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PubMed2000

A stress-inducible gene for 9-cis-epoxycarotenoid dioxygenase involved in abscisic acid biosynthesis under water stress in drought-tolerant cowpea.

Four cDNA clones named CPRD (cowpea responsive to dehydration) corresponding to genes that are responsive to dehydration were isolated using differential screening of a cDNA library prepared from 10-h dehydrated drought-tolerant cowpea (Vigna unguiculata) plants. One of the cDNA clones has a homology to 9-cis-epoxycarotenoid dioxygenase (named VuNCED1), which is supposed to be involved in abscisic acid (ABA) biosynthesis. The GST (glutathione S-transferase)-fused protein indicates a 9-cis-epoxycarotenoid dioxygenase activity, which catalyzes the cleavage of 9-cis-epoxycarotenoid. The N-terminal region of the VuNCED1 protein directed the fused sGFP (synthetic green-fluorescent protein) into the plastids of the protoplasts, indicating that the N-terminal sequence acts as a transit peptide. Both the accumulation of ABA and expression of VuNCED1 were strongly induced by drought stress in the 8-d-old cowpea plant, whereas drought stress did not trigger the expression of VuABA1 (accession no. AB030295) gene that encodes zeaxanthin epoxidase. These results indicate that the VuNCED1 cDNA encodes a 9-cis-epoxycarotenoid dioxygenase and that its product has a key role in the synthesis of ABA under drought stress.

Abscisic Acid↗
PubMed1983

Stress tolerance and stress-induced injury in crop plants measured by chlorophyll fluorescence in vivo: chilling, freezing, ice cover, heat, and high light.

The proposition is examined that measurements of chlorophyll fluorescence in vivo can be used to monitor cellular injury caused by environmental stresses rapidly and nondestructively and to determine the relative stress tolerances of different species. Stress responses of leaf tissue were measured by F(R), the maximal rate of the induced rise in chlorophyll fluorescence. The time taken for F(R) to decrease by 50% in leaves at 0 degrees C was used as a measure of chilling tolerance. This value was 4.3 hours for chilling-sensitive cucumber. In contrast, F(R) decreased very slowly in cucumber leaves at 10 degrees C or in chilling-tolerant cabbage leaves at 0 degrees C. Long-term changes in F(R) of barley, wheat, and rye leaves kept at 0 degrees C were different in frost-hardened and unhardened material and in the latter appeared to be correlated to plant frost tolerance. To simulate damage caused by a thick ice cover, wheat leaves were placed at 0 degrees C under N(2). Kharkov wheat, a variety tolerant of ice encapsulation, showed a slower decrease in F(R) than Gatcher, a spring wheat. Relative heat tolerance was also indicated by the decrease in F(R) in heated leaves while changes in vivo resulting from photoinhibition, ultraviolet radiation, and photobleaching can also be measured.

Journal Article↗
PubMed1986

Photosynthetic responses of leaves to water stress, expressed by photoacoustics and related methods : I. Probing the photoacoustic method as an indicator for water stress in vivo.

The effect of leaf desiccation on the photosynthetic activities in vivo was probed by the photoacoustic method. The aim of this research was: (a) To study the photoacoustic signal per se in varied conditions in order to develop this tool as a probe for stress conditions in vivo. (b) To obtain results pertaining to electron transport activities in vivo, and confirm conclusions based on work with isolated chloroplasts, which could otherwise be the result of nonspecific damage occurring during their isolation. Leaf discs from tobacco (Nicotiana tabacum L.) were routinely used, with other species tested also for comparison. Rapid leaf desiccation caused changes in the low frequency photoacoustic signal, attributed both to the mechanism of signal transduction, influenced by changes in the structural parameters of the leaf, and to the direct (nonstomatal) inhibition of gross photosynthesis. The dependence of the photothermal part of the signal on the frequency indicated the presence of two photothermal components, one of which persisted only at low modulation frequencies (below about 100 Hz) and which largely increased with the desiccation treatment. This component was ascribed to a thermal wave which reaches the leaf surface. The other nonvariable photothermal component was ascribed to a thermal wave propagating from the chloroplasts to the surface of the mesophyll cell. Only this component is considered in the ratio of the O(2) signal to the photothermal signal, which is used to estimate the quantum yield of photosynthesis. The specific dependence of the latter ratio on the frequency yielded a comparative quantum yield parameter from its extrapolation to zero frequency, and also indicated stress induced changes in the diffusion of O(2) through the mesophyll cell, reflected by changes in its characteristic slope. The (zero frequency extrapolated) quantum yield was markedly reduced with the progression of the water stress, indicating the inhibition of (gross) phototosynthetic electron transport in vivo. This result was expressed even more emphatically by the stronger inhibition of the photochemical energy storage, obtained by photoacoustic measurements at a high modulation frequency.

