Carotenoids Volume 4: Natural Functions Edited by G.Britton S.Liaaen-Jensen H.Pfander CH.O Birkhauser
Contents List of Contributors Preface......... xxiv Acknowledgements Editors'Notes xxvi Abbreviations xxviii Chapter 1:Special Molecules,Special Properties George Britton,Synnove Liaaen-Jensen and Hanspeter Pfander A Introduction B.Structure,Properties and Function 2 1.Three-dimensional shape 2 2.The conjugated double-bond system 3.Molecular interactions C.Functions of Carotenoids D.Metabolites and Breakdown Products 6 E.Conclusions 6 Chapter 2:Structure and Chirality Synnove Liaaen-Jensen A.Introduction > B.Three-dimensional Carotenoid Structures 1 C.Methods for Structure Determination.... 9 References 14 Chapter 3:E/Z Isomers and Isomerization Synnove Liaaen-Jensen and Bjart Frode Lutnces A.Introduction 15 B.E/Z Isomers 1 1.Geometrical isomerism:Definition and nomenclature 15 2.Structural examples of common Z isomers 19
v Contents List of Contributors ……………………………………………………..…… xviii Preface …………………………………………………………...…………… xxiv Acknowledgements …………………………………………………………... xxv Editors’ Notes ………………………………………………………………… xxvi Abbreviations ………………………………………………………………… xxviii Chapter 1: Special Molecules, Special Properties George Britton, Synnøve Liaaen-Jensen and Hanspeter Pfander A. Introduction ………………………………………………………………… 1 B. Structure, Properties and Function ……………………………………….. 2 1. Three-dimensional shape ……………………………………………….. 2 2. The conjugated double-bond system ……………………………………. 3 3. Molecular interactions ………………………………….……………….. 4 C. Functions of Carotenoids …………………………………………………... 5 D. Metabolites and Breakdown Products ……………………………………. 6 E. Conclusions …………………………………………………………………. 6 Chapter 2: Structure and Chirality Synnøve Liaaen-Jensen A. Introduction ………………………………………………………………… 7 B. Three-dimensional Carotenoid Structures ……………………………….. 7 C. Methods for Structure Determination ……………………………………. 9 References ……………………………………………………………………… 14 Chapter 3: E/Z Isomers and Isomerization Synnøve Liaaen-Jensen and Bjart Frode Lutnæs A. Introduction ………………………………………………………………… 15 B. E/Z Isomers …………………………………………………………………. 15 1. Geometrical isomerism: Definition and nomenclature …………………. 15 2. Structural examples of common Z isomers ……………………………... 19
3.Physical properties 9 a）Chromatography b)Solubility 20 4.Spectrosc0py… 20 a)UV/Vis spectroscopy 20 b)NMR spectroscopy 21 c)IR and resonance Raman spectroscopy 22 d)Mass spectrometry 22 e)Circular dichroism...... 22 5.Total synthesis 22 C.E/z Isomerization.................. 1.Thermodynamic and kinetic aspects 23 a)Thermodynamic equilibrium 23 b)Reversibility test. 23 c)Kinetically controlled isomerization 24 2.Photochemical isomerization catalysed by iodine 26 a)Conditions for E/Z isomerization 26 b)Conditions for simultaneous E/Z and allenic R/S isomerization...... 3 c)Mechanistic aspects 27 3.Photochemical isomerization catalysed by diphenyl diselenide. 29 a)Conditions 29 b)Thermodynamic equilibrium 29 c)Mechanistic aspects 30 4.Avoiding unwanted E/Zisomerization 31 5.Isolation artefacts. 31 a)Precautions for avoiding E/Z isomerization 31 b)Proof of natural occurrence of cis isomers ....... 31 D.Biological Implications of Carotenoid Z Isomers.... 31 1.Biosynthesis 31 2.Photosynthesis 32 3.Transport,accumulation,and E/Zisomerization in biological tissues a）Human serum....4.. b)Salmonid fishes 33 4.Metabolic conversions 5.Antioxidant properties 34 6.Formation during food and feed processing 4 7.Conclusion… 34 References 34
