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PubMed1998

[Influence of stress and stress-protecting factors on rat tolerance to cold and efficiency of rat adaptation to cold].

The adaptive characteristics of the body, including the specific features of increased cold resistance upon repeated exposures to cold, are determined not only by the properties of thermogenic structures themselves, but largely depend on the contribution of the central mechanisms which control the processes of habituation and mobilization of functions. The experiments revealed an increase in cold resistance in rats after preexposure to cold. Immobilization stress prior to training cold significantly decreased rapid cold resistance in the animals, but increased the training effect of the first cooling. On the contrary, chlordiazepoxide increased cold resistance during the first cooling. Testing of the untreated animal showed no effect of training. No adaptive changes in cold resistance occurred in rats with impaired amygdaloid complex. Analyzing adrenal catecholamines revealed a significant elevation of dopamine concentrations in the rats exposed to cold. Hypothalamic catecholamines did not change with cold and serotonin in intact rats and 5-hydroxyindoleacetic acid in amygdalectomized rats substantially increased.

Adaptation, Physiological↗
PubMed2001

High-resolution two-dimensional electrophoresis separation of proteins from metal-stressed rice (Oryza sativa L.) leaves: drastic reductions/fragmentation of ribulose-1,5-bisphosphate carboxylase/oxygenase and induction of stress-related proteins.

Employing high-resolution two-dimensional electrophoresis (2-DE), we studied changes in the rice leaf protein patterns, in response to applied heavy and alkaline metals, important environmental pollutants in our surroundings. Drastic changes in 2-DE protein patterns after treatment with copper, cadmium, and mercury, over control were found, including changes in the morphology of the leaf segments. Changes in the major leaf photosynthetic protein, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO, both suppression and fragmentation), and induction of proteins are reported. A total of 33 proteins, which were highly reproducible in repeated experiments, were visually identified as changed over the control, and taken for N-terminal or internal amino acid sequencing. Among these, nine proteins were N-terminally blocked, and six proteins could not be sequenced. Most of the proteins showed homology to RuBisCO protein, and some to defense/stress-related proteins, like the pathogenesis related class 5 protein (OsPR5), the probenazole-inducible protein (referred to as the OsPR10), superoxide dismutase, and the oxygen evolving protein. Results presented here strongly indicate a highly specific action of some of these metals in disturbing the photosynthetic machinery, as evidenced by prominent reductions/fragmentation of the major photosynthetic protein, RuBisCO, and resulting in stress.

Electrophoresis, Gel, Two-Dimensional↗
PubMed2006

Quiescent gemmules of the freshwater sponge, Spongilla lacustris (Linnaeus, 1759), contain remarkably high levels of Hsp70 stress protein and hsp70 stress gene mRNA.

With the onset of changing environmental conditions in autumn, the freshwater sponge Spongilla lacustris (Linnaeus, 1759) produces resistant stages (gemmules) which are in the state of quiescence. Gemmules stored at 8 degrees C remained quiescent; however, germination occurred within 24 hr after the water temperature was increased to 22.5 degrees C. Sponges hatched through the micropyle and subsequently built new spicules and a new canal system. The molecular and biochemical mechanisms which enable the gemmules to survive long periods of adverse conditions are not known. For the first time we focused on the role of the stress protein Hsp70 and the expression of hsp70 mRNA in S. lacustris during the development of gemmules in the state of quiescence into growing sponges. The partial sequence of hsp70 seems to be a true hsp gene since transcription could be clearly enhanced by temperature elevation. The results showed a large pool of cellular Hsp70 and hsp70 mRNA in gemmules during the state of quiescence. Within hours after a temperature trigger, the Hsp70 level decreased slowly and reached approximately the level of an adult sponge. Hsp70 presumably allows gemmules to stabilize their proteins and membranes during dormancy from autumn to spring when water temperatures change.

Animals↗
PubMed1995

Intracellular serine proteinase behaves as a heat-stress protein in nongrowing but as a cold-stress protein in growing populations of Bacillus megaterium.

