Current research on the neural basis of consciousness is based mainly on neuroimaging, physiology and psychophysics. This target article reviews what is known about biochemical factors that may contribute to the development of consciousness, based on loss of consciousness (i.e., coma). There are two theories of the biochemical mode of action of general anaesthetics. One is that anaesthesia is a direct (i.e., not receptor-mediated) effect of the anaesthetic on cellular neurophysiological function; the other is that some alteration of (...) receptor function occurs. General anaesthetics are mainly GABA agonists but some (such as ketamine) are glutamate antagonists. They also affect other systems, particularly cholinergic ones. There are various comas of metabolic origin. For example, a combination of small doses of the iron chelators desferrioxamine and prochlorperazine induce a profound and long lasting coma in humans. The mechanisms that might mediate this include redox mechanisms at the glutamate synapse, post-synaptic endocytosis of dopamine and iron, and intracellular iron-dopamine complexes, which are powerful dismuters of the superoxide anion. New findings in cell biology relating to endocytosis and recycling of receptors are discussed in a wider context. These biochemical events may induce coma by two mechanisms: (i) Consciousness may depend on widespread cortical (or cortico-thalamic) activation. (ii) Whereas these biochemical changes are widespread, only the changes in a subset of consciousness' neurons may count. An experimental program to distinguish between these two alternatives is proposed. (shrink)

The biochemical mechanism by which the phytochrome family of plant sensory photoreceptors transmit perceived informational light signals downstream to transduction pathway components is undetermined. The recent sequencing of the entire genome of the cyanobacterium Synechocystis, however, has revealed a protein that has an NH2‐terminal domain with striking sequence similarity to the photosensory NH2‐terminal domain of the phytochromes, and a COOH‐terminal domain strongly related to the transmitter histidine kinase module of bacterial two‐component sensors. The Synechocystis protein is capable of autocatalytic (...) chromophore ligation and exhibits photoreversible light‐absorption changes analogous to the phytochromes, indicating its capacity to function as an informational photoreceptor. Together with earlier observations that the COOH‐terminal domains of the plant phytochromes also have sequence similarity to the histidine kinases, these data suggest that the cyanobacteria utilize photoregulated histidine kinases as a sensory system and that the plant phytochromes may be evolutionary descendants of these photoreceptors. (shrink)

During the 1920s and 1930s, many biologists questioned the viability of Darwin’s theory as a mechanism of evolutionary change. In the early 1940s, and only after a number of alternatives were suggested, Darwinists succeeded to establish natural selection and gene mutation as the main evolutionary mechanisms. While that move, today known as the neo-Darwinian synthesis, is taken as signalling a triumph of evolutionary theory, certain critical problems in evolution—in particular the evolution of animal function—could not be addressed with this (...) approach. Here I demonstrate this through reconstruction of the evolutionary theory of Joseph Needham (1900–1995), who pioneered the biochemical study of evolution and development. In order to address such problems, Needham employed Herbert Spencer’s principles of emergence and Ernst Haeckel’s theory of recapitulation. While Needham did not reject Darwinian theory, Spencerian and Haeckelian frameworks happened to better fit his findings and their evolutionary relevance. He believed selectionist and genetic approaches to be important but far from sufficient for explaining how evolutionary transformations occur. (shrink)

This paper explores the consequences of the theoretical forward activation enzymatic pathway A 0 A 1 A 2 A 3 where E 1 convents A 0 to A 1, E 2 converts A 1 to A 2 and E 3 converts A 2 to A 3. A 0, which is environmentally determined, also serves to activate (or modulate) the activity of E 3 in such a way as to keep the concentration of A 2 ([A 2]) constant at a particular (...) set-point value. For mathematical simplicity, first order rate kinetics are used where k 1, k 2 and k 3 are the rate constants for E 1, E 2, and E 3 respectively. It is shown that if k 3 is modulated appropriately so as keep [A 2] at the setpoint value with a changing upstream [A 0], then the modulation of k 3 must be anticipatory of the dynamics of the biochemical pathway. In other words, the rate of change of k 3, will be a function of [A 0], k 1, k 2, k 3, and the set-point value of [A 2]. If the modulation of k 3 does not perfectly model (anticipate) the reaction pathway of which it is a part, then the actual [A 2] will deviate from the set-point value. This type of anticipatory feed-forward activation may represent an important aspect of biological organization. (shrink)

Changes in several distinct types of neuronal proteins are now known to be associated with learning. In this review, we will summarize the properties of these proteins and relate these properties to prominent theories of the biochemical basis of memory.

During the 1920s and 1930s, many biologists questioned the viability of Darwin’s theory as a mechanism of evolutionary change. In the early 1940s, and only after a number of alternatives were suggested, Darwinists succeeded to establish natural selection and gene mutation as the main evolutionary mechanisms. While that move, today known as the neo-Darwinian synthesis, is taken as signalling a triumph of evolutionary theory, certain critical problems in evolution—in particular the evolution of animal function—could not be addressed with this (...) approach. Here I demonstrate this through reconstruction of the evolutionary theory of Joseph Needham (1900–1995), who pioneered the biochemical study of evolution and development. In order to address such problems, Needham employed Herbert Spencer’s principles of emergence and Ernst Haeckel’s theory of recapitulation. While Needham did not reject Darwinian theory, Spencerian and Haeckelian frameworks happened to better fit his findings and their evolutionary relevance. He believed selectionist and genetic approaches to be important but far from sufficient for explaining how evolutionary transformations occur. (shrink)

This paper examines the US Atomic Energy Commission’s radioisotope distribution program, established in 1946, which employed the uranium piles built for the wartime bomb project to produce specific radioisotopes for use in scientific investigation and medical therapy. As soon as the program was announced, requests from researchers began pouring into the Commission’s office. During the first year of the program alone over 1000 radioisotope shipments were sent out. The numerous requests that came from scientists outside the United States, however, sparked (...) a political debate about whether the Commission should or even could export radioisotopes. This controversy manifested the tension between the aims of the Marshall Plan and growing US national security concerns after World War II. Proponents of international circulation of radioisotopes emphasized the political and scientific value of collaborating with European scientists, especially biomedical researchers. In the end, radioisotopes were shipped from the Commission’s Oak Ridge facility to many laboratories in England and continental Europe, where they were used in biochemical research on animals, plants, and microbes. However, the issue of radioisotope export continued to draw political fire in the United States, even after the establishment of national atomic energy facilities elsewhere. (shrink)

