Modularity,and the psychoevolutionary theory of emotion

It is unreasonable to assume that our pre-scientific emotion vocabulary embodies all and only those distinctions required for a scientific psychology of emotion. The psychoevolutionary approach to emotion yields an alternative classification of certain emotion phenomena. The new categories are based on a set of evolved adaptive responses, or affect-programs, which are found in all cultures. The triggering of these responses involves a modular system of stimulus appraisal, whose evoluations may conflict with those of higher-level cognitive processes. Whilst the structure of the adaptive responses is innate, the contents of the system which triggers them are largely learnt. The circuits subserving the adaptive responses are probably located in the limbic system. This theory of emotion is directly applicable only to a small sub-domain of the traditional realm of emotion. It can be used, however, to explain the grouping of various other phenomena under the heading of emotion, and to explain various characteristic failings of the pre-scientific conception of emotion.     

Subharmonics increase the auditory impact of female koala rejection calls

Although non‐linear phenomena are common in human and non‐human animal vocalisations, their functional relevance remains poorly understood. One theory posits that non‐linear phenomena generate unpredictability in vocalisations, which increases the auditory impact of vocal signals, and makes animals less likely to habituate to call repetition. Female koalas (Phascolarctos cinereus) produce vocal signals when they reject male copulation attempts that contain relatively high levels of non‐linear phenomena, and thus may function as attention grabbing vocal signals during the breeding season. To test this hypothesis, we used playback experiments: firstly, to determine whether female rejection calls induce heightened behavioural responses in free‐ranging male koalas during the breeding season, and secondly, to examine how the relative amount of non‐linear phenomena in rejection calls influences male behavioural response. The results show that male koalas look for longer towards speakers broadcasting playback sequences of male bellows followed by a series of female rejection calls than those broadcasting only male bellows. In addition, female rejection call sequences with more subharmonics, higher harmonics‐to‐noise ratios, and less biphonation produced the greatest male looking responses. Our findings support the hypothesis that female koala rejection calls function to grab male attention during the breeding season, and indicate that subharmonics are the main acoustic feature that increases the auditory impact of these vocal signals.     

Systems analysis of the renal function

A previous model of the renal function and compartmented whole body, which incorporated actions of antidiuretic hormone on urine flow and composition, is extended to include the influences of additional phenomena, many exogenous to the kidney. The phenomena incorporated were selected by orderly trial from among those mechanisms suggested in the literature and found by operation of the model to be important for adequately representing renal responses to various stresses. Specifically, these phenomena are: the intrinsic-osmotic effect of water; details of the body's antidiuretic hormone cycle; gastrointestinal exchanges; changes in glomerular filtration caused by alteration in blood volume and pressure; and resistance to flow across kidney tubular walls. Most of these phenomena involve non-steady-state, irreversible processes.The modeled renal function was found not to be sensitive to certain mechanisms sometimes associated with its operation. The most important is volume sensing, whereby extracellular volume changes are postulated to impose control on antidiuretic hormone production through stretch receptors in the circulatory system or through other volume sensors. Model investigations show that blood volume changes that alter blood pressure during stress can operate to affect kidney tubular-fluid flow in a manner which, when combined with other modeled kidney processes, yields correct urinary and other responses. No additional control on the antidiuretic hormone cycle through special volume receptors is required.The stresses to which the present model was exposed and responds correctly are: water loading through ingestion; hypertonic saline infusion; hypertonic urea solution ingestion; antidiuretic hormone dysfunction, as in diabetes insipidus; controlled rehydration after dehydration; and two combined stresses—hypertonic saline solution ingestion followed by water ingestion and the converse experiment. Most of these stresses involve transients in which the body becomes far removed from steady state. Different aspects of the total renal function, depending upon the specific stress, become more or less important in aiding the body to return to its original state.     

Postjunctional Origin of the indirect-like sympathomimetic effect of metanephrine and normetanephrine on blood pressure

The effects of metanephrine and normetanephrine have been compared with those from equiactive doses of the origin compounds, adrenaline and noradrenaline, on the pressor responses in rat, in order to determine whether their effects are owed, at least partially, to a releasing presynaptic action of the catecholamines in normal animals as well as those pretreated with reserpine, guanethidine and 6-OH-dopamine. Their effects have likewise been studied in isolated perfused renal arteries both in normal and reserpinized rats. None of the adrenolytic agent used were able either to reduce the duration of the hypertensive response or to accelerate tachyphylaxis. Identical results were obtained in renal artery preparations. It is thus concluded that the catecholamines stored in presynaptic endings are not involved in the observed phenomena and it is suggested that they might depend on the high doses required to produce effects equiactive to those of the origin substances.     

