The Prokaryotes Domains Bacteria and Archaea

Question 1

According to Bergey’s Manual of Systematics of Archaea and Bacteria, how many phyla of bacteria and Archaea are there? What is phyla based on?

Answer 1

Bergey’s Manual of Systemaitcs of Archaea and Bacteria recognizes 42 phyla of Bacteria and 4 phyla of Archaea
Phyla are based on rRNA sequences. Considerable phenotypic diversity remains among members of some phyla

Question 2

Name all of the phyla of bacteria and Archaea ? What do names in parentheses represent?

Answer 2

42 phyla of bacteria
1. Acidobacteria
2. *Actinobacteria (Actionmycetota) Aquificae
3. *Bacteriodetes (bacteroidota)
4. *Chlamydiae (chlamydiota)
5. *Chlorobi (chlorobiota)
6. *Chloroflexi (Chloroflexota Chrysiogenetes
7. *Cyanobacteria
8. Deferribacteres
9. *Deinococcus-Thermus (Deinococcota)
10. Dictyoglomi
11. Fibrobacteres
12. *Firmicutes (Bacillota)
13. *Fusobacteria (Fusobacteriota)
14. Gemmatimonadetes
15. Lentilsphaerae (2004)
16. Nitrospirae
17. *Planctomycetes (planctomycetota)
18. Proteobacteria (pseudomonadota)
19. Spirochaetes
20. Synergistestes (2009)
21. **Tenericutes (1984) (planctomycetota)
22. Thermodesulfobacteria
23. Thermomicrobia
24. Thermotogae
25. Verrucombria
*15 New phyla (2009-2220)
Archaea
- Crenarchaeota
Euryarcheota
**Nanoarcheota (2002)
**Thaumarchaeota (2008)
The names in parentheses are NEW names given for the phyla

Question 3

What are the characteristics for Phylum proteobacteria? What kind of bacteria are they and how they get their energy sources?

Answer 3

General characteristics for Phylum Proteobacteria:
-LARGEST TAXONOMIC GROUP of bacteria containing mostly chmeoheterotrophic bacteria that are all Gram-NEGATIVE
-Named after Proteus, A greek god of the sea (name reflects the great diversity of forms found in this phylum)
-Consists of five classes designated by greek letters
(Alpha, beta, gamma, delta, and epilson proteobacteria).

Question 4

Which phylum has the largest taxonomic group of bacteria?

Answer 4

Phylum Proteobacteria

Question 5

Describe the different genera and special features for the phylum Alphaproteobacteria?

Answer 5

Alphaproteobacteria:
Important Genera
1. Caulobacter–> special features: Stalked
2. Ehrlichia –> Special features: obligatory intracellular human pathogens
3. Peleagibacter–> Special features: one of the most abundant microbes
4. Ricksettia–> special features: obligatory intracellular human pathogens
5. Wolbachia–> Special feature: Symbionts of insects
6. Agrobacterium—> special features: Plant pathogens
7. Bartonella–> special features: Human pathogens
8. Bradyrhizobium –> special features: symbiotic nitrogen fixers
9. Brucella –> special features: Human pathogens
10. Hyphomicrobium–> special features: Budding
11. Nitrobacter–> special features: Nitrifying
12. Rhizobium–> special features: symbiotic nitrogen fixers
13. Azosprilum—> Special feature: Nitrogen fixers

Question 6

Describe the characteristics for Pelagibacter? What phylum is It under? How does it gain energy?

Answer 6

Pelagibacter –> phylum Alphaproteobacteria
-Pelagus (“sea”) + bacteria (“Bacterium”) means “bacterium of the sea”
-A single marine species, P. ubique (ubiquitous) has been isolated
-one of the most Abundant microbes on Earth
**accounts for 25% of the ocean bacteria and combined weight > all of the fish
-Survives in a Low nutrient environment where its minimal genome and SMALL size, are advantageous
-One of the smallest (0.3 um diameter), simplest (1,354 genes) Autonomously replicating cells
-Shortest intergenic species, no duplicate gene copies, viral genes, or junk DNA
-Gains energy by respiring organic carbon or using a light driven proton pump (don’t fix C)

Question 7

How does a small cell size provide a competitive Advantage? What occurs with cells that get bigger?

Answer 7

Small cells size will have a HIGHER Surface area/Volume that allows the cells to move materials in and out more efficiently
-Smaller cells have higher SA/Vol. ratios
-For cells to get bigger, that is, for their volume to increase, intracellular transport must somehow become independent of diffusion.

Question 8

Discuss characteristics for Caulobacter and Hyphomicrobium. Discuss the similiarities and differences between each groups. how does Caulobacter differ?

Answer 8

Alphaproteobacteria (phylum)
Caulobacter and Hyphomicrobium:
-BOTH found in Low-nutrient aquatic environments (ex: lakes) produce prominent prostheca (Cytoplasmic extrusion bounded by the cell wall (ex: stalk or hypha) who size increases when nutrient conditions drop to increase nutrient acquisition and have a dimorphic cycle
-Caulobacter produce stalks for anchoring to surfaces and increasing surface to volume ratios (both facilitate nutrient uptake)

Question 9

differentiate between how Caulobacteria and Hypomicrobium replicate?

Answer 9

Caulobacter replicates by BINARY FISSION
Hyphomicrobium replicates by BUDDING at Hyphal tips

Question 10

Describe what occurs in the Caulobacter life cycle? How does this process occur? What must happens for reproduction of cells to occur?

Answer 10

Caulobacter life cycle:
Morphogenic events are an INTRINSIC part of the Caulobacter cell cycle. Caulobacter is motile for part of its life, then the flagella is Lost, and a stalk is formed.
** Following surface attachment, reproduction can occur, resulting in one stalked cell and one flagellated swarmer cell*
process:
1. have Flagellated swarmer cells (that CANT Replicate)
2. Flagellum is lost
3. Stalk begins tor form when the organism attached to surface
4. Stalk elongates,
5. Division begins, flagellum forms on new cell
6. New cell with flagellum swims off as swarmer cell (cannot replicate)
-Stalked cell initiates with new round replication

Question 11

Describe the life cycle of hyphomicrobrium? What is the process lke?

Answer 11

Th Life Cycle of Hyphomicrobrium
-It has been theorized , but Not demonstrated that. hyphomicrobium cell adheres to surfaces via a polar holdfirst opposite they hypha
-The Hypha of hyphomicrobirum, unlike a stalk, develops further as part of reproductive cycle
process;
1. Mother cell formed
2. hypha formation
3. DNA replication followed by migration of one chromosome into lengthening hypha
4. Terminal bud becomes separated by cross-wall
5. Mother cell undergoes further DNA replication and bud information
6. flagellum formation
7. Daughter (swarmer cell)

Question 12

What are the two main Nitrogen fixing bacteria under phylum Alphaproteobacteria? What are their characteristics?

Answer 12

Nitrogen fixing Bacteria
1. Rhizobium (+ 4 other genera)
-ALL known by the common name rhizobia
-enter the roots of leguminous plants (beans, peas, clover) and form nodules
-Fix N2 in an endosymbiotic relationship with the plant
(get energy and nutrients from plant, and plant will fix nitrogen)
-CANNOT fix Nitrogen independently

2. Azospirillum
   -A free living, plant root surface colonizing soil bacterium commonly found on tropical grasses and sugar cane
   -use nutrients excreted by plants and fixes nitrogen in return (Associative relationship)
   prefix “Azo” means “without life”. Nitrogen is associated with the term “Azo”, which is frequently used in the names of nitrogen fixing genera

Question 13

Describe the characteristics of Agrobacterium? What phylum does it belong to? What is an example of a species?

