4 Types of Diversity Morphological diversity: Structural diversity: Bacilli, cocci, and spirals are 3 common shapesFilamentous forms, pleiomorphic forms.There are many varieties of size, ranging from submicroscopic up to a few bacteria that can be seen with the naked eye.Structural diversity:Cell wallGram-positive and gram-negative bacteria.Absence of wallsExternal appendagesEndosporesMetabolic diversity:Heterotrophs vs autotrophs.Fermentation vs respiration.Aerobic and anaerobic.PhotosynthesisGenetic diversity:Small ribosomal subunit sequencing – 16S r RNA
5 Detailed phylogenetic tree of the major lineages (phyla) of Bacteria based on 16S ribosomal RNA sequence comparisons
8 Phylum Firmicutes Gram-positive Low G + C (less than 60%) Very popular is the plasmid exchange across species and genera of this phyla.Orders:
9 Phylum Firmicutes Rods: Genus Bacillus Genus Clostridium Aerobic and facultative anaerobicEndospore forming rodsCommon in soilHuman and animal disease – anthrax, food poisoningGenus ClostridiumObligate anaerobesToxin producedHuman pathogens – tetanus, botulism, gangrene, diarrheaGenus LactobacillusGenerally aerotolerant anaerobes, lack an electron-transport chainLactic acid fermentation of carbohydratesUsed for yogurt, buttermilk, pickles, sauerkrautLive on human mucous – oral cavity, vagina, intestineGenus ListeriaCan grow at 4°CContaminant of meat and dairySurvive phagocytosisCross placenta cause fetus damages
10 Phylum Firmicutes Coccus Genus Mycoplasma Genus Staphylococcus Coci in clustersTolerate high osmotic pressureLive on human skin and noseHuman disease – food poisoning, toxic shock syndromeGenus StreptococcusCoci in chainProduce tissue and cell digesting enzymes and toxinsAvoid phagocytosisHuman disease – pharyngitis, dental caries, scarlet fever, impetigo, rheumatic fever, neonatal sepsisGenus EnterococcusLive on human mucous - oral cavity, vagina, intestineAntibiotic resistantHuman disease – nosocomial infections, surgical wounds, urinary tract infectionsGenus MycoplasmaNo cell wall, sterols in membrane, pleomorphicµmCan grow in filamentous form or singleHuman disease - pneumonia M. pneumoniae
11 Phylum Actinobacteria Gram-positive - High G + C (more than 60%)Coccoid, rod-coccoid , fragmenting hyphal forms, filamentous with permanent and highly differentiated branched myceliumPhysiologically very diverseproduction of numerous extracellular enzymes, including antibiotics
12 Phylum Actinobacteria Genus Mycobacteriumusually bacilli, slow growthcell wall has mycolic acid (acid fast)human diseases: leprosy and tuberculosisGenus Propionibacteriumrod shape, form propionic acidon human skin, cause acne.Genus Cornebacteriumrods, pleomorphichuman disease: diphtheriaGenus Streptomycesaerobes, filamentous, common in soilproduce external asexual sporesproduce many antibioticsGenus Actinomycesfacultative anaerobes, filamentous,in human oral mucoushuman disease: actinomycosisGenus Nocardiaaerobes, filamentous, reproduce by fragmentationacid fast,in soilhuman disease: pulmonary infections, mycetoma
14 Phylum Proteobacteria Mythical Greek god, Proteus, who could assume many shapesProteobacteria is the largest group of bacteria.This phylum contains 2086 species or 32.3% of all known bacteria.Proteobacteria are all gram negative.All four of major nutrition types are presentPurple phototrophic.Nitrifying bacteriaEnteric bacteriaBacteria responsible for animal bioluminescence.Many pathogens.More morphologically unusual bacteria.Symbiotic genera.Phylum Proteobacteria
15 Class (alpha) Proteobacteria Obligate pathogenGenus RikettsiaInduce phagocytosis and multiplies in phagocytesTransmitted via flea and tick bitesHuman disease – spotted fever: typhus, Rocky Mountain – damage the permeability of blood capillaries.Genus EhrlichiaLives in white blood cells- phagocytesTransmitted via tick biteHuman disease ehrlichiosisHuman pathogensGenus BartonellaTransmitted via cat salivaHuman disease – cat-scratch diseaseGenus BrucellaSurvives phagocytosisHuman disease brucellosisPlant pathogensGenus, Bradyrhizobium, AgrobacteriumIndustrially importantGenus Acetobacter, GlaunobacterConvert ethanol to acetic acidNitrogen fixationGenus Rhizobium, AzospirilumGrow on roots
17 The (beta) Proteobacteria Genus Spirillumspiral, motile: polar flagellain fresh waterhuman disease: rat bite fevertransmitted via rodent bite or fecal contaminationGenus Burkholderiamotile: single polar flagellumDiverse carbon sourcegrow in disinfectantshuman disease: respiratory infectionsGenus Bordetellahuman pathogenwhooping cough/pertussisGenus Neisseriaon mucus membranes of mammalsGonorrhoea, meningitisGenus Zoogloeaaerobic sewage treatmentform precipitating flocs
18 Class (gamma) Proteobacteria Genus PseudomonasOpportunistic pathogensMetabolically diverseMotile -polar flagellaProduce water soluble blue pigmentCan live on soap, adhesives, antisepticsCan grow at 4°C: food spoilageAntibiotic resistantWound infections, infections in immunocompromized patientsGenus Vibrio:curved rod,Found in coastal waterVibrio cholerae causes choleraGenus LegionellaLive in fresh waterContaminant of AC ductsHuman disease – Legionnaire’s diseaseGenus Azotobacter and AzomonasNitrogen fixingFigure 11.7
