Flavin-mediated extracellular electron transfer in Gram-positive bacteria Bacillus cereus DIF1 and Rhodococcus ruber DIF2

ABSTRACT Exoelectrogens are able to transfer electrons extracellularly, enabling them to respire on insoluble terminal electron acceptors. Extensively studied exoelectrogens, such as Geobacter sulfurreducens and Shewanella oneidensis, are Gram negative. More recently, it has been reported that Gram-positive bacteria, such as Listeria monocytogenes and Enterococcus faecalis, also exhibit the ability to transfer electrons extracellularly, although it is still unclear whether this has a function in respiration or in redox control of the environment, for instance, by reducing ferric iron for iron uptake. In this issue of Journal of Bacteriology, Hederstedt and colleagues report on experiments that directly compare extracellular electron transfer (EET) pathways for ferric iron reduction and respiration and find a clear difference (L. Hederstedt, L. Gorton, and G. Pankratova, J Bacteriol 202:e00725-19, 2020, https://doi.org/10.1128/JB.00725-19), providing further insights and new questions into the function and metabolic pathways of EET in Gram-positive bacteria.

Download Full-text

Faculty Opinions recommendation of A flavin-based extracellular electron transfer mechanism in diverse Gram-positive bacteria.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.734001876.793550856 ◽

2018 ◽

Author(s):

Angelika Gründling

Keyword(s):

Electron Transfer ◽

Transfer Mechanism ◽

Extracellular Electron Transfer ◽

Gram Positive ◽

Electron Transfer Mechanism ◽

Gram Positive Bacteria

Download Full-text

Extracellular electron transfer powers flavinylated extracellular reductases in Gram-positive bacteria

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1915678116 ◽

2019 ◽

Vol 116 (52) ◽

pp. 26892-26899 ◽

Cited By ~ 10

Author(s):

Samuel H. Light ◽

Raphaël Méheust ◽

Jessica L. Ferrell ◽

Jooyoung Cho ◽

David Deng ◽

...

Keyword(s):

Electron Transfer ◽

Phylogenetic Analyses ◽

Foodborne Pathogen ◽

Extracellular Electron Transfer ◽

Transfer System ◽

Gram Positive ◽

Gram Positive Bacteria ◽

Electron Transfer System ◽

Transport Chain ◽

Insoluble Electron Acceptors

Mineral-respiring bacteria use a process called extracellular electron transfer to route their respiratory electron transport chain to insoluble electron acceptors on the exterior of the cell. We recently characterized a flavin-based extracellular electron transfer system that is present in the foodborne pathogenListeria monocytogenes, as well as many other Gram-positive bacteria, and which highlights a more generalized role for extracellular electron transfer in microbial metabolism. Here we identify a family of putative extracellular reductases that possess a conserved posttranslational flavinylation modification. Phylogenetic analyses suggest that divergent flavinylated extracellular reductase subfamilies possess distinct and often unidentified substrate specificities. We show that flavinylation of a member of the fumarate reductase subfamily allows this enzyme to receive electrons from the extracellular electron transfer system and supportL. monocytogenesgrowth. We demonstrate that this represents a generalizable mechanism by finding that aL. monocytogenesstrain engineered to express a flavinylated extracellular urocanate reductase uses urocanate by a related mechanism and to a similar effect. These studies thus identify an enzyme family that exploits a modular flavin-based electron transfer strategy to reduce distinct extracellular substrates and support a multifunctional view of the role of extracellular electron transfer activities in microbial physiology.

Download Full-text

Extracellular electron transfer features of Gram-positive bacteria

Analytica Chimica Acta ◽

10.1016/j.aca.2019.05.007 ◽

2019 ◽

Vol 1076 ◽

pp. 32-47 ◽

Cited By ~ 31

Author(s):

Galina Pankratova ◽

Lars Hederstedt ◽

Lo Gorton

Keyword(s):

Electron Transfer ◽

Extracellular Electron Transfer ◽

Gram Positive ◽

Gram Positive Bacteria

Download Full-text

Novel Extracellular Electron Transfer Channels in a Gram-Positive Thermophilic Bacterium

Frontiers in Microbiology ◽

10.3389/fmicb.2020.597818 ◽

2021 ◽

Vol 11 ◽

Author(s):

Sergey N. Gavrilov ◽

Daria G. Zavarzina ◽

Ivan M. Elizarov ◽

Tamara V. Tikhonova ◽

Natalia I. Dergousova ◽

...

