Role of the Hya Hydrogenase in Recycling of Anaerobically Produced H
            <sub>2</sub>
            in
            <i>Salmonella enterica</i>
            Serovar Typhimurium

Zbell, Andrea L.; Maier, Robert J.

doi:10.1128/aem.02064-08

Cited by 46 publications

(53 citation statements)

References 21 publications

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“…1 study, a 10 ml sample was placed into a beaker and swirled for 10-15 s in air, and then (7 ml) evaluated aerobically for amperometric hydrogen consumption/evolution Zbell & Maier, 2009). Exposure to air inactivates the H 2 evolution enzymes (Zbell & Maier, 2009). For studying the effects of acid, stationary phase cells were added to vials (previously sparged with anaerobic mix) containing acid challenge medium, which was composed of buffered citric acid phosphate (Mcilvaine), pH 2.5.…”

Section: Methodsmentioning

confidence: 99%

“…Strains are wt (2457T), hya (ALZ44), hyb (ALZ47) and hyc (MMM01). Error bars, SD determined from five to eight replicate recordings of H 2 removal by individual strains, after inactivating H 2 evolution enzymes by brief O 2 treatment (Zbell & Maier, 2009). Asterisks indicate significant differences from wt at P,0.01 (*) and P,0.05 (**) based on Tukey's HSD method.…”

Section: Hydrogenase Activities Associated With Genetargeted Mutants mentioning

confidence: 99%

“…The Hya hydrogenase has been implicated as playing a role in Salmonella Typhimurium AR (Zbell & Maier, 2009). The Salmonella strain lacking Hya both is acid-sensitive and has a reduced ability to survive in RAW 264.7 macrophages compared with the wt (Zbell et al, 2008).…”

Section: Acid Challengementioning

confidence: 99%

“…For the Fig. 1 study, a 10 ml sample was placed into a beaker and swirled for 10-15 s in air, and then (7 ml) evaluated aerobically for amperometric hydrogen consumption/evolution Zbell & Maier, 2009). Exposure to air inactivates the H 2 evolution enzymes (Zbell & Maier, 2009).…”

Section: Methodsmentioning

confidence: 99%

“…Due to the membrane orientation of the H 2 oxidation reactions, the model for hydrogenase-mediated proton motive force (PMF) generation involves the deposition of protons at the periplasm so that ATP production or other work can be accomplished by the cell (Brøndsted & Atlung, 1994;Vignais & Colbeau, 2004). In Enterobacteriaceae, it is believed that the Hya hydrogenase is the primary enzyme to recycle protons and electrons originally produced anaerobically by the formate hydrogenlyase complex (Redwood et al, 2008;Zbell & Maier, 2009). One component of FHL is HycE, a hydrogen-evolving enzyme (Redwood et al, 2008;Sawers, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Roles of H2 uptake hydrogenases in Shigella flexneri acid tolerance

McNorton

Maier

2012

Microbiology

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Hydrogenases play many roles in bacterial physiology, and use of H 2 by the uptake-type enzymes of animal pathogens is of particular interest. Hydrogenases have never been studied in the pathogen Shigella, so targeted mutant strains were individually generated in the two Shigella flexneri H 2 -uptake enzymes (Hya and Hyb) and in the H 2 -evolving enzyme (Hyc) to address their roles. Under anaerobic fermentative conditions, a Hya mutant strain (hya) was unable to oxidize H 2 , while a Hyb mutant strain oxidized H 2 like the wild-type. A hyc strain oxidized more exogenously added hydrogen than the parent. Fluorescence ratio imaging with dye JC-1 (5, 59,6,69-tetrachloro-1,19,3,39-tetraethylbenzimidazolylcarbocyanine iodide) showed that the parent strain generated a membrane potential 15 times greater than hya. The hya mutant was also by far the most acid-sensitive strain, being even more acid-sensitive than a mutant strain in the known acid-combating glutamate-dependent acid-resistance pathway (GDAR pathway). In severe acid-challenge experiments, the addition of glutamate to hya restored survivability, and this ability was attributed in part to the GDAR system (removes intracellular protons) by mutant strain (e.g. hya/gadBC double mutant) analyses. However, mutant strain phenotypes indicated that a larger portion of the glutamate-rescued acid tolerance was independent of GadBC. The acid tolerance of the hya strains was aided by adding chloride ions to the growth medium. The wholecell Hya enzyme became more active upon acid exposure (20 min), based on assays of hyc. Indeed, the very high rates of Shigella H 2 oxidation by Hya in acid can supply each cell with 2.4¾10 8 protons min "1 . Electrons generated from Hya-mediated H 2 oxidation at the inner membrane likely counteract cytoplasmic positive charge stress, while abundant proton pools deposited periplasmically likely repel proton influx during severe acid stress.

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Section: Methodsmentioning

confidence: 99%

Section: Hydrogenase Activities Associated With Genetargeted Mutants mentioning

confidence: 99%