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 Basophile Acidophile  Water Concentration Xerophile

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 (O 2 ) Anaerobe – organism that does not require oxygen (O 2 )  Modifying Language Obligate Facultative

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

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

Measuring Growth  Direct  Indirect