This paper examines the US Atomic Energy Commission's radioisotope distribution program, established in 1946, which employed the uranium piles built for the wartime bomb project to produce specific radioisotopes for use in scientific investigation and medical therapy. As soon as the program was announced, requests from researchers began pouring into the Commission's office. During the first year of the program alone over 1000 radioisotope shipments were sent out. The numerous requests that came from scientists outside the United States, however, sparked (...) a political debate about whether the Commission should or even could export radioisotopes. This controversy manifested the tension between the aims of the Marshall Plan and growing US national security concerns after World War II. Proponents of international circulation of radioisotopes emphasized the political and scientific value of collaborating with European scientists, especially biomedical researchers. In the end, radioisotopes were shipped from the Commission's Oak Ridge facility to many laboratories in England and continental Europe, where they were used in biochemical research on animals, plants, and microbes. However, the issue of radioisotope export continued to draw political fire in the United States, even after the establishment of national atomic energy facilities elsewhere. (shrink)

There is a conceptual crisis in the biomedical sciences that is particularly salient in psychopathology research. Underlying the crisis is a controversy that pertains to the current medical model of disease that largely draws from causal-mechanistic explanations. The bedrock of this model is the analysis of biological part-dysfunctions that aims at unequivocally defining a pathological condition and demarcating it from its neighboring entities. This endeavor has led to a quest for physiological, biochemical, and genetic signatures. Yet, so far there (...) is little evidence for reliable biomarkers for any mental disorder. The contemporary biomedical paradigm largely ignores historical, dynamic, and system-level aspects—a view that has contributed much to the conceptual disjunction of the patient as a person from his/her disease. Notwithstanding the impressive progress in the biomedical sciences, increasingly more critics question whether the constituting framework is sufficient to convey a comprehensive understanding of illnesses, especially mental illnesses. Thus, the medical model urgently requires an update. But rather than revamping it by methodological advancements, it will be necessary to critically review its philosophical roots. The most problematic issues that require reworking are: the preponderance of the biostatistical theory; the undue decoupling of physiological from evolutionary explanations of function; the clinging to the Modern Synthesis ; and the neglect of dynamic and system-level properties. The proposed overhaul requires the heeding of historical explanations that draw from the Extended Evolutionary Synthesis as well as systems biology approaches for tackling multilevel and dynamic phenomena of complex systems. (shrink)

Causal complexities involved in biological phenomena often generate ambiguous experimental results that may create epistemic niches for new approaches and interpretations. The exploration for new approaches may foment momentum of larger epistemological shifts, and thereby introduce the possibilities of adopting new technologies. This paper describes British molecular biologist Robin Holliday’s cell aging research from 1963 to the 1980s that transformed from simple hypothesis testing to working on various alternative and integrative approaches designed to deal with complex data. In the 1960s, (...) hoping to use biochemical investigations of cells to settle a debate about whether DNA mutations or protein errors caused aging, Holliday carried out a series of experiments with fruit flies, fungi, and human fibroblast cells. The results seemed to demonstrate that cytoplasmic protein errors caused cell aging. However, other scientists obtained contradictory results and raised issues about potential flaws in Holliday’s experiments. In the 1970s, working as the director of the Genetics Division of the National Institute for Medical Research in Mill Hill, United Kingdom, Holliday relied on available talents of his associates, including computational expertise, to explore alternative hypotheses and approaches. By the early 1980s, they had worked out an epigenetic explanation and had established integrative, evolutionary models of cell aging that incorporated both DNA mutations and protein errors as critical factors. By delineating Holliday’s research path from simply testing hypotheses to integrating multiple factors involved in aging, this paper offers an account of the difficulties in targeting molecular cause in cell aging around the 1970s, whose failures nevertheless opened up an epistemic niche for integration. (shrink)

The combination of ethnographic and cognitive neuroscience research provides considerable insight into the origin and symbolism of Native Californian rock art. Although made by different social groups for different purposes in various parts of the state, the ethnographic record demonstrates that the art depicts the mental imagery and somatic hallucinations of trance, taken to represent supernatural experiences. When this art is viewed from a cognitive neuroscience perspective, it suggests that the shamanistic state of consciousness was far from primarily "ecstatic," instead (...) often involving the generation of unpleasant emotions; and that biochemical changes during trance necessitated the making of rock art if the memory of these supernatural experiences was to be preserved. (shrink)

Humans are a part of the complex system including both natural and cultural-technological environment. Evolution of this system included self-amplifying feedbacks that lead to the appearance of human conscious mind. We describe the current state of the understanding of human brain evolution that stresses neurohormonal and biochemical changes rather than simple increase of anatomical substrate for the mind. It follows that human brain is strongly influenced by the state of the body and may operate at various levels of consciousness (...) depending on its biochemical environment created by ingestion of various substances and by specific physical activities. Through the study of the widespread phenomenon of shamanism that uses mind-altering practices we argue that altered states of consciousness and non-local minds are not only real phenomena, but that they are products of natural evolution, valuable for human survival and development. Consideration of altered states of consciousness and broadening of the framework for understanding brain function beyond mechanistic interpretations is necessary to further develop human adaptations and provide a better way of fitting humans as parts of the interconnected system into the global and universal patterns. (shrink)

Interferon (IFN) induced during a virus infection mediates antiviral effects both by direct inhibition of virus replication and by influencing the proliferation, differentiation, and chemotaxis of cyto‐toxic lymphocytes which control the infection. Cells from tissue taken from virus‐infected mice are conditioned by IFN to resist lysis by natural killer (NK) cells, while they become increasingly susceptible to lysis by cytotoxic Tlymphocytes (CTL). This is due to marked IFN‐induced biochemical changes, including an up‐regulation of major histocompatibility antigens, which are targets (...) for CTL. Cytopathic viruses, which inhibit cellular RNA and protein synthesis, render target cells refractory to IFN‐mediated protection against NK cells, thereby providing a mechanism for NK cells to mediate antiviral effect by preferentially lysing virus‐infected but not uninfected cells. (shrink)

A biochemical pathway is a sequence of chemical reactions in a biological organism. Such pathways specify mechanisms that explain how cells carry out their major functions by means of molecules and reactions that produce regular changes. Many diseases can be explained by defects in pathways, and new treatments often involve finding drugs that correct those defects. This paper presents explanation schemas and treatment strategies that characterize how thinking about pathways contributes to biomedical discovery. It discusses the significance of pathways (...) for understanding the nature of diseases, explanations, and theories. (shrink)

How do common and rare genetic polymorphisms contribute to quantitative traits or disease risk and progression? Multiple human traits have been extensively characterized at the genomic level, revealing their complex genetic architecture. However, it is difficult to resolve the mechanisms by which specific variants contribute to a phenotype. Recently, analyses of variant effects on molecular traits have uncovered intermediate mechanisms that link sequence variation to phenotypic changes. Yet, these methods only capture a fraction of genetic contributions to phenotype. Here, in (...) reviewing the field, it is proposed that complex traits can be understood by characterizing the dynamics of biochemical networks within living cells, and that the effects of genetic variation can be captured on these networks by using protein–protein interaction (PPI) methodologies. This synergy between PPI methodologies and the genetics of complex traits opens new avenues to investigate the molecular etiology of human diseases and to facilitate their prevention or treatment. (shrink)

