG as transported pigs lost weight in the 3 d post-weaning period while non-transported pigs gained slightly. Gain:Feed post-weaning was lower (P < 0.04) for transported pigs compared to non-transported pigs. No differences were observed for villus base and mid width, villus height, crypt depth or villus height:crypt depth. There was a tendency for an interaction of transportation and Trp supplementation (P < 0.06) on villi base width driven by an increased villus width in non-transported pigs given supplemental Trp but a decrease in villus width in transported pigs given supplemental Trp.These results conclude that these alleviating agents had minimal effects when pigs were stressed, however TN grow-finish pigs benefitted from OEO water supplementation among growth performance.</p>
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Distinct Mechanisms Regulate Induction of Stress Effector, gadd45bZumbrun, Steven David January 2008 (has links)
The GADD45 family of proteins consists of three small nuclear proteins, GADD45A, GADD45B, and GADD45G, which are implicated in modulating the cellular response to various types of genotoxic/physiological stress. This family of proteins has been shown to interact with and modulate the function of cell-cycle control proteins, such as p21 and cdc2/cyclin B1, the DNA repair protein, PCNA, key stress response MAP kinases, including MEKK4 (an upstream regulator of JNK kinase), and p38 kinase. Despite similarities in amino acid sequence, structure and function, each gadd45 gene is induced differentially, depending on the type of stress stimuli. For example, the alkylating agent, methylmethane sulfonate (MMS), rapidly induces all three genes, whereas hydrogen peroxide and sorbitol preferentially induce gadd45a and gadd45b, respectively. Studies of the mechanisms of the stress-mediated induction of the gadd45 genes have predominantly focused on gadd45a, with knowledge of gadd45b and gadd45g regulation lacking. Thus, in order to generate a more complete understanding of the collective regulation of the gadd45 genes, a comprehensive analysis of the stress-mediated induction of gadd45b has been carried out. Towards this end, a gadd45b promoter-reporter construct was generated, consisting of 3897bp sequence upstream of the transcription start site of gadd45b, fused to a luciferase reporter. In a human colorectal carcinoma cell line (RKO), in which gadd45b mRNA levels profoundly increase by various stress stimuli, we observe similar, high levels of induction of the gadd45b-luciferase construct with MMS or UVC treatments, but surprisingly not with sorbitol or anisomycin. Linker-scanning mutagenesis of the gadd45b promoter reveals several important MMS and UVC cis-acting responsive elements contained within the proximal promoter, including a GC-rich region and the CCAAT box. Furthermore, we have identified three constitutively bound transcription factors, Sp1, MZF1, and NFY, and one inducible factor, Egr1, which bind to these regions and which contribute to MMS-responsiveness. In contrast, a post-transcriptional mechanism appears to regulate gadd45b induction upon sorbitol treatment, as this treatment increases the gadd45b mRNA half-life, compared to MMS treatment. Interestingly, with the exception of a common cis-element, the stress-mediated induction of gadd45b appears to be mechanistically distinct from gadd45a. In conclusion, this study provides novel evidence that gadd45b induction by distinct stress agents, MMS and sorbitol, is regulated differentially at the level of mRNA transcription or mRNA stability, respectively. / Molecular Biology and Genetics
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Role of Integrated Stress Response pathway in fish cells during VHSV Ia infectionShetty, Adarsh G. 15 September 2022 (has links)
No description available.
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Minimum Ultraviolet Light Dose Determination and Characterization of Stress Responses that Affect Dose for Listeria monocytogenes Suspended in Distilled Water, Fresh Brine, and Spent BrineMcKinney, Julie 29 April 2008 (has links)
Foodborne illnesses caused by Listeria monocytogenes have long been associated with ready-to-eat (RTE) meats contaminated after the primary thermal process has been applied. It is believed that brine solutions used to chill cooked RTE products may serve as a reservoir for L. monocytogenes becoming a potential point of post-processing contamination for RTE meats. Re-circulating ultraviolet light (UV) systems are being used to inactivate L. monocytogenes in chill brines; however very little has been reported on the dose response of healthy and stressed L. monocytogenes to UV in brine solutions. The objectives of this research were to determine 1) minimum dose of UV required to inactivate L. monocytogenes in distilled water, fresh brine, undiluted spent brine, and diluted spent brine, 2) if adaptation to food processing stresses affects the dose response, and 3) if the acquisition of antibiotic resistance mechanisms provides resistance to ultraviolet light 4) effect of stress adaptation on survival in brine solutions. After UV exposure, populations were reduced as follows from greatest to least: water > fresh brine > 5% spent brine > 35% spent brine > 55% spent brine > 100% spent brine (P ≤ 0.05). There were no population differences between acid stressed and antibiotic resistant or healthy and heat shocked (P > 0.05). However, acid-stressed and sulfanilamide-resistant were more resistant to UV light than healthy and heat shocked L. monocytogenes (P ≤ 0.05). Survival in brine solutions (no UV) followed the trend, from greatest to least (P ≤ 0.05): sulfanilamide-resistant > acid-stressed > healthy > heat-shocked. Population estimates decreased from initial inoculation to final sampling for each cell type suspended in spent brine (P ≤ 0.05), but only healthy and heat- shocked cells suspended in fresh brine were significantly reduced (P ≤ 0.05). Knowledge of UV dosing required to control L. monocytogenes in brines used during RTE meat processing, and a greater understanding of the interactions that may influence dose will aid manufacturers in establishing appropriate food safety interventions for these products. / Ph. D.