A temperature increase from 35 degrees to 40-42 degrees C enhances the rise of cytoplasmic serine proteinase (ISP1) activity in Bacillus megaterium incubated in a sporulation medium. A temperature shift from 27 degrees C in the growth medium to 35 degrees C in the sporulation medium has the same effect. Elevated temperature stimulates the increase of ISP1 level when applied immediately after the transfer of cells from the growth to the sporulation medium (at T0) or at T3, when sporulation becomes irreversible. The cytoplasmic PMSF-resistant activity or the proteolytic activity associated with the membrane fraction is stimulated only slightly or not at all. A temperature increase to 45-47 degrees C suppresses the rise of proteolytic activities in all cell fractions. In addition to the elevation of the ISP1 activity by an upward temperature shift, the rise of this enzyme in nongrowing cells is also stimulated by osmotic stress. In growing populations, in contrast to the rise of the ISP1 activity caused by elevated temperature in nongrowing cells, this proteinase is induced by low temperatures (24-27 degrees C). The ISP1 activity roughly correlates with the enzyme protein concentration determined by immunoblotting.

Bacillus megaterium↗
PubMed1996

Candida albicans stress mannoproteins expression in superficial and systemic candidiasis. Stress mannoproteins in Candida albicans.

The presence of heat shock mannoproteins (HSMPs) reactive with sIgA was demonstrated in several C. albicans strains. The subculture of the C. albicans isolated from mucosal surfaces on Sabouraud's dextrose agar at 25 degrees C switched off the HSMP expression. A re-expression of the HSMPs was obtained in the same medium by shifting the temperature of incubation to 37 degrees C. However, expression of HSMPs in two strains isolated from deep infections was maintained during several subcultures on Sabouraud's dextrose agar at 25 degrees C. A glycoprotein of 200 kDa seemed to be the main HSMP reacting with vaginal sIgA. The data presented in this study suggest that factors other than temperature can influence the expression of C. albicans HSMPs and therefore these antigens should be referred as stress mannoproteins.

Animals↗
PubMed2004

Heat stress response in plants: a complex game with chaperones and more than twenty heat stress transcription factors.

Compared to the overall multiplicity of more than 20 plant Hsfs, detailed analyses are mainly restricted to tomato and Arabidopsis and to three important representatives of the family (Hsfs A1, A2 and B1). The three Hsfs represent examples of striking functional diversification specialized for the three phases of the heat stress (hs) response (triggering, maintenance and recovery). This is best illustrated for the tomato Hsf system: (i) HsfA1a is the master regulator responsible for hs-induced gene expression including synthesis of HsfA2 and HsfB1. It is indispensible for the development of thermotolerance. (ii) Although functionally equivalent to HsfA1a, HsfA2 is exclusively found after hs induction and represents the dominant Hsf, the "working horse" of the hs response in plants subjected to repeated cycles of hs and recovery in a hot summer period. Tomato HsfA2 is tightly integrated into a network of interacting proteins (HsfA1a, Hsp17-CII, Hsp17-CI) influencing its activity and intracellular distribution. (iii) Because of structural peculiarities, HsfB1 acts as coregulator enhancing the activity of HsfA1a and/or HsfA2. But in addition, it cooperates with yet to be identified other transcription factors in maintaining and/or restoring housekeeping gene expression.

Amino Acid Sequence↗
PubMed1999

Restoration of culturability of starvation-stressed and low-temperature-stressed Escherichia coli O157 cells by using H2O2-degrading compounds.

Late-exponential-phase cells of Escherichia coli O157:H- strain E32511/HSC became nonculturable in sterilized distilled water microcosms at 4 degrees C. Plate counts declined from 3 x 10(6) to less than 0.1 CFU/ml in about 21 days. However, when samples of microcosms at 21 days were inoculated onto an agar medium amended with catalase or nonenzyme peroxide-degrading compounds such as sodium pyruvate or alpha-ketoglutaric acid, plate counts increased to 10(4)-10(5) CFU/ml within 48 h. The proposed mode of action of the catalase or pyruvate is via the degradation of the metabolic by-product H2O2, rather than through supplementation of a required nutrient in the recovery of nonculturable cells. Our studies were based on the assumption that E32511/HSC strain responds to starvation and a low temperature by entering a nonculturable state and that the correction of oxidative stress upon the inoculation of bacteria on agar plates promotes recovery of nonculturable cells.