vi 3. Physical properties ……………………………………………………… 19 a) Chromatography ……………………………………………………. 19 b) Solubility …………………………………………………………… 20 4. Spectroscopy …………………………………………………………….. 20 a) UV/Vis spectroscopy ……………………………………………….. 20 b) NMR spectroscopy …………………………………………………. 21 c) IR and resonance Raman spectroscopy …………………………….. 22 d) Mass spectrometry …………………………………………………. 22 e) Circular dichroism …………………………………………………... 22 5. Total synthesis ………………………………………………………….. 22 C. E/Z Isomerization …………………………………………………………... 22 1. Thermodynamic and kinetic aspects ……………………………………. 23 a) Thermodynamic equilibrium ……………………………………….. 23 b) Reversibility test ……………………………………………………. 23 c) Kinetically controlled isomerization ……………………………….. 24 2. Photochemical isomerization catalysed by iodine ……………………… 26 a) Conditions for E/Z isomerization …………………………………… 26 b) Conditions for simultaneous E/Z and allenic R/S isomerization …… 27 c) Mechanistic aspects ………………………………………………… 27 3. Photochemical isomerization catalysed by diphenyl diselenide ……….. 29 a) Conditions …………………………………………………………... 29 b) Thermodynamic equilibrium ……………………………………….. 29 c) Mechanistic aspects ………………………………………………… 30 4. Avoiding unwanted E/Z isomerization …………………………………. 31 5. Isolation artefacts ……………………………………………………….. 31 a) Precautions for avoiding E/Z isomerization ………………………… 31 b) Proof of natural occurrence of cis isomers …………………………. 31 D. Biological Implications of Carotenoid Z Isomers ………………………… 31 1. Biosynthesis …………………………………………………………….. 31 2. Photosynthesis …………………………………………………………... 32 3. Transport, accumulation, and E/Z isomerization in biological tissues ….. 32 a) Human serum ……………………………………………………….. 32 b) Salmonid fishes ……………………………………………………... 33 4. Metabolic conversions ………………………………………………….. 33 5. Antioxidant properties ………………………………………………….. 34 6. Formation during food and feed processing ……………………………. 34 7. Conclusion ……………………………………………………………… 34 References ……………………………………………………………………... 34
vi Chapter 4:Three-dimensional Structures of Carotenoids by X-ray Crystallography Madeleine Helliwell A.Survey of Previously Reported Carotenoid Crystal Struetures.37 B.New Experimental Methods …41 1.Methods for crystallization of free carotenoids 2.Data collection ....... C.New Determinations of Crystal Structures 43 1.Astaxanthin and related xanthophylls 43 2 Carotenes 49 D.Conclusions 51 References Chapter 5:Aggregation and Interface Behaviour of Carotenoids Sonja Kohn,Henrike Kolbe,Michael Korger,Christian Kopsel,Bernhard Mayer,Helmut Auweter,Erik Liiddecke,Hans Bettermann and Hans-Dieter Martin A.Introduction 53 1.Molecular aggregates 2.Aggregates of carotenoids B.Aggregation in Solution 56 1.Optical and related properties a)UV/Vis spectra 56 b)Geometry of aggregate formation ““+4……+44小+4“+440+4…4小444…*4……4 58 c)Geometry of H-and J-aggregates 61 d)Chirality of aggregates 61 e)Factors that control J-or H-aggregate formation.. 6 f Excited-state dynamics 68 g）)π，r-Stacking interactions 68 h)Emission spectra 2.Light scattering 70 3 Raman spectroscopy C.Aggregation in Different Environments ……4+444……+…44…”*44+*+”…444 3 I.Surfaces and interfaces ......................................................... 73 a)‘Supermicroscopy 73 b)Electrical conductivity of model carotenoids......... 74 c)Bola-amphiphiles 76
