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Iron reducing bacteria

Elisa T Granato, Rolf Kümmerli
BACKGROUND: A common form of cooperation in bacteria is based on the secretion of beneficial metabolites, shareable as public good among cells within a group. Because cooperation can be exploited by "cheating" mutants, which contribute less or nothing to the public good, there has been great interest in understanding the conditions required for cooperation to remain evolutionarily stable. In contrast, much less is known about whether cheats, once fixed in the population, are able to revert back to cooperation when conditions change...
September 11, 2017: BMC Evolutionary Biology
Shiyang Li, Yi Cao, Cancan Bi, Yaobin Zhang
In this study, Fe(OH)3 was dosed into anaerobic reactor (R1) to stimulate the electron transfer process during the decoloration treatment. As results indicated, the chemical oxygen demand (COD) removal and decoloration efficiency were increased by 61.7% and 32.0% than that of the control reactor (R2), respectively. The cyclic-voltammetric analysis of the effluent demonstrated that the cycles of Fe(III)/Fe(II) and 1-imino-2-napthoquinone/1-amino-2-napthol (oxidative/reductive state of the decoloration intermediate product) had been established in R1...
August 13, 2017: Bioresource Technology
Weimin Sun, Enzong Xiao, Ziluo Pu, Valdis Krumins, Yiran Dong, Baoqin Li, Min Hu
Rice paddies are a significant source of the greenhouse gas methane, which mainly originates from microbial activity. Methane generation in anaerobic systems involves complex interactions of multiple functional microbial groups. Rice paddies installed in hilly terrain are often terraced, providing multiple quasi-independent plots differing primarily in their elevation up a hillside. This represents an excellent study site to explore the influence of environmental factors on microbial communities and interactions among microbial populations...
September 5, 2017: Science of the Total Environment
Patricia C Dos Santos
Complexes of iron and sulfur (Fe-S clusters) are widely distributed in nature and participate in essential biochemical reactions. The biological formation of Fe-S clusters involves dedicated pathways responsible for the mobilization of sulfur, the assembly of Fe-S clusters, and the transfer of these clusters to target proteins. Genomic analysis of Bacillus subtilis and other Gram-positive bacteria indicated the presence of only one Fe-S cluster biosynthesis pathway, which is distinct in number of components and organization from previously studied systems...
2017: Methods in Enzymology
Aura Ontiveros-Valencia, Chen Zhou, Zehra Esra Ilhan, Louis Cornette de Saint Cyr, Rosa Krajmalnik-Brown, Bruce E Rittmann
Molecular microbiology tools (i.e., 16S rDNA gene sequencing) were employed to elucidate changes in the microbial community structure according to the total electron acceptor loading (controlled by influent flow rate and/or medium composition) in a H2-based membrane biofilm reactor evaluated for removal of hexavalent uranium. Once nitrate, sulfate, and dissolved oxygen were replaced by U(VI) and bicarbonate and the total acceptor loading was lowered, slow-growing bacteria capable of reducing U(VI) to U(IV) dominated in the biofilm community: Replacing denitrifying bacteria Rhodocyclales and Burkholderiales were spore-producing Clostridiales and Natranaerobiales...
August 29, 2017: Water Research
Amanda D M Matos, Izabela C P Gomes, Silvia Nietsche, Adelica A Xavier, Wellington S Gomes, José A Dos Santos, Marlon C T Pereira
Forty isolates of endophytic bacteria isolated from banana tree roots were assessed as to their capacity to solubilize phosphate in a solid culture medium supplemented with different inorganic and one organic source of phosphorus. The amount of phosphorus (P) in each liquid medium was quantified, and an indirect assessment of acid phosphatase activity was performed. All assays had a fully randomized design, with three repetitions. Approximately 67.5% of the 40 isolates assessed in solid medium solubilized phosphorus from tricalcium phosphate and 7...
September 4, 2017: Anais da Academia Brasileira de Ciências
Shaomei He, Roman A Barco, David Emerson, Eric E Roden
Extracellular electron transfer (EET) is recognized as a key biochemical process in circumneutral pH Fe(II)-oxidizing bacteria (FeOB). In this study, we searched for candidate EET genes in 73 neutrophilic FeOB genomes, among which 43 genomes are complete or close-to-complete and the rest have estimated genome completeness ranging from 5 to 91%. These neutrophilic FeOB span members of the microaerophilic, anaerobic phototrophic, and anaerobic nitrate-reducing FeOB groups. We found that many microaerophilic and several anaerobic FeOB possess homologs of Cyc2, an outer membrane cytochrome c originally identified in Acidithiobacillus ferrooxidans...
