Ch.11 Prokaryotes PDF

Ch.11 - Prokaryotes Streptococcus pyogenes o infrequent, but usually pathogenic, part of the oral flora. pathogenic strains: o pharyngitis - inflammation of the pharynx...

Ch.11 - Prokaryotes Streptococcus pyogenes o infrequent, but usually pathogenic, part of the oral flora. pathogenic strains: o pharyngitis - inflammation of the pharynx o severe invasive infections o necrotizing fasciitis - flesh-eating disease o yearly lethal S. pyogenes infections: 10%–30% Streptococcus pyogenes necrotizing fasciitis of leg from S. pyogenes  Ch.11 – Prokaryotes o Classifying bacteria o Non-proteobacteria bacterioides, anoxygenic photosynthesizers, spirochetes, chlamydia o Proteobacteria anoxygenic / oxygenic photosynthesizers, enterobacteriaceae, pathogenic proteobacteria o Gram positive bacteria firmicutes and actinobacteria o Prokaryotic diversity  Ch. 11 – Learning Outcomes: 1. Distinguish proteobacteria from non-proteobacteria. 2. Describe and discuss the different groups of non-proteobacteria. 3. Describe the unique cell traits of pathogenic spirochetes. 4. Describe and discuss the different groups of proteobacteria. 5. Explain how cyanobacteria support the life of all animals on Earth, including humans. 6. Summarize the group enterobacteriacae and discuss their importance to human health. 7. Distinguish the two phyla of Gram-positive bacteria. 8. Identify unique traits and characteristics of fimicutes and actinobacteria. 9. Describe the diversity of bacteria associated with both the environment and the human body.  Amazing Prokaryotes! evolution of bacteria and archaea oldest life form – 3.5 billion years old! 30 phyla of bacteria from which species can be cultured in the laboratory it’s estimated there may be over 1,000 more phyla we have yet to see! there are around 40 million bacteria in a gram of soil  Phylogenetic Relationships of Prokaryotes evolution of bacteria and archaea prokaryotic species: population of cells with similar genotypic / phenotypic characteristics species are ultimately distinguish by differences in their DNA or rRNA sequences. strain (serovar or serotype): genetically different cells within species population genetic variants (or subtypes) within species  prokaryotic classification and grouping: evolution of bacteria and archaea Bacteria: Archaea: 1st living organism archaea evolved in an exclusively “pre-oxygen gram negative evolved 1st atmosphere” gram positive latest evolving bacteria all are extremophiles bacteria can be aerobic or anaerobic all are obligate anaerobes wide range of environmental niche’s all non-pathogenic: no disease causing many are extremophiles archaea have been discovered!  evolution of bacteria and archaea shapes and arrangement some major bacterial groups: o bacteroides - 1st bacteria o phyla proteobacteria gram negative rods; obligate anaerobes gram negative aerobic and facultative anaerobes o photosynthetic bacteria o chlamydias sulfur / non-sulfur (purple or green) - anoxygenic intra-cellular parasitic bacteria cyanobacteria: oxygenic o gram positive o spirochetes latest evolutionary bacterial group many pathogenic species 2 phyla - firmicutes and actinobacteria  Ch.11 – Prokaryotes o Classifying bacteria o Non-proteobacteria bacterioides, anoxygenic photosynthesizers, spirochetes, chlamydia o Proteobacteria anoxygenic / oxygenic photosynthesizers, enterobacteriaceae, pathogenic proteobacteria o Gram positive bacteria firmicutes and actinobacteria o Prokaryotic diversity  non-proteobacteria vs. proteobacteria - two broad groupings of gram-negative bacteria Proteus mirabilis spirochaetes peritrichous flagella non-proteobacteria: bacteroides, photosynthetic, spirochetes and chlymidia’s proteobacteria: all gram negative; most rods; most obligate anaerobes also all gram negative; all rods include anoxygenic photosynthetic bacteria most facultative anaerobes or obligate aerobes o purple sulfur / non-sulfur bacteria (anoxygenic) great diversity (>30% of all known bacteria) o obligate anaerobes many pathogenic species (Shigella; Salmonella) include chemoheterotrophes cyanobacteria – oxygenic photosynthesis o obtain energy from organic compounds green sulfur / non-sulfur bacteria (anoxygenic) o spirochetes (motile); bacteroides (non-motile); oxygen tolerating (aerotolerant anaerobe) chlamydia (non-motile; intracellular) contain nitrogen fixing species contain nitrogen fixing