Blog
About

11
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Modular engineering to increase intracellular NAD(H/ +) promotes rate of extracellular electron transfer of Shewanella oneidensis

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The slow rate of extracellular electron transfer (EET) of electroactive microorganisms remains a primary bottleneck that restricts the practical applications of bioelectrochemical systems. Intracellular NAD(H/ +) (i.e., the total level of NADH and NAD +) is a crucial source of the intracellular electron pool from which intracellular electrons are transferred to extracellular electron acceptors via EET pathways. However, how the total level of intracellular NAD(H/ +) impacts the EET rate in Shewanella oneidensis has not been established. Here, we use a modular synthetic biology strategy to redirect metabolic flux towards NAD + biosynthesis via three modules: de novo, salvage, and universal biosynthesis modules in S. oneidensis MR-1. The results demonstrate that an increase in intracellular NAD(H/ +) results in the transfer of more electrons from the increased oxidation of the electron donor to the EET pathways of S. oneidensis, thereby enhancing intracellular electron flux and the EET rate.

          Abstract

          A bottleneck for the application of bioelectrochemical systems is the slow rate of extracellular electron transfer. Here the authors use a synthetic biology approach to redirect metabolic flux to NAD + biosynthesis, which enhances the intracellular electron flux and the extracellular electron transfer rate.

          Related collections

          Most cited references 66

          • Record: found
          • Abstract: found
          • Article: not found

          Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) Method.

          The two most commonly used methods to analyze data from real-time, quantitative PCR experiments are absolute quantification and relative quantification. Absolute quantification determines the input copy number, usually by relating the PCR signal to a standard curve. Relative quantification relates the PCR signal of the target transcript in a treatment group to that of another sample such as an untreated control. The 2(-Delta Delta C(T)) method is a convenient way to analyze the relative changes in gene expression from real-time quantitative PCR experiments. The purpose of this report is to present the derivation, assumptions, and applications of the 2(-Delta Delta C(T)) method. In addition, we present the derivation and applications of two variations of the 2(-Delta Delta C(T)) method that may be useful in the analysis of real-time, quantitative PCR data. Copyright 2001 Elsevier Science (USA).
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Tricine-SDS-PAGE.

            Tricine-SDS-PAGE is commonly used to separate proteins in the mass range 1-100 kDa. It is the preferred electrophoretic system for the resolution of proteins smaller than 30 kDa. The concentrations of acrylamide used in the gels are lower than in other electrophoretic systems. These lower concentrations facilitate electroblotting, which is particularly crucial for hydrophobic proteins. Tricine-SDS-PAGE is also used preferentially for doubled SDS-PAGE (dSDS-PAGE), a proteomic tool used to isolate extremely hydrophobic proteins for mass spectrometric identification, and it offers advantages for resolution of the second dimension after blue-native PAGE (BN-PAGE) and clear-native PAGE (CN-PAGE). Here I describe a protocol for Tricine-SDS-PAGE, which includes efficient methods for Coomassie blue or silver staining and electroblotting, thereby increasing the versatility of the approach. This protocol can be completed in 1-2 d.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Shewanella secretes flavins that mediate extracellular electron transfer.

              Bacteria able to transfer electrons to metals are key agents in biogeochemical metal cycling, subsurface bioremediation, and corrosion processes. More recently, these bacteria have gained attention as the transfer of electrons from the cell surface to conductive materials can be used in multiple applications. In this work, we adapted electrochemical techniques to probe intact biofilms of Shewanella oneidensis MR-1 and Shewanella sp. MR-4 grown by using a poised electrode as an electron acceptor. This approach detected redox-active molecules within biofilms, which were involved in electron transfer to the electrode. A combination of methods identified a mixture of riboflavin and riboflavin-5'-phosphate in supernatants from biofilm reactors, with riboflavin representing the dominant component during sustained incubations (>72 h). Removal of riboflavin from biofilms reduced the rate of electron transfer to electrodes by >70%, consistent with a role as a soluble redox shuttle carrying electrons from the cell surface to external acceptors. Differential pulse voltammetry and cyclic voltammetry revealed a layer of flavins adsorbed to electrodes, even after soluble components were removed, especially in older biofilms. Riboflavin adsorbed quickly to other surfaces of geochemical interest, such as Fe(III) and Mn(IV) oxy(hydr)oxides. This in situ demonstration of flavin production, and sequestration at surfaces, requires the paradigm of soluble redox shuttles in geochemistry to be adjusted to include binding and modification of surfaces. Moreover, the known ability of isoalloxazine rings to act as metal chelators, along with their electron shuttling capacity, suggests that extracellular respiration of minerals by Shewanella is more complex than originally conceived.
                Bookmark

                Author and article information

                Contributors
                hsong@tju.edu.cn
                Journal
                Nat Commun
                Nat Commun
                Nature Communications
                Nature Publishing Group UK (London )
                2041-1723
                7 September 2018
                7 September 2018
                2018
                : 9
                Affiliations
                [1 ]ISNI 0000 0004 1761 2484, GRID grid.33763.32, Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering, School of Chemical Engineering and Technology, , Tianjin University, ; Tianjin, 300072 PR China
                [2 ]ISNI 0000 0001 0373 6302, GRID grid.428986.9, State Key Laboratory of Marine Resource Utilization in South China Sea, College of Information Science & Technology, , Hainan University, ; Haikou, 570228 PR China
                [3 ]ISNI 0000 0004 0368 8293, GRID grid.16821.3c, State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, , Shanghai Jiao Tong University, ; Shanghai, 200240 PR China
                [4 ]Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geoscience in Wuhan, Wuhan, 430074 Hubei PR China
                Article
                5995
                10.1038/s41467-018-05995-8
                6128845
                30194293
                © The Author(s) 2018

                Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

                Funding
                Funded by: the Open Project Program of the State Key Lab of Marine Resource Utilization in South China Sea (Hainan University) granted (No. 2016010)
                Funded by: the State Key Laboratory of Microbial Metabolism (Shanghai Jiao Tong University, MMLKF 17-12)
                Funded by: the National Natural Science Foundation of China (NSFC 41630318, 41772363)
                Funded by: the National Natural Science Foundation of China (NSFC 21376174, 21621004), the National Basic Research Program of China (“973” Program: 2014CB745103), the Open Project Program of the State Key Lab of Marine Resource Utilization in South China Sea (Hainan University) granted (No. 2016010), and the State Key Laboratory of Microbial Metabolism (Shanghai Jiao Tong University, MMLKF 17-12).
                Categories
                Article
                Custom metadata
                © The Author(s) 2018

                Uncategorized

                Comments

                Comment on this article