Solving a shuttle mystery

Conley, Bridget; Gralnick, Jeffrey A.

doi:10.7554/elife.49831

Cited by 4 publications

(3 citation statements)

References 12 publications

(16 reference statements)

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“…About 2% of the DHNA pool can be transformed into ACNQ through a chemical reaction with NH 3 , and the remaining 98% is converted into DMK by 1,4‐dihydroxy‐2‐naphthoate heptaprenyltransferase (MenA). DMK can further be metabolized into menaquinone (MK), which is important in aerobic respiration, by demethylmenaquinone methyltransferase (UbiE) (Conley & Gralnick, 2019 ; Mevers et al, 2019 ). We determined the standard redox potential (E 0 ) of ACNQ and ferricyanide in GM17 to be close to −0.26 and 0.24 V vs. Ag/AgCl, respectively (Figure 4B,C ), thus thermodynamically ACNQ should be able to transfer electrons to ferricyanide.…”

Section: Resultsmentioning

confidence: 99%

Rewiring the respiratory pathway of Lactococcus lactis to enhance extracellular electron transfer

Xiao

Zhao

et al. 2023

Microbial Biotechnology

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Lactococcus lactis, a lactic acid bacterium with a typical fermentative metabolism, can also use oxygen as an extracellular electron acceptor. Here we demonstrate, for the first time, that L. lactis blocked in NAD + regeneration can use the alternative electron acceptor ferricyanide to support growth. By electrochemical analysis and characterization of strains carrying mutations in the respiratory chain, we pinpoint the essential role of the NADH dehydrogenase and 2-amino-3-carboxy-1,4-naphtoquinone in extracellular electron transfer (EET) and uncover the underlying pathway systematically. Ferricyanide respiration has unexpected effects on L. lactis, e.g., we find that morphology is altered from the normal coccoid to a more rod shaped appearance, and that acid resistance is increased. Using adaptive laboratory evolution (ALE), we successfully enhance the capacity for EET. Whole-genome sequencing reveals the underlying reason for the observed enhanced EET capacity to be a late-stage blocking of menaquinone biosynthesis. The perspectives of the study are numerous, especially within food fermentation and microbiome engineering, where EET can help relieve oxidative stress, promote growth of oxygen sensitive microorganisms and play critical roles in shaping microbial communities.

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Section: Resultsmentioning

confidence: 99%

Rewiring the respiratory pathway of Lactococcus lactis to enhance extracellular electron transfer

Xiao

Zhao

et al. 2023

Microbial Biotechnology

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“…Therefore, WO 3 would change its color when it is in contact with the electron-carrying cytochromes (Scheme 1b). 28,29 The directly donated electrons should be excluded in the measurement of the ES-transferred electrons.…”

Section: Resultsmentioning

confidence: 99%

Evaluating effectiveness of electron shuttles in environments with a WO₃ nanoprobe

Tian

Guan

et al. 2022

Environ. Sci.: Nano

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“…Extracellular respiratory bacteria (ERB) have evolved a unique extracellular electron transfer (EET) mechanism to thrive in anaerobic environments by respiring on diverse extracellular electron acceptors. − ERB play important roles in pollutant degradation, − energy harvesting, , chemical production, , and environmental remediation. , Various ERB, including Shewanella spp., Geobacter spp., Pseudomonas spp., and Listeria spp., have been identified from different habitats and characterized for their EET pathways. One of the most intensively studied ERB model bacteria is Shewanella oneidensis MR-1 .…”

Section: Introductionmentioning

confidence: 99%

Rediverting Electron Flux with an Engineered CRISPR-ddAsCpf1 System to Enhance the Pollutant Degradation Capacity of Shewanella oneidensis

Tang

et al. 2020

Environ. Sci. Technol.

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Pursuing efficient approaches to promote the extracellular electron transfer (EET) of extracellular respiratory bacteria is essential to their application in environmental remediation and waste treatment. Here, we report a new strategy of tuning electron flux by clustered regularly interspaced short palindromic repeat (CRISPR)-ddAsCpf1-based rediverting (namely STAR) to enhance the EET capacity of Shewanella oneidensis MR-1, a model extracellular respiratory bacterium widely present in the environment. The developed CRISPR-ddAsCpf1 system enabled approximately 100% gene repression with the green fluorescent protein (GFP) as a reporter. Using a WO 3 probe, 10 representative genes encoding for putative competitive electron transfer proteins were screened, among which 7 genes were identified as valid targets for EET enhancement. Repressing the valid genes not only increased the transcription level of the L-lactate metabolism genes but also affected the genes involved in direct and indirect EET. Increased riboflavin production was also observed. The feasibility of this strategy to enhance the bioreduction of methyl orange, an organic pollutant, and chromium, a typical heavy metal, was demonstrated. This work implies a great potential of the STAR strategy with the CIRPSR-ddAsCpf1 system for enhancing bacterial EET to favor more efficient environmental remediation applications.

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Solving a shuttle mystery

Abstract: Shewanella oneidensis bacteria use an abiotic reaction to help shuttle electrons outside of the cell.

Cited by 4 publications

References 12 publications

Rewiring the respiratory pathway of Lactococcus lactis to enhance extracellular electron transfer

Rewiring the respiratory pathway of Lactococcus lactis to enhance extracellular electron transfer

Evaluating effectiveness of electron shuttles in environments with a WO₃ nanoprobe

Rediverting Electron Flux with an Engineered CRISPR-ddAsCpf1 System to Enhance the Pollutant Degradation Capacity of Shewanella oneidensis

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Solving a shuttle mystery

Abstract: Shewanella oneidensis bacteria use an abiotic reaction to help shuttle electrons outside of the cell.

Cited by 4 publications

References 12 publications

Rewiring the respiratory pathway of Lactococcus lactis to enhance extracellular electron transfer

Rewiring the respiratory pathway of Lactococcus lactis to enhance extracellular electron transfer

Evaluating effectiveness of electron shuttles in environments with a WO3 nanoprobe

Rediverting Electron Flux with an Engineered CRISPR-ddAsCpf1 System to Enhance the Pollutant Degradation Capacity of Shewanella oneidensis

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Evaluating effectiveness of electron shuttles in environments with a WO₃ nanoprobe