species  four non-proteobacteria groups: 1. Bacteroides 2. Purple sulfur / non-sulfur purple sulfur bacteria Bacteroide fragilis resident gut microbiota 3. Spirochetes 4. Chlamydia Borrelia burgdorferi Treponema pallidum Chlamydophila psittaci inside a cell lyme disease syphilis  bacteriodes Bacteroide fragilis Gram negative rod obligate anaerobe normal colon microbiota bacteroides - the 1st bacteria all obligate anaerobes major inhabitants of the human colon ferment indigestible sugar derivatives break down toxins produce communication molecules (polysaccharide A) – directs innate immune response  purple sulfur and non-sulfur bacteria obligate anaerobes anoxygenic photosynthetic bacteria o carry out anoxygenic photosynthesis – using electron donor that IS NOT H2O o light + CO2 + H2S = C6H12O6 + 2S purple sulfur bacteria (anaerobic environment) uses H2S instead of H2O as electron donor for photosynthesis produce sulfides instead of oxygen purple sulfur bacteria absorb higher energy wavelengths than green sulfur bacteria purple non-sulfur bacteria (micro-aerobic environments) uses organic H source instead of H2S or H2O as electron donor absorb higher energy wavelengths than green non-sulfur bacteria *Notes* “green” and “purple” named for different wavelengths used with photosynthesis sulfur bacteria are obligate anaerobes or microaerophiles salt marsh pool - Woods Hole, non-sulfur bacteria can tolerate aerobic environments Massachusetts  spirochetes Treponema pallidum syphilis – sexually transmitted genital disease yaws yaws – tropical infection (skin and bones) bejel (endemic syphilis) – chronic skin and tissue disease spirochetes spiral shape coiled and move via axial filaments (endoflagella) many pathogenic: syphilis, yaws, bejel, relapsing fever, lyme disease, leptospirosis can literally “drill” through your skin/tissues! secondary syphilis bejel  Chlamydia Chlamydophila psittaci in host cell obligate intracellular parasites Chlamydia life cyle cell wall – diminished or no cell wall: no peptidoglycan in cell wall grow intracellularly elementary body – its “endospore-like” infective form reticulate body - intracellular replicative cellular form o Chlamydia trachomatis causes pelvic inflammatory disease and urethritis o Chlamydophila psittaci causes respiratory psittacosis (pneumonia) Question: The two domains of prokaryotes are… a. bacteria and archaea. b. bacteria and fungi. c. archaea and fungi. d. bacteria and protista. 15 Question: A spirochete's method of motility is the use of a(n)… a. external flagellum. b. axial filament. c. fimbriae. d. cilia. e. sheath. 16 Question: Elementary bodies are found in the phylum… a. Planctomycetes. b. Chloroflexi. c. Chlamydiae. d. Bacteroidetes. e. Spirochetes 17  Ch.11 – Prokaryotes o Classifying bacteria o Non-proteobacteria bacterioides, anoxygenic photosynthesizers, spirochetes, chlamydia o Proteobacteria anoxygenic / oxygenic photosynthesizers, enterobacteriaceae, pathogenic proteobacteria o Gram positive bacteria firmicutes and actinobacteria o Prokaryotic diversity  proteobacteria: also all gram negative oxygen tolerating most obligate aerobes or facultative anaerobes great diversity (>30% of all known bacteria) largest bacteria phyla diverse matabolisms - include heterotrophs, lithotrophes and photosynthesizers 5 classes: alpha, beta, gamma, delta, epsilon include oxygenic and anoxygenic photosynthetic bacteria o cyanobacteria - oxygenic o green sulfur / non-sulfur bacteria - anoxygenic many pathogenic species (Shigella; Salmonella) contain nitrogen fixing species  green sulfur/non-sulfur bacteria anoxygenic photosynthetic bacteria o carry out anoxygenic photosynthesis – using electron donor that IS NOT water o light + CO2 + H2S = C6H12O6 + 2S green sulfur bacteria uses H2S instead of H2O as electron donor for photosynthesis produce sulfides instead of oxygen green sulfur aerotolerant anaerobes bacteria absorb light at lower wavelengths than purple sulfur bacteria green non-sulfur bacteria uses organic H source other than H2S or H2O as electron donor aerotolerant anaerobes absorb lower wavelengths than purple non-sulfur bacteria *Notes* “green” and “purple” named for different wavelengths used with photosynthesis sulfur bacteria are obligate anaerobes or microaerophiles sulfur mineral springs - Yellowstone non-sulfur bacteria can tolerate aerobic environments  cyanobacteria aka “blue