2017: Frontiers in Microbiology
Nils Rädecker, Claudia Pogoreutz, Maren Ziegler, Ananya Ashok, Marcelle M Barreto, Veronica Chaidez, Carsten G B Grupstra, Yi Mei Ng, Gabriela Perna, Manuel Aranda, Christian R Voolstra
The productivity of coral reefs in oligotrophic tropical waters is sustained by an efficient uptake and recycling of nutrients. In reef-building corals, the engineers of these ecosystems, this nutrient recycling is facilitated by a constant exchange of nutrients between the animal host and endosymbiotic photosynthetic dinoflagellates (zooxanthellae), bacteria, and other microbes. Due to the complex interactions in this so-called coral holobiont, it has proven difficult to understand the environmental limitations of productivity in corals...
August 2017: Ecology and Evolution
Jean-Mathieu Leclerc, Charles M Dozois, France Daigle
Salmonella enterica serovars Typhi and Typhimurium are two closely related bacteria causing different types of infection in humans. Iron acquisition is considered essential for virulence. Siderophores are important iron chelators and production of enterobactin and salmochelins by these serovars was quantified. Overall, Salmonella Typhi produced higher levels of siderophores than Salmonella Typhimurium. The role of the global regulator Fur, involved in iron homeostasis, present and conserved in both these serovars, was then investigated...
August 15, 2017: FEMS Microbiology Letters
Jacob W McCabe, Rajpal Vangala, Laurence A Angel
Methanobactin (Mb) from Methylosinus trichosporium OB3b is a member of a class of metal binding peptides identified in methanotrophic bacteria. Mb will selectively bind and reduce Cu(II) to Cu(I), and is thought to mediate the acquisition of the copper cofactor for the enzyme methane monooxygenase. These copper chelating properties of Mb make it potentially useful as a chelating agent for treatment of diseases where copper plays a role including Wilson's disease, cancers, and neurodegenerative diseases. Utilizing traveling wave ion mobility-mass spectrometry (TWIMS), the competition for the Mb copper binding site from Ag(I), Pb(II), Co(II), Fe(II), Mn(II), Ni(II), and Zn(II) has been determined by a series of metal ion titrations, pH titrations, and metal ion displacement titrations...
August 30, 2017: Journal of the American Society for Mass Spectrometry
Zheyun Zhang, Hee Sun Moon, Satish C B Myneni, Peter R Jaffé
Although abiotic process of competitive sorption between phosphate (P) and arsenate (As(V)), especially onto iron oxides, are well understood, P-mediated biotic processes of Fe and As redox transformation contributing to As mobilization and speciation in wetlands remain poorly defined. To gain new insights into the effects of P on As mobility, speciation, and bioavailability in wetlands, well-controlled greenhouse experiments were conducted. As expected, increased P levels contributed to more As desorption, but more interestingly the interactions between P and wetland plants played a synergistic role in the microbially-mediated As mobilization and enhanced As uptake by plants...
August 21, 2017: Chemosphere
Sunita J Varjani, Edgard Gnansounou
Petroleum is produced by thermal decay of buried organic material over millions of years. Petroleum oilfield ecosystems represent resource of reduced carbon which favours microbial growth. Therefore, it is obvious that many microorganisms have adapted to harsh environmental conditions of these ecosystems specifically temperature, oxygen availability and pressure. Knowledge of microorganisms present in ecosystems of petroleum oil reservoirs; their physiological and biological properties help in successful exploration of petroleum...
August 9, 2017: Bioresource Technology
Ali M Bazzi, Jaffar A Al-Tawfiq, Ali A Rabaan
INTRODUCTION: Acinetobacter baumannii and Brucella species are Gram-negative organisms that are vulnerable to misinterpretation as Gram-positive or Gram-variable in blood cultures. OBJECTIVE: We assess the random errors in gram stain interpretation to reduce the likelihood of such errors and therefore patient harm. METHODOLOGY: Aerobic and anaerobic blood cultures from two patients in an acute care facility in Saudi Arabia were subjected to preliminary Gram-staining...
2017: Open Microbiology Journal
Liang Tao, Zhen-Ke Zhu, Fang-Bai Li, Shan-Li Wang
Copper is a trace element essential for living creatures, but copper content in soil should be controlled, as it is toxic. The physical-chemical-biological features of Cu in soil have a significant correlation with the Fe(II)/Cu(II) interaction in soil. Of significant interest to the current study is the effect of Fe(II)/Cu(II) interaction conducted on goethite under anaerobic conditions stimulated by HS01 (a dissimilatory iron reduction (DIR) microbial). The following four treatments were designed: HS01 with α-FeOOH and Cu(II) (T1), HS01 with α-FeOOH (T2), HS01 with Cu(II) (T3), and α-FeOOH with Cu(II) (T4)...
