Anaerobic Respiration on Nitarsone in Aquatic Environments by Shewanella oneidensis MR-1 Lacking Known C·As lyases

ABSTRACT Vibrio natriegens is the fastest-growing microorganism discovered to date, making it a useful model for biotechnology and basic research. While it is recognized for its rapid aerobic metabolism, less is known about anaerobic adaptations in V. natriegens or how the organism survives when oxygen is limited. Here, we describe and characterize extracellular electron transfer (EET) in V. natriegens, a metabolism that requires movement of electrons across protective cellular barriers to reach the extracellular space. V. natriegens performs extracellular electron transfer under fermentative conditions with gluconate, glucosamine, and pyruvate. We characterized a pathway in V. natriegens that requires CymA, PdsA, and MtrCAB for Fe(III) citrate and Fe(III) oxide reduction, which represents a hybrid of strategies previously discovered in Shewanella and Aeromonas. Expression of these V. natriegens genes functionally complemented Shewanella oneidensis mutants. Phylogenetic analysis of the inner membrane quinol dehydrogenases CymA and NapC in gammaproteobacteria suggests that CymA from Shewanella diverged from Vibrionaceae CymA and NapC. Analysis of sequenced Vibrionaceae revealed that the genetic potential to perform EET is conserved in some members of the Harveyi and Vulnificus clades but is more variable in other clades. We provide evidence that EET enhances anaerobic survival of V. natriegens, which may be the primary physiological function for EET in Vibrionaceae. IMPORTANCE Bacteria from the genus Vibrio occupy a variety of marine and brackish niches with fluctuating nutrient and energy sources. When oxygen is limited, fermentation or alternative respiration pathways must be used to conserve energy. In sedimentary environments, insoluble oxide minerals (primarily iron and manganese) are able to serve as electron acceptors for anaerobic respiration by microorganisms capable of extracellular electron transfer, a metabolism that enables the use of these insoluble substrates. Here, we identify the mechanism for extracellular electron transfer in Vibrio natriegens, which uses a combination of strategies previously identified in Shewanella and Aeromonas. We show that extracellular electron transfer enhanced survival of V. natriegens under fermentative conditions, which may be a generalized strategy among Vibrio spp. predicted to have this metabolism.

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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

Applied and Environmental Microbiology ◽

10.1128/aem.00888-09 ◽

2009 ◽

Vol 75 (16) ◽

pp. 5209-5217 ◽

Cited By ~ 70

Author(s):

Justin L. Burns ◽

Thomas J. DiChristina

Keyword(s):

Gene Cluster ◽

Salmonella Enterica ◽

Elemental Sulfur ◽

Shewanella Oneidensis ◽

Anaerobic Respiration ◽

Sulfur Cycle ◽

Sulfur Compounds ◽

Electron Acceptors ◽

Inorganic Sulfur ◽

Serovar Typhimurium

ABSTRACT Shewanella oneidensis MR-1, a facultatively anaerobic gammaproteobacterium, respires a variety of anaerobic terminal electron acceptors, including the inorganic sulfur compounds sulfite (SO3 2−), thiosulfate (S2O3 2−), tetrathionate (S4O6 2−), and elemental sulfur (S0). The molecular mechanism of anaerobic respiration of inorganic sulfur compounds by S. oneidensis, however, is poorly understood. In the present study, we identified a three-gene cluster in the S. oneidensis genome whose translated products displayed 59 to 73% amino acid similarity to the products of phsABC, a gene cluster required for S0 and S2O3 2− respiration by Salmonella enterica serovar Typhimurium LT2. Homologs of phsA (annotated as psrA) were identified in the genomes of Shewanella strains that reduce S0 and S2O3 2− yet were missing from the genomes of Shewanella strains unable to reduce these electron acceptors. A new suicide vector was constructed and used to generate a markerless, in-frame deletion of psrA, the gene encoding the putative thiosulfate reductase. The psrA deletion mutant (PSRA1) retained expression of downstream genes psrB and psrC but was unable to respire S0 or S2O3 2− as the terminal electron acceptor. Based on these results, we postulate that PsrA functions as the main subunit of the S. oneidensis S2O3 2− terminal reductase whose end products (sulfide [HS−] or SO3 2−) participate in an intraspecies sulfur cycle that drives S0 respiration.

