Project description:Fe(II) can be oxidized by mixotrophic nitrate-reducing Fe(II)-oxidizing bacteria to Fe(III), leading to mineral precipitation. However, the effects of this process on the metabolism and reproduction ability of the Fe(II)-oxidizing bacterial cells have not yet been quantified. In this study, we investigated the effects of Fe(II) on the mixotrophic nitrate-reducing Fe(II)-oxidizing bacteria Acidovorax sp. BoFeN1 by performing cell plate counts, chemical analyses, and scanning electron microscopy (SEM) imaging. The result showed that nitrate-reducing Fe(II)-oxidizing bacteria Acidovorax sp. BoFeN1 undergoes a striking physiological state in which respiration persists while cell reproduction collapses after their oxidation of Fe(II). Across 0.1–10 mM Fe(II), colony-forming units dropped by up to 103-fold, yet acetate consumption remained largely unaffected and nitrate reduction was even slightly promoted. SEM-EDS reveals extensive Fe(III) encrustation on cells. Adding an Fe(III) chelator, citrate, restored reproductive capacity without notably changes in Fe(II) oxidation or nitrate reduction, indicating that it was the products of Fe(II) oxidation, the secondary Fe(III) minerals, that impaired cell reproduction. These findings uncover a mineral encrustation-driven uncoupling between respiration and reproduction, suggest how natural organic ligands may buffer NRFeOx bacterial communities in Fe-rich anoxic environments, and point to cellular-level levers for mitigating denitrification failures and N2O risks in engineered and natural systems.
Project description:The effect of nitrate reduction (anaerobic cultivation in the presence of heme, vitamin K2 and nitrate) was compared with anaerobic cultivation supplemented with citrate (Lactobacillus plantarum). The medium was chemically defined medium with mannitol as main carbon source Two-condition experiment, nitrate vs citrate reducing cells. Biological replicates: 4 nitrate reducing cultures, 4 citrate reducing cultures, independently grown and harvested. Two slides were used, each slide contained 8 Arrays. Citrate reducing cultures are called reactor 1-4, Nitrate reducing cultures are called reactor A-D
Project description:The effect of nitrate reduction (anaerobic cultivation in the presence of heme, vitamin K2 and nitrate) was compared with anaerobic cultivation supplemented with citrate (Lactobacillus plantarum). The medium was chemically defined medium with mannitol as main carbon source
Project description:Nitrate-reducing iron(II)-oxidizing bacteria are widespread in the environment contribute to nitrate removal and influence the fate of the greenhouse gases nitrous oxide and carbon dioxide. The autotrophic growth of nitrate-reducing iron(II)-oxidizing bacteria is rarely investigated and poorly understood. The most prominent model system for this type of studies is enrichment culture KS, which originates from a freshwater sediment in Bremen, Germany. To gain insights in the metabolism of nitrate reduction coupled to iron(II) oxidation under in the absence of organic carbon and oxygen limited conditions, we performed metagenomic, metatranscriptomic and metaproteomic analyses of culture KS. Raw sequencing data of 16S rRNA amplicon sequencing, shotgun metagenomics (short reads: Illumina; long reads: Oxford Nanopore Technologies), metagenome assembly, raw sequencing data of shotgun metatranscriptomes (2 conditions, triplicates) can be found at SRA in https://www.ncbi.nlm.nih.gov/bioproject/PRJNA682552. This dataset contains proteomics data for 2 conditions (heterotrophic and autotrophic growth conditions) in triplicates.
Project description:Nitrate-reducing iron(II)-oxidizing (NDFO) bacteria are widespread in the environment contribute to nitrate removal and influence the fate of the greenhouse gases nitrous oxide and carbon dioxide. The autotrophic growth of nitrate-reducing iron(II)-oxidizing bacteria is rarely investigated and poorly understood. The most prominent model system for this type of studies is enrichment culture KS, which originates from a freshwater sediment in Bremen, Germany. A second NDFO culture, culture BP, was obtained with a sample taken in 2015 at the same pond and cultured in a similar way. To gain insights in the metabolism of nitrate reduction coupled to iron(II) oxidation under in the absence of organic carbon and oxygen limited conditions, we performed metagenomic, metatranscriptomic and metaproteomic analyses of culture BP. Raw sequencing data of 16S rRNA amplicon sequencing (V4 region with Illumina and near full-length with PacBio), shotgun metagenomics, metagenome assembly, raw sequencing data of shotgun metatranscriptomes (2 conditions, triplicates) can be found at SRA in https://www.ncbi.nlm.nih.gov/bioproject/PRJNA693457. This dataset contains proteomics data for 2 conditions in triplicates. Samples R23, R24, and R25 are grown in autotrophic conditions, samples R26, R27, and R28 in heterotrophic conditions.