19 Class (gamma) Proteobacteria Order Enterobacterialesfacultative anaerobes, ferment carbohydratesPeritrichous flagella,Have fimbriae and Sex piliProduce bacteriocinsHuman pathogens, most cause gastrointestinal, urinary or respiratory tract infectionsEscherichiaNormal microbiota, can cause gastroenteritis, UTIsSalmonellaCommon animal microbiotaToxin cause salmonellosisShigellaToxin cause shigellosisEnterobacterIn soil, water, animals and humans, can cause nosocomial and UTIsKlebsiellaIn soil and water, can fix nitrogen, can cause pneumoniaProteusSwarming growth, wound infectionsSerratiaRed pigment , can cause respiratory and UTIsYersiniaBlack Death plaque, transmitted via fleas from rats and ground squirrelsErwiniaPlant pathogen – hydrolyze pectin: plant rot
20 Class (delta) Proteobacteria Include some bacteria that have predators on other bacteriaImportant contribution to sulfur cycle.Genus Bdellovibriomotile: single polar flagellaattacks other Gram negative bacteriareproduces in periplasmGenus Myxococcusmotile via slime trailsdigest bacterialow nutrients: aggregate to form a fruiting body ! myxospores
21 Class (epsilon) Proteobacteria Slender gram-negative rods that are curved to spirilloidFlagella – one polar flagellum or multiple flagellaPathogens - peptic ulcers, stomach - flagellatedUnicellular to multicultural filamentous and colonial typeGenus Campylobacteranimal disease: spontaneous abortionhuman disease: food borne intestinal diseaseGenus Helicobacterhuman disease: peptic ulcers
22 Purple and Green Photosynthetic Bacteria Oxygenic and Anoxygenic photosynthesislight2H2O + CO2(CH2O) + H2O + O2light2H2S + CO2(CH2O) + H2O + 2S
23 Phylum CyanobacteriaThe only bacteria that carry out oxygenic photosynthesisSome growth in associations with plants and animalsCO2 fixation, Fix nitrogenGliding motilityThe chloroplasts found in all photosynthesized organisms evolved from this group of bacteria
24 Phylum Spirochetes Coiled morphology Axial filament-enclosed in the space between the outer sheath and the body of the cellNumber of important pathogenic bacteriaTreponema – syphilisBorrelia – lyme disease, transmitted via tick from miceLeptospira – leptospirosis, transmitted via animal urine contaminated water
25 Phylum Chlamydiae No peptidoglycan Divide in animal cell Produce spore-like elementary bodiesC. trachomatisTrachomaUrethritisPelvic inflammatory diseaseC. pneumoniaePneumoniaC. psittaciCauses psittacosisFigure 11.23
26 Bacteroidetes and Fusobacteria Phylum BacteroidetesAnaerobicIn mouth and large intestineCellulose-degrading in soilGenus BacteroidesIn human and animal GIT, can infect puncture wound and peritoneumGenus CytophagaIn soil, degrade cellulosePhylum FusobacteriaFusobacteriumFound in mouthMay be involved in dental diseases
27 Domain Archaea Cell wall - No peptidoglycan Unusual metabolism that allow them to live in the most inhospitable places on Earth (extreme environments)Oxygen-free habitatsBoiling sulfuric acid pools near volcanoesSulfur hot springsGlacial iceMethane seepsDesert sandsAcid minesOil leaksPolluted watersToxic waste dumps
28 Detailed phylogenetic tree of the Archaea based on 16S ribosomal RNA sequence comparisons.
29 Domain Archaea Korarchaeota; Crenarchaeota: Euryarchaeota: Found only in high temperature hydrothermal environments (hot springs).None have been grown in pure culture.Crenarchaeota:They use sulfur compounds as electron donors or as acceptors.Most thermophilic organisms known.Significant in deep-sea environment and as wall as in polar seasEuryarchaeota:Methanogens - microorganisms that produce methane as a metabolic byproduct in anoxic conditionsHalophiles - extremophile organisms that live in environments with very high concentrations of salt. ("salt-loving“).ThermophilesNanoarhaeotarecently discovered smallest organism, nanosized, hyperthermophilic symbiont.
30 Microbial Diversity Bacteria size range Thiomargarita (750 µm) Nanoarhaeota (0.4 µm)PCR indicates up to 10,000 bacteria/g of soil.Many bacteria have not been identified or characterized because they haven't been culturedNeed to be cultured to understand their metabolism and ecological roleNeed special nutrientsAre part of complex food chains requiring the products of other bacteriaFigure 11.26
31 Learning objectives Distinguish among the alpha proteobacteria . Distinguish among the beta proteobacteria.Distinguish among the orders of gamma proteobacteria .Distinguish among the delta proteobacteria.Distinguish among the epsilon proteobacteria.Compare and contrast the green and purple photosynthetic bacteria with the cyanobacteria.Distinguish among the low G + C gram-positive bacteria.Distinguish among the high G + C gram-positive bacteria.Distinguish among the gram-negative nonproteobacteria.Distinguish, spirochetes, Bacteroidetes, and Fusobacteria.