Journal Article↗
PubMed2004

Isolation and functional analysis of Arabidopsis stress-inducible NAC transcription factors that bind to a drought-responsive cis-element in the early responsive to dehydration stress 1 promoter.

The MYC-like sequence CATGTG plays an important role in the dehydration-inducible expression of the Arabidopsis thaliana EARLY RESPONSIVE TO DEHYDRATION STRESS 1 (ERD1) gene, which encodes a ClpA (ATP binding subunit of the caseinolytic ATP-dependent protease) homologous protein. Using the yeast one-hybrid system, we isolated three cDNA clones encoding proteins that bind to the 63-bp promoter region of erd1, which contains the CATGTG motif. These three cDNA clones encode proteins named ANAC019, ANAC055, and ANAC072, which belong to the NAC transcription factor family. The NAC proteins bound specifically to the CATGTG motif both in vitro and in vivo and activated the transcription of a beta-glucuronidase (GUS) reporter gene driven by the 63-bp region containing the CATGTG motif in Arabidopsis T87 protoplasts. The expression of ANAC019, ANAC055, and ANAC072 was induced by drought, high salinity, and abscisic acid. A histochemical assay using P(NAC)-GUS fusion constructs showed that expression of the GUS reporter gene was localized mainly to the leaves of transgenic Arabidopsis plants. Using the yeast one-hybrid system, we determined the complete NAC recognition sequence, containing CATGT and harboring CACG as the core DNA binding site. Microarray analysis of transgenic plants overexpressing either ANAC019, ANAC055, or ANAC072 revealed that several stress-inducible genes were upregulated in the transgenic plants, and the plants showed significantly increased drought tolerance. However, erd1 was not upregulated in the transgenic plants. Other interacting factors may be necessary for the induction of erd1 in Arabidopsis under stress conditions.

Abscisic Acid↗
PubMed2006

STABILIZED1, a stress-upregulated nuclear protein, is required for pre-mRNA splicing, mRNA turnover, and stress tolerance in Arabidopsis.

In plants, many gene transcripts are very unstable, which is important for the tight control of their temporal and spatial expression patterns. To identify cellular factors controlling the stability of unstable mRNAs in plants, we used luciferase imaging in Arabidopsis thaliana to isolate a recessive mutant, stabilized1-1 (sta1-1), with enhanced stability of the normally unstable luciferase transcript. The sta1-1 mutation also causes the stabilization of some endogenous gene transcripts and has a range of developmental and stress response phenotypes. STA1 encodes a nuclear protein similar to the human U5 small ribonucleoprotein-associated 102-kD protein and to the yeast pre-mRNA splicing factors Prp1p and Prp6p. STA1 expression is upregulated by cold stress, and the sta1-1 mutant is defective in the splicing of the cold-induced COR15A gene. Our results show that STA1 is a pre-mRNA splicing factor required not only for splicing but also for the turnover of unstable transcripts and that it has an important role in plant responses to abiotic stresses.

Arabidopsis↗
PubMed1996

Salt stress-induced proline transporters and salt stress-repressed broad specificity amino acid permeases identified by suppression of a yeast amino acid permease-targeting mutant.

A yeast mutant lacking SHR3, a protein specifically required for correct targeting of plasma membrane amino acid permeases, was used to study the targeting of plant transporters and as a tool to isolate new SHR3-independent amino acid transporters. For this purpose, an shr3 mutant was transformed with an Arabidopsis cDNA library. Thirty-four clones were capable of growth under selective conditions, but none showed homology with SHR3. However, genes encoding eight different amino acid transporters belonging to three different transporter families were isolated. Five of these are members of the general amino acid permease (AAP) gene family, one is a member of the NTR family, encoding an oligopeptide transporter, and two belong to a new class of transporter genes. A functional analysis of the latter two genes revealed that they encode specific proline transporters (ProT) that are distantly related to the AAP gene family. ProT1 was found to be expressed in all organs, but highest levels were found in roots, stems, and flowers. Expression in flowers was highest in the floral stalk phloem that enters the carpels and was downregulated after fertilization, indicating a specific role in supplying the ovules with proline. ProT2 transcripts were found ubiquitously throughout the plant, but expression was strongly induced under water or salt stress, implying that ProT2 plays an important role in nitrogen distribution during water stress, unlike members of the AAP gene family whose expression was repressed under the same conditions. These results corroborate the general finding that under water stress, amino acid export is impaired whereas proline export is increased.

