EBIO 3400 1st Edition Lecture 7Outline of Last Lecture I. Phylogeny of archaea Outline of Current Lecture II. ExtremophilesIII. Methanogens IV. Methane sourcesV. Crenarchaeota VI. ThaumarchaetoaVII. Microbial Nutrition and growth VIII. Uptake of nutrientsIX. How do microbes digest large molecules? Current LectureI. Extremophiles- Retinal based protein, type of phototrophic: organism getting energy from light but not using chlorophyll- Capable of light mediated synthesis of ATP that does NOT involved chlorophyll (using sun’s energy) II. Methanogens- Most studied group on archaea- Generate natural gas= methane- Found in all Anaerobic environments= very diverse habitats (strictly anaerobic) - Making a living by oxidizing hydrogen gas- Very explosive and energy rich- Production of methane is an exergonic reaction meaning the energy can be used to synthesis ATP- Most use carbon dioxide as a carbon source= autotrophs (do not need organic forms of carbon)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.* Why do we care about methanogens and methane? Pretty much everywhere, found in most organisms on the planet in the guts of many organisms- Cows are one of the biggest sources of methane on the planet because of their huge digestive system, trillion of microbes (mostly methanogens) breaking down foodsIII. Methane sources- Methane in the atmosphere à Most have to do with human activity - Human problem that is increasing- Methane is more potent per molecule as a green house gas, a molecule of methane can stay in atmosphere for 12 years, causing more and more feedback as a global warming issue - Key: Methanogensare the direct cause of it but indirectly we are the cause of it because making these environments to live inIII. Crenarchaeota - Extreme thermophiles - Found in deepest parts of the oceans - Extremely diverse - The dominant organisms deep in the ocean are actually crenarchaeota - Huge discovery: archaea are the most dominant organism on the planet because live in such vast areas and the most important because also hard to discover the entire niche that they live in IV. Thaumarchaetoa - Symbiotic relationship with sponges - Found in every environment looked at- Oxidizes ammonia - Very important to nitrogen cycle in oceans and soils V. Microbial Nutrition and growth All life require a source of these 3 things:A. Carbon: heterotrophs and autotrophs B. Energy: phototrophs and chemotrophsC. Electrons: organotrophs and lithotrophsD. Four dominant kinds of organisms: photoautotrophs, chemoheterotrophs, photoheterophs, chemoautotrophs (based on the source of energy and carbon that they use) E. How do microorganisms eat? Have to take everything across their plasma membrane: absorptive feeders-Can only deal with molecules of certain size to get it across their membraneWays of increasing their surface area?1) Increases geometrically, to feed their bodies2) Increase membrane surface areaVI. Uptake of nutrientsVery small molecules (e.g. CO2, O2 can diffuse across the membrane, but most molecules must pass through specialized transporter proteins, permease, porins etc..A. Facilitated diffusion: helps solutes move across a membrane from a region of high concentration to one of lower concentration- Passive (no energy required to do this action) B. Coupled transport systems: are those in which energy released by moving a driving ion down its gradient is used to move a solute up its gradient- Active (require energy) - Symport (travel in same direction)- Antiport (travel in opposite directions) C. APC transporters: found in all three domains of life 2 types:1) Uptake ABC transporters are critical for transporting nutrients2) Efflux ABC transporters are generally used as multidrug efflux pumpsD. Group translocation: is a process that uses energy to chemically alter the substrate during its transport (found in many bacteria) - Phosphate group is being used upVII. How do microbes digest large molecules? Adaptations to eat big things even though they have to bing things across their membranes- Extracellular enzymes- Siderophores: are specialized molecules secreted to bind ferric ion (Fe3+) and transport it into the cell (important for organisms that live in soil, ocean, pathogenicity) - Emulsifying agents (surfactants): eating oil * Microbes release into their surrounding to bind iron, competing with other organism àAlmost all bacteria can do
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