Information processing organs,mathematical mappings and self-organizing systems

A self-organizing system, which may be biological or man-made, adjusts itself in response to inputs from the surroundings. The input information is processed and transformed, so as to guide the system in accordance with a desired final state. The visual nervous system is considered, to illustrate some possible transformations or mappings, which may be employed by self-organizing systems. The mappings given as examples are linear, but there is evidence also for nonlinear mappings to explain the action of biological systems. The successive stages of adjustment in a self-organizing system can be treated as a feedback control process. Mathematically, feedback control of linear as well as nonlinear systems can be handled by using the principle of contraction mapping. The kind of control considered is flexible in the sense that a desired state of the system as a whole can be achieved through a variety of states of the individual parts. This leads to such questions as equivalence and classification which are also discussed in this paper.     

A relational theory of biological systems

The relational phenomena exhibited by metabolizing systems may be considered as special cases of those exhibited by a more general class of systems. This class is specified, and some of tis properties developed. An attempt is then made to apply these properties to a theory of metabolism by suitable specialization. A number of biologically significant theorems are obtained which apply directly to the theory of the free-living single cell. Among the results obtained are the following: On the basis of our model, there must always exist a component of the system which cannot be replaced or repaired by the system in the event of its inhibition or destruction. Under certain conditions, a metabolizing system possesses a component the inhibition of which will completely terminate the metabolic activity of the system. Furthermore a number of other diverse phenomena, such as the effects of a deficient environment, encystment phenomena, and even an indication of why a metabolizing system which represents a cell should possess a nucleus, follow in a straightforward fashion from our model.     

Cytokinesis through biochemical–mechanical feedback loops

Cytokinesis is emerging as a control system defined by interacting biochemical and mechanical modules, which form a system of feedback loops. This integrated system accounts for the regulation and kinetics of cytokinesis furrowing and demonstrates that cytokinesis is a whole-cell process in which the global and equatorial cortices and cytoplasm are active players in the system. Though originally defined in Dictyostelium, features of the control system are recognizable in other organisms, suggesting a universal mechanism for cytokinesis regulation and contractility.     

Catalysis of disulfide bond formation and isomerization in the Escherichia coli periplasm

Disulfide bond formation is a catalyzed process in vivo. In prokaryotes, the oxidation of cysteine pairs is achieved by the transfer of disulfides from the highly oxidizing DsbA/DsbB catalytic machinery to substrate proteins. The oxidizing power utilized by this system comes from the membrane-embedded electron transport system, which utilizes molecular oxygen as a final oxidant. Proofreading of disulfide bond formation is performed by the DsbC/DsbD system, which has the ability to rearrange non-native disulfides to their native configuration. These disulfide isomerization reactions are sustained by a constant supply of reducing power provided by the cytoplasmic thioredoxin system, utilizing NADPH as the ultimate electron source.     

ADRENALIN IN ANNELIDS : A CONTRIBUTION TO THE COMPARATIVE STUDY OF THE ORIGIN OF THE SYMPATHETIC AND THE ADRENALIN-SECRETING SYSTEMS AND OF THE VASCULAR MUSCLES WHICH THEY REGULATE.

1. The sympathetic nervous system and the adjuvant adrenalin-secreting system are found in their earliest form in the annelid kingdom, and consist of cells situated in the central nervous system which are the common ancestors of both, and which are both secretory and nervous in function. 2. These cells are developed in the annelid kingdom parallel with the development of a contractile vascular system, which possesses muscles comparable in physiological actions with the muscle of the vertebrate heart. 3. This vascular muscle is regulated by the processes of the common ancestral cells as well as by their secretory activity. 4. In the primitive form contractile rhythm is an intrinsic property of cardiac muscle; its nerve supply regulates the rhythm, it does not initiate it. The beat is therefore myogenic, not neurogenic. 5. The contractile vascular system of annelids is mainly branchial in function. The vertebrate heart has been derived from it by the growing around of the lateral body folds to form a new ventral surface.     

Pattern recognition and associative memory as dynamical processes in a synergetic system

We consider a model for associative memory and pattern recognition which was devised by Haken (1987b). This model treats the activity of the neurons as continuous variables and exploits an analogy with pattern formation in synergetic systems. The capability of such a system to act as associative memory is demonstrated by the reconstruction of faces which are partially offered to the system, and which are restored by the corresponding dynamical process. We demonstrate how this model can be cast into a form which is translation invariant and how partially hidden faces in scenes can be recognized by means of the control of attention parameters of specific patterns.     

