Unit IV.B The Prokaryotes (Gram-Negative Proteobacteria)

Question 1

include most of the gramnegative, chemoheterotrophic bacteria, are presumed to have arisen from a common photosynthetic ancestor

Answer 1

proteobacteria

Question 2

Five Classes of Gram-Negative Proteobacteria

Answer 2

1.Alphaproteobacteria
2.Betaproteobacteria
3.Gammaproteobacteria
4.Deltaproteobacteria
5.Epsilonproteobacteria

Question 3

• includes most of the proteobacteria that are capable of growth with very low levels of nutrients. Some have unusual morphology, including protrusions such as stalks or buds known as** prosthecae.**
• also include agriculturally important bacteria capable of** nitrogen fixation** in symbiosis with plants, and several plant and human pathogens.

Answer 3

The α (alpha) Proteobacteria

Question 4

• most abundant microorganisms on Earth, certainly in the ocean environment
• member of a group of marine microbes named SAR 11 → Sargasso Sea.
• extremely small (~0.3nm) → survive in low nutrient environments

Answer 4

Pelagibacter

Question 5

• Nitrogen-fixing bateria
• a soil bacterium that grows in close association with the roots of many plants,
• It uses nutrients excreted by the plants and in return fixes nitrogen from the atmosphere.

Answer 5

Azospirillum

Question 6

Produce acetic acid from ethyl alcohol
Acetobacter & Gluconobacter - Industrially important aerobic organisms that convert ethanol into acetic acid (vinegar).
Granulibacter - emerging pathogen found in patients with chronic granulomatous disease

Answer 6

Acetobactereceae

Question 7

• Obligate intracellular parasites (reproduce only within a mammalian cell)
• that they are transmitted to humans by insect and tick bites
• Arthropod-borne, spotted fevers

Answer 7

Rickettsia

Question 8

• Obligate intracellular parasites
• transmitted by ticks to humans and cause ehrlichiosis, a sometimes fatal disease
• Tick-born, live obligately within white blood cells

Answer 8

Ehrlichia

Question 9

• Have prosthecae that increases their nutrient uptake because they are exposed to a continuously changing flow of water and because the stalk increases the surface-to-volume ratio of the cell

Answer 9

Caulobacter

Question 10

• Have prosthecae
• Hyphomicrobium. Budding bacteria found in lakes
• found in low-nutrient aquatic environments and have even been found growing in laboratory water baths.

Answer 10

Hyphomicrobium

Question 11

• Plant pathogen
• infect the roots of leguminous plants
• known by the common name of rhizobia. The presence of rhizobia in the roots leads to formation of nodules in which the rhizobia and plant form a symbiotic relationship, resulting in the fixation of nitrogen from the air for use by the plant

Answer 11

Rhizobium & Bradyrhizobium

Question 12

• Human pathogen
• B. hensela e- Cat-scratch disease

Answer 12

Bartonella

Question 13

Human Pathogen
small nonmotile coccobacilli & obligate parasites of mammals
Brucellosis
B. abortus (cattle), B. canis (dogs), B. suis (pigs), B. melitensis (sheep & goats)

Answer 13

Brucella

Question 14

genera of nitrifying bacteria that are of great importance to the environment and to agriculture.

Answer 14

Nitrobacter and Nitrosomonas

Question 15

• Obligate intracellular parasites
• most common infectious bacterial genus in the world; they live only inside the cells of their hosts, usually insects
• → dengue & Zika viruses control

Answer 15

Wolbachia

Question 16

constitute the largest subgroup of the proteobacteria and include a great variety of physiological types.

Answer 16

The γ (gamma) Proteobacteria

Question 17

• Chemoautotrophic, oxidize hydrogen sulfide (H2S) to elemental sulfur (S0) for energy
• esembles certain filamentous cyanobacteria ,but it is not photosynthetic
•  Its motility is enabled by the production of slime, which attaches to the surface on which movement occurs and provides lubrication, allowing the organism to glide.

Answer 17

Beggiatoa

Order Thiotrichales

Question 18

• Chemoheterotrophic
• a genus of small, pleomorphic bacteria that grow only on complex media enriched with blood or tissue extracts
• F. tularensis: cause tularemia or deerfly fever

Answer 18

Francisella

Order Thiotrichales

Question 19

aerobic rods or cocci, Opportunistic pathogens, Metabolically diverse, Polar flagella, Excrete extracellular, water-soluble pigments that diffuse into their media
very common in soil and other natural environments

Answer 19

Pseudomonas

Pseudomonadales Order

Question 20

nitrogen-fixing bacteria, free-living in soil

Answer 20

Azotobacter and Azomonas

Pseudomonadales Order

Question 21

• are strictly aerobic coccobacilli—that is, intermediate in shape between cocci and rods.
• (Moraxella lacunata is implicated in conjunctivitis, an inflammation of the conjunctiva, the membrane that covers the eye and lines of the eyelids)

Answer 21

Moraxella

Pseudomonadales Order

Question 22

• A. baumanii - resistant to most available antibiotics; respiratory pathogen but it also infects skin, soft tissues, and wounds and occasionally invades the bloodstream

Answer 22

Acinetobacter

Pseudomonadales Order

Question 23

• Found in streams, warm-water pipes, cooling towers
• L. Pneumophilia - Legionaire’s disease (pneumonia-type) & Pontiac fever (flu-like)

Answer 23

Legionella

Legionaellales Order

Question 24

this bacteria require a mammalian host cell to reproduce.