green” algae Gloeocapsa cyanobacteria unicellular nonfilamentous Merismopedia filamentous cyanobacteria with heterocysts forms quartets, octets, and so on cyanobacteria - the oxygenic photosynthetic bacteria Light + CO2 + H20 = C6H12O6 + O2 use water as electron donor and produce oxygen fixes most of carbon dioxide in ecosystem many contain heterocyst's that can fix nitrogen – fix much biosphere’s nitrogen many contain gas vesicles that provide buoyancy unicellular or filamentous; colonial  enterobacteriaceae o family of enteric (gut) Gram-negative rods o all are facultative anaerobes and motile o E. coli most numerous and common enterobacteriaceae o many rapid identification tests to help identify infection as enterobacteriaceae o if infection is enterobacteriaceae species – indicative of fecal contamination as source of infection! fecal coliform – gm neg. rod that ferments lactose with gas production o contain both symbiotic/commensual and pathogenic species almost all Escherichia coli strains – commensal E. coli O157:H7 – pathogen – shiga toxin! enteric rod Proteus mirabilis enteric rod E. coli enteric rod Salmonella enterica  Triple Sugar Iron (TSI) test sugar metabolism and hydrogen sulfide production diefferentiate eteric species: E. coli, Salmonella, Shigella, Proteus, and Pseudomonas Enterotube 13 rapid ID test of enteric bacteria ImVic test 4 tests to identify enterobacteriaceae indole, MR, VP, and citrate tests  pathogenic proteobacteria Yersinia pseudotuberculosis and Yersinia pestis o both enterobacteriaceae! o Y. pseudotuberculosis causes gastrointestinal disease that “mimic’s” an appendicitis transmitted from animals to humans by contaminated food or water o Y. pestis causes a deadly disease – the plague transmitted from animals to humans by infected flea.  pathogenic proteobacteria Pseudomonaceae Legionella pneumophila o obligate aerobic bacilli. o intracellular pathogen related to Pseudomonas. o although aerobic - some use alternative electron o grows inside protozoa and human macrophages acceptors - such as nitrate. o prevents lysosome fusion o widespread in soil as a decomposer - important in o transmitted by inhalation or aspiration of natural recycling and soil turnover contaminated aerosols – water jets, sprays or mist Pseudomonas aeruginosa commonly grows in soil as a decomposer but is opportunistic pathogen to humans can infect surgical wounds or form biofilms in the lungs of cystic fibrosis patients A. L. pneumophila cell - caught by an amoeba’s pseudopod. B. L. pneumophila cells - colonizing the amoeba.  pathogenic proteobacteria o A. Vibrio cholera - flagellated, comma-shaped bacterium attaching to villi in small intestine; causes cholera o B. Neisseria gonorrhoeae - diplococci with attachment pili; cause of gonorrhea. o C. Helicobacter pylori - enteric stomach bacteria: can cause gastritis / ulcers. additional pathogenic intracellular proteobacteria… o Rickettsia and Ehrlichia - Rocky Mountain spotted fever and Ehrlichiosis (rat-bite fever) o Coxiella (similar to Rickettsia) - Q fever – 1 of most infectious bacteria known (LD50 = 1) o Brucella - brucellosis (mediterranian fever). o Bdellovibrio - predatory, attack other bacterial host cells such as E. coli  Group Discussion: Prokaryotes 1. Provide and explain four differences between bacteria and archaea. 2. Distinguish proteobacteria from non-proteobacteria – provide examples of each. 3. Describe the unique cell traits of pathogenic spirochetes. 4. Describe and provide examples of the group enterobacteriaceae and indicate why they are significant.  Ch.11 – Prokaryotes o Classifying bacteria o Non-proteobacteria bacterioides, anoxygenic photosynthesizers, spirochetes, chlamydia o Proteobacteria anoxygenic / oxygenic photosynthesizers, enterobacteriaceae, pathogenic proteobacteria o Gram positive bacteria firmicutes and actinobacteria o Prokaryotic diversity  Gram - positive bacteria - two groups 1. Firmicutes 2. Actinobacteria o most recent group of bacteria evolutionarily; unique cell wall (gram+) o classified by “G-C ratio” or “GC content” o % of nitrogenous bases in DNA that are either Guanine or Cytosine A-T: 2 hydrogen bonds Firmicutes - “tough skin” low “G+C” (guanine and cytosine) content standard Gram positive cell wall several layers of peptidoglycan supported with teichoic acids Actinobacteria high “G+C” content G-C: 3 hydrogen bonds modified standard Gram