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Iron reducing bacteria

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https://www.readbyqxmd.com/read/28533366/mechanism-of-h2s-mediated-protection-against-oxidative-stress-in-escherichia-coli
#1
Alexander Mironov, Tatyana Seregina, Maxim Nagornykh, Lyly G Luhachack, Natalya Korolkova, Liubov Errais Lopes, Vera Kotova, Gennady Zavilgelsky, Rustem Shakulov, Konstantin Shatalin, Evgeny Nudler
Endogenous hydrogen sulfide (H2S) renders bacteria highly resistant to oxidative stress, but its mechanism remains poorly understood. Here, we report that 3-mercaptopyruvate sulfurtransferase (3MST) is the major source of endogenous H2S in Escherichia coli Cellular resistance to H2O2 strongly depends on the activity of mstA, a gene that encodes 3MST. Deletion of the ferric uptake regulator (Fur) renders ∆mstA cells hypersensitive to H2O2 Conversely, induction of chromosomal mstA from a strong pLtetO-1 promoter (P tet -mstA) renders ∆fur cells fully resistant to H2O2 Furthermore, the endogenous level of H2S is reduced in ∆fur or ∆sodA ∆sodB cells but restored after the addition of an iron chelator dipyridyl...
May 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28512090/the-vibrio-cholerae-vexgh-rnd-efflux-system-maintains-cellular-homeostasis-by-effluxing-vibriobactin
#2
Dillon E Kunkle, X Renee Bina, James E Bina
Resistance-nodulation-division (RND) superfamily efflux systems have been widely studied for their role in antibiotic resistance, but their native biological functions remain poorly understood. We previously showed that loss of RND-mediated efflux in Vibrio cholerae resulted in activation of the Cpx two-component regulatory system, which mediates adaptation to stress resulting from misfolded membrane proteins. Here, we investigated the mechanism linking RND-mediated efflux to the Cpx response. We performed transposon mutagenesis screening of RND-deficient V...
May 16, 2017: MBio
https://www.readbyqxmd.com/read/28487680/diversity-of-metabolically-active-bacteria-in-water-flooded-high-temperature-heavy-oil-reservoir
#3
Tamara N Nazina, Natalya M Shestakova, Ekaterina M Semenova, Alena V Korshunova, Nadezda K Kostrukova, Tatiana P Tourova, Liu Min, Qingxian Feng, Andrey B Poltaraus
The goal of this work was to study the overall genomic diversity of microorganisms of the Dagang high-temperature oilfield (PRC) and to characterize the metabolically active fraction of these populations. At this water-flooded oilfield, the microbial community of formation water from the near-bottom zone of an injection well where the most active microbial processes of oil degradation occur was investigated using molecular, cultural, radiotracer, and physicochemical techniques. The samples of microbial DNA and RNA from back-flushed water were used to obtain the clone libraries for the 16S rRNA gene and cDNA of 16S rRNA, respectively...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28475687/the-quinoline-bromoquinol-exhibits-broad-spectrum-antifungal-activity-and-induces-oxidative-stress-and-apoptosis-in-aspergillus-fumigatus
#4
Dafna Ben Yaakov, Yana Shadkchan, Nathaniel Albert, Dimitrios P Kontoyiannis, Nir Osherov
Objectives: Over the last 30 years, the number of invasive fungal infections among immunosuppressed patients has increased significantly, while the number of effective systemic antifungal drugs remains low. The aim of this study was to identify and characterize antifungal compounds that inhibit fungus-specific metabolic pathways not conserved in humans. Methods: We screened a diverse compound library for antifungal activity in the pathogenic mould Aspergillus fumigatus ...
May 5, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/28470848/iron-catalysis-at-the-origin-of-life
#5
Eloi Camprubi, Sean F Jordan, Rafaela Vasiliadou, Nick Lane
Iron-sulphur proteins are ancient and drive fundamental processes in cells, notably electron transfer and CO2 fixation. Iron-sulphur minerals with equivalent structures could have played a key role in the origin of life. However, the 'iron-sulphur world' hypothesis has had a mixed reception, with questions raised especially about the feasibility of a pyrites-pulled reverse Krebs cycle. Phylogenetics suggests that the earliest cells drove carbon and energy metabolism via the acetyl CoA pathway, which is also replete in Fe(Ni)S proteins...
