Download 3. Phylum Proteobacteria 3.3. g-Proteobacteria

3. Phylum Proteobacteria
GRAM NEGATIVE BACTERIA
Wide morphological and metabolic diversity.
Clinical, environmental, and industrial relevance
Phylum with highest number of cultured representatives
5 groups (based on 16S rRNA): a, b, g, d, and e
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
2. Phylum Proteobacteria
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.1. a-Proteobacteria: Rhizobium
N2 fixing organisms:
FREE
LIVING
Some cyanobacteria (Bacteria)
Some anoxygenic phototrophs (Bacteria)
Some chemolithotrophs (Bacteria/Archaea)
Some chemoorganotrophs (Bacteria/Archaea)
SYMBIONTS Some chemoorganotrophs (Bacteria)
E.g. symbionts
of leguminous
plants
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.1. a-Proteobacteria: Rhizobium
RECOGNITION
NOD FACTORS
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.1. a-Proteobacteria: Rhizobium
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.1. a-Proteobacteria. Agrobacterium
pTi
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.1. a-Proteobacteria: “acetic acid bacteria”
They oxidize sugars and alcohols
Acidophilic
ETHANOL
ETHANAL
Gluconobacter
ACETIC ACID
e- e-
H20
O2
Acetobacter
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.1. a-Proteobacteria: Caulobacter
Prosthecae: cytoplasmic extrusions (stalks, hyphae, or appendages)
Budding division (mother cells retain their original identity)
Attachment, increased surface-to-volume ratio, reduced cell sinking
Aquatic bacteria (either planctonic or benthonic)
PROSTHECAE
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.2. b-Proteobacteria. Neisseria
Aerobic diplococcus
Penicillin sensitive
Pathogens and normal microbiota
Carrier state
N. meningitidis (“meningococcus”)
Aerosols
Nasopharynx
Blood stream:
Meningitis
(sudden onset of headheache, vomiting
and stiff neck)
Intravascular coagulation shock
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.2. b-Proteobacteria: Neisseria
N. gonorrhoeae (“gonococcus”)
- Very sensitive to environmental
stress (drying, sunlight, UV light…)
- High incidence (STD, ETS)
- Mild symptoms* in women
(asymptomatic carriers). PID
- Complications if untreated
Sexual contact
Mucous membranes of the
genitourinary tract
Reasons?
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.2. b-Proteobacteria. Acidithiobacillus
Chemolithotroph: donor: Fe2+ / acceptor: O2
They use large amounts of substrate (they fix CO2)
pH acidic (acidiphilic)
Acid mine drainage (formation of H2SO4 and Fe3+) (O2, water and
bacteria)
Thiobacillus
ferrooxidans
Biolixiviation
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.2. b-Proteobacterias. Zooglea
WASTEWATER
TREATMENT
BOD:
Biological Oxygen Demand
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacteria: Legionella
Rods
Complex nutritional requirements (Fe)
Resistent to b-lactamic
Terrestrial and aquatic habitats
Waterborne, aerosols (no person-to-person)
LEGIONELLOSIS
L. pneumophila
Pontiac fever
Pneumonia
Emerging disease (1976)
Cases per 100.000 inhabitants. Spain
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacteria: Legionella
Legionella inside an alveolar
macrophage
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacteria: Haemophilus
Haemophilus influenzae
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacteria: Pseudomonas
More than 100 species
Some species utilize over 100 different compounds
Aerobic chemoorganotrophic rods
• Some chemolitotroph (H2, CO)
• Some anaerobic (NO3- / fermentation)
Sugar oxidation: Entner-Doudoroff pathway
Fluorescent pigments
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacteria: Pseudomonas
Pseudomonas
aeruginosa
Opportunistic pathogen; intrahospitalary infections
Resistence plasmids (plasmids R)
Respiratory tract infections
Skin infections
Bacteremia
Endocarditis
Joint infections
Fastrointestinalinfections
UTI
Eye infections
CNS infections
Upper respiratory tract infections
Cystic fibrosis complications
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacteria: Pseudomonas
DEGRADATIVE
MEGAPLASMIDS
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacteria: Family Enterobacteriaceae
Enteric bacteria
Facultatively aerobic, gram negative rods
• Fermentation of sugars to organic acids
• Some respire NO3- to NO2- (never to N2)
Virulence factors and pathogenicity
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacteria: Family Enterobacteriaceae
Escherichia
Warm blooded animals
Gut microbiota (comensals)
Pathogenic strains:
E. coli enterotoxigenic (ECET)
E. coli enteropathogenic (ECEP)
E. coli enterohemorrhagic (ECEH) (STEC)
E. coli O157:H7
E. coli O104:H14
Gastroenteritis
Hemolytic uremic syndrom (HUS)
Urinary tract infections (UTI)
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
vitamin K
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacterias. Familia Enterobacteriaceae
Salmonella
Habitat: gastrointestinal tract of wild and domestic
animals, birds, pets, and insects. Zoonosis.