vii Chapter 4: Three-dimensional Structures of Carotenoids by X-ray Crystallography Madeleine Helliwell A. Survey of Previously Reported Carotenoid Crystal Structures ………… 37 B. New Experimental Methods ……………………………………………….. 41 1. Methods for crystallization of free carotenoids ………………………… 41 2. Data collection …………………………………………………………. 41 C. New Determinations of Crystal Structures ………………………………. 43 1. Astaxanthin and related xanthophylls …………………………………... 43 2. Carotenes ……………………………………………………………….. 49 D. Conclusions …………………………………………………………………. 51 References ……………………………………………………………………… 51 Chapter 5: Aggregation and Interface Behaviour of Carotenoids Sonja Köhn, Henrike Kolbe, Michael Korger, Christian Köpsel, Bernhard Mayer, Helmut Auweter, Erik Lüddecke, Hans Bettermann and Hans-Dieter Martin A. Introduction ………………………………………………………………… 53 1. Molecular aggregates …………………………………………………… 53 2. Aggregates of carotenoids ……………………………………………… 54 B. Aggregation in Solution ……………………………………………………. 56 1. Optical and related properties …………………………………………... 56 a) UV/Vis spectra ……………………………………………………… 56 b) Geometry of aggregate formation …………………………………... 58 c) Geometry of H- and J-aggregates …………………………………... 61 d) Chirality of aggregates ……………………………………………… 61 e) Factors that control J- or H-aggregate formation .………………….5 66 f) Excited-state dynamics ……………………………………………… 68 g) ,-Stacking interactions …………………………………………… 68 h) Emission spectra ……………………………………………………. 70 2. Light scattering …………………………………………………………. 70 3. Raman spectroscopy ……………………………………………………. 71 C. Aggregation in Different Environments ………………………………….. 73 1. Surfaces and interfaces …………………………………………………. 73 a) ‘Supermicroscopy’ ………………………………………………….. 73 b) Electrical conductivity of model carotenoids ………………………. 74 c) Bola-amphiphiles …………………………………………………… 76
2.Vesicles,lipid bilayers and miscellaneous environments a)Lipid membrane bilayers:phase transitions ............................. b)CD studies 79 c)Surfactant solutions d)Relationship between structure and formation of H-or J-aggregates. 82 e)Some natural examples 0 New applications… 85 3.Influence of additives 4.Natural and artificial nanosized particles containing carotenoids:non- crystalline,crystalline and crystalloidal materials... 87 a)Carotenoid aggregates and crystals in chromoplasts 87 b)Chiral assemblies… c)Primary aggregates and crystals 9 d)Nanodispersions........................................................... e)How natural and artificial assemblies may form 93 References.. Chapter 6:Carotenoid-Protein Interactions George Britton and John R.Helliwell A.Introduction:Interactions of Carotenoids with Other Molecules.......... 99 B.Carotenoid-protein Complexes in Plants and Microorganisms 100 1.Photosynthetic pigment-protein complexes 100 2.Soluble proteins 100 C.Carotenoid-protein Interactions in Animals 101 1.Blood lipoproteins 101 2.Fish muscle 102 3.Feathers 103 D.Carotenoproteins 103 1.General features 103 2.Crustacyanin.... 104 3.The X-ray structure of B-crustacyanin 106 4.The carotenoid-binding site 107 5.Carotenoid-protein interactions 108 6.Mechanism of the spectral shift 112 7.Other carotenoproteins 114 a）Asteriarubin… 114 b)Linckiacyanin 115 c)The carotenoprotein of the Westemn Rock Lobster...................... 115
