Weedkiller spur for TB research

By MICHAEL OTTO

New Zealand researchers are using the idea behind a popular weedkiller to find a better treatment for tuberculosis.

The University of Canterbury scientists are trying to develop ways to block enzymes needed by the TB bug for growth and are working on a technique that is similar to the way in which Roundup stops plant growth.

Associate Professor Andrew Abell's team in the department of chemistry are hoping their method might be used to selectively target the bacteria responsible for tuberculosis and leave alone useful bacteria like E.coli which occur naturally in the stomach.

Tuberculosis kills three million people a year worldwide. Four people died from TB in New Zealand last year.

"People might be a bit surprised at a potential pharmaceutical link to a herbicide," said Professor Abell. "It is certainly an unusual linkage."

Roundup's essential ingredient - glyphosate - blocks an enzyme that is needed to help assemble the aromatic amino acids that are key building blocks of proteins in plants. Proteins are needed by bacteria for growth.

The Canterbury researchers are trying to block another enzyme - dehydroquinase - that also plays a part in building aromatic amino acids.

The building of these acids occurs only in plants and microbes - not in animals. Humans have to obtain aromatic amino acids through their diet.

Dehydroquinase has two forms, so the method can target bacteria that have one form while leaving alone bacteria that have the other.

The three-year Marsden Fund-supported research is a joint study between Canterbury and Cambridge (UK) labs.

The research was at an early stage, but testing had begun, said Professor Abell.

"We have established a connection in the US and are now testing with tuberculosis."

A potential area for development of these methods was in inhibiting an enzyme that played a part in forming cataracts of the eye.

Associate Professor Mark Thomas, of the University of Auckland School of Medicine, said tuberculosis had been effectively controlled in New Zealand because of good public health measures like ensuring patients stuck to their treatments.

He thought the Canterbury research sounded like "a pretty useful idea".