The Prokaryotes: Domains Bacteria and Archaea
Bergey's manual groups the prokaryotes into two domains:
bacteria and archaea
mythical Greek god, Proteus, who could assume many shapes. Gram negative (-), chemoheterotrophic, the largest taxonomic group of bacteria.
unusual morphology, a group can utilize nutrients in a variety of ways and can be nitrogen fixating, chemoheterotrophs , or chemoautotrophs . have a distinct appearance because they display unique extensions called prosthecae.
are a characteristic of Alphaproteobacteria, which use these outward buds (picture outstretched arms) to increase their surface-to-volume ratio.
obligate intracellular parasites, gram negative (-) rods, transmitted by insects ot ticks. Ex: R.rickettsii Rocky Mountain Spotted Fever - transmitted by ticks.
often use nutrients that diffuse away from areas of anaerobic decomposition of organic matter (hydrogen gas; ammonia; methane). several important pathogenic bacteria belong to this group.
capable of degrading more than 100 different organic substances
pertussis (whooping cough)
usually inhabit the mucous membranes of mammals (gonorrhea; meningococcal meningitis)
live in symbiosis with many plant roots
Rocky Mountain Spotted Fever
Rickettsia, gram (-) rods
aerobic sewage treatment processes
largest subgroup of proteobacteria, gram (-), includes great variety of physiological types
Legionella (will be on test)
causes a form of pneumonia known as legionellosis
gram (-) rods; can grow in hospitals, on soap residues, cap-liner adhesives, and on antiseptics.
slightly curved rods; cholera; usually transmitted to humans via raw or undercooked shellfish
facultatively anaerobic, gram (-) rods; inhabit the intestinal tracts of humans and other animals (Enterotube tests)
E. coli - indicates fecal contamination
potentially pathogenic: can contaminate food; serotype testing for different varieties (typhoid fever; salmonellosis.
bacillary dysentery or shigellosis
may cause serious pneumonia in humans
swarming type of growth; urinary tract infections; infection in wounds
plague, prairie dogs and fleas
urinary tract infections
pathogen of domestic animals
Non-Proteobacteria Gram (-)
not related phylogenetically to the proteobacteria. include physiologically and morphologically distinctive photosynthesizing bacteria
Important contributors to the sulfur cycle, some are predators on other bacteria. Myxococcus - slime trails
helical or vibrioid (curved)
spontaneous abortion in domestic animals
require blood in media; common cause of meningitis in young children; frequent cause of earaches.
green sulfur and non-sulfur bacteria, carry out photosynthesis, some fix nitrogen(important to the environment), blue-green algae, morphology varies
anaerobic environments, habitat deep sediments of ponds and lakes. carry out photosynthesis (contains chlorophyll). anoxygenic do not produce oxygen. purple sulfur use H2S rather than O2. green sulfur- bacteria, purple nonsulfur use carbohydrates and acids instead of O2. green nonsulfur
no gram negative cocci, no peptidoglycan. Chlamydia common cause of blindness in humans (trachoma); also caused the sexually transmitted infection; transmitted by interpersonal contact or by airborne respiratory routes
use of axial filaments, treponema = causes syphilis,
Borrelia - causes relapsing fever & lime disease.
Leptospira - water contamination from animal urine (dog, cat, rat)
includes many anaerobes
Bacteroides - human intestinal tracts
anaerobic, pleomorphic, in the gums
Gram (+) Bacteria
Divided into two groups:
- High G + C ratio > 50%
- Low G + C ratio < 50% (firmicutes)
Low G + C Bacteria
- Mycoplasma (M. pneumoniae) lack cell, pleomorphic, very small, may pass through filters.
- Clostridium (C. botulinum) obligate anaerobes; tetnus, botulism, gangrene and diarrhea
- Bacillus (B. anthracis) rods that produce endospores; several species produce antibiotics (anthrax)
- Listeria (L. monocyteogenes)- food contamination
- Staphylococcus (S. aureus) grapelike clusters; facultative anaerobes infection of surgical wounds; toxic shock syndrome; food poisoning.
- Lactobacillus located in the vagina, intestinal tract, oral cavity; used to make sauerkraut, pickles, buttermilk, and yogurt. aero tolerant anaerobes
High G + C Bacteria
- Mycobacterium (M. tuberculosis) - aerobic, non-endospore-forming rods; acid-fast; drug resistant; waxy outer layer; tuberculosis, and leprosy
- Corynebacterium - pleomorphic diphteria
- Propionibacterium - used to make swiss cheese; acne
- Gardnerella - pleomorphic; vaginitis
- Frankia - causes formation of nitrogen fixing nodules to form in alder tree roots.
- Streptomyces - produces most of our antibiotics
- Actinomyces - mouth and throat of humans and animals
- Nocardia - mycetoma (destructive infection of the feet and hands
- Impetigo - caused by Strep or Staph
cell walls lack peptidoglycan, no known pathogen, some are unusual morphology, can divide by binary fisson of budding, can live in extreme environments
survive high salt concentrations > 25%
acid sulfur rich hot springs