Toxicology of Reptiles

Front cover......Page 1
Contributors......Page 6
Foreword......Page 8
References......Page 10
Acknowledgments......Page 12
Contents......Page 14
II. Reptilian Toxicology......Page 16
III. Summary......Page 22
Global Threats Affecting the Status of Reptile Populations......Page 24
I. Introduction......Page 25
A. Life Span and Sexual Maturity......Page 27
C. Geographic Distribution......Page 29
A. Conversion to Agriculture......Page 30
C. Habitat Fragmentation......Page 31
E. Coastal Development......Page 32
A. Disease......Page 33
B. Drought......Page 34
A. Consumptive Uses......Page 35
C. Pet Trade......Page 37
A. Exotic and Invasive Species Introductions......Page 38
B. Indirect Impacts......Page 40
VII. Summary......Page 41
Literature Cited......Page 42
I. Introduction......Page 50
III. A Call for Integration and Experimentalism......Page 53
A. Mechanisms of Contaminant Uptake in Juveniles and Adults......Page 60
B. Mechanisms of Contaminant Uptake in Embryos......Page 62
C. Factors Influencing Accumulation and Distribution among Tissues......Page 64
D. Contaminant Transport in Ecologic Systems......Page 68
V. Summary......Page 69
Acknowledgments......Page 70
Literature Cited......Page 71
Tools for Assessing Contaminant Exposure and Effects in Reptiles......Page 78
A. Overview......Page 79
B. Tools to Assess Contaminant Exposure and Effects (Biomarkers)......Page 80
C. Assessing Contaminant Exposure and Effects in Reptiles - Why?......Page 83
A. Molecular Biomarkers......Page 85
1. mRNA Isolation......Page 87
2. Northern Blotting......Page 88
3. Quantitative Real-Time Polymerase Chain Reaction......Page 89
4. Open-Ended Methods......Page 92
B. Biochemical Biomarkers......Page 94
1. Phase I Biotransformation; Cytochrome P450 Enzyme System......Page 95
2. Phase II Enzymes......Page 102
3. Antioxidant Enzymes and Factors......Page 105
4. Steroid Hormone and Protein Biomarkers......Page 107
5. Esterases......Page 110
6. Additional Plasma and Serum Endpoints......Page 112
C. Cellular Biomarkers......Page 113
D. Tissue and Organ System Biomarkers......Page 114
1. Gross Indices......Page 115
2. Histologic Endpoints......Page 116
E. Developmental Indicators......Page 118
1. Bioenergetics: Metabolic Pathways and Regulation of Growth and Reproduction......Page 121
2. Growth......Page 122
3. Reproduction......Page 123
4. Behavior......Page 125
Literature Cited......Page 127
Hepatic, Renal, and Adrenal Toxicology......Page 138
II. Liver Anatomy......Page 139
III. Liver Function in Homeostasis......Page 140
A. Carbohydrate Metabolism......Page 141
B. Lipid Metabolism......Page 142
C. Protein Metabolism and Vitellogenesis......Page 143
IV. Liver Function in Metabolism of Xenobiotics......Page 144
A. Phase I and II Enzymes......Page 145
B. Antioxidant Defense System......Page 147
V. Disease of the Liver......Page 149
VI. Kidney Anatomy......Page 150
A. pH and Ion Balance......Page 151
1. The Renin-Angiotensin and Vasopressin Systems......Page 152
2. Adrenal Functions and Stress......Page 153
C. Hormone Metabolism and Hormone Receptors......Page 154
VIII. Kidney Function in Metabolism of Xenobiotics and in Antioxidant Defense......Page 155
Literature Cited......Page 156
Developmental and Reproductive Effects......Page 164
B. Temperature-Dependent Sex Determination......Page 165
II. Signal Interference: Disrupting a Delicate Developmental Balance......Page 167
A. Developmental Mechanisms......Page 168
1. A Mechanistic Example Using the Reptilian Developmental Model......Page 169
III. A Toxicologic Shift......Page 171
1. No Threshold/Low Doses/Ecologic Relevance......Page 174
3. Considering Mixture Effects During Development......Page 175
4. Developmental Synergy......Page 176
