A LPHAPROTEOBACTERIA Danielle Miller Madison Klug.
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Transcript of A LPHAPROTEOBACTERIA Danielle Miller Madison Klug.
ALPHAPROTEOBACTERIADanielle Miller
Madison Klug
PHYLUM PROTEOBACTERIA Includes most of the gram
negative chemoheterotrophic bacteria
Presumed to have arisen from a common photosynthetic ancestor
Largest taxonomic group of bacteria
Few are now photosynthetic- other metabolic and nutritional capacities have arisen to replace this characteristic
Name “Proteobacteria” taken from the mythological Greek god Proteus, who could assume many shapes
PROTEOBACTERIA CLASSES
Proteobacteria are separated into five classes designated by Greek letters: Alphaproteobacteria Betaproteobacteria Gammaproteobacteria Deltaproteobacteria Epsilonproteobacteria
OVERVIEW Proteobacteria
Alphaproteobacteria Caulobacterales Rickettisiales
Rickettsia Epidemic Typhus Rocky Mountain Spotted Fever
Ehrlichia Ehrlichiosis
Rhizobiales Bartonella
Cat Scratch Disease Brucella
Brucellosis Rhodospirillales
Betaproteobacteria Gammaproteobacteria Deltaproteobacteria Epsilonproteobacteria
ALPHAPROTEOBACTERIA
Gram Negative Adopt an intracellular life-style
Plant mutualists Plant and animal pathogens Contains most of the proteobacteria that are
capable of growth at very low levels of nutrients.
Most abundant of marine cellular organisms Variety of metabolic strategies: Photosynthesis Nitrogen Fixation Ammonia oxidation Methylotrophy
ALPHAPROTEOBACTERIA
Morphologies: Stellate Spiral Prosthecae
Ancestral group for mitochondria Rickettsiales
DICHOTOMOUS KEY
ALPHAPROTEOBACTERIAOrder Important Genera Special Features
Caulobacterales Caulobacter Stalked
Rickettsiales -Ehrlichia-Rickettsia-Wolbachia
-Obligately intracellular human pathogens.-Obligately intracellular human pathogens. -Symbionts of insects.
Rhizobiales -Agrobacterium-Bartonella-Beijerinckia-Bradyrhizobium-Brucella-Hyphomicrobium-Nitrobacter-Rhizobium
-Plant pathogens.-Human pathogens.-Free-living nitrogen fixers.-Symbiotic nitrogen fixers.-Human Pathogens.-Budding-Nitrifying-Symbiotic nitrogen fixers
Rhodospirllales -Acetobacter-Azospirillum-Gluconobacter-Rhodospirillum
-Acetic acid producers. -Nitrogen fixers. -Acetic acid producers. -Photosynthetic, anoxygenic.
ORDER CAULOBACTERALES
Found in low nutrient aquatic environments, such as lakes
Feature stalks that anchor the organisms to surfaces Increases their nutrient
uptake because they are exposed to a continuously changing flow of water
Can use the host’s excretions as nutrients
ORDER RICKETTSIALES- GENUS RICKETTSIA
Gram-negative rod shaped bacteria
Enter their host cell by inducing phagocytosis
They quickly enter the cytoplasm of the cell and begin reproducing by binary fission
Survival depends on entry, growth and replication within the cytoplasm of eukaryotic host cells
Thought to be the closest living relatives that were the origin of the mitochondria organelles
ORDER RICKETTSIALES- GENUS RICKETTSIA
Obligate intracellular parasites- they reproduce only within a mammalian cell
Can only grow in tissue cultures or embryos
Infections damage the permeability of blood capillaries, which results in a characteristic spotted rash
Two clinical groups: Typhus Group Spotted Fever Group
EPIDEMIC TYPHUS (TYPHUS GROUP) Caused by Rickettsia
prowazekii Transmitted by human
body lice and the ectoparasites of flying squirrels
R. prowazekii grows in the louse's gut and is excreted in its feces. The disease is then
transmitted to an uninfected human who scratches the louse bite and rubs the feces into the wound.
EPIDEMIC TYPHUS (TYPHUS GROUP) Occurs in communities and
populations where body lice are prevalent
Outbreaks have often been tied to periods of war, poverty, and natural disasters, especially during the colder months when infested clothing is not laundered
Symptoms: Headache, chills, fever,
confusion, rash, photophobia.
Rash begins on the chest about five days after the fever appears, and spreads.
