L2: Microbial Ecology goals, components and challenges

Question 1

List important environmental compontents of microbes

Answer 1

ESC We Love Nature 2

1. Energetics: something to oxidize/reduce
2. Surfaces to colonize (biofilms)
3. Conditions: light, pH, temp
4. Water in liquid form
5. Light: as an energy source for phototrophs
6. Nutrients
7. Nutritional Categories: energy, electrons, carbon, glucose

Question 2

What is the use of Nutrients?

Answer 2

• environmental component microbes use like CNPS, cations, anions, metals

*used for metabolic function to generate energy (chemotrophs) or carbon source (heterotrophs)

Question 3

Name two key environmental components, their use, types, and source (1)

Answer 3

1. Electron donors (something to oxidize)
   * source of e- biosynthesis
   * organic (organography, carbohydrates) vs inorganic: lithography (metals, ammonia)
   * energy source of chemotrophs when energy is conserved in electron stropping

Question 4

Name another key environmental component, their source (2)

Answer 4

2. electron acceptors, something to reduce
   * aerobic/anaeobic respiration, phototrophy, methanogenesis
   *organic (organic acids)
   *inorganic (O2, NO3, SO4)

Question 5

What do autotrophs or chemotrophis need metabolic energy for

Answer 5

energy needed to maintain membrane potential for ATP, biosynthesis, transport functions, amino acids, enzymes, DNA, RNA cellular structures

Question 6

Describe early microbial ecology

Answer 6

• hard to study microbes in natrual environment
• required isolation/culture experiments as pure cultures
  *most species are not culturable

Question 7

Explore current microbial ecology

Answer 7

• uses culture-based and molecular methods to study communities
  *must still culture because characterisation alone is not enough

Question 8

What are the objectives of studying microbial populations?

Answer 8

determine metabolic functions DIQC

1. Detect: determine the microbe is present in the sample via PCR, microscopy, metagenomic sequencing
2. Identity: identity which organisms (taxonomy) with or without culture
3. Quantity: relative numbers of different groups of microbes, pop size, fluctuations via molecular methods
4. Characterise: characterise the physiological and ecological functions of diff members, the biggest challenge

Question 9

List the challenges in achieving microbial ecology goals

Answer 9

1. live vs dead AND active vs inactive
2. molecular techniques do not different between living or ideas cells more for gene expression (RT PCR)
3. microscopy cant different live/dead or active
4. culture can enrich species that were not active/dominant or transiently in the environmental
5. stable istope probing are being developed to distinguish dead/live vs inactive/inactive problems