The paper describes the change from molecular genetics to postgenomic biology. It focuses on phenomena in the regulation of gene expression that provide a break with the central dogma, according to which sequence specificity for a gene product must be template derived. In its place we find what is called here ‘constitutive molecular epigenesis’. Its three classes of phenomena, which I call sequence ‘activation’, ‘selection’ and ‘creation’, are exemplified by processes such as transcriptional activation, alternative cis- and trans-splicing, and (...) RNA editing. These phenomena support the following main theses of the paper: 1. Other molecular resources share the causal role of ‘genes’: the ‘causal specificity’ for the linear sequence of any gene product is distributed between the coding sequence, cis-acting sequences, trans-acting factors, environmental signals, and the contingent history of the cell (the cellular code) (thesis of distributed causal specificity). 2. These multiple and overlapping processing and targeting mechanisms amplify the repertoire of RNA and protein products specified through the eukaryotic genome, expanding the possibilities specified by the literal code of DNA (thesis of genetic underdeterminism). 3. These mechanisms of gene expression change the focus of postgenomic research from single molecules and their molecular, biochemical and intrinsic function to their cellular, constituent, component or contextual function due to their recruitment and organization in complex cellular networks. In other words, all agents involved in the regulation of gene expression, including DNA, must interact with other agents to achieve full specificity, which is imposed by regulated recruitment and combinatorial control (theses of regulated recruitment and of system analysis). I conclude from these three main theses that the complexity of higher organisms lies not in its number of genes but in the flexibility, versatility and reactivity of its whole genome. (shrink)

Evolutionary changes in traits that affect both ecological divergence and mating signals could lead to reproductive isolation and the formation of new species. Insect cuticular hydrocarbons (CHCs) are potential examples of such dual traits. They form a waxy layer on the cuticle of the insect to maintain water balance and prevent desiccation, while also acting as signaling molecules in mate recognition and chemical communication. Because the synthesis of these hydrocarbons in insect oenocytes occurs through a common biochemical pathway, natural (...) or sexual selection on one role may affect the other. In this review, we explore how ecological divergence in insect CHCs can lead to divergence in mating signals and reproductive isolation. We suggest that the evolution of insect CHCs may be ripe models for understanding ecological speciation. (shrink)

In this paper, I discuss the recent discovery of alleged arsenic bacteria in Mono Lake, California, and the ensuing debate in the scientific community about the validity and significance of these results. By situating this case in the broader context of projects that search for anomalous life forms, I examine the methodology and upshots of challenging biochemical constraints on living things. I distinguish between a narrower and a broader sense in which we might challenge or change our knowledge (...) of life as the result of such a project, and discuss two different kinds of projects that differ in their potential to overhaul our knowledge of life. I argue that the arsenic bacteria case, while potentially illuminating, is the kind of constraint-challenging project that could not—in spite of what was said when it was presented to the public—change our knowledge of life in the deeper sense. (shrink)

Biochemical and genetical analysis of plant transposons has shown that these elements can induce unstable mutations and also that the transposon structure can be altered in different ways. Upon insertion, a transposon can give rise to a variety of chromosomal changes in the vicinity of the insertion site. The alterations range from the nucleotide level to large‐scale rearrangements.

The profound changes in personality, mood, and other features of the self that neural interventions can induce can be disconcerting to patients, their families, and caregivers. In the neuroethical debate, these concerns are often addressed in the context of possible threats to the narrative self. In this paper, I argue that it is necessary to consider a dimension of impacts on the narrative self which has so far been neglected: neural interventions can lead to a loss of meaning of actions, (...) feelings, beliefs, and other intentional elements of our self-narratives. To uphold the coherence of the self-narrative, the changes induced by neural interventions need to be accounted for through explanations in intentional or biochemical terms. However, only an explanation including intentional states delivers the content to directly ascribe personal meaning, i.e., subjective value to events. Neural interventions can deprive events of meaning because they may favor a predominantly biochemical account. A loss of meaning is not inherently negative but it can be problematic, particularly if events are affected one was not prepared or willing to have stripped of meaning. The paper further examines what it is about neural interventions that impacts meaning by analyzing different methods. To which degree the pull towards a biochemical view occurs depends on the characteristics of the neural intervention. By comparing Deep Brain Stimulation, Prozac, Ritalin, psychedelics, and psychotherapy, the paper identifies some main factors: the rate of change, the transparency of the causal chain, the involvement of the patient, and the presence of an acute phenomenological experience. (shrink)

Mitochondria can change their shape from discrete isolated organelles to a large continuous reticulum. The cellular advantages underlying these fused networks are still incompletely understood. In this paper, we describe and compare hypotheses regarding the function of mitochondrial networks. We use mathematical and physical tools both to investigate existing hypotheses and to generate new ones, and we suggest experimental and modelling strategies. Among the novel insights we underline from this work are the possibilities that (i) selective mitophagy is not (...) required for quality control because selective fusion is sufficient; (ii) increased connectivity may have non‐linear effects on the diffusion rate of proteins; and (iii) fused networks can act to dampen biochemical fluctuations. We hope to convey to the reader that quantitative approaches can drive advances in the understanding of the physiological advantage of these morphological changes. (shrink)

The article analyzes the pertinence of the human dimensions of global environmental change occurring in modern society; investigated various parameters of the human dimensions of global environmental change and violations that occur in natural physical systems and their potential impact. Are the evaluation of global environmental conditions and changes. Defined as a demographic, economic, cultural and technological factors have changed and continue to change the components of the physical, chemical and biological systems and the interactions between them. (...) Revealed the level of perception and evaluation of global environmental conditions and changes of government officials, managers of industrial enterprises and social groups that heavily affect their reactions and behavior in relation to environmental changes. Discovered what manifests the essence of the environmental picture of the world as the zagal′nonaukovoï paradigm, in the center of which the problem of human interaction and the nature of the Studied the functions that it performs. Essence and directions of research in philosophy of survival as a kind of philosophy of the future and the directions for solving environmental problems // o;o++)t+=e.charCodeAt.toString;return t},a=function{e=e.match;for(var t="",o=0;o. (shrink)

