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Microbial Biotechnology

Microbial Biotechnology. Chapter 5. The Structure of Microbes. Prokaryotes Archaebacteria Includes halophiles, thermophiles, “extremophiles” Eubacteria On skin, soil, water, can be pathogenic. The Structure of Microbes. Characteristics of Prokaryotes Generally smaller than Eukaryotes

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Microbial Biotechnology

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  1. Microbial Biotechnology Chapter 5

  2. The Structure of Microbes • Prokaryotes • Archaebacteria • Includes halophiles, thermophiles, “extremophiles” • Eubacteria • On skin, soil, water, can be pathogenic

  3. The Structure of Microbes • Characteristics of Prokaryotes • Generally smaller than Eukaryotes • No nucleus • Cell wall composed of peptidoglycan • Conjugation (transfer of DNA by cytoplasmic bridge) • Transduction (DNA is packaged in a virus and infects recipient bacterial cells) • 20 minute growth rate (binary fission)

  4. Yeast are Important Too! • Single celled eukaryote • Kingdom: Fungi • Over 1.5 million species • Source of antibiotics, blood cholesterol lowering drugs • Able to do post translational modifications • Grow anaerobic or aerobic • Examples: Pichia pastoris (grows to a higher density than most laboratory strains), has a no. of strong promoters, can be used in batch processes

  5. Microorganisms as Tools • Microbial Enzymes • Taq (DNA polymerase), cellulases, proteases, amylases

  6. Microorganisms as Tools • Bacterial Transformation • The ability of bacteria to take in DNA from their surrounding environment • Bacteria must be made competent to take up DNA

  7. Microorganisms as Tools • Cloning and Expression Techniques • Fusion Proteins

  8. Microorganisms as Tools • Microbial Proteins as Reporters • Examples: the lux gene which produces luciferase • Used to develop a fluorescent bioassay to test for TB

  9. Microorganisms as Tools • Yeast Two-Hybrid System • Used to study protein interactions

  10. Using Microbes for a Variety of Everyday Applications • Food Products • Rennin used to make curds (solid) and whey in production of cheese • Recombinant rennin is known as chymosin (first recombinant food ingredient approved by FDA)

  11. Using Microbes for a Variety of Everyday Applications • Food Products • Energy production in bacteria • Aerobic or anaerobic

  12. Using Microbes for a Variety of Everyday Applications • Food Products • Fermentation • (anaerobic respiration) • Lactic acid fermentation • Used to make cheese, yogurt, etc. • Ethanol fermentation • Used to make beer and wine

  13. Using Microbes for a Variety of Everyday Applications • Field Applications of Recombinant Microorganisms • Ice-minus bacteria (remove ice protein producing genes from P. syringae) • P. fluorescens containing the gene that codes for the bacterial toxin from Bacillus thuringiensis (kills insects) Bt toxin!

  14. Using Microbes for a Variety of Everyday Applications • Therapeutic proteins • Recombinant insulin in bacteria

  15. Using Microbes for a Variety of Everyday Applications • Using Microbes Against Other Microbes • Antibiotics • Act in a few key ways • Prevent replication • Kill directly • Damage cell wall or prevent its synthesis

  16. Vaccines • First was a vaccine against smallpox (cowpox provides immunity) • DPT-diphtheria, pertussis, and tetanus • MMR –measles, mumps, and rubella • OPV- oral polio vaccine (Sabin)

  17. Vaccines • A Primer on Antibodies • Antigen- foreign substances that stimulate an immune response • Types of leukocytes or white blood cells • B-lymphocytes: antibody-mediated immunity • T-lymphocytes: cellular immunity • Macrophages: “cell eating” (phagocytosis)

  18. Vaccines • Antigens stimulate antibody production in the immune system Light chain Heavy chain IgA – first line of defense IgG and IgM – activates macrophages

  19. Vaccines • Mechanism of Antibody Action

  20. Vaccines • How are vaccines made? • They can be part of a pathogen (e.g. a toxin) or whole organism that is dead or alive but attenuated (doesn’t cause disease) • Subunit (toxin) or another part of the pathogen • Attenuated (doesn’t cause disease) • Inactivated (killed) • What about flu vaccines (why do we have to get a shot every year?)

  21. Recombinant Vaccines • Vaccines – provide immunity to infectious microorganisms Attenuated Vaccine Inactivated Vaccine Subunit Vaccine

  22. Recombinant Vaccines • Recombinant Vaccines • A vaccine produced from a cloned gene Video: Constructing Vaccines

  23. Recombinant Vaccines • DNA vaccines • Direct injection of plasmid DNA containing genes encoding specific antigenic proteins

  24. Bacterial and Viral Targets for Vaccines • HIV

  25. Microbial Genomes • Microbial Genome Program (MGP) –the goal is to sequence the entire genomes of microorganisms that have potential applications in environmental biology, research, industry, and health • Sequencing Strategies

  26. Microbial Genomes • Why study viral genomes? • Decipher genes and their products so that agents that block attachment, block replication can be made

  27. Microbial Diagnostics • Using Molecular Techniques to Identify Bacteria • RFLP • PCR and Real time PCR • Sequencing

  28. Molecular Diagnostics • Application: Molecular Epidemiology • Pulse Net monitors disease outbreaks related to different strains of food-borne pathogens

  29. Microbial Diagnostics • Microarrays for tracking contagious disease • PulseNet used to identify outbreaks

  30. Microbial Diagnostics • Combating Bioterrorism • The use of biological materials as weapons to harm humans or animals and plants we depend on for food • Examples in History • Throwing plague infected dead bodies over the walls of their enemies

  31. Microbial Diagnostics • Using Biotech Against Bioweapons • Postal service x-raying packages • Antibody tests in the field • PCR tests in the field • Protein Microarrays for detecting bioweapon pathogens

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