Natural Computing Series Series Editors: G. Rozenberg Th. Biick A.E. Eiben J.N. Kok H.P. Spaink Leiden Center for Natural Computing s. Advisory Board: Amari G. Brassard K.A. De Jong C.C.A.M. Gielen T. Head L. Kari L. Landweber T. Martinetz Z. Michalewicz M.C. Mozer E. Oja G. Păun J. Reif H. Rubin A. Salomaa M. Schoenauer H.-P. Schwefel C. Torras D. Whitley E. Winfree J.M. Zurada Ro Paton t oH o Bolouri oM o Holcombe JoHo Parish oR o Tateson (Edso) CoDtputation in Cells and Tissues Perspectives and Tools of Thought With 134 Figures ~ Springer Editors J. Howard Parish Ray Paton' School of Biochemestry and Molecular Biology Hamid Bolouri University of Leeds Institute for Systems Biology Leeds LS2 9JT, UK Seattle, \VA 98103, USA [email protected] [email protected] Series Editors Mike Holcombe G. Rozenberg (Managing Editor) Department of Computer Science [email protected] University of Sheffield Th. Băck, J.N. Kok, H.P. Spaink Sheffield SI 4DP, UK [email protected] Leiden Center for Natural Computing Leiden University Richard Tateson Niels Bohrweg 1 Future Technologies Group 2333 CA Leiden, The Netherlands Intelligent Systems Lab A.E.Eiben BTexact Technologies Vrije Universiteit Amsterdam Ipswich IPS 3RE, UK The Netherlands richard. [email protected] Library of Congress Control N umber: 2004042949 ACM Computing Classification (1998): EO, 1.1-2, 1.6, J.3 ISBN 978-3-642-05569-0 ISBN 978-3-662-06369-9 (eBook) DOI 10.1007/978-3-662-06369-9 This work is subject to copyright. Ali rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting. reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag Berlin Heidelberg GmbH. Violations are liable for prosecution under the German Copyright Law. springeronline.com © Springer-Verlag Berlin Heidelberg 2004 Originally published by Springer-Verlag Berlin Heidelberg New York in 2004 Softcover reprint of the hardcover 1s t edition 2004 The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Cover Design: KiinkelLopka, Werbeagentur, Heidelberg Typesetting: by the Authors Production: LE-TEX Jelonek, Schmidt & Vockler GbR, Leipzig Printed on acid-free paper 4513142/YL - 543210 It is with great sadness that we have to report the sudden death of Dr. Ray Paton, the principal editor of this volume, just before we went to press. Ray worked tire lessly to bring this book to Jruition and it stands as a rich testament to his inspira tionalleadership and vision in the field. Alt of the other editors wish to record our great gratitude to Ray, who was not only an outstanding scientist but also agreat friend and colleague. We hope that this book will, in some way, be looked upon as a memorial to Ray's pioneering work in biologically inspired computing and computational biology. Preface The field of biologically inspired computation has coexisted with mainstream computing since the 1930s, and the pioneers in this area include Warren McCulloch, Walter Pitts, Robert Rosen, Otto Schmitt, Alan Turing, John von Neumann and Norbert Wiener. Ideas arising out of studies of biology have permeated algorithmics, automata theory, artificial intelligence, graphics, information systems and software design. Within this context, the biomolecular, cellular and tissue levels of biological organisation have had a considerable inspirational impact on the development of computational ideas. Such innovations include neural computing, systolic arrays, genetic and immune algorithms, cellular automata, artificial tissues, DNA computing and protein memories. With the rapid growth in biological knowledge there remains a vast source of ideas yet to be tapped. This includes developments associated with biomolecular, genomic, enzymic, metabolic, signalling and developmental systems and the various impacts on distributed, adaptive, hybrid and emergent computation. This multidisciplinary book brings together a collection of chapters by biologists, computer scientists, engineers and mathematicians who were drawn together to examine the ways in which the interdisciplinary displacement of concepts and ideas could develop new insights into emerging computing paradigms. Funded by the UK Engineering and Physical Sciences Research Council (EPSRC), the CytoCom Network formally met on five occasions to examine and discuss common issues in biology and computing that could be exploited to develop emerging models of computation. Many issues were raised concemed with modelling, robustness, emergence, adaptability, evolvability and networks, and many tools of thinking and ways of addressing problems were introduced and discussed. This book seeks to highlight many aspects of this growing area of study and will allow the reader to explore a breadth of ideas. Ray Paton' Biocomputing and Computational Biology Group Department of Computer Science May 2004 The University of Liverpool, UK Contents CytoComputational Systems - Perspectives and Tools of Thought •••••••••••••••••• 1 R. C. Paton 1 Plan of the Book ....................................................................................... 2 2 History of the CytoComputational Systems Project ................................. 6 Cells in Telecommunications •...•..••.....•••••.•••••••...••••••..•••.••••••.••.•.••••••••••••.••••••••••••• 9 R. Tateson 1 Introduction ............................................................................................... 9 2 Telecommunication Problems ................................................................ 11 3 Features of Cells ..................................................................................... 12 3.1 Evolutionary History ....................................................................... 12 3.2 Division History .............................................................................. 12 3.3 'Life History' ................................................................................... 12 3.4 Dynamic, Metabolic ........................................................................ 13 3.5 Autonomous .................................................................................... 13 3.6 Emergent Control ............................................................................ 14 4 Cell-based Solutions for Telecommunications Problems ....................... 14 4.1 Fruitflies and Mobile Phones ........................................................... 15 4.2 Design by Morphogenesis ............................................................... 