Strain 4AP-Y probably utilizes one of final metabolites from 3,4-dihydroxypyridine, i.e., formate, via the further degradation of this intermediate by other dominant strains. The phytotoxicity, absorption, and translocation of 4-aminopyridine in corn and sorghum growing in treated nutrient cultures and soils have been examined by Starr C188-9 order and Cunningham [34].

Although aerobic and anaerobic degradation of 4-aminopyridine in soil had been expected, the authors found little evidence to support biodegradation. Our data Belinostat cell line reported here indicated that 4-aminopyridine can be mineralized by soil microbiota, and we identified bacteria possibly involved in the degradation. To further elucidate the degradation, we will need to establish culture conditions for the isolation of strain 4AP-Y to be able to study the enzymes involved in the degradation of 4-aminopyridine. Conclusions We isolated a 4-aminopyridine-degrading enrichment

culture from a normal soil sample, revealed the metabolic fate of 4-aminopyridine, and characterized the bacterial population in the culture. GC-MS analysis and growth substrate specificity indicated that 4-aminopyridine was probably metabolized to 3,4-dihydroxypyridine and that formate probably is one of metabolites. DGGE analysis revealed that the unculturable strain, Hyphomicrobium sp. strain 4AP-Y became more dominant with increasing 4-aminopyridine concentration in the culture and in the presence check details of formate and Elizabethkingia sp. 4AP-Z was dominant in the presence of 3,4-dihydroxypyridine. Hyphomicrobium sp. strain 4AP-Y, Elizabethkingia sp. 4AP-Z, and the culturable 3,4-dihydroxypyridine-degrading bacterium, Pseudomonas nitroreducens 4AP-A and Enterobacter sp. 4AP-G probably play important roles in 4-aminopyridine degradation. Acknowledgements We would like to thank Prof. Hirosato

Takiwaka for helping with the chemical synthesis of 3,4-dihydroxypyridine and NMR analysis. Electronic supplementary material Additional file 1: Table S1: Identification of strains in the 4-aminopyridine-degrading enrichment culture. Table S2. 16S rRNA gene analysis of the predominant bacteria in the 4-aminopyridine-degrading enrichment culture. Prostatic acid phosphatase (PDF 75 KB) Additional file 2: Figure S1: Alignment of the partial sequence of the putative 3-hydroxy-4-pyridone dioxygenase (PydA) from 3,4-dihydroxypyridine-degrading bacteria with sequences of previously reported PydAs. Figure S2. Micrograph of cells of the enrichment culture growing in medium containing 4-aminopyridine. (PDF 358 KB) References 1. Hollins RA, Merwin LH, Nissan RA, Wilson WS, Gilardi R: Aminonitropyridines and their N-oxides. J Heterocycl Chem 1996,33(3):895–904.CrossRef 2. Liu S-M, Wu C-H, Hung H-J: Toxicity and anaerobic biodegradability of pyridine and its derivatives under sulfidogenic conditions. Chemosphere 1998,36(10):2345–2357.PubMedCrossRef 3.