Microbial Ecology

Question 1

Medical Applications

Answer 1

1) Infectious disease and pathogenesis - (a)The great plague (bacterium Yersinia pestis)
(b) malaria: Protozoan Plasmodium falciparum
2) Immunology, innate defenses, antibodies, lymphocytes, immune diseases

Question 2

Agriculture application

Answer 2

agrobacterium, biocontrol, pesticide biodegradations

Question 3

Environmental applications

Answer 3

aquatic, soil, biofilms, extremophiles

Question 4

Industrial applications

Answer 4

fermentation, food spoilage, lactic acid bacteria

Question 5

Genetics/Genomic applications

Answer 5

DNA changes, microbial fermentations, gene regulation/therapy, virus vaccines

Question 6

Ecosystem

Answer 6

a community of organisms and their natural environment, energy flow and materials cycling in system

Question 7

Population

Answer 7

group of organisms of the same species in the same place at the same time

Question 8

Guild

Answer 8

metabolically similar populations that exploit the same resources in a similar way

Question 9

Water column community 1

Answer 9

photic zone: Oxygenic phototrophs

6CO2+6H2O->C6H12O6 + 6O2

Question 10

Water column community 2

Answer 10

Oxic zone: Aerobes and facultative aerobes

6CO2+6H2O

Question 11

Bottom Sediment Community 3 (Anoxic sediments): Guild 1

Answer 11

Denitrifying bacteria (NO3- -> N2)
Ferric iron-reducing bacteria (Fe3+ -> Fe2+)

Question 12

Bottom Sediment Community 3 (Anoxic sediments): Guild 2

Answer 12

Sulfate-reducing bacteria (SO4 -2 -> H2S)
Sulfur reducing bacteria (S0 -> H2S)
-sulfinogenics, create sulfides

Question 13

Bottom Sediment Community 3 (Anoxic sediments): Guild 3

Answer 13

Fermentative Bacteria

Question 14

Bottom Sediment Community 3 (Anoxic sediments): Guild 4

Answer 14

Methanogens (CO2->CH4)

Acetogens (CO2-> acetate)

Question 15

Energy Flow

Answer 15

Chemotrophy

• Energy from either organotroph (sugar) (aerobic)or lithotroph (Nh3, H2, S0)(anaerobic), internal electron acceptor is fermentation
• Carbon from organic (heterotroph) or inorganic (autotroph)

Question 16

Chemoorganoheterotrophy

Answer 16

Energy source: Chemicals
Electron source: Organic e- donor
Carbon source: Organic carabon
Microorrganisms: most non-photosynthetic microbes

Question 17

Chemolithoheterotrophy

Answer 17

Energy source: Chemicals
Electron source: Inorganic e- donor
Carbon source: Organic carabon
Microorrganisms: some sulfur-oxidizing bacteria

Question 18

Chemolithoautotrophy

Answer 18

Energy source: Chemicals
Electron source: Inorganic e- donor
Carbon source: CO2
Microorrganisms: some sulfur-oxidizing bacteria, iron-oxidizing bacteria, methanogens, nitrifying bacteria

Question 19

Photolithoautotrophy

Answer 19

Energy source: Light
Electron source: Inorganic e- donor
Carbon source: CO2
Microorrganisms: cyanobacteria, purple and green sulfur bacteria

Question 20

Photoorganoheterotrophy

Answer 20

Energy source: Light
Electron source: organic e- donor
Carbon source: Organic carabon
Microorrganisms: purple and green non-sulfur bacteria

Question 21

Groupings of Phototrophic bacteria

Answer 21

cyanobacteria, Anaerobic anoxygenic (purple non/sulfur, green non/sulfur, heliobacterium), aerobic anoxygenic, oxygenic, prochlorophytes

Question 22

objectives of microbio ecology

Answer 22

biodiversity and measure activities in nature

Question 23

Activities measured in microbio ecology

Answer 23

1) primary production
2) Decomposition
3) biogeochemical cycling of elements

Question 24

Microorganisms in nature

Answer 24

• live in common habitats suited to higher organisms as well as in extreme environements
• need resources and physiochemical conditions for growth

Question 25

Psychrophiles, thermophiles, hyperthermophiles

Answer 25

live in habitats of extreme temps

Question 26

halophilic archaea

Answer 26

red colour due to microbial pigments

Question 27

niche

Answer 27

role of an organism in an ecosystem containing the physical habitat, functional role, and interactions

Question 28

Microenvironment

Answer 28

place where microbes live and metabolize, contain physiochemical gradients - with spatial, temporal variability

Question 29

Nutrient levels and growth rate

Answer 29

1) entry of nutrients into an ecosystem is often intermittent, adapt growth to nutrient levels
2) distribution of resources = non-uniform
3) competition for resources is likely

Question 30

Biofilms

Answer 30

community of microorganisms embedded in matrix of extracellular polymeric substances adhering to the surface

Question 31

advantages to biofilms

Answer 31

-protection, immune system cells, stay in a fav niche, nutrient trapping

Question 32

disadvantages to biofilms

Answer 32

-competitive, localized biomass = easy predation, infection by viruses

Question 33

problems from biofilm formation

Answer 33

-pipe clogging, corrosion, disease

Question 34

exploitation of biofilms

Answer 34

slow filtration, microbial leaching of low grade ores, vinegar production

Question 35

microbial mats

Answer 35

communities of mainly photosynthetic or chemolithotrophic bacteria

Question 36

cyanobacterial mats

Answer 36

population of photosynthetic primary consumers and producers

• green layers: cyanobacterial layers
• orange: layers of anoxygenic phototrophic bacteria

Question 37

Negative effects between interacting microbial populations

Answer 37

-competition and antagonism (specific inhibitor or metabolic product impedes growth/metabolism

Question 38

Positive effects between interacting microbial populations

Answer 38

cooperative interactions

1) syntrophy, work together, one cant function without the other
2) carry complementary metabolic interactions eg. nitrification

Question 39

symbiosis

Answer 39

intimate relationship between two organisms

1) mutualism- both species benefit
2) parasitism- one benefit, other harmed