Insect Biochemistry and Function

Size: px

Start display at page:

Download "Insect Biochemistry and Function"

Leonard Griffin
5 years ago
Views:

1 Insect Biochemistry and Function

2 Insect Biochemistry and Function Edited by 0.1. CANDY Lecturer in Biochemistry University of Birmingham and B. A. KILBY Reader in Biochemistry University of Leeds CHAPMAN AND HALL LONDON

3 First published 1975 by Chapman and Hall Ltd 11 New Fetter Lane, London EC4P 4EE First published as a Science Paperback Chapman and Hall Ltd Typeset by Preface Limited, Salisbury, Wilts ISBN-13: e-isbn-13: DOl: / This title is available in both hardbound and paperback editions. The paperback edition is sold subject to the condition that it shall not, by way of trade or otherwise, be lent, re-sold, hired out, or otherwise circulated without the publisher's prior consent in any form of binding or cover other than that in which it is published and without a similar condition including this condition being imposed on the subsequent purchaser All rights reserved. No part of this book may be reprinted, or reproduced or utilized in any form or by any electronic, mechanical or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publisher Distributed in the U.S.A. by Halsted Press, a Division of John Wiley & Sons, Inc., New York

4 Contributors E. Bailey Dept: of Biochemistry, The University, Sheffield, Yorkshire. D. G. Cochran Dept: of Entomology, Virginia Polytechnic, Institute and State University, Virginia, U.S.A. G. G. Lunt Dept: of Biochemistry, School of Biological Sciences, University of Bath, Somerset. B. Sacktor Gerontology Research Center, National Institute of Child Health and Human Development, National Institute of Health, Baltimore, U.S.A.

5 Contents Preface Chapter 1. Biochemistry ofinsect Flight. B. SACKTOR Part 1 - Utilization of Fuels by Muscle In trod uction Pathways for the Utilization of Carbohydrates, Amino acids Page xi and Fats in Flight Muscle 4 Physiological aspects of the bioenergetics of flight 4 Glycogenolysis 5 Utilization of trehalose 20 Glyco!ysis 22 Glycolytic-mitochondrial interactions 29 Auxiliary glycolytic reactions 33 Oxidation of the end-products of glycolysis and the permeability of mitochondria to metabolic intermediates 35 Utilization of amino acids 40 Oxidation of fat 45 The Control of Flight Muscle Mitochondrial Metabolism 49 Morphological and biochemical organization of flight muscle mitochondria 50 Oxidative phosphorylation 56 Control of the mitochondrial oxidation of a-glycerol-p 61 Control of the mitochondrial oxidation of proline 63 Control of the mitochondrial oxidation of pyruvate and the citric acid cycle vii

6 viii INSECT BIOCHEMISTRY AND FUNCTION Mitochondrial ion movements and the special role of Ca2+ in the regulation of flight muscle metabolism 70 The oxidation-reduction state of the respiratory components in mitochondria and the control of me tabolism 76 References 81 Chapter 2. Biochemistry of Insect Flight. E. BAILEY Part 2 - Fuel Supply 89 Introduction 91 The Nature of Respiratory Fuels 92 Stores of Respiratory Fuels 93 Lipids and their Metabolism 94 Tissue content of lipids 96 Absorption of dietary lipids and incorporation into fat body lipids 107 Lipid degradation by fat body 110 Biosynthesis of lipids 117 Lipid release from the fat body 137 Carbohydrates and their Metabolism 146 Tissue content of carbohydrates 146 Utilization of carbohydrate reserves during flight 148 Metabolism of sugars other than glucose 150 Glycogen biosynthesis 152 Trehalose biosynthesis 154 Carbohydrate synthesis from non-carbohydrate precursors 157 Glycogen breakdown 159 Hormonal control of carbohydrate metabolism 161 The Supply of Amino Acid Fuels for Flight 164 Conclusion 166 References 167 Chapter 3. Excretion in Insects. D. G. COCHRAN 177 Introduction 179 Excretion Associated with the Ma1pighian Tubule-Rectum System 181 Ions, water and active transport 182 Uric acid 191 Ammonia 215 Urea 223 Amino acids 228

