Metabolic Diversity Two fundamental nutritional needs: 1.Acquiring chemical energy in the form of...
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Transcript of Metabolic Diversity Two fundamental nutritional needs: 1.Acquiring chemical energy in the form of...
Metabolic Diversity
• Two fundamental nutritional needs:1.Acquiring chemical energy in the form of ATP– Pump ions, move cargo, undergo chemical
reactions in the cell
2.Obtaining carbon– Used to synthesize fatty acids, DNA, RNA, and
other molecules
Culturing Techniques
• Researchers use specific compounds and substrates in the culture medium and observe what grows!
• MacConkey agar– Isolates enteric, Gram-negative, bacteria based on
their ability to ferment lactose
SIM Test
• S = Sulfur reduction
• I = Indole production– Kovac’s reagent
• M = Motility
Simmons Citrate Test
• Tests the ability of certain organisms to utilize citrate as a carbon source.
• pH indicator = Bromthymol blue– pH > 7.5 turns royal blue– Neutral pH green (just like uninoculated media)
Christensen Urea Test
• Some bacteria utilize urea, which results in the formation of ammonia.– Alkaline• Produces a red-pink/red-violet color
– A negative reaction will have no color change and the agar medium will remain pale yellow.
Identifying Specific Bacteria
Bacteria Genus
Sulfur Indole Lactose Citrate Urease
Escherichia - + + - -Edwardsiella + + - - +/-Salmonella + - +/- + -Enterobacter - - + + +
Water Quality Index
• Fecal coliform measurements:1. Multiple-Tube Fermentation
– Most Probable Number (MPN)
2. Membrane Filtration– Measures both Total Coliform and E. coli
Membrane Filtration using mColiblue