positive cell wall peptidoglycan with additional thick waxy coat (mycolic acid)  1. Firmicutes - low “GC content” gram-positive bacteria endospore producing firmicutes: endospore: dormant state – can exist for millions of years resistant to drying, freezing, and chemical disinfectants Clostridium o endospore-producing rods o obligate anaerobes o include severely pathogenic species: C. tetani, C. botulinum, C. perfringens, and C. difficile Bacillus o endospore-producing rods o include pathogenic species B. anthracis - causes anthrax B. thuringiensis - an insect pathogen Clostridium difficile B. cereus - causes food poisoning watery diarrhea, fever, nausea, and abdominal pain  non-endospore firmicutes: Listeria spp. o intracellular pathogen; psychrotroph o causing diseases affecting GI tract and nervous system Lactic acid bacteria o intracellular pathogen that travels on tails of actin! Lactococcus and Lactobacillus ferment milk to make yogurt and cheese Listeria monocytogenes Lactococcus lactis A. Fluorescent antibody microscopy green - tails of polymerized actin (green) Lactobacillus red/yellow - Listeria cell bodies traveling behind the actin chain within infected macrophage. bulgaricus B. Invading bacteria polymerize host actin at cell pole form an actin tail. Actin tails propel them through host cytoplasm pushes out through cell membrane to invade neighboring cell  other important firmicutes: Staphylococcus o grapelike clusters Streptococcus o often antibiotic resistant o coccus in chains o S. aureus - causes wound skin infections o produces four toxin types o produce enzymes that destroy tissue hemolysin – lyse red blood cells o pathogenic streptococci include leukotoxin – lyse white blood cells S. pneumoniae – causes pneumonia enterotoxin – intestinal toxin S. mutans - causes dental caries toxic-shock syndrome toxin-1 - sepsis o beta-hemolytic streptococci - hemolyze blood S. pyogenes Species of Enterococcus, Streptococcus, and Staphylococcus distinguished by level of hemolysis on blood agar plates A - Streptococcus pneumoniae - alpha (moderate) hemolysis A and B – Staphylococcus; C and D - Streptococcus B - Staphylococcus aureus - beta (high) hemolysis  Firmicutes o low “GC Content” gram-positive bacteria  2. Actinobacteria o high “GC Content” gram-positive bacteria o broad group - includes antibiotic producers, decomposers, and pathogens o cell wall includes unusual cell wall lipids - such as mycolic acid o most stain with acid-fast stain. Corynebacterium Corynebacterium diphtheriae - causes diphtheria difficulty breathing, heart failure, paralysis Propionibacterium produces propionic acid Propionibacterium acnes - causes acne Gardnerella Gardnerella vaginalis - causes vaginitis Streptomyces largest genus of actinobacteria most produce endospores isolated from soil Streptomyces produce most antibiotics  Actinobacteria acid-fast bacteria Mycobacterium tuberculosis mycolic acid cell wall: intracellular pathogen highly infective obligate aerobe – infects lungs highly contagious – aerosol transmission many antibiotic resistant strains A. Acid-fast stain - M. tuberculosis. B. Crinkled appearance of M. tuberculosis colonies Mycobacterium leprae mycolic acid cell wall; intracellular pathogen causes leprosy - infects peripheral nerves targets skin, eyes, nose, and mouth, not highly contagious – direct contact Mycobacterium leprae leprosy infection  Actinobacteria o high “GC Content” gram-positive bacteria  Ch.11 – Prokaryotes o Classifying bacteria o Non-proteobacteria bacterioides, anoxygenic photosynthesizers, spirochetes, chlamydia o Proteobacteria anoxygenic / oxygenic photosynthesizers, enterobacteriaceae, pathogenic proteobacteria o Gram positive bacteria firmicutes and actinobacteria o Prokaryotic diversity  Archaea o “extreme bacteria” – all are anaerobic extremophiles pseudomurein cell wall - lacks peptidoglycan Halococcus salifodinae Staphylothermus marinus Yellowstone: thermal hot spring home to many archaea species Characteristics: unique cell wall – pseudomurein enable survival in extreme environments Extremophiles: heterotrophic – require organic/inorganic carbon for metabolism Extreme Halophiles - require salt concentration > 25% non pathogenic – no species has caused human disease Thermophiles - require growth temperature >80C environmental niche – extreme environments – including our gut Psychrophile – require low temperature