Molecular and Physiological Basis of Nematode Survival

Contents......Page 6
About the Editors......Page 14
Contributors......Page 16
Preface......Page 18
1.1 Introduction......Page 20
1.2.1 The egg......Page 21
1.2.2 Egg packaging......Page 23
1.2.3 Larval stages......Page 24
1.2.4 Adults......Page 25
1.2.5 Dauer forms......Page 26
1.3 Hatching and Dormancy......Page 28
1.4 Behavioural Adaptations......Page 30
1.5.1 Dehydration......Page 32
1.5.2 Rehydration......Page 37
1.6 Implications for Control Options......Page 38
1.7 Conclusions and Future Directions......Page 40
1.8 References......Page 41
2.1 Introduction......Page 47
2.2.1 Cuticle, surface coat and cuticular camouflage......Page 48
2.2.3 Pharyngeal glands – the source of all evil......Page 50
2.3.1 Host invasion......Page 51
2.3.2 Feeding behaviour and structures......Page 54
2.3.4 PAMP-triggered immunity......Page 55
2.3.5 Effector-triggered immunity......Page 56
2.4.1 Defence genes: phytoalexins, pathogenesis-related proteins and protease inhibitors......Page 59
2.4.2 Pathogenesis-related proteins......Page 61
2.4.4 Cell wall fortifications with callose deposits and lignin......Page 62
2.4.5 Hypersensitive response and programmed cell death......Page 63
2.5.1 Detoxification of reactive oxygen species (ROS) and modulation of ROS signalling......Page 67
2.5.2 Modulation of plant hormone balance and secondary metabolism......Page 68
2.5.3 Modulation of lipid-based defences......Page 69
2.5.4 Modulation of calcium signalling......Page 70
2.5.5 Modulation of host protein turnover rate......Page 71
2.5.6 Modulation of host immune receptors......Page 72
2.5.7 Cross-kingdom modulation......Page 73
2.7 Acknowledgements......Page 74
2.8 References......Page 75
3.2 Gastrointestinal-dwelling Nematodes......Page 85
3.2.1 Gastrointestinal nematode infection – chronicity is the norm......Page 86
3.2.2 The immune response to gastrointestinal nematodes – can it be protective?......Page 87
3.2.3 Immunoregulation during chronic infection – a necessary compromise?......Page 89
3.2.4 Trichinella, a gut- and tissue-dwelling nematode that bucks the trend......Page 91
3.3.1 Adaptation to changes in environment......Page 92
3.3.2 Immunomodulation during filarial nematode infection......Page 94
3.3.3 Defined filarial nematode molecules known to modulate the immune system......Page 96
3.4 Conclusions and Future Directions......Page 97
3.5 References......Page 98
4.1 Introduction......Page 105
4.2.2 Pristionchus–beetle interactions......Page 107
4.3 Behaviour and Chemoattraction......Page 109
4.5 From Genetics to Genomics......Page 110
4.5.1 Expansion of detoxification machinery......Page 111
4.5.2 Cellulases and horizontal gene transfer......Page 112
4.5.3 The evolution of parasitism and the role of ‘pre-adaptations’......Page 113
4.6 The Analysis of Pristionchus pacificus Dauer Regulation Provides Inroads for the Study of Parasitism......Page 114
4.7 Conclusions and Future Directions......Page 115
4.9 References......Page 116
5.1 Introduction......Page 118
5.2.1 Environmental signals......Page 120
5.2.2 The chemistry of dauer induction......Page 122
5.2.3 Sensory biology and ecology of dauer signals......Page 124
5.2.4 Dauer signalling and the ecology of the dauer phenomenon......Page 125
5.3 Genetic Variation in Dauer Switching......Page 128
5.4 The Biology of the Dauer Stage......Page 130
5.5.1 Dauer biology and parasitism......Page 132
5.5.2 Dauer molecular biology and parasite evolution......Page 135
5.6 Conclusions and Future Directions......Page 138
5.8 References......Page 139
6.1 Introduction......Page 145
6.2 The Effects of Water Loss on Living Systems......Page 146
6.3 Protein Homeostasis......Page 149
6.4 Membrane Integrity in Anhydrobiotic Nematodes......Page 154
6.5 Oxidative Stress and its Effects during Desiccation and Anhdyrobiosis......Page 157
6.6 Stabilizing Nucleic Acids......Page 159
6.7 Model Nematodes for Anhydrobiosis Studies......Page 160
