A study of the polymorphism and ethnic distribution differences of human serum paraoxonase

The enzyme serum paraoxonase shows a polymorphism in Europeans which is governed by two alleles. The first allele has a gene frequency p_low of 0.716–0.777, and is manifested as a low activity group in homozygotes. More than 50% of all European test subjects can be included in this group. A second allele with a gene frequency q_high of 0.223–0.284 was found in typical European distributions and is manifested in both the form of a second heterozygotic and a third homozygotic group with high activities. The Hardy-Weinberg rule for a two-allele model is valid for the distribution. The gene frequency p_low of the first allele decreases as one moves from Europe in the direction of Africa and Asia. In typical Mongoloid and Negroid collectives, less than 10% of the population can be included in the low-activity group, a group which is not even demonstrable in the Aborigines of Australia. The serum paraoxonase of the Aborigine population shows unimodal distribution. The validity of the Hardy-Weinberg rule for a three-allele model must be rejected in all examined collectives. Human serum paraoxonase shows neither age-related changes in activity nor sex-dependent activity differences.     

Mouse strain differences in autonomic responses to stress

In humans, anxiety disorders are often accompanied by an overactive autonomic nervous system, reflected in increased body temperature (BT) and heart rate (HR). In rodents, comparable effects are found after exposure to stress. These autonomic parameters can give important information on stress and anxiety responses in mice. In the present experiments, stress reactivity of three frequently used mouse strains [129 Sv/Ev, Swiss Webster (SW) and C57 BL/6] was assessed using their autonomic stress responses. BT, HR and activity were telemetrically measured. Undisturbed circadian rhythms already showed clear differences between the mouse strains. Hereafter, autonomic responses to stressors with increasing intensity were measured. Strain differences were found in magnitude and duration of the stress responses, especially after high-intensity stressors. Generally, C57BL/6 mice showed the largest autonomic response, SW the lowest and the 129Sv/Ev the intermediate response. Interestingly, the observed ranking in autonomic stress response does not match the behavioral stress responsivity of these strains. Finally, sensitivity to the anxiolytic diazepam (0, 1, 2, 4 and 8 mg/kg) was tested using the stress-induced hyperthermia paradigm. Pharmacological sensitivity to diazepam differed between the strains with the 129Sv/Ev being most sensitive. These studies show that simultaneous measurement of behavioral and autonomic parameters under stressful conditions contributes considerably to a better interpretation of anxiety and stress levels in mice.     

The ethnic question in an environment of insecurity: the Kurds in Turkey

This article examines the effect that a poor structural context, what we term an "environment of insecurity", has on the Kurdish ethnic nationalist mobilization in Turkey. The empirical evidence for this analysis is based on data from the 1993 Turkish Demographic and Health Survey [TDHS]. The data provide, to the best of our knowledge, the first reliable and representative figures on the situation of Kurds in Turkey. Our key claim is that the Kurdish population in Turkey is relatively much worse off than the Turkish population in the country. This claim is strongly supported by the data. Many other factors also account for the ethnic nationalist mobilization, but we argue that the Turkish Kurds' environment of insecurity, materially and non-materially, stands out as a key package of both causal and intermediate variables behind the ethnic revival.     

The AC conductivity of human sweat ducts as the dominant factor in the sub-THz reflection coefficient of skin

The helical nature of human sweat ducts, combined with the morphological and dielectric properties of skin, suggests electromagnetic activity in the sub-THz frequency band. A detailed electromagnetic simulation model of the skin, with embedded sweat ducts, was created. The model includes realistic dielectric properties based on the measured water content of each layer of skin, derived from Raman Spectroscopy. The model was verified by comparing it to measurements of the reflection coefficient of the palms of 13 volunteers in the frequency band 350–410 GHz. They were subjected to a measurement protocol intended to induce mental stress, thereby also activating the sweat glands. The Galvanic Skin Response was concurrently measured. Using the simulation model the optimal ac-conductivity for each measurement was found. The range of variation for all subjects was found to be from 100 S/m to a maximum value of 6000 S/m with averages of 1000 S/m. These are one order of magnitude increase from the accepted values for water at these frequencies (~100 s/m at 100 GHz). Considering the known biochemical mechanism for inducing perspiration, we conclude that these ac-conductivity levels are probably valid, even though the real time measurements of sweat ac-conductivity levels inside the duct are inaccessible.     