viii 2. Vesicles, lipid bilayers and miscellaneous environments ………………. 77 a) Lipid membrane bilayers: phase transitions ………………………... 77 b) CD studies …………………………………………………………... 79 c) Surfactant solutions …………………………………………………. 81 d) Relationship between structure and formation of H- or J-aggregates .. 82 e) Some natural examples ……………………………………………... 83 f) New applications …………………………………………………….. 85 3. Influence of additives …………………………………………………… 86 4. Natural and artificial nanosized particles containing carotenoids: noncrystalline, crystalline and crystalloidal materials ………………………. 87 a) Carotenoid aggregates and crystals in chromoplasts ……………….. 87 b) Chiral assemblies …………………………………………………… 89 c) Primary aggregates and crystals ……………………………………. 89 d) Nanodispersions ……………………………………………………. 91 e) How natural and artificial assemblies may form . ………………….. 93 References ……………………………………………………………………… 95 Chapter 6: Carotenoid-Protein Interactions George Britton and John R. Helliwell A. Introduction: Interactions of Carotenoids with Other Molecules ………. 99 B. Carotenoid-protein Complexes in Plants and Microorganisms …………. 100 1. Photosynthetic pigment-protein complexes …………………………….. 100 2. Soluble proteins …………………………………………………………. 100 C. Carotenoid-protein Interactions in Animals ……………………………... 101 1. Blood lipoproteins ………………………………………………………. 101 2. Fish muscle ……………………………………………………………... 102 3. Feathers …………………………………………………………………. 103 D. Carotenoproteins …………………………………………………………… 103 1. General features ………………………………………………………… 103 2. Crustacyanin ……………………………………………………………. 104 3. The X-ray structure of -crustacyanin ………………………………….. 106 4. The carotenoid-binding site …………………………………………….. 107 5. Carotenoid-protein interactions ………………………………………… 108 6. Mechanism of the spectral shift ………………………………………… 112 7. Other carotenoproteins …………………………………………………. 114 a) Asteriarubin ………………………………………………………… 114 b) Linckiacyanin ………………………………………………………. 115 c) The carotenoprotein of the Western Rock Lobster …………………. 115
ix d Crustochrin… 116 e)Ovoverdin 116 f)Ovorubin 116 g)Velellacyanin 116 8.Conclusions-future prospects 117 References 117 Chapter 7:Carotenoid Radicals and Radical Ions Ali El-Agamey and David J McGarvey A.Introduction 119 1.Definitions 119 2.The roles of carotenoid radicals 120 B.Radical Ions 122 1.Formation and detection of carotenoid radical ions .............. 122 a)Pulse radiolysis 122 b)Laser flash photolysis 123 c)Chemical methods 124 d)Electrochemical methods 124 2.Structural and spectroscopic properties of carotenoid radical ions 124 a)Vis/NIR spectroscopy 124 b)Electron paramagnetic resonance (EPR)......... 131 c)Electron nuclear double resonance(ENDOR) 131 d)Resonance Raman spectroscopy.................... 132 3.Reduction(redox)potentials for carotenoid radical ions 132 C.Carotenoid Neutral Radicals 136 1.Formation and detection of carotenoid neutral radicals 136 D.Unidentified Carotenoid Radicals 137 E.Reaction of Carotenoids with Oxidizing Free Radicals ............... 137 1.Factors that influence the mechanism of reactions of free radicals with carotenoids............... 137 2.Free-radical scavenging mechanisms in environments of low polarity .138 3.Free-radical scavenging mechanisms in polar and heterogeneous environments .138 a)Thiyl radicals(RS) 138 b)Sulphonyl radicals(RSO2) 138 c)Peroxyl radicals (RO).......................................... 139 d)Phenoxyl radicals(PhO) 139 e)Other radicals .................................................................... .140