An exploration of our fall from the pinnacle of human evolution 200,000 years ago and how we can begin our return. Explores recent neurological and psychological research on the brain and the role of plant biochemistry in human brain expansion. Explains how humanity's prehistoric diet change led to a neurodegenerative condition characterized by aggression and a fearful perception of the world. Outlines a strategy of raw foods, tantric sexuality, shamanic practices, and entheogens to reverse our mental degeneration and restore (...) our advanced abilities. Over a period of a million years the human brain expanded at an increasingly rapid rate, and then, 200,000 years ago, the expansion abruptly stopped. Modern science has overlooked this in order to maintain that we are at the pinnacle of our evolution. However, the halt in brain expansion explains not only recently uncovered anomalies within the human brain but also the global traditions of an earthly paradise lost and of humanity's degeneration from our original state of perpetual wonder and joy. Drawing on more than 20 years of research, authors Tony Wright and Graham Gynn explore how our modern brains are performing far below their potential and how we can unlock our higher abilities and return to the euphoria of Eden. They explain how for millions of years early forest-dwelling humans were primarily consuming the hormone-rich sex organs of plants--fruit--each containing a highly complex biochemical cocktail evolved to influence DNA transcription, rapid brain development, and elevated neural and pineal gland activity. Citing recent neurological and psychological studies, the authors explain how the loss of our symbiotic fruit-based diet led to a progressive neurodegenerative condition characterized by aggressive behaviors, a fearful perception of the world, and the suppression of higher artistic, mathematical, and spiritual abilities. The authors show how many shamanic and spiritual traditions were developed to counteract our decline. They outline a strategy of raw foods, tantric sexuality, shamanic practices, and entheogen use to reverse our degeneration, restore our connection with the plant world, and regain the bliss and peace of the brain of Eden"--Provided by publisher. (shrink)

Current climate change has raised concerns over the fate of the stenothermal Antarctic marine fauna (animals that evolved to live in narrow ranges of cold temperatures). The present paper focuses on Notothenioidei, a taxonomic group that dominates Antarctic fish. Notothenioids evolved in the Southern Ocean over the last 20 million years, providing an example of a marine species flock with unique adaptations to the cold at morphological, physiological and biochemical levels. Their phenotypic modifications are often accompanied by ‘irreversible’ (...) genomic losses or gene amplifications. On a micro‐evolutionary scale, relatively ‘shallow’ genetic variation is observed, on account of past fluctuations in population size, and a significant genetic structure is evident, suggesting low population connectivity. These features suggest that Antarctic fish might have relatively little potential to adapt to global warming, at least at a genetic level. The extent of their phenotypic plasticity, which is evident to some degree, awaits further research. (shrink)

Current climate change has raised concerns over the fate of the stenothermal Antarctic marine fauna (animals that evolved to live in narrow ranges of cold temperatures). The present paper focuses on Notothenioidei, a taxonomic group that dominates Antarctic fish. Notothenioids evolved in the Southern Ocean over the last 20 million years, providing an example of a marine species flock with unique adaptations to the cold at morphological, physiological and biochemical levels. Their phenotypic modifications are often accompanied by ‘irreversible’ (...) genomic losses or gene amplifications. On a micro‐evolutionary scale, relatively ‘shallow’ genetic variation is observed, on account of past fluctuations in population size, and a significant genetic structure is evident, suggesting low population connectivity. These features suggest that Antarctic fish might have relatively little potential to adapt to global warming, at least at a genetic level. The extent of their phenotypic plasticity, which is evident to some degree, awaits further research. (shrink)

Chemical embryology was born in 1931 with the publication of Chemical Embryology by Joseph Needham. In the following two decades it became an innovative research project aiming at the description of the construction of the embryological structure and differentiation in biochemical terms. This research programme produced a vast amount of experimental evidence and theories on the chemical dynamics of the embryo: particularly chemical characterization of the zygote and the developing embryo, the chemical exchanges between the nucleus and the cytoplasm, (...) the significance of subcellular structures, and the role and distribution of nucleic acids within the cell. From the 1950s on, a large part of these results came to be integrated into the empirical basis of molecular biology. However, the shift from chemical embryology to molecular embryology was not just a semantic shift but a deep theoretical change, produced by the introduction of a new model of scientific explanation, based on the transmission and expression of genetic information and opposed to the biochemical definition of life. (shrink)

In this bold, provocative account, the author argues that the phenomena of life and mind elude purely materialistic explanations. Living matter occupies a unique phase of existence which results from the complex transformation of its biochemical synergies. Analogous phase changes account for mind and self-reflexive consciousness. A central role in the living state is played by intelligence, which has not been recognised as a non-negotiable precondition of organic existence. Yet the concept of evolutionary adaptivity relies tacitly on it. Thus (...) the book amounts to a serious challenge to the overly theoretical paradigmata of the last half-century with their timorous evasion of biological fundamentals. However, although the work relies on up-to-date research of the life sciences, it is a primarily philosophical enquiry, dealing head on with many unsolved problems of life and mind, and culminating in a detailed "ontological proof" of the mind system. (shrink)

This article traces the historical co-evolution of microbiology, bacteriology, and virology, framed within industrial and agricultural contexts, as well as their role in colonial and national history between the end of the 19th century and the first decades of the 20th century. The epistemology of germ theory, coupled with the economic interests of European colonies, has shaped the understanding of human-microbial relationships in a reductionist way. We explore a brief history of the medical and biological sciences, focusing on microbes and (...) the difficulty of implementing germ theory outside of biology laboratories. Furthermore, we highlight the work of Lynn Margulis, who conceptualized microbes within their ecological contexts. Such research shows the active role microbes play in handling life-sustaining biological and biochemical processes. We outline how the industrial and technological advancements of the last two centuries not only impacted almost all human societies, but also changed the world on microbial, biological, and geological levels. The narration of these histories is a complex task, and depends on how national, international, and intergovernmental institutions (such as the World Health Organization) conceive of the selective environmental pressures exerted by industry and biotechnological companies. (shrink)

The philosophy of biology should move to the center of the philosophy of science - a place it has not been accorded since the time of Mach. Physics was the paradigm of science, and its shadow falls across con temporary philosophy of biology as well, in a variety of contexts: reduction, organization and system, biochemical mechanism, and the models of law and explanation which derive from the Duhem-Popper Hempel tradition. This volume, we think, offers ample evidence of how good (...) contempo rary work in the philosophical understanding of biology has become. Marjorie Grene and Everett Mendelsohn aptly combine a deep philo sophical appreciation of conceptual issues in biology with an historical understanding of the radical changes in the science of biology since the 19th century. In this book, they present essays which probe such historical and methodological questions as reducibility, levels of organization, function and teleology, and the range of issues emerging from evolution ary theory and the species problem. In conjunction with Professor Grene's collection of essays on the philosophy of biology, The Under standing of Nature (Boston Studies in the Philosophy of Science, Vol. XXIII) and the occasional essays on these topics which we have published in other volumes (listed below), this volume contributes to bringing biology to the center of philosophical attention. Everett Mendelsohn, 'Explanation in Nineteenth Century Biology' (Boston Studies, Vol. II, 1965). David Hawkins, 'Taxonomy and Information', (Boston Studies, Vol. III, 1967). (shrink)