May 3, 2017: IUBMB Life
https://www.readbyqxmd.com/read/28463500/iruo-uses-an-fad-semiquinone-intermediate-for-iron-siderophore-reduction
#6
Marek J Kobylarz, Graham A Heieis, Slade A Loutet, Michael E P Murphy
Many pathogenic bacteria including Staphylococcus aureus use iron-chelating siderophores to acquire iron. IruO, an FAD-containing NADPH-dependent reductase from S. aureus, functions as a reductase for IsdG and IsdI, two paralogous heme degrading enzymes. Also, the gene encoding for IruO was shown to be required for growth of S. aureus on hydroxamate siderophores as a sole iron source. Here, we show that IruO binds the hydroxamate-type siderophores desferrioxamine B and ferrichrome A with low micromolar affinity and in the presence of NADPH, Fe(II) was released...
May 2, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28454040/the-role-of-dissimilatory-arsenate-reducing-bacteria-in-the-biogeochemical-cycle-of-arsenic-based-on-the-physiological-and-functional-analysis-of-aeromonas-sp-o23a
#7
Witold Uhrynowski, Klaudia Debiec, Aleksandra Sklodowska, Lukasz Drewniak
Dissimilatory arsenate reducing bacteria (DARB) are known to contribute to the mobilization of arsenic and other elements from minerals. Despite this, metabolic capabilities of only a few DARB strains have been thoroughly investigated so far, and the influence of these bacteria on the bioavailability of arsenic in the environment is still a topic for discussion. In this study, Aeromonas sp. O23A, one of the dominant DARB strains found in the Zloty Stok mine (SW Poland), was subjected to a detailed physiological and functional analysis aimed to identify the actual environmental impact of this strain...
April 25, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28445245/ectopic-expression-of-innate-immune-protein-lipocalin-2-in-lactococcus-lactis-protects-against-gut-and-environmental-stressors
#8
Piu Saha, Benoit Chassaing, Beng San Yeoh, Emilie Viennois, Xia Xiao, Mary J Kennett, Vishal Singh, Matam Vijay-Kumar
BACKGROUND: Lipocalin-2 (Lcn2) is a multifunctional innate immune protein that exhibits antimicrobial activity by the sequestration of bacterial siderophores, regulates iron homeostasis, and augments cellular tolerance to oxidative stress. Studies in the murine model of colitis have demonstrated that Lcn2 deficiency exacerbates colitogenesis; however, the therapeutic potential of Lcn2 supplementation has yet to be elucidated. In light of its potential mucoprotective functions, we, herein, investigated whether expression of Lcn2 in the probiotic bacterium can be exploited to alleviate experimental colitis...
April 25, 2017: Inflammatory Bowel Diseases
https://www.readbyqxmd.com/read/28443246/genetic-and-dietary-iron-overload-differentially-affect-the-course-of-salmonella-typhimurium-infection
#9
Manfred Nairz, Andrea Schroll, David Haschka, Stefanie Dichtl, Piotr Tymoszuk, Egon Demetz, Patrizia Moser, Hubertus Haas, Ferric C Fang, Igor Theurl, Günter Weiss
Genetic and dietary forms of iron overload have distinctive clinical and pathophysiological features. HFE-associated hereditary hemochromatosis is characterized by overwhelming intestinal iron absorption, parenchymal iron deposition, and macrophage iron depletion. In contrast, excessive dietary iron intake results in iron deposition in macrophages. However, the functional consequences of genetic and dietary iron overload for the control of microbes are incompletely understood. Using Hfe(+/+) and Hfe(-/-) mice in combination with oral iron overload in a model of Salmonella enterica serovar Typhimurium infection, we found animals of either genotype to induce hepcidin antimicrobial peptide expression and hypoferremia following systemic infection in an Hfe-independent manner...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28440618/design-of-antibacterial-poly-ether-sulfone-membranes-via-covalently-attaching-hydrogel-thin-layers-loaded-with-ag-nanoparticles
#10
Min He, Qian Wang, Rui Wang, Yi Xie, Weifeng Zhao, Changsheng Zhao
To inhibit bacteria attachment and the subsequent formation of biofilms on poly(ether sulfone) (PES) membranes, poly(sulfobetaine methacrylate)/poly(sodium acrylate) antibacterial hydrogel thin layers were covalently attached onto the membranes, followed by loading with Ag nanoparticles. In our strategy, double bonds were firstly introduced onto the PES membrane surfaces to provide anchoring sites, and then the hydrogel layers were synthesized on the membrane surfaces via UV light-initiated crosslinking copolymerization...
