Human stress phase estimation method

Human stress reaction phases have been studied in psychoemotional stress. Objective criteria for stress reaction phases associated with distinctive changes in heart rhythm variability and cognitive function have been revealed using Stroop-test computerized variant.     

Long-Term and Transgenerational Effects of Stress Experienced during Different Life Phases in Chickens (Gallus gallus)

Stress in animals causes not only immediate reactions, but may affect their biology for long periods, even across generations. Particular interest has been paid to perinatal stress, but also adolescence has been shown to be a sensitive period in mammals. So far, no systematic study has been performed of the relative importance of stress encountered during different life phases. In this study, groups of chickens were exposed to a six-day period of repeated stress during three different life phases: early (two weeks), early puberty (eight weeks) and late puberty (17 weeks), and the effects were compared to an unstressed control group. The short-term effects were assessed by behaviour, and the long-term and transgenerational effects were determined by effects on behavior and corticosterone secretion, as well as on hypothalamic gene expression. Short-term effects were strongest in the two week group and the eight week group, whereas long-term and transgenerational effects were detected in all three stress groups. However, stress at different ages affected different aspects of the biology of the chickens, and it was not possible to determine a particularly sensitive life phase. The results show that stress during puberty appears to be at least equally critical as the previously studied early life phase. These findings may have important implications for animal welfare in egg production, since laying hens are often exposed to stress during the three periods pinpointed here.     

Influence of Oxides on the Stress Evolution and Reversibility during SnOx Conversion and Li‐Sn Alloying Reactions

The effect of varying the oxygen content in Sn and SnO_x films during potential dependent SnO_x conversion reactions and Li_ySn alloying relevant to Li ion battery anodes is examined. For metallic Sn films, the stresses and stability of the films are controlled by Li alloying reactions. Small, non‐contacting separated Sn particles exhibit higher electrochemical stability relative to more continuous polycrystalline films with larger particles. Metallic Sn particles develop tensile stress during Li_ySn de‐alloying as porous structures are formed. The amount of stress associated with lithiation and delithiation of well‐separated metallic particles decreases as a porous, easy to lithiate, material forms with cycling. During the lithiation of oxides, conversion reactions (SnO_x → Sn) and the lithiation of the metallic Sn control the stress responses of the films, leading to highly potential‐dependent stress development. In particular, evidence for a multistep electrochemical mechanism, in which partially reversible lithiation of the oxygen‐containing phases is conjoined with a fully reversible lithiation of the metallic phases of the Sn, is found. The electrochemical stress analysis provides new insight into these mechanisms and delineates the extent of the reversibility of lithiation and conversion reactions of oxides.     

Signal transduction enzymes of vertebrate photoreceptors

A flash of light initiates a cascade of biochemical reactions inside vertebrate photoreceptor cells, culminating in hydrolysis of intracellular cyclic GMP and hyperpolarization of the cell. The cell recovers by shutting down this cascade and resynthesizing cGMP. Many of the reactions responsible for the excitation and recovery phases of the photoresponse have been identified. Here I review some characteristics of the proteins that participate in these reactions.     

Changes in energy metabolism and contractile function of the heart during development of focal necroses of the myocardium

It has been established that the changes in hypophysial-adrenal reactions, metabolism and cardiac structures and functions have a phasic character. The study of the biorhythm of eosinophil blood level has allowed the determination of the temporary parameters of damage and recovery phases.     

Eutectic phase in water-ice: a self-assembled environment conducive to metal-catalyzed non-enzymatic RNA polymerization

Information and catalytic polymers play an essential role in contemporary cellular life, and their emergence must have been crucial during the complex processes that led to the assembly of the first living systems. Polymerization reactions producing these molecules would have had to occur in aqueous medium, which is known to disfavor such reactions. Thus, it was proposed early on that these polymerizations had to be supported by particular environments, such as mineral surfaces and eutectic phases in water-ice, which would have led to the concentration of the monomers out of the bulk aqueous medium and their condensation. This review presents the work conducted to understand how the eutectic phases in water-ice might have promoted RNA polymerization, thereby presumably contributing to the emergence of the ancient information and catalytic system envisioned by the 'RNA-World' hypothesis.     

