- Comparative analysis of nitrifying bacteria in full-scale oxidation ditch and aerated nitrification biofilter by using fluorescent in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE). Mertoglu, B., Calli, B., Girgin, E., Inanc, B., Ozturk, I. Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering. (2005)