August 16, 2017: Chemosphere
A Jdey, H Falleh, S Ben Jannet, K Mkadmini Hammi, X Dauvergne, C Magné, R Ksouri
Six medicinal halophytes widely represented in North Africa and commonly used in traditional medicine were screened for pharmacological properties to set out new promising sources of natural ingredients for cosmetic or nutraceutical applications. Thus, Citrullus colocynthis, Cleome arabica, Daemia cordata, Haloxylon articulatum, Pituranthos scoparius and Scorzonera undulata were examined for their in vitro antioxidant (DPPH scavenging and superoxide anion-scavenging, β-carotene bleaching inhibition and iron-reducing tests), antibacterial (microdilution method, against four human pathogenic bacteria) and anti-tyrosinase activities...
2017: EXCLI journal
Bangjing Ding, Zhengkui Li, Yunbin Qin
Anaerobic ammonium oxidation coupled to iron(III) reduction (termed Feammox) is a recently discovered pathway of nitrogen cycling. However, little is known about the pathways of N transformation via Feammox process in riparian zones. In this study, evidence for Feammox in riparian zones with or without vegetation cover was demonstrated using isotope tracing technique and high-throughput sequencing technology. The results showed that Feammox could occur in riparian zones, and demonstrated that N2 directly from Feammox was dominant Feammox pathway...
August 14, 2017: Environmental Pollution
Tim Kamber, Joël F Pothier, Cosima Pelludat, Fabio Rezzonico, Brion Duffy, Theo H M Smits
BACKGROUND: Type VI secretion systems (T6SS) are widespread among Gram-negative bacteria and have a potential role as essential virulence factors or to maintain symbiotic interactions. Three T6SS gene clusters were identified in the genome of E. amylovora CFBP 1430, of which T6SS-1 and T6SS-3 represent complete T6SS machineries, while T6SS-2 is reduced in its gene content. RESULTS: To assess the contribution of T6SSs to virulence and potential transcriptomic changes of E...
August 17, 2017: BMC Genomics
Jana Jencarova, Alena Luptakova, Nikola Vitkovska, Dalibor Matysek, Petr Jandacka
Biomineralization means mineral formation under the influence of organisms. Sulphate-reducing bacteria (SRB) constitute an essential role of iron sulphide minerals precipitation. Their composition involves amorphous, non-stoichiometric or crystalline iron sulphides, weakly or strongly magnetic. Variation in environmental conditions can alter the reactive iron species within the mineral, potentially modifying their magnetic properties. Biogenic iron sulphide minerals can be used as heavy metals and toxic ions adsorbents in soil or water remediation...
August 18, 2017: Environmental Technology
Qian Wu, Yuanyuan Shen, Yunlong Tao, Jiayu Wei, Hao Wang, Peng An, Zhuzhen Zhang, Hong Gao, Tianhua Zhou, Fudi Wang, Junxia Min
Hereditary hemochromatosis and iron imbalance are associated with susceptibility to bacterial infection; however, the underlying mechanisms are poorly understood. Here, we performed in vivo bacterial infection screening using several mouse models of hemochromatosis, including Hfe (Hfe(-/-) ), hemojuvelin (Hjv(-/-) ), and macrophage-specific ferroportin-1 (Fpn1(fl/fl) ;LysM-Cre(+) ) knockout mice. We found that Hjv(-/-) mice, but not Hfe(-/-) or Fpn1(fl/fl) ;LysM-Cre(+) mice, are highly susceptible to peritoneal infection by both Gram-negative and Gram-positive bacteria...
2017: Cell Discovery
Wei-Ting Lee, Ya-Na Wu, Yi-Hsuan Chen, Shang-Rung Wu, Tsai-Miao Shih, Tsung-Ju Li, Li-Xing Yang, Chen-Sheng Yeh, Pei-Jane Tsai, Dar-Bin Shieh
Clinical management of Clostridium difficile infection is still far from satisfactory as bacterial spores are resistant to many chemical agents and physical treatments. Certain types of nanoparticles have been demonstrated to exhibit anti-microbial efficacy even in multi-drug resistance bacteria. However, most of these studies failed to show biocompatibility to the mammalian host cells and no study has revealed in vivo efficacy in C. difficile infection animal models. The spores treated with 500 µg/mL Fe3-δO4 nanoparticles for 20 minutes, 64% of the spores were inhibited from transforming into vegetative cells, which was close to the results of the sodium hypochlorite-treated positive control...
August 15, 2017: Scientific Reports
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