Amino Acid Sequence↗
PubMed1995

Gender differences in risk perception: effects differ in stressed vs. non-stressed environments.

Contrary to previous reports that women are more concerned about environmental risks than men, we hypothesized that men and women residing in neighborhoods stressed by multiple hazards would demonstrate similar concerns about local environmental conditions. Analysis of a national data base and an aggregate of ten local data bases found greater female than male concern about local technological, behavioral, and land use hazards in good neighborhoods, but, as expected, not in stressed ones. We urge analysts to conduct more studies in stressed neighborhoods in order to better understand the perspective of those who live with environmental risks.

Adult↗
PubMed1990

Stress, depression, and mania: relationship between perceived role of stressful events and clinical and biochemical characteristics.

We investigated the perceived role of stressful events in episodes of major affective disorder in patients studied in the NIMH Clinical Research Branch Collaborative Program on the Psychobiology of Depression (Biological Studies). Using items from the Schedule for Affective Disorders and Schizophrenia (SADS), episodes were divided into environment-sensitive (high perceived role of stressful events) and autonomous (minimal or no perceived role of stressful events). Patients with environment-sensitive episodes had fewer previous episodes and a longer index episode. The groups did not differ with respect to age, gender, education, socioeconomic group, diagnosis, severity of illness, or eventual response to treatment. Unipolar depressed patients with environment-sensitive episodes had lower CSF 5-HIAA than those with autonomous episodes. Among bipolar depressed patients, those with autonomous episodes had elevated excretion of O-methylated catecholamine metabolites and of epinephrine, while those with environment-sensitive episodes had normal excretion of catecholamines and metabolites. Manic subjects with environment-sensitive episodes had elevated norepinephrine excretion, while this was normal in manics with autonomous episodes. Relationships between environmental sensitivity of affective episodes and neurotransmitter function therefore appear to be related to the type of episode.

Adaptation, Psychological↗
PubMed2006

Stress-specific role of fission yeast Gcn5 histone acetyltransferase in programming a subset of stress response genes.

Gcn5 is a coactivator protein that contributes to gene activation by acetylating specific lysine residues within the N termini of histone proteins. Gcn5 has been intensively studied in the budding yeast, Saccharomyces cerevisiae, but the features of genes that determine whether they require Gcn5 during activation have not been conclusively clarified. To allow comparison with S. cerevisiae, we have studied the genome-wide role of Gcn5 in the distantly related fission yeast, Schizosaccharomyces pombe. We show that Gcn5 is specifically required for adaptation to KCl- and CaCl(2)-mediated stress in S. pombe. We have characterized the genome-wide gene expression responses to KCl stress and show that Gcn5 is involved in the regulation of a subset of stress response genes. Gcn5 is most clearly associated with KCl-induced genes, but there is no correlation between Gcn5 dependence and the extent of their induction. Instead, Gcn5-dependent KCl-induced genes are specifically enriched in four different DNA motifs. The Gcn5-dependent KCl-induced genes are also associated with biological process gene ontology terms such as carbohydrate metabolism, glycolysis, and nicotinamide metabolism that together constitute a subset of the ontology parameters associated with KCl-induced genes.

Acetyltransferases↗
PubMed2004

PP2A phosphatase activity is required for stress and Tor kinase regulation of yeast stress response factor Msn2p.

In response to stress and nutrient starvation, the Saccharomyces cerevisiae transcription factor Msn2p accumulates in the nucleus and activates expression of a broad array of genes. Here, we analyze the role of the Tor (target of rapamycin) signaling pathway in mediating these responses. Inactivation of the Tor pathway component Tap42p using tap42(Ts) alleles causes a sustained nuclear localization similar to that after the addition of the Tor kinase inhibitor rapamycin. Effects of Tap42p inactivation and rapamycin addition could be suppressed by deletion of TIP41, which encodes a Tap42p-interacting protein. These results support the notion that rapamycin affects Msn2p by inactivating Tap42p function. Tap42p interacts with the catalytic subunit of PP2A (protein phosphatase 2A) and PP2A-like phosphatases. Deletion of either the catalytic or regulatory subunit that forms the PP2A phosphatase complex prevents nuclear accumulation of Msn2p in the tap42(Ts) strain and in wild-type strains treated with rapamycin. These results suggest that Tap42p is an inhibitor of PP2A phosphatase, which in turn inhibits nuclear export of Msn2p. Interestingly, PP2A function is also required for nuclear accumulation of Msn2p in response to stresses, such as heat and osmotic shock, as well as nitrogen (but not glucose) starvation. Thus, PP2A and the Tor kinase pathway transduce stress and nitrogen starvation signals to Msn2p. Finally, Msn2p localization is unaffected by conditional loss of 14-3-3 protein function, ruling out the possibility that 14-3-3 proteins act as a scaffold to sequester Msn2p in the cytoplasm.

