Anaerobic Respiration of Elemental Sulfur and Thiosulfate by
 Shewanella oneidensis
 MR-1 Requires
 psrA
 , a Homolog of the
 phsA
 Gene of
 Salmonella enterica
 Serovar Typhimurium LT2

Burns, Justin L.; DiChristina, Thomas J.

doi:10.1128/aem.00888-09

Cited by 126 publications

(110 citation statements)

References 61 publications

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“…S. oneidensis is able to produce H 2 S through both cysteine degradation and respiration of sulfur species (13)(14)(15). Under aerobic conditions, H 2 S produced through respiration is negligible, especially when the relevant sulfur species is not added (15).…”

Section: Resultsmentioning

confidence: 99%

“…There is endogenous H 2 S generation in S. oneidensis (12), but not until recently was its enzymatic foundation determined (13)(14)(15). Through anaerobic respiration of inorganic sulfur compounds in the periplasm, including thiosulfate (S 2 O 3 2Ϫ ), sulfite (SO 3 2Ϫ ), tetrathionate (S 4 O 6 2Ϫ ), and elemental sulfur (S 0 ), S. oneidensis generates H 2 S with sulfite reductase SirACD, as well as thiosulfate and polysulfide reductase PsrABC (13,14,16). Cysteine degradation via methionine ␥-lyase MdeA is the predominant source of endogenous H 2 S production, with other mechanisms via SO_1095 and SseA being of lesser importance (15).…”

mentioning

confidence: 99%

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A Matter of Timing: Contrasting Effects of Hydrogen Sulfide on Oxidative Stress Response in Shewanella oneidensis

Wan

et al. 2015

J Bacteriol

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Hydrogen sulfide (H 2 S), well known for its toxic properties, has recently become a research focus in bacteria, in part because it has been found to prevent oxidative stress caused by treatment with some antibiotics. H 2 S has the ability to scavenge reactive oxygen species (ROS), thus preventing oxidative stress, but it is also toxic, leading to conflicting reports of its effects in different organisms. Here, with Shewanella oneidensis as a model, we report that the effects of H 2 S on the response to oxidative stress are time dependent. When added simultaneously with H 2 O 2 , H 2 S promoted H 2 O 2 toxicity by inactivating catalase, KatB, a hemecontaining enzyme involved in H 2 O 2 degradation. Such an inhibitory effect may apply to other heme-containing proteins, such as cytochrome cbb 3 oxidase. When H 2 O 2 was supplied 20 min or later after the addition of H 2 S, the oxidative-stress-responding regulator OxyR was activated, resulting in increased resistance to H 2 O 2 . The activation of OxyR was likely triggered by the influx of iron, a response to lowered intracellular iron due to the iron-sequestering property of H 2 S. Given that Shewanella bacteria thrive in redox-stratified environments that have abundant sulfur and iron species, our results imply that H 2 S is more important for bacterial survival in such environmental niches than previously believed. IMPORTANCE Previous studies have demonstrated that H 2 S is either detrimental or beneficial to bacterial cells. While it can act as a growth-inhibiting molecule by damaging DNA and denaturing proteins, it helps cells to combat oxidative stress. Here we report that H 2 S indeed has these contrasting biological functions and that its effects are time dependent. Immediately after H 2 S treatment, there is growth inhibition due to damage of heme-containing proteins, at least to catalase and cytochrome c oxidase. In contrast, when added a certain time later, H 2 S confers an enhanced ability to combat oxidative stress by activating the H 2 O 2 -responding regulator OxyR. Our data reconcile conflicting observations about the functions of H 2 S.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

A Matter of Timing: Contrasting Effects of Hydrogen Sulfide on Oxidative Stress Response in Shewanella oneidensis

Wan

et al. 2015

J Bacteriol

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“…Shewanella oneidensis can use a diversity of terminal electron acceptors. In the absence of O 2 , these acceptors include fumarate, nitrate, trimethylamine oxide (TMAO), dimethyl sulfoxide (DMSO), sulfite, thiosulfate, elemental sulfur and oxidized metals such as Fe(III), Mn(III), Mn(IV) and U(VI) that may be present either as soluble complexes or within solid mineral (hydr)oxides [29][30][31][32][33]. This respiratory versatility makes S. oneidensis competitive in complex aquatic and sedimentary systems.…”

Section: Overview Of Multi-haem Cytochromes In the Metabolism Of Shewmentioning

confidence: 99%

Multi-haem cytochromes inShewanella oneidensisMR-1: structures, functions and opportunities

Breuer

Rosso

Blumberger

et al. 2015

J. R. Soc. Interface.

218

186

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Multi-haem cytochromes are employed by a range of microorganisms to transport electrons over distances of up to tens of nanometres. Perhaps the most spectacular utilization of these proteins is in the reduction of extracellular solid substrates, including electrodes and insoluble mineral oxides of Fe(III) and Mn(III/IV), by species of Shewanella and Geobacter. However, multihaem cytochromes are found in numerous and phylogenetically diverse prokaryotes where they participate in electron transfer and redox catalysis that contributes to biogeochemical cycling of N, S and Fe on the global scale. These properties of multi-haem cytochromes have attracted much interest and contributed to advances in bioenergy applications and bioremediation of contaminated soils. Looking forward, there are opportunities to engage multi-haem cytochromes for biological photovoltaic cells, microbial electrosynthesis and developing bespoke molecular devices. As a consequence, it is timely to review our present understanding of these proteins and we do this here with a focus on the multitude of functionally diverse multi-haem cytochromes in Shewanella oneidensis MR-1. We draw on findings from experimental and computational approaches which ideally complement each other in the study of these systems: computational methods can interpret experimentally determined properties in terms of molecular structure to cast light on the relation between structure and function. We show how this synergy has contributed to our understanding of multi-haem cytochromes and can be expected to continue to do so for greater insight into natural processes and their informed exploitation in biotechnologies.

