Microbiology - Week 6 - Lecture 1 - Bacterial Taxonomics (1) (1).pdf

BACTERIAL TAXONOMICS GROUPING BACTERIA Prepared by: Nick Inglis, Ph.D. BMS 100 Week 6 Use CO2 for carbon, light for E Use light for energy, Must consume organic compounds for carbon 4 GROUPS OF MICROORGANISMS Use inorganic energy sources like Hydrgoen Sulfide, Ammonia, etc; Get carbon from CO2 Consu...

BACTERIAL TAXONOMICS GROUPING BACTERIA Prepared by: Nick Inglis, Ph.D. BMS 100 Week 6 Use CO2 for carbon, light for E Use light for energy, Must consume organic compounds for carbon 4 GROUPS OF MICROORGANISMS Use inorganic energy sources like Hydrgoen Sulfide, Ammonia, etc; Get carbon from CO2 Consume organic material for carbon Get energy from breaking down organic material THE 3 DOMAINS OF LIFE SIMPLE PHYLOGENETICS: HOW DO WE ACTUALLY MAKE THESE TREES? rRNA sequence in land plants A U A U C G A G rRNA sequence in green algae A U A U G G A G rRNA sequence in mammals A U A U G C U G PHYLUM CHLOROFLEXI (green nonsulfur) BACTERIA Thermophilic bacteria PHYLUM DEINOCOCCUS-THERMUS Deeply branching bacteria GRAM-NEGATIVE BACTERIA PHYLUM PROTEOBACTERIA Rhodospirilla () (purple nonsulfur) Rickettsias () PHYLUM AQUIFICAE Nitrifying () Rhizobium () Myzobacteria () PHYLUM CHLOROBI (green sulfur) Campylobacteria () Pseudomonads () Neisserias () PHYLUM CYANOBACTERIA PHYLUM FIBROBACTERES PHYLUM CHLAMYDIAE PHYLUM SPIROCHAETES PHYLUM PLANCTOMYCETES PHYLUM KORARCHAEOTA PHYLUM BACTEROIDETES ARCHAEA PHYLUM EURYARCHAEOTA Methanogens PHYLUM FIRMICUTES PHYLUM FUSOBACTERIA PHYLUM CRENARCHAEOTA Clostridia Halophiles Mycoplasmas Bacilli-Lactobacilli Streptomyces Arthrobacter Atopobium Corynebacterium Mycobacterium Nocardia PHYLUM ACTINOBACTERIA GRAM-POSITIVE BACTERIA High G+C Gram-positive Thermophilic archaea DEEPLY BRANCHING BACTERIA rRNA sequences and characteristics indicate these guys branched off early in the tree of life. E.g., all are autotrophic – why is this significant? E.g.2 – many live in hot acidic anaerobic environments and can withstand large degrees of UV radiation – why is this significant? REPRESENTATIVES OF DEEPLY BRANCHING BACTERIA: Aquifex 83°C Deinococcus PHOTOTROPHIC BACTERIA Acquire energy by converting light energy into chemical energy through pigment molecules Pigments embedded in thylakoids PIGMENT MOLECULES ABSORB LIGHT OF SPECIFIC WAVELENGTHS… The colour of the bacteria will be determined by the wavelengths not absorbed Beam of light (let’s just say white light) White light is actually the combination of the entire visible spectra (so many different wavelengths) Hypothetical pigment molecule A -absorbs all but red wavelengths PIGMENT MOLECULES ABSORB LIGHT OF SPECIFIC WAVELENGTHS… Beam of light (let’s just say white light) White light is actually the combination of the entire visible spectra (so many different wavelengths) All other wavelengths are absorbed – i.e. That pigment molecule has picked up the energy of all of those wavelengths PIGMENT MOLECULES ABSORB LIGHT OF SPECIFIC WAVELENGTHS… The pigment molecule will be red, because that is what it’s reflecting! PHOTOTROPHIC BACTERIA: 1. CYANOBACTERIA (FORMERLY B-G ALGAE) Anabaena 12 H2O + 6 CO2+ Photons C6H12O6 + 6 H2O + 6 O2 **Just like plants and algae! Nitrogen fixation Merismopedia