Different Kinds Of Stress Research Articles

Proteomic analyses of the response of cyanobacteria to different stress conditions

Cyanobacteria are significant contributors to global photosynthetic productivity, thus making it relevant to study how the different environmental stresses can alter their physiological activities. Here, we review the current research work on the response of cyanobacteria to different kinds of stress, mainly focusing on their response to metal stress as studied by using the modern proteomic tools. We also report a proteomic analysis of plastocyanin and cytochrome c 6 deletion mutants of the cyanobacterium Synechocystis sp. PCC 6803 grown under copper or iron deprivation, as compared to wild-type cells, so as to get a further understanding of the metal homeostasis in cyanobacteria and their response to changing environmental conditions.

SURFACE MODIFICATION OF METALLIC MATERIALS BY HIGH CURRENT PULSED ELECTRON BEAM

High current pulsed electron beam (HCPEB) has been developing as a useful tool for surface modification of materials. This paper presents our research work on surface modification of metallic materials, such as mold steel, stainless steel and magnesium alloy, with a HCPEB equipment of working parameters as electron energy 27keV, pulse duration ~1µs and energy density ~5J/cm2. Investigations performed have shown that the most pronounced changes of phase-structure state and properties occurring in the near-surface layer. The formation mechanism of surface craters and their evolution regularity are discussed based on the elucidation of non-equilibrium temperature filed and different kinds of stress formed during pulsed electron beam treatment. After the HCPEB treatments, samples show significant improvements in measurements of wear and corrosion resistance.

ROS generation in plants: Boon or bane?

Reactive oxygen species (ROS, partially reduced or activated derivatives of oxygen), are highly reactive and toxic and can lead to oxidative destruction of the cell. ROS production increases when plants are exposed to different kinds of stresses. The chief toxic effect of O2 − and H2O2 resides in their ability to initiate cascade reactions that result in the production of the hydroxyl radical and other destructive species such as lipid peroxides. These dangerous cascades are prevented by efficient operation of the cell's antioxidant defenses. However, in addition to their role as toxic byproducts of aerobic metabolism, recently, a new role for ROS has been identified, i.e. the control and regulation of biological processes, such as growth, cell cycle, programmed cell death, hormone signaling, biotic and abiotic stress responses, and development. This review discusses the biochemical properties and sources and sites of ROS production, ROS-scavenging systems, and the role of ROS as signaling molecules.

Discovery and utilization of favorable genes in wild rice

Wild rice is the closely related wild relatives of cultivated rice. Wild rice provides natural genetic germplasm resources for improving cultivated rice varieties as it possesses many desirable traits and favorable genes, many of which, such as resistance to diseases and insect pests, tolerance to different kinds of stresses and its cytoplasmic male sterility, have been widely used in cultivated rice breeding. In this paper, favorable traits of wild rice germplasm resources and the related genes were summarized, and their utilization potential in rice breeding were also discussed.

Effects of propofol pretreatment on the levels of glutamate and gamma-aminobutyric acid in hippocampus of mentally depressed rats after electro-convulsive therapy