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“…By analyzing the genomes of 15 Shewanella strains, Zhao et al (2010) observed that the RDX-degrading strains had a higher number of genes for cytochromes and nitrate or nitrite reductases. The iron-reducing bacterium Shewanella oneidensis MR-1 (Myers and Nealson 1988) has a complex electron transfer network and can utilize a variety of electron acceptors for anaerobic respiration, including Fe(III), Mn(IV), fumarate, nitrate, TMAO, and a variety of metals (Nealson and Saffarini 1994;Burns and DiChristina 2009). Because of its exceptional metabolic versatility and its potential use for the bioremediation of environmental contaminants, MR-1 has been extensively studied and its genome has been sequenced (Heidelberg et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Involvement of cytochrome c CymA in the anaerobic metabolism of RDX by Shewanella oneidensis MR-1

et al. 2012

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Involvement of cytochrome c cymA in the anaerobic metabolism of RDX by shewanella oneidensis MR-1 Perreault, Nancy N.; Crocker, Fiona H.; Indest, Karl J.; Hawari, Jalal Involvement of cytochrome c CymA in the anaerobic metabolism of RDX by Shewanella oneidensis MR-1 Nancy N. Perreault, Fiona H. Crocker, Karl J. Indest, and Jalal Hawari Abstract: Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a cyclic nitramine explosive commonly used for military applications that is responsible for severe soil and groundwater contamination. In this study, Shewanella oneidensis MR-1 was shown to efficiently degrade RDX anaerobically (3.5 µmol·h -1 ·(g protein) -1 ) via two initial routes: (1) sequential N-NO2 reductions to the corresponding nitroso (N-NO) derivatives (94% of initial RDX degradation) and (2) denitration followed by ring cleavage. To identify genes involved in the anaerobic metabolism of RDX, a library of~2500 mutants of MR-1 was constructed by random transposon mutagenesis and screened for mutants with a reduced ability to degrade RDX compared with the wild type. An RDX-defective mutant (C9) was isolated that had the transposon inserted in the c-type cytochrome gene cymA. C9 transformed RDX at~10% of the wild-type rate, with degradation occurring mostly via early ring cleavage caused by initial denitration leading to the formation of methylenedinitramine, 4-nitro-2,4-diazabutanal, formaldehyde, nitrous oxide, and ammonia. Genetic complementation of mutant C9 restored the wild-type phenotype, providing evidence that electron transport components have a role in the anaerobic reduction of RDX by MR-1.Key words: RDX, explosive, nitramine, biotransformation, Shewanella.Résumé : La nitramine cyclique hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) est un explosif couramment utilisé pour des applications militaires et qui cause une contamination sévère de sols et eaux souterraines. Shewanella oneidensis MR-1 a dé-gradé efficacement le RDX en condition anaérobique (3,5 µmol·h -1 ·(g protéine) -1 ) via deux routes initiales : (1) la réduction séquentielle du N-NO2 en dérivés nitroso correspondants (N-NO) (94 % de la dégradation initiale du RDX); (2) dénitration suivie du clivage de l'anneau du RDX. Afin d'identifier des gènes impliqués dans le métabolisme anaérobique du RDX, une banque d'environ 2500 mutants MR-1 fut construite par mutagenèse aléatoire par transposition et criblée à la recherche de mutants présentant une diminution de l'activité de dégradation du RDX par rapport à la souche sauvage. Un mutant (C9) fut isolé avec un transposon inséré dans le gène du cytochrome c cymA. C9 transformait le RDX à~10 % du taux de dégra-dation de la souche sauvage. La dégradation s'effectuait principalement par dénitration suivie du clivage de l'anneau et conduisait à la formation de méthylènedinitramine, 4-nitro-2,4-diazabutanal, formaldéhyde, oxyde nitreux et ammoniac. La complémentation génétique du mutant C9 a permis de restaurer le phénotype sauvage et d'ainsi confirmer que des composants de la chaîne de transport d'électro...

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Anaerobic Respiration of Elemental Sulfur and Thiosulfate by Shewanella oneidensis MR-1 Requires psrA , a Homolog of the phsA Gene of Salmonella enterica Serovar Typhimurium LT2

Cited by 126 publications

References 61 publications

A Matter of Timing: Contrasting Effects of Hydrogen Sulfide on Oxidative Stress Response in Shewanella oneidensis

A Matter of Timing: Contrasting Effects of Hydrogen Sulfide on Oxidative Stress Response in Shewanella oneidensis

Multi-haem cytochromes inShewanella oneidensisMR-1: structures, functions and opportunities

Involvement of cytochrome c CymA in the anaerobic metabolism of RDX by Shewanella oneidensis MR-1

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