Treatment: antibiotics Infection can also be
prevented with vaccination
ROCKY MOUNTAIN SPOTTED FEVER (SPOTTED FEVER GROUP) Caused by Rickettsia
rickettsii Most lethal and most
frequent of the Spotted Fever diseases
Transmitted by the American Dog Tick, Brown Dog Tick and the Rocky Mountain Wood Tick They serve as both
reservoirs and vectors of the disease
Transmitted through saliva while the tick is feeding on the blood of the host
ROCKY MOUNTAIN SPOTTED FEVER (SPOTTED FEVER GROUP)
Symptoms: Fever, headache,
nausea, muscular pain and a severe rash that develops 2-3 days after the onset of fever
Treatment: Antibiotic treatment
needed immediately- Doxycycline (most effective when started before the 5th day of onset)
More severe cases may require longer periods of antibiotic treatment
ORDER RICKETTSIALES-GENUS EHRLICHIA
Gram-negative, rickettsia-like bacteria
Live obligately within white blood cells
Ehrlichia species are transmitted by ticks to humans and cause ehrlichiosis
the general name used to describe several bacterial diseases that affect animals and humans
EHRLICHIOSIS Human ehrlichiosis:
caused by at least three different ehrlichial species in the United States: Ehrlichia chaffeensis Ehrlichia ewingii Ehrlichia muris-like
Ehrlichiae are transmitted to humans by the bite of an infected tick.
The lone star tick is the primary vector of both Ehrlichia chaffeensis and Ehrlichia ewingii
EHRLICHIOSIS Symptoms:
fever, headache, fatigue, and muscle aches. symptoms occur within 1-2 weeks following a tick bite Skin rash is not considered a common feature of
ehrlichiosis, and should not be used to rule in or rule out an infection
Some patients may develop a rash that resembles the rash of Rocky Mountain spotted fever making these two diseases difficult to differentiate on the basis of clinical signs alone
Treatment: doxycycline Antibiotic treatment in a class of medications called tetracycline
antibiotics It works by preventing the growth and spread of
bacteria.
ORDER RHIZOBIALES
Variety of strategies to adapt and exploit niches. Capable of fixing
nitrogen in symbiosis with leguminous plants
Obligate and facultative intracellular bacteria and plant and animal pathogens.
Clinical Genera: Bartonella Brucella
GENUS BARTONELLA
Gram-negative bacillus Bartonella henselae Aka: Cat Scratch Disease
(CSD) Vector: Cat
Show no sign Transmission: scratches, bites, saliva At point of injury a mild infection occurs.
CAT SCRATCH DISEASE
Symptoms: Lymph node swelling near
site of bite or scratch. Can create a tunnel through
the skin and leak fluid. Headache, fever, fatigue,
etc. Treatments:
Usually not needed. Antibiotics, like azithromycin
can be helpful.
GENUS BRUCELLA
Small, non-motile coccobacilli
Obligate parasites of mammals
Ability to survive phagocytosis.
Usually passed around animals, causing disease in many different vertebrates
Cause the disease brucellosis
BRUCELLOSIS Route of Transmission:
GI track Respiration Skin wounds
Disease Symptoms: Fever, sweats, headaches, back pains, and
physical weakness. Severe infections of the central nervous
systems or lining of the heart may occur. Treatments:
Usually, doxycycline and rifampin are used in combination for 6 weeks to prevent reoccurring infection.
Depending on the timing of treatment and severity of illness, recovery may take a few weeks to several months.
ORDER RHODOSPIRILLALES
RHODOSPIRILLALES
Azospirillum: Soil bacteria Uses nutrients excreted by plants and in return
fixes nitrogen from the atmosphere. Acetobacter and Gluconobacter:
Industrially important aerobic organisms Convert EtOH into acetic acid (Vinegar)
Rhodospirillum: Photosynthetic
REFERENCES http://www.cdc.gov/rmsf/
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002581/
http://www.cdc.gov/healthypets/diseases/catscratch.htm
http://wwwnc.cdc.gov/travel/yellowbook/2010/chapter-5/rickettsial-and-related-infections.aspx
http://www.cdc.gov/Ehrlichiosis/symptoms/index.html
http://www.cdc.gov/ncidod/dbmd/diseaseinfo/brucellosis_g.htm
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000563/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1913456/#__sec17
Carvalho, F., Souza, R., Barcellos, F., Hungria, M., & Vasconcelos, A. (2010). Genomic and evolutionary comparisons of diazotrophic and pathogenic bacteria of the order Rhizobiales. BMC Microbiology, 101-15. doi:10.1186/1471-2180-10-37
http://permaculturetokyo.blogspot.com/2009/02/rhizobium-symbiosis-with-woody-plants.html
http://www.nlm.nih.gov/medlineplus/ency/article/001614.htm
http://www.cdc.gov/ncidod/dbmd/diseaseinfo/brucellosis_g.htm
http://medconditions.net/rhodospirillales.html
Tortora, Gerard J., Berdell R. Funke, and Christine L. Case. Microbiology: an Introduction. San Francisco, CA: Pearson Benjamin Cummings, 2010.