17 4.3 CellSim ............................................................................................ 20 5 Conclusion .............................................................................................. 25 References ........................................................................................................ 25 Symbiogenesis as a Machine Leaming Mechanism. ......................................... 27 L. Bull, A. Tomlinson 1 Introduction ............................................................................................. 27 2 Simulated Symbiogenesis ....................................................................... 28 2.1 The NKCS Model ............................................................................ 28 2.2 Genetic Algorithm Simulation ......................................................... 29 2.3 Results ............................................................................................. 31 2.4 Discussion. ....................................................................................... 33 3 Symbiogenesis in Machine Leaming ...................................................... 36 3.1 ZCS: A Simple Leaming Classifier System .................................... 36 3.2 Symbiogenesis in a Leaming Classifier System .............................. 38 3.3 Woods 1 ........................................................................................... 40 3.4 Symbiont Encapsulation .................................................................. 41 3.5 System Evaluation in Markov and non-Markov Environments ..... .44 4 Conclusion .............................................................................................. 48 References ........................................................................................................ 49 An Overview of Artificial Immune Systems ...................................................... 51 J. Timmis et al. 1 Introduction ............................................................................................. 51 X Contents 2 The Immune System: Metaphorically Speaking ..................................... 52 3 The Vertebrate Immune System ............................................................. 54 3.1 Primary and Secondary Immune Responses .................................... 55 3.2 B-cells and Antibodies .................................................................... 55 3.3 Immune Memory ............................................................................. 56 3.4 Repertoire and Shape Space ............................................................ 59 3.5 Learning within the Immune Network ............................................ 59 3.6 The Clonal Selection Principle ........................................................ 62 3.7 Self/Non-Self Discrimination .......................................................... 63 3.7.1 Negative Selection ........................................................................ 63 4 From Natural to Artificial Immune Systems .......................................... 64 4.1 Summary ......................................................................................... 65 5 The Immune System Metaphor ............................................................... 66 5.1 A Framework for AIS ...................................................................... 66 5.2 Machine Learning ............................................................................ 68 5.3 Robotics ........................................................................................... 76 5.4 Fault Diagnosis and Tolerance ........................................................ 78 5.5 Optimisation .................................................................................... 79 5.6 Scheduling ....................................................................................... 81 5.7 Computer Security ........................................................................... 82 6 Summary ................................................................................................. 83 7 Comments on the Future for AIS ............................................................ 84 References ....................................................................................................... 86 Embryonics and Immunotronics: Biologically Inspired Computer Science Systems ................................................................................ 93 A. Tyrrell 1 Introduction ............................................................................................ 93 2 An Overview of Embryonics .................................................................. 95 2.1 Multicellular Organization .............................................................. 95 2.2 Cellu1ar Division ............................................................................. 95 2.3 Cellular differentiation .................................................................... 95 3 The Organism's Features: Multicellular Organization, Cellular Differentiation, and Cellular Division .................................................... 97 4 Architecture of the Cell .......................................................................... 98 4.1 Memory ........................................................................................... 99 4.2 Address Generator ......................................................................... 100 4.3 Logic Block ................................................................................... 100 4.4 Inputloutput Router ....................................................................... 101 4.5 Error Detection and Error Handling .............................................. 102 5 Examples .............................................................................................. 103 6 Immunotronics ...................................................................................... 105 7 Reliability Engineering ......................................................................... 106 8 The Reliable Human Body ................................................................... 107 9 Bio-Inspired Fault Tolerance ................................................................ 107 10 Artificial Immune Systems ................................................................... 