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Chemical Inhibition of Nitrification: Evaluating Methods to Detect and Characterize Inhibition and the Role of Selected Stress Responses Upon Exposure to Oxidative and Hydrophobic ToxinsKelly, Richard Thomas, II 21 July 2005 (has links)
This research first examined nitrification inhibition caused by different classes of industrially relevant chemicals on activated sludge and found that conventional aerobic nitrification was inhibited by single pulse inputs of every chemical tested, with 1-chloro-2,4-dinitrobenzene (oxidant) having the most severe impact, followed by alkaline pH 11, cadmium (heavy metal), cyanide, octanol (hydrophobic) and 2,4-dinitrophenol (respiratory uncoupler). Of the different chemicals tested, the oxidative and hydrophobic chemicals showed severe nitrification inhibition relative to other treatment processes and therefore deserved further investigation. For oxidative chemicals, we hypothesized that the more severe inhibition was because nitrifying bacteria lack one or more of the microbial stress response mechanisms used to mediate the toxic effect of oxidative chemicals. During these experiments, we showed that a rapid (minutes) antioxidant potassium efflux mechanism does not exist in two nitrifying bacteria, Nitrosomonas europaea and Nitrospira moscoviensis. Furthermore, we showed that another important antioxidant molecule, glutathione, was not oxidized as readily as in a non-nitrifying bacterium. Furthermore, we hypothesized that hydrophobic chemical-induced nitrification inhibition recovered more quickly because of the presence of membrane modification stress response mechanisms. While testing this hypothesis, we showed that N. europaea modified its cell membrane in response to hydrophobic chemicals using a long-term (hours) membrane modification mechanism that required the synthesis of new fatty acids, but it did not contain a short-term (minutes) response mechanism involving a cis/trans isomerase. Therefore, investigating these nitrifier stress responses showed that nitrifiers lack short-term stress responses that may be used to rapidly detect inhibition, indicating that conventional methods of detecting nitrification inhibition, like differential respirometry and nitrate generation rate (NGR), are still the fastest and easiest methods to use. Because several conventional methods exist, we also investigated differences between differential respirometry and a UV method we developed to measure NGR. During these tests, we showed that the UV NGR method provided a more reliable measure of nitrification inhibition than differential respirometry, and that the time to maximum nitrification inhibition depended on the properties of the chemical toxin, which implies that longer exposure times may be needed to accurately predict nitrification inhibition. / Ph. D.
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Characterization of the Arabidopsis glutamine dumper1 mutant reveals connections between amino acid homeostasis and plant stress responsesYu, Shi 15 April 2015 (has links)
Amino acids constitute the major organic form of transported nitrogen in plants, elements for protein synthesis, and precursors of many plant secondary metabolites, such as lignin, hormones, and flavonoids. Furthermore, amino acid metabolism lies at the crossroad of carbon and nitrogen metabolism. The Arabidopsis glutamine dumper1 (gdu1) mutant secretes glutamine from hydathodes, a phenotype caused by the overexpression of Glutamine Dumper1 (GDU1). GDU1 is a small transmembrane protein presents only in higher plants. The gdu1-1D mutant shows a pleiotropic phenotype: perturbed amino acid metabolism, tolerance to exogenous toxic concentrations of amino acids, elevated amino acid export, and activated stress/defense responses, lesions, and smaller rosettes. The biochemical function of GDU1 remains elusive. To better elucidate the biological processes leading to the complex Gdu1D phenotype, two approaches were conducted: (1) An ethyl methanesulfonate suppressor screening of the Gdu1D phenotype, which led to the isolation of intragenic mutations in GDU1 and mutations in the ubiquitin ligase LOG2 (Loss Of Gdu1D 2). Study of the intragenic mutations in GDU1 helped to characterize its structure-function relationships. Characterization of LOG2 showed that LOG2 interacts with GDU1 and is necessary for the Gdu1D phenotype. (2) The responses of the plant to the dexamethasone-induced expression of GDU1 were studied over time. This experiment identified major signaling pathways contributing to different components of the Gdu1D phenotype and the early events triggered by the perturbation of amino acid homeostasis. Our results showed that GDU1 overexpression first increases amino acid export, which is followed by amino acid imbalance and stress responses. This study sheds light on how amino acid imbalance interacts with various plant signaling pathways and stress responses, and suggests that LOG2 is involved in this process. / Ph. D.
