Advances in Parasitology (eBook)

Cover 1
Advances in Parasitology 4
Contributors to Volume 60 6
Preface 8
Contents 10
Sulfur-Containing Amino Acid Metabolism in Parasitic Protozoa 14
Introduction 18
Biological Importance of Sulfur-containing Amino Acids and their Metabolic Pathways 19
General Features and Functions of Sulfur 19
Functions of Sulfur-Containing Amino Acids 19
General Functions of Sulfur-Containing Amino Acids 19
Functions of AdoMet 21
Significance of Sulfur-Containing Amino Acids in Parasitic Protozoa 23
Significance of Methionine in Parasitic Protozoa 23
Requirement of Extracellular Cysteine for Anaerobic or Microaerophilic Protozoa 24
Significance of Cysteine as an Antioxidant in Entamoeba histolytica, Giardia duodenalis and Trichomonas vaginalis 24
Physiological Importance of Cysteine in Trypanosoma and Leishmania 25
Metabolism of Sulfur-containing Amino Acids 26
An Overview of Metabolism of Sulfur-Containing Amino Acids 26
Methionine Metabolism 27
A General Scheme of Methionine Activation 27
A General Scheme of Two Pathways for Methionine Recycling 28
Ubiquity and Significance of Methionine Activation in Parasitic Protozoa 32
Distribution and Significance of the Methionine Recycling Pathways in Protozoa 39
S-Adenosylmethionine Decarboxylase (AdoMetDC) from Protozoan Parasites 42
Transsulfuration Reactions 44
Terminology and General Description of Forward and Reverse Transsulfuration Pathways 44
Transsulfuration Pathway in Animals 45
Transsulfuration Pathway in Bacteria, Fungi and Plants 46
Transsulfuration Pathways in Parasitic Protozoa 47
Sulfur Assimilatory De Novo Cysteine Biosynthetic Pathway 49
A General Scheme of the Cysteine Biosynthetic Pathway 49
Presence of the Cysteine Biosynthetic Pathway in a Limited Range of Parasitic Protozoa 50
Possible Functions of the Cysteine Biosynthetic Pathway in Entamoeba and Trypanosoma 52
Contradiction Between the Presence of Cysteine Biosynthesis and the Apparent Requirement of Cysteine in Entamoeba histolytica 52
Roles of the Cysteine Biosynthetic Pathway in Antioxidative Defense Mechanisms and ISC Biosynthesis in Entamoeba histolytica 53
Roles of the Cysteine Biosynthetic Pathway in Trypanosoma cruzi 55
Other Possible Roles of the Cysteine Biosynthetic Pathway in Parasitic Protozoa and Possible Drug Development 56
Degradative Pathways of Sulfur-containing Amino Acids 58
Degradation of Sulfur-Containing Amino Acids in Mammals 58
Peculiarities and Distribution of MGL among Parasitic Protozoa 59
Functions of MGL in the Anaerobic Protozoan Parasites Entamoeba histolytica and Trichomonas vaginalis 61
MGL as a Target for the Development of Novel Drugs Against Entamoeba histolytica and Trichomonas vaginalis 63
Serine Metabolic Pathways 64
Serine Metabolic Pathways in Eukaryotes 64
A General Scheme of Phosphorylated and Non-phosphorylated Serine Metabolic Pathways in Mammals 64
Regulation of the Phosphorylated Serine Metabolic Pathway 64
Serine Dehydratase for Serine– Pyruvate Conversion and Gluconeogenesis in Mammals 67
Serine-Glycine Conversion by Serine Hydroxymethyltransferase 67
Human Genetic Disorders and Physiological Importance of the Serine Metabolic Pathway 68
A Spectrum of Serine Metabolic Pathways in Parasitic Protozoa 69
A Survey of Enzymes of Phosphorylated and Non-phosphorylated Serine Metabolic Pathways in Parasitic Protozoa 69
Distribution of Serine-Glycine and Serine-Pyruvate Conversion Pathways in Parasitic Protozoa 71
Unique Presence of Both Serine Metabolic Pathways in Entamoeba histolytica and Trichomonas vaginalis 73
The Phosphorylated Serine Pathway in Entamoeba histolytica 74
The Non-Phosphorylated Serine Pathway in Entamoeba mbihistolytica 75
Origin of Serine Metabolic Pathways in Entamoeba .16em histolytica and Trichomonas vaginalis 76
Biological Significance of Serine Metabolic Pathways in Parasitic Protozoa 77
Developmental Stage Regulation of Metabolic Pathways of Sulfur-containing Amino Acids 79
Developmental Stage Regulation of Reverse Transsulfuration and De Novo Cysteine Biosynthetic Pathways in Trypanosoma cruzi 79
Developmental Stage Regulation of Sulfur-Containing Amino Acid Metabolism in Plasmodium and Cryptosporidium 80
Remaining Questions and Future Perspectives 82
Acknowledgments 83
References 84
The Use and Implications of Ribosomal DNA Sequencing for the Discrimination of Digenean Species 114
Introduction 116
The Digenea 116