ix d) Crustochrin …………………………………………………………. 116 e) Ovoverdin …………………………………………………………... 116 f) Ovorubin ……………………………………………………………. 116 g) Velellacyanin ……………………………………………………….. 116 8. Conclusions - future prospects ………………………………………….. 117 References ……………………………………………………………………… 117 Chapter 7: Carotenoid Radicals and Radical Ions Ali El-Agamey and David J McGarvey A. Introduction ………………………………………………………………… 119 1. Definitions ………………………………………………………………. 119 2. The roles of carotenoid radicals ………………………………………… 120 B. Radical Ions …………………………………………………………………. 122 1. Formation and detection of carotenoid radical ions …………………….. 122 a) Pulse radiolysis ……………………………………………………... 122 b) Laser flash photolysis ………………………………………………. 123 c) Chemical methods ………………………………………………….. 124 d) Electrochemical methods …………………………………………… 124 2. Structural and spectroscopic properties of carotenoid radical ions …….. 124 a) Vis/NIR spectroscopy ………………………………………………. 124 b) Electron paramagnetic resonance (EPR) …………………………… 131 c) Electron nuclear double resonance (ENDOR) ……………………… 131 d) Resonance Raman spectroscopy ……………………………………. 132 3. Reduction (redox) potentials for carotenoid radical ions ……………….. 132 C. Carotenoid Neutral Radicals ………………………………………………. 136 1. Formation and detection of carotenoid neutral radicals ………………… 136 D. Unidentified Carotenoid Radicals ………………………………………… 137 E. Reaction of Carotenoids with Oxidizing Free Radicals …………………. 137 1. Factors that influence the mechanism of reactions of free radicals with carotenoids ……………………………………………………………… 137 2. Free-radical scavenging mechanisms in environments of low polarity …. 138 3. Free-radical scavenging mechanisms in polar and heterogeneous environments ……………………………………………………………. 138 a) Thiyl radicals (RS ) …………………………………………………. 138 b) Sulphonyl radicals (RSO2 ) ………………………………………… 138 c) Peroxyl radicals (RO2 ) …………………………………………….. 139 d) Phenoxyl radicals (PhO ) …………………………………………… 139 e) Other radicals ……………………………………………………….. 140
F.Reactions of Carotenoid Radicals 44小小小4小 140 1.Carotenoid radical cations (CAR 140 a)Reactions with nucleophiles 140 b)De-protonation 141 c)Reactions with amino acids and peptides 141 d)Reactions with porphyrins ................... 141 e)Reactions with other carotenoids 141 Association with the parent carotenoid 142 g)Reactions with oxygen 143 h)Miscellaneous reactions 143 2.Carotenoid radical anions(CAR) 144 a)Reactions with oxygen. 144 b)Reactions with porphyrins 144 e)Other carotenoids 145 3.Carotenoid neutral radicals 146 a)Unimolecular fragmentation reactions 146 b)Ionic dissociation.. 146 c)Reactions with oxygen 146 G.Antioxidant and Pro-oxidant Properties 147 H.Conclusion...... 150 References 150 Chapter 8:Structure and Properties of Carotenoid Cations Synnove Liaaen-Jensen and Bjart Frode Lutnces A.Introduction 155 B.Carotenoid Oxonium Ions................................ 157 1.Preparation and chemistry 157 2.Vis/NIR spectra 158 C.Delocalized Carotenoid Monocarbocations and Dicarbocations 158 1.Preparation ...... 158 2.Vis/NIR spectra and stability 159 3.Cyclic voltammetry 160 4.AMI calculations 160 5.NMR spectra and structure 160 6.Relation to the soliton model 162 7.Reactions with nucleophiles 163
x F. Reactions of Carotenoid Radicals …………………………………………. 140 1. Carotenoid radical cations (CAR+ ) …………………………………….. 140 a) Reactions with nucleophiles ………………………………………... 140 b) De-protonation ……………………………………………………… 141 c) Reactions with amino acids and peptides …………………………... 141 d) Reactions with porphyrins …………………………………………... 141 e) Reactions with other carotenoids …………………………………… 141 f) Association with the parent carotenoid …………………………….. 142 g) Reactions with oxygen ……………………………………………… 143 h) Miscellaneous reactions …………………………………………….. 143 2. Carotenoid radical anions (CAR ) ……………………………………... 144 a) Reactions with oxygen ………………………………………………. 144 b) Reactions with porphyrins ………………………………………….. 144 c) Other carotenoids …………………………………………………… 145 3. Carotenoid neutral radicals ……………………………………………... 