GROWTH OF MICROORGANISMS
How do the little bugs grow?
Outline
Vocabulary warning Physical Requirements Chemical Requirements Patterns of Growth Measurements of Growth
Vocabulary Warning
There is a lot of vocabulary in the next two chapters
Much of the vocabulary is very specific in meaning and descriptive
These terms are extremely relevant to clinical microbiology and are part of the professional lexicon of the field.
Physical Parameters of Growth
Like all machines, microbes have operational conditions.
Though microbes dominate every niche on the planet, not all microbes are everywhere.
The physical conditions of growth are directly linked to physiology.
Example of Physical Parameters
0° C
10° C
37° C
100° C
= Psycrophile
= Psycrotroph
= Mesophile
= Thermophile
= Hyperthermophile
Other types of physical conditions Salt concentration
Halophile pH
BasophileAcidophile
Water ConcentrationXerophile
Why do these boundaries exist?
Structural Integrity of Cell Components Protein Denaturation Chicken and Egg Problem Natural Environment of Cells
The Story of Hansen’s Disease
Chemical Requirements for Growth. What elements do we need to form the
major macromolecules?
Carbon Nitrogen Sulfur Phosphorus
What about Oxygen and Hydrogen? Both can be gotten from water. Oxygen is a special case
Aerobe – organism that requires oxygen (O2)
Anaerobe – organism that does not require oxygen (O2)
Modifying LanguageObligateFacultative
Carbon, Nitrogen, Sulfur, and Phosphorus Heterotroph vs. Autotroph Must be present in a usable form
Is this everything you need to make a cell?
Other Components
Trace Elements (i.e. metals) Vitamins Unique Compounds
Types of Media
Complex Media
Defined Media
Can we culture everything?
NO, many things remain unculturable in today’s micro lab and these are proving to be some of the most interesting organisms.
Pattern of Growth
= Log Phase
= Stationary Phase
= Death Phase
= Lag Phase
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 200
2000
4000
6000
8000
10000
12000
Time (hrs.)
Nu
mb
er o
f B
acte
ria
(X10
0)
Caveats to Model
Small Initial Inoculum Media can be utilized Culture is not used to the media
Generation Time, how can you calculate it?
Explain this data
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 200
2000
4000
6000
8000
10000
12000
Measuring Growth
Direct
Indirect
