Application of information networks to a theory of vision

Some principles of information theory are utilized in the design of neural nets of the McCulloch-Pitts type. In particular, problems are considered where signals from several neurons must pass through a single one, thus resulting in a “bottleneck” in the flow of information, an abstract model of the corresponding bottleneck from the retina to the optic nerve. The first part of the paper deals with a construction of a McCulloch-Pitts net in which the redundancy in the messages originating in two neurons is utilized so that the messages can be sent over a single neuron with little loss of information. In the second part, messages from a set of neurons are “pumped” into two channel neurons. The optimum connection scheme is computed for this case, i.e, one resulting in a minimum loss of information. Possible biological implications of this approach are indicated.     

Signal propagation in 2-dimensional threshold cellular space

Summary A two-dimensional network of uniformly connected McCulloch-Pitts neurons is considered and signal propagations in the network are analyzed. The problems are set up in the framework of cellular space such that each cell is a copy of any given McCulloch-Pitts neuron and is connected to the nearest neighboring cells. It is assumed that the threshold value is positive and that there exists only one firing cell at the beginning. Then it is shown that essentially there are only four signal propagation patterns and a firing pattern at any time t can be obtained by such a superposition of the propagation patterns that includes the newly defined concept of dominance and assimilation. The exact formulae representing firing patterns at any time t are obtained for any finite rectangle cell space with constant 0 (i.e., non-firing) boundary condition and for the entire two-dimensional cellular space.     

A note on mathematical models for the interaction of neural elements

By introducing a plausible model for the initiation of axonal impulses the output is obtained as a function of the input incoming impulses. If the temporal aspects of the excitatory process resulting from the afferent impulses are sufficiently rapid one obtains the discontinuous or microscopic model of McCulloch-Pitts. If these are sufficiently slow a continuous model, such as Rashevsky’s one or two factor theory, is a natural model. But the linear relation between the strength of excitation of one axon and excitatory factor of the next will not in general hold. However, under conditions which are not too restrictive the linear relation with threshold can be considered as satisfactory approximation over a fairly wide range of values. This research was supported in whole or in part by the U. S. Air Force under Contract AF 49(638)-414 monitored by the Air Force Office of Scientific Research.     

Some remarks on the boolean algebra of nervous nets in mathematical biophysics

Recent demonstration by the author has shown that the fundamental equations of the mathematical biophysics of the central nervous system can be considered as describing the behavior of very large numbers of neurons, of which each one follows discontinuous laws, such as discussed by W. S. McCulloch and W. Pitts. In that light some of the old problems are discussed. The comparative merits of the “microscopic” and “macroscopic” approaches are discussed for the problem of the point to point correspondence between the retina and the cortex, with the number of connecting fibers much less than the number of cells. Some aspects of discrimination of intensities are also discussed. Finally, a few generalizations of the McCulloch-Pitts treatment are suggested, and a nervous network is constructed which illustrates some aspects of the perception of numbers.     

A note on the quantum-theoretic basis of primary genetic activity

In previous work (Bull. Math. Biophysics,23, 393–403, 1960) it was shown that, if primary genetic processes are of an essentially microphysical nature, the objects bearing the primary genetic information must act in a catalytic fashion. At the same time it was pointed out that the kind of catalysis involved in the primary genetic process was fundamentally different, in specific ways, from that occurring, e.g., in enzyme systems. The present work demonstrates that, if the information-bearing objects of the general theory are identified with molecules of DNA, and the primary gene products are considered to be RNA of the “messenger” variety, then the predictions of the general theory can be compared with experimental data from various recently isolated polymerase systems, which appear to “copy” a sequence of nucleotides from DNA into RNAin vitro, and with certainin vivo microbial systems. It is found that these data provide detailed support for the conclusions drawn from the general theory. However, it is emphasized that the identification of the information-bearing objects and primary gene products as DNA and RNA respectively, which allows us to compare the theory with the cited data, is by no means the only identification which can be made; i.e., other interpretations of the general theory are certainly not precluded. This research was supported by the United States Air Force through the Air Force Office of Scientific Research of the Air Research and Development Command, under Grant No. AF-AFOSR-9-63.     

