Effect of 2,4-dinitrotoluene on the anaerobic bacterial community in marine sediment.
OBJECTIVE
To study the impact of added 2,4-dinitrotoluene (DNT) on the anaerobic bacterial community in marine sediment collected from an unexploded ordnance dumping site in Halifax Harbour.


RESULTS
Marine sediment was spiked with 2,4-DNT and incubated under anaerobic conditions in the presence and absence of lactate. Indigenous bacteria in the sediment removed 2,4-DNT with subsequent formation of its mono- and diamino-derivatives under both conditions. PCR-DGGE and nucleotide sequencing were used to monitor the change in the bacterial population in sediment caused by the presence of 2,4-DNT. The results showed that denaturing gradient gel electrophoresis banding patterns of sediment microcosms treated with 2,4-DNT were different from controls that did not receive 2,4-DNT. Bacteroidetes, Firmicutes and delta-Proteobacteria were present in sediment incubated in the absence of 2,4-DNT. However, several gamma-Proteobacteria became dominant in sediment in the presence of 2,4-DNT, two of which were 99% similar to Shewanella canadensis and Shewanella sediminis. In the presence of both 2,4-DNT and lactate, two additional delta-Proteobacteria were enriched, one closely related (98% similarity) to Desulfofrigus fragile and the other affiliated (96% similarity) to Desulfovibrio sp. In contrast, none of the above four Proteobacteria were enriched in sediment incubated with lactate alone.


CONCLUSIONS
Presence of 2,4-DNT led to a significant change in bacterial population of marine sediment with the enrichment of several gamma- and delta-Proteobacteria.


CONCLUSIONS
Our results provided the first evidence on the impact of the pollutant 2,4-DNT on the indigenous bacterial community in marine sediment, and provided an insight into the composition of bacterial community that degrade 2,4-DNT.
Yang
H
H
Biotechnology Research Institute, National Research Council Canada, Montréal, Québec, Canada.
Zhao
J-S
JS
Hawari
J
J
D001421:Bacteria, Anaerobic / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D002170:Canada; D004269:DNA, Bacterial / Q000235:genetics; D004136:Dinitrobenzenes / Q000633:toxicity*; D004591:Electrophoresis, Polyacrylamide Gel; D019015:Geologic Sediments / Q000382:microbiology*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D004269:DNA, Bacterial; D004136:Dinitrobenzenes; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical; C016403:2,4-dinitrotoluene