Background
Ethnobotany
The use of higher plants in the treatment of disease is as old as
the art of healing itself. Isaiah of Biblical times suggested that
a plaster of figs be placed on boils as a treatment of this form
of infection. The Chinese have used plants and herbs for centuries
in the treatment of many diseases. Thousands of phytochemicals have
been isolated and several serve as plant defenses against microbial
infection (3). Preliminary studies showed that plants have antibacterial
properties but these studies were done over 60 years ago (2). The
idea of using plants was abandoned with the discovery of antibiotics
from soil bacteria. The widespread resistance of bacterial pathogens
to conventional antibiotics has prompted renewed interest in the
use of alternative natural microbial inhibitors such as amtimicrobial
peptides (AMPs). AMPs, termed bacteriocins, are ribosomally synthesised
polypeptides, which have bactericidal or bacteriostatic effect.
A variety of antimicrobial peptides have been discovered in recent
years including defensins, found in human skin, magainin, found
in frog skin, and squalamine, from the spiny dogfish shark.. Additionally,
the rise in foodborne infections has prompted renewed interest in
the use of alternative natural microbial inhibitors.
Questions:
-Effects on bacterial/fungal growth of sublethal concentration(s)
of an extract of berries, leaves, etc. Must include a growth curve.
-Determine the Minimal inhibitory concentration (MIC) and/or minimal
lethal concentration (MLC) of an extract.
-What is your control?
Possible plants:
Insect galls (Baccharis, Salix, or Quercus).
Heteromeles arbutifolia
Heracleum maximum
Anaphalis margaritacea
Eriophyllum staechadifolium
Baccharis pilularis
Delairea odorata |
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Cultures available:
Aspergillus sp.
Candida spp.
Escherichia coli
Micrococcus luteus
Salmonella enterica
Shigella sonnei
Staphylococcus aureus
Saccharomyces cerevisiae
Penicillium sp.
Pseudomonas aeruginosa
Streptococcus pneumoniae
Streptococcus pyogenes
Streptococcus mutans |