In
search of ways to fight antibiotic-resistant bacteria, Australian scientists
are analyzing synthetic antimicrobial skin secretions of Australian Green-Eyed
and Growling Grass frogs.
These
two species were selected because peptides secreted from their skin form a defense
to a broad spectrum of bacteria including Staphylococcus.
Commonly
known as superbugs, antibiotic-resistant bacteria can pose significant risks to
human health. Data on the MyHospitals Website shows in Australian hospitals
there are around 7,000 Staphylococcus
aureus bacterium infections alone each year.
The
cutting-edge research is underway at the Australian Nuclear Science and
Technology Organisation (ANSTO), with scientists using neutrons from Australia’s
only nuclear reactor.
The
project is being led by Professor Frances Separovic from the School of Chemistry
at the University
of Melbourne, using
expertise of ANSTO’s Postdoctoral Research Fellow, Anton Le Brun, and Professor
Michael James.
“With
the increase in antibiotic resistance, peptides (small proteins) that destroy
cell membranes are being considered as therapeutics. However, there is a need
for peptides that preferentially destroy bacterial membranes,” Separovic said.
“We
have characterized several peptides from the skin glands of Australian tree
frogs. These peptides are host defense compounds, which have strong
antibacterial activity.
“By
understanding their 3D structure and mechanism of action at the molecular level,
we may be able to increase their antibiotic potency and specificity.”
Le
Brun explained there are three questions that need to be answered when studying
the active ingredients of the secretions or antimicrobial peptides:
“Firstly,
we’re using facilities at the OPAL reactor to analyze how and why the peptides
from the frog skin secretions work, and how they are efficient at killing
bacterial cells,” Le Brun said.
“And,
of course, given that we don’t want them to attack healthy human (or frog) cells,
we also need to establish whether and how these antimicrobial peptides are
selective for bacterial cells.
“The
OPAL reactor and neutron reflectometer will help us provide further information
to answer those questions, and research possible alternative treatments or
cures for superbugs.
“With
neutron reflectivity, we can individually detect both the peptide that attacks
the cell membrane of bacteria, and the membrane itself—providing a better
picture of the process.
“It’s
this component by component analysis that will help us understand how two
different types of frog peptides from two different types of frogs deliver the
same outcome: dead bacteria.”