Main pathogenic serovars:
S. typhimurium: salmonellosis (enterocolitis)
S. typhi: typhoid fever
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacteria: Family Enterobacteriaceae
Shigella
Reservoir: infected gut
S. dysenteriae:
- Shigellosis or bacillary dysentery (“disentería bacilar”)
- HUS
Shigella cells invading intestinal
epithelium
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacteria: Family Enterobacteriaceae
Yersinia: Y. pestis PLAGUE (bubonic, pneumonic and speticemic). Zoonotic disease.
Gangrene and black spots (“black death”)
Buboes
(“bubones”)
Bacteria in lung tissue
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacterias: Vibrio
Curved and straight rods
Aquatic media
Many species, some pathogenic:
V. cholerae: cholera
CHOLERA TOXIN
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.3. g-Proteobacteria: Photobacterium
Autoinduction: “quorum sensing”
FMN
FMNH2 + O2 + RCHO
NADH
luciferase
FMN + RCOOH + H2O + luz
Inducer molecule: acyl homoserine lactone (AHL)
NAD+
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.4. d-Proteobacteria: Bdellovibrio
“Predator” of other bacteria
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.4. d-Proteobacteria: SULFATE (AND SULFUR) REDUCING BACTERIA (SRB)*
Desulfo- (generally) or Desulfuro-
They reduce sulfate/sulfur(acceptors)
Donors
H2
O. M.
Final products: H2S
Strict anaerobes (anoxic environments)
Group I:
Acetate cannot be used as donor
Sulfate reducing bacteria
Group II:
H2 and acetate can be used as donors
Sulfate reducing bacteria
Fixation of CO2 (acetil-CoA pathway)
Group III:
H2 or organic matter as donors
S and sulfite reducing bacteria (NEVER sulfate)
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
*Some sulfate-reducing bacteria are not delta-proteobacteria
3. Phylum Proteobacteria
3.4. d-Proteobacteria: SULFUR AND SULFATE REDUCING BACTERIA
m.o.
Marine sediments
O2
+0.8
NO3
-
Mn+4
E’ (V)
Fe+3
0
Consortia of SRB/methane oxidizing Archaea
SO4
-2
-0.2
CO2
Stratification of electronic acceptors
Limited organic matter
Most important metabolism: sulfate reduction
Competence (or not---) with methanogenic Archaea
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.4. d-Proteobacteria: MYXOBACTERIA
Vegetative cells: long rods without flagella (names: Myxo…). Gliding.
