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PubMed2003

[Stress, adaptation, and self-organization: balancing processes facilitate health and survival].

BACKGROUND: Stress is of growing significance not only in established industrial countries. Preventive medical aspects are becoming important in association with the stress phenomenon. OBJECTIVE: Discussing the correlation between stress and health (or disease). Does a state of dynamic balance play a role in the context of stress, allostasis, adaptation, and self-organization? What kind of influence do balancing processes have on health and survival? RESULTS: Stress itself is neither harmful nor healthy. Instead, it represents a fundamental biological principle that is associated with vivacity and that facilitates adaptation, dynamic balance, self-organization, and survival within a constantly changing environment. Stress may also be of significance for biological evolution. A crucial part of the physiological concept is the autoregulatory stress response. Thereby, stress may enhance biological creativity and health, but may also lead to allostatic load and disease. Not only exogenous stressors, but also the subject itself decide upon the individual stress outcome. CONCLUSIONS: Dynamic balances characterize life and survival. Further, they are crucial for health processes. Stress may facilitate a 'healthy' balance or enhance disease processes likewise. Hence, the subjective inner structure or self-organization of an organism determines--in addition to exogenous factors--individual consequences of stress. Therefore, prevention should strengthen the subject and amplify self-capacity and responsibility. Professional stress-management strategies or integrative/mind-body medical programs may be helpful.

Disease Susceptibility↗
PubMed1987

Chemical selection, diversity, teleonomy and the second law of thermodynamics. Reflections on Eigen's theory of self-organization of matter.

Two fundamental properties of animate matter, specific complexity and purposeful organization (teleonomy), are traced to their origin, applying Eigen's theory of self-organization of matter. Template-replicating copolymers possess the three dynamic properties that are essential for prebiotic evolution: autocatalysis, diversification and selection. By autocatalysis, even a single microscopic molecule replicates exponentially to macroscopic quantities. By diversification, it extends to a divergent distribution of such molecules. By selection, the distribution converges to a 'quasi-species' that possesses properties like 'survival' and 'adaptation' to its environment. These are teleonomic properties that evolved from a nonteleonomic distribution by selection. Alternating divergent and convergent courses of chemical evolution lead such distributions to ever-growing complexity, including mutual catalytic interactions between the template-replicating copolymers and their chemical environment. Thus, chemical evolution may have started from even a single step, a de novo synthesis of a template-replicating copolymer, and arrived at a primordial living cell, just as biological evolution has started from a primordial cell and arrived at the biological world of today.

DNA Replication↗
PubMed1993

The D/H ratio and the evolution of water in the terrestrial planets.

The presence of liquid water at the surface of the Earth has played a major role in the biological evolution of the Earth. None of the other terrestrial planets--Mercury, Venus and Mars--has liquid water at its surface. However, it has been suggested, since the early seventies, from both geological and atmospheric arguments that, although Venus and Mars are presently devoid of liquid water, their surfaces could have been partially or completely covered by water at some time of their evolution. There are many possible diagnostics of the long-term evolution of the planets, either from the present characteristics of their surfaces or from their present atmospheric compositions. Among them, the present value of the D/H ratio is of particular interest, although its significance in terms of long term evolution has been challenged by some authors. Recent progress has been made in this field. We now have evidence for higher D/H ratios on Mars and Venus than on Earth, with an enrichment factor of the order of 5 on Mars, and about 100 on Venus. Any scenario for the evolution of these planets must take this into The most recent models on the evolution of Mars and Venus are reviewed in light of these new measurements.

Atmosphere↗
PubMed2000

The molecular evolution of pyridoxal-5'-phosphate-dependent enzymes.

The pyridoxal-5-phosphate-dependent enzymes (B6 enzymes) that act on amino acid substrates are of multiple evolutionary origin. The numerous common mechanistic features of B6 enzymes thus are not historical traits passed on from a common ancestor enzyme but rather reflect evolutionary or chemical necessities. Family profile analysis of amino acid sequences supported by comparison of the available three-dimensional (3-D) crystal structures indicates that the B6 enzymes known to date belong to four independent evolutionary lineages of homologous (or more precisely paralogous) proteins, of which the alpha family is by far the largest. The alpha family (with aspartate aminotransferase as the prototype enzyme) includes enzymes that catalyze, with several exceptions, transformations of amino acids in which the covalency changes are limited to the same carbon atom that carries the amino group forming the imine linkage with the coenzyme (i.e., Calpha in most cases). Enzymes of the beta family (tryptophan synthase beta as the prototype enzyme) mainly catalyze replacement and elimination reactions at Cbeta. The D-alanine aminotransferase family and the alanine racemase family are the two other independent lineages, both with relatively few member enzymes. The primordial pyridoxal-5-phosphate-dependent enzymes apparently were regio-specific catalysts that first diverged into reaction-specific enzymes and then specialized for substrate specificity. Aminotransferases as well as amino acid decarboxylases are found in two different evolutionary lineages. Comparison of sequences from eukaryotic, archebacterial, and eubacterial species indicates that the functional specialization of most B6 enzymes has occurred already in the universal ancestor cell. The cofactor pyridoxal-5-phosphate must have emerged very early in biological evolution; conceivably, organic cofactors and metal ions were the first biological catalysts. In attempts to stimulate particular steps of molecular evolution, oligonucleotide-directed mutagenesis of active-site residues and directed molecular evolution have been applied to change both the substrate and reaction specificity of existent B6 enzymes. Pyridoxal-5-phosphate-dependent catalytic antibodies were elicited with a screening protocol that applied functional selection criteria as they might have been operative in the evolution of protein-assisted pyridoxal catalysis.

