The Prokaryotes: Domains Bacteria and Archaea

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1 11/15/2016 PowerPoint Lecture Presentations prepared by Bradley W. Christian, McLennan Community College CHAPTER 11 The Prokaryotes: Domains Bacteria and Archaea 1

2 Tässä luvussa käsitellään laajasti eri bakteerisukuja ja lajeja. Tämän kurssin puitteissa riittää, että keskitytte: Gram neg., proteobakteerit Alphaproteobacteria Agrobacterium, Rhizobium Gammaproteobacteria Pseudomonales (Pseudomonas), Vibrionales (Vibrio cholerae) Salmonella E. coli Yersinia Epsilonproteobacteria Helicobacter Gram pos. bakteerit Clostridium, Bacillus, Lactobacillus, Staphylococcus Gram neg., ei proteobakteerit Pääsääntöisesti yhteyttäviä bakteereja, yleiskäsitys riittää 2

3 Table 11.1 Classification of Selected Prokaryotes* Proteobacteria From the mythological Greek god Proteus, who could assume many shapes Gram-negative Largest taxonomic group of bacteria Five classes 3

4 The Alphaproteobacteria Most are capable of growing with very low levels of nutrients The Alphaproteobacteria Rhizobium and Bradyrhizobium Fix nitrogen in the roots of leguminous plants (hernekasvi) Known by the common name of rhizobia (ilmakehän typpeä sitovat, typpi ammoniakkina kasveille) Agrobacterium Plant pathogen; causes crown gall Inserts a plasmid into plant cells, inducing a tumor Ti (tumor inducing) plasmid, important in plant gene technology (cloning vector) 4

5 Figure 9.19 Crown gall disease on a rose plant. Crown gall The Gammaproteobacteria Legionellales Legionella Found in streams, warm-water pipes, and cooling towers Causes legionellosis (Legioonalaistauti eli legionelloosi: kuumetauti, johon yleensä liittyy keuhkokuume) Coxiella C. burnetii: causes Q fever; transmitted via aerosols or milk 5

6 The Gammaproteobacteria Vibrionales Found in aquatic habitats V. cholerae causes cholera (oireiltaan vaihteleva) V. parahaemolyticus causes gastroenteritis (mahasuolitulehdus) Figure 11.8 Vibrio cholerae. 6

7 The Gammaproteobacteria Enterobacteriales Commonly called enterics inhabit the intestinal tract; ferment carbohydrates Facultative anaerobes Peritrichous flagella The Gammaproteobacteria Enterobacteriales (cont'd) Escherichia E. coli: indicator of fecal contamination; causes foodborne disease and urinary tract infections 7

8 E. coli Mikrobiologiassa eniten tutkittu bakteeri Suolistossa, syntetisoi K-vitamiinia Jotkut kannat patogeeneja, mm. pelätty ripulitaudin aiheuttaja Ehec Ehec = enterohemorraagiset E. coli kannat Nautojen ym. suolisto -> esim. huonosti kypsennetty jauheliha, pastöroimaton maito, kanat ja kananmunat? Vain bakteeria tarvitaan aiheuttamaan infektio! Salmonella 2400 serovars (?) Common form of foodborne illness Salmonella typhi causes typhoid fever (lavantauti, vakava suolistoinfektio) Ihmiseen kontaminoidun lihan, kanan, kananmunien, veden välityksellä Inkubaatioaika 8-48h tartunnasta -> bakteerit valtaavat limakalvon soluja -> valtava nesteiden menetys 8

9 Serovar A group of microorganisms characterized by a specific set of antigens Suomeksi: Serotyyppi on mikrobiologisessa ja virologisessa luokittelussa alalajin jälkeen seuraava pienempi yksikkö. Sitä käytetään bakteerien ja virusten eri kantojen luokittelussa pintarakenteessa olevien antigeenien avulla. The Gammaproteobacteria Enterobacteriales (cont'd) Yersinia Y. pestis causes plague (rutto) Transmitted via fleas (kirput) 9

10 The Epsilonproteobacteria Helical or curved; microaerophilic Campylobacter One polar flagellum C. jejuni causes foodborne intestinal disease Helicobacter Multiple flagella Cause peptic ulcers (vatsahaava), gastritis (mahatulehdus, vatsakatarri) and stomach cancer Figure Helicobacter pylori. Flagella 10

11 The Nobel Prize in Physiology or Medicine for 2005 jointly to Barry J. Marshall and J. Robin Warren for their discovery of "the bacterium Helicobacter pylori and its role in gastritis and peptic ulcer disease" 11