146 a) Unimolecular fragmentation reactions ……………………………… 146 b) Ionic dissociation …………………………………………………… 146 c) Reactions with oxygen ……………………………………………… 146 G. Antioxidant and Pro-oxidant Properties …………………………………. 147 H. Conclusion ………………………………………………………………….. 150 References ……………………………………………………………………… 150 Chapter 8: Structure and Properties of Carotenoid Cations Synnøve Liaaen-Jensen and Bjart Frode Lutnæs A. Introduction ………………………………………………………………… 155 B. Carotenoid Oxonium Ions …………………………………………………. 157 1. Preparation and chemistry ………………………………………………. 157 2. Vis/NIR spectra …………………………………………………………. 158 C. Delocalized Carotenoid Monocarbocations and Dicarbocations ………... 158 1. Preparation ……………………………………………………………… 158 2. Vis/NIR spectra and stability …………………………………………… 159 3. Cyclic voltammetry …………………………………………………….. 160 4. AM1 calculations ……………………………………………………….. 160 5. NMR spectra and structure ……………………………………………... 160 6. Relation to the soliton model …………………………………………… 162 7. Reactions with nucleophiles ……………………………………………. 163
xi D.Carotenoid Radical Cations 163 E.Carotenoid-Iodine Complexes 164 F.Biological Relevance 166 References 166 Chapter 9:Excited Electronic States,Photochemistry and Photophysics of Carotenoids Harry A.Frank and Ronald L.Christensen A.Introduction …167 B.Conceptual Background and Terminology … 168 1.Electronic structure and electronic states 169 2.Electronic transitions 169 3.Interconversions and loss of excitation energy *中94中1中”0卡+04”*卡中””*中49*卡中4“中 171 4.Exciton interactions 171 5.Energy transfer 171 6.Quantum yield 172 C.Absorption Spectroscopy 172 D.Fluorescence Spectroscopy 176 E.Other Optical Techniques and Aspects 178 1.Pump-probe spectroscopy 2.Two-photon spectroscopy 179 3.Resonance Rar nan spectre oscopy 小1 180 F.Experimental Considerations. 181 1.Purity of carotenoids 181 2.Fluorescence spectral corrections 182 3.Band-pass corrections 182 4.Gaussian deconvolution 82 5.Excitation spectra... 18 6.Correlation of absorption and excitation spectra 3 7.Quantum vields................. 184 8.Solvents...... 184 G.Recent Developments........ 185 1.Geometrical isomerization 185 References 186
xi D. Carotenoid Radical Cations ……………………………………………….. 163 E. Carotenoid-Iodine Complexes …………………………………………….. 164 F. Biological Relevance ………………………………………………………... 166 References ……………………………………………………………………… 166 Chapter 9: Excited Electronic States, Photochemistry and Photophysics of Carotenoids Harry A. Frank and Ronald L. Christensen A. Introduction ………………………………………………………………… 167 B. Conceptual Background and Terminology ……………………………….. 168 1. Electronic structure and electronic states ………………………………. 169 2. Electronic transitions …………………………………………………… 169 3. Interconversions and loss of excitation energy ………………………… 171 4. Exciton interactions …………………………………………………….. 171 5. Energy transfer …………………………………………………………. 171 6. Quantum yield ………………………………………………………….. 172 C. Absorption Spectroscopy ………………………………………………….. 172 D. Fluorescence Spectroscopy ………………………………………………… 176 E. Other Optical Techniques and Aspects …………………………………… 178 1. Pump-probe spectroscopy ………………………………………………. 178 2. Two-photon spectroscopy ………………………………………………. 179 3. Resonance Raman spectroscopy ………………………………………... 180 F. Experimental Considerations ……………………………………………… 181 1. Purity of carotenoids ……………………………………………………. 181 2. Fluorescence spectral corrections ………………………………………. 182 3. Band-pass corrections …………………………………………………... 182 4. Gaussian deconvolution ………………………………………………… 182 5. Excitation spectra ……………………………………………………….. 183 6. Correlation of absorption and excitation spectra ……………………….. 183 7. Quantum yields ………………………………………………………….. 184 8. Solvents …………………………………………………………………. 184 G. Recent Developments ………………………………………………………. 185 1. Geometrical isomerization ……………………………………………… 185 References ……………………………………………………………………… 186