Influence of glucose concentration on the physiology and lipid composition of some yeasts

The fatty acid contents of the “Crabtree-positive” yeastsSaccharomyces cerevisiae, S. carlsbergensis andS. delbrueckii decreased with increasing concentrations of glucose in the medium. These lower values were due to a lower content of sterol esters and phosphatides inS. cerevisiae, and of sterol esters inS. carlsbergensis. In contrast the fatty acid contents of the Crabtree-negativeS. fragilis, Schwanniomyces occidentalis andCandida utilis increased with increasing concentrations of glucose and inCandida utilis this was due almost entirely to a higher content of triglycerides. This work was supported in part by grant B/SR/5780 from the Science Research Council. We are grateful to the Brewer's Society for a Research Scholarship to Mr. B. Johnson. We thank Mr. A. Bradley for competent technical assistance.     

Biological characteristics ofSalmonella weltevreden typing phages

The important biological characteristics ofSalmonella weltevreden (3,10∶r∶z₆) typing phages were studied. On the basis of these, the phages could be classified into three groups: phages Φ I and Φ II, phages Φ III, Φ IV and Φ VI, and phage Φ V. Part of the work was done at the National Salmonella and Escherichia Centre, Central Research Institute, Kasauli, India.     

An artificial hysteresis binary neuron: a model suppressing the oscillatory behaviors of neural dynamics

A hysteresis binary McCulloch-Pitts neuron model is proposed in order to suppress the complicated oscillatory behaviors of neural dynamics. The artificial hysteresis binary neural network is used for scheduling time-multiplex crossbar switches in order to demonstrate the effects of hysteresis. Time-multiplex crossbar switching systems must control traffic on demand such that packet blocking probability and packet waiting time are minimized. The system using n×n processing elements solves an n×n crossbar-control problem with O(1) time, while the best existing parallel algorithm requires O(n) time. The hysteresis binary neural network maximizes the throughput of packets through a crossbar switch. The solution quality of our system does not degrade with the problem size.     

A rapid and specific enrichment procedure forHyphomicrobium spp.

An enrichment procedure for the isolation of stalked bacteria of the genusHyphomicrobium is described. The method is based on the use of an organic C₁ compound as carbon and energy source for growth together with anaerobic incubation in the presence of nitrate as an electron acceptor. Optimal conditions for the growth of a number ofHyphomicrobium isolates have been investigated. Applying these conditions,Hyphomicrobium spp. have been enriched from a wide range of natural habitats within 1–2 weeks. This work was supported by a Grant from the Medical Research Fund, University of Sheffield, England, to M.M.A.     

DNA amounts in the nuclei ofParamecium aurelia andTetrahymena pyriformis

DNA amounts have been determined in the micronuclei and macronuclei of 8 strains ofParamecium aurelia and 6 strains ofTetrahymena pyriformis. In the case ofTetrahymena a distribution of values for the amount of DNA in the macronuclei of all the strains was observed but the lowest values were approximately the same, viz. 1.17×10⁻¹¹ g. There are two groups of strains in relation to micronuclear DNA values ofTetrahymena, one giving an average of 0.36×10⁻¹² g and the other 0.815×10⁻¹² g. The ratio of MIC/MAC DNA varies in the two groups.Paramecium again has a range of macronuclear values within each stock—lowest value 2.51×10⁻¹⁰ g—and the micronuclear values are similar in all stocks—approximately 0.613×10⁻¹² g. The ratio of MIC/MAC DNA is similar in each stock.—The haploid genome values calculated from these data show excellent agreement with the values obtained by DNA renaturation studies. Supported by a Research Grant B/SR/8276 from the Science Research Council. The Vickers densitometer was purchased with a grant from the Medical Research Council.     