Catalase↗
PubMed1985

Comparison of stress digital ventriculography, stress thallium scintigraphy, and digital fluoroscopy in the diagnosis of coronary artery disease in subjects without prior myocardial infarction.

Exercise thallium scintigraphy is often used for the diagnosis of coronary artery disease (CAD). Exercise digital subtraction ventriculography and digital subtraction fluoroscopy are new diagnostic procedures with roles that have not been determined. To compare the relative accuracies of the digital techniques with thallium scintigraphy, 97 consecutive patients without myocardial infarction underwent all 3 tests on the day before their scheduled coronary angiograms. Forty-two patients had CAD (more than 50% diameter narrowing of 1 major artery). A fixed or reversible perfusion defect defined an abnormal thallium test response and a segmental wall motion abnormality at rest or with exercise defined an abnormal digital ventriculographic response. Any visualized coronary calcific deposit defined an abnormal digital fluorographic response. The sensitivities of digital fluoroscopy (86%) and digital ventriculography (79%) were significantly higher than the sensitivity of thallium (62%) (p less than 0.05). The specificity of thallium (82%) was not significantly higher than that of either digital ventriculography (72%) or fluoroscopy (67%). The diagnostic accuracies of digital fluoroscopy, digital ventriculography, and thallium were 75%, 75% and 73%, respectively. A logistic regression model showed that thallium and digital fluoroscopy were more accurate in younger patients, whereas digital ventriculography was more sensitive in hypertensive persons and in those not taking beta-blocking drugs. The choice of test depends on disease prevalence, clinical variables (such as age and hypertension) and the importance of functional information obtained from stress testing.

Age Factors↗
PubMed1979

Combined (stressed and non-stressed) antenatal fetal heart rate monitoring.

Acceleration patterns of the fetal heart rate, or a normal heart rate during spontaneous contractions, were used as a short weekly screening test to evaluate fetal well-being in 1102 high-risk pregnancies. When accelerations or contractions were absent during the initial screening, oxytocin was administered to stimulate uterine contractions. The mean duration of the antenatal monitoring was 18.5 min when the initial antenatal monitoring was normal, but 38.8 min when the initial results were uncertain. Oxytocin was administered to 38% of patients. This reduced the number of occasions where the diagnosis was uncertain from 46.6% to 12%. Patients with uncertain antenatal fetal monitoring had significantly more late decelerations during labor as well as newborns with low Apgar scores when compared to those with normal antenatal monitoring. Patients with abnormal antenatal monitoring (positive stress test) had significantly more low 5-min Apgar scores, late decelerations during labor and growth-retarded infants than the patients with normal antenatal fetal monitoring. Only 1 intrauterine death occurred within 7 days of a normal antenatal heart rate recording. No preventable fetal deaths occurred when antenatal monitoring demonstrated an acceleration pattern of the fetal heart rate.

Female↗
PubMed2001

Social stress paradigms in male mice: Variations in behavior, stress and immunology.

Male OF1 strain mice were allocated, after 2 weeks of individual housing, to cohabitating (6 or 16 days), fixed dyadic interaction pairs (6 or 16 daily encounters) or control groups (6 or 16 days). These different social stress situations were assessed for their effects on splenic contents of NE, IL-1 and IL-2 and serum levels of corticosterone. Spleen NE contents showed no significant variations, but serum corticosterone titers were generally higher in interacting pairs and subordinates. Splenic IL-2 did not respond in the same way to the treatments as IL-1. The differences in splenic interleukin contents could not be simply related to observed changes in serum corticosterone levels. Different mechanisms appear to regulate changes in glucocorticoids and the measured cytokines. These physiological phenomena do not simply reflect in the animal's social status (dominant or submissive). The intensity and duration of the agonistic behavior displayed as well as the interaction experience accumulated may account for the observed differences between the paradigms.

