Microbio 310 1st EditionExam # 1 Study Guide Lectures: 1 - 9Lecture 1 (January 21)Griffith’s Transformation Experiment- Mouse injected with living S strain bacteria (virulent)o Mouse dies of pneumonia- Mouse injected with living R strain bacteria (nonvirulent)o Mouse lives- Boil/kill S strain bacteriainject into mousemouse alive- Mix dead S strain with living R straininject into mouseMouse dies by pneumonialiving S strain found in heart- DNA carrying genes for capsule production is released from dead S cells and taken up by R cells, thus transforming them into S cells. - DNA=transforming factor- Conclusion: chemical substance from one cell capable of genetically transforming another cellMRSA- shows that antibiotic resistance is inevitable1.1 The Science of Microbiology - Microbiology has two major themes: 1.Understanding basic life processes2.Applying that knowledge to the benefit of humans• The Importance of Microorganisms:– Oldest form of life– Largest mass of living material on Earth– Carry out major processes for biogeochemical cycles– Can live in places unsuitable for other organisms – Other life forms require microbes to survive (i.e. humans)Lecture 2 (January 23) 1.2 Microbial Cells• Characteristics of Living Systems– Metabolism: chemical transformation of nutrients– Reproduction: generation of two cells from one– Differentiation: synthesis of new substances or structures that modify the cell (only in some microbes)– Communication: generation of, and response to, chemical signals (only in some microbes)– Movement: via self-propulsion, many forms in microbes– Evolution: genetic changes in cells that are transferred to offspring- Properties of all cells:- Compartmentalization- Metabolism- Growth - Evolution - Properties of some cells:- Motility- Differentiation (i.e. forming spores)- Communication (Quorum sensing)1.3 Microorganisms and Their Environments• Microorganisms exist in nature in populations of interacting assemblages called microbial communities • Microbial ecology = study of microbes in their natural environment• Diversity and abundances of microbes are controlled by resources (nutrients) and environmental conditions (i.e., temp, pH, O2)• Microbes also interact with their physical and chemical environment– Ecosystems are greatly influenced/controlled by microbial activities– Microorganisms change the chemical and physical properties of their habitats through their activities (removal of nutrients from the environment and the excretion of waste products)1.4 Evolution and the Extent of Microbial Life• The First Cells– First self-replicating entities may not have been cells (catalytic RNAs)– Last universal common ancestor (LUCA): common ancestral cell from which all cells descended• Life on Earth 4.6 billion years old– First cells appeared between 3.8 and 3.9 billion years ago– The atmosphere was anoxic (=no oxygen) until ~2 billion years ago– Anaerobic until evolution of oxygen-producing phototrophs– Life was exclusively microbial until ~1 billion years ago• The Extent of Microbial Life– Microbes found in almost every environment imaginable o Most microbial cells are found in oceanic and terrestrial subsurfaces– Microbial biomass is significant and cells are key reservoirs of essential nutrients (e.g., C, P, N)Lecture 3 (January 26)1.5 The Impact of Microorganisms on Humans• Microorganisms can be both beneficial and harmful (infectious disease agents) to humans; more are beneficial than harmful• Microorganisms and Agriculture• Positive impacts– Nitrogen-fixing bacteriaconvert N2 into nitrites/nitrates– Cellulose-degrading microbes in the rumen (stomach compartment of cows)– Regeneration of nutrients in soil and water• Negative impacts– Diseases in plants and animals• Microorganisms and Food – Negative impacts• Food spoilage by microorganisms requires specialized preservation of many foods– Positive impacts• Microbial transformations (typically fermentations) yield:– dairy products (e.g., cheeses, yogurt, buttermilk)– other food products (e.g., sauerkraut, pickles, leavened breads, beer)• Microorganisms, Energy, and the Environment– The role of microbes in biofuels production (ex: methane, ethanol, hydrogen)– The role of microbes in cleaning up pollutants (bioremediation)• Microorganisms and Their Genetic Resources – Exploitation of microbes for production of antibiotics, enzymes, and various chemicals– Genetic engineering of microbes to generate products of value to humans, such as insulin (biotechnology)o Uses recombinant DNAgenetically modified organisms (GMO)1.6 The Historical Roots of Microbiology• Microbiology began with the microscope• Robert Hooke: the first to describe microbes• Antoni van Leeuwenhoek: the first to describe bacteria • Ferdinand Cohn: founded the field of bacterial classification and discovered bacterial endospores1.7 Pasteur and the Defeat of Spontaneous Generation• Louis Pasteur – Discovered that living organisms discriminate between optical isomers– Discovered that alcoholic fermentation was a biologically mediated process (involves living organisms); originally thought to be purely chemical– Disproved theory of spontaneous generation through swan-necked flask experimento In such a flask nutrient solutions could be boiled and sterilized. After the flaskwas cooled, air was allowed to reenter, but the bend in the neck prevented particulate matter, including microorganisms, from entering the nutrient solution and causing putrefaction. As a result the solution remained sterile. If the flask was tipped particulate matter and microorganisms would enter the sterile liquid.• Led to the development of methods for controlling the growth of microorganisms (aseptic technique)– Developed vaccines for anthrax, fowl cholera, and rabies1.8 Koch, Infectious Disease, and the Rise of Pure Cultures• Robert Koch – Demonstrated the link between microbes and infectious diseases• Identified agents that cause anthrax and tuberculosis– Developed techniques (solid media) for obtaining pure cultures of microbes, some still in existence today– Koch’s postulates:- Used to prove cause and effect in infectious diseases. - Used to definitively link a specific microorganism to a specific disease 1. The suspected pathogen must be present in all cases of the disease and absent from healthy animals.2. The suspected