General Microbiology MIP 300
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This 14 page Class Notes was uploaded by Winona McClure on Tuesday September 22, 2015. The Class Notes belongs to MIP 300 at Colorado State University taught by Erica Suchman in Fall. Since its upload, it has received 29 views. For similar materials see /class/210242/mip-300-colorado-state-university in Microbiology at Colorado State University.
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Date Created: 09/22/15
23 January Extra Credit Start of class clicker points 10 days mostly Fridays if you get the answer correct you can get 1 point of XC total 10 If you do not miss more than 2 classes you can get 5 points of XC all or nothing 0 or 5 I will know you were here if you click at some point during class Microbucks bring news stories with short write up 2 chosen per day up to 10 points Turned in with exams Bloom s Taxonomy Levels of thinking Remembering 9 understanding 9 applying 9 analyzing 9 evaluating 9 creating Who are the microbes Sizes of microbes 100 um 001 pm Too small to be seen without a microscope Types of microbesbranch of microbiology Prokaryotes Bacteria amp archaebacteriabacteriology No nucleus or other membrane bound organelles 1000s of species Archeabacteria ancient bacteria Eukaryotes fungi protozoa algae Have nucleus and other membrane bound organelles including golgi apparatus mitochondria endoplasmic reticulum lysosomes Neither prokaryotic nor eukaryotic virusesvirology prions Big debate Are they even alive Obligate intracellular parasites can only reproduce inside host cells Have no cells or cell membrane Don t grow No nutritional needs Interesting fact 75 of the 80 new diseases discovered between 1980 and 2007 are RNA viruses How do we classify microbes 5 kingdom system vs 3 Domain 5 Kingdoms Monera true prokaryotes bacteria archea Protista protozoa and single celled algae Fungi yeast molds fungi mushrooms Plantae photosynthetic plants Animalia animals 3 Domains Bacteria Archea Eukarya Note viruses and prions not currently in a kingdom or domain Both systems The most basic raking is species 2 higher organisms same species if they can mate and produce offspring which can mate Bacterial species groups of strains that have many stable properties in common and differ significantly from other strains Within species there are strains races breeds etc In microbes strains Study Habits How to do well in MP300 Don t try to memorize material Learn how to think about microbiology Learn to use the information you know Learn how to explain what you know to others Get into a study group Study with them regularly Use the study guide questions talk about the questions 28 January Eubacteria cell membranes Membranes are an absolute requirement for all living cells both eukaryotic and prokaryotic Functions Selectively permeable barrier Nutrient and waste transporter Location of metabolic processes photosynthesis oxidative phosphorylation and chemotaxis receptors Components Phospholipid bilayer Phosphotidylethanoloamine Hapanoids Similar to the steroids found in eucaryotes Function stabilize membranes Proteins and glycoproteins Peripheral proteins Integral proteins Glycoproteins covalently attached oligosaccharides either peripheral or integral Functions of membrane proteins Nutrient and waste transport into and out of cell Carry out metabolic processes photosynthesis oxidative phosphorylation Chemotaxis receptors This model of membrane structure is called the fluid mosaic model Eubacteria envelope the cell wall Envelope consists of all structures outside of plasma membrane Most bacteria except mycoplasmas and a few archeobacteria contain a cell wall Except for mycobacterium bacteria have either Gram or cell wall waxy layer of mycolic acid inhibits good staining Functions of cell wall Gives cell shape Protection from osmotic pressure Most bacteria live in a hypotonic environment less solutes in environment than cell osmosis water would rush in break cell Protection from toxic substances Gram envelope Plasma membrane Large periplasmic space between plasma membrane and outer membrane Large of periplasmic enzymes involved in nutrient acquisition permeases hydrolytic enzymes 1 7 nm thick peptidoglycan layer Outer membrane or lipopolysaccharide layer LPS layer Oligosaccharide attached to phospholipid Porin proteins allow small molecules to pass more permeable than plasma membrane Larger molecules transported by permeases Helps avoid immune defenses Barrier to toxic substances Holds in periplasmic enzymes Contains endotoxins released when bacteria die This makes it hard for the immune system to deal with Causes drop in blood pressure Gram envelope Plasma membrane Very small periplasmic space between plasma membrane and cell wall Small of periplasmic enzymes involved in nutrient acquisition permeases hydrolytic enzymes 20 80 nm thick peptidoglycan or murein layer cell wall contains teichoic acids function unclear Large of secreted exoenzymes enzymes that would be periplasmic in Gram bacteria No endotoxins Easier to kill Components of peptidoglycan Gram and Carbohydrates NAG Nacetylglucosamine NAM Nacetylmuramic acid Amino acids tetrapeptide Lalanine Dglutamic acid MesoDAP or Llysine Dalanine Gram bacteria other amino acids Structure of peptidoglycan Very large molecule of repeating units Backbone ofalternating NAG and NAM Tetrapeptide Lala Dglu MDAP Dala attached to NAM Peptidoglycan sheets are attached by crosslinks between tetrapeptides Gram bacteria two tetrapeptides from different sheets bind directly Gram bacteria other amino acids form interbridge between tetrapeptides What accounts for differences in thickness in Gram sheets NAGNAM tetrapeptide amino acids in interbridge Type amino acids in interbridge What accounts for differences in thickness in Gram of sheets Gram staining bacteria Primary stain crystal violet Mordant Grams iodine binds crystal violet Decolorizer acetone or ethanol Gram retain crystal violetiodine