Chapter 10:Functions of Intact Carotenoids George Britton A.Functions,Actions and Associations.............. ..189 B.Overview:Diversity of Functions 189 1.Functions involving interactions with light .................. 189 2.Functions not involving interactions with light 191 C.Light harvesting 191 1.Photosynthesis 191 a)Carotenoids and light harvesting 191 b)Protection against excess light energy 3 2.Other light-harvesting roles 193 D.Protection against Oxidative Damage.......................................... 194 1.Photoprotection … 194 2.Singlet oxygen quenching 19 a)Photosensitized by(bacterio)chlorophyll 194 b)Exogenous photosensitizers 195 c)Human erythropoietic protoporphyria 195 d)Singlet oxygen produced non-photochemically 195 3.Protection against oxidizing free radicals(antioxidant action)............ 196 E.Photoreceptors 198 1.Blue-light receptors ........ 198 2.Phototropism and phototaxis 198 a)Phototropism b)Phototaxis 198 F.Vision 199 1.Visual pigments 19g 2.Macular pigments 200 3.Retinal filters:oil droplets. 200 G.Colour 201 1.Pigmentary colours 201 2.Structural colours … 201 3.Colour in plants 202 a)Plant pigments 202 b)Chromoplasts 203 4.Carotenoids in moulds,yeasts and bacteria 203 5.Colour in animals 204 a)Colouration by carotenoids 204 b)Animal pigment cells:chromatophores 204 c)Colour changes 205
xii Chapter 10: Functions of Intact Carotenoids George Britton A. Functions, Actions and Associations ……………………………………… 189 B. Overview: Diversity of Functions …………………………………………. 189 1. Functions involving interactions with light …………………………….. 189 2. Functions not involving interactions with light ………………………… 191 C. Light harvesting ……………………………………………………………. 191 1. Photosynthesis ………………………………………………………….. 191 a) Carotenoids and light harvesting …………………………………… 191 b) Protection against excess light energy ……………………………… 193 2. Other light-harvesting roles …………………………………………….. 193 D. Protection against Oxidative Damage ……………………………………. 194 1. Photoprotection …………………………………………………………. 194 2. Singlet oxygen quenching ……………………………………………… 194 a) Photosensitized by (bacterio)chlorophyll …………………………... 194 b) Exogenous photosensitizers ………………………………………… 195 c) Human erythropoietic protoporphyria ……………………………… 195 d) Singlet oxygen produced non-photochemically ……………………. 195 3. Protection against oxidizing free radicals (antioxidant action) …………. 196 E. Photoreceptors ……………………………………………………………… 198 1. Blue-light receptors ……………………………………………………… 198 2. Phototropism and phototaxis ……………………………………………. 198 a) Phototropism ………………………………………………………… 198 b) Phototaxis …………………………………………………………... 198 F. Vision ………………………………………………………………………... 199 1. Visual pigments ………………………………………………………… 199 2. Macular pigments ………………………………………………………. 200 3. Retinal filters: oil droplets ………………………………………………. 200 G. Colour ……………………………………………………………………….. 201 1. Pigmentary colours ……………………………………………………... 201 2. Structural colours ……………………………………………………….. 201 3. Colour in plants …………………………………………………………. 202 a) Plant pigments ………………………………………………………. 202 b) Chromoplasts ……………………………………………………….. 203 4. Carotenoids in moulds, yeasts and bacteria …………………………….. 203 5. Colour in animals ……………………………………………………….. 204 a) Colouration by carotenoids …………………………………………. 204 b) Animal pigment cells: chromatophores …………………………….. 204 c) Colour changes ……………………………………………………… 205