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Investigating the impact of the stress response on C. elegans behaviour and the mechanisms by which MANF promotes organismal fitness and cellular health / Stress Response Behaviour and Mechanism of MANFTaylor, Shane January 2024 (has links)
Nothing is perfect, and this includes the ability to maintain homeostasis within the cell with age. Factors such as aging, chemicals, and gene dysfunction disrupt cellular homeostasis, leading to increased stress and compromising the ability of animals to maintain a healthy lifespan. Dysregulated homeostasis can be detrimental on an organismal level, impacting locomotion, and on a cellular level causing proteins to misfold and become aggregates, which are toxic to cells. Toxic protein aggregation and loss of locomotory function are key hallmarks of several age-related diseases. My Ph.D. work examined the collapse of homeostasis on electrotaxis, the age-associated increase in proteotoxicity, the decline in longevity, and neuronal and muscle health. On a behavioural level I demonstrated that loss of various components of the MT-UPR, ER-UPR, and HSR modulated the speed of animals. Additionally, I found that activation of stress responses due to chemicals and exercise reduced and increased the speed of animals respectively. On a cellular level I elucidated potential mechanisms by which Mesencephalic Astrocyte Derived Neurotrophic Factor (MANF) affects the stress response to maintain homeostasis and prevent protein aggregation. I observed the novel localization and role of MANF in lysosomes to potentially act as a critical regulator of the stress response to maintain proteostasis, neuronal health and longevity, thereby bringing balance to the cell. Furthermore, the broad tissue expression of MANF revealed its localization to muscles. This supports the ability of MANF to act as more than a neurotrophic factor as it was found to be required for muscular health in animals in an age-dependent manner. Overall, my Ph.D. research has provided new insights into the stress response and behaviour and the precise role of MANF in mediating stress response signaling to promote organismal and cellular fitness. / Dissertation / Doctor of Science (PhD) / Cellular perturbations or stress disrupt homeostasis, activating multiple stress responses. Activation of the stress response can determine the fate of an organism and is crucial to its health. Although the stress response pathways are generally understood, little is known about how the stress responses preserve animal behaviour or how they are regulated to promote organismal survival. My work has provided a basis for how stress responses affect behaviour positively and negatively in animals. I found that the stress response required mesencephalic astrocyte derived neurotrophic factor (MANF) to promote organismal survival. My thesis determined that MANF acts as more than a neurotrophic factor. MANF was found to not only be essential in neuronal health but also longevity and muscle health. Overall, this thesis demonstrated the impact of stress response on behaviour and the potential mechanism by which MANF is cytoprotective in whole organisms.