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Microbial selenium metabolism: a brief history, biogeochemistry and ecophysiology

FEMS Microbiology Ecology ◽

10.1093/femsec/fiaa209 ◽

2020 ◽

Vol 96 (12) ◽

Author(s):

Michael Wells ◽

John F Stolz

Keyword(s):

Common Ancestor ◽

Anaerobic Respiration ◽

Biogeochemical Cycle ◽

Aquatic Environments ◽

Selenium Metabolism ◽

Geologic Time ◽

Metabolic Functions ◽

Universal Common Ancestor ◽

Domains Of Life

ABSTRACT Selenium is an essential trace element for organisms from all three domains of life. Microorganisms, in particular, mediate reductive transformations of selenium that govern the element's mobility and bioavailability in terrestrial and aquatic environments. Selenium metabolism is not just ubiquitous but an ancient feature of life likely extending back to the universal common ancestor of all cellular lineages. As with the sulfur biogeochemical cycle, reductive transformations of selenium serve two metabolic functions: assimilation into macromolecules and dissimilatory reduction during anaerobic respiration. This review begins with a historical overview of how research in both aspects of selenium metabolism has developed. We then provide an overview of the global selenium biogeochemical cycle, emphasizing the central role of microorganisms in the cycle. This serves as a basis for a robust discussion of current models for the evolution of the selenium biogeochemical cycle over geologic time, and how knowledge of the evolution and ecophysiology of selenium metabolism can enrich and refine these models. We conclude with a discussion of the ecophysiological function of selenium-respiring prokaryotes within the cycle, and the tantalizing possibility of oxidative selenium transformations during chemolithoautotrophic growth.

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The role of membrane bound tetraheme CymA in the anaerobic respiration of Shewanella oneidensis MR-1

Biochemical Society Transactions ◽

10.1042/bst030a053 ◽

2002 ◽

Vol 30 (3) ◽

pp. A53-A53

Author(s):

C. Schwalb ◽

S. K. Chapman ◽

G. A. Reid

Keyword(s):

Shewanella Oneidensis ◽

Anaerobic Respiration ◽

Membrane Bound

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Involvement of a Membrane-Bound Class III Adenylate Cyclase in Regulation of Anaerobic Respiration in Shewanella oneidensis MR-1

Journal of Bacteriology ◽

10.1128/jb.01829-08 ◽

2009 ◽

Vol 191 (13) ◽

pp. 4298-4306 ◽

Cited By ~ 48

Author(s):

M. A. Charania ◽

K. L. Brockman ◽

Y. Zhang ◽

A. Banerjee ◽

G. E. Pinchuk ◽

...

Keyword(s):

Adenylate Cyclase ◽

Shewanella Oneidensis ◽

Anaerobic Respiration ◽

Receptor Protein ◽

Plasmid Replication ◽

Chromosomal Deletion ◽

Class Iii ◽

Membrane Bound ◽

Flagellum Biosynthesis ◽

Class Iv

ABSTRACT Unlike other bacteria that use FNR to regulate anaerobic respiration, Shewanella oneidensis MR-1 uses the cyclic AMP receptor protein (CRP) for this purpose. Three putative genes, cyaA, cyaB, and cyaC, predicted to encode class I, class IV, and class III adenylate cyclases, respectively, have been identified in the genome sequence of this bacterium. Functional validation through complementation of an Escherichia coli cya mutant confirmed that these genes encode proteins with adenylate cyclase activities. Chromosomal deletion of either cyaA or cyaB did not affect anaerobic respiration with fumarate, dimethyl sulfoxide (DMSO), or Fe(III), whereas deletion of cyaC caused deficiencies in respiration with DMSO and Fe(III) and, to a lesser extent, with fumarate. A phenotype similar to that of a crp mutant, which lacks the ability to grow anaerobically with DMSO, fumarate, and Fe(III), was obtained when both cyaA and cyaC were deleted. Microarray analysis of gene expression in the crp and cyaC mutants revealed the involvement of both genes in the regulation of key respiratory pathways, such as DMSO, fumarate, and Fe(III) reduction. Additionally, several genes associated with plasmid replication, flagellum biosynthesis, and electron transport were differentially expressed in the cyaC mutant but not in the crp mutant. Our results indicated that CyaC plays a major role in regulating anaerobic respiration and may contribute to additional signaling pathways independent of CRP.

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Impacts of Shewanella oneidensis c -type cytochromes on aerobic and anaerobic respiration

Microbial Biotechnology ◽

10.1111/j.1751-7915.2010.00181.x ◽

2010 ◽

Vol 3 (4) ◽

pp. 455-466 ◽

Cited By ~ 65

Author(s):

Haichun Gao ◽

Soumitra Barua ◽

Yili Liang ◽

Lin Wu ◽

Yangyang Dong ◽

...

Keyword(s):

Shewanella Oneidensis ◽

Anaerobic Respiration ◽

Aerobic And Anaerobic

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Aerobic Respiration and Its Regulation in the Metal Reducer Shewanella oneidensis

Frontiers in Microbiology ◽

10.3389/fmicb.2021.723835 ◽

2021 ◽

Vol 12 ◽

Author(s):

Kristen Bertling ◽

Areen Banerjee ◽

Daad Saffarini

Keyword(s):