6.8 Conclusions and Future Directions......Page 162
6.10 References......Page 165
7.1 Introduction......Page 176
7.2 Longevity of Infective Juveniles......Page 178
7.3.1 Stored energy reserves......Page 179
7.3.2 Temperature......Page 180
7.3.3 Desiccation......Page 181
7.4.2 Physiology of temperature tolerance......Page 183
7.4.3 Physiology of desiccation tolerance......Page 186
7.5 Genetic Selection for Temperature and Desiccation Tolerance......Page 188
7.6 Molecular Mechanisms of Desiccation Tolerance......Page 189
7.7.2 Stress tolerance genes......Page 191
7.8 Conclusions and Future Directions......Page 194
7.9 References......Page 195
8.1 Introduction......Page 201
8.2.1 How many strategies?......Page 202
8.2.2 What is the dominant strategy of nematode cold tolerance?......Page 205
8.2.3 Ice nucleation......Page 207
8.3.1 Phenotypic plasticity......Page 208
8.3.3 Heat shock proteins......Page 210
8.3.4 Organic osmolytes......Page 211
8.3.5 Ice-active proteins......Page 212
8.3.6 Other mechanisms of cold tolerance......Page 213
8.4 Linking Mechanisms to Strategies......Page 214
8.4.1 The role of trehalose......Page 215
8.4.2 Stress proteins in cold tolerance......Page 216
8.6 References......Page 217
9.1 Introduction......Page 224
9.2 Molecular Anhydrobiology of Antarctic Nematodes......Page 225
9.3 Stress Response System......Page 227
9.3.1 Constitutively expressed genes......Page 228
9.3.2 Stress-induced genes......Page 231
9.4 Signal Transduction System......Page 235
9.5 Metabolic System......Page 236
9.6 Oxidative Stress Response and Detoxification System......Page 238
9.7 Cryoprotectant......Page 240
9.8 Cross-tolerance and Stress-hardening......Page 242
9.9 Conclusions and Future Directions......Page 244
9.10 Acknowledgements......Page 245
9.11 References......Page 246
10.1 Introduction......Page 252
10.2 Temperature Regulates Development in Nematodes......Page 253
10.3 How Does Caenorhabditis elegans Sense Temperature?......Page 254
10.4 Temperature Sensing in Parasitic Nematodes......Page 256
10.5 Heat Shock Factor – the Master Regulator of the Heat Shock Response......Page 257
10.6 Integration of the Stress Response and Developmental Pathways......Page 259
10.7 Heat Shock Protein Families......Page 261
10.7.1 Hsp90......Page 262
10.7.2 The small heat shock protein family......Page 264
10.7.3 Hsp70......Page 265
10.8 Conclusions and Future Directions......Page 266
10.10 References......Page 268
11.1 Introduction......Page 275
11.2.1 Measuring internal osmotic concentration, water flux and volume changes......Page 276
11.2.2 The importance of balanced salt solutions......Page 279
11.2.4 Hyperosmotic or hyposmotic regulation?......Page 280
11.2.5 Ionic regulation......Page 282
11.3 Avoidance of Osmotic Stress......Page 285
11.4 Survival of Extreme Osmotic/Ionic Stress......Page 286
11.5.1 Excretory structures and osmoregulation......Page 287
11.5.2 Cuticular permeability......Page 288
11.5.3 The operation and control of osmoregulatory mechanisms......Page 289
11.5.4 Aquaporins......Page 292
11.6 Conclusions and Future Directions......Page 293
11.8 References......Page 294
12.1 Introduction......Page 301
12.2.1 Temperature and protein stability......Page 302
12.2.2 Enzymes in hot- and cold-adapted animals......Page 303
12.2.3 Proteins and hydrostatic pressure......Page 304
12.2.4 Stress proteins......Page 305
12.3.1 Xenobiotic metabolism......Page 306
12.3.4 Heavy metals......Page 309
12.3.5 Antioxidant systems......Page 310
12.4.1 Aerobic metabolism......Page 311
12.4.2 Anaerobic metabolism......Page 313
12.4.3 Animal-parasitic nematodes......Page 314
12.4.5 The thiobios......Page 317
12.6 Membranes and Temperature......Page 318
12.6.1 Intrinsic adaptations to temperature......Page 319
12.6.2 Extrinsic adaptations to temperature......Page 320
12.8 Membranes and Desiccation......Page 321
12.8.1 Osmotic stress......Page 322
12.10 References......Page 323
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