scholarly journals Lineage-specific SoxR-mediated Regulation of an Endoribonuclease Protects Non-enteric Bacteria from Redox-active Compounds

2016 ◽  
Vol 292 (1) ◽  
pp. 121-133 ◽  
Author(s):  
Jisun Kim ◽  
Chulwoo Park ◽  
James A. Imlay ◽  
Woojun Park
Keyword(s):  
Enteric Bacteria ◽  
Active Compounds ◽  
Redox Active

scholarly journals Molecular Factors of Hypochlorite Tolerance in the Hypersaline Archaeon Haloferax volcanii

Genes ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 562 ◽  
Author(s):  
Miguel Gomez ◽  
Whinkie Leung ◽  
Swathi Dantuluri ◽  
Alexander Pillai ◽  
Zyan Gani ◽  
...  
Keyword(s):  
Hypochlorous Acid ◽  
Insertion Site ◽  
Model Organism ◽  
Halophilic Archaea ◽  
Haloferax Volcanii ◽  
Polyamine Biosynthesis ◽  
Active Compounds ◽  
Redox Active ◽  
High Concentrations ◽  
High Doses

Halophilic archaea thrive in hypersaline conditions associated with desiccation, ultraviolet (UV) irradiation and redox active compounds, and thus are naturally tolerant to a variety of stresses. Here, we identified mutations that promote enhanced tolerance of halophilic archaea to redox-active compounds using Haloferax volcanii as a model organism. The strains were isolated from a library of random transposon mutants for growth on high doses of sodium hypochlorite (NaOCl), an agent that forms hypochlorous acid (HOCl) and other redox acid compounds common to aqueous environments of high concentrations of chloride. The transposon insertion site in each of twenty isolated clones was mapped using the following: (i) inverse nested two-step PCR (INT-PCR) and (ii) semi-random two-step PCR (ST-PCR). Genes that were found to be disrupted in hypertolerant strains were associated with lysine deacetylation, proteasomes, transporters, polyamine biosynthesis, electron transfer, and other cellular processes. Further analysis revealed a ΔpsmA1 (α1) markerless deletion strain that produces only the α2 and β proteins of 20S proteasomes was hypertolerant to hypochlorite stress compared with wild type, which produces α1, α2, and β proteins. The results of this study provide new insights into archaeal tolerance of redox active compounds such as hypochlorite.

Influence of redox-active compounds and PXR-activators on human MRP1 and MRP2 gene expression

Toxicology ◽  
2002 ◽  
Vol 171 (2-3) ◽  
pp. 137-146 ◽  
Author(s):  
Hans-Martin Kauffmann ◽  
Sylvia Pfannschmidt ◽  
Heike Zöller ◽  
Anke Benz ◽  
Birgit Vorderstemann ◽  
...  
Keyword(s):  
Gene Expression ◽  
Active Compounds ◽  
Redox Active

Theoretical exploration of 2,2′-bipyridines as electro-active compounds in flow batteries

2019 ◽  
Vol 21 (28) ◽  
pp. 15823-15832 ◽  
Author(s):  
Mariano Sánchez-Castellanos ◽  
Martha M. Flores-Leonar ◽  
Zaahel Mata-Pinzón ◽  
Humberto G. Laguna ◽  
Karl M. García-Ruiz ◽  
...  
Keyword(s):  
Experimental Approach ◽  
Active Materials ◽  
Active Compounds ◽  
Redox Active ◽  
Flow Batteries

Identifying optimal 2,2′-bipyridine derivatives for negative redox-active materials in organic flow batteries using a combined theoretical and experimental approach.

scholarly journals Geothrix fermentans Secretes Two Different Redox-Active Compounds To Utilize Electron Acceptors across a Wide Range of Redox Potentials