May 3, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28428774/biochar-addition-increases-the-rates-of-dissimilatory-iron-reduction-and-methanogenesis-in-ferrihydrite-enrichments
#11
Guo-Wei Zhou, Xiao-Ru Yang, Christopher W Marshall, Hu Li, Bang-Xiao Zheng, Yu Yan, Jian-Qiang Su, Yong-Guan Zhu
Biochar contains quinones and aromatic structures that facilitate extracellular electron transfer between microbial cells and insoluble minerals. In this study, granulated biochar (1.2-2 mm) and powdered biochar (<0.15 mm) were amended to two ferrihydrite (in situ ferrihydrite and ex situ ferrihydrite) enrichments to investigate the effect of biochar with different particle sizes on dissimilatory iron(III)-reducing bacteria (DIRB) and methanogens. Biochar addition significantly stimulated the reduction of both in situ ferrihydrite and ex situ ferrihydrite and the production of methane...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28402894/reductive-dechlorination-of-carbon-tetrachloride-by-bioreduction-of-nontronite
#12
Sungjun Bae, Ji Bong Joo, Woojin Lee
Reductive dechlorination of carbon tetrachloride (CT) was investigated during bioreduction of iron-containing clay mineral (i.e., nontronite) by iron-reducing bacteria (Shewanella putrefaciens CN32 (CN32)). In the absence of CT, the production of Fe(II) significantly increased in nontronite suspension with CN32 in 124 d (11.1% of Fe(III) reduction), resulting in formation of new secondary Fe(II) mineral phase (i.e., vivianite (Fe(II)3(PO4)2·8H2O)). In the presence of CT, an acceleration of CT dechlorination was observed after 13 d and it reached almost 68% of removal efficiency at 32 d in nontronite suspension with CN32, which was 1...
April 1, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28402041/inactivation-of-ferric-uptake-regulator-fur-attenuates-helicobacter-pylori-j99-motility-by-disturbing-the-flagellar-motor-switch-and-autoinducer-2-production
#13
Ai-Yun Lee, Cheng-Yen Kao, Yao-Kuan Wang, Ssu-Yuan Lin, Tze-Ying Lai, Bor-Shyang Sheu, Chien-Jung Lo, Jiunn-Jong Wu
BACKGROUND: Flagellar motility of Helicobacter pylori has been shown to be important for the bacteria to establish initial colonization. The ferric uptake regulator (Fur) is a global regulator that has been identified in H. pylori which is involved in the processes of iron uptake and establishing colonization. However, the role of Fur in H. pylori motility is still unclear. MATERIALS AND METHODS: Motility of the wild-type, fur mutant, and fur revertant J99 were determined by a soft-agar motility assay and direct video observation...
April 12, 2017: Helicobacter
https://www.readbyqxmd.com/read/28401391/temporal-abundance-and-activity-trends-of-vinyl-chloride-vc-degrading-bacteria-in-a-dilute-vc-plume-at-naval-air-station-oceana
#14
Yi Liang, Laura J Cook, Timothy E Mattes
Assessment and monitoring of microbial community dynamics is useful when tracking the progress of vinyl chloride (VC) bioremediation strategies, particularly in dilute plumes where apparent VC attenuation rates are low. In a long-term field study, the abundance and the activity of microbial VC degraders were tracked in three monitoring wells (MW05, MW25, and MW19) along a dilute VC plume at Naval Air Station (NAS) Oceana. High-throughput sequencing of partial 16S ribosomal RNA (rRNA) genes and transcripts revealed diverse groundwater microbial communities and showed that methanotrophs and anaerobic respirers (e...
April 11, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28396543/a-topical-hydrogel-with-deferiprone-and-gallium-protoporphyrin-targets-bacterial-iron-metabolism-and-has-antibiofilm-activity
#15
Katharina Richter, Nicky Thomas, Jolien Claeys, Jonathan McGuane, Clive A Prestidge, Tom Coenye, Peter-John Wormald, Sarah Vreugde
Many infectious diseases are associated with multidrug-resistant (MDR) bacteria residing in biofilms that require high antibiotic concentrations. Whilst oral drug-delivery is frequently ineffective, topical treatments have the potential to deliver higher drug concentrations to the infection-site while reducing systemic side-effects.This study determined the antibiofilm activity of a surgical wound-gel loaded with the iron-chelator deferiprone (Def) and the heme-analogue gallium-protoporphyrin (GaPP), alone and in combination with ciprofloxacin...