xi H.Carotenoids in Membranes .205 1.Membrane structure 205 2.Localization and orientation of carotenoids.......................... 206 3.Effects of carotenoids on membrane structure and properties 207 4.Reinforcement of bacterial membranes.......... 208 5.Protection of membranes against oxidizing free radicals 209 6.Membrane-associated processes 209 7.Zeaxanthin in thylakoid membranes ..................................... 209 I.Fertility and Reproduction 209 J.Miscellaneous Proposed Functions ..... 210 K.Breakdown Products and Metabolites 210 L.Carotenoids in Human Health and Nutrition 211 References 211 Chapter 11:Signal Functions of Carotenoid Colouration Jonathan D.Blount and Kevin J.MeGraw A Introduction 213 1.Biological signals and their reliability 213 2.Carotenoids as signals... 214 B.Carotenoid Signals in Plants 214 I Frits and flowers 214 2.Leaves 216 C.Carotenoid Signals in Animals 217 1.Signalling to other species(heterospecifics) 217 a)Species recognition 217 b)Warning (aposematic)colouration and mimicry 218 c)Crypsis 219 2.Signalling to members of the same species (conspecifics)............... 221 a)）Sexual signalling 221 b)Social status signalling............................................... 223 c)Parent-offspring signalling 223 d)Other conspecific signal functions 224 D.Information Content of Carotenoid Signals 224 1.Nutritional state 224 2 Parasite load 226 3.Immune defence 227 4.Antioxidant activity 。。 227
xiii H. Carotenoids in Membranes ………………………………………………... 205 1. Membrane structure …………………………………………………….. 205 2. Localization and orientation of carotenoids …………………………….. 206 3. Effects of carotenoids on membrane structure and properties ………….. 207 4. Reinforcement of bacterial membranes ………………………………… 208 5. Protection of membranes against oxidizing free radicals ………………. 209 6. Membrane-associated processes ………………………………………... 209 7. Zeaxanthin in thylakoid membranes ……………………………………. 209 I. Fertility and Reproduction …………………………………………………. 209 J. Miscellaneous Proposed Functions ………………………………………… 210 K. Breakdown Products and Metabolites ……………………………………. 210 L. Carotenoids in Human Health and Nutrition …………………………….. 211 References ……………………………………………………………………… 211 Chapter 11: Signal Functions of Carotenoid Colouration Jonathan D. Blount and Kevin J. McGraw A. Introduction ………………………………………………………………… 213 1. Biological signals and their reliability ………………………………….. 213 2. Carotenoids as signals ………………………………………………….. 214 B. Carotenoid Signals in Plants ………………………………………………. 214 1. Fruits and flowers ………………………………………………………. 214 2. Leaves .………………………………………………………………….. 216 C. Carotenoid Signals in Animals …………………………………………….. 217 1. Signalling to other species (heterospecifics) ……………………………. 217 a) Species recognition …………………………………………………. 217 b) Warning (aposematic) colouration and mimicry …………………… 218 c) Crypsis ……………………………………………………………… 219 2. Signalling to members of the same species (conspecifics) …………….. 221 a) Sexual signalling ……………………………………………………. 221 b) Social status signalling …………………………………………….. 223 c) Parent - offspring signalling ………………………………………… 223 d) Other conspecific signal functions …………………………………. 224 D. Information Content of Carotenoid Signals ……………………………… 224 1. Nutritional state …………………………………………………………. 224 2. Parasite load …………………………………………………………….. 226 3. Immune defence ………………………………………………………… 227 4. Antioxidant activity …………………………………………………….. 227