100 resultados para Salt stress. Osmolytes. Halobacteria and metagenome

em Deakin Research Online - Australia


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Knots Calidris canutus and sanderlings C. alba were used in cage experiments in which water and food consumption were measured under different salt regimes. Food consumption decreased and water consumption increased after changing the water provided from fresh to salt. Knots have the capability of adapting to salt water. Swallowing of adherent water with the prey, as well as evaporative cooling in heat stressed birds, might increase salt stress. -from Authors

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The current study explored the relationships between physical and emotional stress and the symptomatology of chronic fatigue syndrome (CFS). Fifty-four CFS patients were studied using a longitudinal design. A self-report format was used to collect daily measures of major physical (sleep disturbance and physical activity) and emotional (subjective emotional stress level) stressors, as well as measures of levels of fatigue and secondary symptoms. The variables accounted for a moderate variance at the individual and occasion levels. Sleep disturbance and emotional stress were found to be positively associated with levels of fatigue and symptomatology, whereas physical activity was found to have a negative relationship with fatigue only. The severity of fatigue and symptoms were found to fluctuate daily in relation with the variables, indicating the complex nature of the associations.

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Stress is thought to influence human eating behavior and has been examined in animal and human studies. Our understanding of the stress-eating relation is confounded by limitations inherent in the study designs; however, we can make some tentative conclusions that support the notion that stress can influence eating patterns in humans. Stress appears to alter overall food intake in two ways, resulting in under- or overeating, which may be influenced by stressor severity. Chronic life stress seems to be associated with a greater preference for energy- and nutrient-dense foods, namely those that are high in sugar and fat. Evidence from longitudinal studies suggests that chronic life stress may be causally linked to weight gain, with a greater effect seen in men. Stress-induced eating may be one factor contributing to the development of obesity. Future studies that measure biological markers of stress will assist our understanding of the physiologic mechanism underlying the stress-eating relation and how stress might be linked to neurotransmitters and hormones that control appetite.

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High rates of posttraumatic stress disorder (PTSD) have been reported among people seeking treatment for substance use disorders (SUDs), although few studies have examined the relationship between PTSD and substance use in young drug users. This study compared levels of substance use, coping styles, and high-risk triggers for substance use among 66 young adults with SUD, with or without comorbid PTSD. Young people with current SUD–PTSD (n = 36) reported significantly higher levels of substance use in negative situations, as well as emotion-focused coping, compared to the current SUD-only group (n = 30). Severity of PTSD was a significant predictor of negative situational drug use, and emotion-focused coping was found to mediate this relationship. The findings underscore the need for youth substance abuse treatment programs to include coping skills training and management of affect regulation for those individuals with comorbid SUD–PTSD.

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We model the optimal allocation of limited resources of an animal during a transient stressful event such as a cold spell or the presence of a predator. The animal allocates resources between the competing demands of combating the stressor and bodily maintenance. Increased allocation to combating the stressor decreases the mortality rate from the stressor, but if too few resources are allocated to maintenance, damage builds up. A second source of mortality is associated with high levels of damage. Thus, the animal faces a trade-off between the immediate risk of mortality from the stressor and the risk of delayed mortality due to the build up of damage. We analyze how the optimal allocation of the animal depends on the mean and predictability of the length of the stressful period, the level of danger of the stressor for a given level of allocation, and the mortality consequences of damage. We also analyze the resultant levels of mortality from the stressor, from damage during the stressful event, and from damage during recovery after the stressful event ceases. Our results highlight circumstances in which most mortality occurs after the removal of the stressor. The results also highlight the importance of the predictability of the duration of the stressor and the potential importance of small detrimental drops in condition. Surprisingly, making the consequences of damage accumulation less dangerous can lead to a reallocation that allows damage to build up by so much that the level of mortality caused by damage build up is increased. Similarly, because of the dependence of allocation on the dangerousness of the stressor, making the stressor more dangerous for a given level of allocation can decrease the proportion of mortality that it causes, while the proportion of mortality caused by damage to condition increases. These results are discussed in relation to biological phenomena.

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Bird song is a sexually selected trait and females have been shown to prefer males that sing more complex songs. However, for repertoire size to be an honest signal of male quality it must be associated with some form of cost. This experiment investigates the effects of food restriction and social status during development on song complexity in the European starling (Sturnus vulgaris). Birds that experienced an unpredictable food supply early in life produced a significantly smaller repertoire of song phrases than those with a constant food supply. Social status during development was also significantly correlated with repertoire size, with dominant birds producing more phrase types. This study therefore provides novel evidence that social as well as nutritional history may be important in shaping the song signal in this species.

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Hospitality was found to be a potentially high stress occupation. Potential work and family stressors, symptoms, affective factors, coping strategies and resources were identified. A stress-psychological health model was developed. Possible implications for stress research, measurement, prevention and management in the hospitality industry were proposed.

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Focus groups of nurses from both in-centre and satellite dialysis units were undertaken followed by questionnaires. The In-centre nursing staff rated the busy-ness of the unit as the maximum stress. The mostly notable stressor for the staff at the satellite unit related to patient behaviour and the perceived unrealistic expectations of the patient followed by patients arriving unwell at the unit.

Nurses suffer stress on a daily basis in both in-centre and satellite dialysis units. The major stressors differ from in-centre to satellite dialysis units.

