Nutrient agar slants and Brain Heart Infusion Agar

filiform

continuous, threadlike growth with smooth edges

echinulate

continuous, threadlike growth with irregular edges

beaded

nonconfluent to semiconfluent colonies

effuse

thin, spreading growth

arborescent

treelike growth

rhizoid

rootlike growth

Aerobes

require the presence of atmospheric oxygen for growth. Their enzyme system necessitates use of O2 as the final hydrogen (electron) acceptor in the complete oxidative degradation of high-energy molecules, such as glucose.

Microaerophiles

Require limited amounts of atmospheric oxygen for growth. Oxygen in excess of the required amount appears to block the activities of their oxidative enzymes and results in death

Obligate anaerobes

require the absence of free oxygen for growth because their oxidative enzyme system requires the presence of molecules other than O2 to act as the final hydrogen (electron) acceptor

Aerotolerant anaerobes

Are fermentative organisms, and therefore do not use O2 as a final electron accepto

Facultative Anaerobes

Can grow in the presence or absence of free oxygen. They preferentially use oxygen for aerobic respiration

Psychrophiles range

0-20 C (cold lovers)

Mesophiles

20-45 C (moderate lovers)

thermophiles

45-70 C (heat lovers)