Species Distinction: Traditional and Modern Approaches 117
Advantages and Disadvantages of Using Molecular Techniques for Systematic Studies 118
Genes and Spacers 119
Ribosomal DNA 120
Internal Transcribed Spacer rDNA (ITS1, 5.8S rRNA Gene and ITS2) Region 122
Internal transcribed spacer 1 (ITS1) of rDNA 123
Internal transcribed spacer 2 (ITS2) of rDNA 123
Studies Using Its rDNA to Distinguish Digenean Species 124
Apocreadiidae 125
Bivesiculidae 125
Cladorchiidae 125
Didymozoidae 125
DiplostomidaeDagger 126
Echinostomatidae 127
Fasciolidae 128
Haematoloechidae 129
Lepocreadiidae 130
Leucochloridiidae 130
Mesometridae 131
Monorchiidae 131
Opecoelidae 132
Paragonimidae 133
Plagiorchiidae 138
Sanguinicolidae 138
Schistosomatidae 138
Strigeidae 144
Telorchiidae 145
The Interpretation of Its rDNA Sequences 145
Identical Sequences, Different Species 146
Interspecific Variation 148
Intraspecific Variation 149
Error 149
Failure to Recognise Multiple Species 151
Geographical Variation 153
‘‘Real’’ Intraspecific Variation 156
The Recognition of Species 157
Implications of Its Sequencing for Digenean Taxonomy 159
Implications for Species Richness 160
Implications for Morphological Taxonomy 161
When to Name a New Species? 162
Conclusions 166
Is ITS Sequencing Effective? 166
Remaining Problems 167
An Effective Study 168
References 169
Advances and Trends in the Molecular Systematics of the Parasitic Platyhelminthes 178
Introduction 179
DNA Taxonomy 181
The Platyhelminthes as Lophotrochozoan Bilaterians 182
Interrelationships and Position of the Neodermata 183
Abbreviations 184
Molecular Systematics of the Cestoda 185
Interrelationships of the Major Lineages of Cestodes 185
Inter- and Intraspecific Variation in the Cestodes 189
Molecular Systematics of the Digenea 193
Non-Sequence-Based Works 194
Interrelationships of the Major Lineages of Digeneans 195
Interrelationships of Genera and Families 198
Inter- and Intraspecific Variation in the Digeneans 200
Systematics of Schistosoma and Related Blood Flukes 200
Systematics of the Liver Flukes Fasciola and Paragonimus 202
Systematics of Animal Flukes 203
Molecular Systematics of the Monogenea 207
Non-Monophyly of the Monogenea 208
Interrelationships of the Monopisthocotylea and Polyopisthocotylea 209
Systematics of Select Groups 211
Udonella as a Monopisthocotylean Monogenean 212
Systematics of the Dactylogyridae 213
Systematics of the Polystomatidae 213
Systematics and Diagnostics in Gyrodactylus 214
Beyond Systematics: Molecular Diagnostics 217
Ecological Diagnostics and Life Cycle Studies 219
Cestoda 219
Digenea 220
Clinical Diagnostics 221
Future Directions 222
Taxonomic Considerations 222
Analytical Considerations 224
Molecular Targets 225
Genomics 225
Mitochondrial Genomes 225
Nuclear Genomes and Transcriptomes 226
Acknowledgments 228
References 228
Wolbachia Bacterial Endosymbionts of Filarial Nematodes 258
The Cellular Environment of Wolbachia in Nematodes 259
Habitat 259
Growth and Population Dynamics 261
Taxonomy and Diversity of the Genus Wolbachia 262
Wolbachia in Arthropods 265
Wolbachia in Nematodes 265
Distribution and Phylogeny of Wolbachia in the Onchocercinae and Dirofilarinae 269
Evidence for Dependence 271
Indirect Evidence 271
Direct Evidence 273
Antibiotic Therapy as a New Treatment for Human Filariasis 276
Genomic Insights into the Nature of the Symbiosis 279
Wolbachia-Mediated Activation of Inflammation 281
Lymphatic Filariasis 281
Onchocerciasis 283
Dirofilariasis 284
Wolbachia Serology 285
Future Advances/Concluding Remarks 286
References 287
The Biology of Avian Eimeria with an Emphasis on their Control by Vaccination 298
Introduction 300
Eimeria spp. and the Need for their Control 300
Life Cycles of Eimeria spp., Including the Relevance of Different Endogenous Stages to the Induction of Protective Immunity 302
Immunity to Eimeria spp. 305
The Immunological Relationship between the Host and Eimeria spp. 305
Protective Immune Responses 307
Vaccine Strategies 310
Live Vaccines 310
Wild-type Strains of Eimeria spp. 310
Live-Attenuated Vaccines 312
Use and Efficacy of Live Vaccines 316
Antigenic Diversity 320
Maternal Immunisation—Transmission Blocking Immunity 323
Prospects for the Development of Novel Vaccines 324
Recent Advances that have Relevance to Vaccine Development 324
Testing of Recombinant-Expressed Antigens as Vaccines 327
DNA Vaccination 328
Conclusions 329
References 331
Index 344
Contributors to Volume 60 6