B. Species-Specific Considerations......Page 177
A. Turtles......Page 178
B. Crocodilians......Page 179
C. Squamates......Page 180
V. Future Considerations......Page 181
Literature Cited......Page 182
Neurotoxicology and Behavioral Effects in Reptiles......Page 188
I. Introduction......Page 189
A. Study Design......Page 190
B. Host Differences......Page 193
D. Individual vs. Populations......Page 194
III. Fate to Effects: The Problem with Reptile Studies......Page 195
A. Comparative Neuroanatomy......Page 196
C. From Brain to Behavior......Page 197
A. Neurobehavioral Effects......Page 198
B. Temperature-Dependent Neurobehavioral Effects in Pine Snakes (Pituophis melanoleucus)......Page 199
C. Neurobehavioral Deficits from Lead Exposure in Slider Turtles (Trachemys scripta)......Page 200
D. Other Neurobehavioral Effects That Can Serve as Models......Page 203
A. Summary......Page 204
B. Future Research Needs......Page 205
Acknowledgments......Page 208
Literature Cited......Page 209
Immunotoxicology and Implications for Reptilian Health......Page 214
I. Introduction to the Reptilian Immune System......Page 215
III. Reptilian Immunotoxicology......Page 219
B. Box Turtles......Page 220
1. DDT and Dicofol......Page 221
2. 2,3,7,8-Tetrachlorodibenzo-p-Dioxin......Page 222
3. DDE, TCDD, and Phytoestrogens......Page 223
D. Sea Turtles......Page 225
1. Petrochemicals......Page 226
2. Organochlorine Contaminants......Page 228
3. Heavy Metals......Page 234
4. Fibropapillomatosis......Page 235
IV. Future Directions......Page 237
B. Choosing Reptilian Model Species......Page 238
C. Improving Immune Assessment Tools......Page 239
1. General Considerations......Page 240
2. Hematology Tools......Page 242
3. Innate Immunity Tools......Page 243
4. Acquired Immunity Tools......Page 244
5. Host-Resistance Tools......Page 245
V. Conclusions......Page 246
Literature Cited......Page 247
Reptilian Genotoxicity......Page 256
A. Historical Perspective of Genotoxicity and Genetic Ecotoxicology......Page 257
B. Genotoxic Compounds and Agents in the Environment......Page 258
C. Linking the Mechanism of Genotoxicity with Its Consequences......Page 259
II. The Use of Reptilian Species in the Study of Aquatic and Terrestrial Genotoxicity......Page 261
1. DNA Damage as a Biomarker of Exposure......Page 264
2. Neoplasia as a Biomarker of Effect......Page 266
1. Direct DNA Damage......Page 267
2. Potential Reproductive Impairments......Page 269
3. Potential Immune Suppression......Page 270
1. Tumorigenesis......Page 271
3. Suggestions for Future Models......Page 272
C. Crocodylia......Page 273
IV. Summary......Page 274
Literature Cited......Page 275
Reptile Ecotoxicology: Studying the Effects of Contaminants on Populations......Page 282
A. Ecotoxicology and the Importance of Population Studies......Page 283
B. Why Study Reptiles? Implications for Ecotoxicology......Page 285
C. Properties of Populations......Page 286
D. Impact of Contaminants on Populations......Page 287
A. Life History Strategies......Page 288
B. Life History Strategies of Reptiles......Page 289
1. Clutch Size or Offspring Number......Page 290
3. Frequency of Reproduction......Page 291
A. Separating Effects of Contaminants from Other Factors......Page 293
B. Selecting Appropriate Endpoints......Page 294
C. Unique Aspects of Reptile Populations......Page 295
2. Need for Nondestructive Sampling......Page 296
A. Chelonia (Turtles)......Page 297
1. Freshwater Aquatic Turtles......Page 298
2. Sea Turtles......Page 300
3. Terrestrial Turtles......Page 301
1. Fence and Prairie Lizards (Sceloporus undulatus and S. occidentalis)......Page 302
C. Serpentes (Snakes)......Page 303
2. Garter Snakes (Thamnophis spp.)......Page 304
Literature Cited......Page 305
INDEX......Page 314