Microbiology, Week 1 Notes
Microbiology, Week 1 Notes 81382 - MICR 3050 - 001
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This 8 page Class Notes was uploaded by Amanda Biddlecome on Sunday August 28, 2016. The Class Notes belongs to 81382 - MICR 3050 - 001 at Clemson University taught by Dr. Rudolph in Fall 2016. Since its upload, it has received 10 views. For similar materials see General Microbiology in Biology at Clemson University.
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Date Created: 08/28/16
Microbiology 3050 Amanda Biddlecome August 17, 2016 Chapter 1: The Evolution of Microorganisms and Microbiology 1) What are microorganisms? -‐IN GENERAL, they’re organisms and acellular entities too small to be seen by the naked eye *generally less than or equal to 1mm in diameter *some you can see with the naked eye *some things are microscopic, but aren’t microorganisms because they’re animals -‐often unicellular *don’t have to be part of a multicellular structure to survive *some prefer to live in cell clusters 2) Things Microbiologists Study -‐Fungi, Protists, Bacteria, Archaea *if you don’t have highly differentiated tissue, it’s probably microbial *some people say that mushrooms are microbes *they’re simple in form -‐Acellular *viruses, viroids, satellites, prions ^Hepatitis D. is a satellite, not a virus 3) Importance of Microorganisms -‐they’re in everything -‐1/3 of Nobel prizes have gone to people studying microorganisms -‐microorganisms are the most populous and diverse group of organisms *estimate=5X10 bacteria on Earth 30 -‐found virtually everywhere on the planet *mostly underground! *in environments that nothing else could survive in -‐play a major role in recycling essential elements like nitrogen, carbon, and sulfur *nitrogen fixation -‐major biomass of earth *source of nutrients ^50% of carbon and 90% of nitrogen on earth -‐some do photosynthesis *75% of oxygen came from cyanobacteria and algae -‐most are beneficial, but some can be detrimental (fatal) -‐they influence all other living things -‐excellent tools for study, especially when you can grow them in labs 4) Types of Microbial Cells -‐Prokaryotic=bacteria and archeon *karion-‐means nut *cells without a membrane bound nucleus or membrane bound organelles *simple *not absolute, and there’s always exceptions to these rules *prokaryotes can be very different from one another so grouping is questionable -‐Eukaryotic *membrane bound organelles and nucleus *complex *larger 5) Acellular Infectious Agents -‐viruses *have DNA or RNA *neither prokaryotic nor eukaryotic because they’re not cells *have to have a host cell (parasitic) *causes diseases -‐viroids and satellites *viroids cause plant diseases *satellites cause animal diseases -‐prions *spongiform encephalopathy *mad cow disease *have seen genetic issues caused by this 6) Classification -‐to classify better than just by visuals, look at the DNA in ribosomes in all types of cells *DNA that codes for rRNA *use rRNA DNA because it’s in all cell types -‐3 domain system *know it’s a domain because its capital and italicized -‐constantly changing but the basics are always the same -‐archeons are more closely related to eukaryotes based on DNA sequencing *surprising because they look like bacteria -‐chloroplasts and mitochondria are on the bacteria domain because they have DNA *endosymbiosis hypothesis=they were separate cells that were engulfed by larger cells 7) Domain Bacteria -‐prokaryotic -‐usually 1 cell -‐have peptidoglycan which is a unique polymer found only in bacteria *sugar and amino acid that makes the cell wall -‐can be everywhere *metabolic diversity 8) Domain Archaea -‐prokaryotes -‐different because of unique rRNA sequences, not because of looks -‐have unique membrane lipids to make them more similar to eukaryotes -‐some have unusual metabolic characteristics -‐many live in extreme environments *because they have lipid mono-‐layers for cell membranes that don’t fall apart in heat -‐no evidence that they cause disease 9) Domain Eukarya -‐eukaryotes -‐protists=taxon of mix-‐matched things *all very different *no highly differentiated tissues -‐fungi *no highly differentiated tissues *mushrooms? are they microbes? 10) How did microbes evolve -‐mutation of genes *stable change *mutagen, random, replication complications *could get advantageous phenotype to survive, so natural selection happens -‐Bacteria and Archaea *are haploid: only 1 set of genes *mutation is immediately visible *change happens quicker because they don’t have recessive genes *increase genetic diversity by horizontal gene transfer: pass genes to each other within the same generation, and even between species ^3 types of horizontal gene transfer: conjugation (cell to cell contact through sex pylus with donor and recipient cells), transduction (viruses are the vector, but it’s a mistake by the virus), and transformation (taking naked DNA out of the environment) *increase genetic diversity quickly 11) Microbial Species -‐don’t sexually reproduce *so definition of species is different -‐collection of strains that share stable properties and differ from other groups of strains=microbial species *properties: DNA sequence, GC content, not plasmids *strain=subset of microbial species ^descendants of a single, pure microbial culture ^1 strain becomes the type strain, which is the standard, but sometimes it isn’t the best representation of the species 12) Naming Microbes -‐use domains, genus, species -‐gives a lot of information -‐italicized -‐genus is capitalized and species is lowercased -‐first time you mention it, write out the full name, but after that you can abbreviate the first word (genus) -‐E. Coli *named after discoverer who found it while looking at the feces of infants -‐Bacillus subtilis *slender rod -‐micrococcus luteus *small spheres *golden (bright yellow) -‐streptococcus lactis *chain of spheres *found in milk -‐staphylococcus aureus *staphyl=bunch of grapes *spheres *golden pigment but creamy -‐treponema pallidum *trepo=turn *nema=thread *pallidum=pale -‐saccharomyces cerevisiae *yeast used to make beer *myces means that it has characteristics of fungus 13) Discovery of microorganisms -‐Jansen-‐created first real microscope and it compounded 30 times -‐Hooke (1665) *looked at mold on shoe leather and saw fruiting structures *gets credit for discovering microorganisms because he published it *also discovered cells -‐Leeuwenhoek (1674-‐1676) *sometimes credited with microscope discovery *liked to make magnifying glasses *looked at rainwater with pepper in it *discovered bacteria and drew them and published it *discovered sperm 14) Conflict of Spontaneous Generation -‐spontaneous generation means that organisms can appear out of nothing/nonliving matter -‐Redi (1668) *disproved spontaneous generation of large organisms through his meat/fly experiment 15) Spontaneous Generation Disproved -‐Louis Pasteur *boiled broth in a flask with a curved neck to allow air to get in *dust got stuck in the neck of the flask *flask remains pure to this day, and he disproved spontaneous generation in microorganisms 16) Final Blows to Spontaneous Generation -‐Tyndall (1820-‐1893) *made optically pure air *made a box with glycerine on the inside so dust went in and got stuck *put sterile glass in it and it stayed sterile *said dust carried microorganisms *proposed idea of heat-‐resistant bacteria -‐Cohn *discovered endospores (that’s where Pasteur got lucky) ^very heat resistant *thought all microorganisms were plants *first to use the term bacillus *classified microorganisms by shape 17) The Role of Microorganisms in Disease -‐believed witches cursed people and they got sick -‐had to have right techniques to connect germs to causing diseases *germ theory of disease -‐immunology 18) Indirect Evidence for germ theory of disease -‐Lister *started connecting microorganisms to infection after surgery *Father of Modern Surgery *heat sterilize instruments, poured carboxylic acid sterilizer on wounds, made surgeons wash hands and wear gloves *fewer infections -‐Semmelweis *childbed fever=infection after giving birth *realized doctors and medical students would come directly from studying cadavers to deliver babies ^made them wash hands in chlorine ^didn’t get much credit because he was a jerk and they didn’t want to admit doctors were causing disease 19) Direct Evidence for germ theory of disease -‐Koch=Father of Germ Theory of Disease *looked at anthrax and found out about endospores ^skin contact=20% mortality; ingestion=60% mortality; breathed in=100% mortality *injected anthrax into mice and then their blood into other mice and into the next and etc. *Koch’s Postulates ^still used today ^establishes a link between microorganisms and causing a disease 20) Koch’s Postulates -‐got Nobel Prize for discovering tuberculosis and the microorganism connected to it *used guinea pigs -‐1) find pathogen in ALL cases of disease and in NO healthy subjects *have to visualize bacteria in blood *still could just be a symptom -‐2) isolate the microorganism in a pure culture *use aseptic technique *streak agar plate *spread out sample into quadrant and heat the loop between quadrants *have a colony and know it’s pure culture -‐3) take pure culture and put it into a healthy individual and it should get sick in the same way -‐4) see pathogen in blood and isolate it and should look like the other one -‐limits *techniques *if the only hosts are humans, then you have an ethical dilemma 21) Supplies/Techniques used by Koch -‐agar *jello-‐like substance that solidifies in a Petri dish *gelatin isn’t good because it doesn’t stay solid at body temperature (optimal temperature for growth) *got the idea from a friend’s wife *polysaccharide from seaweed that stays solid at 37 degrees Ce1lcius and bacteria don’t eat it and it can be sterilized and still stay together -‐nutrients *because organisms need to eat *have different nutrient needs for different organisms 22) Developments in Immunology -‐Jenner *vaccination for small pox *300 million people worldwide in the 20th century died of this *did this before the germ theory of disease *from cowpox -‐Pasteur and Roux *incubation of cultures for long intervals causes organisms to weaken and cause immunity, not disease ^attenuation=weakened: age, chemicals *can still stimulate *chicken cholera, rabies, and anthrax vaccines 23) Developments in Industrial Microbiology -‐Pasteur *proved fermentation was done by microorganisms ^bacteria can spoil wine *developed pasteurization ^first done for wine and adapted for milk by Germans ^heat substance to a temperature to kill spoilage microbes but not destroy food: disinfects, not sanitizes -‐Fleming *discovered penicillin *accidental discovery *threw away a culture of staff and later found fuzzy growth that inhibited growth of microbes 24) Developments in Microbial Ecology -‐Winogradsky and Beijerinck *both worked in the same area *used enrichment culture to grow many things ^made them like the environment microorganisms thrive in *selective cultures killed things you didn’t want *studied soil microbes and discovered Nitrogen Fixation -‐Winogradsky: chemolithotrophy *you can use inorganics for an energy source and make organics from carbon dioxide -‐Beijerinck=Father of Virology *started studying viruses
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