Microbial Nutrition and Colonies

Bacteria Morphology

Macronutrients -C, O, H, N, S P, K, Ca, Fe -needed in large amounts

Micronutrients Mn, Zn, Co, Mo, Ni, Cu Usually obtained through water

Nutritional Types of Microorganisms

1. Carbon: (Autotroph v. Heterotroph) Heterotroph: C from preformed organic molecules Autotroph: C from CO2

2. Energy Source (Phototroph v. chemotroph) Phototroph: light source Chemotroph: oxidize organic or inorganic molecules

3. Electron source (lithotrophs vs. organotrophs) Lithotrophs: inorganic sources Organotrophs: organic sources

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

Bacterial Taxonomy - uses rRNA nucleotide sequences for classification - Strain: group of organisms within a species with characteristics which render it distinctive

The Bacterial Tree - 50 well-studied Phyla Ex. -Thermophiles -cyanobacteria -Gram-positives -Spirochetes -chlamydiae -Many Bacteria yet to be classified

Cyanobacteria - many grow as filaments -type of "algae"

Gram-positive Firmicutes - rods and cocci -many are pathogens Ex. Staphylococcus, Streptococcus

Gram-positive Endospores - heat resistant for millenia Ex. Clostridium: Tetanus, botox, gangrene Bacillus: anthrax

Gram-positive actinobacteria - Acid-fast cell walls EX. Mycobacterium leprae, tuberculosis

Alpha Protetobacteria -Photoheterotrophs: -Endosymbionts: Ex. Rhizobium (root nodules) Rickettsias (rocky mountain spotted fever)

Enteric Gamma Proteobacteria -many form biofilms -pathogens Ex. Salmonella -Escherichia coli -Proteus -Shigella

Delta Proteobacteria "Social" bacteria -form aggregations of bacteria -some parasitize other bacteria

Epsilon Proteobacteria Heliobacter pylori: cause stomach ulcers -burrows under protective mucous layer -opportunistic pathogen

Bacteriodetes - major flora of human colon -break down toxins in food - provide nutrients

Chlamydiae - intracellular parasite -grows within host cells Transmission: Elementary Bodies: "spore" that is transferred to new host

Microbial Interactions with humans 1. Ectosymbiont: surface on another organism 2. Endosymbiont: located within another organism 3. Consortium: contact between dissimilar organisms

Microbiome - new field of study -dedicated to study of microbial diversity on humans

Gnotobiotic Animals - microbe-free animals - used to study complex relationships of microbes - highly susceptible to infection

Normal Microbiota of Human body - interactions vary commensalisms, mutualisms, parasitism -vary by body region

Skin Microbes - many -