12 Cyanobacteria (The Oxygenic Photosynthetic Bacteria) Carry out oxygenic photosynthesis Many contain heterocysts that can fix nitrogen Gas vesicles that provide buoyancy Unicellular or filamentous Figure Cyanobacteria. Heterocysts Glycocalyx Filamentous cyanobacterium showing heterocysts, in which nitrogen-fixing activity is located A unicellular, nonfilamentous cyanobacterium, Gloeocapsa. Groups of these cells, which divide by binary fission, are held together by the surrounding glycocalyx. 12

13 Table 11.2 Selected Characteristics of Photosynthesizing Bacteria Chlamydiae No peptidoglycan in the cell wall; grow intracellularly Chlamydia and Chlamydophila Form an elementary body that is infective Chlamydia trachomatis causes trachoma and urethritis Chlamydophila psittaci causes respiratory psittacosis 13

14 Figure 11.15a Chlamydias. The elementary bodies are released from the host cell. Elementary body The bacterium's infectious form, the elementary body, attaches to a host cell. The reticulate bodies begin to convert back to elementary bodies. Host cell Nucleus The host cell phagocytizes the elementary body, housing it in a vacuole. Vacuole forming Vacuole Reticulate body The reticulate body divides successively, producing multiple reticulate bodies. The elementary body reorganizes to form a reticulate body. Life cycle of the chlamydias, which takes about 48 hours to complete Figure 11.15b Chlamydias. Elementary body Micrograph of Chlamydophila psittaci in the cytoplasm of a host cell. The elementary bodies are the infectious stage; they are dense, dark, and relatively small. Reticulate bodies, the form in which chlamydias reproduce within the host cell, are larger with a speckled appearance. Intermediate bodies, a stage between the two, have a dark center. Reticulate body Intermediate body 14

15 The Gram-Positive Bacteria Firmicutes (low G + C ratios) Actinobacteria (high G + C ratios) Firmicutes (Low G + C Gram-Positive Bacteria) Clostridiales Clostridium Endospore-producing Obligate anaerobes Includes disease-causing C. tetani (jäykkäkouristus), C. botulinum,c. perfringens,and C. difficile Endospore 15

16 Firmicutes (Low G + C Gram-Positive Bacteria) Bacillales Bacillus Endospore-producing rods B. anthracis causes anthrax (pernarutto) B. thuringiensis is an insect pathogen B. cereus causes food poisoning Staphylococcus Suuri osa ihmisen ja eläinten normaaliflooraa, mutta myös opportunistisia patogeeneja Grapelike clusters (viinirypäle!) S. aureus causes wound infections, is often antibiotic resistant, and produces an enterotoxin 50% of the population are carriers (nose, hands) / 50% väestöstä kantajia (nenä, kädet) Figure Bacillus. Endospore Collapsed B. thuringiensis Toxic crystal Bacillus thuringiensis. The diamond-shaped crystals shown next to the endospore are toxic to insects that ingest them. This electron micrograph was made using the technique of shadow casting. 16

17 Figure Staphylococcus aureus. Firmicutes (Low G + C Gram-Positive Bacteria) Lactobacillales Aerotolerant anaerobes; produce lactic acid from simple carbohydrates Lactobacillus colonize the body and are used commercially in food production 17

18 Firmicutes (Low G + C Gram-Positive Bacteria) Lactobacillales (cont'd) Streptococcus Spherical in chains (pallot ketjuissa) Produce enzymes that destroy tissue Beta-hemolytic streptococci hemolyze blood agar; includes S. pyogenes Non-beta-hemolytic streptococci include S. pneumoniae and S. mutans, which causes dental caries Figure Streptococcus. 18

19 Actinobacteria (High G + C Gram-Positive Bacteria) Often common inhabitants of soil Mycobacterium Outermost layer of mycolic acids that is waxy and waterresistant Often slow-growing M. tuberculosis causes tuberculosis M. leprae causes leprosy Actinobacteria (High G + C Gram-Positive Bacteria) Streptomyces Isolated from soil; produce most antibiotics Actinomyces Form filaments in the mouth and throat; destroy tissue Nocardia Form fragmenting filaments; acid-fast N. asteroides causes pulmonary infections 19

20 Archaea Arkeonit eli arkkieliöt Diversity Within the Archaea Learning Objective Name a habitat for each group of archaea. 20

21 Diversity Within the Archaea Distinct taxonomic grouping; lack peptidoglycan Extremophiles Halophiles Require salt concentration >25% Thermophiles Require growth temperature >80 C Methanogens Anaerobic and produce methane Figure Archaea. 21