title: Use of plate-wash samples to monitor the fates of culturable bacteria in mercury- and trichloroethylene-contaminated soils.
abstract: With the ultimate aim of developing bioremediation technology that use the optimum bacterial community for each pollutant, we performed polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) and phylogenetic analysis and identified communities of culturable bacteria in HgCl(2)- and trichloroethylene (TCE)-contaminated soil microcosms. PCR-DGGE band patterns were similar at 0 and 1 ppm HgCl(2), but changes in specific bands occurred at 10 ppm HgCl(2). Band patterns appearing at 10 and 100 ppm TCE were very different from those at 0 ppm. Phylogenetic analysis showed four bacterial groups in the HgCl(2)-contaminatied cultures: Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes. Most high-density bands, decreased-density bands, and common bands were classified into the phyla Proteobacteria, Actinobacteria, and Firmicutes, respectively; the effects of HgCl(2) on culturable bacteria appeared to differ among phyla. Duganella violaceinigra [98.4% similarity to DNA Data Bank of Japan (DDBJ) strain], Lysobacter koreensis (98.2%), and Bacillus panaciterrae (98.6%) were identified as bacteria specific to HgCl(2)-contaminated soils. Bacteria specific to TCE-contaminated soils were distributed into three phyla (Firmicutes, Proteobacteria, and Actinobacteria), but there was no clear relationship between phylum and TCE effects on culturable bacteria. Paenibacillus kobensis (97.3%), Paenibacillus curdlanolyticus (96.3%), Paenibacillus wynnii (99.8%), and Sphingomonas herbicidovorans (99.4%) were identified as bacteria specific to TCE-contaminated soils. These bacteria may be involved in pollutant degradation.
authors.affiliation: National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Mera
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Iwasaki
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification; D015373:Bacterial Typing Techniques; D001431:Bacteriological Techniques / Q000379:methods; D001673:Biodegradation, Environmental; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D020459:Genes, rRNA; D008628:Mercury / Q000378:metabolism*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D014241:Trichloroethylene / Q000378:metabolism*
chemical_list: D003470:Culture Media; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D014241:Trichloroethylene; D008628:Mercury