Transport in Plants III

The problems associated with the movement of water and solutes throughout the plant body have intrigued students of plants since Malpighi's conclusions in 1675 and 1679 that nutrient sap flows upward and downward in stems through vessels in both wood and bark. Steven Hale's ingenious experiments on the movement of water in plants in 1726 and Hartig's observations of sieve-tube exudation in the mid-19th century set the stage for continued intensive studies on long-range transport in plants. In spite of this interest for more than 200 years in the movement of solutes and water in plants, it has only been within the last 20 to 30 years that extensive research effort has been directed toward a critical evaluation of the interactions among the various cellular organelles. The important roles played by the exchange of metabolites in the control and regulation of cellular processes is now widely recognized, but in most instances poorly understood.

Contenu

I. Membrane Structure.- Plant Membranes.- 1. Introduction.- 2. Isolation of Membranes.- 2.1 Choice of Tissue.- 2.2 Identification of Specific Membranes.- 2.2.1 Microscopy.- 2.2.2 Histochemical Staining.- 2.2.3 Marker Enzymes.- 2.2.4 Antibodies.- 2.3 Tissue Disruption.- 2.4 Membrane Isolation.- 3. Membrane Composition.- 3.1 Membrane Carbohydrates.- 3.2 Membrane Lipids.- 3.3 Membrane Proteins.- 4. Specific Membranes.- 4.1 The Plasmalemma (Plasma Membrane).- 4.1.1 Morphology.- 4.1.2 Chemical Composition.- 4.2 The Nuclear Envelope.- 4.2.1 Morphology.- 4.2.2 Chemical Composition.- 4.3 Plastid Membranes.- 4.3.1 Morphology.- 4.3.1.1 General.- 4.3.1.2 Proplastids.- 4.3.1.3 Etioplasts.- 4.3.1.4 Amyloplasts.- 4.3.1.5 Chromoplasts.- 4.3.1.6 The Higher Plant Chloroplasts.- 4.3.2 Chemical Composition of the Chloroplast Envelope.- 4.4 Mitochondrial Membranes.- 4.4.1 Morphology.- 4.4.2 Chemical Composition.- 4.5 Other Membranes in Plant Cells.- 4.5.1 The Microbody Membrane.- 4.5.2 The Endoplasmic Reticulum Membranes.- 4.5.3 The Golgi Apparatus Membranes.- 4.5.4 The Vacuolar Membrane.- 4.5.5 The Spherosome Membrane.- 5. Membrane Models.- 5.1 The Lipid Bilayer Model.- 5.2 The Unit Membrane Model.- 5.3 Subunit Models.- 5.4 The Lipid-Globular Protein Mosaic Model.- 6. Membrane Structure and Solute Transport.- 6.1 Membranes with Hydrophilic Pores.- 6.2 Carriers and Ionophores.- 6.3 Bridging Proteins Acting as Channels through Membranes.- References.- II. Intracellular Interactions.- 1. Interactions between Nucleus and Cytoplasm.- 1. Old Theories and Present Ideas about the Biochemical Role of the Cell Nucleus.- 2. Experimental Approaches to the Study of Nucleocytoplasmic Interactions.- 2.1 Work on Intact Cells.- 2.1.1 Autoradiography.- 2.1.2 Studies on Chromatin and DNA in Intact Cells.- 2.2 Work on Anucleate Fragments of Unicellular Organisms, Eggs, and Cells.- 2.3 Biochemical Work on Isolated Organelles.- 3. Discussion of Some Recent Experimental Results.- 3.1 Work on Intact Cells.- 3.1.1 Autoradiography.- 3.1.2 Role of the Nuclear Membrane in Nucleocytoplasmic Interactions.- 3.1.3 Choice by the Cytoplasm between DNA Replication and Transcription.- 3.1.4 Effects of the Plasma Membrane on Nuclear Activity.- 3.2 Studies on Anucleate Fragments of Unicellular Organisms, Eggs, and Cells.- 3.2.1 Acetabularia.- 3.2.1.1 Introduction.- 3.2.1.2 Production and Distribution of Morphogenetic Substances.- 3.2.1.3 Energy Production, Circadian Rhythms.- 3.2.1.4 Chloroplastic and Cytoplasmic Protein Synthesis.- 3.2.1.5 Nucleic Acid Synthesis.- 3.2.1.6 Cytoplasmic Effects on the Nucleus.- 3.2.2 Protozoa.- 3.2.3 Eggs.- 3.2.3.1 Sea Urchin Eggs.- 3.2.3.2 Other Eggs.- 3.2.4 Mammalian Cells.- 3.2.4.1 Reticulocytes.- 3.2.4.2 Cells Enucleated with Cytochalasin B.- 4. Conclusions.- References.- 2. Plastids and Intracellular Transport.- 1. Introduction.- 2. The Development of the Experimental Study of Metabolite Translocation in Chloroplasts.- 3. Methods.- 3.1 Distribution in vivo.- 3.1.1 Nonaqueous Techniques.