Objective To investigate the effects of propofol pretreatment on the levels of glutamate (Glu) and gamma-aminobytyric acid (GABA) in hippocampus of mentally depressed rats after electro-convulsive therapy.Methods Thirty male 2-3 month old SD rats weighing 200-250 g were randomly divided into 5 groups ( n = 6each) : group Ⅰ control (C) ; group Ⅱ mental depression (D) ; group Ⅲ propofol (P) ; group Ⅳ electric shock (E) and groupV propofol + electric shock (PE). Mental depression was induced by subjecting the animals to different kinds of stresses every day for 21 consecutive days in group Ⅱ - Ⅴ. After mental depression had been induced, the animals received intraperitoneal (IP) propofol 100 mg/kg in group P, electric shock in group E and propefol 100 mg/kg + electric shock in group PE respectively once every 2 days × 6 times. The anxiety-related behavior was assessed by open-field test and scored (the higher the score the better) on the day before induction of mental depression was started (To ,baseline), on the 1st day after mental depression had been induced (T1) and on the 2nd day after treatment (T2). The learning ability and memory were evaluated by Morris water maze at T1 and T2. The animals were killed after the last test and their brains were removed and bilateral hippocampi were isolated for determination of glutamate and GABA contents by high performance liquid chromatography (HPLC).Results The behavior scores and learning ability and memory were significandy decreased in group Ⅱ-Ⅴ as compared with the control group (P<0.05). The behavior scores were significandy higher in group E (Ⅳ) and PE (Ⅴ) than ingroup D (Ⅱ) and P (Ⅲ)(P<0.05). The learning ability and memory were significantly better after treatment (T2) in group PE than in group E (P<0.05). The Glu/GABA ratio in hippocampus was significantly higher but GABA content was significantly lower and Glu content was signficantly higher in group D and P than in group C, E and PE (P<0.05). The Glu/GABA ratio was significantly lower but GABA content was significantly higher and Glu content was significantly lower in group E than in group C and PE (P<0.05).Conclusion Propofol pretreatment can improve the learning ability and memory of the mentally depressed rats under electro-convulsive therapy by regulating the balance between Glu and GABA in the brain. Key words: Propofol ; Electric stimulation therapy; Depressive disorder; Cognition disorders; Glutamie acid ; GABA

Salivary cortisol and IgA levels in patients with myofascial pain treated with occlusal appliances in the short term

In many studies, the endocrinological response of individuals to different kinds of stresses has been tested. There seems to be widespread agreement that stress, depression, disability and dysfunctional illness behaviors are critical aspects of patients suffering from symptoms like pain, arising out of temporomandibular disorders (TMD). We aimed to explore treatment-induced changes in salivary cortisol, IgA and flow rate values in TMD patients suffering from myofascial pain. Temporomandibular disorders patients (n = 39) were randomized into two groups and treated with two different occlusal appliances. Perceived stress regarding family, work, economy, relationships, general health and stress in general was evaluated at baseline according to a verbal scale. Paraffin-stimulated saliva samples were collected before treatment and during follow-up at 6 and 10 weeks. Flow rate was measured immediately after the saliva collection while salivary cortisol and IgA were determined from samples stored at -70 degrees C. No clear association between reported stress and cortisol or IgA values could be observed at baseline. At 10 weeks follow-up, 92% of the patients felt 'better, much better, symptom-free' and no difference was found between the two appliance groups. Cortisol, IgA and flow rate values showed no systematic between appliance groups' differences. All salivary parameters showed interindividual differences but stayed intra-individually on a similar level throughout the study and no statistically significant changes could be observed when comparing before and after treatment levels. To conclude, there were no treatment-induced changes in saliva parameters despite successful appliance therapy in myofascial pain patients.

Diatom teratological forms and environmental alterations: a review

The foremost feature of a diatom is the species-specific ornamentation of the silicon cell wall, which is preserved and faithfully reproduced through the generations. If exposed to different kinds of stress during reproductive processes, the diatom cell outline and striation pattern can change in different ways, producing teratological forms. These modifications can be slight, leading to difficulties in establishing a threshold between normal and teratological cells, or so marked that it is very difficult to recognize whether an unknown form is teratological or whether it belongs to a new species or variety. Teratological forms appear as an accidental effect of environmental stresses, which can be both physical and chemical. Artificial conditions also often lead to the development of teratological forms. Most frequently, diatoms present abnormal valve outline (lack of symmetry, bent, incised, swollen, or notched profile), unusual raphe system (fragmented, displaced, and bifurcated), abnormal striation pattern (irregular, altered, fragmented, and branched), and unusual raphe channel system (distorted, curved, and occasionally doubled back). In this review we analyzed 222 articles, published from 1890 up to 2008, with the aim to correlate the abnormal diatom cell morphology to environmental alterations, in a perspective which can greatly enhance the evaluation of river environmental quality for biomonitoring purposes.