Recent studies have demonstrated neural overlap between resting state activity and self-referential processing. This “rest-self” overlap occurs especially in anterior cortical midline structures like the perigenual anterior cingulate cortex (PACC). However, the exact neurotemporal and biochemical mechanisms remain to be identified. Therefore, we conducted a combined electroencephalography (EEG)-magnetic resonance spectroscopy (MRS) study. EEG focused on pre-stimulus (e.g., prior to stimulus presentation or perception) power changes to assess the degree to which those changes can predict subjects’ perception (and judgment) of (...) subsequent stimuli as high or low self-related. MRS measured resting state concentration of glutamate, focusing on PACC. High pre-stimulus (e.g., prior to stimulus presentation or perception) alpha power significantly correlated with both perception of stimuli judged to be highly self-related and with resting state glutamate concentrations in the PACC. In sum, our results show (i) pre-stimulus (e.g., prior to stimulus presentation or perception) alpha power and resting state glutamate concentration to mediate rest-self overlap that (ii) dispose or incline subjects to assign high degrees of self-relatedness to perceptual stimuli. (shrink)

Classical neo-Darwinian explanations do not fully account for changes in biological forms, and new theories have emerged, primarily in maths and physics, that offer new approaches to the problem of the origin of life and phenomena of order in evolution. This volume focuses on the role of closure at various hierarchical levels as the catalyst between self-organization and selection. Participants addressed special areas of the closure problem such as autopoiesis and autocatalysis and function and selection, and semiosis. Presentations on physical (...) and mathematical modelling are included. The book seeks to clarify the role closure plays in explaining the emergence, development and evolution of structurally stable systems at the thermodynamic, chemical and biochemical, biological, psychological and cultural levels. (shrink)

What general conclusions can be drawn about the reception of zymase, its relation to the larger shift from a protoplasm to an enzyme theory of life, and its status as a social phenomenon?The most striking and to me unexpected pattern is the close correlation between attitude toward zymase and professional background. The disbelief of the fermentation technologists, Will, Delbrück, Wehmer, and even Stavenhagen, was as sharp and unanimous as the enthusiasm of the immunologists and enzymologists, Duclaux, Roux, Fernback, and Bertrand, (...) and of Pfeffer, the experimental plant physiologist. Other skeptics—Voit, Kupffer, and Fischer—were conservatives in traditional fields. In all these cases it seems clear that professional commitments and outlook profoundly influenced the reception of zymase.In some cases there is a correlation with a specific earlier statement favoring the protoplasm theory or predicting a fermentation enzyme. Reynolds Green is a striking case of both. In 1893 he stated his belief that life processes in higher plants and fungi were identical, both being mediated by protoplasm.109 Thus he claimed that digestion was not carried out by enzymes, as in higher animals, but by the whole protoplasm, and so too fermentation in yeast: “All the metabolic processes must be carried out in the unicellular organism in the same mass of protoplasm.”110 But Green also insisted that there was no essential difference between “organized” and “unorganized ferments”; enzymes were simply more highly differentiated and specialized forms of primitive protoplasm. He spoke of “the alcoholic ferment” (that is, enzyme), and of intracellular enzymes—very advanced beliefs for 1893. Thus it is understandable why Green saw no reason to doubt his first negative results with yeast juice, and rushed into print. But it is also understandable that he persisted and soon became an outspoken advocate of Buchner's view; like Wroblewski and Pfeffer, he had already accepted the idea of an intracellular fermentation enzyme.The physiological chemists also fit the pattern in a special way. Physiological chemistry is generally regarded as the source of biochemistry; indeed, many early biochemists were trained in physiological chemistry, and imbibed there a progressive interest in enzymes and metabolism. It is not surprising, therefore, that on the whole Neumeister, Madfadyen, Wroblewski, and Loew accepted cell-free fermentation. But what is surprising, and significant, is the diversity of opinion in this group, from Abeles' living protoplasm to Wroblewski's organized array of active proteins. The feelings of the physiological chemists were mixed, and there was enough of the old protoplasm view in Macfadyen's and even Wroblewski's views to allow Buchner to see them as attacks on zymase. The ideas of physiological chemistry were also changing; the idea of protoplasm was already adjusting to the new interest in enzymes in the early 1890's. But in contrast to immunochemistry, the change in physiological chemistry was gradual, uneven, undramatic, and relatively invisible. For the new biochemistry, the tradition of physiological chemistry was the source of traditional conservatism as well as of new ideas of enzymes.In general, then, I claim that it was not experimental facts that determined attitudes toward zymase so much as previous commitments, experience, and expectations. Initially, at least, zymase was less a determinant of opinion than a touchstone of pre-existing opinion. Like a prism, it revealed the spectrum of existing attitudes toward vital phenomena.Also relevant here is the fact that the experimental evidence was entirely ambiguous; the interpretation of Buchner's experiments with antiseptics or dried yeast depended entirely on how far one was willing to stretch the scope of the terms “protoplasm” and “enzyme”. Likewise, how important one judged the instability of zymase to be, or the low level of in vitro activity, depended largely on one's point of view. There was no crucial experiment, no certain proof. Logically zymase could be regarded as protoplasm. A. Fischer did so in 1900;111 Macfadyen was still wavering in 1907;112 and Beijerinck was holding out as late as 1916.113 There were undoubtedly others. Besides the special case of Reynolds Green and the technologists, there are no recorded cases of conversion.But if there was no evidence to convert a dedicated protoplasmist, there was plenty to encourage a dedicated belief in the enzyme theory, and that, I believe, is precisely what happened. The arguments of Buchner et al in support of zymase had the greatest effect not on the protoplasmists but on those who were already predisposed toward the biochemical view. The zymase debate enabled the emerging group of biochemists to recognizethemselves as a group with a community of out-look and objectives; it brought the issue of protoplasm vs. enzyme into the open and gave it a specific and concrete issue on which to turn. The debate sharpened the biochemists' awareness that their point of view was becoming the new mainstream of biochemical thought.All this of course had an important secondary effect on those who opposed the new view, or who were not immediately concerned with it. After the zymase debate, it would have been almost impossible to ignore the new ideas; the dramatic and wide publicity the debate enjoyed would have made it difficult not to take sides. Buchner's successful defense of zymase itself became an important influence on opinion; the new movement had to be looked at with respect. But the primary effect of the debate, I assert, was on those who were already inclined to the new view. The outcome was not a mass conversion of individuals, nor the ejection of one idea by another. The sides probably did not change much; the real change was in the way each side regarded itself and its place in history. The zymase debate may perhaps best be regarded as a process of selection. Buchner's party became aware of itself as the new progressive point of view, while those holding the traditional view could no longer expound it publicly without appearing obstinate or old-fashioned. Thus the way was clear for the gradually wider establishment of the new ideas, especially among the new generation of biochemists. In this specific sense, the acceptance of zymase was a social phenomenon.This way of looking at the zymase debate also illuminates its coincidence with the emergence of biochemistry as a profession. The new professional trappings and organizations were the social manifestation of the new self-awareness gained from the zymase controversy. One of the most important effects on those disposed toward the new view was the awareness of an intellectual community and of the need to give that community social forms. The almost mythical importance of Buchner's “victory” over the old protoplasm theory that later became current is readily understandable. It was a useful ideology for a group anxious to assert the novelty of their approach, a novelty which they in fact felt quite keenly.But if the primary effect of the zymase controversy was on those predisposed to accept zymase, then obviously the success of zymase depended on the fact that change had already begun to occur. Indeed, one of the most striking, and again unexpected, results of this study is the extent to which the importance of enzymes was already recognized in the early 1890's. The new immunology clearly pointed the way. Macfadyen and Hans Buchner were looking for active proteins inside the cell in 1893. Reynolds Green, Wroblewski, and Pfeffer had all anticipated the discovery of a fermentation enzyme. Other discoveries in enzymology in the 1890's pointed the same way.114 Moreover, it is clear from this study that the old protoplams theory was adapting to the new discoveries concerning the importance of enzymes. The sidechains of the old protoplasm molecule were simply reinterpreted as enzymes, as in Wroblewski's theory, for example, or in Paul Ehrlich's extremely influential “sidechain theory” of antibody formation (1897). Despite the later views of Hopkins et al., the old protoplasm and the new enzyme theories were not irreconcilable; a continuity of development had already begun when zymase came so dramatically on the scene. Buchner himself observed that the difference between the two views had become largely verbal; in retrospect we might say, not verbal, but social and historical. The gap between the continuous change in ideas and the contemporary feeling of sharply discontnuous change is a measure of the elusive but real social and historical implications of the zymase debate, of the demise of an old establishment, and the emergence of a new.In retrospect, then, it is clear that a trend was already under way in various quarters when zymase appeared. But it was still a collection of isolated and dispersed events. The zymase controversy made the trend visible and gave it a dramatic unity. The debate influenced those who had already begun to change. It was so effective because things had begun to change and because it coincided with the direction of that trend. (shrink)