International Conference on “Photosynthesis Research for Sustainability-2011”, July 24–30, 2011, Baku,Azerbaijan

In this brief report, we provide a perspective on an international conference “Photosynthesis Research for Sustainability-2011”, held in Baku, Azerbaijan, during July 24–30, 2011 (). At this conference, awards were given to nine young investigators; they are recognized in this Report. We have also included here some photographs to show the pleasant ambiance at this conference. (See and for more photographs taken by the authors as well as by others.) We invite the readers to the next conference on “Photosynthesis Research for Sustainability-2013” to be held in May or June 2013, in Baku, Azerbaijan. Information will be posted at: .     

High constitutive peroxidase activity and constitutive thermotolerance in <Emphasis Type="Italic">Neurospora crassa</Emphasis>

 During the isolation of mutations in the heat-inducible hsp70-1 gene of Neurospora crassa by RIP (repeat-induced point mutations), several transformants were generated by electroporation of conidia with a plasmid harboring an incomplete copy of this gene. One isolate, designated E-45, containing ectopically integrated hsp70-1 DNA, exhibited a slow growth rate, low-temperature sensitivity, constitutive thermotolerance (without prior heat shock), and high constitutive peroxidase activity. The constitutive form of peroxidase (CP) was distinguishable from the heat-inducible form (HIP) by immunoinactivation employing polyclonal antiserum against the latter enzyme and by electrophoretic resolution in nondenaturing polyacrylamide gels. This enzyme was purified to near homogeneity and some of its properties examined. The relative molecular mass of native CP was in the range of 118–136 kDa, as estimated by gel filtration analysis on size exclusion matrices, whereas SDS-PAGE analysis yielded a size of ∼37 kDa for the polypeptide. Substrate saturation kinetics studies were conducted using ABTS [2,2′-azino-bis (3-ethylbenzthiazole-6-sulfonic acid)] and H₂O₂ as substrates: K _m, V _max, and K _cat values for H₂O₂ were ∼22 μM, ∼447 nmol mg⁻¹, and 0.33 s⁻¹, respectively, and those for ABTS were ∼55 μM, ∼453 nmol mg⁻¹, and 0.3 s⁻¹, respectively. Guaiacol was not used as a substrate by this enzyme. CP peroxidase was shown to be a heme-containing enzyme, stable at temperatures up to 58°C. Received: August 5, 2002 / Accepted: January 22, 2003 Acknowledgments This work was supported by an operating grant from the Natural Sciences and Engineering Research Council (NSERC) of Canada (to M.K.). The financial support provided to A. M. in the form of a graduate studentship award by the AHFMR (Alberta Heritage Foundation for Medical Research) and of a graduate teaching assistantship to A. S. by the Department of Biological Sciences, University of Calgary, is gratefully acknowledged. Correspondence to:M. Kapoor     

Growth history and migration of the threespine stickleback <Emphasis Type="Italic">Gasterosteus aculeatus</Emphasis> in Otsuchi Bay,northeastern Japan

 Both growth and migratory history of the Pacific Ocean forms of the threespine stickleback Gasterosteus aculeatus collected in Otsuchi Bay, northeastern Japan, were examined using otolith microstructure and analysis of strontium (Sr) and calcium (Ca) concentrations with wavelength dispersive X-ray spectrometry by an electron microprobe. Age of the juveniles (21.6–25.9 mm in total length) examined ranged from 101 to 128 days (115 ± 8.5 days; mean ± SD), hatching being estimated as having occurred between March and April 2001. The Sr : Ca ratios in the otoliths changed with both ontogenic development and salinity of the habitat. The otolith Sr : Ca ratios increased gradually from 4.1 × 10⁻³ around the core to 7.5 × 10⁻³ around the edge of the otolith. The fluctuation pattern of otolith Sr : Ca ratios was different from those observed in both freshwater resident and anadromous forms in previous studies. These results suggested that the fish sampled spend their lives in the estuarine and sea environment without freshwater life after hatching. Received: June 5, 2002 / Revised: September 11, 2002 / Accepted: September 24, 2002 Acknowledgments We thank Mr. K. Morita and crews of the Otsuchi Marine Research Center, Ocean Research Institute, The University of Tokyo for their assistance in collecting specimens. This work was supported in part by Grant-in-Aid No. 13760138 from the Ministry of Education, Culture, Sports, Science and Technology, Japan. Correspondence to:Takaomi Arai     

