Microorganisms as Model Systems for Studying Evolution (eBook, PDF)

Redaktion: Mortlock, Robert

• Format: PDF

Produktbeschreibung

The microorganisms present on the earth today possess a vast range of metabolic activities and are often able to demonstrate their surprising versatility by gaining both new enzyme activities and new metabolic path ways through mutations. It is generally assumed that the earliest micro organisms were very limited in their metabolic abilities, but as time passed they gradually expanded their range of enzymatic activities and increased both their biosynthetic and catabolic capacity. It is also believed that these primitive microorganisms increased the amount of genetic material they possessed by duplicating their existing genes and possibly by ac quiring genetic material from other organisms. A small group of scientists has been exploring the means by which existing microorganisms are capable of mutating to expand their bio chemical abilities. In recent years, more attention has been focused on this type of research, sometimes called "evolution in a test tube." The recent advances in biotechnology and modern techniques of genetic trans fer have generated new interest in the methods by which a microorgan ism's metabolic activities can be improved or deliberately changed in some specific manner.

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Produktdetails

• Verlag: Springer New York
• Seitenzahl: 326
• Erscheinungstermin: 11. November 2013
• Englisch
• ISBN-13: 9781468448443
• Artikelnr.: 44179125

Inhaltsangabe

1 The Utilization of Pentitols in Studies of the Evolution of Enzyme Pathways.- 1. Introduction.- 2. The Pentitols.- 3. The Utilization of Pentitols by Klebsiella Species.- 4. The Origin of the l-Arabitol Dehydrogenase Activity.- 5. Mutations Improving the Growth Rate on Xylitol.- 6. The Growth of Escherichia Coli Strains on Xylitol.- 7. The Utilization of Xylitol by a Mutant in the Genus Erwinia.- 8. Summary.- References.- 2 Experimental Evolution of Ribitol Dehydrogenase.- 1. Introduction.- 2. Pentitol Metabolism in Klebsiella aerogenes.- 3. Chemostat Culture of Klebsiella aerogenes on Xylitol.- 4. Evolution of Ribitol Dehydrogenase in the Chemostat.- 5. Fluctuating Selective Pressure.- 6. Transfer of the Klebsiella aerogenes Ribitol Dehydrogenase Gene into Escherichia coli K12.- 7. Evolutionary Lessons from the Chemostat Studies.- References.- 3 The Structure and Control of the Pentitol Operons.- 1. Introduction.- 2. The Structure of ?p rbt and ?p rbt dal.- 3. Bipolar Transcription of the Pentitol Operons.- 4. The Pentitol Operon Enzymes.- 5. Substrate Specificity of the Pentitol Operon Enzymes.- 6. rbt Messenger RNA.- 7. DNA Sequencing of the Pentitol Operons.- 8. Translation of the Two Kinases.- 9. Invert Repeat Sequences Enclose the Two Operons.- 10. Structure of an Experimentally Evolved Gene Duplication.- 11. Evolutionary Lessons from the Pentitol Operons.- References.- 4 The Development of Catabolic Pathways for the Uncommon Aldopentoses.- 1. The Structure of the Aldopentoses and Their Occurrence in Nature.- 2. The Pathways of Degradation of Aldopentoses by Coliform Bacteria.- 3. The Biochemical and Genetic Bases for the Establishment of New Enzymatic Pathways for the Degradation of Aldopentoses.- 4. Summary.- References.- 5 Functional Divergence of theL-Fucose System in Mutants of Escherichia coli.- 1. Introduction.- 2. Reversibility of NAD-Linked Reactions.- 3. A Mutant That Uses an NAD-Linked Dehydrogenase to Grow on l-1,2-Propanediol.- 4. Biochemistry of the Fucose System.- 5. Enzymic Changes in the Fucose System in Mutants and Revertants.- 6. Genetic Organization and Regulation of the Fucose System.- 7. Sequential Mutations Changing Propanediol and Fucose Utilization.- 8. Relationship of the Fucose and the Rhamnose Systems.- 9. Conversion of the Fucose System for d-Arabinose Utilization.- 10. Propanediol-Positive Mutants as Evolutionary Vanguards.- 11. Retrospective and Prospective Views.- References.- 6 The Evolved ?-Galactosidase System of Escherichia coli.- 1. Introduction.- 2. Development of the Evolved ?-Galactosidase System as a Tool for Studying Evolution.- 3. Evolution of Multiple Functions for Evolved ?-Galactosidase Enzyme: An Evolutionary Pathway.- 4. Kinetic Analysis of Evolved ?-Galactosidase Enzymes.- 5. Evolution by Intragenic Recombination.- 6. Allolactose Synthesis: Another New Function for Class IV Enzyme.- 7. The Role of Regulatory Mutations in the Evolution of Lactose Utilization.- 8. Directed Evolution of a Repressor.- 9. The Fully Evolved EBG Operon.- 10. A Model for Evolution in Diploid Organisms.- 11. Future Perspectives.- References.- 7 Amidases of Pseudomonas aeruginosa.- 1. Introduction.- 2. Amidase Regulatory Mutants.- 3. Amidase-Negative Mutants.- 4. Mutants with Altered Enzymes.- 5. Properties of Wild-Type and Mutant Amidases.- 6. Amidase Genes and Enzymes.- References.- 8 Structural Evolution of Yeast Alcohol Dehydrogenase in the Laboratory.- 1. Introduction.- 2. The Biochemistry and Regulation of Yeast Alcohol Dehydrogenase.- 3. The Mechanism of Allyl Alcohol Resistance.- 4.Amino Acid Substitutions in the Mutant ADHs.- 5. Altered Kinetics of the Mutants.- 6. Evolutionary Implications.- References.- 9 Gene Recruitment for a Subunit of Isopropylmalate Isomerase.- 1. The Leucine Operon in Salmonella typhimurium Wild-Type Strains.- 2. The Wild-Type Isopropylmalate Isomerase.- 3. Strains Carrying leuD Mutations Revert to Leucine Prototrophy.- 4. Model for Leucine Biosynthesis in leuD-supQ Mutant Strains.- 5. Leucine Biosynthesis in leuD-supQ Mutant Strains.- 6. Genetic Characterization of the leuD-newD Isopropylmalate Isomerase.- 7. Biochemical Characterization of the leuC-newD Isopropylmalate Isomerase.- 8. Theoretical Steps in the Evolution of a Complex Enzyme.- 9. Characterization of the newD (and supQ) Gene(s).- References.- 10 Arrangement and Rearrangement of Bacterial Genomes.- 1. Introduction.- 2. Chromosomal Rearrangements: Mechanisms of Change.- 3. Conservation of Global Gene Order: Mechanisms of Stability.- 4. Conclusion.- References.