The use of 'altitude' in ecological research

Altitudinal gradients are among the most powerful 'natural experiments' for testing ecological and evolutionary responses of biota to geophysical influences, such as low temperature. However, there are two categories of environmental changes with altitude: those physically tied to meters above sea level, such as atmospheric pressure, temperature and clear-sky turbidity; and those that are not generally altitude specific, such as moisture, hours of sunshine, wind, season length, geology and even human land use. The confounding of the first category by the latter has introduced confusion in the scientific literature on altitude phenomena.     

Mathematical modelling of residue allelopathy: the effects of intrinsic and extrinsic factors

The mechanistic model of residue allelopathy that was constructed before only simulates allelopathic phenomena caused by decaying plant residues and does not include factors controlling expression of such phenomena. As both intrinsic and extrinsic factors are affecting the potential of residue allelopathy, the model has been developed further to include these factors. The concept of a constant for residue-allelopathic potential, functions for effects of temperature, water, and their combination on allelochemical concentrations were added to the model. As a result, the improved residue model is able to examine the responses to these phenomena under a wide variety of conditions. Several sets of published experimental data were compared with prediction from the model, and a good agreement has been achieved. Its significance in helping better understanding of residue allelopathy is discussed.     

The highly interrelated GHRH,p53, and Hsp90 universe

p53 universe is composed of a complex regulatory network, destined to counteract multifarious challenges threatening cell survival. Imbalance in those responses may result in human disease associated with inevitable consequences. The present work delivers our view of the corresponding phenomena, by involving the endothelium defender in meticulously orchestrated events against inflammatory stimuli. Immersing into the great depths of p53 cosmos may lead to promising therapies against devastating disorders, including acute respiratory distress syndrome.     

Modelling spatio-temporal interactions within the cell

Biological phenomena at the cellular level can be represented by various types of mathematical formulations. Such representations allow us to carry out numerical simulations that provide mechanistic insights into complex behaviours of biological systems and also generate hypotheses that can be experimentally tested. Currently, we are particularly interested in spatio-temporal representations of dynamic cellular phenomena and how such models can be used to understand biological specificity in functional responses. This review describes the capability and limitations of the approaches used to study spatio-temporal dynamics of cell signalling components.     

The stomach's link to the brain

Thirty years before Beaumont's publication of his observations of Alexis St. Martin, Pierre Jean Georges Cabanis, a brilliant but now little-known French physiologist, reported clinical data on digestive disturbances that accompany emotional upset. With extraordinary prescience he distinguished emotional states associated with the suppression of digestion from those that were accompanied by accelerated gastric secretory and motor function. However, Beaumont was the first to document the inhibitory effects on digestion by direct observation of the stomach. Later, others documented the excitatory effects, provided further detail concerning emotional states, and began to identify neuronal pathways and humoral mechanisms responsible for the phenomena. The integrative mechanisms in the brain that link life experience to gastric responses have come under study recently; the process has turned out to be immensely complex. Several neurotransmitters have been identified that subserve the facilitatory and inhibitory mechanisms converging on the efferent neurons that ultimately elicit patterns of visceral and general behavior. However, investigations of cognitive and emotional responses to stressful experiences have been largely neglected in humans. Although sophisticated methods and instruments exist that record in a noninvasive fashion a whole spectrum of gastric behavior, such studies are now out of fashion. To fully explore the stomach's link to the brain, research on the entire human organism must be revived.     