The effect of jasmonic acid on the accumulation of ABA,proline and spermidine and its influence on membrane injury under water deficit in two barley genotypes

Seedlings of two barley genotypes (‘Maresi’ and wild form of Hordeum spontaneum) were treated with jasmonic acid (JA 5 μM and 15 μM) for 24 h, and then subjected to water stress (PEG 6000 solution of − 1.5 MPa). JA caused an increase in the content of ABA but not in that of proline and spermidine in the two studied genotypes. The effect of the treatment did not depend on the applied JA concentration. The pre-stress treatment with JA changed plant response to water deficit with regard to membrane injury. Treatment with a lower JA concentration (5 μM) caused a substantial reduction of the stress-induced membrane damage in the both genotypes. A higher JA concentration (15 μM) caused the reduction of membrane injury only in H. spontaneum and was ineffective in ‘Maresi’. JA had no influence on the leaf water status in water-stressed plants. A possible role of JA in leaf ABA accumulation and alleviation of cell membrane injury under water deficit is discussed. The work was partly supported by the Polish Committee For Scientific Research, grant No 5 PO6A 036 18     

Occurrence of sea eels of <Emphasis Type="Italic">Anguilla japonica</Emphasis> along the Sanriku Coast of Japan

 The age and migratory history of the Japanese eel, Anguilla japonica, collected along the Sanriku Coast of Japan, were examined using otolith microstructure and analysis of strontium (Sr) and calcium (Ca) concentrations. The mean Sr : Ca ratios from the elver mark to the otolith edge indicated that there were eels with several general categories of migratory history, including sea eels that never entered freshwater and others which had entered freshwater for brief periods but returned to the estuary or bay. This first evidence of the occurrence of sea eels in this northern area indicates that Japanese eels of the Sanriku Coast do not necessarily migrate into freshwater rivers. Received: May 15, 2002 / Revised: August 4, 2002 / Accepted: August 15, 2002 Acknowledgments We thank Messrs. S. Yamane and K. Morita, and crews of the Otsuchi Marine Research Center, Ocean Research Institute, The University of Tokyo, for their assistance in collecting the eels. This work was supported in part by Grant-in-Aid No. 13760138 from the Ministry of Education, Culture, Sports, Science and Technology, Japan. Correspondence to:Takaomi Arai     

Formal modeling with multistate neurones and multidimensional synapses

Multistate neurones, a generalization of the popular McCulloch-Pitts binary neurones, are described; they are intended to model the fact that neurones may be in several different states of activity, while McCulloch-Pitts neurones model two states only: active or inactive. We show that as a consequence, multidimensional synapses are necessary to describe the dynamics of the model. As an illustration, we show how to derive the parameters of formal multistate neurones and their associated multidimensional synapses from simulations involving Hodgkin-Huxley neurones. Our approach opens the way to solve in a more biologically plausible way, two problems that were addressed previously: (1) the resolution of 'inverse problems', i.e. the construction of formal networks, whose dynamics follows a pre-defined spatio-temporal binary sequence, (2) the generation of spatio-temporal patterns that reproduce exactly the 'code' extracted from experimental recordings (olfactory codes at the glomerular level).     

Rule-dynamical generalization of McCulloch-Pitts neuron networks

A new aspect for neuronal networks is presented. The aspect is based on the concept of ruledynamics which was originally proposed by one of the authors, Aizawa. The concept of ruledynamics were modeled on the two states cellular automata of neighborhood-three (CA(2/3)). A brief review of ruledynamics is also presented, because most publications of the authors so far have been in Japanese. Our concise assertion in the present paper is that a neuronal network realizes a kind of ruledynamics. This assertion is a speculation on the comparison of McCulloch-Pitts neuron networks with ruledynamics on CA(2/3). A trial is originally shown to demonstrate that a McCulloch-Pitts neuron network can be imitated by an extended version of ruledynamics on CA(2/3).     