Answer 24

Coxiella

Legionaellales Order

Question 25

* Facultative anaerobic rods that are often slightly curved * Found in coastal water

Answer 25

Vibrionales Order

Question 26

* causes cholera. The disease is characterized by a profuse and watery diarrhea. * auses a less serious form of gastroenteritis.

Answer 26

* Vibrio cholerae * V. parahaemolyticus

Question 27

they inhabit the intestinal tracts of humans and other animals.

Answer 27

Enterobacteriales Order

Question 28

* a common inhabitant of the human intestinal tract and is probably the most familiar organism in microbiology * Laboratory pet * not usually pathogenic

Answer 28

Escherichia coli ( E. coli O157:H7) | Enterobacteriales Order

Question 29

* Mostly are pathogenic * Inhabit intestinal tracts of many animals, especially poultry and cattle & can contaminate food

Answer 29

Salmonella | Enterobacteriales Order

Question 30

* Found only in humans * bacillary dysentery or shigellosis

Answer 30

Shigella | Enterobacteriales Order

Question 31

* Found in soil or water * Nitrogen fixation * K. pneumoniae cause serious form of pneumonia in humans.

Answer 31

Klebsiella | Enterobacteriales Order

Question 32

* This genus of bacteria is implicated in many infections of the** urinary tract and in wounds.**

Answer 32

Proteus | Enterobacteriales Order

Question 33

* Y. pestis causes plague, carries by rats and ground squirrels; fleas transmit it among animals and to humans.

Answer 33

Yersinia | Enterobacteriales Order

Question 34

* Plant pathogens plant soft-rot disease * produce enzymes that hydrolyze the pectin between individual plant cells → plant cells to separate from each other → soft-rot

Answer 34

Erwinia | Enterobacteriales Order

Question 35

Enterobacteriales Order* E. cloacae & E. aerogenes: urinary tract infections and healthcare-associated infections. * **Distributed in humans and animals, as well as in water, sewage, and soil.**

Answer 35

Enterobacter | Enterobacteriales Order

Question 36

* facultative anaerobic, motile, and with seven species * C. sakazakii: meningitis and necrotizing enterocolitis in infants

Answer 36

Cronobacter | Enterobacteriales Order

Question 37

nonmotile; they are best known as human and animal pathogens.

Answer 37

Pasteurellales Order

Question 38

* pathogen of domestic animals * Cause pneumonia and septicemia * P. multocida: be transmitted to humans by dog and cat bites.

Answer 38

Pasteurella | Pasteurellales Order

Question 39

inhabit the mucous membranes of the upper respiratory tract, mouth, vagina, and intestinal tract.

Answer 39

Haemophilus | Pasteurellales Order

Question 40

distinctive in that they include some bacteria that are** predators on other bacteria**

Answer 40

The δ (delta) Proteobacteria

Question 41

* Prey on other bacteria * use H2S either as part of photosynthesis or as an autotrophic energy source

Answer 41

Bdellovibrio

Question 42

* Use oxidized forms of sulfur, such as sulfates (SO42-) or elemental sulfur (S0)instead of O2 as final electron acceptor→ H2S * found in anaerobic sediments and in the intestinal tracts of humans and animals

Answer 42

Desulfovibrionales

Question 43

* Fruiting & Gliding. Vegetative cells of the myxobacteria (myxo = mucus) move by gliding and leave behind a slime trail. * Myxococcus xanthus & M. fulvus - as they move, their source of nutrition is the bacteria they encounter, enzymatically lyse, and digest

Answer 43

Myxococcales

Question 44

resting cells of myxococcales

Answer 44

myxospores

Question 45

slender gram-negative rods that are helical or curved. There are two important genera, both of which are motile by means of flagella and are microaerophilic.

Answer 45

The ε (epsilon) Proteobacteria

Question 46

* microaerophilic vibrios * each cell has one polar flagellum * C. fetus: causes spontaneous abortion in domestic animals. * C. jejuni: is a leading cause of outbreaks of foodborne intestinal disease.

Answer 46

Campylobacter

Question 47

* Microaerophilic curved rods * Multiple flagella * Helicobacter pylori : most common cause of peptic ulcers in humans, cause of stomach cancer

Answer 47

Helicobacter