The cytological responses of tomato-seedling cotyledons to chilling and the influence of membrane modifications upon these responses

Summary Tomato seedlings were exposed to 3 days of chilling at 5 °C in both the presence and absence of 5 mM ethanolamine. An array of pathological responses could be seen at both the light and electron microscope levels: apparent loss of cell turgor, vacuolization, reduction in the apparent volume of both the cytoplasm and the vacuolar protein bodies, apparent deposition of new material in the cell walls, general disorganization of organelles, especially plastids, and a general loss of cytoplasmic structure. Chilling injury was less pronounced in ethanolamine-treated cotyledonary tissues which appeared to have normal turgor and cell shape at the light microscope level and better preserved organelles at the ultrastructural level. Protection by ethanolamine at the ultrastructural level was most pronounced for the cytoplasm, the mitochondria, and the cell walls. Dead cells were seen with both treatments but were 2–3 times as numerous in the chilled-only tissue.     

斑马鱼热耐受性对温度驯化的响应及其性别差异

为了探究斑马鱼(Danio rerio)热耐受性对温度驯化的响应及其性别差异,将性成熟斑马鱼分别于适温(28℃)、低温(20℃)和高温(34℃)下驯化14 d,之后测定不同温度驯化下雌鱼和雄鱼的临界高温(critical thermal maxima,CTmax)、致死高温(lethal thermal maxima,LTmax)、临界低温(critical thermal minima,CTmin)、致死低温(lethal thermal minima,LTmin)等热耐受性参数.结果表明:驯化温度对雄鱼和雌鱼的所有热忍耐参数(CTmax、LTmax、CTmin和LTmin)均影响显著(P<0.05),并且驯化温度和性别对热耐受性参数的影响具有交互作用(P<0.05).适温(28℃)驯化下,雌鱼与雄鱼各个热忍耐参数相比无显著差异(P> 0.05);低温(20℃)驯化下雌鱼的耐高温能力强于雄鱼,而高温(34℃)驯化下雌鱼的耐低温能力弱于雄鱼.结果提示:繁殖适温下雌雄斑马鱼的热耐受性趋于一致,而非繁殖适温下二者的热耐受性出现分化.     

Individual differences in responses of Norway rats to social induction of food preferences

Each of 36 observer rats was: (1) exposed to a demonstrator rat that had eaten an unpalatable, cayenne-pepper-flavored diet (Diet Cay), then tested to determine its willingness to eat Diet Cay and (2) exposed to a demonstrator rat that had eaten a palatable diet (Diet NPT) to which the observer had previously learned an aversion, then tested to determine its willingness to eat Diet NPT. In both instances, some observers ate substantial amounts of the diet that their respective demonstrators had eaten, while other observers did not. No consistency was found across the two situations in the relative susceptibility of individual observer rats to social influences on their food choices. In a second experiment, observer rats interacted, at 3 day intervals, with demonstrator rats that had each eaten different diets. After each interaction, all observers were given a choice test to determine their preferences for the diet that their demonstrators had eaten. Again, there was no consistency in the relative strength of individual observer rats' socially induced preferences for diets fed to demonstrators. Stable individual differences in magnitude of susceptibility to social influence on food preference did not account for a detectable proportion of observed variance in diet selection.     

The manipulation of ethnicity: from ethnic cooperation to violence and war in Yugoslavia

The story of the failure of bargaining among ethnic élites and of international diplomacy is well known. What has not been well explained is the spread and support for xenophobic nationalism and ethnic violence among people who had lived cooperatively for thirty-five years. I draw on key ideas of four views on ethnicity and ethnic conflict, and add the concept of cognitive frame in ethnic relations. Yugoslavs possessed two ethnic frames in their minds, an ethnic cooperation and peace frame for normal times, and a crisis frame anchored in World War II memories. Élite contention and mass media propaganda awakened the dormant crisis frame, suppressed the normal frame, and spread insecurity and fear. I explain why ethnic manipulation succeeded, people believed falsehoods, voted for nationalists, how moderates were purged and why men in militias killed innocent civilians.     

Evolutionary responses of Drosophila melanogaster life history to differences in larval density

The study examined the effects of evolution at two different larval densities on pre-adult and adult fitness traits. Five replicate selection lines each were cultured at either 50 or 150 larvae per vial, avoiding selection on development time, age at breeding or for adaptation to adult density, one or more of which factors has been a confounding variable in previous studies. Low density selection lines evolved extended development times at both growth densities. The extended development times were associated with greater adult body size at the lower growth density only, and particularly in females. The lines did not differ significantly in larval competitive ability at either growth density. At neither growth density did the early adult fertility of females or the lifespan of either sex differ between the lines from the two selection regimes, but at the lower growth density the late fertility of low density line females was significantly enhanced. The results suggest that larval density does have important effects on the expression and resolution of life history trade-offs in Drosophila melanogaster, but that these may be somewhat different from those reported in previous studies.     