Agonistic Behavior↗
PubMed2000

Plant stress-related uncoupling protein CSP 310 caused lipid peroxidation in winter wheat mitochondria under chilling stress.

The effect of CSP 310 on lipid peroxidation in winter wheat mitochondria was studied by the measurement of primary lipid peroxidation products - dienic conjugates. It was found that some concentrations of CSP 310 caused lipid peroxidation in isolated winter wheat mitochondria in all systems investigated at different concentrations during chilling stress.

Journal Article↗
PubMed1982

Nonspecific stabilization of stress-susceptible proteins by stress-resistant proteins: a model for the biological role of heat shock proteins.

It is demonstrated experimentally that addition of proteins that are themselves resistant to denaturation by heat or ethanol can nonspecifically stabilize other proteins that are ordinarily highly susceptible to inactivation. It is proposed that the diffusion-limited rate with which unfolded protein molecules encounter each other and become irreversibly crosslinked is reduced in the presence of substantial concentrations of an unreactive globular protein. We suggest that one of the functions of heat shock proteins, which are synthesized in large amounts after exposure of cells to increased temperature and other forms of stress, may be to stabilize other proteins kinetically in a similarly nonspecific fashion.

Alkaline Phosphatase↗
PubMed1996

Inhibition of translational initiation by activators of the glucose-regulated stress protein and heat shock protein stress response systems. Role of the interferon-inducible double-stranded RNA-activated eukaryotic initiation factor 2alpha kinase.

Depletion of endoplasmic reticulum (ER) Ca2+ perturbs protein folding and processing within the organelle while inhibiting translational initiation through activation of the double-stranded RNA-activated eukaryotic initiation factor (eIF)-2alpha kinase (PKR) (Prostko, C. R., Dholakia, J. N., Brostrom, M. A., and Brostrom, C. O. (1995) J. Biol. Chem. 270, 6211-6215). The glucose-regulated stress protein (GRP) chaperones are subsequently induced. We now report that sodium arsenite, a prototype for stressors fostering cytoplasmic protein misfolding, also inhibits translational initiation through activation of PKR while subsequently inducing the heat shock protein (HSP) chaperones. Arsenite neither mobilized ER-associated Ca2+ nor slowed peptide chain elongation. Various HSP-inducing chemicals caused rapid phosphorylation of eIF-2alpha. When incubated with double-stranded RNA, extracts derived from arsenite-treated cells displayed greater degrees of phosphorylation of PKR and eIF-2alpha than did control extracts. Cells overexpressing a dominant negative PKR mutation resisted translational inhibition and eIF-2alpha phosphorylation in response to ER or cytoplasmic stressors. Induction of either the HSP or GRP chaperones was accompanied by development of translational tolerance to either Ca2+-mobilizing agents or arsenite. Following induction of the HSPs by arsenite, cells remained susceptible to induction of the GRPs by Ca2+-mobilizing agents. Conversely, cells possessing induced GRP contents in response to Ca2+-mobilizing agents readily induced the HSPs in response to arsenite. It is concluded that the two chaperone systems function independently except for their mutual suppression of PKR.

3T3 Cells↗
PubMed2005

Aluminium resistance requires resistance to acid stress: a case study with spinach that exudes oxalate rapidly when exposed to Al stress.

Spinach is a vegetable with a high oxalate concentration in its tissues. Oxalate efflux from spinach (Spinacia oleracea L. cv. Quanneng) roots was rapidly stimulated (within 30 min) by aluminium (Al) treatment. The efflux was constant within 6 h, but increased with increasing Al concentration. The efflux was confined to the root tip (0-5 mm), which showed a 5-fold greater efflux than the root zone distal to the tip (5-10 mm). Oxalate efflux could not be triggered by treatment with the trivalent cation lanthanum or by phosphorus deficiency, indicating that the efflux was specific to the Al treatment. All this evidence suggested that spinach possesses Al-resistance mechanisms. However, spinach was found to be as sensitive to Al toxicity as the Al-sensitive wheat line ES8, which had no Al-dependent organic acids efflux. The Al accumulated in the apical 5 mm of the roots of spinach which was also similar to that in the Al-sensitive wheat after 24 h treatment with 50 microM AlCl(3), indicating a non-exclusion mechanism. In addition, root elongation in spinach was significantly inhibited at pH 4.5, compared with that at pH 6.5. Based on this evidence, it is concluded that the sensitivity to acid stress in spinach could mask the potential role for oxalate to protect the plant roots from Al toxicity.