complex purple Gram do not colorless Secondary stain Safranin red Turns Gram red 25 January Properties of light When rays of light pass from one medium to another ie air to H20 the rays bend refraction Refractive index measure of how greatly a substance slows the velocity of light Amount and direction of bending are determined by the refractive indices of the interfacing substances 4 Types of Light Microscope Magnification objective eyepiece 40x objective 10x eyepiece 400x magnification Ability of lens to distinguish between objects is resolution or resolving power Best light microscope resolution 02 pm Bacteria 1 pm diameter Only used to see shape size and arrangement Viruses 001 01 pm too small to see with light microscope Brightfield microscopy Must stain bacteria Background appears light bacteria are color of stain Darkfield microscopy Light is refracted by organism enters objective Background appears dark organism appears bright Good for looking at things that are still alive Phase contrast microscopy Phase contrast converts slight differences in refractive indices into easily detected variations in light intensity Internal structures Fluorescent microscopy uses a UV light to excite fluorescent molecules such as Green Fluorescent proteins or labeled antibodies Staining microbes for brightfield microscopy Before staining microbes must be quotfixedquot to slide Usually using heat or chemicals Simple stain 1 stain used to increased microbes visibility Determine shape size and arrangement Differential stains divides microbes into different categories depending on staining properties Gram stain separates bacteria by the type of cell wall they have or purplepink Antibiotics work differently Broad spectrum kills both and but disrupts normal flora Acid fast stain identifies bacteria that are neither gram nor Have a thick waxy layer mycolic acid around them These are mycobacteriums Tuberculosis and leprosy Endospore staining identifies spore producing bacteria Pink cells green endospores Flagella stain identifies bacteria that possess flagella used for motility Electron microscopes Resolution 1000x better than light microscope 5 x 10 40005 um resolution Size bacteria gt virus gt prion Shapes and arrangements Cocci s coccus round spherical Diplococci divide and remain together pairs Streptococcus divide and remain together long chains Staphylococcus divide in random places grape like clusters Tetrads divide in 2 planes 4 cell groups Sarcina divide in 3 planes 8 cell groups Bacilli s Bacillus rods Different length to width ratio different ends flat round Coccobacillus short and wide Resemble cocci Diplobacilli divide and remain together pairs Streptobacillius divide and remain together long chains Vibrius curved rods commas Cholera Spirals long rods twisted into corkscrews Spirilla corkscrew with flagella Spirochete corkscrew no external flagella Syphilis Pleomorphic lacking a characteristic shape Prokaryotic cell organization Note not all structures are found in every genus 30 January Eubacteria cytoplasmic structures Cytoplasmic matrix contained by plasma membrane 70 water 30 enzymes salt lipids nucleic acids etc Unlike eukaryotes no lipid bilayer bound organelles May contain storage vesicles inclusion bodies Not bound by lipid bilayer membranes bound by membranes of protein simple lipid or no membrane Types of inclusions can be used to help characterize bacteria Organic Inclusion Bodies Glycogen granules glucose energy source Cyanophycin granules long chains of amino acids Arginine and aspartic acid Nitrogen storage Carboxysomes enzymes involved in C02 fixation C02 9 sugar Gas vacuole small proteins Trap gas allow bacteria to float Collapse to sink Build new ones to float Inorganic Inclusion Bodies Metachromatic granules store phosphate used to promote nucleic acids and ATP Magnetasomes contain iron align bacteria in Earth s magnetic field More food closer to surface Bacteria contain many free ribosomes Synthesize proteins Eucaryotes most ribosomes on endoplasmic reticulum Procaryotic mitochondrial chloroplastic ribosomes smaller than eukaryotic ribosomes Bacteria contain 1 circular DNA chromosome Eucaryotes have 2 or more chromosomes contained within a lipid bilayer nucleus Eukaryote DNA wrapped around histone proteins prokaryotic is not Bacteria may contain plasmids Small circular pieces of dsDNA 2 15 kbases Can either integrate into chromosome or replicate independently Not required for host growth and reproduction May confer selective advantages to bacteria that possess them Antibiotic resistance New metabolic processes Antibacterial toxins Toxins to make them more pathogenic Procaryotic endospores Spore forming genera all Gram Clostridum Bacillus Sporosarcina Famous spore forming diseases Bacillus Anthrax cutaneous ingestion inhalation Food poisoning Clostridium Botulism causes flaccid paralysis infantile is most common honey die from lack of O2 Tetanus causes rigid spastic paralysis die from lack of Oz Gas gangrene problem with diabetes fingerstoes are numb cuts go unnoticed and get infected gas bubbles form Have different locations within sporangium aid in classification Central Terminal Subterminal Termianl with swollen sporangium Pink cell green spore Structure Dehydrated core 15 calcium dipicolinic acid Ribosomes and nucleic acids Surrounded by thick layer of peptidoglycan cortex and many layers of protein spore coats Form within sporangium Resistant to heat ultraviolet radiation chemical disinfectants dehydration Triggered by starvation Can remain viable hundreds of years If stained with endospore stain can be visualized under light microscopes Heat resistance Calciumdipicolinic acid stabilization of DNA Core dehydration Sporulation Occurs due to lack of food 7 steps 10 hours Germination 3 steps Activation triggered by heating Germination triggered by food Outgrowth protoplast makes new cell components vegetative ce emerges from spore Not a reproductive process 1 sporangium 9 1 spore 9 1 vegetative ce