(Endo)symbiotic Methanogenic Archaea (eBook)

Preface 6
References 8
Contents 10
Contributors 12
Free-Living Protozoa with Endosymbiotic Methanogens 16
1 Discovery 17
2 Distribution 18
3 Morphology and Life Cycles 20
4 Significance of the Association 20
5 Intracellular H2-Tension and Methanogens 22
6 Symbiotic Consortia as Natural Chemostats 23
7 The Role of Symbiotic Methanogenesis in Natural Habitats 23
References 24
Anaerobic Ciliates and Their Methanogenic Endosymbionts 27
1 Introduction 28
2 Methanogenic Endosymbionts Are Transmitted Vertically 29
3 Studies of the SSU rRNA Genes of Host and Symbiont 29
4 Endosymbiont Replacements 32
References 35
Symbiotic Methanogens and Rumen Ciliates 38
1 The Rumen and Ciliated Protozoa 39
2 Methanogens Associated with Rumen Ciliates 40
3 Detection of Methanogens Associated with Ciliates 40
4 The Effect of Ciliated Protozoa on the Composition of Methanogenic Archaea in the Rumen 44
References 46
The Methanogenic and Eubacterial Endosymbionts of Trimyema 48
1 Monoxenic and Axenic Cultures of Trimyema 49
2 Metabolic Features of Trimyema 52
3 Methanogenic Symbionts 55
4 Bacterial Symbionts 59
5 Perspectives 63
References 63
Termite Gut Flagellates and Their Methanogenic and Eubacterial Symbionts 67
1 Introduction 68
2 Methanogenic Endosymbionts of Termite Gut Flagellates 71
2.1 Phylogeny of Endosymbiotic Methanogens 71
2.2 Predicted Functions of Endosymbiotic Methanogens 73
3 Eubacterial Symbionts of Termite Gut Flagellates 77
3.1 Phylogeny of Ectosymbiotic Eubacteria 77
3.2 Phylogeny of Endosymbiotic Eubacteria 79
3.3 Predicted Functions of Eubacterial Symbionts 82
4 Genomics of Endosymbionts 83
5 Concluding Remarks and Future Perspectives 84
References 86
Methanogens in the Digestive Tract of Termites 92
1 Introduction 93
2 Methane as a Product of Symbiotic Digestion 94
3 Diversity of Methanogens in Termite Guts 96
4 Differences in Methanogenic Activities and Populations 99
5 Coexistence with Homoacetogens 100
6 Association with Gut Flagellates 102
7 Intercompartmental Transfer of Hydrogen 103
8 Relationship to Oxygen 105
9 Termites as a Source of Atmospheric Methane 105
10 Conclusions 106
References 107
Methanogenic Archaea in Humans and Other Vertebrates 112
1 Objective and Scope 113
2 Methanogens in Humans 113
3 Methanogens in Nonhuman Vertebrates 114
4 Diversity of Methanogens in Vertebrates 118
5 Diversity at the Subspecies Level 120
6 Methanogens in Vertebrates and Atmospheric Methane 120
7 Conclusions 121
References 122
Methanogens in the Gastro-Intestinal Tract of Animals 125
1 Introduction 126
2 Vertebrates 126
3 Arthropods 134
4 Conclusions 148
References 148
Syntrophy in Methanogenic Degradation 153
1 Introduction 154
2 Syntrophic Culture Systems, Microbiology, Biochemistry, and Molecular Biology 158
2.1 Ethanol 158
2.2 Butyrate 160
2.3 Propionate 162
2.4 Acetate 166
2.5 Branched Fatty Acids 167
2.6 Benzoate 167
2.7 Sugars 168
2.8 Amino Acids 169
2.9 Carrier Systems 171
2.10 Alternative Substrates for Pure Cultures and Technical Systems to Replace Methanogens 172
2.11 Anaerobic Methane Oxidation 174
3 Spatial Organization of Syntrophic Communities 174
4 Concluding Remarks 175
References 176
Hydrogenosomes 184
1 Introduction 185
2 The Hydrogenosomes of the Trichomonadina 187
3 The Hydrogenosomes of T. pyriformis 190
4 The Hydrogenosomes of P. lanterna 191
5 The Hydrogenosomes/Mitochondrion-like Organelles (MLOs) of Blastocystis sp. 193
6 The Hydrogenosomes of Chytridiomycete Fungi 195
6.1 Mitochondria versus Hydrogenosomes 196
6.2 Chytrids Perform a ``Mixed Acid Fermentation´´ 196
6.3 The Hydrogenosomal Metabolism 198
6.4 The Role of the Hydrogenosomes in the Energy Metabolism of Piromyces sp. E2 199
6.5 The Evolution of Hydrogenosomes from Fungal Mitochondria 200
7 The Hydrogenosomes of Anaerobic Ciliates 201
7.1 N. ovalis 203
7.2 In Silico Reconstruction of the Basal Hydrogenosomal Metabolism of N. ovalis 204
7.3 The Hydrogenosomes of Other Ciliates 205
7.4 Can the Methanogenic Symbionts Tell Us More about the Origin and Function of Ciliate Hydrogenosomes? 206
7.5 Evolutionary Aspects 207
8 Conclusions 209
References 209
Evolution of Prokaryote-Animal Symbiosis from a Genomics Perspective 216
1 Introduction 217
2 Survival, Replication and Transmission, the Three Biological Processes Involved In the Establishment of a Permanent Symbiotic Association 223
3 Early Stages In the Symbiotic Relationship 225
3.1 Facultative Symbionts 225
3.2 Insertion Sequences, Shaping the First Steps Towards an Obligate Endosymbiosis 227
4 Long-Established P-Endosymbioses 230
5 Final Stages in Endosymbiotic Relationships 233
6 Replacement or Complementation, and the Establishment of Microbial Consortia 234
7 Concluding Remarks 236
References 237
Index 243