- 3.1.2 Aqueous Separation.- 3.2 Distribution in vitro.- 3.2.1 Centrifugal Filtration.- 3.2.2 Chromatographic Analysis.- 3.3 Indirect Methods.- 3.3.1 Shortening of Induction and Reversal of Orthophosphate Inhibition.- 3.3.2 Catalysis by Intact and Ruptured Chloroplasts.- 3.3.3 Osmotic Volume Changes.- 3.4 Other Aspects of Work with Functional Chloroplasts.- 4. The Site of Sucrose Synthesis.- 5. Starch Synthesis.- 6. The Stimulation of Starch Synthesis in the Light by Exogenous Sugars.- 7. Starch Prints.- 8. The Transport of Metabolites and Coenzymes.- 9. The Transport of Cycle Intermediates.- 9.1 3-Phosphoglycerate and the Triose Phosphates.- 9.2 Pentose Monophosphates.- 9.3 Hexose and Heptose Monophosphates.- 9.4 Sugar Bisphosphates.- 9.4.1 Ribulose-l,5-bisphosphate (RBP).- 9.4.2 Fructose-1,6-bisphosphate(FBP) and Sedoheptulose-l,7-bisphosphate(SBP).- 10. Free Sugars.- 11. C02/Bicarbonate.- 12. Carboxylic Acids.- 12.1 Glycollate and Glyoxylate.- 12.2 Malate and Oxaloacetate.- 13. Amino Acids.- 14. Orthophosphate.- 15. Inorganic Pyrophosphate.- 16. ADP and ATP.- 16.1 Direct Transfer.- 16.2 The Evidence in Favour of Rapid Direct Transfer.- 16.3 The Evidence against Rapid Direct Transfer.- 17. NADP.- 18. Shuttles.- 18.1 The PGA/DHAP Shuttle.- 18.2 The Malate/Oxaloacetate Shuttle.- 19. Specific Transport.- 19.1 ATP Transport.- 19.2 Dicarboxylate Transport.- 19.3 Phosphate Transport.- 20. The Movement of Metabolites in C4 Photosynthesis.- 21. The Movement of Protons and Magnesium.- 22. Concluding Remarks.- References.- 3. Metabolite Carriers of Chloroplasts.- 1. Specific Transport into the Chloroplast.- 2. The Phosphate Translocator.- 3. The Dicarboxylate Translocator.- 4. ATP Transport in Chloroplasts.- References.- 4. Compartmentation and Transport in C4 Photosynthesis.- 1. Introduction.- 2. Radiotracer Kinetics and Compartments.- 3. Inter- and Intracellular Compartmentation of Reactions.- 3.1 Methods.- 3.2 Activities of Isolated Mesophyll and Bundle Sheath Cells.- 3.3 C4 Pathway Enzymes and Their Intercellular Distribution.- 3.4 Intracellular Location of Enzymes.- 3.5 Detailed Schemes for C4 Photosynthesis.- 4. Intercellular Transport in C4 Photosynthesis.- 4.1 Structural Features of the Mesophyll-Bundle Sheath Cell Interface.- 4.2 Intercellular Transport of Metabolite Solutes.- 4.3 Intercellular Transport of CO2 + HCO3?: the CO2 Concentrating Mechanism.- 4.4 Amino Group and Charge Balance during Intercellular Transport.- 5. Intracellular Transport in C4 Photosynthesis.- 5.1 Intracellular Transport in Mesophyll Cells.- 5.2 Intracellular Transport in Bundle Sheath Cells.- 5.3 Organelle Ultrastructure in Relation to Intracellular Transport.- 6. Metabolite Transport in Relation to Chloroplast Photochemical Activities.- 7. Physiological Function of Compartmentation and Transport in C4 Photosynthesis.- References.- 5. Interactions among Organelles Involved in Photorespiration.- 1. Introduction.- 2. Methodology.- 2.1 Measurement of Photorespiration.- 2.1.1 Definitions.- 2.1.2 CO2 Gas Exchange.- 2.1.3 Estimates of Photorespiration by Leaf Models.- 2.1.4 Estimates of Carbon Flux through the Glycolate Pathway.- 2.2 Isolation of Leaf Peroxisomes and Other Cell Organelles.- 3. Glycolate Metabolism and Its Intracellular Compartmentation.- 3.1 Biosynthesis of Glycolate in Chloroplasts.- 3.2 The Glycolate Pathway and Peroxisomes.- 3.3 The Interconversion of Glycine and Serine in the Mitochondria.- 3.4 Glycerate and Its Relationship to Phosphoglycerate.- 4. Glycolate Metabolism in C4-plants, CAM Plants, and Algae.- 4.1 Glycolate Metabolism in C4-plants.- 4.2 Glycolate Metabolism in CAM Plants.- 4.3 Glycolate Metabolism in Algae.- 4.4 Glycolate Metabolism in Blue-Green Algae.- 5. The Transport of Metabolites between Cell Organelles during Glycolate Metabolism.- 5.1 Transport of Glycolate Pathway Intermediates between Peroxisomes, Chloroplasts, and Mitochondria.- 5.2 Sites of CO2 Evolution and O2 Uptake during Photorespiration.- 5.3 Insignificanc…