| 1. |
- Christel, Stephan, et al.
(författare)
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Comparison of Boreal Acid Sulfate Soil Microbial Communities in Oxidative and Reductive Environments
- 2019
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Ingår i: Research in Microbiology. - : Elsevier. - 0923-2508 .- 1769-7123. ; 170:6-7, s. 288-295
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Tidskriftsartikel (refereegranskat)abstract
- Due to land uplift after the last ice age, previously stable Baltic Sea sulfidic sediments are becoming dry land. When these sediments are drained, the sulfide minerals are exposed to air and can release large amounts of metals and acid into the environment. This can cause severe ecological damage such as fish kills in rivers feeding the northern Baltic Sea. In this study, five sites were investigated for the occurrence of acid sulfate soils and their geochemistry and microbiology was identified. The pH and soil chemistry identified three of the areas as having classical acid sulfate soil characteristics and culture independent identification of 16S rRNA genes identified populations related to acidophilic bacteria capable of catalyzing sulfidic mineral dissolution, including species likely adapted to low temperature. These results were compared to an acid sulfate soil area that had been flooded for ten years and showed that the previously oxidized sulfidic materials had an increased pH compared to the unremediated oxidizied layers. In addition, the microbiology of the flooded soil had changed such that alkalinity producing ferric and sulfate reducing reactions had likely occurred. This suggested that flooding of acid sulfate soils mitigates their environmental impact.
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| 2. |
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| 3. |
- Goncalves, Odete Sofia Lopes, et al.
(författare)
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The repeated 36 amino acid motif of Chlamydia trachomatis Hc2 protein binds to the major groove of DNA
- 2019
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Ingår i: Research in Microbiology. - : ELSEVIER. - 0923-2508 .- 1769-7123. ; 170:6-7, s. 256-262
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Tidskriftsartikel (refereegranskat)abstract
- The gram-negative, obligate intracellular human pathogen, Chlamydia trachomatis has a bi-phasic developmental cycle. The histone H1-like C. trachomatis DNA binding protein, Hc2, is produced late during the developmental cycle when the dividing reticulate body transforms into the smaller, metabolically inactive elementary body. Together with Hc1, the two proteins compact the chlamydial chromosome and arrest replication and transcription. Hc2 is heterogeneous in length due to variation in the number of lysine rich pentamers. Six pentamers and one hexamer constitute a 36 amino acid long repetitive unit that, in spite of variations, is unique for Chlamydiaceae. Using synthetic peptides, the DNA-binding capacity of the 36 amino acid peptide and that of a randomized peptide was analyzed. Both peptides bound and compacted plasmid DNA, however, electron microscopy of peptide/DNA complexes showed major differences in the resulting aggregated structures. Fluorescence spectroscopy was used to analyze the binding. After complexing plasmid DNA with each of three different intercalating dyes, increasing amounts of peptides were added and fluorescence spectroscopy performed. The major groove binder, methyl green, was displaced by both peptides at low concentrations, while the minor groove binder, Hoechts, and the intercalating dye, Ethidium Bromide, were displaced only at high concentrations of peptides. (C) 2019 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
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| 4. |
- Grones, Peter
(författare)
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Characterization of newly identified DnaA and DnaB proteins from Acetobacter
- 2016
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Ingår i: Research in Microbiology. - : Elsevier BV. - 0923-2508 .- 1769-7123. ; 167, s. 655-668
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Tidskriftsartikel (refereegranskat)abstract
- Although chromosomal replication is an essential feature of the bacterial life cycle, the replication mechanism and involved molecular players have never been properly characterized in the Acetobacter genera. Thanks to whole-genome sequencing, the unknown replication proteins from Acetobacter pasteurianus and Acetobacter orleanensis, DnaA-like and DnaB-like, could be identified. Despite the low nucleotide or amino acid similarity to the respective orthologs from Escherichia coli, their involvement during replication regulation was corroborated by artificial microRNA. In the Acetobacter genome, a novel replication origin, oriAo, was detected with three 9-nucleotide-long DnaA boxes to which DnaA-like proteins bind actively. Bacterial two-hybrid systems and co-immunoprecipitation confirmed the homologous and heterologous interactions between DnaA-like and DnaB-like proteins with their E. coli orthologs. This communication is due to the conserved tryptophan at position 6 for E. coli or 25 for Acetobacter that unables DnaA-like proteins to form oligomeric protein structures after its substitution. Altogether, these results provide novel insights into the genome replication mechanism in Acetobacter. (C) 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
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| 5. |
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| 6. |
- Ni, Gaofeng, et al.
(författare)
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Electricity generation from an inorganic sulfur compound containing mining wastewater by acidophilic microorganisms
- 2016
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Ingår i: Research in Microbiology. - : Elsevier BV. - 0923-2508 .- 1769-7123. ; 167:7, s. 568-575
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Tidskriftsartikel (refereegranskat)abstract
- Sulfide mineral processing often produces large quantities of wastewaters containing acid-generating inorganic sulfur compounds. If released untreated, these wastewaters can cause catastrophic environmental damage. In this study, microbial fuel cells were inoculated with acidophilic microorganisms to investigate whether inorganic sulfur compound oxidation can generate an electrical current. Cyclic voltammetry suggested that acidophilic microorganisms mediated electron transfer to the anode, and that electricity generation was catalyzed by microorganisms. A cation exchange membrane microbial fuel cell, fed with artificial wastewater containing tetrathionate as electron donor, reached a maximum whole cell voltage of 72 +/- 9 mV. Stepwise replacement of the artificial anolyte with real mining process wastewater had no adverse effect on bioelectrochemical performance and generated a maximum voltage of 105 +/- 42 mV. 16S rRNA gene sequencing of the microbial consortia resulted in sequences that aligned within the genera Thermoplasma, Ferroplasma, Leptospirillum, Sulfobacillus and Acidithiobacillus. This study opens up possibilities to bioremediate mining wastewater using microbial fuel cell technology. (C) 2016 The Authors. Published by Elsevier Masson SAS on behalf of Institut Pasteur.
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| 7. |
- Wittorf, Lea, et al.
(författare)
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Expression of nirK and nirS genes in two strains of Pseudomonas stutzeri harbouring both types of NO-forming nitrite reductases
- 2018
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Ingår i: Research in Microbiology. - : Elsevier BV. - 0923-2508 .- 1769-7123. ; 169, s. 343-347
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Tidskriftsartikel (refereegranskat)abstract
- Reduction of nitrite to nitric oxide in denitrification is catalysed by two different nitrite reductases, encoded by nirS or nirK. Long considered mutually exclusive and functionally redundant in denitrifying bacteria, we show expression of both genes co-occurring in Pseudomonas stutzeri. The differential expression patterns between strain AN10 and JM300 in relation to oxygen and nitrate and their different denitrification phenotypes, with AN10 reducing nitrate more rapidly and accumulating nitrite, suggest that nirS and nirK can have different roles. Dissimilar gene arrangements and transcription factors in the nir gene neighbourhoods could explain the observed differences in gene expression and denitrification activity. (C) 2018 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
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