Chapter 11Chapter 11

The Prokaryotes:The Prokaryotes:Domains Bacteria and ArchaeaDomains Bacteria and Archaea

Classification of Classification of ProkaryotesProkaryotes

Figure 10.6

Domain BacteriaDomain Bacteria Phylum ProteobacteriaPhylum Proteobacteria

Mythical Greek god, Proteus, who could Mythical Greek god, Proteus, who could assume many shapesassume many shapes

Are Gram-negativeAre Gram-negative 4 sub groups4 sub groups

The The (alpha) Proteobacteria (alpha) Proteobacteria The The (beta) Proteobacteria (beta) Proteobacteria The The (gamma) Proteobacteria (gamma) Proteobacteria The The (delta) Proteobacteria (delta) Proteobacteria The The (epsilon) Proteobacteria (epsilon) Proteobacteria

The The (alpha) (alpha) ProteobacteriaProteobacteria

Proteobacteria Proteobacteria include most include most proteobacteria proteobacteria capable of growth capable of growth at very low nutrient at very low nutrient levelslevels

Some have unusual Some have unusual morphologymorphology

Includes Includes agriculturally agriculturally important bacteriaimportant bacteria

Dichotomous key

The The (beta) Proteobacteria (beta) Proteobacteria

Usually found in Usually found in sewage and sewage and decomposition decomposition areasareas

Contains Contains Neisseria Neisseria gonorrhoeae gonorrhoeae which causes which causes gonorrhea and gonorrhea and Neisseria Neisseria meningitidismeningitidis cause of cause of meningitismeningitis

The The (gamma) (gamma) ProteobacteriaProteobacteria

Largest Largest proteobacteria proteobacteria subgroupsubgroup

Contains the Contains the Pseudomonas Pseudomonas which arewhich are Opportunistic Opportunistic

pathogenspathogens Metabolically Metabolically

diversediverse

Contains Contains EnterobacterialEnterobacterialeses

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The The (gamma) Proteobacteria (gamma) Proteobacteria Enterobacteriales (enterics); inhabit Enterobacteriales (enterics); inhabit

intestinal tracts of humans and other intestinal tracts of humans and other animalsanimals Gram negative, facultative anaerobicGram negative, facultative anaerobic

EnterobacterEnterobacter Escherichia**, Escherichia**, e.g e.g E. coliE. coli KlebsiellaKlebsiella ProteusProteus Salmonella**Salmonella** SerratiaSerratia ShigellaShigella

The The (gamma) (gamma) ProteobacteriaProteobacteria

The The (delta) Proteobacteria (delta) Proteobacteria

They include They include bacteria that bacteria that attack other attack other bacteriabacteria

Also include Also include Sulfur Sulfur reducing reducing bacteriabacteria

The The (epsilon) (epsilon) ProteobacteriaProteobacteria

Slender and Slender and helicalhelical

HelicobacterHelicobacter causes peptic causes peptic ulcersulcers

Classification of Classification of ProkaryotesProkaryotes

Figure 10.6

The Nonproteobacteria The Nonproteobacteria Gram-Negative BacteriaGram-Negative Bacteria

Gram-positive and Low G + C ratioGram-positive and Low G + C ratio DNA is made up of base pairs DNA is made up of base pairs Guanine (G) + Cytosine (C)Guanine (G) + Cytosine (C) Adenine (A) + Thymine (T)Adenine (A) + Thymine (T)

Includes important endospore forming Includes important endospore forming bacteriabacteria

FirmicutesFirmicutes

Includes Bacillus anthracis and Staphylococci

Includes Streptococcus

ActinobacteriaActinobacteria Gram-positive and High G + C ratioGram-positive and High G + C ratio Take on many shapes/forms Take on many shapes/forms

(pleomorphic)(pleomorphic)

Causes TB and leprosy

Domain ArchaeaDomain Archaea

Lack PeptidoglycanLack Peptidoglycan Many different Many different

morphologiesmorphologies Occur in extreme Occur in extreme

environmentsenvironments HyperthermophilesHyperthermophiles MethanogensMethanogens Extreme halophilesExtreme halophiles

PCR indicates up to 10,000 bacteria/gm of PCR indicates up to 10,000 bacteria/gm of soil. Many bacteria have not been identified soil. Many bacteria have not been identified or characterized because they:or characterized because they: Haven't been culturedHaven't been cultured Need special nutrientsNeed special nutrients Are part of complex food chains requiring the Are part of complex food chains requiring the

products of other bacteriaproducts of other bacteria Need to be cultured to understand their Need to be cultured to understand their

metabolism and ecological rolemetabolism and ecological role

Microbial DiversityMicrobial Diversity