Fruiting bodies: cell-to-cell communication and differentiation
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.5. e-Proteobacteria: Campylobacter and Helicobacter (both microaerophilic)
Campylobacter: acute gastroenteritis, food borne disease (chicken meat…)
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
Helicobacter: gastritis and ulcers
http://www.nobelprize.org/nobel_prizes/medicine/laureates/2005/marshall-lecture.pdf
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
Nitrospira (independent phylum)
Nitrifying Archaea
3. Phylum Proteobacteria
3.6. OTHER PROTEOBACTERIA: NITRIFYING BACTERIA
a, b, g , and d Proteobacteria
Electron donors: NH4+ and NO2- / Acceptor: O2 (Nitroso…/ Nitro…)
They consume large amounts of substrate: chemolithoautotrops/ chemolithoheterotrophs
Soils and waters; ammonia-rich sites; leaching of NO3Nitrification
NH4+
Nitrosomonas
NO2-
NO3Nitrobacter
AMO: ammonia monooxygenase
NOR: nitrite oxidoreductase
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.6. OTHER PROTEOBACTERIA: SULFUR OXIDIZING BACTERIA
a, b, g, e Proteobacteria
Donors: H2S, S0, S2O32-, metallic suflides, H2 / Acceptor: O2 (sometimes NO3- )
S0 accumulation inside or outside the cell
Acidithiobacillus: acidiphilic (A. ferrooxidans FeS2, Fe2+); autotrophs
Thiomargarita: anaerobic oxidation (acceptor: NO3-)
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
Hydrothermal vents: H2S, H2, CO2, O2, N2...
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.6. OTHER PROTEOBACTERIA: PURPLE BACTERIA
Anoxygenic phototrophs
Reaction centre: bacteriochlorophylls
Antenna pigments: BChl + carotenoids
Photosynthetic systems: invaginations of
the cytoplasmatic membrane
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.6. OTHER PROTEOBACTERIA: PURPLE BACTERIA
ATP: Cyclic
photophosphorilation
Eo (-)
NAD(P)H: Reverse electronic flow
BChl
EXCITED
NAD(P)+
BChl EXCITED
e-
H+
cte-
NAD(P)H
cte-
H+
e-
H+
H+
eEo (+)
LIGHT
BChl
BChl
BASAL
BASAL
NO external electron donors for ATP
Images property of Fernando Santos
External electron donors for NAD(P)H
H2S
S0
Fe2+
S0
SO42Fe3+
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.6. OTHER PROTEOBACTERIA: PURPLE BACTERIA
g-Proteobacteria (“purple sulfur bacteria”): highly sensitive to O2; highly tolerant to [H2S]
S compounds as electron donors. Photoautotrophs (Calvin cycle) Photoheterotrophs
N2 fixers
a/b-Proteobacteria (“purple nonsulfur bacteria”): more tolerance to O2; very sensitive to
high [H2S]
Chenoorganotrophs, Photoheterotrophs, photoautotrophs
N2 fixers
Anoxic areas blooms
Sulfide-rich waters Meromictic lakes,
microbial mats
(SRB)
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
Metabolic diversity of nonsulfur
purple bacteria
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
Microbial mats: stratification of microbial populations driven by
environmental gradients
Images property of Fernando Santos
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.6. OTHER PROTEOBACTERIA: METHANOTROPHS
Methylotrophs vs. methanotrophs
Biotic and abiotic methane
Where does the methane come
from?
Methanotrophs vs. methanogens
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.6. OTHER PROTEOBACTERIA: METHANOTROPHS (Methylo…)
Type I
Type II
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
Methane as energy source
Methano
Methanol
Formalhehyde
CO2
Methane
monooxygenase
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
Methane as carbon source
Methane
Methanol
Type I
Formalhehyde
biomass
Type II
Ribulose
monophosph
ate pathway
Serine
pathway
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
3. Phylum Proteobacteria
3.6. OTHER PROTEOBACTERIA: RICKETTSIAS
a/g Proteobacteria
Obligate intracellular parasites*
Induce phagocytosis, do not survive outside hosts
Highly specific energy metabolism*, synthesize few compounds
Transmitted by arthropod vectors
Damage to blood vessels
Epidemic tifus (Rickettsia prowazekii) Vector: human louse
Rocky Mountains spotty fever (Rickettsia rickettsii) Vector: tick
*Q Fever (Coxiella) Vectors: tick, aerosols, dairy products
One bacteria is enough!! (Biological weapon)
Fever, headheach, weakness
Rash
Organ infections
High mortality untreated
L. 6: Bacteria Domain (II). 2nd Biology ARA 2013-2014
*Exception