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Microbial Nutrition and Colonies
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Bacteria Morphology
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Macronutrients -C, O, H, N, S P, K, Ca, Fe -needed in large amounts
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Micronutrients Mn, Zn, Co, Mo, Ni, Cu Usually obtained through water
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Nutritional Types of Microorganisms
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1. Carbon: (Autotroph v. Heterotroph)
Heterotroph: C from preformed organic molecules Autotroph: C from CO2
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2. Energy Source (Phototroph v. chemotroph)
Phototroph: light source Chemotroph: oxidize organic or inorganic molecules
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3. Electron source (lithotrophs vs. organotrophs)
Lithotrophs: inorganic sources Organotrophs: organic sources
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Culture Media - must contain all nutrients required for growth -contains agar: used to solidify liquid media Functional Types: 1. Supportive/general 2. Enriched 3. Selective media 4. Differential
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Bacterial Taxonomy - uses rRNA nucleotide sequences for classification - Strain: group of organisms within a species with characteristics which render it distinctive
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The Bacterial Tree - 50 well-studied Phyla Ex. -Thermophiles -cyanobacteria -Gram-positives -Spirochetes -chlamydiae -Many Bacteria yet to be classified
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Cyanobacteria - many grow as filaments -type of "algae"
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Gram-positive Firmicutes
- rods and cocci -many are pathogens Ex. Staphylococcus, Streptococcus
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Gram-positive Endospores
- heat resistant for millenia Ex. Clostridium: Tetanus, botox, gangrene Bacillus: anthrax
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Gram-positive actinobacteria
- Acid-fast cell walls EX. Mycobacterium leprae, tuberculosis
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Alpha Protetobacteria
-Photoheterotrophs: -Endosymbionts: Ex. Rhizobium (root nodules) Rickettsias (rocky mountain spotted fever)
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Enteric Gamma Proteobacteria
-many form biofilms -pathogens Ex. Salmonella -Escherichia coli -Proteus -Shigella
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Delta Proteobacteria "Social" bacteria -form aggregations of bacteria -some parasitize other bacteria
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Epsilon Proteobacteria
Heliobacter pylori: cause stomach ulcers -burrows under protective mucous layer -opportunistic pathogen
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Bacteriodetes - major flora of human colon -break down toxins in food - provide nutrients
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Chlamydiae - intracellular parasite -grows within host cells Transmission: Elementary Bodies: "spore" that is transferred to new host
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Microbial Interactions with humans
1. Ectosymbiont: surface on another organism 2. Endosymbiont: located within another organism 3. Consortium: contact between dissimilar organisms
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Microbiome - new field of study -dedicated to study of microbial diversity on humans
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Gnotobiotic Animals - microbe-free animals - used to study complex relationships of microbes - highly susceptible to infection
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Normal Microbiota of Human body
- interactions vary commensalisms, mutualisms, parasitism -vary by body region
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Skin Microbes - many -
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