Dormancy and Resistance in Harsh Environments (eBook)

Contents 8
Contributors 10
Chapter 1: Introduction 14
1.1 Dormancy 14
References 17
Chapter 2: Akinetes: Dormant Cells of Cyanobacteria 18
2.1 Introduction 14
2.2 Structure, Composition, and Metabolism of Akinetes 20
2.3 Factors that Influence Akinete Differentiation 22
2.4 Factors Influencing Akinete Germination 25
2.5 The Germination Process 27
2.6 Ecological Functions of Akinetes 28
2.7 Genes Involved in Akinete Differentiation 29
2.8 Similarity of Akinetes to Dormant Forms of Other Prokaryotes 32
2.9 Conclusions and Future Prospects 34
References 35
Chapter 3: Saccharomyces cerevisiae Spore Germination 41
3.1 Saccharomyces cerevisiae as a Model Organism for Dormancy 42
3.2 Yeast Sporulation 42
3.3 The Dormant Spore 43
3.4 Germination 44
3.4.1 Nutritional Requirements for Germination 44
3.4.2 Germination: The Process 45
3.4.3 Macromolecular Synthesis and Degradation 46
3.4.4 Trehalose Breakdown 46
3.4.5 Global Changes in Gene Expression During Germination 47
3.4.5.1 Two Stages of Germination Prior to the First Mitotic Cell Cycle 47
3.4.5.2 Germination and the General Response of Yeast Cells to Glucose 49
3.4.6 Conjugation Between Germinating Spores of Opposite Mating Type 49
3.4.7 Specific Proteins Required for Germination 50
3.4.8 Future Challenges 51
References 51
Chapter 4: Dormancy in Plant Seeds 54
4.1 Introduction 55
4.1.1 Embryo-Endosperm Interaction as a Mechanistic Model for Germination 56
4.2 Seed Dormancy Research: An Update 57
4.2.1 Global Analysis 57
4.2.1.1 Similarities and Differences between Physiological States 58
4.2.1.2 Genes Associated with Different States 59
4.2.1.3 The Hormone Balance and Regulation of Dormancy 60
4.2.1.4 Exposure to Dormancy Releasing Environmental Factors 61
4.2.1.5 Different Seed Tissues and Sensitivities 62
4.2.2 Specific Analyses: Key Genes and Processes Related to the Hormonal Regulation of Dormancy, After-Ripening and Germination 63
4.2.2.1 ABA: A Positive Regulator of Dormancy Induction and Maintenance, and a Negative Regulator of Germination 63
4.2.2.2 Gibberellins Release Coat Dormancy, Promote Germination and Counteract ABA Effects 64
4.2.2.3 Identification of Dormancy-Specific Genes and Other Key Genes that Control Germination Timing 66
4.2.2.4 Control of Germination by the Seed Coat: Testa Mutant Studies 67
4.2.2.5 Control of Germination by the Endosperm: Endosperm Dormancy and Endosperm Weakening 68
4.3 Dormancy and Harsh Environments 70
4.3.1 Seed Dormancy and Tolerance in the Dry State 70
4.3.2 Stress Tolerance of Dormant Seeds in the Hydrated State 71
4.4 Future Prospects 73
References 73
Chapter 5: Bud Dormancy in Perennial Plants: A Mechanism for Survival 79
5.1 Introduction 79
5.1.1 Bud Phenology in Model Perennials 81
5.1.1.1 Woody Perennials 81
5.1.1.2 Herbaceous Perennials 83
5.2 Environmental Regulation 84
5.2.1 Light 84
5.2.2 Temperature 88
5.2.2.1 Cold-Hardening/Cold-Acclimation 88
5.2.2.2 Vernalization 89
5.3 Genetic/Physiological Model(s) for Regulation of Dormancy Transitions 90
5.3.1 Hormones 92
5.3.2 Sugar 93
5.4 Conclusions 94
References 95
Chapter 6: LEA Proteins: Versatility of Form and Function 101
6.1 Introduction 101
6.1.1 Anhydrobiosis and Desiccation Tolerance 101
6.1.2 Mechanisms of Desiccation Tolerance 102
6.1.3 Unstructured, Highly Hydrophilic Proteins 103
6.2 LEA Protein Function 105
6.2.1 Protein Protection 105
6.2.2 Membrane Protection 109
6.2.3 The Glassy State 111
6.3 The Versatility of LEA Proteins 112
References 114
Chapter 7: A Role for Molecular Studies in Unveiling the Pathways for Formation of Rotifer Resting Eggs and Their Survival During Dormancy 119
7.1 Introduction 120
7.2 Switching from Asexual to Sexual Reproduction and the Onset of Meiosis 121
7.2.1 The Rotifer Life Cycle 121
7.2.2 Formation of Resting Eggs 125
7.2.3 Factors Affecting the Formation of Resting Eggs 125
7.2.3.1 External Factors 126
7.2.3.2 Intrinsic Factors 126
7.2.3.3 Hormones 127
7.2.3.4 Future Directions 127
7.3 The Resting Egg and Its Morphology 128
7.4 Diapause and Hatching of Resting Eggs 130
7.5 Molecular Aspects of Rotifer Functional Biology and Dormancy 131
7.6 Conclusions and Future Directions 134
References 136
Chapter 8: Anhydrobiotic Abilities of Tardigrades 143
8.1 Discovery of the Tardigrades 143
8.2 Cryptobiosis 145
8.3 Longevity and Long-Term Anhydrobiotic Ability 146
8.3.1 Longevity in Tardigrades 146
8.3.2 Long-Term Anhydrobiotic Ability of Tardigrades 146