Answer 13

Agrobacterium
-Plant pathogens
-Invade plants cells but do NOT induce nodules to fix Nitrogen
- A. tumefaciens induces crown gall disease in plants through the insertion of T-DNA form its Ti-plasmid into the plants genome
(from phylum Alphaproteobacteria)

Question 14

What are the Nitrifying bacteria that are apart of Alphaproteobacteria? What are their characteristics? Why is nitrate production important? What class is Nitrosomonas apart of?

Answer 14

Nitrifying bacteria
-Nitrobacter and Nitrosomonas
-Chemoautrophs (oxidize nitrogen for energy and fix CO2)
*Nitrosomonas: NH4+ –> NO2-
Nitrobacter: NO2- –> NO3-
Taken together, this is called nitrification
-NITRATE (NO3-) production is critical for the environment and agriculture because they are mobile in the soil and more efficiently absorbed from the soil by plants than either nitrite or ammonium ions
*Nitrosomonas is a member of the Beta proteobacteira class
(nitrite is NO2-)

Question 15

Explain what occurs in the Nitrogen cycle. Which bacterial species is involved in Nitrification vs Denitrification?

Answer 15

Nitrogen cycle:
Different bacteria interconvert between compounds
-Oxidations that occur, to allow bacteria to generate energy
-Nitrosomonas (and also some archaea) will convert NH4+ (ammonia) to Nitrite (NO2-) by oxidation
Nitrification process will occur where NH4 is converted to NO2- (Oxidized) and then Nitrite is converted to Nitrate (NO3-) by Oxidation?
-Nitrobacter will convert NO2- (+3) to NO3- (+5)
-During Denitrification (reduction), Thiomargarita namibiensis will convert NO3- (+5) (nitrate) to NO (+2) and then convert NO (+2) to N2 (0). This is an anaerobic process
-Nitrogen fixation will convert N2 (0) to NH4+ (-3) through reduction
Nitrification is Aerobic and Denitrification is Anaerobic
REVIEW

Question 16

which two genera that are part of class Alphaproteobacteria have facultative intracellular parasites? What about Obligate intracellular parasites?

Answer 16

Under class Alphaproteobacteria:
Facultative intracellular parasites are under genus Bartonella and Brucella
obligate intracellular parasites: Ricksettia, and Ehrlichia

obligate intracellular parasites: can only grow and reproduce INSIDE the host cell
Facultative intracellular parasites: microbes that can Reproduce outside or inside the cells

Question 17

Describe the characteristics for the genus Bartonella. What kind of parasites exist and what is an example of a species commonly seen? What percentage of cat’s carry a particular parasite?

Answer 17

Aphaproteobacteria (class)
Bartonella (genus) :
-Faculative intracellular parasites (microbes that can reproduce outside or inside cells)
-Several species are Human pathogens
-B. henselae - cats most commonly acquire from infected flea bites. The bacillus inhabits the Cat’s red blood cells (cells are outwardly sick)
-Cats are also carriers and the primary mode of transmission to humans is INFECTED Flea FECES. Transferred when a cat licks an open wound, bites, or scratches. Causes cat-scratch disease/fever (more common than Lyme disease in the U.S)
-40% of cats carry B. henselae in their mouths or under their claws

Question 18

Describe the characteristics for the genus Brucella. what king of parasites exist. What kind of disease can Aris and how is it transmitted?

Answer 18

Alphaproteobacteria:
Brucella (genus)
Facultative intracellular parasites
-causes Brucellosis
-different species that mainly infect cattle, swine, goats, sheep and dogs, and may also infect humans.
-spreads to humans by contact with animals, ingestion of undercooked meat or UNPASTEURIZED Dairy products
-Following phagocytosis by macrophages, the parasite is able to survive in phagosomes by BLOCKING Lysosomal fusion *
* B. melitensis also affects sheep*

Question 19

What are the characteristics of the genus Ricksettia? What makes it unique? How does it infect animals and humans? What are examples of species for Rickettsia and what disease do they cause? What kind of parasites are seen?

Answer 19

Alphaproteobacteria (class)
Rickettsia (genus):
-Obligate intracellular parasite (can only grow and reproduce inside host cells)
-Highly Pleomorphic bacteria (rods or coccobacilli)
-transmitted to humans by Insect and tick bites
-preferentially infect endothelial cells lining the small blood vessel by inducing phagocytosis. They escape the phagosome and enter the cytosol, where they replicate
-They cause several diseases know as Spotted severe group
R. prowazekii: Lice–> Epidemic typhus
R. typhi: rat fleas —> Endemic murine typhus
R. ricksetti: ticks–>Rocky Mountain spotted fever

Question 20

What are features of the genus Ehlichia? what kind of parasites are seen and how is this transmitted to humans. Explain mode of tranmission

Answer 20

Alphaproteobacteria
Ehrlichia (genus):
-Rickettsia-like bacteria
-transmitted by ticks to humans and cause ehrlichiosis
-After phagocytosis by macrophages, able to survive in phagosomes by blocking lysosomal fusion

Process
(1. Ehrlichia infection of any leukocyte by phagocytosis
2. Formation of phagocytic vesicle
3. Bacterium survives and multiplies in phagosome. phagosome-lysosome fusion inhibited
4. Cell and phagosome lyses )

Question 21

Describe the characteristics for genus Wolbachia? What makes it unique? What percentage of insects are affected by this Wolbachia?

Answer 21

Alphaproteobacteria (class)
Wolbachia
-Endosymbiont
-NOT human pathogens, but may be the MOST COMMON infectious bacterial genus on earth (infecting over a million species)
-Live as ENDOSYMBIONTS in the Cells of Insects and other inverterbrates
-20-75% of all insects are infected
-its interactions with its hosts are complex, interfering with reproduction and egg development in infected insects

Question 22

What is another important use for Wolbachia?

Answer 22

Wolbachia used for BIOLOGICAL CONTROL
(ex: controlling mosquitos, reducing their reproduction ? )
REVIEW

Question 23

Where would Pelagibacter be placed in Dichotomous key for alphaproteobacteria (discussed in chapter 11)?

Answer 23

Pelagibacter would be placed in bottom right after categories:
-NOT cause disease in human s
-Does NOT live in insects
-Does NOT have prosthecae
-NOT chemoautrotrophic (cells that make their own energy by oxidizing inorganic compounds)
-NOT a plant pathogen
-Does NOT fix Nitrogen

Question 24

Describe the features that all species share under the class Betaproteobacteria. What are the features for Genera Spirillum? Give an example of a species under this genus.

Answer 24

Betaproteobacteira
-Chemoautotrophs and chemoheterotrophs. ALL are AEROBIC
Genera Spirillum:
-Relatively Large cell bodies that twist like a Spiral
-habitat is fresh water (except for one species)
-Motile due to bipolar tufts of flagella
ex: Spirillum volutans
(largest spirillum species; 60 um in length)

Question 25

What occurs in the genera for Thiobacillus? What different forms of this genera are there? What important cycle is it important for?