The conversion of variance and the evolutionary potential of restricted recombination

Genetic recombination is usually considered to facilitate adaptive evolution. However, recombination prevents the reliable cotransmission of interacting gene combinations and can disrupt complexes of coadapted genes. If interactions between genes have important fitness effects, restricted recombination may lead to evolutionary responses that are different from those predicted from a purely additive model and could even aid adaptation. Theory and data have demonstrated that phenomena that limit the effectiveness of recombination via increasing homozygosity, such as inbreeding and population subdivision and bottlenecks, can temporarily increase the additive genetic variance available to these populations. This effect has been attributed to the conversion of nonadditive to additive genetic variance. Analogously, phenomena such as chromosomal inversions and apomictic parthenogenesis that physically restrict recombination in part or all of the genome may also result in a release of additive variance. Here, we review and synthesize literature concerning the evolutionary potential of populations with effectively or physically restricted recombination. Our goal is to emphasize the common theme of increased short-term access to additive genetic variance in all of these situations and to motivate research directed towards a more complete characterization of the relevance of the conversion of variance to the evolutionary process.     

Fusicoccin stimulates the production of H2O2 in sycamore cell cultures and induces alternative respiration and cytochrome c leakage from mitochondria

Fusicoccin (FC) is a well known toxin acting as a 14-3-3 protein-mediated activator of the plasma membrane H⁺-ATPase and it has been widely used to study the regulatory mechanism and the physiological role of this enzyme's activity. Recently, FC has been shown to induce other responses similar to those occurring under a stress condition, perhaps not strictly dependent on the activation of proton extrusion. In this paper we report that in cultured sycamore ( Acer pseudoplatanus L.) cells FC induces H₂O₂ overproduction as well as other novel, presumably related responses, such as the activation of the alternative oxidase and the leakage of cytochrome c from the mitochondria, accompanied by a decrease of the cytochrome pathway capacity. The relationship between H₂O₂ production and other phenomena has also been studied by means of exogenously added H₂O₂.     

Dynamics of Cellular Responses to Radiation

Understanding the consequences of exposure to low dose ionizing radiation is an important public health concern. While the risk of low dose radiation has been estimated by extrapolation from data at higher doses according to the linear non-threshold model, it has become clear that cellular responses can be very different at low compared to high radiation doses. Important phenomena in this respect include radioadaptive responses as well as low-dose hyper-radiosensitivity (HRS) and increased radioresistance (IRR). With radioadaptive responses, low dose exposure can protect against subsequent challenges, and two mechanisms have been suggested: an intracellular mechanism, inducing cellular changes as a result of the priming radiation, and induction of a protected state by inter-cellular communication. We use mathematical models to examine the effect of these mechanisms on cellular responses to low dose radiation. We find that the intracellular mechanism can account for the occurrence of radioadaptive responses. Interestingly, the same mechanism can also explain the existence of the HRS and IRR phenomena, and successfully describe experimentally observed dose-response relationships for a variety of cell types. This indicates that different, seemingly unrelated, low dose phenomena might be connected and driven by common core processes. With respect to the inter-cellular communication mechanism, we find that it can also account for the occurrence of radioadaptive responses, indicating redundancy in this respect. The model, however, also suggests that the communication mechanism can be vital for the long term survival of cell populations that are continuously exposed to relatively low levels of radiation, which cannot be achieved with the intracellular mechanism in our model. Experimental tests to address our model predictions are proposed.     

Confronting the Naturalness of Disaster in the Pacific

ABSTRACT

This introduction sets out some of the key themes addressed by the papers in the special issue on ‘Confronting the Naturalness of Disaster in the Pacific’. Disasters are now widely understood not as ‘natural’ phenomena but as events or processes that unfold at the intersection between natural or artificial hazards and human populations. We review some of the effects of the naturalisation of disaster before turning to the ways in which Pacific disasters are defined through government, media and public discourses. These discourses feature their own distinctive accounts of possible forms of agency in the context of disaster, and draw on markedly different frames of reference in attributing cause and blame. Similarly, contrasting temporalities and spatialities are invoked in addressing disasters as bounded phenomena. We conclude with reflections on the nature of responses to disaster in the Pacific in the context of increasingly unstable cultural, economic and environmental grounds for action induced by global climate change     

Hypertension: the sodium connection

It appears from epidemiologic, population, and individual studies that sodium is capable of raising blood pressure and its attendant cardiovascular complications in susceptible individuals. Potassium loss occurs with sodium loading and may modulate the blood pressure responses to sodium. Populations known to be at greater risk for the development of hypertension and its cardiovascular sequelae, such as blacks, older individuals, and those over the age of 40 years are also known to be less efficient in handling sodium. Furthermore, they are more apt to be sodium-sensitive than -resistant. The phenomena of sensitivity and resistance, demonstrable in both normotensive and hypertensive individuals, can be identified by rapid sodium and volume loading and depletion as well as by modest reduction in dietary sodium intake. Finally, preliminary evidence suggests that sodium sensitivity may be predictable by genetic markers as well as by demographic characteristics.     