Effect of bilateral carotid cooling on thermal responses during cycling and arm cranking work due to identical oxygen consumption

1. During the control, tympanic temperature (T_ty), skin blood flow (SkBF), local sweating rate (LSR) and heart rate (HR) of the AC were markedly higher than those of the BE. No significant differences were finally observed in rectal (T_re) and mean skin (T_sk) temperatures or oxygen uptake (VO₂). In contrast, mechanical work efficiency (ME) was significantly higher in the BE than in the AC.

2. During ice cooling, T_ty and the increasing rate in T_ty began to be suppressed at 25–35 min after the beginning in both kinds of work. During the AC, SkBF, LSR, HR and mean T_sk in the ice cooling tended to be lower compared those in the control. There were no significant difference between the control and the ice cooling in ME, VO₂ or T_re in either kind of work.     

不同小麦品种对UV-B辐射增强响应的生理特性差异

研究了大田条件下模拟增强UV-B辐射（500 KJ·m^-2,相当于昆明地区臭氧层减少20%）对10个小麦品种生理指标的影响以及小麦对UV B辐射响应的种内差异.结果表明,10个供试小麦品种中有6个品种的叶绿素含量显著下降,叶绿素a降低的程度大于叶绿素b,从而导致叶绿素a/b的比率下降.UV-B对小麦叶片内MDA和类黄酮的影响也具有种内差异,有5个品种的MDA含量显著上升, 2个品种的MDA含量显著下降;4个品种的类黄酮含量显著增加,2个品种的类黄酮含量显著减少.叶绿素和类黄酮含量变化与MDA含量均呈显著负相关关系,类黄酮与小麦UV-B抗性之间存在密切联系.     

The adaptive response of human skin to the savanna

In the early stage of human evolution, as the hominids began to inhabit the savanna mosaic in Africa some three or four million years ago, a functional complex of skin features contributed to their effective exploitation of resources and survival in the new environment. Thermal radiation from the sun combined with internally generated heat from muscular effort posed problems of thermoregulation. As a mechanism for dissipating body heat and maintaining brain temperature, eccrine sweat glands throughout the body surface combined with reduction in body hair enhanced the evaporative cooling effects of sweating. As body hair diminished, deeply pigmented skin was selected for as a protection against harmful ultraviolet radiation. When human populations left the equatorial regions of Africa, the adaptive significance of deeply pigmented skin may have shifted in response to other factors, such as latitude, diet and cultural pratices. We view the structure and function of human skin within a comparative and evolutionary framework that focuses on the environment in which the hominids evolved.     

Direct estimation of entropy loss due to reduced translational and rotational motions upon molecular binding

The entropic cost due to the loss of translational and rotational (T-R) degree of freedom upon binding has been well recognized for several decades. Tightly bound ligands have higher entropic costs than loosely bound ligands. Quantifying the ligand's residual T-R motions after binding, however, is not an easy task. We describe an approach that uses a reduced Hessian matrix to estimate the contributions due to translational and rotational degrees of freedom to entropy change upon molecular binding. The calculations use a harmonic model for the bound state but only include the T-R degrees of freedom. This approximation significantly speeds up entropy calculations because only 6 x 6 matrices need to be treated, which makes it easier to be used in computer-aided drug design for studying many ligands. The methodological connection with other methods is discussed as well. We tested this approximation by applying it to study the binding of ATP, peptide inhibitor (PKI), and several bound water molecules to protein kinase A (PKA). These ligands span a wide range in size. The model gave reasonable estimates of the residual T-R entropy of bound ligands or water molecules. The residual T-R entropy demonstrated a wide range of values, e.g., 4 to 16 cal/K.mol for the bound water molecules of PKA.     

The effects of wind and thermal radiation on thermal responses during rest and exercise in a cold environment

1. 1. The purpose of this study was to investigate the effects of thermal radiation and wind on thermal responses at rest and during exercise in a cold environment.

2. 2. The experimental conditions were radiation and wind (R + W), no radiation and wind (W), radiation and no wind (R), no radiation and no wind (C).

3. 3. The air temperature was −5°C. Thermal radiation was 360 W/m². Air velocities were 0.76, 1.73 and 2.8 m/s. Rectal and skin temperatures, heart rate and oxygen consumption were recorded. Thermal and comfort sensations were questioned.

4. 4. There are no significant effects of thermal radiation and wind on the physiological responses except the mean skin temperature. There are significant effects on the mean skin temperature (P < 0.01) and thermal sensation (P < 0.05).