Heme Oxygenase Contributes to Alleviate Salinity Damage inGlycine maxL. Leaves

Plants are frequently subjected to different kinds of stress, such as salinity and, like other organisms, they have evolved strategies for preventing and repairing cellular damage caused by salt stress. Glycine max L. plants were subjected to different NaCl concentrations (0–200 mM) for 10 days. Treatments with 100 and 200 mM NaCl induced ion leakage and lipid peroxidation augmentation, loss in chlorophyll content, and accumulation of O2 •− and H2O2. However, 50 mM NaCl did not modify these parameters, which remains similar to control values. Catalase, superoxide dismutase, and heme oxygenase (HO-1) activities and gene expressions were increased under 100 mM NaCl, while no differences were observed with respect to controls under 50 mM salt. Treatment with 200 mM NaCl caused a diminution in the enzyme activities and gene expressions. Results here reported let us conclude that HO also plays a leading role in the defense mechanisms against salinity.

Photosynthetic efficiency as function of nutrient status in phytoplankton from irrigation and drinking-water reservoirs, determined by photoacoustics

The efficiency of energy storage in photosynthesis is a sensitive indicator of different kinds of stress to which plants are exposed. In this study, phytoplankton samples were obtained from irrigation and drinking-water reservoirs differing in trophic status, and their photosynthetic efficiency was examined using the photoacoustic method. We examined changes in photosynthetic energy storage efficiency over time in natural samples collected from the field, and following their enrichment with nitrogen and phosphorus. It was evident that as phytoplankton grew, both nutrients became depleted, nitrogen earlier than phosphorus.

A temporal analysis of the relationships between social stress, humoral immune response and glutathione-related antioxidant defenses

The exposure to different kinds of stress impacts on the reactive oxygen species production with potential risk to the integrity of the tissues. Psychological or biological stress is responsible for a significant increase in the oxidative stress markers and also for activation of the antioxidant defense system. In this study, we analyzed the relationships between social stress, humoral immune response and glutathione-related antioxidant defenses. Groups of male Swiss mice were subjected to different lengths of social stress exposure (social confrontation) which varied from 1 up to 13 days. As a biological stressor, 10 9 sheep red blood cells (SRBC)/mL were injected by intraperitoneal route. As controls, animals not subjected to social stress and/or injected with vehicle solution were used. The serum samples and the cerebral cortex were collected at 4 h, 3, 5, 7, 9, 11, and 13 days after the end of social confrontation. The results indicated that the antioxidant enzymes activities were affected by psychological as well as by biological stressor. These alterations were dependent on the timing of stress exposure which resulted in a positive or in a negative correlation between the antibody titres to SRBC and antioxidant enzymes. We also discuss the possible role of SRBC injection in the modulation of the effects of psychosocial stress on antioxidant metabolism.

A ribosome-inactivating protein (curcin 2) induced from Jatropha curcas can reduce viral and fungal infection in transgenic tobacco

A new kind of ribosome-inactivating protein (curcin 2), induced by several different kinds of stress from Jatropha curcas leaves, under the control of the CaMV (cauliflower mosaic virus) 35S promoter, was introduced into the tobacco genome by Agrobacterium tumefaciens-mediated transformation method. The curcin 2 protein was only detected in the transgenic tobacco plantlets transformed with the cur2p fragment (coding premature curcin 2 protein), but not in the plantlets with the cur2m fragment (coding mature curcin 2 protein). The T1 population of the transgenic lines shows an increased tolerance to tobacco mosaic virus (TMV) and a fungal pathogen Rhizoctonia solani by delaying the development of systemic symptoms of TMV and reducing the damage caused by the fungal disease. The increases of the tolerances correspond to the curcin 2 level in the transgenic plants.

Differential effects of psychological and physical stress on the sleep pattern in rats.

