Assistant research fellow Raymond Staals (left) and Dr
Peter Fineran, of the University of Otago microbiology and
immunology department, continue their research. Photo by
Research involving University of Otago scientists has
shed new light on a ''surprisingly flexible'' immune system
which has enabled bacteria to survive a multibillion-year-long
arms race with viruses.
A team co-led by Dr Peter Fineran, of the Otago department of
microbiology and immunology, and by scientists from the
Netherlands, have been studying the genetic basis of adaptive
immunity in E. coli and other bacteria.
Through their recent collaboration, they have found these
bacterial immune systems were much more robust and responsive
to viruses than previously thought.
Their ''really exciting'' joint findings had appeared in the
leading US journal PNAS, Dr Fineran said.
Better understanding the bacterial immune system could
eventually help reduce the growth of bacterial resistance in
individual patients and could identify new targets for
The researchers are investigating an adaptive immune system -
termed CRISPR-Cas - which is found in half of all bacterial
species and in most single-celled microbes in the archaea
The system creates a genetic memory of specific past
infections by viruses and plasmids.
Plasmids are small DNA molecules that can move between
Dr Fineran said the system stole samples of the invader's
genetic material and stored them so it could recognise future
exposures and neutralise the attack.
The Otago research showed this detection system could
recognise a previously encountered ''invader'', even if later
mutation meant the intruder was up to 30% different from
This was equivalent to a human being recognised on a security
camera during a later visit to a building despite being
disguised, such as by wearing sunglasses.
It had previously been thought subsequent immune recognition
could occur if there was only about a 3% change in appearance
by the invader.
''It's a remarkably flexible and robust immune system for
such simple single-celled organisms.''
This system reflected the 3.5 billion-year ''co-evolutionary
arms race'' between bacteria on one side, and viruses and
plasmids on the other, he said.
Dr Fineran's research was supported by a Rutherford Discovery
Fellowship from the Royal Society of New Zealand.