[Remediation of Decabromodiphenyl Ether Contaminated Sediment Through Plant Roots Enhanced by Exogenous Microbes].

Decabromodiphenyl ether (BDE-209), a main ingredient of brominated flame retardants, has drawn more and more attention because of the pollution it caused in sediment. A pot experiment was conducted in a greenhouse to investigate the impact of Brevibacillus brevis and Enterococcus casselifavus on the enhancement of phytoremediation by Thalia dealbata, which is common in the river bank and was found to be an effective plant for BDE-209 removal. The concentration of organic acids, the amount of microorganisms and the ability of carbon utilization of soil microorganisms in different experimental groups were analyzed. The results showed that the removal rate of BDE-209 in the exogenous microbes containing groups were higher than that of the control. And B. brevis presented the highest enhancement of phytoremediation with the removal rate rising highest to 66% compared with the control (non-rhizosphere group 37.93% and no plant group 39.27%) after 60 days. The removal of BDE-209 in sediment, quantity of microorganism, concentration of organic acids and the ability of carbon utilization of soil microorganisms in rhizosphere sediment were higher than those in non-rhizosphere sediment.

A Comparison of Anammox Bacterial Abundance and Community Structures in Three Different Emerged Plants-Related Sediments.

Quantitative polymerase chain reaction (qPCR) assays and 16S rRNA gene clone libraries were used to document the abundance, diversity and community structure of anaerobic ammonia-oxidising (anammox) bacteria in the rhizosphere and non-rhizosphere sediments of three emergent macrophyte species (Iris pseudacorus, Thalia dealbata and Typha orientalis). The qPCR results confirmed the existence of anammox bacteria (AMX) with observed log number of gene copies per dry gram sediment ranging from 5.00 to 6.78. AMX was more abundant in T. orientalis-associated sediments than in the other two plant species. The I. pseudacorus- and T. orientalis-associated sediments had higher Shannon diversity values, indicating higher AMX diversity in these sediments. Based on the 16S rRNA gene, Candidatus 'Brocadia', Candidatus 'Kuenenia', Candidatus 'Jettenia' and new clusters were observed with the predominant Candidatus 'Kuenenia' cluster. The I. pseudacorus-associated sediments contained all the sequences of the C. 'Jettenia' cluster. Sequences obtained from T. orientalis-associated sediments contributed more than 90 % sequences in the new cluster, whereas none was found from I. pseudacorus. The new cluster was distantly related to known sequences; thus, this cluster was grouped outside the known clusters, indicating that the new cluster may be a new Planctomycetales genus. Further studies should be undertaken to confirm this finding.

Molecular characterization and biological response to respiration inhibitors of Pyricularia isolates from ctenanthe and rice plants.

The molecular profile and the biological response of isolates of Pyricularia oryzae Cavara obtained from ctenanthe to two strobilurins (azoxystrobin, kresoxim-methyl) and the phenylpyridinamine fungicide fluazinam were characterized, and compared with isolates from rice plants. Five different isozymes (alpha-esterase, lactate, malate, isocitrate and sorbitol dehydrogenases) and five random decamer primers for RAPD-PCR were used to generate molecular markers. Using unweighted pair-group with arithmetic average analysis, ctenanthe isolates were found to form a separate group distinct from that of the rice isolates for both sets of markers. Amplified polymorphic sequences of mitochondrial cytochrome b that were digested with Fnu4HI or StyI revealed no differences among Pyricularia isolates at amino acid positions 143 or 129 which confer resistance to strobilurins in several fungi. In absence of the alternative respiration inhibitor salicylhydroxamic acid (SHAM) the three fungicides showed inferior and variable efficacy, with a trend toward the rice isolate being less sensitive. The addition of SHAM enhanced the effectiveness of all fungicides against isolates regardless of their origin. Appressorium formation was the most vulnerable target of action of the respiration inhibitors and azoxystrobin the most effective. This is the first report of a comparison between the molecular profiles and sensitivities to respiration inhibitors for Pyricularia oryzae isolates from a non-gramineous host and from rice.