Answer 25

Betaproteobacteria (class)
-Thiobaciluus (acidi-, Halo- and Thermi- ) (beta and gamma)
-Oxidized reduced sulfur for energy and fix Co2 (obligate anaerobes)
-Convert hydrogen sulfide (H2S) or elemental sulfure ito sulfates (SO4^2-)
-Important in the Sulfur cycle

Question 26

Describe what occurs in the Sulfur cycle.REVIEW

Answer 26

Sulfur Cycle:
process:
1. Burining of fossil fuels leads to production of SO2.
2. SO2 will be released and react with air to produce H2 SO3
3. microbial oxidation will also occur and SO2-^4 will be reduced to H2S through decomposition by microbes (dissimilatory)
- H2S will then be converted to elemental oxygen (S^0)
elemental oxygen can be converted back to organic sulfur and animals can consume this organic sulfur through their food
-purple and green phototropic bacteria that gets energy from light (that is found in water) and will have source of electrons to make NADPH and fix CO2

Question 27

Which genera under class Betaproteobacteria include pathogenic species?

Answer 27

Genera:
Burkholderia, Bordetella and Neisseria

Question 28

Describe the characteristics for genera Burkholderia, including its shape. Also include examples of species for this genus.

Answer 28

Betaproteobacteria (class)
Burkholderia :
reclassified from Pseudomonas
*rod-shaped bacteria found in soil
*single polar flagella or tuft of flagella
- B. cepacia: (“cepia” is latin for ONION)
-First discovered as the cause of onion skin rot, then as human pathogen
-Problematic contaminant of hospital equipment and drugs (can degrade >100 different organic molecules and able to grown in disinfectant solutions)
-Opportunistic pathogen that infects the respiratory tract of Cystic fibrosis patients (metabolizes respiratory secretions)
- B. pseudomallei: *the cause of Severe disease (melioidosis)that is endemic in SE (south eastern) Asia and N. Australia

Question 29

Describe the genera Bordetella nad Niesseira? What are their unique features. What are examples of species seen in each genera?

Answer 29

Betaproteobacteria (class)
Genera that include Pathogenic species
- Bordetella:
- B. pertussis
- nonmotile rods/coccobailli
-adhere to cilia of bronchial epithelium
-causative agent of pertussis/WHOOPING COUGH/100 day-cough
-Neisseria
-diplococci
-Use fimbriae to attach to mucous membranes in mammals
N. meningitides: meningococcal meningitis
N. gonorrhoeae: gonorrhoeae.

Question 30

Describe the characteristics for class Gammaproteobacteria. What orders of organisms will be covered under this class?

Answer 30

Gammproteobacteria (class) characteristics:
-The LARGEST Subgroup of Proteobacteria
-Encompass a wide variety of physiological types that live in diverse environments: soil, water, mammalian hosts
Orders covered:
-Thiotrichales
-Pseudomonadales
-Vibrionales
-Enterobacteriales
-Pasteurellales

Question 31

which bacterium can be found under the order Thiotrichales? What are the characteristics of this bacteria? How does this massive bacterium circumvent bacterial size limitations ?

Answer 31

Order Thiotrichales
-Thiomargarita namibiensis (“sulfur pearl of Nambia”)
-Largest known bacterium (100-300 um in diameter)
-Found in seafloor sediments of coastal waters off Namibia
-An interior membrane-bound vacuole filled with nitrate, occupies 98% of cell volume
-Oxidizes H2S and used the stored nitrate as an Anaerobic electron acceptor.
-Elemental sulfur accumulates in the cell when H2S is oxidized
How does massive bacterium circumvent bacterial size limitations?
A surface to cytoplasm ratios is Not that big? (REVIEW this question)

Question 32

How does the bacterium Thiomargarita namibiensis get its pearly appearance? How can this bacterium be visible?

Answer 32

Sulfur granules scatter incident light, lending the cell the pearly lustre.
Thiomargarita namibiensis is visible without additional magnification

Question 33

Describe the important genera that are under the Order Pseudomonadales

Answer 33

Gammaproteobacteria (class)
Order Pseudomonadales has genera:
Pseudomonas, Acinetobacter, Moraxella, Azotobacter and Azomonas.

Question 34

Describe the characteristics for genus Pseudomonas (that is under order pseudomonas). Which Genus did some of these species moved to?

Answer 34

Order pseudomonadales:
Pseudomonas (Genus):
- Aerobic rods
-common in soil
-Polar flagella (single or tufts)
-Opportunistic pathogens
*infect urinary tract, burns and wounds in a weakened host
-Many can grow at refrigerator temperatures (food spoilage)
-Have a large genetic capacity (= yeast) for expression of numerous enzymes to catabolize a wide variety of substrates
(beneficial for decomposing uncommon chemicals present in the soil but problematic in hospitals)
-generally antibiotic resistant due to several efficient efflux pumps
-many species excrete water soluble pigments
-some species moved to Burkholderia (genus) based on rRNA studies

Question 35

What are the characteristics that are under the genus for Acinetobacter ? What order is it under? Give an example of a species for this genus and its characteristics. What are some concerns for this species ?

Answer 35

Other Pseudomonadales (Order) genera;
Acinetobacter (genus); “nonmotile rod”
-aerobic rods, found naturally in soil and water
A. baumanii (species)
*Opportunisitic pathogen found in hospital settings that is primarily a respiratory pathogen, but also infects skin, soft tissues and wounds
*garnered media attention due to an outbreak among wounded soldiers in Iraq and Afghanistan that contracted it during the evacuation chain
Concerns:
-rapidly becomes resistant to antibiotics such that some strains are resistant to most available antibiotics
-Difficult to Eliminate once established in the hospital because it survives on dry surfaces for weeks and is resistant to varies of disinfectants

Question 36

What are features of the genus Moraxella? what is an example of a species and what are its characteristics. How does it affect humans?

Answer 36

Gammaproteobacteria (class)
Other important Pseudomondales genera:
Moraxella
-aerobic coccobacilli
M. lacunata (species) :
* One of several bacteria (and viruses) that can cause conjunctivitis (pink eye): inflammation of the outermost layer of the eye and the inner surface of the eyelids *

Question 37

What are the characteristics for genera Azotobacter and Azomonas? What order do they fall under?

Answer 37

Other imprint Pseudomonales (order) genera:
Azotobacter (“nitrogen fixation”) and Azomonas (monas= unicellular organism)
Azomonas: Large ovoid heavily capsulated bacteria
Azobacter: Free living soil bacteria that fix nitrogen (obtain energy from organic sources in soil)

Question 38

How many families are aerobic in Order legionellales? Discuss the features for genus Legionella include an example of species, the disease and how it is transmitted. What happens with Legionella in amoeba?

Answer 38

Order Legionellales (contains 2 aerobic families )
Legionella (genus)
-found in streams, warm-water pipes, HVAC cooling towers
*Facultative intracellular parasites found in the environment either free-living or within aquatic amoeba
- The amoeba shelter Legionella, protecting them from chemical disinfectants, drying ad heat
-Humans are accidental hosts by inhalation of water droplets containing free-living Legionella, which are engulfed by pulmonary macrophages.
-They prevent phage-lysosomal fusion, and multiply
*L. pnuemophilia
-Legionnaires Disease (pneuomia) (first identified during 1976 outbreak) (29 of 82 died)

Question 39

What are the characteristics for genus coxiella? Give an example of the species and its features.

Answer 39

Gammaproteobacteria (Class)
Order Legnionellales
Coxiella (genus)
C. burnetti
-Originally grouped with rickettsia (obligate intracellular parasites) but NOT transmitted among humans by insect or tick bites
-Wild and domestic animals are reservoirs for the rod-shaped organism. Highly infectious, transmitted to humans via INHALATION of animal derived (urine, feces, etc) dusts, aerosols, or contaminated milk
-Causes flu-like pneumonia called Q fever (named Q for query when causative-agent was unknown)
-highly resistant to environmental stresses such as heat and drying; perhaps due to an endospore-like body in the cell

Question 40

What are the characteristics for the genus Vibrio? What are common species that are seen and their features. What Order does this genus fall under?