On the kinetics of potential,electromotance, and chemical change in the excitable system of nerve

The kinetics of interaction between potential, chemical equilibrium, and electromotance in the excitable system of nerve are analyzed. The theoretical system has the following properties: It gives rise to two electromotances each of which depends directly on a chemical equilibrium. The equilibria are determined by the potential across the system. After a sudden potential shift the equilibria reach their new value with an exponential time course, the time constant of which is determined by the rate constants of the two reactions. The rate constants are different due to different activation energies. The two electromotances give rise to potentials of opposite sign. The total potential produced by the system is equal to the sum of the two potentials. The two equilibria are thus determined by any externally applied potential as well as by the sum of the internally produced potentials. The dependence of the equilibria on the potential is calculated from first principles. The equations which describe this system are solved by an analogue computer, which gives instantaneous solutions of the total internal potential as a function of time and any voltage applied from an external source. Comparison between recorded and computed action potentials shows excellent agreement under all experimental conditions. The electromotances might originate from a Ca⁺⁺—Na⁺—K⁺ exchange at fixed negative sites in the Schwann cell.     

Information Content,Complexity, and Uncertainty in Material Flow Analysis

Material Flow Analysis (MFA) is a useful method for modeling, understanding, and optimizing sociometabolic systems. Among others, MFAs can be distinguished by two general system properties: First, they differ in their complexity, which depends on system structure and size. Second, they differ in their inherent uncertainty, which arises from limited data quality. In this article, uncertainty and complexity in MFA are approached from a systems perspective and expressed as formally linked phenomena. MFAs are, in a graph‐theoretical sense, understood as networks. The uncertainty and complexity of these networks are computed by use of information measures from the field of theoretical ecology. The size of a system is formalized as a function of its number of flows. It defines the potential information content of an MFA system and holds as a reference against which complexity and uncertainty are gauged. Integrating data quality measures, the uncertainty of an MFA before and after balancing is determined. The actual information content of an MFA is measured by relating its uncertainty to its potential information content. The complexity of a system is expressed based on the configuration of each individual flow in relation to its neighboring flows. The proposed metrics enable different material flow systems to be compared to one another and the role of individual flows within a system to be assessed. They provide information useful for the design of MFAs and for the communication of MFA results. For exemplification, the regional MFAs of aluminum and plastics in Austria are analyzed in this article.     

Experimente zur binären Klassifikation von Mustern durch den Menschen

The human visual system is investigated using two types of experiments. In the first type, pairs of characters of different fonts are presented with superimposed additive gaussian noise. The error rates are obtained as a function of the signal-to-noise ratio. By comparison with the error rates of the optimal system it may be concluded, that the human system is suboptimal, that no filtering process is involved, and that there is a nonlinearity which depends on the signal-to-noise ratio. Those fonts are recognized best, which one would expect according to the optimal system. In the second type of experiments, pairs of handprinted characters are presented. It turns out that these characters are recognized by humans about as well as by an approximately optimal system. Again, those pairs of characters are recognized best, which one would expect according to the approximately optimal system.

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Die vorliegende Arbeit wurde mit Mitteln des Bundesministeriums für Bildung und Wissenschaft im Rahmen des Technologie-Programms durchgeführt.

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Von Herrn Dr. Reinig stammen die Aufbauten für die optischen Versuche.     

The numerical method for the optimal supporting position and related optimal control for the catalytic reaction system

This paper considers the numerical approximation for the optimal supporting position and related optimal control of a catalytic reaction system with some control and state constraints, which is governed by a nonlinear partial differential equations with given initial and boundary conditions. By the Galerkin finite element method, the original problem is projected into a semi-discrete optimal control problem governed by a system of ordinary differential equations. Then the control parameterization method is applied to approximate the control and reduce the original system to an optimal parameter selection problem, in which both the position and related control are taken as decision variables to be optimized. This problem can be solved as a nonlinear optimization problem by a particle swarm optimization algorithm. The numerical simulations are given to illustrate the effectiveness of the proposed numerical approximation method.     

Studies on the ultrastructure and histochemistry of the lymph system of Gastrodiscoides hominis (Paramphistoma: Digenea).

The lymphatic system of the paramphistome, Gastrodiscoides hominis consists of numerous fluid-filled branches embedded in parenchyma and surrounded by extracellular material and is closely associated with the major organ systems of the fluke. The lymph matrix consists of a cytoplasmic syncytium within which nuclei, mitochondria and various sized granules and membranous structures occur. The granules found throughout the lymph system morphologically resemble autophagosomes and lysosomes. The lymph system provides a storage site for proteins which can be broken down to amino acids via autophagy, for subsequent mobilization and transport to tissues undergoing active protein synthesis. Many branches of the lymph system are surrounded by specialized parenchymal cells referred to as juxta-lymphatic cells. These cells are apparently associated with autophagic degradation of sequestered lymph cytoplasm, which may serve as an additional mechanism for the mobilization and transport of precursor molecules throughout the fluke via the parenchymal network.     