108 11 Domain Mapping .................................................................................. 109 Contents XI 12 Choice of Algorithm ............................................................................. 109 13 Architecture of the Hardware Immunisation Suite ............................... 109 14 Embryonics and Immunotronic Architecture ........................................ l12 15 Conclusion ............................................................................................ 112 References ...................................................................................................... 114 Biomedical Applications of Micro and Nano Technologies ........................... 117 C. J. McNeil, K. 1. Snowdon 1 Background ........................................................................................... 117 2 Biomedical Applications of Nanotechnology ....................................... 118 3 Developing a Multidiscip1inary Base - The NANOMED Network ..... 120 4 Initial Challenges to NANOMED Problems ......................................... 122 5 Concluding Remarks ............................................................................. 123 References ...................................................................................................... 124 Macromolecules, Genomes and Ourselves ...................................................... 125 S. Nagl et al. 1 Preamble ............................................................................................... 125 2 Macromolecules: Properties and Classification .................................... 126 2.1 Architecture, Form and Function ................................................... 126 2.2 Data Resources .............................................................................. 129 2.3 Protein Classification ..................................................................... 129 2.4 Protein Signatures .......................................................................... 130 3 Models and Metaphors .......................................................................... 131 3.1 Proteins as Machines ..................................................................... 131 3.2 lnformation Processing by Proteins ............................................... 132 4 Modelling of Complex Cellular Systems for Post-genomic Biomedicine ............................................................. 134 4.1 Introduction: A Systems View of Life ........................................... 134 4.2 Complexity and Post-genomic Biomedicine ................................. 139 4.3 New Models for Biomedicine: Ethical Implications of Model Choice ............................................................................................ 140 4.4 Models as Metaphoric Constructions .............................................. 142 5 Conclusions ........................................................................................... 144 References ...................................................................................................... 145 Models of Genetic Regulatory Networks ......................................................... 149 H. Bo10uri, M. Schilstra 1 What are Genetic Regulatory Networks? ............................................. 149 2 What is a Gene? .................................................................................... 150 3 Regulation of Single Genes .................................................................. 151 4 Differences in Gene Regulation Between Organisms ........................... 151 5 Modeling GRNs .................................................................................... 152 6 Some GRN Models to Date .................................................................. 153 7 GRN Simulators .................................................................................... 155 8 Uses ofGRNs Beyond Biology ............................................................ 156 References ...................................................................................................... 156 XII Contents A Model of Bacterial Adaptability Based on Multiple Scales of Interaction: COSMIC .................•...•••.••••••••••.•.•.•••.............................•.....•... 161 R. Gregory et al. 1 Introduction .......................................................................................... 162 2 Biology .................................................................................................. 163 2.1 DNA, RNA and Proteins .............................................................. 163 2.2 Transcription ................................................................................ 164 2.3 Protein Structure ........................................................................... 165 2.4 Optional Transcription .................................................................. 166 2.5 lac Operon .................................................................................... 166 2.6 trp Operon .................................................................................... 167 2.7 An E. ecoli Environment .............................................................. 168 3 The Genome and the Proteome ............................................................ 169 4 Model ................................................................................................... 170 5 Implementation ..................................................................................... 173 6 Results .................................................................................................. 173 6.1 Environmental Macroscopic View ............................................... 173 6.2 CeH Lineage ................................................................................. 175 6.3 Gene Expression ........................................................................... 176 6.4 Network Graphs ........................................................................... 178 6.5 CeH Statistics ................................................................................ 178 7 Discussion ............................................................................................ 182 References .................................................................................................... 