Topic 12 - Environmental Microbiology

Question 0

How does it relate to my course?

Answer 0

Antibiotic discovery most from soil bacteria and fungi

Crop health

Question 1

What is environmental microbiology ?

Answer 1

Study of the interactions of microbes in their natural habitats 
Encompasses biotic ( living ) and abiotic ( non living )

Question 2

Where are the microorganisms?

Answer 2

Biosphere (encompasses all ecosystems below)
Atmosphere
Lithosphere
Hydrosphere

Question 3

Atmosphere

Answer 3

Air

• Difficult enviroment for microbes
• Lack of nutrients moisture and surfaces
• Mainly dispersal of spores ect

Question 4

Why are microbes able to live in a variety of habitats ?

Answer 4

Due to Microbial diversity

• Use a variety of carbon and energy sources
• Grow under different physical conditions

Question 5

Extremeophiles

Answer 5

Live in extreme environments

• pH
• temperature
• pressure
• salinity

Question 6

Lithosphere

Answer 6

soil/ earths crust

Question 7

Extreme environments

Answer 7

Survival of adapted micro organisms in extreme envioment

Question 8

Thermotolerant enzymes

Answer 8

DNA polymerase used in PCR

Taq DNA polymerase from thermus aquaticus

Question 9

Solubilising mineral for extraction

Answer 9

Eg uranium iron copper and gold mining

Eg thieobaccillus ferroxidans now acidothiobacillus ferrooxidans

Question 10

Bioremediation

Answer 10

Break down Toxic and difficult to break down chemicals

Break down oil spills

Question 11

Identify 2 extreme habitats

Answer 11

Thiobaccillus used in mining low grade copper ores
Salt lakes eg halobacterium salinarum
High salt ( saturation about 35%)

Question 12

Define symbiosis

Answer 12

Two differing organisms living together in close association that is beneficial to one or both of them

Question 13

Examples of symbiosis

Answer 13

Ruminants bacteria enable animals to digest cellulose in grass
Mycorrhizae - fungi living in close association with plant roots

Question 14

Mycorrhizae -

Answer 14

fungi living in close association with plant roots extend effective surface area of roots solubilise po4 -3 and provide it for plants
commercial uses eg grow faster trees and truffles

Question 15

Commercial uses of Mycorrhizae

Answer 15

Inoculated seeds grown faster and to grown truffles

Question 16

Define biogeochemical cycles

Answer 16

Recycling (oxidation and reduction) of chemical elements between the living ( biotic) and the non living (abiotic ) environment

Question 17

Soil microbiology

Answer 17

Soil consists of mineral particles ( clay silt sand gravel)
51% total volume
Organis matter plant and animal derived 9% total volume
Living organisms 1% of total volume

Question 18

Profile of mature soil

Answer 18

A horizon most of the microorganism and most organic material
B horizon little organism material and few microorganisms
C horizon parent material low microorganisms

Question 19

Most commons soil inhabitants

Answer 19

Fungi and bacteria

Question 20

Where is the highest density of microbes ?

Answer 20

On or Within 5mm or root

Question 21

Soil inhabitants

Answer 21

Extremely diverse
Chemo heterotrophic
-arthrobacter, bacillus, clostridium,
Chemo autotrophic

Question 22

What causes the sweet earthy smell after rain?

Answer 22

Streptomyces - release a compound called geosmin

Question 23

What percentage of soil microbes can be cultured from the soil

Answer 23

10% if in a good lab

Question 24

Fungi

Answer 24

Better able to tolerate dissiccation than bacteria
Carbon recyclers/decomposers saprophytes
Predominant genera
Mucor, penicillium , aspergillus
Yeasts and moulds

Question 25

Cyanobacteria

Answer 25

Important in carbon cycling
Can fix nitrogen
E rice paddies benefit from nitrogen fixation by Cyanobacteria
Environmental hazard- toxic blooms in water
Certain species produce microcystin toxins which can kill animals and people

Question 26

How would nutritn and respiration of microorganisms change with depth of soil

Answer 26

More anaerobic bacterial; sulfur ( sulphur- reducing bacteria) and methanogens(archea)

Question 27

Where apa from top layer of soil would you expect high organisms

Answer 27

Rhizosphere

Question 28

Methods of study of soil micro organisms

Answer 28

Special methodologies required due to the complexities of the soil environment
Method may include
Isolation and identification( different categories of media( selective and enriching )
Enumeration (counting)
Metagenome analysis ( DNA sequencing of microbes )
Biological activity ( if I put a compund on what happens / what gases are released what is broken down )

Mostly use a combination of these methods

Question 29

Selective media

Answer 29

Discourage the growth of unwanted organisms by addition of inhibitory compounds
Eg macConkey agar
Contain bile salts which are selective for enteric bacteria

Question 30

Enrichment media

Answer 30

Addition of substrate that encourages growth of organisms of interest ( always a liquid media )

Question 32

Hydrosphere

Answer 32

Water

Marine

Question 62

Lithosphere

Answer 62

Soil

Earths crust