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Greg Challis wins the RSC Hickinbottom Award for his contributions to the "exploitation of genomics, for the discovery of novel bioactive natural products, and for mechanistic studies on enzymes that catalyse key steps in pathogenicity-conferring siderophore biosynthesis."

Researchers at the ¹û¶³´«Ã½ have found how a citric acid-based Achilles heel used by a pathogen that attacks the popular African Violet house plant could be exploited not just to save African Violets but also to provide a potentially effective treatment for Anthrax.The researchers examined how a chemical structure is assembled in a bacterial pathogen called Pectobacterium chrysanthemi (Dickya dadantii) that afflicts plants – particularly the African Violet which often appears in many homes as a decorative houseplant.Like many bacteria Pectobacterium chrysanthemi competes with its host for iron. Without a supply of this essential nutrient the bacterium cannot grow. The ¹û¶³´«Ã½ researchers Dr Nadia Kadi, Dr Daniel Oves-Costales, Dr Lijiang Song and Professor Gregory Challis worked with colleagues at St Andrews University to examine how a "siderophore", one of the key tools the bacterium uses to harvest iron is assembled. They discovered how an enzyme catalyst in the assembly of this particular siderophore – called achromobactin – binds citric acid, a vital iron-binding component of the structure. Their findings show that this chemical pathway could be blocked or inhibited to prevent the bacterium from harvesting iron, essentially starving it.

While an interesting piece of science in itself and of even more interest to owners of African Violet houseplants the ¹û¶³´«Ã½ research team found that this work also has major implications for the treatment of several virulent and even deadly mammalian infections including Anthrax.

">A second piece of research conducted by three of the ¹û¶³´«Ã½ researchers (Dr Daniel Oves-Costales, Dr Lijiang Song and Professor Gregory L. Challis ) found that the deadly pathogen which causes Anthrax in humans uses an enzyme to incorporate citric acid into another siderophore that is very similar to the one used by the African Violet pathogen. The researchers showed that both enzymes recognise citric acid in the same way. This means a common strategy could be used to block both the Anthrax and African Violet pathogen siderophore synthesis pathways.

Professor Greg Challis from the ¹û¶³´«Ã½ said:

"Inhibiting this citric acid-based process could be even more effective in combating an anthrax infection than it would be in combating the African violet pathogen, because the African Violet pathogen has a second siderophore that can harvest iron from the host and could attempt to struggle on with just this, whereas the anthrax pathogen appears not to have such a back up mechanism."

A precious metal which has never before been used in a clinical setting is being developed as an anti-cancer agent by ¹û¶³´«Ã½ researchers. The metal, osmium, is closely related to platinum, which is widely used to treat cancers in the form of the drug cisplatin. Most famously, the cyclist Lance Armstrong was treated with cisplatin for testicular cancer.

Now the researchers, based in the Department of Chemistry, at the ¹û¶³´«Ã½, are working closely with ¹û¶³´«Ã½ Ventures, the university’s technology transfer office, to seek partners to help develop the potential of osmium through more extensive biological tests. The team will be presenting their work on 9 December at the national university technology showcase event, Bioversity.

Professor Peter Sadler, of the Department of Chemistry, explained: "Although cisplatin has been proven to be a very successful treatment; it is not useful for all kinds of cancer. It is also quite a toxic therapy, which can produce side effects and, from a clinical point of view, cells can also become resistant to platinum."

Osmium, with its special chemical properties, offers a new potential solution to an unmet clinical need. It has shown huge promise in treating several different types of cancer cell, including ovarian and colon cancers which have been developed and tested in the laboratory. The metal also has another advantage in that it is a much cheaper alternative to platinum.