Endosymbionts in Paramecium (eBook)

Preface 6
Contents 8
Origins of Algal Symbionts of Paramecium bursaria 10
1 Introduction 11
2 Classical Approaches to the Identification of Symbionts 12
3 Molecular Phylogeny of the Symbionts 16
4 Symbiont rDNA Group I Introns 28
5 Host-Symbiont Specificity 30
6 Concluding Remarks and Evolutionary Considerations 32
References 35
Infection of Paramecium bursaria by Symbiotic Chlorella Species 40
1 Introduction 41
2 Differentiation of DVs of P. bursaria 43
2.1 Morphological Classification of DVs and Timing of Appearance of Each DV 43
2.2 Timing of Acidosomal Fusion to DVs 46
2.3 Timing of Lysosomal Fusion to DVs 47
3 Fates of Chlorella Cells in Infection 47
3.1 Acquisition of Temporal Resistance to Lysosomal Enzymes in the Host DVs 49
3.2 Escape from the Host DVs by Budding of the Membrane 51
3.3 Differentiation of PV Membrane 51
3.4 Translocation and Attachment Beneath the Host Cell Surface 52
3.5 Cell Division of Algae After Establishment of Endosymbiosis 53
4 Different Behaviors in Infection Between Infection-Capable and Infection-Incapable Chlorella Species 53
4.1 Infectivity of Various Symbiotic and Free-Living Chlorella Species 53
4.2 Lectin Binding Ability of Symbiotic and Free-Living Chlorella Species 54
5 Characteristics of PV Membrane 55
5.1 Protection from Lysosomal Fusion 57
5.2 Synchronous Swelling of PVs 57
6 Protection of Symbiotic Algae from Chlorella Virus by Endosymbiosis 58
7 Concluding Remarks and Further Perspectives 60
References 61
Metabolic Control Between the Symbiotic Chlorella and the Host Paramecium 66
1 Introduction 67
2 Features of Symbiotic Chlorella Species 68
2.1 European and American Symbiotic Chlorella 68
2.2 Japanese Symbiotic Chlorella 69
2.3 Nitrogen Utilization of Symbiotic Chlorella 70
3 Amino Acid Transport of Symbiotic Chlorella and Its Regulation Factors 73
3.1 Amino Acid Uptake by Symbiotic Chlorella 73
3.2 Amino Acid Transport Systems 74
3.3 Factors Affecting Amino Acid Transport 76
4 Photosynthesis of Symbiotic Chlorella and Its Regulatory Factors 81
4.1 Features of Photosynthesis in Symbiotic Chlorella 82
4.2 Effects of Host Extracts on Carbon Dioxide Fixation by Symbiotic Chlorella 82
4.3 Factors Affecting Photosynthesis of Symbiotic Chlorella 84
5 Conclusions 86
References 88
Regulation of Circadian Rhythms of Paramecium bursaria by Symbiotic Chlorella Species 92
1 Introduction 93
2 Features of Circadian Rhythms 94
2.1 Mating Reactivity Rhythm 95
2.2 Photoaccumulation Rhythm 96
2.3 Phase Shift by Light Pulses 99
3 Effects of Symbiotic Chlorella sp. on Circadian Rhythms 101
3.1 Period Length 101
3.2 Phase Shift 103
3.3 Expression of Mating Reactivity Rhythms 105
4 Effects of Photosynthetic Products 106
4.1 Rescue of Mutant 106
4.2 Acquisition of Various Stress Resistances 108
5 Effects of Symbiotic Chlorella sp. on the Life Cycle 110
5.1 Length of Immaturity 111
5.2 Circadian Clock and Developmental Clock 112
6 Concluding Remarks and Future Perspectives 114
References 116
Photobiological Aspects of the Mutualistic Association Between Paramecium bursaria and Chlorella 120
1 Introduction 120
1.1 The “Classical” View of Mutual Benefits 121
1.2 Photoprotection in Chlorella-Ciliate Symbiosis 123
2 UV-Induced Accumulation Behavior of Symbiotic P. bursaria 125
3 Photoprotection of P. bursaria by Chlorella Self-Shading 127
4 Role of Endosymbiotic Chlorella in the (Photo-)oxidative Stress Balance of P. bursaria 128
5 Antioxidative Capacity of the P. bursaria–Chlorella Symbiosis 132
6 Conclusions and Perspectives 134
End Note 135
References 135
Diversity of Endosymbiotic Bacteria in Paramecium 140
1 Introduction 141
2 Symbiont Diversity in Paramecium and its Research 142
2.1 Symbiont Diversity 142
2.2 Research Fields 143
3 Compartments of the Paramecium Cell Colonized by Bacterial Symbionts 145
3.1 Cytoplasm 146
3.2 Micronuclei 148
3.3 Macronuclei 149
4 Bacteria in Paramecium Given Binomial Names (Except Holospora 151
4.1 Caedibacter 151