Aluminum Chloride↗
PubMed1988

Water stress integral-a link between short-term stress and long-term growth.

Water stress integral (S(Psi)), the cumulative integral of pre-dawn leaf water potential over any chosen period of time, was estimated from measurements of pre-dawn water potential made every two weeks in a Pinus radiata D. Don plantation near Canberra, Australia. Also measured were final length of current-season needles and annual stem basal area increment. Data were gathered over a 4-year period from a control plot, a fertilized plot, an irrigated plot, and two plots that were both fertilized and irrigated. Among years and treatments, annual basal area increment varied over a threefold range. Of this variation, 91% was accounted for by variation in S(Psi) for the entire year, during every month of which stem diameter growth occurred. Of variation in annual needle elongation, 90% was accounted for by variation in S(Psi) from late August to late February, which was the period of needle growth. In dry years, the annual value of S(Psi) in non-irrigated plots was mainly determined by soil water content, but in wet years in non-irrigated plots, and in all years in irrigated plots, it was closely correlated with tree nutrient status (r(2) = 0.81).

Journal Article↗
PubMedDate not supplied

The effects of mindfulness-based stress reduction on nurse stress and burnout, Part II: A quantitative and qualitative study.

This article is the second in a series reporting on research exploring the effects of Mindfulness-based Stress Reduction on nurses and describes the quantitative data. The third article describes qualitative data. Treatment group participants reduced scores on 2 of 3 subscales of the Maslach Burnout Inventory significantly more than wait-list controls; within-group comparisons for both groups pretreatment and posttreatment revealed similar findings. Changes were maintained as long as 3-month posttreatment. Implications of these findings are discussed.

Adult↗
PubMedDate not supplied

The effects of mindfulness-based stress reduction on nurse stress and burnout: a qualitative and quantitative study, part III.

Part III of the study on mindfulness-based stress reduction (MBSR) describes qualitative data and discusses the implications of the findings. Study analysis revealed that nurses found MBSR helpful. Greater relaxation and self-care and improvement in work and family relationships were among reported benefits. Challenges included restlessness, physical pain, and dealing with difficult emotions.

Adult↗
PubMed2006

Osmotic stress in Synechocystis sp. PCC 6803: low tolerance towards nonionic osmotic stress results from lacking activation of glucosylglycerol accumulation.

In order to compare the molecular principles of the acclimatization of bacterial cells to salt and nonionic osmotic stress, the moderately halotolerant cyanobacterium Synechocystis sp. PCC 6803 was challenged by salt (NaCl), and the osmolytes sorbitol and maltose. The physiological response towards each of the three compounds was found to be different. After salt addition, the cell volume remained unchanged, and the accumulation of the osmoprotective compound glucosylglycerol (GG) was observed after activation of the key enzyme GgpS at the biochemical and gene (ggpS) expression level. Sorbitol addition had only minor effects on the cell volume. In spite of the fact that the ggpS expression was increased, the GgpS enzyme was not activated, resulting in the absence of GG accumulation. In contrast the cells accumulated sorbitol, which served as a compatible solute and assured a certain osmotic resistance. In comparison to NaCl and sorbitol, the addition of maltose caused a strong decrease in cell volume indicating water efflux. However, no osmolyte accumulation was observed, resulting in an osmosensitive phenotype. Consequently, a successful response of Synechocystis cells to an osmotic challenge is indicative of the de novo synthesis of GG upon salt-dependent activation of the GgpS enzyme or the uptake of external solutes.

Bacterial Proteins↗