The pathway tools pathway prediction algorithm

The PathoLogic component of the Pathway Tools software performs prediction of metabolic pathways in sequenced and annotated genomes. This article provides a detailed presentation of the PathoLogic algorithm. The algorithm consists of two phases. The reactome inference phase infers the reactions catalyzed by the organism from the set of enzymes present in the annotated genome. The pathway inference phase infers the metabolic pathways present in the organism from the reactions catalyzed by the organism. Both phases draw on the MetaCyc database of metabolic reactions and pathways. MetaCyc contains two data fields to support pathway inference: the expected taxonomic range of each pathway, and a list of key reactions for pathways. These fields have significantly increased the predictive accuracy of PathoLogic.     

Cysteine residues as catalysts for covalent peptide and protein modification: a role for thiyl radicals?

Cysteine thiyl radicals engage in reversible intramolecular hydrogen-transfer reactions with amino acid residues in peptides and proteins. These reactions can be experimentally demonstrated through covalent hydrogen-deuterium exchange when experiments are carried out in (2)H2O. To this end, hydrogen-transfer reactions have been observed between cysteine thiyl radicals and glycine, alanine, serine, valine and leucine in both model peptides and a protein, insulin. The relevance of such reactions for protein oxidation under conditions of oxidative stress is discussed.     

The physiological reactions to stress in 3 strains of rats]

We have studied the resistance of Wistar, August, Fisher male rats to 2- and 24-hours immobilization by vegetative and behavioral reactions. The difference in the resistance has been observed both between the three lines of rats and within one particular line. The lowest resistance to stress has been demonstrated by Fisher rats, the highest by Wistar rats. The correlation between emotional reactivity of rats and their response to stress has been shown.     

羰基毒害在糖尿病晚期并发症中的作用

动物机体组织的氧化紧张损伤和老化交联是糖尿病晚期并发症中神经病变、动脉粥样硬化、风湿性关节炎、肾病变、白内障等老化慢性疾病的共同特征.对氧化紧张到底是糖尿病晚期并发症的初始原因还是糖尿病组织衰变的次级诱因提出了探讨.结果表明糖尿病患者机体和血浆中的糖氧化产物及脂类过氧化物的增多表明病患者体内氧化紧张的加强;然而,它们中的某些产物与氧化紧张并不相关;此外,其它一些氧化紧张的直接指标,如氨基酸的氧化,在糖尿病患者的皮肤胶原中也并没有增多.因此,对于糖尿病患者中蛋白质化学修饰的现象,用活性羰基的毒化超过其系统解毒能力的观点来解释更合适.这种在氧化或非氧化反应中形成的不饱和羰基化合物在体内总是以相对恒定的浓度存在,因而在糖尿病中,由羰基毒害引起组织中糖类和脂类衍生物的增长可以被认为是生物化学动力学的一种必然结果.     

Modeling of DNAPL-Dissolution, Rate-Limited Sorption and Biodegradation Reactions in Groundwater Systems

This article presents an approach for modeling the dissolution process of single component dense non-aqueous phase liquids (DNAPL), such as tetrachloroethene and trichloroethene, in a biologically reactive porous medium. In the proposed approach, the overall transport processes are conceptualized as three distinct reactions. Firstly, the dissolution (or dissolving) process of a residual DNAPL source zone is conceptualized as a mass-transfer limited reaction. Secondly, the contaminants dissolved from the DNAPL source are allowed to partition between sediment and water phases through a rate-limited sorption reaction. Finally, the contaminants in the solid and liquid phases are allowed to degrade by a set of kinetic-limited biological reactions. Although all of these three reaction processes have been researched in the past, little progress has been made towards understanding the combined effects of these processes. This work provides a rigorous mathematical model for describing the coupled effects of these three fundamental reactive transport mechanisms. The model equations are then solved using the general-purpose reactive transport code RT3D (Clement, 1997).     