Carbon Sources ◽

Shewanella Oneidensis ◽

Anaerobic Respiration ◽

Aerobic Respiration ◽

Wild Type ◽

Aerobic Growth ◽

Camp Phosphodiesterase ◽

Oxidase Gene ◽

Oxygen Reductase ◽

Mutant Phenotypes

Shewanella oneidensis MR-1 is a facultative anaerobe known for its ability to reduce metal oxides. Anaerobic respiration, especially metal reduction, has been the subject of extensive research. In contrast, S. oneidensis aerobic respiration has received less attention. S. oneidensis expresses cbb3- and aa3-type cytochrome c oxidases and a bd-type quinol oxidase. The aa3-type oxidase, which in other bacteria is the major oxygen reductase under oxygen replete conditions, does not appear to contribute to aerobic respiration and growth in S. oneidensis. Our results indicated that although the aa3-type oxidase does not play a role in aerobic growth on lactate, the preferred carbon source for S. oneidensis, it is involved in growth on pyruvate or acetate. These results highlight the importance of testing multiple carbon and energy sources when attempting to identify enzyme activities and mutant phenotypes. Several regulatory proteins contribute to the regulation of aerobic growth in S. oneidensis including CRP and ArcA. The 3',5'-cAMP phosphodiesterase (CpdA) appears to play a more significant role in aerobic growth than either CRP or ArcA, yet the deficiency does not appear to be the result of reduced oxidase genes expression. Interestingly, the ∆cpdA mutant was more deficient in aerobic respiration with several carbon sources tested compared to ∆crp, which was moderately deficient only in the presence of lactate. To identify the reason for ∆cpdA aerobic growth deficiency, we isolated a suppressor mutant with transposon insertion in SO_3550. Inactivation of this gene, which encodes an anti-sigma factor, restored aerobic growth in the cpdA mutant to wild-type levels. Inactivation of SO_3550 in wild-type cells, however, did not affect aerobic growth. The S. oneidensis genome encodes two additional CRP-like proteins that we designated CrpB and CrpC. Mutants that lack crpB and crpC were deficient in aerobic growth, but this deficiency was not due to the loss of oxidase gene expression.

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The membrane-bound tetrahaem c-type cytochrome CymA interacts directly with the soluble fumarate reductase in Shewanella

Biochemical Society Transactions ◽

10.1042/bst0300658 ◽

2002 ◽

Vol 30 (4) ◽

pp. 658-662 ◽

Cited By ~ 50

Author(s):

C. Schwalb ◽

S. K. Chapman ◽

G. A. Reid

Keyword(s):

Electron Transfer ◽

Outer Membrane ◽

Shewanella Oneidensis ◽

Anaerobic Respiration ◽

Fumarate Reductase ◽

Sulphur Compounds ◽

Sequence Alignments ◽

Membrane Bound ◽

Periplasmic Domain

Shewanella spp. demonstrate great variability in the use of terminal electron acceptors in anaerobic respiration; these include nitrate, fumarate, DMSO, trimethylamine oxide, sulphur compounds and metal oxides. These pathways open up possible applications in bioremediation. The wide variety of respiratory substrates for Shewanella is correlated with the evolution of several multi-haem membrane-bound, periplasmic and outer-membrane c-type cytochromes. The 21 kDa c-type cytochrome CymA of the freshwater strain Shewanella oneidensis MR-1 has an N-terminal membrane anchor and a globular tetrahaem periplasmic domain. According to sequence alignments, CymA is a member of the NapC/NirT family. This family of redox proteins is responsible for electron transfer from the quinone pool to periplasmic and outer-membrane-bound reductases. Prior investigations have shown that the absence of CymA results in loss of the ability to respire with Fe(III), fumarate and nitrate, indicating that CymA is involved in electron transfer to several terminal reductases. Here we describe the expression, purification and characterization of a soluble, truncated CymA (‘CymA). Potentiometric studies suggest that there are two pairs of haems with potentials of -175 and -261 mV and that ‘CymA is an efficient electron donor for the soluble fumarate reductase, flavocytochrome c3.

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Identification of Genes Involved in Cytochrome c Biogenesis in Shewanella oneidensis, Using a Modified mariner Transposon

Applied and Environmental Microbiology ◽

10.1128/aem.71.8.4935-4937.2005 ◽

2005 ◽

Vol 71 (8) ◽

pp. 4935-4937 ◽

Cited By ~ 66

Author(s):

R. Bouhenni ◽

A. Gehrke ◽

D. Saffarini

Keyword(s):

Cytochrome C ◽

Shewanella Oneidensis ◽

Anaerobic Respiration ◽

Rapid Identification ◽

Cytochrome C Biogenesis ◽

Transposon Insertions

ABSTRACT A modified mariner transposon, miniHimar RB1, was generated to mutagenize cells of the metal-reducing bacterium Shewanella oneidensis. The use of this transposon led to the isolation of stable mutants and allowed rapid identification of disrupted genes. Fifty-eight mutants, including BG104 and BG148 with transposon insertions in the cytochrome c maturation genes ccmC and ccmF1, respectively, were analyzed. Both mutants were deficient in anaerobic respiration and cytochrome c production.

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