Alanine Racemase↗
PubMed1980

General theory of evolution.

The biological, neural, cultural and technical evolutions and their phenomena have been explored, and on the basis of our findings the formation of a general theory of evolution has been undertaken. In each of the systems studied, the presence of structural building units, excitable structures and an energy-flow going through the system can be observed. Under the organizing effect of this energy-flow, the spontaneous generation of the replicative information begins and the structures of the system establish functional relations with each other. It can be demonstrated that the evolution of structures has a replicative character. The evolution goes through a phase of non-identical replication, and reaches the phase of identical replication. The parts of the system become separated, that is, compartments develop within it. The replicative information becomes compartmentalized and it converges. As a consequence of the convergence, the compartments compose new structural units which is tantamount to the development of new evolutional levels. The direction of evolution is determined by the growth of replicative information, and this process is concluded when the total system becomes one replicative unit. In the last part of the paper a few of the basic principles of evolution concerning matter, energy and information are drawn up.

Animals↗
PubMed1994

The paradigm of biologically closed electric circuits (BCEC) and the formation of an International Association (IABC) for BCEC systems.

Matter is condensed energy. Matter derived from electromagnetic energy, supplied with the electrically powered BCEC systems (biologically closed electric circuits) inherits prerequisites to become biological matter. This is possible because mechanisms of BCEC systems contain the capacity to initiate structuring and functioning of matter. The principle of BCEC systems, their actual and potential importance for structure and function in biology and medicine, has been presented only in the form of a survey. Only few examples of the impact of the BCEC systems have been described. For detailed information, the reader is advised to take part of the original background articles by means of the reference list, which extends beyond the selected descriptions. Thereby it is hoped that the reader may get an understanding of the central biological role of the BCEC systems. They represent in this partial theory of the biological evolution a key mechanism which may provide the important primary steps that are necessary for the transfer of non-biological into biological matter. Second, also other factors are evidently contributing to biological differentiation, including for instance the principle of differential selection of species. Due to their basic role, the BCEC systems can nevertheless be recognized to be involved in the majority of structural and functional expressions in biology. This rests on the fact that our physical world once developed from energy and specifically its representation of electric energy. It has also been emphasised that electric energy is equivalent to the remarkable Oriental concept of Qi ("life energy"). Differences are predominantly a matter of semantics.

Animals↗
PubMed2001

Myelomastocytic overlap syndromes: biology, criteria, and relationship to mastocytosis.

Although mast cells (MC) appear to be myeloid cells, MC lineage involvement in myelogenous malignancies has been described only rarely. Based on clonal evolution, biology of afflicted cells, and disease criteria, three major groups of patients have been recognized: The first meets criteria for both diagnoses 'systemic mastocytosis' and 'associated hematologic clonal non-mast cell lineage disease (AHNMD)'. In such patients, myeloproliferative (MPS) or myelodysplastic syndromes (MDS), or acute myeloid leukemia (AML) is diagnosed apart from mastocytosis. In a second group of patients, large numbers of very immature MC-lineage cells (metachromatically granulated blast-like cells) are detectable, but the criteria to diagnose mastocytosis are not met. These patients have advanced myeloid neoplasms (MDS or MPS with blast cell increase, or AML) and variably suffer from mediator-related symptoms (flush, GI-tract ulcer, diarrhoea, coagulopathy). In some cases, the disease mimics mast cell- or basophilic leukemia. In contrast to basophilic leukemia, however, the metachromatic cells are strongly KIT+ and tryptase+. In contrast to true mast cell leukemia (MCL), MC do not form multifocal dense infiltrates in the bone marrow. Also, MC lack CD2 and CD25, and the C-KIT mutation Asp-816-Val. We propose the term 'myelomastocytic leukemia' or 'myelodysplastic mast cell syndrome' for these cases. In a third group of patients, myeloid neoplasms (MDS, MPS, AML) show constitutive expression of MC-associated antigens (tryptase, histamine) or mastocytosis-related gene defects (mutated C-KIT) without significant increase in metachromatic cells or criteria of mastocytosis. Whether these neoplasms display aberrant gene expression (or gene defects) or represent 'pre-pre-mast cell leukemias', remains unknown.

Antigens, Differentiation↗
PubMedDate not supplied

[Relative competitiveness of haploid and diploid yeast cells growing in a mixed population].