Oxidative burst and cell death in ozone-exposed plants

The phytotoxic air pollutant ozone spontaneously generates reactive oxygen species (ROS) in the leaf apoplast, provokes hypersensitive response-like lesions and induces defence reactions that significantly overlap with pathogen and other oxidative stress responses. Consequently, ozone has been used as a tool to unravel in planta ROS-induced plant defence and cell death mechanisms. Ozone exposure stimulates an oxidative burst in leaves of sensitive plants, resulting in the generation and accumulation of hydrogen peroxide or superoxide anions in distinct species. Accumulation of these ROS precedes the induction of cell death, and both responses co-occur spatially in the periveinal regions of the leaves. The review summarizes some of the recent results that have been obtained concerning the molecular basis of apoplastic ROS production in monocot and dicot species. Signal molecules, in particular ethylene and salicylic acid, control and potentiate the oxidative burst and subsequent cell death in its initiation and propagation phases while jasmonate leads to lesion containment. Amplification mechanisms that result in the production of excess ROS and hypersensitive cell death are discussed as major factors in ozone sensitivity of plant species and cultivars.     

Toxoplasma gondii: cold stress-induced modulation of antibody responses.

Physical or psychological stressors have been shown to have significant consequences in the immune function and the outcome of disease in human and animal models. Recent work has demonstrated that products released during stress, such as glucocorticoids and catecholamines, can profoundly influence the in vitro growth of pathogens by modulating immune responses. The present study examined the effects of a physical stressor (cold stress) on antigens of Toxoplasma gondii that elicits an antibody-mediated immune response during the acute and chronic phases of infection. Sera obtained from different groups of mice subjected to cold stress during the acute and chronic phases of T. gondii infection were used to measure the levels of antibodies and to localize by Western blot the dominant antigens eliciting IgG and IgM antibody responses. Serum antibodies collected from stressed and infected mice recognized antigens different from those recognized by infected mice without stress. During the acute phase, a stronger IgM antibody response against antigens of 30, 42, 54, and 60 kDa was detected in stressed animals at 3 weeks postinfection. In addition, a 5-kDa antigen was specifically detected in mice subjected to stress during the acute and chronic phases of infection. Levels of specific IgG were increased in infected and in infected and stressed animals that underwent stress in the chronic phase. IgM production did not increase following cold stress in the chronic phase. These results suggest that the strong antibody response in stressed animals is associated with longer parasite persistence in circulation. Stress modulated not only the host immune response but also the ability of parasite antigens to elicit specific antibody responses by the host.     

Stress genes and species survival

Stress genes can be ascribed to have been generated by the organism for their intrinsic urge to survive against the changing environmental odds, during the evolutionary process. This concept has been supported by a large number of reports describing individual types of phenomena. These have been reconciled and globalised in terms of their relevance in this article. Supporting evidences have been drawn from the literature which indicated that by using different types of inducer one can express heat shock proteins. Similarly, several types of stress inducers, such as calorie restriction, LPS stimulation and Staphylococcal Protein-A stimulation, it was possible to induce a wide array of biological, biochemical and immunological reactions. Such biological reactions rendered protection against toxic, carcinogenic, metabolic, as well as biological stresses induced by microorganisms. Heat shock proteins have been implicated as having a role in providing resistance to the host against different types of stressors. In this article, some mechanistic schemes have been proposed as possible pathways globalising such phenomena. A minute amount of stress inducers has been observed to have helped expression of stress resistance genes, providing increased capability to the host to protect itself against myriads of both biotic and abiotic stressors. More understanding about such phenomena would help in keeping our physiological systems vigilant and our bodies healthy, fighting out the stress-related events effectively.     