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Surface-Enhanced Raman Spectroscopy Enabled Microbial SensingWang, Wei 04 March 2024 (has links)
Pathogenic microbial contamination of the environment poses a significant threat to human health. Accordingly, microbial surveillance is needed to ensure safe drinking water and air quality. Current analytical methods for microbes are generally either culture-based, gene amplification-based, or sequencing-based. However, these approaches require centralized facilities, well-trained personnel, and specialized instruments that result in high costs and long turnaround times. Surface-enhanced Raman spectroscopy (SERS)-based techniques have been proposed to overcome these limitations. In this dissertation, we discuss work conducted to develop novel SERS-based methods to enable both sensitive microbial quantification and analysis of the interactions of pathogens, their hosts, and the surrounding environment. We first developed a labeled SERS-based lateral flow test for virus quantification. Optimization of the lateral flow design and digital signal analysis enabled high sensitivity towards SARS-CoV-2. To elicit a comprehensive understanding of pathogen infection, label-free living-cell SERS sensors were engineered by incubating host cells with nanoparticles. SERS spectral changes in host cellular components and metabolites during infection were used for viral quantification and offered inherent insights into the temporal and spatial molecular-level mechanisms of infection. These biosensors were validated using bacteriophage Phi6 and then developed for infectious H1N1 influenza. To understand microbial survival in the environment, living-cell SERS methods were applied under various conditions. Results showed cell inactivation and antibiotic treatment induced significant cellular and metabolic responses in the living whole-cell sensors, implying their potential applicability to various environmental conditions. Our research achieves rapid and on-site pathogen quantification and infection mechanism identification. / Doctor of Philosophy / Pathogenic microbes, such as the SARS-CoV-2 virus, can spread through air and water and are potentially harmful to human health. Monitoring the concentrations of these microbes in the environment is crucial to track their presence and provide an early warning of their spread. Unfortunately, current microbial detection methods are often expensive and take a long time since they typically require professional facilities and expert elicitation. Our research relies on a technique called surface-enhanced Raman spectroscopy (SERS) to address these challenges. SERS enables identification and quantification of microbes by analyzing specific features (i.e., peak position, peak intensity) in the spectra. We first applied this technique by modifying a commercial SARS-CoV-2 antigen test kit with a label molecule that provides SERS signals. We achieve accurate and sensitive quantification, even in the presence of high levels of environmental interference. To better understand how these harmful microbes interact with our bodies, we developed sensors that can measure SERS signal changes in host cells before and after infection. These sensors were tested using the bacteriophage virus Phi6 that infects bacteria and infectious H1N1 influenza virus. Furthermore, we applied these sensors to study how bacteria respond to different environmental conditions, providing valuable insights into their survival and behavior under various conditions. In summary, our research introduces methods that are more accessible to identify and quantify harmful microbes that can be potentially used by the general public. The methods provide us with molecular level understanding of pathogen interactions with humans and the environment.
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A model for homeopathic remedy effects: low dose nanoparticles, allostatic cross-adaptation, and time-dependent sensitization in a complex adaptive systemBell, Iris, Koithan, Mary January 2012 (has links)
BACKGROUND:This paper proposes a novel model for homeopathic remedy action on living systems. Research indicates that homeopathic remedies (a) contain measurable source and silica nanoparticles heterogeneously dispersed in colloidal solution / (b) act by modulating biological function of the allostatic stress response network (c) evoke biphasic actions on living systems via organism-dependent adaptive and endogenously amplified effects / (d) improve systemic resilience.DISCUSSION:The proposed active components of homeopathic remedies are nanoparticles of source substance in water-based colloidal solution, not bulk-form drugs. Nanoparticles have unique biological and physico-chemical properties, including increased catalytic reactivity, protein and DNA adsorption, bioavailability, dose-sparing, electromagnetic, and quantum effects different from bulk-form materials. Trituration and/or liquid succussions during classical remedy preparation create "top-down" nanostructures. Plants can biosynthesize remedy-templated silica nanostructures. Nanoparticles stimulate hormesis, a beneficial low-dose adaptive response. Homeopathic remedies prescribed in low doses spaced intermittently over time act as biological signals that stimulate the organism's allostatic biological stress response network, evoking nonlinear modulatory, self-organizing change. Potential mechanisms include time-dependent sensitization (TDS), a type of adaptive plasticity/metaplasticity involving progressive amplification of host responses, which reverse direction and oscillate at physiological limits. To mobilize hormesis and TDS, the remedy must be appraised as a salient, but low level, novel threat, stressor, or homeostatic disruption for the whole organism. Silica nanoparticles adsorb remedy source and amplify effects. Properly-timed remedy dosing elicits disease-primed compensatory reversal in direction of maladaptive dynamics of the allostatic network, thus promoting resilience and recovery from disease.SUMMARY:Homeopathic remedies are proposed as source nanoparticles that mobilize hormesis and time-dependent sensitization via non-pharmacological effects on specific biological adaptive and amplification mechanisms. The nanoparticle nature of remedies would distinguish them from conventional bulk drugs in structure, morphology, and functional properties. Outcomes would depend upon the ability of the organism to respond to the remedy as a novel stressor or heterotypic biological threat, initiating reversals of cumulative, cross-adapted biological maladaptations underlying disease in the allostatic stress response network. Systemic resilience would improve. This model provides a foundation for theory-driven research on the role of nanomaterials in living systems, mechanisms of homeopathic remedy actions and translational uses in nanomedicine.
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