Answer 40

Order Vibrionales
Vibrio (genus)
-Facultatively Anaerobic curved rods that are mostly found in aquatic environments
-Vibrio cholera
-found in water/foods contaminated with feces from a person infected with V. cholerae
-causes cholera, characterized by profuse watery diarrhea
V. parahaemolyticus
*gastroenteritis from eating raw or undercooked shellfish

Question 41

How many families are in the Order Enterobacteriales? what are the characteristics of the organism that are under this family Enterobacteriaceae

Answer 41

Order Enterobacteriales
(SEVEN families in 2021)
Family: Enterobacteriaceae
-also called enterics (inhabit intestinal tracts of humans and mammals)
-facultatively anaerobic rods
-Most ferment glucose and other sugars
-if motile, have peritrichous flagella
-Fimbriae to aid with adhesion
-sex pili for exchange of genetic material- frequently confer antibiotic resistance

Question 42

Describe the characteristics for E. coli and what genus and order if falls under. What class does it come from?

Answer 42

Gammaproteobacteria (Class)
Order Enterobacteriales
Escherichia (genus)
E. coli
*common inhabitant of human intestinal tract but NOT most abundant (0.1% of gut flora)
*a great deal is known about its biochemistry and genetics
usually NOT pathogenic, but can cause urinary infections and certain strains produce Shiga toxin or ENTEROTOXINS that cause traveler’s diarrhea or food borne disease
* its presence in food or water, indicates fecal contamination
(the exotoxin acts on intestinal wall)

Question 43

Describe features among the genus salmonella. What family is it under? Class?

Answer 43

Gammaproteobacteria
Order Enterobacteriales
Family: Enterobacteriaceae
Salmonella (genus)
-ALL members are potentially pathogenic
-common inhabitants of many animals, especially poultry and cattle
-can contaminate food under unsanitary conditions

Question 44

Describe the nomenclature of genus Salmonella. Which species are recognized? Describe the serovars that the species are arranged to? Which salmonella species causes typhoid fever?

Answer 44

Nomenclature of genus Salmonella
(changed and restructured several times)
-Only Two species recognized
*Salmonella enterica
*Salmonella bongori (“cold blooded” animal resident)
-These 2 strains are sub classified into 2,400 serovars
-Most of these serovars (1,521) belong to Salmonella enteric and cause more than 99% of the diseases in humans
*Salmonella enterica serovar Typhimirium” is generally written as you would a species, S. typhimirium
*S. typhoid causes typhoid fever (A less severe gastrointestinal disease, Salmonellosis is caused by other Salmonella)

Question 45

Describe the Kauffmann-White Salmonella Serovar Reporting scheme? What defines this scheme. What are antigenic formulas used for? Describe how the Salmonella enterica serotype Typhimurium would be named ?

Answer 45

Kauffamn-White Salmonella Serovar Reporting Scheme:
Defined by the antigenic expression, O and H that relate to variant lipopolysaccharides and flagellin, respectively
Within chart you have serovar type, O antigens, Phase 1 H antigen and Phase 2 H antigens
-Antigenic formulas are used for Unamed Salmonella serotypes
format:
-Salmonella (species) serotype (O antigen): (H1 antigen) : (H2 antigen)
ex: Salmonella enterica serotype Typhimurium= Salmonella enterica serotype 1, 4, 5, 12: i: 1, 2

Question 46

Describe the phase variation of Salmonella Typhimurium flagella

Answer 46

Salmonella change between H1 and H2. (you are switching the flagella protein )
REVIEW slide 44

Question 47

Describe the features for the genera Shigella and Klebsiella. Give an example of species for each genus. What Order do they fall under? Family? Class?

Answer 47

Gammaproteobacteria (Class)
Order Enterobacteriales
Family: Enterobacteriaceae (gram negative)
-Shigella
-all 4 species are responsible for shigellosis/bacillary dysentery
-The most extreme S. dysenterie, causes deadly epidemics, but is Least common species in U.S
-only found inhumane (No other natural animal reservoirs have been proven)
-Klebsiella (genus)
-common in soil and water
-many isolates can fix nitrogen
-K. pneumoniae can cause a serious form of pneumonia

Question 48

What are the characteristics for genus Proteus> What class, Order and Family is it under? Differentiate between swarmer cells and swimming cells? How does a swimmer cell chain to a swarmer?

Answer 48

Gammaproteobacteria (Class)
Order Enterobacteriales
Family: Enterobacteriaceae
Proteus
Opportunistic pathogens if they enter the urinary tract or wound.
Unique multicellular behavior: A proteus colony on Agar exhibits a distinctive series of concentric rings due to swarming growth
1) On the edge of the colony, “swarmer cells with many flagella move outward
2) They then revert to normal, less motile cells, with few flagella, “swimming” state
3) New generations of swarmer cells periodically develop, and the process if repeated
(Example of species: Proteus mirabillis)
A swimmer cells changes to a swarmer: due to a 20-40 fold Increase in cell length and flagella number

Question 49

Compare and contrast swimmer and swarmer in proteus genus

Answer 49

Proteus (genus)
swimmer: shorter cell length and small amount flagella (4-10)
swarmer: have longer cell length (>10 um long) and greater amount of flagella (500-5000)
swarming colony on agar plate can form concentric rings

Question 50

Describe the features of the genus Enterobacter. Which species cause disease. How? What Order and Family is it part of? Class?

Answer 50

Gammaproteobacteria (Class)
Order Enterobacteriales
Family: Enterobacteriaceae
Enterobacter(genus)
-Two species are known to cause disease. E. cloacae and E. aerogenes
*Their presence in the intestinal tracts of animals results in their wide distribution in soil, water, and sewage
*Both can cause urinary and hospital acquired infections

Question 51

Describe the characteristics for genus Yersinia, specifically discussing the species y. pestis. What family and Order are they under?

Answer 51

Gammaproteobacteria (class)
Order Enterobacteriales
Family; Yersiniaceae
Yersina (genus)
Y. pestis causes plague (Black Death of medieval Europe)
( In an 5 year span in 1300’s, 35% of Europe’s population was killed)
*Urban rates in some parts of the world and squirrels and prairie dogs in Southwest U.S carry the bacteria
*fleas bites generally transmit bacteria from animals to humans
*Inhalations of respiratory droplets from infected animals or people can lead to infection

Question 52

Discuss the reported cases of Human Plaque in U.S from 1970-2017

Answer 52

There was an average of 7 cases of Human plague per year

(miscellaneous info 1 dot placed randomly in mostly likely county of exposures for each confirmed plaque case. )

Question 53

Describe the features of genus Serratia, specifically discuss the species S.marcescens. What family and order does it fall under>

Answer 53

Gammaproteobacteria (Class)
Order Enterobacteriales
Family: Yersiniaceae
Serratia (genus)
S. marcescens is distinguished by production a RED PIGMENT
*intially considered completely harmless, now recognized as an opportunistic pathogen found to cause many hospital acquired urinary, respiratory and wound infections. Likely because it is found in solutions in hospitals that should be sterile (ex, catheters, saline solutions)

Question 54

Describe the characteristics of genus pasteurella, including the species P. multocida and its features. What Order and Class is it under? Describe the virulent strain of this species found in an axial that can kill in days.