183 Stochastic Computations in Neurons and Neural Networks ......................... 185 J. Feng 1 Abstract ................................................................................................ 185 2 The Integrate-and-File Model and Its Inputs ........................................ 189 3 Theoretical Results ............................................................................... 191 3.1 Behaviour of a.(A)"2c,r) ............................................................... 192 3.2 Input-Output Relationship ........................................................... 195 4 Informax Principle ................................................................................ 197 4.1 The IF Model Redefined .............................................................. 197 5 Leaming Rule ....................................................................................... 198 6 Numerical Results ................................................................................ 202 6.1 Supervised Leaming ..................................................................... 202 6.2 Unsupervised Leaming ................................................................. 203 6.3 Signal Separations ........................................................................ 204 7 Discussion ............................................................................................ 205 References .................................................................................................... 209 Spatial Patterning in Explicitly Cellular Environments: Activity-Regulated Juxtacrine Signalling ••.•...................................................• 211 N. Monk 1 Introduction .......................................................................................... 211 2 Biological Setting ................................................................................. 212 3 Mathematical Models of Juxtacrine Signalling .................................... 213 Contents XIII 4 Pattern Fonnation ................................................................................. 215 4.1 Lateral Inhibition and Spacing Patterns ......................................... 215 4.2 Gradients and Travelling Fronts .................................................... 218 4.3 More Complex Spatial Patterns ..................................................... 220 5 Further Developments ........................................................................... 223 References ...................................................................................................... 223 Modelling the GH Release System ................................................................... 227 D. J. MacGregor et. al. 1 Introduction ........................................................................................... 227 2 Research Background ........................................................................... 227 3 GH Research ......................................................................................... 228 3.1 Experimental Approach ................................................................. 229 3.2 Anatomical Results ........................................................................ 230 3.3 Electrophysiological Results ......................................................... 231 3.4 Behavioural Results ....................................................................... 231 4 Creating the System .............................................................................. 233 4.1 Simplifications ............................................................................... 235 5 Making the Experimental Model .......................................................... 235 5.1 Storage V ariables ........................................................................... 236 5.2 Input Protocols ............................................................................... 236 6 The Model. ............................................................................................ 237 6.1 The Pituitary Model ....................................................................... 237 6.2 The GH System Model .................................................................. 238 7 Working with the Model ....................................................................... 240 7.1 The Model Parameters ................................................................... 241 7.2 Assessing Perfonnance .................................................................. 241 7.3 Initial Results ................................................................................. 242 7.4 Comparison with real GH release .................................................. 242 7.5 A GHRH-Somatostatin Connection ............................................... 244 7.6 GH-Somatostatin Stimulatory Connection .................................... 245 8 Conc1usions ........................................................................................... 246 References ...................................................................................................... 248 Hierarchies of Machines ..................................................................•.••..•••.••••.•• 251 M. Ho1combe 1 Introduction: Computational Models .................................................... 251 2 More Powerful Machines ..................................................................... 255 2.1 X-machines .................................................................................... 255 2.2 Communicating X-machines [6]. ................................................... 259 2.3 Hybrid Machines ........................................................................... 260 3 Agents and Agent Systems ................................................................... 262 4 Hierarchies of Machines ...................................................................... 264 4.1 Cellular Hierarchies ...................................................................... 264 4.2 Tissue Hierarchies ......................................................................... 266 5 Conc1usions and Further Work ............................................................. 267 References ...................................................................................................... 268