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Prokaryotes, Eukaryotes, and Non-living Infectious Particles. Introduction to Microbiology Common Pathogens. The Prokaryotes. Proteobacteria. All Gram-negative Many pathogens. Also organisms that do nitrogen fixation Most use flagella for movement; some non-motile or use gliding motility
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Prokaryotes, Eukaryotes, and Non-living Infectious Particles Introduction to Microbiology Common Pathogens
Proteobacteria • All Gram-negative • Many pathogens. Also organisms that do nitrogen fixation • Most use flagella for movement; some non-motile or use gliding motility • Alpha, Beta, Gamma, Delta and Epsilon
Betaproteobacteria • Aerobic or facultative bacteria that are often highly versatile in their degradation capacities • Contains mostly human pathogens • Example: Neisseria species.
The Betaproteobacteria • Bordetella • Chemoheterotrophic; rods • B. pertussis • Burkholderia • Nosocomial infections Figure 24.7
Gammaproteobateria • Class of several medically, ecologically and scientifically important groups of bacteria • Includes Pseudomonas aeruginosa, Vibrio species (Cholera), E. coli, Salmonella species, Shigella species, etc.
The Gammaproteobacteria • Pseudomonadales • Pseudomonas • Opportunistic pathogens • Metabolically diverse • Polar flagella Figure 11.7
The Gammaproteobacteria • Vibrionales • Found in coastal water • Vibrio cholerae causes cholera • V. parahaemolyticus causes gastroenteritis Figure 11.8
Enterobacter Erwinia Escherichia Klebsiella Proteus Salmonella Serratia Shigella Yersinia The Gammaproteobacteria • Enterobacteriales (enterics) • Peritrichous flagella; facultatively anaerobic
More Gammaproteobacteria Figure 11.9b
Yersinia enterocoliticaCauses Yersinosis; enterocolitis. Zoonotic disease.
The Epsilonproteobacteria • Helicobacter • Multiple flagella • Peptic ulcers • Stomach cancer Figure 11.12
Epsilonproteobacteria • Mainly the curved/spirilla • Most of the known species inhabit the digestive tract of animals and serve as symbionts or pathogens( • Helicobacter spp. in the stomach • Campylobacter spp. in the duodenum.
Epsilonproteobacteria • Campylobacter jejuni – causes food borne intestinal illness.
Gram-Positive Bacteria - Firmicutes • Low G + C • Gram-positive
ClostridialesGram positive; spore producers; obilgate anaerobes • Clostridium Figure 11.15
Bacillales Gram positive; aerobic of facultative anaerobes; Bacillus, Listeria and Staphylococcus • Staphylococcus • Cocci Figure 11.18
Lactobacillales • Generally aerotolerant anaerobes; lack an electron-transport chain • Lactobacillus • Streptococcus • Enterococcus • Listeria [Insert Figure 11.19] Figure 11.19
Actinobacteria • High G + C • Gram-positive
Actinobacteria • Actinomyces • Corynebacterium • Frankia • Gardnerella • Mycobacterium • Nocardia • Propionibacterium • Streptomyces
Chlamydiasobligate intacelluar parasites; unique life cycles • Chlamydia trachomatis • Trachoma • STI, urethritis • Chlamydophila pneumoniae • Chlamydophila psittaci • Psittacosis Figure 11.24b
Life Cycle of the Chlamydias Figure 11.24a
SpirochetesAll posses axial filaments • Borrelia • Leptospira • Treponema Figure 11.25
Bacteroidetes • Gram negative, non-sporeforming, anaerobic, and rod-shaped bacteria that are widely distributed in the environment, including in soil, in sediments, sea water and in the guts and on the skin of animals. • Bacteroides are found in the mouth and large intestine • Cytophaga: Cellulose-degrading in soil
Fusobacteria • Fusobacterium is a Gram-negative non-sporeforming bacterium that is widely known and studied as a human and animal pathogen. • Fusobacterium's exceptional ability to adhere with both Gram-negative and Gram-positive plaque microorganisms in biofilms (specifically in soft tissue) has made it a highly invasive pathogen. • Primarily given attention for its peridontal implications • Strains of Fusobacterium have been identified as pathogen to many parts of the body Figure 11.26
Domain Archaea Extremophiles • Hyperthermophiles • Pyrodictium • Sulfolobus • Methanogens • Methanobacterium • Extreme halophiles • Halobacterium
Microbial Diversity • PCR indicates up to 10,000 bacteria per gram of soil. • Many bacteria have not been identified because they • Haven't been cultured • Need special nutrients • Are a part of complex food chains requiring the products of other bacteria • Need to be cultured to understand their metabolism and ecological role
Fungi Mycology is the study of fungi
Molds • The fungal thallus consists of hyphae; a mass of hyphae is a mycelium. Figure 12.2
Yeasts • Unicellular fungi • Fission yeasts divide symmetrically • Budding yeasts divide asymmetrically Figure 12.3
Fungal Dimorphism • Pathogenic dimorphic fungi are yeastlike at 37°C and moldlike at 25°C Figure 12.4
Medically Important Phyla of Fungi • Zygomycota – saprophtyic molds (bread mold); mucor • Ascomycota – sac fungi; Candida albicans and Aspergillus flavus • Anamorphs – produce asexual spores only; ringworm (tinea) and dermatophytes • Basidiomycota – club fungi • Teleomorphic fungi – produce sexual and asexual spores • Cryptococcus (yeast-like state causes disease)
Dinoflagellates • Cellulose in plasma membrane • Unicellular • Chlorophyll a and c, carotene, xanthins • Store starch • Some are symbionts in marine animals • Neurotoxins cause paralytic shellfish poisoning Figure 12.13
Oomycota • Decomposers and plant parasites • Phytophthora infestans responsible for Irish potato blight • P. cinnamoni infects Eucalyptus • P. ramorum causes sudden oak death Figure 12.14
Medically Important Phyla of Protozoa • Archaezoa • Microspora • Amoebozoa • Apicomplexa • Ciliophora • Euglenozoa
Archaezoa • No mitochondria • Multiple flagella • Giardia lamblia • Trichomonas vaginalis (no cyst stage) Figure 12.16b