6-Deoxy-D-glucose and D-xylose: Analogs for the study of D-glucose transport by mouse 3T3 cells

6-Deoxy-D-glucose and D-xylose, structural homomorphs of D-glucose that lack a 6-hydroxyl group or a 6-hydroxymethyl group, respectively, are transported efficiently by mouse 3T3 cells, with good affinity and high specificity for the D-glucose transport system. Since these analogs lack the 6-hydroxyl group, which is the site of phosphorylation of glucose by hexokinase, they are taken up and are recoverable from cells in an unchanged state. Thus, 6-deoxy-D-glucose and D-xylose offer advantages as transport substrates over 2-deoxy-D-glucose, which is phosphorylated by intercellular hexokinases, and 3-O-methyl-D-glucose, which shows a lower specificity for the D-glucose transport system.     

二种群生态系统的能量结构分析

每一个生命系统均存在一个能量系统与之相对应。能量进入生命系统后按生理的组织和功能进行分配,形成具有特定的能量传递关系,组分配置关系及相互关联形式的能量结构,这种结构是完成一定生命功能的物质基础,也是不同生命系统之间相互区别的重要特征。以二种群生态系统分析为例,从其能量的传输类型,配置和奇点的控制特性三个方面扼要地介绍了生命能量系统结构的概念和分析方法。     

Attention and memory model based on the principle of dominant and comparative function of the hippocampus

Six basic problems of attention are described in terms of the dominant focus by Ukhtomsky, which is simulated as a system of phase transitions in the brain. Theoretical and experimental arguments in favor of the existence of metastable states in the brain with the life time of about a second or more are deduced. This forms an approach to resolution of all the problems of interaction between attention and memory, binding, and central control. A neurobiological model of attention and memory is advanced, which integrates the system properties of dominanta by A.A. Ukhtomsky and comparator function of the hippocampus by O.S. Vinogradova. New literature evidence is given for the existence of the brain system of information processing with the hippocampus as a central executive.     

Amino acid transport in whole cells and membrane vesicles of Arthrobacter pyridinolis

Arginine, and several other amino acids, can only support growth of Arthrobacter pyridinolis if malate is also present in the medium. Arginine is transported by a high affinity lysine-arginine-ornithine-type transport system which is stimulated by malate in both whole cells and vesicles, is respiration-coupled, and appears to depend upon a respiration-generated membrane potential but not on a ΔpH. Arginine is also transported by a low-affinity system which transports canavanine. Studies of an arginine auxotroph suggest that the lysine-arginine-ornithine system may be the system of major physiological significance for arginine transport. Phenylalanine is one of a few amino acids which can act as sole source of carbon for A. pyridinolis. Transport of phenylalanine occurs by two kinetically distinct systems. Both of these transport systems are respiration-coupled, are not appreciably stimulated by malate either in cells or vesicles, but are markedly stimulated by ascorbate-phenazine methosulfate. Studies with inhibitors indicate that the transport systems for phenylalanine utilize both a ΔpH and a membrane potential.     

A molecular semiotic view of biology. Interferon and 'homeokine' as symbols.

A term "homeokine" was introduced as a generic name covering cytokines and protein hormones which serve the purpose of intercellular communication within the animal body for homeostasis and ontogenetic development. The homeokine system, in its complex way of functioning, seems to be analogous to another communication system, human language. Individual homeokine molecules are likened to words; they have meanings and are viewed as symbols, representing those conditions or events inside and outside the body which are relevant to homeostasis. Extending this view, any protein and other molecule can be considered to take on the character of sign, when integrated into a purposive system of higher hierarchy, because the molecule then represents a meaning relative to the system as a whole that is lacking in the isolated state. Living systems with their biological macromolecules as semantic units are constructed upon the principle of double articulation, just like human languages with words as the semantic units. The structure and function of a molecule (of protein and any other substance) are associated with each other, with various degrees of arbitrariness, as are the expression and the content of a sign in general. Namely the activities or the sign functions of biological molecules are determined by the organized system they belong to, and not vice versa.     

Predicting evolutionary potential. I. Predicting the evolution of a lactose-PTS system in Escherichia coli.

Genomes contain not only information for current biological functions, but also information for potential novel functions that may allow the host to adapt to new environments. The field of experimental evolution studies that potential by selecting for novel functions and deducing the means by which the function evolved, but until now it has not attempted to predict the outcomes of such experiments. Here I present a model system that is being developed specifically to examine the issue of what kind of information is most useful in predicting how novel functions will evolve. The system is the evolution of a Lac-PTS transport system and a phospho-beta-galactosidase hydrolase system as a novel pathway for metabolism of lactose in Escherichia coli. Two kinds of information, sequence-based phylogenetic inference and biochemical activity, are considered as predictors of which E. coli genes will evolve the required new functions. Both biochemical data and phylogenetic inference predict that the cryptic celABC genes, which currently specify a PTS-beta-glucoside transport system, are most likely to evolve into a PTS-lactose transport system. Phylogenetic inference predicts that the bglA gene, which currently specifies a phospho-beta-glucosidase, is most likely to evolve into a phospho-beta-galactosidase. In contrast, biochemical data predict that the cryptic bglB gene, which also currently specifies a phospho-beta-glucosidase, is most likely to evolve into a phospho-beta-galactosidase.