Microbial Ecology Flashcards
Medical Applications
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
Agriculture application
agrobacterium, biocontrol, pesticide biodegradations
Environmental applications
aquatic, soil, biofilms, extremophiles
Industrial applications
fermentation, food spoilage, lactic acid bacteria
Genetics/Genomic applications
DNA changes, microbial fermentations, gene regulation/therapy, virus vaccines
Ecosystem
a community of organisms and their natural environment, energy flow and materials cycling in system
Population
group of organisms of the same species in the same place at the same time
Guild
metabolically similar populations that exploit the same resources in a similar way
Water column community 1
photic zone: Oxygenic phototrophs
6CO2+6H2O->C6H12O6 + 6O2
Water column community 2
Oxic zone: Aerobes and facultative aerobes
6CO2+6H2O
Bottom Sediment Community 3 (Anoxic sediments): Guild 1
Denitrifying bacteria (NO3- -> N2) Ferric iron-reducing bacteria (Fe3+ -> Fe2+)
Bottom Sediment Community 3 (Anoxic sediments): Guild 2
Sulfate-reducing bacteria (SO4 -2 -> H2S)
Sulfur reducing bacteria (S0 -> H2S)
-sulfinogenics, create sulfides
Bottom Sediment Community 3 (Anoxic sediments): Guild 3
Fermentative Bacteria
Bottom Sediment Community 3 (Anoxic sediments): Guild 4
Methanogens (CO2->CH4)
Acetogens (CO2-> acetate)
Energy Flow
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)
Chemoorganoheterotrophy
Energy source: Chemicals
Electron source: Organic e- donor
Carbon source: Organic carabon
Microorrganisms: most non-photosynthetic microbes
Chemolithoheterotrophy
Energy source: Chemicals
Electron source: Inorganic e- donor
Carbon source: Organic carabon
Microorrganisms: some sulfur-oxidizing bacteria
Chemolithoautotrophy
Energy source: Chemicals
Electron source: Inorganic e- donor
Carbon source: CO2
Microorrganisms: some sulfur-oxidizing bacteria, iron-oxidizing bacteria, methanogens, nitrifying bacteria
Photolithoautotrophy
Energy source: Light
Electron source: Inorganic e- donor
Carbon source: CO2
Microorrganisms: cyanobacteria, purple and green sulfur bacteria
Photoorganoheterotrophy
Energy source: Light
Electron source: organic e- donor
Carbon source: Organic carabon
Microorrganisms: purple and green non-sulfur bacteria
Groupings of Phototrophic bacteria
cyanobacteria, Anaerobic anoxygenic (purple non/sulfur, green non/sulfur, heliobacterium), aerobic anoxygenic, oxygenic, prochlorophytes
objectives of microbio ecology
biodiversity and measure activities in nature
Activities measured in microbio ecology
1) primary production
2) Decomposition
3) biogeochemical cycling of elements
Microorganisms in nature
- live in common habitats suited to higher organisms as well as in extreme environements
- need resources and physiochemical conditions for growth
Psychrophiles, thermophiles, hyperthermophiles
live in habitats of extreme temps
halophilic archaea
red colour due to microbial pigments
niche
role of an organism in an ecosystem containing the physical habitat, functional role, and interactions
Microenvironment
place where microbes live and metabolize, contain physiochemical gradients - with spatial, temporal variability
Nutrient levels and growth rate
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
Biofilms
community of microorganisms embedded in matrix of extracellular polymeric substances adhering to the surface
advantages to biofilms
-protection, immune system cells, stay in a fav niche, nutrient trapping
disadvantages to biofilms
-competitive, localized biomass = easy predation, infection by viruses
problems from biofilm formation
-pipe clogging, corrosion, disease
exploitation of biofilms
slow filtration, microbial leaching of low grade ores, vinegar production
microbial mats
communities of mainly photosynthetic or chemolithotrophic bacteria
cyanobacterial mats
population of photosynthetic primary consumers and producers
- green layers: cyanobacterial layers
- orange: layers of anoxygenic phototrophic bacteria
Negative effects between interacting microbial populations
-competition and antagonism (specific inhibitor or metabolic product impedes growth/metabolism
Positive effects between interacting microbial populations
cooperative interactions
1) syntrophy, work together, one cant function without the other
2) carry complementary metabolic interactions eg. nitrification
symbiosis
intimate relationship between two organisms
1) mutualism- both species benefit
2) parasitism- one benefit, other harmed
