Bacteria…Bacteria EVERYWHERE!!! Habitat - environment or place where organisms thrive Optimal conditions - ideal temperature, humidity, nutrients Where???? on the tops of mountains the bottom of the deepest oceans in the guts of animals even in the frozen rocks and ice of Antarctica MOST bacteria serve essential ecological roles 1) Decomposition - breakdown of organisms, release nutrients back into the environment 2) cycling of nitrogen PATHOGENIC BACTERIA PATHOGENIC BACTERIA - cause disease

Classifying….again!!!

More ways to classify bacteria???? Three groups based on response to gaseous oxygen: Aerobic require oxygen for continued growth and existence Anaerobic cannot tolerate oxygen Facultative anaerobes - prefer growing in the presence of oxygen, but can continue to grow without it Gram stain - type of stain based on lipid content of the cell wall: Gram positive - stains blue Gram negative - stains red

Gram positive bacteria will be blue/purple/violet. Gram negative bacteria will be light pink.

Gram positive cocci Staphylococcus aureus 1000x

Gram negative bacillus (rods) Escherichia coli 1000x

Yersinia pestis in the blood

A little culture….. CULTURE Bacteria grow in a controlled environment provide required nutrients in” agar” provide required temperature by using an incubator monitor the colonial growth in a petri dish

Bacterial Colonies Color - white, yellow, gray Size - large, small, medium Edges - smooth, regular, irregular Texture - creamy, crunchy, dry, gooey

Smooth colonies with regular edgeRough colonies with irregular edge OtherOther examples

Blood Hemolysis Alpha hemolysis Beta hemolysisNo hemolysis