Modeling of DNAPL-Dissolution,Rate-Limited Sorption and Biodegradation Reactions in Groundwater Systems

This article presents an approach for modeling the dissolution process of single component dense non-aqueous phase liquids (DNAPL), such as tetrachloroethene and trichloroethene, in a biologically reactive porous medium. In the proposed approach, the overall transport processes are conceptualized as three distinct reactions. Firstly, the dissolution (or dissolving) process of a residual DNAPL source zone is conceptualized as a mass-transfer limited reaction. Secondly, the contaminants dissolved from the DNAPL source are allowed to partition between sediment and water phases through a rate-limited sorption reaction. Finally, the contaminants in the solid and liquid phases are allowed to degrade by a set of kinetic-limited biological reactions. Although all of these three reaction processes have been researched in the past, little progress has been made towards understanding the combined effects of these processes. This work provides a rigorous mathematical model for describing the coupled effects of these three fundamental reactive transport mechanisms. The model equations are then solved using the general-purpose reactive transport code RT3D (Clement, 1997).     

Delta-sleep-inducing peptide (DSIP) as a factor facilitating animals' resistance to acute emotional stress

Delta-sleep-inducing peptide (DSIP) effects on resistance to acute emotional stress induced by electric stimulation of the ventromedial hypothalamus and skin of immobilized rats have been investigated. On the basis of the pattern of cardiovascular reactions, three groups of rats were distinguished: resistant, adapted, and predisposed to the experimental emotional stress. It is shown that DSIP injections increase animals' resistance to acute emotional stress. DSIP also changes the vascular reactivity to episodic emotiogenic stimulations. It is revealed that, after DSIP application, the absence of vascular reactions to emotiogenic ventromedial hypothalamic and electro-skin stimulations significantly increased.     

Reaction cavities of liquid and solid phases of a long n-alkane, n-nonadecane, as probed by the regio- and stereo-chemical fates of two singlet radical pairs.

The regio- and stereo-chemistries of photo-Fries reactions of 1-naphthyl (R)-2-phenylpropanoate ((R)-1) and photo-Claisen reactions of 1-naphthyl (R)-1-phenylethyl ether ((R)-2) have been investigated in the liquid and solid phases of n-nonadecane. The results are compared with those obtained in a lower and higher viscosity liquid n-alkane. Irradiation of (R)-1 yields a prochiral singlet 1-naphthoxy-1-phenylethyl radical pair (radical pair B) indirectly, after decarbonylation of the initially formed chiral singlet 1-naphthoxy-2-phenylpropanoyl radical pair (radical pair A). Radical pair B is generated directly upon lysis of the excited singlet state of (R)-2. The restricted environments of the solid phases enable both the directly and indirectly formed radical pairs to maintain much (but not all) of the memory of their initial orientations. Thus, the in-cage combination products from indirectly formed radical pair B contain up to 33% enantiomeric excess. However, the combinations of directly formed radical pair B lack complete stereo-specificity due to their disturbing influence on their local environments in the solid phases. A discussion of the dynamics of the radical pair motions in the different environments is presented.     

Proton transfer during the reaction between fully reduced cytochrome c oxidase and dioxygen: pH and deuterium isotope effects.

The pH dependence of proton uptake and electron transfers during the reaction between fully reduced cytochrome c oxidase and oxygen has been studied using the flow-flash method. Proton uptake was monitored using different pH indicators. We have also investigated the effect of D2O on the electron-transfer reactions. Proton uptake was biphasic throughout the pH range studied (6.3-9.3), and the decrease of the observed rate constants at increasing pH could be described by titration curves with pKa values of 8-8.5. Of the four phases resolved in the redox reaction, the rate constants for the first two were independent of pH, whereas that of the third decreased at increasing pH with a pKa of 7.9. All phases except the first were slower in D2O than in H2O. The values obtained for kH/kD were 1.0 for the first phase, 1.4 for the second and third phases, and 2.5 for the fourth phase. We suggest from these results that the fast phase of proton uptake is initiated by the second phase of the redox reaction and that this step includes a partially rate-limiting internal proton transfer. The third and fourth phases of the redox reaction are suggested to be rate limited by proton uptake from the medium. The pH dependencies of the proton uptake reactions are consistent with the participation of a titrable group in the protein in proton transfer from the medium to the oxygen-binding site.