Oscillatoria PHOTOTROPHIC BACTERIA: 2. GREEN AND PURPLE PHOTOTROPHS 12 H2S + 6 CO2+ Photons C6H12O6 + 6 H2O + 6 S **No oxygen produced - Anoxygenic Internal sulfur deposits Some green phototrophs do not use sulfur Purple phototrophs T WO T Y P ES O F G R A M - P O S I T I V E BAC T E R I A : LOW G + C G R A M P O S I T I V ES A N D H I G H G + C G R A M P O S I T I V ES All depends on G-C content of DNA on chromosomes < 50% G-C – low G+C; > 50% - high GC Peptidoglycan layer (cell wall) Cytoplasmic membrane Gram-positive cell wall LOW G+C GRAM POSITIVE BACTERIA (PHYLUM FIRMICUTES): 1. CLOSTRIDIA Rod shaped (bacilli), obligate anaerobes Frequently form endospores Famous members: C. tetani (tetanus); C. perfringens (gangrene); C. botulinum (botulism); C. difficile (severe diarrhea) LOW G+C GRAM POSITIVE BACTERIA (PHYLUM FIRMICUTES): 2. MYCOPLASMAS Lacking cell wall – DNA sequencing still groups them with the gram-positives E.g., Mycoplasma pneumoniae Distinctive colonies on agar plates LOW G+C GRAM POSITIVE BACTERIA (PHYLUM FIRMICUTES): 3. OTHER GROUPS Bacillus – endospore forming; peritrichous flagella; common in soil Bt toxin Bacillus thuringiensis Famous member: B. anthracis LOW G+C GRAM POSITIVE BACTERIA (PHYLUM FIRMICUTES): 3. OTHER GROUPS Listeria – rod shapped; no endospores Famous member: L. monocytogenes (Can invade white blood cells!) LOW G+C GRAM POSITIVE BACTERIA (PHYLUM FIRMICUTES): 3. OTHER GROUPS Lactobacillus – rod-shaped; no spores, naturally occuring in stomach mouth, intestinal tract, vagina Microbial antagonists – protect body from growth of pathogens HIGH G+C GRAM POSITIVE BACTERIA (PHYLUM ACTINOBACTERIA): 1. CORYNEBACTERIUM Rod shaped or pleomorphic (famous species: C. diptheriae) Reproduce by snapping division (seen as V-shapes or pallisades) HIGH G+C GRAM POSITIVE BACTERIA (PHYLUM ACTINOBACTERIA): 2. MYCOBACTERIUM Exclusively aerobic species; slightly curved straight rods Take months to grow on plates! Famous members: M. leprae and M. tuberculosis GRAM STAIN FAILS TO IDENTIFY MYCOBACTERIUM AND NOCARDIA BACTERIA Gram positive; they have very waxy cell walls that reject crystal violet The Ziehl-Neelsen acid-fast staining technique used instead Acid-fast bacteria – pink/red Non-acid-fast - blue HIGH G+C GRAM POSITIVE BACTERIA (PHYLUM ACTINOBACTERIA): 3. ACTINOMYCETES Form branching filaments (look like fungi!) Reproduce by spores at ends of filmanets 3 sub groups: Actinomyces, Nocardia, Streptomyces GRAM-NEGATIVES: PHYLUM PROTEOBACTERIA: 1. ALPHAPROTEOBACTERIA Aerobes that can survive with little nutrients Possess prostheca Prostheca GRAM-NEGATIVES: PHYLUM PROTEOBACTERIA: 1. ALPHAPROTEOBACTERIA Famous member: Rhizobium, a Nitrogen fixer Root nodule Rock or other substrate Prostheca Flagellum GRAM-NEGATIVES: PHYLUM PROTEOBACTERIA: 1. ALPHAPROTEOBACTERIA Swarmer cell Cell doubles in size or Another example: Caulobacter Rosette OTHER GRAM -VES Beta-proteobacteria: Neisseria (Gonorrhea), Bordetella (Pertussis) Gamma-proteobacteria: Pseudomonas, Legionella (Legionnaire’s Disease, Pontiac Fever CHLAMYDIA LIFE CYCLE OTHER GRAM-NEGATIVES: Spirochetes – flexible, spiral shaped bacteria; corkscrew motility E.g., Trepnnema (Syphillis) and Borrelia (Lyme Disease) THANK YOU! A N D H AV E A L O V E LY D AY !