Answer 54

Gammaproteonbacteria (Class)
Order: Pasteurellales
-Pasteurella (Genus)
-primarily pathogens of domestic animals
Best known species is P. multocida , which can be transmitted to humans via dog and cat bites. It presents as an infection that complicated the animal bite or injury
-An especially virulent strain is present in Komodo dragon saliva and is introduced into its more mobile prey by a bite (kills in several days)

Question 55

Describe the features of the genus Haemophilus? What Class and Order is it under?
What are features for the species H. influenza and H. ducreyi?

Answer 55

Gammaproteobacteria
Order pasteurellales
Haemophilus (genus)
-pathogens that inhabit the mouth, upper respiratory tract, intestinal tract and vagina
-named for their blood requirement in culture media
(hemo= blood) (philus= liking)
*Their requirements for X (heme from hemoglobin) and V (NAD+ or NADP+) factors can be used to differentiate species
H. influenzae
-mistakenly considered to be the cause of influenza until 1933
-Causative agent of meningitis, earaches, bronchitis, pneumonia and septic arthritis
H. ducreyi
-causes the sexually transmitted disease chancroid (causes genital ulcers)

(H influenza growth only around disc impregnated with BOTH X and V factors)

Question 56

Describe the different genera for Deltaproteobacteria Class and how to distinguish them

Answer 56

Deltaproteobacteria (class);
Anaerobic: OR Aerobic:
Desulfovibrio Predator—> bdellovibrio
Gliding—> Mycococcus

Question 57

Discuss the features of genus Bdellovibrio. Further discuss how it is able to attack and destroy host cell. Give an example of species that does this.

Answer 57

Deltaporoteobacteria (class)
-Genus Bdellovibrio
-bdella= leech
attaches tightly to other gram-negative bacteria (like E. coli) penetrates the outer layer and enters the periplasm.
-it breaks down the host cell molecules, which it uses to elongate and form a filament
-Filament fragments into several individual flagellated cells that are released by cell lysis
ex: B. bacteriovirus attacks a bacteria cell

Question 58

Would a bacterium like B. bacteriovirus attack Staphylococcus aureus ?

Answer 58

No since bdellovibrio does not attack gram-positive bacteria ? (staphylococcus aureus is gram-positive)
REVIEW THIS ANSWER (Slide 57)

Question 59

Describe the features of Desulfovibrionales. what class do they fall under? What is the best studied genus?

Answer 59

Deltaproteobacteria (class)
-Members of the Order Desulfovibrioniales are…
-Sulfur reducing bacteria that play a key role in the sulfur cycle
-Use oxidized S (ex> S^0, SO4^2-) instead of O2 as final electron acceptor and produce reduced H2S
-Desulfovibrio (Best studied genus)
*obligate anaerobes found in sediments and intestinal tracts of humans and animals
*use organic compounds such as lactate, ethanol or fatty acids as electron donors
*black color of many sediments/sludge is due to H2S reacting with Iron to form insoluble FeS.

Question 60

What are the characteristics for order Myxococcales? What Class is it under? what does Myxococcales mean? describe the features of the genus and explain what cooperative predation is ?

Answer 60

Deltaproteobacteria (class)
Order Myxococcales
-illustrate the most Complex life cycle of bacteria (part predatory upon other bacteria)
- Myxococcus
*myxo= nasal mucus
*vegetative cells move by gliding motility and leave a slime trail , obtain nutrient from bacteria they encounter and enzymatically lyse
*cooperative predation is accomplished by secretion antibiotics and lytic compounds that immobilize and degrade prey organisms, thereby creating a public pool f nutrients

Question 61

What is an example of species under Order Myxococcus?

Answer 61

Myxococcus xanthin preying on an E. coli colony
(7 days real time)

Question 62

Discuss the life cycle of Order Myxcoccoales? What are the steps of this process?

Answer 62

Life cycle of Order Myxococcales:
1. Myxospores are resistant resting cells released from sporangiospores upon favorable conditions
2. Germination: myxosproes germinate and form gram-Negative vegetative cells, which divide to reproduce
3. Vegetative growth cycle: vegetative myxobacteria are motile by gliding, forming visible slime trails
4. Aggregation: under Low nutrient conditions, the vegetative cells swarm to central locations by quorum sensing, forming an aggregation
5Mounding: Aggregations of cells heap up into the mound, an early fruiting body
6. Mounds of mycobacteria differentiate into mature fruiting body, which produces myxospores packed within sporiangoles (about 100,000 cells)

Question 63

What are the characteristics of the Class Epsilonproteobacteria? What are the features for the genera campylobacter and Helicobacter. Give a species for each genera and discuss features.

Answer 63

Epsilonproteobacteria (Class)
-Slender rods that are helical or curved. Two medically important genera. Both are microaerophilic and motile by means of flagella
Campylobacter (genus)
-SINGLE polar flagella
-C. jejune is leading cause of foodborne gastroenteritis
-C. fetus causes spontaneous abortion in domestic animals
Helicobacter
-MULTIPLE flagella
-H. pylori can infect the lining of the stomach. Most common cause of peptic ulcers (not thought to have a microbial cause prior to 1982) and associated with the development stomach cancers

Question 64

What is the difference between proteobacteria and Nonproteobacteria?

Answer 64

Proteobacteria: contains all gram-NEGATIVE bacteria
Nonproteobacteria: contains Both gram-negative and gram-positive bacteria

Question 65

Which phyla under Nonproteobacteria are gram negative? Which phyla are gram positive ?

Answer 65

Nonproteobacteria
Gram-Negative Phyla: Cyanobacteria, Planctomycetes, Chlamydiae, Spirochetes, Bacteroides, Fusobacteria, Deinoccoccu thermius (review),
Gram Positive Phyla: Firmicutes, Tenericutes, Actinobacteria

Question 66

Under Nonproteobacteria, gram-negative, discuss the characteristics of Phylum cyanobacteria? Explain how they are morphologically varied. What are Heterocysts?

Answer 66

Nonproteobacteria Gram-negative bacteria
Phylum Cyanobacteria
-Oxygenic Photosynthesis (chlorophyll a, like algae and plants)
-Named for characteristic blue-green (cyan) pigmentation and once called “blue green algae”—They are NOT eukaryotic algae
-believed to have generated most of the Earth’s atmospheric O2 millions of years ago (0.1%–> 10% when plants arrive)
Morphologically varied:
Unicellular: divide by binary fission
-Colonial: Multiple fission (parent divides multiple times by mitosis, producing several nucleotides; Cytoplasm then separates creating multiple daughter cells at once)
-Filamentous: fragmentation
-Many filamentous cyanobacteria fix nitrogen in specialized cells called Heterocysts

(filamentous cyanobacteria can have heterocyst)
(unicellular non filamentous cyanobacterium) held together by mucopolysaccharides)

Question 67

What are the characteristics for Anoxygenic Photosynthetic Bacteria? What group of organisms does it fall under. Explain why these organisms can be taxonomically confusing and provide phylums for each type of bacteria.