In the present study, we investigated the acute effects of 2 different kinds of stress, namely physical stress (foot shock) and psychological stress (non-foot shock) induced by the communication box method, on the sleep patterns of rats. The sleep patterns were recorded for 6 h immediately after 1 h of stress. Physical and psychological stress had almost opposite effects on the sleep patterns: In the physical stress group, hourly total rapid eye movement (REM) sleep and total non-REM sleep were significantly inhibited, whereas psychological stress enhanced hourly total REM sleep but not total non-REM sleep. Further results showed that total REM sleep, total non-REM sleep, total sleep and the total number of REM sleep episodes in 5 h were reduced, and that sleep latency was prolonged compared to the control group. On the other hand, in the psychological stress group, the total REM sleep in 5 h was increased significantly due to the prolongation of the average duration of REM sleep episodes and reduced REM sleep latency. In addition, the plasma of corticosterone increased significantly after physical stress but not after psychological stress. These results suggested that the sleep patterns, particularly the patterns of REM sleep following physical and psychological stress, are probably regulated by 2 different pathways.

Diverse stress signals activate the C1 subgroup MAP kinases of Arabidopsis

Mitogen-activated protein kinase (MAPK) cascades play an important role in mediating stress responses in plants. In Arabidopsis, 20 MAPKs have been identified and classified into four major groups (A–D). Little is known about the role of group C MAPKs. We have studied the activation of Arabidopsis subgroup C1 MAPKs (AtMPK1/AtMPK2) in response to mechanical injury. An increase in their kinase activity was detected in response to wounding that was blocked by cycloheximide. Jasmonic acid (JA) activated AtMPK1/AtMPK2 in the absence of wounding. Wound and JA-induction of AtMPK1/2 kinase activity was not prevented in the JA-insensitive coi1 mutant. Other stress signals, such as abscisic acid (ABA) and hydrogen peroxide, activated AtMPK1/2. This report shows for the first time that regulation of AtMPK1/2 kinase activity in Arabidopsis might be under the control of signals involved in different kinds of stress.

A Novel Heat Shock Transcription Factor Family in Entamoeba histolytica

The HSTF is a master molecule involved in the transcriptional control of several genes during different types of stress. This transcription factor is a very conserved protein identified in different organisms from bacterial to human. Entamoeba histolytica is the protozoan responsible for the human amoebiasis. This parasite is exposed to different kind of stress as changes in the pH, temperature, drugs, all that situations in where the parasite needs survive. Here we identified and isolated a novel gene family of HSTFs in the protozoan parasite E. histolytica. Three members that we called Ehhstf1, Ehhstf2 and Ehhstf3 compose this family. Amino acid alignments and domain architecture analysis revealed that the EhHSTFs presents a conserved DNA-binding domain composed of approximately 25 residues. Interestingly this domain is shorter than the domain of the human, mouse and yeast HSTFs. Heterologous antibodies recognized four peptides of 73, 66, 47 and 23 kDa in total extracts from trophozoites growth under normal conditions. The 73, 47 and 23 kDa peptides increased their intensity when the cells were growth at 42°C by 2 h. All results together demonstrate that the amoeba present HSTFs, which may be, controlled the gene expression of this parasite under different stress situations.

Gestation linked radical oxygen species fluxes and vitamins and trace mineral deficiencies in the ruminant

In mammals, radical oxygen species (ROS) are essential factors of cell replication, differentiation and growth (oxidative signal), notably during gestation, but are also potentially damaging agents. In Women, ROS play a role in remodeling of uterine tissues, implantation of the embryo, settlement of the villi and development of blood vessels characteristic of gestation. The body stores of vitamins and minerals of gestating females are used to keep ROS fluxes at a level corresponding to oxidative signals and to prevent an imbalance between their production and scavenging (oxidative stress), which would be detrimental to the mother and fetus. There is some evidence that, although based on different regulatory mechanisms, most of the effects of ROS reported in humans also occur in pregnant ruminant females, some of which have been actually reported. Many vitamins and trace elements have dual effects in the organism of mammals: (a) they are involved in the control of metabolic pathways or/and gene expression, (b) but most of the time they also display ROS trapping activity or their deficiencies induce high rates of ROS production. Deficiencies induce different disorders of gestation and can be induced by different kinds of stress. An example is given, corresponding to the decreased contents of cobalt of forages, when exposed to sustained heavy rains, so that the supply of vitamins B12 to the organism of the ruminant that grazes them is reduced and failure of gestation is induced. Outdoor exposure of ruminants to adverse climatic conditions by itself can increase the vitamin and trace element requirements. Adaptation of production systems taking into account these interactions between gestation and sources of stress or change of the quality of feeding stuffs as well as further developments of knowledge in that field is necessary to promote sustainable agricultural practices.

