African clawed frog
In March 1995 Westerhoff wrote about a discovery of magainin in the African clawed frog which helps it fight against bacteria which he discovered along with his colleagues. In December 1996 he and his group discovered a nitric-oxide reductase of "Paracoccus denitrificans". In 2000 he and Martin Bier, along with Barbara Bakker discovered that yeast cells can oscillate and merge with others in some cases because they get energized from glycolysis. In 2013 he studied maps of human metabolism and came out with its biochemical map.