Searching for Antibacterial Properties in Local Lichen

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Searching for Antibacterial Properties in Local
Lichen

• Independent Microbiology Project
• By Cara Cherry

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Idea for Project

• Insert blurb from plant book

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Plant Bio Refresher Moment

• What is a lichen?
• Symbiotic relationship between a green
  algae/cyanobacteria and a fungus (an ascomycota)

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Hiking for Lichen

• Grow on tree bark, decaying tree limbs, rocks,
  buildings, etc.
• Found specimens in Guion Woods and surrounding
  area

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Specimen I Found

• Candelaria efflorescens
• Found on a light post outside Guion

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Specimen I Found

• Pyxine soredata
• Found on tree limb in Guion Forest

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Specimen I Found

• Maculina subtinctoria
• Found on a tree limb in Guion Woods

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Specimen I Found

• Flavoparmeta caperata
• Found on a tree limb in Guion Woods

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Specimen I Found

• Imshaugia deurites
• Found on tree trunk in Guion Woods

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Extraction of Lichen Compounds

• Air-dried lichen
• Ground with mortar and pestle
• Measured out 1 gram of each lichen
• Soaked 1 gram of lichen with 50 mL of acetone in
  a sealed beaker for 24 hours

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Extracts
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Bacteria Species Used
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Investigation of Antibacterial Properties

• Soak 10 µL of lichen extract on a sterile filter
  paper disk
• Make 2 spread plates for each of the bacteria
  being tested
• Divide one plate into 4 quadrants and the other
  into three
• Place a lichen extract filter disk in each
  quadrant, leaving one quadrant free to place
  acetone-soaked filter disk as a control
• Incubate at 37C for 24 hours
• Record results

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Results
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S. aureus Plates
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B. subtilis Plates
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Results

• 2 out of 5 lichen tested had antibacterial
  properties (Pyxine soredata and Flavoparmeta
  caperata)
• Only effective on gram positive organisms
• B. subtilis (rod) is more inhibited by these
  species of lichen than is S. aureus (cocci)

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Areas for Future Research

• Identify lichen compounds using TLC
• Determine the cause of the variation in
  inhibition among gram positive bacteria
• Test more species of lichen

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Just for Grins and Giggles

• I tested the lichen for antifungal activity
• Lichen extracts have no affect on fungus