14-3-3 Proteins↗
PubMed1997

Effects of dobutamine stress on myocardial blood flow, 99mTc sestamibi uptake, and systolic wall thickening in the presence of coronary artery stenoses: implications for dobutamine stress testing.

BACKGROUND: Although dobutamine stress is used with both 99mTc sestamibi (sestamibi) myocardial perfusion imaging and echocardiography for detecting coronary artery stenoses, the impact of stenosis severity on test end points (myocardial sestamibi uptake and systolic thickening, respectively) has not been clearly defined. METHODS AND RESULTS: In 15 open-chest dogs, dobutamine (2.5 to 30 microg x kg(-1) x min(-1)) was infused after placement of an LAD stenosis that reduced (n=8) or abolished (n=7) flow reserve. In dogs with reduced flow reserve, the stenotic-to-normal sestamibi activity ratio (0.86+/-0.03) significantly underestimated the approximately 2-to-1 dobutamine-induced flow disparity at the time of sestamibi injection (flow ratio, 0.53+/-0.04; P<.001). Stenotic-zone thickening increased at low but not at higher doses of dobutamine (2.9+/-0.4 versus 4.2+/-0.4 mm in normal zone at peak dobutamine; P=.055) but did not fall below baseline (2.7+/-0.3 mm). Similarly, in dogs with absent flow reserve, the sestamibi activity ratio (0.78+/-0.02) underestimated the approximately 2.5-to-1 dobutamine-induced flow disparity (flow ratio, 0.41+/-0.05; P<.001), and failure to increase systolic thickening was observed in the stenotic zone (2.7+/-0.4 versus 4.6+/-0.3 mm in the normal zone at peak stress, P<.01). In both groups of dogs, myocardial sestamibi uptake and image defect magnitudes were less than expected for the dobutamine-induced hyperemia, suggesting that dobutamine adversely affects myocardial sestamibi binding. Finally, a significant reduction in stenotic-zone thickening was seen during postdobutamine recovery, consistent with myocardial stunning. CONCLUSIONS: In the presence of stenoses that reduced or abolished regional flow reserve, (1) myocardial sestamibi uptake significantly underestimated the dobutamine-induced flow heterogeneity, (2) a "failure to increase systolic thickening" rather than a reduction in thickening was observed during dobutamine stress, and (3) myocardial stunning was observed during postdobutamine recovery.

Analysis of Variance↗
PubMedDate not supplied

[The stress index: proposed method for risk assessment of stress and burnout in health care settings].

To assess the risk from exposure to stress and burnout in health care workers, a pilot study was planned to compare and integrate the information based on the risk evaluation obtained through different parameters that can be quantified and elaborated to produce a numerical index, called the "Stress Index", and the subjective symptoms from the individual workers. For these purposes, three internationally validated questionnaires were administered: the Job Content Questionnaire, the State-Trait Anxiety Inventory and the Maslach Burnout Inventory. The study considered six different Units from three divisions of Internal Medicine of a large public hospital in Northern Italy, and a total group of 228 health care workers employed in the six units. The results showed an association between the Stress Index scores and the scores from the questionnaires. In particular, in the two units with the highest levels of the index, a significantly higher unbalance between job demand and decision latitude was observed, together with the highest levels of state and trait anxiety and of depersonalization, indicating higher burnout levels.

Burnout, Professional↗
PubMed2004

[The role of stress-kinase p38 in cell cycle blocking delay under osmotic stress].

Alteration in osmotic conditions leads to activation of some defensive mechanisms resulting in blocking the cell cycle progression. One of stress kinases, activated after osmotic stress, is p38 MAPK. In the present study the role of p38 both in intra-S-phase and G2/M checkpoint is shown. Besides, p38-dependent degradation of Cdc25A phosphatase after osmotic stress is demonstrated. Expression of stable form of Cdc25A results in a partial abrogation of G2/M block of the cell cycle, but has no effect on DNA synthesis arrest.

Cell Cycle↗
PubMed1989

Economic stress and suicide: multilevel analyses. Part 1: Aggregate time-series analyses of economic stress and suicide.