April 10, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28382330/metatranscriptomics-supports-the-mechanism-for-biocathode-electroautotrophy-by-candidatus-tenderia-electrophaga
#16
Brian J Eddie, Zheng Wang, W Judson Hervey, Dagmar H Leary, Anthony P Malanoski, Leonard M Tender, Baochuan Lin, Sarah M Strycharz-Glaven
Biocathodes provide a stable electron source to drive reduction reactions in electrotrophic microbial electrochemical systems. Electroautotrophic biocathode communities may be more robust than monocultures in environmentally relevant settings, but some members are not easily cultivated outside the electrode environment. We previously used metagenomics and metaproteomics to propose a pathway for coupling extracellular electron transfer (EET) to carbon fixation in "Candidatus Tenderia electrophaga," an uncultivated but dominant member of an electroautotrophic biocathode community...
March 2017: MSystems
https://www.readbyqxmd.com/read/28377745/photoferrotrophy-remains-of-an-ancient-photosynthesis-in-modern-environments
#17
REVIEW
Antonio Camacho, Xavier A Walter, Antonio Picazo, Jakob Zopfi
Photoferrotrophy, the process by which inorganic carbon is fixed into organic matter using light as an energy source and reduced iron [Fe(II)] as an electron donor, has been proposed as one of the oldest photoautotrophic metabolisms on Earth. Under the iron-rich (ferruginous) but sulfide poor conditions dominating the Archean ocean, this type of metabolism could have accounted for most of the primary production in the photic zone. Here we review the current knowledge of biogeochemical, microbial and phylogenetic aspects of photoferrotrophy, and evaluate the ecological significance of this process in ancient and modern environments...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28373869/the-role-of-enriched-microbial-consortium-on-iron-reducing-bioaugmentation-in-sediments
#18
Yuanyuan Pan, Xunan Yang, Meiying Xu, Guoping Sun
Microbial iron reduction is an important biogeochemical process and involved in various engineered processes, including the traditional clay dyeing processes. Bioaugmentation with iron reducing bacteria (IRB) is generally considered as an effective method to enhance the activity of iron reduction. However, limited information is available about the role of IRB on bioaugmentation. To reveal the roles of introduced IRB on bioaugmentation, an IRB consortium enriched with ferric citrate was inoculated into three Fe(II)-poor sediments which served as the pigments for Gambiered Guangdong silk dyeing...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28348025/vibrio-cholerae-vcib-mediates-iron-reduction
#19
Eric D Peng, Shelley M Payne
Vibrio cholerae is the causative agent of the severe diarrheal disease cholera. V. cholerae thrives within the human host where it replicates to high numbers but also persists within the aquatic environments of ocean and brackish water. To survive within these nutritionally diverse environments, V. cholerae must encode the necessary tools to acquire the essential nutrient iron in all forms it may encounter. A prior study of systems involved in iron transport in V. cholerae revealed the existence of vciB which, while unable to directly transport iron, stimulates the transport of iron through ferrous (Fe(2+)) iron transport systems...
March 27, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28317737/identification-of-the-key-excreted-molecule-by-lactobacillus-fermentum-related-to-host-iron-absorption
#20
Ana González, Natividad Gálvez, Jesús Martín, Fernando Reyes, Ignacio Pérez-Victoria, Jose M Dominguez-Vera
We have taken a vital step towards understanding why probiotic bacteria increase iron absorption in the gastrointestinal tract. We show here that Lactobacillus fermentum, one of the main probiotics of the microbiota, exhibits an extraordinary ferric-reducing activity. This activity is predominantly due to an excreted molecule: p-hydroxyphenyllactic acid (HPLA). Reduction of Fe(III) to Fe(II) is essential for iron absorption in the gastrointestinal tract. By reducing Fe(III), HPLA boosts Fe(II) absorption through the DMT1 channels of enterocytes...
August 1, 2017: Food Chemistry
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