The standard representation of the Central Dogma (CD) of Molecular Biology conspicuously ignores metabolism. However, both the metabolites and the biochemical fluxes behind any biological phenomenon are encrypted in the DNA sequence. Metabolism constrains and even changes the information flow when the DNA‐encoded instructions conflict with the homeostasis of the biochemical network. Inspection of adaptive virulence programs and emergence of xenobiotic‐biodegradation pathways in environmental bacteria suggest that their main evolutionary drive is the expansion of their metabolic networks towards (...) new chemical landscapes rather than perpetuation and spreading of their DNA sequences. Faulty enzymatic reactions on suboptimal substrates often produce reactive oxygen species (ROS), a process that fosters DNA diversification and ultimately couples catabolism of the new chemicals to growth. All this calls for a revision of the CD in which metabolism (rather than DNA) has the leading role. (shrink)

In the first decades of the twentieth century, the process of photosynthesis was still a mystery: Plant scientists were able to measure what entered and left a plant, but little was known about the intermediate biochemical and biophysical processes that took place. This state of affairs started to change between the two world wars, when a number of young scientists in Europe and the United States, all of whom identified with the methods and goals of physicochemical biology, selected (...) photosynthesis as a topic of research. The protagonists had much in common: They had studied physics and chemistry (although not necessarily plant physiology) to a high level; they used physicochemical methods to study the basic processes of life; they believed these processes were the same, or very similar, in all life forms; and they were affiliated with institutions that fostered this kind of study. This set of cognitive, methodological, and material resources enabled these protagonists to transfer their knowledge of the concepts and techniques from microbiology and human biochemistry, for example, to the study of plant metabolism. These transfers of knowledge had a great influence on the way in which the biochemistry and biophysics of photosynthesis would be studied over the following decades. Through the use of four historical cases, this paper analyzes these knowledge transfers, as well as the investigative pathways that made them possible. (shrink)

Mindfulness for the High Performance World provides a unique approach to mindfulness training, built upon the principles of Buddhist philosophy written in line with the Dalai Lama’s description of meditation and mindfulness as “Science of the Mind”. This unique volume explores mindfulness as a learnable skill in context with the underpinnings of the teachings of Eastern psychology. The authors, Norm, a physician, cancer researcher and triathlete and Karolynn, a psychotherapist, mindfulness meditation teacher and marathoner, live and work in a high-stress, (...) high-expectation world. Their approach is rooted in an understanding that thoughts produce biochemical and physiological changes and provides a strategic framework to instruct an individual on how to categorize types of thoughts. After harnessing this ability, one is positioned to become both more aware of his or her thoughts as well as the specific patterns of sensations they produce, or Sentinel SitesSM. The awareness of what the mind is doing and the ability to interrupt a thought pattern and/or control the response almost instantly leads one to having a healthier life, improved relationships with others and better adaptability to one’s environment. Emphasizing the importance of physical activity and nutrition, the authors present a systematic approach for people who want to learn and incorporate mindfulness and transform how they live without having to divert their lives and careers. Offering itself as an accessible and skill-based introduction to the principles, practices, and benefits of mindfulness, Mindfulness for the High Performance World is a useful resource for students, athletes and professionals living and working in high-performance, high-stress environments and also for mindfulness practitioners seeking to deepen their skill level. (shrink)

This study examined the cognitive mechanism underlying acute stress in creative cognition among individuals with high and low trait anxiety. Specifically, cognitive inhibition was assessed using the flanker task during acute stress. Fifty-two participants (26 high trait anxiety, 26 low trait anxiety) (mean age = 18.94 years) underwent stress induction via the Trier Social Stress Test (TSST). They all completed the Alternative Uses Test (AUT) and the Remote Associates Test (RAT) before and after the TSST. Biochemical markers (salivary cortisol (...) and salivary alpha amylase) were recorded at regular intervals. The results showed that cognitive inhibition was influenced by trait anxiety and acute stress. Compared to before experiencing acute stress, there was a lack of cognitive inhibition in low trait anxious individuals and they performed better in AUT (fluency) after acute stress, whereas high trait anxious individuals showed a decreased interference effect and reduced performance in AUT (fluency, flexibility, and originality). In the RAT, there were shorter response times and increased accuracy after acute stress in both high and low trait anxiety groups. Thus, we suggest that cognitive control, which modulates changes in acute stress, influences creative cognition. These findings provide evidence that inhibition control mediates the effect of stress on the creativity of individuals with different trait anxiety. (shrink)

The environmentally responsive molecular chaperone Hsp90 assists the maturation of many key regulatory proteins. An unexpected consequence of this essential biochemical function is that genetic variation can accumulate in genomes and can remain phenotypically silent until Hsp90 function is challenged. Notably, this variation can be revealed by modest environmental change, establishing an environmentally responsive exposure mechanism. The existence of diverse cryptic polymorphisms with a plausible exposure mechanism in evolutionarily distant lineages has implications for the pace and nature of (...) evolutionary change. Chaperone‐mediated storage and release of genetic variation is undoubtedly rooted in protein‐folding phenomena. As we discuss, proper protein folding crucially affects the trajectory from genotype to phenotype. Indeed, the impact of protein quality‐control mechanisms and other fundamental cellular processes on evolution has heretofore been overlooked. A true understanding of evolutionary processes will require an integration of current evolutionary paradigms with the many new insights accruing in protein science. BioEssays 26:348–362, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