7 CONThNTS ix Tryptophan derivatives 232 Pteridines 243 Other nitrogenous products 252 Carbohydrates 254 Miscellaneous excretory products 255 Xenobiotics 256 Minor Excretory Systems 258 Labial glands 259 Pericardial and other cells 260 Utriculi majores 261 The gut 262 Concluding Remarks 264 References 265 Addendum 282 Chapter 4. Synaptic Transmission in Insects. G. G. LUNT 283 Introduction 285 General Outline of the Insect Nervous System 285 Chemical Transmitters in the Central Nervous System 288 Acetylcholine 288 Acetylcholine receptors 289 Glutamic acid and 'Y-amino butyric acid (GABA) 290 Biogenic amines 293 Chemical Transmitters at the Neuromuscular Junction 294 Glutamic acid 294 Glutamate receptor 297 Enzymes associated with the glutamate system 298 'Y-Amino butyric acid (GABA) 300 Biogenic amines 30 I Summary 301 References 302 Addendum 305 Index 307

8 Preface There has been a considerable upsurge in interest in insect biochemistry and physiology in recent years and this has been reflected in a notable expansion in the number of original papers in this field. Whereas insect physiology has tended to receive ample attention from reviewers, the same has not always been true for the more biochemical aspects of insect research. This book is a venture to help redress the balance. No attempt has been made to cover all aspects of insect biochemistry, but rather a few topics have been selected which seemed to us to merit a review at the present time. One reason for this increased interest in insect biochemistry is perhaps the growing realization that insects can be very useful organisms to act as model systems for the experimental study of general biochemical principles. One remembers, for instance, that Keilin's perceptive observations on the flight muscles of living bees and wax moths led to his discovery of the cytochromes. The fundamental unity of biochemistry has long been accepted as a dogma by the faithful and the insect kingdom provides no exception to it. The main biochemical processes in insects are being revealed as essentially the same as in other life forms but, as so often found in comparative biochemistry, there are interesting variations on the central theme. Often by choosing an appropriate insect species, one can find an example of a particular biochemical mechanism which has been developed or modified to a considerable extent and the xi

9 xii INSECT BIOCHEMISTRY AND FUNCTION study of such a system may be most informative about general biochemical mechanisms. It is this correlation between biochemical specialization and physiological function that can make the subject so fascinating. A good example of such a process is insect flight, which clearly illustrates the numerous biochemical adaptations that can occur concomitant with a specific function. A discussion of this subject has been given particular attention in the first half of this book. Another reason for the increased activity in insect biochemistry is an economic one. The production of insecticides is now a major industry and one in which constant research for new products is essential. Insects soon develop resistant strains under selection pressure from the use of a particular insecticide and the development of new ones is frequently required. One would hope that an increased knowledge of insect biochemistry and physiology would facilitate a rational approach to the development of new lethal agents which interfere with the normal life processes in insects. The aim, however, must be selective toxicity in which the agent is insectspecific while man, other animals and if possible, beneficial insects are unaffected and unharmed. This selectivity would not be expected if the insecticide interferes with some fundamental process common to most organisms as happens, for instance, with the use of cyanide to inhibit cytochrome oxidase. Rather, the ultimate target of the insecticide must be some biochemical or physiological adaption or modification which is essential for the insect but absent or unimportant in the species which one does not wish to harm. A detailed knowledge of biochemical differences between insects and other life forms could have great potential and importance and we hope that this book may perhaps serve to stimulate further interest and research in these areas, and eventually assist in the rational design of selective insecticides. D. 1. C. October 1974 B. A. K.

Introduction to Virology

Introduction to Virology Introduction to Virology K. M. SMITH C.B.E., D.Se., Ph.D., F.R.S. Formerly Director, Virus Research Unit, Agricultural Council, Cambridge Chapter 9, The replication of viruses