Budding yeast Saccharomyces cerevisiae as a model to study oxidative modification of proteins in eukaryotes.

The budding yeast Saccharomyces cerevisiae is a well studied unicellular eukaryotic organism the genome of which has been sequenced. The use of yeast in many commercial systems makes its investigation important not only from basic, but also from practical point of view. Yeast may be grown under both aerobic and anaerobic conditions. The investigation of the response of eukaryotes to different kinds of stresses was pioneered owing to yeast and here we focus mainly on the so-called oxidative stress. It is a result of an imbalance between the formation and decomposition of reactive oxygen species increasing their steady-state concentration. Reactive oxygen species may attack any cellular component. In the present review oxidation of proteins in S. cerevisiae is analyzed. There are two connected approaches to study oxidative protein modification - characterization of the overall process and identification of individual oxidized proteins. Because all aerobic organisms possess special systems which defend them against reactive oxygen species, the involvement of so-called antioxidant enzymes, particularly superoxide dismutase and catalase, in the protection of proteins is also analyzed.

Characterization of Total Safe Operating Area of Lateral DMOS Transistors

The total safe operating area (SOA) of LDMOS transistors is discussed. It is shown that the transistors are subjected to different kinds of stresses, yielding a combination of electrical and thermal degradation and/or failure modes. A methodology to build the total SOA for LDMOS transistors is highlighted and is experimentally verified on a 40-V LDMOS implemented in a

Heat Shock–Induced Enhancement of Osteoblastic Differentiation of hTERT‐Immortalized Mesenchymal Stem Cells

Heat shock (HS)-induced stress response in human cells results in a variety of biological effects and is known to induce the transcription of heat-shock proteins, which help the cells to cope with different kinds of stress. We have studied the effects of HS on the differentiation of human mesenchymal stem cells (hMSCs) into osteoblastic cells. As a model for hMSCs we used a telomerase-immortalized hMSC line designated hMSC-TERT. Cells were exposed to 1 h HS at 41 degrees C, 42.5 degrees C, or 44 degrees C prior to incubation in a medium containing either 10(-8) M 1alpha,25-dihydroxy-vitamin-D(3) (calcitriol) or 10(-8) M calcitriol, 50 microg/mL L-ascorbic acid, and 10 mM beta-glycerophosphate followed by an analysis of induction of osteoblast differentiation and the formation of mineralized matrix, respectively. Our results indicate that the exposure of cells to mild heat stress enhances the extent of differentiation of hMSCs by 12% to 42%. These effects are an expression of the phenomenon of mild stress-induced hormesis.

Correlation of nanoindentation measurements of nickel made using geometrically different indenter tips

Nanoindentation is a widely used technique to measure the mechanical properties of coatings and thin films whose thickness ranges from nanometers to micrometers. Measurement of mechanical properties like hardness and modulus of elasticity of the sample being indented depends on the geometry of the indenter. A change in tip geometry is an added characterization advantage for reliability in design of structural components for mechanical systems. Different kinds of stresses imposed by geometrically different indenters give an indication of material behavior when multiple stresses act on a surface. Tip calibration and analytical simulations of these experiments have been performed using the finite element method. Hardness and modulus values differ for geometrically different indenters. In this paper, an attempt is made to correlate hardness values obtained using three indenters of different geometries and to understand deformation mechanisms of nickel in nanoindentation. The results are examined on the basis of geometrically necessary deformation mechanisms theory [Nix WD, Gao H. J Mech Phys Solids 1998;46:411].

Oxidative stress is the new stress

Emotional stress may increase anxiety, but in mice, a different kind of stress—oxidative stress—may also contribute to anxious behavior.