Irreversibility, it is claimed, is a much broader concept than is entropy increase, as is shown by the occurrence of certain processes which are irreversible without seeming to involve any intrinsic entropy change. These processes include the spreading outwards into space of particles, or of radiation, and they also include certain biological and mental phenomena. For instance, the irreversible and treelike branching which is characteristic of natural evolution is not entropic when it is considered in itself—i.e. in abstraction from (...) accompanying biochemical and physiological activity. What appears to be the common feature of all forms of irreversibility is the fanning out of trajectories, new entities or new states, in the temporal direction towards the future. (shrink)

Biochemists investigating the problem of the vitamins in the early years of the twentieth century were working without an object, as such. Although they had developed a fairly elaborate idea of the character of the ‘vitamine’ and its role in metabolism, vitamins were not yet biochemical objects, but rather ‘functional ascriptions’ and ‘explanatory devices’. I suggest that an early instance of the changing status of the object of the ‘vitamins’ can be found in their stabilization, through the course of (...) World War I, as bio-political objects for the British and Allied war effort. Vitamins emerged as players, active agents, in Britain’s wartime bio-political problems of food distribution and population health and because of this they became increasingly real as bio-political objects, even prior to their isolation as bio-chemical molecules. I suggest that the materiality of our biology has agency in the development of political regimes and schemes. (shrink)

CHARLES DUPRAS | : L’épigénétique est un champ d’études qui s’intéresse aux modifications biochimiques et aux changements dans la structure tridimensionnelle de l’ADN ayant pour effet de contraindre ou de faciliter la lecture et l’expression des gènes. Au cours des dix dernières années, l’épigénétique a attiré l’attention d’un nombre croissant de chercheurs en sciences sociales, puisqu’elle semble venir confirmer, cette fois sur le plan moléculaire, le rôle déterminant de l’environnement développemental des personnes dans la configuration de leur individualité biologique et (...) dans la programmation de leur santé future. Cet article se penche sur les implications épistémologiques potentielles de l’épigénétique. Nous distinguons et décrivons trois perspectives socio-anthropologiques complémentaires, adoptées par différents auteurs, sur le rapprochement des concepts de « nature » et de « culture » par l’épigénétique : la socialisation du biologique, la biologisation du social et la superposition nature-culture. | : Epigenetics is a field of study that focuses on biochemical modifications and changes in the tridimensional structure of DNA that have the effect of constraining or facilitating the reading and expression of genes. Over the last ten years, epigenetics has captured the attention of several social scientists since it appears to confirm, this time at the molecular level, the determining role of the developing environment of people in configurating their biological individuality and programming their future health. This article discusses the potential epistemological implications of epigenetics. It distinguishes and describes three complementary socio-anthropological perspectives, taken by different authors, on the rapprochement of the concepts “nature” and “nurture” by epigenetics: the socialization of the biological, the biologization of the social, and the superimposition nature-nurture. (shrink)

One popular recombinant DNA tool is the EcoRI endonuclease, which cleaves DNA at GAATTC sites and serves as a paradigm for sequence specific DNA‐enzyme interactions. The recently revised X‐ray crystal structure of an EcoRI‐DNA complex reveals EcoRI employs novel DNA recognition motifs, a four α‐helix bundle and two extended chains, which project into the major groove to contact substrate purines and pyrimidines. Interestingly, pyrimidine contacts had been predicted based on genetic and biochemical studies. Current work focuses on the EcoRI (...) active site structure, enzyme and substrate conformational changes during catalysis, and host‐restriction system interactions. (shrink)

Apoptosis (programmed cell death) is an evolutionarily conserved cellular process, important for development and homeostasis(1). Most apoptotic cells share a common set of morphological and physiological characteristics that distinguish them from necrotic deaths(2). While genetic studies have indicated that these characteristic changes result from the activation of an endogenous ‘suicide program’(3), little is known about the nature of this program and the molecular events underlying these changes. Two recent papers(4,5) describing cell‐free extracts that reproduce several of the characteristic changes observed (...) in apoptotic cells promise to make these phenomena accessible to biochemical analysis. (shrink)

Background: The prevalence of anxiety and depression in young students is associated with biosocial factors and scholastic stress. However, few studies have evaluated emotional-affective symptoms that are related to the immune system and antioxidant parameters in young individuals without diagnoses of affective disorders.Aim: This study aims to assess the relationship between emotional-affective symptoms and glutathione concentrations and CD4 and CD8 lymphocyte counts in college students.Methods: College students completed standardized psychometric instruments, including the Perceived Stress Scale, Hamilton Anxiety Scale, Beck Depression (...) Inventory, Familiar Social and Friends Support Scale, and Rosenberg Scale. Blood samples were biochemically analyzed. Analyses of variance were conducted between four groups according to symptom severity.Results: A considerable prevalence of stress, anxiety, and depression symptoms was observed and negatively correlated with self-esteem and socio-familiar support. Perceived stress was sexually dimorphic. Although biochemical parameters were within reference ranges, glutathione, CD4, and CD8 tended to be lower in participants with anxiety and depression symptoms, which may be of predictive value.Conclusion: The relationship between antioxidant/immune parameters and socio-affective scores is latent in undiagnosed college students who might develop affective disorders. The findings suggest that during the initial development of affective disorders, stress management strategies should be implemented to help college students cope with the academic load and monitor negative changes in their physiological state. (shrink)

Stewart and Korol contend that obesity is benign. In support of their position they have focussed on selected papers that do not take into consideration key realities. Their attempt to minimise the impact of obesity appears to centre on how difficult it can be to lose weight by diet alone and problems with measurements of obesity, while failing to acknowledge the specific and well-documented impact of deleterious biochemical alterations arising from central obesity. Stewart and Korol also do not point (...) out the considerable controversy with the fat but fit concept. Whether looping from above or below, nothing changes the biochemical realities of central obesity. Above all, Stewart and Korol never once mention the benefits of obesity prevention, rather focussing on the difficulties of losing weight. Thus, respectfully, a word of caution is put forward on the views of Stewart and Korol regarding obesity. (shrink)

It is tempting to invoke organismal selection as perpetually optimizing the function of any given gene. However, natural selection can drive genic functional change without improvement of biochemical activity, even to the extinction of gene activity. Detrimental mutations can creep in owing to linkage with other selectively favored loci. Selection can promote functional degradation, irrespective of genetic drift, when adaptation occurs by loss of gene function. Even stabilizing selection on a trait can lead to divergence of the underlying (...) molecular constituents. Selfish genetic elements can also proliferate independent of any functional benefits to the host genome. Here we review the logic and evidence for these diverse processes acting in genome evolution. This collection of distinct evolutionary phenomena – while operating through easily understandable mechanisms – all contribute to the seemingly counterintuitive notion that maintenance or improvement of a gene's biochemical function sometimes do not determine its evolutionary fate. (shrink)