Keyword(s):

Electron Transfer ◽

Thermophilic Bacterium ◽

Hyperthermophilic Archaea ◽

Extracellular Electron Transfer ◽

Gram Positive ◽

Thermal Environments ◽

Gram Positive Bacteria ◽

Microscopic Studies ◽

First Time ◽

Transfer Channels

Biogenic transformation of Fe minerals, associated with extracellular electron transfer (EET), allows microorganisms to exploit high-potential refractory electron acceptors for energy generation. EET-capable thermophiles are dominated by hyperthermophilic archaea and Gram-positive bacteria. Information on their EET pathways is sparse. Here, we describe EET channels in the thermophilic Gram-positive bacterium Carboxydothermus ferrireducens that drive exoelectrogenesis and rapid conversion of amorphous mineral ferrihydrite to large magnetite crystals. Microscopic studies indicated biocontrolled formation of unusual formicary-like ultrastructure of the magnetite crystals and revealed active colonization of anodes in bioelectrochemical systems (BESs) by C. ferrireducens. The internal structure of micron-scale biogenic magnetite crystals is reported for the first time. Genome analysis and expression profiling revealed three constitutive c-type multiheme cytochromes involved in electron exchange with ferrihydrite or an anode, sharing insignificant homology with previously described EET-related cytochromes thus representing novel determinants of EET. Our studies identify these cytochromes as extracellular and reveal potentially novel mechanisms of cell-to-mineral interactions in thermal environments.

Download Full-text

Electrochemically Active Soluble Mediators from Shewanella oneidensis: Relevance to Microbial Fuel Cells and Extracellular Electron Transfer

ECS Meeting Abstracts ◽

10.1149/ma2008-01/7/230 ◽

2008 ◽

Keyword(s):

Electron Transfer ◽

Fuel Cells ◽

Microbial Fuel Cells ◽

Shewanella Oneidensis ◽

Extracellular Electron Transfer ◽

Electrochemically Active

Download Full-text

Long-distance electron transfer in a filamentous Gram-positive bacterium

Nature Communications ◽

10.1038/s41467-021-21709-z ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Yonggang Yang ◽

Zegao Wang ◽

Cuifen Gan ◽

Lasse Hyldgaard Klausen ◽

Robin Bonné ◽

...

Keyword(s):

Electron Transfer ◽

Microbial Fuel Cells ◽

Extracellular Electron Transfer ◽

Gram Negative Bacteria ◽

Positive Bacterium ◽

Long Distance ◽

Gram Positive ◽

Gram Negative ◽

Force Microscopy ◽

Cell Envelopes

AbstractLong-distance extracellular electron transfer has been observed in Gram-negative bacteria and plays roles in both natural and engineering processes. The electron transfer can be mediated by conductive protein appendages (in short unicellular bacteria such as Geobacter species) or by conductive cell envelopes (in filamentous multicellular cable bacteria). Here we show that Lysinibacillus varians GY32, a filamentous unicellular Gram-positive bacterium, is capable of bidirectional extracellular electron transfer. In microbial fuel cells, L. varians can form centimetre-range conductive cellular networks and, when grown on graphite electrodes, the cells can reach a remarkable length of 1.08 mm. Atomic force microscopy and microelectrode analyses suggest that the conductivity is linked to pili-like protein appendages. Our results show that long-distance electron transfer is not limited to Gram-negative bacteria.

Download Full-text

Antibacterial activity of Baccharis trimera (Less.) DC. (carqueja) against bacteria of medical interest

Revista CERES ◽

10.1590/s0034-737x2013000500019 ◽

2013 ◽

Vol 60 (5) ◽

pp. 731-734 ◽

Cited By ~ 4

Author(s):

Álan Alex Aleixo ◽

Karina Marjorie Silva Herrera ◽

Rosy Iara Maciel de Azambuja Ribeiro ◽

Luciana Alves Rodrigues dos Santos Lima ◽

Jaqueline Maria Siqueira Ferreira

Keyword(s):

Antibacterial Activity ◽

Folk Medicine ◽

Salmonella Typhi ◽

Bacterial Strains ◽

Gram Positive ◽

Gram Positive Bacteria ◽

Clinical Interest ◽

Antibacterial Susceptibility ◽

Baccharis Trimera ◽

Medical Interest

Baccharis trimera (Less.) (Asteraceae), popularly know as "carqueja", is a species commonly used in folk medicine for the treatment or prevention of diseases. In this context, the purpose of this work was to study the antibacterial activity of crude hydroalcoholic extract from Baccharis trimera against Gram-positive bacterial strains (Staphylococcus aureus ATCC 29213, Staphylococcus saprophyticus ATCC 15305, Staphylococcus epidermidis ATCC 12228, Enterococcus faecalis ATCC 19433) and Gram-negative bacteria (Escherichia coli EHEC ATCC 43895, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 27736, Salmonella typhi ATCC 19430) of clinical interest. Antibacterial susceptibility was evaluated by broth microdilution assay following the CLSI (formerly the NCCLS) guidelines. The extract from B. trimera showed antibacterial activity against Gram-positive bacteria and the most interesting result was obtained against S. epidermidis that presented Minimal Inhibitory Concentration of 250μg/mL. These results indicate that B. trimera have bacterisostatic potential against Gram-positive bacterial strains of medical interest and could serve as a base for further studies on the use of isolated compounds from this species as future antimicrobials.

Download Full-text