Sensitivity to catecholamines and histamine in the trained and in the untrained human organism and sensitivity changes during digestion.

Blood pressure and heart rate responses elicited by norepinephrine, epinephrine and histamine were compared before and after duodenal acidification in 27 trained and untrained young healthy men. Before acidification trained subjects showed a lower sensitivity to norepinephrine and histamine and a slightly lower one to epinephrine. In order to explain these phenomena physical training was supposed to affect alpha, respectively beta adrenergic responsivity in a dissimilar manner. This suggestion was confirmed by the isoproterenol studies, too. Duodenal acidification decreased the catecholamine-induced pressor responses. Depressor responses to histamine did not change in the untrained subjects, whereas they increased in the trained group. Thus, during digestion the histamine-induced depressor responses of trained subjects tended to approach that of untrained people.     

The control of stomata by water balance

It is clear that stomata play a critical role in regulating water loss from terrestrial vegetation. What is not clear is how this regulation is achieved. Stomata appear to respond to perturbations of many aspects of the soil-plant-atmosphere hydraulic continuum, but there is little agreement regarding the mechanism (or mechanisms) by which stomata sense such perturbations. This review discusses feedback and feedforward mechanisms by which hydraulic perturbations are putatively transduced into stomatal movements, in relation to generic empirical features of those responses. It is argued that a metabolically mediated feedback response of stomatal guard cells to the water status in their immediate vicinity ('hydro-active local feedback') remains the best explanation for many well-known features of hydraulically related stomatal behaviour, such as transient 'wrong-way' responses and the equivalence of hydraulic supply and demand as stomatal effectors. Furthermore, many curious phenomena that appear inconsistent with feedback, such as 'apparent feedforward' humidity responses and 'isohydric' behaviour (water potential homeostasis), are in fact expected to emerge from the juxtaposition of hydro-active local feedback and the well-known hysteretic and threshold-like effect of water potential on xylem hydraulic resistance.     

Global changes explain the long-term demographic trend of the Eurasian common lizard (Squamata: Lacertidae)

The demographic trend of a species depends on the dynamics of its local populations, which can be compromised by local or by global phenomena. However, the relevance of local and global phenomena has rarely been investigated simultaneously. Here, we tested whether local phenomena compromised a species’ demographic trend using the Eurasian common lizard Zootoca vivipara, the terrestrial reptile exhibiting the widest geographic distribution, as a model species. We analyzed the species’ ancient demographic trend using genetic data from its 6 allopatric genetic clades and tested whether its demographic trend mainly depended on single clades or on global phenomena. Zootoca vivipara’s effective population size increased since 2.3 million years ago and started to increase steeply and continuously from 0.531 million years ago. Population growth rate exhibited 2 maxima, both occurring during global climatic changes and important vegetation changes on the northern hemisphere. Effective population size and growth rate were negatively correlated with global surface temperatures, in line with global parameters driving long-term demographic trends. Zootoca vivipara’s ancient demography was neither driven by a single clade, nor by the 2 clades that colonized huge geographic areas after the last glaciation. The low importance of local phenomena, suggests that the experimentally demonstrated high sensitivity of this species to short-term ecological changes is a response in order to cope with short-term and local changes. This suggests that what affected its long-term demographic trend the most, were not these local changes/responses, but rather the important and prolonged global climatic changes and important vegetation changes on the northern hemisphere, including the opening up of the forest by humans.     

The effects of electrical stimulation of posterior hypothalamus on activity of the nucleus pontis oralis' neurons

The nucleus pontis oralis' neurons were responsive to electrical stimulation of posterior hypothalamus. PS-on neurons showed an inhibitory response, and PS-off cells demonstrated an excitatory response. Neurons that discharged in association with phasic paradoxical sleep phenomena were found to have both the excitatory and the inhibitory responses. Evoked responses changed across sleep-waking cycle. The findings suggest that posterior hypothalamus is involved in the control of paradoxical sleep generation mechanisms located in the nucleus pontis oralis.