Non-invasive microelectrode ion flux measurements to study adaptive responses of microorganisms to the environment

The regulation of membrane-transport activity is crucial for intracellular pH homeostasis, maintenance of cell osmotic potential, nutrient acquisition, signalling, and adaptation of bacterial cells. The non-invasive microelectrode ion flux estimation (MIFE) technique is a powerful tool for kinetic studies of membrane-transport processes across cellular membranes. Since 2001, when this technique was first applied to the study of membrane-transport processes in bacterial cells (J Microbiol Methods 46, 119-129), a large amount of information has been accumulated. This review summarizes some of these findings and discusses the advantages and applicability of this technique in studying bacterial adaptive responses to adverse environmental conditions. First, various methodological aspects of the application of this novel technique in microbiology are discussed. Then, several practical examples ('case studies') are described. The latter include changes in membrane-transport activity in response to various stresses (acidic, osmotic, and temperature stresses) as well as flux changes as a function of bacterial growth stage and nutrient availability. It is shown that non-invasive ion flux measurements may provide a significant conceptual advance in our understanding of adaptive responses in bacteria, fungi and biofilms to a variety of environmental conditions. The technique can also be used for the rapid assessment of food-processing treatments aimed at reducing bacterial contamination of food and for the development of strategies to assess the resistance of organisms to antimicrobial agents.     

Epigenetic regulation of adaptive responses of forest tree species to the environment

Epigenetic variation is likely to contribute to the phenotypic plasticity and adaptative capacity of plant species, and may be especially important for long‐lived organisms with complex life cycles, including forest trees. Diverse environmental stresses and hybridization/polyploidization events can create reversible heritable epigenetic marks that can be transmitted to subsequent generations as a form of molecular “memory”. Epigenetic changes might also contribute to the ability of plants to colonize or persist in variable environments. In this review, we provide an overview of recent data on epigenetic mechanisms involved in developmental processes and responses to environmental cues in plant, with a focus on forest tree species. We consider the possible role of forest tree epigenetics as a new source of adaptive traits in plant breeding, biotechnology, and ecosystem conservation under rapid climate change.     

The stress and metabolic responses of juvenile Atlantic cod Gadus morhua L. to an acute thermal challenge

Survival, oxygen consumption (     ), total plasma cortisol and glucose levels and gill heat-shock protein 70 (hsp70) expression were measured in 10 and 50 g juvenile Atlantic cod Gadus morhua during an acute temperature increase (2° C h⁻¹) to their critical thermal maximum. Ninety three per cent of the fish in both size classes survived to 24° C; however, mortality was 100% within 15 min of reaching this temperature. The     for both size classes increased significantly with temperature, reaching peak values at 22° C that were c. 2·8-fold those of control (10° C) fish. Resting plasma cortisol and glucose levels were lower in 10 g as compared to 50 g fish. Plasma glucose levels were highly variable in both size classes, and significant increases were only seen at >22° C for the 10 g fish. In contrast, plasma cortisol showed an exponential increase with temperature starting at 16° C in both size classes, and reached maximum levels at 22° C that were 19-fold (10 g fish) and 35-fold (50 g fish) higher than their respective control groups. Both the constitutive (73 kDa) and inducible (72 kDa) isoforms of hsp70 were detected in both size classes using the widely utilized mouse monoclonal antibody. Expression of these isoforms, however, did not change when Atlantic cod were exposed to elevated temperature, and the 72 kDa isoform was not detected using salmonid-specific antibodies. These results indicate that juvenile Atlantic cod are very sensitive to acute increases in water temperature. In addition, they (1) show that     and plasma cortisol, but not plasma glucose or gill hsp 70 levels, are sensitive indicators of thermal stress in Atlantic cod and (2) support previous reports that the upper critical temperature for this species is 16° C.     

Transcriptional analysis of normal human fibroblast responses to microgravity stress

To understand the molecular mechanism（s） of how spaceflight affects cellular signaling pathways, quiescent normal human WI-38 fibroblasts were flown on the STS-93 space shuttle mission. Subsequently, RNA samples from the spaceflown and ground-control cells were used to construct two cDNA libraries, which were then processed for suppression subtractive hybridization （SSH） to identify spaceflight-specific gene expression. The SSH data show that key genes related to oxidative stress, DNA repair, and fatty acid oxidation are activated by spaceflight, suggesting the induction of cellular oxidative stress. This is further substantiated by the up-regulation of neuregulin 1 and the calcium-binding protein calmodulin 2. Another obvious stress sign is that spaceflight evokes the Ras/mitogen-activated protein kinase and phosphatidylinositol-3 kinase signaling pathways, along with up-regulating several Gl-phase cell cycle traverse genes. Other genes showing upregulation of expression are involved in protein synthesis and pro-apoptosis, as well as pro-survival. Interactome analysis of functionally related genes shows that c-Myc is the ＂hub＂ for those genes showing significant changes. Hence, our results suggest that microgravity travel may impact changes in gene expression mostly associated with cellular stress signaling, directing cells to either apoptotic death or premature senescence.