Answer 67

Nonproteobacteria, Gram Negative Bacteria
Anoxygenic Photosynthetic Bacteria
-Are generally anaerobic
-grow at great aquatic depths and use bacteriochlorophyll (utilizes a portion of the light spectrum NOT intercepted by organisms at higher levels)
-morphollogically diverse (spiral, rods, cocci and budding forms)
*Taxonomically confusing
*Green non sulfur bacteria- Phylum Chloroflexi
*Green Sulfur bacteria- phylum Chlorobi
*Purple non sulfur bacteria - Phylum Proteobacteria (gamma)
*Purple Sulfur bacteria -Phylum Proteobacteria (alpha)
-Not necessarily colored green or purple
*purple bacteria have various carotenoids, which give them colors raging between purple, red, brown, and orange
*Most green sulfur bacteria are green but some have a brown tint

Question 68

Describe the two major photographic reactions and include their equations and examples of bacteria that use these reactions
What is a characteristic for Purple/green non sulfur bacteria?

Answer 68

Phototrophic reactions:
-Oxygenic photosynthesis
Cyanobacteria:
2 H2O + CO2 , use light ——-> (CH2O) + H2O + O2

-Anoygenic Photosynthesis
Purple green Sulfur bacteria:
2 H2S + CO2 use light——-> (CH2O) + H2O + 2 S^0

Purple/Green NON-Sulfur bacteria: photoheterotrophs that use organic compounds (acids and carbohydrates) for their sources of carbon

Question 69

Describe the features for Phylum Planctomycetes. What group does this fall under? What are the features for the Genera Planctomyces and include characteristics of species Gemmata obscuriglobus

Answer 69

Nonproteobacteria, Gram Negative bacteria
Phylum Planctomycetes
-May blur the definition of bacteria
-Bacterial rRNA gene sequence
-Members displayed number of unusual properties
Genus Planctomyces
-Aquatic budding bacteria that produce Stalks like Caulobacter
-initially thought to lack peptidoglycan cell walls, but later disproved
Gemmata obscuriglobus
-may be a model for the origin of the eukaryotic nucleus
-Double internal membrane around DNA, like a nuclear membrane
(newer findings challenge the idea of eukaryotic ancestry of the phylum)
(planctomyces have buds at Endosymbiotic of hypha, holdfasts and stalks)

Question 70

What are the features of the phylum Chlamydiae ? what are the two genera that will be discussed?

Answer 70

Nonproteobacteria, Gram Negative Bacteria
Phylum Chlamydiae
Remarkably diverse phylum, but our discussion will be limited to only two genera: chlamydia and Chlamydophila
*Obligate intracellular parasites
*Direct Transmission: interpersonal contact or aerosols (not by ticks, etc)
-Lab cultivation is difficult; must be cultivated in lab animals, cell culture or yolk sac of embryonate chicken eggs

Question 71

Describe the medically important species for the genera Chlamydia and chlamydophila. What diseases can be produced?

Answer 71

Medically important species:
Chlamydia trachomatis; Different Servers are responsible for different diseases:
1) Trachoma (leading cause of blindness in developing countries)
Sexually transmitted diseases
2) nongonococcal urethritis (most coming BACTERIAL STD in U.S
3) lymphogranuloma centrum

Chalymdophila pneumoniae
-mild form of pneumonia
Chlamydophila psittaci
Respiratory disease
psittacosis
(infection caused by psittaci that is transmitted from infected bird to humans)

Question 72

Discuss the Life cycle of Chlamydias (chlamydia and Chalmydophila)

Answer 72

Life Cycle of the chlamydias (Chlaymydia and Chlamydophila)
1. The bacterium’s infectious form, the elementary body attaches to a host cell(contains nucleus)
2. The host cell phagocytizes the elementary body, housing it in a vacuole
3. The elementary body reorganizes to form a Reticulate form (REPLICATING form)
4. The reticulate body divides successively, producing multiple reticulate bodies
5. The reticulate bodies begin to convert back into elementary bodies
6. The elementary bodes are released form the host cell.
Elementary body (NON-REPLICATING with rigid outer membrane)

Question 73

Distinguish between the elementary body and the reticulate body ?

Answer 73

Elementary body: NON-replicating with rigid outer membrane
reticulate body (Replicating form)

Question 74

How many hours does it take to complete life cycle for chlamydias? What are the two developmental stages for Chlamydia ? How does chlamydia induce phagocytosis ?

Answer 74

Life cycle of Chlamydias, takes about 48 hours to complete
Chlamydia has two developmental stages- the elementary body (EB) and the reticulate body (RB)
Chlamydias induces its own phagocytosis via contact with host epithelial and endothelial cells.

Question 75

Discuss the characteristics of the Phylum Spirochaetes. Also discuss which group of bacteria they are apart of? Discuss features of genera/ species Borrelia burgdorferi, Leptospira (genera), and Treponema pallidum

Answer 75

Nonproteobacteria, Gram Negative Bacteria
Phylum Spirochaetes
-Name is derived from their coiled morphology
-Motile bacteria (rotating axial filaments)
-Many inhabit the human oral and vaginal cavities
Most important pathogenic genera/species:
-Borrelia burgdorferi: causavtive agent of LYME DISEASE; transmission from ticks or lice to humans
-Leptospira: Lesptospirosis, transmission from animals to humans through contaminated water.
-Treponema pallidum: causative agent of SYPHILLIS

Question 76

What are the features for Spirochetes? what kind of bacteria are they and what is their role? What does the structure look like?

Answer 76

Spirochetes
-Motile bacteria: utilized two or more axial filaments (endoflagella)
-Allows the cell to to rotate like a corkscrew, easily cutting thought liquids

Question 77

What are the features for Spirochetes? what kind of bacteria are they and what is their role? What does the structure look like?

Answer 77

Spirochetes
-Motile bacteria: utilized two or more axial filaments (endoflagella)
-Allows the cell to to rotate like a corkscrew, easily cutting thought liquids

Question 78

What are the features for Spirochetes? what kind of bacteria are they and what is their role? What does the structure look like?

Answer 78

Spirochetes
-Motile bacteria: utilized two or more axial filaments (endoflagella)
-Allows the cell to to rotate like a corkscrew, easily cutting thought liquids

Question 79

What are the features for Spirochetes? what kind of bacteria are they and what is their role? What does the structure look like?

Answer 79

Spirochetes
-Motile bacteria: utilized two or more axial filaments (endoflagella)
-Allows the cell to to rotate like a corkscrew, easily cutting thought liquids.
Structure: cell with Axial filaments, sheath

Question 80

Describe the phylum Bacteroides and the type of bacteria it has in several genera. What are the characteristics for genera Bactericides?

Answer 80

Nonproteobacteria, Gram Negative Bacteria
Phylum Bacteroides
-includes several genera of ANAEROBIC bacteria
Genus Bacteroides
-Rod-shaped, non-motile, non-endospore forming bacteria
-Common inhabitants of the GI tract (predominant protein/30%)
-Some species found in gingival crevice (between teeth and gums)
-Cause infections at surgical sites, puncture wounds and through perforated bowel

Question 81

Describe the characteristics for the Phylum Fusobacteria. What group of bacteria does it belong to?
What are the features of Genus Fusobacterium?

Answer 81

Nonproteobacteria, Gram Negative Bacteria
Phylum Fusobacteria
-Anaerobic phylum
-Often pleomorphic but may be spindle-shaped (fuso= spindle)
Genus Fusobacterium:
-Long, slender spindle-shaped rods with pointed ends
-Primarily found in the mouth where it may be involved in dental diseases
-Also identified as a pathogen in other parts of the body.

Question 82

What are features of the Phylum Deinoccocus-Thermus?
Describe the features for species Deinococcus radiodurans and Thermus aquaticus? What does Thermus aquaticus provide?