An in vitro model of acetaldehyde metabolism by rodent conceptuses

Summary A culture model is described for the study of acetaldehyde (A_cH) metabolism by explanted postimplantation rat and mouse conceptuses. The ability of 12-d rat and 10-d mouse embryos to metabolise A_cH was demonstrated. The elimination rate for the 12-d rat conceptus using an initial A_cH concentration of 1 mM in the medium was found to be 1.8 nmol/mg per minute. When the conceptus was divided into embryonic and extraembryonic tissue, the rates were 1.6 and 2.2 nmol/mg per minute, respectively. When the A_cH concentration was reduced to 50 μM the rate was 0.095 nmol/mg per minute. The results provide further evidence for a functional barrier that prevents A_cH entry to the embryo. A comparative experiment using CBA/beige mouse conceptuses showed that A_cH elimination characteristics may be qualitatively similar to those in rat embryos, but that the estimated elimination rate of 0.8 nmol/mg per minute was less than half that of the rat. Thus the “metabolic barrier” may be less efficient in the mouse. This may be important in view of the greater sensitivity of the mouse to ethanol embryotoxicity. The work was supported by the King Edward Memorial Hospital Research Foundation and the Raine Research Foundation.     

Existence of traveling waves for integral recursions with nonmonotone growth functions

A class of integral recursion models for the growth and spread of a synchronized single-species population is studied. It is well known that if there is no overcompensation in the fecundity function, the recursion has an asymptotic spreading speed c*, and that this speed can be characterized as the speed of the slowest non-constant traveling wave solution. A class of integral recursions with overcompensation which still have asymptotic spreading speeds can be found by using the ideas introduced by Thieme (J Reine Angew Math 306:94–121, 1979) for the study of space-time integral equation models for epidemics. The present work gives a large subclass of these models with overcompensation for which the spreading speed can still be characterized as the slowest speed of a non-constant traveling wave. To illustrate our results, we numerically simulate a series of traveling waves. The simulations indicate that, depending on the properties of the fecundity function, the tails of the waves may approach the carrying capacity monotonically, may approach the carrying capacity in an oscillatory manner, or may oscillate continually about the carrying capacity, with its values bounded above and below by computable positive numbers. B. Li’s research was partially supported by the National Science Foundation under Grant DMS-616445. M. A. Lewis research was supported by “The Canada Research Chairs program,” and a grant from the Natural Sciences and Engineering Research Council of Canada.     

Evidence for the presence of thyroid stimulating hormone, thyroglobulin and their receptors in Eisenia fetida: a multilevel hormonal interface between the nervous system and the peripheral tissues

The present study describes the localization and distribution of thyroid-stimulating hormone (TSH), thyroglobulin (TGB) and their receptors in Eisenia fetida (Annelida, Oligochaeta) as revealed by immunohistological methods. Immunopositive neuronal and non-neuronal cells are present in both the central nervous system and some peripheral organs (e.g. foregut and coelomocytes). TSH- and TGB-immunopositive neurons in the various ganglia of the central nervous system are differentailly distributed. Most of the immunoreactive cells are found in the suboesophageal ganglion. The stained cells also differ in their shapes (round, oval, pear-shaped) and sizes (small, 12–25 μm; medium, 20–35 μm; large, 30–50 μm). In all ganglia of the central nervous system, TSH-positive neurons additionally show gamma aminobutyric acid (GABA) immunopositivity. Non-neuronal cells also take part in hormone secretion and transport. Elongated TSH-positive cells have been detected in the capsule of the central ganglia and bear granules or vacuoles in areas lacking neurons. Many of capillaries show immunoreactivity for all four tested antibodies in the entire central nervous system and foregut. Among the coelomocytes, granulocytes and eleocytes stain for TSH and its receptor and for TGB but not for thyroid hormone receptor. Most of the granulocytes are large (25–50 μm) but a population of small cells (10–25 μm) are also immunoreactive. None of the coelomocytes stain for GABA. We therefore suggest that the members of this hormone system can modify both metabolism and immune functions in Eisenia. Coelomocytes might be able to secrete, transport and eliminate hormones in this system.This work was supported by the MTA-PTE Adaptation Biology Research Group and National Research and Developmental Fund (NKP 1/048/2001). M.W. is in receipt of a János Bolyai Scholarship.