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Oxidative stress plays a central role in neuronal injury and cell death in acute and chronic pathological conditions. The cellular responses to oxidative stress embrace changes in mitochondria and other organelles, notably endoplasmic reticulum, and can lead to a number of cell death paradigms, which cover a spectrum from apoptosis to necrosis and include autophagy. In Alzheimer's disease, and other pathologies including Parkinson's disease, protein aggregation provides further cellular stresses that can initiate or feed into the pathways to cell death engendered by oxidative stress. Specific attention is paid here to mitochondrial dysfunction and programmed cell death, and the diverse modes of cell death mediated by mitochondria under oxidative stress. Novel insights into cellular responses to neuronal oxidative stress from a range of different stressors can be gained by detailed transcriptomics analyses. Such studies at the cellular level provide the key for understanding the molecular and cellular pathways whereby neurons respond to oxidative stress and undergo injury and death. These considerations underpin the development of detailed knowledge in more complex integrated systems, up to the intact human bearing the neuropathology, facilitating therapeutic advances.

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Workplace stress associated with ongoing processes of organizational change is a major occupational and public health concern. It is also a costly economic issue—both public and private. In this paper a framework will be used that draws on Michel Foucault’s genealogies of the Self to suggest that the management of stress by professionals—in a workplace environment increasingly characterized by the practices of risk management—emerges as a key element of the choices and responsibilities that frame what it means to be professional. To be (a) professional means to be a person capable of making choices and accepting responsibilities that are framed by a duty of care to manage one’s health and well-being to maximize organizational performance and effectiveness. The article will examine the ways in which transformations in the organization and practice of teachers’ work have witnessed large numbers of teachers being seen, and seeing themselves, as stressed. These understandings of teacher stress have provoked a number of strategies designed to encourage individuals to take care of themselves—and to take care of themselves in ways that will make schools more effective. The authors are concerned with understanding the processes that are at work which make it possible to imagine that it is a professional duty of care to manage one’s life in such a way as to be both balanced and effective in contexts of uncertainty and risk.

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This paper reviews new drug targets in the treatment of depression and new drug candidates to treat depression. Depression is characterized by aberrations in six intertwined pathways: (1) inflammatory pathways as indicated by increased levels of proinflammatory cytokines, e.g. interleukin-1 (IL-1), IL-6, and tumour necrosis factor α. (2) Activation of cell-mediated immune pathways as indicated by an increased production of interferon γ and neopterin. (3) Increased reactive oxygen and nitrogen species and damage by oxidative and nitrosative stress (O&NS), including lipid peroxidation, damage to DNA, proteins and mitochondria. (4) Lowered levels of key antioxidants, such as coenzyme Q10, zinc, vitamin E, glutathione, and glutathione peroxidase. (5) Damage to mitochondria and mitochondrial DNA and reduced activity of respiratory chain enzymes and adenosine triphosphate production. (6) Neuroprogression, which is the progressive process of neurodegeneration, apoptosis, and reduced neurogenesis and neuronal plasticity, phenomena that are probably caused by inflammation and O&NS. Antidepressants tend to normalize the above six pathways. Targeting these pathways has the potential to yield antidepressant effects, e.g. using cytokine antagonists, minocycline, Cox-2 inhibitors, statins, acetylsalicylic acid, ketamine, ω3 poly-unsaturated fatty acids, antioxidants, and neurotrophic factors. These six pathways offer new, pathophysiologically guided drug targets suggesting that novel therapies could be developed that target these six pathways simultaneously. Both nuclear factor (erythroid-derived 2)-like 2 (Nrf2) activators and glycogen synthase kinase-3 (GSK-3) inhibitors target the six above-mentioned pathways. GSK-3 inhibitors have antidepressant effects in animal models of depression. Nrf2 activators and GSK-3 inhibitors have the potential to be advanced to phase-2 clinical trials to examine whether they augment the efficacy of antidepressants or are useful as monotherapy.

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Objective: Depression is accompanied by activation of immuno-inflammatory and oxidative and nitrosative stress (IO&NS) pathways, and increased IgM/IgA responses to lipopolysaccharide (LPS) of gram-negative commensal bacteria. The latter suggests that bacterial translocation has caused IgM/IgA responses directed against LPS. Bacterial translocation may drive IO&NS responses.

Method: To examine the associations between IgM/IgA responses to LPS and IO&NS measurements, including plasma/serum interleukin-1 (IL-1), tumor necrosis factor (TNF)α, neopterin, lysozyme, oxidized LDL (oxLDL) antibodies, peroxides, and IgM (auto)immune responses against malondialdehyde (MDA), azelaic acid, phophatidyl inositol (Pi), NO-tryptophan and NO-tyrosine in depressed patients and controls.

Results:
We found significant positive associations between IgM/IgA responses to LPS and oxLDL antibodies, IgM responses against MDA, azelaic acid, Pi, NO-tryptophan, and NO-tyrosine. The IgA responses to LPS were correlated with lysozyme. There were no significant positive correlations between the IgM/IgA responses to LPS and IL-1 and neopterin.

Conclusion
: The findings show that in depression there is an association between increased bacterial translocation and lysozyme production, an antibacterial compound, O&NS processes, and autoimmune responses directed against O&NS generated neoantigenic determinants. It is suggested that bacterial translocation may drive IO&NS pathways in depression and thus play a role in its pathophysiology.

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The current salt intake is very high for children as well as adults in China. A reduction in salt intake is one of the most cost-effective measures to curb the rapidly growing disease burden attributed to blood pressure and cardiovascular disease in the Chinese population. A lower salt diet starting from childhood has the potential to prevent the development of such conditions. The School-EduSalt (School-based Education Programme to Reduce Salt) study aims to determine whether an education programme targeted at school children can lower salt intake in children and their families.