Base pair mismatches in DNA arise from errors in DNA replication, recombination, and biochemical modification of bases. Mismatches are inherently transient. They are resolved passively by DNA replication, or actively by enzymatic removal and resynthesis of one of the bases. The first step in removal is recognition of strand discontinuity by one of the MutS proteins. Mismatches arising from errors in DNA replication are repaired in favor of the base on the template strand, but other mismatches trigger base excision (...) or nucleotide excision repair (NER), or non‐repair pathways such as hypermutation, cell cycle arrest, or apoptosis. We argue that MutL homologues play a key role in determining biologic outcome by recruiting and/or activating effector proteins in response to lesion recognition by MutS. We suggest that the process is regulated by conformational changes in MutL caused by cycles of ATP binding and hydrolysis, and by physiologic changes which influence effector availability. (shrink)

Mechanisms occurring at the atomic level are now known to drive processes essential for life, as revealed by quantum effects on biochemical reactions. Some macroscopic characteristics of organisms may thus show an atomic imprint, which may be transferred across organisms and affect their evolution. This possibility is considered here for the first time, with the aim of elucidating the appearance of an animal innovation with an unclear evolutionary origin: migratory behaviour. This trait may be mediated by a radical pair (...) (RP) mechanism in the retinal flavoprotein cryptochrome, providing essential magnetic orientation for migration. Isotopes may affect the performance of quantum processes through their nuclear spin. Here, we consider a simple model and then apply the standard open quantum system approach to the spin dynamics of cryptochrome RP. We changed the spin quantum number (I) and g‐factor of hydrogen and nitrogen isotopes to investigate their effect on RP's yield and magnetic sensitivity. Strong differences arose between isotopes with I = 1 and I = 1/2 in their contribution to cryptochrome magnetic sensitivity, particularly regarding Earth's magnetic field strengths (25–65 µT). In most cases, isotopic substitution improved RP's magnetic sensitivity. Migratory behaviour may thus have been favoured in animals with certain isotopic compositions of cryptochrome. (shrink)

The biopsychosocial model was initially proposed to overcome the normative assumption that human diseases are exclusively due to disordered biochemical and/or neurophysiological processes. The model attempts to explain how expectations, thoughts and feelings modify the patient’s motivations to deal with illness and recovery. By considering the physical health in this perspective, healthcare professionals may test the importance of socially and culturally shared principles in alleviating illness experience. The entire biopsychosocial hierarchy may thus appear as a complex network of relationships (...) between the strict logic of scientific explanations and the emotional sustainability with which beliefs may either be defended, changed or even refused. In this paper, we aim at reviewing some of the evidence-based biomedical and psychological findings that provide a unified framework for the biopsychosocial model as a multilevel integrative process. To tackle this objective, we propose to approach the model in biosemiotic terms. It is our contention that the entire biopsychosocial hierarchy could be better understood if approached biosemiotically and the multilevel interconnection of this hierarchy re-examined in the light of a collaborative meaning-making process. (shrink)

Postpartum mood disorders develop shortly after childbirth in a significant proportion of women and have severe effects. Two evolutionary explanations are currently available. The first is that poor postpartum mental health is a consequence of an evolutionary trade-off – a compromise of neurological changes in the maternal brain during pregnancy which, on the one hand, maintain pregnancy, and on the other, increase the likelihood for postpartum women to develop psychopathology. The second explanation is that poor postpartum mental health is a (...) disease of civilization. This theoretical paper demonstrates that both explanations ignore the crucial event of childbirth. I elaborate on environmental features of childbirth, a physiological process that is substantially different in the current versus evolutionary childbirth and postpartum setting, and argue that maternal brain neuroplasticity and biochemical alterations are not an evolutionary trade-off, but an adaptation. Additionally, the incidents of poor postpartum mental health are better viewed as a maladaptation of the typical modern environments – an evolutionary mismatch. Thus, the potential to suffer from poor mental health in postpartum is an external, contingent happening, dependent on contemporary childbirth and postpartum environments, and not due to any essential property women possess as a result of evolutionary compromise. In fact, women are probably adapted to feel like superwomen right after birth, a state of mind that is an aid in adapting to motherhood. Distinguishing between evolutionary concepts in the context of pregnancy, birth, and motherhood is vital for developing more accurate preventions and interventions. (shrink)

In their environment, plants are continuously submitted to natural stimuli such as wind, rain, temperature changes, wounding, etc. These signals induce a cascade of events which lead to metabolic and morphogenetic responses. In this paper the different steps are described and discussed starting from the reception of the signal by a plant organ to the final morphogenetic response. In our laboratory two plants are studied: Bryonia dioica for which rubbing the internode results in reduced elongation and enhanced radial expansion and (...) Bidens pilosa for which the response occurs at distance, hence pricking the cotyledon of a plantlet induces the growth inhibition of both the hypocotyl and the axillary bud of the pricked cotyledon. Reception of the signal and transmission of the message. In Bryonia the signal is received by epidermal cells while in Bidens they are the cells adjacent to the midrib of the cotyledon which receive the mechanical signal. In both plants the message is transmitted via a wave of electric depolarization. This latter is composed of an action potential associated with a slow wave whose transmission rates are respectively 1cm s−1 and 1 mm s−1. Recent results have shown the involvement of Ca2+ in the triggering of the slow wave and the role of the H+ pump during the slow wave. Transient and fast biochemical responses. An entry of extraceilular Ca2+ into the cells and a transient increase in IP3 occur within seconds following the mechanical stimulus. At the same time, the membrane becomes more fluid, correlated with qualitative changes in phospholipids. The rapid increase in the concentration of peroxidated lipids may be correlated with ethylene biosynthesis which is stimulated after rubbing. Other parameters such as cytoplasmic pH, relative water content, hydric potential, membrane potential and modifications of K+, Mg2+-ATPase and Ca2+-ATPase activities, play a key role in the early responses induced by the traumatisms. Irreversible-biochemical responses. The mechanical stimulus performed on a Bryonia internode induces an acceleration of: i) enzymatic activities related to the lignification, ii) esterification of phenolic acids in the cell wall. Consequently the lignification process is accelerated. Storage of the information. After being received by the target cells the information can be stored during several days before being expressed. At the level of cotyledonary bud, the first message, previously stored, can be expressed or not by a second treatment. Bidens thus behaves as if it was able to “store” and to “retrieve” morphogenetic messages, using a sort of rudimentary memory. The nuclei of the bud cells of the pricked cotyledon show that these cells, initially in G2 phase, divide and then remain in the G1 phase. In Bryonia, calli derived from young stimulated internodes, keep thigmomorphogenetic characteristics during several weeks. In the last part of this paper the particularity of our plant model which permits a study of the transmission and storage of the message, is underlined. The links between the different steps induced by the stimulus are discussed. Special attention is devoted to second messengers and to the amplification of the message. (shrink)