Saccharomyces cerevisiae was grown in a rich medium under the conditions of "quasi-continuous" cultivation and, after 200-300 generations, its diploid cells almost completely displaced haploid cells from the original mixed "haploid-diploid" population where the ratio between diploid and haploid strains was either 1:1 or 1:100. The cultivation at 40 degrees C did not change the relative competitive ability of haploids and diploids. When cells were cultivated in a rich medium at 6 degrees C or in a minimal medium at 30 degrees C, none of the strains showed an advantage over others for about 200 generations. Haploid cells had an advantage over diploid cells during "quasi-continuous" growth in the minimal medium at 30 degrees C. When the temperature was elevated to 40 degrees C, diploid cells displaced haploid cells from the mixed population. No advantage was found for diploid or haploid cells grown in a medium with an elevated KCl content (1.5 M). Haploid cells had an advantage over diploid cells when Pichia pinus was cultivated in a minimal medium. The results are discussed using the hypothesis about the diploid phase being fixed in the course of biological evolution.

Diploidy↗
PubMed1988

[The Parsonage-Turner syndrome and similar diseases. 29 cases].

Twenty nine cases of acute inflammatory brachial neuropathy were collected from 1969 to 1985. Only five cases could be considered as definite Parsonage Turner's "shoulder girdle" syndrome. The twenty four other cases were atypical with respect to this entity and were classified as symptomatic, evolutive, biological and/or associated forms. Symptomatic variants were present in twenty cases, consisting in distal or global motor deficit, or in painlessness. Evolution was atypical in four cases, with no recovery of motor deficit or relapsing course. Thirteen cases had abnormal CSF, usually with increase of protein content. Association with cutaneous manifestations or systemic diseases was found in nine cases. Beyond their individual differences, these twenty nine cases shared a common general profile of clinical presentation and evolution. This led to recognize the nosological relationships of these atypical cases with Parsonage-Turner's syndrome and to emphasize the similarities with Guillain-Barré syndrome.

Adolescent↗
PubMed2002

Evolving neural networks through augmenting topologies.

An important question in neuroevolution is how to gain an advantage from evolving neural network topologies along with weights. We present a method, NeuroEvolution of Augmenting Topologies (NEAT), which outperforms the best fixed-topology method on a challenging benchmark reinforcement learning task. We claim that the increased efficiency is due to (1) employing a principled method of crossover of different topologies, (2) protecting structural innovation using speciation, and (3) incrementally growing from minimal structure. We test this claim through a series of ablation studies that demonstrate that each component is necessary to the system as a whole and to each other. What results is significantly faster learning. NEAT is also an important contribution to GAs because it shows how it is possible for evolution to both optimize and complexify solutions simultaneously, offering the possibility of evolving increasingly complex solutions over generations, and strengthening the analogy with biological evolution.

Algorithms↗
PubMed1997

Hierarchical organization of biological systems and the structure of adaptation in evolution and tumorigenesis.

Biological systems are structurally organized according to patterns repeated at each hierarchical level. Complex units are composed of so-called interactors, systems that by cooperative interaction maintain the structure of the complex unit. Interactors are composed of large numbers of assemblies of complex units of a limited number of types of a lower hierarchical level. Thus, macromolecules, cells, organisms and ecological communities should be defined as complex units, and cellular organelles, organs and oligospecies populations as the interactors between those units. The similarity of organization at each level should make it possible to describe patterns of structure at one level and apply it to organization at another level. This was tested for the structural aspects of adaptation as viewed in a pathobiological context. Adaptation is then viewed as the result of stress seen at the level of the interactors or at the level of the lower complex units related to the type of stress. Subsequently, this structure of adaptation was applied to adaptation in biological evolution and tumorigenesis, which has led to the conclusion that stress is a driving force for both and that an increase in number of organisms or cells may precede heritable changes or mutations, respectively.

Adaptation, Physiological↗
PubMed2005

The prokaryote-eukaryote dichotomy: meanings and mythology.

Drawing on documents both published and archival, this paper explains how the prokaryote-eukaryote dichotomy of the 1960s was constructed, the purposes it served, and what it implied in terms of classification and phylogeny. In doing so, I first show how the concept was attributed to Edouard Chatton and the context in which he introduced the terms. Following, I examine the context in which the terms were reintroduced into biology in 1962 by Roger Stanier and C. B. van Niel. I study the discourse over the subsequent decade to understand how the organizational dichotomy took on the form of a natural classification as the kingdom Monera or superkingdom Procaryotae. Stanier and van Niel admitted that, in regard to constructing a natural classification of bacteria, structural characteristics were no more useful than physiological properties. They repeatedly denied that bacterial phylogenetics was possible. I thus examine the great historical irony that the "prokaryote," in both its organizational and phylogenetic senses, was defined (negatively) on the basis of structure. Finally, we see how phylogenetic research based on 16S rRNA led by Carl Woese and his collaborators confronted the prokaryote concept while moving microbiology to the center of evolutionary biology.

Bacteria↗