8.4 DNA Damage and Repair Mechanisms 147
8.5 Protection and Repair with Proteins 148
8.5.1 Heat Shock Proteins 148
8.5.2 LEA Proteins 149
8.6 Sugars and Vitrification 149
8.6.1 Hypothesis of Cell Stabilization 149
8.6.2 The Role of Sugars in Tardigrades 150
8.6.3 Vitrification in Tardigrades 151
References 152
Chapter 9: Cryoprotective Dehydration: Clues from an Insect 157
9.1 Introduction 157
9.2 Laboratory Induced Cold Tolerance in M. arctica 159
9.3 Trehalose as a Cryo/Anhydro Protectant 163
9.3.1 Duplication of TPS Genes in M. arctica 165
9.4 Reactive Oxygen Species and Antioxidant Enzymes 167
9.5 Phospholipid Fatty Acid Composition 168
9.6 Summary 169
References 170
Chapter 10: A Molecular Overview of Diapause in Embryos of the Crustacean, Artemia franciscana 174
10.1 Introduction 174
10.1.1 Diapause 174
10.1.2 Artemia franciscana Life History 175
10.2 Gene Expression During Diapause 177
10.2.1 Identification by Subtractive Hybridization of Differentially Regulated Genes in Diapause-Destined Artemia Embryos 177
10.2.2 Other Examples of Diapause-Dependent Gene Regulation in Arthropods 182
10.3 p8, a Transcription Co-factor Up-regulated Early in Artemia Diapause 183
10.3.1 Characterization of p8 183
10.3.2 Developmental Regulation of p8 in Artemia Embryos 184
10.3.3 Diapause-Related Transcription Factors in Organisms Other than Artemia 185
10.4 sHSPs and Diapause Maintenance in A. franciscana 187
10.4.1 Artemia sHSPs 187
10.4.2 sHSP Synthesis and Localization in Diapause-Destined Artemia Embryos 188
10.4.3 Diapause-Related sHSPs in Organisms Other than Artemia 191
10.5 Conclusions 192
References 192
Chapter 11: An Exploratory Review on the Molecular Mechanisms of Diapause Termination in the Waterflea, Daphnia 197
11.1 Introduction 197
11.2 Ecological and Evolutionary Implications of Diapause 198
11.3 Characteristics of the Diapause State 200
11.3.1 Metabolic Rate and Energy Reserves 200
11.3.2 Proteins and RNA 200
11.4 Diapause Termination and Hatching 201
11.4.1 Light and Photoreceptors 202
11.4.2 Oxidation 203
11.4.3 Downstream Cellular Activation 204
11.4.4 pH 206
11.5 Research Perspectives 206
References 207
Chapter 12: Metabolic Dormancy and Responses to Environmental Desiccation in Fish Embryos 211
12.1 Introduction 211
12.2 Delayed Hatching 212
12.2.1 Advanced Hatching: The Case of F. heteroclitus Embryos 214
12.3 Embryonic Diapause 215
12.3.1 Evolutionary History of Diapause in Annual Killifish 216
12.3.2 The Life History of Annual Killifish 217
12.3.3 Diapause I 217
12.3.4 Diapause II 218
12.3.5 Diapause III 218
12.3.6 Environmental Control of Diapause II 219
12.3.7 Alternate Developmental Pathways Associated with Escape Embryos 219
12.4 Diapause and Tolerance to Environmental Stress 221
12.4.1 Temperature Tolerance 222
12.4.2 Salinity Tolerance 223
12.4.3 Anoxia Tolerance 224
12.4.4 Dehydration Tolerance 224
12.4.4.1 Role of Aquaporins During Dehydration Resistance 227
12.5 Future Prospects 228
References 229
Chapter 13: Mammalian Hibernation: Physiology, Cell Signaling, and Gene Controls on Metabolic Rate Depression 235
13.1 Metabolic Depression in Hibernation 235
13.1.1 Endocrine Signaling 239
13.2 Metabolic Regulation by Reversible Phosphorylation 240
13.3 Metabolic Signaling in Hypometabolic States 241
13.3.1 The AMP-Activated Protein Kinase (AMPK) System 243
13.3.2 AMPK in Hypometabolic States 244
13.3.3 AMPK in Mammalian Hibernation 245
13.4 Transcriptional Silencing and Epigenetic Mechanisms 246
13.5 Regulation of mRNA Transcripts: The New Frontier of microRNA 249
13.6 Transcription Factors and Hibernation-Responsive Gene Expression 250
13.7 Concluding Remarks 254
References 254
Chapter 14: Lessons from Natural Cold-Induced Dormancy to Organ Preservation in Medicine and Biotechnology: From the ``Backwoods to the Bedside" 261
14.1 Introduction 261
14.2 Organ Injury from Hypoxia 263
14.3 Effects of Cooling and Hypothermic Preservation on Mammalian Cells 264
14.4 History of Organ Preservation for Transplantation 267
14.5 Cold Survival Strategies: The Links Between Medicine and Nature 268
14.6 Application of Cooling and Additional Hypometabolism by Manipulation of Preservation Solutions 270
14.7 Hypothermic Machine Perfusion Preservation 273
14.8 New Areas of Research in Organ Preservation 277
14.8.1 Towards a Single Preservation Solution 277
14.8.2 Novel Modulation of the Hypometabolic State 277
14.8.3 A Role for Other Bioactive Gases 278
14.8.4 Oxygen Supply at Hypothermia 278
14.9 Summary 281
References 281
Index 287