α-proteobacteria

-includes many groups of plant and animal simbionts and pathogens

-Their intracellular habitat is due to the loss of major important 

pathways in energy metabolism and 

biosynthesis.

-totally dependent on the host cell for nutrients.

 -In insects, these intracellular symbionts can result in male sterility, and sex and behavioral changes.

-Mitochondria came from this group

Agrobacterium tumiefaciens

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-Rod shaped plant pathogen

-ability to cause tumors based on the presence of a virulence factor, the Ti plasmid

-plasmid itself is used in experimental genetic manipulation of plants, to transfer foreign genes into plant cells. 

-Gram Negative Bacteria

Rhizobium

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-common in soil and lives in rhizosphere (around plant 

roots)

-affects root hairs of legumes and multiply inside root cells

-Multiplication of bacterial cells in the root 

hairs results in the formation of nodules that 

resemble tumors

-the bacteria converts nitrogen to ammonia in nitrogen fixation

-relationship is symbiotic because the plant uses the ammonia for amino acids and excess is used for soil for other plants

Rickettsia rickettsii

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-Gram negative bacteria

-causes rocky mountain spotted fever

-transmitted by dermancater ticks (inc.Dog tick, rocky mountain wood tick)

-intracellular pathogen in animals

-symptoms- fever and rash on ankles and wrists

This Gram-negative group is mainly found in 

soil and water, and some members are 

pathogenic to animals.

Neisseria gonorrhoeae

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-GRAM NEGATIVE β-proteobacteria

-SEXUALLY TRANSMITTED DISEASE

-COCCI SHAPED(FOUND IN PAIRS)

-HAS ANTIGENIC VARIATION OF FIMBRIAE AND A PROTEASE THAT DESTROYS LGA(WHITE BLOOD CELLS)

SOME PATIENTS ARE ASYMPTOMATIC

Neisseria gonorrhoeae

(in women)

gonorrhea is characterized by 

painful urination, yellowish discharge, and 

bleeding during intercourse.

Neisseria gonorrhoeae

in men

painful urination, and a white or 

green discharge from the penis, or 

occasional testicular swelling

Neisseria gonorrhoeae

in infants

Newborns can contract the organism from 

the mother during birth, leading to eye 

infections (neonatal ophthalmia). Antibiotic 

or silver nitrate drops are put in the 

newborn's eyes to prevent such infections.

can lead to PID (pelvic 

inflammatory disease) and infertility in 

women.  Males have a higher risk of bladder 

cancer. Other sequelae include meningitis 

and autoimmune arthritis 

Neisseria meningitidis

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-gram negative β-proteobacteria

-cocci in pairs (many organisms have these in nasophrynx without symptoms)

-causes imflammation of menegies and spinal cord

-symptoms- headache, stiffneck, fever, confusion, and dizziness

-during infection its found in cerebralspinal fluid (appears cloudy due to luekocytes and bacteria)

-can also spread to bloodstream through respirtory tract

This is a very large group of microbes. 

Many members of this group are facultative 

anaerobes, and often associated with the 

intestines of animals.

Pseudomonas aeruginosa

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-gram negative  γ-proteobacteria

-short rod with flagella (swims rapidly)

-common in soil and water

-able to form biofilms (microbial communities growing on a surface)

-can grow on petroleum and detergents

-resistant to germicides and antibiotics

-cause oppurtunistic infections in burn patients producing a blue-green pigment when growing on the skin, also affects lungs of cistic fibrosis patients

-able to survive high tempertures and can cause "hot tub dematitis"

Vibrio cholerae

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-Gram negative γ-proteobacteria

-comma