Chemical changes turn milk protein into a Listeria killer

Media Release, Monday 7 August 2006

Higher order taxa Bacteria; Firmicutes; Bacilli; Bacillales; Listeriaceae; Listeria Species Listeria monocytogenes, L. innocua, L. grayi, L. ivanovii More Information ROLLOVER

PhD research by Yu (Cindy) Pan has found that chemically modifying the protein lactoferrin substantially boosts its ability to fight off the food poisoning bug Listeria.

Listeria can cause miscarriages in pregnant women and extremely serious illnesses in children, the elderly and those with suppressed immune systems.

The protein modified by Ms Pan also fights off the bacteria Pseudomonas fluorescens, one of the most common causes of food spoilage.

“Lactoferrin is quite an amazing protein, which has been shown to have strong immune, anti-viral and anti-inflammatory effects,’’ says Ms Pan.

“My research aimed to find out if its antibacterial effects could be increased by modifying the protein.

“I found that by using a reaction called amidation – which increases the positive charge on the protein, lactoferrin’s anti-bacterial properties were at least 100 times stronger than in its native form.’’

Ms Pan said further studies were needed before the modified proteins could be consumed by humans, but the initial findings were very promising.

“The research shows that there is also great potential to modify other cows’ milk proteins to impart antimicrobial properties to them,’’ she said.

“Potentially these anti-bacterial proteins could be used to complement or even replace traditional medical treatments of bacterial infections, particularly those caused by bacteria that have become resistant to antibiotics.’’

Ms Pan’s research also found that the protein β-lactoglobulin - not previously shown to have any anti-bacterial properties – could fight off another common food spoilage agent Bacillus subtillis once chemically modified.

Ms Pan’s supervisor Hubert Roginski, of the Faculty of Land and Food
Resources, said she had made some important new findings.

“Ms Pan has created killer proteins against invading bacteria,’’ he said.

“Her research has the potential to extend the shelf life of foods by creating proteins that can be added to them to keep some of the most common contaminants in check and stop them from multiplying,’’ he said.

Ms Pan’s study broadens possibilities of further research that may ultimately generate modified proteins and peptides with a potential for use in treatment of bacterial infections in animals and humans.

Her research was conducted as part of a collaboration between the University of Melbourne’s Faculty of Land and Food Resources, Food Science Australia and Australian Animal Health Laboratory. Dr John Coventry, Dr Wojtek P Michalski, Dr Jason Wan and Dr Alvin Lee were her co-supervisors from these research institutions.

Ms Pan will be conferred with a PhD by the University of Melbourne on Saturday 12 August.

Source / Credit: University of Melbourne