EBIO 3400 1st Edition Lecture 8Outline of Last Lecture I. Extremophiles Outline of Current Lecture II. EmulsifiersIII.Extracellular EnzymesIV. Growth V. IntroductiontoMutationsVI. Filamentous bacteria and fungi growth VII. Microbial population growthCurrent LectureI. EmulsifiersVery common in microbesImportant for degrading oil and other hydrophobic substances- Bacteria are making natural detergents that break up the oil smaller droplet that they can attach to and can digest - Ex: Rhodococcussp.A. Two roles for microbial emulsifiers have been proposed1) Increasing surface area of hydrophobic growth substrates 2) Increasing their apparent solubility or desorbing them from surfaces(Don’t need to know the organic structures of these things)II. Extracellular enzymesEnzyme SubstrateA. Proteases ProteinsB. Ig-proteases Immunoglobulin (antibodies) C. Amylases StarchD. Cellulases Cellulose E. Penicillin amidase PenicillinEx: Bacillus Subtilis hydrolysis of starch (degrade/eat/digest starch) 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.- Use extracellular enzymes to degrade starch to oligosaccharides for transport across the outer membrane- Extremely important process in gut when breaking down starchIII. Growth-One microbial cell can't make a difference - takes millions of cells per ml or cc to cause any sort of effect. One cell of the most virulent microbe on the planet cannot hurt you- Importance of growth in medicine and the environment.. Microbes express different genes when they have grown to high densities - they sense there degree of crowdedness usingA. Growth of single-celled prokaryotes1) Growth and reproduction - Bacteria basically clone themselves when they reproduce via binary fission (Simply shaped organisms often break into two identical daughter cells (clones of mother cell)2) Other microbes reproduce asymmetrically….Budding off of smaller cells (e.g. yeast, Planctomycetes, Hyphomicrobium3) Binary fission: longest step is the DNA duplicating IV. Filamentous bacteria and fungi growth Grow via extension of the hyphal tip- Fungi: growth is supplied by vesicles- Fungi and actinobacteria also reproduce via spores = hyphal growth followed by fragmentation in Actinobacteria- Spores germinate into filamental strands A. Growth of a filamentous fungus (a lot of bacteria do this too)Spore germ tube hypha Mycelium V. Microbial population growth- Microbial populations grow exponentially when supplied with enough nutrients- The time it takes to divide is called the generation time (g) also called doubling time- Exponential (log) growth of
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