Bacterial Spermosphere Inoculants Alter N. benthamiana-Plant Physiology and Host Bacterial Microbiome.

In this study, we investigated the interplay between the spermosphere inoculum, host plant physiology, and endophytic compartment (EC) microbial community. Using 16S ribosomal RNA gene sequencing of root, stem, and leaf endophytic compartment communities, we established a baseline microbiome for Nicotiana sp. Phenotypic differences were observed due to the addition of some bacterial inoculants, correlated with endogenous auxin loads using transgenic plants expressing the auxin reporter pB-GFP::P87. When applied as spermosphere inoculants, select bacteria were found to create reproducible variation within the root EC microbiome and, more systematically, the host plant physiology. Our findings support the assertion that the spermosphere of plants is a zone that can influence the EC microbiome when applied in a greenhouse setting.

Toxicity evaluation of hospital laundry wastewaters treated by microbial fuel cells and constructed wetlands.

Hospital laundries generate high wastewater volumes with the presence of several contaminants. Nevertheless, few studies have investigated the toxicity of these effluents and looked for treatment alternatives that might reduce this eventual toxicity. So, the present study assessed the performance of an integrated system combining a microbial fuel cell (MBFC) and a constructed wetland (CW) to reduce toxic effects of wastewaters generated at a hospital laundry. After collection, raw effluents remained 7 days at the first unit (MBFC) of integrated system. Afterward, they were transferred to the second unit (CW) unit where remained more 7 days totaling a hydraulic detention time of 14 days. The toxicity evaluation involved three different organisms: Daphnia magna (acute ecotoxicity), Lactuca sativa (phytotoxicity) and Allium cepa (phytotoxicity, cytotoxicity, mutagenicity, and genotoxicity). Got results revealed an extremely acute ecotoxicity against D. magna, high phytotoxic effects in the L. sativa and A. cepa assays, and genotoxicity in the A. cepa assay for the untreated effluents. Furthermore, no significant incidence of micronuclei was observed in the raw wastewaters. Regarding the treatment, after the first stage, it was possible to verify that MBFC reduced the toxicity of the wastewaters only in some tested assays (endpoints) while after the CW (second stage) the effluents presented a complete absence of toxicity of the investigated bioassays. Therefore, the use of the integrated system combining two environmentally friendly technologies can be considered promising, since both MBFC and CW presented a complimentary effect with excellent results regarding the reduction of the overall toxicity of hospital laundry wastewaters.