Answer 82

Phylum Deioncoccus-Thermus
Although, they have a Thick cell wall that allows them to stain gram-positive, they also have an outer membrane, and so are closer in structure to GRAM-NEGATIVE cells
*Deinococcus radiodurans
- More resistant to radiation that endospores (survive a radiation exposure 1500x the dosage that would kill a human)
-Resistance is due to rapid repair of radiation damage, which also extends to chemical mutagens (change in DNA)
*Thermus aquaticus
-Isolated from a Hot spring in Yellowstone National Park
-Source of TAQ POLYMERASE

Question 83

Describe how bacteria are Gram-positive are divided? Discuss the differences within the gram-positive phylum (Firmicutes, Actinobacteria and Tenericutes)

Answer 83

Gram positive bacteria can be divided based on the G/C content of their genetic material
(G/C–> guanine/cytosine)
-Phylum Firmicutes: LOW G/C content
-Phylum Tenericutes: LOW G/C content
Phylum Actinobacteria: HIGH G/C content

Question 84

Illustrate the dichotomous key for Firmicutes that is used to distinguish the different species. What are the features in common? What is the Dichotomous key based on?

Answer 84

Dichotomous key for Firmicutes
-Low G + C
-Gram- positive
Low G + C gram-positives:
Tenericutes is placed into their own phylum
Have cell walls:
Produce endospores OR. NO endospores
= Anaerobic OR Aerobic = Lactobacillale
=Clostridiales & Fac Anaerobic –> Bacillales*
This Dichotomous key is based on ORDERS

Question 85

What are the characteristics for the genus Clostridium. What Order and Family is it under. What are the 4 main species and their features?

Answer 85

Firmicutes (phylum)
Order: Clostridiales
Clostridium (genus) Characteristics:
-Common in soil
-form endospores
-obligate anaerobes
-rod shaped, often distended due to presence of endospores
4 pathogens:
C. difficile: GI tract infections
C. botulinum: food poisoning
C. tetani: tetanus
C. perfringens: foodborne diarrhea

Question 86

What are the features for genus Epulopiscium? What Order and Phylum is it under?

Answer 86

Firmicutes (Phylum)
Order: Clostridiales
Epulopiscium (guest at the banquet of a fish)
-Nutritionally symbiotic in the digestive tract of surgeon fish (Tang)
-Considered too LARGE to be a bacterium (visible by naked eye) and seems to break the known rules of size/diffusion limitation
*its cell walls contains many folds that increase surface area and the organism is literally bathed In undigested food
*Does NOT rely on diffusion to distribute nutrients because it synthesizes macromolecules where needed
-Initially classified as a protozoan, reclassified as a bacterial based upon:
*Lack of membrane enclosed nucleus
*Analysis of rRNA

Question 87

compare the size of Epuplopiscium and E. coli Which is bigger? Which has larger volume?

Answer 87

E. coli (1 um x 2 um)
Epulopiscium (89 um x 600 um)
Epulopiscium is LARGER
1 million times larger volume

Question 88

Explain how the Epuplopiscium replicates? How many cells are released? How many copies of its genome does it have?

Answer 88

Replication:
Epulopisicum daughter cells grow within the mother cell until they fit the cell and burst the cell wall
once offspring development is complete, the mother cell dies and releases offspring
-1 to 7 cells are released
-contains tens of thousands of copies of its genome, which may help it to overcome diffusion constraints

Question 89

Describe the characteristics for Genus Bacillus? What Order and Phylum is it under?
What are the features for species Bacillus anthracis, Bacillus thuringiensis and Bacillus cereus?

Answer 89

Firmicutes (Phylum)
Order: Bacillales
Bacillus (genus)
-Endospore-forming rods
Obligate aerobes or facultative Anaerobes
-common in soil and often forms chains in culture
-several species produce antibiotics
-only a few pathogenic to humans
*Bacillus anthracis:
-disease of cattle, sheep and horses that can be transmitted to humans (linked with bioterrorism)
*Bacillus thuringiensis:
-agriculturally important insect pathogen used as a pesticide
*Bacillus cereus: associated with food poising, typically through infection of starchy foods (ex: rice)
*These 3 species are considered variants of the Same species differing only by VIRULENCE genes carried on plasmids easily transferred to one another

Question 90

Describe the characteristics for the Genus Staphylococcus? What Order and Phylum is it under? Discuss the specific features for species Staphylococcus aureus

Answer 90

Firmicutes (Phylum)
Order: Bacillales
Staphylococcus:
-Cocci bacteria that typically arrange themselves in grape-like clusters
-considered part of our normal flora
-Grow well in high osmotic pressure, low moisture conditions (nasal passages and on skin)
Staphylococcus aureus:
-GOLDEN in color ( may protect form antimicrobial effects of sunlight)
-Produce many exotoxins to aid its pathogenicity (allow invasion or damage tissues)
-Commonly infect surgical wounds
-Develop drug resistance quickly
-Infections differ by anatomic region:
-Vaginal tract: toxic shock syndrome
-GI tract: food poisoning
-Respiratory tract: sinus infections

Question 91

What are the characteristics for the Genus Lactobacillus? What order and Phylum is it under? Explain the significance of most species under this genus lacking an electron transport chain

Answer 91

Firmicutes (phylum)
Order: Lactobacillales
Lactobacillus (species)
-Commerically important in pickle, yogurt, sauerkraut, and buttermilk production
-Generally aerotolerant anaerobes (they use fermentation to produce energy (ATP)
-In humans, can be found in oral cavity, vaginal and GI tracts
-Most lack an electron-transport chain
What does this mean: Inefficient metabolism; can NOT utilize oxygen as electron acceptor. They grow poorly compared to oxygen utilizing bacteria
-however, since they generate lactic acid from simple carbohydrates—- the Low pH inhibits the growth of competing organisms

Question 92

What are the characteristics for the Genus Streptococcus? What Phylum and Order is it under?

Answer 92

Firmicutes (phylum)
Order: Lactobacillales
Streptococcus (genus)
-Cocci bacteria that typically grow in chains
*responsible for more illnesses and Greater variety of diseases than any other genus
-Express and secrete substances that aid in its pathogenicity
-Proteins to kill phagocytic cells
-Enzymes that help spread infection:
-digest host connective tissues which may also cause tissue destruction
-destroy fibrin, a component of blood clot

Question 93

How can the Streptococci be classified? Differentiate between species that are Alpha, beta, and gamma hemolytic and features that make them unique. Out of the hemolytic groups, which contains most virulent streptococci?

Answer 93

Streptococci can be classified based upon their Colony Appearance on blood agar medium
-Alpha-hemolytic species partially degrade red blood cells (due to hydrogen peroxide production) and their colonies are surrounded by a distinctive Greening
-Beta-hemolytic species express hemolysin that lyses red blood cells, leaving a CLEAR Zone around the colony (yellow color) .
S. pyogenes (Beta-hemolytic group A strep): causative agent of Scarlet and Rheumatic Fever
- S. agalactiae (beta-hemolytic Group B Strep): neonatal sepsis
-Gamma-hemolytic species DO NOT Affect red blood cells and are usually NOT pathogenic
(hence red, regular blood agar color)
-** The Beta group contains the most Virulent Streptococci and is divided into Lancefield antigenic groups (A-G) based on Streptococci cell wall carbohydrate antigens.

Question 94

What is the significance of viridans streptococcus?
How colonies on blood agar plate for beta, alpha and gamma hemolytic species appear?