4.2 Pseudocaedibacter 153
4.3 Lyticum 154
4.4 Pseudolyticum 154
4.5 Tectibacter 155
4.6 Nonospora 156
5 Bacteria in Paramecium Not Given Binomial Names 156
5.1 Bacteria in Paramecium bursaria 156
5.2 Bacteria in Paramecium calkinsi 157
5.3 Bacteria in Paramecium caudatum 158
5.4 Bacteria in Paramecium duboscqui 158
5.5 Bacteria in Paramecium multimicronucleatum 159
5.6 Bacteria in Paramecium nephridiatum 159
5.7 Bacteria in Paramecium putrinum 159
5.8 Bacteria in Paramecium pentaurelia 160
5.9 Bacteria in Paramecium sexaurelia 161
6 Phylogeny of Bacteria in Paramecium 162
7 Conclusions 164
References 164
Diversity of Holospora Bacteria in Paramecium and Their Characterization 170
1 Introduction 171
2 History of Holospora’s Discovery and Steps in Its Investigation 173
3 Holospora Species in Different Species of the Genus Paramecium 179
3.1 Holospora spp. Known from Paramecia 179
3.2 Host and Nuclear Specificity for Different Holosporas 183
3.3 Morphological Peculiarities 184
3.4 Frequency of the Infection in the Natural Population 185
3.5 Stability of the Infection in Laboratory Cultures 186
4 Life Cycle of Holospora Bacteria 187
4.1 General Description 187
4.2 Way up to the Target Nucleus 190
4.3 Reproduction in the Nucleus 190
4.4 Release of the Infectious Forms from the Host Cell 190
4.5 Holospora as a Vector for Other Bacteria 191
5 Two Holospora Groups and Some Biological Features of Them 191
5.1 Groups Distinguishable by 16S Ribosomal DNA Probes 192
5.2 Behavior of Different Holospora Species During Nuclear Division of the Host 194
5.3 Behavior of Different Holospora Species During the Sexual Process of the Host Cell 194
5.4 Phylogenetic Positions and Taxonomy of the Endocytobionts 195
6 Host Cell Resistance Against Holospora Infection 196
6.1 General Remarks 196
6.2 Experimental Data 197
7 Simultaneous Infection of the Host with Different Holospora and Other Bacteria 199
7.1 Holospora and Holospora-Like Endosymbiotic Bacteria in Other Ciliates 200
7.2 Ecological and Evolutionary Significance of Holospora Infection 201
8 Concluding Remarks and Further Perspectives 202
References 203
Infection and Maintenance of Holospora Species in Paramecium caudatum 210
1 Introduction 211
2 Reproductive Form and Infectious Form of Holospora 212
2.1 Triggers for Differentiation 212
2.2 Isolation of Holospora from Host Cells 213
2.3 Cryopreservation of Isolated Infectious Forms 214
2.4 Form-Specific Antigens 215
3 Infection Process of Holospora 218
3.1 Invasion-Tip-Specific Proteins 218
3.2 Actin-Based Motility of Holospora 220
3.3 Recognition of the Target Nuclear Envelope 222
3.4 Penetration of the Target Nuclear Envelope and Invasion of the Nucleus 224
4 Infectivity of Holospora Against the Target Nucleus 224
4.1 Sensitivity of Bacterial Infectivity to Chemical and Physical Factors 225
4.2 Holospora Infects Phylogenetically Closed Paramecium Species 225
4.3 Timing of Appearance of Nuclear Infectability During Nuclear Differentiation 226
5 Maintenance of Infected Holospora 226
5.1 Species Specificity and Strain Specificity of Maintenance 227
5.2 Fate of Holospora Injected into a Nontarget Nucleus 228
6 Effects of Infection of Holospora on the Host 228
6.1 Holospora -Induced Alteration of the Host’s Gene Expression 229
6.2 Advantages and Disadvantages for the Host 229
7 Concluding Remarks and Further Perspectives 230
References 230
The Killer Effect of Paramecium and Its Causative Agents 235
1 Introduction 236
2 Ecology of the Killer Trait 236
2.1 Ecological Impact of the Killer Trait 236
2.2 Diversity of Caedibacter Hosts 241
2.3 Taxonomy and Phylogeny of Caedibacter Species 241
3 Cellular and Genetical Background of the Killer Trait 243
3.1 Cellular Effects of the Killer Trait 243
3.2 Genetic Determinants of R-Bodies and Toxins 245
4 Structure and Function of R-Bodies 247
4.1 Composition and Structure of R-Bodies 247
4.2 Spatial Association with Bacteriophages 249
5 Concluding Remarks and Further Perspectives 250
References 251
Index 255