2012 ◽  
Vol 78 (19) ◽  
pp. 6987-6995 ◽  
Author(s):  
Misha G. Mehta-Kolte ◽  
Daniel R. Bond
Keyword(s):  
Electron Transfer ◽  
Redox Potential ◽  
Electron Acceptor ◽  
Extracellular Electron Transfer ◽  
Redox Potentials ◽  
Active Compounds ◽  
Content Type ◽  
Electron Shuttles ◽  
Redox Active ◽  
Geothrix Fermentans

ABSTRACTThe current understanding of dissimilatory metal reduction is based primarily on isolates from the proteobacterial generaGeobacterandShewanella. However, environments undergoing active Fe(III) reduction often harbor less-well-studied phyla that are equally abundant. In this work, electrochemical techniques were used to analyze respiratory electron transfer by the only known Fe(III)-reducing representative of theAcidobacteria,Geothrix fermentans. In contrast to previously characterized metal-reducing bacteria, which typically reach maximal rates of respiration at electron acceptor potentials of 0 V versus standard hydrogen electrode (SHE),G. fermentansrequired potentials as high as 0.55 V to respire at its maximum rate. In addition,G. fermentanssecreted two different soluble redox-active electron shuttles with separate redox potentials (−0.2 V and 0.3 V). The compound with the lower midpoint potential, responsible for 20 to 30% of electron transfer activity, was riboflavin. The behavior of the higher-potential compound was consistent with hydrophilic UV-fluorescent molecules previously found inG. fermentanssupernatants. Both electron shuttles were also produced when cultures were grown with Fe(III), but not when fumarate was the electron acceptor. This study reveals thatGeothrixis able to take advantage of higher-redox-potential environments, demonstrates that secretion of flavin-based shuttles is not confined toShewanella, and points to the existence of high-potential-redox-active compounds involved in extracellular electron transfer. Based on differences between the respiratory strategies ofGeothrixandGeobacter, these two groups of bacteria could exist in distinctive environmental niches defined by redox potential.

scholarly journals Enhanced toxicity of aerosol in fog conditions in the Po Valley, Italy

2017 ◽  
Vol 17 (12) ◽  
pp. 7721-7731 ◽  
Author(s):  
Stefano Decesari ◽  
Mohammad Hossein Sowlat ◽  
Sina Hasheminassab ◽  
Silvia Sandrini ◽  
Stefania Gilardoni ◽  
...  
Keyword(s):  
Urban Areas ◽  
Water Soluble ◽  
Atmospheric Particulate Matter ◽  
Rural Site ◽  
Activity Data ◽  
Active Compounds ◽  
Fog Water ◽  
Po Valley ◽  
Redox Active ◽  
Airborne Concentration

Abstract. While numerous studies have demonstrated the association between outdoor exposure to atmospheric particulate matter (PM) and adverse health effects, the actual chemical species responsible for PM toxicological properties remain a subject of investigation. We provide here reactive oxygen species (ROS) activity data for PM samples collected at a rural site in the Po Valley, Italy, during the fog season (i.e., November–March). We show that the intrinsic ROS activity of Po Valley PM, which is mainly composed of biomass burning and secondary aerosols, is comparable to that of traffic-related particles in urban areas. The airborne concentration of PM components responsible for the ROS activity decreases in fog conditions, when water-soluble species are scavenged within the droplets. Due to this partitioning effect of fog, the measured ROS activity of fog water was contributed mainly by water-soluble organic carbon (WSOC) and secondary inorganic ions rather than by transition metals. We found that the intrinsic ROS activity of fog droplets is even greater (> 2.5 times) than that of the PM on which droplets are formed, indicating that redox-active compounds are not only scavenged from the particulate phase, but are also produced within the droplets. Therefore, even if fog formation exerts a scavenging effect on PM mass and redox-active compounds, the aqueous-phase formation of reactive secondary organic compounds can eventually enhance ROS activity of PM when fog evaporates. These findings, based on a case study during a field campaign in November 2015, indicate that a significant portion of airborne toxicity in the Po Valley is largely produced by environmental conditions (fog formation and fog processing) and not simply by the emission and transport of pollutants.

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