Answer 94

viridians streptococcus is a common name for a large group of normal microbiota streptococcal bacteria that are either alpha-hemolytic (“viridian’s means green, hence the name) or nonhemolytic
(on Beta hemolysis plate, appearance on blood agar play is yellow; on alpha hemolysis plate: appearance is green; on gamma hemolytic (RBCS not affected) , so not pathogenic (color is red)

Question 95

Describe the characteristics for Genus Enterococcus. What phylum and order is it under. Discuss the species that cause infections

Answer 95

Firmicutes (phylum)
Order: Lactobacillales
Enterococcus (Genus)
-Part of our normal intestinal flora that occasionally cause urinary tract infections and sepsis
-Adapted to nutrient rich, low oxygen body regions
-GI tract
-Oral cavity
-Vagina
-major cause of Hospital-acquired infections because they persist on inanimate objects for long periods of time and have high resistance to most antibiotics
-E. faecalis and E. faecium, are responsible for most surgical wound and urinary tract infections

Question 96

What are the characteristics for Genus Listeria? What was it named after? What Order and Phylum is apart of. Describe the Listeria Outbreak that occurred in 2011. Discuss other features of the L. monocytogenes species

Answer 96

Firmicutes (phylum)
Order: Lactobacillus
Listeria (named after Joseph Lister0
-L. monocytogenes is usually the causative agent of listeriosis, a serious infection caused by eating food contaminated with the bacteria
_one of the most Virulent food borne pathogens (20-30%) of clinical infections result in death)
* a 2011 Listerosis Outbreak from contaminated cantaloupe sickened 147 and killed 33.
-facultative intracellular parasite that survives within phagocytic cells and infection of pregnant women
-Capable of growth at refrigeration temperatures

Question 97

Discuss the features of the Genus Mycoplasmas. What Order and Phylum is it under? What makes it so special? Discuss the most significant species and why it is

Answer 97

Phylum Tenericutes
Order: Mycoplasmas
-lack a cell wall; pleomorpic as a result
-Named (“mykes” = fungus and plasma= formed) because they produce filaments resembling those associated with fungi
-Very small (0,1-0.25 um)and originally classified as
viruses
-May be the smallest, self-replicating, free living form
-DNA analysis suggests once closely related to Bacillus, Lactobacillus, and streptococcus but LOST genes over time
-M. pneumonia is the most signicant species, causing mild pneumonia

Question 98

What is the structure of M. pneumoniae and how does this affect its role?

Answer 98

M. pneumonia have arrowheads, which indicate terminal structures that probably aid in attachment to eukaryotic cells, which then become infected.
M. pneumonia also reproduces by fragmentation of the filaments at the bulges.

Question 99

Describe the dichotomous key for Actinobacteria? How are these organisms divided? What is the feature of Actinobacteria?

Answer 99

Actiobacteria (phylum)
phylum name derived from the Greek “actino” meaning “ray”because above genera appear to radiate due to manmber of branching filament
Dichotomous key for Actinobacteria
-All have High G+ C and Gram-POSITIVE:
Form filaments OR. have NO mycelia
No condidospores OR Form Condidospores
Acid-fast OR. Fix N2 Aerobic or Anaerobic
Acid-fast–> Nocardia; Aerobic–>. Streptomyces
Fix N2—> Frankia Anaerobic–> Actinomyces

No mycelia—Acid Fast–> Mycobacterium
No mycelia–> NOT Acid fast–> stain gram+——> Cause diphtheria–> Corynebacterium
Or Not Aci-d Fast–> stain gram + —-> make propionic acid—> Propioinibacterium.

Question 100

Describe the morphology and continent seen in Actinobacteria. What are the features seen in genera Corynebacterium? What are the advatages of organisms with filamentous design?

Answer 100

Actinobacteria; HIGH G/C content
Some are Highly pleomorphic in morphology and others grown old as extend, often branching filaments
-The genera Corynebacterium is pleomorphic
-Filamentous genera resemble fungi but are PROKARYOTES
*some, like fungi also carry external spores for reproduction
*Common soil inhabitants
*Advantages of filamentous design
-organism can bridge a water-free gap to a new nutritional site
-increased surface area for greater nutrient absorption

Question 101

Discuss the characteristics of the Genus Streptomyces> Why is it important? What does the structure look like?

Answer 101

Actinobacteria
-The genus Streptomycetes:
-is one of the most common soil isolates
-Reproductive asexual spores (Condidospores) form at the end of the coiled aerial filaments that can germinate into a new colony if released into proper conditions
-Are strict aerobes
-Produce a gaseous compound, geosmin, that gives soil its musty odor
Valuable because they produce most of our commercial antibiotics

Question 102

What are the characteristics for Genus Mycobacterium? what king of bacteria is it, and how does the cell wall appear. Also discuss important species of Mycobacterium

Answer 102

Actinobacteria
Genus: Mycobacterium (NOT Gram POSITIVE)
-Aerobic, non-spore forming rods
-“Myco” = fungus-like; named because they occasionally exhibit filamentous growth
-Cell wall is similar to gram negative bacteria, But the outermost lippopolysaccharde layer of their cell wall is replaced by mycolic acids, giving them a waxy, watery resistant layer. This results in:
*Acid-fast staining
*Blocked entry of antimicrobial compounds
*resistance to environmental stressors like drying
*Reduced nutrient uptake and growth rate
*Important membrers include M. tuberculosis and M. leprae, causative agents of tuberculosis and leprosy, respectively

Question 103

What are characteristics for the Genera Actinomyces and Nocardia. Give an example of species for each genera and their significance.

Answer 103

Genus Actinomyces:
-Facultative anaerobes, branched filaments that replicate by Fragmentation
- Common in soil and animal microbiota, present in the mouth and throat of humans
-One species, A. Israeli, is the causative agent of actinomycosis, a tissue destroying disease affecting the head, neck, or lungs
Genus Nocardia:
-Morphologically similar to Actinomyces and also replicate by fragmentation
Aerobic, acid-fast bacteria (NOT gram Positive)
-Common in soil
Nocardia asteroids can cause a chronic pulmonary infection and is also the cause of a mycetoma, a localized infection affecting feet and hands.

Question 104

What are the feats for Genera, Corynebacterium Propionibacterium, and Frankia? Provide common species seen for each genus

Answer 104

Actionbacteria
Genus Corynebacterium:
coryne= club-shaped
-pleomorphic, morphology often changes with age
-C. diphtheria ist he causative agent of diphteria
Genus Propionibacterium:
-named for ability to form propionic acid
some species important in the formation of Swiss cheese (forming holes in the chess)
P. acnes are commonly found on human skin and implicated as primary bacterial cause of acne
Genus Frankia:
causes nitrogen-fixing nodules to form on alder tree roots

Question 105

What are the 5 main groups in Domain Archaea? How are they organized? What are eh characteristics?

Answer 105

Domain Archaea
-Placed into 5 groups: (3) physiological and (2) nutritional
Thermophiles: high temperatures: >80 degrees
Acidophiles: survive in extremely low pH (and often high temps)
Halophiles: thrive in high salt concentration
Nitrifying: oxidize ammonia for energy
Methanogens: anaerobic bacteria that generate methane gas by combining CO2 and H2

(nutritional groups are nitrify ing and methanogens)

Question 106

Discuss the microbial diversity that occur. What is used to observe this diversity and what is needed to understand metabolism and ecological role of bacteria ?

Answer 106

Microbial Diversity
-PCR indicates up to 10,000 different types of bacteria in 1 gram of soil
-Many bacteria have NOT been identified because they have NOT been cultured
-Need special nutrients
-Are a part of complex food chains requiring the products of other bacteria
-Culturing is necessary to understand their metabolism and ecological role