Of the research on health and economic stress, the approach that has produced the strongest findings has been the aggregate time-series analysis of unemployment and suicide rates. A review of the literature indicates that this aggregate work has been disputed on both methodological and interpretive grounds. To address these issues, two studies of the relationship between economic stress and suicide were conducted on the same population. The first, reported in this paper (Part 1), replicated the aggregate time-series work with improvements in method, using monthly data for 1975-1982 for Los Angeles. A second study (reported in Part 2) combined aggregate economic indicators with individual-level measures of stressful events, symptoms, and suicidal ideation.

Adult↗
PubMed1986

Stress fibres (SF) in human endothelial cells (HEC) under shear stress.

Human umbilical veinous endothelial cells are cultured on artificial substrates precoated with extracellular matrix from bovine corneal endothelial cells. These cultural conditions help cells to keep an elevated maintenance level for otherwise unusual time intervals. Integrity of endothelial cell layers is of special interest for nondisturbed blood circulation. Therefore we look after mechanisms of cell--cell and cell--substrate--adherence. Here we focus on stress fibres, microfilaments, which seem to play an important part in cellular adherence phenomena. Since endothelial cells in vivo are constantly shear stressed by the blood stream we investigated cell--substrate interactions in vitro under dynamical conditions with the help of a modified cone--plate rheometer originally designed for hemorheology. It can be demonstrated in these shearing experiments that toxical substances influence the organization of stress fibres.

Actin Cytoskeleton↗
PubMed1985

Periosteal stress-induced reactions resembling stress fractures. A radiologic and histologic study in dogs.

An external callus is always associated with so-called stress fractures, but a fracture line cannot always be demonstrated by radiologic means. In such instances it is assumed that an undisplaced fracture or microfracture must nevertheless exist for an external callus to form. In this experimental study, 18 beagles were immobilized in a shoulder spica for periods of time ranging from 6 to 32 weeks and then remobilized. At the time of sacrifice, which varied from four to 28 weeks after remobilization was started, eight showed on radiographs an external fusiform bone formation on the distal metacarpal metaphysis during the remobilization period without evidence of a fracture line. Serial histologic examination, in seven metacarpi, also failed to reveal the presence of any break in the bone's continuity. Although this does not exclude the accumulation of microdamage (mechanical fatigue) at such sites, there is sufficient evidence that the circumscribed periosteal reaction occurred at a site of increased stress in the absence of an actual fracture. Consequently, this condition is called a periosteal stress-induced reaction.

Animals↗
PubMed1994

[Serial changes in myocardial perfusion and function after successful percutaneous transluminal coronary angioplasty, examined by stress thallium-201 myocardial scintigraphic and stress radionuclide ventriculographic studies].

In order to study the early and late effects of percutaneous transluminal coronary angioplasty (PTCA), 201Tl myocardial perfusion scintigraphy and exercise 99mTc ventriculography were performed in 25 patients who successfully received PTCA. Before PTCA, reduced myocardial perfusion on stress 201Tl image was observed in all 25 patients, while abnormal regional wall motion during exercise was seen in 22 cases. On stress 201Tl images, reduced myocardial perfusion was demonstrated in 11 cases at 3-7 days after PTCA, but in none at 3 months after the procedure. On the other hand, abnormal exercise regional wall motion was not observed in any case after successful PTCA even in the early phase. When the patients were divided into two groups according to the presence or absence of perfusion abnormalities on stress 201Tl images in the early post-PTCA phase, no difference was seen in clinical and coronary angiographic findings, exercise tolerance, 201Tl uptake score, wall motion score or left ventricular ejection fraction before the procedure. Thus, abnormal myocardial perfusion without impairment of regional left ventricular wall motion is frequently seen in the early post-PTCA phase. But this finding does not necessarily indicate associated myocardial ischemia.

Aged↗
PubMed1977

[The determination of resort and stress-areas by air pollution 2. communication: the evaluation of air pollution in spreadout areas, classification into stress-categories (authors transl)].

To qualify the air pollution by SO2 and particulate matter in wide spreaded areas a method for complex terrain was used in the Austrian Alps. The working model which was chosen is described in report 1. It is possible to classify the investigated area according to stress-categories by adjusting the data. For the qualification of results of measurements for dust fall the criterias were used according to KOFLER and BENGER. Two different situations were considered for the separation of limits for the stress-categories for SO2: areas which are polluted in first line by area sources, and areas which are polluted in first line by point sources.--The limits which were used in the study of Salzburg are introduced and discussed.--According to the method which is described above all municipalities of Tyrol and Salzburg were classified in stress-categories during to their air quality. The results are introduced.

Air Pollution↗